Asbestosis is a prototypical type of fibrosis that is progressive and does not resolve. ER stress is increased in multiple cell types that contribute to fibrosis; however, the mechanism(s) by which ER stress in lung macrophages contributes to fibrosis is poorly understood. Here, we show that ER stress resulted in protein kinase RNA-like ER kinase (PERK; Eif2ak3 ) activation in humans with asbestosis. Similar results were seen in asbestos-injured mice. Mice harboring a conditional deletion of Eif2ak3 were protected from fibrosis. Lung macrophages from asbestosis individuals had evidence of metabolic reprogramming to fatty acid oxidation (FAO). Eif2ak3 ^fl/fl mice had increased oxygen consumption rate (OCR), whereas OCR in Eif2ak3 ^–/– Lyz2-cre mice was reduced to control levels. PERK increased activating transcription factor 4 ( Atf4 ) expression, and ATF4 bound to the Ppargc1a promoter to increase its expression. GSK2656157, a PERK-specific inhibitor, reduced FAO, Ppargc1a , and Aft4 in lung macrophages and reversed established fibrosis in mice. These observations suggest that PERK is a therapeutic target to reverse established fibrosis.

Understanding the glycosylation patterns of mitochondrial proteins in microglia is critical for determining their role in neurodegenerative diseases. Here, we present a novel and high-throughput methodology for glycomic analysis of mitochondrial proteins isolated from cultured microglia. This method involves the isolation of mitochondria from microglial cultures, quality assessment of mitochondrial samples, followed by an optimized protein extraction to maximize glycan detection, and infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) high-resolution accurate mass (HRAM) mass spectrometry to provide detailed profiles of mitochondrial glycosylation. This protocol emphasizes the importance of maintaining mitochondrial integrity during isolation and employs stringent quality control to ensure reproducibility, including measuring mitochondrial purity after extraction. This approach allows for the comprehensive profiling of glycosylation changes in microglial mitochondria under various experimental conditions in vitro, which offers insight into mitochondrial changes associated with neurodegenerative diseases. This approach could be adapted to other in vitro treatments, other cultured cell types, or primary cells. Through this standardized approach, we aim to advance the understanding of microglial mitochondrial glycans, contributing to the broader field of neurodegenerative research.

Understanding the glycosylation patterns of mitochondrial proteins in microglia is critical for determining their role in neurodegenerative diseases. Here, we present a novel and high-throughput methodology for glycomic analysis of mitochondrial proteins isolated from cultured microglia. This method involves the isolation of mitochondria from microglial cultures, quality assessment of mitochondrial samples, followed by an optimized protein extraction to maximize glycan detection, and infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) high-resolution accurate mass (HRAM) mass spectrometry to provide detailed profiles of mitochondrial glycosylation. This protocol emphasizes the importance of maintaining mitochondrial integrity during isolation and employs stringent quality control to ensure reproducibility, including measuring mitochondrial purity after extraction. This approach allows for the comprehensive profiling of glycosylation changes in microglial mitochondria under various experimental conditions in vitro, which offers insight into mitochondrial changes associated with neurodegenerative diseases. This approach could be adapted to other in vitro treatments, other cultured cell types, or primary cells. Through this standardized approach, we aim to advance the understanding of microglial mitochondrial glycans, contributing to the broader field of neurodegenerative research.