bims-traimu 2024-05-19 papers

bims-traimu

Biomed News

on Trained immunity

Issue of 2024‒05‒19
eighteen papers selected by
Yantong Wan, Southern Medical University

Oroxylin A-induced Trained Immunity Promotes LC3-associated Phagocytosis in Macrophage in Protecting Mice Against Sepsis.
Endotoxin tolerance and trained immunity: breaking down immunological memory barriers.
Editorial: Myeloid cell reprogramming: molecular pathways involved in disease development.
Cholesterol accumulation impairs HIF-1α-dependent immunometabolic reprogramming of LPS-stimulated macrophages by upregulating the NRF2 pathway.
Factors Affecting Neutrophil Functions During Sepsis: Human Microbiome and Epigenetics.
Reversal of high-glucose-induced transcriptional and epigenetic memories through NRF2 pathway activation.
Octyl itaconate enhances VSVΔ51 oncolytic virotherapy by multitarget inhibition of antiviral and inflammatory pathways.
Neutrophil-macrophage communication via extracellular vesicle transfer promotes itaconate accumulation and ameliorates cytokine storm syndrome.
Low-molecular weight branched polyethylenimine reduces cytokine secretion from human immune system monocytes stimulated with bacterial and fungal PAMPs.
Histone H3 posttranslational modified enzymes defined neutrophil plasticity and their vulnerability to IL-10 in the course of the inflammation.
GITR exacerbates lysophosphatidylcholine-induced macrophage pyroptosis in sepsis via posttranslational regulation of NLRP3.
The emerging roles of glutamine amidotransferases in metabolism and immune defense.
Current advances and future trends of hormesis in disease.
CD5L as a promising biological therapeutic for treating sepsis.
Protecting effects of 4-octyl itaconate on neonatal hypoxic-ischemic encephalopathy via Nrf2 pathway in astrocytes.
Temporal Changes in Innate and Adaptive Immunity During Sepsis as Determined by ELISpot.
Monocyte bioenergetics: An immunometabolic perspective in metabolic dysfunction-associated steatohepatitis.
Astrocytes remember inflammation.

Inflammation. 2024 May 13.

Oroxylin A-induced Trained Immunity Promotes LC3-associated Phagocytosis in Macrophage in Protecting Mice Against Sepsis.

Lijie Yin, Ziqian Bing, Yaojun Zheng, Yuchen Pan, Yue Dong, Jiali Wang, Renjie Luo, Yue Zhao, Huan Dou, Yayi Hou.

  Sepsis is defined as a dysregulated host response to infection that leads to multiorgan failure. Innate immune memory, i.e., "trained immunity", can result in stronger immune responses and provide protection against various infections. Many biological agents, including β-glucan, can induce trained immunity, but these stimuli may cause uncontrolled inflammation. Oroxylin A (OA) is an active flavonoid compound that is derived from Scutellaria baicalensis. OA is an agonist for inducing trained immunity in vivo and in vitro, and β-glucan was used as a positive control. The protective effects of OA-induced trained immunity were evaluated in mouse models that were established by either lipopolysaccharide (LPS) administration or caecal ligation and puncture (CLP). The expression of inflammatory factors and signaling pathway components involved in trained immunity was evaluated in vitro using qRT‒PCR, western blotting (WB) and enzyme-linked immunosorbent assay (ELISA). Flow cytometry and confocal microscopy were used to examine reactive oxygen species (ROS) levels and phagocytosis in trained macrophages. A PCR array was used to screen genes that were differentially expressed in trained macrophages. Here, we revealed that OA alleviated sepsis via trained immunity. OA-treated macrophages displayed increased glycolysis and mTOR phosphorylation, and mTOR inhibitors suppressed OA-induced trained immunity by effectively reprogramming macrophages. The PCR array revealed key genes in the mTOR signaling pathway in OA-treated macrophages. Furthermore, OA targeted the Dectin-1-syk axis to promote LC3-associated phagocytosis (LAP) by trained macrophages, thereby enhancing the ability of these macrophages to protect against infection. This ability could be transferred to a new host via the adoptive transfer of peritoneal macrophages. This study is the first to provide new insights into the potential of OA-induced trained immunity to be used as a strategy to protect mice against sepsis by promoting LAP by macrophages.

Keywords:  LC3-associated phagocytosis; macrophage; oroxylin A; sepsis; trained immunity

DOI:  https://doi.org/10.1007/s10753-024-02033-2
Front Immunol. 2024 ;15 1393283

Endotoxin tolerance and trained immunity: breaking down immunological memory barriers.

Eduardo López-Collazo, Carlos Del Fresno.

