Endocrine Abstracts

Background: Individuals with Differences of Sex Development (DSD) exhibit DNA damage, chromosomal variations, gonadal dysgenesis, Germ Cell Tumors (GCT) and infertility. DSD patients and men with Nonobstructive Azoospermia (NOA) show compromised genome stability linked to deregulated autophagy, Androgen Receptor (AR) signaling, and cGAS-STING pathway (CGSP) upregulation. This study investigates CGSP’s role in regulating Telomere Length (TL) via autophagy and AR signaling in the context of infertility.

Material and Methods: Blood leukocytes were collected from individuals with DSD (n = 40); including Swyer, Turner syndrome, DSD diagnosed with GCT (DSD-GCT)), and from men with nonobstructive azoospermia (n = 18) having abnormal embryogenesis after ICSI or diagnosed with spermatogonia arrest (SGA). Average relative TL was assessed by qPCR, long (>4,5kb) and short (<4,5kb) telomeres by Southern blot. Telomerase complex protein GAR1 was knocked-down (GAR1-KD) with siRNA in lymphoblastoid cell lines derived from individuals with DSD that were treated with AR-inhibitor Enzalutamide, autophagy inhibitor Bafilomycin A1 or activator Rapamycin. Fresh leukocytes samples from individuals with DSD were treated with genotoxic stress agent Olaparib, STING inhibitor H151 and activator G10. Statistical comparisons were conducted using ANOVA.

Results: NOA males showed increased long (P =<0,0001) and short (P =0,0002) telomers without changes in relative TL. Upregulated TL in Swyer (P =0,0069) and Turner (P =0,0064) but DSD-GCT was paralleled with increased long (P = <0,0001) and short (P =0,012) telomer fragments. In GAR1-KD DSD cells Enzalutamide treatment increased long (P =0,0201), short (P =0,025) and average (P =0,0472) TL, which was suppressed by Bafilomycin A1. The treatment with G10, but not H151 showed an increase in long (P =<0,0001) and short (P =0,0031) telomere fragments without changing average TL compared to control.

Conclusions: Our findings reveal altered telomere dynamics in infertile individuals with various diagnoses, characterized by accumulation of short and long telomeric fragments, reflecting telomere instability in parallel with telomere elongation. Functional studies proved autophagy to be critical for GAR1-dependent telomere synthesis. Modulation of cGAS-STING pathway further supports a mechanistic link between impaired DNA damage response, dysregulated autophagy and telomere fragmentation likely contributingto infertility and tumor susceptibility.