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Inactivation of TSC1 promotes epithelial-mesenchymal transition of renal tubular epithelial cells in mouse diabetic nephropathy. Acta Pharmacol Sin 2019; 40:1555-1567. [PMID: 31235817 PMCID: PMC7468253 DOI: 10.1038/s41401-019-0244-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Accepted: 04/25/2019] [Indexed: 02/06/2023] Open
Abstract
Epithelial–mesenchymal transition (EMT) of renal tubular epithelial cells is one of the potential mechanisms of renal fibrosis, which promotes the development of diabetic nephropathy (DN). However, the molecular mechanisms of EMT remain largely unknown. Tuberous sclerosis proteins TSC1 and TSC2 are key integrators of growth factor signaling, and the loss of TSC1 or TSC2 function leads to a spectrum of diseases that underlie abnormalities in cell growth, proliferation, differentiation, and migration. In this study, we investigated the effects of TSC1 on high glucose (HG)-induced EMT of human proximal tubular epithelial HK-2 cells in vitro and renal fibrosis in TSC1−/− and db/db mice. We found that the exposure of HK-2 cells to HG (30 mM) time-dependently decreased TSC1 expression, increased the phosphorylation of mTORC1, P70S6K, and 4E-BP-1, and promoted cell migration, resulting in EMT. Transfection of the cells with TSC1 mimic significantly ameliorated HG-induced EMT of HK-2 cells. The tubules-specific TSC1 knockout mice (TSC1−/−) displayed a significant decline in renal function. TSC1−/− mice, similar to db/db mice, showed greatly activated mTORC1 signaling and EMT process in the renal cortex and exacerbated renal fibrosis. Overexpression of TSC1 through LV-TSC1 transfection significantly alleviated the progression of EMT and renal fibrosis in the renal cortex of db/db mice. Taken together, our results suggest that TSC1 plays a key role in mediating HG-induced EMT, and inhibition of TSC1-regulated mTORC1 signaling may be a potential approach to prevent renal fibrosis in DN.
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Abstract
One of the first structural changes in diabetic nephropathy (DN) is the renal enlargement. These changes resulted in renal hypertrophy in both glomerular and tubular cells. Shrink in the kidney size, which described as kidney atrophy resulted from the loss of nephrons or abnormal nephron function and lead to loss of the kidney function. On the other hand, increase in kidney size, which described as hypertrophy resulted from increase in proximal tubular epithelial and glomerular cells size. However overtime, tubular atrophy and tubulointerstitial fibrosis occurs as subsequent changes in tubular cell hypertrophy, which is associated with the infiltration of fibroblast cells into the tubulointerstitial space. The rate of deterioration of kidney function shows a strong correlation with the degree of tubulointerstitial fibrosis. A consequence of long-standing diabetes/hyperglycemia may lead to major changes in renal structure that occur but not specific only to nephropathy. Identifying type of cells that involves in renal atrophy and hypertrophy may help to find a therapeutic target to treat diabetic nephropathy. In summary, the early changes in diabetic kidney are mainly includes the increase in tubular basement membrane thickening which lead to renal hypertrophy. On the other hand, only renal tubule is subjected to apoptosis, which is one of the characteristic morphologic changes in diabetic kidney to form tubular atrophy at the late stage of diabetes.
