Knockout of C6orf120 in Rats Alleviates Concanavalin A-induced Autoimmune Hepatitis by Regulating Macrophage Polarization.

Objective: The effect of the functionally unknown gene C6orf120 on autoimmune hepatitis was investigated on C6orf120 knockout rats ( C6orf120 ^-/- ) and THP-1 cells.

Method: Six-eight-week-old C6orf120 ^-/- and wild-type (WT) SD rats were injected with Con A (16 mg/kg), and euthanized after 24 h. The sera, livers, and spleens were collected. THP-1 cells and the recombinant protein (rC6ORF120) were used to explore the mechanism in vitro. The frequency of M1 and M2 macrophages was analyzed using flow cytometry. Western blotting and PCR were used to detect macrophage polarization-associated factors.

Results: C6orf120 knockout attenuated Con A-induced autoimmune hepatitis. Flow cytometry indicated that the proportion of CD68 ⁺CD86 ⁺M1 macrophages from the liver and spleen in the C6orf120 ^-/- rats decreased. C6orf120 knockout induced downregulation of CD86 protein and the mRNA levels of related inflammatory factors TNF-α, IL-1β, and IL-6 in the liver. C6orf120 knockout did not affect the polarization of THP-1 cells. However, rC6ORF120 promoted the THP-1 cells toward CD68 ⁺CD80 ⁺M1 macrophages and inhibited the CD68 ⁺CD206 ⁺M2 phenotype.

Conclusion: C6orf120 knockout alleviates Con A-induced autoimmune hepatitis by inhibiting macrophage polarization toward M1 macrophages and reducing the expression of related inflammatory factors in C6orf120 ^-/- rats.