Integrated single-cell and spatial transcriptomics of ovarian immune landscape reveal role of distinct macrophages in classic galactosemia associated with premature ovarian insufficiency

Premature ovarian insufficiency (POI) is a complication that affects 80% of females with classic galactosemia (CG), caused by mutations in the GALT gene. Immune system regulates normal physiological processes and pathological aspects of the ovarian function. While previous animal studies have shown that accumulation of toxic galactose metabolites trigger cellular stress pathways, contribute to the disease's complications, it remains unclear how these influence the immune landscape in CG patients. Here, we investigated the molecular and cellular changes in the ovarian immune environment that may impact the ovarian function contributing to early onset of POI in prepubteral girls with CG. We noticed a marked increase in both monocyte and tissue derived macrophages, and expression of pro-inflammatory cytokines in the CG ovary. Furthermore, we noticed oxidative stress induced activation of NLRP3 inflammasome, which contributed to recruitment of macrophages, induction of pyroptotic cell-death, and overall exacerbation of the inflammatory response.