C6orf120 gene knockout in rats mitigates concanavalin A­induced autoimmune hepatitis via regulating NKT cells.

OBJECTIVE: To elucidate the role of the functional unknown gene C6orf120 in the pathogenesis of AIH and its mechanism of action, using C6orf120 knockout rats. METHODS: An autoimmune hepatitis model was established with 35 mg/kg intravenous injection of concanavalin A (Con A) in C6orf120-knockout (C6orf120-/-) and wild-type (WT) rats. Rats were sacrificed after administering Con A for 0, 12, and 24 h. The peripheral blood, liver, spleen, and mesenteric lymph nodes were collected for follow-up studies. RESULTS: C6orf120 knockout significantly decreased the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and improved the histological damage in Con A-induced autoimmune liver injury.Loss of C6orf120 function significantly increased the frequency of CD3+ CD161+ NKT cells in the peripheral blood, liver, and spleen; downregulated the expression of CD314 (NKG2D) in the liver, spleen, and mesenteric lymph nodes; reduced the expression of inflammatory cytokines and chemokines; and suppressed the mRNA and protein expression of Fas and FasL in the liver. Additionally, C6orf120 knockout significantly downregulated the expression of p-JAK1, p-JAK2, p-STAT1, and p-STAT3 in liver tissue. CONCLUSION: The protective effect of C6orf120 knockout against Con A-induced hepatitis may be due to the inhibition of NKT cell activation, restriction of cytokine and chemokine activities, inhibition of JAK-STAT and Fas/FasL signaling pathway activation, and reduction in liver inflammation and hepatocyte apoptosis.

Cyanidin prevents the hyperproliferative potential of fibroblast-like synoviocytes and disease progression via targeting IL-17A cytokine signalling in rheumatoid arthritis.

The hyperplastic phenotype of fibroblast-like synoviocytes (FLSs) plays an important role for synovitis, chronic inflammation and joint destruction in rheumatoid arthritis (RA). Interleukin 17A (IL-17A), a signature pro-inflammatory cytokine effectively influences the hyperplastic transformation of FLS cells and synovial pannus growth. IL-17A cytokine signalling participates in RA pathology by regulating an array of pro-inflammatory mediators and osteoclastogenesis. Cyanidin, a key flavonoid inhibits IL-17A/IL-17 receptor A (IL-17RA) interaction and alleviates progression and disease severity of psoriasis and asthma. However, the therapeutic efficacy of cyanidin on IL-17A cytokine signalling in RA remains unknown. In the present study, cyanidin inhibited IL-17A induced migratory and proliferative capacity of FLS cells derived from adjuvant-induced arthritis (AA) rats. Cyanidin treatment reduced IL-17A mediated reprogramming of AA-FLS cells to overexpress IL-17RA. In addition, significantly decreased expression of IL-17A dependent cyr61, IL-23, GM-CSF, and TLR3 were observed in AA-FLS cells in response to cyanidin. At the molecular level, cyanidin modulated IL-17/IL-17RA dependent JAK/STAT-3 signalling in AA-FLS cells. Importantly, cyanidin activated PIAS3 protein to suppress STAT-3 specific transcriptional activation in AA-FLS cells. Cyanidin treatment to AA rats attenuated clinical symptoms, synovial pannus growth, immune cell infiltration, and bone erosion. Cyanidin reduced serum level of IL-23 and GM-CSF and expression of Cyr 61 and TLR3 in the synovial tissue of AA rats. Notably, the level of p-STAT-3 protein was significantly decreased in the synovial tissue of AA rats treated with cyanidin. This study provides the first evidence that cyanidin can be used as IL-17/17RA signalling targeting therapeutic drug for the treatment of RA and this need to be investigated in RA patients.

Enhancer of polycomb coordinates multiple signaling pathways to promote both cyst and germline stem cell differentiation in the Drosophila adult testis.