  For decades, innate immune cells were considered unsophisticated first responders, lacking the adaptive memory of their T and B cell counterparts. However, mounting evidence demonstrates the surprising complexity of innate immunity. Beyond quickly deploying specialized cells and initiating inflammation, two fascinating phenomena - endotoxin tolerance (ET) and trained immunity (TI) - have emerged. ET, characterized by reduced inflammatory response upon repeated exposure, protects against excessive inflammation. Conversely, TI leads to an enhanced response after initial priming, allowing the innate system to mount stronger defences against subsequent challenges. Although seemingly distinct, these phenomena may share underlying mechanisms and functional implications, blurring the lines between them. This review will delve into ET and TI, dissecting their similarities, differences, and the remaining questions that warrant further investigation.

Keywords:  endotoxin tolerance; innate immune memory; macrophage; monocyte; trained immunity

DOI:  https://doi.org/10.3389/fimmu.2024.1393283
Front Immunol. 2024 ;15 1414482

Editorial: Myeloid cell reprogramming: molecular pathways involved in disease development.

Denise Risnik, Ana Colado, Enrique Podaza.



Keywords:  MDSC (myeloid-derived suppressor cell); macrophages; myeloid cell reprogramming; myeloid cells; trained immunity

DOI:  https://doi.org/10.3389/fimmu.2024.1414482
Sci Rep. 2024 05 15. 14(1): 11162

Cholesterol accumulation impairs HIF-1α-dependent immunometabolic reprogramming of LPS-stimulated macrophages by upregulating the NRF2 pathway.

Kenneth K Y Ting, Pei Yu, Riley Dow, Hisham Ibrahim, Saraf Karim, Chanele K Polenz, Daniel A Winer, Minna Woo, Jenny Jongstra-Bilen, Myron I Cybulsky.

Lipid accumulation in macrophages (Mφs) is a hallmark of atherosclerosis. Yet, how lipid loading modulates Mφ inflammatory responses remains unclear. We endeavored to gain mechanistic insights into how pre-loading with free cholesterol modulates Mφ metabolism upon LPS-induced TLR4 signaling. We found that activities of prolyl hydroxylases (PHDs) and factor inhibiting HIF (FIH) are higher in cholesterol loaded Mφs post-LPS stimulation, resulting in impaired HIF-1α stability, transactivation capacity and glycolysis. In RAW264.7 cells expressing mutated HIF-1α proteins resistant to PHDs and FIH activities, cholesterol loading failed to suppress HIF-1α function. Cholesterol accumulation induced oxidative stress that enhanced NRF2 protein stability and triggered a NRF2-mediated antioxidative response prior to and in conjunction with LPS stimulation. LPS stimulation increased NRF2 mRNA and protein expression, but it did not enhance NRF2 protein stability further. NRF2 deficiency in Mφs alleviated the inhibitory effects of cholesterol loading on HIF-1α function. Mutated KEAP1 proteins defective in redox sensing expressed in RAW264.7 cells partially reversed the effects of cholesterol loading on NRF2 activation. Collectively, we showed that cholesterol accumulation in Mφs induces oxidative stress and NRF2 stabilization, which when combined with LPS-induced NRF2 expression leads to enhanced NRF2-mediated transcription that ultimately impairs HIF-1α-dependent glycolytic and inflammatory responses.

DOI: https://doi.org/10.1038/s41598-024-61493-6
J Leukoc Biol. 2024 May 12. pii: qiae107. [Epub ahead of print]

Factors Affecting Neutrophil Functions During Sepsis: Human Microbiome and Epigenetics.

Yina Ma, Yu Zhao, Xin Zhang.

  Sepsis is a severe disease that occurs when the body's immune system reacts excessively to infection. The body's response, which includes an intense anti-bacterial reaction, can damage its tissues and organs. Neutrophils are the major components of white blood cells in circulation and play a vital role in innate immunity while fighting against infections, and are considered a feature determining sepsis classification. There's a plethora of basic research detailing neutrophil functioning, among which, the study of neutrophil extracellular traps (NETs) is providing novel insights into mechanisms and treatments of sepsis. This review explores their functions, dysfunctions, and influences in the context of sepsis. The interplay between neutrophils and the human microbiome and the impact of DNA methylation on neutrophil function in sepsis are crucial areas of study. The interaction between neutrophils and the human microbiome is complex, particularly in the context of sepsis where dysbiosis may occur. We highlight the importance of deciphering neutrophil's functional alterations and their epigenetic features in sepsis because it is critical for defining sepsis endotypes and opening up the possibility for novel diagnostic methods and therapy. Specifically, epigenetic signatures are pivotal since they will provide a novel implication for sepsis diagnostic method when used in combination with the cell-free DNA (cfDNA). Research is exploring how specific patterns of DNA methylation in neutrophils, detectable in cfDNA, could serve as biomarkers for the early detection of sepsis.

