scholarly journals Transforming Growth Factor Beta 1 Drives a Switch in Connexin Mediated Cell-to-Cell Communication in Tubular Cells of the Diabetic Kidney

2018 ◽  
Vol 45 (6) ◽  
pp. 2369-2388 ◽  
Author(s):  
Claire Hills ◽  
Gareth William Price ◽  
Mark John Wall ◽  
Timothy John Kaufmann ◽  
Chi-Wai Tang ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Epithelial Cells ◽  
Transforming Growth Factor ◽  
Cell Communication ◽  
Atp Release ◽  
Immunoblot Analysis ◽  
Biopsy Material ◽  
Junctional Conductance ◽  
Fibronectin Expression ◽  
Tgf Β1

Background/Aims: Changes in cell-to-cell communication have been linked to several secondary complications of diabetes, but the mechanism by which connexins affect disease progression in the kidney is poorly understood. This study examines a role for glucose-evoked changes in the beta1 isoform of transforming growth factor (TGFβ1), on connexin expression, gap-junction mediated intercellular communication (GJIC) and hemi-channel ATP release from tubular epithelial cells of the proximal renal nephron. Methods: Biopsy material from patients with and without diabetic nephropathy was stained for connexin-26 (CX26) and connexin-43 (CX43). Changes in expression were corroborated by immunoblot analysis in human primary proximal tubule epithelial cells (hPTECs) and model epithelial cells from human renal proximal tubules (HK2) cultured in either low glucose (5mmol/L) ± TGFβ1 (2-10ng/ml) or high glucose (25mmol/L) for 48h or 7days. Secretion of the cytokine was determined by ELISA. Paired whole cell patch clamp recordings were used to measure junctional conductance in control versus TGFβ1 treated (10ng/ml) HK2 cells, with carboxyfluorescein uptake and ATP-biosensing assessing hemi-channel function. A downstream role for ATP in mediating the effects of TGF-β1 on connexin mediated cell communication was assessed by incubating cells with ATPγS (1-100µM) or TGF-β1 +/- apyrase (5 Units/ml). Implications of ATP release were measured through immunoblot analysis of interleukin 6 (IL-6) and fibronectin expression. Results: Biopsy material from patients with diabetic nephropathy exhibited increased tubular expression of CX26 and CX43 (P<0.01, n=10), data corroborated in HK2 and hPTEC cells cultured in TGFβ1 (10ng/ml) for 7days (P<0.001, n=3). High glucose significantly increased TGFβ1 secretion from tubular epithelial cells (P<0.001, n=3). The cytokine (10ng/ml) reduced junctional conductance between HK2 cells from 4.5±1.3nS in control to 1.15±0.9nS following 48h TGFβ1 and to 0.42±0.2nS after 7days TGFβ1 incubation (P<0.05, n=5). Acute (48h) and chronic (7day) challenge with TGFβ1 produced a carbenoxolone (200µM)-sensitive increase in carboxyfluorescein loading, matched by an increase in ATP release from 0.29±0.06μM in control to 1.99±0.47μM after 48hr incubation with TGFβ1 (10ng/ml; P<0.05, n=3). TGF-β1 (2-10ng/ml) and ATPγs (1-100µM) increased expression of IL-6 (P<0.001 n=3) and fibronectin (P<0.01 n=3). The effect of TGF-β1 on IL-6 and fibronectin expression was partially blunted when preincubated with apyrase (n=3). Conclusion: These data suggest that chronic exposure to glucose-evoked TGFβ1 induce an increase in CX26 and CX43 expression, consistent with changes observed in tubular epithelia from patients with diabetic nephropathy. Despite increased connexin expression, direct GJIC communication decreases, whilst hemichannel expression/function and paracrine release of ATP increases, changes that trigger increased levels of expression of interleukin 6 and fibronectin. Linked to inflammation and fibrosis, local increases in purinergic signals may exacerbate disease progression and highlight connexin mediated cell communication as a future therapeutic target for diabetic nephropathy.

scholarly journals Identification of a microRNA signature in renal fibrosis: role of miR-21

2011 ◽  
Vol 301 (4) ◽  
pp. F793-F801 ◽  
Author(s):  
Abolfazl Zarjou ◽  
Shanzhong Yang ◽  
Edward Abraham ◽  
Anupam Agarwal ◽  
Gang Liu
Keyword(s):  
Epithelial Cells ◽  
Renal Fibrosis ◽  
Transforming Growth Factor ◽  
Response To Treatment ◽  
Tubular Epithelial Cells ◽  
Altered Expression ◽  
Tnf Α ◽  
Tgf Β1