Stem cells reside in a particular microenvironment known as a niche. The interaction between extrinsic cues originating from the niche and intrinsic factors in stem cells determines their identity and activity. Maintenance of stem cell identity and stem cell self-renewal are known to be controlled by chromatin factors. Herein, we use the Drosophila adult testis which has two adult stem cell lineages, the germline stem cell (GSC) lineage and the cyst stem cell (CySC) lineage, to study how chromatin factors regulate stem cell differentiation. We find that the chromatin factor Enhancer of Polycomb [E(Pc)] acts in the CySC lineage to negatively control transcription of genes associated with multiple signaling pathways, including JAK-STAT and EGF, to promote cellular differentiation in the CySC lineage. E(Pc) also has a non-cell-autonomous role in regulating GSC lineage differentiation. When E(Pc) is specifically inactivated in the CySC lineage, defects occur in both germ cell differentiation and maintenance of germline identity. Furthermore, compromising Tip60 histone acetyltransferase activity in the CySC lineage recapitulates loss-of-function phenotypes of E(Pc), suggesting that Tip60 and E(Pc) act together, consistent with published biochemical data. In summary, our results demonstrate that E(Pc) plays a central role in coordinating differentiation between the two adult stem cell lineages in Drosophila testes.

Effects of 9-cis-retinoic acid on the proliferation and apoptosis of cutaneous T-cell lymphoma cells.

The vitamin A derivative 9-cis-retinoic acid (9-cis-RA) has been used for the treatment and prevention of cutaneous T-cell lymphoma (CTCL). However, the precise mechanism by which 9-cis-RA treatment ameliorates CTCL remains elusive. Our research shows that 9-cis-RA inhibits proliferation and induces apoptosis in CTCL cells in a dose-dependent and time-dependent manner. 9-Cis-RA also induced G0/G1 cell cycle arrest by downregulation of cyclin D1. We confirmed that 9-cis-RA significantly decreased phosphorylation of JAK1, STAT3, and STAT5 and downregulated Bcl-xL and cyclin D1, indicating that 9-cis-RA inhibited the activation of JAK/STAT signaling. Meanwhile, 9-cis-RA also activated classical RA-mediated transcription by retinoic acid receptors (RAR) and/or retinoid X receptors (RXR) in a CTCL cell line. Thus, 9-cis-RA may be effective for chemotherapy and may prevent human CTCL by inhibiting proliferation and inducing apoptosis by inhibition of the JAK/STAT pathway and activation of the RAR/RXR pathway.

Remote Control of Intestinal Stem Cell Activity by Haemocytes in Drosophila.

The JAK/STAT pathway is a key signaling pathway in the regulation of development and immunity in metazoans. In contrast to the multiple combinatorial JAK/STAT pathways in mammals, only one canonical JAK/STAT pathway exists in Drosophila. It is activated by three secreted proteins of the Unpaired family (Upd): Upd1, Upd2 and Upd3. Although many studies have established a link between JAK/STAT activation and tissue damage, the mode of activation and the precise function of this pathway in the Drosophila systemic immune response remain unclear. In this study, we used mutations in upd2 and upd3 to investigate the role of the JAK/STAT pathway in the systemic immune response. Our study shows that haemocytes express the three upd genes and that injury markedly induces the expression of upd3 by the JNK pathway in haemocytes, which in turn activates the JAK/STAT pathway in the fat body and the gut. Surprisingly, release of Upd3 from haemocytes upon injury can remotely stimulate stem cell proliferation and the expression of Drosomycin-like genes in the intestine. Our results also suggest that a certain level of intestinal epithelium renewal is required for optimal survival to septic injury. While haemocyte-derived Upd promotes intestinal stem cell activation and survival upon septic injury, haemocytes are dispensable for epithelium renewal upon oral bacterial infection. Our study also indicates that intestinal epithelium renewal is sensitive to insults from both the lumen and the haemocoel. It also reveals that release of Upds by haemocytes coordinates the wound-healing program in multiple tissues, including the gut, an organ whose integrity is critical to fly survival.

Coordinate regulation of stem cell competition by Slit-Robo and JAK-STAT signaling in the Drosophila testis.

