Chronic Hyperinsulinism Induced Down-regulation of Insulin Post-Receptor Signaling Transduction in Hep G2 Cells

To study the regulatory effect of acute and chronic insulin treatmenton insulin post- re- ceptor signaling transduction pathway in a human hepatom a cell line (Hep G2 ) ,Hep G2 cells were incubated in the presence or absence of insulin with different concentrations in serum free m edia for16 h and then stim ulated with10 0 nmol/ L insulin for1m in.Protein levels of insulin receptor β- subunit(IRβ) ,insulin receptor substrate- 1(IRS- 1) and p85 subunit of phosphatidylinositol3- kinase(PI3- kinase) were determined in total cell lysates by Western- im munoblot.Phosphorylat- ed proteins IRβ,IRS- 1and interaction of PI3- kinase with IRS- 1were determ ined by im munopre- cipitation.Results showed that 1- min insulin stimulation rapidly induced tyrosine phosphorylation of IRβ and IRS- 1,which in turn,resulting in association of PI 3- kinase with IRS- 1.1- 10 0 nm ol/ L chronic insulin treatment induced a dose- dependent decrease in the protein level of IRβ and a slight decrease in the protein level of IRS- 1.There was a m ore marked reduction in the phospho- rylation of IRβ,IRS- 1,reaching a nadir of2 2 % (P<0 .0 1) and15 % (P<0 .0 1) of control lev- els,respectively,after16 h treatment with 10 0 nm ol/ L insulin.The association between IRS- 1 and PI3- kinase was decreased by6 6 % (P<0 .0 1) .There was no significant change in PI3- ki- nase protein levels. These data suggest that chronic insulin treatm ent can induce alterations of IRβ,IRS- 1and PI 3- kinase three early steps in insulin action,which contributes significantly to insulin resistance,and may account for desensitization of insulin action.

Signaling transduction pathways involved in basophil adhesion and histamine release

Background Little is known about basophil with respect to the different signaling transduction pathways involved in spontaneous, cytokine or anti-IgE induced adhesion and how this compares to IgE-dependent and IgE-independent mediator secretion. The purpose of the present study was to investigate the roles of β1 and β2 integrins in basophil adhesion as well as hosphatidylinositol 3-kinase （PI3K）, src-kinases and extracellular signal regulated kinase （ERK）1/2 in basophil adhesion and histamine release （HR）. Methods Basophils （purity of 10%-50%） were preincubated with anti-CD29 or anti-CD 18 blocking antibodies before used for adhesion study. Basophils were preincubated with the pharmacological inhibitors wortmannin, PP1, PD98059 before used for adhesion and HR study. Cell adherence to bovine serum albumin （BSA） or fibronectin （Fn） was monitored using cell associated histamine as a basophil marker and the histamine was measured by the glass fiber assay. Results Basophil spontaneous adhesion to Fn was inhibited by anti-CD29. Interleukin （IL）-3, granulocyte/macrophage colony stimulating factor （GM-CSF） induced adhesion to BSA was inhibited by anti-CD18. Wortmannin at 1 μmol/L and PP1 at 20 μmol/L strongly interfered with, whereas PD98059 at 50μmol/L weakly inhibited basophil spontaneous adhesion to Fn. One μmol/L wortmannin strongly inhibited IL-3, IL-5, GM-CSF and anti-IgE induced adhesion to BSA. PP1 at 20 μmol/L partly inhibited anti-IgE induced adhesion. Fifty μmol/L PD98059 marginally inhibited IL-5, weakly inhibited anti-IgE, partly inhibited GM-CSF induced adhesion. Wortmannin, PP1 and PD98059 inhibited anti-IgE （1：100 or 1：1000） induced basophil HR in a dose dependent manner. They inhibited calcium ionophore A23187 （10 μmol/L, 5 μmol/L） induced basophil HR in a dose dependent manner, but to different extend with PP1 being the most efficient. Conclusions Basophil spontaneous adhesion to Fn is mediated by β 1-integrins whereas cytokine induced adhesion to BSA is mediated by β 2-integrins. PI3K, src-kinases and ERK1/2 play distinct signaling roles in basophil adhesion and HR. PI3K is the key player while ERK1/2 is the weakest participant.

