Galantamine mitigates testicular injury and disturbed spermatogenesis in adjuvant arthritic rats via modulating apoptosis, inflammatory signals, and IL-6/JAK/STAT3/SOCS3 signaling

Rheumatoid arthritis (RA) affects the joints and the endocrine system via persistent immune system activation. RA patients have a higher frequency of testicular dysfunction, impotence, and decreased libido. This investigation aimed to evaluate the efficacy of galantamine (GAL) on testicular injury secondary to RA. Rats were allocated into four groups: control, GAL (2 mg/kg/day, p.o), CFA (0.3 mg/kg, s.c), and CFA + GAL. Testicular injury indicators, such as testosterone level, sperm count, and gonadosomatic index, were evaluated. Inflammatory indicators, such as interleukin-6 (IL-6), p-Nuclear factor kappa B (NF-κB p65), and anti-inflammatory cytokine interleukin-10 (IL-10), were assessed. Cleaved caspase-3 expression was immunohistochemically investigated. Protein expressions of Janus kinase (JAK), signal transducers and activators of transcription (STAT3), and Suppressors of Cytokine Signaling 3 (SOCS3) were examined by Western blot analysis. Results show that serum testosterone, sperm count, and gonadosomatic index were increased significantly by GAL. Additionally, GAL significantly diminished testicular IL-6 while improved IL-10 expression relative to CFA group. Furthermore, GAL attenuated testicular histopathological abnormalities by CFA and downregulated cleaved caspase-3 and NF-κB p65 expressions. It also downregulated JAK/STAT3 cascade with SOCS3 upregulation. In conclusion, GAL has potential protective effects on testicular damage secondary to RA via counteracting testicular inflammation, apoptosis, and inhibiting IL-6/JAK/STAT3/SOCS3 signaling.

M2 Macrophage-Derived Extracellular Vesicles Containing MicroRNA-501-3p Promote Colon Cancer Progression Through the SETD7/DNMT1/SOCS3 Axis

BACKGROUND

Macrophage-derived extracellular vesicles with microRNAs can cause and develop colon cancer.

OBJECTIVE

To investigate M2 macrophage-derived extracellular vesicles and colon cancer.

DESIGN

A prospective and experimental study of M2 macrophage-derived extracellular vesicles in colon cancer.

SETTING

This study was completed at the Fourth Hospital of Hebei Medical University.

PATIENTS

Patients with colon cancer who had undergone surgical resection.

MAIN OUTCOME MEASURES

Suppressor of cytokine signaling 3, miR-501-3p, SET domain containing 7, and DNA methyltransferase 1 were measured in colon cancer samples. Multiple experiments determined suppressor of cytokine signaling 3, miR-501-3p, SET domain containing 7, and DNA methyltransferase 1 binding affinity. M2 macrophages were cultivated from M0 macrophages isolated from peripheral blood mononuclear cells of a healthy donor and polarized to produce extracellular vesicles. Gain- or loss-of-function tests using colon cancer cells and M2 macrophage-derived extracellular vesicles revealed cell biological processes. Finally, animal models were created to test how miR-501-3p from M2-extracellular vesicles affects tumor growth via the SET domain containing 7/DNA methyltransferase 1/suppressor of cytokine signaling 3.

RESULTS

Colon cancer increased miR-501-3p and DNA methyltransferase 1 and downregulated suppressor of cytokine signaling 3 and SET domain containing 7. miR-151-3p inhibited SET domain containing 7, upregulating DNA methyltransferase 1. Increased promoter methylation by DNA methyltransferase 1 decreased suppressor of cytokine signaling 3 expression. M2-EVs with miR-501-3p regulated the SET domain containing 7/DNA methyltransferase 1/suppressor of cytokine signaling 3 axis to induce apoptosis and colon cancer cell growth, invasion, and migration. M2-EV-delivered miR-501-3p also regulated the SET domain containing 7/DNA methyltransferase 1/suppressor of cytokine signaling 3 axis to promote tumor growth in animals.

LIMITATIONS

Further research is needed in clinical application of M2 macrophage-derived extracellular vesicles containing miR-501-3p as a biomarker of colon cancer.

CONCLUSIONS

M2 macrophage-derived extracellular vesicles with miR-501-3p regulate the SET domain containing 7/DNA methyltransferase 1/suppressor of cytokine signaling 3 axis to promote colon cancer.

LAS VESCULAS EXTRACELULARES DERIVADAS DE MACRFAGOS M QUE CONTIENEN MICROARNP PROMUEVEN LA PROGRESIN DEL CNCER DE COLON A TRAVS DEL EJE SETD/DNMT/SOCS

ANTECEDENTES:Las vesículas extracelulares derivadas de macrófagos con microARN pueden causar y desarrollar cáncer de colon.OBJETIVO:Investigamos las vesículas extracelulares derivadas de macrófagos M2 y el cáncer de colon.DISEÑO:Un estudio prospectivo y experimental de vesículas extracelulares derivadas de macrófagos M2 en el cáncer de colon.ESCENARIO:Este estudio se completó en el Cuarto Hospital de la Universidad Médica de Hebei.PACIENTES:Pacientes con cáncer de colon sometidos a resección quirúrgica.PRINCIPALES MEDIDAS DE RESULTADO:Se midieron el supresor de la señalización de citoquinas 3, miR-501-3p, SETD7 y la ADN metiltransferasa 1 en muestras de cáncer de colon. Múltiples experimentos determinaron la afinidad de unión del supresor de la señalización de citoquinas 3, de miR-501-3p, de SETD7 y de la ADN metiltransferasa 1. Los macrófagos M2 se cultivaron a partir de macrófagos M0 aislados de células mononucleares de sangre periférica de donantes sanos y se polarizaron para producir vesículas extracelulares. Las pruebas de ganancia o pérdida de función utilizando células de cáncer de colon y vesículas extracelulares derivadas de macrófagos M2 revelaron procesos biológicos celulares. Finalmente, se crearon modelos animales para probar cómo miR-501-3p de vesículas extracelulares M2 afecta el crecimiento tumoral a través del SETD7/ADN metiltransferasa 1/supresor de la señalización de citocinas 3.RESULTADOS:El cáncer de colon aumentó el miR-501-3p y la ADN metiltransferasa 1 y reguló negativamente el supresor de la señalización de citoquinas 3 y SETD7. miR-151-3p inhibió SETD7, regulando positivamente la ADN metiltransferasa 1. El aumento de la metilación del promotor por la ADN metiltransferasa 1 produjo disminución de la expresión del supresor de señalización de citocinas 3. Los M2-EV con miR-501-3p regularon el eje SETD7/ADN metiltransferasa 1/supresor de la señalización de citocinas 3 para inducir apoptosis y crecimiento, invasión y migración de células de cáncer de colon. El miR-501-3p administrado por M2-EV también reguló el eje SETD7/ADN metiltransferasa 1/supresor de la señalización de citocinas 3 para promover el crecimiento tumoral en animales.LIMITACIONES:Se necesita más investigación en la aplicación clínica de vesículas extracelulares derivadas de macrófagos M2 que contienen miR-501-3p como biomarcador de cáncer de colon.CONCLUSIONES:Las vesículas extracelulares derivadas de macrófagos M2 con miR-501-3p regulan el eje SETD7/ADN metiltransferasa 1/supresor de la señalización de citocinas 3 para promover el cáncer de colon. (Traducción-Dr. Felipe Bellolio ).

IL-6 prevents Th2 cell polarization by promoting SOCS3-dependent suppression of IL-2 signaling

Defective interleukin-6 (IL-6) signaling has been associated with Th2 bias and elevated IgE levels. However, the underlying mechanism by which IL-6 prevents the development of Th2-driven diseases remains unknown. Using a model of house dust mite (HDM)-induced Th2 cell differentiation and allergic airway inflammation, we showed that IL-6 signaling in allergen-specific T cells was required to prevent Th2 cell differentiation and the subsequent IgE response and allergic inflammation. Th2 cell lineage commitment required strong sustained IL-2 signaling. We found that IL-6 turned off IL-2 signaling during early T-cell activation and thus inhibited Th2 priming. Mechanistically, IL-6-driven inhibition of IL-2 signaling in responding T cells was mediated by upregulation of Suppressor Of Cytokine Signaling 3 (SOCS3). This mechanism could be mimicked by pharmacological Janus Kinase-1 (JAK1) inhibition. Collectively, our results identify an unrecognized mechanism that prevents the development of unwanted Th2 cell responses and associated diseases and outline potential preventive interventions.

Research Advances on Suppressor of Cytokine Signaling 3 (SOCS3) in Animal Carbohydrate and Lipid Metabolism Processes

The SOCS3 proteins played important roles in regulating the energy metabolism processes. They are crucial intracellular inhibitors related to animal obesity, immunity and inflammation. This makes SOCS3 genes very important in animal genetics and breeding. The research was conducted to investigate and explore the recent advance in the present studies on SOCS3 in animal energy and lipid metabolism processes. All the references were carefully retrieved from the PubMed database by searching key words "suppressor of cytokine signaling (SOCS)", "SOCS3", "animal carbohydrate metabolism", "animal lipid metabolism", "animal energy metabolism", "insulin resistance", "leptin", "obesity", "SOCS*" and "AMPK". All the related references retrieved were initially screened and fully reviewed for manual inspection. This effort intends to get a quick understanding and make insights into the mechanisms of Suppressor of Cytokine Signaling 3 (SOCS3) and their molecular interactions with the other cellular proteins. In this review, it was found that SOCS3 proteins could regulate cytokine receptors' signal transduction mainly through the JAK/STAT and GH/IGF-I and mTOR-STAT3-SOCS3 signaling pathways, whereas the genetic mutations or knockouts of SOCS3 genes had significant effects on animal energy metabolism. The review summarized all the relevant research reports on SOCS3 in the animal carbohydrate and lipid metabolism processes, which can provide practical reference for the genetic breeding of high-quality domestic animal breeds. It is also of great significance to further research on the genetic regulation mechanism of SOCS3 genes affecting energy metabolism and the well development of the animal breeding system.