Stem cells in tissues reside in and receive signals from local microenvironments called niches. Understanding how multiple signals within niches integrate to control stem cell function is challenging. The Drosophila testis stem cell niche consists of somatic hub cells that maintain both germline stem cells and somatic cyst stem cells (CySCs). Here, we show a role for the axon guidance pathway Slit-Roundabout (Robo) in the testis niche. The ligand Slit is expressed specifically in hub cells while its receptor, Roundabout 2 (Robo2), is required in CySCs in order for them to compete for occupancy in the niche. CySCs also require the Slit-Robo effector Abelson tyrosine kinase (Abl) to prevent over-adhesion of CySCs to the niche, and CySCs mutant for Abl outcompete wild type CySCs for niche occupancy. Both Robo2 and Abl phenotypes can be rescued through modulation of adherens junction components, suggesting that the two work together to balance CySC adhesion levels. Interestingly, expression of Robo2 requires JAK-STAT signaling, an important maintenance pathway for both germline and cyst stem cells in the testis. Our work indicates that Slit-Robo signaling affects stem cell function downstream of the JAK-STAT pathway by controlling the ability of stem cells to compete for occupancy in their niche.

Honokiol inhibits sphere formation and xenograft growth of oral cancer side population cells accompanied with JAK/STAT signaling pathway suppression and apoptosis induction.

BACKGROUND: Eliminating cancer stem cells (CSCs) has been suggested for prevention of tumor recurrence and metastasis. Honokiol, an active compound of Magnolia officinalis, had been proposed to be a potential candidate drug for cancer treatment. We explored its effects on the elimination of oral CSCs both in vitro and in vivo. METHODS: By using the Hoechst side population (SP) technique, CSCs-like SP cells were isolated from human oral squamous cell carcinoma (OSCC) cell lines, SAS and OECM-1. Effects of honokiol on the apoptosis and signaling pathways of SP-derived spheres were examined by Annexin V/Propidium iodide staining and Western blotting, respectively. The in vivo effectiveness was examined by xenograft mouse model and immunohistochemical tissue staining. RESULTS: The SP cells possessed higher stemness marker expression (ABCG2, Ep-CAM, Oct-4 and Nestin), clonogenicity, sphere formation capacity as well as tumorigenicity when compared to the parental cells. Treatment of these SP-derived spheres with honokiol resulted in apoptosis induction via Bax/Bcl-2 and caspase-3-dependent pathway. This apoptosis induction was associated with marked suppression of JAK2/STAT3, Akt and Erk signaling pathways in honokiol-treated SAS spheres. Consistent with its effect on JAK2/STAT3 suppression, honokiol also markedly inhibited IL-6-mediated migration of SAS cells. Accordingly, honokiol dose-dependently inhibited the growth of SAS SP xenograft and markedly reduced the immunohistochemical staining of PCNA and endothelial marker CD31 in the xenograft tumor. CONCLUSIONS: Honokiol suppressed the sphere formation and xenograft growth of oral CSC-like cells in association with apoptosis induction and inhibition of survival/proliferation signaling pathways as well as angiogenesis. These results suggest its potential as an integrative medicine for combating oral cancer through targeting on CSCs.

Eriobotrya japonica Water Extract Characterization: An Inducer of Interferon-Gamma Production Mainly by the JAK-STAT Pathway.

Eriobotrya japonica (Thunb.) Lindl. (Loquat) (EJ) has been used as a medicinal plant to treat chronic bronchitis, coughs, phlegm, high fever and gastro-enteric disorders. Since the traditional use of EJ is related to modulating inflammation processes, our earlier studies on EJ leaves were performed on the water extract to investigate specific cytokines' modulation. These earlier studies, however, have shown that EJ leaf water extract (WE) and the water phase (WP) induce cytokines' production in in vitro and in vivo models. Therefore, the aim of this study was to specify the group(s) of compounds in EJ leaves that have this immunomodulatory activity and their mechanism of action. WE was obtained from boiling the leaves followed by butanol extraction, yielding a butanol-water phase (WP). WP was then subjected to methanol:acetone fractionation, yielding upper (MAU) and lower (MAL) phases. For further fractionation, MAU was subjected to column chromatography followed by elution with ethanol:water (EW), methanol:ethanol (ME) and, lastly, acetone:water (AW), respectively, to reveal three sub-fractions; MAU-EW, MAU-ME and MAU-AW. MAU-AW significantly increased IFN-γ production from unstimulated and stimulated mouse spleen cells, as well as CD3+ T cells and natural killer cells. Furthermore, the fold increase of IFN-γ production by MAU-AW was concentration dependent, higher than the parent extract or any of the other sub-fractions, and such an IFN-γ increase was reversed by two JAK-STAT inhibitors. In addition, MALDI-TOF-MS analysis of the extracts and sub-fractions showed compounds with molecular weights of >500 Daltons. The MAU-AW sub-fraction contained more polar compounds, such as flavonol and caffeic glycosides. In conclusion, these polar compounds in the EJ extract are responsible for inducing IFN-γ production. Further chemical elucidation is warranted to lead to a specific IFN-γ inducer and an immunomodulator in polarizing immune cells and balancing immune responses in certain diseases.

