SOCS2 expression in hematopoietic and non-hematopoietic cells during Trypanosoma cruzi infection: Correlation with immune response and cardiac dysfunction.

Chagas disease has a complex pathogenesis wherein the host immune response is essential for controlling its development. Suppressor of cytokine signaling(SOCS)2 is a crucial protein that regulates cytokine production. In this study, SOCS2 deficiency resulted in an initial imbalance of IL12- and IL-10-producing neutrophils and dendritic cells (DCs), which caused a long-lasting impact reducing inflammatory neutrophils and DCs, and tolerogenic DCs at the peak of acute disease. A reduced number of inflammatory and pro-resolving macrophages, and IL17A-producing CD4+ T cells, and increased lymphocyte apoptosis was found in SOCS2-deficient mice. Electrocardiogram analysis of chimeric mice showed that WT mice that received SOCS2 KO bone marrow transplantation presented increased heart dysfunction. Taken together, the results demonstrated that SOCS2 is a crucial regulator of the immune response during Trypanosoma cruzi infection, and suggest that a SOCS2 genetic polymorphism, or failure of its expression, may increase the susceptibility of cardiomyopathy development in Chagasic patients.

Targeting a cytokine checkpoint enhances the fitness of armored cord blood CAR-NK cells.

Immune checkpoint therapy has resulted in remarkable improvements in the outcome for certain cancers. To broaden the clinical impact of checkpoint targeting, we devised a strategy that couples targeting of the cytokine-inducible Src homology 2-containing (CIS) protein, a key negative regulator of interleukin 15 (IL-15) signaling, with fourth-generation "armored" chimeric antigen receptor (CAR) engineering of cord blood-derived natural killer (NK) cells. This combined strategy boosted NK cell effector function through enhancing the Akt/mTORC1 axis and c-MYC signaling, resulting in increased aerobic glycolysis. When tested in a lymphoma mouse model, this combined approach improved NK cell antitumor activity more than either alteration alone, eradicating lymphoma xenografts without signs of any measurable toxicity. We conclude that targeting a cytokine checkpoint further enhances the antitumor activity of IL-15-secreting armored CAR-NK cells by promoting their metabolic fitness and antitumor activity. This combined approach represents a promising milestone in the development of the next generation of NK cells for cancer immunotherapy.

Anti-inflammatory mechanisms of suppressors of cytokine signaling target ROS via NRF-2/thioredoxin induction and inflammasome activation in macrophages.

Suppressors of cytokine signaling (SOCS) exhibit diverse antiinflammatory effects. Since ROS acts as a critical mediator of inflammation, we have investigated the anti-inflammatory mechanisms of SOCS via ROS regulation in monocytic/macrophagic cells. Using PMA-differentiated monocytic cell lines and primary BMDMs transduced with SOCS1 or shSOCS1, the LPS/TLR4-induced inflammatory signaling was investigated by analyzing the levels of intracellular ROS, antioxidant factors, inflammasome activation, and pro-inflammatory cytokines. The levels of LPS-induced ROS and the production of pro-inflammatory cytokines were notably down-regulated by SOCS1 and up-regulated by shSOCS1 in an NAC-sensitive manner. SOCS1 up-regulated an ROS-scavenging protein, thioredoxin, via enhanced expression and binding of NRF-2 to the thioredoxin promoter. SOCS3 exhibited similar effects on NRF-2/thioredoxin induction, and ROS downregulation, resulting in the suppression of inflammatory cytokines. Notably thioredoxin ablation promoted NLRP3 inflammasome activation and restored the SOCS1-mediated inhibition of ROS and cytokine synthesis induced by LPS. The results demonstrate that the anti-inflammatory mechanisms of SOCS1 and SOCS3 in macrophages are mediated via NRF-2-mediated thioredoxin upregulation resulting in the downregulation of ROS signal. Thus, our study supports the anti-oxidant role of SOCS1 and SOCS3 in the exquisite regulation of macrophage activation under oxidative stress. [BMB Reports 2020; 53(12): 640-645].

SOCS2 affects the proliferation, migration and invasion of nasopharyngeal carcinoma cells via regulating EphA1.

