Endothelial Protein C Receptor Expression is Regulated by Sp1 Transcription Factor in Murine Microglia

Abstract

Objectives: Microglial cells are the central regulators of inflammatory responses in the brain and spinal cord. In addition to surveillance during resting state, they become activated due to microbial molecules and pathological insults. Endogenously expressed Activated protein C (APC) is an anticoagulant molecule with anti-inflammatory and cytoprotective roles, mediated by one of its receptors, Endothelial protein C receptor (EPCR). This study aimed to examine the basal and inducible expression of EPCR and unravel the regulatory mediators of its expression in microglia. Methods: We studied probable effects of Lipopolysaccharide (LPS), Peptidoglycan (PGN), and Polyinosinic–polycytidylic acid [Poly(I:C)] on EPCR mRNA and protein levels in N9 mouse microglial cells by qPCR and flow cytometry. Then, Cyclosporin A (CsA) and Mithramycin A (MMA) were used to inhibit transcription factors in the promoter region of the EPCR gene, which are Nuclear factor of activated T-cells, cytoplasmic 1 (NFATC1), and specificity protein 1 (Sp1). Results: As a result, the Sp1 transcription factor’s chemical inhibition impaired the upregulating effects of LPS and PGN on EPCR expression. Conclusion: Thus, our data suggest that LPS and PGN gave rise to increased EPCR levels in microglia, mainly through the Sp1 transcription factor.

Keywords

• microglia
• endothelial protein c receptor
• lipopolysaccharide
• peptidoglycan
• Sp1 transcription factor

Supporting Institution

The Scientific and Technological Research Council of Turkey (TUBITAK)

Project Number

114Z577

Thanks

The authors thank Dr. Erden Eren for his technical assistance.

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