Effects Of SP600125 Research Articles

Effects of SP600125 on Proliferation and Invasion of Human Cervical Cancer HeLa Cells

Effects of SP600125 on Proliferation and Invasion of Human Cervical Cancer HeLa Cells

Inhibition of c-Jun N-terminal kinase signaling promotes osteoblastic differentiation of periodontal ligament stem cells and induces regeneration of periodontal tissues

ObjectivesFew clinical treatments to regenerate periodontal tissue lost due to severe endodontic and periodontal disease have yet been developed. Therefore, the development of new treatment methods for the regeneration of periodontal tissue is expected. The purpose of this study was to investigate the effects of a c-Jun N-terminal kinase (JNK) inhibitor, SP600125, on the osteoblastic differentiation of periodontal ligament stem cells (PDLSCs) in vitro, and the function of SP600125 on the regeneration of alveolar bone in vivo. DesignAlizarin red S staining, quantitative RT-PCR, and western blotting analysis was performed to determine whether SP600125 affects osteoblastic differentiation of human PDLSCs (HPDLSCs) and bone-related intracellular signaling. The effect of SP600125 on the regeneration of alveolar bone was assessed by using a rat periodontal defect model. The healing of periodontal defects was evaluated using micro-CT scans and histological analysis. ResultsSP600125 promoted the osteoblastic differentiation such as Alizarin red S-positive mineralized nodule formation and the expression of osteoblast-related genes in HPDLSCs under osteogenic conditions. In addition, this inhibitor upregulated the BMP2 expression and the phosphorylation of Smad1/5/8 in HPDLSCs under the same conditions. The inhibition of Smad1/5/8 signaling by LDN193189 suppressed the SP600125-induced osteoblastic differentiation of HPDLSCs. Furthermore, the application of SP600125 promoted the regeneration of not only alveolar bone but also PDL tissue in periodontal defects. ConclusionThis study suggested that inhibition of JNK signaling promotes the osteoblastic differentiation of HPDLSCs through BMP2-Smad1/5/8 signaling, leading to the regeneration of periodontal tissues such as alveolar bone and PDL tissue.

Effects of SP600125 and hypothermic machine perfusion on livers donated after cardiac death in a pig allograft transplantation model

BackgroundHypothermic machine perfusion (HMP) improves the quality of donor livers for transplantation, both in animal models and in clinical practice. Treatment with SP600125, an inhibitor of c-Jun N-terminal kinase (JNK), can suppress the JNK signaling pathway to alleviate donor liver ischemia–reperfusion injury (IRI). We performed the present study with the objective of exploring the protective effects exerted by a combination of HMP and SP600125 on liver xenograft viability for donation after cardiac death (DCD) in a porcine model.Methods54 adult BAMA mini-pigs were randomly assigned to 5 groups, including sham, cold storage for 4 h (CS 4 h), CS 4 h + SP600125, CS 2 h + HMP 2 h, and CS 2 h + HMP 2 h + SP600125 groups. Donor livers in the CS 4 h and CS 4 h + SP600125 groups were conventionally cold preserved for 4 h, whereas donor livers in the CS 2 h + HMP 2 h and CS 2 h + HMP 2 h + SP600125 groups were cold preserved for 2 h and then treated with HMP for 2 h. The preservation and perfusion solutions contained SP600125 (20 µM). Follow-up was conducted for 5 days after liver transplantation to compare the surgical outcomes by means of serological examination, pathological results, and survival rate.ResultsThe most satisfactory outcome after liver transplantation was observed in the CS 2 h + HMP 2 h + SP600125 group, which presented with minimal damage of donor livers during 5 days’ follow-up. Additionally, serological examination, pathological results, and survival rate concurred in showing better results in the CS 2 h + HMP 2 h ± SP600125 group than in the CS 4 h ± SP600125 group.ConclusionHMP in combination with SP600125 has hepatoprotective properties and improves the quality and viability of porcine livers collected after DCD, thus improving prognosis after liver transplantation.

Inhibition of inflammation by SP600125 in cholestatic liver injury is dependent on the administration‑based exposure profile.