Although the incidence of nasopharyngeal carcinoma (NPC) is relatively low, the mortality is very high and the patients have a poor prognosis. Thus, it is urgent to find a novel biomarker and a new therapeutic strategy. Suppressor of cytokine signaling-2 (SOCS2) was reported to be associated with various malignancies. However, the exact role of SOCS2 in NPC still remains largely unsure. In the present study, we showed that the expression of SOCS2 was significantly upregulated in NPC patients and cells. And the high expression of SOCS2 predicted a worse outcome in NPC patients. Moreover, the in vivo experiments indicated that knockout of SOCS2 inhibits the proliferation, migration, and invasion of NPC cells. Besides, we found a positive relationship between SOCS2 and EphA1 in NPC tissues. The rescue experiments indicated that SOCS2 affected the malignancy of NPC cells by regulating the expression of EphA1. Altogether, our data uncovered the ontogenetic role of SOCS2 dysregulation during the tumorigenesis of NPC. SOCS2 might serve as a biomarker during the diagnosis and treatment of NPC. And targeting SOCS2 might provide a novel treatment strategy for NPC patients.

SPSB1 enhances ovarian cancer cell survival by destabilizing p21.

SPRY domain-containing SOCS box protein 1 (SPSB1) is an E3 ligase adaptor protein with unknown functions in cancer cells. In this study, we found that SPSB1 knockdown markedly decreased the viability and migration of ovarian cancer cells, while ectopic SPSB1 overexpression in IL-3-dependent Ba/F3 cells significantly increased their proliferation rate compared with empty vector-transfected cells. SPSB1 knockdown significantly elevated p21 protein and mRNA levels and induced apoptosis in ovarian cancer cells, as evidenced by increased levels of cleaved PARP and decreased levels of Bcl-2. Notably, mechanistic investigations revealed that SPSB1 accelerated p21 destabilization by directly interacting with p21 and promoting its ubiquitin-mediated proteasomal degradation. Taken together, our findings provide novel insights into the role of SPSB1 in ovarian cancer cells.

A designed cell-penetrating human SOCS2 protein suppresses GH-dependent cancer cell proliferation.

Suppressor of cytokine signaling (SOCS) 2, a negative regulator of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), which is associated with acromegaly and cancers, is a promising candidate molecule for treating various diseases. To facilitate its use in protein therapy, we designed and constructed a human SOCS2 protein containing a membrane-permeable peptide sequence and expressed it in an Escherichia coli system. The partially purified recombinant protein was effectively delivered into several cancer cell lines and inhibited cell growth. Biochemical analysis showed that the recombinant SOCS2 protein interacted with growth hormone receptor (GHR) and downregulated GH-STAT5 signaling target genes. Our results suggest that the designed cell-penetrating SOCS2 protein will be useful in intercellular protein therapy to cure cancers. Abbreviations: SOCS: suppressor of cytokine signaling; GH: growth hormone; GHR: growth hormone receptor; IGF-1: insulin-like growth factor 1; CP: cell-penetrating; STAT: signal transducer and activator of transcription; JAK: Janus kinase; HNF: hepatocyte nuclear factor; MTM: membrane-translocating motif; HIV: human immunodeficiency virus.

Natural killer cells and anti-tumor immunity.

Immune checkpoint inhibitors harness the power of the immune system to fight cancer. The clinical success achieved with antibodies against the inhibitory T cell receptors PD-1 and CTLA4 has focused attention on the possibility of manipulating other immune cells, in particular those involved in innate immunity. Here we review the role of innate lymphoid cells (ILCs) and their contribution to tumor immunity. As the prototypical ILC, the natural killer (NK) cell has an intrinsic ability to detect and kill cancer cells. NK cells are dependent on the cytokine interleukin (IL)-15 for their development and effector activity. We discuss the role of the Suppressor of cytokine (SOCS) proteins in negatively regulating IL-15 and NK cell responses and the potential for targeting these small intracellular regulators as new immune checkpoints.

MicroRNA-194 Promotes Prostate Cancer Metastasis by Inhibiting SOCS2.