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Affiliation(s)
- Samy L Habib
- a Department of Geriatric, Geriatric Research, Education, and Clinical Center , South Texas Veterans Healthcare System , San Antonio , TX.,b Department of Cell Systems and Anatomy , University of Texas Health Science Center at San Antonio , San Antonio , TX
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Al-Obaidi N, Mohan S, Liang S, Zhao Z, Nayak BK, Li B, Sriramarao P, Habib SL. Galectin-1 is a new fibrosis protein in type 1 and type 2 diabetes. FASEB J 2018; 33:373-387. [PMID: 29975570 DOI: 10.1096/fj.201800555rr] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Chronic exposure of tubular renal cells to high glucose contributes to tubulointerstitial changes in diabetic nephropathy. In the present study, we identified a new fibrosis gene called galectin-1 (Gal-1), which is highly expressed in tubular cells of kidneys of type 1 and type 2 diabetic mouse models. Gal-1 protein and mRNA expression showed significant increase in kidney cortex of heterozygous Akita+/- and db/db mice compared with wild-type mice. Mouse proximal tubular cells exposed to high glucose showed significant increase in phosphorylation of Akt and Gal-1. We cloned Gal-1 promoter and identified the transcription factor AP4 as binding to the Gal-1 promoter to up-regulate its function. Transfection of cells with plasmid carrying mutations in the binding sites of AP4 to Gal-1 promoter resulted in decreased protein function of Gal-1. In addition, inhibition of Gal-1 by OTX-008 showed significant decrease in p-Akt/AP4 and protein-promoter activity of Gal-1 and fibronectin. Moreover, down-regulation of AP4 by small interfering RNA resulted in a significant decrease in protein expression and promoter activity of Gal-1. We found that kidney of Gal-1-/- mice express very low levels of fibronectin protein. In summary, Gal-1 is highly expressed in kidneys of type 1 and 2 diabetic mice, and AP4 is a major transcription factor that activates Gal-1 under hyperglycemia. Inhibition of Gal-1 by OTX-008 blocks activation of Akt and prevents accumulation of Gal-1, suggesting a novel role of Gal-1 inhibitor as a possible therapeutic target to treat renal fibrosis in diabetes.-Al-Obaidi, N., Mohan, S., Liang, S., Zhao, Z., Nayak, B. K., Li, B., Sriramarao, P., Habib, S. L. Galectin-1 is a new fibrosis protein in type 1 and type 2 diabetes.
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Affiliation(s)
- Noor Al-Obaidi
- Department of Cell Systems and Anatomy, University of Texas Health, San Antonio, Texas, USA
| | - Sumathy Mohan
- Department of Pathology, University of Texas Health, San Antonio, Texas, USA
| | - Sitai Liang
- Department of Cell Systems and Anatomy, University of Texas Health, San Antonio, Texas, USA
| | - Zhenze Zhao
- Department of Cell Systems and Anatomy, University of Texas Health, San Antonio, Texas, USA
| | - Bijaya K Nayak
- Department of Cell Systems and Anatomy, University of Texas Health, San Antonio, Texas, USA
| | - Boajie Li
- Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, China
| | - P Sriramarao
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota, USA; and
| | - Samy L Habib
- Department of Cell Systems and Anatomy, University of Texas Health, San Antonio, Texas, USA.,Geriatric Research Education and Clinical Center, South Texas, Veterans Healthcare System, San Antonio, Texas, USA
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Ercan S, Şahin P, Kencebay C, Derin N, Çelik Özenci Ç. Evaluation of mTOR signaling pathway proteins in rat gastric mucosa exposed to sulfite and ghrelin. TURKISH JOURNAL OF GASTROENTEROLOGY 2017; 29:94-100. [PMID: 29082888 DOI: 10.5152/tjg.2017.17294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND/AIMS Mammalian target of rapamycin (mTOR) signaling serves as a central regulator of cell growth, proliferation, and survival. In this study, we planned to evaluate the expressions of mTOR signaling constituents (p-p70S6K, p-mTOR, and p-Tuberin) in rat gastric mucosa and to compare the results in sulfite- and sulfite+ghrelin-exposed groups. MATERIALS AND METHODS Rats were divided into three groups: the control group (C), the sodium metabisulfite (Na2S2O5) (S) group, and sulfite+ghrelin (SG) group. Sodium metabisulfite at 100 mg/kg/day was administered via gavage, and ghrelin at 20 μg/kg/day was administered intraperitoneally for 35 days. We have used immunohistochemistry for mTOR signaling pathway components. RESULTS There were no significant differences for p-p70S6K and p-mTOR expression among the C, S, and SG groups. Tuberin expression was significantly increased in the S group compared to the C group. Furthermore, tuberin expression was found to be significantly decreased in the SG group. CONCLUSION This study is the first one in the literature that shows the expression of mTOR signaling proteins in gastric mucosa of rats exposed to sulfite and ghrelin. Furthermore, it demonstrates that ghrelin treatment reduces p-Tuberin expression induced by ingested sulfite.
