基于p-Akt/p-GSK3β/GSK3β通路灵芝多糖对糖尿病大鼠心肌重构及保护作用研究

目的 探讨灵芝多糖（GLP）通过磷酸化丝氨酸/苏氨酸激酶（p-Akt）/磷酸化糖原合成酶激酶-3β(p-GSK3β)/糖原合成酶激酶-3β(GSK3β)通路对糖尿病大鼠心肌重构的影响。方法 于2020年12月至2021年12月，将90只SPF级雄性SD大鼠，按照随机数字表法分为对照组、模型组、GLP低、中、高剂量组，各18只。模型组和GLP各剂量组采用高脂高糖饲料喂养联合腹腔注射小剂量链脲佐菌素（STZ）溶液（30 mg/kg）诱导糖尿病大鼠模型，各组取建模成功的15只大鼠用于实验。GLP低、中、高剂量组均按照10 mL/kg体质量，灌胃浓度25、50、100 mg/kg GLP生理盐水溶液，对照组和模型组给予等体积生理盐水，每天1次，连续4周。比较各组大鼠血糖、体质量、左心室指数、心肌纤维化水平、心肌细胞凋亡水平、心肌组织中转化生长因子-β1(TGF-β1)、基质金属蛋白酶-2(MMP-2)、基质金属蛋白酶-9(MMP-9)水平以及p-Akt、丝氨酸/苏氨酸激酶（Akt）、p-GSK3β、GSK3β蛋白表达水平差异。结果 与对照组的血糖（4.45±0.38）mmol/L、左心室指数2...     

Fluoxetine Regulates Neurogenesis In Vitro Through Modulation of GSK-3β/β-Catenin Signaling

Background:

It is generally accepted that chronic treatment with antidepressants increases hippocampal neurogenesis, but the molecular mechanisms underlying their effects are unknown. Recently, glycogen synthase kinase-3 beta (GSK-3β)/β-catenin signaling was shown to be involved in the mechanism of how antidepressants might influence hippocampal neurogenesis.

Methods:

The aim of this study was to determine whether GSK-3β/β-catenin signaling is involved in the alteration of neurogenesis as a result of treatment with fluoxetine, a selective serotonin reuptake inhibitor. The mechanisms involved in fluoxetine’s regulation of GSK-3β/β-catenin signaling pathway were also examined.

Results:

Our results demonstrated that fluoxetine increased the proliferation of embryonic neural precursor cells (NPCs) by up-regulating the phosphorylation of Ser9 on GSK-3β and increasing the level of nuclear β-catenin. The overexpression of a stabilized β-catenin protein (ΔN89 β-catenin) significantly increased NPC proliferation, while inhibition of β-catenin expression in NPCs led to a significant decrease in the proliferation and reduced the proliferative effects induced by fluoxetine. The effects of fluoxetine-induced up-regulation of both phosphorylation of Ser9 on GSK-3β and nuclear β-catenin were significantly prevented by the 5-hydroxytryptamine-1A (5-HT_1A) receptor antagonist WAY-100635.

Conclusions:

The results demonstrate that fluoxetine may increase neurogenesis via the GSK-3β/β-catenin signaling pathway that links postsynaptic 5-HT_1A receptor activation.     

TGF-β/Smad3信号参与介导TRB3的促肿瘤作用

目的研究TRB3介导的促肿瘤作用与TGF-β/Smad3信号通路的关系。方法利用PCR扩增具有组成活性的Smad3突变体Smad3D,并将其构建至pcDNA3.1/Myc-His(-)B真核表达载体中。在稳定沉默TRB3的HepG2细胞中转染Smad3D-Myc表达质粒,利用G418筛选稳定表达Smad3D-Myc的细胞株。利用双荧光素酶报告基因系统检测3TP-lux转录活性。利用Transwell实验观察细胞侵袭能力变化。结果成功构建Smad3D突变体真核表达质粒。成功建立稳定沉默TRB3,同时稳定表达Smad3D突变体的HepG2细胞株。过表达Smad3D能明显增强3TP-lux转录活性,并在一定程度上逆转沉默TRB3后对肿瘤侵袭的抑制作用。结论 TGF-β/Smad3信号通路参与了TRB3促进肿瘤的作用。     

