@article{RauschenbergerSchmittAzeemetal.2019, author = {Rauschenberger, Tabea and Schmitt, Viola and Azeem, Muhammad and Klein-Hessling, Stefan and Murti, Krisna and Gr{\"a}n, Franziska and Goebeler, Matthias and Kerstan, Andreas and Klein, Matthias and Bopp, Tobias and Serfling, Edgar and Muhammad, Khalid}, title = {T cells control chemokine secretion by keratinocytes}, series = {Frontiers in Immunology}, volume = {10}, journal = {Frontiers in Immunology}, number = {1917}, issn = {1664-3224}, doi = {10.3389/fimmu.2019.01917}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-195695}, year = {2019}, abstract = {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.}, 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} } @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{MurtiFenderGlatzleetal.2023, author = {Murti, Krisna and Fender, Hendrik and Glatzle, Carolin and Wismer, Rhoda and Sampere-Birlanga, Salvador and Wild, Vanessa and Muhammad, Khalid and Rosenwald, Andreas and Serfling, Edgar and Avots, Andris}, title = {Calcineurin-independent NFATc1 signaling is essential for survival of Burkitt lymphoma cells}, series = {Frontiers in Oncology}, volume = {13}, journal = {Frontiers in Oncology}, doi = {10.3389/fonc.2023.1205788}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-323103}, year = {2023}, abstract = {In Burkitt lymphoma (BL), a tumor of germinal center B cells, the pro-apoptotic properties of MYC are controlled by tonic B cell receptor (BCR) signals. Since BL cells do not exhibit constitutive NF-κB activity, we hypothesized that anti-apoptotic NFATc1 proteins provide a major transcriptional survival signal in BL. Here we show that post-transcriptional mechanisms are responsible for the calcineurin (CN) independent constitutive nuclear over-expression of NFATc1 in BL and Eµ-MYC - induced B cell lymphomas (BCL). Conditional inactivation of the Nfatc1 gene in B cells of Eµ-MYC mice leads to apoptosis of BCL cells in vivo and ex vivo. Inhibition of BCR/SYK/BTK/PI3K signals in BL cells results in cytosolic re-location of NFATc1 and apoptosis. Therefore, NFATc1 activity is an integrated part of tonic BCR signaling and an alternative target for therapeutic intervention in BL.}, language = {en} }