kn-93 and Glomerulosclerosis--Focal-Segmental

We have found that calcium calmodulin kinase IV is increased in T cells, podocytes, and mesangial cells from patients with systemic lupus erythematosus, as well as in lupus-prone mice, podocytes of patients with focal segmental glomerulosclerosis, and in mice injected with doxorubicin. We showed that this accounts for aberrant T cell function and glomerular damage. Using nanoparticles (nlg) loaded with a small drug inhibitor of calcium calmodulin kinase IV and tagged with antibodies directed to CD4 we have been able to show inhibition of autoimmunity and lupus nephritis. Also, using nlg tagged with antibodies to nephrin, we showed suppression of nephritis in lupus-prone mice and of glomerular damage in mice exposed to doxorubicin. We propose the development of approaches to deliver drugs to cells in a targeted and precise manner.

Topics: Animals; Antibiotics, Antineoplastic; Benzylamines; Calcium-Calmodulin-Dependent Protein Kinase Type 4; CD4 Antigens; Disease Models, Animal; DNA Methylation; Doxorubicin; Drug Delivery Systems; Glomerulosclerosis, Focal Segmental; Humans; Lupus Erythematosus, Systemic; Lupus Nephritis; Membrane Proteins; Mice; Mice, Inbred MRL lpr; Molecular Targeted Therapy; Nanoparticles; Protein Kinase Inhibitors; Sulfonamides; T-Lymphocytes; T-Lymphocytes, Regulatory; Th17 Cells

Evidence has demonstrated that Ca(2+)/calmodulin-dependent protein kinase type IV (CaMKIV) contributes to altered cytokine production by promoting the production of inflammatory cytokines. This study aimed to explore the protective role and underlying mechanisms of CaMKIV inhibition in experimental nephrotic syndrome.. BALB/c mice received single intravenous injections of adriamycin (10 mg/kg) then were sacrificed at two, four and six weeks. In the second study, treatment with KN-93, a CaMKIV inhibitor, or vehicle administered via intraperitoneal injection was started five days after adriamycin injection. Functional and pathologic parameters, the presence of inflammatory infiltration and the expressions of pro-inflammatory cytokines were assessed.. The CaMKIV protein expression levels were upregulated in the mice with adriamycin nephropathy, which was significantly inhibited by KN-93 (p<0.01). As compared with the vehicle-treated controls, KN-93 treatment resulted in marked suppression of proteinuria and serum creatinine at week 6 (p<0.01), but not at two weeks after induction of the disease. KN-93 inhibited glomerulosclerosis and the development of tubulointerstitial lesions. The renal alpha-smooth muscle actin (α-SMA) expression was also significantly suppressed by KN-93 treatment at week 6 (p<0.01). Moreover, KN-93 inhibited the renal monocyte chemoattractant protein-1 (MCP-1) expression, paralleled by a reduction in the interstitial infiltration of macrophages and T-cells (p<0.01).. Our findings suggest that activation of CaMKIV signaling is involved in the progression of glomerular diseases with a proteinuric state. Our data therefore justify the development of small molecule CaMKIV inhibitors for the treatment of clinical nephrotic syndrome.

Topics: Actins; Animals; Benzylamines; Calcium-Calmodulin-Dependent Protein Kinase Type 4; Chemokine CCL2; Cytokines; Disease Models, Animal; Doxorubicin; Drug Evaluation, Preclinical; Enzyme Induction; Glomerulosclerosis, Focal Segmental; Kidney; Macrophages; Male; Mice; Mice, Inbred BALB C; Nephritis, Interstitial; Nephrotic Syndrome; Protein Kinase Inhibitors; Proteinuria; Sulfonamides; T-Lymphocytes; Transforming Growth Factor beta; Up-Regulation

Mutations in the canonical transient receptor potential channel TRPC6 lead to an autosomal dominant form of human kidney disease characterized histologically by focal and segmental glomerulosclerosis. Several of these mutations enhance the amplitude and duration of the channel current. However, the effect of these mutations on the downstream target of TRPC6, the nuclear factor of activated T cell (NFAT) transcription factors, has not been previously examined. Here we demonstrate that all three TRPC6 mutations previously shown to enhance channel activity lead to enhanced basal NFAT-mediated transcription in several cell lines, including cultured podocytes. These effects are dependent on channel activity and are dominant when mutants are coexpressed with wild-type TRPC6. While TRPC6 mutants do not demonstrate an increase in basal channel currents, a subset of cells expressing the R895C and E897K mutants have elevated basal calcium levels as measured by Fura-2 imaging. Activation of NFAT by TRPC6 mutants is blocked by inhibitors of calcineurin, calmodulin-dependent kinase II, and phosphatidylinositol 3-kinase. PP2 partially inhibits NFAT activation by mutant TRPC6 independently of Src, Yes, or Fyn. Differences in channel glycosylation and surface expression do not explain the ability of mutants to enhance NFAT activation. Taken together, these results identify the activation of the calcineurin-NFAT pathway as a potential mediator of focal segmental glomerulosclerosis.

Topics: Benzylamines; Calcineurin; Calcineurin Inhibitors; Calcium; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Cell Line; Cell Membrane; Chromones; Cyclosporine; Enzyme Inhibitors; Glomerulosclerosis, Focal Segmental; Glycosylation; Humans; Membrane Potentials; Morpholines; Mutation; NFATC Transcription Factors; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Podocytes; Protein Processing, Post-Translational; Receptor, Muscarinic M1; RNA, Messenger; Signal Transduction; Sulfonamides; Transcription, Genetic; Transfection; TRPC Cation Channels; TRPC6 Cation Channel