bims-mepmim 2023-05-28 papers

bims-mepmim

Biomed News

on Metabolites in pathological microenvironments and immunometabolism

Issue of 2023‒05‒28
thirty-one papers selected by
Erika Mariana Palmieri
NIH/NCI Laboratory of Cancer ImmunoMetabolism

Electron transport chain inhibition increases cellular dependence on purine transport and salvage.
Transcriptional and metabolic programs promote the expansion of follicular helper T cells in lupus-prone mice.
Metabolic landscape of the male mouse gut identifies different niches determined by microbial activities.
Macrophage angiotensin-converting enzyme (ACE) reduces atherosclerosis by increasing PPARα and fundamentally changing lipid metabolism.
Proteolytic rewiring of mitochondria by LONP1 directs cell identity switching of adipocytes.
Cellular-scale proximity labeling for recording cell spatial organization in mouse tissues.
Oxygen-induced pathological angiogenesis promotes intense lipid synthesis and remodeling in the retina.
miRNA-1 promotes acute myeloid leukemia cell pathogenesis through metabolic regulation.
Divergent metabolic programmes control two populations of MAIT cells that protect the lung.
Glycerol as a precursor for hepatic de novo glutathione synthesis in human liver.
Structures of human SGLT in the occluded state reveal conformational changes during sugar transport.
Gene and protein expression and metabolic flux analysis reveals metabolic scaling in liver ex vivo and in vivo.
A coordinated multiorgan metabolic response contributes to human mitochondrial myopathy.
Enhanced mitochondrial fission inhibits triple-negative breast cancer cell migration through an ROS-dependent mechanism.
MAP4K3 inhibits Sirtuin-1 to repress the LKB1-AMPK pathway to promote amino acid-dependent activation of the mTORC1 complex.
Context-dependent activation of STING-interferon signaling by CD11b agonists enhances anti-tumor immunity.
FOXK1 promotes nonalcoholic fatty liver disease by mediating mTORC1-dependent inhibition of hepatic fatty acid oxidation.
The AE4 transporter mediates kidney acid-base sensing.
The enteric nervous system relays psychological stress to intestinal inflammation.
Tumour extracellular vesicles and particles induce liver metabolic dysfunction.
Alanine supplementation exploits glutamine dependency induced by SMARCA4/2-loss.
Alternatively activated lung alveolar and interstitial macrophages promote fungal growth.
Tissue-resident memory CAR T cells with stem-like characteristics display enhanced efficacy against solid and liquid tumors.
The transcriptional control of the VEGFA-VEGFR1 (FLT1) axis in alternatively polarized murine and human macrophages.
Get me out of here: Sphingosine 1-phosphate signaling and T cell exit from tissues during an immune response.
Small-molecule MHC-II inducers promote immune detection and anti-cancer immunity via editing cancer metabolism.
Pyruvate dehydrogenase complex integrates the metabolome and epigenome in CD8+ memory T cell differentiation in vitro.
Depletion of CUL4B in macrophages ameliorates diabetic kidney disease via miR-194-5p/ITGA9 axis.
Genetically encoded photocatalytic protein labeling enables spatially-resolved profiling of intracellular proteome.
γ-Linolenic acid in maternal milk drives cardiac metabolic maturation.
Nitric oxide synthase and reduced arterial tone contribute to arteriovenous malformation.

bioRxiv. 2023 May 11. pii: 2023.05.11.540429. [Epub ahead of print]

Electron transport chain inhibition increases cellular dependence on purine transport and salvage.

Zheng Wu, Divya Bezwada, Robert C Harris, Chunxiao Pan, Phong T Nguyen, Brandon Faubert, Ling Cai, Feng Cai, Hieu S Vu, Hongli Chen, Misty Martin- Sandoval, Duyen Do, Wen Gu, Yuannyu Zhang, Bookyung Ko, Bailey Brooks, Sherwin Kelekar, Yuanyuan Zhang, Lauren G Zacharias, K Celeste Oaxaca, Thomas P Mathews, Javier Garcia-Bermudez, Min Ni, Ralph J DeBerardinis.

Cancer cells reprogram their metabolism to support cell growth and proliferation in harsh environments. While many studies have documented the importance of mitochondrial oxidative phosphorylation (OXPHOS) in tumor growth, some cancer cells experience conditions of reduced OXPHOS in vivo and induce alternative metabolic pathways to compensate. To assess how human cells respond to mitochondrial dysfunction, we performed metabolomics in fibroblasts and plasma from patients with inborn errors of mitochondrial metabolism, and in cancer cells subjected to inhibition of the electron transport chain (ETC). All these analyses revealed extensive perturbations in purine-related metabolites; in non-small cell lung cancer (NSCLC) cells, ETC blockade led to purine metabolite accumulation arising from a reduced cytosolic NAD + /NADH ratio (NADH reductive stress). Stable isotope tracing demonstrated that ETC deficiency suppressed de novo purine nucleotide synthesis while enhancing purine salvage. Analysis of NSCLC patients infused with [U- 13 C]glucose revealed that tumors with markers of low oxidative mitochondrial metabolism exhibited high expression of the purine salvage enzyme HPRT1 and abundant levels of the HPRT1 product inosine monophosphate (IMP). ETC blockade also induced production of ribose-5' phosphate (R5P) by the pentose phosphate pathway (PPP) and import of purine nucleobases. Blocking either HPRT1 or nucleoside transporters sensitized cancer cells to ETC inhibition, and overexpressing nucleoside transporters was sufficient to drive growth of NSCLC xenografts. Collectively, this study mechanistically delineates how cells compensate for suppressed purine metabolism in response to ETC blockade, and uncovers a new metabolic vulnerability in tumors experiencing NADH excess.

DOI: https://doi.org/10.1101/2023.05.11.540429
iScience. 2023 May 19. 26(5): 106774

Transcriptional and metabolic programs promote the expansion of follicular helper T cells in lupus-prone mice.

Minghao Gong, Seung-Chul Choi, Yuk Pheel Park, Xueyang Zou, Ahmed S Elshikha, Valerie A Gerriets, Jeffrey C Rathmell, Mansour Mohamazadeh, Laurence Morel.

  The expansion of follicular helper T (Tfh) cells, which is tightly associated with the development of lupus, is reversed by the inhibition of either glycolysis or glutaminolysis in mice. Here we analyzed the gene expression and metabolome of Tfh cells and naive CD4+ T (Tn) cells in the B6.Sle1.Sle2.Sle3 (triple congenic, TC) mouse model of lupus and its congenic B6 control. Lupus genetic susceptibility in TC mice drives a gene expression signature starting in Tn cells and expanding in Tfh cells with enhanced signaling and effector programs. Metabolically, TC Tn and Tfh cells showed multiple defective mitochondrial functions. TC Tfh cells also showed specific anabolic programs including enhanced glutamate metabolism, malate-aspartate shuttle, and ammonia recycling, as well as altered dynamics of amino acid content and their transporters. Thus, our study has revealed specific metabolic programs that can be targeted to specifically limit the expansion of pathogenic Tfh cells in lupus.

Keywords:  Cell biology; Immunology; Metabolomics; Physiology; Transcriptomics

DOI:  https://doi.org/10.1016/j.isci.2023.106774
Nat Metab. 2023 May 22.

Metabolic landscape of the male mouse gut identifies different niches determined by microbial activities.