Rabaptin-5 and Rabex-5 are neoplastic tumour suppressor genes that interact to modulate Rab5 dynamics in Drosophila melanogaster.

Endocytosis plays an important role in the regulation of tumour growth and metastasis. In Drosophila, a number of endocytic neoplastic tumour suppressor genes have been identified that when mutated cause epithelial disruption and over-proliferation. Here we characterise the Drosophila homologue of the Rab5 effector Rabaptin-5, and show that it is a novel neoplastic tumour suppressor. Its ability to bind Rab5 and modulate early endosomal dynamics is conserved in Drosophila, as is its interaction with the Rab5 GEF Rabex5, for which we also demonstrate neoplastic tumour suppressor characteristics. Surprisingly, we do not observe disruption of apico-basal polarity in Rabaptin-5 and Rabex-5 mutant tissues; instead the tumour phenotype is associated with upregulation of Jun N-terminal Kinase (JNK) and Janus Kinase (JAK)/Signal Transducer and Activator of Transcription (STAT) signalling.

miR-30 overexpression promotes glioma stem cells by regulating Jak/STAT3 signaling pathway.

Malignant glioma is the most common intracranial tumor with poor prognosis. It is well believed that glioma stem cells (GSCs) are responsible for the initiation and progression of glioma. Janus kinase/signal transducer and activator of transcription (Jak/STAT3) pathway plays a key role in the functions of GSCs. However, the regulatory mechanism of Jak/STAT3 pathway has not been completely elucidated. This study employed multidisciplinary approaches to investigate the upstream regulators of Jak/STAT3 signaling in GSCs. miR-30 was found to be overexpressed in the GSCs derived from U-87 MG and primary glioma cells, compared with non-stem-cell-like glioma cells and normal cells. Downregulation of miR-30 was able to suppress Jak/STAT3 pathway and reduce the tumorigenecity of GSCs. miR-30 decreased the expression of suppressor of cytokine signaling 3 (SOCS3) expression by targeting 3'UTR of its mRNA. The silencing of SOCS3 abolished the effect of miR-30 downregulation on GSCs. Collectively, there is a regulatory pathway consisting of miR-30, SOCS3, and Jak/STAT3 in GSCs, and targeting this pathway may be a promising strategy to treat glioma.

Over-Expression of Cyclin D1 Promotes NSCs Proliferation and Induces the Differentiation into Astrocytes Via Jak-STAT3 Pathways.

Precise control of the proliferation and differentiation of multipotent neural stem cells (NSCs) is crucial for the proper development of the nervous system. Although cyclinD1 has been implicated as a cause of cancer in many studies, its roles in NSCs remain elusive. In this study, we examined the over-expression of cyclinD1 in controlling the self-renewal and differentiation of NSCs. Moreover, we found that the over-expression of cyclinD1 can drive cells to enter S phase and support the clonal self-renewing growth of NSCs. During the differentiation of NSCs, the over-expression of cyclinD1 promoted the generation of astrocytes, and their promotion likely occurred through synergistic phosphorylation of the signal transducer and activator of transcription 3. Our data suggest that the over-expression of cyclinD1 promotes the proliferation of NSCs and induces their differentiation into astrocytes via Jak-STAT3 pathways.

Effect of Rhizoma paridis total saponins on apoptosis of colorectal cancer cells and imbalance of the JAK/STAT3 molecular pathway induced by IL-6 suppression.