SP600125 is a classic inhibitor of c‑Jun‑N‑terminal kinase (JNK) that is widely used in numerous medicinal studies, but its administration regimen has yet to be optimized. In the present study, intraperitoneal (i.p.) and intragastric (i.g.) injections of 15mg/kg SP600125 was performed in mice to compare the inhibitory effect against JNK signalling in cholestasis induced by α‑naphthylisothiocyanate (ANIT). SP600125 at a dose of 15mg/kg administered by i.p. substantially decreased ANIT‑induced liver injury as observed by biochemical and histopathological examinations. The adaptation of bile acid synthesis was inhibited in the A‑SP‑i.p. group compared with that in the A‑SP‑i.g. group, as indicated by the expression analysis of CYP7A1 and CYP8B1. The transcription of the pro‑inflammatory factors IL‑6, IL‑1β, ICAM‑1 and IL‑10 supported the differential toxic responses. Western blot analysis revealed that JNK signalling activated by ANIT was inhibited more markedly in the A‑SP‑i.p. group than in the A‑SP‑i.g. group. The peak concentration and the AUC0‑24 of SP600125 in the A‑SP‑i.p. group were 5‑fold and 1.56‑fold higher, respectively, compared with those in the A‑SP‑i.g. group. These data indicated that i.p. administration of SP600125 produced a high plasma exposure profile, which directly determined its efficacy of blocking the JNK signalling. This effect of SP600125 on the JNK pathway may provide an optimized design for future invivo investigations.

DJ-1 inhibits autophagy activity of prostate cancer cells by repressing JNK-Bcl2-Beclin1 signaling.

The regulation of DJ-1 on AR signaling plays an important role in the pathogenesis of prostate cancer (PCa). DJ-1 could alter autophagy and regulate Beclin1-involved autophagy response through JNK-dependent pathway. JNK is known to mediate autophagy through Bcl2-Beclin1 complex. Therefore, this study aimed to investigate the significance of autophagy in DJ-1-modulated PCa cells. The current studies showed that DJ-1 overexpression in LNCaP decreased LC3 transformation and autophagosome formation. However, DJ-1 knockdown exerted the opposite effect. Moreover, DJ-1 silencing inhibited survival and promoted death in LNCaP, which was recovered by autophagy inhibition with 3-MA. In addition, DJ-1 overexpression inhibited the phosphorylation of JNK and Bcl2, and the dissociation of Beclin1 and Bcl2; while the effect of silencing DJ-1 was completely opposite. More important, JNK activated by anisimycin inhibited the proliferation and promoted death of DJ-1-overexpressed LNCaP while increasing LC3 transformation and LC3-puncta formation, but these results were reversed by the decrease of Beclin1 (by spautin-1). In contrast, when DJ-1 was silenced, the death of LNCaP, LC3 transformation, and LC3-puncta formation were inhibited by JNK inhibitor SP600125, which promoted cell proliferation. However, Bcl2 inhibition (by ABT737) reversed all the effects of SP600125. Our results suggested that DJ-1 in PCa cells could promote the growth of PCa through autophagy inhibition, and JNK-Bcl2-Beclin1 signaling played an important role in it. The study provided new insights into the role of DJ-1 in the development of PCa.

Anti-Inflammatory Effect of Feiyangchangweiyan Capsule on Rat Pelvic Inflammatory Disease through JNK/NF-κB Pathway.

Objectives In this study, we aimed to illustrate the preventive effect and possible mechanisms of Feiyangchangweiyan capsule (FYCWYC) on rat pelvic inflammatory disease (PID) model. Methods To construct the rat PID model, upper genital tract was infected by multipathogen, and then drugs were orally administered for 8 days. The histological examination, immunohistochemical analysis, and ELISA were carried out. Furthermore, Western blotting was used to analyze the expression of Akt, MAPKs, NF-κB p65, and IκB-α in uterus. Results As the results showed, infiltrations of neutrophils and lymphocytes in uterus were significantly suppressed, and IL-1β, IL-6, CXCL-1, and TNF-α were also reduced in a dose-dependent manner. We also found that FYCWYC inhibited apoptosis induced by infection. Furthermore, FYCWYC could block the infection-induced nuclear translocation of NF-κB. We found that FYCWYC treatment only decreased the phosphorylation of JNK induced by infection and had no effects on Akt and P38. Additional, the effects of SP600125, an inhibitor of phospho-JNK, were similar to the results of FYCWYC. Conclusions Taken together, our results demonstrated that FYCWYC had anti-inflammatory effect in pathogen-induced PID model, and the mechanism might be through inhibiting NF-κB nuclear translocation which is mediated by JNK.

