pyrimidinones and Proteinuria

Transforming growth factor-β (TGF-β) plays crucial roles in the development of focal segmental glomerulosclerosis, but key molecular pathways remain unknown. Here, we identified the regulation of mammalian target of rapamycin complex1 (mTORC1) by TGF-β via ERK1/2 in the Adriamycin-induced murine model of focal segmental glomerulosclerosis. Adriamycin administration elicited early activation of TGF-β-ERK1/2-mTORC1 in podocytes, which persisted at later stages of albuminuria and glomerulosclerosis. Phosphorylation of the TGF-β receptor-I (TGF-βRI), Smad3, ERK1/2 and ribosomal protein S6 were evident in the glomeruli of adriamycin-treated mice. Targeting TGFβ-RI and mTORC1 with pharmacological inhibitors suppressed TGF-β signaling in glomeruli and significantly reduced albuminuria, glomerulosclerosis, protein levels of collagen 4α3, plasminogen activator inhibitor-1, and vimentin and restored mRNA levels of podocyte markers. Low dose US Food and Drug Administration (FDA)-approved MEK/ERK inhibitor trametinib/GSK1120212 blunted TGF-β1-induced mTORC1 activation in podocytes, ameliorated up-regulation of TGF-β, plasminogen activator inhibitor-1, monocyte chemoattractant protein-1, fibronectin and α-smooth muscle actin and prevented albuminuria and glomerulosclerosis with improved serum albumin. In cultured podocytes, this pathway was found to be associated with translation of fibrogenic collagen 4α3 and plasminogen activator inhibitor-1, without influencing their transcription. Notably, rapamycin suppressed upstream p-TGF-βRI, p-Smad3 and p-ERK1/2, and trametinib down-regulated upstream p-Smad3 in ex vivo and in vivo studies, indicating that harmful paracrine signaling among glomerular cells amplified the TGF-β-ERK1/2-mTORC1 axis by forming a positive feedback loop. Thus, an accentuated TGF-β-ERK1/2-mTORC1 pathway is suggested as a central upstream mediator to develop proteinuria and glomerulosclerosis. Hence, preventing activation of this vicious loop by trametinib may offer a new therapeutic strategy for glomerular disease treatment.

Topics: Animals; Cell Line; Disease Models, Animal; Doxorubicin; Drug Evaluation, Preclinical; Glomerulosclerosis, Focal Segmental; Humans; Kidney Glomerulus; Male; MAP Kinase Signaling System; Mechanistic Target of Rapamycin Complex 1; Mice; Phosphorylation; Proteinuria; Pyridones; Pyrimidinones; Rats; Transforming Growth Factor beta

Activation of the renin-angiotensin system (RAS) plays an essential role in the pathogenesis of CKD and cardiovascular disease. However, current anti-RAS therapy only has limited efficacy, partly because of compensatory upregulation of renin expression. Therefore, a treatment strategy to simultaneously target multiple RAS genes is necessary to achieve greater efficacy. By bioinformatics analyses, we discovered that the promoter regions of all RAS genes contained putative T-cell factor (TCF)/lymphoid enhancer factor (LEF)-binding sites, and β-catenin induced the binding of LEF-1 to these sites in kidney tubular cells. Overexpression of either β-catenin or different Wnt ligands induced the expression of all RAS genes. Conversely, a small-molecule β-catenin inhibitor ICG-001 abolished RAS induction. In a mouse model of nephropathy induced by adriamycin, either transient therapy or late administration of ICG-001 abolished established proteinuria and kidney lesions. ICG-001 inhibited renal expression of multiple RAS genes in vivo and abolished the expression of other Wnt/β-catenin target genes. Moreover, ICG-001 therapy restored expression of nephrin, podocin, and Wilms' tumor 1, attenuated interstitial myofibroblast activation, repressed matrix expression, and inhibited renal inflammation and fibrosis. Collectively, these studies identify all RAS genes as novel downstream targets of Wnt/β-catenin. Our results indicate that blockade of Wnt/β-catenin signaling can simultaneously repress multiple RAS genes, thereby leading to the reversal of established proteinuria and kidney injury.

Topics: Albumins; Animals; beta Catenin; Binding Sites; Bridged Bicyclo Compounds, Heterocyclic; Cell Line; Computational Biology; Creatinine; Disease Models, Animal; Gene Expression Regulation; Humans; Kidney; Kidney Tubules; Ligands; Mice; Mice, Inbred BALB C; Podocytes; Promoter Regions, Genetic; Proteinuria; Pyrimidinones; ras Proteins; Renin-Angiotensin System; Wnt Signaling Pathway

It is still difficult to manage chronic glomerulonephritis with corticosteroids because of safety concerns, especially for patients with mild symptoms and infants. Therefore, an alternative approach is greatly required. Pemirolast potassium (CAS 100299-08-9) is an antiallergic drug with high safety.. Two glomerulonephritis rat models were prepared to examine the pharmacological actions of pemirolast potassium: one reversible model prepared with the anti-Thy-1 antibody, and another irreversible model by unilateral nephrectomy and with the anti-Thy-1 antibody. Pemirolast potassium was administered to 10 Japanese chronic glomerulonephritis patients concurrently affected by allergic rhinitis in order to examine its efficacy for mild proteinuria.. Pemirolast potassium 1 and 10 mg/kg markedly inhibited proteinuria in the reversible model. In the irreversible model, pemirolast potassium 3 mg/kg showed a significant decrease in the incidence of glomerulosclerosis. In chronic glomerulonephritis patients, pemirolast potassium, 10 mg twice daily, for 6 months, significantly reduced the severity of proteinuria.. Our research suggested the efficacy of pemirolast potassium in glomerulonephritis. A well-controlled study is considered necessary to validate pemirolast potassium as a therapeutic drug for glomerulonephritis.

Topics: Adolescent; Adult; Animals; Anti-Allergic Agents; Autoantibodies; Disease Models, Animal; Female; Glomerulonephritis; Histamine Antagonists; Humans; Kidney; Male; Middle Aged; Nephrectomy; Pilot Projects; Proteinuria; Pyridines; Pyrimidinones; Rats; Rats, Sprague-Dawley; Rats, Wistar; Rhinitis, Allergic, Seasonal; Thyroid Gland

Topics: Adult; Aged; Cross-Sectional Studies; Endothelium, Vascular; Female; HIV; HIV Infections; HIV Protease Inhibitors; Humans; Lopinavir; Male; Nitroglycerin; Pilot Projects; Proteinuria; Pyrimidinones; Regional Blood Flow; Ritonavir; Vasodilation