scholarly journals Transforming Growth Factor-βs Inhibit Somatostatin Messenger Ribonucleic Acid Levels and Somatostatin Secretion in Hypothalamic Cells in Culture*

Endocrinology ◽  
1997 ◽  
Vol 138 (10) ◽  
pp. 4401-4409 ◽  
Author(s):  
M. Quintela ◽  
R. M. SeñarÍs ◽  
C. Diéguez

Abstract Treatment of hypothalamic cells in monolayer culture with transforming growth factor-β1 (TGFβ1) significantly reduced both basal and cAMP-induced somatostatin messenger RNA (mRNA) levels and somatostatin secretion. This inhibitory effect was dose- and time-dependent and not mediated by glial cells, as it was also observed in glial-free hypothalamic cell cultures treated with cytosine arabinonucleoside. TGFβ2 and -β3 mimicked the actions of TGFβ1, which indicated that the three isoforms of the TGFβ family expressed in the central nervous system displayed similar effects on the somatostatinergic neurons. The blockade of synthesis of proteins with either cycloheximide or puromycin for 24 h prevented the inhibitory effect of TGFβ1 on somatostatin mRNA. This implied that the reduction of this mRNA by TGFβ1 required de novo protein synthesis. We next studied whether TGFβ1 acted at the transcriptional or posttranscriptional level by altering the stability of somatostatin mRNA. Examination of the rate of disappearance of somatostatin mRNA by Northern blot, after inhibition of mRNA transcription with either actinomycin D (AcD) or 5,6-dichloro-1β-ribofuranosyl benzimidazole revealed that TGFβ1 did reduce the stability of somatostatin mRNA. This effect was observed when we pretreated the cultures with TGFβ1 4 h before the addition of AcD, but not when we administered TGFβ1 simultaneously with AcD or 5,6-dichloro-1β-ribofuranosyl benzimidazole. Altogether these results demonstrated that the treatment of hypothalamic cells in culture with TGFβ1, TGFβ2, or TGFβ3 resulted in a decrease in somatostatin mRNA levels and somatostatin secretion. TGFβ1 reduced the steady state levels of somatostatin mRNA by inducing the synthesis of a protein (s), that appears to accelerate the degradation of the mRNA of somatostatin. Whether TGFβ1 has additional effects on the transcription of the somatostatin gene will require further study.

2005 ◽  
Vol 186 (1) ◽  
pp. 109-121 ◽  
Author(s):  
M-O Faure ◽  
L Nicol ◽  
S Fabre ◽  
J Fontaine ◽  
N Mohoric ◽  
...  

Activins and inhibins, members of the transforming growth factor-beta family are able to stimulate and inhibit, respectively, FSH synthesis and release. Other members of this superfamily, the bone morphogenetic proteins (BMPs), may also affect FSH synthesis in the mouse. The aim of this work was to determine whether BMPs are expressed in the ovine pituitary and whether they play a role in the regulation of FSH release. The mRNAs encoding BMP-2, BMP-4, BMP-7 and the oocyte-derived growth factor, growth differentiation factor (GDF)-9 were detected in the pituitaries of cyclic ewes by reverse-transcriptase PCR, as well as the mRNAs encoding the BMP type I receptors, BMPR-IA (activin-receptor-like kinase (ALK)-3) and BMPR-IB (ALK-6), and type II receptors (BMPR-II). Immunolabeling of pituitary sections revealed the presence of BMPR-IA (ALK-3) and BMPR-II in gonadotrope cells. To investigate the potential effects of BMPs on FSH secretion, ewe pituitary cell cultures were treated with BMP-4 (10−11 M to 10−9 M) for 48 h. Interestingly, FSH release was decreased in a dose-dependent manner. At 10−9 M BMP-4 both FSH concentration and FSHβ mRNA expression were reduced by 40% of control values. In contrast, there was no inhibitory effect on either LH or LHβ mRNA expression. A similar result was found with BMP-6. BMP-4 triggered the phosphorylation of Smad1, suggesting that the effect of BMP-4 on FSH secretion is due to the activation of the BMPs signaling pathway. Furthermore, BMP-4 blocked the stimulatory effect of activin on both FSH release and FSHβ mRNA and amplified the suppression of FSH release and FSHβ mRNA levels induced by 17β-estradiol. These results indicate that a functional BMP system operates within the sheep pituitary, at least in vitro, to decrease FSH release and to modulate the effect of activin.