Renal fibrosis is a final stage of many forms of kidney disease and leads to impairment of kidney function. The molecular pathogenesis of renal fibrosis is currently not well-understood. microRNAs (miRNAs) are important players in initiation and progression of many pathologic processes including diabetes, cancer, and cardiovascular disease. However, the role of miRNAs in kidney injury and repair is not well-characterized. In the present study, we found a unique miRNA signature associated with unilateral ureteral obstruction (UUO)-induced renal fibrosis. We found altered expression in UUO kidneys of miRNAs that have been shown to be responsive to stimulation by transforming growth factor (TGF)-β1 or TNF-α. Among these miRNAs, miR-21 demonstrated the greatest increase in UUO kidneys. The enhanced expression of miR-21 was located mainly in distal tubular epithelial cells. miR-21 expression was upregulated in response to treatment with TGF-β1 or TNF-α in human renal tubular epithelial cells in vitro. Furthermore, we found that blocking miR-21 in vivo attenuated UUO-induced renal fibrosis, presumably through diminishing the expression of profibrotic proteins and reducing infiltration of inflammatory macrophages in UUO kidneys. Our data suggest that targeting specific miRNAs could be a novel therapeutic approach to treat renal fibrosis.

scholarly journals Autocrine Transforming Growth Factor-β1 Activation Mediated by Integrin αVβ3 Regulates Transcriptional Expression of Laminin-332 in Madin-Darby Canine Kidney Epithelial Cells

2010 ◽  
Vol 21 (21) ◽  
pp. 3654-3668 ◽  
Author(s):  
Jose V. Moyano ◽  
Patricia G. Greciano ◽  
Mary M. Buschmann ◽  
Manuel Koch ◽  
Karl S. Matlin
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Transforming Growth Factor ◽  
Integrin Αvβ3 ◽  
Type I ◽  
Madin Darby Canine Kidney ◽  
Epithelial Regeneration ◽  
Tgf Β1 ◽  
Darby Canine Kidney ◽  
Canine Kidney

Laminin (LM)-332 is an extracellular matrix protein that plays a structural role in normal tissues and is also important in facilitating recovery of epithelia from injury. We have shown that expression of LM-332 is up-regulated during renal epithelial regeneration after ischemic injury, but the molecular signals that control expression are unknown. Here, we demonstrate that in Madin-Darby canine kidney (MDCK) epithelial cells LM-332 expression occurs only in subconfluent cultures and is turned-off after a polarized epithelium has formed. Addition of active transforming growth factor (TGF)-β1 to confluent MDCK monolayers is sufficient to induce transcription of the LM α3 gene and LM-332 protein expression via the TGF-β type I receptor (TβR-I) and the Smad2–Smad4 complex. Significantly, we show that expression of LM-332 in MDCK cells is an autocrine response to endogenous TGF-β1 secretion and activation mediated by integrin αVβ3 because neutralizing antibodies block LM-332 production in subconfluent cells. In confluent cells, latent TGF-β1 is secreted apically, whereas TβR-I and integrin αVβ3 are localized basolaterally. Disruption of the epithelial barrier by mechanical injury activates TGF-β1, leading to LM-332 expression. Together, our data suggest a novel mechanism for triggering the production of LM-332 after epithelial injury.

scholarly journals FOXO3a is stabilized by USP18-mediated de-ISGylation and inhibits TGF-β1-induced fibronectin expression

2019 ◽  
Vol 68 (3) ◽  
pp. 786-791 ◽  
Author(s):  
Ban Wang ◽  
Yanhui Li ◽  
Heather Wang ◽  
Jing Zhao ◽  
Yutong Zhao ◽  
...  
Keyword(s):  
Half Life ◽  
Transforming Growth Factor ◽  
Fibroblast Cells ◽  
Post Translational Modification ◽  
Human Lung Fibroblast ◽  
Post Translational Modifications ◽  
Cellular Processes ◽  
Fibronectin Expression ◽  
Tgf Β1