Karin H U Meier, Julian Trouillon, Hai Li, Melanie Lang, Tobias Fuhrer, Nicola Zamboni, Shinichi Sunagawa, Andrew J Macpherson, Uwe Sauer.

Distinct niches of the mammalian gut are populated by diverse microbiota, but the contribution of spatial variation to intestinal metabolism remains unclear. Here we present a map of the longitudinal metabolome along the gut of healthy colonized and germ-free male mice. With this map, we reveal a general shift from amino acids in the small intestine to organic acids, vitamins and nucleotides in the large intestine. We compare the metabolic landscapes in colonized versus germ-free mice to disentangle the origin of many metabolites in different niches, which in some cases allows us to infer the underlying processes or identify the producing species. Beyond the known impact of diet on the small intestinal metabolic niche, distinct spatial patterns suggest specific microbial influence on the metabolome in the small intestine. Thus, we present a map of intestinal metabolism and identify metabolite-microbe associations, which provide a basis to connect the spatial occurrence of bioactive compounds to host or microorganism metabolism.

DOI: https://doi.org/10.1038/s42255-023-00802-1
Cardiovasc Res. 2023 May 24. pii: cvad082. [Epub ahead of print]

Macrophage angiotensin-converting enzyme (ACE) reduces atherosclerosis by increasing PPARα and fundamentally changing lipid metabolism.

DuoYao Cao, Zakir Khan, Xiaomo Li, Suguru Saito, Ellen A Bernstein, Aaron R Victor, Faizan Ahmed, Aoi O Hoshi, Luciana C Veiras, Tomohiro Shibata, Mingtian Che, Lei Cai, Ryan E Temel, Jorge F Giani, Daniel J Luthringer, Ajit S Divakaruni, Derick Okwan-Duodu, Kenneth E Bernstein.

AIMS: The metabolic failure of macrophages to adequately process lipid is central to the etiology of atherosclerosis. Here, we examine the role of macrophage angiotensin converting enzyme (ACE) in a mouse model of PCSK9 induced atherosclerosis.METHODS AND RESULTS: Atherosclerosis in mice was induced with AAV-PCSK9 and a high fat diet. Animals with increased macrophage ACE (ACE 10/10 mice) have a marked reduction in atherosclerosis vs. WT mice. Macrophages from both the aorta and peritoneum of ACE 10/10 express increased PPARα and have a profoundly altered phenotype to process lipids characterized by higher levels of the surface scavenger receptor CD36, increased uptake of lipid, increased capacity to transport long chain fatty acids into mitochondria, higher oxidative metabolism and lipid β-oxidation as determined using 13C isotope tracing, increased cell ATP, increased capacity for efferocytosis, increased concentrations of the lipid transporters ABCA1 and ABCG1, and increased cholesterol efflux. These effects are mostly independent of angiotensin II. Human THP-1 cells, when modified to express more ACE, increase expression of PPARα, increase cell ATP and acetyl-CoA, and increase cell efferocytosis.
CONCLUSION AND TRANSLATIONAL PERSPECTIVE: Increased macrophage ACE expression enhances macrophage lipid metabolism, cholesterol efflux, efferocytosis, and it reduces atherosclerosis. This has implications for the treatment of cardiovascular disease with angiotensin II receptor antagonists (ARBs) vs. ACE inhibitors.

DOI: https://doi.org/10.1093/cvr/cvad082
Nat Cell Biol. 2023 May 22.

Proteolytic rewiring of mitochondria by LONP1 directs cell identity switching of adipocytes.

Tingting Fu, Wanping Sun, Jiachen Xue, Zheng Zhou, Wen Wang, Qiqi Guo, Xinyi Chen, Danxia Zhou, Zhisheng Xu, Lin Liu, Liwei Xiao, Yan Mao, Likun Yang, Yujing Yin, Xue-Na Zhang, Qiangyou Wan, Bin Lu, Yuncong Chen, Min-Sheng Zhu, Philipp E Scherer, Lei Fang, Hai-Long Piao, Mengle Shao, Zhenji Gan.

Mitochondrial proteases are emerging as key regulators of mitochondrial plasticity and acting as both protein quality surveillance and regulatory enzymes by performing highly regulated proteolytic reactions. However, it remains unclear whether the regulated mitochondrial proteolysis is mechanistically linked to cell identity switching. Here we report that cold-responsive mitochondrial proteolysis is a prerequisite for white-to-beige adipocyte cell fate programming during adipocyte thermogenic remodelling. Thermogenic stimulation selectively promotes mitochondrial proteostasis in mature white adipocytes via the mitochondrial protease LONP1. Disruption of LONP1-dependent proteolysis substantially impairs cold- or β3 adrenergic agonist-induced white-to-beige identity switching of mature adipocytes. Mechanistically, LONP1 selectively degrades succinate dehydrogenase complex iron sulfur subunit B and ensures adequate intracellular succinate levels. This alters the histone methylation status on thermogenic genes and thereby enables adipocyte cell fate programming. Finally, augmented LONP1 expression raises succinate levels and corrects ageing-related impairments in white-to-beige adipocyte conversion and adipocyte thermogenic capacity. Together, these findings reveal that LONP1 links proteolytic surveillance to mitochondrial metabolic rewiring and directs cell identity conversion during adipocyte thermogenic remodelling.

DOI: https://doi.org/10.1038/s41556-023-01155-3
Sci Adv. 2023 May 26. 9(21): eadg6388

Cellular-scale proximity labeling for recording cell spatial organization in mouse tissues.

Xu Zhang, Qi Tang, Jiayu Sun, Yilan Guo, Shaoran Zhang, Shuyu Liang, Peng Dai, Xing Chen.

Proximity labeling has emerged as a powerful strategy for interrogating cell-cell interactions. However, the nanometer-scale labeling radius impedes the use of current methods for indirect cell communications and makes recording cell spatial organization in tissue samples difficult. Here, we develop quinone methide-assisted identification of cell spatial organization (QMID), a chemical strategy with the labeling radius matching the cell dimension. The activating enzyme is installed on the surface of bait cells, which produces QM electrophiles that can diffuse across micrometers and label proximal prey cells independent of cell-cell contacts. In cell coculture, QMID reveals gene expression of macrophages that are regulated by spatial proximity to tumor cells. Furthermore, QMID enables labeling and isolation of proximal cells of CD4+ and CD8+ T cells in the mouse spleen, and subsequent single-cell RNA sequencing uncovers distinctive cell populations and gene expression patterns within the immune niches of specific T cell subtypes. QMID should facilitate dissecting cell spatial organization in various tissues.

DOI: https://doi.org/10.1126/sciadv.adg6388
iScience. 2023 Jun 16. 26(6): 106777

Oxygen-induced pathological angiogenesis promotes intense lipid synthesis and remodeling in the retina.

Alex Inague, Lilian Costa Alecrim, Jhonatas Sirino Monteiro, Marcos Yukio Yoshinaga, João Carlos Setubal, Sayuri Miyamoto, Ricardo José Giordano.

