Per- and Polyfluoroalkyl Substances Induces Salt-Sensitive Hypertension by Upregulating Epithelial Sodium Channel - The First Experimental Evidence Supporting Causality

Abstract

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals found in the plasma of 98% of Americans. Epidemiological studies associate PFAS exposure with hypertension and kidney dysfunction, but causality and mechanisms remain unclear. We examined the effects of a mixture of 4 PFAS commonly detected in humans, including PFOA, PFOS, PFHxS, and PFNA, on blood pressure, salt sensitivity, and renal injury in 129S6 mice. Exposure to a lower dose for 3 weeks produced plasma PFAS levels in mice resembling occupational and regional environmental exposures; while a upper dose achieved levels similar to PFAS production workers. PFAS induced dose-dependent pressor effects in male but not female mice on a 0.4% low salt diet. During 4% high salt feeding, PFAS induced greater salt-sensitive hypertension in male mice, accompanied by glomerulopathy, interstitial fibrosis, and a trend towards increased albuminuria. Pressor effects were independent of plasma norepinephrine. Single-cell RNA sequencing of kidneys revealed most transcriptional changes in proximal tubule, thick ascending limb, and collecting duct, with enrichment of pathways in cholesterol synthesis, mitochondria respiration, ATP production, and transmembrane transporter activity. PFAS markedly increased the mRNA and protein of the pore-forming subunit of epithelial sodium channel (ENaC), with no change in {beta}ENaC and a slight reduction in {gamma}ENaC protein. Elevated ENaC coincided with a 30% decrease in Nedd4-2 phosphorylation (Ser448), suggesting reduced ENaC ubiquitination and degradation. However, protein expression of 1 Na+-K+-ATPase and serum- and glucocorticoid-regulated kinase 1 (SGK1) as well as SGK1 phosphorylation (Ser78) were unaltered. Amiloride abolished salt-induced hypertension in lower-dose mice but only partially corrected hypertension in the upper dose group. Taken together, our results provide causal evidence that PFAS exposure promotes hypertension, salt sensitivity, and kidney injury via renal epithelial mechanisms, supporting and extending human epidemiologic observations. Translational StatementOur findings establish four PFAS as causal drivers of salt-sensitive hypertension and kidney injury through convergent effects on ENaC and other tubular sodium transporters. These results not only provide a mechanistic explanation for epidemiologic associations but also identify PFAS as environmental amplifiers of dietary sodium risk. Given the ubiquity of human exposure, reducing PFAS burden alongside salt reduction may represent a complementary strategy to curb the global epidemic of hypertension and kidney disease.