scholarly journals Matrix-bound AGEs enhance TGFβ2-mediated mesenchymal transition of lens epithelial cells via the noncanonical pathway: implications for secondary cataract formation

2018 ◽  
Vol 475 (8) ◽  
pp. 1427-1440 ◽  
Author(s):  
Mi-Hyun Nam ◽  
Ram H. Nagaraj
Keyword(s):  
Epithelial Cells ◽  
P38 Mapk ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Lens Epithelial Cells ◽  
Dependent Manner ◽  
Mesenchymal Transition ◽  
Noncanonical Pathway ◽  
Αb Crystallin

Advanced glycation end products (AGEs) are post-translational modifications formed from the reaction of reactive carbonyl compounds with amino groups in proteins. Our laboratory has previously shown that AGEs in extracellular matrix (ECM) proteins promote TGFβ2 (transforming growth factor-beta 2)-mediated epithelial-to-mesenchymal transition (EMT) of lens epithelial cells (LECs), which could play a role in fibrosis associated with posterior capsule opacification. We have also shown that αB-crystallin plays an important role in TGFβ2-mediated EMT of LECs. Here, we investigated the signaling mechanisms by which ECM-AGEs enhance TGFβ2-mediated EMT in LECs. We found that in LECs cultured on AGE-modified basement protein extract (AGE-BME), TGFβ2 treatment up-regulated the mesenchymal markers α-SMA (α-smooth muscle actin) and αB-crystallin and down-regulated the epithelial marker E-cadherin more than LECs cultured on unmodified BME and treated with TGFβ2. Using a Multiplex Assay, we found that AGE-BME significantly up-regulated the noncanonical pathway by promoting phosphorylation of ERK (extracellular signal-regulated kinases), AKT, and p38 MAPK (mitogen-activated protein kinases) during TGFβ2-mediated EMT. This EMT response was strongly suppressed by inhibition of AKT and p38 MAPK phosphorylation. The AKT inhibitor LY294002 also suppressed TGFβ2-induced up-regulation of nuclear Snail and reduced phosphorylation of GSK3β. Inhibition of Snail expression suppressed TGFβ2-mediated α-SMA expression. αB-Crystallin was up-regulated in an AKT-dependent manner during AGE-BME/TGFβ2-mediated EMT in LECs. The absence of αB-crystallin in LECs suppressed TGFβ2-induced GSK3β phosphorylation, resulting in lower Snail levels. Taken together, these results show that ECM-AGEs enhance the TGFβ2-mediated EMT response through activation of the AKT/Snail pathway, in which αB-crystallin plays an important role as a linker between the TGFβ2 and AGE-mediated signaling pathways.

Transforming growth factor-β2-mediated mesenchymal transition in lens epithelial cells is repressed in the absence of RAGE

2021 ◽  
Vol 478 (12) ◽  
pp. 2285-2296
Author(s):  
Mi-Hyun Nam ◽  
Mina B. Pantcheva ◽  
Johanna Rankenberg ◽  
Ram H. Nagaraj
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Knockout Mice ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Lens Epithelial Cells ◽  
Wild Type ◽  
Mesenchymal Transition ◽  
Smad Signaling ◽  
Transforming Growth Factor Β2

Transforming growth factor-β2 (TGFβ2)-mediated epithelial to mesenchymal transition (EMT) in lens epithelial cells (LECs) has been implicated in fibrosis associated with secondary cataracts. In this study, we investigated whether the receptor for advanced glycation end products (RAGE) plays a role in TGFβ2-mediated EMT in LECs. Unlike in the LECs from wild-type mice, TGFβ2 failed to elicit an EMT response in LECs from RAGE knockout mice. The lack of RAGE also diminished TGFβ2-mediated Smad signaling. In addition, treatment with TGFβ2 increased IL-6 levels in LECs from wild-type mice but not in those from RAGE knockout mice. Treatment of human LECs with the RAGE inhibitor FPS-ZM1 reduced TGFβ2-mediated Smad signaling and the EMT response. Unlike that in wild-type lenses, the removal of fiber cell tissue in RAGE knockout lenses did not result in elevated levels of α-smooth muscle actin (α-SMA), fibronectin (FN), and integrin β1 in capsule-adherent LECs. Taken together, these results suggest that TGFβ2 signaling is intricately linked to RAGE. Targeting RAGE could be explored as a therapeutic strategy against secondary cataracts.

scholarly journals αB-crystallin is essential for the TGF-β2-mediated epithelial to mesenchymal transition of lens epithelial cells

