SERUM CONCENTRATIONS OF HYALURONIC ACID, PROCOLLAGEN TYPE III NH_2-TERMINAL PEPTIDE, AND LAMININ IN PATIENTS WITH CHRONIC CONGESTIVE HEART FAILURE

Objective To explore the role of serum fibrotic indices including hyaluronic acid （HA）, procollagen type Ⅲ NH2-terminal peptide （PCIIIP）, and laminin （LN） in assessing the severity of myocardial fibrosis in chronic congestive heart failure （CHF）. Methods Serum levels of HA, PCIIIP, and LN in 39 patients with CHF E [14 with New York Heart Association （NYHA） functional class II, 21 with class Ⅲ, 4 with class Ⅳ] and in 46 patients with NYHA functional class I were assessed by radioimmunoassay. Results The serum concentrations of HA, PCMP, and LN were 359.75 ± 84.59 μg/L, 77.88 ± 24. 67 μg/L, 86. 73 ± 23.90 μg/L in CHF group, and 211.60 ±54. 80 μg/L, 64.82 ±23.99 μg/L, 82. 26 ±23.98 μg/L in NYHA functional class Ⅰ group, respectively. The HA level was significantly higher in CHF patients as compared with NYHA functional class Ⅰ group （ P 〈 0.05 ）. However, no difference was found in the levels of PCIIIP and LN between CHF group and NYHA functional class Ⅰ group. The serum HA concentration was negatively correlated with left ventricular ejection fraction （ r = - 0.71, P 〈 0.05 ）. Conclusion Serum HA level may act as an indicator for myocardial fibrosis.

Specific effects of c-Jun NH2-terminal kinaseinteracting protein 1 in neuronal axons

c-Jun NH2-terminal kinase（JNK）-interacting protein 3 plays an important role in brain-derived neurotrophic factor/tropomyosin-related kinase B（Trk B） anterograde axonal transport. It remains unclear whether JNK-interacting protein 1 mediates similar effects, or whether JNK-interacting protein 1 affects the regulation of Trk B anterograde axonal transport. In this study, we isolated rat embryonic hippocampus and cultured hippocampal neurons in vitro. Coimmunoprecipitation results demonstrated that JNK-interacting protein 1 formed Trk B complexes in vitro and in vivo. Immunocytochemistry results showed that when JNK-interacting protein 1 was highly expressed, the distribution of Trk B gradually increased in axon terminals. However, the distribution of Trk B reduced in axon terminals after knocking out JNK-interacting protein 1. In addition, there were differences in distribution of Trk B after JNK-interacting protein 1 was knocked out compared with not. However, knockout of JNK-interacting protein 1 did not affect the distribution of Trk B in dendrites. These findings confirm that JNK-interacting protein 1 can interact with Trk B in neuronal cells, and can regulate the transport of Trk B in axons, but not in dendrites.

JNK1,JNK2,and JNK3 are involved in P-glycoprotein-mediated multidrug resistance of hepatocellular carcinoma cells

BACKGROUND:Multidrug resistance(MDR)is extremely common in hepatocellular carcinoma(HCC)and is a major problem in cancer eradication by limiting the efficacy of chemotherapy.Modulation of c-Jun NH2-terminal kinase(JNK)activation could be a new method to reverse MDR.However,the relationship between JNK activity and MDR in HCC cells is unknown.This study aimed to explore the relationship between MDR and JNK in HCC cell lines with different degrees of MDR.METHODS:A MDR human HCC cell line,SMMC-7721/ ADM,was developed by exposing parental cells to gradually increasing concentrations of adriamycin.The MTT assay was used to determine drug sensitivity.Flow cytometry was used to analyze the cell cycle distribution and to measure the expression levels of P-glycoprotein(P-gp)and MDR-related protein(MRP)-1 in these cells.JNK1,JNK2 and JNK3 mRNA expression levels were quantified by real-time PCR.Expression and phosphorylation of JNK1,JNK2,and JNK3 were analyzed by Western blotting.RESULTS:The MDR of SMMC-7721/ADM cells resistant to 0.05 mg/L adriamycin was mainly attributed to the overexpression of P-gp but not MRP1.In addition,these cells had a significant increase in percentage in the S phase,accompanied by a decrease in percentage in the G0/G1 phase,which is likely associated with a reduced ability for cell proliferation and MDR generation.We found that JNK1,JNK2,and JNK3 activities were negatively correlated with the degree of MDR in HCC cells.CONCLUSION:This study suggests that JNK1,JNK2,and JNK3 activities are negatively correlated with the degree of MDR in HCC cells.

