Calcineurin A-β is required for hypertrophy but not matrix expansion in the diabetic kidney

Reddy, Ramesh N.; Knotts, Taylor; Roberts, Brian R.; Molkentin, Jeffery D.; Price, S. Russ; Gooch, Jennifer

doi:10.1111/j.1582-4934.2009.00910.x

Cited by 17 publications

(18 citation statements)

References 28 publications

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“…Our results are in line with previous studies, showing that the inhibition of calcineurin reduced renal hypertrophy and blocked glomerular hypertrophy in kidneys from diabetic rats [31]. In addition, whole kidney and glomerular hypertrophy were also reduced in diabetic calcineurin A-β knockout mice [32]. It may be concluded that the insulin-TRPC6-calcium/calmodulin-calcineurin-nuclear factor of activated T cells-pathway may be important for the pathogenesis of diabetic nephropathy.…”

Section: Discussionsupporting

confidence: 82%

Insulin Increases Expression of TRPC6 Channels in Podocytes by a Calcineurin-Dependent Pathway

Xia

Liu

et al. 2016

Cell Physiol Biochem

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Background/Aims: Insulin signaling to podocytes is relevant for the function of the glomerulus. Now, we tested the hypothesis that insulin increases the surface expression of canonical transient receptor potential canonical type 6 (TRPC6) channels in podocytes by a calcineurin-dependent pathway. Methods: We used quantitative RT-PCR, immunoblotting, immunofluorescence and fluorescence spectrophotometry in cultured podocytes. Activation of Nuclear Factor of Activated T-cells (NFATc1) was measured using a specific calorimetric assay. Results: Insulin increased the expression of TRPC6 transcripts and protein in podocytes. Insulin increased TRPC6 transcripts in a time and dose-dependent manner. The insulin-induced elevation of TRPC6 transcripts was blocked in the presence of tacrolimus, cyclosporine A, and NFAT-inhibitor (each p < 0.01 by ANOVA and Bonferroni's multiple comparison test). Transcripts of NOX4, another target gene of the calcineurin-NFAT pathway, were affected in a similar way. Immunoblotting showed that the administration of 100 nmol/L insulin increased TRPC6-proteins 2-fold within 48 hours. Insulin increased the activity of NFATc1 in nuclear extracts (p < 0.001) whereas tacrolimus, cyclosporine A, and NFAT-inhibitor blocked that insulin effect (p < 0.001; two way ANOVA). Immunofluorescence showed that insulin increased TRPC6-expression on the cell surface. Fluorescence-spectrophotometry and manganese quench experiments indicated that the increased TRPC6-expression after insulin administration was accompanied by an elevated transplasmamembrane cation influx. Insulin-stimulated surface expression of TRPC6 as well as transplasmamembrane cation influx could be reduced by pretreatment with tacrolimus. Conclusion: Insulin increases the expression of TRPC6 channels in podocytes by activation of the calcineurin-dependent pathway.

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Section: Discussionsupporting

confidence: 82%

Insulin Increases Expression of TRPC6 Channels in Podocytes by a Calcineurin-Dependent Pathway

Xia

Liu

et al. 2016

Cell Physiol Biochem

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“…Notably, Wada et al (43) reported that overexpression of constitutively active CnA␣ did not increase miR-23a expression. Since we and others (14,33) reported that NFAT is regulated by CnA␤, the other CnA catalytic subunit isoform in skeletal muscle, we overexpressed a constitutively active form of CnA␤ by adenoviral infection (CnA␤ AV) in C2C12 cells to test how it affected miR-23a. Similar to the findings of Wada et al, CnA␤ AV did not increase the level of miR-23a; however, it did prevent the Dex-induced suppression of miR-23a (Fig.…”

Section: Mir-23a and Cn/nfat Signaling Are Suppressed During Muscle Amentioning

confidence: 99%

miR-23a is decreased during muscle atrophy by a mechanism that includes calcineurin signaling and exosome-mediated export