血府逐瘀合剂对PDGF-BB诱导的血管平滑肌细胞增殖、迁移及PI3K/AKT/GSK-3β/β-catenin信号通路的影响

摘要：目的:探究血府逐瘀合剂对血小板衍生生长因子（PDGF）-BB诱导的血管平滑肌细胞增殖、迁移及磷脂酰肌醇3-激酶/丝氨酸/苏氨酸蛋白激酶/糖元合成酶激酶3β/β-连环蛋白（PI3K/AKT/GSK-3β/β-catenin）信号通路的影响。方法:利用重组鼠PDGF-BB体外刺激大鼠胸大动脉平滑肌细胞A7R5诱导增殖、迁移模型,分为6组：对照组、PDGF-BB组、低剂量血府逐瘀合剂+PDGF-BB组、高剂量血府逐瘀合剂+PDGF-BB组、PI3K激活剂+PDGF-BB组、PI3K激活剂+高剂量血府逐瘀合剂+PDGF-BB组,CCK-8法检测A7R5细胞增殖活力;流式细胞术检测A7R5细胞周期;细胞划痕实验检测A7R5细胞迁移情况;免疫印迹检测A7R5细胞增殖、迁移相关蛋白及PI3K/AKT/GSK-3β/β-catenin信号通路相关蛋白。结果:与对照组比较,PDGF-BB组A7R5细胞增殖率、迁移面积、S期比例,PCNA、cyclin D1、MMP9蛋白及p-PI3K/PI3K、p-AKT/AKT、p-GSK-3β/GSK-3β、胞核β-catenin/总β-catenin蛋白比值显著增加,G0/G1期比例、E-cadherin蛋白显著减少（P＜0.05）;与PDGF-BB组比较,低、高剂量血府逐瘀合剂+PDGF-BB组A7R5细胞增殖率、迁移面积、S期比例,PCNA、cyclin D1、MMP9蛋白及p-PI3K/PI3K、p-AKT/AKT、p-GSK-3β/GSK-3β、胞核β-catenin/总β-catenin蛋白比值显著减少,G0/G1期比例、E-cadherin蛋白显著增加,且高剂量血府逐瘀合剂+PDGF-BB组优于低剂量血府逐瘀合剂+PDGF-BB组（P＜0.05）;与高剂量血府逐瘀合剂+PDGF-BB组比较,PI3K激活剂+高剂量血府逐瘀合剂+PDGF-BB组A7R5细胞增殖率、迁移面积、S期比例,PCNA、cyclin D1、MMP9蛋白,p-PI3K/PI3K、p-AKT/AKT、p-GSK-3β/GSK-3β、胞核β-catenin/总β-catenin蛋白比值显著增加,G0/G1期比例、E-cadherin蛋白显著减少（P＜0.05）。结论:血府逐瘀合剂可抑制PDGF-BB诱导的血管平滑肌细胞增殖、迁移,可能通过抑制PI3K/AKT/GSK-3β/β-catenin信号通路而实现。     

β3-肾上腺素受体激动剂的研究进展

摘要β     

新型减肥药β3-肾上腺素受体激动剂

β     

dalbinol通过ROS/Dvl/GSK-3β/β-catenin信号通路诱导人结肠癌细胞凋亡的作用机制研究

目的探讨天然产物dalbinol对人结肠癌HCT116细胞增殖和凋亡的影响及其作用机制。方法采用MTT法检测dalbinol对人结肠癌HCT116细胞的增殖抑制作用;利用Hoechst 33342荧光染色法观察细胞凋亡的形态学变化;应用流式细胞术检测细胞凋亡率和ROS水平;通过Western blot法检测Wnt/β-catenin信号通路及凋亡相关蛋白的表达情况。结果 dalbinol可抑制人结肠癌HCT116细胞的增殖,且呈剂量和时间依赖性,24、48和72 h的IC50分别为(4.8±0.53)、(2.5±0.43)和(0.6±0.22)μmol·L-1;Hoechst 33342染色观察到细胞皱缩、核固缩和染色质凝集等典型凋亡的形态学变化,同时dalbinol可剂量依赖性地提高细胞凋亡率,且能增加细胞内ROS水平;Western blot结果发现dalbinol通过下调抗凋亡蛋白Bcl-2和Mcl-1的表达水平,上调促凋亡蛋白Bax和Bim的表达,从而促进cleaved caspase-3和cleaved PARP活化裂解,进而诱导细胞凋亡;此外,dalbinol通过抑制Dvl-2和GSK3β(p S9)的蛋白表达,从而降低总的β-catenin和胞核β-catenin的表达,但胞质β-catenin无明显变化,最终下调Wnt/β-catenin通路下游靶蛋白c-Myc和Survivin的表达水平。结论dalbinol可抑制人结肠癌HCT116细胞增殖并诱导其凋亡,其分子机制可能与提高细胞内ROS水平和抑制Dvl/GSK-3β/β-catenin信号通路有关。     

