bims-cesemi 2024-05-05 papers

bims-cesemi

Biomed News

on Cellular senescence and mitochondria

Issue of 2024–05–05
eight papers selected by
Julio Cesar Cardenas, Universidad Mayor

A pipeline for senolytics.
MCU genetically altered mice suggest how mitochondrial Ca2+ regulates metabolism.
Mitochondrial transfer mediates endothelial cell engraftment through mitophagy.
Iron retardation in lysosome protects senescent cells from ferroptosis.
Senescent CAFs Mediate Immunosuppression and Drive Breast Cancer Progression.
Cannabinoids and healthy ageing: the potential for extending healthspan and lifespan in preclinical models with an emphasis on Caenorhabditis elegans.
Intermittent glucocorticoid treatment improves muscle metabolism via the PGC1α/Lipin1 axis in an aging-related sarcopenia model.
Mitochondria and Cancer.

J Clin Invest. 2024 May 01. pii: e180558. [Epub ahead of print]134(9):

A pipeline for senolytics.

Sundeep Khosla.

There is intense interest in identifying compounds that selectively kill senescent cells, termed senolytics, for ameliorating age-related comorbidities. However, screening for senolytic compounds currently relies on primary cells or cell lines where senescence is induced in vitro. Given the complexity of senescent cells across tissues and diseases, this approach may not target the senescent cells that develop under specific conditions in vivo. In this issue of the JCI, Lee et al. describe a pipeline for high-throughput drug screening of senolytic compounds where senescence was induced in vivo and identify the HSP90 inhibitor XL888 as a candidate senolytic to treat idiopathic pulmonary fibrosis.

DOI: https://doi.org/10.1172/JCI180558
Trends Endocrinol Metab. 2024 Apr 29. pii: S1043-2760(24)00088-2. [Epub ahead of print]

MCU genetically altered mice suggest how mitochondrial Ca2+ regulates metabolism.

Jiuzhou Huo, Jeffery D Molkentin.

  Skeletal muscle has a major impact on total body metabolism and obesity, and is characterized by dynamic regulation of substrate utilization. While it is accepted that acute increases in mitochondrial matrix Ca2+ increase carbohydrate usage to augment ATP production, recent studies in mice with deleted genes for components of the mitochondrial Ca2+ uniporter (MCU) complex have suggested a more complicated regulatory scenario. Indeed, mice with a deleted Mcu gene in muscle, which lack acute mitochondrial Ca2+ uptake, have greater fatty acid oxidation (FAO) and less adiposity. By contrast, mice deleted for the inhibitory Mcub gene in skeletal muscle, which have greater acute mitochondrial Ca2+ uptake, antithetically display reduced FAO and progressive obesity. In this review we discuss the emerging concept that dynamic fluxing of mitochondrial matrix Ca2+ regulates metabolism.

Keywords:  Ca(2+) signaling; metabolism; mitochondria; obesity; skeletal muscle

DOI:  https://doi.org/10.1016/j.tem.2024.04.005
Nature. 2024 May 01.

Mitochondrial transfer mediates endothelial cell engraftment through mitophagy.

Ruei-Zeng Lin, Gwang-Bum Im, Allen Chilun Luo, Yonglin Zhu, Xuechong Hong, Joseph Neumeyer, Hong-Wen Tang, Norbert Perrimon, Juan M Melero-Martin.

Ischaemic diseases such as critical limb ischaemia and myocardial infarction affect millions of people worldwide1. Transplanting endothelial cells (ECs) is a promising therapy in vascular medicine, but engrafting ECs typically necessitates co-transplanting perivascular supporting cells such as mesenchymal stromal cells (MSCs), which makes clinical implementation complicated2,3. The mechanisms that enable MSCs to facilitate EC engraftment remain elusive. Here we show that, under cellular stress, MSCs transfer mitochondria to ECs through tunnelling nanotubes, and that blocking this transfer impairs EC engraftment. We devised a strategy to artificially transplant mitochondria, transiently enhancing EC bioenergetics and enabling them to form functional vessels in ischaemic tissues without the support of MSCs. Notably, exogenous mitochondria did not integrate into the endogenous EC mitochondrial pool, but triggered mitophagy after internalization. Transplanted mitochondria co-localized with autophagosomes, and ablation of the PINK1-Parkin pathway negated the enhanced engraftment ability of ECs. Our findings reveal a mechanism that underlies the effects of mitochondrial transfer between mesenchymal and endothelial cells, and offer potential for a new approach for vascular cell therapy.

