Project description:TCRαβ CD8 large granular lymphocyte (LGL) leukemia is a rare heterogeneous hematological disorder with a chronic disease course that mostly affects elderly. It is generally accepted that LGL cells arise as a consequence of chronic antigenic stimulation and inflammation and thrive because of dysregulation of mainly the STAT3 but also to some extent the ERK pathway, which are constitutively activated. In approximately 40% of patients this is due to STAT3 activating mutations, but for the other 60% it remains to be elucidated, why the STAT3 pathway is chronically activated. miRNAs are one of the most potent regulators in health and disease and are also linked with various leukemias. Therefore, we hypothesized that aberrant miRNA expression could contribute to dysregulation of the STAT3 pathway. miRNA sequencing in LGL leukemia cases and aged-matched healthy control TEMRA cells revealed overexpression of miRNA181a. Furthermore, gene set enrichment analysis (GSEA) of miRNA181a implicated its involvement in the STAT3 and ERK1/2 pathways. Phosphoflow analysis of STAT3, ERK1/2 in miR181a-transfected human CD8 T cells revealed that miR181a overexpression results in STAT3 and ERK1/2 phosphorylation. By using TL1, a human T-LGL cell line model, we have now established that miR181a is the common actor in T-LGL leukemia, driving STAT3 activation by SOCS3 inhibition in LGL leukemia patients. Additionally, miR181a induces ERK1/2 phosphorylation by inhibition of DUSP6. Taken together, our data show that miR181a is the missing link to explain why STAT3-unmutated patients show hyperactive STAT3.
Project description:TCRαβ CD8 large granular lymphocyte (LGL) leukemia is a rare heterogeneous hematological disorder with a chronic disease course that mostly affects elderly. It is generally accepted that LGL cells arise as a consequence of chronic antigenic stimulation and inflammation and thrive because of dysregulation of mainly the STAT3 but also to some extent the ERK pathway, which are constitutively activated. In approximately 40% of patients this is due to STAT3 activating mutations, but for the other 60% it remains to be elucidated, why the STAT3 pathway is chronically activated. miRNAs are one of the most potent regulators in health and disease and are also linked with various leukemias. Therefore, we hypothesized that aberrant miRNA expression could contribute to dysregulation of the STAT3 pathway. miRNA sequencing in LGL leukemia cases and aged-matched healthy control TEMRA cells revealed overexpression of miRNA181a. Furthermore, gene set enrichment analysis (GSEA) of miRNA181a implicated its involvement in the STAT3 and ERK1/2 pathways. Phosphoflow analysis of STAT3, ERK1/2 in miR181a-transfected human CD8 T cells revealed that miR181a overexpression results in STAT3 and ERK1/2 phosphorylation. By using TL1, a human T-LGL cell line model, we have now established that miR181a is the common actor in T-LGL leukemia, driving STAT3 activation by SOCS3 inhibition in LGL leukemia patients. Additionally, miR181a induces ERK1/2 phosphorylation by inhibition of DUSP6. Taken together, our data show that miR181a is the missing link to explain why STAT3-unmutated patients show hyperactive STAT3.
Project description:To identify Lgl binding proteins, we purified Lgl-containing protein complexes from cultured Drosophila S2 cells, using the single-step streptavidin purification from stable cell lines expressing SBP-tagged Lgl, followed by nanoLC-MS/MS analysis of the interactors. This study revealed the binding of Lgl to Vap33, which we further connected to the function of the vacuolar ATPase and regulation of Notch signaling.
Project description:Recent studies suggest the potential involvement of common antigenic stimuli on the ontogeny of monoclonal TCRalphabeta+/CD4+/NKa+/CD8-/+dim T-large granular lymphocyte (LGL) lymphocytosis. Since healthy individuals show (oligo)clonal expansions of hCMV-specific TCRVbeta+/CD4+/cytotoxic/memory T-cells, we investigate the potential involvement of hCMV in the origin and/or expansion of monoclonal CD4+ T-LGL. A detailed characterization of those genes that underwent changes in T-LGL cells responding to hCMV was performed by microarray gene expression profile (GEP) analysis.
Project description:We used microarrays to expression profile peripheral blood mononuclear cells (PBMCs) from LGL leukemia patients and control subjects to identify survival pathways that render leukemic LGL resistant to activation induced cell death. Keywords: granular lymphocyte leukemia, PBMC
Project description:Single channel custom oligonucleotide array of 147 microRNAs to detect changes in expression of a lgl-hypomorph mutant versus wild-type 0, 3, and 5 day old 3rd instar lgl-hypomorph larvae were compared to 0 day 3rd instar wild-type larvae to test for differences in microRNA expression
Project description:SASH3 (SAM [Sterile Alpha Motif] and SH3 domain-containing 3) is an X-linked gene that encodes a putative signaling adaptor protein expressed in lymphocyte cytoplasm and nucleus. Previously, we reported SASH3 mutations in 4 patients presenting with opportunistic infections and leukopenia. T cells proliferated poorly and had increased apoptosis when stimulated with mitogens. One patient, designated P1, had a SASH3 protein-positive phenotype with a unique p.R347C missense variant, whereas the other 3 patients were SASH3 protein-negative. P1 presented with massive cutaneous wart burden and panlymphopenia, low serum IgM, severe neutropenia and CD8+CD57+ large granular lymphocyte leukemia (LGL). To study direct causal effects of p.R347C, we developed by CRISPR-Cas9 gene editing a SASH3R347 knock-in (KI) mouse. Phenocopying the patient, the mice had B, T and NK cell lymphopenia in blood. However, LGL and neutropenia did not spontaneously develop, even in aged mice. CD8+ T cell (particularly naïve) lymphopenia was the most prominent feature, and was associated with increased apoptosis and proliferation but not defective CD8+ T cell development, maturation or distribution. SASH3 associated with chromatin, and the transcriptome of naïve SASH3R347 KI CD8+ T cells had upregulation of several signaling genes. At follow-up, P1’s clinical status had spontaneously improved with complete regression of warts, markedly reduced LGL cells and resolution of severe neutropenia. Thus, SASH3R347 directly causes panlymphopenia but not LGL in mice. Neutropenia in the patient is likely to be secondary to LGL, whose pathogenesis remains undefined in SASH3 deficiency.