scholarly journals Krüppel-like factor 3 (KLF3) suppresses NF-κB–driven inflammation in mice

2020 ◽  
Vol 295 (18) ◽  
pp. 6080-6091 ◽  
Author(s):  
Alexander J. Knights ◽  
Lu Yang ◽  
Manan Shah ◽  
Laura J. Norton ◽  
Gamran S. Green ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Cytokine Signaling ◽  
Suppressor Of Cytokine Signaling ◽  
Inflammatory Signals ◽  
Health Burden ◽  
Feedback Inhibitor ◽  
Key Drivers ◽  
Deficient Mice

Bacterial products such as lipopolysaccharides (or endotoxin) cause systemic inflammation, resulting in a substantial global health burden. The onset, progression, and resolution of the inflammatory response to endotoxin are usually tightly controlled to avoid chronic inflammation. Members of the NF-κB family of transcription factors are key drivers of inflammation that activate sets of genes in response to inflammatory signals. Such responses are typically short-lived and can be suppressed by proteins that act post-translationally, such as the SOCS (suppressor of cytokine signaling) family. Less is known about direct transcriptional regulation of these responses, however. Here, using a combination of in vitro approaches and in vivo animal models, we show that endotoxin treatment induced expression of the well-characterized transcriptional repressor Krüppel-like factor 3 (KLF3), which, in turn, directly repressed the expression of the NF-κB family member RELA/p65. We also observed that KLF3-deficient mice were hypersensitive to endotoxin and exhibited elevated levels of circulating Ly6C+ monocytes and macrophage-derived inflammatory cytokines. These findings reveal that KLF3 is a fundamental suppressor that operates as a feedback inhibitor of RELA/p65 and may be important in facilitating the resolution of inflammation.

Prolactin and the expression of suppressor of cytokine signaling-3 in the sheep adrenal gland before birth

2006 ◽  
Vol 291 (5) ◽  
pp. R1399-R1405 ◽  
Author(s):  
S. Gentili ◽  
J. S. Schwartz ◽  
M. J. Waters ◽  
I. C. McMillen
Keyword(s):  
Adrenal Gland ◽  
Mrna Expression ◽  
Tissue Growth ◽  
Late Gestation ◽  
Cytokine Signaling ◽  
Suppressor Of Cytokine Signaling ◽  
Subsequent Increase ◽  
Fetal Sheep

The fetal pituitary-adrenal axis plays a key role in the fetal response to intrauterine stress and in the timing of parturition. The fetal sheep adrenal gland is relatively refractory to stimulation in midgestation (90–120 days) before the prepartum activation, which occurs around 135 days gestation (term = 147 ± 3 days). The mechanisms underlying the switch from adrenal quiescence to activation are unclear. Therefore, we have investigated the expression of suppressor of cytokine signaling-3 (SOCS-3), a putative inhibitor of tissue growth in the fetal sheep adrenal between 50 and 145 days gestation and in the adrenal of the growth-restricted fetal sheep in late gestation. SOCS-3 is activated by a range of cytokines, including prolactin (PRL), and we have, therefore, determined whether PRL administered in vivo or in vitro stimulates SOCS-3 mRNA expression in the fetal adrenal in late gestation. There was a decrease ( P < 0.005) in SOCS-3 expression in the fetal adrenal between 54 and 133 days and between 141 and 144 days gestation. Infusion of the dopaminergic agonist, bromocriptine, which suppressed fetal PRL concentrations but did not decrease adrenal SOCS-3 mRNA expression. PRL administration, however, significantly increased adrenal SOCS-3 mRNA expression ( P < 0.05). Similarly, there was an increase ( P < 0.05) in SOCS-3 mRNA expression in adrenocortical cells in vitro after exposure to PRL (50 ng/ml). Placental and fetal growth restriction had no effect on SOCS-3 expression in the adrenal during late gestation. In summary, the decrease in the expression of the inhibitor SOCS-3 after 133 days gestation may be permissive for a subsequent increase in fetal adrenal growth before birth. We conclude that factors other than PRL act to maintain adrenal SOCS-3 mRNA expression before 133 days gestation but that acute elevations of PRL can act to upregulate adrenal SOCS-3 expression in the sheep fetus during late gestation.

scholarly journals miR-155 accelerates proliferation of mouse hepatocytes during liver regeneration by directly targeting SOCS1

2018 ◽  
Vol 315 (4) ◽  
pp. G443-G453 ◽  
Author(s):  
Xia Lin ◽  
Li Chen ◽  
Haiyan Li ◽  
Yu Liu ◽  
Yanhong Guan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Liver Regeneration ◽  
Partial Hepatectomy ◽  
Molecular Mechanisms ◽  
Pharmacological Intervention ◽  
Cytokine Signaling ◽  
Suppressor Of Cytokine Signaling ◽  
Proliferation Of Hepatocytes

