Clinical implications of forkhead box M1, cyclooxygenase-2, and glucose-regulated protein 78 in breast invasive ductal carcinoma

BACKGROUND Breast infiltrating ductal carcinoma(BIDC)represents the largest heterotypic tumor group,and an in-depth understanding of the pathogenesis of BIDC is key to improving its prognosis.AIM To analyze the expression profiles and clinical implications of forkhead box M1(FOXM1),cyclooxygenase-2(COX-2),and glucose-regulated protein 78(GRP78)in BIDC.METHODS A total of 65 BIDC patients and 70 healthy controls who presented to our hospital between August 2019 and May 2021 were selected for analysis.The peripheral blood FOXM1,COX-2,and GRP78 levels in both groups were measured and the association between their expression profiles in BIDC was examined.Additionally,we investigated the diagnostic value of FOXM1,COX-2,and GRP78 in patients with BIDC and their correlations with clinicopathological features.Furthermore,BIDC patients were followed for 1 year to identify factors influencing patient prognosis.RESULTS The levels of FOXM1,COX-2,and GRP78 were significantly higher in BIDC patients compared to healthy controls(P<0.05),and a positive correlation was observed among them(P<0.05).Receiver operating characteristic analysis demonstrated that FOXM1,COX-2,and GRP78 had excellent diagnostic value in predicting the occurrence of BIDC(P<0.05).Subsequently,we found significant differences in FOXM1,COX-2,and GRP78 levels among patients with different histological grades and metastasis statuses(with vs without)(P<0.05).Cox analysis revealed that FOXM1,COX-2,GRP78,increased histological grade,and the presence of tumor metastasis were independent risk factors for prognostic death in BIDC(P<0.001).CONCLUSION FOXM1,COX-2,and GRP78 exhibit abnormally high expression in BIDC,promoting malignant tumor development and closely correlating with prognosis.These findings hold significant research implications for the future diagnosis and treatment of BIDC.

Prostaglandin E1 protects hepatocytes against endoplasmic reticulum stress-induced apoptosis via protein kinase A-dependent induction of glucose-regulated protein 78 expression

AIM To investigate the protective effect of prostaglandin E1(PGE1) against endoplasmic reticulum(ER) stressinduced hepatocyte apoptosis, and to explore its underlying mechanisms.METHODS Thapsigargin(TG) was used to induce ER stress in the human hepatic cell line L02 and hepatocarcinomaderived cell line Hep G2. To evaluate the effects of PGE1 on TG-induced apoptosis, PGE1 was used an hour prior to TG treatment. Activation of unfolded protein response signaling pathways were detected by western blotting and quantitative real-time RTPCR. Apoptotic index and cell viability of L02 cells and Hep G2 cells were determined with flow cytometry and MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetrazolium] assay. RESULTS Pretreatment with 1 μmol/L PGE1 protected against TG-induced apoptosis in both L02 cells and Hep G2 cells. PGE1 enhanced the TG-induced expression of C/EBP homologous protein(CHOP), glucose-regulated protein(GRP) 78 and spliced X box-binding protein 1 at 6 h. However, it attenuated their expressions after 24 h. PGE1 alone induced protein and m RNA expressions of GRP78; PGE1 also induced protein expression of DNA damage-inducible gene 34 and inhibited the expressions of phospho-PKR-like ER kinase, phosphoeukaryotic initiation factor 2α and CHOP. Treatment with protein kinase A(PKA)-inhibitor H89 or KT5720 blocked PGE1-induced up-regulation of GRP78. Further, the cytoprotective effect of PGE1 on hepatocytes was not observed after blockade of GRP78 expression by H89 or small interfering RNA specifically targeted against human GRP78.CONCLUSION Our study demonstrates that PGE1 protects against ER stress-induced hepatocyte apoptosis via PKA pathwaydependent induction of GRP78 expression.