FOXO3a belongs to a family of transcription factors characterized by a conserved forkhead box DNA-binding domain. It has been known to regulate various cellular processes including cell proliferation, apoptosis and differentiation. Post-translational modifications of FOXO3a and their roles in the regulation of FOXO3a activity have been well-documented. FOXO3a can be phosphorylated, acetylated and ubiquitinated, however, the ISGylation of FOXO3a has not been reported. Protein overexpression, ISGylation and half-life were measured to determine the post-translational modification of FOXO3a. Human fibroblast cells were treated with transforming growth factor (TGF)-β1 to determine the role of FOXO3a ISGylation in TGF-β1 signaling. FOXO3a’s half-life is around 3.7 hours. Inhibition of the proteasome, not lysosome, extends its half-life. ISGylation, but not ubiquitination of FOXO3a, is increased in the presence of the proteasome inhibitor. Overexpression of ISG15 increases FOXO3a degradation, while overexpression of USP18 stabilizes FOXO3a through de-ISGylation. These results suggest that FOXO3a is degraded in the ISGylation and proteasome system, which can be reversed by USP18, an ISG15-specific deubiquitinase. This study reveals a new molecular mechanism by which ISGylation regulates FOXO3a degradation. Furthermore, we show that the overexpression of FOXO3a attenuated TGF-β1-induced fibronectin expression in human lung fibroblast cells without altering Smad2/3 expression and activation. FOXO3a can be ISGylated, which can regulate FOXO3a stability. USP18/FOXO3a pathway is a potential target for treating TGF-β1-mediated fibrotic diseases such as idiopathic pulmonary fibrosis.

scholarly journals All-Trans Retinoic Acid Attenuates Fibrotic Processes by Downregulating TGF-β1/Smad3 in Early Diabetic Nephropathy

Biomolecules ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 525 ◽  
Author(s):  
Edith Sierra-Mondragon ◽  
Rafael Rodríguez-Muñoz ◽  
Carmen Namorado-Tonix ◽  
Eduardo Molina-Jijon ◽  
Daniel Romero-Trejo ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Retinoic Acid ◽  
Transforming Growth Factor ◽  
Nuclear Translocation ◽  
Smooth Muscle Actin ◽  
Kidney Injury ◽  
Alpha Smooth Muscle Actin ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Tgf Β1

Diabetic nephropathy (DN) involves damage associated to hyperglycemia and oxidative stress. Renal fibrosis is a major pathologic feature of DN. The aim of this study was to evaluate anti-fibrogenic and renoprotective effects of all-trans retinoic acid (ATRA) in isolated glomeruli and proximal tubules of diabetic rats. Diabetes was induced by single injection of streptozotocin (STZ, 60 mg/Kg). ATRA (1 mg/Kg) was administered daily by gavage, from days 3–21 after STZ injection. ATRA attenuated kidney injury through the reduction of proteinuria, renal hypertrophy, increase in natriuresis, as well as early markers of damage such as β2-microglobulin, kidney injury molecule-1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL). The following parameters increased: macrophage infiltration, localization of alpha-smooth muscle actin (αSMA)-positive cells in renal tissue, and pro-fibrotic proteins such as transforming growth factor-β (TGF-β1), laminin beta 1 (LAM-β1), and collagens IV and I. Remarkably, ATRA treatment ameliorated these alterations and attenuated expression and nuclear translocation of Smad3, with increment of glomerular and tubular Smad7. The diabetic condition decreased expression of retinoic acid receptor alpha (RAR-α) through phosphorylation in serine residues mediated by the activation of c-Jun N-terminal kinase (JNK). ATRA administration restored the expression of RAR-α and inhibited direct interactions of JNK/RAR-α. ATRA prevented fibrogenesis through down-regulation of TGF-β1/Smad3 signaling.

MKL1 mediates TGF-β1-induced α-smooth muscle actin expression in human renal epithelial cells

2008 ◽  
Vol 294 (5) ◽  
pp. F1116-F1128 ◽  
Author(s):  
Gerard Elberg ◽  
Lijuan Chen ◽  
Dorit Elberg ◽  
Michael D. Chan ◽  
Charlotte J. Logan ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Epithelial Cells ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Primary Cultures ◽  
Muscle Actin ◽  
Mesenchymal Transition ◽  
Endogenous Expression ◽  
Tgf Β1 ◽  
Stimulation Of

Transforming growth factor-β1 (TGF-β1) is known to induce epithelial-mesenchymal transition in the kidney, a process involved in tubulointerstitial fibrosis. We hypothesized that a coactivator of the serum response factor (SRF), megakaryoblastic leukemia factor-1 (MKL1), stimulates α-smooth muscle actin (α-SMA) transcription in primary cultures of renal tubular epithelial cells (RTC), which convert into myofibroblasts on treatment with TGF-β1. Herein, we study the effect of MKL1 expression on α-SMA in these cells. We demonstrate that TGF-β1 stimulation of α-SMA transcription is mediated through CC(A/T)6-rich GG elements known to bind to SRF. These elements also mediate the MKL1 effect that dramatically activates α-SMA transcription in serum-free media. MKL1 fused to green fluorescent protein localizes to the nucleus and induces α-SMA expression regardless of treatment with TGF-β1. Using proteasome inhibitors, we also demonstrate that the proteolytic ubiquitin pathway regulates MKL1 expression. These data indicate that MKL1 overexpression is sufficient to induce α-SMA expression. Inhibition of endogenous expression of MKL1 by small interfering RNA abolishes TGF-β1 stimulation of α-SMA expression. Therefore, MKL1 is also absolutely required for TGF-β1 stimulation of α-SMA expression. Western blot and immunofluorescence analysis show that overexpressed and endogenous MKL1 are located in the nucleus in non-stimulated RTC. Chromatin immunoprecipitation assay demonstrates that TGF-β1 induces binding of endogenous SRF and MKL1 to the α-SMA promoter in chromatin. Since MKL1 constitutes a potent factor regulating α-SMA expression, modulation of endogenous MKL1 expression or activity may have a profound effect on myofibroblast formation and function in the kidney.