Suppressors of cytokine signaling (SOCS) proteins in inflammatory bone disorders

Suppressor of cytokine signaling (SOCS) proteins are significant regulators of cellular immune responses. Therefore, the role of SOCS in bone-inflammatory disorders, including arthritis and periodontitis, has been investigated in experimental and clinical conditions. Recent evidence shows that SOCS proteins are expressed in major bone-related cells, including osteoblasts, osteoclasts, chondrocytes and synoviocytes, although their direct role in these cells is not fully described. These signaling molecules, especially SOCS1, 2 and 3, were shown to play critical roles in the control of bone resorption associated to inflammation. This review focuses on the involvement of SOCS proteins in inflammatory bone remodeling, including their direct and indirect role in the control of osteoclast hyperactivation, during arthritis and periodontitis. The description of the roles of SOCS proteins in inflammatory bone diseases highlights the pathways involved in the pathophysiology of these conditions and, thus, may contribute to the development and improvement of potential therapeutic interventions.

Down-regulation of hsa-miR-1264 contributes to DNMT1-mediated silencing of SOCS3

Previously we found decreased expression of SOCS3 in neointimal hyperplastic region following balloon angioplasty in atherosclerotic micro swine. In our recent in vitro studies using human coronary artery smooth muscle cells (HCASMC), we observed the inhibition of SOCS3 expression in the presence of both TNF-α and IGF-1, correlating with the in vivo findings in microswine. We also reported that two independent mechanisms, JAK/STAT3/NFκB and promoter methylation of SOCS3 were responsible for TNF-α and IGF-1 induced SOCS3 inhibition. In this study, using miRNA array and gene expression approaches, we explored the molecular mechanisms involved in the above SOCS3 repression and identified several miRNAs that are associated with the regulation of SOCS3 expression. Our miRNA expression profiling revealed profound down-regulation of two specific miRNAs, hsa-miR-758 and hsa-miR-1264, whose expression levels were decreased by 8-10 folds in HCASMCs that were treated with both TNF-α and IGF-1. This was accompanied with a significant up-regulation of three specific miRNAs, hsa-miR-155, hsa-miR-146b-5p and hsa-miR-146a, which showed about 3-7 fold increases in their expression levels. Importantly, we also found that the miRNA hsa-miR-1264 targets DNA methyltransferase-1 (DNMT1) transcripts by binding to its 3'UTR region to affect its expression. Expression of hsa-miR-1264 in HCASMCs not only resulted in decreased DNMT1 mRNA transcripts but it also increased SOCS3 expression. The treatment with TNF-α and IGF-1 resulted in drastic decrease in hsa-miR-1264 levels with no change in the expression of DNMT1. Consequently, the DNMT1 activity caused hypermethylation in the CpG island of the SOCS3 promoter region and inhibited its expression. This could be a causative epigenetic mechanism associated with TNF-α and IGF-1 induced smooth muscle cell proliferation involved in the pathogenesis of coronary artery hyperplasia and restenosis.

Fasciola hepatica Surface Coat Glycoproteins Contain Mannosylated and Phosphorylated N-glycans and Exhibit Immune Modulatory Properties Independent of the Mannose Receptor

Fascioliasis, caused by the liver fluke Fasciola hepatica, is a neglected tropical disease infecting over 1 million individuals annually with 17 million people at risk of infection. Like other helminths, F. hepatica employs mechanisms of immune suppression in order to evade its host immune system. In this study the N-glycosylation of F. hepatica’s tegumental coat (FhTeg) and its carbohydrate-dependent interactions with bone marrow derived dendritic cells (BMDCs) were investigated. Mass spectrometric analysis demonstrated that FhTeg N-glycans comprised mainly of oligomannose and to a lesser extent truncated and complex type glycans, including a phosphorylated subset. The interaction of FhTeg with the mannose receptor (MR) was investigated. Binding of FhTeg to MR-transfected CHO cells and BMDCs was blocked when pre-incubated with mannan. We further elucidated the role played by MR in the immunomodulatory mechanism of FhTeg and demonstrated that while FhTeg’s binding was significantly reduced in BMDCs generated from MR knockout mice, the absence of MR did not alter FhTeg’s ability to induce SOCS3 or suppress cytokine secretion from LPS activated BMDCs. A panel of negatively charged monosaccharides (i.e. GlcNAc-4P, Man-6P and GalNAc-4S) were used in an attempt to inhibit the immunoregulatory properties of phosphorylated oligosaccharides. Notably, GalNAc-4S, a known inhibitor of the Cys-domain of MR, efficiently suppressed FhTeg binding to BMDCs and inhibited the expression of suppressor of cytokine signalling (SOCS) 3, a negative regulator the TLR and STAT3 pathway. We conclude that F. hepatica contains high levels of mannose residues and phosphorylated glycoproteins that are crucial in modulating its host’s immune system, however the role played by MR appears to be limited to the initial binding event suggesting that other C-type lectin receptors are involved in the immunomodulatory mechanism of FhTeg.

Fascioliasis, caused by the liver fluke Fasciola hepatica, is a neglected tropical disease infecting over 1 million individuals annually with 17 million people at risk of infection. These worms infect the liver and can survive for many years in its animal or human host because they supress the host’s immune system that is important in clearing worm infection. Worms are similar to humans in that they are made of proteins, fats and sugars, and while there are many studies on worm proteins, few studies have examined the sugars. We are interested in the sugars because we believe that they help the parasite survive for many years within its host. To examine this, we have used a technique called mass spectrometric analysis to characterise the sugars present in F. hepatica. We also have developed systems in the laboratory to test if these sugars can suppress the host’s immune system. We conclude that F. hepatica sugars are crucial in suppressing its host’s immune system; however, the exact way the sugars can do this requires further studies. These studies are important for the development of worm vaccines or therapies.

Hypoxic Conditioned Medium From Human Adipose-Derived Stem Cells Promotes Mouse Liver Regeneration Through JAK/STAT3 Signaling

Adipose-derived stem cells (ASCs) mainly exert their function by secreting materials that are collectively termed the secretome. Despite recent attention to the secretome as an alternative to stem cell therapy, the culture conditions for generating optimal secretome contents have not been determined. Therefore, we investigated the role of hypoxic-conditioned media (HCM) from ASCs. Normoxic-conditioned media (NCM) and HCM were obtained after culturing ASCs in 20% O2 or 1% O2 for 24 hours, respectively. Subsequently, partially hepatectomized mice were infused with saline, control medium, NCM, or HCM, and then sera and liver specimens were obtained for analyses. Hypoxia (1% O2) significantly increased mRNA expression of mediators from ASCs, including interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), hepatocyte growth factor (HGF), and vascular endothelial growth factor (VEGF). HCM infusion significantly increased the number of Ki67-positive cells in the liver (p < .05). HCM infusion significantly increased phospho-signal transducer and activator of transcription 3 (STAT3) and decreased suppressor of cytokine signaling 3 (SOCS3) expression in the liver (p < .05). To determine the role of IL-6 in liver regeneration, we then performed IL-6 RNA interference study. Conditioned media (CM) obtained from ASCs, which were transfected with either siIL-6 or siControl, were administered to partially hepatectomized mice. The siIL-6 CM groups exhibited lower liver proliferation (Ki67-positive cells) and markers of regeneration (protein expression of proliferating cell nuclear antigen, p-STAT3, HGF, and VEGF and liver weights) than the siControl CM groups (p < .05). Taken together, hypoxic preconditioning of ASCs increased expression of mediators promoting anti-inflammatory and regenerative responses. The liver regenerative effects of HCM appear to be mediated by persistent and uninhibited expression of STAT3 in the liver, which results from decreased expression of SOCS3.

SIGNIFICANCE

In this study, it was found that treatment with the medium from hypoxic-preconditioned adipose-derived stem cells (ASCs) increased the viability of hepatotoxic hepatocytes and enhance liver regeneration in partially hepatectomized mice. In addition, the researchers first revealed that the hepatoprotective effects of hypoxic-conditioned media are mediated by persistent and uninhibited expression of signal transducer and activator of transcription 3 in the liver, which result from a decreased expression of suppressor of cytokine signaling 3. Therefore, the hypoxic preconditioning of ASCs is expected to play a crucial role in regenerative medicine by optimizing the production of a highly effective secretome from ASCs.

Fatness rather than leptin sensitivity determines the timing of puberty in female mice

Leptin is a permissive factor for the onset of puberty. However, changes in adiposity frequently influence leptin sensitivity. Thus, the objective of the present study was to investigate how changes in body weight, fatness, leptin levels and leptin sensitivity interact to control the timing of puberty in female mice. Pre-pubertal obesity, induced by raising C57BL/6 mice in small litters, led to an early puberty onset. Inactivation of Socs3 gene in the brain or exclusively in leptin receptor-expressing cells reduced the body weight and leptin levels at pubertal onset, and increased leptin sensitivity. Notably, these female mice exhibited significant delays in vaginal opening, first estrus and onset of estrus cyclicity. In conclusion, our findings suggest that increased leptin sensitivity did not play an important role in favoring pubertal onset in female mice. Rather, changes in pubertal body weight, fatness and/or leptin levels were more important in influencing the timing of puberty.

Suppressors of cytokine signalling in ankylosing spondylitis and their associations with disease severity, acute-phase reactants and serum cytokines

OBJECTIVES

To investigate the suppressors of cytokine signalling (SOCS1 and SOCS3) expression in peripheral blood cells in ankylosing spondylitis (AS), and their associations with clinical and laboratory manifestations.

METHODS

The levels of SOCS1 and SOCS3 mRNA in peripheral blood mononuclear cells (PBMCs), T cells and monocytes were measured by RT-PCR in 53 AS patients and 31 healthy controls. Patient's serum IL-6, IL-10 and IL-17A levels were determined by ELISA. We evaluated patient's disease activity, functional ability and global assessment, and tested their ESR, CRP and IgA levels.

RESULTS

Cellular SOCS1 expression did not show significant differences between AS patients and controls. However, T cells SOCS1 decreased significantly in the AS subgroup with lower ESR than controls (p=0.013). PBMCs (p=0.047) and T cells (p=0.035) SOCS1 decreased significantly in the AS subgroup with lower CRP than controls. Importantly, SOCS3 expression increased significantly in AS patients compared to the controls in PBMCs (p=0.025), T cells (p=0.003) and monocytes (p=0.009). Moreover, PBMCs SOCS3 correlated with ESR (r=0.297, p=0.031) and CRP (r=0.320, p=0.019). T cells SOCS3 correlated with BASFI (r=0.337, p=0.015), ESR (r=0.435, p=0.001) and CRP (r=0.300, p=0.029). Monocytes SOCS3 correlated with ESR (r=0.281, p=0.041) and IgA (r=0.426, p=0.006). Furthermore, T cells SOCS1 (r=-0.454, p=0.023) and T cells SOCS3 (r=-0.405, p=0.045) negatively correlated with serum IL-17A. Monocytes SOCS3 negatively correlated with serum IL-6 (r=-0.584, p=0.002).