  The retina is a notable tissue with high metabolic needs which relies on specialized vascular networks to protect the neural retina while maintaining constant supplies of oxygen, nutrients, and dietary essential fatty acids. Here we analyzed the lipidome of the mouse retina under healthy and pathological angiogenesis using the oxygen-induced retinopathy model. By matching lipid profiles to changes in mRNA transcriptome, we identified a lipid signature showing that pathological angiogenesis leads to intense lipid remodeling favoring pathways for neutral lipid synthesis, cholesterol import/export, and lipid droplet formation. Noteworthy, it also shows profound changes in pathways for long-chain fatty acid production, vital for retina homeostasis. The net result is accumulation of large quantities of mead acid, a marker of essential fatty acid deficiency, and a potential marker for retinopathy severity. Thus, our lipid signature might contribute to better understand diseases of the retina that lead to vision impairment or blindness.

Keywords:  Metabolomics; Molecular mechanism of behavior

DOI:  https://doi.org/10.1016/j.isci.2023.106777
Front Genet. 2023 ;14 1192799

miRNA-1 promotes acute myeloid leukemia cell pathogenesis through metabolic regulation.

Arevik Ghazaryan, Jared A Wallace, William W Tang, Cindy Barba, Soh-Hyun Lee, Kaylyn M Bauer, Morgan C Nelson, Carissa N Kim, Chris Stubben, Warren P Voth, Dinesh S Rao, Ryan M O'Connell.

  Acute myeloid leukemia (AML) is a heterogeneous and deadly disease characterized by uncontrolled expansion of malignant blasts. Altered metabolism and dysregulated microRNA (miRNA) expression profiles are both characteristic of AML. However, there is a paucity of studies exploring how changes in the metabolic state of the leukemic cells regulate miRNA expression leading to altered cellular behavior. Here, we blocked pyruvate entry into mitochondria by deleting the Mitochondria Pyruvate Carrier (MPC1) gene in human AML cell lines, which decreased Oxidative Phosphorylation (OXPHOS). This metabolic shift also led to increased expression of miR-1 in the human AML cell lines tested. AML patient sample datasets showed that higher miR-1 expression correlates with reduced survival. Transcriptional and metabolic profiling of miR-1 overexpressing AML cells revealed that miR-1 increased OXPHOS, along with key metabolites that fuel the TCA cycle such as glutamine and fumaric acid. Inhibition of glutaminolysis decreased OXPHOS in miR-1 overexpressing MV4-11 cells, highlighting that miR-1 promotes OXPHOS through glutaminolysis. Finally, overexpression of miR-1 in AML cells exacerbated disease in a mouse xenograft model. Together, our work expands current knowledge within the field by uncovering novel connections between AML cell metabolism and miRNA expression that facilitates disease progression. Further, our work points to miR-1 as a potential new therapeutic target that may be used to disrupt AML cell metabolism and thus pathogenesis in the clinic.

Keywords:  OxPhos; acute myeloid leukemia; hematological malignancies; microRNA-1; prognostic biomarker

DOI:  https://doi.org/10.3389/fgene.2023.1192799
Nat Cell Biol. 2023 May 25.

Divergent metabolic programmes control two populations of MAIT cells that protect the lung.

Thomas Riffelmacher, Mallory Paynich Murray, Chantal Wientjens, Shilpi Chandra, Viankail Cedillo-Castelán, Ting-Fang Chou, Sara McArdle, Christopher Dillingham, Jordan Devereaux, Aaron Nilsen, Simon Brunel, David M Lewinsohn, Jeff Hasty, Gregory Seumois, Christopher A Benedict, Pandurangan Vijayanand, Mitchell Kronenberg.

Although mucosal-associated invariant T (MAIT) cells provide rapid, innate-like responses, they are not pre-set, and memory-like responses have been described for MAIT cells following infections. The importance of metabolism for controlling these responses, however, is unknown. Here, following pulmonary immunization with a Salmonella vaccine strain, mouse MAIT cells expanded as separate CD127-Klrg1+ and CD127+Klrg1- antigen-adapted populations that differed in terms of their transcriptome, function and localization in lung tissue. These populations remained altered from steady state for months as stable, separate MAIT cell lineages with enhanced effector programmes and divergent metabolism. CD127+ MAIT cells engaged in an energetic, mitochondrial metabolic programme, which was critical for their maintenance and IL-17A synthesis. This programme was supported by high fatty acid uptake and mitochondrial oxidation and relied on highly polarized mitochondria and autophagy. After vaccination, CD127+ MAIT cells protected mice against Streptococcus pneumoniae infection. In contrast, Klrg1+ MAIT cells had dormant but ready-to-respond mitochondria and depended instead on Hif1a-driven glycolysis to survive and produce IFN-γ. They responded antigen independently and participated in protection from influenza virus. These metabolic dependencies may enable tuning of memory-like MAIT cell responses for vaccination and immunotherapies.

DOI: https://doi.org/10.1038/s41556-023-01152-6
Redox Biol. 2023 May 16. pii: S2213-2317(23)00150-7. [Epub ahead of print]63 102749

Glycerol as a precursor for hepatic de novo glutathione synthesis in human liver.

Eunsook S Jin, Craig R Malloy, Gaurav Sharma, Erin Finn, Kelly N Z Fuller, Yesenia Garcia Reyes, Mark A Lovell, Sarkis C Derderian, Jonathan A Schoen, Thomas H Inge, Melanie G Cree.

  BACKGROUND: Glycerol is a substrate for gluconeogenesis and fatty acid esterification in the liver, processes which are upregulated in obesity and may contribute to excess fat accumulation. Glycine and glutamate, in addition to cysteine, are components of glutathione, the major antioxidant in the liver. In principle, glycerol could be incorporated into glutathione via the TCA cycle or 3-phosphoglycerate, but it is unknown whether glycerol contributes to hepatic de novo glutathione biosynthesis.METHODS: Glycerol metabolism to hepatic metabolic products including glutathione was examined in the liver from adolescents undergoing bariatric surgery. Participants received oral [U-13C3]glycerol (50 mg/kg) prior to surgery and liver tissue (0.2-0.7g) was obtained during surgery. Glutathione, amino acids, and other water-soluble metabolites were extracted from the liver tissue and isotopomers were quantified with nuclear magnetic resonance spectroscopy.
RESULTS: Data were collected from 8 participants (2 male, 6 female; age 17.1 years [range 14-19]; BMI 47.4 kg/m2 [range 41.3-63.3]). The concentrations of free glutamate, cysteine, and glycine were similar among participants, and so were the fractions of 13C-labeled glutamate and glycine derived from [U-13C3]glycerol. The signals from all component amino acids of glutathione - glutamate, cysteine and glycine - were strong and analyzed to obtain the relative concentrations of the antioxidant in the liver. The signals from glutathione containing [13C2]glycine or [13C2]glutamate derived from the [U-13C3]glycerol drink were readily detected, and 13C-labelling patterns in the moieties were consistent with the patterns in corresponding free amino acids from the de novo glutathione synthesis pathway. The newly synthesized glutathione with [U-13C3]glycerol trended to be lower in obese adolescents with liver pathology.
CONCLUSIONS: This is the first report of glycerol incorporation into glutathione through glycine or glutamate metabolism in human liver. This could represent a compensatory mechanism to increase glutathione in the setting of excess glycerol delivery to the liver.

Keywords:  Cysteine; Glutamate; Glutathione; Glycerol; Glycine; Liver; NMR; Stable isotope

DOI:  https://doi.org/10.1016/j.redox.2023.102749
Nat Commun. 2023 May 22. 14(1): 2920

Structures of human SGLT in the occluded state reveal conformational changes during sugar transport.

Wenhao Cui, Yange Niu, Zejian Sun, Rui Liu, Lei Chen.