Signaling transduction by IgG receptors

To review and summarize literature regarding stimulatory and inhibitory signaling pathways from different types of Fc gamma r eceptors (FcγRs).Data source Articles were obtained from Medline from January 1 991 to April 2002. Study selection Over 100 English language papers and reviews pu blished over the last 11 years were selected.Results and Conclusions Stimulatory Fcγ receptors include Fc γRI, FcγRIIA, FcγRIIC, and FcγRIII A. They transduce signals through the imm unoreceptor tyrosine-based activation motif (ITAM) in subunits or in the cytopl asmic domain. Inhibitory Fcγ receptors, such as FcγRIIB, are single chain receptors, transducing signals through an immunoreceptor tyrosine-based inhibi tory motif (ITIM) in cytoplasmic domains. Stimulatory signals include protein ph osphorylation, increase in intracellular free calcium, the production of 1,4,5- triphosphate inositol (IP 3) and diacylglycerol (DAG) mainly through the Src-f amily kinases, phosphoinositide 3-kinase (PI3-K) and phospholipase C (PLC). In hibitory signaling has been implicated in the repression of the above activities as well as inhibition of B cell responses through Src homology 2-containing in ositol phosphatase (SHIP).

YWHAH activates the HMGA1/PI3K/AKT/mTOR signaling pathway by positively regulating Fra-1 to affect the proliferation of gastric cancer cells

Fos-related antigen 1(Fra-1)is a nuclear transcription factor that regulates cell growth,differentiation,and apoptosis.It is involved in the proliferation,invasion,apoptosis and epithelial mesenchymal transformation of malignant tumor cells.Fra-1 is highly expressed in gastric cancer(GC),affects the cycle distribution and apoptosis of GC cells,and participates in GC occurrence and development.However,the detailed mechanism of Fra-1 in GC is unclear,such as the identification of Fra-1-interacting proteins and their role in GC pathogenesis.In this study,we identified tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein eta(YWHAH)as a Fra-1-interacting protein in GC cells using co-immunoprecipitation combined with liquid chromatography-tandem mass spectrometry.Experiments showed that YWHAH positively regulated Fra-1 mRNA and protein expression,and affected GC cell proliferation.Whole proteome analysis showed that Fra-1 affected the activity of the high mobility group AT-hook 1(HMGA1)/phosphatidylinositol-4,5-bisphosphate 3-kinase(PI3K)/protein kinase B(AKT)/mechanistic target of rapamycin(mTOR)signaling pathway in GC cells.Western blotting and flow cytometry confirmed that YWHAH activated HMGA1/PI3K/AKT/mTOR signaling pathway by positively regulating Fra-1 to affect GC cell proliferation.These results will help to discover new molecular targets for the early diagnosis,treatment,and prognosis prediction of GC.

Scaffold proteins of cancer signaling networks: The paradigm of FK506 binding protein 51 (FKBP51) supporting tumor intrinsic properties and immune escape

Scaffold proteins are crucial regulators of signaling networks,and their abnormal expression may favor the development of tumors.Among the scaffold proteins,immunophilin covers a unique role as‘protein-philin’(Greek‘philin’=friend)that interacts with proteins to guide their proper assembly.The growing list of human syndromes associated with the immunophilin defect underscores the biological relevance of these proteins that are largely opportunistically exploited by cancer cells to support and enable the tumor’s intrinsic properties.Among the members of the immunophilin family,the FKBP5 gene was the only one identified to have a splicing variant.Cancer cells impose unique demands on the splicing machinery,thus acquiring a particular susceptibility to splicing inhibitors.This review article aims to overview the current knowledge of the FKBP5 gene functions in human cancer,illustrating how cancer cells exploit the scaffolding function of canonical FKBP51 to foster signaling networks that support their intrinsic tumor properties and the spliced FKBP51s to gain the capacity to evade the immune system.

