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This study aimed to investigate the role of bone marrow stromal cell antigen-1 (Bst1; also known as CD157) in acute kidney injury (AKI). Bst1 is a cell surface molecule with various enzymatic activities and downstream intracellular signaling pathways that modulate the immune response. Previous research has linked Bst1 to diseases such as ovarian cancer, Parkinson's disease, and rheumatoid arthritis. We used bilateral ischemia-reperfusion injury (IRI) as an AKI model and created bone marrow chimeric mice to evaluate the role of Bst1 in bone marrow-derived cells. We also used flow cytometry to identify Bst1/CD157 expression in hematopoietic cells and evaluate immune cell dynamics in the kidney. The findings showed that Bst1-deficient ( Bst1 -/- ) mice were protected against renal bilateral IRI. Bone marrow chimera experiments revealed that Bst1 expression on hematopoietic cells, but not parenchymal cells, induced renal IRI. Bst1 was mainly found in B cells and neutrophils by flow cytometry of the spleen and bone marrow. In vitro, migration of neutrophils from Bst1 -/- mice was suppressed, and adoptive transfer of neutrophils from wild-type Bst1 +/+ mice abolished the renal protective effect in Bst1 knockout mice. In conclusion, the study demonstrated that Bst1 -/- mice are protected against renal IRI and that Bst1 expression in neutrophils plays a crucial role in inducing renal IRI. These findings suggest that targeting Bst1 in neutrophils could be a potential therapeutic strategy for AKI. NEW & NOTEWORTHY mice revealed a protective effect against renal bilateral ischemia-reperfusion injury (IRI). Adoptive transfer studies confirmed that Bst1 expression in hematopoietic cells, especially neutrophils, contributed to renal bilateral IRI.Bst1 -/- mice revealed a protective effect against renal bilateral ischemia-reperfusion injury (IRI). Adoptive transfer studies confirmed that Bst1 expression in hematopoietic cells, especially neutrophils, contributed to renal bilateral IRI.

Progressive tubulointerstitial fibrosis may occur after acute kidney injury due to persistent inflammation. Purinergic signaling by 5'-ectonucleotidase, CD73, an enzyme that converts AMP to adenosine on the extracellular surface, can suppress inflammation. The role of CD73 in progressive kidney fibrosis has not been elucidated. We evaluated the effect of deletion of CD73 from kidney perivascular cells (including pericytes and/or fibroblasts of the Foxd1 + lineage) on fibrosis. Perivascular cell expression of CD73 was necessary to suppress inflammation and prevent kidney fibrosis in Foxd1CreCD73 fl/fl mice evaluated 14 days after unilateral ischemia-reperfusion injury or folic acid treatment (250 mg/kg). Kidneys of Foxd1CreCD73 fl/fl mice had greater collagen deposition, expression of proinflammatory markers (including various macrophage markers), and platelet-derived growth factor recepetor-β immunoreactivity than CD73 fl/fl mice. Kidney dysfunction and fibrosis were rescued by administration of soluble CD73 or by macrophage deletion. Isolated CD73 -/- kidney pericytes displayed an activated phenotype (increased proliferation and α-smooth muscle actin mRNA expression) compared with wild-type controls. In conclusion, CD73 in perivascular cells may act to suppress myofibroblast transformation and influence macrophages to promote a wound healing response. These results suggest that the purinergic signaling pathway in the kidney interstitial microenvironment orchestrates perivascular cells and macrophages to suppress inflammation and prevent progressive fibrosis.

