Related Experiment Video
Updated: Aug 25, 2025
Laser Microdissection-Based Protocol for the LC-MS/MS Analysis of the Proteomic Profile of Neuromelanin Granules
Published on: December 16, 2021
Data-independent acquisition-based quantitative proteomic analysis of m.3243A>G MELAS reveals novel potential
Xueli Chang1, Zhaoxu Yin1, Wei Zhang1
1Department of Neurology, First Hospital of Shanxi Medical University, Taiyuan, Shanxi, China.
Abstract:
The pathogenesis of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke like episodes (MELAS) syndrome has not been fully elucidated. The m.3243A > G mutation which is responsible for 80% MELAS patients affects proteins with undetermined functions. Therefore, we performed quantitative proteomic analysis on skeletal muscle specimens from MELAS patients. We recruited 10 patients with definitive MELAS and 10 age- and gender- matched controls. Proteomic analysis based on nanospray liquid chromatography-mass spectrometry (LC-MS) was performed using data-independent acquisition (DIA) method and differentially expressed proteins were revealed by bioinformatics analysis. We identified 128 differential proteins between MELAS and controls, including 68 down-regulated proteins and 60 up-regulated proteins. The differential proteins involved in oxidative stress were identified, including heat shock protein beta-1 (HSPB1), alpha-crystallin B chain (CRYAB), heme oxygenase 1 (HMOX1), glucose-6-phosphate dehydrogenase (G6PD) and selenoprotein P. Gene ontology and kyoto encyclopedia of genes and genomes pathway analysis showed significant enrichment in phagosome, ribosome and peroxisome proliferator-activated receptors (PPAR) signaling pathway. The imbalance between oxidative stress and antioxidant defense, the activation of autophagosomes, and the abnormal metabolism of mitochondrial ribosome proteins (MRPs) might play an important role in m.3243A > G MELAS. The combination of proteomic and bioinformatics analysis could contribute potential molecular networks to the pathogenesis of MELAS in a comprehensive manner.
Insights
Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke like episodes (MELAS) pathogenesis involves altered protein expression, particularly in oxidative stress and mitochondrial ribosome proteins. This proteomic study reveals key molecular players in MELAS.
Area of Science:
- Biochemistry
- Genetics
- Molecular Biology
Background:
- The exact mechanisms driving mitochondrial myopathy, encephalopathy, lactic acidosis and stroke like episodes (MELAS) remain unclear.
- The common m.3243A>G mutation impacts proteins with unknown functions, necessitating further investigation.
Purpose of the Study:
- To conduct a quantitative proteomic analysis of skeletal muscle from MELAS patients to identify differentially expressed proteins.
- To elucidate the molecular pathogenesis of MELAS, particularly concerning the m.3243A>G mutation.
Main Methods:
- Quantitative proteomic analysis using nanospray liquid chromatography-mass spectrometry (LC-MS) with data-independent acquisition (DIA).
- Recruitment of 10 MELAS patients and 10 age/gender-matched controls.
- Bioinformatics analysis including Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis.
Main Results:
- Identified 128 differentially expressed proteins (68 down-regulated, 60 up-regulated) between MELAS patients and controls.
- Key proteins involved in oxidative stress (e.g., HSPB1, HMOX1, G6PD) were identified.
- Enrichment analysis highlighted pathways related to phagosomes, ribosomes, and peroxisome proliferator-activated receptors (PPARs).
Conclusions:
- Oxidative stress imbalance, autophagosome activation, and abnormal mitochondrial ribosome protein metabolism are implicated in m.3243A>G MELAS pathogenesis.
- Proteomic and bioinformatics approaches offer comprehensive insights into MELAS molecular networks.
- Further research into these identified proteins and pathways could reveal therapeutic targets.