Serum levels of miR-194 have been reported to predict prostate cancer recurrence after surgery, but its functional contributions to this disease have not been studied. Herein, it is demonstrated that miR-194 is a driver of prostate cancer metastasis. Prostate tissue levels of miR-194 were associated with disease aggressiveness and poor outcome. Ectopic delivery of miR-194 stimulated migration, invasion, and epithelial-mesenchymal transition in human prostate cancer cell lines, and stable overexpression of miR-194 enhanced metastasis of intravenous and intraprostatic tumor xenografts. Conversely, inhibition of miR-194 activity suppressed the invasive capacity of prostate cancer cell lines in vitro and in vivo Mechanistic investigations identified the ubiquitin ligase suppressor of cytokine signaling 2 (SOCS2) as a direct, biologically relevant target of miR-194 in prostate cancer. Low levels of SOCS2 correlated strongly with disease recurrence and metastasis in clinical specimens. SOCS2 downregulation recapitulated miR-194-driven metastatic phenotypes, whereas overexpression of a nontargetable SOCS2 reduced miR-194-stimulated invasion. Targeting of SOCS2 by miR-194 resulted in derepression of the oncogenic kinases FLT3 and JAK2, leading to enhanced ERK and STAT3 signaling. Pharmacologic inhibition of ERK and JAK/STAT pathways reversed miR-194-driven phenotypes. The GATA2 transcription factor was identified as an upstream regulator of miR-194, consistent with a strong concordance between GATA2 and miR-194 levels in clinical specimens. Overall, these results offer new insights into the molecular mechanisms of metastatic progression in prostate cancer. Cancer Res; 77(4); 1021-34. ©2016 AACR.

FTO Plays an Oncogenic Role in Acute Myeloid Leukemia as a N6-Methyladenosine RNA Demethylase.

N6-Methyladenosine (m6A) represents the most prevalent internal modification in mammalian mRNAs. Despite its functional importance in various fundamental bioprocesses, the studies of m6A in cancer have been limited. Here we show that FTO, as an m6A demethylase, plays a critical oncogenic role in acute myeloid leukemia (AML). FTO is highly expressed in AMLs with t(11q23)/MLL rearrangements, t(15;17)/PML-RARA, FLT3-ITD, and/or NPM1 mutations. FTO enhances leukemic oncogene-mediated cell transformation and leukemogenesis, and inhibits all-trans-retinoic acid (ATRA)-induced AML cell differentiation, through regulating expression of targets such as ASB2 and RARA by reducing m6A levels in these mRNA transcripts. Collectively, our study demonstrates the functional importance of the m6A methylation and the corresponding proteins in cancer, and provides profound insights into leukemogenesis and drug response.

Working your SOCS off: The role of ASB10 and protein degradation pathways in glaucoma.

Evidence is accumulating to suggest that mutations in the Ankyrin and SOCS Box-containing protein-10 (ASB10) gene are associated with glaucoma. Since its identification in a large Oregon family with primary open-angle glaucoma (POAG), ASB10 variants have been associated with disease in US, German and Pakistani cohorts. ASB10 is a member of the ASB family of proteins, which have a common structure including a unique N-terminus, a variable number of central ankyrin (ANK) repeat domains and a suppressor of cytokine signaling (SOCS) box at the C-terminus. Mutations in ASB10 are distributed throughout the entire length of the gene including the two alternatively spliced variants of exon 1. A homozygous mutation in a Pakistani individual with POAG, which lies in the center of the SOCS box, is associated with a particularly severe form of the disease. Like other SOCS box-containing proteins, ASB10 functions in ubiquitin-mediated degradation pathways. The ANK repeats bind to proteins destined for degradation. The SOCS box recruits ubiquitin ligase proteins to form a complex to transfer ubiquitin to a substrate bound to the ANK repeats. The ubiquitin-tagged protein then enters either the proteasomal degradation pathway or the autophagic-lysosomal pathway. The choice of pathway appears to be dependent on which lysine residues are used to build polyubiquitin chains. However, these reciprocal pathways work in tandem to degrade proteins because inhibition of one pathway increases degradation via the other pathway. In this publication, we will review the literature that supports identification of ASB10 as a glaucoma-associated gene and the current knowledge of the function of the ASB10 protein. In addition, we present new data that indicates ASB10 expression is up-regulated by the inflammatory cytokines tumor necrosis factor-α and interleukin-1α. Finally, we will describe the emerging role of other SOCS box-containing proteins in protein degradation pathways in ocular cells.

