Janus-activated Kinase/signal Transducers And Activators Of Transcription Research Articles

Long non-coding RNA FOXP4-AS1 is a prognostic biomarker and associated with immune infiltrates in ovarian serous cystadenocarcinoma.

Background:FOXP4-AS1 expression participates in multiple signal pathways and has been previously reported in colorectal cancer, cervical cancer, and other cancer cells. However, its role on prognosis and immune infiltrates in ovarian serous cystadenocarcinoma (OVs) remains unclear. The purpose of our study was to investigate the expression of FOXP4-AS1 in OVs and its association with immune infiltrates, and determined its prognostic roles in OVs.Methods:Using The Cancer Genome Atlas (TCGA) database, we retrieved FOXP4-AS1 expression and clinical information for 376 patients with OVs. Wilcoxon rank sum test was used to compare the expression of FOXP4-AS1 in OVs and normal ovarian tissue. Logistic regression was used to analyze the relationship between clinicopathologic features and FOXP4-AS1. Gene Set Enrichment Analysis (GSEA), and single sample Gene Set Enrichment Analysis (ssGSEA) was conducted to investigate the enrich pathways and functions and quantify the extent of immune cells infiltration for FOXP4-AS1. Kaplan–Meier method was used to generate survival curves, and Cox regression was used to analyze the relationship between FOXP4-AS1 and survival rate.Results:High FOXP4-AS1 expression was significantly correlated with tumor FIGO stage (P = .026). Multivariate survival analysis showed that FOXP4-AS1was an independent prognostic marker for overall survival (OS; hazard ratio [HR]: 0.638; 95% confidence interval [CI]:0.467–0.871; P = .001) and disease-specific survival (DSS; HR: 0.649; CI: 0.476–0.885; P = .006). GSEA showed that High FOXP4-AS1 expression may active programmed cell death 1 (PD-1) signaling, the cytotoxic T lymphocyte-associated antigen-4 (CTLA4) pathway, the B cell receptor signaling pathway, apoptosis, fibroblast growth factor receptor (FGFR) signaling, and the Janus-activated kinase signal transducers and activators of transcription (JAK-STAT) signaling pathway. FOXP4-AS1 expression was negatively correlated with markers of immune cells, including aDC, cytotoxic cells and neutrophils.Conclusion:High FOXP4-AS1 expression has the potential to be a prognostic molecular marker of favorable survival in OVs.

New Aspects of VEGF, GABA, and Glutamate Signaling in the Neocortex of Human Temporal Lobe Pharmacoresistant Epilepsy Revealed by RT-qPCR Arrays.

In the epilepsy spectrum, temporal lobe epilepsy (TLE) is the most common and devastating focal and symptomatic epilepsy form in adults, where more than 30% of patients develop pharmacoresistance. It is not fully understood how the gene expression contributes to establishing an epileptic phenotype. Cerebrovascular remodeling directed by VEGF (vascular endothelial growth factor) signaling might modulate the synaptic neurotransmission in the epileptic brain. To address this question, the gene expression was profiled in biopsies of the temporal cortex from diagnosed patients with pharmacoresistant TLE that underwent surgical resection to seizure control. One hundred sixty-eight genes related to VEGF signaling and GABA and glutamate neurotransmissions were evaluated. Genes related to downstream signaling -phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinases (MAPK), and Janus-activated kinase/signal transducer and activator of transcription (JAK/STAT) pathways- and neurotransmitters metabolism were evaluated too. Thirty-nine genes were upregulated. The genes encoding for G protein q polypeptide, serine racemase, gephyrin, and glutamate/cystine antiporter system xCT appeared as novel upregulated genes in the pharmacoresistant TLE. ClueGO, a Cytoscape plugin, was used to build a gene network associated using Gene Ontology (GO) terminology. Enrichment analysis by ClueGO retrieves that positive regulation of endothelial cell proliferation, nerve development, and neuronal apoptosis were over-represented categories. In conclusion, VEGF signaling is confirmed as a relevant mediator in the pharmacoresistant TLE. In addition, the enrichment analysis applied to differentially expressed genes suggests new pharmacological targets to be assessed in the treatment of pharmacoresistant TLE. Results make up an approximation to better understand the epileptic brain and complement the available data.