The Antidepressant Mechanism of JiaWeiWenDan Decoction Regulating p38MAPK-ERK5 Signal Transduction Pathway

Objective: To investigate the anti-depression mechanism of JiaWeiWenDan Decoction in regulating p38MAPK-ERK5 signal transduction pathway. Methods: Depression model rats were randomly divided into Blank Control Group, Model Control Group, Chinese Medicine Treatment Group, and Western Medicine Treatment Group (hereinafter referred to as Blank Group, Model Group, Chinese Medicine Group, and Western Medicine Group), with 48 rats in each group. The mice were treated with p38MAPK-ERK5 on the 7th day, 14th day and 21st day, respectively, and the mice were treated for 28 days. The key targets and cytokines in p38MAPK-ERK5 signal transduction pathway were detected. Results: Compared with the Blank Group, the expression of p38MAPKmRNA in the hippocampus of the Model Group was increased. The Chinese Medicine Group and Western Medicine Group could reduce the expression of p38MAPK mRNA (P P P P Conclusion: The anti-inflammatory effect of JiaWeiWenDan Decoction may be related to the regulation of p38MAPK-ERK5 signaling pathway. With the advance of the treatment week, the best effect was obtained when the treatment was started on the 7th day of modeling.

Bibliometric analysis of the global research status and trends of mechanotransduction in cancer

BACKGROUND The development of cancer is thought to involve the dynamic crosstalk between the tumor cells and the microenvironment they inhabit.Such crosstalk is thought to involve mechanotransduction,a process whereby the cells sense mechanical cues such as stiffness,and translate these into biochemical signals,which have an impact on the subsequent cellular activities.Bibliometric analysis is a statistical method that involves investigating different aspects(including authors’names and affiliations,article keywords,journals and citations)of large volumes of literature.Despite an increase in mechanotransduction-related research in recent years,there are currently no bibliometric studies that describe the global status and trends of mechanotransduction-related research in the cancer field.AIM To investigate the global research status and trends of mechanotransduction in cancer from a bibliometric viewpoint.METHODS Literature on mechanotransduction in cancer published from January 1,1900 to December 31,2022 was retrieved from the Web of Science Core Collection.Excel and GraphPad software carried out the statistical analysis of the relevant author,journal,organization,and country information.The co-authorship,keyword cooccurrence,and keyword burst analysis were visualized with VOSviewer and CiteSpace.RESULTS Of 597 publications from 745 institutions in 45 countries were published in 268 journals with 35510 citation times.With 270 articles,the United States is a well-established global leader in this field,and the University of California system,the most productive(n=36)and influential institution(n=4705 citations),is the most highly active in collaborating with other organizations.Cancers was the most frequent publisher with the highest H-index.The most productive researcher was Valerie M.Weaver,with 10 publications.The combined analysis of concurrent and burst keywords revealed that the future research hotspots of mechanotransduction in cancer were related to the plasma membrane,autophagy,piezo1/2,heterogeneity,cancer diagnosis,and post-transcriptional modifications.CONCLUSION Mechanotransduction-related cancer research remains a hot topic.The United States is in the leading position of global research on mechano-oncology after almost 30 years of investigations.Research group cooperations exist but remain largely domestic,lacking cross-national communications.The next big topic in this field is to explore how the plasma membrane and its localized mechanosensor can transduce mechanical force through post-transcriptional modifications and thereby participate in cellular activity regulations and cancer development.

Na^(+)/K^(+)-ATPase:ion pump,signal transducer,or cytoprotective protein,and novel biological functions

