Mitochondrial dysfunction and fatigue in Sjögren's disease.

Area of Science:

• Immunology
• Cellular Biology
• Metabolic Research

Background:

• Sjögren's disease (SjD) is a chronic autoimmune disorder characterized by inflammation, dryness, and significant fatigue.
• Fatigue in SjD may stem from impaired cellular bioenergetics, specifically mitochondrial dysfunction.
• Mitochondria, the cell's powerhouses, are normally recycled via mitophagy; impaired mitophagy leads to the accumulation of dysfunctional mitochondria and increased oxidative stress.

Purpose of the Study:

• To investigate the hypothesis that mitochondrial dysregulation in T cells is associated with fatigue in Sjögren's disease.
• To explore the role of mitophagy in the pathogenesis of SjD-related fatigue.

Main Methods:

• A case-control study involving T cells isolated from Sjögren's disease (SjD) patients, non-Sjögren's sicca (NSS) subjects, and healthy controls.
• Analysis of T cell mitochondrial respiration using Seahorse technology (measuring oxygen consumption rate and extracellular acidification rate).
• Bioinformatic analysis of public microarray data to identify a mitophagic transcriptional signature and stratify SjD patients.

Main Results:

• T cells from SjD and NSS subjects exhibited significantly lower basal oxygen consumption rate (OCR), ATP-linked respiration, maximal respiration, and reserve capacity compared to healthy individuals.
• No significant differences were observed in non-mitochondrial respiration, basal glycolysis, or glycolytic reserve between groups.
• Fatigue measures correlated with altered OCR in SjD patients, and transcriptional analysis revealed dynamic changes related to mitophagy pathways.

Conclusions:

• Mitochondrial dysfunction is a significant feature in Sjögren's disease T cells.
• Impaired mitochondrial function and altered mitophagy pathways are strongly associated with fatigue in SjD.
• These findings underscore the importance of investigating mitochondrial health and bioenergetics in SjD management.