High-throughput screening for small molecule inhibitors of the type-I interferon signaling pathway

Interferons (IFNs) are cytokines with fundamental roles in resistance to infections, cancer and other diseases. Type-I IFNs, interferon α (IFN-α) and interferon β (IFN-β), act through a shared receptor complex (IFNAR) comprised of IFNAR1 and IFNAR2 subunits. Binding of type-I IFN to IFNAR1 will robustly activate Janus activated kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway. Aberrant activation of the type-I IFN response results in a spectrum of disorders called interferonopathies. The purpose of this research is to develop an assay for high-throughput screening (HTS) of small molecule inhibitors of the type-I IFN signaling pathway. Inhibition of type-I IFN signaling can be beneficial in terms of therapeutic use and understanding the underlying mechanism of action. We report here a HTS campaign with the secreted embryonic alkaline phosphatase (SEAP) reporter gene assay against 32,000 compounds which yielded 25 confirmed hits. These compounds were subsequently characterized for their cytotoxicity, effects on STAT phosphorylation and activities in IFN regulatory factor (IRF) transcription.

Therapeutics targeting innate immune/inflammatory responses through the interleukin-6/JAK/STAT signal transduction pathway in patients with cancer

Over the last 15years, there has been an evolution in the thinking of how tumors grow and disseminate: from the earlier work where it was considered that the intrinsic characteristics of the tumor largely determined the process to more recent work where local and systemic inflammatory responses play a key role in disease progression and survival in patients with cancer. Although the immune/inflammatory responses to cancer are complex, it is clear that targeting the host immune/inflammatory responses (in particular, innate/humoral responses) has considerable potential to improve outcomes in patients with a variety of common solid tumors. There are a wide variety of agents from the nonselective glucocorticoids to the selective Janus Activated Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) inhibitors that has considerable therapeutic potential. They may be considered to act through a main signal transduction mechanism, the interleukin-6/JAK/STAT pathway. This work heralds a new era in which it will be important not only to treat the tumor but also to treat the host, so called oncoimmunology.

Survival Response of Hippocampal Neurons under Low Oxygen Conditions Induced by Hippophae rhamnoides is Associated with JAK/STAT Signaling

Janus activated kinase/signal transducers and activators of transcription (JAK/STATs) pathway are associated with various neuronal functions including cell survival and inflammation. In the present study, it is hypothesized that protective action of aqueous extract of Hippophae rhamnoides in hippocampal neurons against hypoxia is mediated via JAK/STATs. Neuronal cells exposed to hypoxia (0.5% O2) display higher reactive oxygen species with compromised antioxidant status compared to unexposed control cells. Further, these cells had elevated levels of pro-inflammatory cytokines; tumor necrosis factor α and interleukin 6 and nuclear factor κappa B. Moreover, the expression of JAK1 was found to be highly expressed with phosphorylation of STAT3 and STAT5. Cells treated with JAK1, STAT3 and STAT5 specific inhibitors resulted in more cell death compared to hypoxic cells. Treatment of cells with extract prevented oxidative stress and inflammatory response associated with hypoxia. The extract treated cells had more cell survival than hypoxic cells with induction of JAK1 and STAT5b. Cells treated with extract having suppressed JAK1 or STAT3 or STAT5 expression showed reduced cell viability than the cell treated with extract alone. Overall, the findings from these studies indicate that the aqueous extract of Hippophae rhamnoides treatment inhibited hypoxia induced oxidative stress by altering cellular JAK1, STAT3 and STAT5 levels thereby enhancing cellular survival response to hypoxia and provide a basis for possible use of aqueous extract of Hippophae rhamnoides in facilitating tolerance to hypoxia.

Changing partners at the dance

Differential use of cellular and molecular components shapes immune responses, but understanding of how these are regulated to promote defense and health during infections is still incomplete. Examples include signaling from members of the Janus activated kinase-signal transducer and activator of transcription (JAK-STAT) cytokine family. Following receptor stimulation, individual JAK-STAT cytokines have preferences for particular key STAT molecules to lead to specific cellular responses. Certain of these cytokines, however, can conditionally activate alternative STATs as well as elicit pleiotropic and paradoxical effects. Studies examining basal and infection conditions are revealing intrinsic and induced cellular differences in various intracellular STAT concentrations to control the biological consequences of cytokine exposure. The system can be likened to changing partners at a dance based on competition and relative availability, and sets a framework for understanding the particular conditions promoting subset biological functions of cytokines as needed during evolving immune responses to infections.