Sodium-Glucose Cotransporters (SGLT) mediate the uphill uptake of extracellular sugars and play fundamental roles in sugar metabolism. Although their structures in inward-open and outward-open conformations are emerging from structural studies, the trajectory of how SGLTs transit from the outward-facing to the inward-facing conformation remains unknown. Here, we present the cryo-EM structures of human SGLT1 and SGLT2 in the substrate-bound state. Both structures show an occluded conformation, with not only the extracellular gate but also the intracellular gate tightly sealed. The sugar substrate are caged inside a cavity surrounded by TM1, TM2, TM3, TM6, TM7, and TM10. Further structural analysis reveals the conformational changes associated with the binding and release of substrates. These structures fill a gap in our understanding of the structural mechanisms of SGLT transporters.

DOI: https://doi.org/10.1038/s41467-023-38720-1
Elife. 2023 May 23. pii: e78335. [Epub ahead of print]12

Gene and protein expression and metabolic flux analysis reveals metabolic scaling in liver ex vivo and in vivo.

Ngozi D Akingbesote, Brooks P Leitner, Daniel G Jovin, Reina Desrouleaux, Dennis Owusu, Wanling Zhu, Zongyu Li, Michael N Pollak, Rachel J Perry.

  Metabolic scaling, the inverse correlation of metabolic rates to body mass, has been appreciated for more than 80 years. Studies of metabolic scaling have largely been restricted to mathematical modeling of caloric intake and oxygen consumption, and mostly rely on computational modeling. The possibility that other metabolic processes scale with body size has not been comprehensively studied. To address this gap in knowledge, we employed a systems approach including transcriptomics, proteomics, and measurement of in vitro and in vivo metabolic fluxes. Gene expression in livers of five species spanning a 30,000-fold range in mass revealed differential expression according to body mass of genes related to cytosolic and mitochondrial metabolic processes, and to detoxication of oxidative damage. To determine whether flux through key metabolic pathways is ordered inversely to body size, we applied stable isotope tracer methodology to study multiple cellular compartments, tissues, and species. Comparing C57BL/6 J mice with Sprague-Dawley rats, we demonstrate that while ordering of metabolic fluxes is not observed in in vitro cell-autonomous settings, it is present in liver slices and in vivo. Together, these data reveal that metabolic scaling extends beyond oxygen consumption to other aspects of metabolism, and is regulated at the level of gene and protein expression, enzyme activity, and substrate supply.

Keywords:  biochemistry; chemical biology; liver metabolism; metabolic flux; metabolic scaling; mouse; rat

DOI:  https://doi.org/10.7554/eLife.78335
EMBO Mol Med. 2023 May 24. e16951

A coordinated multiorgan metabolic response contributes to human mitochondrial myopathy.

Nneka Southwell, Guido Primiano, Viraj Nadkarni, Nabeel Attarwala, Emelie Beattie, Dawson Miller, Sumaitaah Alam, Irene Liparulo, Yevgeniya I Shurubor, Maria Lucia Valentino, Valerio Carelli, Serenella Servidei, Steven S Gross, Giovanni Manfredi, Qiuying Chen, Marilena D'Aurelio.

  Mitochondrial diseases are a heterogeneous group of monogenic disorders that result from impaired oxidative phosphorylation (OXPHOS). As neuromuscular tissues are highly energy-dependent, mitochondrial diseases often affect skeletal muscle. Although genetic and bioenergetic causes of OXPHOS impairment in human mitochondrial myopathies are well established, there is a limited understanding of metabolic drivers of muscle degeneration. This knowledge gap contributes to the lack of effective treatments for these disorders. Here, we discovered fundamental muscle metabolic remodeling mechanisms shared by mitochondrial disease patients and a mouse model of mitochondrial myopathy. This metabolic remodeling is triggered by a starvation-like response that evokes accelerated oxidation of amino acids through a truncated Krebs cycle. While initially adaptive, this response evolves in an integrated multiorgan catabolic signaling, lipid store mobilization, and intramuscular lipid accumulation. We show that this multiorgan feed-forward metabolic response involves leptin and glucocorticoid signaling. This study elucidates systemic metabolic dyshomeostasis mechanisms that underlie human mitochondrial myopathies and identifies potential new targets for metabolic intervention.

Keywords:  amino acid metabolism; glucocorticoids; leptin; mitochondrial myopathy; muscle wasting

DOI:  https://doi.org/10.15252/emmm.202216951
iScience. 2023 Jun 16. 26(6): 106788

Enhanced mitochondrial fission inhibits triple-negative breast cancer cell migration through an ROS-dependent mechanism.

Brock A Humphries, Anne Zhang, Johanna M Buschhaus, Avinash Bevoor, Alex Farfel, Shrila Rajendran, Alyssa C Cutter, Gary D Luker.

  Mitochondria produce reactive oxygen species (ROS), which function in signal transduction. Mitochondrial dynamics, encompassing morphological shifts between fission and fusion, can directly impact ROS levels in cancer cells. In this study, we identified an ROS-dependent mechanism for how enhanced mitochondrial fission inhibits triple negative breast cancer (TNBC) cell migration. We found that enforcing mitochondrial fission in TNBC resulted in an increase in intracellular ROS levels and reduced cell migration and the formation of actin-rich migratory structures. Consistent with mitochondrial fission, increasing ROS levels in cells inhibited cell migration. Conversely, reducing ROS levels with either a global or mitochondrially targeted scavenger overcame the inhibitory effects of mitochondrial fission. Mechanistically, we found that the ROS sensitive SHP-1/2 phosphatases partially regulate inhibitory effects of mitochondrial fission on TNBC migration. Overall, our work reveals the inhibitory effects of ROS in TNBC and supports mitochondrial dynamics as a potential therapeutic target for cancer.

Keywords:  Cancer; Cell biology

DOI:  https://doi.org/10.1016/j.isci.2023.106788
Life Sci Alliance. 2023 08;pii: e202201525. [Epub ahead of print]6(8):

MAP4K3 inhibits Sirtuin-1 to repress the LKB1-AMPK pathway to promote amino acid-dependent activation of the mTORC1 complex.

Mary Rose Branch, Cynthia L Hsu, Kohta Ohnishi, Wen-Chuan Shen, Elian Lee, Jill Meisenhelder, Brett Winborn, Bryce L Sopher, J Paul Taylor, Tony Hunter, Albert R La Spada.

mTORC1 is the key rheostat controlling the cellular metabolic state. Of the various inputs to mTORC1, the most potent effector of intracellular nutrient status is amino acid supply. Despite an established role for MAP4K3 in promoting mTORC1 activation in the presence of amino acids, the signaling pathway by which MAP4K3 controls mTORC1 activation remains unknown. Here, we examined the process of MAP4K3 regulation of mTORC1 and found that MAP4K3 represses the LKB1-AMPK pathway to achieve robust mTORC1 activation. When we sought the regulatory link between MAP4K3 and LKB1 inhibition, we discovered that MAP4K3 physically interacts with the master nutrient regulatory factor sirtuin-1 (SIRT1) and phosphorylates SIRT1 to repress LKB1 activation. Our results reveal the existence of a novel signaling pathway linking amino acid satiety with MAP4K3-dependent suppression of SIRT1 to inactivate the repressive LKB1-AMPK pathway and thereby potently activate the mTORC1 complex to dictate the metabolic disposition of the cell.