Effects of SP600125 at various concentrations on proliferation and osteogenesis of human adipose-derived stem cells in vitro

Objective To elucidate the effects of SP600125 at different concentrations on the proliferation and osteo-differentiation of human adipose-derived stem cells (hASCs). Methods The hASCs harvested were cocultured with SP600125 at concentrations of 0 μmol/L, 1 μmol/L, 5 μmol/L and 10 μmol/L in growth medium (OM group) and in osteogenesis medium (OM group), respectively. The DNA quantitative assay was carried out to evaluate proliferation of the hASCs; flow cytometry was used to determine the effect of SP600125 on the cell cycles of hASCs; Alkaline phosphatase level (ALP) and calcium deposition tests were conducted to observe the effects of SP600125 at different concentrations on osteogenic differentiation of the hASCs. Results The proliferation of hASCs was inhibited by 42.1% when the cells were cocultured with SP600125 at the concentration of 10 μmol/L; the suppression decreased with decreased concentration of SP600125. The hASCs of phase G0/G1 in GM cocultured with SP600125 at the concentration of 10 μmol/L were more than those in GM cocultured with dimethylsulfoxide at the same concentration. ALP test revealed that after 10 days of culture in vitro the staining was more and more weakened and scattered and the ALP activity was more and more decreased with the increased concentration of SP600125. The extracellular calcium deposition of hASCs after 14 days of culture in vitro showed that the size and number of calcium nodules decreased with the increased concentration of SP600125. Conclusion SP600125 can suppress the proliferation and osteogenic differentiation of hASCs in vitro. Key words: Human; Adipocytes; Cell proliferation; Osteogenic differentiation; SP600125

LPS Cooperates with Poly-L-Arginine to Promote IL-6 and IL-8 Release via the JNK Signaling Pathway in NCI-H292 Cells.

Objective. Herein, we aimed to study the mechanism whereby poly-L-arginine (PLA) and lipopolysaccharide (LPS) can synergistically induce the release of interleukin-6 (IL-6) and IL-8 in NCI-H292 cells. Methods. NCI-H292 cells were divided into control, PLA, LPS, and PLA+LPS groups. At various time points, the phosphorylation of JNK in each group was measured by western blotting. Additionally, the productions of IL-6 and IL-8 were assessed using an enzyme-linked immunosorbent assay (ELISA). The effects of SP600125, an inhibitor of the JNK pathway, on the increase of p-JNK, IL-6, and IL-8 were also studied. Results. Our results showed that either PLA or LPS treatment alone can significantly increase the phosphorylation level of JNK in NCI-H292 cells. Of interest was the combined use of PLA and LPS that has a synergistic effect on the phosphorylation of JNK, as well as synergistically inducing the release of IL-6 and IL-8 in NCI-H292 cells. Furthermore, SP600125 significantly inhibited the activation of JNK signal, as well as reducing the productions of IL-6 and IL-8 in response to PLA+LPS stimulation. Conclusions. The JNK signaling pathway contributes to the release of IL-6 and IL-8, which is stimulated by the synergistic actions of PLA+LPS in NCI-H292 cells.

C-Jun N-terminal kinase inhibitor SP600125 enhances barrier function and elongation of human pancreatic cancer cell line HPAC in a Ca-switch model.

