Suppressor of cytokine signaling 3 (SOCS3) in Th2 cells evokes Th2 cytokines, IgE, and eosinophilia

Epithelium-derived kallistatin promotes CD4+ T-cell chemotaxis to TH2-type inflammation in chronic rhinosinusitis

BACKGROUND

The function of kallistatin in airway inflammation, particularly chronic rhinosinusitis with nasal polyps (CRSwNP), has not been elucidated.

OBJECTIVE

We sought to investigate the role of kallistatin in airway inflammation.

METHODS

Kallistatin and proinflammatory cytokine expression levels were detected in nasal polyps. For the in vivo studies, we constructed the kallistatin-overexpressing transgenic mice to elucidate the role of kallistatin in airway inflammation. Furthermore, the levels of plasma IgE and proinflammatory cytokines in the airways were evaluated in the kallistatin-/- rat in vivo model under a type 2 inflammatory background. Finally, the Notch signaling pathway was explored to understand the role of kallistatin in CRSwNP.

RESULTS

We showed that the expression of kallistatin was significantly higher in nasal polyps than in the normal nasal mucosa and correlated with IL-4 expression. We also discovered that the nasal mucosa of kallistatin-overexpressing transgenic mice expressed higher levels of IL-4 expression, associating to TH2-type inflammation. Interestingly, we observed lower IL-4 levels in the nasal mucosa and lower total plasma IgE of the kallistatin-/- group treated with house dust mite allergen compared with the wild-type house dust mite group. Finally, we observed a significant increase in the expression of Jagged2 in the nasal epithelium cells transduced with adenovirus-kallistatin. This heightened expression correlated with increased secretion of IL-4, attributed to the augmented population of CD4+CD45+Notch1+ T cells. These findings collectively may contribute to the induction of TH2-type inflammation.

CONCLUSIONS

Kallistatin was demonstrated to be involved in the CRSwNP pathogenesis by enhancing the TH2 inflammation, which was found to be associated with more expression of IL-4, potentially facilitated through Jagged2-Notch1 signaling in CD4+ T cells.

SOCS1 and SOCS3 as key checkpoint molecules in the immune responses associated to skin inflammation and malignant transformation

SOCS are a family of negative inhibitors of the molecular cascades induced by cytokines, growth factors and hormones. At molecular level, SOCS proteins inhibit the kinase activity of specific sets of receptor-associated Janus Activated Kinases (JAKs), thereby suppressing the propagation of intracellular signals. Of the eight known members, SOCS1 and SOCS3 inhibit activity of JAKs mainly induced by cytokines and can play key roles in regulation of inflammatory and immune responses. SOCS1 and SOCS3 are the most well-characterized SOCS members in skin inflammatory diseases, where their inhibitory activity on cytokine activated JAKs and consequent anti-inflammatory action has been widely investigated in epidermal keratinocytes. Structurally, SOCS1 and SOCS3 share the presence of a N-terminal domain containing a kinase inhibitory region (KIR) motif able to act as a pseudo-substrate for JAK and to inhibit its activity. During the last decades, the design and employment of SOCS1 and SOCS3-derived peptides mimicking KIR domains in experimental models of dermatoses definitively established a strong anti-inflammatory and ameliorative impact of JAK inhibition on skin inflammatory responses. Herein, we discuss the importance of the findings collected in the past on SOCS1 and SOCS3 function in the inflammatory responses associated to skin immune-mediated diseases and malignancies, for the development of the JAK inhibitor drugs. Among them, different JAK inhibitors have been introduced in the clinical practice for treatment of atopic dermatitis and psoriasis, and others are being investigated for skin diseases like alopecia areata and vitiligo.

The Interplay Between Helicobacter pylori and Suppressors of Cytokine Signaling (SOCS) Molecules in the Development of Gastric Cancer and Induction of Immune Response

Helicobacter pylori (H. pylori) colonizes the stomach and leads to the secretion of a vast range of cytokines by infiltrated leukocytes directing immune/inflammatory response against the bacterium. To regulate immune/inflammatory responses, suppressors of cytokine signaling (SOCS) proteins bind to multiple signaling components located downstream of cytokine receptors, such as Janus kinase (JAK), signal transducers and activators of transcription (STAT). Dysfunctional SOCS proteins in immune cells may facilitate the immune evasion of H. pylori, allowing the bacteria to induce chronic inflammation. Dysregulation of SOCS expression and function can contribute to the sustained H. pylori-mediated gastric inflammation which can lead to gastric cancer (GC) development. Among SOCS molecules, dysregulated expression of SOCS1, SOCS2, SOCS3, and SOCS6 were indicated in H. pylori-infected individuals as well as in GC tissues and cells. H. pylori-induced SOCS1, SOCS2, SOCS3, and SOCS6 dysregulation can contribute to the GC development. The expression of SOCS molecules can be influenced by various factors, such as epigenetic DNA methylation, noncoding RNAs, and gene polymorphisms. Modulation of the expression of SOCS molecules in gastric epithelial cells and immune cells can be considered to control gastric carcinogenesis as well as regulate antitumor immune responses, respectively. This review aimed to explain the interplay between H. pylori and SOCS molecules in GC development and immune response induction as well as to provide insights regarding potential therapeutic strategies modulating SOCS molecules.

