Effects of bone morphogenetic protein 4, gremlin, and connective tissue growth factor on estradiol and progesterone production by bovine granulosa cells

Author(s):  
L J Spicer ◽  
L F Schutz ◽  
P Y Aad

Abstract Bone morphogenetic proteins (BMP) are members of the transforming growth factor β (TGFβ) family of proteins that have been implicated in the paracrine regulation of granulosa cell (GC) function, but whether responses to BMPs change with follicular size or interact with connective tissue growth factor (CTGF) or BMP antagonists (e.g., gremlin) to directly affect GC function of cattle is unknown. Therefore, to determine the effects of BMP4 on proliferation and steroidogenesis of GC and its interaction with gremlin or CTGF, experiments were conducted using bovine GC cultures. In vitro, BMP4 (30 ng/mL) inhibited (P < 0.05) follicle-stimulating hormone (FSH) plus insulin-like growth factor 1 (IGF1)-induced progesterone and estradiol production by large- and small-follicle GC but the inhibitory effect of BMP4 on estradiol production was much more pronounced in large-follicle GC. In small-follicle GC, BMP4 had no effect (P > 0.10) on IGF1-induced proliferation, but gremlin inhibited (P < 0.05) cell proliferation and estradiol and progesterone production in IGF1 plus FSH-treated GC. In large-follicle GC, BMP4 (10-30 ng/mL) increased (P < 0.05) GC numbers and gremlin (100 ng/mL) blocked this effect. In large-follicle GC, CTGF inhibited (P < 0.05) FSH plus IGF1-induced progesterone and estradiol production, and CTGF blocked the stimulatory effect of BMP4 on GC proliferation. These results indicate that BMP4, gremlin, and CTGF inhibit GC aromatase activity and progesterone production. Also, the stimulatory effect of BMP4 on GC proliferation and the inhibitory effects of BMP4 on GC steroidogenesis are more pronounced in large versus small follicles.

2005 ◽  
Vol 288 (4) ◽  
pp. F800-F809 ◽  
Author(s):  
W. Qi ◽  
S. Twigg ◽  
X. Chen ◽  
T. S. Polhill ◽  
P. Poronnik ◽  
...  

Matrix accumulation in the renal tubulointerstitium is predictive of a progressive decline in renal function. Transforming growth factor-β1 (TGF-β1) and, more recently, connective tissue growth factor (CTGF) are recognized to play key roles in mediating the fibrogenic response, independently of the primary renal insult. Further definition of the independent and interrelated effects of CTGF and TGF-β1 is critical for the development of effective antifibrotic strategies. CTGF (20 ng/ml) induced fibronectin and collagen IV secretion in primary cultures of human proximal tubule cells (PTC) and cortical fibroblasts (CF) compared with control values ( P < 0.005 in all cases). This effect was inhibited by neutralizing antibodies to either TGF-β or to the TGF-β type II receptor (TβRII). TGF-β1 induced a greater increase in fibronectin and collagen IV secretion in both PTC ( P < 0.01) and CF ( P < 0.01) compared with that observed with CTGF alone. The combination of TGF-β1 and CTGF was additive in their effects on both PTC and CF fibronectin and collagen IV secretion. TGF-β1 (2 ng/ml) stimulated CTGF mRNA expression within 30 min, which was sustained for up to 24 h, with a consequent increase in CTGF protein ( P < 0.05), whereas CTGF had no effect on TGF-β1 mRNA or protein expression. TGF-β1 (2 ng/ml) induced phosphorylated (p)Smad-2 within 15 min, which was sustained for up to 24 h. CTGF had a delayed effect on increasing pSmad-2 expression, which was evident at 24 h. In conclusion, this study has demonstrated the key dependence of the fibrogenic actions of CTGF on TGF-β. It has further uniquely demonstrated that CTGF requires TGF-β, signaling through the TβRII in both PTCs and CFs, to exert its fibrogenic response in this in vitro model.


2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Nicole L Rosin ◽  
Jean-François Légaré ◽  
Timothy D Lee

Background: AngiotensinII (AngII) exposure to rodents is a common model of fibrosis, characterized by hypertension, hypertrophy and eventual deposition of excess extracellular matrix (ECM) proteins resulting in organ dysfunction. We have previously shown that cellular infiltration of bone marrow derived progenitor cells (fibrocytes) occurs prior to ECM deposition and is associated with production of the connective tissue growth factor (CTGF) and transforming growth factor beta (TGF-β). The objective of this project was to characterize the role of CTGF in promoting fibrocyte recruitment and subsequent fibrosis after AngII exposure. Methods: Mice were treated with AngII or saline using an osmotic mini-pump at 2.8mg/kg/day. After 6hr to 7d hearts were excised and embedded in paraffin or prepared for mRNA isolation. Immunohistochemistry was used to determine extent and localization of CTGF protein. Quantitative RT-PCR was used to determine relative CTGF and TGF-β mRNA levels. Primary cardiomyocyte and fibrocyte cultures were isolated from neonatal or 3d AngII exposed animals respectively. Primary cultures were stimulated to determine the source (qRT-PCR) and function (proliferation, migration and differentiation) of CTGF. Results: In animals exposed to AngII, CTGF mRNA peaked the earliest at 6hr (21-fold; p<0.01) when compared to TGFbeta, which peaked at 3d (5-fold; p<0.05). Concurrent CTGF protein expression was evident by 3d of AngII exposure and appeared localized to the cardiomyocytes. Findings were confirmed using isolated cardiomyocytes, which significantly increased expression of CTGF in response to AngII (2-fold; p<0.05). While CTGF did not promote fibrocyte migration in transwell chamber assay it promoted significant fibrocyte proliferation in vitro (2-fold; p<0.05). Conclusion: We provide strong evidence that AngII exposure first results in the production of CTGF by cardiomyocytes. Furthermore, we have shown that CTGF does not promote migration as a chemokine but instead contributes to proliferation of fibrocytes once recruited from the bone marrow into the myocardium.


PLoS ONE ◽  
2015 ◽  
Vol 10 (8) ◽  
pp. e0133689 ◽  
Author(s):  
Fabio A. Mendes ◽  
Juliana M. Coelho Aguiar ◽  
Suzana A. Kahn ◽  
Alice H. Reis ◽  
Luiz Gustavo Dubois ◽  
...  

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