Keywords:  cfDNA; epigenetics; gut microbiome; neutrophil; trained immunity

DOI:  https://doi.org/10.1093/jleuko/qiae107
Life Sci Alliance. 2024 Aug;pii: e202302382. [Epub ahead of print]7(8):

Reversal of high-glucose-induced transcriptional and epigenetic memories through NRF2 pathway activation.

Martí Wilson-Verdugo, Brandon Bustos-García, Olga Adame-Guerrero, Jaqueline Hersch-González, Nallely Cano-Domínguez, Maribel Soto-Nava, Carlos A Acosta, Teresa Tusie-Luna, Santiago Avila-Rios, Lilia G Noriega, Victor J Valdes.

Diabetes complications such as nephropathy, retinopathy, or cardiovascular disease arise from vascular dysfunction. In this context, it has been observed that past hyperglycemic events can induce long-lasting alterations, a phenomenon termed "metabolic memory." In this study, we evaluated the genome-wide gene expression and chromatin accessibility alterations caused by transient high-glucose exposure in human endothelial cells (ECs) in vitro. We found that cells exposed to high glucose exhibited substantial gene expression changes in pathways known to be impaired in diabetes, many of which persist after glucose normalization. Chromatin accessibility analysis also revealed that transient hyperglycemia induces persistent alterations, mainly in non-promoter regions identified as enhancers with neighboring genes showing lasting alterations. Notably, activation of the NRF2 pathway through NRF2 overexpression or supplementation with the plant-derived compound sulforaphane, effectively reverses the glucose-induced transcriptional and chromatin accessibility memories in ECs. These findings underscore the enduring impact of transient hyperglycemia on ECs' transcriptomic and chromatin accessibility profiles, emphasizing the potential utility of pharmacological NRF2 pathway activation in mitigating and reversing the high-glucose-induced transcriptional and epigenetic alterations.

DOI: https://doi.org/10.26508/lsa.202302382
Nat Commun. 2024 May 15. 15(1): 4096

Octyl itaconate enhances VSVΔ51 oncolytic virotherapy by multitarget inhibition of antiviral and inflammatory pathways.

Naziia Kurmasheva, Aida Said, Boaz Wong, Priscilla Kinderman, Xiaoying Han, Anna H F Rahimic, Alena Kress, Madalina E Carter-Timofte, Emilia Holm, Demi van der Horst, Christoph F Kollmann, Zhenlong Liu, Chen Wang, Huy-Dung Hoang, Elina Kovalenko, Maria Chrysopoulou, Krishna Sundar Twayana, Rasmus N Ottosen, Esben B Svenningsen, Fabio Begnini, Anders E Kiib, Florian E H Kromm, Hauke J Weiss, Daniele Di Carlo, Michela Muscolini, Maureen Higgins, Mirte van der Heijden, Angelina Bardoul, Tong Tong, Attila Ozsvar, Wen-Hsien Hou, Vivien R Schack, Christian K Holm, Yunan Zheng, Melanie Ruzek, Joanna Kalucka, Laureano de la Vega, Walid A M Elgaher, Anders R Korshoej, Rongtuan Lin, John Hiscott, Thomas B Poulsen, Luke A O'Neill, Dominic G Roy, Markus M Rinschen, Nadine van Montfoort, Jean-Simon Diallo, Henner F Farin, Tommy Alain, David Olagnier.

The presence of heterogeneity in responses to oncolytic virotherapy poses a barrier to clinical effectiveness, as resistance to this treatment can occur through the inhibition of viral spread within the tumor, potentially leading to treatment failures. Here we show that 4-octyl itaconate (4-OI), a chemical derivative of the Krebs cycle-derived metabolite itaconate, enhances oncolytic virotherapy with VSVΔ51 in various models including human and murine resistant cancer cell lines, three-dimensional (3D) patient-derived colon tumoroids and organotypic brain tumor slices. Furthermore, 4-OI in combination with VSVΔ51 improves therapeutic outcomes in a resistant murine colon tumor model. Mechanistically, we find that 4-OI suppresses antiviral immunity in cancer cells through the modification of cysteine residues in MAVS and IKKβ independently of the NRF2/KEAP1 axis. We propose that the combination of a metabolite-derived drug with an oncolytic virus agent can greatly improve anticancer therapeutic outcomes by direct interference with the type I IFN and NF-κB-mediated antiviral responses.

