@article{GiampaoloWojcikSerflingetal.2017, author = {Giampaolo, Sabrina and W{\´o}jcik, Gabriela and Serfling, Edgar and Patra, Amiya K.}, title = {Interleukin-2-regulatory T cell axis critically regulates maintenance of hematopoietic stem cells}, series = {Oncotarget}, volume = {8}, journal = {Oncotarget}, number = {18}, doi = {10.18632/oncotarget.16377}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170947}, pages = {29625-29642}, year = {2017}, abstract = {The role of IL-2 in HSC maintenance is unknown. Here we show that Il2\(^{-/-}\) mice develop severe anomalies in HSC maintenance leading to defective hematopoiesis. Whereas, lack of IL-2 signaling was detrimental for lympho- and erythropoiesis, myelopoiesis was enhanced in Il2\(^{-/-}\) mice. Investigation of the underlying mechanisms of dysregulated hematopoiesis in Il2\(^{-/-}\) mice shows that the IL-2-T\(_{reg}\) cell axis is indispensable for HSC maintenance and normal hematopoiesis. Lack of T\(_{reg}\) activity resulted in increased IFN-γ production by activated T cells and an expansion of the HSCs in the bone marrow (BM). Though, restoring T\(_{reg}\) population successfully rescued HSC maintenance in Il2\(^{-/-}\) mice, preventing IFN-γ activity could do the same even in the absence of T\(_{reg}\) cells. Our study suggests that equilibrium in IL-2 and IFN-γ activity is critical for steady state hematopoiesis, and in clinical conditions of BM failure, IL-2 or anti-IFN-γ treatment might help to restore hematopoiesis.}, language = {en} } @article{SerflingRudolfBuschetal.2014, author = {Serfling, Edgar and Rudolf, Ronald and Busch, Rhoda and Patra, Amiya K. and Muhammad, Khalid and Avots, Andris and Andrau, Jean-Christophe and Klein-Hessling, Stefan}, title = {Architecture and expression of the Nfatc1 gene in lymphocytes}, doi = {10.3389/fimmu.2014.00021}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-112718}, year = {2014}, abstract = {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.}, language = {en} } @phdthesis{Patra2005, author = {Patra, Amiya Kumar}, title = {Modulation of the NFAT signaling pathway by protein kinase B (PKB) ; a perspective study in the context of thymocyte development and T cell function}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-13315}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2005}, abstract = {To analyze the role of protein kinase B(PKB)on developmental and functional aspects of T cells, we have generated transgenic mouse lines expressing a constitutively active form of PKB (myrPKB) in early stages of T cell development.Peripheral CD4+ T cells from PKB tg mice are hyperreactive, more efficient in producing th1 and th2 cytokines and show faster and CD28 co-stimulation independent cell cycle progression.Interestingly PKB tg T cells are resistant to CsA treatment in proliferation and cytokine production.Further analysis show PKB tg CD4+ T cells have a drastically reduced nuclear translocation of NFAT proteins and this is due to a direct interaction between PKB and NFAT. To study whether the negative regulatiopn of NFATs by PKB affects T cell development, we analyzed double tg mice expressing both, a constitutively active version of calcineurin (dCam) and myrPKB. dCam tg mice have a severe block in thymocyte development at the DN3 stage.But in the dCam/PKB double tg mice this developmental block is significantly rescued.This rescue of thymocyte development by PKB is due to the expression of RAG1 and subsequent TCRb chain expression. CsA treatment of neonatal thymic lobes from dCam mice restores normal thymocyte development, indicating involvement of NFATs in the severe block in dCam thymocyte development.Confocal studies clearly established that compared to dCam DN cells there is a significant reduction in the nuclear levels of NFATc1 and NFATc3 in dCam/PKB cells.Downregulation of nuclear NFAT levels by myrPKB thus seems to be an essential parameter in dCam cells to proceed with normal differentiation. In summary, the data from PKB tg peripheral CD4+ T cells and dCam/PKB double tg thymocytes clearly establish PKB as an important modulator of T cell development and function and PKB as a novel negative regulator of NFAT activation.