Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

FK506 (tacrolimus) is an immunosuppressive drug which interrupts Ca2+-calmodulin-calcineurin signaling pathways in T lymphocytes, thereby blocking antigen activation of T cell early activation genes. Regulation of insulin gene expression in the beta cell may also involve Ca2+-signaling pathways and FK506 has been associated with insulin-requiring diabetes mellitus during clinical use. The purpose of this study was to characterize the effects of FK506 on human insulin gene transcription, insulin mRNA levels, and insulin secretion using as a model the HIT-T15 beta cell line. FK506 had no acute effect on insulin secretion in the HIT cell, but caused a reversible time- and dose-dependent (10(-9)-10(-6) M) decrease in HIT cell insulin secretion. Decreased insulin secretion in the presence of FK506 was also accompanied by a dose-dependent decrease in HIT cell insulin content, insulin mRNA levels, and expression of a human insulin promoter-chloramphenicol acetyl transferase (CAT) reporter gene. FK506 decreased HIT cell expression of the human insulin promoter-CAT reporter gene by 40% in the presence of both low (0.4 mM) at high (20 mM) glucose concentrations. Western blot analysis of HIT cell proteins gave evidence for the presence of calcineurin in the HIT cell. These findings suggest that FK506 may have direct effects to reversibly inhibit insulin gene transcription, leading to a decline in insulin mRNA levels, insulin synthesis, and ultimately insulin secretion.
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PMID:Effects of tacrolimus (FK506) on human insulin gene expression, insulin mRNA levels, and insulin secretion in HIT-T15 cells. 898 25

Bioactive compound(s) extracted from cinnamon potentiate insulin activity, as measured by glucose oxidation in the rat epididymal fat cell assay. Wortmannin, a potent PI 3'-kinase inhibitor, decreases the biological response to insulin and bioactive compound(s) from cinnamon similarly, indicating that cinnamon is affecting an element(s) upstream of PI 3'-kinase. Enzyme studies done in vitro show that the bioactive compound(s) can stimulate autophosphorylation of a truncated form of the insulin receptor and can inhibit PTP-1, a rat homolog of a tyrosine phosphatase (PTP-1B) that inactivates the insulin receptor. No inhibition was found with alkaline phosphate or calcineurin suggesting that the active material is not a general phosphatase inhibitor. It is suggested, then, that a cinnamon compound(s), like insulin, affects protein phosphorylation-dephosphorylation reactions in the intact adipocyte. Bioactive cinnamon compounds may find further use in studies of insulin resistance in adult-onset diabetes.
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PMID:Regulation of PTP-1 and insulin receptor kinase by fractions from cinnamon: implications for cinnamon regulation of insulin signalling. 976 7

Daclizumab and basiliximab, engineered human IgG monoclonal antibodies to the interleukin-2 (IL-2) receptor alpha-subunit, were approved to prevent acute rejection after renal transplantation. Daclizumab was studied in adult and pediatric renal allograft recipients, liver allograft recipients, and calcineurin-sparing protocols in renal transplant recipients. Basiliximab was studied in renal allograft recipients and subgroups of recipients of living-related and cadaveric transplants, and in patients with diabetes mellitus. Both agents reduced acute rejection and were associated with few adverse effects. However, information regarding their long-term effects on infection, malignancy, chronic rejection, and patient survival must be available before a final decision is made regarding their proper administration. We propose that a likely role the drugs will play in the field of solid organ transplantation is in new protocols that allow sparing of other more toxic immunosuppressive agents.
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PMID:A review of interleukin-2 receptor antagonists in solid organ transplantation. 1051 62

In mouse pancreatic beta-cells, extracellular ATP (0.1 mmol/l) effectively reduced glucose-induced insulin secretion. This inhibitory action resulted from a direct interference with the secretory machinery, and ATP suppressed depolarization-induced exocytosis by 60% as revealed by high-resolution capacitance measurements. Suppression of Ca2+-dependent exocytosis was mediated via binding to P2Y1 purinoceptors but was not associated with inhibition of the voltage-dependent Ca2+ currents or adenylate cyclase activity. Inhibition of exocytosis by ATP resulted from G-protein-dependent activation of the serine/threonine protein phosphatase calcineurin and was abolished by cyclosporin A and deltamethrin. In contrast to the direct inhibitory action on exocytosis, ATP reduced the whole-cell ATP-sensitive K+ (K(ATP)) current by 30% (via activation of cytosolic phospholipase A2), leading to membrane depolarization and stimulation of electrical activity. The stimulatory effect of ATP also involved mobilization of Ca2+ from thapsigargin-sensitive intracellular stores. We propose that the inhibitory action of ATP, by interacting with the secretory machinery at a level downstream to an elevation in [Ca2+]i, is important for autocrine regulation of insulin secretion in mouse beta-cells.
Diabetes 1999 Nov
PMID:Multiple sites of purinergic control of insulin secretion in mouse pancreatic beta-cells. 1053 51