Liver regeneration after two-thirds partial hepatectomy (PH) is a clinically significant repair process for restoring proper liver architecture. Although microRNA-155 (miR-155) has been found to serve as a crucial microRNA regulator that controls liver cell function and proliferation, little is known about its specific role in the regenerating liver. Using a mouse model with miR-155 overexpression or miR-155 knockout, we investigated the molecular mechanisms of miR-155 in liver regeneration. We found a marked induction of miR-155 in C57BL/6 mice after PH. Furthermore, RL-m155 mice showed enhanced liver regeneration as a result of accelerated progression of hepatocytes into the cell cycle, mainly through an increase in cyclin levels. However, proliferation of hepatocytes was delayed in miR-155-deficient livers. Expression of suppressor of cytokine signaling 1 (SOCS1) was dramatically downregulated in the process of liver regeneration, and enhancement of SOCS1 contributed to impaired proliferation of hepatocytes. Additionally, in vitro and in vivo experiments showed that adenovirus- or adeno-associated virus-mediated overexpression of SOCS1 attenuated improved liver regeneration induced by miR-155 overexpression. Our study shows that miR-155 is a pro-proliferative regulator in liver regeneration by facilitating the cell cycle and directly targeting SOCS1. NEW & NOTEWORTHY Our findings suggest a microRNA-155 (miR-155)-mediated positive regulation pattern in liver regeneration. A series of in vivo and in vitro studies showed that miR-155 upregulation enhanced partial hepatectomy-induced proliferation of hepatocytes by promoting the cell cycle without inducing DNA damage or apoptosis. Suppressor of cytokine signaling 1, a target gene of miR-155, antagonized the proliferation-promoting effect of miR-155. Therefore, pharmacological intervention targeting miR-155 may be therapeutically beneficial in various liver diseases.

scholarly journals Unique Expression of Suppressor of Cytokine Signaling 3 Is Essential for Classical Macrophage Activation in Rodents In Vitro and In Vivo

2008 ◽  
Vol 180 (9) ◽  
pp. 6270-6278 ◽  
Author(s):  
Yu Liu ◽  
Keith N. Stewart ◽  
Eileen Bishop ◽  
Carylyn J. Marek ◽  
David C. Kluth ◽  
...  
Keyword(s):  
Macrophage Activation ◽  
Cytokine Signaling ◽  
Suppressor Of Cytokine Signaling

scholarly journals MiR-142-3p Suppresses SOCS6 Expression and Promotes Cell Proliferation in Nasopharyngeal Carcinoma

2015 ◽  
Vol 36 (5) ◽  
pp. 1743-1752 ◽  
Author(s):  
Xiaoming Qi ◽  
Jianqiang Li ◽  
Changbo Zhou ◽  
Chunlei Lv ◽  
Min Tian
Keyword(s):  
Cell Proliferation ◽  
Nasopharyngeal Carcinoma ◽  
Cell Cycle Progression ◽  
Therapeutic Strategy ◽  
Cytokine Signaling ◽  
Suppressor Of Cytokine Signaling ◽  
Cycle Progression ◽  
Direct Target

Background/Aims: An increasing number of studies show that microRNAs (miRNAs) play crucial roles in nasopharyngeal carcinoma (NPC) tumorigenesis. The aim of our study was to investigate the biological roles and mechanisms of miR-142-3p in NPC. Methods: miR-142-3p expression was examined in NPC specimens and nasopharyngitis biopsy samples by quantitative real-time PCR. The biological functions of miR-142-3p were studied using a series of in vitro and in vivo approaches. Results: miR-142-3p is over-expressed in NPC tissues and cell lines. Knockdown of miR-142-3p significantly inhibited cell proliferation and cell cycle progression in vitro, and suppressed tumor growth in a mouse model. Suppressor of cytokine signaling 6 (SOCS6) was identified as a direct target of miR-142-3p, and miR-142-3p down-regulated the expression of SOCS6 by directly binding to its 3′untranslated region (UTR). Knockdown of SOCS6 abrogated the effects of miR-142-3p down-regulation. Conclusion: These findings indicate that miR-142-3p regulates NPC development by down-regulating SOCS6 expression and suggest that modulation of miR-142-3p expression could be a therapeutic strategy for NPC.

