Project description:Skeletal muscle wasting is a devastating consequence of cancer that affects up to 80% of cancer patients and associates with reduced survival. Herein we identified the transcriptional repressor protein, Forkhead box P1 (FoxP1), as a downstream target gene of FoxO1 whose skeletal muscle expression is elevated in multiple models of cancer cachexia and in patients with cancer who exhibit cachexia. Through generation of inducible skeletal muscle-specific FoxP1 over-expressing (FoxP1iSkmTg/Tg) mice, we demonstrate that FoxP1 upregulation is sufficient to induce features of cachexia, including body and skeletal muscle wasting characterized by reduced muscle fiber cross-sectional area of type IIX/B muscle fibers. Muscles from FoxP1iSkmTg/Tg mice also showed significant muscle damage and myopathy characterized by the accumulation of p62 and cellular material-filled vesicles, the presence of centrally nucleated myofibers, and were significantly weaker than controls. In the context of cancer cachexia, blocking FoxP1 upregulation prevented the cancer-induced repression of target genes critical to muscle structural integrity and repair, including Myocyte enhancer factor 2c (Mef2c), improved muscle ultrastructure and significantly attenuated muscle fiber atrophy. We further show that the muscle wasting phenotype induced by FoxP1 required the activity of histone deacetylase (HDAC) proteins, which are well-established to cooperate with FoxP1 to mediate gene repression, and which were necessary for FoxP1-dependent repression of Mef2c. In summary, we identify FoxP1 as a negative transcriptional regulator of skeletal muscle mass and function, whose up-regulation mediates cancer-induced muscle wasting. We used microarrays to investigate the genome-wide transcriptional networks regulated by the FoxO1 and FoxP1 transcription factors in skeletal muscle of tumor-bearing mice.
Project description:Cancer cachexia is a debilitating metabolic disorder characterized by involuntary loss of body and muscle mass, leading to increased morbidity and mortality. We previously found that Forkhead box P1 (FoxP1) upregulation in skeletal muscle causes muscle wasting and is required for muscle wasting in response to cancer. However, transcriptional networks targeted by FoxP1 in skeletal muscles undergoing cancer-induced wasting remain largely unknown. Here, we identify FoxP1 as a key disruptor of the skeletal muscle clock in response to cancer, that reprograms circadian patterns of gene expression at cachexia onset. Specifically, we show that cancer-induced FoxP1 rewires the skeletal muscle circadian transcriptome towards pathways associated with muscle wasting and disrupts the temporal patterning of pathways governing glucose, lipid, and oxidative metabolism. These findings thus implicate cancer/disease-specific functions of FOXP1 in the disruption and reprograming of the skeletal muscle circadian transcriptome which may contribute to muscle wasting and the development of cachexia.
Project description:Cancer cachexia is a debilitating metabolic disorder characterized by involuntary loss of body and muscle mass, leading to increased morbidity and mortality. We previously found that Forkhead box P1 (FoxP1) upregulation in skeletal muscle causes muscle wasting and is required for muscle wasting in response to cancer. However, transcriptional networks targeted by FoxP1 in skeletal muscles undergoing cancer-induced wasting remain largely unknown. Here, we identify FoxP1 as a key disruptor of the skeletal muscle clock in response to cancer, that reprograms circadian patterns of gene expression at cachexia onset. Specifically, we show that cancer-induced FoxP1 rewires the skeletal muscle circadian transcriptome towards pathways associated with muscle wasting and disrupts the temporal patterning of pathways governing glucose, lipid, and oxidative metabolism. These findings thus implicate cancer/disease-specific functions of FOXP1 in the disruption and reprograming of the skeletal muscle circadian transcriptome which may contribute to muscle wasting and the development of cachexia.