Aberrant expression of suppressor of cytokine signaling (SOCS) molecules contributes to the development of allergic diseases

Suppressor of cytokine signalling (SOCS) proteins bind to certain cytokine receptors, Janus kinases and signalling molecules to regulate signalling pathways, thus controlling immune and inflammatory responses. Dysregulated expression of various types of SOCS molecules was indicated in multiple types of allergic diseases. SOCS1, SOCS2, SOCS3, SOCS5, and cytokine-inducible SH2 domain protein (CISH) can differentially exert anti-allergic impacts through different mechanisms, such as suppressing Th2 cell development and activation, reducing eosinophilia, decreasing IgE production, repressing production of pro-allergic chemokines, promoting Treg cell differentiation and activation, suppressing Th17 cell differentiation and activation, increasing anti-allergic Th1 responses, inhibiting M2 macrophage polarization, modulating survival and development of mast cells, reducing pro-allergic activity of keratinocytes, and suppressing pulmonary fibrosis. Although some anti-allergic effects were attributed to SOCS3, it can perform pro-allergic impacts through several pathways, such as promoting Th2 cell development and activation, supporting eosinophilia, boosting pro-allergic activity of eosinophils, increasing IgE production, enhancing the expression of the pro-allergic chemokine receptor, reducing Treg cell differentiation, increasing pro-allergic Th9 responses, as well as supporting mucus secretion and collagen deposition. In this review, we discuss the contrasting roles of SOCS proteins in contexts of allergic disorders to provide new insights regarding the pathophysiology of these diseases and possibly explore SOCS proteins as potential therapeutic targets for alleviating allergies.

Evaluation of SOCS5 mRNA and its association with serum IL-12 levels and rs41379147 SNP in various subsets of allergic disorders: A case control study

BACKGROUND

The SOCS proteins act as suppressors of cytokine signaling by impeding certain signaling pathways. SOCS5, a constituent of the SOCS family, has been associated with the management of allergic reactions, primarily by impeding the signaling of interleukin-4 (IL-4), which is known to have a cardinal function in accelerating the development of an allergic reaction. The key goal of our research was to explore the probable ramifications of the SOCS5 single nucleotide polymorphism (SNP) namely rs41379147 on the expression of SOCS5 mRNA and serum IL-12 levels, as well as to analyze the interaction between SOCS5 genotypes and various clinicopathological parameters in atopic diseases.

METHODS

The study involved the enrollment of 314 subjects comprising 154 atopic individuals and 160 healthy controls. PCR-RFLP was employed to conduct SNP analysis. Real-Time PCR was employed to quantify SOCS5 mRNA. The enzyme-linked immunosorbent assay (ELISA) technique was used for the quantification of interleukin-12 and total IgE levels in the serum while as chemiluminescence was used to determine Vitamin D levels.

RESULTS

The PCR-RFLP analysis indicated a lack of statistically significant variation in genotypic and allelic frequencies between the cases and controls (p > 0.05) for - 9147 C/T SNP either in total atopy (OR-0.70, 95% CI=0.43-1.12, p =0.15), and on subgroup stratifications of chronic urticaria (OR-0.81, 95 % CI = 0.42-1.59, p = 0.61), allergic rhinitis (OR-0.63, 95 % CI = 0.33-1.19, p = 0.16) and bronchial asthma (OR-0.66,95% CI = 0.29-1.4, p=0.32). There was reduced mRNA expression of SOCS5 in total atopic cases, allergic rhinitis, bronchial asthma and chronic urticaria in comparison to controls which advocates the fact that SOCS5 has a protective role in allergic disease development. Despite the reduced amounts of IL-12 in total atopic cases and different allergic disorders in comparison to controls, IL-12 showed significant positive correlation with SOCS5 mRNA expression (p < 0.05).

CONCLUSION

SOCS5 SNP rs41379147(C/T) does not pose any significant risk towards the development of any allergic disorder and has no impact on the expression of SOCS5 and IL-12. Our study has shown the reduced mRNA expression of SOCS5 among individuals diagnosed with chronic urticaria, allergic rhinitis and bronchial asthma and the expression of SOCS5 showed complete dependence on the cytokine milieu of IL12. The modulation of SOCS5 and IL-12 may represent potential curative targets for treating the menace of allergic diseases and present promising avenues for future investigation.

Tissue levels of suppressor of cytokine signaling-3 (SOCS-3) in mycosis fungoides

Mycosis fungoides (MF) is a type of cutaneous T-cell lymphoma with proposed multifactorial etiology. Suppressor of cytokine signaling-3 (SOCS-3) is one of the proteins expressed in MF. Its exact role in disease pathogenesis has not yet been thoroughly investigated. This study aimed to assess the expression of SOCS-3 in patients' skin with mycosis fungoides to elucidate their possible role in the pathogenesis in MF. 30 patients with mycosis fungoides and 30 age and sex-matched healthy controls were included. After clinical examination, tissue levels of SOCS-3 were measured by ELISA. The level of expression of SOCS-3 was significantly upregulated in the lesional tissue compared to perilesional SOCS-3 level in patients' group (P < 0.001), and both levels were higher than the SOCS-3 level in control group (P < 0.001). In addition, there was a statistically significant positive correlation between lesional SOCS-3 level and itching in patients' group (P < 0.001). Regarding lesional and perilesional SOCS-3 levels in each stage, there was a significant increase in lesional SOCS-3 levels in comparison to perilesional level whether in stage Ia, Ib, and IIa; (P < 0.001), (P < 0.001) and (P < 0.001), respectively. Increased tissue levels of SOCS-3 patients with mycosis fungoides point to a role that SOCS-3 could play in its pathogenesis. Also, high levels of SOCS-3 in MF patients with itching suggest a role in the pathogenesis of this symptom. These findings may prove helpful in formulating a new treatment modality in addition to the current treatment of MF.

