IL-22 as a target for therapeutic intervention: Current knowledge on its role in various diseases.

IL-22 has emerged as a crucial cytokine mediating protective response against pathogens and tissue regeneration. Dysregulated production of IL-22 has been shown to play a pivotal role in the pathogenesis of various diseases like malignant tumours, viral, cardiovascular, allergic and autoimmune disorders. Interleukin 22 belongs to IFN-IL-10 cytokine family. It is a major proinflammatory cytokine secreted by activated Th1 cells (Th22), though can also be secreted by many other immune cells like group 3 innate lymphocytes, γδ T cells, NK cells, NK T cells, and mucosal associated invariant T cells. Th22 cells exclusively release IL-22 but not IL-17 or IFN-γ (as Th1 cells releases IFN-γ along with IL-22 and Th17 cells releases IL-17 along with IL-22) and also express aryl hydrocarbon receptor as the key transcription factor. Th22 cells also exhibit expression of chemokine receptor CCR6 and skin-homing receptors CCR4 and CCR10 indicating the involvement of this subset in bolstering epithelial barrier immunity and promoting secretion of antimicrobial peptides (AMPs) from intestinal epithelial cells. The function of IL-22 is modulated by IL-22 binding protein (binds to IL-22 and inhibits it binding to its cell surface receptor); which serves as a competitor for IL-22R1 chain of IL-22 receptor. The pathogenic and protective nature of the Th22 cells is modulated both by the site of infected tissue and the type of disease pathology. This review aims to discuss key features of IL-22 biology, comparisons between IL and 22 and IFN-γ and its role as a potential immune therapy target in different maladies.

Metabolic reprograming of tumor-associated macrophages.

A large body of scientific evidence corroborated by clinical and animal model experiments indicates that tumor-associated macrophages (TAMs) play a crucial role in tumor development and progression. TAMs are a key immune cell type present in tumor microenvironment (TME) and associated with poor prognosis, drug resistance, enhanced angiogenesis and metastasis in cancer. TAMs are a phenotypically diverse population of myeloid cells which display tremendous plasticity and dynamic metabolic nature. A complete interpretation of pro-tumoral and anti-tumoral metabolic switch in TAMs is essential to understand immune evasion mechanisms in cancer. Recent studies have also implicated epigenetic mechanisms as significantly regulators of TAM functions. In this review we provide an overview of metabolic circuitry in TAMs, its impact on immune effector cells and interventions aimed at rewiring the metabolic circuits in TAMs. Mechanisms responsible for TAM polarization in cancer are also discussed.

Augmentation of IL-6 production contributes to development of gestational diabetes mellitus: An Indian study.

AIM: Inflammatory mediators like interleukin-6 (IL-6) and acute phase protein like C-reactive protein (CRP) are supposed to contribute to development of GDM, however clinical data supporting this hypothesis is limited. This study was designed to analyze the association of IL-6 and CRP with development of GDM in Indian females. METHODS: This case control study included pregnant women diagnosed as GDM (n = 53) and those having normal glucose tolerance (n = 50). Serum levels of IL-6 and CRP were analysed and correlated with various clinical parameters. RESULTS: Serum IL-6 levels were significantly high (p < 0.05) in GDM females as compared to control females. IL-6 levels correlated with pre-pregnancy body mass index (BMI), fasting blood sugar (FBS) and postprandial sugar (PPBS). Unlike IL-6, CRP levels did not show significant differences between GDM and control females. However, positive correlation of CRP levels with BMI, FBS and PPBS was observed. CONCLUSION: High IL-6 levels in gestational diabetes may indicate a possible role for inflammation in pathophysiology of GDM.

Role of immunological markers in gestational diabetes mellitus-a brief review.