Hudson

Woodworth‐Hobbs

Zheng

et al. 2014

American Journal of Physiology-Cell Physiology

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115

101

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Skeletal muscle atrophy is prevalent in chronic diseases, and microRNAs (miRs) may play a key role in the wasting process. miR-23a was previously shown to inhibit the expression of atrogin-1 and muscle RING-finger protein-1 (MuRF1) in muscle. It also was reported to be regulated by cytoplasmic nuclear factor of activated T cells 3 (NFATc3) in cardiomyocytes. The objective of this study was to determine if miR-23a is regulated during muscle atrophy and to evaluate the relationship between calcineurin (Cn)/NFAT signaling and miR-23a expression in skeletal muscle cells during atrophy. miR-23a was decreased in the gastrocnemius of rats with acute streptozotocin-induced diabetes, a condition known to increase atrogin-1 and MuRF1 expression and cause atrophy. Treatment of C2C12 myotubes with dexamethasone (Dex) for 48 h also reduced miR-23a as well as RCAN1.4 mRNA, which is transcriptionally regulated by NFAT. NFATc3 nuclear localization and the amount of miR-23a decreased rapidly within 1 h of Dex administration, suggesting a link between Cn signaling and miR-23a. The level of miR-23a was lower in primary myotubes from mice lacking the α- or β-isoform of the CnA catalytic subunit than wild-type mice. Dex did not further suppress miR-23a in myotubes from Cn-deficient mice. Overexpression of CnAβ in C2C12 myotubes prevented Dex-induced suppression of miR-23a. Finally, miR-23a was present in exosomes isolated from the media of C2C12 myotubes, and Dex increased its exosomal abundance. Dex did not alter the number of exosomes released into the media. We conclude that atrophy-inducing conditions downregulate miR-23a in muscle by mechanisms involving attenuated Cn/NFAT signaling and selective packaging into exosomes.

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“…CaNA-a was the predominant isoform expressed in the proximal tubules and was associated with ECM synthesis and TGF-b expression, 26,27 whereas the b-isoform was expressed mostly in glomeruli. Gooch et al 26 found that rats lacking a-isoform displayed renal developmental defects or fibrosis, which coincided with the side effects of CsA.…”

Section: Effects Of Can Sirna On Can Mrna and Protein Expression Of Hmentioning

confidence: 99%

Norcantharidin inhibits the expression of extracellular matrix and TGF-β1 in HK-2 cells induced by high glucose independent of calcineurin signal pathway

Chen

Liu

et al. 2011

Laboratory Investigation

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Norcantharidin (NCTD) was shown in our previous studies to attenuate renal tubulointerstitial fibrosis in rat models with diabetic nephropathy (DN). The aim of this study was to determine the effects of NCTD on the expression of extracellular matrix (ECM) and TGF-b1 in HK-2 cells stimulated by high glucose and on calcineurin (CaN)/NFAT pathway. Whether or not the antifibrotic effect of NCTD on renal interstitium was dependent on its inhibition of CaN pathway was also investigated. Experimental concentrations of NCTD were verified by cytotoxic test and MTT assay. HK-2 cells were transfected with CaN small interference RNA (siRNA). The mRNA and protein expressions of FN, ColIV, TGF-b1, and CaN in HK-2 cells were detected by real-time PCR and western blot. The CaN/NFAT pathway was examined by indirect immunofluorescence and western blot. Our study revealed that NCTD concentrations over 5 mg/l had overt cytotoxicity on HK-2 cells. Meanwhile, both 2.5 and 5 mg/l NCTD inhibited HK-2 cell proliferation (Po0.05). NCTD inhibited the upregulation of FN, ColIV, and TGF-b1 of HK-2 cells stimulated by high glucose (Po0.05), and also significantly downregulated the expression of CaN mRNA and protein in HK-2 cells (Po0.05). In addition, not only was the nuclear translocation of NFATc inhibited, but its protein level in the nucleus was also reduced. Following CaN siRNA transfection, CaN mRNA and protein expression were significantly decreased. In contrast, the protein levels of FN, ColIV, and TGF-b1 increased in HK-2 cells stimulated by high glucose (Po0.05). However, NCTD treatment downregulated their expression. These results indicated that NCTD could decrease the expression of ECM and TGF-b1 in HK-2 cells stimulated by high glucose, downregulate CaN expression, and block the CaN/NFAT signaling pathway. However, the effect of NCTD on inhibition of the expression of ECM and TGF-b1 was not associated with its inhibition of the CaN/NFAT pathway.

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Calcineurin A-β is required for hypertrophy but not matrix expansion in the diabetic kidney

Cited by 17 publications

References 28 publications

Insulin Increases Expression of TRPC6 Channels in Podocytes by a Calcineurin-Dependent Pathway

Insulin Increases Expression of TRPC6 Channels in Podocytes by a Calcineurin-Dependent Pathway

miR-23a is decreased during muscle atrophy by a mechanism that includes calcineurin signaling and exosome-mediated export

Norcantharidin inhibits the expression of extracellular matrix and TGF-β1 in HK-2 cells induced by high glucose independent of calcineurin signal pathway

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