Release of biologically active TGF-β1 by alveolar epithelial cells results in pulmonary fibrosis

2003 ◽  
Vol 285 (3) ◽  
pp. L527-L539 ◽  
Author(s):  
Ying Dong Xu ◽  
Jiesong Hua ◽  
Alice Mui ◽  
Robert O'Connor ◽  
Gary Grotendorst ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Pulmonary Fibrosis ◽  
Transforming Growth Factor ◽  
Inflammatory Cells ◽  
Alveolar Epithelial Cells ◽  
Biologically Active ◽  
Aberrant Expression ◽  
Alveolar Epithelial ◽  
Fibrotic Lung Disease ◽  
Tgf Β1

Idiopathic pulmonary fibrosis (IPF) is a progressive fatal fibrotic lung disease. Transforming growth factor (TGF)-β1 is present in a biologically active conformation in the epithelial cells lining lesions with advanced IPF. To determine the role of aberrant expression of biologically active TGF-β1 by alveolar epithelial cells (AECs), the AECs of explanted normal rat lungs were transfected with the TGF-β1 gene using the retrovirus pMX-L-s223,225-TGF-β1. In situ hybridization using a digoxigenin-labeled cDNA of the puromycin resistance gene contained in the pMX demonstrated that pMX-L-s233,225-TGF-β1 was selectively transfected into AECs of the explants. Conditioned media overlying explants obtained 7 days after being treated with pMX-L-s223,225-TGF-β1 contained 14.5 ± 3.15 pg/ml of active TGF-β1. With the use of Masson's trichrome staining of explant sections obtained 14 days after transfection, there were lesions similar to those in IPF, characterized by type II AEC hyperplasia, interstitial thickening, extensive increase in interstitial and subepithelial collagen, an increase in the number of fibroblasts, and areas resembling fibroblast buds. Collagens I, III, IV, and V and fibronectin were increased in explants treated with pMX-L-s223,225-TGF-β1. The findings in the current study suggest that IPF may be a disorder of epithelial cells and not inflammatory cells.

scholarly journals Evidence for a Role of Transforming Growth Factor (TGF)-β1 in the Induction of Postglomerular Albuminuria in Diabetic Nephropathy

Diabetes ◽  
2007 ◽  
Vol 56 (2) ◽  
pp. 380-388 ◽  
Author(s):  
Leileata M. Russo ◽  
Elisabetta del Re ◽  
Dennis Brown ◽  
Herbert Y. Lin
Keyword(s):  
Diabetic Nephropathy ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Tgf Β1

JNK-dependent AP-1 activation is required for aristolochic acid-induced TGF-β1 synthesis in human renal proximal epithelial cells

2012 ◽  
Vol 302 (12) ◽  
pp. F1569-F1575 ◽  
Author(s):  
Hong-liang Rui ◽  
Yan-yan Wang ◽  
Hong Cheng ◽  
Yi-pu Chen
Keyword(s):  
Epithelial Cells ◽  
Transforming Growth Factor ◽  
Aristolochic Acid ◽  
Interstitial Fibrosis ◽  
Transforming Growth Factor Β1 ◽  
Tubulointerstitial Nephropathy ◽  
Jnk Signaling Pathway ◽  
Jnk Activation ◽  
Dose Dependent ◽  
Tgf Β1