MicroRNA expression profile of chicken cecum in different stages during Histomonas meleagridis infection

Background

Histomonas meleagridis is an anaerobic, intercellular parasite, which infects gallinaceous birds such as turkeys and chickens. In recent years, the reemergence of Histomoniasis has caused serious economic losses as drugs to treat the disease have been banned. At present, H. meleagridis research focuses on virulence, gene expression analysis, and the innate immunity of the host. However, there are no studies on the differentially expressed miRNAs (DEMs) associated with the host inflammatory and immune responses induced by H. meleagridis. In this research, high-throughput sequencing was used to analyze the expression profile of cecum miRNA at 10 and 15 days post-infection (DPI) in chickens infected with Chinese JSYZ-F strain H. meleagridis.

Results

Compared with the controls, 94 and 127 DEMs were found in cecum of infected chickens at 10 DPI (CE vs CC) and 15 DPI (CEH vs CCH), respectively, of which 60 DEMs were shared at two-time points. Gene Ontology (GO) functional enrichment analysis of the target genes of DEMs indicated that 881 and 1027 GO terms were significantly enriched at 10 and 15 DPI, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG, www.kegg.jp/kegg/kegg1.html) pathway enrichment analysis of the target genes of DEMs demonstrated that 5 and 3 KEGG pathways were significantly enriched at 10 and 15 DPI, respectively. For previous uses, the Kanehisa laboratory have happily provided permission. The integrated analysis of miRNA–gene network revealed that the DEMs played important roles in the host inflammatory and immune responses to H. meleagridis infection by dynamically regulating expression levels of inflammation and immune-related cytokines.

Conclusion

This article not only suggested that host miRNA expression was dynamically altered by H. meleagridis and host but also revealed differences in the regulation of T cell involved in host responses to different times H. meleagridis infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03316-2.

A review of epigenetic changes in asthma: methylation and acetylation

Several studies show that childhood and adulthood asthma and its symptoms can be modulated through epigenetic modifications. Epigenetic changes are inheritable modifications that can modify the gene expression without changing the DNA sequence. The most common epigenetic alternations consist of DNA methylation and histone modifications. How these changes lead to asthmatic phenotype or promote the asthma features, in particular by immune pathways regulation, is an understudied topic. Since external effects, like exposure to tobacco smoke, air pollution, and drugs, influence both asthma development and the epigenome, elucidating the role of epigenetic changes in asthma is of great importance. This review presents available evidence on the epigenetic process that drives asthma genes and pathways, with a particular focus on DNA methylation, histone methylation, and acetylation. We gathered and assessed studies conducted in this field over the past two decades. Our study examined asthma in different aspects and also shed light on the limitations and the important factors involved in the outcomes of the studies. To date, most of the studies in this area have been carried out on DNA methylation. Therefore, the need for diagnostic and therapeutic applications through this molecular process calls for more research on the histone modifications in this disease.

Adoptive transfer of bone marrow-derived dendritic cells (BMDCs) alleviates OVA-induced allergic airway inflammation in asthmatic mice

Airway dendritic cells (DCs) are recognized as important factors in the mechanisms of allergic inflammatory diseases. Suppressor of cytokine signaling 3 (SOCS3) is involved in regulating the functions of T cells and macrophages, but the roles of SOCS3-expressing DCs in the pathogeneses of allergic inflammatory diseases are still controversial. We compared the effects of adoptively transferred SOCS3-/- and SOCS3+/+ bone marrow-derived DCs (BMDCs) on airway inflammation in ovalbumin (OVA)-sensitized asthmatic mice. Adoptive transfer of mature DCs (lipopolysaccharide [LPS]-induced DCs, DClps) with or without SOCS3 gene expression significantly ameliorated allergic airway inflammation. SOCS3-/- DCs slightly attenuated BMDC-induced immunogenic tolerance. DClps migrated to OVA-sensitized lungs with higher efficiency than immature DCs (DCim). DClps with or without SOCS3 greatly improved lung pathology scores and alleviated airway inflammatory cell infiltration after adoptive transfer into mice; they also increased interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) production and inhibited signal transducer and activator of transcription (STAT) 4 and STAT6 signaling in the lungs after OVA sensitization. In conclusion, the BMDC adoptive transfer-induced immunogenic tolerance in OVA-sensitized mice might not be due to SOCS3 gene depletion. BMDC adoptive transfer may be developed into a new approach that alleviates asthma by modulating the balance between immune tolerance and inflammation.

Resident alveolar macrophage-derived vesicular SOCS3 dampens allergic airway inflammation

Resident alveolar macrophages (AMs) suppress allergic inflammation in murine asthma models. Previously we reported that resident AMs can blunt inflammatory signaling in alveolar epithelial cells (ECs) by transcellular delivery of suppressor of cytokine signaling 3 (SOCS3) within extracellular vesicles (EVs). Here we examined the role of vesicular SOCS3 secretion as a mechanism by which AMs restrain allergic inflammatory responses in airway ECs. Bronchoalveolar lavage fluid (BALF) levels of SOCS3 were reduced in asthmatics and in allergen-challenged mice. Ex vivo SOCS3 secretion was reduced in AMs from challenged mice and this defect was mimicked by exposing normal AMs to cytokines associated with allergic inflammation. Both AM-derived EVs and synthetic SOCS3 liposomes inhibited the activation of STAT3 and STAT6 as well as cytokine gene expression in ECs challenged with IL-4/IL-13 and house dust mite (HDM) extract. This suppressive effect of EVs was lost when they were obtained from AMs exposed to allergic inflammation-associated cytokines. Finally, inflammatory cell recruitment and cytokine generation in the lungs of OVA-challenged mice were attenuated by intrapulmonary pretreatment with SOCS3 liposomes. Overall, AM secretion of SOCS3 within EVs serves as a brake on airway EC responses during allergic inflammation, but is impaired in asthma. Synthetic liposomes encapsulating SOCS3 can rescue this defect and may serve as a framework for novel therapeutic approaches targeting airway inflammation.