}, subject = {T-Lymphozyt}, language = {en} } @article{KleinHesslingMuhammadKleinetal.2017, author = {Klein-Hessling, Stefan and Muhammad, Khalid and Klein, Matthias and Pusch, Tobias and Rudolf, Ronald and Fl{\"o}ter, Jessica and Qureischi, Musga and Beilhack, Andreas and Vaeth, Martin and Kummerow, Carsten and Backes, Christian and Schoppmeyer, Rouven and Hahn, Ulrike and Hoth, Markus and Bopp, Tobias and Berberich-Siebelt, Friederike and Patra, Amiya and Avots, Andris and M{\"u}ller, Nora and Schulze, Almut and Serfling, Edgar}, title = {NFATc1 controls the cytotoxicity of CD8\(^{+}\) T cells}, series = {Nature Communications}, volume = {8}, journal = {Nature Communications}, number = {511}, doi = {10.1038/s41467-017-00612-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170353}, year = {2017}, abstract = {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.}, language = {en} } @article{KleinHesslingRudolfMuhammadetal.2016, author = {Klein-Hessling, Stefan and Rudolf, Ronald and Muhammad, Khalid and Knobeloch, Klaus-Peter and Maqbool, Muhammad Ahmad and Cauchy, Pierre and Andrau, Jean-Christophe and Avots, Andris and Talora, Claudio and Ellenrieder, Volker and Screpanti, Isabella and Serfling, Edgar and Patra, Amiya Kumar}, title = {A threshold level of NFATc1 activity facilitates thymocyte differentiation and opposes notch-driven leukaemia development}, series = {Nature Communications}, volume = {7}, journal = {Nature Communications}, doi = {10.1038/ncomms11841}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172974}, year = {2016}, abstract = {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.}, language = {en} } @article{AlrefaiMuhammadRudolfetal.2016, author = {Alrefai, Hani and Muhammad, Khalid and Rudolf, Ronald and Pham, Duong Anh Thuy and Klein-Hessling, Stefan and Patra, Amiya K. and Avots, Andris and Bukur, Valesca and Sahin,, Ugur and Tenzer, Stefan and Goebeler, Matthias and Kerstan, Andreas and Serfling, Edgar}, title = {NFATc1 supports imiquimod-induced skin inflammation by suppressing IL-10 synthesis in B cells}, series = {Nature Communications}, volume = {7}, journal = {Nature Communications}, doi = {10.1038/ncomms11724}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-173053}, year = {2016}, abstract = {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.}, language = {en} } @article{BarahonadeBritoPatra2022, author = {Barahona de Brito, Carlotta and Patra, Amiya Kumar}, title = {NFAT factors are dispensable for the development but are critical for the maintenance of Foxp3\(^+\) regulatory T cells}, series = {Cells}, volume = {11}, journal = {Cells}, number = {9}, issn = {2073-4409}, doi = {10.3390/cells11091397}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-270668}, year = {2022}, abstract = {The transcription factors of the nuclear factor of activated T cell (NFAT) family play a crucial role in multiple aspects of T cell function. It has recently been reported that NFATs play an important role in the suppressive function of CD4\(^+\)CD25\(^+\)Foxp3\(^+\) regulatory T (T\(_{reg}\)) cells. In this study, we have investigated the role of NFATs in the thymic development of T\(_{reg}\) cells in mice. We show that NFAT factors are dispensable for the development of Foxp3\(^+\) T\(_{reg}\) cells in the thymus but are critical for the maintenance of both the phenotype and survival of T\(_{reg}\) cells in the thymus as well as in peripheral lymphoid organs. Specifically, the homeostasis of CD4\(^+\)CD25\(^+\)Foxp3\(^+\) but not the CD4\(^+\)CD25\(^-\)Foxp3\(^+\) fraction is severely perturbed when NFAT signaling is blocked, leading to a strongly reduced T\(_{reg}\) population. We underscored this intriguing effect of NFAT on CD4\(^+\)CD25\(^+\)Foxp3\(^+\) T\(_{reg}\) cells to the disruption of survival signals provided by interleukin 2 (IL-2). Accordingly, blocking T\(_{reg}\) cell death by abolishing the activity of pro-apoptotic Bcl-2 family member Bim, compensated for the survival defects induced due to a lack of NFAT-IL-2-IL-2R signaling. Inhibition of NFAT activity led to a strong reduction in the number of Foxp3\(^+\) T\(_{reg}\) cells; however, it did not influence the level of Foxp3 expression on an individual cell basis. In addition, we show a differential effect of IL-2 and IL-7 signaling on Foxp3\(^+\) T\(_{reg}\) versus CD4\(^+\)CD25\(^-\) T cell development, again underlining the dispensability of NFAT signaling in the development, but not in the maintenance of Foxp3\(^+\) T\(_{reg}\) cells.