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Affiliation(s)
- Sevim Ercan
- Department of Medical Services and Techniques, Akdeniz University Vocational School of Health Services, Antalya, Turkey
| | - Pınar Şahin
- Department of Histology and Embryology, Akdeniz University School of Medicine, Antalya, Turkey
| | - Ceren Kencebay
- Department of Biophysics, Akdeniz University School of Medicine, Antalya, Turkey
| | - Narin Derin
- Department of Biophysics, Akdeniz University School of Medicine, Antalya, Turkey
| | - Çiler Çelik Özenci
- Department of Histology and Embryology, Akdeniz University School of Medicine, Antalya, Turkey
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Bera A, Das F, Ghosh-Choudhury N, Mariappan MM, Kasinath BS, Ghosh Choudhury G. Reciprocal regulation of miR-214 and PTEN by high glucose regulates renal glomerular mesangial and proximal tubular epithelial cell hypertrophy and matrix expansion. Am J Physiol Cell Physiol 2017; 313:C430-C447. [PMID: 28701356 PMCID: PMC5668576 DOI: 10.1152/ajpcell.00081.2017] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 07/06/2017] [Accepted: 07/09/2017] [Indexed: 02/06/2023]
Abstract
Aberrant expression of microRNAs (miRs) contributes to diabetic renal complications, including renal hypertrophy and matrix protein accumulation. Reduced expression of phosphatase and tensin homolog (PTEN) by hyperglycemia contributes to these processes. We considered involvement of miR in the downregulation of PTEN. In the renal cortex of type 1 diabetic mice, we detected increased expression of miR-214 in association with decreased levels of PTEN and enhanced Akt phosphorylation and fibronectin expression. Mesangial and proximal tubular epithelial cells exposed to high glucose showed augmented expression of miR-214. Mutagenesis studies using 3'-UTR of PTEN in a reporter construct revealed PTEN as a direct target of miR-214, which controls its expression in both of these cells. Overexpression of miR-214 decreased the levels of PTEN and increased Akt activity similar to high glucose and lead to phosphorylation of its substrates glycogen synthase kinase-3β, PRAS40, and tuberin. In contrast, quenching of miR-214 inhibited high-glucose-induced Akt activation and its substrate phosphorylation; these changes were reversed by small interfering RNAs against PTEN. Importantly, respective expression of miR-214 or anti-miR-214 increased or decreased the mammalian target of rapamycin complex 1 (mTORC1) activity induced by high glucose. Furthermore, mTORC1 activity was controlled by miR-214-targeted PTEN via Akt activation. In addition, neutralization of high-glucose-stimulated miR-214 expression significantly inhibited cell hypertrophy and expression of the matrix protein fibronectin. Finally, the anti-miR-214-induced inhibition of these processes was reversed by the expression of constitutively active Akt kinase and hyperactive mTORC1. These results uncover a significant role of miR-214 in the activation of mTORC1 that contributes to high-glucose-induced mesangial and proximal tubular cell hypertrophy and fibronectin expression.
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Affiliation(s)
- Amit Bera
- Department of Medicine, UT Health San Antonio, San Antonio, Texas
| | - Falguni Das
- Department of Medicine, UT Health San Antonio, San Antonio, Texas
| | - Nandini Ghosh-Choudhury
- Veterans Affairs Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, Texas
- Department of Pathology, UT Health San Antonio, San Antonio, Texas; and
| | | | - Balakuntalam S Kasinath
- Department of Medicine, UT Health San Antonio, San Antonio, Texas
- Veterans Affairs Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, Texas
| | - Goutam Ghosh Choudhury
- Department of Medicine, UT Health San Antonio, San Antonio, Texas;
- Veterans Affairs Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, Texas
- Geriatric Research, Education and Clinical Research, South Texas Veterans Health Care System, San Antonio, Texas
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Mohammadipanah F, Salimi F. Potential biological targets for bioassay development in drug discovery of Sturge-Weber syndrome. Chem Biol Drug Des 2017; 91:359-369. [PMID: 28941044 DOI: 10.1111/cbdd.13112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 06/10/2017] [Accepted: 09/18/2017] [Indexed: 01/02/2023]
Abstract
Sturge-Weber Syndrome (SWS) is a neurocutaneous disease with clinical manifestations including ocular (glaucoma), cutaneous (port-wine birthmark), neurologic (seizures), and vascular problems. Molecular mechanisms of SWS pathogenesis are initiated by the somatic mutation in GNAQ. Therefore, no definite treatments exist for SWS and treatment options only mitigate the intensity of its clinical manifestations. Biological assay design for drug discovery against this syndrome demands comprehensive knowledge on mechanisms which are involved in its pathogenesis. By analysis of the interrelated molecular targets of SWS, some in vitro bioassay systems can be allotted for drug screening against its progression. Development of such platforms of bioassay can bring along the implementation of high-throughput screening of natural or synthetic compounds in drug discovery programs. Regarding the fact that study of molecular targets and their integration in biological assay design can facilitate the process of effective drug discovery; some potential biological targets and their respective biological assay for SWS drug discovery are propounded in this review. For this purpose, some biological targets for SWS drug discovery such as acetylcholinesterase, alkaline phosphatase, GABAergic receptors, Hypoxia-Inducible Factor (HIF)-1α and 2α are suggested.