Skin immunity and its dysregulation in atopic dermatitis, hidradenitis suppurativa and vitiligo

While the epidermis is the frontline defense against infections and indeed, it is a peripheral lymphoid organ, the same immunological mechanisms may initiate and sustain pathological conditions. Indeed, a deregulated action against exogenous pathogens could activate a T cell response in atopic dermatitis, hidradenitis suppurativa and vitiligo. Atopic dermatitis (AD) is a chronic inflammatory skin condition with a complex pathophysiology. Although T helper 2 immunity dysregulation is thought to be the main cause of AD etiopathogenesis, the triggering mechanism is not well understood, and the treatment is often difficult. As the AD, hidradenitis suppurativa (HS) is a chronic inflammatory skin disease with a dramatic impact on the quality of life of the affected patients. The exact pathophysiology of HS is still unclear, but many evidences report a follicular obstruction and subsequent inflammation with TNF-α, interleukin (IL)-1β, IL-10, and IL-17 involvement. Vitiligo is an autoimmune epidermal disorder which consists of melanocytes destruction and skin depigmentation. Melanocytes destruction is mainly due to their increased oxidative-stress sensitivity with a consequent activation of innate first and adaptative immunity (CD8⁺ T cells) later. The understanding of the triggering mechanisms of AD, HS and Vitiligo is pivotal to outline novel therapies aimed at regaining the physiological immune homeostasis of healthy skin. The aim of this review is to provide new insight on the pathogenesis of these skin diseases and to highlight on the new therapeutic approaches adopted in the treatment of AD, HS and Vitiligo.

IL-10 and socs3 Are Predictive Biomarkers of Dengue Hemorrhagic Fever

Background

Cytokines play important roles in the physiopathology of dengue infection; therefore, the suppressors of cytokine signaling (socs) that control the type and timing of cytokine functions could be involved in the origin of immune alterations in dengue.

Objective

To explore the association of cytokine and socs levels with disease severity in dengue patients.

Methods

Blood samples of 48 patients with confirmed dengue infection were analyzed. Amounts of interleukins IL-2, IL-4, IL-6, and IL-10, interferon- (IFN-) γ, and tumor necrosis factor- (TNF-) α were quantified by flow cytometry, and the relative expression of socs1 and socs3 mRNA was quantified by real-time RT-PCR.

Results

Increased levels of IL-10 and socs3 and lower expression of socs1 were found in patients with dengue hemorrhagic fever (DHF) with respect to those with dengue fever (DF) (p < 0.05). Negative correlations were found between socs1 and both IL-10 and socs3 (p < 0.01). The cutoff values of socs3 (>199.8-fold), socs1 (<1.94-fold), and IL-10 (>134 pg/ml) have the highest sensitivity and specificity to discriminate between DF and DHF.

Conclusion

Simultaneous changes in IL-10 and socs1/socs3 could be used as prognostic biomarkers of dengue severity.

[Role of negative regulators of SOCS1, SOCS3, and SOCS5 gene transcription in the negative cell signaling regulation system in asthma]

AIM

To conduct a comprehensive study of the components of negative cell signaling regulation in different types of asthma.

SUBJECTS AND METHODS

A total of 171 people, including 80 patients with allergic asthma (AA), 60 patients with non-allergic asthma (NAA), and 31 apparently healthy individuals, were examined. SOCS5 mRNA expression was assessed by reverse-transcription polymerase chain reaction. The expression of SOCS1 and SOCS3 proteins was investigated by immunoblotting. The concentration of total serum IgE was determined by enzyme immunoassay; the level of cytokines was measured according to the standard protocol using a Bio-Plex fluorometer.

RESULTS

The findings show that the patients with AA generally display more marked changes in the expression of all three investigated SOCSes (SOCS1, SOCS3, and SOCS5) at baseline and when interleukin 4 (IL-4) acts. In NAA, there are pronounced changes in the expression of SOCS3 only and, to a lesser extent, SOCS5. The results of investigating the concentrations of IL-4 in the examined groups demonstrate its significant decrease in the AA group, whereas in the NAA group, it is similar to those in healthy individuals. On the contrary, IL-10 concentrations in AA tend towards those in the control group, but much exceed in NAA.

CONCLUSION

The findings allow one to consider the complexity of regulatory disorders arising at various levels of cell signaling in the context of the multifunctional nature of the molecules from the family of negative regulators of transcription of the SOCS1, SOCS3, and SOCS5 genes, which provide the comprehensive control of cytokine signaling simultaneously in different signal pathways.

