P2Y1 Gene Deficiency Protects from Renal Disease Progression and Capillary Rarefaction during Passive Crescentic Glomerulonephritis

Abstract

The metabotropic receptor P2Y1 is necessary for full ADP-induced platelet activation and is localized on various intrinsic renal cells, including mesangial cells, podocytes, and endothelial cells. To date, nothing is known about the role of the P2Y1 receptor during inflammatory renal disease. The role of the P2Y1 receptor was investigated using 22 P2Y1 gene-deficient (؊/؊) and 27 wild-type (wt) mice during the time course of passive crescentic nephrotoxic glomerulonephritis. Six P2Y1 ؊/؊ and six wt mice served as undiseased controls. Renal tissues were harvested on days 1, 10, and 28 after disease induction. No renal phenotype was found in P2Y1 ؊/؊ versus wt mice. In contrast, during crescentic glomerulonephritis, approximately 50% of all wt mice died, whereas all P2Y1 ؊/؊ mice survived. Renal function as assessed by creatinine clearance measurements, glomerulosclerosis, and tubulointerstitial injury indices as well as glomerular and interstitial matrix expansion were improved significantly in P2Y1 ؊/؊ compared with wt mice. These changes were preceded by reduced glomerular and peritubular capillary rarefaction indices in P2Y1 ؊/؊ compared with wt mice. The alteration of the rates of both peritubular apoptosis and endothelial cell proliferation suggests improved capillary preservation in P2Y1 ؊/؊ mice early in disease (day 10) and an additional enhanced repair reaction in P2Y1 ؊/؊ mice at the late time point (day 28), whereas injury on day 1 seemed to be equivalent in both groups. It is concluded that loss of P2Y1 receptor function safeguards against capillary loss, fibrosis, and death by renal failure during experimental crescentic glomerulonephritis.

P2X receptors regulate adenosine diphosphate release from hepatic cells

“…Elevated circulating nucleotide levels and sustained purinergic signaling may consequently promote inflammatory diseases [7,8]. Consistent with this view, knockout of P2Y and ion channel purinergic receptors (P2X) in mice has been shown to significantly reduce inflammatory disease in the heart, liver, kidney, and other tissues [9][10][11][12][13][14].…”

Platelets are relevant mediators of renal injury induced by primary endothelial lesions

“…Periodic acid-Schiff (PAS) and acid fuchsin orange G (AFOG) stainings of three 3-m interval sections of each biopsy were performed to asses renal injury and fibrin deposition. For immunofluorescence microscopy, further sections were incubated with the following primary and secondary antibodies as indicated and also previously published (17,19,20,22): glycoprotein Ib␣, a rat monoclonal antibody against mouse glycoprotein Ib for specific staining of platelets (5); mouse endothelial cell antigen (MECA)-32, a rat monoclonal antibody against MECA-32 for specific detection of peritubular endothelial cells (16); CD31, a rat monoclonal antibody against mouse platelet-endothelial cell adhesion molecule-1 for specific detection of endothelial cells (46); PCNA, a murine monoclonal antibody against PCNA to detect actively proliferating cells (19A2, Merck Millipore) (23); and F4/80, a rat monoclonal antibody (Invitrogen, Life Technologies) to detect mouse macrophages/monocytes as inflammatory cell types. All antibodies were diluted in sterile PBS containing 1% (wt/vol) BSA.…”

Extrarenal Progenitor Cells Do Not Contribute to Renal Endothelial Repair

“…Tissues for light microscopy were fixed in zinc fixative solution (BD Pharmingen, Heidelberg, Germany), embedded in paraffin and cut into 2 mm sections for indirect immunoperoxidase staining as previously described. 52 Staining for CD31 was performed using a rat anti-mouse CD31/PECAM-1 antibody (BD Biosciences, Heidelberg, Germany). Negative controls for immunostaining included either deletion of the primary antibody or substitution of the primary antibody with equivalent concentrations of an irrelevant murine or rat monoclonal antibodies.…”