Role of Glucose-regulated Protein 78 in Early Brain Injury after Experimental Subarachnoid Hemorrhage in Rats

Early brain injury（EBI） plays a key role in the pathogenesis of subarachnoid hemorrhage（SAH）. This study investigated the role of glucose-regulated protein 78（GRP78） in EBI after SAH. Male Sprague-Dawley rats（n=108） weighing 260±40 g were divided into control, sham-operated, and operated groups. Blood was injected into the prechiasmatic cistern of rats in the operated group. Neurological scores, ultrastructures of neurons, apoptosis, and GRP78 expression in the hippocampus were examined using Garcia scoring system, transmission electron microscopy, terminal deoxynucleotidyl transferase-mediated d UTP nick-end labelling, and Western blotting at 1, 6, 12, 24, 48, and 72 h after SAH, respectively. The results showed that neurological scores were significantly decreased in the operated group as compared with those in control and sham-operated groups at 12, 24, 48, and 72 h. Metachromatin, chromatin pyknosis at the edge, endoplasmic reticulum swelling, and invagination of nuclear membrane were observed at 24 h in the operated group, indicating the early morphological changes of apoptosis. The number of apoptotic cells was significantly increased in the operated group as compared with that in control and sham-operated groups at 6, 12, 24, 48, and 72 h. The GRP78 protein expression levels in the operated group were significantly elevated at all time points and reached the peak at 12 h. GRP78 expression was positively associated with apoptosis cells and negatively with neurological scores. In conclusion, EBI was demonstrated to occur after SAH and GRP78 was involved in the development of EBI after SAH.

糖调节蛋白78在大鼠肠源性内毒素血症促进肝硬化形成中的作用

目的:探讨糖调节蛋白78(GRP78)在大鼠肠源性内毒素血症(IETM)促进肝硬化形成过程中的作用。方法:51只雄性Wistar大鼠随机分为肝硬化模型4周组、6周组、8周组及同期正常对照组。采用复合致病因素法诱导大鼠肝硬化,HE染色和VG染色分别观察肝损伤和肝纤维化情况;RT-PCR法和免疫组化法分别检测肝组织GRP78 mRNA及蛋白表达;同时测定血浆中丙氨酸氨基转移酶(ALT)、内毒素、肿瘤坏死因子-α(TNF-α)、同型半胱氨酸(HCY)以及肝组织匀浆中TNF-α、丙二醛(MDA)、Ⅲ型前胶原(PⅢP)水平。结果:(1)随病程进展,各模型组血浆中ALT、内毒素、TNF-α、HCY以及肝组织中GRP78 mRNA、蛋白表达水平、MDA、TNF-α、PⅢP含量和肝组织纤维化指数均逐渐升高并显著高于正常对照组(P<0.05)。(2)血浆中升高的内毒素水平分别与GRP78蛋白、血浆MDA和HCY水平以及肝纤维化指数呈显著正相关(P<0.01);表达增高的GRP78蛋白分别与血浆MDA和HCY水平以及肝纤维化指数呈显著正相关(P<0.01)。结论:GRP78可能在肝硬化形成过程中发挥重要作用;内质网应激很可能是IETM促进肝纤维化乃至肝硬化发生的重要机制。

葡萄糖调节蛋白78在复合致病因素诱导的大鼠肝肺综合征中的作用

目的:探讨葡萄糖调节蛋白78(GRP78)在大鼠肝肺综合征发病中的作用及其与肠源性内毒素血症的关系。方法:Wistar大鼠被随机分为4周组、6周组和8周组3个时点,采用复合致病因素法制备大鼠肝硬化合并肝肺综合征(HPS)模型,并设标准饮食的正常大鼠作为对照组。采用HE染色观察肺组织病理变化;测定血浆中丙氨酸氨基转移酶(ALT)、内毒素、TNF-α和肺组织匀浆中的TNF-α、丙二醛(MDA)的含量。Western blotting和RT-PCR法检测肺组织标本中GRP78蛋白和mRNA表达水平。结果:模型组动物血浆内毒素含量随病程进展逐渐增高;肺组织中GRP78蛋白和mRNA的表达随HPS进展逐步增高,且各时点间的表达有显著差异(P<0.05);血浆内毒素与升高的GRP78蛋白水平间呈高度正相关(P<0.01)。血浆ALT和TNF-α含量以及肺组织匀浆中TNF-α和MDA含量随病程进展逐渐增高;血浆内毒素含量以及肺组织中GRP78蛋白分别与血浆TNF-α和肺组织中TNF-α、MDA的含量呈高度正相关(P<0.01)。在各时点,模型组动物血浆TNF-α含量、肺组织匀浆TNF-α、GRP78蛋白及mRNA均显著高于正常对照组(P<0.05)。在第6周和第8周,模型组动物血浆内毒素和ALT的含量以及肺组织匀浆中MDA的含量均显著高于正常对照组(P<0.05)。结论:肝硬化时形成的肠源性内毒素血症作为内质网应激的重要应激原,通过氧化应激激活肺组织的内质网应激反应导致GRP78表达增高,很可能是HPS发病的重要机制。

