查找使用阿拉丁产品的科研文献

Duodenal GLP-1 signaling regulates hepatic glucose production through a PKC-δ-dependent neurocircuitry

Yang Mengliu,Wang Jinzhi,Wu Shaobo,Yuan Lei,Zhao Xiaodong,Liu Chaohong,Xie Jing,Jia Yanjun,Lai Yerui,Zhao Allan Zijian,Boden Guenther,Li Ling,Yang Gangyi

Intestinal glucagon-like peptide-1 (GLP-1) is a hormone that stimulates insulin secretion and acts as a neuropeptide to control glucose homeostasis, but little is known whether intestinal GLP-1 has any effect in the control of hepatic glucose production (HGP). Here we found that intraduodenal infusion of GLP-1 activated duodenal PKC- δ , lowered HGP and was accompanied by a decrease in hepatic expression of gluconeogenic enzymes and an increase in hepatic insulin signaling in rats. However, gut co-infusion of either the GLP-1 receptor antagonist Ex-9, or the PKC- δ inhibitor rottlerin with GLP-1, negated the ability of gut GLP-1 to lower HGP and to increase hepatic insulin signaling during clamps. The metabolic and molecular signal effects of duodenal GLP-1 were also negated by co-infusion with tetracaine, pharmacologic inhibition of N -methyl- d -aspartate receptors within the dorsalvagal complex, or hepatic vagotomy in rats. In summary, we identified a neural glucoregulatory function of gut GLP-1 signaling.

An Ingenane-Type Diterpene from Euphorbia kansui Promoted Cell Apoptosis and Macrophage Polarization via the Regulation of PKC Signaling Pathways

Xiaoyi Feng,Lizhong Wang,Li Pu,Jianchun Li,Hongmei Li,Dan Liu,Rongtao Li

Euphorbia kansui, a toxic Chinese medicine used for more than 2000 years, has the effect of “purging water to promote drinking” and “reducing swelling and dispersing modules”. Diterpenes and triterpenes are the main bioactive components ofE. kansui. Among them, ingenane-type diterpenes have multiple biological activities as a protein kinase C δ (PKC-δ) activator, which have previously been shown to promote anti-proliferative and pro-apoptotic effects in several human cancer cell lines. However, the activation of PKC subsequently promoted the survival of macrophages. Recently, we found that 13-hydroxyingenol-3-(2,3-dimethylbutanoate)-13-dodecanoate (compound A) fromE. kansuishowed dual bioactivity, including the inhibition of tumor-cell-line proliferation and regulation of macrophage polarization. This study identifies the possible mechanism of compound A in regulating the polarization state of macrophages, by regulating PKC-δ-extracellular signal regulated kinases (ERK) signaling pathways to exert anti-tumor immunity effects in vitro, which might provide a new treatment method from the perspective of immune cell regulation.

Sirtuin 1 represses PKC-ζ activity through regulating interplay of acetylation and phosphorylation in cardiac hypertrophy

Jingyan Li,Junying Huang,Jing Lu,Zhen Guo,Zhuoming Li,Hui Gao,Panxia Wang,Wenwei Luo,Sidong Cai,Yuehuai Hu,Kaiteng Guo,Luping Wang,Zhenzhen Li,Minghui Wang,Xiaolei Zhang,Peiqing Liu