Leptin and cardiovascular diseases

1. Leptin is a 16-kDa hormone, synthesized primarily by adipocyte, which acts as a key factor for maintenance of energy homeostasis in central and peripheral tissues. In most obese individuals, serum leptin levels are increased and correlate with the individual's body mass index. 2. Abundant investigations ranging from clinical and animal model studies to in vitro analyses show that leptin plays a pivotal role in obesity-related cardiovascular diseases (CVD). Hyperleptinaemia has been confirmed to be a predictor of acute cardiovascular events. However, some studies have shown that leptin has a cardioprotective effect in leptin-deficient models. These data suggest the influences of leptin on the pathophysiology of cardiovascular diseases are complex and not completely understood. 3. In the present review, we summarize the major leptin signalling pathways, including Janus-activated kinase/signal transducers and activators of transcription (Jak/STAT), mitogen-activated protein kinases (MAPK), and phosphatidylinositol 3-kinase (PI-3K) signalling pathways, and analyse the probable mechanisms of selective leptin resistance. We then provide a detailed review of the effects of leptin on the cardiovascular system, including sympathoactivation, oxidative stress, vascular inflammation, endothelial dysfunction, vascular cell proliferation, cardiomyocytes hypertrophy, as well as fatty acid metabolism, all of which contribute to the pathogenesis of cardiovascular diseases (e.g. ischaemic heart disease). The central premise of this review is to elucidate the mechanisms by which leptin affects the cardiovascular function and provide insight into obesity-related CVD.

Insulin-Like Growth Factor-I Deficiency in Children with Growth Hormone Insensitivity

Growth hormone (GH) acts directly at the growth plate and through the production of insulin-like growth factor (IGF)-I. At least 50% of the hormone circulates bound to GH binding protein, and its secretion is controlled by growth hormone-releasing hormone and somatostatin. Once GH binds to two GH receptors, the janus activated kinase/signal transducers and activators of transcription (JAK/STAT) protein pathway is activated, resulting in the production of IGF-I. Serum IGF-I is produced predominantly in the liver and circulates in a 140 kDa complex, along with its binding protein, IGF binding protein 3, and acid-labile protein. Recombinant human (rh) IGF-I (mecasermin) is approved by the US FDA and the European Medicines Agency for the treatment of patients with severe primary IGF deficiency or for patients with GH1 gene deletion who have developed neutralizing antibodies to GH. It has been shown to increase growth velocity in children with either condition. In the past, there have been adverse events, particularly hypoglycemia, reported with the administration of mecasermin. However, a recent report of long-term therapy with mescasermin in children with severe IGF-I deficiency has concluded that although adverse events are common, they are rarely severe enough to interrupt or modify treatment. The serum half-life of mecasermin is shorter in patients with GH insensitivity syndrome and low serum levels of its binding protein, the insulin-like growth factor binding protein (IGFBP)-3 and acid-labile subunit, compared with the serum half-life in normal volunteers or in patients with an IGF1 gene deletion who have normal levels of IGFBP-3. Mecasermin rinfabate, a complex of rhIGF-I and rhIGFBP-3, appears to prolong the serum half-life and might counteract acute adverse events, particularly hypoglycemia, associated with the administration of mescasermin. Mecasermin rinfabate, however, is no longer available in the USA or Europe for treating conditions involving short stature, because of a legal requirement. Mecasermin has been shown to be effective in increasing height velocity and adult height in patients with severe GH resistance and in IGF1 gene deletion. There has been some interest in using mecasermin to treat patients with partial GH resistance or idiopathic short stature. At the present time, the data are insufficient to make this recommendation.