miR-340通过靶向GRP78促进结直肠癌细胞凋亡并抑制其增殖、迁移和侵袭

miR-340能够促进癌细胞的增殖和侵袭,但是在结直肠癌中miR-340如何调控癌症的发生与发展鲜有报道。本研究探究miR-340在结直肠癌细胞中的生物学功能和靶基因调控机制。首先通过RT-qPCR检测不同的结直肠癌细胞株中miR-340的表达水平,再利用过表达和抑制miR-340,分别转染COLO-205细胞,以CCK-8检测细胞的增殖能力,Transwell法检测细胞的迁移和侵袭能力,流式细胞技术检测细胞的凋亡和细胞周期分布;最后通过生物信息学预测miR-340的靶基因,荧光素酶报告基因及Western印迹分析进行验证。结果显示,miR-340在COLO-205细胞中低表达,与对照组比较,细胞的增殖、迁移和侵袭在过表达miR-340转染组显著受到抑制,在抑制miR-340组中却被促进(P<0.01)。流式细胞检测结果显示,过表达miR-340转染组细胞凋亡比例显著升高,而抑制miR-340组中凋亡比例却降低(P<0.01)。过表达miR-340转染组细胞生物信息学分析结果显示,葡萄糖调节蛋白78(glucose regulated protein 78 kD, GRP78)的3′UTR上有miR-340-5p的结合位点,并且荧光素酶活性在转染过表达miR-340组中显著降低(P<0.01);Western印迹结果同样表明,过表达miR-340能够抑制GRP78的表达,而抑制miR-340,GRP78的表达抑制解除。综上所述,miR-340能够直接靶向GRP78来促进COLO-205细胞的凋亡,并抑制其增殖、迁移和侵袭。

胃癌中葡萄糖调节蛋白78的表达及其临床病理学意义

目的检测葡萄糖调节蛋白78(GRP78)在胃癌组织中的表达,分析其临床病理学意义,探讨GRP78在胃癌发生发展中的作用。方法收集48例不同临床分期及不同分化程度胃腺癌及28例癌旁正常胃黏膜组织标本,分别应用RT-PCR、Western Blotting和免疫组化检测GRP78 mRNA和蛋白质的表达。结果与正常胃黏膜组织相比,胃癌组织中GRP78 mRNA及蛋白表达水平显著增加(P<0.05)。免疫组化检测GRP78阳性表达定位于胞浆,在正常胃粘膜组织中GRP78阳性表达率为10.7%(3/28),高、中分化与低分化胃癌组织阳性表达率分别为59.4%(19/32)和93.8%(15/16);直径≥5 cm的胃癌组织中GRP78阳性表达率(88.9%,16/18)高于直径<5 cm的胃癌组织(60%,18/30),Ⅲ、Ⅳ期(TNM分期)病例胃癌组织中GRP78阳性表达率(90.5%,19/21)高于Ⅰ、Ⅱ期病例(55.6%,15/27);5年内病情复发或者死亡病例胃癌组织中GRP78阳性表达率(82.8%,24/29)高于5年内病情无复发病例(52.6%,10/19);淋巴结转移胃癌组织中GRP78阳性表达率(96.2%,25/26)明显高于非淋巴结转移胃癌组织(40.9%,9/22),各组间差异均具有统计学意义(P<0.05)。结论 GRP78在胃癌组织中高表达,其表达水平与胃癌肿瘤大小、分化程度、淋巴结转移、临床分期及预后密切相关。