藏红花素介导DKK3调控GSK-3β/β-catenin通路对阿尔兹海默症大鼠的认知改善作用

目的：探讨藏红花素（crocin）对阿尔兹海默症（Alzheimer’s disease,AD）小鼠认知能力的改善作用及机制。方法：SD大鼠海马区注射Aβ25-35建立AD模型，随机分为AD组、AD+L、M、H-crocin组（10、20、40 mg/kg）和AD+donepezil组（1 mg/kg盐酸多奈哌齐），腹腔注射治疗4周，另设置Sham组。采用避暗实验、水迷宫实验评估大鼠学习、记忆能力，ELISA测定大鼠血清Aβ含量，HE染色和Tunel染色确定大鼠海马区内病理改变及神经元细胞凋亡，免疫组化测定大鼠海马区Brdu、Dcx、NeuN表达，Western blot测定大鼠脑组织Aβ、DKK3、β-catenin、p-GSK-3β/GSK-3β、Caspase-3、Bax、Bcl-2蛋白表达。结果：与Sham组相比，AD组大鼠的学习、记忆能力下降，血清Aβ含量升高，且海马区的病理改变严重，神经元细胞凋亡增加，Brdu、Dcx、NeuN含量降低，Aβ、DKK3、pGSK-3β/GSK-3β、Caspase-3、Bax蛋白表达升高，β-catenin、Bcl-2蛋白表达降低（P<...     

Cadmium induces autophagy through ROS-dependent activation of the LKB1-AMPK signaling in skin epidermal cells

Cadmium is a toxic heavy metal which is environmentally and occupationally relevant. The mechanisms underlying cadmium-induced autophagy are not yet completely understood. The present study shows that cadmium induces autophagy, as demonstrated by the increase of LC3-II formation and the GFP-LC3 puncta cells. The induction of autophagosomes was directly visualized by electron microscopy in cadmium-exposed skin epidermal cells. Blockage of LKB1 or AMPK by siRNA transfection suppressed cadmium-induced autophagy. Cadmium-induced autophagy was inhibited in dominant-negative AMPK-transfected cells, whereas it was accelerated in cells transfected with the constitutively active form of AMPK. mTOR signaling, a negative regulator of autophagy, was downregulated in cadmium-exposed cells. In addition, cadmium generated reactive oxygen species (ROS) at relatively low levels, and caused poly(ADP-ribose) polymerase-1 (PARP) activation and ATP depletion. Inhibition of PARP by pharmacological inhibitors or its siRNA transfection suppressed ATP reduction and autophagy in cadmium-exposed cells. Furthermore, cadmium-induced autophagy signaling was attenuated by either exogenous addition of catalase and superoxide dismutase, or by overexpression of these enzymes. Consequently, these results suggest that cadmium-mediated ROS generation causes PARP activation and energy depletion, and eventually induces autophagy through the activation of LKB1-AMPK signaling and the down-regulation of mTOR in skin epidermal cells.     

Arsenic and chromium in drinking water promote tumorigenesis in a mouse colitis-associated colorectal cancer model and the potential mechanism is ROS-mediated Wnt/β-catenin signaling pathway