DOI: https://doi.org/10.1038/s41586-024-07340-0
Aging (Albany NY). 2024 Apr 26. 16

Iron retardation in lysosome protects senescent cells from ferroptosis.

Yujing Feng, Huaiqing Wei, Meng Lyu, Zhiyuan Yu, Jia Chen, Xinxing Lyu, Fengfeng Zhuang.

  Ferroptosis, an iron-triggered modality of cellular death, has been reported to closely relate to human aging progression and aging-related diseases. However, the involvement of ferroptosis in the development and maintenance of senescent cells still remains elusive. Here, we established a doxorubicin-induced senescent HSkM cell model and found that both iron accumulation and lipid peroxidation increase in senescent cells. Moreover, such iron overload in senescent cells has changed the expression panel of the ferroptosis-response proteins. Interestingly, the iron accumulation and lipid peroxidation does not trigger ferroptosis-induced cell death. Oppositely, senescent cells manifest resistance to the ferroptosis inducers, compared to the proliferating cells. To further investigate the mechanism of ferroptosis-resistance for senescent cells, we traced the iron flux in cell and found iron arrested in lysosome. Moreover, disruption of lysosome functions by chloroquine and LLOMe dramatically triggered the senescent cell death. Besides, the ferroitinophagy-related proteins FTH1/FTL and NCOA4 knockdown also increases the senescent cell death. Thus, we speculated that iron retardation in lysosome of senescent cells is the key mechanism for ferroptosis resistance. And the lysosome is a promising target for senolytic drugs to selectively clear senescent cells and alleviate the aging related diseases.

Keywords:  ferritinophagy; ferroptosis; iron accumulation; lysosome; senescent cells

DOI:  https://doi.org/10.18632/aging.205777
Cancer Discov. 2024 Apr 17. OF1-OF22

Senescent CAFs Mediate Immunosuppression and Drive Breast Cancer Progression.

Jiayu Ye, John M Baer, Douglas V Faget, Vasilios A Morikis, Qihao Ren, Anupama Melam, Ana Paula Delgado, Xianmin Luo, Satarupa Mullick Bagchi, Jad I Belle, Edward Campos, Michael Friedman, Deborah J Veis, Erik S Knudsen, Agnieszka K Witkiewicz, Scott Powers, Gregory D Longmore, David G DeNardo, Sheila A Stewart.

The tumor microenvironment (TME) profoundly influences tumorigenesis, with gene expression in the breast TME capable of predicting clinical outcomes. The TME is complex and includes distinct cancer-associated fibroblast (CAF) subtypes whose contribution to tumorigenesis remains unclear. Here, we identify a subset of myofibroblast CAFs (myCAF) that are senescent (senCAF) in mouse and human breast tumors. Utilizing the MMTV-PyMT;INK-ATTAC (INK) mouse model, we found that senCAF-secreted extracellular matrix specifically limits natural killer (NK) cell cytotoxicity to promote tumor growth. Genetic or pharmacologic senCAF elimination unleashes NK cell killing, restricting tumor growth. Finally, we show that senCAFs are present in HER2+, ER+, and triple-negative breast cancer and in ductal carcinoma in situ (DCIS) where they predict tumor recurrence. Together, these findings demonstrate that senCAFs are potently tumor promoting and raise the possibility that targeting them by senolytic therapy could restrain breast cancer development.
SIGNIFICANCE: senCAFs limit NK cell-mediated killing, thereby contributing to breast cancer progression. Thus, targeting senCAFs could be a clinically viable approach to limit tumor progression.

DOI: https://doi.org/10.1158/2159-8290.CD-23-0426
Geroscience. 2024 May 02.

Cannabinoids and healthy ageing: the potential for extending healthspan and lifespan in preclinical models with an emphasis on Caenorhabditis elegans.

Zhizhen Wang, Jonathon C Arnold.