c-Jun N-terminal kinase (JNK), known as a stress-activated protein kinase, regulates normal epithelial biological processes, including assembly of adherens and tight junctions, and it is involved in the development of several cancers. The JNK inhibitor SP600125 enhances epithelial barrier function through modulation of tight junction molecules in normal human pancreatic epithelial cells. Furthermore, this JNK inhibitor suppresses the growth of human pancreatic cancer cells. However, the effects of SP600125 on the epithelial barrier in human pancreatic cancer cells remain unknown. In the present study, the JNK inhibitor SP600125 markedly enhanced the barrier function and cell elongation of well-differentiated human pancreatic cancer cell line HPAC in a Ca-switch model. The epithelial barrier function induced by SP600125 was regulated by phosphorylated β-catenin without changes in the tight junction molecules. The cell elongation induced by SP600125 was closely related to the expression of the F-actin-binding protein DrebrinE. These findings suggest that JNK is involved in the regulation of the epithelial barrier function and cell shape during remodeling of pancreatic cancer cells. The JNK inhibitor SP600125 may have potential as a therapeutic drug for pancreatic cancer via induction of differentiation.

Role of c-Jun N-terminal kinase (JNK) activation in micturition reflexes in cyclophosphamide (CYP)-induced cystitis in female rats.

c-Jun N-terminal kinase (JNK) is member of the mitogen-activated protein kinase (MAPK) family, activated through phosphorylation following cytokine exposure and stress. In this study, phosphorylation of JNK was examined in the urinary bladder with cyclophosphamide (CYP)-induced cystitis and the effects of SP600125, a selective inhibitor of phosphorylation of JNK, on urinary bladder function were assessed using conscious, open outlet, cystometry with continuous instillation of intravesical saline. We induced bladder inflammation in adult female Wistar rats by injecting CYP intraperitoneally to produce acute (150mg/kg; 4h), intermediate (150mg/kg; 48h), and chronic (75mg/kg; every third day for 10days) treatments. Western blotting of urinary bladder demonstrated a significant (p ≤ 0.01) increase (i.e., phosphorylation) in JNK activation with 4- and 48-h CYP-induced cystitis. Immunohistochemistry and image analyses demonstrated a significant (p ≤ 0.01) increase in JNK activation in the urothelium with 4- and 48-h CYP-induced cystitis. Blockade of JNK phosphorylation significantly (p ≤ 0.01) increased bladder capacity and intercontraction void intervals in CYP-treated rats (4 and 48h). Furthermore, blockade of JNK phosphorylation reduced (p ≤ 0.01) neuropeptide (substance P, calcitonin gene-related peptide) expression in the urinary bladder with CYP-induced cystitis (4 and 48h). In contrast, blockade of JNK phosphorylation was without effect on bladder function or neuropeptide expression in urinary bladder in control (no inflammation) rats. Blockade of JNK phosphorylation may represent a novel target for improving urinary bladder function with CYP-induced cystitis.

Dexmedetomidine-induced contraction involves phosphorylation of caldesmon by JNK in endothelium-denuded rat aortas.

Caldesmon, an inhibitory actin binding protein, binds to actin and inhibits actin-myosin interactions, whereas caldesmon phosphorylation reverses the inhibitory effect of caldesmon on actin-myosin interactions, potentially leading to enhanced contraction. The goal of this study was to investigate the cellular signaling pathway responsible for caldesmon phosphorylation, which is involved in the regulation of the contraction induced by dexmedetomidine (DMT), an alpha-2 adrenoceptor agonist, in endothelium-denuded rat aortas. SP600125 (a c-Jun NH2-terminal kinase [JNK] inhibitor) dose-response curves were generated in aortas that were pre-contracted with DMT or phorbol 12,13-dibutyrate (PDBu), a protein kinase C (PKC) activator. Dose-response curves to the PKC inhibitor chelerythrine were generated in rat aortas pre-contracted with DMT. The effects of SP600125 and rauwolscine (an alpha-2 adrenoceptor inhibitor) on DMT-induced caldesmon phosphorylation in rat aortic vascular smooth muscle cells (VSMCs) were investigated by western blot analysis. PDBu-induced caldesmon and DMT-induced PKC phosphorylation in rat aortic VSMCs was investigated by western blot analysis. The effects of GF109203X (a PKC inhibitor) on DMT- or PDBu-induced JNK phosphorylation in VSMCs were assessed. SP600125 resulted in the relaxation of aortas that were pre-contracted with DMT or PDBu, whereas rauwolscine attenuated DMT-induced contraction. Chelerythrine resulted in the vasodilation of aortas pre-contracted with DMT. SP600125 and rauwolscine inhibited DMT-induced caldesmon phosphorylation. Additionally, PDBu induced caldesmon phosphorylation, and GF109203X attenuated the JNK phosphorylation induced by DMT or PDBu. DMT induced PKC phosphorylation in rat aortic VSMCs. These results suggest that alpha-2 adrenoceptor-mediated, DMT-induced contraction involves caldesmon phosphorylation that is mediated by JNK phosphorylation by PKC.