Differential activation of mitogen-activated protein kinases by γ-irradi-ation in IEC-6 cells: Role of intracellular Ca^(2+)

Objective: To explore the effects of γ-irradiation on mitogen-activated protein kinases (MAPKs) and role of intracellular calcium in this event in intestinal epithelial cell line 6 (IEC-6 cells). Methods: After cultured rat IIEC-6 cells with or without the pretreatment of intracellular Ca2+ chelator were exposed to Y-ir-radiation of 6 Gy, the total and phosphorylated MAPKs in the cells were determined with Western blotting and apoptosis was examined with flow cytometry. Activities of Extracellular signal-regulated protein kinase (ERK) and p38 MAPK were determined by using immuoprecipitation followed by Western blotting. Results: In response to γ-irradiation, phosphorylation of ERK was not significantly observed, while the levels of phosphorylated c-Jun NH2-terminal kinase (JNK) and p38 MAPK were increased in 30 min and reached the peak 2 h after exposure to 6 Gy γ-irradiation, though the cell viability was significantly lowered 12 h. On the other hand, no obvious changes were seen in the total protein levels of ERK, JNK and p38 MAPK. Chelation of intracellular Ca2+ almost completely suppressed the JNK and p38 MAPK phosphorylation induced by γ-irradia-tion, but removal of external Ca2+ had no such effect. Activation of p38 MAPK, but not of ERK, was seen to have a correlation with γ-irradiation induced apoptosis. Conclusion: The results suggest that γ-irradiation is a potent activator for JNK and p38 MAPK, and Ca2+ mobilized from intracellular stores plays an important role in the activation of MAPKs and the induction of apoptosis in IEC-6 cells.

Effect of c-Jun NH2-terminal kinase-mediated p53 expression on neuron autophagy following traumatic brain injury in rats

Background Activation of c-Jun NH2-terminal kinase （JNK） has been implicated in neuron apoptosis as well as autophagy in response to various stressors after traumatic brain injury （TBI）. However, the underlying molecular pathway remains unclear. Our study assessed whether JNK-mediated p53 phosphorylation might be an important mechanism for enhancing neuron autophagy in response to TBI. Methods A total of 186 male Sprague-Dawley （SD） rats （300-350 g） were used in this study. By randomized block method rats were randomly divided into four groups： sham-operated （n=46）, TBI （n=60）, TBI ＋ dimethyl sulfoxide （DMSO） （n=40）, and TBI ＋ SP600125 （n=40）. JNK was treated with SP600125, a specific JNK inhibitor. JNK, p-P53, Beclin-1, damage-regulated autophagy modulator （DRAM） and p-bcl-2 were evaluated by Western blotting analysis. The cellular localization and expression of Beclin-1 and DRAM was observed by immunofluorescence and immunohistochemistry, and the expression of Beclin-l-Bcl-2/Bcl-xL complexes was evaluated by immunoprecipitation. Multiple-group comparisons were conducted using analysis of variance （ANOVA）. P values of less than 0.05 were considered statistically significant. Results It was observed that the expression of JNK, p-P53, Beclin-1, DRAM and p-bcl-2 was increasing after TBI, and the expression of Beclin-1 and DRAM was mainly located in the cytoplasm of neurons. But these were significantly inhibited in SP600125 group compared with sham group and TBI＋SP600125 group （P 〈0.05）. The expression of Beclin-l-Bcl-2/Bcl-xL complexes was reduced after TBI. Conclusion JNK-mediated p53 phosphorylation might be an important mechanism for enhancing neuron autophagy in response to TBI.

Antinociceptive Effect of Najanalgesin from Naja Naja Atra in a Neuropathic Pain Model via Inhibition of c-Jun NH2-terminal Kinase

Background： Najanalgesin, a toxin isolated from the venom ofNaja nqja atra, has been shown to exert significant analgesic effects in a neuropathic pain model in rats. However, the molecular mechanism underlying this protective effect ofnajanalgesin is poorly understood. The present study sought to evaluate the intracellular signaling pathways that are involved in the antinociceptive effect of najanalgesin on neuropathic pain. Methods： The antinociceptive properties of najanalgesin were tested in hind paw withdrawal thresholds in response to mechanical stimulation. We analyzed the participation of the mitogen-activated protein kinase p38, extracellular-regulated kinase （ERK）, and c-Jun N-terminal kinase （JNK） by western blot analysis. This inhibition of JNK was confirmed by immunohistochemistry. Results： The phosphorylation levels of INK （as well as its downstream molecule c-Jun）, p38, and ERK were significantly increased after injury. Najanalgesin only inhibited JNK and c-Jun phosphorylation but had no effect on either ERK or p38. This inhibition of JNK was confirmed by immunohistochemistry, which suggested that the antinociceptive effect of najanalgesin on spinal nerve ligation-induced neuropathic pain in rats is associated with JNK activation in the spinal cord. Conclusion： The antinociceptive effect of najanalgesin thnctions by inhibiting the JNK in a neuropathic pain model.

