Biology subjects

Bilgic, S. N.

Publications and source records attributed to Bilgic, S. N..

3 recordsLinked to original sources

bioRxiv2023

Tumor-induced alterations in single-nucleus transcriptome of atrophying muscles indicate enhanced protein degradation and reduced oxidative metabolism

Tumor-induced skeletal muscle wasting in the context of cancer cachexia is a condition with profound implications for patient survival. The loss of muscle mass is a significant clinical obstacle and is linked to reduced tolerance to chemotherapy and increased frailty. We investigated muscle gene expression at single nucleus level in cachectic mice and revealed distinct myonuclear gene signatures and a shift towards type IIb myonuclei. Notably, atrophy-related genes, including Atrogin1, MuRF1 and Eda2r were upregulated in these myonuclei, emphasizing their crucial role in muscle wasting. Activation of the Ectodysplasin A2 Receptor (EDA2R) pathway suppressed gene sets related to muscle contraction and oxidative metabolism, indicating its involvement in transcriptional reprogramming. Our study also highlighted the negative impact of tumors on oxidative metabolism in muscle tissue and their influence on the transcriptomes of mononuclear cells in skeletal muscle. These findings contribute to a deeper understanding of the molecular mechanisms underlying cancer cachexia.

cell biology↗

bioRxiv2023

Activated Oncostatin M signaling drives cancer-associated skeletal muscle wasting

Progressive weakness and muscle loss are associated with multiple chronic conditions including muscular dystrophy and cancer. Cancer-associated cachexia, characterized by dramatic weight loss and fatigue, leads to reduced quality of life and poor survival. Inflammatory cytokines have been implicated in muscle atrophy, however, available anti-cytokine therapies failed to prevent muscle wasting in cancer patients. We previously reported that muscle-specific deletion of the Oncostatin M (OSM) receptor (OSMR) preserved muscle mass and function in tumor-bearing mice. Here, we show that OSM is a potent inducer of muscle atrophy. OSM triggers cellular atrophy in primary myotubes utilizing the JAK/STAT3 pathway. Identification of OSM targets by RNA sequencing revealed the induction of various muscle atrophy-related genes, including Atrogin1. OSM overexpression in mice caused muscle wasting while the neutralization of circulating OSM protected from tumor-driven loss of muscle mass and function. Our results indicate that activated OSM/OSMR signaling drives muscle atrophy, and the therapeutic targeting of this pathway may be useful in preventing muscle wasting.

cancer biology↗

bioRxiv2023

EDA2R/NIK signaling promotes skeletal muscle atrophy linked to cancer cachexia

Skeletal muscle atrophy is a hallmark of the cachexia syndrome that is associated with poor survival and reduced quality of life in cancer patients1. Muscle atrophy involves excessive protein catabolism and loss of muscle mass and strength2. An effective therapy against muscle wasting is lacking as mechanisms driving the atrophy process remain incompletely understood. Our gene expression analysis in muscle tissues revealed upregulation of Ectodysplasin A2 Receptor (EDA2R) in tumor-bearing mice and cachectic cancer patients. Here we show that activation of EDA2R signaling promotes skeletal muscle atrophy. Stimulation of primary myotubes with EDA2R ligand, EDA-A2, triggered pronounced cellular atrophy via inducing the expression of muscle atrophy-related genes Atrogin1 and MuRF1. EDA-A2-driven myotube atrophy involved activation of the noncanonical NF{kappa}B pathway and depended on NIK kinase activity. While EDA-A2 overexpression induced muscle wasting in mice, the deletion of EDA2R or muscle NIK protected tumor-bearing mice from the loss of muscle mass and function. Tumor-induced Oncostatin M upregulated muscle EDA2R expression and muscle-specific Oncostatin M Receptor (OSMR) knockout mice were resistant to tumor-driven muscle wasting. Our results demonstrate that EDA2R/NIK signaling mediates cancer-associated muscle atrophy in an OSM/OSMR-dependent manner. Thus, therapeutic targeting of these pathways may be beneficial in preventing muscle loss.

cancer biology↗