DOI: https://doi.org/10.1038/s41467-024-48422-x
Cell Mol Immunol. 2024 May 14.

Neutrophil-macrophage communication via extracellular vesicle transfer promotes itaconate accumulation and ameliorates cytokine storm syndrome.

Haixia Kang, Ting Liu, Yuanyuan Wang, Wenjuan Bai, Yan Luo, Jing Wang.

  Cytokine storm syndrome (CSS) is a life-threatening systemic inflammatory syndrome involving innate immune hyperactivity triggered by various therapies, infections, and autoimmune conditions. However, the potential interplay between innate immune cells is not fully understood. Here, using poly I:C and lipopolysaccharide (LPS)-induced cytokine storm models, a protective role of neutrophils through the modulation of macrophage activation was identified in a CSS model. Intravital imaging revealed neutrophil-derived extracellular vesicles (NDEVs) in the liver and spleen, which were captured by macrophages. NDEVs suppressed proinflammatory cytokine production by macrophages when cocultured in vitro or infused into CSS models. Metabolic profiling of macrophages treated with NDEV revealed elevated levels of the anti-inflammatory metabolite, itaconate, which is produced from cis-aconitate in the Krebs cycle by cis-aconitate decarboxylase (Acod1, encoded by Irg1). Irg1 in macrophages, but not in neutrophils, was critical for the NDEV-mediated anti-inflammatory effects. Mechanistically, NDEVs delivered miR-27a-3p, which suppressed the expression of Suclg1, the gene encoding the enzyme that metabolizes itaconate, thereby resulting in the accumulation of itaconate in macrophages. These findings demonstrated that neutrophil-to-macrophage communication mediated by extracellular vesicles is critical for promoting the anti-inflammatory reprogramming of macrophages in CSS and may have potential implications for the treatment of this fatal condition.

Keywords:  Cytokine storm syndrome; Extracellular vesicle; Itaconate; Macrophage; Neutrophil

DOI:  https://doi.org/10.1038/s41423-024-01174-6
ChemMedChem. 2024 May 13. e202400011

Low-molecular weight branched polyethylenimine reduces cytokine secretion from human immune system monocytes stimulated with bacterial and fungal PAMPs.

Neda Heydarian, Maya Ferrell, Ayesha S Nair, Chase Roedl, Zongkai Peng, Tra D Nguyen, William Best, Karen L Wozniak, Charles Rice.

  Adaptive immunity recruits T-cells and specific antibodies against antigens, innate immune cells express pathogen recognition receptors (PRRs) that can detect various pathogen-associated molecular patterns (PAMPs) released by invading pathogens. Microbial molecular patterns, such as lipopolysaccharide (LPS) from Gram-negative bacteria, trigger signaling cascades in the host that result in the production of pro-inflammatory cytokines. LPS stimulation produces a strong immune response and excessive LPS signaling leads to dysregulation of the immune response. However, dysregulated inflammatory response during wound healing often results in chronic non-healing wounds that are difficult to control. In this work, we present data demonstrating partial neutralization of anionic LPS molecules using cationic branched polyethylenimine (BPEI). The anionic sites on the LPS molecules from Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) are the lipid A moiety and BPEI binding create steric factors that hinder the binding of PRR signaling co-factors. This reduces the production of pro-inflammatory TNF-α cytokines. However, the anionic sites of Pseudomonas aeruginosa (P. aeruginosa) LPS are in the O-antigen region and subsequent BPEI binding slightly reduces TNF-α cytokine production. Fortunately, BPEI can reduce TNF-α cytokine expression in response to stimulation by intact P. aeruginosa bacterial cells and fungal zymosan PAMPs.

Keywords:  branched polyethylenimine; cytokine; lipopolysaccharide; pathogen-associated molecular pattern molecules

DOI:  https://doi.org/10.1002/cmdc.202400011
J Inflamm (Lond). 2024 May 14. 21(1): 16

Histone H3 posttranslational modified enzymes defined neutrophil plasticity and their vulnerability to IL-10 in the course of the inflammation.

Paweł Piatek, Magdalena Namiecinska, Natalia Lewkowicz, Małgorzata Kulińska-Michalska, Zbigniew Jabłonowski, Mariola Matysiak, Sylwia Michlewska, Marek Wieczorek, Przemysław Lewkowicz.

