OBJECTIVETo study the inhibitive effect of exogenous carbon monoxide-releasing molecules 2 (CORM-2) on the activation of Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway in sepsis.

METHODSRAW264.7 cells were divided into normal control group, LPS group (10 mg/mL LPS, the same concentration below), LPS + inactive CORM-2 (iCORM-2) group, LPS + 50 mmol/L CORM-2 group, and LPS + 100 mmol/L CORM-2 group. TNF-alpha level in the supernatant was determined with ELISA, and the phosphorylation levels of JAK1 and JAK3 were determined with Western blot. Thirty-five male BALB/c mice were divided into normal control group, cecal ligation and puncture (CLP) group, CLP + iCORM-2 (8.0 mg/kg) group and CLP + CORM-2 group (8.0 mg/kg) according to the random number table. Mice in CLP + CORM-2 group were treated the same as mice in CLP group except for administration of CORM-2 after CLP. The plasma levels of TNF-alpha, IL-1beta, and the phosphorylation levels of JAK1, JAK3 in liver tissue were determined with ELISA 24 hours post CLP. Data were processed with t test.

RESULTSCompared with that of normal control group [(1.9 +/- 0.3) pg/mL], the TNF-alpha level [(8.2 +/- 2.7) pg/mL, t = 2.844, P < 0.01] and phosphorylation levels of JAK1, JAK3 in LPS group increased significantly; while TNF-alpha levels in LPS + 50 mmol/L CORM-2 and LPS + 100 mmol/L CORM-2 groups decreased obviously as compared with that of LPS group [(5.7 +/- 1.4), (3.2 +/- 0.9) pg/mL, with t value respectively 2.104 and 2.363, P values all below 0.05], and it was the same with phosphorylation levels of JAK1, JAK3 in a dose-dependent manner. Compared with those of normal control group, plasma levels of TNF-alpha and IL-1beta and phosphorylation levels of JAK1, JAK3 in liver tissue significantly increased in CLP group (with t value respectively 2.916 and 2.796, and P values all below 0.05); while plasma levels of TNF-alpha and IL-1beta and the phosphorylation levels of JAK1, JAK3 in liver tissue decreased significantly in CLP + CORM-2 group (with t value respectively 2.115 and 2.398, and P values all below 0.05).

CONCLUSIONSExogenous CORM-2 can obviously inhibit the phosphorylation of JAKs molecules and then inhibit the activation of JAK/STAT signal pathway in sepsis, and decrease the expression of downstream cytokines to effectively prevent cascade reaction in the inflammatory response after severe infection.

Animals ; Carbon Monoxide ; pharmacology ; Cells, Cultured ; Interleukin-1beta ; blood ; Janus Kinase 1 ; metabolism ; Janus Kinase 3 ; metabolism ; Male ; Mice ; Mice, Inbred BALB C ; Organometallic Compounds ; pharmacology ; Phosphorylation ; Sepsis ; metabolism ; Signal Transduction ; Tumor Necrosis Factor-alpha ; blood

OBJECTIVETo explore the molecular mechanisms of arsenic trioxide (As2O3) inhibiting NB4 cells proliferation.

METHODSThe Janus kinase 1 (JAK1) protein level and its phosphorylation level in NB4 cells was detected by Western blots. NB4 cells were transfected with JAK1 siRNA or JAK1 plasmid to make JAK1 gene silenced or overexpressed. The inhibition of NB4 cells proliferation was measured by MTT assay and Trypan blue exclusion respectively. The variation of phosphorylation level of JAK1 and the cell cycle inhibitor P21 were determined by Western blots.

RESULTSJAK1 protein was expressed stably in NB4 cells, with no phosphorylation. The phosphorylation of JAK1 was enhanced after the NB4 cells treated with As2O3. After NB4 cells transfected with JAK1 siRNA, the expression level of JAK1 was obviously lower than that of in the non-specific siRNA group and blank control group. The effect of As2O3 inhibiting NB4 cells proliferation was weaker in the JAK1 siRNA transfected group. The inhibiting rate of 4 micromol/L As2O3 on NB4 cells proliferation of JAK1 siRNA group was 49.12% being lower than that of the non-specific siRNA group (74.58%) and control group (72.33%). After NB4 cells transfected with JAK1 plasmid, the JAK1 expression level in wild-type and mutant type plasmid groups were significantly higher than those in the empty plasmid group, moreover the effect of As2O3 inhibiting proliferation was stronger in wild-type plasmid group. The inhibiting rate of 4 micromol/L As2O3 on NB4 cells proliferation of wild-type plasmid group was 69.53% being higher than that of the mutant type JAK1 plasmid group (37.26%) and the empty plasmid group (39.61%). The expression level of P21 was up-regulated after the NB4 cells treated with As2O3.