The mechanisms involved in renal ischemia-reperfusion injury (IRI) are complex and appear to involve the early participation of bone marrow-derived cells. T lymphocytes participate in the pathogenesis of IRI. Sphingosine 1-phosphate (S1P) induces peripheral T cell depletion. Therefore, we hypothesized that S1P1 receptor activation protects kidney from IRI. FTY-720, a non-receptor-selective sphingosine analog, was given intraperitoneally to C57BL/6 mice, and animals were subjected to ischemia for 32 min followed by reperfusion for 24 h. Plasma creatinine, blood count, myeloperoxidase (MPO) activity, and renal histology were determined. IRI led to a marked increase in plasma creatinine, MPO activity, leukocyte infiltration, and vascular permeability. FTY-720 significantly decreased plasma creatinine in a dose-response manner with a maximal reduction of approximately 73 and approximately 69% with doses of 240 and 48 microg/kg, respectively. MPO, leukocyte infiltration, vascular permeability, and peripheral blood lymphocyte counts were markedly decreased with FTY-720 treatment. The protective effect of FTY-720 was reversed with VPC-44116, a selective S1P1 receptor antagonist. Furthermore, SEW-2871, a selective S1P1 agonist, significantly decreased plasma creatinine in a dose-response manner with a maximal reduction of approximately 70% with a dose of 10 mg/kg. Analysis of kidneys by light microscopy revealed minimal histological signs of ischemic injury with FTY-720 or SEW-2871 treatment compared with the vehicle group. Using RT-PCR, we found a time-dependent increase in the S1P1 mRNA expression following IRI that begins after 2 h with the maximum expression at approximately 4 h. We conclude that the protective effect of FTY-720 is due primarily to activation of S1P1 receptors. The mechanism of protection is not known but may be related to peripheral lymphocyte depletion or direct effects on kidney cells expressing S1P1 receptor.

The role of monocytes/macrophages in the pathogenesis of ischemia-reperfusion injury (IRI) is unknown. We sought to determine whether activation of macrophage adenosine 2A (A(2A)) receptors (A(2A)Rs) mediates tissue protection. We subjected C57Bl/6 mice infused with clodronate [dichloromethylene bisphosphonate (Cl(2)MBP)] to IRI (32 min of ischemia followed by 24 h of reperfusion) to deplete them of macrophages. IRI induced an elevation of plasma creatinine that was reduced with Cl(2)MBP (26% of control). Adoptive transfer of murine RAW 264.7 cells reconstituted injury, an effect blocked significantly by A(2A) agonists (27% of plasma creatinine from mice reconstituted with macrophages). Macrophages subjected to A(2A) knockout by small interfering RNA were adoptively transferred to macrophage-depleted mice and reconstituted injury (110% of control mice); however, the increase in plasma creatinine was blocked by A(2A) agonists (20% of vehicle treatment). Finally, the A(2A) agonist effect on IRI was blocked in macrophage-depleted A(2A)-knockout mice reconstituted with wild-type RAW 264.7 cells. RNase protection assays 24 h after IRI demonstrated that macrophages are required for IL-6 and TGF-beta mRNA induction. However, A(2A) agonist-mediated tissue protection is independent of IL-6 and TGF-beta mRNA. We conclude that the full extent of IRI requires macrophages and that A(2A) agonist-mediated tissue protection is independent of activation of macrophage A(2A)Rs.

Ischemia-reperfusion (I/R) injury occurs as a result of restoring blood flow to previously hypoperfused vessels or after tissue transplantation and is characterized by inflammation and microvascular occlusion. We report here that 4-[3-[6-amino-9-(5-ethylcarbamoyl-3,4-dihydroxy-tetrahydro-furan-2-yl)-9H-purin-2-yl]-prop-2-ynyl]-cyclohexanecarboxylic acid methyl ester (ATL146e), a selective agonist of the A(2A) adenosine receptor (A(2A)AR), profoundly protects mouse liver from I/R injury when administered at the time of reperfusion, and protection is blocked by the antagonist ZM241385. ATL146e lowers liver damage by 90% as assessed by serum glutamyl pyruvic transaminase and reduces hepatic edema and MPO. Most protection remains if ATL146e treatment is delayed for 1 h but disappears when delayed for 4 h after the start of reperfusion. In mice lacking the A(2A)AR gene, protection by ATL1465e is lost and ischemic injury of short duration is exacerbated compared with wild-type mice, suggesting a protective role for endogenous adenosine. I/R injury causes induction of hepatic transcripts for IL-1alpha, IL-1beta, IL-1Ra, IL-6, IL-10, IL-18, INF-beta, INF-gamma, regulated on activation, normal T cell expressed, and presumably secreted (RANTES), major intrinsic protein (MIP)-1alpha, MIP-2, IFN-gamma-inducible protein (IP)-10, and monocyte chemotactic protein (MCP)-1 that are suppressed by administering ATL146e to wild-type but not to A(2A)AR knockout mice. RANTES, MCP-1, and IP-10 are notable as induced chemokines that are chemotactic to T lymphocytes. The induction of cytokines may contribute to transient lymphopenia and neutrophilia that occur after liver I/R injury. We conclude that most damage after hepatic ischemia occurs during reperfusion and can be blocked by A(2A)AR activation. We speculate that inhibition of chemokine and cytokine production limits inflammation and contributes to tissue protection by the A(2A)AR agonist ATL146e.

