scholarly journals Transforming growth factor-β1-induced N-cadherin drives cell–cell communication through connexin43 in osteoblast lineage

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Yueyi Yang ◽  
Wenjing Liu ◽  
JieYa Wei ◽  
Yujia Cui ◽  
Demao Zhang ◽  
...  

AbstractGap junction (GJ) has been indicated to have an intimate correlation with adhesion junction. However, the direct interaction between them partially remains elusive. In the current study, we aimed to elucidate the role of N-cadherin, one of the core components in adhesion junction, in mediating connexin 43, one of the functional constituents in gap junction, via transforming growth factor-β1(TGF-β1) induction in osteoblasts. We first elucidated the expressions of N-cadherin induced by TGF-β1 and also confirmed the upregulation of Cx43, and the enhancement of functional gap junctional intercellular communication (GJIC) triggered by TGF-β1 in both primary osteoblasts and MC3T3 cell line. Colocalization analysis and Co-IP experimentation showed that N-cadherin interacts with Cx43 at the site of cell–cell contact. Knockdown of N-cadherin by siRNA interference decreased the Cx43 expression and abolished the promoting effect of TGF-β1 on Cx43. Functional GJICs in living primary osteoblasts and MC3T3 cell line were also reduced. TGF-β1-induced increase in N-cadherin and Cx43 was via Smad3 activation, whereas knockdown of Smad3 signaling by using siRNA decreased the expressions of both N-cadherin and Cx43. Overall, these data indicate the direct interactions between N-cadherin and Cx43, and reveal the intervention of adhesion junction in functional gap junction in living osteoblasts.

2018 ◽  
Vol 38 (6) ◽  
Author(s):  
Wenjing Liu ◽  
Yujia Cui ◽  
Jianxun Sun ◽  
Linyi Cai ◽  
Jing Xie ◽  
...  

Connexin 43 (Cx43)-mediated gap junctional intercellular communication (GJIC) has been shown to be important in regulating multiple functions of bone cells. Transforming growth factor-β1 (TGF-β1) exhibited controversial effects on the expression of Cx43 in different cell types. To date, the effect of TGF-β1 on the Cx43 expression of osteocytes is still unknown. In the present study, we detected the expression of TGF-β1 in osteocytes and bone tissue, and then used recombinant mouse TGF-β1 to elucidate its effect on gap junctions (GJs) of osteocytes. Our data indicated that TGF-β1 up-regulated both mRNA and protein expression of Cx43 in osteocytes. Together with down-regulation of Cx43 expression after being treated with TGF-β type I receptor inhibitor Repsox, we deduced that TGF-β1 can positively regulate Cx43 expression in osteocytes. Thus we next focussed on the downstream signals of TGF-β and found that TGF-β1-mediated smads, Smad3 and Smad4, to translocate into nucleus. These translocated signal proteins bind to the promoter of Gja1 which was responsible for the changed expression of Cx43. The present study provides evidence that TGF-β1 can enhance GJIC between osteocytes through up-regulating Cx43 expression and the underlying mechanism involved in the activation of Smad-dependent pathway.


Cells ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 185 ◽  
Author(s):  
Jingwen Yin ◽  
Hsun-Ming Chang ◽  
Yuyin Yi ◽  
Yuanqing Yao ◽  
Peter C.K. Leung