  BACKGROUND: Neutrophils are a heterogeneous population capable of antimicrobial functions associated with pre-activation/activation and tissue regeneration. The specific polarisation of immune cells is mediated by the modification of 'chromatin landscapes', which enables differentiated access and activity of regulatory elements that guarantee their plasticity during inflammation No specific pattern within histone posttranslational modifications (PTMs) controlling this plasticity has been identified.METHODS: Using the in vitro model of inflammation, reflecting different states of neutrophils from resting, pre-activated cells to activated and reducing tissue regeneration, we have analysed 11 different histone posttranslational modifications (PTMs), PTM enzymes associated with remodelling neutrophil chromatin, and H3K4me3 ChIP-Seq Gene Ontology analysis focusing on the processes related to histone PTMs. These findings were verified by extrapolation to adequate clinical status, using neutrophils derived from the patients with sepsis (systemic septic inflammation with LPS-stimulated neutrophils), neuromyelitis optical spectrum disorders (aseptic inflammation with pre-activated neutrophils) and periodontitis (local self-limiting septic inflammation with IL-10-positive neutrophils).
RESULTS: Physiological activation of neutrophils comprises a pre-activation characterised by histone H3K27ac and H3K4me1, which position enhancers; direct LPS exposure is induced explicitly by H3K4me3 which marked Transcription Start Site (TSS) regions and low-level of H3K9me3, H3K79me2 and H3K27me3 which, in turn, marked repressed genes. Contrary to antimicrobial action, IL-10 positively induced levels of H3S10p and negatively H3K9me3, which characterised processes related to the activation of genes within heterochromatin mediated by CHD1 and H3K9me3 specific demethylase JMJD2A. IL-10 protects changes within histone PTMs induced by TNF or LPS that affected H3K4me3-specific methyltransferase SETD1A and MLL1. Neutrophils previously exposed to inflammatory factors become unvulnerable to IL-10 because previous LPS stimulation interrupts TSS regions marked by H3K4me3 of CHD1 and JMJD2A genes. Therefore, LPS-activated neutrophils are disabled to induce CHD1/JMJD2A enzymes by IL-10, making this process irreversible. Because transcription of JMJD2A and CHD1 also depends on TSS positioning by H3K4me3, neutrophils before LPS stimulation become insensitive to IL-10.
CONCLUSION: Neutrophils, once pre-activated by TNF or directly stimulated by LPS, become insensitive to the anti-inflammatory effects of IL-10, and vice versa; IL-10 protects neutrophils against these proinflammatory stimuli. This phenomenon is responsible for disturbing the natural process of resolving inflammation and tissue regeneration.

Keywords:  H3K4me3-marked histone; Neuromyelitis Optica Spectrum disorders; Neutrophils; Periodontitis; Posttranslational histone modification; Sepsis

DOI:  https://doi.org/10.1186/s12950-024-00389-8
Cell Mol Immunol. 2024 May 13.

GITR exacerbates lysophosphatidylcholine-induced macrophage pyroptosis in sepsis via posttranslational regulation of NLRP3.

Siping Liang, Jinyu Zhou, Can Cao, Yiting Liu, Siqi Ming, Xi Liu, Yuqi Shang, Juanfeng Lao, Qin Peng, Jiahui Yang, Minhao Wu.

  The NLRP3 inflammasome functions as an inflammatory driver, but its relationship with lipid metabolic changes in early sepsis remains unclear. Here, we found that GITR expression in monocytes/macrophages was induced by lysophosphatidylcholine (LPC) and was positively correlated with the severity of sepsis. GITR is a costimulatory molecule that is mainly expressed on T cells, but its function in macrophages is largely unknown. Our in vitro data showed that GITR enhanced LPC uptake by macrophages and specifically enhanced NLRP3 inflammasome-mediated macrophage pyroptosis. Furthermore, in vivo studies using either cecal ligation and puncture (CLP) or LPS-induced sepsis models demonstrated that LPC exacerbated sepsis severity/lethality, while conditional knockout of GITR in myeloid cells or NLRP3/caspase-1/IL-1β deficiency attenuated sepsis severity/lethality. Mechanistically, GITR specifically enhanced inflammasome activation by regulating the posttranslational modification (PTM) of NLRP3. GITR competes with NLRP3 for binding to the E3 ligase MARCH7 and recruits MARCH7 to induce deacetylase SIRT2 degradation, leading to decreasing ubiquitination but increasing acetylation of NLRP3. Overall, these findings revealed a novel role of macrophage-derived GITR in regulating the PTM of NLRP3 and systemic inflammatory injury, suggesting that GITR may be a potential therapeutic target for sepsis and other inflammatory diseases. GITR exacerbates LPC-induced macrophage pyroptosis in sepsis via posttranslational regulation of NLRP3. According to the model, LPC levels increase during the early stage of sepsis, inducing GITR expression on macrophages. GITR not only competes with NLRP3 for binding to the E3 ligase MARCH7 but also recruits MARCH7 to induce the degradation of the deacetylase SIRT2, leading to decreasing ubiquitination but increasing acetylation of NLRP3 and therefore exacerbating LPC-induced NLRP3 inflammasome activation, macrophage pyroptosis and systemic inflammatory injury.

