scholarly journals Regulation of Suppressor of Cytokine Signaling 3 (SOC3) by Growth Hormone in Pro-B Cells

2007 ◽  
Vol 21 (10) ◽  
pp. 2503-2515 ◽  
Author(s):  
Johanna L. Barclay ◽  
Stephen T. Anderson ◽  
Michael J. Waters ◽  
Jon D. Curlewis

Abstract Suppressor of cytokine signaling 3 (SOCS3) is expressed by lymphoid cells and can modulate the sensitivity of these cells to cytokine stimulation through inhibition of Janus kinase (JAK)/signal transducers and activators of transcription (STAT) signaling pathways. This study employed a mouse pro-B cell line expressing the human GH receptor (BaF/3-GHR), to elucidate the signal transduction pathways used by GH to elicit SOCS3 expression. GH treatment of these cells caused a rapid, dose-dependent increase in SOCS3 mRNA expression, which was independent of de novo protein synthesis. As expected, GH treatment increased JAK-dependent STAT5 tyrosine phosphorylation, which bound to the proximal STAT response element (pSRE) on the SOCS3 promoter. This process appeared to involve STAT5b, rather than STAT5a. In addition, GH activation of the SOCS3 promoter required a nearby activator protein (AP) 1/cAMP response element (CRE), which bound cAMP response element binding protein, c-Fos, and c-Jun. Moreover, inhibitors of p38 MAPK and c-Jun N-terminal kinase prevented GH-stimulation of SOCS3 mRNA expression in these cells, suggesting a role for these kinases in SOCS3 transcription. Importantly, GH stimulation increased binding of FOXO3a to the SOCS3 promoter at a site overlapping the AP1/CRE response element, and overexpression of FOXO3a in these cells augmented SOCS3 promoter activation. In addition, we show a direct interaction between FOXO3a and STAT5 in these cells, which may provide a link between STAT5 and the AP1 transcription factors on the SOCS3 promoter. We conclude that regulation of SOCS3 expression by GH in a pro-B cell involves not only the pSRE, but also a transcriptionally active complex involving cAMP response element binding protein/c-Fos/c-Jun and FOXO3a. This study has implications for cytokine regulation of SOCS gene expression in lymphoid cells.

2007 ◽  
Vol 196 (1) ◽  
pp. 89-100 ◽  
Author(s):  
Tracy Xiao Cui ◽  
Roland Kwok ◽  
Jessica Schwartz

GH activates the c-fos promoter by regulating multiple transcription factors. This study adds to our understanding of GH-regulated transcription by demonstrating that GH regulates the c-fos cAMP-response element (CRE) and its binding protein, CREB. Activation of the c-fos promoter by GH is impaired by expression of dominant-negative A-CREB. GH stimulates rapid and transient phosphorylation of CREB at Ser 133 (P-CREB), a critical site for transactivation by CREB, in 3T3-F442A preadipocytes. Mutation of this residue impairs GH-induced c-fos expression, suggesting that phosphorylation of CREB at Ser 133 contributes to GH-induced c-fos activation. The MEK inhibitor UO126 impaired the phosphorylation of CREB and that of C/EBPβ, suggesting that ERKs mediate the phosphorylation of both proteins. UO126, but not the protein kinase A inhibitor H89, blocked GH-induced c-fos mRNA expression. A combination of CREB and C/EBPβ enhanced c-fos promoter activation, and mutation of the CRE impaired the enhancement, as well as GH-stimulated c-fos activation. GH treatment increased the occupancy of both endogenous phospho-CREB and phospho-C/EBPβ on the c-fos promoter. The increases were impaired by UO126. The active P-CREB and P-C/EBPβ are induced by GH to occupy the same c-fos promoter DNA, suggesting that they may participate in a GH-regulated complex on c-fos. These findings suggest that coordinated phosphorylation of CREB and C/EBPβ in response to GH is mediated by ERK1/2, and that the phosphorylated proteins are part of a regulatory complex that occupies c-fos in vivo to regulate c-fos transcription cooperatively in response to GH.


Author(s):  
Ayman E El-Sahar ◽  
Nesma A Shiha ◽  
Nesrine S El Sayed ◽  
Lamiaa A Ahmed

Abstract Background Endotoxin-induced neuroinflammation plays a crucial role in the pathogenesis and progression of various neurodegenerative diseases. A growing body of evidence supports that incretin-acting drugs possess various neuroprotective effects that can improve learning and memory impairments in Alzheimer’s disease models. Thus, the present study aimed to investigate whether alogliptin, a dipeptidyl peptidase-4 inhibitor, has neuroprotective effects against lipopolysaccharide (LPS)-induced neuroinflammation and cognitive impairment in mice as well as the potential mechanisms underlying these effects. Methods Mice were treated with alogliptin (20 mg/kg/d; p.o.) for 14 days, starting 1 day prior to intracerebroventricular LPS injection (8 μg/μL in 3 μL). Results Alogliptin treatment alleviated LPS-induced cognitive impairment as assessed by Morris water maze and novel object recognition tests. Moreover, alogliptin reversed LPS-induced increases in toll-like receptor 4 and myeloid differentiation primary response 88 protein expression, nuclear factor-κB p65 content, and microRNA-155 gene expression. It also rescued LPS-induced decreases in suppressor of cytokine signaling gene expression, cyclic adenosine monophosphate (cAMP) content, and phosphorylated cAMP response element binding protein expression in the brain. Conclusion The present study sheds light on the potential neuroprotective effects of alogliptin against intracerebroventricular LPS-induced neuroinflammation and its associated memory impairment via inhibition of toll-like receptor 4/ myeloid differentiation primary response 88/ nuclear factor-κB signaling, modulation of microRNA-155/suppressor of cytokine signaling-1 expression, and enhancement of cAMP/phosphorylated cAMP response element binding protein signaling.


