RNA sequencing of human brain organoids to evaluate sex-specific and opto-FGFR-mediated responses to Simplified 5 Ion GCR Simulation
This study aims to characterize transcriptomic responses to Simplified 5 Ion GCR Simulation  (simGCRsim) in human brain organoids derived from hiPSCs. Two independent RNA-seq experiments were conducted. The first set compared male- and female-derived organoids to evaluate sex-specific transcriptional responses to GCR. The second set assessed organoids derived from i) male hiPSCs expressing optogenetically-controlled FGFR (opto-FGFR) or mock constructs to explore FGFR signaling as a potential countermeasure and ii) one female hiPSC line (SC2131), with or without GCR exposure. Together, these datasets provide insight into both intrinsic sex differences and FGFR-dependent protective mechanisms in human neural tissues in the context of space radiation exposure. Overall design: Human brain organoids were generated from hiPSCs and subjected to two independent RNA sequencing experiments. Experiment 1: Organoids were derived from 6 male and 2 female hiPSC lines and matured for 60 days. Organoids from each line were either untreated (control) or exposed to 50 cGy of simGCRsim. RNA was extracted for sequencing to investigate sex-specific transcriptional responses to radiation. Experiment 2: Male hiPSC lines were engineered to express either opto-FGFR or a mock construct, or one female hiPSC line (SC2131), followed by brain organoid differentiation and 60-day maturation. Organoids were then either left untreated or exposed to 50cGy of simGCRsim. RNA was sequenced to assess FGFR-mediated modulation of radiation response or responses of female-derived brain organoids against GCR radiation. Each condition was represented by three biological replicates. Differential gene expression analyses were performed to identify radiation-induced transcriptomic alterations and FGFR-dependent protective mechanisms.