Protective effect of SP600125, a JNK inhibitor, against nonalcoholic steatohepatitis

Protective effect of SP600125, a JNK inhibitor, against nonalcoholic steatohepatitis

JNK inhibitor SP600125 enhances TGF-β-induced apoptosis of RBE human cholangiocarcinoma cells in a Smad-dependent manner

Transforming growth factor β (TGF-β) signaling is pivotal for the progression of specific types of tumors at certain stages. However, the mechanism by which TGF-β is regulated by other factors remains unclear. In this study, the involvement of SP600125, an inhibitor of c-Jun N-terminal kinase (JNK), in TGF-β-induced apoptosis of the RBE human cholangiocarcinoma cell line was investigated. Exogenous TGF-β1 activated Smad and non‑Smad signaling pathways, including the JNK pathway in RBE cells, and induced apoptosis, which was inhibited by knockdown of Smad4 expression. SP600125 increased the TGF-β1‑induced phosphorylation of Smad2 and Smad3, which enhanced the TGF-β1‑induced transcriptional response and apoptosis in RBE cells. The effect of SP600125 on the transcriptional response and apoptosis was reduced by knockdown of Smad4 expression. In addition, TGF-β1‑induced apoptosis was abrogated using the pan-caspase inhibitor Z‑VAD-fmk. SP600125 promoted the TGF-β1‑induced caspase cleavage, while knockdown of Smad4 expression counteracted this effect. These results indicate that SP600125 enhances TGF-β-induced apoptosis of RBE cells through a Smad‑dependent pathway that involves Smad‑dependent caspase activation. SP600125 is hypothesized to be an ideal therapeutic candidate for treating human cholangiocarcinoma.

The effects of JNK pathway on isoflurane induced neuronal apoptosis in the hippocampi of neonatal rats

Objective To investigate the effects of the c-Jun N-terminal kinase (JNK)pathway on isoflurane induced neuronal apoptosis and the proteins expression of phospho-JNK, Bcl-2 and Bax in the hippocampi of neonatal rats. Methods Forty-eight neonatal rats at postnatal day 7 (P7) were randomly assigned into 4 groups: DMSO control group (group D), SP600125 control group (group SP30), isoflurane+ DMSO group (group Iso+ D), isoflurane+ SP600125 group (group Iso+ SP30). Rats were exposed to air (control group) or 1.1% isoflurane (isoflurane group) for 4 h. The JNK inhibitor SP600125 at 30 μg or 12% DMSO 5 μl was intraventricularly administered 20 min before the exposure. The brains of some rats in each group were perfused and embedded by paraffin 6 h after the exposure. Neuronal apoptosis in the hippocampi CA1 area was detected by TUNEL (n=6). The fresh hippocampi of other rats in each group were dissected 6 h after the exposure and the proteins expression of phospho-JNK, Bcl-2 and Bax were detected by Western blot (n=6). One way ANOVA were used for data analysis among groups. Results The number of TUNEL positive cells in the hippocampal CA1 regions in group Iso+ D (135.72±21.26 per mm2) increased by 5 folds compared with group D (24.07±1.35 per mm2) (P<0.01); while the number of apoptotic cells in group Iso+ SP30 (42.49±5.56 per mm2) decreased by 84%(P<0.05)compared with group Iso+ D. The expression of phospho-JNK p46 kd in group Iso+ D increased by 44.1%(P<0.01), while both phospho-JNK at p46kd and at p54kd in group Iso+ SP30 decreased significantly (P<0.05, P<0.01) compared with group Iso+ D. The protein expression of Bax increased 1.5 folds (P<0.05) and Bcl-2 decreased by 42.2% (P<0.05) in group Iso+ D compared to group D; while SP600125 significantly decreased expression of Bax (P<0.05) and increased expression of Bcl-2 (P<0.01). Conclusion JNK activation contributes to isoflurane-induced neuroapoptosis in the developing brain. Maintaining Bcl-2 expression and inhibiting Bax expression may be involved in the neuroprotective effects of SP600125. Key words: Apoptosis; Isoflurane; C-Jun N-terminal kinase; Hippocampus