Keywords:  GITR; Macrophage; NLRP3 inflammasome; Posttranslational modification; Sepsis

DOI:  https://doi.org/10.1038/s41423-024-01170-w
Nucleosides Nucleotides Nucleic Acids. 2024 May 14. 1-15

The emerging roles of glutamine amidotransferases in metabolism and immune defense.

Taolin Xie, Chao Qin, Ali Can Savas, Wayne Wei Yeh, Pinghui Feng.

  Glutamine amidotransferases (GATs) catalyze the synthesis of nucleotides, amino acids, glycoproteins and an enzyme cofactor, thus serving as key metabolic enzymes for cell proliferation. Carbamoyl-phosphate synthetase, Aspartate transcarbamoylase, and Dihydroorotase (CAD) is a multifunctional enzyme of the GAT family and catalyzes the first three steps of the de novo pyrimidine synthesis. Following our findings that cellular GATs are involved in immune evasion during herpesvirus infection, we discovered that CAD reprograms cellular metabolism to fuel aerobic glycolysis and nucleotide synthesis via deamidating RelA. Deamidated RelA activates the expression of key glycolytic enzymes, rather than that of the inflammatory NF-κB-responsive genes. As such, cancer cells prime RelA for deamidation via up-regulating CAD activity or accumulating RelA mutations. Interestingly, the recently emerged SARS-CoV-2 also activates CAD to couple evasion of inflammatory response to activated nucleotide synthesis. A small molecule inhibitor of CAD depletes nucleotide supply and boosts antiviral inflammatory response, thus greatly reducing SARS-CoV-2 replication. Additionally, we also found that CTP synthase 1 (CTPS1) deamidates interferon (IFN) regulatory factor 3 (IRF3) to mute IFN induction. Our previous studies have implicated phosphoribosyl formylglycinamidine synthase (PFAS) and phosphoribosyl pyrophosphate amidotransferase (PPAT) in deamidating retinoic acid-inducible gene I (RIG-I) and evading dsRNA-induced innate immune defense in herpesvirus infection. Overall, these studies have uncovered an unconventional enzymatic activity of cellular GATs in metabolism and immune defense, offering a molecular link intimately coupling these fundamental biological processes.

Keywords:  Glutamine amidotransferase; innate immunity; nucleotide synthesis; protein deamidation; tumor metabolism; viral infection

DOI:  https://doi.org/10.1080/15257770.2024.2351135
NPJ Aging. 2024 May 15. 10(1): 26

Current advances and future trends of hormesis in disease.

Yantong Wan, Jinxi Liu, Yiyin Mai, Yinghao Hong, Zixuan Jia, Guijie Tian, Yunzhuo Liu, Huaping Liang, Jinghua Liu.

Hormesis, an adaptive response, occurs when exposure to low doses of a stressor potentially induces a stimulatory effect, while higher doses may inhibit it. This phenomenon is widely observed across various organisms and stressors, significantly advancing our understanding and inspiring further exploration of the beneficial effects of toxins at doses both below and beyond traditional thresholds. This has profound implications for promoting biological regulation at the cellular level and enhancing adaptability throughout the biosphere. Therefore, conducting bibliometric analysis in this field is crucial for accurately analyzing and summarizing its current research status. The results of the bibliometric analysis reveal a steady increase in the number of publications in this field over the years. The United States emerges as the leading country in both publication and citation numbers, with the journal Dose-Response publishing the highest number of papers in this area. Calabrese E.J. is a prominent person with significant contributions and influence among authors. Through keyword co-occurrence and trend analysis, current hotspots in this field are identified, primarily focusing on the relationship between hormesis, oxidative stress, and aging. Analysis of highly cited references predicts that future research trends may center around the relationship between hormesis and stress at different doses, as well as exploring the mechanisms and applications of hormesis. In conclusion, this review aims to visually represent hormesis-related research through bibliometric methods, uncovering emerging patterns and areas of focus within the field. It provides a summary of the current research status and forecasts trends in hormesis-related research.

DOI: https://doi.org/10.1038/s41514-024-00155-3
Nat Commun. 2024 May 15. 15(1): 4119

CD5L as a promising biological therapeutic for treating sepsis.