Interferon-sensitive response element (ISRE) is mainly responsible for IFN-α-induced upregulation of programmed death-1 (PD-1) in macrophages

Programmed death-1 (PD-1), an immunoinhibitory receptor, is upregulated in T cells, B cells, NKT cells, and monocytes upon activation. More specifically, T-cell-associated PD-1 is critically important for maintaining peripheral tolerance through the PD-1-B7-H1 pathway. However, the physiological role of macrophage-associated PD-1 remains unclear. We addressed the molecular mechanism underlying the regulation of PD-1 expression on macrophages in response to IFN-alpha. Based on a luciferase assay using promoter constructs, we found that the promoter region located between -1090 and -1105 nucleotides from the translational start site is essential for PD-1 expression. Electrophoretic mobility-shift assay and site-directed mutagenesis revealed that interferon-sensitive responsive element (ISRE) and STAT1 and STAT2 are primarily responsible for the constitutive expression of PD-1, as well as for the IFN-alpha-mediated upregulation of PD-1. In addition, AG490, a Janus-activated kinase/signal transducer and activator of transcription (JAK/STAT) inhibitor, markedly abolished the responsiveness of bone marrow-derived macrophages (BMM) to IFN-alpha. Our findings support the essential roles of ISRE, STAT1, and STAT2 in the regulation of constitutive and IFN-alpha-mediated PD-1 expression in macrophages.

Antiapoptotic properties of erythropoiesis-stimulating proteins in models of cisplatin-induced acute kidney injury

Erythropoietin (Epo) induces erythrocytosis by suppressing erythroid progenitor cell apoptosis through the Janus-activated kinase-signal transducers and activators of transcription (JAK-STAT) pathway. Since apoptosis contributes to cisplatin (CP)-induced nephrotoxicity and Epo receptors (EpoR) are expressed in the kidney, we examined the role of antiapoptosis in recombinant human erythropoietin (rHuEpo)-mediated renal protection. In human renal proximal tubular epithelial (RPTE) cells in culture, rHuEpo, but not inactive rHuEpo (I-rHuEpo), the receptor-binding sites of which are mutated, caused a significant reduction in CP-induced apoptosis at > or = 100 U/ml. rHuEpo, but not I-rHuEpo, increased STAT5 and Akt/PKB phosphorylation, demonstrating functional EpoR expression on RPTE cells. Furthermore, the JAK2 inhibitor tyrphostin AG-490 attenuated rHuEpo protection, suggesting a role of the JAK-STAT pathway in rHuEpo-mediated antiapoptosis. In rats, intravenous administration of 5,000 U/kg rHuEpo, but not an equivalent peptide mass of I-rHuEpo, before a single 5.5 mg/kg iv injection of CP, significantly increased hematocrit (Hct) and reduced the CP-induced increase in serum creatinine. Serum creatinine on day 4 was 3.4 +/- 0.3, 1.9 +/- 0.3, and 3.5 +/- 0.4 mg/dl in the CP, CP + rHuEpo, and CP + I-rHuEpo groups, respectively. Similarly, darbepoietin-alpha (DA), a hyperglycosylated analog of rHuEpo with prolonged in vivo activity when injected at 25 microg/kg iv before CP, significantly increased Hct and reduced serum creatinine. Renal clearance studies based on glomerular filtration rate and renal blood flow confirmed the significant renal protection by DA against CP. Tubular apoptosis and necrosis were significantly reduced in the kidneys of the CP + DA vs. the CP + saline group. Moreover, the equalization of Hct by venesection did not abrogate the DA-mediated renal protection. Administration of DA 48 h after CP injection also conferred significant renal protection. Thus our experiments confirm a role for erythropoiesis-stimulating proteins, including the new analog DA, in limiting CP-induced nephrotoxicity and suggest that antiapoptosis via the Epo-EpoR interaction is an important mechanism for renal protection.