DOI: https://doi.org/10.26508/lsa.202201525
Cancer Cell. 2023 May 12. pii: S1535-6108(23)00162-9. [Epub ahead of print]

Context-dependent activation of STING-interferon signaling by CD11b agonists enhances anti-tumor immunity.

Xiuting Liu, Graham D Hogg, Chong Zuo, Nicholas C Borcherding, John M Baer, Varintra E Lander, Liang-I Kang, Brett L Knolhoff, Faiz Ahmad, Robin E Osterhout, Anna V Galkin, Jean-Marie Bruey, Laura L Carter, Cedric Mpoy, Kiran R Vij, Ryan C Fields, Julie K Schwarz, Haeseong Park, Vineet Gupta, David G DeNardo.

  Chronic activation of inflammatory pathways and suppressed interferon are hallmarks of immunosuppressive tumors. Previous studies have shown that CD11b integrin agonists could enhance anti-tumor immunity through myeloid reprograming, but the underlying mechanisms remain unclear. Herein we find that CD11b agonists alter tumor-associated macrophage (TAM) phenotypes by repressing NF-κB signaling and activating interferon gene expression simultaneously. Repression of NF-κB signaling involves degradation of p65 protein and is context independent. In contrast, CD11b agonism induces STING/STAT1 pathway-mediated interferon gene expression through FAK-mediated mitochondrial dysfunction, with the magnitude of induction dependent on the tumor microenvironment and amplified by cytotoxic therapies. Using tissues from phase I clinical studies, we demonstrate that GB1275 treatment activates STING and STAT1 signaling in TAMs in human tumors. These findings suggest potential mechanism-based therapeutic strategies for CD11b agonists and identify patient populations more likely to benefit.

Keywords:  CD11b; NF-κB; STING; immunotherapy; pancreatic cancer; tumor-associated macrophages

DOI:  https://doi.org/10.1016/j.ccell.2023.04.018
Cell Rep. 2023 May 18. pii: S2211-1247(23)00541-7. [Epub ahead of print]42(5): 112530

FOXK1 promotes nonalcoholic fatty liver disease by mediating mTORC1-dependent inhibition of hepatic fatty acid oxidation.

Shun Fujinuma, Hirokazu Nakatsumi, Hideyuki Shimizu, Shigeaki Sugiyama, Akihito Harada, Takeshi Goya, Masatake Tanaka, Motoyuki Kohjima, Masatomo Takahashi, Yoshihiro Izumi, Mikako Yagi, Dongchon Kang, Mari Kaneko, Mayo Shigeta, Takeshi Bamba, Yasuyuki Ohkawa, Keiichi I Nakayama.

  Nonalcoholic fatty liver disease (NAFLD) is a chronic metabolic disorder caused by overnutrition and can lead to nonalcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC). The transcription factor Forkhead box K1 (FOXK1) is implicated in regulation of lipid metabolism downstream of mechanistic target of rapamycin complex 1 (mTORC1), but its role in NAFLD-NASH pathogenesis is understudied. Here, we show that FOXK1 mediates nutrient-dependent suppression of lipid catabolism in the liver. Hepatocyte-specific deletion of Foxk1 in mice fed a NASH-inducing diet ameliorates not only hepatic steatosis but also associated inflammation, fibrosis, and tumorigenesis, resulting in improved survival. Genome-wide transcriptomic and chromatin immunoprecipitation analyses identify several lipid metabolism-related genes, including Ppara, as direct targets of FOXK1 in the liver. Our results suggest that FOXK1 plays a key role in the regulation of hepatic lipid metabolism and that its inhibition is a promising therapeutic strategy for NAFLD-NASH, as well as for HCC.

Keywords:  CP: Metabolism; FOXK1; Forkhead box K1; HCC; NAFLD; NASH; conditional knockout mouse; hepatocellular carcinoma; lipid metabolism; mTORC1; mechanistic target of rapamycin complex 1; nonalcoholic fatty liver disease; nonalcoholic steatohepatitis

DOI:  https://doi.org/10.1016/j.celrep.2023.112530
Nat Commun. 2023 May 26. 14(1): 3051

The AE4 transporter mediates kidney acid-base sensing.

H Vitzthum, M Koch, L Eckermann, S L Svendsen, P Berg, C A Hübner, C A Wagner, J Leipziger, C Meyer-Schwesinger, H Ehmke.

The kidney plays a key role in the correction of systemic acid-base imbalances. Central for this regulation are the intercalated cells in the distal nephron, which secrete acid or base into the urine. How these cells sense acid-base disturbances is a long-standing question. Intercalated cells exclusively express the Na+-dependent Cl-/HCO3- exchanger AE4 (Slc4a9). Here we show that AE4-deficient mice exhibit a major dysregulation of acid-base balance. By combining molecular, imaging, biochemical and integrative approaches, we demonstrate that AE4-deficient mice are unable to sense and appropriately correct metabolic alkalosis and acidosis. Mechanistically, a lack of adaptive base secretion via the Cl-/HCO3- exchanger pendrin (Slc26a4) is the key cellular cause of this derailment. Our findings identify AE4 as an essential part of the renal sensing mechanism for changes in acid-base status.

DOI: https://doi.org/10.1038/s41467-023-38562-x
Cell. 2023 May 22. pii: S0092-8674(23)00475-0. [Epub ahead of print]

The enteric nervous system relays psychological stress to intestinal inflammation.

Kai Markus Schneider, Niklas Blank, Yelina Alvarez, Katharina Thum, Patrick Lundgren, Lev Litichevskiy, Madeleine Sleeman, Klaas Bahnsen, Jihee Kim, Simon Kardo, Shaan Patel, Lenka Dohnalová, Giulia T Uhr, Hélène C Descamps, Susanna Kircher, Alana M McSween, Ashkan Rezazadeh Ardabili, Kelsey M Nemec, Monica T Jimenez, Lila G Glotfelty, Joshua D Eisenberg, Emma E Furth, Jorge Henao-Mejia, F Chris Bennett, Marie J Pierik, Mariëlle Romberg-Camps, Zlatan Mujagic, Marco Prinz, Carolin V Schneider, E John Wherry, Meenakshi Bewtra, Robert O Heuckeroth, Maayan Levy, Christoph A Thaiss.

  Mental health profoundly impacts inflammatory responses in the body. This is particularly apparent in inflammatory bowel disease (IBD), in which psychological stress is associated with exacerbated disease flares. Here, we discover a critical role for the enteric nervous system (ENS) in mediating the aggravating effect of chronic stress on intestinal inflammation. We find that chronically elevated levels of glucocorticoids drive the generation of an inflammatory subset of enteric glia that promotes monocyte- and TNF-mediated inflammation via CSF1. Additionally, glucocorticoids cause transcriptional immaturity in enteric neurons, acetylcholine deficiency, and dysmotility via TGF-β2. We verify the connection between the psychological state, intestinal inflammation, and dysmotility in three cohorts of IBD patients. Together, these findings offer a mechanistic explanation for the impact of the brain on peripheral inflammation, define the ENS as a relay between psychological stress and gut inflammation, and suggest that stress management could serve as a valuable component of IBD care.

Keywords:  IBD; enteric glia; enteric nervous system; enteric neurons; glucocorticoids; monocytes; neuro-immune interactions; psychological stress

DOI:  https://doi.org/10.1016/j.cell.2023.05.001
Nature. 2023 May 24.

