Browsing by Author "Khan, Deena"

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    Deletion of microRNA-183-96-182 Cluster in Lymphocytes Suppresses Anti-DsDNA Autoantibody Production and IgG Deposition in the Kidneys in C57BL/6-Fas(lpr/lpr) Mice
    Wang, Zhuang; Heid, Bettina; Lu, Ran; Sachdeva, Mohit; Edwards, Michael R.; Ren, JingJing; Cecere, Thomas E.; Khan, Deena; Jeboda, Taschua; Kirsch, David G.; Reilly, Christopher M.; Dai, Rujuan; Ahmed, S. Ansar (Frontiers, 2022-07-07)
    Dysregulated miRNAs have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). Our previous study reported a substantial increase in three miRNAs located at the miR-183-96-182 cluster (miR-183C) in several autoimmune lupus-prone mice, including MRL/lpr and C57BL/6-lpr (B6/lpr). This study reports that in vitro inhibition of miR-182 alone or miR-183C by specific antagomirs in activated splenocytes from autoimmune-prone MRL/lpr and control MRL mice significantly reduced lupus-related inflammatory cytokines, interferon-gamma (IFN gamma), and IL-6 production. To further characterize the role of miR-182 and miR-183C cluster in vivo in lupus-like disease and lymphocyte phenotypes, we used hCD2-iCre to generate B6/lpr mice with conditional deletion of miR-182 or miR-183C in CD2(+) lymphocytes (miR-182(-/-)B6/lpr and miR-183C(-/-)B6/lpr). The miR-182(-/-)B6/lpr and miR-183C(-/-)B6/lpr mice had significantly reduced deposition of IgG immunocomplexes in the kidney when compared to their respective littermate controls, although there appeared to be no remarkable changes in renal pathology. Importantly, we observed a significant reduction of serum anti-dsDNA autoantibodies in miR-183C(-/-)B6/lpr mice after reaching 24 weeks-of age compared to age-matched miR-183C(fl/fl)B6/lpr controls. In vitro activated splenocytes from miR-182(-/-)B6/lpr mice and miR-183C(-/-)B6/lpr mice showed reduced ability to produce lupus-associated IFN gamma. Forkhead box O1(Foxo1), a previously validated miR-183C miRNAs target, was increased in the splenic CD4(+) cells of miR-182(-/-)B6/lpr and miR-183C(-/-)B6/lpr mice. Furthermore, in vitro inhibition of Foxo1 with siRNA in splenocytes from miR-182(-/-)B6/lpr and miR-183C(-/-)B6/lpr mice significantly increased IFN gamma expression following anti-CD3/CD28 stimulation, suggesting that miR-182 and miR-183C miRNAs regulate the inflammatory IFN gamma in splenocytes via targeting Foxo1. The deletion of either miR-182 alone or the whole miR-183C cluster, however, had no marked effect on the composition of T and B cell subsets in the spleens of B6/lpr mice. There were similar percentages of CD4(+), CD8(+), CD19(+), as well as Tregs, follicular helper T (T-FH), germinal center B (GCB), and plasma cells in the miR-183C(-/-)B6/lpr and miR-182(-/-)B6/lpr mice and their respective littermate controls, miR-183C(fl/fl)B6/lpr and miR-182(fl/fl)B6/lpr mice. Together, our data demonstrate a role of miR-183C in the regulation of anti-dsDNA autoantibody production in vivo in B6/lpr mice and the induction of IFN gamma in in vitro activated splenocytes from B6/lpr mice.
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    Identification of a Common Lupus Disease-Associated microRNA Expression Pattern in Three Different Murine Models of Lupus
    Dai, Rujuan; Zhang, Yan; Khan, Deena; Heid, Bettina; Caudell, David L.; Crasta, Oswald R.; Ahmed, Sattar Ansar (PLOS, 2010-12-10)
    Background Recent reports have shown that microRNAs (miRNAs) regulate vital immunological processes and have emerged as key regulators of immune system development and function. Therefore, it is important to determine miRNA dysregulation and its pathogenic contribution in autoimmune diseases, an aspect not adequately addressed thus far. Methodology/Principal Findings In this study, we profiled miRNA expressions in splenic lymphocytes from three murine lupus models (MRL-lpr, B6-lpr and NZB/WF1) with different genetic background by miRNA microarray assays and Real-time RT-PCR. Despite the genetic differences among these three lupus stains, a common set of dysregulated miRNAs (miR-182-96-183 cluster, miR-31, and miR-155) was identified in splenocytes when compared with age-matched control mice. The association of these miRNAs with the disease was highlighted by our observation that this miRNA expression pattern was evident in NZB/W mice only at an age when lupus disease is manifested. Further, we have shown that the miRNA dysregulation in MRL-lpr mice was not simply due to the activation of splenocytes. By Real-time RT-PCR, we confirmed that these miRNAs were upregulated in both purified splenic B and T cells from MRL-lpr mice. miR-127 and miR-379, which were greatly upregulated in splenocytes from lpr mice, were moderately increased in diseased NZB/W mice. In addition, Real-time RT-PCR revealed that miR-146a, miR-101a, and miR-17-92 were also markedly upregulated in splenic T, but not B cells from MRL-lpr mice. Conclusions/Significance The identification of common lupus disease-associated miRNAs now forms the basis for the further investigation of the pathogenic contribution of these miRNAs in autoimmune lupus, which will advance our knowledge of the role of miRNAs in autoimmunity. Given that miRNAs are conserved, with regard to both evolution and function, our observation of a common lupus disease-associated miRNA expression pattern in murine lupus models is likely to have significant pathogenic, diagnostic, and/or therapeutic implications in human lupus.