Cyclosporine and tacrolimus are potent inhibitors of the calcineurin-dependent cytokine synthesis in activated lymphocytes. In renal transplant patients tacrolimus is more powerful in preventing severe and refractory rejections, even when compared with the new cyclosporine microemulsion formulation. Both drugs are equally nephrotoxic, but tacrolimus induces less hypertension and less pronounced hyperlipidaemia. Especially in some categories of patients, a higher incidence of de-novo diabetes mellitus is seen with tacrolimus therapy.
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PMID:Which calcineurin inhibitor is preferred in renal transplantation: tacrolimus or cyclosporine? 1063 Aug 11

Post-transplant diabetes mellitus, a complication due to corticosteroids and the calcineurin inhibitors, cyclosporine and tacrolimus (FK506), is commonly regarded as a form of type-2 (adult-onset) diabetes mellitus. Diabetic ketoacidosis, which requires relative insulin deficiency to impair fatty acid metabolism, is a complication of type-1 diabetes mellitus. We report three patients who presented with diabetic ketoacidosis post-transplant. All three patients presented with severe hyperglycemia, significant ketosis and metabolic acidosis of variable severity. One patient was a renal transplant recipient on a cyclosporine-based regimen. The other two patients were liver transplant recipients receiving either cyclosporine or tacrolimus-based immunosuppression. Both of the liver transplant recipients were found to have moderate to high serum levels of calcineurin inhibitors on presentation. The liver recipient on cyclosporine (Neoral) had a 4 hour post-dose level of 388 ng/ml and the patient on tacrolimus was found to have a trough level of 21.2 ng/ml. Our experience suggests that post-transplant diabetes mellitus, in association with calcineurin inhibition, may result in ketoacidosis either secondary to relative beta cell dysfunction, peripheral insulin resistance, or a combination of the two effects. Post-transplant diabetes mellitus can be an atypical form of adult-onset diabetes with features of both type I and type II diabetes mellitus.
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PMID:Post-transplant diabetic ketoacidosis--a possible consequence of immunosuppression with calcineurin inhibiting agents: a case series. 1074 93

Despite recent advances in the prolongation of patient and graft survival, transplant patients continue to die prematurely of accelerated cardiovascular disease. Arterial hypertension is a well-known risk factor for cardiovascular disease morbidity and mortality in the general population and a frequent complication following transplantation. The pathogenesis of posttransplant hypertension in renal transplant recipients is multifactorial and includes pretransplant hypertension in the recipient, donor hypertension, uncontrolled renin secretion from the remaining native kidney, hypertension as a consequence of graft dysfunction, recurrent or de novo renal disease, and, nowadays more rarely, transplant artery stenosis. The strong impact of an immunosuppressive regimen consisting of calcineurin inhibitors and steroids must also be considered. Calcineurin inhibitors and corticosteroids induce hypertension in renal, cardiac, liver, bone marrow, and lung transplant recipients. Posttransplant hypertension appears to be a major risk factor for graft and patient survival. Recent controlled studies support the opinion that posttransplant hypertension must be treated as strictly as in a population with essential hypertension, diabetes mellitus, or chronic renal failure.
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PMID:Management strategies for posttransplant hypertension. 1115 34

Post-transplant diabetes mellitus (PTDM) is one of the feared complications of immunosuppressive therapy. Despite advances, including the introduction of the steroid-sparing calcineurin inhibitors, cyclosporine and tacrolimus, the incidence rate remains greater than 10% to 30%, especially in minority populations. PTDM increases the subsequent risk of both graft loss and patient death, and predisposes patients to all complications of diabetes, including retinopathy and neuropathy. Patients should be monitored closely, especially during the first 3 months post-transplant, and treated aggressively, should glucose intolerance be detected. Minimization of immunosuppression dose, diet, oral hypoglycemic agents, and insulin have all been used in the treatment of PTDM, however, the insulin-sensitizing agents have not been studied. It is hoped that newer immunosuppressive regimens and, ultimately, the ability to achieve tolerance will eventually solve the problem of PTDM.
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PMID:Post-transplant diabetes: incidence, relationship to choice of immunosuppressive drugs, and treatment protocol. 1117 28