PIAS proteins promote SUMO-1 conjugation to STAT1

Blood ◽  
2003 ◽  
Vol 102 (9) ◽  
pp. 3311-3313 ◽  
Author(s):  
Daniela Ungureanu ◽  
Sari Vanhatupa ◽  
Noora Kotaja ◽  
Jie Yang ◽  
Saara Aittomäki ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Posttranslational Modifications ◽  
Interferon Γ ◽  
Regulatory Function ◽  
Cytokine Signaling ◽  
Signal Transducer ◽  
Protein Inhibitor ◽  
Ifn Γ

AbstractSignal transducer and activator of transcription 1 (STAT1) is a critical mediator of interferon-γ (IFN-γ)–induced transcription that is regulated through posttranslational modifications and through transacting proteins such as protein inhibitor of activated STAT1 (PIAS1). PIAS proteins have been shown to function as E3-type small ubiquitin-like modifier (SUMO) ligases, and sumoylation has been identified as a modulatory mechanism for several transcription factors. Here we show that STAT1 is subject to SUMO-1 modification, and sumoylation occurs in vivo and in vitro at a single, evolutionary conserved amino acid residue Lys703. Members of the PIAS family of proteins were found to strongly stimulate sumoylation of STAT1. Furthermore, activation of STAT1 by IFN-γ or pervanadate induced SUMO-1 conjugation. Mutation of Lys703 in STAT1 resulted in increased IFN-γ–mediated transactivation, suggesting a negative regulatory function for sumoylation. These results indicate that STAT1 is covalently modified by SUMO-1 in cytokine signaling and that PIAS proteins promote SUMO-1 conjugation to STAT1.

scholarly journals Inflammatory signals directly instruct PU.1 in HSCs via TNF

Blood ◽  
2019 ◽  
Vol 133 (8) ◽  
pp. 816-819 ◽  
Author(s):  
Martin Etzrodt ◽  
Nouraiz Ahmed ◽  
Philipp S. Hoppe ◽  
Dirk Loeffler ◽  
Stavroula Skylaki ◽  
...  
Keyword(s):  
Tumor Necrosis ◽  
Molecular Mechanisms ◽  
Myeloid Differentiation ◽  
Cytokine Signaling ◽  
Hematopoietic Stem ◽  
Inflammatory Signals ◽  
Necrosis Factor ◽  
Direct Regulation

Abstract The molecular mechanisms governing the transition from hematopoietic stem cells (HSCs) to lineage-committed progenitors remain poorly understood. Transcription factors (TFs) are powerful cell intrinsic regulators of differentiation and lineage commitment, while cytokine signaling has been shown to instruct the fate of progenitor cells. However, the direct regulation of differentiation-inducing hematopoietic TFs by cell extrinsic signals remains surprisingly difficult to establish. PU.1 is a master regulator of hematopoiesis and promotes myeloid differentiation. Here we report that tumor necrosis factor (TNF) can directly and rapidly upregulate PU.1 protein in HSCs in vitro and in vivo. We demonstrate that in vivo, niche-derived TNF is the principal PU.1 inducing signal in HSCs and is both sufficient and required to relay signals from inflammatory challenges to HSCs.

scholarly journals IL-33 Attenuates Sepsis by Inhibiting IL-17 Receptor Signaling through Upregulation of SOCS3

2017 ◽  
Vol 42 (5) ◽  
pp. 1961-1972 ◽  
Author(s):  
Ran Lv ◽  
Jinning Zhao ◽  
Min Lei ◽  
Dongju Xiao ◽  
Yijin Yu ◽  
...  
Keyword(s):  
Cecal Ligation ◽  
Serum Levels ◽  
Cytokine Signaling ◽  
Experimental Sepsis ◽  
Suppressor Of Cytokine Signaling ◽  
Γδt Cells ◽  
Negative Regulatory Role

Background/Aims: Sepsis is a systemic inflammatory response during infection. There are limited therapeutic options for sepsis patients. Interleukin (IL)-33 has been reported recently with a beneficial effect in mouse sepsis. Methods: In this study, we initiated a clinical study to measure serum levels of pro-inflammatory cytokines including IL-33 in sepsis patients. Next, we employed cecal ligation and puncture (CLP) to study the role of IL-33 during sepsis. To further dissect the molecular mechanism, we used in vivo knockout models and in vitro knockdown murine embryonic fibroblasts (MEFs) to investigate the cross-talk between IL-33 and IL-17 signaling, and to identify the potential downstream mediators. Results: IL-33 and IL-17 were upregulated in both clinical and experimental sepsis. In CLP, IL-33 (-/-) mice showed higher mortality rate, and IL-33 treatment improved the survival rate. Elevated proinflammatory cytokines in sepsis were related to IL-17 from γδT cells. IL-33 treatment suppressed production of these cytokines by targeting IL-17 signaling both in vivo and in vitro. Finally, IL-33 was shown to inhibit the IL-17 pathway via activating suppressor of cytokine signaling (SOCS)-3. Conclusion: Collectively, the results suggest that IL-33 plays a negative regulatory role in sepsis progression by inhibiting IL-17 pathway through activating SOCS3. This finding would inspire a new therapeutic strategy for treating sepsis.