Liliana Oliveira, M Carolina Silva, Ana P Gomes, Rita F Santos, Marcos S Cardoso, Ana Nóvoa, Hervé Luche, Bruno Cavadas, Irina Amorim, Fátima Gärtner, Bernard Malissen, Moisés Mallo, Alexandre M Carmo.

Sepsis results from systemic, dysregulated inflammatory responses to infection, culminating in multiple organ failure. Here, we demonstrate the utility of CD5L for treating experimental sepsis caused by cecal ligation and puncture (CLP). We show that CD5L's important features include its ability to enhance neutrophil recruitment and activation by increasing circulating levels of CXCL1, and to promote neutrophil phagocytosis. CD5L-deficient mice exhibit impaired neutrophil recruitment and compromised bacterial control, rendering them susceptible to attenuated CLP. CD5L-/- peritoneal cells from mice subjected to medium-grade CLP exhibit a heightened pro-inflammatory transcriptional profile, reflecting a loss of control of the immune response to the infection. Intravenous administration of recombinant CD5L (rCD5L) in immunocompetent C57BL/6 wild-type (WT) mice significantly ameliorates measures of disease in the setting of high-grade CLP-induced sepsis. Furthermore, rCD5L lowers endotoxin and damage-associated molecular pattern (DAMP) levels, and protects WT mice from LPS-induced endotoxic shock. These findings warrant the investigation of rCD5L as a possible treatment for sepsis in humans.

DOI: https://doi.org/10.1038/s41467-024-48360-8
J Neuroinflammation. 2024 May 17. 21(1): 132

Protecting effects of 4-octyl itaconate on neonatal hypoxic-ischemic encephalopathy via Nrf2 pathway in astrocytes.

Yanping Yang, Yang Li, Wenyi Yang, Xueying Yang, Man Luo, Ling Qin, Junchao Zhu.

  BACKGROUND: Neonatal hypoxic-ischemic encephalopathy (HIE) is one of the most common neurological problems occurring in the perinatal period. However, there still is not a promising approach to reduce long-term neurodevelopmental outcomes of HIE. Recently, itaconate has been found to exhibit anti-oxidative and anti-inflammatory effects. However, the therapeutic efficacy of itaconate in HIE remains inconclusive. Therefore, this study attempts to explore the pathophysiological mechanisms of oxidative stress and inflammatory responses in HIE as well as the potential therapeutic role of a derivative of itaconate, 4-octyl itaconate (4OI).METHODS: We used 7-day-old mice to induce hypoxic-ischemic (HI) model by right common carotid artery ligation followed by 1 h of hypoxia. Behavioral experiments including the Y-maze and novel object recognition test were performed on HI mice at P60 to evaluate long-term neurodevelopmental outcomes. We employed an approach combining non-targeted metabolomics with transcriptomics to screen alterations in metabolic profiles and gene expression in the hippocampal tissue of the mice at 8 h after hypoxia. Immunofluorescence staining and RT-PCR were used to evaluate the pathological changes in brain tissue cells and the expression of mRNA and proteins. 4OI was intraperitoneally injected into HI model mice to assess its anti-inflammatory and antioxidant effects. BV2 and C8D1A cells were cultured in vitro to study the effect of 4OI on the expression and nuclear translocation of Nrf2. We also used Nrf2-siRNA to further validate 4OI-induced Nrf2 pathway in astrocytes.
RESULTS: We found that in the acute phase of HI, there was an accumulation of pyruvate and lactate in the hippocampal tissue, accompanied by oxidative stress and pro-inflammatory, as well as increased expression of antioxidative stress and anti-inflammatory genes. Treatment of 4OI could inhibit activation and proliferation of microglial cells and astrocytes, reduce neuronal death and relieve cognitive dysfunction in HI mice. Furthermore, 4OI enhanced nuclear factor erythroid-2-related factor (Nfe2l2; Nrf2) expression and nuclear translocation in astrocytes, reduced pro-inflammatory cytokine production, and increased antioxidant enzyme expression.
CONCLUSION: Our study demonstrates that 4OI has a potential therapeutic effect on neuronal damage and cognitive deficits in HIE, potentially through the modulation of inflammation and oxidative stress pathways by Nrf2 in astrocytes.

Keywords:  Astrocyte; Cognitive dysfunction; Hypoxia–ischemia; Itaconate; Nrf2

DOI:  https://doi.org/10.1186/s12974-024-03121-8
Shock. 2024 May 03.

Temporal Changes in Innate and Adaptive Immunity During Sepsis as Determined by ELISpot.