2016 ◽  
Vol 473 (10) ◽  
pp. 1455-1469 ◽  
Author(s):  
Rooban B. Nahomi ◽  
Mina B. Pantcheva ◽  
Ram H. Nagaraj
Keyword(s):  
Growth Factor ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Therapeutic Target ◽  
Epithelial To Mesenchymal Transition ◽  
Transforming Growth Factor ◽  
Lens Epithelial Cell ◽  
Lens Epithelial Cells ◽  
Mesenchymal Transition ◽  
Αb Crystallin

We found that αB-crystallin promoted transforming growth factor (TGF)-β2-induced epithelial to mesenchymal transition (EMT) in lens epithelial cell (LEC) and its depletion resulted in reduced EMT in cultured LEC and in lensectomized mice. αB-Crystallin could be a therapeutic target to block secondary cataract.

scholarly journals Aspirin inhibits TGFβ2-induced epithelial to mesenchymal transition of lens epithelial cells: selective acetylation of K56 and K122 in histone H3

2020 ◽  
Vol 477 (1) ◽  
pp. 75-97 ◽  
Author(s):  
Mi-Hyun Nam ◽  
Andrew J.O. Smith ◽  
Mina B. Pantcheva ◽  
Ko Uoon Park ◽  
Joseph A. Brzezinski ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Epithelial To Mesenchymal Transition ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Histone H3 ◽  
Posterior Capsule ◽  
Human Lens ◽  
Lens Epithelial Cells ◽  
Promoter Regions ◽  
Mesenchymal Transition

Posterior capsule opacification (PCO) is a complication after cataract surgery that can disrupt vision. The epithelial to mesenchymal transition (EMT) of lens epithelial cells (LECs) in response to transforming growth factor β2 (TGFβ2) has been considered an obligatory mechanism for PCO. In this study, we tested the efficacy of aspirin in inhibiting the TGFβ2-mediated EMT of human LECs, LECs in human lens capsular bags, and lensectomized mice. In human LECs, the levels of the EMT markers α-smooth muscle actin (α-SMA) and fibronectin were drastically reduced by treatment with 2 mM aspirin. Aspirin also halted the EMT response of TGFβ2 when introduced after EMT initiation. In human capsular bags, treatment with 2 mM aspirin significantly suppressed posterior capsule wrinkling and the expression α-SMA in capsule-adherent LECs. The inhibition of TGFβ2-mediated EMT in human LECs was not dependent on Smad phosphorylation or MAPK and AKT-mediated signaling. We found that aspirin significantly increased the acetylation of K56 and K122 in histone H3 of human LECs. Chromatin immunoprecipitation assays using acetyl-H3K56 or acetyl-H3K122 antibody revealed that aspirin blocked the TGFβ2-induced acetylation of H3K56 and H3K122 at the promoter regions of ACTA2 and COL1A1. After lensectomy in mice, we observed an increase in the proliferation and α-SMA expression of the capsule-adherent LECs, which was ameliorated by aspirin administration through drinking water. Taken together, our results showed that aspirin inhibits TGFβ2-mediated EMT of LECs, possibly from epigenetic down-regulation of EMT-related genes.

scholarly journals The TGFβ-induced phosphorylation and activation of p38 mitogen-activated protein kinase is mediated by MAP3K4 and MAP3K10 but not TAK1

Open Biology ◽  
2013 ◽  
Vol 3 (6) ◽  
pp. 130067 ◽  
Author(s):  
Gopal P. Sapkota
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Transforming Growth Factor Beta ◽  
Molecular Mechanisms ◽  
Epithelial To Mesenchymal Transition ◽  
Transforming Growth Factor ◽  
Mitogen Activated Protein Kinase ◽  
Mapk Phosphorylation ◽  
Mesenchymal Transition ◽  
Mitogen Activated Protein

The signalling pathways downstream of the transforming growth factor beta (TGFβ) family of cytokines play critical roles in all aspects of cellular homeostasis. The phosphorylation and activation of p38 mitogen-activated protein kinase (MAPK) has been implicated in TGFβ-induced epithelial-to-mesenchymal transition and apoptosis. The precise molecular mechanisms by which TGFβ cytokines induce the phosphorylation and activation of p38 MAPK are unclear. In this study, I demonstrate that TGFβ-activated kinase 1 (TAK1/MAP3K7) does not play a role in the TGFβ-induced phosphorylation and activation of p38 MAPK in MEFs and HaCaT keratinocytes. Instead, RNAi -mediated depletion of MAP3K4 and MAP3K10 results in the inhibition of the TGFβ-induced p38 MAPK phosphorylation. Furthermore, the depletion of MAP3K10 from cells homozygously knocked-in with a catalytically inactive mutant of MAP3K4 completely abolishes the TGFβ-induced phosphorylation of p38 MAPK, implying that among MAP3Ks, MAP3K4 and MAP3K10 are sufficient for mediating the TGFβ-induced activation of p38 MAPK.