Tumour extracellular vesicles and particles induce liver metabolic dysfunction.

Gang Wang, Jianlong Li, Linda Bojmar, Haiyan Chen, Zhong Li, Gabriel C Tobias, Mengying Hu, Edwin A Homan, Serena Lucotti, Fengbo Zhao, Valentina Posada, Peter R Oxley, Michele Cioffi, Han Sang Kim, Huajuan Wang, Pernille Lauritzen, Nancy Boudreau, Zhanjun Shi, Christin E Burd, Jonathan H Zippin, James C Lo, Geoffrey S Pitt, Jonathan Hernandez, Constantinos P Zambirinis, Michael A Hollingsworth, Paul M Grandgenett, Maneesh Jain, Surinder K Batra, Dominick J DiMaio, Jean L Grem, Kelsey A Klute, Tanya M Trippett, Mikala Egeblad, Doru Paul, Jacqueline Bromberg, David Kelsen, Vinagolu K Rajasekhar, John H Healey, Irina R Matei, William R Jarnagin, Robert E Schwartz, Haiying Zhang, David Lyden.

Cancer alters the function of multiple organs beyond those targeted by metastasis1,2. Here we show that inflammation, fatty liver and dysregulated metabolism are hallmarks of systemically affected livers in mouse models and in patients with extrahepatic metastasis. We identified tumour-derived extracellular vesicles and particles (EVPs) as crucial mediators of cancer-induced hepatic reprogramming, which could be reversed by reducing tumour EVP secretion via depletion of Rab27a. All EVP subpopulations, exosomes and principally exomeres, could dysregulate hepatic function. The fatty acid cargo of tumour EVPs-particularly palmitic acid-induced secretion of tumour necrosis factor (TNF) by Kupffer cells, generating a pro-inflammatory microenvironment, suppressing fatty acid metabolism and oxidative phosphorylation, and promoting fatty liver formation. Notably, Kupffer cell ablation or TNF blockade markedly decreased tumour-induced fatty liver generation. Tumour implantation or pre-treatment with tumour EVPs diminished cytochrome P450 gene expression and attenuated drug metabolism in a TNF-dependent manner. We also observed fatty liver and decreased cytochrome P450 expression at diagnosis in tumour-free livers of patients with pancreatic cancer who later developed extrahepatic metastasis, highlighting the clinical relevance of our findings. Notably, tumour EVP education enhanced side effects of chemotherapy, including bone marrow suppression and cardiotoxicity, suggesting that metabolic reprogramming of the liver by tumour-derived EVPs may limit chemotherapy tolerance in patients with cancer. Our results reveal how tumour-derived EVPs dysregulate hepatic function and their targetable potential, alongside TNF inhibition, for preventing fatty liver formation and enhancing the efficacy of chemotherapy.

DOI: https://doi.org/10.1038/s41586-023-06114-4
Nat Commun. 2023 May 20. 14(1): 2894

Alanine supplementation exploits glutamine dependency induced by SMARCA4/2-loss.

Xianbing Zhu, Zheng Fu, Shary Y Chen, Dionzie Ong, Giulio Aceto, Rebecca Ho, Jutta Steinberger, Anie Monast, Virginie Pilon, Eunice Li, Monica Ta, Kyle Ching, Bianca N Adams, Gian L Negri, Luc Choiniere, Lili Fu, Kitty Pavlakis, Patrick Pirrotte, Daina Z Avizonis, Jeffrey Trent, Bernard E Weissman, Ramon I Klein Geltink, Gregg B Morin, Morag Park, David G Huntsman, William D Foulkes, Yemin Wang, Sidong Huang.

SMARCA4 (BRG1) and SMARCA2 (BRM) are the two paralogous ATPases of the SWI/SNF chromatin remodeling complexes frequently inactivated in cancers. Cells deficient in either ATPase have been shown to depend on the remaining counterpart for survival. Contrary to this paralog synthetic lethality, concomitant loss of SMARCA4/2 occurs in a subset of cancers associated with very poor outcomes. Here, we uncover that SMARCA4/2-loss represses expression of the glucose transporter GLUT1, causing reduced glucose uptake and glycolysis accompanied with increased dependency on oxidative phosphorylation (OXPHOS); adapting to this, these SMARCA4/2-deficient cells rely on elevated SLC38A2, an amino acid transporter, to increase glutamine import for fueling OXPHOS. Consequently, SMARCA4/2-deficient cells and tumors are highly sensitive to inhibitors targeting OXPHOS or glutamine metabolism. Furthermore, supplementation of alanine, also imported by SLC38A2, restricts glutamine uptake through competition and selectively induces death in SMARCA4/2-deficient cancer cells. At a clinically relevant dose, alanine supplementation synergizes with OXPHOS inhibition or conventional chemotherapy eliciting marked antitumor activity in patient-derived xenografts. Our findings reveal multiple druggable vulnerabilities of SMARCA4/2-loss exploiting a GLUT1/SLC38A2-mediated metabolic shift. Particularly, unlike dietary deprivation approaches, alanine supplementation can be readily applied to current regimens for better treatment of these aggressive cancers.

DOI: https://doi.org/10.1038/s41467-023-38594-3
iScience. 2023 May 19. 26(5): 106717

Alternatively activated lung alveolar and interstitial macrophages promote fungal growth.

Ashley B Strickland, Yanli Chen, Donglei Sun, Meiqing Shi.

  How lung macrophages, especially interstitial macrophages (IMs), respond to invading pathogens remains elusive. Here, we show that mice exhibited a rapid and substantial expansion of macrophages, especially CX3CR1+ IMs, in the lung following infection with Cryptococcus neoformans, a pathogenic fungus leading to high mortality among patients with HIV/AIDS. The IM expansion correlated with enhanced CSF1 and IL-4 production and was affected by the deficiency of CCR2 or Nr4a1. Both alveolar macrophages (AMs) and IMs were observed to harbor C. neoformans and became alternatively activated following infection, with IMs being more polarized. The absence of AMs by genetically disrupting CSF2 signaling reduced fungal loads in the lung and prolonged the survival of infected mice. Likewise, infected mice depleted of IMs by the CSF1 receptor inhibitor PLX5622 displayed significantly lower pulmonary fungal burdens. Thus, C. neoformans infection induces alternative activation of both AMs and IMs, which facilitates fungal growth in the lung.

Keywords:  Biological sciences; Cell biology; Immunology; Mycology

DOI:  https://doi.org/10.1016/j.isci.2023.106717
Cell Rep Med. 2023 May 16. pii: S2666-3791(23)00167-2. [Epub ahead of print] 101053

Tissue-resident memory CAR T cells with stem-like characteristics display enhanced efficacy against solid and liquid tumors.

In-Young Jung, Estela Noguera-Ortega, Robert Bartoszek, Sierra M Collins, Erik Williams, Megan Davis, Julie K Jadlowsky, Gabriela Plesa, Donald L Siegel, Anne Chew, Bruce L Levine, Shelley L Berger, Edmund K Moon, Steven M Albelda, Joseph A Fraietta.

