Proteomic analysis of the role of chaperone-mediated autophagy (CMA) in muscle stem cells (MuSCs) regenerative functions
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ABSTRACT:
INSTRUMENT(S):
ORGANISM(S): Mus Musculus (mouse)
TISSUE(S): Skeletal Muscle Myoblast, Cell Culture
SUBMITTER: 
Ignacio Ramírez Pardo
LAB HEAD: Ignacio Ramírez Pardo
PROVIDER: PXD069565 | Pride | 2025-10-17
REPOSITORIES: Pride
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Project description:The activity of brown fat, a tissue mediating non-shivering thermogenesis, is associated with protection against obesity, diabetes, and cardiovascular disease. In response to thermogenic stimuli, brown adipose tissue (BAT) increases its activity through extensive cellular and tissue plasticity. While macroautophagy is typically inhibited during BAT thermogenic activation, we found that chaperone-mediated autophagy (CMA), a selective type of autophagy, is instead induced. CMA induction enhances both basal and cAMP-stimulated activity of brown adipocytes, as evidenced by increased expression of thermogenesis-related genes, enhanced release of brown adipokines, elevated cellular oxidative activity, and increased lipolysis. In aging, when BAT activity declines, LAMP2A—the limiting CMA component—is downregulated in BAT. However, pharmacological activation of CMA restores BAT activity in aged mice. To investigate the consequences of this CMA failure in BAT, we generated brown adipocytes knock down for LAMP2A and using comparative proteomics identified that CMA regulates levels of proteins involved in BAT thermogenic and metabolic activity. We demonstrate that selective CMA blockade in interscapular BAT in mice leads to reduced energy expenditure, increased triglyceridemia, lower expression of thermogenic markers and BAT-secretory functions, and to accumulation of thermogenesis repressors upon thermogenic activation. Overall, these findings support the essential role of CMA in BAT function and adaptation to thermogenic activation. CMA facilitates the timely degradation of thermogenic repressors, thereby promoting adaptive enhancement of thermogenic activity.
2025-09-30 | PXD062807 | Pride
Project description:Proteostasis supports stemness and its loss correlates with the functional decline of diverse stem cell types. Here we identify that chaperone-mediated autophagy (CMA), a selective autophagy pathway, is necessary for the regenerative capacity of muscle stem cells (MuSCs) throughout life. We show that CMA is active in MuSCs, while genetic loss of CMA in MuSCs or failure of CMA in normally aged cells causes a proliferative impairment, resulting in defective skeletal muscle regeneration. Reactivation of CMA in old MuSCs boosts their proliferative capacity and improves their regenerative ability. Using comparative proteomics to identify CMA substrates, we uncovered actin cytoskeleton and glycolytic metabolism as key processes altered in aged mice and human MuSCs. Our findings reveal CMA to be a decisive stem-cell-fate regulator, with implications for fostering muscle regeneration in old age.
2025-10-15 | GSE286877 | GEO
Project description:Proteostasis supports stemness and its loss correlates with the functional decline of diverse stem cell types. Here we identify that chaperone-mediated autophagy (CMA), a selective autophagy pathway, is necessary for the regenerative capacity of muscle stem cells (MuSCs) throughout life. We show that CMA is active in MuSCs, while genetic loss of CMA in MuSCs or failure of CMA in normally aged cells causes a proliferative impairment, resulting in defective skeletal muscle regeneration. Reactivation of CMA in old MuSCs boosts their proliferative capacity and improves their regenerative ability. Using comparative proteomics to identify CMA substrates, we uncovered actin cytoskeleton and glycolytic metabolism as key processes altered in aged mice and human MuSCs. Our findings reveal CMA to be a decisive stem-cell-fate regulator, with implications for fostering muscle regeneration in old age.
