scholarly journals Molecular dissection of pro-fibrotic signaling identifies the mechanism underlying IL11-driven fibrosis gene translation, reveals non-specific effects of STAT3 and suggests a new mechanism of action for nintedanib

2021 ◽  
Author(s):  
Anissa A Widjaja ◽  
Sivakumar Viswanathan ◽  
Jinrui Dong ◽  
Brijesh K Singh ◽  
Jessie Tan ◽  
...  
Keyword(s):  
Er Stress ◽  
Mechanism Of Action ◽  
Protein Translation ◽  
Null Mouse ◽  
Autocrine Loop ◽  
Erk Activation ◽  
Specific Effects ◽  
Stat3 Phosphorylation ◽  
Dose Dependent ◽  
Pharmacologic Inhibition

In fibroblasts, TGFβ1 stimulates IL11 upregulation that leads to an autocrine loop of IL11-dependent pro-fibrotic protein translation. The signalling pathways downstream of IL11 are contentious and both STAT3 and ERK have been implicated. Here we show that TGFβ1- or IL11- induced ERK activation is consistently associated with fibrogenesis whereas STAT3 phosphorylation (pSTAT3) is unrelated to fibroblast activation. Surprisingly, recombinant human IL11, which has been used extensively in mouse experiments to infer STAT3 activity downstream of IL11, non-specifically increases pSTAT3 in Il11ra1 null mouse fibroblasts. Pharmacologic inhibition of STAT3 prevents TGFβ1-induced fibrogenesis but this effect was found to reflect fibroblast dysfunction due to severe proteotoxic ER stress. In contrast, inhibition of MEK/ERK prevented fibrosis in the absence of ER stress. TGFβ1-stimulated ERK/mTOR/P70RSK-driven protein translation was IL11-dependent and selectivity for pro-fibrotic protein synthesis was ascribed to an EPRS-related mechanism. In TGFβ1-stimulated fibroblasts, the anti-fibrotic drug nintedanib caused dose-dependent ER stress, reduced pSTAT/pERK and inhibited pro-fibrotic protein translation, similarly to generic STAT3 inhibitors or ER stressors. Pirfenidone, while anti-fibrotic, had no effect on ER stress whereas anti-IL11 inhibited the ERK/mTOR axis while reducing ER stress. These studies discount a specific role for STAT3 in pro-fibrotic signaling, suggest a novel mechanism of action for nintedanib and prioritise further the IL11 pathway as a therapeutic target for fibrosis.

scholarly journals Molecular Dissection of Pro-Fibrotic IL11 Signaling in Cardiac and Pulmonary Fibroblasts

2021 ◽  
Vol 8 ◽  
Author(s):  
Anissa A. Widjaja ◽  
Sivakumar Viswanathan ◽  
Dong Jinrui ◽  
Brijesh K. Singh ◽  
Jessie Tan ◽  
...  
Keyword(s):  
Er Stress ◽  
Signaling Pathways ◽  
Protein Translation ◽  
Null Mouse ◽  
Autocrine Loop ◽  
Erk Activation ◽  
Fibroblast Activation ◽  
Stat3 Phosphorylation ◽  
Dependent Protein ◽  
Dose Dependent

In fibroblasts, TGFβ1 stimulates IL11 upregulation that leads to an autocrine loop of IL11-dependent pro-fibrotic protein translation. The signaling pathways downstream of IL11, which acts via IL6ST, are contentious with both STAT3 and ERK implicated. Here we dissect IL11 signaling in fibroblasts and study IL11-dependent protein synthesis pathways in the context of approved anti-fibrotic drug mechanisms of action. We show that IL11-induced ERK activation drives fibrogenesis and while STAT3 phosphorylation (pSTAT3) is also seen, this appears unrelated to fibroblast activation. Ironically, recombinant human IL11, which has been used extensively in mouse experiments to infer STAT3 activity downstream of IL11, increases pSTAT3 in Il11ra1 null mouse fibroblasts. Unexpectedly, inhibition of STAT3 was found to induce severe proteotoxic ER stress, generalized fibroblast dysfunction and cell death. In contrast, inhibition of ERK prevented fibroblast activation in the absence of ER stress. IL11 stimulated an axis of ERK/mTOR/P70RSK protein translation and its selectivity for Collagen 1 synthesis was ascribed to an EPRS-regulated, ribosome stalling mechanism. Surprisingly, the anti-fibrotic drug nintedanib caused dose-dependent ER stress and lesser pSTAT3 expression. Pirfenidone had no effect on ER stress whereas anti-IL11 specifically inhibited the ERK/mTOR axis while reducing ER stress. These studies define the translation-specific signaling pathways downstream of IL11, intersect immune and metabolic signaling and reveal unappreciated effects of nintedanib.