  Chimeric antigen receptor (CAR) T cells demonstrate remarkable success in treating hematological malignancies, but their effectiveness in non-hematopoietic cancers remains limited. This study proposes enhancing CAR T cell function and localization in solid tumors by modifying the epigenome governing tissue-residency adaptation and early memory differentiation. We identify that a key factor in human tissue-resident memory CAR T cell (CAR-TRM) formation is activation in the presence of the pleotropic cytokine, transforming growth factor β (TGF-β), which enforces a core program of both "stemness" and sustained tissue residency by mediating chromatin remodeling and concurrent transcriptional changes. This approach leads to a practical and clinically actionable in vitro production method for engineering peripheral blood T cells into a large number of "stem-like" CAR-TRM cells resistant to tumor-associated dysfunction, possessing an enhanced ability to accumulate in situ and rapidly eliminate cancer cells for more effective immunotherapy.

Keywords:  CAR T-cells3; chimeric antigen receptor; epigenetic modification; hematological malignancies; immunotherapy; memory differentiation; non-hematopoietic cancers; solid tumors; tissue residency; transforming growth factor-β

DOI:  https://doi.org/10.1016/j.xcrm.2023.101053
Front Immunol. 2023 ;14 1168635

The transcriptional control of the VEGFA-VEGFR1 (FLT1) axis in alternatively polarized murine and human macrophages.

Apolka Domokos, Zsofia Varga, Karoly Jambrovics, Noemí Caballero-Sánchez, Eniko Szabo, Gergely Nagy, Beata Scholtz, Laszlo Halasz, Eszter Varadi, Krisztian P Bene, Anett Mazlo, Attila Bacsi, Viktoria Jeney, Gabor J Szebeni, Laszlo Nagy, Zsolt Czimmerer.

  Introduction: Macrophages significantly contribute to the regulation of vessel formation under physiological and pathological conditions. Although the angiogenesis-regulating role of alternatively polarized macrophages is quite controversial, a growing number of evidence shows that they can participate in the later phases of angiogenesis, including vessel sprouting and remodeling or regression. However, the epigenetic and transcriptional regulatory mechanisms controlling this angiogenesis-modulating program are not fully understood.Results: Here we show that IL-4 can coordinately regulate the VEGFA-VEGFR1 (FLT1) axis via simultaneously inhibiting the proangiogenic Vegfa and inducing the antiangiogenic Flt1 expression in murine bone marrow-derived macrophages, which leads to the attenuated proangiogenic activity of alternatively polarized macrophages. The IL-4-activated STAT6 and IL-4-STAT6 signaling pathway-induced EGR2 transcription factors play a direct role in the transcriptional regulation of the Vegfa-Flt1 axis. We demonstrated that this phenomenon is not restricted to the murine bone marrow-derived macrophages, but can also be observed in different murine tissue-resident macrophages ex vivo and parasites-elicited macrophages in vivo with minor cell type-specific differences. Furthermore, IL-4 exposure can modulate the hypoxic response of genes in both murine and human macrophages leading to a blunted Vegfa/VEGFA and synergistically induced Flt1/FLT1 expression.
Discussion: Our findings establish that the IL-4-activated epigenetic and transcriptional program can determine angiogenesis-regulating properties in alternatively polarized macrophages under normoxic and hypoxic conditions.

Keywords:  EGR2; FLT1; IL-4; STAT6; VEGFA; hypoxia; macrophage; transcriptional regulation

DOI:  https://doi.org/10.3389/fimmu.2023.1168635
Immunol Rev. 2023 May 22.

Get me out of here: Sphingosine 1-phosphate signaling and T cell exit from tissues during an immune response.

Victoria M Hallisey, Susan R Schwab.

  During an immune response, the duration of T cell residence in lymphoid and non-lymphoid tissues likely affects T cell activation, differentiation, and memory development. The factors that govern T cell transit through inflamed tissues remain incompletely understood, but one important determinant of T cell exit from tissues is sphingosine 1-phosphate (S1P) signaling. In homeostasis, S1P levels are high in blood and lymph compared to lymphoid organs, and lymphocytes follow S1P gradients out of tissues into circulation using varying combinations of five G-protein coupled S1P receptors. During an immune response, both the shape of S1P gradients and the expression of S1P receptors are dynamically regulated. Here we review what is known, and key questions that remain unanswered, about how S1P signaling is regulated in inflammation and in turn how S1P shapes immune responses.

Keywords:  T cells; cell trafficking; chemokines; lipid mediators; lymph nodes

DOI:  https://doi.org/10.1111/imr.13219
Cell Chem Biol. 2023 May 22. pii: S2451-9456(23)00126-5. [Epub ahead of print]

Small-molecule MHC-II inducers promote immune detection and anti-cancer immunity via editing cancer metabolism.

Ling Huang, Jun Zhang, Bo Wei, Shuangyang Chen, Sitong Zhu, Weiguan Qi, Xiaoying Pei, Lulu Li, Weiguang Liu, Yuzhi Wang, Xiaojun Xu, Lan-Gui Xie, Liming Chen.

  Lack of MHC-II is emerging as a causal factor in cancer immune evasion, and the development of small-molecule MHC-II inducers is an unmet clinical need. Here, we identified three MHC-II inducers, including pristane and its two superior derivatives, that potently induce MHC-II expression in breast cancer cells and effectively inhibit the development of breast cancer. Our data suggest that MHC-II is central in promoting the immune detection of cancer to increase the tumor infiltration of T cells and enhance anti-cancer immunity. By discovering the malonyl/acetyltransferase (MAT) domain in fatty acid synthase (FASN) as the direct binding target of MHC-II inducers, we demonstrate that evasion of immune detection and cancer metabolic reprogramming are directly linked by fatty acid-mediated MHC-II silencing. Collectively, we identified three MHC-II inducers and illustrated that lack of MHC-II caused by hyper-activated fatty acid synthesis to limit immune detection is a potentially widespread mechanism underlying the development of cancer.

Keywords:  MHC-II inducers; cancer immunity; cancer metabolism; immune detection; immunotherapy

DOI:  https://doi.org/10.1016/j.chembiol.2023.05.003
Res Sq. 2023 May 10. pii: rs.3.rs-2838359. [Epub ahead of print]

Pyruvate dehydrogenase complex integrates the metabolome and epigenome in CD8+ memory T cell differentiation in vitro.

Tatiana Tarasenko, Payal Banerjee, Julio Gomez-Rodriguez, Derek Gildea, Suiyuan Zhang, Tyra Wolfsberg, Lisa Jenkins, Nisc Comparative Sequencing Program, Peter McGuire.

Modulation of metabolic flux through pyruvate dehydrogenase complex (PDC) plays an important role in T cell activation and differentiation. PDC sits at the transition between glycolysis and the tricarboxylic acid cycle and is a major producer of acetyl-CoA, marking it as a potential metabolic and epigenetic node. To understand the role of pyruvate dehydrogenase complex in T cell differentiation, we generated mice deficient in T cell pyruvate dehydrogenase E1A ( Pdha ) subunit using a CD4-cre recombinase-based strategy. Herein, we show that genetic ablation of PDC activity in T cells ( TPdh -/- ) leads to marked perturbations in glycolysis, the tricarboxylic acid cycle, and OXPHOS. TPdh -/- T cells became dependent upon substrate level phosphorylation via glycolysis, secondary to depressed OXPHOS. Due to the block of PDC activity, histone acetylation was also reduced, including H3K27, a critical site for CD8 + T M differentiation. Transcriptional and functional profiling revealed abnormal CD8 + T M differentiation in vitro. Collectively, our data indicate that PDC integrates the metabolome and epigenome in CD8 + memory T cell differentiation. Targeting this metabolic and epigenetic node can have widespread ramifications on cellular function.