MUC1 Oncoprotein Promotes Refractoriness to Chemotherapy in Thyroid Cancer Cells

Overexpression of MUC1 oncoprotein is frequently observed in cancer and contributes to confer resistance to genotoxic agents. Papillary, follicular, and anaplastic thyroid carcinomas are the three forms of thyroid epithelial cancer. Anaplastic tumors are less differentiated and extremely aggressive, characterized by a poor prognosis. Little is known about the role of MUC1 in thyroid cancer. We recently showed that autocrine production of interleukin (IL)-4 and IL-10 controls thyroid cancer cell survival, growth, and resistance to chemotherapy through activation of Janus-activated kinase/signal transducers and activators of transcription (JAK/STAT) and phosphatidylinositide 3'-OH kinase (PI3K)/Akt pathways. In the present study, we showed that MUC1 COOH-terminal subunit (MUC1-C) is overexpressed in all the histologic variants of thyroid cancer cells and localizes to mitochondria where it interferes with the release of mitochondrial proapoptotic proteins. Moreover, IL-4 and IL-10 promote the increase of MUC1-C expression levels in normal thyroid cells, whereas blockage of both cytokines or neutralization of JAK/STAT and PI3K/Akt pathways through the exogenous expression of SOCS-1 and Akt(K179M) leads to a significant decrease of MUC1-C in primary thyroid cancer cells. Interestingly, down-regulation of MUC1 expression by direct targeting with RNA interference sensitizes anaplastic thyroid cancer cells to chemotherapy-induced apoptosis in vitro. Thus, MUC1 is a main component of the survival network acting in thyroid cancer and could be considered a key molecular target for sensitizing cancer cells to conventional or novel treatments.

Dormant Tumor Cells Develop Cross-Resistance to Apoptosis Induced by CTLs or Imatinib Mesylate via Methylation of Suppressor of Cytokine Signaling 1

In the BCR/ABL DA1-3b mouse model of acute myelogenous leukemia, dormant tumor cells may persist in the host in a state of equilibrium with the CD8(+) CTL-mediated immune response by actively inhibiting T cells. Dormant tumor cells also show a progressive decrease of suppressor of cytokine signaling 1 (SOCS1) gene expression and a deregulation of the Janus-activated kinase/signal transducers and activators of transcription (JAK/STAT) pathway due to methylation of the SOCS1 gene. Dormant tumor cells were more resistant to apoptosis induced by specific CTLs, but resistance decreased when SOCS1 expression was restored via demethylation or gene transfer. AG490 JAK2 inhibitor decreased the resistance of dormant tumor cells to CTLs, but MG132 proteasome inhibitor was effective only in SOCS1-transfected cells. Thus, SOCS1 regulation of the JAK/STAT pathways contributes to the resistance of tumor cells to CTL-mediated killing. Resistance of dormant tumor cells to apoptosis was also observed when induced by irradiation, cytarabine, or imatinib mesylate, but was reduced by SOCS1 gene transfer. This cross-resistance to apoptosis was induced by interleukin 3 (IL-3) overproduction by dormant tumor cells and was reversed with an anti-IL-3 antibody. Thus, tumor cells that remain dormant for long periods in the host in spite of a specific CTL immune response may deregulate their JAK/STAT pathways and develop cross-resistance to various treatments through an IL-3 autocrine loop. These data suggest possible new therapeutic targets to eradicate dormant tumor cells.

Interferon-γ enhances superoxide production in human mesangial cells via the JAK–STAT pathway

Immune reactive cytokines, such as interferon (IFN)-gamma, have multiple effects in glomerulonephritis. Superoxide anions (O(2)(-)), which are associated with the progression of glomerulonephritis, are mainly generated by nicotinamide adenine dinucleotide phosphate (reduced form) NAD(P)H oxidases. We determined the effects of IFN-gamma on O(2)(-) production, phosphorylation of signal transducer and activator of transcription (STAT)-1alpha, and the mRNA and protein expressions of p22phox and Nox1, components of NAD(P)H oxidases, in human mesangial cells (HMCs). Significant increases in O(2)(-) production with IFN-gamma were completely abolished by the flavin-containing enzyme inhibitor, diphenyleneiodonium (10 micromol/l), and the Janus-activated kinase (JAK)2 inhibitor, AG490 (100 micromol/l). Phosphorylated STAT-1alpha was detected after 5 min of IFN-gamma stimulation using Western blot analysis, and binding to the gamma-activating site was observed from 30 min to 4 h, thereafter by electrophoretic mobility shift assay (EMSA). Super-shift analysis in EMSA revealed that the main transcription factor was STAT-1alpha. IFN-gamma significantly increased the expression of p22phox mRNA and protein, although expression was inhibited by AG490. These data suggest that IFN-gamma stimulates O(2)(-) production in HMCs via the JAK-STAT pathway and NAD(P)H oxidase.