Na^(+)/K^(+)-ATPase is a transmembrane protein that has important roles in the maintenance of electrochemical gradients across cell membranes by transporting three Na^(+)out of and two K^(+)into cells.Additionally,Na^(+)/K^(+)-ATPase participates in Ca^(2+)-signaling transduction and neurotransmitter release by coordinating the ion concentration gradient across the cell membrane.Na^(+)/K^(+)-ATPase works synergistically with multiple ion channels in the cell membrane to form a dynamic network of ion homeostatic regulation and affects cellular communication by regulating chemical signals and the ion balance among different types of cells.Therefo re,it is not surprising that Na^(+)/K^(+)-ATPase dysfunction has emerged as a risk factor for a variety of neurological diseases.However,published studies have so far only elucidated the important roles of Na^(+)/K^(+)-ATPase dysfunction in disease development,and we are lacking detailed mechanisms to clarify how Na^(+)/K^(+)-ATPase affects cell function.Our recent studies revealed that membrane loss of Na^(+)/K^(+)-ATPase is a key mechanism in many neurological disorders,particularly stroke and Parkinson's disease.Stabilization of plasma membrane Na^(+)/K^(+)-ATPase with an antibody is a novel strategy to treat these diseases.For this reason,Na^(+)/K^(+)-ATPase acts not only as a simple ion pump but also as a sensor/regulator or cytoprotective protein,participating in signal transduction such as neuronal autophagy and apoptosis,and glial cell migration.Thus,the present review attempts to summarize the novel biological functions of Na^(+)/K^(+)-ATPase and Na^(+)/K^(+)-ATPase-related pathogenesis.The potential for novel strategies to treat Na^(+)/K^(+)-ATPase-related brain diseases will also be discussed.

Impacts of PI3K/protein kinase B pathway activation in reactive astrocytes: from detrimental effects to protective functions

Astrocytes are the most abundant type of glial cell in the central nervous system.Upon injury and inflammation,astrocytes become reactive and undergo morphological and functional changes.Depending on their phenotypic classification as A1 or A2,reactive astrocytes contribute to both neurotoxic and neuroprotective responses,respectively.However,this binary classification does not fully capture the diversity of astrocyte responses observed across different diseases and injuries.Transcriptomic analysis has revealed that reactive astrocytes have a complex landscape of gene expression profiles,which emphasizes the heterogeneous nature of their reactivity.Astrocytes actively participate in regulating central nervous system inflammation by interacting with microglia and other cell types,releasing cytokines,and influencing the immune response.The phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT)signaling pathway is a central player in astrocyte reactivity and impacts various aspects of astrocyte behavior,as evidenced by in silico,in vitro,and in vivo results.In astrocytes,inflammatory cues trigger a cascade of molecular events,where nuclear factor-κB serves as a central mediator of the pro-inflammatory responses.Here,we review the heterogeneity of reactive astrocytes and the molecular mechanisms underlying their activation.We highlight the involvement of various signaling pathways that regulate astrocyte reactivity,including the PI3K/AKT/mammalian target of rapamycin(mTOR),αvβ3 integrin/PI3K/AKT/connexin 43,and Notch/PI3K/AKT pathways.While targeting the inactivation of the PI3K/AKT cellular signaling pathway to control reactive astrocytes and prevent central nervous system damage,evidence suggests that activating this pathway could also yield beneficial outcomes.This dual function of the PI3K/AKT pathway underscores its complexity in astrocyte reactivity and brain function modulation.The review emphasizes the importance of employing astrocyte-exclusive models to understand their functions accurately and these models are essential for clarifying astrocyte behavior.The findings should then be validated using in vivo models to ensure real-life relevance.The review also highlights the significance of PI3K/AKT pathway modulation in preventing central nervous system damage,although further studies are required to fully comprehend its role due to varying factors such as different cell types,astrocyte responses to inflammation,and disease contexts.Specific strategies are clearly necessary to address these variables effectively.

Phosphorylated protein chip combined with artificial intelligence tools for precise drug screening

We have developed a protein array system,named"Phospho-Totum",which reproduces the phosphorylation state of a sample on the array.The protein array contains 1471 proteins from 273 known signaling pathways.According to the activation degrees of tyrosine kinases in the sample,the corresponding groups of substrate proteins on the array are phosphorylated under the same conditions.In addition to measuring the phosphorylation levels of the 1471 substrates,we have developed and performed the artificial intelligence-assisted tools to further characterize the phosphorylation state and estimate pathway activation,tyrosine kinase activation,and a list of kinase inhibitors that produce phosphorylation states similar to that of the sample.The Phospho-Totum system,which seamlessly links and interrogates the measurements and analyses,has the potential to not only elucidate pathophysiological mechanisms in diseases by reproducing the phosphorylation state of samples,but also be useful for drug discovery,particularly for screening targeted kinases for potential drug kinase inhibitors.

