Captopril Restores Microglial Homeostasis and Reverses ASD-like Phenotype in a model of ASD induced by exposure in utero to anti-Caspr2 IgG.

We performed single-cell RNA sequencing (scRNA-seq) of hippocampal microglia to define transcriptional changes induced by prenatal exposure to maternal anti-Caspr2 antibodies and their modulation by treatment (Captopril). Male offspring were analyzed across four main groups: (1) Saline-treated Controls, (2)Captopril treated Controls, (3) Anti-Caspr2, saline-treated, and (4) Anti-Caspr2, Captopril-treated . scRNA-seq revealed a Captopril (blood–brain barrier-permeable ACE inhibitor)-responsive microglial subcluster in Anti-Caspr2 mice with dysregulated translation (eIF2 signaling) and metabolic pathways (mTOR, oxidative phosphorylation) relative to controls. Captopril reversed these pathway alterations and restored a homeostatic microglial transcriptional state. These data provide a single-cell transcriptomic resource linking prenatal anti-Caspr2 exposure to persistent microglial dysfunction and demonstrate pathway normalization with BBB-permeable ACE inhibition. Hippocampal brain macrophages (CD45+, CD11b++) were isolated from P42-P45 mice, and sorted on a BD FACSAria III. scRNA analysis included three mice from each group (Control Saline, Control Captopril, Anti-Caspr2 Saline, and Anti-Caspr2 Captopril), each representing a unique litter. Single-cell cDNA libraries were prepared according to the manufacturer’s instructions (Next GEM Single Cell 3′GEM v.3.1 protocol, 10x Genomics).