Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42345 (mTOR)
 26,049 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Renal transplant patients lose their grafts most frequently from chronic allograft nephropathy and their lives from cardiac disease, malignancy, and infection. These are thus the challenges for renal transplant programs for this decade, just as acute rejection was the challenge of the last two decades. Most immunosuppressive protocols aim to minimize acute allograft rejection through heavy induction strategies and powerful but toxic maintenance therapies, counterbalanced by powerful and expensive infection prophylaxis. However, while the short-term results have improved steadily from the 1980s, and despite all the current efforts, the long-term success rates of renal transplants have not improved. Future aims include controlling both rejection and the long-term consequences of toxicity and infection risk. The biological facts that have determined our approach to the use of immunosuppressants have required us to try to balance the conflicting need for control of the allograft response and the inevitable toxicities of our drugs. The early period after transplantation requires maximum immunosuppressive efficacy with minimal ischemia reperfusion and good surgical-related wound healing. The latter period after transplantation requires less immunosuppressive efficacy and avoidance of chronic nephrotoxicity, cardiovascular, and malignancy risk factors. This usually leads to an induction strategy using a biological agent; a calcineurin inhibitor; an antiproliferative agent; and variable use of corticosteroids. In the long term, there are a variety of strategies for dose reduction or elimination of calcineurin inhibitors, incorporation of mammalian target of rapamycin inhibitors, and variable approaches to the risks of continued low-dose corticosteroids. The multiplicity of alternative strategies available testifies to the absence of evidence for a single dominant protocol and the urgent need to determine the relevant early indicators for measuring long-term success.
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PMID:Addressing the challenges for improving long-term outcomes in renal transplantation. 1910 Sep

Growth hormone (GH) and IGF-I have been implicated in the pathogenesis of type I diabetic (DM) nephropathy. We investigated renal GH receptor (GHR) and IGF-type 1 receptor (IGF1R) signaling in an animal model of type I DM. Kidney tissue was examined for GHR and IGF1R key signaling molecules. GHR levels were unchanged and IGF-I mRNA levels were decreased in the diabetic group (D). Basal and GH stimulated phosphorylated (p-) JAK2 and STAT5 levels were similar in controls (C) and D. The levels of p-IGF1R were similar in the two groups at baseline, while pAkt, pGSK3, p-mTOR, p-rpS6, p-erk1/2 (Mapk), and pSTAT-3 were increased in D. Following IGF-I administration p-Akt, p-rpS6, p-Mapk, and p-GSK levels increased more pronouncedly in D versus C. In conclusion, the lack of JAK2-STAT5 activation and the decrease in kidney IGF-I mRNA levels in D argue against a role for the GH activated JAK2-STAT5 pathway in the pathogenesis of diabetic nephropathy. On the other hand while IGF1R phosphorylation was unchanged, Akt/mTOR and MAPK signaling were hyperactivate in DM, suggesting their involvement. The increase in baseline activated Akt, mTOR, rpS6, and MAPK cannot be explained by activation of the IGF1R, but may be triggered by other growth factors and nutrients.
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PMID:Increased renal Akt/mTOR and MAPK signaling in type I diabetes in the absence of IGF type 1 receptor activation. 1938 75

Diabetic nephropathy (DN) associated with type 2 diabetes is the most common cause of end-stage renal disease (ESRD) and a serious health issue in the world. Currently, molecular basis for DN has not been established and only limited clinical treatments are effective in abating the progression to ESRD associated with DN. Here we found that diabetic db/db mice which lack the leptin receptor signaling can be used as a model of ESRD associated with DN. We demonstrated that p70S6-kinase was highly activated in mesangial cells in diabetic obese db/db mice. Furthermore, systemic administration of rapamycin, a specific and potent inhibitor of mTOR, markedly ameliorated pathological changes and renal dysfunctions. Moreover, rapamycin treatment shows a significant reduction in fat deposits and attenuates hyperinsulinemia with few side effects. These results indicate that mTOR activation plays a pivotal role in the development of ESRD and that rapamycin could be an effective therapeutic agent for DN.
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PMID:The mTOR pathway is highly activated in diabetic nephropathy and rapamycin has a strong therapeutic potential. 1942 88