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Affiliation(s)
- Fatemeh Mohammadipanah
- Department of Microbial Biotechnology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran
| | - Fatemeh Salimi
- Department of Microbial Biotechnology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran
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Habib SL, Yadav A, Kidane D, Weiss RH, Liang S. Novel protective mechanism of reducing renal cell damage in diabetes: Activation AMPK by AICAR increased NRF2/OGG1 proteins and reduced oxidative DNA damage. Cell Cycle 2016; 15:3048-3059. [PMID: 27611085 DOI: 10.1080/15384101.2016.1231259] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Exposure of renal cells to high glucose (HG) during diabetes has been recently proposed to be involved in renal injury. In the present study, we investigated a potential mechanism by which AICAR treatment regulates the DNA repair enzyme, 8-oxoG-DNA glycosylase (OGG1) in renal proximal tubular mouse cells exposed to HG and in kidney of db/db mice. Cells treated with HG for 2 days show inhibition in OGG1 promoter activity as well as OGG1 and Nrf2 protein expression. In addition, activation of AMPK by AICAR resulted in an increase raptor phosphorylation at Ser792 and leads to increase the promoter activity of OGG1 through upregulation of Nrf2. Downregulation of AMPK by DN-AMPK and raptor and Nrf2 by siRNA resulted in significant decease in promoter activity and protein expression of OGG1. On the other hand, downregulation of Akt by DN-Akt and rictor by siRNA resulted in significant increase in promoter activity and protein expression of Nrf2 and OGG1. Moreover, gel shift analysis shows reduction of Nrf2 binding to OGG1 promoter in cells treated with HG while cells treated with AICAR reversed the effect of HG. Furthermore, db/db mice treated with AICAR show significant increased in AMPK and raptor phosphroylation as well as OGG1 and Nrf2 protein expression that associated with significant decrease in oxidative DNA damage (8-oxodG) compared to non-treated mice. In summary, our data provide a novel protective mechanism by which AICAR prevents renal cell damage in diabetes and the consequence complications of hyperglycemia with a specific focus on nephropathy.
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Affiliation(s)
- Samy L Habib
- a Department of Cellular and Structural Biology , University of Texas Health Science Center , San Antonio , TX , USA.,b Geriatric Research, Education and Clinical Department , South Texas Veterans Health Care System , San Antonio , TX , USA
| | - Anamika Yadav
- a Department of Cellular and Structural Biology , University of Texas Health Science Center , San Antonio , TX , USA
| | - Dawit Kidane
- c Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute , Austin , TX , USA
| | - Robert H Weiss
- d Division of Nephrology and Cancer Center, University of California at Davis , Davis , CA , USA
| | - Sitai Liang
- a Department of Cellular and Structural Biology , University of Texas Health Science Center , San Antonio , TX , USA
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Aizawa Y, Shirai T, Kobayashi T, Hino O, Tsujii Y, Inoue H, Kazami M, Tadokoro T, Suzuki T, Kobayashi KI, Yamamoto Y. Metabolic abnormalities induced by mitochondrial dysfunction in skeletal muscle of the renal carcinoma Eker (TSC2+/-) rat model. Biosci Biotechnol Biochem 2016; 80:1513-9. [PMID: 27031579 DOI: 10.1080/09168451.2016.1165603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Tuberous sclerosis complex 2 (TSC2) is a mediator of insulin signal transduction, and a loss of function in TSC2 induces hyperactivation of mTORC1 pathway, which leads to tumorigenesis. We have previously demonstrated that Eker rat model, which is heterozygous for a TSC2 mutation, exhibits hyperglycemia and hyperketonemia. The present study was to investigate whether these changes also can affect metabolism in skeletal muscle of the Eker rat. Wild-type (TSC2+/+) and Eker (TSC2+/-) rats underwent an oral glucose tolerance test, and the latter showed decrease in whole-body glucose utilization. Additionally, reductions in the expression of glycolysis-, lipolysis-, and ketone body-related genes in skeletal muscle were observed in Eker rats. Furthermore, ATP content and mitochondrial DNA copy number were lower in skeletal muscle of Eker rats. These data demonstrate that heterozygous to mutation TSC2 not only affects the liver metabolism, but also skeletal muscle metabolism, via mitochondrial dysfunction.