Chronic aristolochic acid nephropathy (CAAN) is a chronic and progressive tubulointerstitial nephropathy characterized by extensive interstitial fibrosis. Aristolochic acid (AA) could induce overexpression of transforming growth factor-β1 (TGF-β1) in a human renal proximal tubule epithelial cells line (HKC), which has been implicated in the pathogenesis of CAAN. The present studies in HKC cells showed 1) AA could activate JNK in time- and dose-dependent manners and JNK inhibitor SP600125 could inhibit AA-induced TGF-β1 promoter activity and TGF-β1 synthesis; 2) AA-induced JNK activation and TGF-β1 synthesis were significantly inhibited by kinase-inactive mutants of MEKK4, MKK4, or MKK7; 3) AA could upregulate luciferase activity derived by a wild-type TGF-β1 promoter, but not by an AP-1 binding-deficient TGF-β1 promoter; and 4) AA could upregulate expression of c-Fos, phospho-c-Jun, and phospho-ATF2. The above data suggest AA-induced TGF-β1 overexpression in HKC cells may be mainly mediated by the JNK signaling pathway. Both the upstream kinases of JNK including MEKK4, MKK4, and MKK7, and the downstream transcription factor of JNK, AP-1, may also participate in this process.

TAT-mediated PRDX6 protein transduction protects against eye lens epithelial cell death and delays lens opacity

2008 ◽  
Vol 294 (3) ◽  
pp. C842-C855 ◽  
Author(s):  
Eri Kubo ◽  
Nigar Fatma ◽  
Yoshio Akagi ◽  
David R. Beier ◽  
Sanjay P. Singh ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Epithelial Cells ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Lens Epithelial Cell ◽  
Biologically Active ◽  
Lens Epithelial Cells ◽  
Protein Levels ◽  
Endogenous Antioxidant ◽  
Tgf Β1

A diminished level of endogenous antioxidant in cells/tissues is associated with reduced resistance to oxidative stress. Peroxiredoxin 6 (PRDX6), a protective molecule, regulates gene expression/function by controlling reactive oxygen species (ROS) levels. Using PRDX6 protein linked to TAT, the transduction domain from human immunodeficiency virus type 1 TAT protein, we demonstrated that PRDX6 was transduced into lens epithelial cells derived from rat or mouse lenses. The protein was biologically active, negatively regulating apoptosis and delaying progression of cataractogenesis by attenuating deleterious signaling. Lens epithelial cells from cataractous lenses bore elevated levels of ROS and were susceptible to oxidative stress. These cells harbored increased levels of active transforming growth factor (TGF)-β1 and of α-smooth muscle actin and βig-h3, markers for cataractogenesis. Importantly, cataractous lenses showed a 10-fold reduction in PRDX6 expression, whereas TGF-β1 mRNA and protein levels were elevated. The changes were reversed, and cataractogenesis was delayed when PRDX6 was supplied. Results suggest that delivery of PRDX6 can postpone cataractogenesis, and this should be an effective approach to delaying cataracts and other degenerative diseases that are associated with increased ROS.

scholarly journals De novo expression of podocyte proteins in parietal epithelial cells during experimental glomerular disease

2010 ◽  
Vol 298 (3) ◽  
pp. F702-F711 ◽  
Author(s):  
Takamoto Ohse ◽  
Michael R. Vaughan ◽  
Jeffrey B. Kopp ◽  
Ronald D. Krofft ◽  
Caroline B. Marshall ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Basement Membrane ◽  
Transforming Growth Factor ◽  
Wilms Tumor ◽  
Glomerular Disease ◽  
Double Positive ◽  
Specific Proteins ◽  
Parietal Epithelial Cells ◽  
Tgf Β1 ◽  
Glomerular Tuft

Studies have shown that certain cells of the glomerular tuft begin to express proteins considered unique to other cell types upon injury. Little is known about the response of parietal epithelial cells (PEC) to injury. To determine whether PECs change their phenotype upon injury to also express proteins traditionally considered podocyte specific, the following four models of glomerular disease were studied: the transforming growth factor (TGF)-β1 transgenic mouse model of global glomerulosclerosis, the adriamycin model of focal segmental glomerulosclerosis (FSGS), the anti-glomerular basement membrane (GBM) model of crescentic glomerulonephritis, and the passive Heymann nephritis model of membranous nephropathy. Double immunostaining was performed with antibodies to podocyte-specific proteins (synaptopodin and Wilms' tumor 1) and antibodies to PEC specific proteins (paired box gene 8 and claudin-1). No double staining was detected in normal mice. In contrast, the results showed a statistical increase in the number of cells attached to Bowman basement membrane that were double-positive for both podocyte/PEC proteins in TGF-β;1 transgenic, anti-GBM, and membranous animals. Double-positive cells for both podocyte and PEC proteins were also statistically increased in the glomerular tuft in TGF-β1 transgenic, anti-GBM, and FSGS mice. These results are consistent with glomerular cells coexpressing podocyte and PEC proteins in experimental glomerular disease, but not under normal circumstances.

Sign in / Sign up

Export Citation Format

Share Document