We observed the influence of different concentrations of Rhizoma paridis total saponins (RPTS) on the apoptosis of colorectal cancer cells and explored the internal mechanism involved. We determined whether RPTS influences the interleukin-6 (IL-6)/Janus kinase (JAK)-signal transducer and activator of transcription-3 (STAT3) apoptosis molecular pathway and looked for colon cancer-related signal transduction pathways or targets inducing apoptosis. We also cultured SW480 colorectal cancer cells using different concentrations of RPTS (10, 20, 40, and 80 µg/ mL), and observed the effect of RPTS on SW480 cell morphology under a fluorescence inverted microscope. We detected serum IL-6 using the polymerase chain reaction and the expression of JAK-STAT3 protein by western blot. After treating SW480 with RPTS and Hoechst 33258 dyeing, we found that the typical apoptosis morphology had changed. Secretion of IL-6 in the serum decreased significantly (P < 0.05), and STAT3 levels were reduced. RPTS can significantly promote apoptosis in SW480 colorectal cancer cells. The mechanism may be that it suppresses the secretion of IL-6 and inhibits the IL-6/JAK-STAT3 protein signaling pathway.

Early functional and transcriptomic changes in the myocardium predict outcome in a long-term rat model of sepsis.

Myocardial function is depressed in sepsis and is an important prognosticator in the human condition. Using echocardiography in a long-term fluid-resuscitated Wistar rat model of faecal peritonitis we investigated whether depressed myocardial function could be detected at an early stage of sepsis and, if so, whether the degree of depression could predict eventual outcome. At 6 h post-insult, a stroke volume <0.17 ml prognosticated 3-day mortality with positive and negative predictive values of 93 and 80%, respectively. Subsequent fluid loading studies demonstrated intrinsic myocardial depression with poor-prognosis animals tolerating less fluid than either good-prognosis or sham-operated animals. Cardiac gene expression analysis at 6 h detected 527 transcripts significantly up- or down-regulated by the septic process, including genes related to inflammatory and cell cycle pathways. Predicted mortality was associated with significant differences in transcripts of genes expressing proteins related to the TLR2/MyD88 (Toll-like receptor 2/myeloid differentiation factor 88) and JAK/STAT (Janus kinase/signal transducer and activator of transcription) inflammatory pathways, ß-adrenergic signalling and intracellular calcium cycling. Our findings highlight the presence of myocardial depression in early sepsis and its prognostic significance. Transcriptomic analysis in heart tissue identified changes in signalling pathways that correlated with clinical dysfunction. These pathways merit further study to both better understand and potentially modify the disease process.

ß-Escin sodium inhibits inducible nitric oxide synthase expression via downregulation of the JAK/STAT pathway in A549 cells.

ß-escin, a triterpene saponin, is one of the major active compounds extracted from horse chestnut (Aesculus hippocastanum) seed. Previous work has found that ß-escin sodium has antiinflammatory and antitumor effects. In the present study, we investigated its effect on cell proliferation and inducible nitric-oxide synthase (iNOS) expression in human lung carcinoma A549 cells. ß-escin sodium (5-40 µg/mL) inhibited cytokine mixture (CM)-induced nitric oxide (NO) production in A549 cells by reducing the expression of iNOS. ß-escin sodium suppressed phosphorylation and nuclear translocation of STAT1 (Tyr701) and STAT3 (Tyr705) induced by CM but did not affect the activation of c-Jun and NF-κB. ß-escin sodium inhibited the activation of protein tyrosine kinase JAK2. Pervanadate treatment reversed the ß-escin sodium-induced downregulation of STAT3 and STAT1. ß-escin sodium treatment enhanced an activating phosphorylation of the phosphatase SHP2. Small interfering RNA-mediated knockdown of SHP2 inhibited ß-escin sodium-induced phospho-STAT dephosphorylation. Moreover ß-escin sodium reduced the activation of p38 MAPK. Finally, ß-escin sodium inhibited the proliferation of A549 cells, did not change the cell membrane's permeability, nuclear morphology and size and the mitochondria's transmembrane potential of A549 cells. Taken together, these results demonstrate that ß-escin sodium could downregulate iNOS expression through inhibiting JAK/STAT signaling and p38 MAPK activation in A549 cells. ß-escin sodium has a marked antiproliferative effect on A549 cells at least in part by inhibiting the JAK/STAT signaling pathway, but not by a cytotoxic effect. ß-escin sodium would be useful as a chemopreventive agent or a therapeutic against inflammatory-associated tumor. © 2011 Wiley Periodicals, Inc.