葡萄糖调节蛋白GRP78与HBV的PreS1相互作用位点的初步研究

目的:初步研究78 k D的葡萄糖调节蛋白(the 78 k D glucose-regulated protein,GRP78)与乙型肝炎病毒(hepatitis B virus,HBV)的前S1蛋白(Pre S1)的相互作用位点。方法:利用PCR技术扩增GRP78的基因,将扩增的目的基因克隆至p W28载体质粒,在大肠杆菌(Escherichia coli,E.coli)B834中表达,经过镍离子亲和层析柱纯化GRP78蛋白;将Pre S1 3个截短片段的重组质粒(p GST-Pre S1-X1/X2/X3)在B834中表达后,经过GST亲和层析柱纯化相应蛋白;利用蛋白质体外结合实验(pull down)、微量热泳动(microscale thermophoresis,MST)检测GRP78与Pre S1 3个截短片段的相互作用。结果:成功构建重组质粒p W28-GRP78;获得GRP78蛋白及Pre S1 3个截短片段的融合蛋白;pull down及MST实验验证了GRP78可以与Pre S1的3个片段结合,且GRP78与GST-Pre S1-X1结合效果最好。结论:利用分子克隆技术及蛋白质表达纯化技术,获得GRP78蛋白及Pre S1截短片段的融合蛋白,并初步筛选了Pre S1与GRP78的相互作用位点,为后续研究打基础。

葡萄糖调节蛋白78在大鼠肠缺血再灌注损伤中的表达及其意义

目的:观察大鼠肠缺血再灌注损伤(intestine ischemia reperfusion injury,IIRI)过程中肠黏膜的组织损伤和细胞凋亡及内质网(endoplasmic reticulum,ER)分子伴侣葡萄糖调节蛋白78(glucose regulated protein 78 kD,GRP78)的表达变化,并探讨ER应激在肠IIRI中的作用及机制。方法:45只雄性SD大鼠随机分成9组:缺血再灌注0、1、3、6、12、24、48、72 h组,以及假手术对照组,每组5只。实验组均用无创性动脉夹夹闭肠系膜上动脉1 h后实施再灌注来建立再灌注模型,假手术组仅游离肠系膜上动脉,不夹闭。然后采用HE染色观察肠黏膜变化,TUNEL法检测细胞凋亡,Western blot和RT-PCR检测GRP78表达。结果:缺血再灌注后,肠黏膜损伤程度及细胞凋亡指数随再灌注时间延长而增加,于再灌注3 h达峰值(与其他组各组比较均P<0.001);再灌注后,GRP78的表达明显增加,于1 h达第1个小高峰(与0 h组和3 h组比较P<0.05),但随再灌注时间的延长,表达量逐步减少,再灌注12 h后开始回升(与6 h组比较P<0.004),于24 h达峰值(与其他各组比较均P<0.05),72 h降至对照组水平(与假手术对照组比较P>0.069)。结论:GRP78在大鼠肠缺血再灌注过程中表达变化,可能与其对肠IIRI保护机制有关。

GRP78 inhibits macrophage adhesion via SR-A

Class A scavenger receptor （SR-A） plays an important role in macrophage adhesion. However, the underlying mechanism remains unclear. We previously found that 78 kDa glucose-regulated protein （GRP78） inhibited SR- A-mediated ligand internalization into macrophage by binding to SR-A. The aim of the study was to investigate whether GRP78 could regulate SR-A-mediated cell adhesion. We demonstrated that GRP78 bound directly to SR-A by fluorescence resonance energy transfer （FRET） assay. Overexpression of GRP78 inhibited macrophage adhesion via SR-A. These results suggest that GRP78 may act as an inhibitor of macrophage adhesion via SR-A.

A new polymorphism in the GRP78 is not associated with HBV invasion

AIM:To examine the association between -86 bp(T>A) in the glucose-regulated protein 78 gene(GRP78) and hepatitis B virus(HBV) invasion.METHODS:DNA was genotyped for the single-nucleotide polymorphism by polymerase chain reaction followed by sequencing in a sample of 382 unrelated HBV carriers and a total of 350 sex-and age-matched healthy controls.Serological markers for HBV infection were determined by enzyme-linked immunosorbent as-say kits or clinical chemistry testing.RESULTS:The distributions of allelotype and genotype in cases were not significantly different from those in controls.In addition,our fi ndings suggested that neither alanine aminotransferase/hepatitis B e antigen nor HBV-DNA were associated with the allele/genotype variation in HBV infected individuals.CONCLUSION:-86 bp T>A polymorphism in GRP78 gene is not related to the clinical risk and acute exacerbation of HBV invasion.