CONCLUSIONS

The decreased SOCS1 and increased SOCS3 expression in AS PBMCs and T cells, and their correlation with patient's functional ability, acute-phase reactants and serum pro-inflammatory cytokines suggested that SOCS may participate in the pathogenesis of AS.

SOCS3 Expressed in M2 Macrophages Attenuates Contact Hypersensitivity by Suppressing MMP-12 Production

Numerous studies have clarified the immunological mechanisms of contact hypersensitivity (CHS). In addition, we have recently shown that M2 macrophages play key roles in the development of CHS by producing matrix metalloproteinase-12 (MMP-12). However, regulatory mechanisms of the elicitation phase in CHS remain largely unknown. To determine the roles of suppressor of cytokine signaling (SOCS) family members in M2 macrophages in the regulation of CHS, we investigated the expression of SOCS family members in M2 macrophages at the inflammatory sites of CHS. Transcriptome analysis revealed that among SOCS family members, SOCS3 was highly expressed in M2 macrophages at the site of CHS, and SOCS3 induction was reduced by IFN-? neutralization. 2,4-Dinitrofluorobenzene-induced CHS was significantly enhanced and prolonged in mice lacking SOCS3 expression in monocytes/macrophages (SOCS3(?/?) mice) compared with that in control mice. Importantly, expression of MMP-12 in M2 macrophages was significantly increased in SOCS3(?/?) mice at the site of CHS, and deletion of the MMP-12 gene reduced the exacerbated CHS in SOCS3(?/?) mice. Finally, IFN-? inhibited IL-4-induced MMP-12 expression in a SOCS3-dependent manner. Taken together, these results suggest that SOCS3 expressed in M2 macrophages is involved in the attenuation and/or resolution of CHS, presumably by suppressing MMP-12 production.

Endogenous galectin-3 expression levels modulate immune responses in galectin-3 transgenic mice

Galectin-3 (Gal-3), a β-galactoside-binding mammalian lectin, is involved in cancer progression and metastasis. However, there is an unmet need to identify the underlying mechanisms of cancer metastasis mediated by endogenous host galectin-3. Galectin-3 is also known to be an important regulator of immune responses. The present study was aimed at analysing how expression of endogenous galectin-3 regulates host immunity and lung metastasis in B16F10 murine melanoma model. Transgenic Gal-3(+/-) (hemizygous) and Gal-3(-/-) (null) mice exhibited decreased levels of Natural Killer (NK) cells and lower NK mediated cytotoxicity against YAC-1 tumor targets, compared to Gal-3(+/+) (wild-type) mice. On stimulation, Gal-3(+/-) and Gal-3(-/-) mice splenocytes showed increased T cell proliferation than Gal-3(+/+) mice. Intracellular calcium flux was found to be lower in activated T cells of Gal-3(-/-) mice as compared to T cells from Gal-3(+/+) and Gal-3(+/-) mice. In Gal-3(-/-) mice, serum Th1, Th2 and Th17 cytokine levels were found to be lowest, exhibiting dysregulation of pro-inflammatory and anti-inflammatory cytokines balance. Marked decrease in serum IFN-γ levels and splenic IFN-γR1 (IFN-γ Receptor 1) expressing T and NK cell percentages were observed in Gal-3(-/-) mice. On recombinant IFN-γ treatment of splenocytes in vitro, Suppressor of Cytokine Signaling (SOCS) 1 and SOCS3 protein expression was higher in Gal-3(-/-) mice compared to that in Gal-3(+/+) and Gal-3(+/-) mice; suggesting possible attenuation of Signal Transducer and Activator of Transcription (STAT) 1 mediated IFN-γ signaling in Gal-3(-/-) mice. The ability of B16F10 melanoma cells to form metastatic colonies in the lungs of Gal-3(+/+) and Gal-3(-/-) mice remained comparable, whereas it was found to be reduced in Gal-3(+/-) mice. Our data indicates that complete absence of endogenous host galectin-3 facilitates lung metastasis of B16F10 cells in mice, which may be contributed by dysregulated immune responses resulting from decreased NK cytotoxicity, disturbed serum Th1, Th2, Th17 cytokine milieu, reduced serum IFN-γ levels and attenuation of splenic STAT1 mediated IFN-γ signalling in Gal-3(-/-) mice.

Ac2PIM-responsive miR-150 and miR-143 target receptor-interacting protein kinase 2 and transforming growth factor beta-activated kinase 1 to suppress NOD2-induced immunomodulators

Specific and coordinated regulation of innate immune receptor-driven signaling networks often determines the net outcome of the immune responses. Here, we investigated the cross-regulation of toll-like receptor (TLR)2 and nucleotide-binding oligomerization domain (NOD)2 pathways mediated by Ac2PIM, a tetra-acylated form of mycobacterial cell wall component and muramyl dipeptide (MDP), a peptidoglycan derivative respectively. While Ac2PIM treatment of macrophages compromised their ability to induce NOD2-dependent immunomodulators like cyclooxygenase (COX)-2, suppressor of cytokine signaling (SOCS)-3, and matrix metalloproteinase (MMP)-9, no change in the NOD2-responsive NO, TNF-α, VEGF-A, and IL-12 levels was observed. Further, genome-wide microRNA expression profiling identified Ac2PIM-responsive miR-150 and miR-143 to target NOD2 signaling adaptors, RIP2 and TAK1, respectively. Interestingly, Ac2PIM was found to activate the SRC-FAK-PYK2-CREB cascade via TLR2 to recruit CBP/P300 at the promoters of miR-150 and miR-143 and epigenetically induce their expression. Loss-of-function studies utilizing specific miRNA inhibitors establish that Ac2PIM, via the miRNAs, abrogate NOD2-induced PI3K-PKCδ-MAPK pathway to suppress β-catenin-mediated expression of COX-2, SOCS-3, and MMP-9. Our investigation has thus underscored the negative regulatory role of Ac2PIM-TLR2 signaling on NOD2 pathway which could broaden our understanding on vaccine potential or adjuvant utilities of Ac2PIM and/or MDP.

The Prognostic Role of SOCS3 and A20 in Human Cholangiocarcinoma

As an antagonist of the JAK/STAT pathway, suppressor of cytokine signaling 3 (SOCS3) plays an integral role in shaping the inflammatory environment, tumorigenesis and disease progression in cholangiocarcinoma (CCA); however, its prognostic significance remains unclear. Although tumor necrosis factor α-induced protein 3 (TNFAIP3, also known as A20) can decrease SOCS3 expression and is involved in the regulation of tumorigenesis in certain malignancies, its role in CCA remains unknown. In this study, we investigated the expression of SOCS3 and A20 in human CCA tissues to assess the prognostic significance of these proteins. The expression of SOCS3 and A20 was initially detected by western blot in 22 cases of freshly frozen CCA tumors with corresponding peritumoral tissues and 22 control normal bile duct tissues. Then, these proteins were investigated in 86 CCA patients by immunohistochemistry (IHC) and were evaluated for their association with clinicopathological parameters in human CCA. The results indicated that SOCS3 expression was significantly lower in CCA tumor tissues than in corresponding peritumoral biliary tissues and normal bile duct tissues. Conversely, A20 was overexpressed in CCA tissues. Thus, an inverse correlation between the expression of SOCS3 and A20 was discovered. Furthermore, patients with low SOCS3 expression or high A20 expression showed a dramatically lower overall survival rate. These proteins were both associated with CCA lymph node metastasis, postoperative recurrence and overall survival rate. However, only A20 showed a significant association with the tumor node metastasis (TNM) stage, while SOCS3 showed a significant association with tumor differentiation. Multivariate Cox analysis revealed that SOCS3 and A20 were independent prognostic indicators for overall survival in CCA. Thus, our study demonstrated that SOCS3 and A20 represent novel prognostic factors for human CCA.

Genes Involved in Maintaining the Bone Marrow Stroma Are Dysregulated in Patients with Myelofibrosis: Lenalidomide Treatment Up-regulates SOCS3

AIM

The purpose of the present study was to determine whether genes involved in the organization of the hematopoietic niche were dysregulated in patients with primary myelofibrosis (MF) treated with lenalidomide.

MATERIALS AND METHODS

We used reverse-transcription quantitative polymerase chain reaction to study the expression of a set of genes involved in the organization of the hematopoietic niche in peripheral blood and bone marrow (BM) mononuclear cell (MNC) samples from 32 patients with primary MF who participated in a phase II trial of lenalidomide plus prednisone.

RESULTS

At baseline (before treatment) cyclo-oxygenase 2 (COX2) was significantly up-regulated, while chemokine (C-X-C motif) receptor 4 (CXCR4), paired box 5 (PAX5) C-terminus, and hypoxia inducible factor 1A (HIF1A) were significantly down-regulated in BM MNCs from patients with primary MF compared to BM MNCs from healthy individuals. After 9 months of treatment, the expression of suppressor of cytokine signaling 3 (SOCS3) was significantly increased.

CONCLUSION

Patients with primary MF showed aberrant expression of several genes involved in maintaining BM homeostasis and our findings suggest that treatment with lenalidomide plus prednisone up-regulates SOCS3.

SOCS3 Genetic Polymorphism Is Associated With Clinical Features and Prognosis of Hepatocellular Carcinoma Patients Receiving Hepatectomy

Previous studies showed that suppressor of cytokine signaling 3 (SOCS3) protein is associated with incidence and progression of hepatocellular carcinoma (HCC); however, the association between the genetic polymorphism of SOCS3 gene and HCC remains unknown. A total of 254 HCC patients and 354 healthy controls were enrolled. All HCC patients underwent partial hepatectomy as initial treatment and were followed. Three SOCS3 gene polymorphisms, namely, rs4969170 A>G, rs8064821 C>T, and rs12953258 C>A were determined. Our data show that the rs4969170 A>G polymorphism dramatically affects the susceptibility to HCC in our cohorts. Logistic regression analyses revealed that the rs4969170 GG is a risk factor for HCC after the adjustment with confounding factors. The rs4969170A>G polymorphism is also associated with the clinical features of HCC patients and predicts the postoperative relapse-free survival and overall survival. The rs4969170GG genotype carrier had a worse prognosis than the rs4969170AG and rs4969170AA carrier. Our findings suggest that the rs4969170A>G polymorphism of SOCS3 gene may be used as a prognostic predictor for HCC patients who underwent surgical treatment.

