TY - JOUR A1 - Kader, Hidaya A. A1 - Azeem, Muhammad A1 - Jwayed, Suhib A. A1 - Al-Shehhi, Aaesha A1 - Tabassum, Attia A1 - Ayoub, Mohammed Akli A1 - Hetta, Helal F. A1 - Waheed, Yasir A1 - Iratni, Rabah A1 - Al-Dhaheri, Ahmed A1 - Muhammad, Khalid T1 - Current insights into immunology and novel therapeutics of atopic dermatitis JF - Cells N2 - Atopic dermatitis (AD) is one of the most prevalent inflammatory disease among non-fatal skin diseases, affecting up to one fifth of the population in developed countries. AD is characterized by recurrent pruritic and localized eczema with seasonal fluctuations. AD initializes the phenomenon of atopic march, during which infant AD patients are predisposed to progressive secondary allergies such as allergic rhinitis, asthma, and food allergies. The pathophysiology of AD is complex; onset of the disease is caused by several factors, including strong genetic predisposition, disrupted epidermal barrier, and immune dysregulation. AD was initially characterized by defects in the innate immune system and a vigorous skewed adaptive Th2 response to environmental agents; there are compelling evidences that the disorder involves multiple immune pathways. Symptomatic palliative treatment is the only strategy to manage the disease and restore skin integrity. Researchers are trying to more precisely define the contribution of different AD genotypes and elucidate the role of various immune axes. In this review, we have summarized the current knowledge about the roles of innate and adaptive immune responsive cells in AD. In addition, current and novel treatment strategies for the management of AD are comprehensively described, including some ongoing clinical trials and promising therapeutic agents. This information will provide an asset towards identifying personalized targets for better therapeutic outcomes. KW - atopic dermatitis KW - immune system KW - T cells KW - B cells KW - keratinocytes Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-241008 SN - 2073-4409 VL - 10 IS - 6 ER - TY - JOUR A1 - Alrefai, Hani A1 - Muhammad, Khalid A1 - Rudolf, Ronald A1 - Pham, Duong Anh Thuy A1 - Klein-Hessling, Stefan A1 - Patra, Amiya K. A1 - Avots, Andris A1 - Bukur, Valesca A1 - Sahin,, Ugur A1 - Tenzer, Stefan A1 - Goebeler, Matthias A1 - Kerstan, Andreas A1 - Serfling, Edgar T1 - NFATc1 supports imiquimod-induced skin inflammation by suppressing IL-10 synthesis in B cells JF - Nature Communications N2 - Epicutaneous application of Aldara cream containing the TLR7 agonist imiquimod (IMQ) to mice induces skin inflammation that exhibits many aspects of psoriasis, an inflammatory human skin disease. Here we show that mice depleted of B cells or bearing interleukin (IL)-10-deficient B cells show a fulminant inflammation upon IMQ exposure, whereas ablation of NFATc1 in B cells results in a suppression of Aldara-induced inflammation. In vitro, IMQ induces the proliferation and IL-10 expression by B cells that is blocked by BCR signals inducing NFATc1. By binding to HDAC1, a transcriptional repressor, and to an intronic site of the Il10 gene, NFATc1 suppresses IL-10 expression that dampens the production of tumour necrosis factor-α and IL-17 by T cells. These data indicate a close link between NFATc1 and IL-10 expression in B cells and suggest NFATc1 and, in particular, its inducible short isoform, NFATc1/αA, as a potential target to treat human psoriasis. KW - B cells KW - psoriasis KW - interleukins KW - inflammation Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-173053 VL - 7 ER - TY - JOUR A1 - Klein-Hessling, Stefan A1 - Rudolf, Ronald A1 - Muhammad, Khalid A1 - Knobeloch, Klaus-Peter A1 - Maqbool, Muhammad Ahmad A1 - Cauchy, Pierre A1 - Andrau, Jean-Christophe A1 - Avots, Andris A1 - Talora, Claudio A1 - Ellenrieder, Volker A1 - Screpanti, Isabella A1 - Serfling, Edgar A1 - Patra, Amiya Kumar T1 - A threshold level of NFATc1 activity facilitates thymocyte differentiation and opposes notch-driven leukaemia development JF - Nature Communications N2 - NFATc1 plays a critical role in double-negative thymocyte survival and differentiation. However, the signals that regulate Nfatc1 expression are incompletely characterized. Here we show a developmental stage-specific differential expression pattern of Nfatc1 driven by the distal (P1) or proximal (P2) promoters in thymocytes. Whereas, preTCR-negative