Background and Purpose Activation of PKC-ζ is closely linked to the pathogenesis of cardiac hypertrophy. PKC-ζ can be activated by certain lipid metabolites such as phosphatidylinositol (3,4,5)-trisphosphate and ceramide. However, its endogenous negative regulators are not well defined. Here, the role of the sirtuin1-PKC-ζ signalling axis and the underlying molecular mechanisms were investigated in cardiac hypertrophy. Experimental Approach Cellular hypertrophy in cultures of cardiac myocytes, from neonatal Sprague-Dawley rats, was monitored by measuring cell surface area and the mRNA levels of hypertrophic biomarkers. Interaction between sirtuin1 and PKC-ζ was investigated by co-immunoprecipitation and confocal immunofluorescence microscopy. Sirtuin1 activation was enhanced by resveratrol treatment or Ad-sirtuin1 transfection. A model of cardiac hypertrophy in Sprague-Dawley rats was established by abdominal aortic constriction surgery or induced by isoprenaline in vivo . Key Results Overexpression of PKC-ζ led to cardiac hypertrophy and increased activity of NF-κB, ERK1/2 and ERK5, which was ameliorated by sirtuin1 overexpression. Enhancement of sirtuin1 activity suppressed acetylation of PKC-ζ, hindered its binding to phosphoinositide-dependent kinase 1 and inhibited PKC-ζ phosphorylation in cardiac hypertrophy. Consequently, the downstream pathways of PKC-ζ' were suppressed in cardiac hypertrophy. This regulation loop suggests a new role for sirtuin1 in mediation of cardiac hypertrophy. Conclusions and Implications Sirtuin1 is an endogenous negative regulator for PKC-ζ and mediates its activity via regulating the acetylation and phosphorylation in the pathogenesis of cardiac hypertrophy. Targeting the sirtuin1-PKC-ζ signalling axis may suggest a novel therapeutic approach against cardiac hypertrophy.

Chlorpyrifos Suppresses Neutrophil Extracellular Traps in Carp by Promoting Necroptosis and Inhibiting Respiratory Burst Caused by the PKC/MAPK Pathway

Qiaojian Zhang,Shengchen Wang,Shufang Zheng,Ziwei Zhang,Shiwen Xu

Neutrophil extracellular traps (NETs) are reticular structures formed by myeloperoxidase (MPO), histones, and neutrophil elastase (NE) that are released from neutrophils in response to pathogenic stimuli. Chlorpyrifos (CPF) is wildly used as an organophosphorus pesticide that causes a range of toxicological and environmental problems. Exposure to CPF can increase the production of neutrophils in carps, and this increase can be considered a biomarker of water pollution. To explore a relationship between NETs and CPF and its mechanism of influence, we treated neutrophils from the blood of carp with 1 μg/mL phorbol 12-myristate 13-acetate (PMA), 0.325 mg/L CPF, or 20 μM necrostatin-1 (Nec-1). The production of MPO and NETs was reduced in the CPF+PMA group compared with that in the PMA group. CPF can cause an increase in reactive oxygen species (ROS), while inhibiting respiratory burst caused by PMA stimulation. We found that the expression levels of protein-coupled receptor 84 (gpr84), dystroglycan (DAG), proto-oncogene serine/threonine kinase (RAF), protein kinase C (PKC), and mitogen-activated protein kinase 3 (MAPK3) in the CPF+PMA group were lower than those in the PMA group, indicating that the PKC-MAPK pathway was suppressed. The expression levels of cylindromatosis (CYLD), mixed lineage kinase domain-like pseudokinase (MLKL), receptor-interacting serine-threonine kinase 1 (RIP1), and receptor-interacting serine-threonine kinase 3 (RIP3) were increased, and the expression levels of caspase 8 were reduced by CPF, indicating that CPF may cause necroptosis. The addition of Nec-1 restored the number of NETs in the CPF+PMA group. The results indicate that CPF reduced the production of NETs by inhibiting respiratory burst and increasing necroptosis. The results contribute to the understanding of the immunotoxicological mechanism of CPF and provide a reference for comparative medical studies.

Suppression of Netrin-1 attenuates angiotension II-induced cardiac remodeling through the PKC/MAPK signaling pathway

Gaojun Wu,Zhengxian Wang,Peiren Shan,Shanjun Huang,Shuang Lin,Weijian Huang,Zhouqing Huang