CONCLUSIONJAK1 is expressed stably in NB4 cells, but has no activity. Arsenic trioxide inhibits the proliferation of NB4 cells through activating the JAK1. P21 is up-regulated after arsenic trioxide activated the JAK1 to inhibit the proliferation of NB4 cells.

Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Cell Proliferation ; drug effects ; Humans ; Janus Kinase 1 ; genetics ; metabolism ; Oxides ; pharmacology ; Signal Transduction ; drug effects ; Tumor Cells, Cultured

Animals ; Asthma ; drug therapy ; metabolism ; Genistein ; pharmacology ; therapeutic use ; Guinea Pigs ; Interleukin-4 ; genetics ; metabolism ; Janus Kinase 1 ; genetics ; metabolism ; Lung ; metabolism ; Male ; Protein Kinase Inhibitors ; pharmacology ; therapeutic use

This study was aimed to determine the in vivo signal transduction pathway responsible for isoproterenol (ISO)-induced cardiac hypertrophy or remodeling. Mice were treated with ISO (15 mg/kg body weight) or vehicle by intraperitoneal injection (i.p.). Activation of mitogen-activted protein kinase (MAPK), NF-kappaB and JAK/STAT pathway in the left ventricular myocardium was measured by Western blot analysis. ISO significantly activated MAPK (ERK1/2 and p38) at early phase (5 min); biphasic activation of NF-kappaB was observed in our in vivo study; and ISO caused a delayed STAT3 activation (at 60 to 240 min) in mouse myocardium. Taken together, these results indicate that ISO activates these signal transduction pathways in different time course.
Animals ; Heart ; drug effects ; Isoproterenol ; pharmacology ; Janus Kinase 1 ; metabolism ; Male ; Mice ; Mice, Inbred BALB C ; Mitogen-Activated Protein Kinases ; metabolism ; Myocardium ; metabolism ; NF-kappa B ; metabolism ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; Time Factors

OBJECTIVETo explore the changes in the gene expression profiles in HepG2 cells transfected by human hepatocyte growth factor (hHGF) and analyze the signal transduction pathway in liver fibrosis regulated by hHGF.

METHODA 20,000 gene cDNA microarray (Affymetrix) was used to examine the gene expressions in the HepG2 cells transfected by hHGF. The differentially expressed genes were identified and some genes with possible contribution to hepatic fibrosis were subjected to real-time PCR analysis.

RESULTThe differentially expressed genes were mostly transcription regulatory molecules, cytokines, signal transduction, glucose metabolism, lipid metabolism. The results of real-time PCR showed up-regulated STAT1 and MAPK1 expression in the cells as were consistent with genechip analysis results.

CONCLUSIONhHGF gene transfection results in the gene expression profile changes in HepG2 cells. HGF may regulate liver fibrosis via the JAK/STAT and MAPK pathways.

Gene Expression Profiling ; Gene Expression Regulation ; Hep G2 Cells ; Hepatocyte Growth Factor ; genetics ; metabolism ; Humans ; Janus Kinases ; metabolism ; Liver Cirrhosis ; genetics ; metabolism ; Mitogen-Activated Protein Kinase 1 ; metabolism ; STAT1 Transcription Factor ; metabolism ; Signal Transduction ; physiology ; Transfection

