Arachidonic acid is involved in high-salt diet-induced coronary remodeling through stimulation of the IRE1α/XBP1s/RUNX2/OPN signaling cascade

Background: The impact of a high-salt (HS) diet on metabolic disturbances in individuals with coronary heart disease remains unclear. The arachidonic acid (AA) metabolic pathway is closely linked to the development of cardiometabolic diseases and atherosclerotic cardiovascular diseases. Furthermore, endoplasmic reticulum stress (ERS) has emerged as a major contributor to cardiometabolic diseases. AA-related inflammation and ERS are hypothesized to play a role in HS diet-induced coronary remodeling.

Methods: Rats were subjected to an HS diet for 4 weeks, and the serum concentration of AA was measured via enzyme-linked immunosorbent assay. Immunofluorescence staining and vascular tension measurements were conducted on coronary arteries. In addition, AA-stimulated coronary artery smooth muscle cells (CASMCs) were treated with ERS inhibitors to explore the underlying pathway involved.

Results: Increased susceptibility to myocardial infarction in the HS diet-fed rats was accompanied by increased serum AA concentrations and increased expression of the key AA metabolic enzyme cyclooxygenase-2 (COX-2). AA incubation weakened the contraction of denuded coronary arteries, reduced the expression of contraction markers, and increased the fluorescence intensity of synthetic and ERS response markers in coronary arteries. Further investigation of CASMCs revealed that AA-induced phenotypic transformation was mediated via the ERS pathway.

Conclusions: ERS and AA were found to be stimulated in CASMCs following an HS diet. AA triggers an ERS response through COX-2 catalysis, and the downstream inositol requiring enzyme 1 - X-box binding protein-1 - Osteopontin pathway may contribute to the AA-induced phenotypic transformation of CASMCs, resulting in dysfunctional coronary tension. This study may provide potential therapeutic targets for cardiovascular diseases associated with excessive AA-derived ERS.

Arachidonic acid; Coronary artery smooth muscle cells; Endoplasmic reticulum stress; High-salt diet; Osteopontin; Phenotypic transformation.