Effects of Reducing Suppressors of Cytokine Signaling-3 (SOCS3) Expression on Dendritic Outgrowth and Demyelination after Spinal Cord Injury

Suppressors of cytokine signaling-3 (SOCS3) is associated with limitations of nerve growth capacity after injury to the central nervous system. Although genetic manipulations of SOCS3 can enhance axonal regeneration after optic injury, the role of SOCS3 in dendritic outgrowth after spinal cord injury (SCI) is still unclear. The present study investigated the endogenous expression of SOCS3 and its role in regulating neurite outgrowth in vitro. Interleukin-6 (IL-6) induces SOCS3 expression at the mRNA and protein levels in neuroscreen-1 (NS-1) cells. In parallel to SOCS3 expression, IL-6 induced tyrosine phosphorylation of signal transducer and activator of transcription 3 (STAT3) in NS-1 cells. Lentiviral delivery of short hairpin RNA (shSOCS3) (Lenti-shSOCS3) to decrease SOCS3 expression into NS-1 cells enhanced IL-6-induced tyrosine phosphorylation of STAT3 (P-STAT3 Tyr705) and promoted neurite outgrowth. In addition, we determined if reduction of SOCS3 expression by microinjection of Lenti-shSOCS3 into spinal cord enhances dendrite outgrowth in spinal cord neurons after SCI. Knocking down of SOCS3 in spinal cord neurons with Lenti-shSOCS3 increased complete SCI-induced P-STAT3 Tyr705. Immunohistochemical analysis showed that complete SCI induced a significant reduction of microtubule association protein 2-positive (MAP-2+) dendrites in the gray and white matter at 1 and 4 weeks after injury. The SCI-induced reduction of MAP-2+ dendrites was inhibited by infection with Lenti-shSOCS3 in areas both rostral and caudal to the lesion at 1 and 4 weeks after complete SCI. Furthermore, shSOCS3 treatment enhanced up-regulation of growth associated protein-43 (GAP-43) expression, which co-localized with MAP-2+ dendrites in white matter and with MAP-2+ cell bodies in gray matter, indicating Lenti-shSOCS3 may induce dendritic regeneration after SCI. Moreover, we demonstrated that Lenti-shSOCS3 decreased SCI-induced demyelination in white matter of spinal cord both rostral and caudal to the injury site 1 week post-injury, but not rostral to the injury at 4 weeks post-injury. Importantly, similar effects as Lenti-shSOCS3 on increasing MAP-2+ intensity and dendrite length, and preventing demyelination were observed when a second shSOCS3 (Lenti-shSOCS3 #2) was applied to rule out the possibilities of off target effects of shRNA. Collectively, these results suggest that knocking down of SOCS3 enhances dendritic regeneration and prevents demyelination after SCI.

A novel role of the checkpoint kinase ATR in leptin signaling

In a world with increasing incidences of obesity, it becomes critical to understand the detailed regulation of appetite. To identify novel regulators of the signaling mediated by one of the key hormones of energy homeostasis, leptin, we screened a set of compounds for their effect on the downstream Signal Transducer and Activator of Transcription 3 (STAT3) signaling. Interestingly, cells exposed to inhibitors of the Ataxia Telangiectasia and RAD3-related protein ATR increased their leptin dependent STAT3 activity. This was due to failure of the cells to induce the negative feedback mediator Suppressor of Cytokine Signaling 3 (SOCS3), suggesting that ATR has a previously unknown role in the negative feedback regulation of leptin signaling. This is an important finding not only because it sheds light on additional genes involved in leptin signaling, but also because it brings forward a new potential therapeutic intervention point for increasing leptin signaling in obese individuals.

GH signaling in human adipose and muscle tissue during 'feast and famine': amplification of exercise stimulation following fasting compared to glucose administration

OBJECTIVE

Fasting and exercise stimulates, whereas glucose suppresses GH secretion, but it is uncertain how these conditions impact GH signaling in peripheral tissues. To test the original 'feast and famine hypothesis' by Rabinowitz and Zierler, according to which the metabolic effects of GH are predominant during fasting, we specifically hypothesized that fasting and exercise act in synergy to increase STAT-5b target gene expression.

DESIGN AND METHODS

Eight healthy men were studied on two occasions in relation to a 1 h exercise bout: i) with a concomitant i.v. glucose infusion ('feast') and ii) after a 36 h fast ('famine'). Muscle and fat biopsy specimens were obtained before, immediately after, and 30 min after exercise.

RESULTS

GH increased during exercise on both examination days and this effect was amplified by fasting, and free fatty acid (FFA) levels increased after fasting. STAT-5b phosphorylation increased similarly following exercise on both occasions. In adipose tissue, suppressors of cytokine signaling 1 (SOCS1) and SOCS2 were increased after exercise on the fasting day and both fasting and exercise increased cytokine inducible SH2-containing protein (CISH). In muscle, SOCS2 and CISH mRNA were persistently increased after fasting. Muscle SOCS1, SOCS3, and CISH mRNA expression increased, whereas SOCS2 decreased after exercise on both examination days.

CONCLUSIONS

This study demonstrates that fasting and exercise act in tandem to amplify STAT-5b target gene expression (SOCS and CISH) in adipose and muscle tissue in accordance with the 'feast and famine hypothesis'; the adipose tissue signaling responses, which hitherto have not been scrutinized, may play a particular role in promoting FFA mobilization.

Hepatitis C Virus Driven AXL Expression Suppresses the Hepatic Type I Interferon Response

Treatment of chronic hepatitis C virus (HCV) infection is evolving rapidly with the development of novel direct acting antivirals (DAAs), however viral clearance remains intimately linked to the hepatic innate immune system. Patients demonstrating a high baseline activation of interferon stimulated genes (ISGs), termed interferon refractoriness, are less likely to mount a strong antiviral response and achieve viral clearance when placed on treatment. As a result, suppressor of cytokine signalling (SOCS) 3 and other regulators of the IFN response have been identified as key candidates for the IFN refractory phenotype due to their regulatory role on the IFN response. AXL is a receptor tyrosine kinase that has been identified as a key regulator of interferon (IFN) signalling in myeloid cells of the immune system, but has not been examined in the context of chronic HCV infection. Here, we show that AXL is up-regulated following HCV infection, both in vitro and in vivo and is likely induced by type I/III IFNs and inflammatory signalling pathways. AXL inhibited type IFNα mediated ISG expression resulting in a decrease in its antiviral efficacy against HCV in vitro. Furthermore, patients possessing the favourable IFNL3 rs12979860 genotype associated with treatment response, showed lower AXL expression in the liver and a stronger induction of AXL in the blood, following their first dose of IFN. Together, these data suggest that elevated AXL expression in the liver may mediate an IFN-refractory phenotype characteristic of patients possessing the unfavourable rs12979860 genotype, which is associated with lower rates of viral clearance.

Immature B Cell Egress from Bone Marrow Is SOCS3 Independent

Suppressor of cytokine signaling (SOCS)-3 has been suggested to regulate CXCR4 signaling in a variety of human cell lines. In mice, conditional SOCS3 inactivation in hematopoietic cells including B-lineage lymphocytes has been reported to exacerbate CXCR4-signaling and focal adhesion kinase phosphorylation, which resulted in altered immature B cell distribution in bone marrow (BM) due to sustained α4β1 integrin-mediated adhesion to the extracellular matrix. However, a recent study examining conditional SOCS3 deletion specifically in B-lineage cells failed to detect significant roles in B-lineage cell retention in BM. In this study we carefully examined the role played by SOCS3 in CXCR4 signaling in developing B cell subsets. We show that in mice conditionally deficient in SOCS3 exclusively in B cells (Socs3fl/fl Mb1cre/+) there was no detectable difference in B cell development in BM and in periphery. We show that SOCS3 deficient and sufficient immature B cell subsets are similarly distributed between BM parenchyma and sinusoids, and are equally competent at exiting BM into peripheral blood. Furthermore, we found no significant differences in CXCR4 desensitization upon ligand exposure in developing B lymphocyte subsets. Consequently, SOCS3-deficient and sufficient B-lineage cell migration towards CXCL12 in vitro was undistinguishable, and B-lineage cell amoeboid motility within BM parenchyma was also unaffected by SOCS3-deficiency. Thus we conclude that SOCS3 has no detectable influence on biological processes known to be controlled by CXCR4 signaling.

Promotion of Erythropoietic Differentiation in Hematopoietic Stem Cells by SOCS3 Knock-Down

Suppressor of cytokine signaling 3 (SOCS3) plays an important role in mice fetal liver erythropoiesis, but the roles of SOCS3 in human hematopoietic stem cells (HSCs) have not been well investigated. In the present study, lentiviral small interference RNA expression vectors (shRNA) of SOCS3 were constructed and stably transferred into HSCs. We found that SOCS3 knockdown induced erythroid expansion in HSCs. Conversely, Ectopic expression of SOCS3 in progenitor cells blocked erythroid expansion and erythroid colony formation of HSCs. To further explore the involved mechanism, we compared gene expression profiles of SOCS3-shRNA tranduced HSCs with that of control HSCs by whole genome microarrays. The results indicated that cell developmental process related genes, especially hematopoietic lineage-specific genes, associated with the responses to SOCS3 in HSCs.Downexpression of SOCS3 in HSCs or differentiated erythroid progenitor cells induced a transcriptional program enriched for erythroid development relative genes. Our results proved that SOCS3 down-expression induced lineage commitment towards erythroid progenitor cell fate by activation of erythroid-specific gene in HSCs and provided new insight into the mechanism of erythropoietic development.

Genetic correlation of SOCS3 polymorphisms with infantile asthma: an evidence based on a case-control study

OBJECTIVE

In order to explore the relevance of SOCS3 gene polymorphisms with infantile asthma and provide evidence for the ethology of infantile asthma, we conducted this case-control study.