thymocytes exhibit only P2 promoter-derived Nfatc1β expression, preTCR-positive thymocytes express both Nfatc1β and P1 promoter-derived Nfatc1α transcripts. Inducing NFATc1α activity from P1 promoter in preTCR-negative thymocytes, in addition to the NFATc1β from P2 promoter impairs thymocyte development resulting in severe T-cell lymphopenia. In addition, we show that NFATc1 activity suppresses the B-lineage potential of immature thymocytes, and consolidates their differentiation to T cells. Further, in the pTCR-positive DN3 cells, a threshold level of NFATc1 activity is vital in facilitating T-cell differentiation and to prevent Notch3-induced T-acute lymphoblastic leukaemia. Altogether, our results show NFATc1 activity is crucial in determining the T-cell fate of thymocytes. KW - acute lymphocytic leukaemia KW - transcription factors KW - lymphocyte differentiation Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-172974 VL - 7 ER - TY - JOUR A1 - Mahmood, Zafar A1 - Schmalzing, Marc A1 - Dörner, Thomas A1 - Tony, Hans-Peter A1 - Muhammad, Khalid T1 - Therapeutic Cytokine Inhibition Modulates Activation and Homing Receptors of Peripheral Memory B Cell Subsets in Rheumatoid Arthritis Patients JF - Frontiers in Immunology N2 - Memory B cells have known to play an important role in the pathogenesis of rheumatoid arthritis (RA). With the emergence of B cell-targeted therapies, the modulation of memory B cells appears to be a key therapeutic target. Human peripheral memory B cells can be distinguished based on the phenotypic expression of CD27 and IgD, characterizing the three major B cell subpopulations: CD27+IgD+ pre-switch, CD27+IgD- post-switch, and CD27-IgD- double-negative memory B cells. We evaluated different memory cell populations for activation markers (CD95 and Ki-67) and chemokine receptors (CXCR3 and 4) expressing B cells in active RA, as well as under IL6-R blockade by tocilizumab (TCZ) and TNF-α blockade by adalimumab (ADA). Memory B cells were phenotypically analyzed from RA patients at baseline, week 12, and week 24 under TCZ or ADA treatment, respectively. Using flow cytometry, surface expression of CD95, intracellular Ki-67, and surface expressions of CXCR3 and CXCR4 were determined. Compared with healthy donors (n = 40), the phenotypic analysis of RA patients (n = 80) demonstrated that all three types of memory B cells were activated in RA patients. Surface and intracellular staining of B cells showed a significantly higher percentage of CD95+ (p < 0.0001) and Ki-67+ (p < 0.0001) cells, with numerically altered CXCR3+ and CXCR4+ cells in RA. CD95 and Ki-67 expressions were highest in post-switch memory B cells, whereas CD19+CXCR3+ and CD19+CXCR4+ expressing cells were substantially higher in the pre-switch compartment. In all subsets of the memory B cells, in vivo IL-6R, and TNF-α blockade significantly reduced the enhanced expressions of CD95 and Ki-67. Based on our findings, we conclude that the three major peripheral memory B cell populations, pre-, post-switch, and double-negative B cells, are activated in RA, demonstrating enhanced CD95 and Ki-67 expressions, and varied expression of CXCR3 and CXCR4 chemokine receptors when compared with healthy individuals. This activation can be efficaciously modulated under cytokine inhibition in vivo. KW - B cells KW - inflammation KW - adalimumab KW - tocilizumab (IL-6 inhibitor) KW - memory B cells KW - rheumatoid arhritis Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-212380 SN - 1664-3224 VL - 11 ER - TY - JOUR A1 - Muhammad, Khalid A1 - Rudolf, Ronald A1 - Pham, Duong Anh Thuy A1 - Klein-Hessling, Stefan A1 - Takata, Katsuyoshi A1 - Matsushita, Nobuko A1 - Ellenrieder, Volker A1 - Kondo, Eisaku A1 -  Serfling, Edgar T1 - Induction of Short NFATc1/αA Isoform Interferes with Peripheral B Cell Differentiation JF - Frontiers in Immunology N2 - In lymphocytes, immune receptor signals induce the rapid nuclear translocation of preformed cytosolic NFAT proteins. Along with co-stimulatory signals, persistent immune receptor signals lead to high levels of NFATc1/αA, a short NFATc1 isoform, in effector lymphocytes. Whereas NFATc1 is not expressed in plasma cells, in germinal centers numerous centrocytic B cells express nuclear NFATc1/αA. When overexpressed in chicken DT40 B cells or murine WEHI 231 B cells, NFATc1/αA suppressed their cell death induced by B