scholarly journals Microparticles as Potential Mediators of High Glucose-Induced Renal Cell Injury

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 348 ◽  
Author(s):  
Ravindran ◽  
Pasha ◽  
Agouni ◽  
Munusamy
Keyword(s):  
Er Stress ◽  
Signaling Pathways ◽  
Transforming Growth Factor Beta ◽  
High Glucose ◽  
Cell Injury ◽  
Transforming Growth Factor ◽  
Nuclear Translocation ◽  
Epithelial Mesenchymal Transition ◽  
Smooth Muscle Actin ◽  
Mesenchymal Transition

Diabetic nephropathy (DN) is the most common cause of chronic kidney disease worldwide. Activation of signaling pathways such as the mammalian target of rapamycin (mTOR), extracellular signal-regulated kinases (ERK), endoplasmic reticulum (ER) stress, transforming growth factor-beta (TGF-β), and epithelial-mesenchymal transition (EMT), are thought to play a significant role in the etiology of DN. Microparticles (MPs), the small membrane vesicles containing bioactive signals shed by cells upon activation or during apoptosis, are elevated in diabetes and were identified as biomarkers in DN. However, their exact role in the pathophysiology of DN remains unclear. Here, we examined the effect of MPs shed from renal proximal tubular cells (RPTCs) exposed to high glucose conditions on naïve RPTCs in vitro. Our results showed significant increases in the levels of phosphorylated forms of 4E-binding protein 1 and ERK1/2 (the downstream targets of mTOR and ERK pathways), phosphorylated-eIF2α (an ER stress marker), alpha smooth muscle actin (an EMT marker), and phosphorylated-SMAD2 and nuclear translocation of SMAD4 (markers of TGF-β signaling). Together, our findings indicate that MPs activate key signaling pathways in RPTCs under high glucose conditions. Pharmacological interventions to inhibit shedding of MPs from RPTCs might serve as an effective strategy to prevent the progression of DN.

The anti-inflammatory and anti-fibrotic effects of tadalafil in thioacetamide-induced liver fibrosis in rats

2018 ◽  
Vol 96 (12) ◽  
pp. 1308-1317 ◽  
Author(s):  
Heba M. Mansour ◽  
Abeer A.A. Salama ◽  
Rania M. Abdel-Salam ◽  
Naglaa A. Ahmed ◽  
Noha N. Yassen ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Inflammatory Cytokines ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Interleukin 1 ◽  
Health Concern ◽  
Dependent Manner ◽  
Serum Transaminases ◽  
Anti Inflammatory

Liver fibrosis is a health concern that leads to organ failure mediated via production of inflammatory cytokines and fibrotic biomarkers. This study aimed to explore the protective effect of tadalafil, a phosphodiesterase-5 inhibitor, against thioacetamide (TAA)-induced liver fibrosis. Fibrosis was induced by administration of TAA (200 mg/kg, i.p.) twice weekly for 6 weeks. Serum transaminases activities, liver inflammatory cytokines, fibrotic biomarkers, and liver histopathology were assessed. TAA induced marked histopathological changes in liver tissues coupled with elevations in serum transaminases activities. Furthermore, hepatic content of nitric oxide and tumor necrosis factor-alpha, interleukin-6, and interleukin-1 beta were elevated, together with a reduction of interleukin-10 in the liver. In addition, TAA increased hepatic contents of transforming growth factor-beta, hydroxyproline, alpha-smooth muscle actin, and gene expression of collagen-1. Pretreatment with tadalafil protected against TAA-induced liver fibrosis, in a dose-dependent manner, as proved by the alleviation of inflammatory and fibrotic biomarkers. The effects of tadalafil were comparable with that of silymarin, a natural antioxidant, and could be assigned to its anti-inflammatory and anti-fibrotic properties.

scholarly journals Identification of drivers of breast cancer invasion by secretome analysis: insight into CTGF signaling

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Johanna W. Hellinger ◽  
Franziska Schömel ◽  
Judith V. Buse ◽  
Christof Lenz ◽  
Gerd Bauerschmitz ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Growth Factor ◽  
Cancer Cells ◽  
Cell Invasion ◽  
Transforming Growth Factor Beta ◽  
Breast Cancer Cells ◽  
Transforming Growth Factor ◽  
Tissue Growth ◽  
Dependent Manner ◽  
Mesenchymal Transition