DOI: https://doi.org/10.21203/rs.3.rs-2838359/v1
Cell Rep. 2023 May 23. pii: S2211-1247(23)00561-2. [Epub ahead of print]42(6): 112550

Depletion of CUL4B in macrophages ameliorates diabetic kidney disease via miR-194-5p/ITGA9 axis.

Shiqi Jin, Yu Song, Li Zhou, Wei Jiang, Liping Qin, Yufeng Wang, Ruiqi Yu, Yuting Liu, Yujie Diao, Fan Zhang, Kaixuan Liu, Peishan Li, Huili Hu, Baichun Jiang, Wei Tang, Fan Yi, Yaoqin Gong, Guangyi Liu, Gongping Sun.

  Diabetic kidney disease (DKD) is the most prevalent chronic kidney disease. Macrophage infiltration in the kidney is critical for the progression of DKD. However, the underlying mechanism is far from clear. Cullin 4B (CUL4B) is the scaffold protein in CUL4B-RING E3 ligase complexes. Previous studies have shown that depletion of CUL4B in macrophages aggravates lipopolysaccharide-induced peritonitis and septic shock. In this study, using two mouse models for DKD, we demonstrate that myeloid deficiency of CUL4B alleviates diabetes-induced renal injury and fibrosis. In vivo and in vitro analyses reveal that loss of CUL4B suppresses migration, adhesion, and renal infiltration of macrophages. Mechanistically, we show that high glucose upregulates CUL4B in macrophages. CUL4B represses expression of miR-194-5p, which leads to elevated integrin α9 (ITGA9), promoting migration and adhesion. Our study suggests the CUL4B/miR-194-5p/ITGA9 axis as an important regulator for macrophage infiltration in diabetic kidneys.

Keywords:  CP: Immunology; CUL4B; ITGA9; diabetic kidney disease; macrophage infiltration; miR-194-5p

DOI:  https://doi.org/10.1016/j.celrep.2023.112550
Nat Commun. 2023 May 23. 14(1): 2978

Genetically encoded photocatalytic protein labeling enables spatially-resolved profiling of intracellular proteome.

Fu Zheng, Xinyue Zhou, Peng Zou, Chenxin Yu.

Mapping the subcellular organization of proteins is crucial for understanding their biological functions. Herein, we report a reactive oxygen species induced protein labeling and identification (RinID) method for profiling subcellular proteome in the context of living cells. Our method capitalizes on a genetically encoded photocatalyst, miniSOG, to locally generate singlet oxygen that reacts with proximal proteins. Labeled proteins are conjugated in situ with an exogenously supplied nucleophilic probe, which serves as a functional handle for subsequent affinity enrichment and mass spectrometry-based protein identification. From a panel of nucleophilic compounds, we identify biotin-conjugated aniline and propargyl amine as highly reactive probes. As a demonstration of the spatial specificity and depth of coverage in mammalian cells, we apply RinID in the mitochondrial matrix, capturing 477 mitochondrial proteins with 94% specificity. We further demonstrate the broad applicability of RinID in various subcellular compartments, including the nucleus and the endoplasmic reticulum (ER). The temporal control of RinID enables pulse-chase labeling of ER proteome in HeLa cells, which reveals substantially higher clearance rate for secreted proteins than ER resident proteins.

DOI: https://doi.org/10.1038/s41467-023-38565-8
Nature. 2023 May 24.

γ-Linolenic acid in maternal milk drives cardiac metabolic maturation.

Ana Paredes, Raquel Justo-Méndez, Daniel Jiménez-Blasco, Vanessa Núñez, Irene Calero, María Villalba-Orero, Andrea Alegre-Martí, Thierry Fischer, Ana Gradillas, Viviane Aparecida Rodrigues Sant'Anna, Felipe Were, Zhiqiang Huang, Pablo Hernansanz-Agustín, Carmen Contreras, Fernando Martínez, Emilio Camafeita, Jesús Vázquez, Jesús Ruiz-Cabello, Estela Area-Gómez, Fátima Sánchez-Cabo, Eckardt Treuter, Juan Pedro Bolaños, Eva Estébanez-Perpiñá, Francisco Javier Rupérez, Coral Barbas, José Antonio Enríquez, Mercedes Ricote.

Birth presents a metabolic challenge to cardiomyocytes as they reshape fuel preference from glucose to fatty acids for postnatal energy production1,2. This adaptation is triggered in part by post-partum environmental changes3, but the molecules orchestrating cardiomyocyte maturation remain unknown. Here we show that this transition is coordinated by maternally supplied γ-linolenic acid (GLA), an 18:3 omega-6 fatty acid enriched in the maternal milk. GLA binds and activates retinoid X receptors4 (RXRs), ligand-regulated transcription factors that are expressed in cardiomyocytes from embryonic stages. Multifaceted genome-wide analysis revealed that the lack of RXR in embryonic cardiomyocytes caused an aberrant chromatin landscape that prevented the induction of an RXR-dependent gene expression signature controlling mitochondrial fatty acid homeostasis. The ensuing defective metabolic transition featured blunted mitochondrial lipid-derived energy production and enhanced glucose consumption, leading to perinatal cardiac dysfunction and death. Finally, GLA supplementation induced RXR-dependent expression of the mitochondrial fatty acid homeostasis signature in cardiomyocytes, both in vitro and in vivo. Thus, our study identifies the GLA-RXR axis as a key transcriptional regulatory mechanism underlying the maternal control of perinatal cardiac metabolism.

DOI: https://doi.org/10.1038/s41586-023-06068-7
Sci Adv. 2023 May 26. 9(21): eade7280

Nitric oxide synthase and reduced arterial tone contribute to arteriovenous malformation.

Lawrence Huang, Feng Cheng, Xuetao Zhang, Jacek Zielonka, Matthew A Nystoriak, Weiwei Xiang, Kunal Raygor, Shaoxun Wang, Aditya Lakshmanan, Weiya Jiang, Sai Yuan, Kevin S Hou, Jiayi Zhang, Xitao Wang, Arsalan U Syed, Matea Juric, Takamune Takahashi, Manuel F Navedo, Rong A Wang.

Mechanisms underlying arteriovenous malformations (AVMs) are poorly understood. Using mice with endothelial cell (EC) expression of constitutively active Notch4 (Notch4*EC), we show decreased arteriolar tone in vivo during brain AVM initiation. Reduced vascular tone is a primary effect of Notch4*EC, as isolated pial arteries from asymptomatic mice exhibited reduced pressure-induced arterial tone ex vivo. The nitric oxide (NO) synthase (NOS) inhibitor NG-nitro-l-arginine (L-NNA) corrected vascular tone defects in both assays. L-NNA treatment or endothelial NOS (eNOS) gene deletion, either globally or specifically in ECs, attenuated AVM initiation, assessed by decreased AVM diameter and delayed time to moribund. Administering nitroxide antioxidant 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl also attenuated AVM initiation. Increased NOS-dependent production of hydrogen peroxide, but not NO, superoxide, or peroxynitrite was detected in isolated Notch4*EC brain vessels during AVM initiation. Our data suggest that eNOS is involved in Notch4*EC-mediated AVM formation by up-regulating hydrogen peroxide and reducing vascular tone, thereby permitting AVM initiation and progression.

DOI: https://doi.org/10.1126/sciadv.ade7280