LncRNA NONRATT021972 siRNA attenuates P2X7 receptor expression and inflammatory cytokine production induced by combined high glucose and free fatty acids in PC12 cells

Diabetic neuropathy (DNP) is a frequent chronic complication of diabetes mellitus with potentially life-threatening outcomes. High glucose and elevated free fatty acids (FFAs) have been recently recognized as major causes of nervous system damage in diabetes. Our previous study has indicated extracellular stimuli, such as high glucose and/or FFA stress, may activate the p38 mitogen-activated protein kinase (MAPK) signaling pathway and induce a p38 MAPK-dependent sensitization of the P2X7 receptor and release of inflammatory factors in PC12 cells, while the mechanisms underlying remain to be elucidated. Long noncoding RNAs (lncRNAs) play important roles in diverse biological processes, including activation of a series of pathway signalings. Here, we showed combined high d-glucose and FFAs (HGHF) induced an increment of lncRNA-NONRATT021972 (NONCODE ID, nc021972) in PC12 cells. Nc021972 small interference RNA (siRNA) alleviated HGHF-induced activation of p38 MAPK, expression of the P2X7 receptor, and Ca²⁺]_i increment upon P2X7 receptor activation. Further experiments showed that there existed a crosstalk between nc021972 and the p38 MAPK signaling pathway. Inhibition of p38 MAPK signaling decreased nc021972-induced expression of the P2X7 receptor and Ca²⁺]_i increment upon P2X7 receptor activation. Also, nc021972 siRNA inhibited HGHF-induced PC12 release of TNF-α and IL-6 and rescued decreased cell viability mediated by the P2X7 receptor. Therefore, inhibition of nc021972 may serve as a novel therapeutic strategy for diabetes complicated with nervous inflammatory diseases.