Role of the suppressor of cytokine signaling 2 (SOCS2) during meningoencephalitis caused by Bovine herpesvirus 5 (BoHV-5).

The role of suppressors of cytokine signaling (SOCS) in meningoencephalitis caused by Bovine herpesvirus 5 (BoHV-5) was evaluated by intracranial infection in C57BL/6 wild-type mice (WT) and SOCS2 deficient mice (SOCS2(-/-)). Both infected groups presented weight loss, ruffled fur and hunched posture. Additionally, infected SOCS2(-/-) mice showed swollen chamfer and progressive depression. Infected WT animals developed mild meningitis, characterized by infiltration of mononuclear cells. Moreover, viral DNA was detected in liver and lung from infected WT group. This group also showed elevated brain levels of IFN-γ, IL-10, CXCL1 and CCL5, when compared with non-infected WT animals. Brain inflammation was exacerbated in infected SOCS2(-/-) mice with widespread distribution of the virus and increased brain levels of TNF-α, IFN-γ, IL-10, IL-12, CXCL1 and CCL5, when compared with WT infected mice. Moreover, infected SOCS2 deficient mice exhibited reduced brain mRNA expression of IFNα and IFNß and increased expression of mRNA of SOCS1, compared with infected WT mice. Taken together, our study provides an insight into the role of SOCS2 in modulating the immune response to BoHV-5 infection.

SOCS2: physiological and pathological functions.

Suppressors of cytokine signalling (SOCS) proteins are modulators of cytokine and growth factor signalling whose aberrant regulation has been linked to a variety of inflammatory and neoplastic diseases. SOCS proteins are able to act as substrate-recruiting component of E3-ubiquitin ligase complexes and target interacting proteins for degradation. At least some of the family members can also directly inhibit tyrosine kinases such as Janus Kinases (JAK). The most studied family members, CIS, SOCS1, SOCS2 and SOCS3 are important regulators of the JAK-STAT pathway. Here, we focus on SOCS2 and review its biological function as well as its implication in pathological processes. Furthermore, we take advantage of the known crystal structures of SOCS2 to discuss the potential effects of a selection of SOCS2 mutations that were identified in tumour tissues.

Interleukin-23 Facilitates Thyroid Cancer Cell Migration and Invasion by Inhibiting SOCS4 Expression via MicroRNA-25.

Interleukin-23 (IL-23) is a conventional proinflammatory cytokine that plays a role in tumor progression by inducing inflammation in the tumor microenvironment. However, the role of IL-23 in thyroid cancer migration and invasion remains unclear. In the present study, we observed that the treatment with IL-23, induced migration and invasion in human thyroid cancer cells. Additional data demonstrate that SOCS4 negatively regulates IL-23-mediated migration and invasion. On investigating the mechanisms involved in IL-23 mediated migration and invasion, we observed that miR-25 promotes the migration and invasion of thyroid cancer cells by directly binding to the 3'-UTR of SOCS4 that leads to the inhibition of SOCS4. In addition, we also demonstrated that IL-23 increases miR-25 expression levels, and overexpressed miR-25 is involved in IL-23-associated SOCS4 inhibition and cell migration and invasion. Together, our data suggest that IL-23 induces migration and invasion in thyroid cancer cells by mediating the miR-25/SOCS4 signaling pathway.

Role of SOCS3 in the Jak/stat3 pathway in the human placenta: different mechanisms for preterm and term labor.