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Affiliation(s)
- Yumi Aizawa
- a Faculty of Applied Bioscience , Tokyo University of Agriculture , Tokyo , Japan
| | - Tomomi Shirai
- a Faculty of Applied Bioscience , Tokyo University of Agriculture , Tokyo , Japan
| | - Toshiyuki Kobayashi
- b Faculty of Medicine, Department of Pathology and Oncology , Juntendo University , Tokyo , Japan
| | - Okio Hino
- b Faculty of Medicine, Department of Pathology and Oncology , Juntendo University , Tokyo , Japan
| | - Yoshimasa Tsujii
- a Faculty of Applied Bioscience , Tokyo University of Agriculture , Tokyo , Japan
| | - Hirofumi Inoue
- a Faculty of Applied Bioscience , Tokyo University of Agriculture , Tokyo , Japan
| | - Machiko Kazami
- a Faculty of Applied Bioscience , Tokyo University of Agriculture , Tokyo , Japan
| | - Tadahiro Tadokoro
- a Faculty of Applied Bioscience , Tokyo University of Agriculture , Tokyo , Japan
| | - Tsukasa Suzuki
- a Faculty of Applied Bioscience , Tokyo University of Agriculture , Tokyo , Japan
| | - Ken-Ichi Kobayashi
- a Faculty of Applied Bioscience , Tokyo University of Agriculture , Tokyo , Japan
| | - Yuji Yamamoto
- a Faculty of Applied Bioscience , Tokyo University of Agriculture , Tokyo , Japan
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Lin M, Gao P, Zhao T, He L, Li M, Li Y, Shui H, Wu X. Calcitriol regulates angiotensin-converting enzyme and angiotensin converting-enzyme 2 in diabetic kidney disease. Mol Biol Rep 2016; 43:397-406. [PMID: 26968558 DOI: 10.1007/s11033-016-3971-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 03/05/2016] [Indexed: 10/22/2022]
Abstract
To investigate the effects of calcitriol on angiotensin-converting enzyme (ACE) and ACE2 in diabetic nephropathy. Streptozotocin (STZ) induced diabetic rats were treated with calcitriol for 16 weeks. ACE/ACE2 and mitogen activated protein kinase (MAPK) enzymes were measured in the kidneys of diabetic rats and rat renal tubular epithelial cells exposed to high glucose. Calcitriol reduced proteinuria in diabetic rats without affecting calcium-phosphorus metabolism. ACE and ACE2 levels were significantly elevated in diabetic rats compared to those in control rats. The increase in ACE levels was greater than that of ACE2, leading to an elevated ACE/ACE2 ratio. Calcitriol reduced ACE levels and ACE/ACE2 ratio and increased ACE2 levels in diabetic rats. Similarly, high glucose up-regulated ACE expression in NRK-52E cells, which was blocked by the p38 MAPK inhibitor SB203580, but not the extracellular signal-regulated kinase (ERK) inhibitor FR180204 or the c-Jun N-terminal kinase (JNK) inhibitor SP600125. High glucose down-regulated ACE2 expression, which was blocked by FR180204, but not SB203580 or SP600125. Incubation of cells with calcitriol significantly inhibited p38 MAPK and ERK phosphorylation, but not JNK phosphorylation, and effectively attenuated ACE up-regulation and ACE2 down-regulation in high glucose conditions. The renoprotective effects of calcitriol in diabetic nephropathy were related to the regulation of tubular levels of ACE and ACE2, possibly by p38 MAPK or ERK, but not JNK pathways.