2018 ◽  
Vol 27 (2) ◽  
pp. 256-263 ◽  
Author(s):  
Tung-Chou Wen ◽  
Yuan-Sheng Li ◽  
Karthyayani Rajamani ◽  
Horng-Jyh Harn ◽  
Shinn-Zong Lin ◽  
...  

In this study, we explored the effect of the water extract of Cinnamomum osmophloeum Kanehira (COK) leaves on hair growth by in vitro and in vivo assays. Using an in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, it was found that the proliferation of rat vibrissae and human hair dermal papilla cells (hDPCs) was significantly enhanced by the COK leaf extract treatment. As determined by quantitative real-time polymerase chain reaction (RT-PCR), the messenger RNA (mRNA) levels of some hair growth–related factors including vascular endothelial growth factor, keratinocyte growth factor (KGF), and transforming growth factor-β2 were found to be higher in the cultured hDPCs exposed to COK leaf extract than those in the untreated control group. In the hair-depilated C57BL/6 mouse model, the stimulation of hair growth was demonstrated in the group of COK leaf extract treatment. Both photographical and histological observations revealed the promotion of the anagen phase in the hair growth cycle by the COK leaf extract in the C57BL/6 mice. Finally, the ultra performance liquid chromatography (UPLC) showed that the COK extract contained mostly cinnamic aldehyde and a small amount of cinnamic acid. The results suggest that the COK leaf extract may find use for the treatment of hair loss.


2002 ◽  
Vol 9 (4) ◽  
pp. 802-807 ◽  
Author(s):  
Patricia Méndez-Samperio ◽  
Elizabeth García ◽  
Abraham Vázquez ◽  
Janet Palma

ABSTRACT Recent studies indicate that interleukin 8 (IL-8) production contributes to the host immune responses against mycobacterial infection. In this study, we were interested to determine whether induction of IL-8 in human monocytes infected with Mycobacterium bovis was regulated by other monocyte-derived cytokines important in antimycobacterial immunity: IL-10 and transforming growth factor β (TGF-β). Here, we report that IL-10 reduced, in a graded and significant manner, IL-8 production by M. bovis-infected human monocytes. Additionally, the specificity of the observed inhibition was further confirmed, since the addition of an anti-IL-10 neutralizing antibody completely reversed the inhibitory effect. In contrast, addition or neutralization of TGF-β appeared to have no significant effect on M. bovis-induced IL-8 secretion by human monocytes, whereas CD40 expression on M. bovis-infected monocytes was significantly inhibited by this cytokine. This was consistent with the finding by the reverse transcription-PCR method that pretreatment with IL-10, but not TGF-β, potently inhibited IL-8 mRNA levels. Interestingly, neutralization of endogenous IL-10 did not significantly alter IL-8 secretion, suggesting that induction of IL-8 was not significantly affected by coexpression of IL-10 during infection of human monocytes with M. bovis. Collectively, these data indicate that IL-8 production may be regulated when human monocytes are exposed to IL-10 prior to activation with M. bovis BCG. These data will aid in our understanding of the mechanisms involved in regulating the protective immune response to stimulation with M. bovis BCG.


Endocrinology ◽  
1997 ◽  
Vol 138 (3) ◽  
pp. 1224-1231 ◽  
Author(s):  
Ursula B. Kaiser ◽  
Andrzej Jakubowiak ◽  
Anna Steinberger ◽  
William W. Chin

Abstract The hypothalamic hormone, GnRH, is released and transported to the anterior pituitary in a pulsatile manner, where it binds to specific high-affinity receptors and regulates gonadotropin biosynthesis and secretion. The frequency of GnRH pulses changes under various physiological conditions, and varying GnRH pulse frequencies have been shown to regulate differentially the secretion of LH and FSH and the expression of the gonadotropin α, LHβ, and FSHβ subunit genes in vivo. We demonstrate differential effects of varying GnRH pulse frequency in vitro in superfused primary monolayer cultures of rat pituitary cells. Cells were treated with 10 nm GnRH pulses for 24 h at a frequency of every 0.5, 1, 2, or 4 h. α, LHβ, and FSHβ messenger RNA (mRNA) levels were increased by GnRH at all pulse frequencies. α and LHβ mRNA levels and LH secretion were stimulated to the greatest extent at a GnRH pulse frequency of every 30 min, whereas FSHβ mRNA levels and FSH secretion were stimulated maximally at a lower GnRH pulse frequency, every 2 h. GnRH receptor (GnRHR) mRNA levels also were increased by GnRH at all pulse frequencies and were stimulated maximally at a GnRH pulse frequency of every 30 min. Similar results were obtained when the dose of each pulse of GnRH was adjusted to maintain a constant total cumulative dose of GnRH over 24 h. These data show that gonadotropin subunit gene expression is regulated differentially by varying GnRH pulse frequencies in vitro, suggesting that the differential effects of varying GnRH pulse frequencies on gonadotropin subunit gene expression occur directly at the level of the pituitary. The pattern of regulation of GnRHR mRNA levels correlated with that of α and LHβ but was different from that of FSHβ. This suggests that α and LHβ mRNA levels are maximally stimulated when GnRHR levels are relatively high, whereas FSHβ mRNA levels are maximally stimulated at lower levels of GnRHR expression, and that the mechanism for differential regulation of the gonadotropins by varying pulse frequencies of GnRH may involve levels of GnRHR. Furthermore, these data suggest that the mechanisms whereby varying GnRH pulse frequencies stimulate α, LHβ, and GnRHR gene expression are similar, whereas the stimulation of FSHβ mRNA levels may be different.