New perspectives on the regulation of type II inflammation in asthma

Asthma is a chronic inflammatory disease of the lungs which has been thought to arise as a result of inappropriately directed T helper type-2 (Th2) immune responses of the lungs to otherwise innocuous inhaled antigens. Current asthma therapeutics are directed towards the amelioration of downstream consequences of type-2 immune responses (i.e. β-agonists) or broad-spectrum immunosuppression (i.e. corticosteroids). However, few approaches to date have been focused on the primary prevention of immune deviation. Advances in molecular phenotyping reveal heterogeneity within the asthmatic population with multiple endotypes whose varying expression depends on the interplay between numerous environmental factors and the inheritance of a broad range of susceptibility genes. The most common endotype is one described as "type-2-high" (i.e. high levels of interleukin [IL]-13, eosinophilia, and periostin). The identification of multiple endotypes has provided a potential explanation for the observations that therapies directed at typical Th2 cytokines (IL-4, IL-5, and IL-13) and their receptors have often fallen short when they were tested in a diverse group of asthmatic patients without first stratifying based on disease endotype or severity. However, despite the incorporation of endotype-dependent stratification schemes into clinical trial designs, variation in drug responses are still apparent, suggesting that additional genetic/environmental factors may be contributing to the diversity in drug efficacy. Herein, we will review recent advances in our understanding of the complex pathways involved in the initiation and regulation of type-2-mediated immune responses and their modulation by host factors (genetics, metabolic status, and the microbiome). Particular consideration will be given to how this knowledge could pave the way for further refinement of disease endotypes and/or the development of novel therapeutic strategies for the treatment of asthma .

Delivery of RNAi Therapeutics to the Airways-From Bench to Bedside

RNA interference (RNAi) is a potent and specific post-transcriptional gene silencing process. Since its discovery, tremendous efforts have been made to translate RNAi technology into therapeutic applications for the treatment of different human diseases including respiratory diseases, by manipulating the expression of disease-associated gene(s). Similar to other nucleic acid-based therapeutics, the major hurdle of RNAi therapy is delivery. Pulmonary delivery is a promising approach of delivering RNAi therapeutics directly to the airways for treating local conditions and minimizing systemic side effects. It is a non-invasive route of administration that is generally well accepted by patients. However, pulmonary drug delivery is a challenge as the lungs pose a series of anatomical, physiological and immunological barriers to drug delivery. Understanding these barriers is essential for the development an effective RNA delivery system. In this review, the different barriers to pulmonary drug delivery are introduced. The potential of RNAi molecules as new class of therapeutics, and the latest preclinical and clinical studies of using RNAi therapeutics in different respiratory conditions are discussed in details. We hope this review can provide some useful insights for moving inhaled RNAi therapeutics from bench to bedside.

Histone Modifications and Asthma. The Interface of the Epigenetic and Genetic Landscapes

Complex lung diseases, such as asthma, are influenced by both genetic predisposition and environmental stimuli. The epigenetic landscape of such diseases is attracting increasing interest and research. Epigenetics broadly covers the transient and the inheritable changes to gene expression that are not directly due to changes in nucleotide sequences. Epigenetic mechanisms could have significant impact on asthma-related allergic, immune, and regulatory pathways, as well as on the generation of biomarkers and the heritable transmission of asthma phenotypes. Recent technological advances have allowed mapping of the epigenome and analysis of genome-wide epigenetic contributors to disease. As a result, ground-breaking observations regarding histone post-translational modifications in a number of immunological diseases have emerged. In this review, we look beyond the biological information coded by DNA and review the epigenetic modifications made to histones, with evidence suggesting a role for their modification in asthma.

Methylation and microRNA-mediated epigenetic regulation of SOCS3

Epigenetic gene silencing of several genes causes different pathological conditions in humans, and DNA methylation has been identified as one of the key mechanisms that underlie this evolutionarily conserved phenomenon associated with developmental and pathological gene regulation. Recent advances in the miRNA technology with high throughput analysis of gene regulation further increased our understanding on the role of miRNAs regulating multiple gene expression. There is increasing evidence supporting that the miRNAs not only regulate gene expression but they also are involved in the hypermethylation of promoter sequences, which cumulatively contributes to the epigenetic gene silencing. Here, we critically evaluated the recent progress on the transcriptional regulation of an important suppressor protein that inhibits cytokine-mediated signaling, SOCS3, whose expression is directly regulated both by promoter methylation and also by microRNAs, affecting its vital cell regulating functions. SOCS3 was identified as a potent inhibitor of Jak/Stat signaling pathway which is frequently upregulated in several pathologies, including cardiovascular disease, cancer, diabetes, viral infections, and the expression of SOCS3 was inhibited or greatly reduced due to hypermethylation of the CpG islands in its promoter region or suppression of its expression by different microRNAs. Additionally, we discuss key intracellular signaling pathways regulated by SOCS3 involving cellular events, including cell proliferation, cell growth, cell migration and apoptosis. Identification of the pathway intermediates as specific targets would not only aid in the development of novel therapeutic drugs, but, would also assist in developing new treatment strategies that could successfully be employed in combination therapy to target multiple signaling pathways.

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.

Molecular biology of atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease with specific genetic and immunological mechanisms. The rapid development of new techniques in molecular biology had ushered in new discoveries on the role of cytokines, chemokines, and immune cells in the pathogenesis of AD. New polymorphisms of AD are continually being reported in different populations. The physical and immunological barrier of normal intact skin is an important part of the innate immune system that protects the host against microbials and allergens that are associated with AD. Defects in the filaggrin gene FLG may play a role in facilitating exposure to allergens and microbial pathogens, which may induce Th2 polarization. Meanwhile, Th22 cells also play roles in skin barrier impairment through IL-22, and AD is often considered to be a Th2/Th22-dominant allergic disease. Mast cells and eosinophils are also involved in the inflammation via Th2 cytokines. Release of pruritogenic substances by mast cells induces scratching that further disrupts the skin barrier. Th1 and Th17 cells are mainly involved in chronic phase of AD. Keratinocytes also produce proinflammatory cytokines such as thymic stromal lymphopoietin (TSLP), which can further affect Th cells balance. The immunological characteristics of AD may differ for various endotypes and phenotypes. Due to the heterogeneity of the disease, and the redundancies of these mechanisms, our knowledge of the pathophysiology of the disease is still incomplete, which is reflected by the absence of a cure for the disease.