INTRODUCTION: To identify changes in interleukin (IL)-6 levels and its pathway (Jak/stat3) in the human placenta during preterm and term labor, placental tissues were collected from primiparous women who underwent vaginal deliveries or cesarean sections in our hospital. The women were divided into three groups: preterm labor (n = 15), term labor (n = 15), and term not in labor (n = 15). MATERIAL AND METHODS: IL-6 levels were detected by ELISA in placental supernatant, and p-STAT3 and SOCS3 protein was detected by Western blot. TUNEL was used to detect apoptosis in trophoblasts. HTR-8/SVneo cells were cultured after stimulation with IL-6, and we measured p-STAT3, SOCS3, and the rate of apoptosis. RESULTS: Expression of p-STAT3 and SOCS3 in the placenta and trophoblast cells showed that IL-6 levels were highest in the preterm labor group and lowest in the term not in labor group. The highest expression of placental SOCS3 protein was observed in the preterm labor group. More apoptotic cells were found in the preterm labor group than in the other two groups by TUNEL. SOCS3 and p-STAT3 expression was significantly upregulated after stimulation by IL-6 in trophoblast cells in a dose-dependent manner. However, p-STAT3 was significantly decreased after 50 ng/mL and 100 ng/mL IL-6 for 72 h. A significant increase of apoptosis was observed with treatment of 50 ng/mL IL-6 in HTR-8/SVneo cells. CONCLUSIONS: The role of the SOCS3 protein in the Jak/stat3 pathway is to mediate different mechanisms for preterm and term labor processes in the placenta.

Suppressors of cytokine signaling 3 is essential for FcγR-mediated inflammatory response via enhancing CCAAT/enhancer-binding protein δ transcriptional activity in macrophages.

Compelling evidence indicates that suppressor of cytokine signaling 3 (SOCS3) plays a pivotal regulatory role in inflammation. However, the function of SOCS3 in inflammatory responses mediated by Fcγ receptor (FcγR) remains largely unknown. In the current study, we found that SOCS3 expression was greatly enhanced in peritoneal macrophages treated with IgG immune complex (IgG IC). By over-expressing SOCS3 in macrophages, we observed that SOCS3 promoted IgG immune complex-induced production of inflammatory mediators, including IL-6, TNF-α, MIP-2, and MIP-1α. In contrast, SOCS3-defective peritoneal macrophages generated less inflammatory cytokines and chemokines when compared with their wild type counterparts during IgG IC-induced inflammatory responses. We further demonstrated that CCAAT/enhancer-binding protein (C/EBP) δ transcription factor was the major downstream target of SOCS3 in macrophages. These data suggested that SOCS3 was an inflammatory enhancer in IgG IC-treated macrophages by increasing C/EBPδ activity. To elucidate the role for myeloid-derived SOCS3 in IgG IC-induced inflammation in vivo, LysM-cre SOCS3(fl/fl) mice lacking SOCS3 in macrophages and neutrophils were generated. We found that SOCS3 deficiency greatly alleviated IgG IC-induced generation of pro-inflammatory mediators in lungs, consistent with the in vitro data. Our current findings may provide a new theoretical basis for designing drugs for treatment of IgG IC-associated diseases.

Suppressor of cytokine signaling 1-modulated metalloproteinases and tissue inhibitor of metalloproteinase in pulmonary fibrosis.

An imbalance between metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) affects the synthesis and degradation of extracellular matrix molecules, which have an important role in the pathogenesis of pulmonary fibrosis. Lower mRNA expression levels of suppressor of cytokine signaling 1 (SOCS1) are present in fibroblasts from the lungs of pulmonary fibrosis. However, little is currently known regarding the precise role of SOCS1 has in idiopathic pulmonary fibrosis (IPF). The present study examined the expression levels of MMPs and TIMPs in A549 human epithelial lung carcinoma cells and human embryonic lung fibroblasts (HLFs) stimulated with transforming growth factor­ß1 (TGF­ß1) in conditions of deficiency and over­expression of SOCS1, by transfection with a lentivirus. Overexpression of SOCS1 in A549 cells and HLFs significantly inhibited the mRNA expression levels of MMP­1, MMP­2 and MMP­9 (P<0.05). In the A549 cells lacking SOCS1 expression, the mRNA expression levels of TIMP­1 were significantly higher compared with the control groups (P<0.01). Overexpression of SOCS1 partially reversed these changes. The expression levels of TIMP­1 in the HLFs with an overexpression of SOCS1 were decreased, as compared with the SOCS1­deficient HLFs following TGF­ß1 stimulation; however, this finding was not significant (0.24±0.01 vs. 0.53±0.02, P>0.05). The expression levels of TIMP­2 were significantly lower in the cells overexpressing SOCS1. Conversely, the mRNA expression levels of TIMP­2 were significantly higher in the SOCS1­deficient A549 cells, as compared with all of the other groups (P<0.05). TIMP­4 expression levels were elevated in the A549 cells and HLFs transfected with the SOCS1­deficient lentivirus. The expression levels of TIMP­4 were significantly lower in the groups overexpressing SOCS1, as compared with the other groups. These results suggest that SOCS1 may act as a suppressor of pulmonary fibrosis, by reducing the expression of MMPs and TIMPs. Therefore, SOCS1 may be a target for IPF treatment.