cell receptor signals and affected the expression of genes controlling the germinal center reaction and plasma cell formation. Among those is the Prdm1 gene encoding Blimp-1, a key factor of plasma cell formation. By binding to a regulatory DNA element within exon 1 of the Prdm1 gene, NFATc1/αA suppresses Blimp-1 expression. Since expression of a constitutive active version of NFATc1/αA interfered with Prdm1 RNA expression, LPS-mediated differentiation of splenic B cells to plasmablasts in vitro and reduced immunoglobulin production in vivo, one may conclude that NFATc1/αA plays an important role in controlling plasmablast/plasma cell formation. KW - B cells KW - DT40 cells KW - germinal center KW - NFATc1 KW - plasmablasts KW - plasma cells Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-197501 SN - 1664-3224 VL - 9 IS - 32 ER - TY - JOUR A1 - Rauschenberger, Tabea A1 - Schmitt, Viola A1 - Azeem, Muhammad A1 - Klein-Hessling, Stefan A1 - Murti, Krisna A1 - Grän, Franziska A1 - Goebeler, Matthias A1 - Kerstan, Andreas A1 - Klein, Matthias A1 - Bopp, Tobias A1 - Serfling, Edgar A1 - Muhammad, Khalid T1 - T cells control chemokine secretion by keratinocytes JF - Frontiers in Immunology N2 - The massive infiltration of lymphocytes into the skin is a hallmark of numerous human skin disorders. By co-culturing murine keratinocytes with splenic T cells we demonstrate here that T cells affect and control the synthesis and secretion of chemokines by keratinocytes. While pre-activated CD8\(^+\)T cells induce the synthesis of CXCL9 and CXCL10 in keratinocytes and keep in check the synthesis of CXCL1, CXCL5, and CCL20, keratinocytes dampen the synthesis of CCL3 and CCL4 in pre-activated CD8\(^+\)T cells. One key molecule is IFN-γ that is synthesized by CD8\(^+\)T cells under the control of NFATc1 and NFATc2. CD8\(^+\)T cells deficient for both NFAT factors are unable to induce CXCL9 and CXCL10 expression. In addition, CD8\(^+\)T cells induced numerous type I IFN-inducible “defense genes” in keratinocytes encoding the PD1 and CD40 ligands, TNF-α and caspase-1. The enhanced expression of type I IFN-inducible genes resembles the gene expression pattern at the dermal/epidermal interface in lichen planus, an inflammatory T lymphocyte-driven skin disease, in which we detected the expression of CXCL10 in keratinocytes in close vicinity to the infiltration front of T cells. These data reflect the multifaceted interplay of lymphocytes with keratinocytes at the molecular level. KW - chemokine KW - keratinocytes KW - IFN KW - lichen planus KW - T cells KW - Nfatc1 Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-195695 SN - 1664-3224 VL - 10 IS - 1917 ER - TY - JOUR A1 - Klein-Hessling, Stefan A1 - Muhammad, Khalid A1 - Klein, Matthias A1 - Pusch, Tobias A1 - Rudolf, Ronald A1 - Flöter, Jessica A1 - Qureischi, Musga A1 - Beilhack, Andreas A1 - Vaeth, Martin A1 - Kummerow, Carsten A1 - Backes, Christian A1 - Schoppmeyer, Rouven A1 - Hahn, Ulrike A1 - Hoth, Markus A1 - Bopp, Tobias A1 - Berberich-Siebelt, Friederike A1 - Patra, Amiya A1 - Avots, Andris A1 - Müller, Nora A1 - Schulze, Almut A1 - Serfling, Edgar T1 - NFATc1 controls the cytotoxicity of CD8\(^{+}\) T cells JF - Nature Communications N2 - Cytotoxic T lymphocytes are effector CD8\(^{+}\) T cells that eradicate infected and malignant cells. Here we show that the transcription factor NFATc1 controls the cytotoxicity of mouse cytotoxic T lymphocytes. Activation of Nfatc1\(^{-/-}\) cytotoxic T lymphocytes showed a defective cytoskeleton organization and recruitment of cytosolic organelles to immunological synapses. These cells have reduced cytotoxicity against tumor cells, and mice with NFATc1-deficient T cells are defective in controlling Listeria infection. Transcriptome analysis shows diminished RNA levels of numerous genes in Nfatc1\(^{-/-}\) CD8\(^{+}\) T cells, including Tbx21, Gzmb and genes encoding cytokines and chemokines, and genes controlling glycolysis. Nfatc1\(^{-/-}\), but not Nfatc2\(^{-/-}\) CD8\(^{+}\) T cells have an impaired metabolic switch to glycolysis, which can be restored by IL-2. Genome-wide ChIP-seq shows that NFATc1 binds many genes that control cytotoxic T lymphocyte activity. Together these data indicate that NFATc1 is an important regulator of cytotoxic T lymphocyte effector functions. KW - cytotoxic T cells KW - lymphocyte activation KW - signal