Specific gene expressions of host cells by spontaneous STAT6 phosphorylation are major strategy for the survival of intracellular Toxoplasma gondii against parasiticidal events through STAT1 phosphorylation by infection provoked IFN-γ. We determined the effects of small molecules of tyrosine kinase inhibitors (TKIs) on the growth of T. gondii and on the relationship with STAT1 and STAT6 phosphorylation in ARPE-19 cells. We counted the number of T. gondii RH tachyzoites per parasitophorous vacuolar membrane (PVM) after treatment with TKIs at 12-hr intervals for 72 hr. The change of STAT6 phosphorylation was assessed via western blot and immunofluorescence assay. Among the tested TKIs, Afatinib (pan ErbB/EGFR inhibitor, 5 µM) inhibited 98.0% of the growth of T. gondii, which was comparable to pyrimethamine (5 µM) at 96.9% and followed by Erlotinib (ErbB1/EGFR inhibitor, 20 µM) at 33.8% and Sunitinib (PDGFR or c-Kit inhibitor, 10 µM) at 21.3%. In the early stage of the infection (2, 4, and 8 hr after T. gondii challenge), Afatinib inhibited the phosphorylation of STAT6 in western blot and immunofluorescence assay. Both JAK1 and JAK3, the upper hierarchical kinases of cytokine signaling, were strongly phosphorylated at 2 hr and then disappeared entirely after 4 hr. Some TKIs, especially the EGFR inhibitors, might play an important role in the inhibition of intracellular replication of T. gondii through the inhibition of the direct phosphorylation of STAT6 by T. gondii.
Antiparasitic Agents/pharmacology ; Blotting, Western ; Cell Line ; Enzyme Activation/drug effects ; Fluorescent Antibody Technique ; Humans ; Janus Kinase 1/metabolism ; Janus Kinase 3/metabolism ; Phosphorylation/drug effects ; Quinazolines/*pharmacology ; STAT6 Transcription Factor/*metabolism ; Signal Transduction/*drug effects ; Toxoplasma/*drug effects/physiology ; Toxoplasmosis/physiopathology

Mouse embryonic stem cells (ES cells) are pluripotent in that they can give rise to almost all the cell types in vitro and in vivo. Also, they can sustain self-renewal in vitro owing to symmetrical mitosis, i.e., only the cell number increases while the daughter cells remain pluripotent. Self-renewal and pluripotency of ES cells are under stringent regulation of several signaling pathways. Activation of either JAK-STAT3 or PI3K, the downstream cascade of gp130, can maintain the self-renewal of ES cells, while phosphorylation of another gp130-related branch, SHP2-Ras-ERK, drives the differentiation. BMP2/4-mediated signaling is capable of suppressing the differentiation of ES cells in collaboration with activated JAK-STAT3 under serum free culture conditions. Other signaling such as Wnt also contributes to the self-renewal of ES cells. Generally, the network, which is composed of various signaling pathways, modulates the self-renewal and differentiation of mouse ES cells precisely. This review focuses on the role of gp130 in proliferation of mouse ES cells including inhibitory effect of JAK-STAT3 pathway activation on differentiation of mouse ES cells, maintenance effect of PI3K pathway activation on self-renewal of ES cells, promotive effect of SHP-2-Ras-ERK pathway activation on differentiation of ES cells, and influence of other signaling pathways on self-renewal of mouse ES cells, including maintenance effect of BMP combination with LIF under serum free culture conditions on self-renewal of ES cells and promotive effect of Wnt pathway activation on self-renewal of ES cells.
Animals ; Cell Differentiation ; physiology ; Cell Proliferation ; Cell Survival ; Cells, Cultured ; Cytokine Receptor gp130 ; metabolism ; Embryonic Stem Cells ; cytology ; physiology ; Janus Kinase 1 ; metabolism ; Leukemia Inhibitory Factor ; metabolism ; Mice ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; physiology