Exposure to carcinogenic metals, such as trivalent arsenic [As(III)] and hexavalent chromium [Cr(VI)], through drinking water is a major global public health problem and is associated with various cancers. However, the mechanism of their carcinogenicity remains unclear. In this study, we used azoxymethane/dextran sodium sulfate (AOM/DSS)-induced mouse colitis-associated colorectal cancer model to investigate their tumorigenesis. Our results demonstrate that exposure to As(III) or Cr(VI), alone or in combination, together with AOM/DSS pretreatment has a promotion effect, increasing the colorectal tumor incidence, multiplicity, size, and grade, as well as cell inflammatory response. Two-dimensional differential gel electrophoresis coupled with mass spectrometry revealed that As(III) or Cr(VI) treatment alone significantly changed the density of proteins. The expression of β-catenin and phospho-GSK was increased by treatment of carcinogenic metals alone. Concomitantly, the expression of NADPH oxidase1 (NOX1) and the level of 8-OHdG were also increased by treatment of carcinogenic metals alone. Antioxidant enzymes, such as superoxide dismutase (SOD) and catalase, were decreased. Similarly, in an in vitro system, exposure of CRL-1807 to carcinogenic metals increased reactive oxygen species (ROS) generation, the expression of β-catenin, phospho-GSK, and NOX1. Inhibition of ROS generation by addition of SOD or catalase inhibited β-catenin expression and activity. Our study provides a new animal model to study the carcinogenicity of As(III) and Cr(VI) and suggests that As(III) and Cr(VI) promote colorectal cancer tumorigenesis, at least partly, through ROS-mediated Wnt/β-catenin signaling pathway.     

Mitochondria,reactive oxygen species and cadmium toxicity in the kidney

The heavy metal cadmium accumulates in kidney cells, particularly those of the proximal tubular epithelium, and the damage this causes is associated with development of chronic kidney disease. One of the causative mechanisms of chronic kidney disease is thought to be oxidative stress. Cadmium induces oxidative stress, but the molecular mechanisms involved in the cell damage from oxidative stress in cadmium-induced chronic kidney disease are not well understood. Mitochondrial damage is likely, given that dysfunctional mitochondria are central to the formation of excess reactive oxygen species (ROS), and are known key intracellular targets for cadmium. Normally, ROS are balanced by natural anti-oxidant enzymes. When mitochondria become dysfunctional, for example, through long term exposure to environmental toxicants like cadmium, they produce less cell energy and more ROS. The imbalance between these ROS and the natural anti-oxidants creates the condition of oxidative stress. The outcomes of mitochondrial injury are manyfold: injured mitochondria perpetuate oxidative stress; the loss of mitochondrial membrane potential causes release of cytochrome-c and activation of caspase pathways that lead to apoptotic deletion of renal cells; and attempts by cells to remove dysfunctional mitochondria through autophagy lead to “autophagic cell death” or apoptosis. Three pathways of mitochondrial regulation (upstream signalling pathways, direct mitochondrial targeting, and downstream cell death effector pathways) are therefore all promising targets for effective anti-oxidant treatment of cadmium toxicity in the kidney.     

姜黄素通过抑制GSK-3β的活性防治AD的体外研究

目的探讨姜黄素(Curcumin)通过调节糖原合成激酶-3β(GSK-3β)的活性防治AD的机制。方法体外培养SHSY5Y细胞,转染pBACE1-mychis和pAPPswe,姜黄素处理细胞后,通过RT-PCR和Westernblot分别检测GSK-3β、β-链蛋白(β-catenin)和核内转录因子CyclinD1 mRNA水平和蛋白水平的表达情况,免疫荧光法检测GSK-3β和β-catenin的定位和阳性表达的变化,ELISA检测淀粉样蛋白(Aβ40/42)水平。结果Curcumin处理后,细胞内GSK-3β mRNA表达水平和蛋白水平都明显减弱;而GSK-3β的磷酸化形式GSK-3β-Ser9蛋白却明显增加,具有浓度-时间依赖性(P<0.05)。β-catenin和CyclinD1 mRNA表达水平和蛋白水平增加,呈浓度-时间依赖性(P<0.05)。免疫荧光染色结果不但证实了GSK-3β、β-catenin在细胞质内量的变化,而且还发现随着药物浓度的增加,β-catenin逐渐向细胞核内转移。Aβ40/42生成水平明显降低,呈浓度-时间依赖性(P<0.05)。结论GSK-3β是一个潜在性的AD治疗靶点,Curcumin能够通过抑制GSK-3β的活性来发挥防治AD的作用。     

Green tea polyphenol, (−)-epigallocatechin-3-gallate,induces toxicity in human skin cancer cells by targeting β-catenin signaling

