Targeting aryl hydrocarbon receptor signaling attenuates hypertension programmed by maternal Di-2-ethylhexylphthalate exposure.

Adverse early-life conditions can predispose offspring to long-term health risks. Phthalate exposure, particularly to di-2-ethylhexylphthalate (DEHP), during pregnancy and lactation has been implicated in programming offspring hypertension via aryl hydrocarbon receptor (AHR) activation, renin-angiotensin system (RAS) dysregulation, nitric oxide (NO) deficiency, and gut microbiota alterations. Using a maternal DEHP exposure rat model, we investigated whether blockade of AHR signaling-directly with the AHR inhibitor CH223191 or indirectly with the indoleamine 2,3-dioxygenase (IDO) inhibitor INCN-024360-prevents offspring hypertension. Pregnant rats received DEHP (10 mg/kg/day) by oral gavage throughout pregnancy and lactation, with or without CH223191 (10 mg/kg/day) or INCN-024360 (50 mg/kg/day). Maternal DEHP exposure induced sustained systolic hypertension in adult male offspring, accompanied by upregulation of renal AHR signaling and RAS components. This effect was attenuated by the IDO inhibitor (approximately 10 mmHg reduction in systolic blood pressure) and more effectively by the AHR inhibitor (approximately 16 mmHg reduction). Mechanistically, the IDO inhibitor reduced asymmetric dimethylarginine (an endogenous nitric oxide synthase inhibitor), renin, and CYP1A1 expression while increasing angiotensin-converting enzyme 2 (ACE2), whereas the AHR inhibitor suppressed renal AHR, renin, angiotensin-converting enzyme (ACE), and angiotensin II type 1 receptor (AT1R) expression and significantly enhanced short-chain fatty acid receptor expression. Both interventions were associated with distinct alterations in gut microbiota composition. These findings identify AHR as a key mechanistic link between early-life environmental phthalate exposure and programmed hypertension and support early-life AHR blockade as a potential preventive strategy for offspring cardiometabolic-kidney risk.