METHODS

A total of 273 children were enrolled for study in this article, including 119 children with asthma and 154 healthy controls frequency-matched with the former in sex and age. The genotyping of SOCS3 rs4969170, rs4969168 polymorphisms in all subjects were performed using TaqMan probe method. Odds ratio (OR) with 95% confidence interval (CI) was used to represent the association strength between SOCS3 polymorphisms and infantile asthma and calculated by χ² test which was conducted to check the Hardy-Weinberg equilibrium (HWE) in the control group.

RESULTS

The genotypes distributions of SOCS3 polymorphisms in controls conformed to HWE. Compared with GG/GA genotype in SOCS3 rs4969170, AA genotype obviously increased the susceptibility to asthma in children (OR=2.556, 95% CI=1.377-4.744) and A allele also made the same conclusion (OR=2.287, 95% CI=1.311-3.991). Differently in rs4969168, AG and AG/GG genotypes distributions had significant differences in two groups (P=0.036, 0.043). This two polymorphisms existed the linkage disequilibrium and the haplotype analysis showed that A-G and A-A haplotypes in rs4969170-rs4969168 increased 1.855 and 0.863 times risk of asthma development in children, respectively.

CONCLUSIONS

A significant relevance involved in SOCS3 gene polymorphisms and infantile asthma development based on a Chinese Han population.

Out-of-Sequence Signal 3 Paralyzes Primary CD4(+) T-Cell-Dependent Immunity

Primary T cell activation involves the integration of three distinct signals delivered in sequence: (1) antigen recognition, (2) costimulation, and (3) cytokine-mediated differentiation and expansion. Strong immunostimulatory events such as immunotherapy or infection induce profound cytokine release causing "bystander" T cell activation, thereby increasing the potential for autoreactivity and need for control. We show that during strong stimulation, a profound suppression of primary CD4(+) T-cell-mediated immune responses ensued and was observed across preclinical models and patients undergoing high-dose interleukin-2 (IL-2) therapy. This suppression targeted naive CD4(+) but not CD8(+) T cells and was mediated through transient suppressor of cytokine signaling-3 (SOCS3) inhibition of the STAT5b transcription factor signaling pathway. These events resulted in complete paralysis of primary CD4(+) T cell activation, affecting memory generation and induction of autoimmunity as well as impaired viral clearance. These data highlight the critical regulation of naive CD4(+) T cells during inflammatory conditions.

Suppressor of cytokine signaling 3 A+930-->G (rs4969168) polymorphism is associated with apolipoprotein A1 and low-density lipoprotein cholesterol

This study aimed to detect the association of the suppressor of cytokine signaling 3 gene (SOCS3) A+930-->G (rs4969168) single nucleotide polymorphism (SNP) and environmental factors with serum lipid levels in the Han and Mulao populations. Genotyping of the SOCS3 A+930-->G (rs4969168) SNP was performed in 752 of Han and 690 of Mulao participants using polymerase chain reaction and restriction fragment length polymorphism. The genotype and allele frequencies were significantly different between the Han and Mulao populations (GG, 57.71% vs. 51.16%, GA, 36.97% vs. 41.16%, AA, 5.32% vs. 7.68%, P = 0.023; G, 76.20% vs. 71.74%, A, 23.80% vs. 28.26%; P = 0.006; respectively). Serum apolipoprotein (Apo) A1 levels in Han were different among the genotypes (P < 0.05). Subgroup analyses showed that the levels of ApoA1 in Han females, and ApoA1 and low-density lipoprotein cholesterol (LDL-C) in Mulao males were different among the genotypes (P < 0.05). Serum lipid parameters were also associated with several environmental factors in both ethnic groups (P < 0.05-0.001). These findings suggest that there may be a racial/ethnic- and/or sex-specific association between the SOCS3 A+930-->G (rs4969168) SNP and serum lipid parameters in some populations.

Bacterial extract OM-85 BV protects mice against experimental chronic rhinosinusitis

OBJECTIVES

To investigate the therapeutic effects of OM-85 BV as an adjunctive treatment on experimental chronic rhinosinusitis (CRS) in mice.

METHODOLOGY

Female BALB/c mice aged 8-12 weeks were sensitized and administrated by intranasal Aspergillus fumigatis (AF) three times per week for 1 week, 3 weeks, 2 months and 3 months (n = 10 each time point). The mice were randomly and equally assigned to four groups: normal control group, model group, OM-85-BV plus amoxicillin group, and isolated amoxicillin group. Inflammatory changes were determined by hematoxylin-eosin (HE) staining. The expression levels of suppressor of cytokine signaling (SOCS) 1, SOCS3, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ in samples were assessed by using real-time PCR (RT-PCR) and Western blotting.

RESULTS

There were significantly inflammatory and structural changes between the model and other groups. Compared to the model group, the mRNA expression levels of SOCS1, SOCS3, TNF-α, and IFN-γ were significantly decreased in OM-85-BV plus amoxicillin group and isolated amoxicillin group, along with the protein levels.

CONCLUSION

The bacterial extract OM-85 BV is a low-cost alternatively adjunctive drug to treat CRS with simple oral administration, good safety, and few side effects.

Sodium salicylate reduced insulin resistance in the retina of a type 2 diabetic rat model

Sodium salicylate has been reported to reduce markers of diabetic retinopathy in a type 1 rat model. Because rates of type 2 diabetes are on the rise, we wanted to determine whether salicylate could improve insulin resistance in a type 2 rat model, as well as improve retinal function. We treated lean and obese BBZDR/Wor type 2 diabetic rats with salicylate in their chow for 2 months. Prior to salicylate treatment, rats underwent an electroretinogram to measure retinal function. After 2 months of treatment, rats underwent an additional electroretinogram prior to sacrifice. In addition to the animal model, we also treated retinal endothelial cells (REC) and rat Müller cells with salicylate and performed the same analyses as done for the rat retinal lysates. To investigate the role of salicylate in insulin signaling, we measured TNFα and caspase 3 levels by ELISA, as well as performed Western blotting for insulin receptor substrate 1, insulin receptor, SOCS3, and pro- and anti-apoptotic markers. Data demonstrated that salicylate significantly improved retinal function, as well as reduced TNFα and SOCS3-induced insulin resistance in all samples. Overall, results suggest that salicylate is effective in reducing insulin resistance in the retina of type 2 diabetic rat models.

Phosphodiesterase-3B-cAMP pathway of leptin signalling in the hypothalamus is impaired during the development of diet-induced obesity in FVB/N mice

The phosphodiesterase-3B (PDE3B)-cAMP pathway plays an important role in transducing the action of leptin in the hypothalamus. Obesity is usually associated with hyperleptinaemia and resistance to anorectic and body weight-reducing effects of leptin. To determine whether the hypothalamic PDE3B-cAMP pathway of leptin signalling is impaired during the development of diet-induced obesity (DIO), we fed male FVB/N mice a high-fat diet (HFD: 58% kcal as fat) or low-fat diet (LFD: 6% kcal as fat) for 4 weeks. HFD fed mice developed DIO in association with hyperphagia, hyperleptinaemia and hyperinsulinaemia. Leptin (i.p.) significantly increased hypothalamic PDE3B activity and phosphorylated (p)-Akt levels in LFD-fed but not in HFD-fed mice. However, basal p-Akt levels in hypothalamus were increased in DIO mice. Additionally, amongst six-microdissected brain nuclei examined, leptin selectively decreased cAMP levels in the arcuate nucleus (ARC) of LFD-fed mice but failed to do so in HFD-fed mice. We next tested whether both the PBE3B and Akt pathways of leptin signalling remained impaired in DIO mice on the HFD for 12 weeks (long-term). DIO mice were hyperinsulinaemic and hyperleptinaemic in association with impaired glucose and insulin tolerance. Although, in LFD-fed mice, leptin significantly increased PDE3B activity and p-Akt levels in the hypothalamus, it failed to do so in HFD-fed mice. Also, basal p-Akt levels in the hypothalamus were increased in DIO mice and leptin had no further effect. Similarly, immunocytochemistry showed that leptin increased the number of p-Akt-positive cells in the ARC of LFD-fed but not in HFD-fed mice, and there was an increased basal number of p-Akt positive cells in the ARC of DIO mice. These results suggest that the PDE3B-cAMP- and Akt-pathways of leptin signalling in the hypothalamus are impaired during the development of DIO. Thus, a defect in the regulation by leptin of the hypothalamic PDE3B-cAMP pathway and Akt signalling may be one of the mechanisms of central leptin resistance and the development of DIO.

SOCS3 silencing attenuates eosinophil functions in asthma patients

Eosinophils are one of the key inflammatory cells in asthma. Eosinophils can exert a wide variety of actions through expression and secretion of multiple molecules. Previously, we have demonstrated that eosinophils purified from peripheral blood from asthma patients express high levels of suppressor of cytokine signaling 3 (SOCS3). In this article, SOCS3 gene silencing in eosinophils from asthmatics has been carried out to achieve a better understanding of the suppressor function in eosinophils. SOCS3 siRNA treatment drastically reduced SOCS3 expression in eosinophils, leading to an inhibition of the regulatory transcription factors GATA-3 and FoxP3, also interleukin (IL)-10; in turn, an increased STAT3 phosphorilation was observed. Moreover, SOCS3 abrogation in eosinophils produced impaired migration, adhesion and degranulation. Therefore, SOCS3 might be regarded as an important regulator implicated in eosinophil mobilization from the bone marrow to the lungs during the asthmatic process.

Down-regulation of suppressor of cytokine signaling 3 by miR-122 enhances interferon-mediated suppression of hepatitis B virus

MicroRNA-122 (miR-122) is involved in the pathogenesis of several liver diseases, including chronic hepatitis B infection and hepatocellular carcinoma. This study aimed to explore the potential role of miR-122 in the interferon (IFN)-mediated suppression of hepatitis B virus (HBV) in hepatocytes. We found that elevated expression of suppressor of cytokine signaling 3 (SOCS3) following HBV infection, contributed to the inactivation of the IFN signaling pathway. Based on previous studies from our laboratory showing that miR-122 can modulate type I IFN expression by inhibiting SOCS1 expression, we analyzed the SOCS3 mRNA sequence for putative miR-122 binding sites. We demonstrate that miR-122 inhibits SOCS3 expression by targeting the 3'-untranslated region of the SOCS3 mRNA within the region 1887-1910 nucleotides. Finally, we demonstrate that significantly increased levels of IFN lead to decreased HBV expression in miR-122 mimic-treated Huh7 cells, whereas inhibition of endogenous miR-122 leads to enhanced viral production, owing to a marked decrease in IFN expression. Taken together, our results demonstrate that miR-122 down-regulates SOCS3, thus positively affecting the anti-HBV efficiency of endogenous type I IFN. Our study suggests that suppression of miR-122 induced by HBV infection, leads to the inactivation of IFN expression, which in turn enhances HBV replication, contributing to viral persistence and hepatocarcinogenesis.