2025-10-17 | PXD059966 | Pride
Project description:Chaperone-mediated autophagy (CMA), a selective autophagic process, plays a crucial role in maintaining intracellular quality and facilitating cellular responses to stress. While CMA has been implicated in finely regulating the stemness of normal stem cells, its significance in cancer stem cells (CSCs) remains largely undefined. In this study, we demonstrate that CMA is upregulated in patient-derived glioblastoma stem cells (GSCs), characterized by a notable increase in the levels of the CMA receptor, lysosome-associated membrane protein type 2A (LAMP2A). The enhanced stability of LAMP2A within GSC lysosomes is a result of MST4-mediated phosphorylation at residues T40, S97, and T136, which facilitates LAMP2A homotrimer formation and diminishes LAMP2A degradation by obstructing the interaction between LAMP2A and Cathepsin A. The contribution of CMA to the self-renewal and tumorigenic potential of GSCs is mediated by the upregulation of mTORC1 activity through the selective lysosomal degradation of its two negative modulators, TSC1 and TSC2. Furthermore, CMA is implicated in promoting resistance to immunotherapy in GBM by inhibiting the TET3-dependent enhancement of tumor cGAS and STING expression. Finally, the genetic or pharmacological inhibition of CMA exhibits a synergistic effect with immune checkpoint therapy in murine models of GBM. Our findings delineate an MST4-LAMP2A signaling pathway that modulates CMA activity and the malignancy of GSCs, with therapeutic targeting of this axis potentially overcoming immunotherapy resistance in GBM.
2025-09-22 | PXD060464 | Pride
Project description:The role of autophagy and metabolism in regulating the pluripotency of stem cells is not well understood. LAMP2A is a key gene in CMA. Here we compared transcriptomic changes in LAMP2A-overexpressed D3 versus control cells, as well as changes in LAMP2A-overexpressed cells with versus without DM-αKG treatment (4mM, 72 hrs). We found that overexpression of LAMP2A leads to decreased expression of genes related to stem cell differentiation, and this can be largely restored by DM-αKG supplement. This study provides a promising link for autophagy, metabolism, and pluripotency of stem cells.
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Project description:Background and aim: The molecular mechanisms underlying the progression of nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH) remain unclear; however, the role of autophagy in these mechanisms has attracted extensive attention. This study aimed to investigate the role of chaperone-mediated autophagy (CMA) in NAFL-to-NASH progression and elucidate the underlying mechanisms. Methods: Hepatic CMA activity was analyzed in patients with NASH and mouse models of NASH. LAMP2A was knocked down or overexpressed to assess the effects of hepatocyte-specific CMA on NAFL-to-NASH progression. Mice were fed a high-fat diet or a methionine–choline-deficient diet to induce NAFL or NASH. Palmitic acid was used to mimic lipotoxicity-induced hepatocyte damage in vitro. The promoter activity of FOXM1 was evaluated via chromatin immunoprecipitation and dual-luciferase reporter assay. Results: Hepatic CMA activity was substantially low in patients and mice with NASH. Knockdown of LAMP2A resulted in hepatocyte-specific CMA deficiency, which promoted hepatic inflammation and fibrosis in mice with NASH. In addition, CMA deficiency exacerbated endoplasmic reticulum (ER) stress and hepatocyte damage in vivo and in vitro. Mechanistically, CMA deficiency in hepatocytes increased cholesterol accumulation by blocking the degradation of HMGCR, a rate-limiting enzyme of cholesterol synthesis, and the accumulated cholesterol subsequently induced ER stress and hepatocyte damage. Restoration of hepatocyte-specific CMA activity effectively ameliorated diet-induced NASH and ER stress in vivo and in vitro. FOXM1 negatively regulated the transcription of LAMP2A by directly binding to its promoter. Upregulation of FOXM1 impaired CMA and enhanced ER stress, which in turn increased FOXM1 expression, resulting in a vicious circle and promoting the development of NASH. Conclusions: This study highlights the role of the FOXM1/CMA/ER stress axis in NAFL-to-NASH progression and proposes novel therapeutic targets for NASH.