2018 ◽  
Vol 15 (10) ◽  
pp. 894-904 ◽  
Author(s):  
Sudipta Chakrabarti ◽  
Malabendu Jana ◽  
Avik Roy ◽  
Kalipada Pahan

Background: Neuroinflammation plays an important role in the pathogenesis of various neurodegenerative diseases including Alzheimer’s disease (AD). Suppressor of cytokine signaling 3 (SOCS3) is an anti-inflammatory molecule that suppresses cytokine signaling and inflammatory gene expression in different cells including microglia. Objective: The pathways through which SOCS3 could be upregulated are poorly described. Cinnamic acid is a metabolite of cinnamon, a natural compound that is being widely used all over the world as a spice or flavoring agent. Here, we examined if cinnamic acid could upregulate SOCS3 in microglia. Method: Microglia and astroglia isolated from mouse brain as well as BV-2 microglial cells were treated with cinnamic acid followed by monitoring the level of SOCS3 and different proinflammatory molecules by RT-PCR and real-time PCR. To nail down the mechanism, we also performed ChIP analysis to monitore the recruitment of cAMP response element binding (CREB) to the socs3 gene promoter and carried out siRNA knockdown of CREB. Results: Cinnamic acid upregulated the expression of SOCS3 mRNA and protein in mouse BV-2 microglial cells in dose- and time-dependent manner. Accordingly, cinnamic acid also increased the level of SOCS3 and suppressed the expression of inducible nitric oxide synthase and proinflammatory cytokines (TNFα, IL-1β and IL-6) in LPSstimulated BV-2 microglial cells. Similar to BV-2 microglial cells, cinnamic acid also increased the expression of SOCS3 in primary mouse microglia and astrocytes. We have seen that cAMP response element is present in the promoter of socs3 gene, that cinnamic acid induces the activation of CREB, that siRNA knockdown of CREB abrogates cinnamic acid-mediated upregulation of SOCS3, and that cinnamic acid treatment leads to the recruitment of CREB to the socs3 gene. Conclusions: These studies suggest that cinnamic acid upregulates the expression of SOCS3 in glial cells via CREB pathway, which may be of importance in neuroinflammatory and neurodegenerative disorders.


2019 ◽  
Vol 17 (3) ◽  
pp. 249-253
Author(s):  
Liu Chenglong ◽  
Liu Haihua ◽  
Zhang Fei ◽  
Zheng Jie ◽  
Wei Fang

Cancer-induced bone pain is a severe and complex pain caused by metastases to bone in cancer patients. The aim of this study was to investigate the analgesic effect of scutellarin on cancer-induced bone pain in rat models by intrathecal injection of Walker 256 carcinoma cells. Mechanical allodynia was determined by paw withdrawal threshold in response to mechanical stimulus, and thermal hyperalgesia was indicated by paw withdrawal latency in response to noxious thermal stimulus. The paw withdrawal threshold and paw withdrawal latencies were significantly decreased after inoculation of tumor cells, whereas administration of scutellarin significantly attenuated tumor cell inoculation-induced mechanical and heat hyperalgesia. Tumor cell inoculation-induced tumor growth was also significantly abrogated by scutellarin. Ca2+/calmodulin-dependent protein kinase II is a multifunctional kinase with up-regulated activity in bone pain models. The activation of Ca2+/calmodulin-dependent protein kinase II triggers phosphorylation of cAMP-response element binding protein. Scutellarin significantly reduced the expression of phosphorylated-Ca2+/calmodulin-dependent protein kinase II and phosphorylated-cAMP-response element binding protein in cancer-induced bone pain rats. Collectively, our study demonstrated that scutellarin attenuated tumor cell inoculation-induced bone pain by down-regulating the expression of phosphorylated-Ca2+/calmodulin-dependent protein kinase II and phosphorylated-cAMP-response element binding protein. The suppressive effect of scutellarin on phosphorylated-Ca2+/calmodulin-dependent protein kinase II/phosphorylated-cAMP-response element binding protein activation may serve as a novel therapeutic strategy for CIBP management.


Circulation ◽  
1995 ◽  
Vol 92 (8) ◽  
pp. 2041-2043 ◽  
Author(s):  
Frank Ulrich Müller ◽  
Peter Bokník ◽  
Andreas Horst ◽  
Jörg Knapp ◽  
Bettina Linck ◽  
...  

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