Differential regulation by thyroid hormones of myosin heavy chain α and β mRNAs in the rat ventricular myocardium

1989 ◽  
Vol 122 (1) ◽  
pp. 193-200 ◽  
Author(s):  
N. K. Green ◽  
J. A. Franklyn ◽  
J. A. O. Ahlquist ◽  
M. D. Gammage ◽  
M. C. Sheppard
Keyword(s):  
Myosin Heavy Chain ◽  
Cardiac Myocytes ◽  
Heavy Chain ◽  
Ventricular Myocardium ◽  
Mhc Genes ◽  
Specific Effects ◽  
Dependent Inhibition ◽  
Dose Dependent

ABSTRACT The effect of tri-iodothyronine (T3) treatment on myocardial levels of α and β myosin heavy chain (MHC) mRNAs in the rat was defined in vivo and in vitro. Dose–response experiments were performed in intact hypothyroid and euthyroid rats; in addition, studies in vitro examined the effect of T3 on MHC mRNAs in neonatal cardiac myocytes in primary culture. Specific α and β MHC mRNAs were determined by Northern blot and dot hybridization to oligonucleotide probes complementary to the 3′ untranslated regions of the MHC genes. An increase in myocardial β MHC mRNA was demonstrated in hypothyroidism, accompanied by a reduction in α MHC mRNA. Marked differences in the sensitivity of α and β MHC mRNAs to T3 replacement were found; a dose-dependent increase in α mRNA was evident at 6 h after T3 treatment, in the absence of consistent effects on β mRNA, whereas 72 h after T3 replacement was commenced, stimulatory effects of T3 on α MHC mRNA, evident at all doses, were accompanied by a dose-dependent inhibition of β MHC mRNA. No effect of thyroid status on actin mRNA was found, indicating the specificity of MHC gene regulation. T3 treatment of cardiac myocytes in vitro exerted similar actions on MHC mRNAs to those found in vivo, with a more marked influence on α than β MHC mRNA. These studies of the action of T3 in vivo and in vitro have thus demonstrated specific effects of T3 on pretranslational regulation of the α and β MHC genes, influences which differ not only in terms of stimulation or inhibition, but also in magnitude of effect. Journal of Endocrinology (1989) 122, 193–200

scholarly journals Therapeutic effect and mechanism of action of quercetin in a rat model of osteoarthritis

2019 ◽  
Vol 48 (3) ◽  
pp. 030006051987346 ◽  
Author(s):  
Jun Zhang ◽  
Jing Yin ◽  
Daohong Zhao ◽  
Chaoran Wang ◽  
Yuhao Zhang ◽  
...  
Keyword(s):  
Therapeutic Effect ◽  
Mechanism Of Action ◽  
Rat Model ◽  
Dependent Manner ◽  
Nuclear Factor ◽  
Toll Like Receptor ◽  
Tnf Α ◽  
Dose Dependent ◽  
Light Chain Enhancer ◽  
Necrosis Factor

Objective To study the therapeutic effect and mechanism of action of quercetin in a rat model of osteoarthritis (OA). Methods The OA rat model was established by intra-articular injection of papain. Changes in knee diameter, toe volume and histopathology were measured. Levels of interleukin (IL)-β and tumor necrosis factor (TNF)-α were assessed by ELISA. Relative expression of Toll-like receptor (TLR)-4 and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) was evaluated by western blotting. Results Compared with rats treated with papain alone, changes in knee diameter, toe volume and Makin' s score were less apparent in OA rats treated with quercetin. Levels of serum IL-1β and TNF-α were also reduced in quercetin-treated OA rats. Expression of TLR-4 and NF-κB was significantly suppressed in a dose-dependent manner in quercetin-treated OA rats. Conclusion Quercetin exhibited a therapeutic effect in OA rats, which may be related to inhibition of IL-1β and TNF-α production via the TLR-4/NF-κB pathway.