scholarly journals SOCS3 is an endogenous inhibitor of pathologic angiogenesis

Blood ◽  
2012 ◽  
Vol 120 (14) ◽  
pp. 2925-2929 ◽  
Author(s):  
Andreas Stahl ◽  
Jean-Sebastian Joyal ◽  
Jing Chen ◽  
Przemyslaw Sapieha ◽  
Aimee M. Juan ◽  
...  
Keyword(s):  
Growth Factor ◽  
Feedback Inhibition ◽  
Cytokine Signaling ◽  
Growth Factor Signaling ◽  
Suppressor Of Cytokine Signaling ◽  
Oxygen Induced Retinopathy ◽  
Vessel Growth ◽  
Feedback Inhibitor ◽  
Feedback Regulator

Abstract Inflammatory cytokines and growth factors drive angiogenesis independently; however, their integrated role in pathologic and physiologic angiogenesis is not fully understood. Suppressor of cytokine signaling-3 (SOCS3) is an inducible negative feedback regulator of inflammation and growth factor signaling. In the present study, we show that SOCS3 curbs pathologic angiogenesis. Using a Cre/Lox system, we deleted SOCS3 in vessels and studied developmental and pathologic angiogenesis in murine models of oxygen-induced retinopathy and cancer. Conditional loss of SOCS3 leads to increased pathologic neovascularization, resulting in pronounced retinopathy and increased tumor size. In contrast, physiologic vascularization is not regulated by SOCS3. In vitro, SOCS3 knockdown increases proliferation and sprouting of endothelial cells costimulated with IGF-1 and TNFα via reduced feedback inhibition of the STAT3 and mTOR pathways. These results identify SOCS3 as a pivotal endogenous feedback inhibitor of pathologic angiogenesis and a potential therapeutic target acting at the converging crossroads of growth factor– and cytokine-induced vessel growth.

scholarly journals Selective Immunomodulation of Inflammatory Pathways in Keratinocytes by the Janus Kinase (JAK) Inhibitor Tofacitinib: Implications for the Employment of JAK-Targeting Drugs in Psoriasis

2018 ◽  
Vol 2018 ◽  
pp. 1-18 ◽  
Author(s):  
Martina Morelli ◽  
Claudia Scarponi ◽  
Laura Mercurio ◽  
Francesco Facchiano ◽  
Sabatino Pallotta ◽  
...  
Keyword(s):  
Skin Lesions ◽  
Janus Kinase ◽  
Psoriatic Skin ◽  
Epidermal Keratinocytes ◽  
Cytokine Signaling ◽  
Molecular Signaling ◽  
Suppressor Of Cytokine Signaling ◽  
Inflammatory Genes

IFN-γ and IL-22 are deeply involved in the pathogenesis of psoriasis, as they boost the expression of inflammatory genes and alter proliferative and differentiative programs in keratinocytes. The JAK1/JAK2/STAT1 and JAK1/TYK2/STAT3 pathways triggered by IFN-γ and IL-22, respectively, are aberrantly activated in psoriasis, as highlighted by the peculiar STAT1 and STAT3 signatures in psoriatic skin lesions. To limit the detrimental consequences of IFN-γ and IL-22 excessive stimulation, psoriatic keratinocytes activate suppressor of cytokine signaling (SOCS)1 and SOCS3, which in turn dampen molecular signaling by inhibiting JAK1 and JAK2. Thus, JAK targeting appears to be a reasonable strategy to treat psoriasis. Tofacitinib is an inhibitor of JAK proteins, which, similarly to SOCS, impedes JAK phosphorylation. In this study, we evaluated the immunomodulatory effects of tofacitinib on epidermal keratinocytes in in vitro and in vivo models of psoriasis. We demonstrated the selectivity of tofacitinib inhibitory action on IFN-γ and IL-22, but not on TNF-γ or IL-17 proinflammatory signaling, with suppressed expression of IFN-γ-dependent inflammatory genes, and restoration of normal proliferative and differentiative programs altered by IL-22 in psoriatic keratinocyte cultures. Tofacitinib also potently reduced the psoriasiform phenotype in the imiquimod-induced murine model of psoriasis. Finally, we found that tofacitinib mimics SOCS1 or SOCS3 activities, as it impaired the same molecular pathways in IFN-γ or IL-22-activated keratinocytes.

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