2025-02-19 | GSE274949 | GEO
Project description:Chaperone-mediated autophagy (CMA) is a homeostatic process essential for the lysosomal degradation of individual proteins. CMA activity directly depends on the levels of LAMP2A, critical receptor at the lysosomal membrane, to which CMA substrate proteins are bound. In glioblastoma (GBM), the most common and aggressive brain cancer in the adulthood, high levels of LAMP2A have been linked to TMZ resistance and tumor-associated pericytes. However, the implication of LAMP2A, and hence CMA, in glioblastoma stem cells (GSCs) remains unknown. In this work, we show that LAMP2A expression is enriched in patient-derived GSC population and its knock-down diminishes GSCs tumorigenic activities. Proteomic and transcriptomic analysis of LAMP2A knocked-down GSCs revealed reduced extracellular matrix (ECM) interaction effectors in both analyses. Moreover, immune system and mitochondrial metabolism related pathways were remarkably deregulated at proteome level, whereas PI3K-AKT and p53 pathways were altered in RNAseq study. Moreover, clinical samples of GBM tissue presented overexpression of LAMP2 and its high levels correlated with advanced glioma grade and poor overall survival. In conclusion, we identified a novel role of CMA directly regulating GSCs activity via multiple pathways at proteome and transcriptome level.
2023-03-11 | PXD027069 | Pride
Project description:Chaperone-mediated autophagy (CMA) is a homeostatic process essential for the lysosomal degradation of individual proteins. CMA activity directly depends on the levels of LAMP2A, critical receptor at the lysosomal membrane, to which CMA substrate proteins are bound. In glioblastoma (GBM), the most common and aggressive brain cancer in the adulthood, high levels of LAMP2A have been linked to TMZ resistance and tumor-associated pericytes. However, the implication of LAMP2A, and hence CMA, in glioblastoma stem cells (GSCs) remains unknown. In this work, we show that LAMP2A expression is enriched in patient-derived GSC population and its knock-down diminishes GSCs tumorigenic activities. Proteomic and transcriptomic analysis of LAMP2A knocked-down GSCs revealed reduced extracellular matrix (ECM) interaction effectors in both analyses. Moreover, immune system and mitochondrial metabolism related pathways were remarkably deregulated at proteome level, whereas PI3K-AKT and p53 pathways were altered in RNAseq study. Moreover, clinical samples of GBM tissue presented overexpression of LAMP2 and its high levels correlated with advanced glioma grade and poor overall survival. In conclusion, we identified a novel role of CMA directly regulating GSCs activity via multiple pathways at proteome and transcriptome level.
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Project description:The most common genetic risk factors for Parkinson’s disease (PD) are a set of heterozygous mutant (MT) alleles of the GBA1 gene that encodes -glucocerebrosidase (GCase), an enzyme that is normally trafficked from the endoplasmic reticulum and Golgi apparatus to the lysosomal lumen. We examined isolated lysosomes from anterior cingulate cortex, a region of high alpha-synuclein accumulation in GBA-PD, and found that while lysosomal GCase is entirely luminal in healthy controls, half of the lysosomal GBA-PD GCase was present on the lysosomal surface. This lysosomal mislocalization is dependent on a pentapeptide motif in GCase used for targeting of cytosolic proteins to lysosomes for degradation by chaperone-mediated autophagy (CMA), a type of autophagy inhibited by PD-related pathogenic proteins including -synuclein and LRRK2. Single cell transcriptional analysis and comparative proteomics of brains from GBA-PD patients demonstrated reduced CMA activity and overall proteome changes similar to those observed in mouse models with CMA blockage. We found that the delivery of unfolded mutant GCase to lysosomes decreased CMA due to recognition of unfolded mutant GCase to the chaperone hsc70, and the resulting complex binds the CMA receptor LAMP2A at the lysosomal surface. Unfolded mutant GCase is a poor substrate for translocation into the lysosomal lumen, and by interfering with LAMP2A multimerization, blocks the translocation and causes cytosolic accumulation of other CMA substrates including -synuclein and tau. In primary substantia nigra dopamine neurons, MT GCase led to neuronal death, while loss of the GCase CMA motif or deletion of -synuclein rescued the neurons. These results indicate how MT GCase alleles may converge with other PD proteins to block CMA function and produce -synuclein accumulation.
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