Inflammatory cytokines regulate microRNA-155 expression in human retinal pigment epithelial cells by activating JAK/STAT pathway.

Inflammatory response of the retinal pigment epithelium plays a critical role in the pathogenesis of retinal degenerative diseases such as age-related macular degeneration. Our previous studies have shown that human retinal pigment epithelial (HRPE) cells, established from adult donor eyes, respond to inflammatory cytokines by enhancing the expression of a number of cytokines and chemokines. To investigate the role of microRNA (miRNA) in regulating this response, we performed microarray analysis of miRNA expression in HRPE cells exposed to inflammatory cytokine mix (IFN-γ+TNF-α+IL-1ß). Microarray analysis revealed ∼11-fold increase in miR-155 expression, which was validated by real-time PCR analysis. The miR-155 expression was enhanced when the cells were treated individually with IFN-γ, TNF-α or IL-1ß, but combinations of the cytokines exaggerated the effect. The increase in miR-155 expression by the inflammatory cytokines was associated with an increase in STAT1 activation as well as an increase in protein binding to putative STAT1 binding elements present in the MIR155 gene promoter region. All these activities were effectively blocked by JAK inhibitor 1. Our results show that the inflammatory cytokines increase miR-155 expression in human retinal pigment epithelial cells by activating the JAK/STAT signaling pathway.

Simvastatin prevents cardiac hypertrophy in vitro and in vivo via JAK/STAT pathway.

Simvastatin (SIM), a HMG-CoA reductase inhibitor, has therapeutic effects that are not limited to cholesterol reduction. In this study, we investigated the change in the cell surface area and protein content of cultured rat cardiomyocytes on exposure to cardiotrophin-1 (CT-1), a cytokine involved in the growth and survival of cardiac cells, plus SIM, and thus confirmed that SIM ameliorated cardiomyocyte hypertrophy induced by CT-1. We also showed that SIM attenuated cardiac hypertrophy in rats with pressure overload due to abdominal aortic constriction by measuring such parameters as systolic blood pressure, ratio of heart weight to body weight and ratio of left ventricular weight to body weight in rats as well as cross-sectional area of cardiomyocytes. Western blot analysis indicated that the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway was involved in the mechanisms underlying the in vitro and in vivo inhibitory effects of SIM on cardiac hypertrophy. Moreover, the effect of SIM amelioration on CT-1-induced cultured cardiomyocyte hypertrophy might be related to the change in angiotensinogen (AGT) mRNA expression, as evidenced by RT-PCR analysis, and the subsequent alteration in angiotensin II (Ang II) levels. The results of our study provide further evidence that SIM, like other HMG-CoA reductase inhibitors, is a promising drug for prevention and treatment of cardiac hypertrophy.

STAT3 Expression and Activity are Up-Regulated in Diffuse Large B Cell Lymphoma of Dogs.

BACKGROUND: The Janus Kinase (JAK) and Signal Transducer and Activator of Transcription (STAT) pathways play important roles in the pathogenesis of diffuse large B cell lymphoma (DLBCL) in humans, and up-regulated STAT3 expression and activity are associated with worse clinical outcome in humans. No studies have evaluated the JAK-STAT signaling pathway in DLBCL of dogs. HYPOTHESIS: STAT3 pathway is deregulated in DLBCL in dogs. We aim to assess the expression, activation, and cellular localization of STAT3 and mitogen-activated protein kinase ERK1/2 in DLBCL of dogs. ANIMALS: Forty-three client-owned dogs diagnosed with DLBCL by histopathology METHODS: Retrospective analysis of DLBCL in dogs, including patient characteristics and treatment, immunohistochemistry, and protein expressions by Western blot. RESULTS: A higher percentage of STAT3 and p-STAT3 immunolabelled cells were observed in DLBCL of dogs when compared to normal canine lymph nodes. In STAT3 immunolabelled cells, STAT3 has higher nuclear expression in lymphoma samples than in normal or reactive lymph nodes. In addition to up-regulated STAT3 expression and activation, mitogen-activated kinase ERK1/2 activation is up-regulated in DLBCL of dogs. CONCLUSION AND CLINICAL IMPORTANCE: Compared with the normal canine lymph node, DLBCL of dogs has up-regulated STAT3 pathway. Our results support future investigation of JAK inhibitors in the treatment of DLBCL in dogs.

