Developmental changes in intercellular junctions and Kv channels in the intestine of piglets during the suckling and post-weaning periods

Background： The intestinal epithelium is an important barrier that depends on a complex mixture of proteins and these proteins comprise different intercellular junctions. The purpose of this study was to investigate the postnatal and developmental changes in morphology, intercellular junctions and voltage-gated potassium（Kv） channels in the intestine of piglets during the suckling and post-weaning periods.Results： Samples of the small intestine were obtained from 1-, 7-, 14-, and 21-d-old suckling piglets and piglets on d 1, 3, 5, and 7 after weaning at 14 d of age. The results showed that the percentage of proliferating cell nuclear antigen（PCNA）-positive cells and alkaline phosphatase（AKP） activity, as well as the abundances of E-cadherin,occludin, and Kv1.5 m RNA and claudin-1, claudin-3, and occludin protein in the jejunum were increased from d 1to d 21 during the suckling period（P 〈 0.05）. Weaning induced decreases in the percentage of PCNA-positive cells,AKP activity and the abundances of E-cadherin, occludin and zonula occludens（ZO）-1 m RNA or protein in the jejunum on d 1, 3 and 5 post-weaning（P 〈 0.05）. There were lower abundances of E-cadherin, occludin and ZO-1m RNA as well as claudin-1, claudin-3 and ZO-1 protein in the jejunum of weanling piglets than in 21-d-old suckling piglets（P 〈 0.05）. The abundances of E-cadherin, occludin, ZO-1 and integrin m RNA were positively related to the percentage of PCNA-positive cells.Conclusion： Weaning at 14 d of age induced damage to the intestinal morphology and barrier. While there was an adaptive restoration on d 7 post-weaning, the measured values did not return to the pre-weaning levels, which reflected the impairment of intercellular junctions and Kv channels.

Lactobacillus rhamnosus GR-1 attenuates foodborne Bacillus cereus-induced NLRP3 inflammasome activity in bovine mammary epithelial cells by protecting intercellular tight junctions

Background:Bacillus cereus is an important pathogen that causes human food poisoning,specifically diarrhea and vomiting.B.cereus can also induce mastitis in dairy cows and has a strong survival ability in milk,as it cannot be inactivated by high-temperature short-time pasteurization.Therefore,B.cereus can enter the market through pasteurized milk and other dairy products,imposing enormous hidden dangers on food safety and human health.Results:In this study,B.cereus 2101(BC)was isolated from milk samples of cows with mastitis.BC grew rapidly with strong hemolysis,making it difficult to prevent mastitis and ensure food security.MAC-T cells were treated with BC and/or Lactobacillus rhamnosus GR-1(LGR-1).Pretreatment with LGR-1 protected the integrity of tight junctions and the expression of zonula occludens-1(ZO-1)and occludin destroyed by BC.Furthermore,LGR-1 pretreatment reduced the expression of NOD-like receptor family member pyrin domain-containing protein 3(NLRP3),caspase recruitment and activation domain(ASC),Caspase-1 p20,gasdermin D(GSDMD)p30,inflammatory factors(interleukin(IL)-1βand IL-18),and cell death induced by BC.Moreover,LGR-1 pretreatment reduced NLRP3 inflammasome activity and increased expressions of ZO-1 and occludin induced by lipopolysaccharides(LPS)+ATP stimulation.MAC-T cells were transfected with NLRP3 si RNA or MCC950 and/or treated with BC and/or LGR-1.NLRP3-si RNA transfection and MCC950 attenuated BC-induced NLRP3 inflammasome activity.Expression of inflammatory cytokines and cell death suggested that the inflammatory pathway might play an important role in the induction of the NLRP3 inflammasome by BC and the protection of LGR-1.Conclusions:These results suggest that LGR-1 might be a probiotic alternative to antibiotics and could be administered to prevent mastitis in dairy cows,thus ensuring food security.

Altered Expression of Connexin-43 and Impaired Capacity of Gap Junctional Intercellular Communication in Prostate Cancer Cells