Function of the CaMKII-ryanodine receptor signaling pathway in rabbits with left ventricular hypertrophy and triggered ventricular arrhythmia

BACKGROUND:Calcium calmodulin-dependent kinase II(CaMKII) can be more active in patients with left ventricular hypertrophy(LVH),which in turn causes phosphorylation of ryanodine receptors,resulting in inactivation and the instability of intracellular calcium homeostasis.The present study aimed to determine the effect of CaMKII-ryanodine receptor pathway signaling in rabbits with left ventricular hypertrophy and triggered ventricular arrhythmia.METHODS:Forty New Zealand rabbits were randomized into four groups(10 per group):sham group,LVH group,KN-93 group(LVH+KN-93),and ryanodine group(LVH+ryanodine).Rabbits in the LVH,KN-93,and ryanodine groups were used to establish a left ventricular hypertrophy model by the coarctation of the abdominal aorta,while those in the sham group did not undergo the coarctation.After eight weeks,action potentials(APs) were recorded simultaneously in the endocardium and epicardium,and a transmural electrocardiogram(ECG) was also recorded in the rabbit left ventricular wedge model.Drugs were administered to the animals in the KN-93 and ryanodine groups,and the frequency of triggered APs and ventricular tachycardia was recorded after the rabbits were given isoprenaline(1 μmol/L) and high-frequency stimulation.RESULTS:The frequency(animals/group) of triggered APs was 0/10 in the sham group,10/10 in the LVH group,4/10 in the KN-93 group,and 1/10 in the ryanodine group.The frequencies of ventricular tachycardia were 0/10,9/10,3/10,and 1/10,respectively.The frequencies of polymorphic ventricular tachycardia or ventricular fibrillation were 0/10,7/10,2/10,and 1/10,respectively.The frequencies of triggered ventricular arrhythmias in the KN-93 and ryanodine groups were much lower than those in the LVH group(P<0.05).CONCLUSIONS:KN-93 and ryanodine can effectively reduce the occurrence of triggered ventricular arrhythmia in rabbits with LVH.The CaMKII-ryanodine signaling pathway can be used as a new means of treating ventricular arrhythmia.

The SHP-2 tyrosine phosphatase:Signaling mechanisms and biological functions

Cellular biological activities are tightly controlled by intracellular signaling processes initiated by extracellular signals. Protein tyrosine phosphatases, which remove phosphate groups from phosphorylated signaling molecules, play equally important tyrosine roles as protein tyrosine kinases in signal transduction. SHP-2, a cytoplajsmic SH2 domain containing protein tyrosine phosphatase, is involved in the signaling pathways of a variety of growth factors and cytokines. Recent studies have clearly demonstrated that this phosphatase plays an important role in transducing signal relay from the cell surface to the nucleus, and is a critical intracellular regulator in mediating cell proliferation and differentiation.

Influence on Cellular Signal Transduction Pathway in Dairy Cow Mammary Gland Epithelial Cells by Galactopoietic Compound Isolated from Vaccariae segetalis

The galactopoietic mechanism of Vaccaria segetalis is still unknown. Understanding dibutyl phthalate （DBP） separated from Vaccaria segetalis on the expression of lactation signal transduction genes of mammary gland epithelial cells, including prlr, erα, akt1, socs2, pparγ and elf5, will be helpful to reveal the molecular mechanism. Western blot and qRT- PCR were used to study the change of prlr, erα, akt, socs2, pparγ, and elf5 expression at mRNA and protein level. Co- localization expression of prolactin receptor （PRLR） and estrogen receptor α （ERα） was observed by immunofluorescence; the expression changes of miRNAs （21, 125b, 143, and 195） and the secretion of β-casein and lactose were detected by qRT-PCR and RP-HPLC. The results showed that Vaccaria segetalis active compound had similar fuctions as estrogen and/or prolactin （PRL） in dairy cow mammary gland epithelial cells （DCMECs）, increased the expressions of prlr, erα, akt1, and elf5 genes, while repressed pparγ expressions. DBP promoted socs2 mRNA expression, but its protein expressions were repressed. Furthermore, both DBP and PRL could repress the expressions of miRNA-125b, miRNA-143 and miRNA- 195 in DCMECs. DBP could repress the expression of miRNA-21, while the influence of PRL on miRNA-21 was not certain. DBP could promote the lactation ability of DCMECs by regulating the ER and PRLR cellular signal transduction pathway.