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Affiliation(s)
- Mei Lin
- Department of Nephrology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei, China
| | - Ping Gao
- Department of Nephrology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei, China.
| | - Tianya Zhao
- Department of Nephrology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei, China
| | - Lei He
- Department of Nephrology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei, China
| | - Mengshi Li
- Department of Nephrology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei, China
| | - Yaoyao Li
- Department of Nephrology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei, China
| | - Hua Shui
- Department of Nephrology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei, China
| | - Xiaoyan Wu
- Department of Nephrology, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei, China
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Habib SL, Mohan S, Liang S, Li B, Yadav M. Novel mechanism of transcriptional regulation of cell matrix protein through CREB. Cell Cycle 2015; 14:2598-608. [PMID: 26115221 DOI: 10.1080/15384101.2015.1064204] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The transcription mechanism(s) of renal cell matrix accumulation in diabetes does not explored. Phosphorylation of the transcription factor cAMP-responsive element binding protein (CREB) significantly increased in cells treated with high glucose (HG) compared to cell grown in normal glucose (NG). Cells pretreated with rapamycin before exposure to HG showed significant decrease phosphorylation of CREB, increase in AMPK activity and decrease protein/mRNA and promoter activity of fibronectin. In addition, cells transfected with siRNA against CREB showed significant increase in AMPK activity, decrease in protein/mRNA and promoter activity of fibronectin. Cells treated with HG showed nuclear localization of p-CREB while pretreated cells with rapamycin reversed HG effect. Moreover, gel shift analysis shows increase binding of CREB to fibronectin promoter in cells treated with HG while cells pretreated with rapamycin reversed the effect of HG. Furthermore, db/db mice treated with rapamycin showed significant increase in AMPK activity, decrease in expression of p-CREB and protein/mRNA of fibronectin. Strong staining of fibronectin and p-CREB was detected in kidney cortex of db/db mice while treated mice with rapamycin reversed hyperglycemia effect. In summary, our data provide a novel mechanism of transcriptional regulation of fibronectin through CREB that may be used as therapeutic approach to prevent diabetes complications.
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Affiliation(s)
- Samy L Habib
- a South Texas Veterans Health Care System ; San Antonio , TX USA
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11
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Thakur S, Viswanadhapalli S, Kopp JB, Shi Q, Barnes JL, Block K, Gorin Y, Abboud HE. Activation of AMP-activated protein kinase prevents TGF-β1-induced epithelial-mesenchymal transition and myofibroblast activation. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:2168-80. [PMID: 26071397 DOI: 10.1016/j.ajpath.2015.04.014] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 03/27/2015] [Accepted: 04/21/2015] [Indexed: 12/26/2022]
Abstract
Transforming growth factor (TGF)-β contributes to tubulointerstitial fibrosis. We investigated the mechanism by which TGF-β exerts its profibrotic effects and specifically the role of AMP-activated protein kinase (AMPK) in kidney tubular epithelial cells and interstitial fibroblasts. In proximal tubular epithelial cells, TGF-β1 treatment causes a decrease in AMPK phosphorylation and activation together with increased fibronectin and α-smooth muscle actin expression and decreased in E-cadherin. TGF-β1 causes similar changes in interstitial fibroblasts. Activation of AMPK with 5-aminoimidazole-4-carboxamide 1-β-d-ribofuranoside, metformin, or overexpression of constitutively active AMPK markedly attenuated TGF-β1 functions. Conversely, inhibition of AMPK with adenine 9-β-d-arabinofuranoside or siRNA-mediated knockdown of AMPK (official name PRKAA1) mimicked the effect of TGF-β1 and enhanced basal and TGF-β1-induced phenotypic changes. Importantly, we found that tuberin contributed to the protective effects of AMPK and that TGF-β1 promoted cell injury by blocking AMPK-mediated tuberin phosphorylation and activation. In the kidney cortex of TGF-β transgenic mice, the significant decrease in AMPK phosphorylation and tuberin phosphorylation on its AMPK-dependent activating site was associated with an increase in mesenchymal markers and a decrease in E-cadherin. Collectively, the data indicate that TGF-β exerts its profibrotic action in vitro and in vivo via inactivation of AMPK. AMPK and tuberin activation prevent tubulointerstitial injury induced by TGF-β. Activators of AMPK provide potential therapeutic strategy to prevent kidney fibrosis and progressive kidney disease.
