Paternal Sperm <i>Gnas</i> ‐ICR Epigenetic Programming Contributes to PPP‐Like Phenotypes in Female Offspring

The incidence of peripheral precocious puberty (PPP) in females has been rising steadily, emerging as a significant public health concern. However, the paternal developmental origins of PPP remain poorly understood. Using a rat model, we found that paternal preconception caffeine exposure (PPCE) induced PPP-like phenotypes in female offspring and showed paternal-line persistence to the F2 generation. Mechanistic analyses showed that PPCE induced a paternal glucocorticoid-elevated state and was associated with hypermethylation of the Gnas imprinting control region (ICR) in sperm. In offspring ovaries, this alteration was paralleled by increased Gnas-ICR methylation, reduced Nespas expression, increased Gnas expression, activation of the cAMP/PKA/CREB pathway and enhanced estrogen biosynthesis. Ovarian Gnas gain- and loss-of-function experiments supported a functional contribution of Gnas dysregulation to steroidogenesis and PPP-like phenotypes, while paternal GR antagonism attenuated sperm/ovarian methylation changes and offspring phenotypes. Exploratory human samples suggested a weak and method-sensitive association between plasma cortisol levels and sperm Gnas-ICR methylation. These findings support a paternal glucocorticoid-associated sperm Gnas-ICR mechanism that may contribute to offspring ovarian endocrine programming. Together, these findings provide a preclinical framework for understanding how paternal preconception endocrine status may shape offspring reproductive development through sperm-associated epigenetic programming.