2007 ◽  
Vol 67 (4) ◽  
pp. 559-562 ◽  
Author(s):  
K Warstat ◽  
T Pap ◽  
G Klein ◽  
S Gay ◽  
W K Aicher

We showed previously that the attachment of synovial fibroblasts to laminin (LM)-111 in the presence of transforming growth factor-β induces significant expression of the matrix metalloproteinase (MMP)-3. Here we go on to investigate the regulation of additional MMPs and their specific tissue inhibitors of matrix proteases (TIMPs). Changes in steady-state mRNA levels encoding TIMPs and MMPs were investigated by quantitative reverse transcription–polymerase chain reaction. Production of MMPs was monitored by a multiplexed immunoarray. Signal transduction pathways were studied by immunoblotting. Attachment of synovial fibroblasts to LM-111 in the presence of transforming growth factor-β induced significant increases in MMP-3 mRNA (12.35-fold, p<0.001) and protein (mean 62 ng/ml, sixfold, p<0.008) and in expression of MMP-10 mRNA (11.68-fold, p<0.05) and protein (54 ng/ml, 20-fold, p⩾0.02). All other TIMPs and MMPs investigated failed to show this LM-111-facilitated transforming growth factor-β response. No phosphorylation of nuclear factor-κB was observed. We conclude that co-stimulation of synovial fibroblasts by LM-111 together with transforming growth factor-β suffices to induce significant expression of MMP-3 and MMP-10 by synovial fibroblasts and that this induction is independent of nuclear factor-κB phosphorylation.


2002 ◽  
Vol 195 (11) ◽  
pp. 1499-1505 ◽  
Author(s):  
Leonid Gorelik ◽  
Stephanie Constant ◽  
Richard A. Flavell

Regulation by transforming growth factor (TGF)-β plays an important role in immune homeostasis. TGF-β inhibits T cell functions by blocking both proliferation and differentiation. Here we show that TGF-β blocks Th1 differentiation by inhibiting the expression of T-bet, the apparent masterregulator of T helper (Th)1 differentiation. Restoration of T-bet expression through retroviral transduction of T-bet into developing Th1 cells abrogated the inhibitory effect of TGF-β. In addition, we show that, contrary to prior suggestions, downregulation of interleukin 12 receptor β2 chain is not key to the TGF-β–mediated effect. Furthermore, we show that the direct inhibitory effect of TGF-β on T cells is responsible, at least in part, for the inability of BALB/c mice to mount a Leishmania-specific Th1 response and to clear Leishmanial infection.


1998 ◽  
Vol 83 (2) ◽  
pp. 448-452
Author(s):  
H. F. Erden ◽  
I. H. Zwain ◽  
H. Asakura ◽  
S. S. C. Yen

