Loss of endogenous estrogen alters mitochondrial metabolism and muscle clock‐related protein Rbm20 in female mdx mice

Abstract

Female carriers of a Duchenne muscular dystrophy (DMD) gene mutation manifest exercise intolerance and metabolic anomalies that may be exacerbated following menopause due to the loss of estrogen, a known regulator of skeletal muscle function and metabolism. Here, we studied the impact of estrogen depletion (via ovariectomy) on exercise tolerance and muscle mitochondrial metabolism in female mdx mice and the potential of estrogen replacement therapy (using estradiol) to protect against functional and metabolic perturbations. We also investigated the effect of estrogen depletion, and replacement, on the skeletal muscle proteome through an untargeted proteomic approach with TMT‐labelling. Our study confirms that loss of estrogen in female mdx mice reduces exercise capacity, tricarboxylic acid cycle intermediates, and citrate synthase activity but that these deficits are offset through estrogen replacement therapy. Furthermore, ovariectomy downregulated protein expression of RNA‐binding motif factor 20 (Rbm20), a critical regulator of sarcomeric and muscle homeostasis gene splicing, which impacted pathways involving ribosomal and mitochondrial translation. Estrogen replacement modulated Rbm20 protein expression and promoted metabolic processes and the upregulation of proteins involved in mitochondrial dynamics and metabolism. Our data suggest that estrogen mitigates dystrophinopathic features in female mdx mice and that estrogen replacement may be a potential therapy for post‐menopausal DMD carriers.

Haptoglobin and glutamine synthetase may biomark cachexia induced by anti-acute myeloid leukemia chemotherapy

“…TMT labelling proteomics on quadriceps samples were performed as previously described [13] as per Monash Proteomics and Metabolomics Platform data-dependent methodology [14]. Bioinformatics, Reactome (v83)based pathways enrichment and deep pathways probing was performed as previously described [13].…”

“…TMT labelling proteomics on quadriceps samples were performed as previously described [13] as per Monash Proteomics and Metabolomics Platform data-dependent methodology [14]. Bioinformatics, Reactome (v83)based pathways enrichment and deep pathways probing was performed as previously described [13]. Our analysis approach enables the detection of alterations in pathways that could remain unobserved when scoping only differentially expressed proteins because individual proteins might not provide comprehensive insights into how a specific pathway is changing when assessed through global, untargeted proteomic-level statistical comparisons.…”

“…Quadriceps samples were prepared and processed for TMT labelling and fractionation as previously described [17]. Liquid chromatography-mass spectrometric (LC-MS) analysis was conducted using an Orbitrap Eclipse Tribrid mass spectrometer (Thermo Scientific, Bremen, Germany) attached to a Nano LC system (Dionex Ultimate 3000 RSLCnano).…”

“…Reporter ion quantifiers used a unique plus razor with analysis centred on protein groups for shared peptide sequences using all peptides for abundance determination; quantitative values were corrected for stable isotope label impurities according to the manufacturer's values. Bioinformatic data analysis was performed as previously described [17]. A cut-off of the adjusted p-value of 0.05 (Benjamini-Hochberg method) and a log2 fold change of 0.75 was applied to determine significantly regulated proteins in the different pairwise comparisons.…”