Inflammation-and stress-related signaling pathways in hepatocarcinogenesis

It has been established that cancer can be promoted and exacerbated by inflammation.Hepatocellular carcinoma(HCC) is the fifth most common cancer worldwide,and its long-term prognosis remains poor.Although HCC is a complex and heterogeneous tumor with several genomic mutations,it usually develops in the context of chronic liver damage and inflammation,suggesting that understanding the mechanism(s) of inflammation-mediated hepatocarcinogenesis is essential for the treatment and prevention of HCC.Chronic liver damage induces a persistent cycle of necroinflammation and hepatocyte regeneration,resulting in genetic mutations in hepatocytes and expansion of initiated cells,eventually leading to HCC development.Recently,several inflammation-and stress-related signaling pathways have been identified as key players in these processes,which include the nuclear factor B,signal transducer and activator of transcription,and stress-activated mitogen-activated protein kinase pathways.Although these pathways may suggest potential therapeutic targets,they have a wide range of functions and complex crosstalk occurs among them.This review focuses on recent advances in our understanding of the roles of these signaling pathways in hepatocarcinogenesis.

Efficient Monolithic Perovskite/Silicon Tandem Photovoltaics

Tunable bandgaps make halide perovskites promising candidates for developing tandem solar cells(TSCs),a strategy to break the radiative limit of 33.7%for single-junction solar cells.Combining perovskites with market-dominant crystalline silicon(c-Si)is particularly attractive;simple estimates based on the bandgap matching indicate that the efficiency limit in such tandem device is as high as 46%.However,state-of-the-art perovskite/c-Si TSCs only achieve an efficiency of~32.5%,implying significant challenges and also rich opportunities.In this review,we start with the operating mechanism and efficiency limit of TSCs,followed by systematical discussions on wide-bandgap perovskite front cells,interface selective contacts,and electrical interconnection layer,as well as photon management for highly efficient perovskite/c-Si TSCs.We highlight the challenges in this field and provide our understanding of future research directions toward highly efficient and stable large-scale wide-bandgap perovskite front cells for the commercialization of perovskite/c-Si TSCs.

Perovskite/Si tandem solar cells: Fundamentals, advances,challenges, and novel applications

The world record device efficiency of single-junction solar cells based on organic–inorganic hybrid perovskites has reached 25.5%.Further improvement in device power conversion efficiency(PCE)can be achieved by either optimizing perovskite films or designing novel device structures such as perovskite/Si tandem solar cells.With the marriage of perovskite and Si solar cells,a tandem device configuration is able to achieve a PCE exceeding the Shockley–Queisser limit of single-junction solar cells by enhancing the usage of solar spectrum.After several years of development,the highest PCE of the perovskite/Si tandem cell has reached 29.5%,which is higher than that of perovskite-and Si-based singlejunction cells.Here,in this review,we will(1)first discuss the device structure and fundamental working principle of both two-terminal(2T)and four-terminal(4T)perovskite/Si tandem solar cells;(2)second,provide a brief overview of the advances of perovskite/Si tandem solar cells regarding the development of interconnection layer,perovskite active layer,tandem device structure,and lightmanagement strategies;(3)third,discuss the challenges and opportunities for further developing perovskite/Si tandem solar cells.This review article,on the one hand,provides a comprehensive understanding to readers on the development of perovskite/Si tandems.On the other hand,it proposes various novel applications that may bring such tandems into the market in a near future.

Paxillin serine 178 phosphorylation in control of cell migration and metastasis formation through regulation of EGFR expression in breast cancer

Aim:Paxillin is a well-known multidomain scaffold protein that is involved in the regulation of cell-matrix adhesion dynamics,a process required for the tumor cell migration and invasion.Phosphorylation of the serine residue 178 requires c-Jun NH2-terminal kinase(JNK)activation,which occurs downstream of epidermal growth factor receptor(EGFR)-mediated signaling and drives cell migration.In this study,we investigated the significance of paxillin Ser178 phosphorylation in breast cancer progression.Methods:We employed the rat mammary carcinoma MTLn3 cell line with which we established stabile variants of both wild type and mutant GFP-paxillin constructs.With those,we next performed several in vitro assays including cell proliferation,migration and focal adhesion dynamics.Finally,we monitored the metastatic spread of both cell line variants in an othrotopic mouse model for breast cancer.Results:Here we show that expression of the phospho-defective mutant paxillinS178A in the metastatic mammary adenocarcinoma MTLn3 cell-line significantly decreased EGF-induced cell migration,which was correlated with impaired focal adhesion dynamics.Moreover,paxillinS178A attenuated lung metastasis formation in an orthotopic in vivo mammary gland tumor/metastasis model,demonstrating the importance of JNK-mediated paxillin phosphorylation in breast cancer progression.Expression of paxillinS178A caused a decrease in EGFR expression, ;while re-expression of EGFR in MTLn3-paxillinS178A cells fully restored EGF-driven cell motility and focal adhesion dynamics.Furthermore,re-expression of EGFR in MTLn3-paxillinS178A rescued spontaneous metastasis from breast to lung.Conclusion:Overall our data show an important role for JNK-mediated paxillin Ser178 phosphorylation in the regulation of EGFR expression and thereby,in EGF-driven cell migration and metastasis formation.