The aim of this study was to investigate the relationship between the effects of different doses of X-rays on DNA damage and JAK/STAT signaling pathway activation in A549 cells. The A549 cells were radiated with X-rays at doses of 2, 4, and 8 Gy. The proliferation of A549 cells was detected by CCK8 method. The content of interleukin 6 (IL-6) in culture medium at different time points after irradiation was detected by enzyme-linked immunoassay, and the expression levels of IL-6 receptor (IL-6R) and p53 binding protein 1 (53BP1) were detected by immunofluorescent staining. The expression levels of JAK2, p-JAK2, STAT3 and p-STAT3 were detected by Western blot. The results showed that, compared with the control group, X-ray irradiation reduced the cellular proliferation, up-regulated the expression of 53BP1, increased the IL-6 content in the medium supernatant, and up-regulated the protein expression levels of IL-6R, JAK2, p-JAK2, STAT3, and p-STAT3. The above effects of X-ray irradiation were dose-dependent. These results suggest that the mechanism by which X-rays cause DNA damage in A549 cells may involve activation of the JAK/STAT signaling pathway.
A549 Cells ; DNA Damage ; radiation effects ; Humans ; Janus Kinase 2 ; metabolism ; Receptors, Interleukin-6 ; metabolism ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; Tumor Suppressor p53-Binding Protein 1 ; metabolism ; X-Rays

The aim of this study was to explore the molecule mechanism of resveratrol antileukaemia. The mouse lymphocytic leukemia L1210 cells were cultured and the expressions of pJAK1 and pSTAT3 protein in L1210 cells were detected by immunohistochemistry and immunoprecipitation in vitro. The mouse model with L1210 leukemia ascites carcinoma was established and activities of singal transduction pathway molecules pJAK1 and pSTAT3 were measured by Western blot and immunohistochemistry assay in vitro. The results indicated that resveratrol could significantly inhibit the JAK1/STAT3 signal transduction pathway, down-regulate expressions of pJAK1 and pSTAT3 and reduce the phosphorylation of JAK1 and STAT3 in a dose-and time-dependent manner. It is concluded that the resveratrol can regulate signal transduction pathway and reduce the activation of JAK1/STAT3 tyrosine phosphorylation significantly, and therefore resveratrol shows chemotherapeutic potential to leukaemia.
Animals ; Antineoplastic Agents, Phytogenic ; pharmacology ; Down-Regulation ; Janus Kinase 1 ; genetics ; metabolism ; Leukemia L1210 ; genetics ; metabolism ; Mice ; Mice, Inbred BALB C ; Random Allocation ; STAT3 Transcription Factor ; genetics ; metabolism ; Signal Transduction ; drug effects ; Stilbenes ; pharmacology

OBJECTIVETo investigate the dual role of daphnetin in suppressing high mobility group box-1 protein (HMGB1) release and blocking HMGB1-induced inflammatory response.

METHODSMurine macrophage RAW264.7 cells were cultured in the presence of daphnetin, lipopolysaccharide (LPS), or both. HMGB1 release from the cells was determined using ELISA, and phosphorylations of JAK1/2 and of STAT1 were detected by Western blotting. Human monocytic THP-1 cells exposed to daphnetin, rhHMGB1, or both were examined for NO production using a NO detection kit, for the release of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and prostaglandin E2 (PGE2) using ELISA, and for expressions of iNOS, COX-2 and phosphorylated p38, ERK, and JNK with Western blotting.

RESULTSDaphnetin dose-dependently reduced the release of HMGB1 in RAW264.7 cells and suppressed rhHMGB1-induced iNOS and COX-2 expressions and release of TNF-α, IL-6, PGE2, and NO in THP-1 cells. Western blotting revealed that daphnetin significantly down-regulated the phosphorylations of JAK-STAT1 pathway in LPS-stimulated RAW264.7 cells but did not suppress the phosphorylations of MAPKs signaling pathway induced by rhHMGB1 in THP-1 cells.

CONCLUSIONDaphnetin can reduce the release of HMGB1 and suppress HMGB1-induced inflammatory response. In RAW264.7 cells, daphnetin inhibited LPS induced HMGB1 release is at least partly mediated by suppressing JAK-STAT1 signaling pathway activation.

Animals ; Cell Line ; Cyclooxygenase 2 ; metabolism ; Dinoprostone ; metabolism ; HMGB1 Protein ; metabolism ; Humans ; Inflammation ; metabolism ; Interleukin-6 ; metabolism ; Janus Kinase 1 ; metabolism ; Lipopolysaccharides ; Macrophages ; drug effects ; Mice ; Monocytes ; drug effects ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type II ; metabolism ; RAW 264.7 Cells ; STAT1 Transcription Factor ; metabolism ; Signal Transduction ; drug effects ; Tumor Necrosis Factor-alpha ; metabolism ; Umbelliferones ; pharmacology