Endocrine Abstracts

Background: Genotoxic stress causes DNA damage that impairs gonadal cell function and fertility. Individuals with DSD, similar to men with non-obstructive azoospermia (NOA), exhibit increased DNA damage and altered DNA repair in blood and gonads, associated with dysgenic gonads, germ cell tumors, and compromised genomic integrity. Retinoic acid (RA), produced by Sertoli cells, is essential for meiosis, spermatogenesis, and germ cell differentiation. Our preliminary data revealed altered RA signaling genes in infertile individuals, including reduced expression of RA synthesis enzymes and increased expression of receptor genes, particularly RARA, under genotoxic stress. This study investigated whether balanced RA signaling in blood and gonadal cells modulates genotoxic stress and may represent a potential target for infertility treatment.

Methods: Blood samples from individuals with DSD (n = 11) and controls (n = 6) were treated with the RA activator TTNPB (0.5 μM), RA inhibitor WIN (1 μM), or RARA inhibitor AR7 (10 μM) for 2 hours. Primary testicular cells were exposed to RA (2 μM for 15 days) and Olaparib (100 μM for 24 hours) in ≥4 experiments. Gonadal tissues from individuals with NOA (n = 5) and DSD (n = 3) were analyzed for RARA/RARB colocalization and used for primary cell isolation. The DSD group included Swyer syndrome, CAIS, and Turner syndrome. ANOVA was used to statistics.

Results: In leukocytes from individuals with DSD, AR7 increased inflammatory and genotoxic stress markers, including IFNA, IFNB, IL1, IL6, IL12A, γH2AX, P62, and AR, mimicking the effects of RA hyperactivation by TTNPB. In contrast, WIN had minimal effects on these markers. ALDH1A1, ALDH1A2, RDH10, RDH11, and RARA were controls for treatments. Nuclear RARA and RARB were significantly increased in γH2AX-positive DNA-damaged Sertoli cells in gonads of DSD and NOA. In vitro, RA supplementation improved testicular cell integrity by increasing AR+ Sertoli cells and SALL4+ spermatogonia while reducing γH2AX+ cells. RA treatment rescued Olaparib-induced genotoxic stress, promoting RARA, Ki67, and SALL4 while reducing DNA damage.

Conclusions: Treatment of blood and gonadal cells from individuals with DSD and NOA individuals revealed a RA signaling-based molecular mechanism centered on RARA that mitigates genotoxic stress.