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Affiliation(s)
- Sachin Thakur
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | | | - Jeffrey B Kopp
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Qian Shi
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Jeffrey L Barnes
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Karen Block
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas; Audie L. Murphy Memorial Hospital Division, South Texas Veterans Healthcare System, San Antonio, Texas
| | - Yves Gorin
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Hanna E Abboud
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas; Audie L. Murphy Memorial Hospital Division, South Texas Veterans Healthcare System, San Antonio, Texas
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Hyperactivation of Akt/mTOR and deficiency in tuberin increased the oxidative DNA damage in kidney cancer patients with diabetes. Oncotarget 2015; 5:2542-50. [PMID: 24797175 PMCID: PMC4058025 DOI: 10.18632/oncotarget.1833] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Recent study from our laboratory showed that patients with diabetes are at a higher risk of developing kidney cancer. In the current study, we have explored one of the mechanisms by which diabetes accelerates tumorigenesis in the kidney. Kidney cancer tissue from patients with diabetes showed a higher activity of Akt and decreased in total protein of tuberin compared to kidney cancer patient without diabetes or diabetes alone. In addition, a significant increase in phospho-Akt/tuberin expression was associated with an increase in Ki67 expression and activation of mTOR in kidney tumor with or without diabetes compared to diabetes alone. In addition, decrease in tuberin expression resulted in a significant decrease in protein expression of OGG1 and increased in oxidative DNA damage, 8-oxodG in kidney tissues from patients with cancer or cancer+diabetes. Importantly, these data showed that the majority of the staining of Akt/tuberin/p70S6K phosphorylation was more prominently in the tubular cells. In addition, accumulation of oxidative DNA damage is localized only in the nucleus of tubular cells within the cortex region. These data suggest that Akt/tuberin/mTOR pathway plays an important role in the regulation DNA damage and repair pathways that may predispose diabetic kidneys to pathogenesis of renal cell carcinoma.
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13
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Affiliation(s)
- Samy L Habib
- Department of Geriatrics; Geriatric Research, Education, and Clinical Center; South Texas Veterans Healthcare System; San Antonio, TX USA; Department of Cellular and Structural Biology; University of Texas Health Science Center at San Antonio; San Antonio, TX USA
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14
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Wu H, Kong L, Zhou S, Cui W, Xu F, Luo M, Li X, Tan Y, Miao L. The role of microRNAs in diabetic nephropathy. J Diabetes Res 2014; 2014:920134. [PMID: 25258717 PMCID: PMC4165734 DOI: 10.1155/2014/920134] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 07/29/2014] [Indexed: 01/27/2023] Open
Abstract
Diabetic nephropathy (DN), as one of the chronic complications of diabetes, is the major cause of end-stage renal disease. However, the pathogenesis of this disease is not fully understood. In recent years, research on microRNAs (miRNAs) has become a hotspot because of their critical role in regulating posttranscriptional levels of protein-coding genes that may serve as key pathogenic factors in diseases. Several miRNAs were found to participate in the pathogenesis of DN, while others showed renal protective effects. Therefore, targeting miRNAs that are involved in DN may have a good prospect in the treatment of the disease. The aim of this review is to summarize DN-related miRNAs and provide potential targets for diagnostic strategies and therapeutic intervention.