Jacqueline Unsinger, Dale Osborne, Andrew H Walton, Ethan Han, Lauren Sheets, Monty B Mazer, Kenneth E Remy, Thomas S Griffith, Mahil Rao, Vladimir P Badovinac, Scott C Brackenridge, Isaiah Turnbull, Philip A Efron, Lyle L Moldawer, Charles C Caldwell, Richard S Hotchkiss.

BACKGROUND: The inability to evaluate host immunity in a rapid quantitative manner in patients with sepsis has severely hampered development of novel immune therapies. The ELISpot assay is a functional bioassay that measures the number of cytokine-secreting cells and the relative amount of cytokine produced at the single-cell level. A key advantage of ELISpot is its excellent dynamic range enabling a more precise quantifiable assessment of host immunity. Herein, we tested the hypothesis that the ELISpot assay can detect dynamic changes in both innate and adaptive immunity as they often occur during sepsis. We also tested whether ELISpot could detect the effect of immune drug therapies to modulate innate and adaptive immunity.METHODS: Mice were made septic using sublethal cecal ligation and puncture (CLP). Blood and spleens were harvested serially and ex vivo IFN-γ and TNF-α production were compared by ELISpot and ELISA. The capability of ELISpot to detect changes in innate and adaptive immunity due to in vivo immune therapy with dexamethasone, IL-7, and arginine was also evaluated.
RESULTS: ELISpot confirmed a decreased innate and adaptive immunity responsiveness during sepsis progression. More importantly, ELISpot was also able to detect changes in adaptive and innate immunity in response to immune-modulatory reagents, for example dexamethasone, arginine, and IL-7 in a readily quantifiable manner, as predicted by the reagents known mechanisms of action. ELISpot and ELISA results tended to parallel one another although some differences were noted.
CONCLUSION: ELISpot offers a unique capability to assess the functional status of both adaptive and innate immunity over time. The results presented herein demonstrate that ELISpot can also be used to detect and follow the in vivo effects of drugs to ameliorate sepsis-induced immune dysfunction. This capability would be a major advance in guiding new immune therapies in sepsis.

DOI: https://doi.org/10.1097/SHK.0000000000002377
Cell Rep Med. 2024 May 07. pii: S2666-3791(24)00256-8. [Epub ahead of print] 101564

Monocyte bioenergetics: An immunometabolic perspective in metabolic dysfunction-associated steatohepatitis.

Moris Sangineto, Martina Ciarnelli, Tommaso Colangelo, Archana Moola, Vidyasagar Naik Bukke, Loren Duda, Rosanna Villani, Antonino Romano, Stefania Giandomenico, Hina Kanwal, Gaetano Serviddio.

  Monocytes (Mos) are crucial in the evolution of metabolic dysfunction-associated steatotic liver disease (MASLD) to metabolic dysfunction-associated steatohepatitis (MASH), and immunometabolism studies have recently suggested targeting leukocyte bioenergetics in inflammatory diseases. Here, we reveal a peculiar bioenergetic phenotype in circulating Mos of patients with MASH, characterized by high levels of glycolysis and mitochondrial (mt) respiration. The enhancement of mt respiratory chain activity, especially complex II (succinate dehydrogenase [SDH]), is unbalanced toward the production of reactive oxygen species (ROS) and is sustained at the transcriptional level with the involvement of the AMPK-mTOR-PGC-1α axis. The modulation of mt activity with dimethyl malonate (DMM), an SDH inhibitor, restores the metabolic profile and almost abrogates cytokine production. Analysis of a public single-cell RNA sequencing (scRNA-seq) dataset confirms that in murine models of MASH, liver Mo-derived macrophages exhibit an upregulation of mt and glycolytic energy pathways. Accordingly, the DMM injection in MASH mice contrasts Mo infiltration and macrophagic enrichment, suggesting immunometabolism as a potential target in MASH.

Keywords:  MASH; MASLD; NASH; dimethyl malonate; immunometabolism; macrophage; mitochondria; monocyte; obesity; steatosis

DOI:  https://doi.org/10.1016/j.xcrm.2024.101564
Immunity. 2024 May 14. pii: S1074-7613(24)00210-3. [Epub ahead of print]57(5): 938-940

Astrocytes remember inflammation.

Michael R Williamson, Benjamin Deneen.

Astrocytes respond to all forms of central nervous system maladies. In a recent issue of Nature, Lee et al. demonstrate that astrocytes encode inflammatory stimuli as epigenetic memory, which strengthens responses to subsequent stimuli and exacerbates pathology in disease models.

DOI: https://doi.org/10.1016/j.immuni.2024.04.005