Connexin-43 (Cx43) expression in prostate cancer (PCa) cells and the potency of gap junctional intercellular communication (GJIC) in the cells were investigated, with an attempt to elu- cidate the reason why the so-called 'bystander effect' mediated by thymidine kinase (TK) suicide gene therapy on PCa cells is not of significance and to explore the role of GJIC in PCa carcinogenesis. mRNA and protein expression of Cx43 in a PCa cell line PC-3m was detected by re- verse-transcription polymerase chain reaction (RT-PCR) and strapt-avidin-biotin-enzyme complex (SABC) immunohistochemical staining, and inherent GJIC of PC-3m cells was assayed by scrape-loading and dye transfer (SLDT) assay. The expression of Cx43 in human normal and malig- nant prostate tissues was determined by SABC immunohistochemistry as well. It was found that Cx43 mRNA and protein expression in PC-3m cells was slightly reduced as compared with positive controls and the location of Cx43 protein was aberrant in cytoplasm rather than on membrane. As- sessment of paraffin sections demonstrated that the expression of Cx43 protein in PCa cells was ab- normally located and markedly diminished as compared with normal prostatic epithelial ones, dis- playing a negative correlation to the pathological grade (χ2=4.025, P<0.05). Additionally, capacity of inherent GJIC in PC-3m cells was disrupted, which was semi-quantified as (+) or (-). It was indi- cated that both down-regulated expression of Cx43 mRNA and aberrant location of Cx43 protein par- ticipated in the mechanisms leading to deficient GJIC in PC-3m cells. Lack of efficient GJIC is a molecular event, which may contribute not only to limited extent of 'bystander effect', but also to initiation and progression of prostatic neoplasm.

THE EFFECT OF ALL-TRANS RETINOIC ACID ON GAP JUNCTIONAL INTERCELLULARCOMMUNICATION AND CONNEXIN 43 GENE EXPRESSION IN GLIOMA CELLS

To illuminate the regulating effect of all trans retinoic acid (ATRA ) on gap junctional intercellular communication (GJIC) and connexin 43 (Cx43) ge ne expression in glioma cells, which is tissue and organ specific. Method. Rat C6 glioma cells were exposed to ATRA at a concentration of 1, 10, 10 0 μmol/L respectively, and the GJIC function of the cells was examined with scr ape loading dye transfer assay 24 hours, 48 hours and 72 hours after ATRA treat ment. The effect of ATRA on Cx43 gene expression was measured with semiquantitat ive reverse transcription polymerase chain reaction (RT PCR) 24 hours after ATR A exposure. Results. The GJIC function of C6 glioma cells was significantly increased by ATR A at each concentration applied. The dye passed 4 to 5 rows of cells from the sc raping edge in ATRA treated cells, but only 1 or 2 rows in the control. The augm ent effect was observed 24 hours after each concentration ATRA treatment, and la sted till 72 hours after treatment with 1μmol/L and 10μmol/L ATRA. Forty eigh t hours after exposed to 100μmol/L ATRA, the enhancement of GJIC was less obvi ous. There was no significant increase induced by ATRA on the transcription of C x43 gene, as demonstrated by semiquantitative RT PCR. Conclusion. ATRA turned out to be a potent enhancer on GJIC function in C6 gliom a cells, and the enhancement effect was most probable at post transcriptional l evel.

Effect of Apigenin on Gap Junctional Intercellular Communication in Human Tenon's Capsule Fibroblasts

Purpose:To investigate the effect of apigenin on gap junctional intercellular communication (GJIC) in human Tenon's capsule fibroblasts (HTFs) and its underlying mechanism. Methods:After a 48 h treatment of cultured HTFs with apigenin.(80 μmol/L),the GJIC was detected by a scrape-loading/dye transfer technique with Lucifer yellow dye and rhodamine (Rh) dextran. The coupling index represents a quantification of GJIC where a high coupling index is associated with a greater number of cells demonstrating cell-cell communication through gap junction channels.The changes in connexin 43 (Cx43) distribution and the expression of Cx43 at the protein and mRNA levels were statistically compared between the two groups by means of immunocytochemistry, western blotting,and real-time polymerase chain reaction (PCR). Results:The functioning of GJIC in the HTFs was significantly enhanced after 48 hours by apigenin treatment when compared with the control cells. In the apigenin group, the intercellular dye transfer grade was above 9, while this value was only grade 3-4 in the control group. The coupling index was significantly increased up to 9.205±0.3621 in the apigenin group,compared with 5.1775 ±0.3177 in the control group (F=279.581, P=0.000). The expression of Cx43 at the protein and mRNA levels was significantly up-regulated in the apigenin group compared with the control group. Conclusion:Apigenin can significantly enhance the function of GJIC in HTFs by up-regulating the expression of Cx43 at both the protein and mRNA levels,suggesting that the enhancement of GJIC in HTFs by apigenin probably acts as an important mechanism underlying the inhibitory effect of apigenin on HTF proliferation.