Project description:Cancer cachexia is a debilitating metabolic disorder characterized by involuntary loss of body and muscle mass, leading to increased morbidity and mortality. We previously found that Forkhead box P1 (FoxP1) upregulation in skeletal muscle causes muscle wasting and is required for muscle wasting in response to cancer. However, transcriptional networks targeted by FoxP1 in skeletal muscles undergoing cancer-induced wasting remain largely unknown. Here, we identify FoxP1 as a key disruptor of the skeletal muscle clock in response to cancer, that reprograms circadian patterns of gene expression at cachexia onset. Specifically, we show that cancer-induced FoxP1 rewires the skeletal muscle circadian transcriptome towards pathways associated with muscle wasting and disrupts the temporal patterning of pathways governing glucose, lipid, and oxidative metabolism. These findings thus implicate cancer/disease-specific functions of FOXP1 in the disruption and reprograming of the skeletal muscle circadian transcriptome which may contribute to muscle wasting and the development of cachexia.
Project description:Skeletal muscle wasting is commonly associated with chronic kidney disease (CKD), resulting in increased morbidity and mortality. However, the link between kidney and muscle function remains poorly understood. Here, we took a complementary interorgan approach to investigate skeletal muscle wasting in CKD. We identified an increased production and elevated blood levels of soluble pro-cachectic factor Activin A, directly linking experimental and human CKD to skeletal muscle wasting programs. Systemic pharmacological blockade of Activin A using soluble activin receptor type IIB ligand trap prevented muscle wasting in a mouse model of experimental CKD.
Project description:Skeletal muscle wasting results from numerous conditions, such as sarcopenia, glucocorticoid therapy or intensive care. It prevents independent living in the elderly, predisposes to secondary diseases, and ultimately reduces lifespan. There is no approved drug therapy and the major causative mechanisms are not fully understood. Dual specificity phosphatase 22 (DUSP22) is a pleiotropic signaling molecule that plays important roles in immunity and cancer. However, the role of DUSP22 in skeletal muscle wasting is unknown. In this study, DUSP22 was found to be upregulated in sarcopenia patients and models of skeletal muscle wasting. DUSP22 knockdown or pharmacological inhibition with BML-260 prevented multiple forms of muscle wasting. Mechanistically, targeting DUSP22 suppressed FOXO3a, a master regulator of skeletal muscle wasting, via downregulation of the stress-activated kinase JNK, which occurred independently of aberrant Akt activation. DUSP22 targeting was also effective in human skeletal muscle cells undergoing atrophy. In conclusion, phosphatase DUSP22 is a novel target for preventing skeletal muscle wasting and BML-260 is a therapeutically effective small molecule inhibitor. The DUSP22-JNK-FOXO3a axis could be exploited to treat sarcopenia or related aging disorders.
Project description:Skeletal muscle wasting is commonly associated with chronic kidney disease (CKD), resulting in increased morbidity and mortality. However, the link between kidney and muscle function remains poorly understood. Here, we took a complementary interorgan approach to investigate skeletal muscle wasting in CKD. We identified an increased production and elevated blood levels of soluble pro-cachectic factor Activin A, directly linking experimental and human CKD to skeletal muscle wasting programs. Single cell sequencing data identified the expression of Activin A in specific kidney cell populations, namely a subpopulation of fibroblasts and cells of the juxtaglomerular apparatus. Based on our findings, we propose that persistent and increased kidney production of pro-cachectic factors combined with a lack of kidney clearance facilitate a vicious signalling kidney-muscle cycle, leading to exacerbated blood accumulation of Activin A, and thereby skeletal muscle wasting in CKD.
Project description:Investigating muscle wasting in a murine model of cancer cachexia, we identified Oncostatin M (OSM) as a potential mediator of inflammatory responses in skeletal muscle. OSM is a member of the IL-6 family of cytokines and has crucial functions in cell growth, differentiation, and inflammation. Our results demonstrate that OSM induces muscle atrophy. To understand if its effect is specific or it is a general effect of IL6 family cytokines, primary myotubes were treated with OSM, IL6 and LIF for 48hrs. Our findings showed that OSM potently induces muscle wasting in differentiated myotubes.