Responsible factors in progressive tubular dysfunction in chronic renal failure have not been fully identified. In the present study, we hypothesized that the mammalian target of rapamycin, mTOR, was a key molecule in the degenerative and progressive tubular damage in chronic renal failure. Everolimus, an mTOR inhibitor, was administered for 14 days in 5/6 nephrectomized (Nx) rats at 2 and 8 weeks after renal ablation. Marked activation of the mTOR pathway was found at glomeruli and proximal tubules in remnant kidneys of Nx rats. The reduced expression levels of the phosphorylated S6 indicated the satisfactory pharmacological effects of treatment with everolimus for 14 days. Everolimus suppressed the accumulation of smooth muscle alpha actin, infiltration of macrophages and expression of kidney injury molecule-1 in the proximal tubules. In addition, everolimus-treatment restored the tubular reabsorption of albumin, and had a restorative effect on the expression levels of membrane transporters in the polarized proximal tubular epithelium, when its administration was started at 8 weeks after Nx. These results indicate that the constitutively activated mTOR pathway in proximal tubules has an important role in the progressive tubular dysfunction, and that mTOR inhibitors have renoprotective effects to improve the proximal tubular functions in end-stage renal disease.
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PMID:mTOR inhibitor everolimus ameliorates progressive tubular dysfunction in chronic renal failure rats. 1966 Apr 39

The poor long-term graft survival rate counteracts the important advance that transplantation is for end-stage renal disease patients. This is mainly due to the employment of immunosuppression that inhibits nonspecifically the alloimmune response to avoid graft rejection, but, at the same time, brings a number of adverse effects leading to chronic rejection. Thus, the major goal in transplantation is to reach an absence of immune response towards donor alloantigens without the need of long-term immunosuppressant drugs. In recent years, regulatory T cells, mainly those with a CD4CD25FOXP3 phenotype (named as Tregs), have demonstrated an inhibitory effect on immune responses against donor alloantigens. As a consequence, they are a potential tool in the development of transplant tolerance in vivo. Most of the evidence comes from experimental models, although recent works address the role of Tregs in the clinical arena of transplantation. In such a setting, the coexistence of immunosuppression in almost 100% patients is an essential factor to consider. Recent findings show that different drugs favor the induction and maintenance of Tregs in renal transplant recipients. Among them, mammalian target of rapamycin inhibitors seem to better promote the development of Tregs at present. The present work reviews all the evidence published up to date about Tregs in human renal transplantation with a special focus on the effect of clinical protocols of immunosuppression.
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PMID:Regulatory T cells in renal transplantation and modulation by immunosuppression. 1966 59

Muscle wasting is a prominent feature of end-stage renal disease and is associated with muscle weakness and poor physical functioning. Potential reasons for muscle wasting include advancing age, sedentary behavior, inflammation, poor nutritional intake, androgen deficiency, oxidative stress, metabolic acidosis, and insulin resistance. Each of these conditions can be associated with decreased protein synthesis, increased protein degradation, or both. The primary muscle protein synthesis pathway is the insulin insulin-like growth factor-1/phosphatidyl inositol-3 kinase/Akt pathway, which results in the phosphorylation of the mammalian target of rapamycin and subsequent increased protein synthesis. The major protein degradation pathway is the ubiquitin-proteasome system. This review discusses the ways in which end-stage renal disease tips the balance of protein turnover towards catabolism and the mechanisms by which various interventions may work to mitigate wasting or even cause anabolism.
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PMID:Anabolic and catabolic mechanisms in end-stage renal disease. 1980 Nov 38

Renal interstitial fibrosis is a major determinant of renal failure in the majority of chronic renal diseases. Transforming growth factor-beta (TGF-beta) is the single most important cytokine promoting renal fibrogenesis. Recent in vitro studies identified novel non-smad TGF-beta targets including p21-activated kinase-2 (PAK2), the abelson nonreceptor tyrosine kinase (c-Abl), and the mammalian target of rapamycin (mTOR) that are activated by TGF-beta in mesenchymal cells, specifically in fibroblasts but less in epithelial cells. In the present studies, we show that non-smad effectors of TGF-beta including PAK2, c-Abl, Akt, tuberin (TSC2), and mTOR are activated in experimental unilateral obstructive nephropathy in rats. Treatment with c-Abl or mTOR inhibitors, imatinib mesylate and rapamycin, respectively, each blocks noncanonical (non-smad) TGF-beta pathways in the kidney in vivo and diminishes the number of interstitial fibroblasts and myofibroblasts as well as the interstitial accumulation of extracellular matrix proteins. These findings indicate that noncanonical TGF-beta pathways are activated during the early and rapid renal fibrogenesis of obstructive nephropathy. Moreover, the current findings suggest that combined inhibition of key regulators of these non-smad TGF-beta pathways even in dose-sparing protocols are effective treatments in renal fibrogenesis.
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PMID:Noncanonical TGF-beta pathways, mTORC1 and Abl, in renal interstitial fibrogenesis. 1984 71