Gestational Diabetes Mellitus (GDM) is a condition which develops due to insulin resistance. There are a number of immunological markers (IL-6, TNF-α, IL-10, etc), which play significant role during normal pregnancy and their irregular levels could likely cause some level of insulin resistance. There are studies which have compared the levels of different immunological mediators in GDM affected females and their healthy controls, but their findings are little controversial. Some of the studies have reported increased levels of IL-6, TNF-α, adiponectin, leptin, in females affected with GDM, while others do not confirm this. We have tried to summarize, in this short review, the findings of research studies being conducted globally, which have reported the association of insulin resistance, GDM and immunological markers. Our review suggests that there is a need for high quality data on the immunological parameters associated with GDM, especially from India.

GCK Gene Screening and Association of GCK Variants With Gestational Diabetes in North Indian Population.

BACKGROUND: GCK gene variants have been reported to be associated with gestational diabetes mellitus (GDM) in the Caucasian population. There are no reports exploring this association in the Indian population. METHODS: This cross-sectional study included subjects from Max Super Speciality Hospital, New Delhi, India, over a span of 6 months. Females diagnosed with GDM as per the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) criteria were enrolled. Direct gene sequencing was performed to screen all 10 exons and promoter region of GCK gene. RESULTS: Out of the total 1000 females screened, 154 subjects had any degree of hyperglycemia. GCK gene screening was done and we observed 11 variants in 80.4% (41/51) of the GDM subset and 89.6% (43/48) of the controls. Allele frequencies of observed variants were not different between the control subjects (12.5%) and those diagnosed with GDM (8.4%). CONCLUSION: To the best of our knowledge, this is the first report from north India exploring association of GCK variants with GDM and we do not observe any association of GCK variants with GDM in our study population.CTRI Registration No: CTRI/2017/07/008964.

Immunotherapy approach with recombinant survivin adjuvanted with alum and MIP suppresses tumor growth in murine model of breast cancer.

Survivin has received attention as a potential target for cancer immunotherapy because of its crucial role in oncogenesis. We undertook this study to evaluate the immunotherapeutic potential of combination of recombinant survivin along with adjuvant alum and immune modulator Mycobacterium indicus pranii (MIP). In vivo efficacy of the combination was studied in an invasive murine breast cancer model. Recombinant survivin protein was purified from Escherichia coli based expression system and characterized by western blotting. Purified survivin protein was combined with alum and MIP and was used for immunization of Balb/c mice. Antigen-primed animals were then challenged with syngeneic mammary tumor cells known as 4T-1. Balb/c mice spontaneously develop tumor when inoculated with 4T-1 cells. Antigen and adjuvant combination was immunogenic and significantly suppressed tumor growth in mice immunized with combination of recombinant survivin (10 µg), alum, and MIP. This is the first report that describes a combination immunotherapy approach using recombinant survivin, alum, and MIP in highly metastatic murine breast cancer model and holds promise for development of new biotherapeutics for cancer.

Combination immunotherapy with Survivin and luteinizing hormone-releasing hormone fusion protein in murine breast cancer model.

AIM: To investigate the therapeutic potential of two recombinant proteins, Survivin and luteinizing hormone-releasing hormone (LHRH) fusion protein [LHRH(6leu)-LTB] for immunotherapy of breast cancer. METHODS: Murine 4T-1 breast cancer model was used to evaluate the efficacy of recombinant proteins in vivo. Twenty four Balb/c mice were divided into 4 groups of 6 mice each. Recombinant Survivin and LHRH fusion protein, alone or in combination, were administered along with immunomodulator Mycobacterium indicus pranii (MIP) in Balb/c mice. Unimmunized or control group mice were administered with phosphate buffer saline. Each group was then challenged with syngeneic 4T-1 cells to induce the growth of breast tumor. Tumor growth was monitored to evaluate the efficacy of immune-response in preventing the growth of cancer cells. RESULTS: Preventive immunization with 20 µg recombinant Survivin and MIP was effective in suppressing growth of 4T-1 mouse model of breast cancer (P = 0.04) but 50 µg dose was ineffective in suppressing tumor growth. However, combination of Survivin and LHRH fusion protein was more effective in suppressing tumor growth (P = 0.02) as well as metastasis in vivo in comparison to LHRH fusion protein as vaccine antigen alone. CONCLUSION: Recombinant Survivin and MIP suppress tumor growth significantly. Combining LHRH fusion protein with Survivin and MIP enhances tumor suppressive effects marginally which provides evidence for recombinant Survivin and LHRH fusion protein as candidates for translating the combination cancer immunotherapy approaches.

