Sphingosine-1-Phosphate Receptor 2 Promotes Renal Microvascular Constriction and Kidney Injury Following Renal...

Area of Science:

• Nephrology
• Vascular Biology
• Biochemistry

Background:

• Ischemia-reperfusion (IR) injury is a major cause of acute kidney injury (AKI).
• Renal vascular resistance, regulated by afferent arteriole diameter, is critical in AKI.
• Sphingosine-1-phosphate (S1P) is a vasoconstrictor in renal afferent arterioles.

Purpose of the Study:

• To investigate if IR enhances afferent arteriolar sensitivity to S1P.
• To determine the role of S1P signaling in IR-induced renal microvascular dysfunction and AKI.

Main Methods:

• In vitro blood-perfused juxtamedullary nephron preparation in male rats.
• Assessment of afferent arteriolar diameter and reactivity to S1P after IR.
• Analysis of S1P receptor 2 (S1PR2) expression and S1P levels in kidney tissues.

Main Results:

• IR significantly reduced afferent arteriole diameter and increased sensitivity to S1P (8-fold reduction in EC50).
• S1PR2 blockade improved arteriolar diameter post-IR, indicating a role for endogenous S1P.
• IR upregulated S1PR2 and increased kidney S1P levels, while other vasoconstrictor responses remained unchanged.
• S1PR2 blockade reduced plasma creatinine, tubular damage, and kidney ROS in IR rats.

Conclusions:

• IR enhances renal microvascular S1P-S1PR2 signaling, contributing to afferent arteriolar constriction.
• This enhanced signaling negatively impacts kidney perfusion and promotes AKI.
• Targeting S1P-S1PR2 signaling may offer a therapeutic strategy for AKI.