Valproate reduces retinal ganglion cell apoptosis in rats after optic nerve crush

The retinal ganglion cells of the optic nerve have a limited capacity for self-repair after injury.Valproate is a histone deacetylase inhibitor and multitarget drug,which has been demonstrated to protect retinal neurons.In this study,we established rat models of optic nerve-crush injury and injected valproate into the vitreous cavity immediately after modeling.We evaluated changes in the ultrastructure morphology of the endoplasmic reticulum of retinal ganglion cells over time via transmission electron microscope.Immunohistochemistry and western blot assay revealed that valproate upregulated the expression of the endoplasmic reticulum stress marker glucose-regulated protein 78 and downregulated the expression of transcription factor C/EBP homologous protein,phosphorylated eukaryotic translation initiation factor 2α,and caspase-12 in the endoplasmic reticulum of retinal ganglion cells.These findings suggest that valproate reduces apoptosis of retinal ganglion cells in the rat after optic nerve-crush injury by attenuating phosphorylated eukaryotic translation initiation factor 2α-C/EBP homologous protein signaling and caspase-12 activation during endoplasmic reticulum stress.These findings represent a newly discovered mechanism that regulates how valproate protects neurons.

Rational design of a turn-on fluorescent probe for visualization of GRP78 protein in tumor models

Fluorescence image for accurate tumor label still faces challenges in cancer detection and diagnostics.Emerging evidence is indicating that glucose-regulated protein 78(GRP78), a stress-inducible protein chaperone, is a great potential biomarker and therapeutic target for cancer. However, currently available probe for image tumor based on GRP78 has not been reported, owning to no obvious strategy in probe design towards this protein. In this paper, a hairpin-shaped peptidyl probe(pep FAM) conjugated with a 5-FAM fluorophore and a dabcyl quencher at both ends was developed, respectively. The probe was designed by performing a traditional fluorescence resonance energy transfer mechanism and employing a GRP78 specifically-binding peptide. Furthermore, the probe was used to specifically image cancer cells,and accurately image xenograft tumors in mice models. The novel fluorescent probe is expected to be a useful tool for the diagnostics of cancer.

二甲双胍对人口腔癌KB细胞增殖及凋亡的影响

目的研究二甲双胍(Metformin)对人口腔癌KB细胞增殖及凋亡的影响,以期为口腔癌的治疗开辟新的路径。方法 MTT法检测不同浓度(1.25、2.5、5、10、20 mmol/L)二甲双胍处理口腔癌KB细胞24、48、72 h后对细胞增殖的影响;分别用0.25、0.5、1 mmol/L的二甲双胍处理KB细胞,8 d后观察其对集落克隆形成的影响;5 mmol/L二甲双胍处理细胞24 h,线粒体膜电位检测试剂盒(JC-1)检测线粒体膜电位的变化;PI单染检测二甲双胍对KB细胞凋亡的影响;Western blot检测二甲双胍(5 mmol/L)处理KB细胞不同时间(0、6、16、24 h)GRP78以及caspase-3的表达。结果二甲双胍处理细胞后,对KB细胞的增殖有明显的抑制作用,并且呈药物浓度和时间依赖性。5 mmol/L的二甲双胍处理KB细胞24、48、72 h的存活率为68.0%、36.9%、14.5%,但24 h细胞凋亡率仅为11.99%,将浓度加大后凋亡率为24.11%,高于对照组;二甲双胍抑制KB细胞集落克隆的形成;JC-1荧光检测,红绿荧光的相对比例降低,提示膜电位下降;二甲双胍刺激口腔癌KB细胞GRP78的表达先上调后有减弱趋势,并且能诱导Caspase-3的激活。结论二甲双胍能显著抑制KB细胞的增殖并且诱导细胞凋亡,其机制与线粒体凋亡途径的激活以及过度的内质网应激有关。