The signaling suppressor CIS controls proallergic T cell development and allergic airway inflammation

Transcription factors of the STAT family are critical in the cytokine-mediated functional differentiation of CD4(+) helper T cells. Signaling inhibitors of the SOCS family negatively regulate the activation of STAT proteins; however, their roles in the differentiation and function of helper T cells are not well understood. Here we found that the SOCS protein CIS, which was substantially induced by interleukin 4 (IL-4), negatively regulated the activation of STAT3, STAT5 and STAT6 in T cells. CIS-deficient mice spontaneously developed airway inflammation, and CIS deficiency in T cells led to greater susceptibility to experimental allergic asthma. CIS-deficient T cells showed enhanced differentiation into the TH2 and TH9 subsets of helper T cells. STAT5 and STAT6 regulated IL-9 expression by directly binding to the Il9 promoter. Our data thus demonstrate a critical role for CIS in controlling the proallergic generation of helper T cells.

Purification and identification of an IgE suppressor from strawberry in an in vitro immunization system

We purified and identified an IgE suppressor from the strawberry 'Toyonoka', based on the decrease of IgE production in in vitro immunization (IVI). Gel filtration experiment indicated that fractions in a 15-48 kDa range and <10 kDa have an IgE suppressive activity. Furthermore, the fraction in 15-48 kDa was subjected to chromatofocusing and found to have activities at isoelectric points, pI 6.0, 7.0, and 8.0-9.2. We focused on the active fractions of pI 8.0-9.2 and the purified a large amount of strawberry extracts by cation exchange resins in batch. A purified 39 kDa protein showed homology to plant glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in N-terminal amino acid sequence and had GAPDH enzymatic activity. Nucleotide sequence and deduced amino acid sequence of the obtained cDNA clone of the protein matched with the sequence of Fragaria x ananassa GAPDH in the GenBank with >98% identical nucleotides and >99% identical amino acids, respectively. The purified strawberry GAPDH suppressed total IgE production in IVI in a dose-dependent manner. From these results, we identified GAPDH as IgE suppressor in the strawberry. Our study may be applicable to the development of new methods to relieve allergic conditions using GAPDH and the screening of other functional factors for human health.

SOCS2 regulates T helper type 2 differentiation and the generation of type 2 allergic responses

The incidence of allergy and asthma in developed countries is on the increase and this trend looks likely to continue. CD4(+) T helper 2 (Th2) cells are major drivers of these diseases and their commitment is controlled by cytokines such as interleukin 4, which are in turn regulated by the suppressor of cytokine signaling (SOCS) proteins. We report that SOCS2(-/-) CD4(+) T cells show markedly enhanced Th2 differentiation. SOCS2(-/-) mice, as well as RAG-1(-/-) mice transferred with SOCS2(-/-) CD4(+) T cells, exhibit elevated type 2 responses after helminth antigen challenge. Moreover, in in vivo models of atopic dermatitis and allergen-induced airway inflammation, SOCS2(-/-) mice show significantly elevated IgE, eosinophilia, type 2 responses, and inflammatory pathology relative to wild-type mice. Finally, after T cell activation, markedly enhanced STAT6 and STAT5 phosphorylation is observed in SOCS2(-/-) T cells, whereas STAT3 phosphorylation is blunted. Thus, we provide the first evidence that SOCS2 plays an important role in regulating Th2 cell expansion and development of the type 2 allergic responses.

Suppressors of cytokine signaling 3 expression in eosinophils: regulation by PGE₂ and Th2 cytokines

Asthma and nonasthmatic eosinophilic bronchitis (NAEB) are respiratory disorders characterized by a predominance of Th2 cells and eosinophilic inflammation. Suppressors of cytokine signaling (SOCS) proteins play an important role in Th2-mediated allergic responses through control of the balance between Th1 and Th2 cells, particularly, SOCS3 and SOCS5. The aim of this study was to analyze SOCS expression in human peripheral blood eosinophils from patients with asthma, NAEB and healthy controls. SOCS expression in eosinophils from subjects was demonstrated by different techniques. Results showed that expression of SOCS3 in eosinophils and CD4 T cells from patients was higher than in healthy subjects. In addition, we demonstrated that prostaglandin E₂ (PGE₂) and Th2 cytokines are able to upregulate SOCS3 production in eosinophils and attenuate its degranulation. In conclusion, eosinophils are able to transcribe and translate SOCS3 protein and can contribute to the regulation of the Th1/Th2 balance through SOCS3 production.

Gene expression profiling in lungs of chronic asthmatic mice treated with galectin-3: downregulation of inflammatory and regulatory genes

Background. Asthma is a disorder characterized by a predominance of Th2 cells and eosinophilic inflammation. Suppressors of cytokine signaling (SOCS) proteins act as negative regulators of cytokine signaling. In particular, SOCS1 and SOCS3 play an important role in immune response by controlling the balance between Th1 and Th2 cells. In a previous study, we demonstrated that treatment of chronic asthmatic mice with gene therapy using plasmid encoding galectin-3 (Gal-3) led to an improvement in Th2 allergic inflammation. Methods. Using a microarray approach, this study endeavored to evaluate the changes produced by therapeutic Gal-3 delivered by gene therapy in a well-characterized mouse model of chronic airway inflammation. Results were confirmed by real-time RT-PCR, Western blot and immunohistochemical analysis. Results. We identify a set of genes involved in different pathways whose expression is coordinately decreased/increased in mice treated with Gal-3 gene therapy. We report a correlation between Gal-3 treatment and inhibition of SOCS1 and SOCS3 expression in lungs. Conclusion. These results suggest that negative regulation of SOCS1 and 3 following Gal-3 treatment could be a valuable therapeutic approach in allergic disease.