The green tea polyphenol, (−)-epigallocatechin-3-gallate (EGCG), has been shown to have anti-carcinogenic effects in several skin tumor models, and efforts are continued to investigate the molecular targets responsible for its cytotoxic effects to cancer cells. Our recent observation that β-catenin is upregulated in skin tumors suggested the possibility that the anti-skin carcinogenic effects of EGCG are mediated, at least in part, through its effects on β-catenin signaling. We have found that treatment of the A431 and SCC13 human skin cancer cell lines with EGCG resulted in reduced cell viability and increased cell death and that these cytotoxic effects were associated with inactivation of β-catenin signaling. Evidence of EGCG-induced inactivation of β-catenin included: (i) reduced accumulation of nuclear β-catenin; (ii) enhanced levels of casein kinase1α, reduced phosphorylation of glycogen synthase kinase-3β, and increased phosphorylation of β-catenin on critical serine^45,33/37 residues; and (iii) reduced levels of matrix metalloproteinase (MMP)-2 and MMP-9, which are down-stream targets of β-catenin. Treatment of cells with prostaglandin E2 (PGE₂) enhanced the accumulation of β-catenin and enhanced β-catenin signaling. Treatment with either EGCG or an EP2 antagonist (AH6809) reduced the PGE₂-enhanced levels of cAMP, an upstream regulator of β-catenin. Inactivation of β-catenin by EGCG resulted in suppression of cell survival signaling proteins. siRNA knockdown of β-catenin in A431 and SCC13 cells reduced cell viability. Collectively, these data suggest that induction of cytotoxicity in skin cancer cells by EGCG is mediated by targeting of β-catenin signaling and that the β-catenin signaling is upregulated by inflammatory mediators.     

Reactive oxygen species mediate arsenic induced cell transformation and tumorigenesis through Wnt/β-catenin pathway in human colorectal adenocarcinoma DLD1 cells

Long term exposure to arsenic can increase incidence of human cancers, such as skin, lung, and colon rectum. The mechanism of arsenic induced carcinogenesis is still unclear. It is generally believed that reactive oxygen species (ROS) may play an important role in this process. In the present study, we investigate the possible linkage between ROS, β-catenin and arsenic induced transformation and tumorigenesis in human colorectal adenocarcinoma cell line, DLD1 cells. Our results show that arsenic was able to activate p47^phox and p67^phox, two key proteins for activation of NADPH oxidase. Arsenic was also able to generate ROS in DLD1 cells. Arsenic increased β-catenin expression level and its promoter activity. ROS played a major role in arsenic-induced β-catenin activation. Treatment of DLD1 cells by arsenic enhanced both transformation and tumorigenesis of these cells. The tumor volumes of arsenic treated group were much larger than those without arsenic treatment. Addition of either superoxide dismutase (SOD) or catalase reduced arsenic induced cell transformation and tumor formation. The results indicate that ROS are involved in arsenic induced cell transformation and tumor formation possible through Wnt/β-catenin pathway in human colorectal adenocarcinoma cell line DLD1 cells.     

The role of reactive oxygen species in arsenite and monomethylarsonous acid-induced signal transduction in human bladder cells: acute studies

Arsenicals are known to induce ROS, which can lead to DNA damage, oxidative stress, and carcinogenesis. A human urothelial cell line, UROtsa, was used to study the effects of arsenicals on the human bladder. Arsenite [As(III)] and monomethylarsonous acid [MMA(III)] induce oxidative stress in UROtsa cells after exposure to concentrations as low as 1 microM and 50 nM, respectively. Previous research has implicated ROS as signaling molecules in the MAPK signaling pathway. As(III) and MMA(III) have been shown to increase phosphorylation of key proteins in the MAPK signaling cascade downstream of ErbB2. Both Src phosphorylation (p-Src) and cyclooxygenase-2 (COX-2) are induced after exposure to 50 nM MMA(III) and 1 microM As(III). These data suggest that ROS production is a plausible mechanism for the signaling alterations seen in UROtsa cells after acute arsenical exposure. To determine importance of ROS in the MAPK cascade and its downstream induction of p-Src and COX-2, specific ROS antioxidants (both enzymatic and non-enzymatic) were used concomitantly with arsenicals. COX-2 protein and mRNA was shown to be much more influenced by altering the levels of ROS in cells, particularly after MMA(III) treatment. The antioxidant enzyme superoxide dismutase (SOD) effectively blocked both As(III)-and MMA(III)- associated COX-2 induction. The generation of ROS and subsequent altered signaling did lead to changes in protein levels of SOD, which were detected after treatment with either 1 microM As(III) or 50 nM MMA(III). These data suggest that the generation of ROS by arsenicals may be a mechanism leading to the altered cellular signaling seen after low-level arsenical exposure.     

