Dataset Information

Muscle proteomics of mitochondrial disorders

ABSTRACT: Mitochondrial DNA mutations progressively compromise the respiratory chain of skeletal muscle, resulting in a mosaic of metabolically healthy and defective fibers. This heterogeneity is the best diagnostic signpost of mitochondrial disorders. However, the single fiber investigation of its molecular basis has been beyond the capability of large-scale technologies so far. We here use a novel approach to single muscle fibers proteomics, based on laser capture microdissection to excise thin sections of individual muscle fibers from frozen biopsies. Combined with a highly sensitive mass spectrometry-based proteomics workflow, this technique allowed us to analyze healthy and defective muscle fibers from patients with mitochondrial disorders.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Skeletal Muscle Fiber

DISEASE(S): Mitochondrial Myopathy

SUBMITTER: Marta Murgia

LAB HEAD: Thomas Klopstock

PROVIDER: PXD010489 | Pride | 2019-11-15

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	MaxQuant_Output.zip	Other
	MurgiaetalMitomyopathiesRAW.rar	Other

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Publications

Proteomics of Cytochrome c Oxidase-Negative versus -Positive Muscle Fiber Sections in Mitochondrial Myopathy.

Murgia Marta M Tan Jing J Geyer Philipp E PE Doll Sophia S Mann Matthias M Klopstock Thomas T

Cell reports 20191201 12

The mosaic distribution of cytochrome c oxidase+ (COX+) and COX- muscle fibers in mitochondrial disorders allows the sampling of fibers with compensated and decompensated mitochondrial function from the same individual. We apply laser capture microdissection to excise individual COX+ and COX- fibers from the biopsies of mitochondrial myopathy patients. Using mass spectrometry-based proteomics, we quantify >4,000 proteins per patient. While C ...[more]

PMID: 31851916

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Project description:Septic patients treated in the intensive care unit (ICU) often develop multiple organ failure including persistent skeletal muscle dysfunction which results in the patientâs protracted recovery process. We have demonstrated that muscle mitochondrial enzyme activities are impaired in septic ICU patients resulting in decreased cellular energy which will interfere with muscle function and metabolism. Here we use detailed phenotyping and genomics to elucidate mechanisms leading to these impairments. Methodology/Principle Findings Utilising biopsy material from seventeen patients and ten age-matched controls we demonstrate that neither mitochondrial in vivo protein synthesis nor expression of mitochondrial genes are compromised. Indeed, there was partial activation of the mitochondrial biogenesis pathway involving NRF2?/GABP and its target genes TFAM, TFB1M and TFB2M yet clearly this failed to maintain mitochondrial function. We therefore utilised transcript profiling and pathway analysis of ICU patient skeletal muscle to generate insight into the molecular defects driving loss of muscle function and metabolic homeostasis. Gene ontology analysis of Affymetrix analysis demonstrated substantial loss of muscle specific genes, a global oxidative stress response related to most probably cytokine signalling, altered insulin related signalling and a substantial overlap between patients and muscle wasting/inflammatory animal models. MicroRNA 21 processing appeared defective suggesting that post-transcriptional protein synthesis regulation is altered by disruption of tissue microRNA expression. Finally, we were able to demonstrate that the phenotype of skeletal muscle in ICU patients is not merely one of inactivity, it appears to be an actively remodelling tissue, influenced by several mediators, all of which may be open to manipulation with the aim to improve clinical outcome. Conclusions/Significance This first combined protein and transcriptome based analysis of human skeletal muscle obtained from septic patients demonstrated that losses of mitochondria and muscle mass are accompanied by sustained protein synthesis (anabolic process) while dysregulation of transcription programmes appears to fail to compensate for increased damage and proteolysis. Our analysis identified both validated and novel clinically tractable targets to manipulate these failing processes and pursuit of these could lead to new potential treatments. Experiment Overall Design: 13 septic samples, 8 controls