Fms-like tyrosine kinase 3 ligand decreases T helper type 17 cells and suppressors of cytokine signaling proteins in the lung of house dust mite-sensitized and -challenged mice

We previously reported that Fms-like tyrosine kinase 3 ligand (Flt3-L) reversed airway hyperresponsiveness (AHR) and airway inflammation, and increased the number of regulatory CD11c(high)CD8α(high)CD11b(low) dendritic cells and CD4(+)CD25(+)ICOS(+)Foxp3(+)IL-10(+) T-regulatory cells in the lung of allergen-sensitized and -challenged mice. In this study, we evaluated the effect of Flt3-L on Th17 cells and expression of suppressors of cytokine signaling (SOCS) proteins in the lungs of house dust mite (HDM)-sensitized and -challenged mice. BALB/c mice were sensitized and challenged with HDM, and AHR to methacholine was established. Mice were treated with Flt3-L (5 μg, intraperitoneal) daily for 10 days. Levels of IL-4, -5, -6, -8, and -13, and transforming growth factor (TGF)-β in the bronchoalveolar lavage fluid (BALF) were examined by ELISA. Flt3-L treatment reversed existing AHR to methacholine and substantially decreased eosinophils, neutrophils, IL-5, -6, -8, and IL-13, and TGF-β levels in the BALF. HDM-sensitized and -challenged mice showed a significant increase in lung CD4(+)IL-17(+)IL-23R(+)CD25⁻ T cells with high expression of retinoic acid-related orphan receptor (ROR)-γt transcripts. However, administration of Flt3-L substantially decreased the number of lung CD4(+)IL-17(+)IL-23R(+)CD25⁻ T cells, with significantly decreased expression of ROR-γt mRNA in these cells. HDM sensitization caused a significant increase in the expression of SOCS-1, -3, and -5 in the lung. Flt3-L treatment abolished the increase in SOCS-1 and SOCS-3 proteins, whereas SOCS-5 expression was significantly reduced. These data suggest that the therapeutic effect of Flt3-L in reversing the hallmarks of allergic asthma in a mouse model is mediated by decreasing IL-6 and TGF-β levels in the BALF, which, in turn, decrease CD4(+)IL-17(+)IL-23R(+)ROR-γt(+)CD25⁻ T cells and the expression of SOCS-1 and SOCS-3 in the lung of HDM-sensitized and -challenged mice.

Suppressors of cytokine signaling (SOCS) in T cell differentiation, maturation, and function

Cytokines are key modulators of T cell biology, but their influence can be attenuated by suppressors of cytokine signaling (SOCS), a family of proteins consisting of eight members, SOCS1-7 and CIS. SOCS proteins regulate cytokine signals that control the polarization of CD4(+) T cells into Th1, Th2, Th17, and T regulatory cell lineages, the maturation of CD8(+) T cells from naïve to "stem-cell memory" (Tscm), central memory (Tcm), and effector memory (Tem) states, and the activation of these lymphocytes. Understanding how SOCS family members regulate T cell maturation, differentiation, and function might prove critical in improving adoptive immunotherapy for cancer and therapies aimed at treating autoimmune and infectious diseases.

The T cell STAT signaling network is reprogrammed within hours of bacteremia via secondary signals

The delicate balance between protective immunity and inflammatory disease is challenged during sepsis, a pathologic state characterized by aspects of both a hyperactive immune response and immunosuppression. The events driven by systemic infection by bacterial pathogens on the T cell signaling network that likely control these responses have not been illustrated in great detail. We characterized how intracellular signaling within the immune compartment is reprogrammed at the single cell level when the host is challenged with a high level of pathogen. To accomplish this, we applied flow cytometry to measure the phosphorylation potential of key signal transduction proteins during acute bacterial challenge. We modeled the onset of sepsis by i.v. administration of avirulent strains of Listeria monocytogenes and Escherichia coli to mice. Within 6 h of bacterial challenge, T cells were globally restricted in their ability to respond to specific cytokine stimulations as determined by assessing the extent of STAT protein phosphorylation. Mechanisms by which this negative feedback response occurred included SOCS1 and SOCS3 gene up-regulation and IL-6-induced endocystosis of the IL-6 receptor. Additionally, macrophages were partially tolerized in their ability to respond to TLR agonists. Thus, in contrast to the view that there is a wholesale immune activation during sepsis, one immediate host response to blood-borne bacteria was induction of a refractory period during which leukocyte activation by specific stimulations was attenuated.