Changes in the Expression Profile of JAK/STAT Signaling Pathway Genes and Mirnas Regulating their Expression Under the Adalimumab Therapy.

OBJECTIVE: The aim of this study was to evaluate the influence of adalimumab on the expression pattern of genes associated with JAK/STAT signaling pathway in Normal Human Dermal Fibroblast (NHDF) cells stimulated with 8 µg/ml of adalimumab and the identification of miRNAs regulating these genes' expression. METHOD: NHDFs were cultured with or without the presence of adalimumab for 2, 8, and 24h. The microarray technology was used to determine expression profile of mRNAs and miRNAs. RESULTS: Out of 22283 ID mRNA, 37 are associated with the JAK/STAT signaling pathway. It can be observed that 18 mRNAs differentiate NHDFs cultures with adalimumab from control. The analysis of miRNAs showed that, among 1105 ID miRNAs, 20 miRNAs are differentiating in cells treated with adalimumab for 2h, 9 miRNAs after 8h, and only 3 miRNAs after 24h. CONCLUSION: It can be observed that miRNAs play an extremely important role in the regulation of the expression of genes associated with JAK/STAT signaling pathway. The results of this study show the possibility of using changes in mRNAs and miRNAs profile expression, as complementary molecular markers of adalimumab treatment effectiveness.

Constitutive and induced activation of JAK/Stat pathway in leukemogenic and asymptomatic human T-cell lymphoptropic virus type 1 (HTLV-1) transformed rabbit cell lines.

We have shown that Vav and C-cbl are activated in the leukemogenic HTLV-I transformed rabbit T cell line RH/K34 but not in the asymptomatic one RH/K30. We extended these observations and investigated the activation of JAKs (Janus Kinase) and the STATs (signal transducers and activators of transcription) pathway in these cell lines. We found that Tyk2 and Stat3 are constitutively tyrosine phosphorylated in the leukemogenic cell line. Phosphorylation of Tyk2 can be induced in RH/K30 by treatment with IL-10, interferon alpha (INFalpha) and by the supernatant of RH/K34 which contain both these cytokines. Stat3 tyrosine phosphorylation can be induced in RH/K30 by treatment with IL-10. Transfection of RL-5, a rabbit T-cell line, with the RH/K34 viral clone transiently increased the expression of serine/threonine phosphorylated Stat3. Differences were also observed on induced Stat5 phosphorylation. These results highlight the relation between the virulence of HTLV-I and the activation of the Jak/Stat pathway.

Interleukin-17 upregulates vascular endothelial growth factor by activating the JAK/STAT pathway in nucleus pulposus cells.

OBJECTIVES: Intervertebral disc (IVD) related diseases and age-related IVD degeneration are responsible for significant morbidity. Inflammatory mediators and pro-inflammatory cytokines, including interleukin (IL)-17, show elevated expression in degenerated disc tissue. IL-17 is reported to transduce signals across the cell membrane predominantly via the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signal transduction pathway, leading to transcriptional activation of target genes. METHODS: In this study, we investigated whether the JAK/STAT pathway plays a role in IL-17-mediated signaling in the nucleus pulposus (NP) cells of IVDs. Vascular endothelial growth factor (VEGF) and IL-17 were found to be highly expressed in human degenerated NP tissue. In isolated rat NP cells, IL-17-induced VEGF expression in a time- and dose-dependent manner. Rat NP cells were co-transfected with VEGF promoter plasmid along with constitutively active STAT1, STAT3 or JAK2 plasmid. VEGF promoter activity was found to be increased by STAT1, STAT3 and JAK2 in IL-17-treated cells. Transfection of cultured rat NP cells with STAT1 or STAT3 lentiviral short hairpin RNAs or treatment with the JAK2 inhibitor AG490 significantly reduced IL-17-stimulated VEGF expression. CONCLUSIONS: IL-17 upregulated VEGF expression in rat NP cells mediated by the JAK/STAT pathway, and elevated levels of IL-17 and VEGF are present in human degenerated NP tissue. These findings provide new insight into the pathology of IVD degeneration.