Crosstalk Between miRNA and Protein Expression Profiles in Nitrate-Exposed Brain Cells

Growing evidence reported a strong association between the nitrate ingestion 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 (India) as X dose and an exceptionally high nitrate level as 5X dose 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 maximum deregulation in miRNAs and proteins 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 involve in multiple functions, including metabolic processes, mitochondrial functions, autophagy, necroptosis, apoptosis, neuronal disorders, brain development, and homeostasis. Furthermore, measuring mitochondrial bioenergetics in cells exposed to nitrate revealed that a 5X dose causes a significant reduction in oxygen consumption rate (OCR) and other bioenergetic parameters in both cell types. In summary, our studies have demonstrated that a 5X dose of nitrate significantly alters cellular physiology and functions by deregulating several miRNAs and proteins. However, X dose of nitrate has not caused any adverse effects on any cell type.