}, language = {en} } @article{BarahonadeBritoKleinHesslingSerflingetal.2022, author = {Barahona de Brito, Carlotta and Klein-Hessling, Stefan and Serfling, Edgar and Patra, Amiya Kumar}, title = {Hematopoietic stem and progenitor cell maintenance and multiple lineage differentiation is an integral function of NFATc1}, series = {Cells}, volume = {11}, journal = {Cells}, number = {13}, issn = {2073-4409}, doi = {10.3390/cells11132012}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-278809}, year = {2022}, abstract = {Hematopoietic stem and progenitor cell (HSPC) maintenance and the differentiation of various lineages is a highly complex but precisely regulated process. Multiple signaling pathways and an array of transcription factors influence HSPC maintenance and the differentiation of individual lineages to constitute a functional hematopoietic system. Nuclear factor of activated T cell (NFAT) family transcription factors have been studied in the context of development and function of multiple mature hematopoietic lineage cells. However, until now their contribution in HSPC physiology and HSPC differentiation to multiple hematopoietic lineages has remained poorly understood. Here, we show that NFAT proteins, specifically NFATc1, play an indispensable role in the maintenance of HSPCs. In the absence of NFATc1, very few HSPCs develop in the bone marrow, which are functionally defective. In addition to HSPC maintenance, NFATc1 also critically regulates differentiation of lymphoid, myeloid, and erythroid lineage cells from HSPCs. Deficiency of NFATc1 strongly impaired, while enhanced NFATc1 activity augmented, the differentiation of these lineages, which further attested to the vital involvement of NFATc1 in regulating hematopoiesis. Hematopoietic defects due to lack of NFATc1 activity can lead to severe pathologies such as lymphopenia, myelopenia, and a drastically reduced lifespan underlining the critical role NFATc1 plays in HSPC maintenance and in the differentaion of various lineages. Our findings suggest that NFATc1 is a critical component of the myriad signaling and transcriptional regulators that are essential to maintain normal hematopoiesis.}, language = {en} } @article{GiampaoloWojcikKleinHesslingetal.2019, author = {Giampaolo, Sabrina and W{\´o}jcik, Gabriela and Klein-Hessling, Stefan and Serfling, Edgar and Patra, Amiya K.}, title = {B cell development is critically dependent on NFATc1 activity}, series = {Cellular \& Molecular Immunology}, volume = {16}, journal = {Cellular \& Molecular Immunology}, doi = {10.1038/s41423-018-0052-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-233006}, pages = {508-520}, year = {2019}, abstract = {B cell development in bone marrow is a precisely regulated complex process. Through successive stages of differentiation, which are regulated by a multitude of signaling pathways and an array of lineage-specific transcription factors, the common lymphoid progenitors ultimately give rise to mature B cells. Similar to early thymocyte development in the thymus, early B cell development in bone marrow is critically dependent on IL-7 signaling. During this IL-7-dependent stage of differentiation, several transcription factors, such as E2A, EBF1, and Pax5, among others, play indispensable roles in B lineage specification and maintenance. Although recent studies have implicated several other transcription factors in B cell development, the role of NFATc1 in early B cell developmental stages is not known. Here, using multiple gene-manipulated mouse models and applying various experimental methods, we show that NFATc1 activity is vital for early B cell differentiation. Lack of NFATc1 activity in pro-B cells suppresses EBF1 expression, impairs immunoglobulin gene rearrangement, and thereby preBCR formation, resulting in defective B cell development. Overall, deficiency in NFATc1 activity arrested the pro-B cell transition to the pre-B cell stage, leading to severe B cell lymphopenia. Our findings suggest that, along with other transcription factors, NFATc1 is a critical component of the signaling mechanism that facilitates early B cell differentiation.}, language = {en} }