Anthony N. Gerber

Pulmonary fibrosis (PF) is a progressive lung condition characterized by irreversible scarring and high mortality, with limited effective treatments. Mitochondrial dysfunction has emerged as a critical factor in fibroblast activation in PF, although approaches to restore mitochondrial function remain underexplored. The present study investigated whether mitochondrial transfer from alveolar type II epithelial cells (A549) to patient-derived fibroblasts could restore mitochondrial function and bioenergetics. Histological analysis of fibrotic lungs reveals increased collagen deposition and elevated profibrotic markers, accompanied by reduced expression of mitochondrial biogenesis and respiratory proteins compared to non-fibrotic controls, indicating mitochondrial impairment. Freshly isolated donor mitochondria were functionally validated before mitoception using Seahorse analysis and patient-derived fibroblasts were confirmed by qRT-PCR using fibroblast-specific markers. In vitro transfer of mitochondria to diseased patient-derived fibroblasts exhibited a modest, dose and time-dependent increase in mitochondrial membrane potential compared to normal fibroblasts. Gene expression analysis revealed decreased fibrosis-associated markers and increased expression of mitochondrial and antioxidant genes following mitoception. Seahorse analysis after mitoception revealed enhanced ATP-linked respiration and improved selected mitochondrial bioenergetic parameters, whereas maximal respiration and spare respiratory capacity demonstrated variable responses. In contrast, normal fibroblasts displayed minimal changes. Collectively, these findings indicate that mitochondrial transfer modulates fibroblast bioenergetics and profibrotic signaling, supporting its potential as a therapeutic strategy for pulmonary fibrosis.