Effect of SP600125 on proliferation of embryonic stem cell

SP600125 is an inhibitor of c-Jun NH2-terminal kinase (JNK), which plays a fundamental role in regulating animal development. Using SP600125 to deal with the mouse embryonic stem cells, it is revealed that the number of the ESC colonies decreased and the size became smaller. With treatment by SP600125, the proliferation of mouse ES cells is seriously inhibited for the cycle arrested in the G2/M phase, and the effect of SP600125 on the ES cells displays correlation of dose and time. The obtained results indicate that JNK may be an important regulator in the progression of cell cycle at the G2/M cell phase for the ES cells.

Neuroprotective effect of SP600125, an inhibitor of JNK on brain ischemia/reperfusion in rats

Objective To investigate the effect of SP600125 on cell apoptosis in hippocampal CA1 after cerebral ischemia/reperfusion (I/R) in rats and its possible mechanism.Methods 54 SD rats weighing 230 g-250 g were randomly divided into sham operation group (SH),I/R group and JNK inhibitor SP600125 group (SP).The rats received intracerebroventricularly DMSO(SH group),DMSO(I/R group) and SP600125(SP group,the use of DMSO solvent) 30 min before ischemia.Each group was divided into 3 subgroups according to reperfusion time 30 min,24 h and 72 h (6 animals for each subgroup).Global cerebral ischemia was induced by four-vessel occlusion in rats.Behavioral test was performed at 24 h and 72 h after cerebral ischemia/reperfusion.Bax and Bcl-2 positive pyramidal cells as well as apoptotic positive pyramidal cells in the CA1 were quantified in immunohistochemical stained or terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling(TUNEL) stained sections.Results Compared with SH group,cerebral I/R induced a decrease in standing times(4.8±2.0 vs 9.1±3.4,P＜0.05) and the beam-walking test scores(2.3±l.2 vs 3.5±0.9,P＜0.05).Immunohistochemistry results showed that after ischemia/reperfusion Hippocampal CA1 area Bcl-2 and Bax positive expression increased the number of pyramidal cells,24 h of reperfusion the number of pyramidal cells shows that the expression of positive to the peak(40.5±5.1)(P＜0.01),After I/R 24 h to 72 h,Positive expression to reduce the number of pyramidal cells (P＜0.05),With the IR group,SP group Bcl-2-positive pyramidal cells increased the number of (89.7±8.4)(P＜0.05),Baxpositive increase in the number of pyramidal cells less (40.5±2.3)(P＜0.05).Conclusions SP600125 protects hippocampal CA1 neurons from death during global brain ischemia/reperfusion injury through inhibition of JNK signal transduction pathway. Key words: Brain ischemia; Reperfusion injury; Apoptosis; JNK; Bcl-2; Bax

Enteral arginine modulates inhibition of AP-1/c-Jun by SP600125 in the postischemic gut

We previously demonstrated that enteral arginine increased c-Jun/activator protein-1 (AP-1) DNA-binding activity and iNOS expression in a rodent model of mesenteric ischemia/reperfusion (I/R). The objective of this study was to specifically investigate the role of AP-1 in arginine's deleterious effect on the postischemic gut. We hypothesized that AP-1 inhibition would mitigate the effects of arginine. Using a rodent model of mesenteric I/R we demonstrated that gut neutrophil infiltration, activity of c-Jun/AP-1, as well as iNOS expression were increased by I/R and further increased by arginine while lessened by inhibition of c-Jun using the pharmacologic c-Jun N-terminal kinase inhibitor, SP600125. Similar results were demonstrated using a cell culture model of oxidant stress in IEC-6 cells. Importantly, effects of SP600125 were comparable to those of c-Jun silencing. Lastly, the specific iNOS inhibitor, 1400W, had no effect on either AP-1 or c-Jun. In conclusion, SP600125 attenuated the activity of c-Jun/AP-1, iNOS expression, and neutrophil infiltration induced by arginine following mesenteric I/R. Our data suggest that AP-1 inhibition mitigates the injurious inflammatory effects of arginine in the postischemic gut. Further investigation into the pathologic role of enteral arginine in the postischemic gut is warranted.