Abstract An altered consistency of tumor microenvironment facilitates the progression of the tumor towards metastasis. Here we combine data from secretome and proteome analysis using mass spectrometry with microarray data from mesenchymal transformed breast cancer cells (MCF-7-EMT) to elucidate the drivers of epithelial-mesenchymal transition (EMT) and cell invasion. Suppression of connective tissue growth factor (CTGF) reduced invasion in 2D and 3D invasion assays and expression of transforming growth factor-beta-induced protein ig-h3 (TGFBI), Zinc finger E-box-binding homeobox 1 (ZEB1) and lysyl oxidase (LOX), while the adhesion of cell-extracellular matrix (ECM) in mesenchymal transformed breast cancer cells is increased. In contrast, an enhanced expression of CTGF leads to an increased 3D invasion, expression of fibronectin 1 (FN1), secreted protein acidic and cysteine rich (SPARC) and CD44 and a reduced cell ECM adhesion. Gonadotropin-releasing hormone (GnRH) agonist Triptorelin reduces CTGF expression in a Ras homolog family member A (RhoA)-dependent manner. Our results suggest that CTGF drives breast cancer cell invasion in vitro and therefore could be an attractive therapeutic target for drug development to prevent the spread of breast cancer.

Heptachlor-induced epithelial to mesenchymal transition in HK-2 cells mediated via TGF-β1/Smad signalling

2019 ◽  
Vol 38 (5) ◽  
pp. 567-577 ◽  
Author(s):  
N Singh ◽  
M Siddarth ◽  
R Ghosh ◽  
AK Tripathi ◽  
BD Banerjee
Keyword(s):  
Epithelial To Mesenchymal Transition ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Dependent Manner ◽  
Mesenchymal Transition ◽  
Epithelial Marker ◽  
Proximal Tubular ◽  
Renal Proximal Tubular ◽  
Smad 3 ◽  
Tgf Β1

This study investigated the effect of heptachlor-induced oxidative stress (OS) on transforming growth factor (TGF)-β1-mediated epithelial to mesenchymal transition (EMT) in human renal proximal tubular epithelial (HK-2) cells. Following treatment of HK-2 cells with an increasing concentration of heptachlor (0.01–10 µM) for 24 h, the intracellular reactive oxygen species and malondialdehyde level increased, whereas the glutathione-s-hydroxylase (GSH) level declined significantly in a dose-dependent manner. Pretreatment with N-acetyl cysteine attenuates the heptachlor-induced OS. In this study, we have shown that heptachlor-induced OS regulates the mRNA expression of TGF-β1-mediated Smad signalling genes accompanied by increased nuclear localization of phosphorylated Smad-2 and phosphorylated Smad-3. Furthermore, the m-RNA and protein level of epithelial marker, that is, E-cadherin decreased while the mesenchymal marker, that is, α-smooth muscle actin increased in heptachlor exposed HK-2 cells. In conclusion, heptachlor-induced OS might be responsible for the activation of TGF-β1/Smad signalling which ultimately leads to renal damage by means of EMT.

scholarly journals Long Noncoding RNA NEAT1 Regulates TGF-β2-Induced Epithelial-Mesenchymal Transition of Lens Epithelial Cells through the miR-34a/Snail1 and miR-204/Zeb1 Pathways

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Ning Dong
Keyword(s):  
Epithelial Cells ◽  
Long Noncoding Rna ◽  
Noncoding Rna ◽  
Rna Binding ◽  
Epithelial Mesenchymal Transition ◽  
Luciferase Assay ◽  
Lens Epithelial Cells ◽  
Dependent Manner ◽  
Mesenchymal Transition ◽  
Anterior Subcapsular Cataract

The aim of this study was to explore whether the long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1)/miR-34a/Snail1 and NEAT1/miR-204/Zeb1 pathways are involved in epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs). Primary human LECs (HLECs) were separated and cultured. Our results identified that TGF-β2 induces NEAT1 overexpression in a dose-dependent manner and a time-dependent manner. Additionally, TGF-β2 induced downregulation of E-cadherin and upregulation of fibronectin in primary HLECs through a NEAT1-dependent mechanism. Microarray analysis showed that NEAT1 overexpression inhibited the miR-34a and miR-204 levels in the LECs. The expression of miR-34a and miR-204 was decreased, and the levels of Snail1 and Zeb1 were elevated in human posterior capsule opacification- (PCO-) attached LECs and the LECs obtained from anterior subcapsular cataract (ASC) by quantitative RT-PCR (qRT-PCR). Mechanistic studies revealed that NEAT1 negatively regulates miR-34a or miR-204, and miR-34a or miR-204 directly targets Snail1 or Zeb1 by luciferase assay and RNA-binding protein immunoprecipitation assay, respectively. Overall, the NEAT1/miR-34a/Snail1 and NEAT1/miR-204/Zeb1 pathways are involved in TGF-β2-induced EMT of HLECs. In summary, TGF-β2 induces NEAT1 overexpression, which in turn suggests that NEAT1 acts as a ceRNA targeting Snail1 or Zeb1 by binding miR-34a or miR-204, and promotes the progression of EMT of LECs.

Sign in / Sign up

Export Citation Format

Share Document