Recent progress in the study of Hedgehog signaling

The Hedgehog （Hh） family of secreted signaling proteins plays a critical role in regulating the development of several tissues and organ systems. The ability of Hh proteins to exert their biological effects is regulated by a series of post-translational processes. These processes include an intramolecular cleavage, covalent addition of cholesterol and/or palmitate, and conversion into a multimeric freely diffusible form. The processing of Hh proteins affects their trafficking, potency, and ability to signal over several cell diameters. Here we review the current understanding of the Hh signaling mechanisms that govern the establishment of the Hh gradient and the transduction of the Hh signal in the light of recent data.

Sericin can reduce hippocampal neuronal apoptosis by activating the Akt signal transduction pathway in a rat model of diabetes mellitus

In the present study, a rat model of type 2 diabetes mellitus was established by continuous peritoneal injection of streptozotocin. Following intragastric perfusion of sericin for 35 days, blood glucose levels significantly reduced, neuronal apoptosis in the hippocampal CA1 region decreased, hippocampal phosphorylated Akt and nuclear factor kappa B expression were enhanced, but Bcl-xL/Bcl-2 associated death promoter expression decreased. Results demonstrated that sericin can reduce hippocampal neuronal apoptosis in a rat model of diabetes mellitus by regulating abnormal changes in the Akt signal transduction pathway.

p38 MAPK is a Component of the Signal Transduction Pathway Triggering Cold Stress Response in the MED Cryptic Species of Bemisia tabaci

Cold stress responses help insects to survive under low temperatures that would be lethal otherwise.This phenomenon might contribute to the invasion of some Bemisia tabaci cryptic species from subtropical areas to temperate regions.However,the molecular mechanisms regulating cold stress responses in whitefly are yet unclear.Mitogen-activated protein kinases（MAPKs）which including p38,ERK,and JNK,are well known for their roles in regulating metabolic responses to cold stress in many insects.In this study,we explored the possible roles of the MAPKs in response to low temperature stresses in the Mediterranean cryptic species（the Q-biotype）of the B.tabaci species complex.First,we cloned the p38 and ERK genes from the whitefly cDNA library.Next,we analyzed the activation of MAPKs during cold stress in the Mediterranean cryptic species by immuno-blotting.After cold stress,the level of phospho-p38 increased but no significant change was observed in the phosphorylation of ERK and JNK,thus suggesting that the p38 might be responsible for the defense response to low temperature stress.Furthermore,we demonstrated that：i）3 min chilling at 0°C was sufficient for the activation of p38 MAPK pathway in this whitefly;and ii）the amount of phosphorylated p38 increased significantly in the first 20 min of chilling,reversed by 60 min,and then returned to the original level by 120 min.Taken together,our results suggest that the p38 pathway is important during response to low temperature stress in the Mediterranean cryptic species of the B.tabaci species complex.

Roles of ABA Signal Transduction during Higher Plant Seed Development and Germination

ABA is one of the 5 phytohormones in higher plants, which is also the most important hormone that regulates higher plants in response to environmental stress, by ABA signal transduction. Understanding ABA signal transduction at the molecular level is crucial to biology and ecology, and rational breeding complied with corresponding eco-environmental changes. Great advancements have taken place over the past 10 years by application of the Arabidopsis experimental system. Many components involved in ABA signal transduction have been isolated and identified and a clear overall picture of gene expression and control for this transduction has become an accepted fact. On the basis of the work in our laboratory, in conjunction with the data available at the moment, the authors have attempted to integrate ABA signal transduction pathways into a common one and give some insights into the relationship between ABA signal transduction and other hormone signal transduction pathways, with an emphasis upon the ABA signal transduction during higher plant seed development. A future challenge in this field is that different experimental systems are applied and various receptors and genes need to be characterized through the utilization of microarray chips.