MicroRNA-155 Exerts Cell-Specific Antiangiogenic but Proarteriogenic Effects During Adaptive Neovascularization.

BACKGROUND: Adaptive neovascularization after arterial occlusion is an important compensatory mechanism in cardiovascular disease and includes both the remodeling of pre-existing vessels to collateral arteries (arteriogenesis) and angiogenic capillary growth. We now aimed to identify regulatory microRNAs involved in the modulation of neovascularization after femoral artery occlusion in mice. METHODS AND RESULTS: Using microRNA-transcriptome analysis, we identified miR-155 as a downregulated microRNA during hindlimb ischemia. Correspondingly, inhibition of miR-155 in endothelial cells had a stimulatory effect on proliferation and angiogenic tube formation via derepression of its direct target gene angiotensin II type 1 receptor. Surprisingly, miR-155-deficient mice showed an unexpected phenotype in vivo, with a strong reduction of blood flow recovery after femoral artery ligation (arteriogenesis) dependent on the attenuation of leukocyte-endothelial interaction and a reduction of proarteriogenic cytokine expression. Consistently, miR-155-deficient macrophages exhibit a specific alteration of the proarteriogenic cytokine expression profile, which is partly mediated by the direct miR-155 target gene SOCS-1. CONCLUSIONS: Our data demonstrate that miR-155 exerts an antiangiogenic but proarteriogenic function in the regulation of neovascularization via the suppression of divergent cell-specific target genes and that its expression in both endothelial and bone marrow-derived cells is essential for arteriogenesis in response to hindlimb ischemia in mice.

Calpastatin counteracts pathological angiogenesis by inhibiting suppressor of cytokine signaling 3 degradation in vascular endothelial cells.

RATIONALE: Janus kinase/signal transducer and activator of transcription (JAK/STAT) signals and their endogenous inhibitor, suppressor of cytokine signaling 3 (SOCS3), in vascular endothelial cells (ECs) reportedly dominate the pathological angiogenesis. However, how these inflammatory signals are potentiated during pathological angiogenesis has not been fully elucidated. We suspected that an intracellular protease calpain, which composes the multifunctional proteolytic systems together with its endogenous inhibitor calpastatin (CAST), contributes to the JAK/STAT regulations. OBJECTIVE: To specify the effect of EC calpain/CAST systems on JAK/STAT signals and their relationship with pathological angiogenesis. METHODS AND RESULTS: The loss of CAST, which is ensured by several growth factor classes, was detectable in neovessels in murine allograft tumors, some human malignant tissues, and oxygen-induced retinopathy lesions in mice. EC-specific transgenic introduction of CAST caused downregulation of JAK/STAT signals, upregulation of SOCS3 expression, and depletion of vascular endothelial growth factor (VEGF)-C, thereby counteracting unstable pathological neovessels and disease progression in tumors and oxygen-induced retinopathy lesions in mice. Neutralizing antibody against VEGF-C ameliorated pathological angiogenesis in oxygen-induced retinopathy lesions. Small interfering RNA-based silencing of endogenous CAST in cultured ECs facilitated µ-calpain-induced proteolytic degradation of SOCS3, leading to VEGF-C production through amplified interleukin-6-driven STAT3 signals. Interleukin-6-induced angiogenic tube formation in cultured ECs was accelerated by CAST silencing, which is suppressible by pharmacological inhibition of JAK/STAT signals, antibody-based blockage of VEGF-C, and transfection of calpain-resistant SOCS3, whereas transfection of wild-type SOCS3 exhibited modest angiostatic effects. CONCLUSIONS: Loss of CAST in angiogenic ECs facilitates µ-calpain-induced SOCS3 degradation, which amplifies pathological angiogenesis through interleukin-6/STAT3/VEGF-C axis.

