Search results for "Janus kinase 2"

Transcriptional and post-transcriptional regulation of iNOS expression in human chondrocytes

2009

Chondrocytes are important for the development and maintenance of articular cartilage. However, both in osteoarthritis (OA) and rheumatoid arthritis (RA) chondrocytes are involved in the process of cartilage degradation and synthesize important immunomodulatory mediators, including nitric oxide (NO) generated by the inducible NO synthase (iNOS). To uncover the role of iNOS in the pathomechanisms of OA and RA, we analyzed the regulation of iNOS expression using immortalized human chondrocytes as a reproducible model. In C-28/I2 chondrocytes, iNOS expression was associated with the expression of the chondrocyte phenotype. Peak induction by a cytokine cocktail occurred between 6 and 8h and dec…

Acquired IFNγ resistance impairs anti-tumor immunity and gives rise to T-cell-resistant melanoma lesions

2016

Melanoma treatment has been revolutionized by antibody-based immunotherapies. IFNγ secretion by CD8+ T cells is critical for therapy efficacy having anti-proliferative and pro-apoptotic effects on tumour cells. Our study demonstrates a genetic evolution of IFNγ resistance in different melanoma patient models. Chromosomal alterations and subsequent inactivating mutations in genes of the IFNγ signalling cascade, most often JAK1 or JAK2, protect melanoma cells from anti-tumour IFNγ activity. JAK1/2 mutants further evolve into T-cell-resistant HLA class I-negative lesions with genes involved in antigen presentation silenced and no longer inducible by IFNγ. Allelic JAK1/2 losses predisposing to …

Constitutive activation of JAK2 in mammary epithelium elevates Stat5 signalling, promotes alveologenesis and resistance to cell death, and contribute…

2011

Signalling through the janus kinase (JAK)/signal transducer and activator of transcription (Stat) pathway is required at different stages of mammary gland development, and this pathway is frequently hyper-activated in cancer, including tumours of the breast. Stats 3, 5 and 6 have important roles in the differentiation and survival of mammary alveolar cells, but somewhat paradoxically, both Stat3 and 5 can have oncogenic activity in the mammary gland. Constitutive activation of JAK2 could be anticipated to result in hyper-activation of Stats 1, 3, 5 and 6 with concomitant cell transformation, although the outcome is difficult to envisage, particularly since Stats 3 and 5 play opposing roles …

Concordance of assays designed for the quantification of JAK2V617F: a multicenter study

2008

Background Many different techniques have been designed for the quantification of JAK2 V617F allelic burden, sometimes producing discrepant results. Design and Methods JAK2 V617F quantification techniques were compared among 16 centers using 11 assays based on quantitative polymerase chain reaction (with mutation-specific primers or probes, or fluorescent resonance energy transfer/melting curve analysis), allele-specific polymerase chain reaction, conventional sequencing or pyrosequencing. Results A first series of blinded samples (granulocyte DNA, n=29) was analyzed. Seven assays (12 centers) reported values inside the mean±2SD; the mean coefficient of variation was 31%. Sequencing techniq…

Germline JAK2 L611S mutation in a child with thrombocytosis

2018

Wild-type JAK2 secondary acute erythroleukemia developing after JAK2-V617F-mutated primary myelofibrosis.

2009

A 54-year-old female patient developed acute erythroleukemia after an 8-year course of primary myelofibrosis. The latter harbors the JAK2-V617F mutation and was treated with hydroxyurea and anagrelide. A bone marrow trephine biopsy disclosed 2 morphologically distinct areas of chronic primary myelofibrosis and acute erythroleukemia. Microdissection and a separate molecular pathological analysis was performed. Although the activating JAK2-V617F mutation was not maintained in blasts of acute erythroleukemia, it was detectable in the chronic phase of primary myelofibrosis, indicating that this mutation did not play a role in the leukemic transformation of erythroid cells.

The Role of JAK/STAT Molecular Pathway in Vascular Remodeling Associated with Pulmonary Hypertension

2021

Pulmonary hypertension is defined as a group of diseases characterized by a progressive increase in pulmonary vascular resistance (PVR), which leads to right ventricular failure and premature death. There are multiple clinical manifestations that can be grouped into five different types. Pulmonary artery remodeling is a common feature in pulmonary hypertension (PH) characterized by endothelial dysfunction and smooth muscle pulmonary artery cell proliferation. The current treatments for PH are limited to vasodilatory agents that do not stop the progression of the disease. Therefore, there is a need for new agents that inhibit pulmonary artery remodeling targeting the main genetic, molecular,…

Presence of calreticulin mutations in JAK2-negative polycythemia vera

2014

Abstract Calreticulin (CALR) mutations have recently been reported in JAK2- and MPL-negative Myeloproliferative Neoplasms (MPN), particularly essential thrombocythemia (ET) and primary myelofibrosis (PMF).The clinical course of sporadic CALR-mutated patients seems to be more indolent than that of JAK2-mutated patients. In contrast, no CALR mutation has been found in the 647 published cases of Polycythemia Vera (PV) patients tested. Consequently, CALR mutations were considered exclusive to JAK2 and MPL mutations. Since 98% of PV patients harbor a JAK2 mutation (mostly the V617F mutation in exon 14 and more rarely, in exon 12), the absence of CALR mutations in PV seemed logical. Here, we desc…

Endothelial transcriptomic changes induced by oxidized low density lipoprotein disclose an up-regulation of Jak-Stat pathway.

2015

Oxidized low density lipoproteins (oxLDLs) act as an etiological factor in the development of atherosclerosis by modifying the biological properties of endothelial cells through mechanisms of vascular inflammation. To deepen the oxLDL changes at cellular level, a transcriptomic analysis of human umbilical artery endothelial cells (HUAECs) treated with oxLDL was performed to identify the modified signaling pathways. Total RNA was isolated from HUAECs treated with oxLDL (100 μg/ml). Gene expression analysis was carried out using Affymetrix oligonucleotide microarrays. Biological pathway analysis was performed using Ingenuity Pathway Analysis software. Microarray assay demonstrated that oxLDL …

Fludarabine prevents smooth muscle proliferation in vitro and neointimal hyperplasia in vivo through specific inhibition of STAT-1 activation.

2007

Drug-eluting stents are increasingly used to reduce in-stent restenosis and adverse cardiac events after percutaneous coronary interventions. However, the race for the ideal drug-eluting stent is still on, with special regard to the best stent-coating system and the most effective and less toxic drug. Fludarabine, a nucleoside analog, has both anti-inflammatory and antiproliferative cellular effects. The aim of the present study was to assess the cellular and molecular effects of fludarabine on vascular smooth muscle cell (VSMC) growth in vitro and in vivo and the feasibility and efficacy of a fludarabine-eluting stent. To study the biomolecular effects of fludarabine on VSMC proliferation…