Background Myocardial remodeling caused by angiotensin II (Ang II) is essential for the pathological process of heart failure. Netrin-1, which is an axonal guidance cue, has been shown to be involved in the inflammatory response, tumorigenesis, and angiogenesis in non-neuronal tissues. However, the role of Netrin-1 in cardiac remodeling has not been fully elucidated. Methods The rat cardiomyocyte cell line H9c2 and primary neonatal rat cardiomyocytes were treated with Ang II. Cells were transfected with siRNA to silence Netrin-1 expression. Real-time polymerase chain reaction and Western blot analysis were used to detect the markers for fibrosis, apoptosis, and hypertrophy in cardiomyocytes. An Annexin V-EGFP/PI cell apoptosis detection kit was used to measure the level of apoptosis caused by angiotensin II. Results We found that Netrin-1 expression was upregulated in the H9c2 cells and the neonatal rat cardiomyocytes stimulated by Ang II. The increased Netrin-1 expression was decreased by valsartan to block AT1R. Importantly, the application of Netrin-1 siRNA significantly alleviated the degrees of myocardial hypertrophy, fibrosis (reflected by Myhc, collagen I, and TGF-β) and apoptosis (reflected by the level of Caspase 3, Bax, and Bcl-2) induced by Ang II. In addition, the silencing of Netrin-1 substantially decreased the phosphorylation of PKCα, JNK, and P38. We treated H9c2 cells with LY317615, SP600125, and SB203580, inhibitors of PKCα, JNK, and P38, respectively, thereby resulting in a substantial decrease in hypertrophy, fibrosis, and apoptosis. Conclusions Ang II produces cardiac hypertrophy, fibrosis, and apoptosis through the upregulation of Netrin-1 and the activation of the AT1R/PKCα/MAPK (JNK, P38) pathway. Suppression of Netrin-1 can relieve Ang II-induced cardiac remodeling via inhibition of the PKCα/MAPK (JNK and P38) signaling pathway. Thus, Netrin-1 may be a novel therapeutic target for Ang II-mediated cardiac remodeling.

Suppression of A549 cell proliferation and metastasis by calycosin via inhibition of the PKC‑α/ERK1/2 pathway: An in vitro investigation Corrigendum in /10.3892/mmr.2016.4976

Xu‑Dong Cheng,Jun‑Fei Gu,Jia‑Rui Yuan,Liang Feng,Xiao‑Bin Jia

The migration and invasion of lung cancer cells into the extracellular matrix contributes to the high mortality rates of lung cancer. The protein kinase C (PKC) and downstream signaling pathways are important in the invasion and migration of lung cancer cells. Calycosin (Cal), an effector chemical from Astragalus has been reported to affect the recurrence and metastasis of cancer cells via the regulation of the protein expression of matrix metalloproteinases (MMPs). The inhibition of Cal on the migration and invasion of A549 cells was investigated in the present study. Cell viability and apoptosis assays were performed using MTT and flow cytometric analyses. A wound healing assay and Transwell invasion assay were performed to evaluate the effect of Cal on A549 cell migration and invasion. Invasion‑associated proteins, including MMP‑2, MMP‑9, E‑cadherin (E‑cad), integrin β1, PKC‑α and extracellular signal‑regulated kinase 1/2 (ERK1/2) were detected using western blotting. In addition, PKC‑α inhibitor, AEB071, and ERK1/2 inhibitor, PD98059, were used to determine the association between the suppression of PKC‑α /ERK1/2 and invasion, MMP‑2, MMP‑9, E‑cad and integrin β1. Cal was observed to suppress cell proliferation and induce apoptosis. There were significant differences between the phorbol‑12‑myristate‑13‑acetate (TPA)‑induced A549 cells treated with Cal and the untreated cells in the rates of migration and invasion. The levels of MMP‑2, MMP‑9, E‑cad and integrin β1 in the TPA‑induced A549 cells changed markedly, compared with the untreated cells. In addition, the suppression of Cal was affected by the PKC inhibitor, AEB071, an ERK1/2 inhibitor, PD98059. The results of the present study indicated that Cal inhibited the proliferation, adhesion, migration and invasion of the TPA‑induced A549 cells. The Cal‑induced repression of PKC‑α/ERK1/2, increased the expression of E‑Cad and inhibited the expression levels of MMP‑2, MMP‑9 and integrin β1, which possibly demonstrates the mechanism underlying the biological anticancer effects of Cal.