Protective effects of SP600125 in a diet-induced rat model of non-alcoholic steatohepatitis

Objective. To investigate the protective effect of SP600125, a selective c-Jun N-terminal kinase inhibitor, in a diet-induced rat model of non-alcoholic steatohepatitis (NASH). Material and methods. Sprague–Dawley rats were randomly divided into three groups: a normal control group (NC group), a high-fat model group (HF group) and an SP600125 treatment group (SP group). All animals were subjected to a percutaneous superior mesenteric vein retention catheter operation and fed with a standard diet for 10 days. The HF group was then fed with an HF diet and treated with dimethyl sulfoxide while the SP group was fed with an HF diet and treated with SP600125 (50 mg/kg) once per day. Results. Feeding rats with an HF diet established a model of NASH, with varying degrees of hepatic steatosis and hepatic inflammation. SP600125 treatment substantially decreased the incidence of insulin resistance, reduced lipotoxicity, inhibited oxidative stress and alleviated hepatocellular injury. Conclusions. SP600125 has the potential to remarkably attenuate steatosis and inflammation and may be a novel therapeutic drug against NASH.

JNK mitogen-activated protein kinase limits calcium-dependent chloride secretion across colonic epithelial cells

Neuroimmune agonists induce epithelial Cl(-) secretion through elevations in intracellular Ca2+ or cAMP. Previously, we demonstrated that epidermal growth factor receptor (EGFR) transactivation and subsequent ERK MAPK activation limits secretory responses to Ca2+-dependent, but not cAMP-dependent, agonists. Although JNK MAPKs are also expressed in epithelial cells, their role in regulating transport function is unknown. Here, we investigated the potential role for JNK in regulating Cl(-) secretion in T(84) colonic epithelial cells. Western blot analysis revealed that a prototypical Ca2+-dependent secretagogue, carbachol (CCh; 100 microM), induced phosphorylation of both the 46-kDa and 54-kDa isoforms of JNK. This effect was mimicked by thapsigargin (TG), which specifically elevates intracellular Ca2+, but not by forskolin (FSK; 10 microM), which elevates cAMP. CCh-induced JNK phosphorylation was attenuated by the EGFR inhibitor, tyrphostin-AG1478 (1 microM). Pretreatment of voltage-clamped T(84) cells with SP600125 (2 microM), a specific JNK inhibitor, potentiated secretory responses to both CCh and TG but not to FSK. The effects of SP600125 on CCh-induced secretion were not additive with those of the ERK inhibitor, PD98059. Finally, in apically permeabilized T(84) cell monolayers, SP600125 potentiated CCh-induced K+ conductances but not Na+/K+ATPase activity. These data demonstrate a novel role for JNK MAPK in regulating Ca2+ but not cAMP-dependent epithelial Cl(-) secretion. JNK activation is mediated by EGFR transactivation and exerts its antisecretory effects through inhibition of basolateral K+ channels. These data further our understanding of mechanisms regulating epithelial secretion and underscore the potential for exploitation of MAPK-dependent signaling in treatment of intestinal transport disorders.

Effects of sp600125 on acetaldehyde stimulated hepatic stellate cells

肝星状细胞(HSC)的增殖与凋亡在肝纤维化的形成缮中起作十分重要的作用.乙醛刺激的HSC增殖是导致酒精性肝纤维化发生的关键因素 [1-2].丝裂原激活蛋白激酶(MAPK)包括细胞外调节蛋白激酶、c-Jun氨基末端激酶和p38,是HSC激活、增殖并导致肝纤维化发生的主要信号传导通路之一,其中,JNK信号传导通路参与了细胞增殖、分化以及凋亡的调控.我们既往对肝纤维化发病机制的研究结果证实,乙醛刺激的HSC中,p-JNK水平随JNK信号传导通路特异阻断剂SP600 125浓度增加而减少[3]。