Crosstalk between miRNA and protein expression profiles in nitrate exposed brain cells

Abstract

Growing evidence reported a strong association between the ingestion of nitrate and adverse health consequences in humans, including its detrimental impact on the developing brain. The present study identified miRNAs and proteins in SH-SY5Y human neuroblastoma cells and HMC3 human microglial cells using high throughput techniques in response to nitrate level most prevalent in the environment (mainly India) (X) and an exceptionally high nitrate level (5X) that can be reached in the near future. Cells were exposed to mixtures of nitrates for 72 h at doses of X and 5X, 320 mg/L and 1600 mg/L, respectively. OpenArray and LCMS analysis revealed that maximum deregulation in miRNAs and proteins was found in cells exposed to 5X dose. Top deregulated miRNAs include miR-34b, miR-34c, miR-155, miR-143, and miR-145. The proteomic profiles of both cell types include proteins that are potential targets of deregulated miRNAs. These miRNAs and their targeted proteins are involved in multiple functions, including cellular senescence, cell cycle, apoptosis, neuronal disorders, brain development, and homeostasis. Further, measuring mitochondrial bioenergetics in cells exposed to nitrate using a Seahorse XFp flux analyzer revealed that a 5X dose causes a significant reduction in oxygen consumption rate (OCR) and other bioenergetics parameters in both cell types. In summary, our studies have demonstrated that 5X dose of nitrate significantly alters cellular physiology and functions by deregulating several miRNAs and proteins. However, X dose of nitrate that is most prevalent in the environment has not caused any adverse effects on any cell type.