  There is a significant global upsurge in the number and proportion of older persons in the population. With this comes an increasing prevalence of age-related conditions which pose a major challenge to healthcare systems. The development of anti-ageing treatments may help meet this challenge by targeting the ageing process which is a common denominator to many health problems. Cannabis-like compounds (cannabinoids) are reported to improve quality of life and general well-being in human trials, and there is increasing preclinical research highlighting that they have anti-ageing activity. Moreover, preclinical evidence suggests that endogenous cannabinoids regulate ageing processes. Here, we review the anti-ageing effects of the cannabinoids in various model systems, including the most extensively studied nematode model, Caenorhabditis elegans. These studies highlight that the cannabinoids lengthen healthspan and lifespan, with emerging evidence that they may also hinder the development of cellular senescence. The non-psychoactive cannabinoid cannabidiol (CBD) shows particular promise, with mechanistic studies demonstrating it may work through autophagy induction and activation of antioxidative systems. Furthermore, CBD improves healthspan parameters such as diminishing age-related behavioural dysfunction in models of both healthy and accelerated ageing. Translation into mammalian systems provides an important next step. Moreover, looking beyond CBD, future studies could probe the multitude of other cannabis constituents for their anti-ageing activity.

Keywords:   C. elegans,; Cannabidiol,; Endocannabinoid system; Health span,; Lifespan,

DOI:  https://doi.org/10.1007/s11357-024-01162-8
J Clin Invest. 2024 May 03. pii: e177427. [Epub ahead of print]

Intermittent glucocorticoid treatment improves muscle metabolism via the PGC1α/Lipin1 axis in an aging-related sarcopenia model.

Ashok Daniel Prabakaran, Kevin McFarland, Karen Miz, Hima Bindu Durumutla, Kevin Piczer, Fadoua El Abdellaoui-Soussi, Hannah Latimer, Cole Werbrich, Hyun-Jy Chung, N Scott Blair, Douglas P Millay, Andrew J Morris, Brendan Prideaux, Brian N Finck, Mattia Quattrocelli.

  Sarcopenia burdens the elderly population through loss of muscle energy and mass, yet treatments to functionally rescue both parameters are missing. The glucocorticoid prednisone remodels muscle metabolism based on frequency of intake, but its mechanisms in sarcopenia are unknown. We found that once-weekly intermittent prednisone rescued muscle quality in aged 24-month-old mice to levels comparable to young 4-month-old mice. We discovered an age- and sex-independent glucocorticoid receptor transactivation program in muscle encompassing PGC1α and its co-factor Lipin1. Treatment coordinately improved mitochondrial abundance through isoform 1 and muscle mass through isoform 4 of the myocyte-specific PGC1α, which was required for the treatment-driven increase in carbon shuttling from glucose to amino acid biogenesis. We also probed the myocyte-specific Lipin1 as non-redundant factor coaxing PGC1α upregulation to the stimulation of both oxidative and anabolic effects. Our study unveils an aging-resistant druggable program in myocytes to coordinately rescue energy and mass in sarcopenia.

Keywords:  Aging; Epigenetics; Mitochondria; Muscle; Muscle biology

DOI:  https://doi.org/10.1172/JCI177427
Cold Spring Harb Perspect Med. 2024 May 01. pii: a041534. [Epub ahead of print]

Mitochondria and Cancer.

Timothy C Kenny, Kıvanç Birsoy.

Mitochondria are semiautonomous organelles with diverse metabolic and cellular functions including anabolism and energy production through oxidative phosphorylation. Following the pioneering observations of Otto Warburg nearly a century ago, an immense body of work has examined the role of mitochondria in cancer pathogenesis and progression. Here, we summarize the current state of the field, which has coalesced around the position that functional mitochondria are required for cancer cell proliferation. In this review, we discuss how mitochondria influence tumorigenesis by impacting anabolism, intracellular signaling, and the tumor microenvironment. Consistent with their critical functions in tumor formation, mitochondria have become an attractive target for cancer therapy. We provide a comprehensive update on the numerous therapeutic modalities targeting the mitochondria of cancer cells making their way through clinical trials.

DOI: https://doi.org/10.1101/cshperspect.a041534