MicroRNA-185 targets SOCS3 to inhibit beta-cell dysfunction in diabetes

Diabetes is the most common and complex metabolic disorder, and one of the most important health threats now. MicroRNAs (miRNAs) are a group of small non-coding RNAs that have been suggested to play a vital role in a variety of physiological processes, including glucose homeostasis. In this study, we investigated the role of miR-185 in diabetes. MiR-185 was significantly downregulated in diabetic patients and mice, and the low level was correlated to blood glucose concentration. Overexpression of miR-185 enhanced insulin secretion of pancreatic β-cells, promoted cell proliferation and protected cells from apoptosis. Further experiments using in silico prediction, luciferase reporter assay and western blot assay demonstrated that miR-185 directly targeted SOCS3 by binding to its 3'-UTR. On the contrary to miR-185's protective effects, SOCS3 significantly suppressed functions of β-cell and inactivated Stat3 pathway. When treating cells with miR-185 mimics in combination with SOCS3 overexpression plasmid, the inhibitory effects of SOCS3 were reversed. While combined treatment of miR-185 mimics and SOCS3 siRNA induced synergistically promotive effects compared to either miR-185 mimics or SOCS3 siRNA treatment alone. Moreover, we observed that miR-185 level was inversely correlated with SOCS3 expression in diabetes patients. In conclusion, this study revealed a functional and mechanistic link between miR-185 and SOCS3 in the pathogenesis of diabetes. MiR-185 plays an important role in the regulation of insulin secretion and β-cell growth in diabetes. Restoration of miR-185 expression may serve a potentially promising and efficient therapeutic approach for diabetes.

High suppressor of cytokine signaling-3 expression impairs STAT3-dependent protective effects of interleukin-22 in ulcerative colitis in remission

BACKGROUND

High SOCS3 expression in intestinal epithelial cells (IECs) of patients with ulcerative colitis (UC) in remission reflects the shorter time to relapse. We investigated whether high SOCS3 increased risk for relapse through violating STAT3-dependent protective effects of interleukin (IL)-22 during UC remission.

METHODS

Expression of IL-22 and c-Myc in UC remission mucosa was analyzed by immunohistochemistry. Effects of IL-22 on migration and proliferation of IEC cell lines with enforced SOCS3 expression were assessed with wounding assay and CCK-8 assay, respectively. Influence of STAT3 interference and SOCS3 overexpression on IL-22-regulated expression of antimicrobial peptide and proliferation-related molecules, including DMBT1, c-Myc, Survivin, Bcl-2, and Bcl-xL, were performed with quantitative real-time polymerase chain reaction or Western blot.

RESULTS

Patients with UC in remission showed significantly more IL-22-positive immune cells, but no difference of epithelial c-Myc levels, in mucosa compared with healthy controls. Overexpression of SOCS3 nearly abolished IL-22-induced activation of STAT3. By inhibiting STAT3 signaling, SOCS3 influenced IL-22-induced expression of DMBT1, c-Myc, Survivin, and Bcl-2 as well as proliferation and migration processes in cultured IEC cell line.

CONCLUSIONS

SOCS3 overexpression impairs IL-22-mediated epithelial homeostasis and mucosal wound healing, which could be the mechanism for high SOCS3 IEC expression contributed early relapse of mucosal inflammation. Prevention of SOCS3 expression or enhancement of IL-22/STAT3 signaling in IEC seems to be rational therapeutic strategies for UC remission maintenance.

[Serum levels of suppressor of cytokine signaling 3, tumor necrosis factor-alpha and interleukin-10 in preeclampsia mothers and their clinical values]

OBJECTIVE

To explore the serum levels of suppressor of cytokine signaling 3 (SOCS3), tumor necrosis factor-alpha (TNF-α) and interleukin-10 (IL-10) in preeclampsia mothers and determine their clinical values.

METHODS

A total of 40 preeclampsia mothers at International Peace Maternity and Child Health Hospital of China Welfare Institute Affiliated to Shanghai Jiaotong University from March 2011 to August 2013 were enrolled into observation group. Another 40 cases of mothers without pregnancy complications were selected as control group. Then the serum contents of SOCS3, TNF-α and IL-10 were detected and their correlations analyzed.

RESULTS

(1) The mRNA levels of SOCS3 of observation and control groups were 38 ± 6and 100 ± 16while the mRNA levels of TNF-α 226 ± 40 and 100 ± 19 respectively; (2)the proteins levels of SOCS3 of observation group were lower than those of control group (P < 0.05) while the proteins levels of TNF-α of observation group were higher than those of control group (P < 0.05); (3)the mRNA and protein contents of SOCS3 were negatively correlated with mRNA and protein contents of TNF-α and positively correlated with IL-10.

CONCLUSION

The serum content of SOCS3 decreases significantly in preeclampsia so that there is a down-regulation of Th1 type cytokine TNF-α and an up-regulation of Th2 type cytokine IL-10. And it may play an important role in the occurrence of disease.

Hepatitis C virus infection in vitro triggers endoplasmic reticulum stress and downregulates insulin receptor substrates 1 and 2 through upregulation of cytokine signaling suppressor 3

Hepatitis C virus (HCV) infection is highly prevalent worldwide and most of HCV infections enter into chronic phase subsequently leading to insulin resistance (IR) and clinical complications. Although the clinics of chronic HCV infection is well described, there is need to better understand the molecular mechanisms of HCV-induced IR. Therefore this study was aimed to unveil the role of host genes involved in the development of HCV-induced IR. For this purpose the expression of selected genes in HCV-infected and non-infected Huh-7 cells at various time post infection (p.i.) was assayed by real-time PCR. HCV infection was found to trigger endoplasmic reticulum (ER) stress response as demonstrated by an increase in the expression of calreticulin (Cal) gene but no change in the expression of Gadd153 gene. The infection also enhanced the expression of suppressor of cytokine signaling 3 (SOCS-3), responsible for the degradation of insulin receptor substrates (IRS). Moreover, it led to a decreased expression of key signaling molecules IRS-1 and IRS-2, unchanged expression of SOCS-7 and increased expression of downstream signaling molecule Akt. Altogether these findings indicate that the HCV infection induces ER stress and IR in Huh-7 cells in vitro.

Japanese encephalitis virus upregulates the expression of SOCS3 in mouse brain and Raw264.7 Cells

Japanese encephalitis virus (JEV) is one of the pathogens that can invade the central nervous system, causing acute infection and inflammation of brain. SOCS3 protein plays a vital role in immune processes and inflammation of the central nervous system. In this study, Raw264.7 cells and suckling mice were infected with JEV, and SOCS3 expression was analyzed by the gene expression profile, semiquantitative RT-PCR, qRT-PCR, immunohistochemistry (IHC) and Western blot. Results indicated that 520 genes were found to be differentially expressed (fold change ≥ 2.0, p < 0.05) in total. The differentially regulated genes were involved in biological processes, such as stimulus response, biological regulation and immune system processes. JEV early infection could induce SOCS3 expression, upregulating both the mRNA and protein levels in Raw264.7 cells in a time-dependent manner. The SOCS3 expression was much lower in Raw264.7 cells infected with inactivated JEV than wild-type JEV. In vivo, SOCS3 protein was also found to upregulate the expression of mRNA and protein in JEV-infected mouse brain. Taken together, our data showed that JEV early infection could induce the upregulation of SOCS3 expression, both in vitro and in vivo, providing the basic theoretical foundation for future research on the invasion mechanism of JEV.

Impaired interferon signaling in chronic hepatitis C patients with advanced fibrosis via the transforming growth factor beta signaling pathway

Malnutrition in the advanced fibrosis stage of chronic hepatitis C (CH-C) impairs interferon (IFN) signaling by inhibiting mammalian target of rapamycin complex 1 (mTORC1) signaling. However, the effect of profibrotic signaling on IFN signaling is not known. Here, the effect of transforming growth factor (TGF)-β signaling on IFN signaling and hepatitis C virus (HCV) replication was examined in Huh-7.5 cells by evaluating the expression of forkhead box O3A (Foxo3a), suppressor of cytokine signaling 3 (Socs3), c-Jun, activating transcription factor 2, ras homolog enriched in brain, and mTORC1. The findings were confirmed in liver tissue samples obtained from 91 patients who received pegylated-IFN and ribavirin combination therapy. TGF-β signaling was significantly up-regulated in the advanced fibrosis stage of CH-C. A significant positive correlation was observed between the expression of TGF-β2 and mothers against decapentaplegic homolog 2 (Smad2), Smad2 and Foxo3a, and Foxo3a and Socs3 in the liver of CH-C patients. In Huh-7.5 cells, TGF-β1 activated the Foxo3a promoter through an AP1 binding site; the transcription factor c-Jun was involved in this activation. Foxo3a activated the Socs3 promoter and increased HCV replication. TGF-β1 also inhibited mTORC1 and IFN signaling. Interestingly, c-Jun and TGF-β signaling was up-regulated in treatment-resistant IL28B minor genotype patients (TG/GG at rs8099917), especially in the early fibrosis stage. Branched chain amino acids or a TGF-β receptor inhibitor canceled these effects and showed an additive effect on the anti-HCV activity of direct-acting antiviral drugs (DAAs).

CONCLUSION

Blocking TGF-β signaling could potentiate the antiviral efficacy of IFN- and/ or DAA-based treatment regimens and would be useful for the treatment of difficult-to-cure CH-C patients.