Role of the Functional Polymorphism of Survivin Gene (-31G/C) and Risk of Breast Cancer in a North Indian Population.

INTRODUCTION: Survivin is an apoptosis inhibitor and plays a primary role in cancer development and progression. One of the most common polymorphism of the survivin promoter -31G/C (rs9904341) influences its expression and is associated with the risk of cancer development. This study was conducted to explore survivin promoter gene -31G/C (rs9904341) polymorphism and the risk of breast cancer. PATIENTS AND METHODS: The study group included 190 pathologically confirmed breast cancer patients, in addition to 200 distinct cancer-free controls from Jammu and Kashmir region of India, where breast cancer is the most common cancer in women. Single nucleotide polymorphism genotyping for -31G/C polymorphism in the survivin promoter region was done using a polymerase chain reaction-restriction fragment length polymorphism method. RESULTS: The variant genotype/allele was found in 54.1% of the cases compared with 46.5% of controls. The combined prevalence of genotype GC+CC was significantly higher in patients compared with the control group (P = .02). Analyses of odds ratios (ORs) in the patient and control groups indicated that the presence of homozygous CC genotype was associated with increased risk for development of breast cancer (OR, 2.04; 95% confidence interval [CI], 1.07-2.98). The gene frequencies for G and C alleles were statistically different between patient and control groups (OR, 1.37; 95% CI, 1.03-1.84). CONCLUSION: The results suggest the association of -31G/C survivin polymorphism at a genotypic and allelic level in breast cancer.

Survivin: a unique target for tumor therapy.

Survivin is the smallest member of the Inhibitor of apoptosis (IAP) family of proteins, involved in inhibition of apoptosis and regulation of cell cycle. These functional attributes make Survivin a unique protein exhibiting divergent functions i.e. regulating cell proliferation and cell death. Expression pattern of Survivin is also distinctive; it is prominently expressed during embryonal development, absent in most normal, terminally differentiated tissues but upregulated in a variety of human cancers. Expression of Survivin in tumours correlates with not only inhibition of apoptosis and a decreased rate of cell death, but also resistance to chemotherapy and aggressiveness of tumours. Therefore, Survivin is an important target for cancer vaccines and therapeutics. Survivin has also been found to be prominently expressed on both human and embryonic stem cells and many somatic stem cell types indicating its yet unexplored role in stem cell generation and maintenance. Overall, Survivin emerges as a molecule with much wider role in cellular homeostasis. This review will discuss various aspects of Survivin biology and its role in regulation of apoptosis, cell division, chemo-resistance and tumour progression. Various molecular and immunotherapeutic approaches targeting Survivin will also be discussed.

Dicer insufficiency and microRNA-155 overexpression in lupus regulatory T cells: an apparent paradox in the setting of an inflammatory milieu.

