UDPG/P2Y14-STAT1 axis mediates LPS-induced reactive astrogliosis

Abstract

Astrocytes play a vital role in neuroinflammatory processes within the central nervous system (CNS). Increasing evidence suggests that purinergic G protein-coupled receptor P2Y₁₄ is associated with neuroinflammation. However, the expression, distribution, and function of P2Y₁₄ in astrocytes remain unclear. This study aimed to investigate the expression of P2Y₁₄ receptors in astrocytes and their regulatory role in astrocytic inflammatory responses. P2Y₁₄ expression was confirmed in primary astrocytes isolated from the mouse cerebral cortex using immunofluorescence techniques. Western blot and RT-qPCR analyses showed that lipopolysaccharide (LPS) stimulation significantly increased P2Y₁₄ expression in astrocytes. The antagonist of P2Y₁₄ receptor, 4-(piperidin-4-yl)-phenyl)-7-(4-(trifluoromethyl)-phenyl2-naphthoic acid (PPTN) reduced glial fibrillary acidic protein (GFAP) expression, while the agonist of P2Y₁₄ receptor, uridine diphosphate glucose (UDPG) promoted it in astrocytes. Mechanistically, PPTN inhibited the expression of signal transducer and activator of transcription 1 (STAT1) and its phosphorylated form (p-STAT1), while UDPG enhanced the activation of STAT1/p-STAT1. Treatment with the P2Y₁₄ antagonist PPTN resulted in significant inhibition of interleukin (IL)-6, IL-18, and tumor necrosis factor-alpha (TNF-α) release. By contrast, stimulation of the P2Y₁₄ receptor with its agonist UDPG induced a substantial increase in the levels of these inflammatory mediators. These results were further validated in the cell line of mouse astrocyte C8-D1A using pharmacological approaches and lentiviral transduction to modulate P2Y₁₄ expression. This study confirmed that astrocytes express functional P2Y₁₄ receptors and demonstrated their key role in regulating astrocyte activation and inflammatory responses. This regulation may be achieved through the UDPG/P2Y₁₄-STAT1 signaling axis, which provides a new molecular basis for understanding the regulatory mechanisms of astrocytic inflammatory responses.

Keywords: P2Y(14) receptor; interleukin-6; lipopolysaccharide; reactive astrogliosis; signal transducer and activator of transcription 1.