Rho/Rock signal transduction pathway is required for MSC tenogenic differentiation

Mesenchymal stem cell （MSC）-based treatments have shown promise for improving tendon healing and repair. MSCs have the potential to differentiate into multiple lineages in response to select chemical and physical stimuli, including into tenocytes. Cell elongation and cytoskeletal tension have been shown to be instrumental to the process of MSC differentiation. Previous studies have shown that inhibition of stress fiber formation leads MSCs to default toward an adipogenic lineage, which suggests that stress fibers are required for MSCs to sense the environmental factors that can induce differentiation into tenocytes. As the Rho/ROCK signal transduction pathway plays a critical role in both stress fiber formation and in cell sensation, we examined whether the activation of this pathway was required when inducing MSC tendon differentiation using rope-like silk scaffolds. To accomplish this, we employed a loss-of-function approach by knocking out ROCK, actin and myosin （two other components of the pathway） using the specific inhibitors Y-27632, Latrunculin A and blebbistatin, respectively. We demonstrated that independently disrupting the cytoskeleton and the Rho/ ROCK pathway abolished the expression of tendon differentiation markers and led to a loss of spindle morphology. Together, these studies suggest that the tension that is generated by MSC elongation is essential for MSC teno-differentiation and that the Rho/ROCK pathway is a critical mediator of tendon differentiation on rope-like silk scaffolds.

Taurine Inhibits Myocardial Fibrosis via PKC-ERK1/2 Signaling Pathways

Previous studies have demonstrated the important role of taurine in inhibiting proliferation of myofibrob lasts（myoFb） and myocardial fibrosis. However, the underlying mechanisms are unclear. The present study was de signed to shed light on this issue through exploring the signal pathways via in vitro experiments. Angiotension II （AngII） treatment significantly increased myoFb proliferation and the levels of collagens I and III（P〈0.05）, whereas taurine, PKCα（PKC： protein kinase C） specific inhibitor L-threo-dihydro-sphingosine（D4681）, ERK1/2 inhibitor （PD98095） abrogated myoFb proliferation and collagen levels（P〈0.05, P〈0.01, respectively）, and increased the G0/G1 phase rate and decreased S phase rate. Immunocytochemistry, confocal fluorescence staining and image analy sis showed that taurine could inhibit the translocation and expression of p-PKCαin membrane, and then inhibit nuc lear translocation and expression of p-ERK1/2. These results have statistically significant differences compared with those of AngII group（P〈0.01）. Western blot results also show that taurine could inhibit the protein expression of p-PKCα and p-ERK1/2. We used p-PKCα specific inhibitor D4681 in order to elucidate the relationship between p-PKCα and p-ERK1/2 in signal transduction pathways. Finally, the results show that the protein expression of p-ERK1/2 and nuclear translocation were suppressed in D4681 group.

Mitogen activated protein kinase signaling pathways participate in the active principle region of Buyang Huanwu decoction-induced differentiation of bone marrow mesenchymal stem cells

Our preliminary studies confirmed that an active principle region of Buyang Huanwu decoction, comprising alkaloid, polysaccharide, aglycon, glucoside and volatile oil, can induce bone marrow mesenchymal stem cell differentiation into neurons. Mitogen-activated protein kinase signaling was identified as one of the key pathways underlying this differentiation process. The present study shows phosphorylated extracellular signal-regulated protein kinase and phosphorylated p38 protein expression was increased after differentiation. Cellular signaling pathway blocking agents, PD98059 and SB203580, inhibited extracellular signal-regulated protein kinase and p38 in mitogen-activated protein kinase signaling pathways respectively, mRNA and protein expression of the neuronal marker, neuron specific enolase, and neural stem cell marker, nestin, were decreased in bone marrow mesenchymal stem cells after treatment with the active principle region of Buyang Huanwu decoction. Experimental findings indicate that, extracellular signal-regulated protein kinase and p38 in mitogen-activated protein kinase signaling pathways participate in bone marrow mesenchymal stem cell differentiation into neuron-like cells, induced by the active principle region of Buyang Huanwu decoction.