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Affiliation(s)
- Hao Wu
- Department of Nephrology, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China
- Chinese-American Research Institute for Diabetic Complications at Wenzhou Medical University, Wenzhou 325035, China
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville, KY 40202, USA
| | - Lili Kong
- Department of Nephrology, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville, KY 40202, USA
| | - Shanshan Zhou
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville, KY 40202, USA
- Cardiovascular Center, The First Hospital of Jilin University, Changchun 130021, China
| | - Wenpeng Cui
- Department of Nephrology, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China
| | - Feng Xu
- Department of Nephrology, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China
| | - Manyu Luo
- Department of Nephrology, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville, KY 40202, USA
| | - Xiangqi Li
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Shanghai 200031, China
| | - Yi Tan
- Chinese-American Research Institute for Diabetic Complications at Wenzhou Medical University, Wenzhou 325035, China
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville, KY 40202, USA
- *Yi Tan: and
| | - Lining Miao
- Department of Nephrology, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China
- *Lining Miao:
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Novel mechanism of regulation of fibrosis in kidney tumor with tuberous sclerosis. Mol Cancer 2013; 12:49. [PMID: 23705901 PMCID: PMC3681649 DOI: 10.1186/1476-4598-12-49] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 05/22/2013] [Indexed: 01/19/2023] Open
Abstract
Background Deficiency in tuberin results in activation the mTOR pathway and leads to accumulation of cell matrix proteins. The mechanisms by which tuberin regulates fibrosis in kidney angiomyolipomas (AMLs) of tuberous sclerosis patients are not fully known. Method In the present study, we investigated the potential role of tuberin/mTOR pathway in the regulation of cell fibrosis in AML cells and kidney tumor tissue from tuberous sclerosis complex (TSC) patients. Results AML cells treated with rapamycin shows a significant decrease in mRNA and protein expression as well as in promoter transcriptional activity of alpha-smooth muscle actin (α-SMA) compared to untreated cells. In addition, cells treated with rapamycin significantly decreased the protein expression of the transcription factor YY1. Rapamycin treatment also results in the redistribution of YY1 from the nucleus to cytoplasm in AML cells. Moreover, cells treated with rapamycin resulted in a significant reduce of binding of YY1 to the αSMA promoter element in nuclear extracts of AML cells. Kidney angiomyolipoma tissues from TSC patients showed lower levels of tuberin and higher levels of phospho-p70S6K that resulted in higher levels of mRNA and protein of αSMA expression compared to control kidney tissues. In addition, most of the α-SMA staining was identified in the smooth muscle cells of AML tissues. YY1 was also significantly increased in tumor tissue of AMLs compared to control kidney tissue suggesting that YY1 plays a major role in the regulation of αSMA. Conclusions These data comprise the first report to provide one mechanism whereby rapamycin might inhibit the cell fibrosis in kidney tumor of TSC patients.
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16
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Jiang L, Xu L, Mao J, Li J, Fang L, Zhou Y, Liu W, He W, Zhao AZ, Yang J, Dai C. Rheb/mTORC1 signaling promotes kidney fibroblast activation and fibrosis. J Am Soc Nephrol 2013; 24:1114-26. [PMID: 23661807 DOI: 10.1681/asn.2012050476] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Ras homolog enriched in brain (Rheb) is a small GTPase that regulates cell growth, differentiation, and survival by upregulating mammalian target of rapamycin complex 1 (mTORC1) signaling. The role of Rheb/mTORC1 signaling in the activation of kidney fibroblasts and the development of kidney fibrosis remains largely unknown. In this study, we found that Rheb/mTORC1 signaling was activated in interstitial myofibroblasts from fibrotic kidneys. Treatment of rat kidney interstitial fibroblasts (NRK-49F cell line) with TGFβ1 also activated Rheb/mTORC1 signaling. Blocking Rheb/mTORC1 signaling with rapamycin or Rheb small interfering RNA abolished TGFβ1-induced fibroblast activation. In a transgenic mouse, ectopic expression of Rheb activated kidney fibroblasts. These Rheb transgenic mice exhibited increased activation of mTORC1 signaling in both kidney tubular and interstitial cells as well as progressive interstitial renal fibrosis; rapamycin inhibited these effects. Similarly, mice with fibroblast-specific deletion of Tsc1, a negative regulator of Rheb, exhibited activated mTORC1 signaling in kidney interstitial fibroblasts and increased renal fibrosis, both of which rapamycin abolished. Taken together, these results suggest that Rheb/mTORC1 signaling promotes the activation of kidney fibroblasts and contributes to the development of interstitial fibrosis, possibly providing a therapeutic target for progressive renal disease.
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Affiliation(s)
- Lei Jiang
- Center for Kidney Disease, Second Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
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