Inhibition of leptin-induced vascular extracellular matrix remodelling by adiponectin

Vascular extracellular matrix (ECM) remodelling, which is the result of disruption in the balance of ECM synthesis and degradation, induces vessel fibrosis and thereby leads to hypertension. Leptin is known to promote tissue fibrosis, while adiponectin has recently been demonstrated to be anti-fibrogenic in tissue fibrosis. In this study, we aimed to evaluate the leptin-antagonist function of adiponectin and to further elucidate the mechanisms through which adiponectin dampens leptin signalling in vascular smooth muscle cells, thus preventing excess ECM production, in our already established 3D co-culture vessel models. Our 3D co-culture vessel model, which mimics true blood vessels, is composed of vascular endothelial cells, vascular smooth muscle cells and collagen type I. We validated the profibrogenic effects of leptin and analysed matrix metalloproteinase 2 (MMP2), MMP9, tissue inhibitor of metalloproteinase 1 (TIMP1) and collagen types II/IV secretion in 3D vessel models. The protective/inhibitory effects of adiponectin were re-analysed by inhibiting adiponectin receptor 1 (AdipoR) and AdipoR2 expression in endothelial cells using RNAi technology. In the 3D vessel models, adiponectin blocked the leptin-stimulated secretion of collagen types II/IV and TIMP1 while significantly increasing MMP2/9 activity. In endothelial cells, adiponectin induced phosphorylation of AMPK, thereby suppressing leptin-mediated STAT3 phosphorylation through induction of SOCS3 in smooth muscle cells. Our findings indicate that adiponectin disrupted the leptin-induced vascular ECM remodelling via AdipoR1 and enhanced AMPK signalling in endothelial cells, which, in turn, promoted SOCS3 up-regulation in smooth muscle cells to repress leptin-stimulated phosphorylation of STAT3.

Ghrelin induces leptin resistance by activation of suppressor of cytokine signaling 3 expression in male rats: implications in satiety regulation

The anorexigenic adipocyte-derived hormone leptin and the orexigenic hormone ghrelin act in opposition to regulate feeding behavior via the vagal afferent pathways. The mechanisms by which ghrelin exerts its inhibitory effects on leptin are unknown. We hypothesized that ghrelin activates the exchange protein activated by cAMP (Epac), inducing increased SOCS3 expression, which negatively affects leptin signal transduction and neuronal firing in nodose ganglia (NG) neurons. We showed that 91 ± 3% of leptin receptor (LRb) -bearing neurons contained ghrelin receptors (GHS-R1a) and that ghrelin significantly inhibited leptin-stimulated STAT3 phosphorylation in rat NG neurons. Studies of the signaling cascades used by ghrelin showed that ghrelin caused a significant increase in Epac and suppressor of cytokine signaling 3 (SOCS3) expression in cultured rat NG neurons. Transient transfection of cultured NG neurons to silence SOCS3 and Epac genes reversed the inhibitory effects of ghrelin on leptin-stimulated STAT3 phosphorylation. Patch-clamp studies and recordings of single neuronal discharges of vagal primary afferent neurons showed that ghrelin markedly inhibited leptin-stimulated neuronal firing, an action abolished by silencing SOCS3 expression in NG. Plasma ghrelin levels increased significantly during fasting. This was accompanied by enhanced SOCS3 expression in the NG and prevented by treatment with a ghrelin antagonist. Feeding studies showed that silencing SOCS3 expression in the NG reduced food intake evoked by endogenous leptin. We conclude that ghrelin exerts its inhibitory effects on leptin-stimulated neuronal firing by increasing SOCS3 expression. The SOCS3 signaling pathway plays a pivotal role in ghrelin's inhibitory effect on STAT3 phosphorylation, neuronal firing, and feeding behavior.

Dysregulation of the suppressor of cytokine signalling 3-signal transducer and activator of transcription-3 pathway in the aetiopathogenesis of Sjögren's syndrome

The suppressor of cytokine signalling 3 (SOCS3) negatively regulates the Janus kinase (JAK)/signal transducer and activator of transcription-3 (STAT-3)/interleukin (IL)-17 pathway. The proinflammatory cytokine IL-17 is over-expressed in Sjögren's syndrome (SS) and is a key factor in its pathogenesis. We hypothesized that IL-17 over-expression in SS results from ineffective regulation by SOCS3. The expression of SOCS3 was analysed in peripheral blood mononuclear cells (PBMC) from SS cases, sicca controls (SC) and healthy controls (HC) and tissue samples from SS, SC and healthy salivary glands (HSG). PBMC and salivary gland tissue from SS and controls were dual-immunostained for SOCS3 and IL-17. IL-6-stimulated PBMC from SS and controls were evaluated for time-dependent STAT-3 activation and SOCS3 induction, and for IL-17 expression. Immunoblotting revealed greater levels of SOCS3 in PBMC from SS than SC (P = 0·017) or HC (P < 0·001). Similarly, the proportion of salivary-gland tissue cells staining for SOCS3 was significantly higher in SS than SC (P = 0·029) or HSG (P = 0·021). The cells in PBMC/salivary gland samples from controls predominantly expressed either SOCS3 or IL-17. However, there was a high frequency of SOCS3/IL-17 co-expression within cells of SS samples. IL-6-stimulation of PBMC from SS cases revealed prolonged activation of STAT-3 with reduced negative regulation by SOCS3, and enhanced expression of IL-17. This study showed that SOCS3 expression is up-regulated in SS. However, the absence in SS of the normal inverse relationship between SOCS3 and pSTAT-3/IL-17 indicates a functional disturbance in this signalling cascade. Consequently, a reduction in function, rather than a reduction in expression of SOCS3 accounts for the unregulated expression of IL-17 in SS, and may play a crucial role in aetiopathogenesis.

[Activation of TNF-α and signaling pathway in the hypothalamus of the rats subjected to chronic unpredictable mild stressors after middle cerebral artery occlusion]

This study was aimed to investigate the changes of the hypothalamic-pituitary-adrenal axis (HPAA) activity and the cytokines system in the hypothalamus of the depressive rats which were exposed to chronic unpredictable mild stressors (CUMS) after middle cerebral artery occlusion (MCAO). By means of qRT-PCR, ELISA and Western blot, mRNA and/or protein expressions of corticotropin releasing factor (CRF), tumor necrosis factors-α (TNF-α), suppressor of cytokines signaling 3 (SOCS3), phosphorylation of signal transducers and activators of transcription 3 (pSTAT3) were measured in the hypothalamus of rats. The results showed that, compared with control group, CUMS+MCAO group exhibited increased mRNA levels of CRF, TNF-α, SOCS3, as well as up-regulated CRF, TNF-α, SOCS3 and pSTAT3 protein expressions. Furthermore, there were correlations between CRF and TNF-α, TNF-α and SOCS3, SOCS3 and pSTAT3, respectively. These observations indicated the CRF system was activated in the post stroke depression (PSD) status. The TNF-α and its signaling pathway, STAT3/SOCS3, were up-regulated in mRNA and protein levels. In conclusion, this study presents the evidence which supports the hypothesis of signaling cross-talk between the CRF system and TNF-α signaling pathway after ischemic stroke and CUMS.

Insulin resistance, adipokine profile and hepatic expression of SOCS-3 gene in chronic hepatitis C

AIM

To analyze adipokine concentrations, insulin resistance and hepatic expression of suppressor of cytokine signaling 3 (SOCS-3) in patients with chronic hepatitis C genotype 1 with normal body weight, glucose and lipid profile.

METHODS

The study group consisted of 31 patients with chronic hepatitis C and 9 healthy subjects. Total levels of adiponectin, leptin, resistin, visfatin, omentin, osteopontin and insulin were measured using an ELISA kit. The hepatic expression of SOCS-3 was determined by the use of the reverse transcription polymerase chain reaction method.

RESULTS

Homeostasis model assessment for insulin resistance (HOMA-IR) values were significantly higher in hepatitis C virus (HCV) infected patients without metabolic disorders compared to healthy controls (2.24 vs 0.59, P = 0.0003). Hepatic steatosis was observed in 32.2% of patients with HCV infection and was found in patients with increased HOMA-IR index (2.81 vs 1.99, P = 0.05) and reduced adiponectin level (5.96 vs 8.37, P = 0.04). Inflammatory activity (G ≥ 2) was related to increased osteopontin concentration (34.04 vs 23.35, P = 0.03). Advanced liver fibrosis (S ≥ 2) was associated with increased levels of omentin and osteopontin (436.94 vs 360.09, P = 0.03 and 32.84 vs 20.29, P = 0.03) and reduced resistin concentration (1.40 vs 1.74, P = 0.047). No correlations were reported between adipokine profile, HOMA-IR values and hepatic expression of the SOCS-3 gene.

CONCLUSION

We speculated that no relationship between adipokines and HOMA-IR values may indicate that HCV can induce insulin resistance itself. Some adipokines appear to be biochemical markers of steatosis, inflammation and fibrosis in patients with chronic HCV infection. © 2014 Baishideng Publishing Group Inc. All rights reserved.

Short communication: serum-based assay accurately detects single nucleotide polymorphisms of IL28B and SOCS3 in HIV/hepatitis C virus-coinfected subjects

Single nucleotide polymorphisms (SNPs) have become important in predicting treatment response to interferon containing anti-hepatitis C virus (HCV) therapy in HCV and HIV/HCV-infected patients. A reliable method for extracting host DNA from serum for genotyping assays would present a practical alternative for clinicians and investigators seeking to perform SNP analyses in HCV-infected patients, particularly in resource-limited settings. Human genomic DNA was extracted from peripheral blood mononuclear cells (PBMCs) and serum of 51 HIV/HCV coinfected patients using the QIAamp DNA Blood Mini Kit and QIAamp Min Elute Virus Spin Kit, respectively. Genotyping assays for the IL28B SNP (rs12979860) and SOCS3 SNP (rs4969170) were performed using the commercially available ABI Taqman allelic discrimination kit and reverse transcriptase-polymerase chain reaction (RT-PCR) was performed using 50 cycles. Results of the genotyping assays using DNA from both PBMCs and cell-free serum were determined separately and then analyzed for concurrence. Genotype analyses performed using DNA isolated from PBMCs or cell-free serum showed a 100% agreement between the IL28B genotyping results from the serum and PBMC isolates and 98% agreement for SOCS3 SNP. This novel serum-based assay to isolate DNA fragments from the serum of HIV/HCV-coinfected subjects can accurately determine a subject's genotype for IL28B (rs12979860) and SOCS3 (rs4969170). This assay could be immediately valuable for detecting clinically relevant SNPs from serum in cases in which PBMCs are not available.