An Essential Role of the Jak-2/STAT-3/Cytosolic Phospholipase A2 Axis in Platelet-derived Growth Factor BB-induced Vascular Smooth Muscle Cell Motility

Platelet-derived growth factor-BB (PDGF-BB) is a potent motogen for vascular smooth muscle cells (VSMCs). To understand its motogenic signaling events, we have studied the role of the Janus-activated kinase/signal transducers and activators of transcription (Jak/STAT) pathway and cytosolic phospholipase A(2) (cPLA(2)). PDGF-BB stimulated tyrosine phosphorylation of Jak-2 and STAT-3 in a time-dependent manner in VSMCs. In addition, AG490 and Jak-2KEpRK5, a selective pharmacological inhibitor and a dominant negative mutant, respectively, of Jak-2, attenuated PDGF-BB-induced STAT-3 tyrosine phosphorylation and its DNA binding and reporter gene activities. PDGF-BB induced VSMC motility in a dose-dependent manner with a maximum effect at 10 ng/ml. Dominant negative mutant-dependent suppression of Jak-2 and STAT-3 blocked PDGF-BB-induced VSMC motility. PDGF-BB induced the expression of cPLA(2) in a Jak-2/STAT-3-dependent manner, and pharmacological inhibitors of cPLA(2) prevented PDGFBB-induced VSMC motility. Furthermore, either exogenous addition of arachidonic acid or forced expression of cPLA(2) rescued PDGF-BB-induced VSMC motility from inhibition by blockade of Jak-2 and STAT-3 activation. Together, these results for the first time show that PDGF-BB-induced VSMC motility requires activation of the Jak-2/STAT-3/cPLA(2) signaling axis.

Bradykinin activates the Janus-activated kinase/signal transducers and activators of transcription (JAK/STAT) pathway in vascular endothelial cells: localization of JAK/STAT signalling proteins in plasmalemmal caveolae

Bradykinin (BK) is an important physiological regulator of endothelial cell function. In the present study, we have examined the role of the Janus-activated kinase (JAK)/signal transducers and activators of transcription (STAT) pathway in endothelial signal transduction through the BK B2 receptor (B2R). In cultured bovine aortic endothelial cells (BAECs), BK activates Tyk2 of the JAK family of tyrosine kinases. Activation results in the tyrosine phosphorylation and subsequent nuclear translocation of STAT3. BK also activates the mitogen-activated p44 and p42 protein kinases, resulting in STAT3 serine phosphorylation. Furthermore, Tyk2 and STAT3 form a complex with the B2R in response to BK stimulation. Under basal conditions, Tyk2, STAT3 and the B2R are localized either partially or entirely in endothelial plasmalemmal caveolae. Following BK stimulation of BAECs, however, the B2R and STAT3 are translocated out of caveolae. Taken together, these data suggest that BK activates the JAK/STAT pathway in endothelial cells and that JAK/STAT signalling proteins are localized in endothelial caveolae. Moreover, caveolar localization of the B2R and STAT3 appears to be regulated in an agonist-dependent manner.

Bradykinin activates the Janus-activated kinase/signal transducers and activators of transcription (JAK/STAT) pathway in vascular endothelial cells: localization of JAK/STAT signalling proteins in plasmalemmal caveolae

Bradykinin (BK) is an important physiological regulator of endothelial cell function. In the present study, we have examined the role of the Janus-activated kinase (JAK)/signal transducers and activators of transcription (STAT) pathway in endothelial signal transduction through the BK B2 receptor (B2R). In cultured bovine aortic endothelial cells (BAECs), BK activates Tyk2 of the JAK family of tyrosine kinases. Activation results in the tyrosine phosphorylation and subsequent nuclear translocation of STAT3. BK also activates the mitogen-activated p44 and p42 protein kinases, resulting in STAT3 serine phosphorylation. Furthermore, Tyk2 and STAT3 form a complex with the B2R in response to BK stimulation. Under basal conditions, Tyk2, STAT3 and the B2R are localized either partially or entirely in endothelial plasmalemmal caveolae. Following BK stimulation of BAECs, however, the B2R and STAT3 are translocated out of caveolae. Taken together, these data suggest that BK activates the JAK/STAT pathway in endothelial cells and that JAK/STAT signalling proteins are localized in endothelial caveolae. Moreover, caveolar localization of the B2R and STAT3 appears to be regulated in an agonist-dependent manner.