Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.4 (ribonuclease)
 6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Binding of the P-, L-, and E-selectins to sialyl Lewis(x) (sLe(x)) retards circulating leukocytes, thereby facilitating their attachment to the blood vessels of allografts. Whether the selectin inhibitor bimosiamose (BIMO; C(46)H(54)O(16) . 0.25 H(2)O [867.4 molecular weight]) inhibits the rejection process of kidney allografts in a rat model was examined. Rat recipients acutely rejected kidney allografts at a mean survival time of 8.8 +/- 0.75 d. An intravenous 7-d infusion by osmotic pump of 2.5, 5, 10, or 20 mg/kg BIMO extended kidney allograft survival to 11.5 +/- 2.2 d (P < 0.03), 25.4 +/- 11.4 d (P < 0.006), 37.4 +/- 13.6 d (P < 0.001), and 39.8 +/- 34.5 d (P < 0.01), respectively. Combination of BIMO with cyclosporine produced synergistic interactions, as documented by the combination index (CI) values of 0.34 to 0.43 (CI <1 is synergistic; CI = 1 is additive; and CI >1 is antagonistic). Similarly, BIMO interacted synergistically with sirolimus (CI = 0.64) and FTY720 (CI = 0.22). While the mechanism of immunosuppression was being analyzed, decreased infiltration of CD4(+), CD8(+), and macrophages on day 7 after grafting was observed. Multiple cytokines were also expressed, including IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-10, IL-12, IL-18, TNF-alpha, and IFN-gamma in kidney allografts on days 3, 5, and 7 after grafting, as measured by a ribonuclease protection assay. Furthermore, at similar time points, BIMO treatment reduced intragraft expression of P-selectin glycoprotein ligand-1, CX(3)CL1, CCL19, CCL20, and CCL2. Thus, BIMO blocks allograft rejection by reduction of intragraft expression of cytokines and chemokines.
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PMID:Selectin inhibitor bimosiamose prolongs survival of kidney allografts by reduction in intragraft production of cytokines and chemokines. 1550 42

HIV-associated dementia (HAD) correlates with infiltration of monocytes into the brain. The accessory HIV-1 negative factor (Nef) protein, which modulates several signaling pathways, is constitutively present in persistently infected astroctyes. We demonstrated that monocytes responded with chemotaxis when subjected to cell culture supernatants of nef-expressing astrocytic U251MG cells. Using a protein array, we identified CC chemokine ligand 2/monocyte chemotactic protein-1 (CCL2/MCP-1) as a potential chemotactic factor mediating this phenomenon. CCL2/MCP-1 upregulation by Nef was further confirmed by ribonuclease protection assay, RT-PCR and ELISA. By applying neutralizing antibodies against CCL2/MCP-1 and using CCR2-deficient monocytes, we confirmed CCL2/MCP-1 as the exclusive factor secreted by nef-expressing astrocytes capable of attracting monocytes. Additionally, we showed that Nef-induced CCL2/MCP-1 expression depends on the myristoylation moiety of Nef and requires functional calmodulin. In summary, we suggest that Nef-induced CCL2/MCP-1 expression in astrocytes contributes to infiltration of monocytes into the brain, and thereby to progression of HAD.
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PMID:HIV-1 Nef upregulates CCL2/MCP-1 expression in astrocytes in a myristoylation- and calmodulin-dependent manner. 1704 94

Chemokines promote tumour progression by enhancing proliferation and modifying the immune response. The purpose of this study was to test the hypothesis that CCL2 monocyte chemotactic protein-1 (MCP-1) contributes to the progression of colorectal cancer by influencing the number and distribution of tumour associated macrophages (TAMs). Chemokine expression was assessed in human colorectal adenocarcinomas by ribonuclease protection assay (RPA). Colonic adenocarcinoma cell lines were used to assess chemokine production by enzyme linked immunosorbant assay (ELISA), and Boyden microchemotaxis assays were performed to determine cell line supernatant monocyte chemotactic activity. CCL2 production was assessed in paraffin embedded tumour samples by immunohistochemistry. Finally, the number of macrophages and their distribution was determined in the same colorectal adenocarcinomas and compared with CCL2 expression and tumour stage. Results showed that CCL2 produced by cell lines induced monocyte chemoattraction, the expression of this chemokine in solid cancers increased with tumour stage (P < 0.05) and immunohistochemistry localized production to tumour cells. Analysis of the macrophage infiltrate showed that the accumulation was significantly greater in tumours than controls (P < 0.005) and within tumours it was greatest in necrotic regions (median 44,600 per mm(3)). Macrophage accumulation increased with tumour stage and correlated with CCL2 expression (r(s) = 0.8). CXCL8 interleukin 8 (IL-8), a potent angiogenic factor and growth factor, was expressed in all tumours and cell lines. It is concluded that CCL2 induces the accumulation of tumour promoting TAMs in human colorectal cancer and represents a therapeutic target to modify the macrophage response and direct immune mediated therapy.
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PMID:Chemokine expression is associated with the accumulation of tumour associated macrophages (TAMs) and progression in human colorectal cancer. 1739 Jan 11

Effects in the liver of fatal intoxication with the binary toxin ricin are unclear. We report a robust neutrophil influx into the liver of C57BL/6 mice after lethal parenteral ricin challenge, occurring in peri-portal and centro-lobular hepatic areas within 2 h, followed by the abrupt disappearance of hepatic macrophages/Kupffer cells. Chemokine profiles determined by microarray, ribonuclease protection assays, northern blotting, and enzyme-linked immunosorbent assays showed rapid (2 h) upregulation and persistence of those for neutrophils (CXCL1/KC, CXCL2/MIP-2) and monocytes (CCL2/MCP-1). Red blood cell pooling (8-12 h), loss of hepatocyte glycogen (8-48 h) associated with progressive hypoglycemia, fibrin deposition (24-48 h), and death (72-96 h) followed. Monoclonal antibody to ricin A chain, administered intravenously, blunted hypoglycemia, and abrogated death. This outcome was observed when anti-ricin antibody was given before toxin exposure as well as when administered approximately 10 h after toxin exposure. Targeting antibody to specific amino-acid sequences on the ricin A chain (HAEL and QXXWXXA) was critical to the therapeutic effect. Re-emergence of liver macrophages/Kupffer cells and replenishment of glycogen in previously depleted hepatocytes preceded full recovery of the host. These data identify critical events for liver injury and healing in ricin intoxication, as well as a new means and specific targets for post-exposure therapeutic intervention.
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PMID:Post-exposure targeting of specific epitopes on ricin toxin abrogates toxin-induced hypoglycemia, hepatic injury, and lethality in a mouse model. 1877 82