SOCS3 expression correlates with severity of inflammation in mouse hepatitis virus strain 3-induced acute liver failure and HBV-ACLF

Recently, suppressor of cytokine signaling-3 (SOCS3) has been shown to be an inducible endogenous negative regulator of Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway which is relevant in inflammatory response, while its functions in acute liver failure and HBV-induced acute-on-chronic liver failure (HBV-ACLF) have not been fully elucidated. In this study, we explored the role of SOCS3 in the development of mouse hepatitis virus strain 3 (MHV-3)-induced acute liver failure and its expression in liver and peripheral blood mononuclear cells (PBMCs) of patients with HBV-ACLF. Inflammation-related gene expression was detected by real-time PCR, immunohistochemistry and Western blotting. The correlation between SOCS3 level and liver injury was studied. Our results showed that the SOCS3 expression was significantly elevated in both the liver tissue and PBMCs from patients with HBV-ACLF compared to mild chronic hepatitis B (CHB). Moreover, a time course study showed that SOCS3 level was increased remarkably in the liver of BALB/cJ mice at 72 h post-infection. Pro-inflammatory cytokines, interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, were also increased significantly at 72 h post-infection. There was a close correlation between hepatic SOCS3 level and IL-6, and the severity of liver injury defined by alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, respectively. These data suggested that SOCS3 may play a pivotal role in the pathogenesis of MHV-3-induced acute liver failure and HBV-ACLF.

Zac1 regulates astroglial differentiation of neural stem cells through Socs3

Cell-fate decisions and differentiation of embryonic and adult neural stem cells (NSC) are tightly controlled by lineage-restricted and temporal factors that interact with cell-intrinsic programs and extracellular signals through multiple regulatory loops. Imprinted genes are important players in neurodevelopment and mental health although their molecular and cellular functions remain poorly understood. Here, we show that the paternally expressed transcriptional regulator Zac1 (zinc finger protein regulating apoptosis and cell cycle arrest) is transiently induced during astroglial and neuronal differentiation of embryonic and adult NSC lines. Thereby, Zac1 transactivates Socs3 (suppressor of cytokine signaling 3), a potent inhibitor of prodifferentiative Jak/Stat3 signaling, in a lineage-specific manner to prevent precocious astroglial differentiation. In vivo, Zac1 and Socs3 colocalize in the neocortical ventricular zone during incipient astrogliogenesis. Zac1 overexpression in primary NSCs delays astroglial differentiation whereas knockdown of Zac1 or Socs3 facilitates formation of astroglial cells. This negative feedback loop is unrelated to Zac1's cell cycle arrest function and specific to the Jak/Stat3 pathway. Hence, reinstating Jak/Stat3 signaling in the presence of increased Zac1 expression allows for timely astroglial differentiation. Overall, we suggest that the imprinted gene Zac1 curtails astroglial differentiation of NSCs in the developing and adult brain.

Leptin does not induce an inflammatory response in the murine placenta

Leptin is described as a pro-inflammatory signal in fat tissue, which is released from adipocytes and in turn activates immune cells. Also, leptin levels are known to be increased in pregnancies complicated with enhanced inflammatory processes in the placenta. Hence, we assumed that increased leptin amounts might contribute to inducing an inflammatory response in the placenta. To test this hypothesis, pregnant mice were continuously infused with recombinant murine leptin s. c. from day g13 to g16, resulting in a 3-fold increase of maternal circulating serum leptin levels. Dissected placentas were examined for the expression of pro-inflammatory cytokines IL-6 and TNF-alpha and the anti-inflammatory cytokine IL-10 using qPCR analysis. No changes were found except for TNF-alpha, which was slightly elevated upon leptin stimulation. However, TNF-alpha protein levels were not significantly higher in placentas from leptin treated mice. Also, leukocyte infiltration in the labyrinth section of placentas was not increased. In summary, our data demonstrate for the first time that elevated leptin levels alone do not induce an inflammatory response in the placenta.

Expression of selected genes in liver biopsy specimens in relation to early virological response in patients with chronic hepatitis C with HCV mono- and HIV/HCV co-infection

The aim of our study was to evaluate the significance of IL-28B single-nucleotide polymorphism and hepatic expression of IFI27, SOCS3 and miR-122 in order to predict early virological response (EVR) in patients infected with HCV genotype 1 or 4. The study group consisted of 65 patients: 46 with HCV mono- and 19 with HIV/HCV co-infection. Analyses of IL-28B single-nucleotide polymorphism C/T (rs12979860) in the blood and expression of SOCS3, IFI27 and miR-122 in liver biopsy samples obtained before PegIFN and ribavirin treatment were performed by the RT-PCR method. EVR was defined as a >2log decline in HCV viremia at week 12. EVR was associated with a lower expression of IFI27 and a more frequent presence of the IL28BCC genotype. IFI27 expression was lower in patients with the CC genotype, irrespective of EVR. In multivariate logistic regression, only IL28B CC genotype and age above 40 years influenced EVR (OR =5.09 and 0.29 respectively). In contrast to IFI27, expression of miR-122 and SOCS3 in patients with different IL28B genotypes was not statistically significantly different. A correlation between miR-122 and SOCS3 was found (Rho =0.495094 p< 0.0001). Analysis of IFI27, SOCS3 and miR-122 hepatic expression does not provide substantial benefits for the prognosis of EVR. The only independent prognostic factors for EVR are age and IL28B genotype. The prognostic significance of IFI27 expression for EVR is dependent on the genetic polymorphism of IL28B.

Aspirin-triggered Lipoxin A4 attenuates mechanical allodynia in association with inhibiting spinal JAK2/STAT3 signaling in neuropathic pain in rats

Aspirin-triggered Lipoxin A4 (ATL), as a Lipoxin A4 (LXA4) epimer, is endogenously produced by aspirin-acetylated cycloxygenase-2 (COX-2) and plays a vital role in endogenous anti-inflammation via the LXA4 receptor (ALX). Recent investigations have indicated that spinal neuroinflammation and the activation of the Janus Kinase 2 (JAK2)/Signal Transducers and Transcription Activators 3 (STAT3) signaling pathway are involved in neuropathic pain states. However, the effect of ATL on neuroinflammation and JAK2/STAT3 signaling in chronic constriction injury (CCI)-induced neuropathic pain in rats has not been well-studied. The present study demonstrated the anti-inflammatory and analgesic effect of ATL on neuropathic pain and assessed the role of spinal JAK2/STAT3 signaling on the effect of ATL. Intrathecal administration of ATL significantly attenuated mechanical allodynia via spinal ALX and inhibited the upregulation of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) on day 7 of CCI surgery. In addition, ATL markedly suppressed the upregulation of p-STAT3 induced by the neuropathic pain. Blockade of JAK2-STAT3 signaling with intrathecal administration of the JAK2 inhibitor AG490 or the STAT3 inhibitor S3I-201 clearly reduced mechanical allodynia and the upregulation of pro-inflammatory cytokines in CCI rats. Interestingly, inhibition of JAK2/STAT3 signaling via ATL or the specific signaling inhibitor (AG49, S3I-201) further promoted the increased expression of suppressor of cytokine signaling 3 (SOCS3) mRNA in the spinal cord induced by CCI surgery. Taken together, our results suggested that the analgesic effect of ATL was mediated by inhibiting spinal JAK2/STAT3 signaling and hence the spinal neuroinflammation in CCI rats.

Dynamic expression of the suppressor of cytokine signaling-3 and cytokines in the cerebral basilar artery of rats with subarachnoid hemorrhage, and the effect of acetylcholine

BACKGROUND

There are complex interactions between acetylcholine (ACh), the suppressor of cytokine signaling-3 (SOCS-3), and cytokines, however, little is known about their dynamic expression or their effects on cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH). Therefore, we aimed to describe and clarify the dynamic expression of SOCS-3 and cytokines after SAH, as well as the relationships between the levels of SOCS-3, cytokines, and ACh.

METHODS

The rat model of single cisterna magna injection was used to mimic acute SAH. The degree of CVS was indicated by lumen diameter and artery wall thickness under H&E staining. A semi-quantitative immunohistochemical analysis method was used to clarify the role of SOCS-3 in the CVS after SAH. We also measured the content of IL-6 and IL-10 in cerebrospinal fluid.

RESULTS

We found that SOCS-3 expression levels increased rapidly within 12 h after SAH, more slowly after 12 h, and did not reach a peak within 48 h. Interleukin 6 (IL-6) levels rapidly increased within 24 h after SAH, reached a peak 24 h after SAH, and decreased slightly at 48 h. IL-10 levels increased during the first 6 h after SAH, after which this increase tapered off. ACh treatment reduced IL-6 levels and resulted in elevated levels of SOCS-3, but had no effect on IL-10 expression. Furthermore, ACh treatment relieved basilar arterial vasospasm, whereas mecamylamine pretreatment counteracted the activity of ACh.

CONCLUSIONS

Taken together, these data indicate that SOCS-3 was involved in vasospasm via an IL-6- and IL-10-related mechanism, and that CVS following SAH could be reversed by the intraventricular injection of ACh.

Phosphorylated STAT3 and PD-1 regulate IL-17 production and IL-23 receptor expression in Mycobacterium tuberculosis infection

We studied the factors that regulate IL-23 receptor expression and IL-17 production in human tuberculosis infection. Mycobacterium tuberculosis (M. tb)-stimulated CD4(+) T cells from tuberculosis patients secreted less IL-17 than did CD4(+) T cells from healthy tuberculin reactors (PPD(+) ). M. tb-cultured monocytes from tuberculosis patients and PPD(+) donors expressed equal amounts of IL-23p19 mRNA and protein, suggesting that reduced IL-23 production is not responsible for decreased IL-17 production by tuberculosis patients. Freshly isolated and M. tb-stimulated CD4(+) T cells from tuberculosis patients had reduced IL-23 receptor and phosphorylated STAT3 (pSTAT3) expression, compared with cells from PPD(+) donors. STAT3 siRNA reduced IL-23 receptor expression and IL-17 production by CD4(+) T cells from PPD(+) donors. Tuberculosis patients had increased numbers of PD-1(+) T cells compared with healthy PPD(+) individuals. Anti-PD-1 antibody enhanced pSTAT3 and IL-23R expression and IL-17 production by M. tb-cultured CD4(+) T cells of tuberculosis patients. Anti-tuberculosis therapy decreased PD-1 expression, increased IL-17 and IFN-γ production and pSTAT3 and IL-23R expression. These findings demonstrate that increased PD-1 expression and decreased pSTAT3 expression reduce IL-23 receptor expression and IL-17 production by CD4(+) T cells of tuberculosis patients.