Chitooligosaccharide guanidine inhibits high glucose-induced activation of DAG/PKC pathway by regulating expression of GLUT2 in type 2 diabetic nephropathy rats

Hai Zhang,Shengsheng Zhang,Li Wang,Xiaofei Liu,Yuntang Wu

Previous results from our laboratory showed that chitosan biguanidine hydrochloride (CSGH) and chitooligosaccharide guanidine (COSG) could control glucose uptake by regulating the expression of glucose transporters (GLUTs) in vitro experiments. In this study, we try to delineate changes observed in activation of diacylglycerol (DAG)/protein kinase C- β (PKC- β ) pathway and GLUT2 in kidney. STZ-induced diabetic rats were administered COSG via daily intra-gastric gavage for 8 weeks. Obviously, COSG significantly attenuated fasting blood glucose and blood glucose level by modulating the over-expression of GLUT2 and the level of DAG as well. Immunohistological examination revealed that factors such as PKC- β and transforming growth factor- β (TGF- β ) diminished to various extents after treatment with COSG, which impinged on the synthesis of extracellular matrix (ECM) components like fibronectin (FN). As a result, high glucose-induced activation of DAG/PKC pathway is inhibited, which is associated with the concentration of glucose controlled by the expression of GLUT2 with the treatment of COSG.

Galangin protects gastric mucosa from indomethacin induced injury via scavenging ROS and inhibition of PKC, Akt, and NF κB protein expressions

Jingwen Gong,Yu Xie,Yinfen Tan,Hailong Li,Junqing Zhang

Purpose: To investigate the mechanism of action of galangin (GAL) against indomethacin (Indo)-induced gastric injury. Methods: Ten micromolar GAL with 2 mM Indo or 0.5 mM L-NAME or 2 mM propargylglycine were co-administered to human gastric mucosal epithelial cells GES-1 for 24 h. Cell viability assay and reactive oxygen species (ROS) test were conducted with commercial kits. Protein expressions of constitutive and inducible nitric oxide synthase (cNOS and iNOS, respectively), and cystathionine-γ-lyase (CSE) in GSE-1 cells were investigated by western blot. After 100 - 300 mg/kg, GAL was daily administered to rats for 5 days, and 30 mg/kg Indo was administered to induce gastric injury. Protein expressions of endothelial NOS (eNOS), iNOS, CSE, nuclear factor (NF)-κB, PKC, Akt, phospho-eNOS (Ser-1177), and phospho-eNOS (Thr-495) were investigated by western blot. Results: Galangin ameliorated the proliferative inhibitions of Indo, propargylglycine, and L-NAME on GSE-1 cells (p < 0.05), rapidly scavenged ROS, and increased cNOS protein expressions (p < 0.05). Galangin (300 mg/kg) inhibited protein expressions of iNOS (p < 0.01), NF-κB, Akt, and PKC (p < 0.05), inhibited the Ser-1177 and Thr 495 phosphorylation of eNOS, elevated eNOS and CSE protein expressions (p < 0.001). Conclusion: Galangin protects gastric mucosa from Indo by scavenging ROS and inhibiting protein expressions of Akt and PKC. The inhibition leads to Ser-1177 and Thr 495 dephosphorylation of eNOS, thereby prolonging eNOS activity. Besides, GAL inhibits iNOS-produced NO by inhibiting NF-κB to ameliorate the inflammatory reaction induced by Indo.

α-Glycerol monolaurate promotes tight junction proteins expression through PKC/MAPK/ATF-2 signaling pathway

Siyu Dai,Cunjie Li,Dagang Li,Hong Wang

Introduction: This study investigates the effects of α-GML on intestinal epithelial tight junction (TJ) protein expression and its molecular mechanisms. Recognizing the critical role of TJ proteins in intestinal barrier function and the potential of α-GML to enhance this barrier, we employ the IPEC-J2 cell model. Our aim is to validate the regulatory impact ofα-GML on TJ protein expression and elucidate the underlying signaling pathways, thereby offering new strategies for intestinal health maintenance.Methods: Utilized Data-Independent Acquisition (DIA) analysis to identify optimal targets of α-GML in modulating Tight Junction (TJ) protein expression. Treated cells with specific inhibitors of PKC and MAPK to assess their role in TJ regulation by α-GML. Co-treated cells with the MAPK inhibitor SCH772984 and α-GML to study the effects on p-ATF-2 expression. Evaluated the effects of SCH772984 and ATF-2 overexpression on the protein expression levels of phosphorylated ATF-2, ZO-1, and OCLN.Results: Revealed that α-GML’s modulation of TJ proteins might involve the PKC/MAPK signaling pathway, leading to ATF-2 phosphorylation. Both PKC and MAPK inhibitors reduced TJ protein expression (p < 0.05, p < 0.01 or p < 0.001), indicating their involvement in α-GML’s regulation. SCH772984 counteracted α-GML-induced upregulation of p-ATF-2 (p < 0.05), suggesting MAPK’s role in this process. Identified potential ATF-2 binding sites on ZO-1 and OCLN promoters. ATF-2 significantly enhanced ZO-1 promoter activity (p < 0.001). SCH772984 reduced phosphorylated ATF-2, ZO-1, and OCLN levels (p < 0.05 or p < 0.01), while ATF-2 overexpression rescued this decrease (p < 0.05 or p < 0.01), confirming ATF-2’s role in TJ protein upregulation via the MAPK pathway.Discussion: Our study indicated that α-GML enhanced the expression of TJ proteins through the PKC/MAPK/ATF-2 pathway, thereby enhancing the barrier function of intestinal epithelial cells.

