Fig 1: Deletion of Neurexin-3 in PVN CaMKIIα-expressing neurons regulates body weight, adiposity, and glucose homeostasis. (A-B) Western blot analysis indicates upregulated Nrxn3 protein levels in the PVN following cold exposure (4 °C, 3 h, A) or after 36 h of fasting (B), compared to control conditions (n = 4 mice per group). (C) Left: Schematic diagram of viral injection. Top right: Western blot analysis of Nrxn3 protein levels in PVN. Bottom right: Representative immunofluorescence staining images demonstrating selective transduction of PVN neurons by AAV9-CaMKIIα-Cre-EGFP injection in Nrxn3-floxed mice (n = 4 per group). (D) Nrxn3 CKO mice show a progressive increase in body weight gain compared to controls (n = 5 per group). (E) Representative images of the mice two months post-virus injection. (F-G) Body composition analysis two months after virus injection reveals increased fat mass (F) and total fat percentage (G) in Nrxn3 CKO mice (n = 5 per group). (H) Representative images of visceral fat and other tissues in CTL and CKO mice. (I) ANY-MAZE software (Stoelting Co.) records the total distance traveled in a 50 cm (L) x 50 cm (W) x 34.5 cm (H) open field arena, which shows no significant change in Nrxn3 CKO mice during the open field test (n = 5–6 per group, total duration: 10 min). (J) Daily food intake does not differ significantly between Nrxn3 CKO and CTL mice (n = 5 per group). (K) Blood glucose levels were measured at 0, 15, 30, 60, 120, and 180 min after glucose injection. Mice were fasted for 12 h before the 0-minute measurement (n = 5 per group). Data are presented as mean ± SEM. ns, not significant, *P < 0.05, **P < 0.01, ***P < 0.001, as determined by Student’s t-test