Glial cell line-derived neurotrophic factor (GDNF) is expressed at a high level in the human ovary and GDNF signaling is involved in the direct control of follicular activation and oocyte maturation. Transforming growth factor-β1 (TGF-β1) plays an important role in the regulation of various ovarian functions. Furin is an intracellular serine endopeptidase of the subtilisin family that is closely associated with the activation of multiple protein precursors. Despite the important roles of GDNF and TGF-β1 in the regulation of follicular development, whether TGF-β is able to regulate the expression and production of GDNF in human granulosa cells remains to be determined. The aim of this study was to investigate the effect of TGF-β1 on the production of GDNF and its underlying mechanisms in human granulosa-lutein (hGL) cells. We used two types of hGL cells (primary hGL cells and an established immortalized hGL cell line, SVOG cells) as study models. Our results show that TGF-β1 significantly induced the expression of GDNF and furin, which, in turn, increased the production of mature GDNF. Using a dual inhibition approach combining RNA interference and kinase inhibitors against cell signaling components, we showed that the TβRII type II receptor and ALK5 type I receptor are the principal receptors that mediated TGF-β1-induced cellular activity in hGL cells. Additionally, Sma- and Mad-related protein (SMAD)3 and SMAD4 are the downstream signaling transducers that mediate the biological response induced by TGF-β1. Furthermore, furin is the main proprotein convertase that induces the production of GDNF. These findings provide additional regulatory mechanisms by which an intrafollicular factor influences the production of another growth factor through a paracrine or autocrine interaction in hGL cells.


1995 ◽  
Vol 8 (2) ◽  
pp. 67-77 ◽  
Author(s):  
P. Mitlianga ◽  
G. Germanidis ◽  
H. M. Moutsopoulos ◽  
G. K. Papadopoulos

The rat pancreatic β cell line RIN-5AH was treated with the cytokines IL-1 (α and β), TNFα and TGF-β1, in order to examine at the clonal level the reported mostly cytotoxic effects of IL-1, on isolated islets of Langerhans and islet cell preparations. In contrast to what has been previously reported for whole islets and islet cell preparations we find that IL-1 (α or β) is not cytotoxic to the RIN-5AH cells in logarithmic growth phase to any extent, even at very high cytokine concentrations (125 nM). Furthermore, TNFα does not in any way potentiate IL-1 cytotoxicity. Transforming growth factor-β1 (TGF-β1) at concentrations of 80 pM to 2 nM, has a potentiating effect on IL-1 cytotoxicity (conc. 5 nM) for this clonal cell line. The effect is proportional to the level of TGF-β1 present and is exerted regardless of the IL-1 isoform used. The effects of the various cytokines, alone or in combination, were only observed at high (25 mM) glucose concentrations, and no such effects were observed at the physiological (5 mM) glucose concentration. Furthermore the combination of TGF-β1 and IL-1 inhibits the release of insulin by these cells, whereas either cytokine alone has no effect. We conclude that the RIN-5AH cells in showing little cytotoxic/cytostatic response to IL-1 are responding more as isolated β cells than as cells within islets. The potentiation of the action of IL-1 by TGF-β1 on these cells is a matter of further investigation.


2021 ◽  
Vol 22 (6) ◽  
pp. 2952
Author(s):  
Tzu-Yu Hou ◽  
Shi-Bei Wu ◽  
Hui-Chuan Kau ◽  
Chieh-Chih Tsai

Transforming growth factor-β1 (TGF-β1)-induced myofibroblast transdifferentiation from orbital fibroblasts is known to dominate tissue remodeling and fibrosis in Graves’ ophthalmopathy (GO). However, the signaling pathways through which TGF-β1 activates Graves’ orbital fibroblasts remain unclear. This study investigated the role of the mitogen-activated protein kinase (MAPK) pathway in TGF-β1-induced myofibroblast transdifferentiation in human Graves’ orbital fibroblasts. The MAPK pathway was assessed by measuring the phosphorylation of p38, c-Jun N-terminal kinase (JNK), and extracellular-signal-regulated kinase (ERK) by Western blots. The expression of connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), and fibronectin representing fibrogenesis was estimated. The activities of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) responsible for extracellular matrix (ECM) metabolism were analyzed. Specific pharmacologic kinase inhibitors were used to confirm the involvement of the MAPK pathway. After treatment with TGF-β1, the phosphorylation levels of p38 and JNK, but not ERK, were increased. CTGF, α-SMA, and fibronectin, as well as TIMP-1 and TIMP-3, were upregulated, whereas the activities of MMP-2/-9 were inhibited. The effects of TGF-β1 on the expression of these factors were eliminated by p38 and JNK inhibitors. The results suggested that TGF-β1 could induce myofibroblast transdifferentiation in human Graves’ orbital fibroblasts through the p38 and JNK pathways.


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