黄芪注射液联合葛根素注射液对糖尿病肾病KKA^y小鼠78kD-葡萄糖调节蛋白的影响

目的观察黄芪注射液联合葛根素注射液对糖尿病肾病KKAy小鼠78k D-葡萄糖调节蛋白(GRP78)表达的影响,为中医药治疗糖尿病肾病提供实验依据。方法雄性KKAy小鼠饲养至12周龄时随机分为模型组和黄芪注射液联合葛根素注射液治疗组;同龄雄性C57BL/6J小鼠作为正常对照组。观察小鼠日常状态,并于16周龄处死小鼠,取血清检测空腹血糖、尿素、肌酐、甘油三酯、总胆固醇,并取肾脏观察肾组织病理形态学变化,免疫组织化学法检测小鼠肾组织中GRP78的表达。结果模型组小鼠空腹血糖、尿素、肌酐、甘油三酯、总胆固醇较对照组明显升高(P<0.01);治疗组小鼠空腹血糖、尿素、肌酐较模型组降低(P<0.05或P<0.01)。形态学观察可见模型组小鼠肾小管上皮细胞胞浆出现空泡;经治疗后,肾小球、肾小管结构完整,病变不明显。免疫组化显示治疗组GRP78表达较模型组明显减少(P<0.01)。结论黄芪注射液联合葛根素注射液可在一定程度上抑制KKAy小鼠肾组织中GRP78表达,减轻内质网应激,保护2型糖尿病KKAy小鼠的肾功能。

葡萄糖调节蛋白78kD和热休克蛋白20在左半及右半结肠癌差异表达的初步研究

目的分析左半结肠癌与右半结肠癌肿瘤组织中差异蛋白表达情况。方法收集人左半结肠癌和右半结肠癌组织标本各7例．提取组织蛋白并进行二维凝胶电泳、质谱分析及生物信息学分离．鉴定二者中差异表达蛋白质。应用免疫组织化学sP法检测葡萄糖调节蛋白78kD（GRP78）和热休克蛋白20（HSP20）在50例左半和50例右半结肠癌组织中的表达情况。结果筛选并成功鉴定出左半和右半结肠癌中16种差异表达蛋白质：与右半结肠癌比较，左半结肠癌10种蛋白表达上调，6种蛋白表达下调，其中GRP78在左半结肠癌中表达上调，HSP20在左半结肠癌中表达下调。免疫组织化学检测示．GRP78在左半和右半结肠癌组织的阳性表达率分别为78％（39／50）和56％（28／50），差异有统计学意义（P〈0．05）；HSP20在左半和右半结肠癌的阳性表达率分别为34％（17／50）和72％（36／50），差异亦有统计学意义（P〈0．05）。GRP78表达与肿瘤分化程度、浸润层次、TNM分期、有无淋巴结转移以及有无肝转移有关（P〈0．05），而HSP20的表达与肿瘤大体形态、TNM分期以及有无淋巴结转移有关（P〈0．05）。结论左半结肠癌和右半结肠癌的蛋白质组存在蒡异．这些可能是左半与右半结肠癌生物学行为存在差异的原因。

人参皂苷Rb1调控内质网应激对脓毒症小鼠重要脏器的保护作用

目的观察人参皂苷Rb1对脓毒症小鼠重要脏器内质网应激的影响,探讨人参皂苷Rb1对脓毒症保护作用的分子机制。方法采用盲肠结扎并穿孔(CLP)法复制脓毒症模型。取60只成年(4~6周龄)C57BL/6雌性小鼠按随机数字表法分为正常组、假CLP组、人参皂苷组及CLP组,每组各15只。观察小鼠的一般状态,术后24 h处死小鼠,取心肌、肺组织行病理学检查。采用Western blotting法检测心肌和肺组织葡萄糖调节蛋白78(GRP78)及caspase-12蛋白的表达。结果与CLP组比较,人参皂苷组小鼠的一般状态明显改善。与CLP组比较,人参皂苷组肺泡组织结构相对清晰、完整,炎症细胞浸润减轻,肺泡大小均匀;人参皂苷组心肌组织的炎症细胞浸润较少,心肌横纹可见,坏死细胞少。与CLP组比较,人参皂苷组心肌及肺组织GRP78、caspase-12蛋白表达水平均显著减少,差异均有高度统计学意义(均P<0.01)。结论人参皂苷Rb1可以减轻脓毒症小鼠的感染严重程度,对小鼠心脏及肺组织的损伤有一定保护作用,其机制可能与人参皂苷Rb1抑制内质网应激的过表达有关。

ER stress and ER stress-induced apoptosis are activated in gastric SMCs in diabetic rats

AIM: To investigate the gastric muscle injury caused by endoplasmic reticulum (ER) stress in rats with diabetic gastroparesis.