Recently, we reported that the thecal compartment of the human ovary contains a CRF system replete with gene expression and protein for corticotropin-releasing factor (CRF), CRF-Receptor 1 (CRF-R1), and the blood-derived high affinity CRF-binding protein (CRF-BP). Granulosa cells are devoid of the CRF system. The parallel increases in intensity of CRF, CRF-R1, and 17α-hydroxylase messenger ribonucleic acid (mRNA) and proteins in thecal cells with follicular maturation suggest that the intraovarian CRF system may play an autocrine role regulating androgen biosynthesis, with a downstream effect on estrogen production by granulosa cells. The functionality of the ovarian CRF system may be conditioned by the relative presence of plasma-derived CRF-BP by virtue of its localization of protein, but not transcript in thecal cells and its ability to compete with CRF for the CRF receptor. To further these findings, in the present study we have examined the effect of CRF on LH-stimulated 17α-hydroxylase (P450c17) gene expression and androgen production by isolated thecal cells from human ovarian follicles (11–13 mm). During the 48-h culture, addition of LH (10 ng/mL) to the medium increased by 5- and 6-fold dehydroepiandrosterone and androstenedione production by thecal cells. Remarkably, the LH-stimulated, but not basal, androgen production was inhibited by CRF in a time- and dose-dependent manner. The half-maximal (ID50) effect dose of CRF occurred at 5 × 10−8 mol/L, and at a maximal concentration of 10−6 mol/L, CRF completely inhibited LH-stimulated androgen production. This inhibitory effect of CRF became evident at 12 h (45%), and by 24 h the effect was more pronounced, with a 70% reduction from baseline. As determined by Northern analyses, CRF dose dependently decreased LH-stimulated P450c17 mRNA levels, with a maximal inhibition of 85% P450c17 gene expression at a CRF concentration of 10−6 mol/L. With the addition of 10−6 mol/L of the antagonist α-helical CRF-(9–41), the inhibitory effect of CRF was partially reversed for both P450c17 mRNA (75%) and androgen production (50%), indicating the CRF-R1-mediated event. In conclusion, the present study demonstrated a potent inhibitory effect of CRF on LH-stimulated dehydroepiandrosterone and androstenedione production that appears to be mediated through the reduction of P450c17 gene expression. Thus, the ovarian CRF system may function as autocrine regulators for androgen biosynthesis in the thecal cell compartment to maintain optimal substrate for estrogen biosynthesis by granulosa cells. Further studies to define the role of CRF-BP in the endocrine modulation of the intraovarian CRF system are needed.


2015 ◽  
Vol 130 (1) ◽  
pp. 89-94 ◽  
Author(s):  
R Sun ◽  
X-Y Tang ◽  
Y Yang

AbstractObjectives:To determine the role of regulatory T/type 2 helper cell-mediated immune imbalance in the pathogenesis of allergic rhinitis and examine the association between clinical severity and regulatory T/type 2 helper cell-mediated immune imbalance.Methods:Levels of interleukins 4 and 5 and transforming growth factor β1, and expression of FOXP3 and GATA3 (which are functionally related to regulatory T and type 2 helper cells, respectively), were evaluated in 46 allergic rhinitis patients and 42 healthy subjects.Results:Compared to controls, allergic rhinitis patients showed significantly higher interleukin 4 and 5 levels, but lower transforming growth factor β1 levels. Furthermore, FOXP3 messenger RNA expression was lower in allergic rhinitis patients, while GATA3 messenger RNA and protein expression was significantly higher. Regulatory T/type 2 helper cell ratio was inversely correlated with clinical symptom scores.Conclusion:Regulatory T/type 2 helper cell immune imbalance may contribute to allergic rhinitis development. These findings provide a new insight into disease pathogenesis and potential therapeutic approaches.


2000 ◽  
Vol 279 (3) ◽  
pp. R786-R792 ◽  
Author(s):  
Takeshi Kubota ◽  
Jidong Fang ◽  
Tetsuya Kushikata ◽  
James M. Krueger

Proinflammatory cytokines, including interleukin-1β and tumor necrosis factor-α are involved in physiological sleep regulation. Interleukin (IL)-13 and transforming growth factor (TGF)-β1 are anti-inflammatory cytokines that inhibit proinflammatory cytokines by several mechanisms. Therefore, we hypothesized that IL-13 and TGF-β1 could attenuate sleep in rabbits. Three doses of IL-13 (8, 40, and 200 ng) and TGF-β1 (40, 100, and 200 ng) were injected intracerebroventricularly 3 h after the beginning of the light period. In addition, one dose of IL-13 (200 ng) and one dose of TGF-β1 (200 ng) were injected at dark onset. The two higher doses of IL-13 and the highest dose of TGF-β1 significantly inhibited spontanenous non-rapid eye movement sleep (NREMS) when they were given in the light period. IL-13 also inhibited NREMS after dark onset administration; however, the inhibitory effect was less potent than that observed after light period administration. The 40-ng dose of IL-13 inhibited REMS duration during the dark period. TGF-β1 administered at dark onset had no effect on sleep. These data provide additional evidence for the hypothesis that a brain cytokine network is involved in regulation of physiological sleep.


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