Up-Regulation of the Gap Junction Intercellular Communication by Tea Polyphenol in the Human Metastatie Lung Carcinoma Cell Line

Our previous study has proven that tea polyphenol has a role in lung neoplasms. The present communication was to investage the anti-proliferation effect of tea polyphenol on the PG cells, which was a high metastatic human lung carcinoma cell line, by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-diphenytetrazoliumromide (MTT) cell viability assay, and to study the change of intracellular calcium concentration, connexin43 (Cx43) expression, gap junctional intercellular communication (GJIC) and cell cycle distribution after the tea polyphenol treatment by laser scanning confocal microscopy and flow cytometry. The results showed that 1) tea polyphenol could kill the PG cells in a dose-depent manner via inhibiting the PG cell proliferation and blocking the PG cell cycle progression staying in G0/G1 phase and not transfering in S and G2/M phases to reduce the PG cell proliferation index;2) the increases of intracellular calcium concentration, GJIC and Cx43 expression were related with the tea polyphenol doses. The data suggested that tea polyphenol could inhibit the growth of PG cells, which mechanism was associated with the up-regulation of GJIC.

EFFECTS OF LIMONENE,SALVIA MILTIORRHIZA AND TURMERIC DERIVATIVES ON H-RAS ONCOGENE EXPRESSION AND GAP JUNCTION INTERCELLULAR COMMUNICATION IN HUMAN SOLID TUMOR CELL LINES

Objective: To study gap junction intercellular communication (GJIC), H ras oncogene expression and ras oncogene product (P 21 ras protein) expression in four human solid tumor cell lines, W1-38,CACO 2,A549 and PaCa, and the effects of four compounds, Salvia miltiorrhiza derivative (SMD), d Limonene, Turmeric derivative I (TD I) and Turmeric derivative II (TD II), on them. Methods: The abilities of the four solid tumor cell lines to transfer dye to adjacent cells were examined by the scrape loading/dye transfer technique, and the H ras oncogene expression by Northern blotting and P 21 ras protein expression by Western blotting. Results: The results showed the loss of intercellular coupling in PaCa cells, slight GJIC in A549 and CACO 2 cells, and a good GJIC in W1-38 cells. The four compounds could improve the GJIC of PaCa to different extents. The amount of total and membrane associated P 21 ras in PaCa cells were decreased after treatment with SMD, d Limonene and TD I (2.5 μg/ml) for 48 h. Concomitantly, the growth of PaCa cells decreased in soft agar and had enhanced GJIC. The relative potency was found to be:d Limonene>SMD >TD I=TD II. There was no significant effect of the four compounds on H ras oncogene expression. Conclusion: It was suggested that there was an excellent correlation between loss of Lucifer Yellow dye transfer and ras gene mutation rate in the four solid tumor cell lines (ras gene mutation rate inversely correlated with average cell number coupled, r=0.98) i.e., the high ras gene mutation was closely correlated with loss of GJIC in these malignant human tumor cells; The antitumor effect of the monoterpene d Limonene and the phenol compound, SMD, might be related to inhibition of P 21 ras membrane association and enhancement of GJIC, whilst that of the others may be by a different mechanism; The inhibition of P 21 ras membrane association was directly related to the enhancement of gap junction intercellular com munication.

STUDIES ON THE GAP JUNCTIONAL INTERCELLULARCOMMUNICATION OF HUMAN NASOPHARYNGEALCARCINOMA CELLS AND THE EFFECT OF RII

Human nasopharyngeal carcinoma(NPC) cell line,CNE-2Z, and its clones(L2, H2, L4) with various invasive and metastatic potentials were examined for their gap junctions(GJ), gap junctional intercellular communication(GJIC) and the concentration of cytosolic free calcium(Ca2+). Only a few intermediate junction(IJ)but no GJ structures were observed under electron microscope(EM). CNE-2Z cells showed marked JGIC,while its variants lacked this function using the scraploading dye-transfer technique(SLDT). There was lower concentration of[Ca2+]. in L2 cells(a variant with high invasive and metastatic Potential) compared to that in H2 and L4 cells(variants with medium and low invasive and metastatic Potentials, respectively). These data suggested that high invasive and metastatic potentials might be correlated with the levcl of[Ca2+]i in NPC cells.The effect of RII(4-hydroxycarbophenyl retinamide) on NPC cells also investigated, After 3-7 d of RII(10-5 M) treatment, there was no change in the number of gap junctions and other kind of intercellular junctions in NPC cells observed under EM. The JGIC of CNE-2Z weaked and then disappeared finally with prolonging of RII treatment. However. there was no influence on its variants. The level of[Ca2+], in NPC cells apparently fell after 6 h of RII treatment, and rose to original level with persisting of RII treatment. Whether the fluctuating of[Ca2+]i level is related to the inhibitory effect of RII treatment on growth and invasion of NPC cells needs to be further studied.