Imidazoline compounds have been considered for the treatment of type 2 diabetes. We have now investigated the effects of imidazolines on interleukin (IL)-1beta-induced beta-cell apoptosis and the signal transduction pathways involved. Inhibition of Ca2+ influx into beta-cells by D-600, a blocker of voltage-gated L-type Ca2+ channels, suppressed IL-1beta-induced apoptosis. Our data show that calcineurin, Ca2+/calmodulin-dependent serine/threonine protein phosphatase 2B, is responsible for the effect of Ca2+ on beta-cell apoptosis. We also demonstrate that IL-1beta-mediated apoptosis correlates with expression of inducible nitric oxide synthase (iNOS) and the increase in intracellular production of nitric oxide. An inhibitor of cGMP-dependent protein kinase (PKG), KT5823, suppressed IL-1beta-induced apoptosis, suggesting the involvement of a PKG-dependent pathway in the apoptotic process. One of the major findings in this study is that imidazoline compounds RX871024 and efaroxan, suggested as prototypes of a new generation of drugs against type 2 diabetes, can protect against IL-1beta-induced apoptosis in pancreatic beta-cells, possibly by their inhibition of the expression of iNOS, a key element in the IL-1beta-induced apoptotic pathway in pancreatic beta-cells. These data suggest that imidazoline compounds should be explored as a potential therapeutic agent for the treatment of both type 1 and type 2 diabetes.
Diabetes 2001 Feb
PMID:Imidazoline compounds protect against interleukin 1beta-induced beta-cell apoptosis. 1127 6

Protein tyrosine phosphatase 1B (PTP1B) attenuates insulin signaling by catalyzing dephosphorylation of insulin receptors (IR) and is an attractive target of potential new drugs for treating the insulin resistance that is central to type II diabetes. Several analogues of cholecystokinin(26)(-)(33) (CCK-8) were found to be surprisingly potent inhibitors of PTP1B, and a common N-terminal tripeptide, N-acetyl-Asp-Tyr(SO(3)H)-Nle-, was shown to be necessary and sufficient for inhibition. This tripeptide was modified to reduce size and peptide character, and to replace the metabolically unstable sulfotyrosyl group. This led to the discovery of a novel phosphotyrosine bioisostere, 2-carboxymethoxybenzoic acid, and to analogues that were >100-fold more potent than the CCK-8 analogues and >10-fold selective for PTP1B over two other PTP enzymes (LAR and SHP-2), a dual specificity phosphatase (cdc25b), and a serine/threonine phosphatase (calcineurin). These inhibitors disrupted the binding of PTP1B to activated IR in vitro and prevented the loss of tyrosine kinase (IRTK) activity that accompanied PTP1B-catalyzed dephosphorylation of IR. Introduction of these poorly cell permeant inhibitors into insulin-treated cells by microinjection (oocytes) or by esterification to more lipophilic proinhibitors (3T3-L1 adipocytes and L6 myocytes) resulted in increased potency, but not efficacy, of insulin. In some instances, PTP1B inhibitors were insulin-mimetic, suggesting that in unstimulated cells PTP1B may suppress basal IRTK activity. X-ray crystallography of PTP1B-inhibitor complexes revealed that binding of an inhibitor incorporating phenyl-O-malonic acid as a phosphotyrosine bioisostere occurred with the mobile WPD loop in the open conformation, while a closely related inhibitor with a 2-carboxymethoxybenzoic acid bioisostere bound with the WPD loop closed, perhaps accounting for its superior potency. These CCK-derived peptidomimetic inhibitors of PTP1B represent a novel template for further development of potent, selective inhibitors, and their cell activity further justifies the selection of PTP1B as a therapeutic target.
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PMID:Small molecule peptidomimetics containing a novel phosphotyrosine bioisostere inhibit protein tyrosine phosphatase 1B and augment insulin action. 1134 29


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