transduction KW - gene regulation KW - immune cells KW - NFATc1 Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170353 VL - 8 IS - 511 ER - TY - JOUR A1 - Mahmood, Zafar A1 - Muhammad, Khalid A1 - Schmalzing, Marc A1 - Roll, Petra A1 - Dörner, Thomas A1 - Tony, Hans-Peter T1 - CD27-IgD- memory B cells are modulated by in vivo interleukin-6 receptor (IL-6R) blockade in rheumatoid arthritis JF - Arthritis Research & Therapy N2 - Introduction Enhanced B cell activity, particularly memory B cells have gained interest in evaluating response during therapies with biologics. CD27-IgD- double-negative (DN) B cells lacking the conventional memory marker CD27 are reported to be part of the memory compartment, however, only scarce data is available for rheumatoid arthritis (RA). We therefore focused on DN B cells in RA, studied their isotypes and modulation during interleukin-6 receptor (IL-6R) inhibition by tocilizumab (TCZ). Methods DN B cells were phenotypically analyzed from 40 RA patients during TCZ at baseline week 12, week 24 and 1 year. A single B cell polymerase chain reaction (PCR) approach was used to study Ig receptors, VH gene rearrangements and specific isotypes. Results Phenotypic analysis showed a significantly expanded population of DN B cells in RA which contain a heterogeneous mixture of IgG-, IgA- and IgM-expressing cells with a clear dominance of IgG+ cells. DN B cells carry rearranged heavy chain gene sequences with a diversified mutational pattern consistent with memory B cells. In contrast to tumor necrosis factor alpha (TNF-α) inhibition, a significant reduction in mutational frequency of BCR gene rearrangements at week 12, 24 and 1 year (P <0.0001) was observed by in vivo IL-6R inhibition. These changes were observed for all BCR isotypes IgG, IgA and IgM at week 12, 24 and 1 year (P <0.0001). IgA-RF, IgA serum level and IgA+ DN B cells decreased significantly (P <0.05) at week 12 and week 24 during TCZ. Patients with a good European League Against Rheumatism (EULAR) response to TCZ had less DN B cells at baseline as compared to moderate responders (P = 0.006). Univariate logistic regression analysis revealed that the frequency of DN B cells at baseline is inversely correlated to a subsequent good EULAR response (P = 0.024) with an odds ratio of 1.48 (95% confidence interval as 1.05 to 2.06). Conclusions In RA, the heterogeneous DN B cell compartment is expanded and dominated by IgG isotype. TCZ can modulate the mutational status of DN Ig isotype receptors over 1 year. Interestingly, the frequency of DN B cells in RA may serve as a baseline predictor of subsequent EULAR response to TCZ. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126506 VL - 17 IS - 61 ER - TY - JOUR A1 - Serfling, Edgar A1 - Rudolf, Ronald A1 - Busch, Rhoda A1 - Patra, Amiya K. A1 - Muhammad, Khalid A1 - Avots, Andris A1 - Andrau, Jean-Christophe A1 - Klein-Hessling, Stefan T1 - Architecture and expression of the Nfatc1 gene in lymphocytes N2 - In lymphocytes, the three NFAT factors NFATc1 (also designated as NFAT2), NFATc2 (NFAT1), and NFATc3 (NFAT4 or NFATx) are expressed and are the targets of immune receptor signals, which lead to a rapid rise of intracellular Ca++, the activation of phosphatase calcineurin, and to the activation of cytosolic NFATc proteins. In addition to rapid activation of NFAT factors, immune receptor signals lead to accumulation of the short NFATc1/αA isoform in lymphocytes which controls their proliferation and survival. In this mini-review, we summarize our current knowledge on the structure and transcription of the Nfatc1 gene in lymphocytes, which is controlled by two promoters, two poly A addition sites and a remote downstream enhancer. The Nfatc1 gene resembles numerous primary response genes (PRGs) induced by LPS in macrophages. Similar to the PRG promoters, the Nfatc1 promoter region is organized in CpG islands, forms DNase I hypersensitive sites, and is marked by histone tail modifications before induction. By studying gene induction in lymphocytes in detail, it will be important to elucidate whether the properties of the Nfatc1 induction are not only typical for the Nfatc1 gene but also for other transcription factor genes expressed in lymphocytes. KW - transcription KW - chromatin KW - induction KW - lymphocytes KW - Nfatc1 Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-112718 ER -