Lysophosphatidic acid (LPA) released during ischemia has diverse physiological effects via its G protein-coupled receptors, LPA1, LPA2, and LPA3 (formerly Edg-2, -4, and -7). We tested the hypothesis that selective blockade of LPA receptors affords protection from renal ischemia-reperfusion (I/R) injury. By real-time PCR, LPA1-3 receptor mRNAs were expressed in mouse renal cortex, outer medulla, and inner medulla with the following rank order LPA3 = LPA2 > LPA1. In C57BL/6 mice whose kidneys were subjected to ischemia and reperfusion, treatment with a selective LPA3 agonist, oleoyl-methoxy phosphothionate (OMPT), enhanced injury. In contrast, a dual LPA1/LPA3-receptor antagonist, VPC-12249, reduced I/R injury, but this protective effect was lost when the antagonist was coadministered with OMPT. Interestingly, delaying administration of VPC-12249 until 30 min after the start of reperfusion did not alter its efficacy significantly. We conclude that VPC-12249 reduces renal I/R injury predominantly by LPA3 receptor blockade and could serve as a novel compound in the treatment of ischemia acute renal failure.

The role of monocytes/macrophages in the pathogenesis of ischemia-reperfusion injury ORB is unknown. We sought to determine whether activation of macrophage adenosine 2A (A2A) receptors (A2ARs) mediates tissue protection We subjected C57B1/6 mice infused with clodronate [dichloromethylene bisphosphonate (Cl2MBP)] to IRI (32 min of ischemia followed by 24 h of reperfusion) to deplete them of macrophages. IRI induced an elevation of plasma creatinine that was reduced with Cl2MBP (26% of control). Adoptive transfer of murine RAW 264.7 cells reconstituted injury, an effect blocked significantly by A2A agonists (27% of plasma creatinine from mice reconstituted with macrophages). Macrophages subjected to A2A knockout by small interfering RNA were adoptively transferred to macrophage-depleted mice and reconstituted injury (110% of control mice); however, the increase in plasma creatinine was blocked by A2A agonists (20% of vehicle treatment). Finally, the A2A agonist effect on IRI was blocked in macrophage-depleted A2A-knockout mice reconstituted with wild-type RAW 264.7 cells. RNase protection assays 24 h after IRI demonstrated that macrophages are required for IL-6 and TGF-β mRNA induction. However, A2A agonist-mediated tissue protection is independent of IL-6 and TGF-β mRNA. We conclude that the full extent of IRI requires macrophages and that A2A agonist-mediated tissue protection is independent of activation of macrophage A2ARs. [ABSTRACT FROM AUTHOR]

Lysophosphatidic acid (LPA) released during ischemia has diverse physiological effects via its G protein-coupled receptors, LPA[sub 1], LPA[sub 2], and LPA[sub 3] (formerly Edg-2, -4, and -7). We tested the hypothesis that selective blockade of LPA receptors affords protection from renal ischemia-reperfusion (UR) injury. By real-time PCR, LPA[sub 1-3] receptor mRNAs were expressed in mouse renal cortex, outer medulla, and inner medulla with the following rank order LPA[sub 3] = LPA[sub 2] > LPA[sub 1]. In C57BL/6 mice whose kidneys were subjected to ischemia and reperfusion, treatment with a selective LPA3 agonist, oleoyl-methoxy phosphothionate (OMPT), enhanced injury. In contrast, a dual LPA[sub 1]/LPA[sub 3]-receptor antagonist, VPC-12249, reduced UR injury, but this protective effect was lost when the antagonist was coadministered with OMPT. Interestingly, delaying administration of VPC-12249 until 30 min after the start of reperfusion did not alter its efficacy significantly. We conclude that VPC-12249 reduces renal I/R injury predominantly by LPA3 receptor blockade and could serve as a novel compound in the treatment ofischemia acute renal failure. [ABSTRACT FROM AUTHOR]

Investigates whether selective alpha2A adenosine receptor activation reduces ischemia-reperfusion injury in the rat kidney. Effect of adenosine on neutrophils and endothelial cells; Reduction in tubular injury and ischemic necrosis after ischemia-reperfusion injury following treatment with the adenosine analog DWH-146e.