Systemic lupus erythematosus is a chronic autoimmune disease characterized by loss of tolerance to self-Ags and activation of autoreactive T cells. Regulatory T (Treg) cells play a critical role in controlling the activation of autoreactive T cells. In this study, we investigated mechanisms of potential Treg cell defects in systemic lupus erythematosus using MRL-Fas(lpr/lpr) (MRL/lpr) and MRL-Fas(+/+) mouse models. We found a significant increase in CD4(+)CD25(+)Foxp3(+) Treg cells, albeit with an altered phenotype (CD62L(-)CD69(+)) and with a reduced suppressive capacity, in the lymphoid organs of MRL strains compared with non-autoimmune C3H/HeOuj mice. A search for mechanisms underlying the altered Treg cell phenotype in MRL/lpr mice led us to find a profound reduction in Dicer expression and an altered microRNA (miRNA, miR) profile in MRL/lpr Treg cells. Despite having a reduced level of Dicer, MRL/lpr Treg cells exhibited a significant overexpression of several miRNAs, including let-7a, let-7f, miR-16, miR-23a, miR-23b, miR-27a, and miR-155. Using computational approaches, we identified one of the upregulated miRNAs, miR-155, that can target CD62L and may thus confer the altered Treg cell phenotype in MRL/lpr mice. In fact, the induced overexpression of miR-155 in otherwise normal (C3H/HeOuj) Treg cells reduced their CD62L expression, which mimics the altered Treg cell phenotype in MRL/lpr mice. These data suggest a role of Dicer and miR-155 in regulating Treg cell phenotype. Furthermore, simultaneous appearance of Dicer insufficiency and miR-155 overexpression in diseased mice suggests a Dicer-independent alternative mechanism of miRNA regulation under inflammatory conditions.

Downregulation of CCR5 on activated CD4 T cells in HIV-infected Indians.

BACKGROUND: HIV infection in India is unique as it occurs predominantly by CCR5-utilizing isolates that exhibit no co-receptor switch. OBJECTIVES: To study HIV-1 co-receptor dynamics on T cells and monocytes following viral infection. STUDY DESIGN: HIV co-receptor expression was evaluated by flow cytometry on various cell subsets in HIV-infected Indians and in vitro in human peripheral blood mononuclear cells infected with CCR5- or CXCR4-utilizing HIV-1. Transfection of the T cell line CEM-CCR5 (which expresses CD4, CCR5 and CXCR4) with HIV-1 Nef or Vpu expression vectors, or treatment with recombinant soluble gp120 from CCR5- and CXCR4-tropic HIV-1, was carried out to determine their effects on co-receptor expression. RESULTS: Indian HIV patients had fewer CD4+CCR5+ T cells and CCR5-expressing activated CD4+ T cells, but higher CXCR4-expressing activated CD4+ T cells compared with controls. Expression of CCR5 was not different on monocytes in HIV patients as compared to controls. The CCR5 downregulation on T cells was HIV infection specific and was governed by the co-receptor-utilization phenotype of the virus. The Nef and soluble gp120 proteins induced CCR5 downregulation, the latter in a co-receptor-utilization phenotype specific manner. CONCLUSIONS: The HIV-1 co-receptor dynamics in Indian patients is distinct from western patients and depends upon the virus surface protein. We propose this to be a viral survival strategy.

Expression of interferon-gamma and tumor necrosis factor-alpha in bone marrow T cells and their levels in bone marrow plasma in patients with aplastic anemia.

Immune-mediated stem cell damage has been postulated to be responsible for disease initiation and progression in aplastic anemia (AA). It is hypothesized that T lymphocytes play a major role in destroying the bone marrow (BM) stem cells of AA patients by infiltrating the BM and secreting excessive levels of anti-hematopoietic cytokines, interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha). We undertook this study to assess the pathogenic significance of anti-hematopoietic cytokines such as IFN-gamma and TNF-alpha in BM T cells and plasma of AA patients. Significantly elevated levels of IFN-gamma and TNF-alpha were found in the BM plasma of AA patients compared to controls (p=0.05 and 0.006, respectively). Intracellular IFN-gamma and not TNF-alpha in BM CD3+ T cells of AA patients was significantly higher compared to controls (p=0.04 and p=0.2, respectively). A follow-up analysis of expression of these cytokines in BM T cells and their levels in BM plasma in five AA patients before and 180 days (6 months) after antithymocyte globulin (ATG) and cyclosporin A (CsA) therapy showed a decline 180 days after therapy compared to pre-therapy. We thus conclude that increased production of both IFN-gamma and TNF-alpha in the BM may contribute to disease pathogenesis in AA and ATG therapy may induce hematological remission by suppressing the elevated levels of IFN-gamma and TNF-alpha in AA BM.