GPER agonist G1 suppresses neuronal apoptosis mediated by endoplasmic reticulum stress after cerebral ischemia/reperfusion injury

Studies have confirmed a strong association between activation of the endoplasmic reticulum stress pathway and cerebral ischemia/reperfusion(I/R) injury.In this study,three key proteins in the endoplasmic reticulum stress pathway(glucose-regulated protein 78,caspase-12,and C/EBP homologous protein) were selected to examine the potential mechanism of endoplasmic reticulum stress in the neuroprotective effect of G protein-coupled estrogen receptor.Female Sprague-Dawley rats received ovariectomy(OVX),and then cerebral I/R rat models(OVX+ I/R) were established by middle cerebral artery occlusion.Immediately after I/R,rat models were injected with 100 μg/kg E2(OVX + I/R +E2),or 100 μg/kg G protein-coupled estrogen receptor agonist G1(OVX + I/R + G1) in the lateral ventricle.Longa scoring was used to detect neurobehavioral changes in each group.Infarct volumes were measured by 2,3,5-triphenyltetrazolium chloride staining.Morphological changes in neurons were observed by Nissl staining.Terminal dexynucleotidyl transferase-mediated nick end-labeling staining revealed that compared with the OVX + I/R group,neurological function was remarkably improved,infarct volume was reduced,number of normal Nissl bodies was dramatically increased,and number of apoptotic neurons in the hippocampus was decreased after E2 and G1 intervention.To detect the expression and distribution of endoplasmic reticulum stress-related proteins in the endoplasmic reticulum,caspase-12 distribution and expression were detected by immunofluorescence,and mRNA and protein levels of glucose-regulated protein 78,caspase-12,and C/EBP homologous protein were determined by polymerase chain reaction and western blot assay.The results showed that compared with the OVX+ I/R group,E2 and G1 treatment obviously decreased mRNA and protein expression levels of glucose-regulated protein 78,C/EBP homologous protein,and caspase-12.However,the G protein-coupled estrogen receptor antagonist G15(OVX + I/R + E2 + G15) could eliminate the effect of E2 on cerebral I/R injury.These results confirm that E2 and G protein-coupled estrogen receptor can inhibit the expression of endoplasmic reticulum stress-related proteins and neuronal apoptosis in the hippocampus,thereby improving dysfunction caused by cerebral I/R injury.Every experimental protocol was approved by the Institutional Ethics Review Board at the First Affiliated Hospital of Shihezi University School of Medicine,China(approval No.SHZ A2017-171) on February 27,2017.

Mitomycin C induces apoptosis in human epidural scar fibroblasts after surgical decompression for spinal cord injury

Numerous studies have shown that topical application of mitomycin C after surgical decompression effectively reduces scar adhesion. However, the underlying mechanisms remain unclear. In this study, we investigated the effect of mitomycin C on the proliferation and apoptosis of human epidural scar fibroblasts. Human epidural scar fibroblasts were treated with various concentrations of mitomycin C （1, 5, 10, 20, 40 μg/mL） for 12, 24 and 48 hours. Mitomycin C suppressed the growth of these cells in a dose- and time-dependent manner. Mitomycin C upregulated the expression levels of Fas, DR4, DR5, cleaved caspase-8/9, Bax, Bim and cleaved caspase-3 proteins, and it downregulated Bcl-2 and Bcl-xL expression. In addition, inhibitors of caspase-8 and caspase-9 （Z-IETD-FMK and Z-LEHD-FMK, respectively） did not fully inhibit mitomycin C-induced apoptosis. Furthermore, mitomycin C induced endoplasmic reticulum stress by increasing the expression of glucose-regulated protein 78, CAAT/enhancer-binding protein homologous protein （CHOP） and caspase 4 in a dose-dependent manner. Salubrinal significantly inhibited the mitomycin C-induced cell viability loss and apoptosis, and these effects were accompanied by a reduction in CHOP expression. Our results support the hypothesis that mitomycin C induces human epidural scar fibroblast apoptosis, at least in part, via the endoplasmic reticulum stress pathway.