JSI-124 (Cucurbitacin I) Inhibits Tumor Angiogenesis of Human Breast Cancer Through Reduction of STAT3 Phosphorylation

2015 ◽  
Vol 43 (02) ◽  
pp. 337-347 ◽  
Author(s):  
Jia Qi ◽  
Ge Xia ◽  
Cheng Rong Huang ◽  
Jian Xia Wang ◽  
Jian Zhang
Keyword(s):  
Breast Cancer ◽  
Cell Line ◽  
Tumor Angiogenesis ◽  
Tube Formation ◽  
Vital Role ◽  
Pathological Process ◽  
Autocrine Loop ◽  
Stat3 Signaling Pathway ◽  
Stat3 Phosphorylation

Breast cancer (BC) is the most frequently diagnosed type of cancer all over the world. Angiogenesis, a physiological or pathological process characterized by the sprouting of new blood vessels from existing vessels, plays a vital role in tumor nutrition. In this work, we used JSI-124 (Cucurbitacin I), a selective JAK/STAT3 signaling pathway inhibitor, to investigate the role of STAT3 in tumor angiogenesis of a human BC cell line in vitro. JSI-124 inhibited cell viability, proliferation, adhesion, migration and tube formation of a human BC cell line MDA-MB-468. After transfection with pMXs-Stat3C, a dominant active mutant, the inhibitory effects of JSI-124 on MDA-MB-468 were abolished. Furthermore, JSI-124 reduced the phosphorylation of STAT3. These results suggested that JSI-124 inhibited tumor angiogenesis of the human BC cell line in vitro through the reduction of STAT3 phosphorylation. In addition, JSI-124 could reduce VEGF transcription and secretion, suggesting that JSI-124 is also involved in the inhibition of the VEGF autocrine loop in the tumor microenvironment.

Methoxychlor stimulates the mouse lactoferrin gene promoter through a GC-rich element

2002 ◽  
Vol 80 (1) ◽  
pp. 23-26 ◽  
Author(s):  
Zhiping Zhang ◽  
Christina T Teng
Keyword(s):  
Estrogen Receptor ◽  
Gene Promoter ◽  
Null Mouse ◽  
Null Cell ◽  
Mouse Uterus ◽  
Natural Estrogens ◽  
Lactoferrin Gene ◽  
Epidermal Growth ◽  
Dose Dependent ◽  
Response Region

The lactoferrin gene in the mouse uterus is a target gene for natural estrogens and xenoestrogens. One of the xenoestrogens is methyoxychlor, an insecticide that displays both estrogenic and antiandrogenic activities. Recently, methyoxychlor was found to stimulate lactoferrin gene expression in the uterus of an estrogen receptor null mouse. The present study is designed to uncover the methoxychlor response region in the mouse lactoferrin gene promoter. A series of different lengths of the mouse lactoferrin gene 5' flanking region were linked to a chloramphenicol acetyltransferase (CAT) reporter construct and transfected into human endometrial carcinoma HEC-1B cells, an estrogen receptor null cell line, in order to examine the methoxychlor response. The transfected cells were treated with methoxychlor or the metabolite of methoxychlor, HPTE, and the CAT reporter activities were measured. Constructs that contain a mouse lactoferrin 5' region longer than 100 bp were activated more than twofold by both methoxychlor and HPTE. The activation of the CAT reporter by the chemicals was dose dependent and reached saturation. Additional deletion mutants within the 100-bp region were tested, and a GC-rich sequence (GC-II) that we have previously characterized as an epidermal growth factor (EGF) response element was identified to be the region for the methoxychlor response. GC-II binds Sp1, Sp3, and IKLF transcription factors, collaborates with the AP1/CREB binding element, and confers the EGF response. Whether the effect of methoxychlor requires the AP1/CREB binding element has yet to be established; however, the present finding provides an alternative signaling pathway for the xenoestrogens.Key words: xenoestrogen, methoxychlor, environmental, lactoferrin gene, promoter.

114 ENDOPLASMIC RETICULUM (ER) STRESS IN HYPOXIA-INDUCED DIABETES MELLITUS MODEL

2016 ◽  
Vol 28 (2) ◽  
pp. 187
Author(s):  
C. Ahn ◽  
D. Lee ◽  
K. P. Kim ◽  
M. H. Lee ◽  
E.-B. Jeung
Keyword(s):  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Er Stress ◽  
Pancreatic Beta Cells ◽  
Hypoxic Condition ◽  
Protein Translation ◽  
Ion Concentration ◽  
Cellular Stress Response ◽  
Stress Markers ◽  
Calbindin D9k