Correction: α-Glycerol monolaurate promotes tight junction proteins expression through PKC/MAPK/ATF-2 signaling pathway

Siyu Dai,Cunjie Li,Dagang Li,Hong Wang

STC2 suppresses triple-negative breast cancer migration and invasion by inhibition on EMT and promotion on cell apoptosis

Lei Ruiwen,Yao Chaoling,Huang Renfeng,Wu Wanming,Ou Linyang,Yang Chuansheng

To investigate the effects of higher cellular stanniocalcin 2 (STC2) on suppressing the migration and invasion but promoting the apoptosis of triple-negative breast cancer (TNBC). STC2 in TNBC and the para-carcinoma tissues were analyzed by immunohistochemistry (IHC), while the mRNA level was measured by qPCR. Over-expressing or silencing STC2 was established in MDA-MB-231 cells. Epithelial mesenchymal transition (EMT) related proteins, cell migration, invasion, proliferation and apoptosis were detected. MDA-MB-231 with over-expressing or silencing STC2 were injected into nude mice to formatting tumors, and then EMT related proteins were measured by IHC. Lower STC2 expressed in TNBC tissues than in the para-carcinoma tissues. Silencing STC2 promoted EMT of TNBC cell MDA-MB-231, as well as cell migration, invasion and proliferation, but suppressed MDA-MB-231 apoptosis, while over-expressing STC2 had the opposite results, which might be related to PKC/PI3K/AKT/mTOR pathway. STC2 was the protective gene in TNBC, by suppressing migration and invasion to inhibit MDA-MB-231 cell EMT but promote cell apoptosis, in order to suppress TNBC progression.

DRD2-Mediated AMPK Ubiquitination Regulates the Occurrence of Hepatic Steatosis

Peng Ma,Hao Ou,Junze Cai,Yuanli Zhang,Yu Ou

Background & Aims G protein-coupled receptors (GPCRs) are important potential drug targets for the treatment of metabolic disorders. The D2 dopamine receptor (DRD2), a GPCR receptor, is a member of the dopamine receptor family. However, the role of DRD2 in regulating lipid metabolism, especially in hepatic steatosis, is unclear. Methods Eight-week male mice were fed HFHC/MCD to induce the MASH model. AAV2/8 containing the TBG promoter was used to knock down and overexpress DRD2 in mouse liver. Co-immunoprecipitation, Western lotting, immunofluorescence, and immunohistochemistry were used to investigate the mechanisms and screen DRD2 antagonists. Results The study found that activation of PKC leads to the elevation and internalisation of DRD2 in a high-fat environment. Knockdown of DRD2 in mouse liver can effectively interfere with the progression of MASH, while overexpression of DRD2 significantly aggravates the process of MASH. The study on the mechanism of DRD2 regulating lipid metabolism found that the internalisation of DRD2 could lead to dephosphorylation of pAKT (T308) by binding to β-arrestin2 and pAKT, thereby inducing ubiquitin-dependent degradation of AMPK and exacerbating steatosis. L-741626, a DRD2 antagonist, was found to interfere with the internalisation of DRD2 in a high-fat environment. It has been shown that L-741626 can treat MASH by regulating the AKT-AMPK signalling axis in vitro and in vivo. Conclusions In conclusion, this study demonstrated that internalisation of DRD2 in a high-fat environment aggravated MASH progression through the AKT-AMPK signalling axis. Furthermore, L-741626, as a DRD2 antagonist, has the potential to treat MASH.