Altered interleukin-6 receptor, IL-6R and gp130, production and expression and decreased SOCS-3 expression in placentas from women with pre-eclampsia

Interleukin-6 (IL-6) and its receptor complex, IL-6 receptor (IL-6R) and gp130, are critical in induction of suppressor of cytokine signalling-3 (SOCS-3) protein, a negative cytokine regulator and anti-inflammatory mediator, in a biological system. Increased inflammatory response is believed to contribute to the placental dysfunction in pre-eclampsia (PE). However, it is not known if altered IL-6 receptor signalling and decreased SOCS-3 expression occur in placentas from PE. To study this, we examined IL-6, soluble IL-6R (sIL-6R) and soluble gp130 (sgp130) production by villous tissue from normal and PE placentas. Hypoxia effects on IL-6, sIL-6R and sgp130 production was determined. IL-6R, gp130 and SOCS-3 expression were determined by immunohistochemical staining and by Western blot. Our results showed that under normoxic conditions (21% O(2)), villous tissue from PE placentas produced relative more sgp130, but significantly less IL-6 and sIL-6R (p<0.01) than normal placental tissue. The ratio of sgp130/sIL-6R release was significantly higher by PE placentas than normal placentas, p<0.01. Under hypoxic conditions (2% O(2)), IL-6 production was significantly reduced by both normal (p<0.01) and PE (p<0.05) placental tissue. Hypoxia promoted sgp130 release by normal, but not by PE, placental tissue. Reduced IL-6R and SOCS-3 immunostaining and expression were found in PE placentas. We concluded that increased ratio of sgp130/sIL-6R production and/or reduced sIL-6R production combined with down-regulation of IL-6R and SOCS-3 expression in trophoblasts may lead to less cytokine inhibitory activity in PE placentas, which may account for the increased placental inflammatory response in PE.

Respiratory syncytial virus (RSV) attachment and nonstructural proteins modify the type I interferon response associated with suppressor of cytokine signaling (SOCS) proteins and IFN-stimulated gene-15 (ISG15)

Respiratory syncytial virus (RSV) is a major cause of severe lower airway disease in infants and young children, but no safe and effective RSV vaccine is yet available. Factors attributing to this problem are associated with an incomplete understanding of the mechanisms by which RSV modulates the host cell response to infection. In the present study, we investigate suppressor of cytokine signaling (SOCS)-1 and SOCS3 expression associated with the type I IFN and IFN-stimulated gene (ISG)-15 response following infection of mouse lung epithelial (MLE-15) cells with RSV or RSV mutant viruses lacking the G gene, or NS1 and NS2 gene deletions. Studies in MLE-15 cells are important as this cell line represents the distal bronchiolar and alveolar epithelium of mice, the most common animal model used to evaluate the host cell response to RSV infection, and exhibit morphologic characteristics of alveolar type II cells, a primary cell type targeted during RSV infection. These results show an important role for SOCS1 regulation of the antiviral host response to RSV infection, and demonstrate a novel role for RSV G protein manipulation of SOCS3 and modulation of ISG15 and IFNβ mRNA expression.

New drugs targeting Th2 lymphocytes in asthma

Asthma represents a profound worldwide public health problem. The most effective anti-asthmatic drugs currently available include inhaled beta2-agonists and glucocorticoids and control asthma in about 90-95% of patients. The current asthma therapies are not cures and symptoms return soon after treatment is stopped even after long term therapy. Although glucocorticoids are highly effective in controlling the inflammatory process in asthma, they appear to have little effect on the lower airway remodelling processes that appear to play a role in the pathophysiology of asthma at currently prescribed doses. The development of novel drugs may allow resolution of these changes. In addition, severe glucocorticoid-dependent and resistant asthma presents a great clinical burden and reducing the side-effects of glucocorticoids using novel steroid-sparing agents is needed. Furthermore, the mechanisms involved in the persistence of inflammation are poorly understood and the reasons why some patients have severe life threatening asthma and others have very mild disease are still unknown. Drug development for asthma has been directed at improving currently available drugs and findings new compounds that usually target the Th2-driven airway inflammatory response. Considering the apparently central role of T lymphocytes in the pathogenesis of asthma, drugs targeting disease-inducing Th2 cells are promising therapeutic strategies. However, although animal models of asthma suggest that this is feasible, the translation of these types of studies for the treatment of human asthma remains poor due to the limitations of the models currently used. The myriad of new compounds that are in development directed to modulate Th2 cells recruitment and/or activation will clarify in the near future the relative importance of these cells and their mediators in the complex interactions with the other pro-inflammatory/anti-inflammatory cells and mediators responsible of the different asthmatic phenotypes. Some of these new Th2-oriented strategies may in the future not only control symptoms and modify the natural course of asthma, but also potentially prevent or cure the disease.

Different regulation of T helper 1- and T helper 2-promoting cytokine signalling factors in human dendritic cells after exposure to protein versus contact allergens

Cytokine-dependent T helper 1 (Th1) differentiation versus T helper 2 (Th2) differentiation is controlled by distinct transcription factors. Previously, we have demonstrated that immature human dendritic cells (DC) from blood donors with allergies show rapid phosphorylation of the Th2-associated signal transducer and activator of transcription 6 (STAT6) upon contact with protein allergens. In the present study we investigated whether this process is regulated by the downstream molecules suppressor of cytokine signalling (SOCS) and/or by the factors T-bet and GATA3. Therefore, immature DC of grass or birch pollen-allergic donors were treated with the respective Th2-promoting protein allergens, and, for comparison, with the Th1-promoting contact allergen 5-chloro-2-methylisothiazolinone plus 2-methylisothiazolinone (MCI/MI) or with the antigen tetanus toxoid. Changes in the mRNA levels of SOCS1, SOCS3, T-bet and GATA3 were analysed by quantitative real-time polymerase chain reaction. Exposure of DC to protein allergens led to the up-regulation of the Th2-associated genes SOCS3 and GATA3, whereas the contact allergen MCI/MI preferentially enhanced the expression of the Th1-associated gene T-bet. Treatment of immature DC with the antigen tetanus toxoid increased both Th1- and Th2-associated genes. Our data indicate that polarization of type 1 versus type 2 immune responses takes place already at the level of antigen-presenting cells, involving molecules similar to those used in T-cell polarization.