Endoplasmic reticulum (ER) regulates calcium ion concentration as a reservoir in the cell. ER stress is a cellular stress response related to the endoplasmic reticulum. At the initial stage of ER stress, ER tries to restore normal function by halting protein translation, degrading misfolded proteins, and increasing production of chaperones involved in protein folding. If ER fails to restore ER stress, ER stress can lead cells to apoptosis. To study the signaling between ER stress and calcium channels under ER-stressed circumstances, we designed a hypoxia-induced diabetic model. Nine-week-old male mice were chosen, maintained under hypoxic condition under 10% O2, 5% CO2 for 10 days, and the expression of ER stress markers and calcium channel gene expression were examined by real-time PCR. By maintaining hypoxic condition, the mice showed high glucose levels. Under this diabetic condition, in pancreatic beta cells, ER stress markers were elevated. This tendency showed an increase in calbindin-D9k KO mice. Chaperones such as calreticulin and calnexin were decreased, but in calbindin-D9k KO mice chaperone calnexin was not decreased. Interestingly, the calbindin-D9k KO normoxia mice showed increased glucose level compared with wild-type normoxia mice. Also, calnexin expression of pancreas was decreased in calbindin-D9k KO normoxia mice. This result indicates that pancreas cells were under endoplasmic reticulum stress. Taken together, calbindin may play an important role in endoplasmic reticulum stress in pancreas. This work was supported by the National Research Foundation of Korea (NRF) grant of Korean government (MEST) (No. 2013-010514).

Effects of Stearic Acid on Proliferation, Differentiation, Apoptosis, and Autophagy in Porcine Intestinal Epithelial Cells

2020 ◽  
Vol 20 (2) ◽  
pp. 157-166
Author(s):  
Yuan Yang ◽  
Jin Huang ◽  
Jianzhong Li ◽  
Huansheng Yang ◽  
Yulong Yin
Keyword(s):  
Cell Differentiation ◽  
Epithelial Cells ◽  
Stearic Acid ◽  
Er Stress ◽  
Intestinal Epithelial Cells ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
High Concentrations ◽  
Induced Apoptosis ◽  
Dose Dependent

Background: Stearic acid (SA), a saturated long-chain fatty acid consisting of 18 carbon atoms, is widely found in feed ingredients, such as corn, soybeans, and wheat. However, the roles of SA in the renewal of intestinal epithelial cells remain unclear. Methods and Results: In the present study, we found that 0.01-0.1 mM SA promoted IPEC-J2 cell differentiation and did not affect IPEC-J2 cell viability. In addition, the results showed that the viability of IPEC-J2 cells was inhibited by SA in a time- and dose-dependent manner at high concentrations. Flow cytometry and western blot analysis suggested that SA induced apoptosis, autophagy and ER stress in cells. In addition, the amounts of triglyceride were significantly increased upon challenge with SA. Moreover, the decrease in the viability of cells induced by SA could be attenuated by 4-PBA, an inhibitor of ER stress. Conclusion: In summary, SA accelerated IPEC-J2 cell differentiation at 0.01-0.1 mM. Furthermore, SA induced IPEC-J2 cell apoptosis and autophagy by causing ER stress.

scholarly journals Biochanin A, the Most Potent of 16 Isoflavones, Induces Relaxation of the Coronary Artery Through the Calcium Channel and cGMP-dependent Pathway

Planta Medica ◽  
2020 ◽  
Vol 86 (10) ◽  
pp. 708-716
Author(s):  
Thomas Migkos ◽  
Jana Pourová ◽  
Marie Vopršalová ◽  
Cyril Auger ◽  
Valérie Schini-Kerth ◽  
...  
Keyword(s):  
Coronary Arteries ◽  
Mechanism Of Action ◽  
Biochanin A ◽  
Dependent Manner ◽  
Major Mechanism ◽  
Camp Pathway ◽  
Clinical Interest ◽  
Series Of Experiments ◽  
Dose Dependent ◽  
Dependent Pathway

AbstractThe dietary intake of flavonoids seems to be inversely related to cardiovascular mortality. The consumption of isoflavonoids is increasing in the general population, especially due to the use of food supplements and a variety of isoflavonoid-rich foods. However, detailed studies on the vascular influence of individual pure isoflavonoids are mostly missing. For this study, 16 isoflavonoids were initially screened for their vasorelaxant properties on rat aortas. The 2 most potent of them, biochanin A and glycitein, were further tested for the mechanism of action on porcine coronary arteries. They both induced an endothelium independent vascular relaxation, with EC50 below 6 and 17 µM, respectively. Biochanin A, but not glycitein, was able to block the vasoconstriction caused by KCl, CaCl2, serotonin, and U46619 in a dose-dependent manner. Another series of experiments suggested that the major mechanism of action of biochanin A was the inhibition of L-type calcium channels. Moreover, biochanin A in relatively small concentrations (2 – 4 µM) interfered with the cGMP, but not cAMP, pathway in isolated coronary arteries. These results indicate that some isoflavonoids, in particular biochanin A, are able to have vasodilatory effects in micromolar concentrations, which is of potential clinical interest for the management of cardiovascular pathologies.

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