The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that plays a pivotal role in mediating cell size and mass, proliferation, and survival. mTOR has also emerged as an important modulator of several forms of renal disease. mTOR is activated after acute kidney injury and contributes to renal regeneration and repair. Inhibition of mTOR with rapamycin delays recovery of renal function after acute kidney injury. Activation of mTOR within the kidney also occurs in animal models of diabetic nephropathy and other causes of progressive kidney disease. Rapamycin ameliorates several key mechanisms believed to mediate changes associated with the progressive loss of GFR in chronic kidney disease. These include glomerular hypertrophy, intrarenal inflammation, and interstitial fibrosis. mTOR also plays an important role in mediating cyst formation and enlargement in autosomal dominant polycystic kidney disease. Inhibition of mTOR by rapamycin or one of its analogues represents a potentially novel treatment for autosomal dominant polycystic kidney disease. Finally, inhibitors of mTOR improve survival in patients with metastatic renal cell carcinoma.
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PMID:The role of the mammalian target of rapamycin (mTOR) in renal disease. 1987 10

Herein we have reported the use of rapamycin in immunosuppressive treatment after renal transplantation as a therapy of choice in a patient with diagnosis of tuberous sclerosis complex (TSC). TSC is a genetic disorder, caused by mutations of TSC1 or TSC2 genes. Products of these genes, hamartin and tuberin, create a complex that inhibits mammalian target of rapamycin (mTOR), a key protein engaged in regulation of the cell cycle. Mutations of TSC genes lead to constitutive activation of mTOR resulting in uncontrolled proliferation, differentiation, and migration of cells. As a consequence malformations of many organs arise. We have presented a case of a 47-year-old female TSC patient with multisystem involvement (skin, brain, lungs, and kidneys), who developed end-stage renal disease ESRD due to angiomyolipomas with subsequent bilateral nephrectomy. At the age of 44 years, she started hemodialysis treatments and 10 months later underwent kidney transplantation. Immunosuppressive treatment included the mTOR inhibitor rapamycin. Since the patient was discharged from hospital, she has remained in good clinical condition with stable graft function. Clinical evaluation after 2 years treatment with rapamycin revealed significant regression of skin lesions. Brain, chest, and abdominal cavity computed tomography images remained stable. No complications of immunosuppressive treatment or TSC were observed. Experimental and clinical studies have confirmed that rapamycin exerts beneficial effects in TSC, providing a new therapeutic option. Therefore an immunosuppressive regimen with rapamycin should be considered as the treatment of choice after kidney transplantation among patients with TSC seeking to avoid development or progression of disease complications.
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PMID:Rapamycin as a therapy of choice after renal transplantation in a patient with tuberous sclerosis complex. 1991 66

Both glomerular and tubular lesions are characterized by a proliferative phenotype in HIV-associated nephropathy. We hypothesized that mammalian target of rapamycin (mTOR) contributes to the development of the HIVAN phenotype. Both glomerular and tubular epithelial cells showed enhanced expression of phospho (p)-mTOR in HIV-1 transgenic mice (Tgs). In addition, renal tissues of transgenic mice (RT-Tg) showed enhanced phosphorylation of p70S6 kinase and an associated diminished phosphorylation of eEF2. Moreover, RT-Tgs showed enhanced phosphorylation of 4EBP1 and eIF4B; these findings indicated activation of the mTOR pathway in RT-Tgs. To test our hypothesis, age- and sex-matched control mice and Tgs were administered either saline or rapamycin (an inhibitor of the mTOR pathway) for 4 weeks. Tgs receiving rapamycin not only showed inhibition of the mTOR-associated downstream signaling but also displayed attenuated renal lesions. RT-Tgs showed enhanced expression of hypoxia-inducible factor-alpha and also displayed increased expression of vascular endothelial growth factor; on the other hand, rapamycin inhibited RT-Tg expression of both hypoxia-inducible factor-alpha and vascular endothelial growth factor. We conclude that the mTOR pathway contributes to the HIVAN phenotype and that inhibition of the mTOR pathway can be used as a therapeutic strategy to alter the course of HIVAN.
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PMID:HIV-associated nephropathy: role of mammalian target of rapamycin pathway. 2058 Oct 56


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