Nilotinib ameliorates lipopolysaccharide-induced acute lung injury in rats

The present study aimed to investigate the effect of the new tyrosine kinase inhibitor, nilotinib on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats and explore its possible mechanisms. Male Sprague-Dawley rats were given nilotinib (10 mg/kg) by oral gavage twice daily for 1 week prior to exposure to aerosolized LPS. At 24 h after LPS exposure, bronchoalveolar lavage fluid (BALF) samples and lung tissue were collected. The lung wet/dry weight (W/D) ratio, protein level and the number of inflammatory cells in the BALF were determined. Optical microscopy was performed to examine the pathological changes in lungs. Malondialdehyde (MDA) content, superoxidase dismutase (SOD) and reduced glutathione (GSH) activities as well as nitrite/nitrate (NO₂⁻/NO₃⁻) levels were measured in lung tissues. The expression of inflammatory cytokines, tumor necrosis factor-α (TNF-α), transforming growth factor-β₁ (TGF-β₁) and inducible nitric oxide synthase (iNOS) were determined in lung tissues. Treatment with nilotinib prior to LPS exposure significantly attenuated the LPS-induced pulmonary edema, as it significantly decreased lung W/D ratio, protein concentration and the accumulation of the inflammatory cells in the BALF. This was supported by the histopathological examination which revealed marked attenuation of LPS-induced ALI in nilotinib treated rats. In addition, nilotinib significantly increased SOD and GSH activities with significant decrease in MDA content in the lung. Nilotinib also reduced LPS mediated overproduction of pulmonary NO₂⁻/NO₃⁻ levels. Importantly, nilotinib caused down-regulation of the inflammatory cytokines TNF-α, TGF-β₁ and iNOS levels in the lung. Taken together, these results demonstrate the protective effects of nilotinib against the LPS-induced ALI. This effect can be attributed to nilotinib ability to counteract the inflammatory cells infiltration and hence ROS generation and regulate cytokine effects.     

Valproic acid enhances protein l-isoaspartyl methyltransferase expression by stimulating extracellular signal-regulated kinase signaling pathway

Proteins are susceptible to various non-enzymatic post-translational modifications occurring during aging and in certain pathological states. The protein l-isoaspartyl methyltransferase (PIMT) is an enzyme that recognizes and repairs the abnormal l-isoaspartyl residues in proteins. Recently, we reported that PIMT expression was stimulated by the anti-epileptic drug valproic acid and that this was mediated through the glycogen synthase kinase-3 (GSK-3)/β-catenin pathway. In this study, to gain further insights into which of the signaling pathways activated by valproic acid regulate PIMT abundance, astrocytoma U-87 MG and neuroblastoma SH-SY5Y cells were treated with this drug to investigate the possible involvement of the extracellular-regulated kinase (ERK) pathway in PIMT induction. Valproic acid increased ERK1/2 phosphorylation on Thr202/Tyr204 and Thr185/Tyr187, respectively. Pharmacological inhibitors against the kinases Src, c-Raf, MEK1/2 and ERK1/2 abolished the ERK1/2 phosphorylation stimulated by valproic acid, thus preventing PIMT induction by the drug. Furthermore, MEK1/2 inhibition with U0126 blocked the higher phosphorylation of RSK-1 on Thr359/Ser363 and of GSK-3β on Ser9 as well as the increased expression of RSK-1, β-catenin and PIMT upon treatment with valproic acid. RSK-1 knockdown by interfering RNA abrogated the increased expression of RSK-1, β-catenin and PIMT as well as the induced phosphorylation of RSK-1 and GSK-3β due to valproic acid. Thus, our findings demonstrated that PIMT up-regulation by valproic acid required the activation of the ERK signaling pathway including RSK-1 the latter being responsible for inactivating GSK-3 and subsequently leading to β-catenin stabilization.