Expression of suppressor of cytokine signaling 1 (SOCS1) impairs viral clearance and exacerbates lung injury during influenza infection.

Suppressor of cytokine signaling (SOCS) proteins are inducible feedback inhibitors of cytokine signaling. SOCS1-/- mice die within three weeks postnatally due to IFN-γ-induced hyperinflammation. Since it is well established that IFN-γ is dispensable for protection against influenza infection, we generated SOCS1-/-IFN-γ-/- mice to determine whether SOCS1 regulates antiviral immunity in vivo. Here we show that SOCS1-/-IFN-γ-/- mice exhibited significantly enhanced resistance to influenza infection, as evidenced by improved viral clearance, attenuated acute lung damage, and consequently increased survival rates compared to either IFN-γ-/- or WT animals. Enhanced viral clearance in SOCS1-/-IFN-γ-/- mice coincided with a rapid onset of adaptive immune responses during acute infection, while their reduced lung injury was associated with decreased inflammatory cell infiltration at the resolution phase of infection. We further determined the contribution of SOCS1-deficient T cells to antiviral immunity. Anti-CD4 antibody treatment of SOCS1-/-IFN-γ-/- mice had no significant effect on their enhanced resistance to influenza infection, while CD8+ splenocytes from SOCS1-/-IFN-γ-/- mice were sufficient to rescue RAG1-/- animals from an otherwise lethal infection. Surprisingly, despite their markedly reduced viral burdens, RAG1-/- mice reconstituted with SOCS1-/-IFN-γ-/- adaptive immune cells failed to ameliorate influenza-induced lung injury. In conclusion, in the absence of IFN-γ, the cytoplasmic protein SOCS1 not only inhibits adaptive antiviral immune responses but also exacerbates inflammatory lung damage. Importantly, these detrimental effects of SOCS1 are conveyed through discrete cell populations. Specifically, while SOCS1 expression in adaptive immune cells is sufficient to inhibit antiviral immunity, SOCS1 in innate/stromal cells is responsible for aggravated lung injury.

SOCS genes expression during physiological and perturbed implantation in bovine endometrium.

In mammals, suppressor of cytokine signalling (CISH, SOCS1 to SOCS7) factors control signalling pathways involved in the regulation of numerous physiological processes including pregnancy. In order to gain new insights into the biological functions of SOCS in the endometrium, a comprehensive analysis of SOCS gene expression was carried out in bovine caruncular (CAR) and intercaruncular (ICAR) tissues collected i) during the oestrous cycle, ii) at the time of maternal recognition of pregnancy and at implantation in inseminated females, iii) following uterine interferon-tau (IFNT) infusion at day 14 post-oestrus, iv) following a period of controlled intravaginal progesterone release and v) following transfer of embryos by somatic-cell nuclear transfer (SCNT). The regulatory effects of IFNT on in vitro cultured epithelial and stromal cells were also examined. Altogether, our data showed that CISH, SOCS4, SOCS5 and SOCS7 mRNA levels were poorly affected during luteolysis and pregnancy. In contrast, SOCS1, SOCS2, SOCS3 and SOCS6 mRNA levels were strongly up-regulated at implantation (day 20 of pregnancy). Experimental in vitro and in vivo models demonstrated that only CISH, SOCS1, SOCS2 and SOCS3 were IFNT-induced genes. Immunohistochemistry showed an intense SOCS3 and SOCS6 staining in the nucleus of luminal and glandular epithelium and of stromal cells of pregnant endometrium. Finally, SOCS3 expression was significantly increased in SCNT pregnancies in keeping with the altered immune function previously reported in this model of compromised implantation. Collectively, our data suggest that spatio-temporal changes in endometrial SOCS gene expression reflect the acquisition of receptivity, maternal recognition of pregnancy and implantation.