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    Molecular Basis of Upregulation of IL-17 in Estrogen Model of Inflammation
    Khan, Deena (Virginia Tech, 2012-06-20)
    Interleukin-17 (IL-17) plays a major role in inflammation by regulating the induction of various proinflammatory genes, which aid in the recruitment and activation of neutrophils. Although IL-17 is considered to be protective in infection, overproduction of IL-17 in conditions like autoimmune diseases has been shown to aggravate these diseases and contribute to tissue injury. One of the principal focus of our laboratory is to decipher molecular mechanisms involved in inflammatory cytokine regulation and response in inflammatory disorders. To study this aspect, we employ a murine model of pro-inflammation induced by exposure to a natural immunomodulator, estrogen. In this novel study, we have comprehensively investigated the effect of estrogen on IL-17 induction, an aspect not studied thus far. We are the first to demonstrate that estrogen increases the ability of lymphocytes to secrete IL-17A, and its isoforms IL-17F, IL-17A/F. In addition to the cytokine levels, the percentages of IL-17⁺ cells are also increased by estrogen. Impressively, we found that estrogen fine tunes the balance of multiple transcription factors/signaling pathways. Estrogen upregulates IL-17 by promoting the activity and expression of positive regulators (RORγt, RORα, NF-κB, JAK-2) and decreases the activity and/or expression of negative regulators (IRF8, ETS-1). In addition, we found that estrogen epigenetically regulates IL-17 induction by miRNAs (miR-326 and miR-223). We also found that majority of IL-17 positive cells are CD8⁺ suggesting that estrogen-mediated IL-17 induction is predominantly from Tc17 cells. This is possibly due to increased proliferation of CD8⁺ cells from estrogen-treated mice, as demonstrated by CFSE cell proliferation assay. Furthermore, estrogen also enhances the ability of IL-17-target cells to release proinflammatory molecules when exposed to IL-17. Together, this is the first study to comprehensively show that estrogen calibrates transcription factors and miRNAs to enhance IL-17 induction and promote IL-17 response. This dissertation work will provide a platform to continue further research in estrogen modulation of IL-17 in inflammation and disease conditions.
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    Neutrophils and neutrophil serine proteases are increased in the spleens of estrogen-treated C57BL/6 mice and several strains of spontaneous lupus-prone mice
    Dai, Rujuan; Cowan, Catharine; Heid, Bettina; Khan, Deena; Liang, Zhihong; Pham, Christine T.N.; Ahmed, Sattar Ansar (PLOS, 2017-02-13)
    Estrogen, a natural immunomodulator, regulates the development and function of diverse immune cell types. There is now renewed attention on neutrophils and neutrophil serine proteases (NSPs) such as neutrophil elastase (NE), proteinase 3 (PR3), and cathepsin G (CG) in inflammation and autoimmunity. In this study, we found that although estrogen treatment significantly reduced total splenocytes number, it markedly increased the splenic neutrophil absolute numbers in estrogen-treated C57BL/6 (B6) mice when compared to placebo controls. Concomitantly, the levels of NSPs and myeloperoxidase (MPO) were highly upregulated in the splenocytes from estrogen-treated mice. Despite the critical role of NSPs in the regulation of non-infectious inflammation, by employing NE-/-/PR3-/-/CG-/- triple knock out mice, we demonstrated that the absence of NSPs affected neither estrogen's ability to increase splenic neutrophils nor the induction of inflammatory mediators (IFNγ, IL-1β, IL-6, TNFα, MCP-1, and NO) from ex vivo activated splenocytes. Depletion of neutrophils in vitro in splenocytes with anti-Ly6G antibody also had no obvious effect on NSP expression or LPS-induced IFNγ and MCP-1. These data suggest that estrogen augments NSPs, which appears to be independent of enhancing ex vivo inflammatory responses. Since estrogen has been implicated in regulating several experimental autoimmune diseases, we extended our observations in estrogen-treated B6 mice to spontaneous autoimmune-prone female MRL-lpr, B6-lpr and NZB/WF1 mice. There was a remarkable commonality with regards to the increase of neutrophils and concomitant increase of NSPs and MPO in the splenic cells of different strains of autoimmune-prone mice and estrogen-treated B6 mice. Collectively, since NSPs and neutrophils are involved in diverse pro-inflammatory activities, these data suggest a potential pathologic implication of increased neutrophils and NSPs that merits further investigation.
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    Regulation of IL-17 in autoimmune diseases by transcriptional factors and microRNAs
    Khan, Deena; Ahmed, Sattar Ansar (Frontiers, 2015-07-14)
    In recent years, IL-17A (IL-17), a pro-inflammatory cytokine, has received intense attention of researchers and clinicians alike with documented effects in inflammation and autoimmune diseases. IL-17 mobilizes, recruits and activates different cells to increase inflammation. Although protective in infections, overproduction of IL-17 promotes inflammation in autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, psoriasis, among others. Regulating IL-17 levels or action by using IL-17-blocking antibodies or IL-17R antagonist has shown to attenuate experimental autoimmune diseases. It is now known that in addition to IL-17-specific transcription factor, ROR gamma t, several other transcription factors and select microRNAs (miRNA) regulate IL-17. Given that miRNAs are dysregulated in autoimmune diseases, a better understanding of transcriptional factors and miRNA regulation of IL-17 expression and function will be essential for devising potential new therapies. In this review, we will overview IL-17 induction and function in relation to autoimmune diseases. In addition, current findings on transcriptional regulation of IL-17 induction and plausible interplay between IL-17 and miRNA in autoimmune diseases are highlighted.