Mitophagy drives maldifferentiation of tissue-resident memory T cells in patients with rheumatoid arthritis.

Objective: To investigate the function of mitophagy in instructing T-cell differentiation of patients with rheumatoid arthritis (RA).

Method: The mRNA and protein levels of optic atrophy protein-1 were detected in T cells from 94 RA patients and 37 age- and sex-matched healthy individuals by quantitative polymerase chain reaction and Western blotting. The impact of mitophagy on the differentiation of T cells was determined by flow cytometry. The therapeutic effect of targeting mitophagy was explored in humanized RA chimeras.

Results: Our study showed that T cells exerted high levels of mitophagy in RA patients. Since multiple T-cell subtypes play crucial roles in RA, we determined that mitophagy had a significant impact on the differentiation of tissue-resident memory T (Trm) cells, but not Th1 or Th17 cells. Importantly, we demonstrated that inhibiting mitophagy significantly reduced the number of Trm cells and downregulated inflammatory responses, as evidenced by diminished levels of T cell receptor β, interferon-γ, and interleukin-17A, in the humanized RA chimeras.

Conclusions: Mitophagy is elevated in RA T cells, leading to maldifferentiation of Trm cells in RA patients. Since these findings were obtained from clinical patients, mitophagy may be a potential therapeutic target for RA treatment.