Changes of gap junctional intercellular communication in detrusor instability

Objective: To demonstrate the functional changes of gap junctional mediation of intercellular communication in detrusor instability (DI) and its mechanisms. Methods: The function of gap junctional intercellular communication in the cultured bladder detrusor cells was detected by fluorescence redistribution after photobleaching. Results: At the fourth minute after bleaching, the mean fluorescences recovery rates of DI group bladder detrusor cells were (35 791±0 836)%, that of control group (8 645±0 673)%. The mean fluorescence recovery rates of DI group were significantly higher than those of control group ( P <0 01). Conclusion: It shows that the increase of intercellular excitatory communication is one of the important reasons of pathogenesis of DI.

Mechanism of changes in gap junctional intercellular communication in myocardial cells after burns

Objective: To explore the pathophysiological mechanism of the changes in gap junctionalintercellular communication (GJIC) in the myocardial cells after burns. Methods: After the myocardial cellswere cultured and injured with hypoxia and burn serum, the GJIC in the cells was detected with scrapeloading and dye transfer. Meanwhile, the viability, cytosolic free Ca2+ concentration and Ca2+ influx of themyocardial cells were determined. Results: The cytosolic free Ca2+ concentration and the cellulartransmembrane Ca2+ influx were significantly increased but the viability of the cells markedly decreased afterthe injury. The LY fluorescence reached 4 rows of cells from the scrape line in the normal myocardial cells.The GJIC was blocked at the first hour after hypoxia or hypoxia and burn serum injury. The LY fluorescencewas limited to the primary loads cells at the sixth hour after hypoxia and the third hour after hypoxia andburn serum injury. Conclusion: The function of GJIC in the myocardial cells is to maintain high ordersynchronous contraction of the myocardium. After burns, the runaway calcium homeostasis and impairmentof GJIC function would be accused to be the pathological basis for myocardial heterogeneous behavior.

过劳诱导小鼠血管内皮屏障功能障碍

目的研究过劳对小鼠血管内皮屏障功能的影响。方法将30只KM小鼠随机分为3组(n=10):对照(CON)组、过劳2周(W2)组、过劳4周(W4)组。W2组和W4组采用水中站立+束缚实验分别连续造模2周和4周,观察小鼠一般情况。造模结束后,每组选取4只小鼠腹腔注射Evans蓝染料,检测血管通透性。另6只小鼠采取ELISA法检测血清IL-1β含量,获取动脉组织行切片观察,RT-qPCR法检测内皮细胞间紧密连接中occludin、claudin-5、ZO-1、JAM-A和黏附连接中VE-cadherin的mRNA表达水平;免疫荧光法检测内皮细胞间连接复合物中claudin-5、ZO-1、VE-cadherin和血管内皮糖萼中Syndecan-1的蛋白表达情况。结果与CON组相比,W2和W4组小鼠体质量增长缓慢,毛发脱落,活动减少。与CON组相比,W4组血管通透性明显增加。与CON组相比,W2和W4组血清IL-1β含量增加(P<0.05)。与CON组相比,W2组内皮细胞肿胀、脱落,内膜粗糙不规则,W4组出现内膜断裂现象。与CON组相比,W2组动脉组织中occludin、claudin-5、ZO-1、JAM-A的mRNA表达量增加,W4表达均降低(P<0.05);W2和W4组VE-cadherin的mRNA表达量下降(P<0.05)。与CON组相比,W4组claudin-5、ZO-1、VEcadherin和Syndecan-1蛋白表达减少(P<0.05)。结论过劳随时间的延长可对动脉内皮细胞间连接复合物以及内皮糖萼造成损伤,破坏其屏障功能,导致血管通透性增加。

六味地黄丸通过干预缝隙连接通讯功能调控树突状细胞抗原交叉提呈能力研究

【目的】探讨六味地黄丸是否通过提高缝隙连接通讯功能(GJIC)增强树突状细胞(DC)抗原交叉提呈能力,并对其机制进行相关探索。【方法】采用Western Blot实验、免疫荧光法观察六味地黄丸含药血清对黑色素瘤细胞(B16)缝隙连接蛋白43(Cx43)表达及膜定位的影响;采用钙黄绿素(Ca-AM)/DiI荧光示踪实验观察六味地黄丸含药血清对B16细胞GJIC功能的影响;采用流式细胞术观察GJIC在六味地黄丸含药血清增强DC抗原提呈能力中的作用;采用碘化丙啶(PI)/Hoechst染色实验观察CD8+T淋巴细胞的免疫杀伤效果。【结果】Western Blot及免疫荧光实验结果显示,六味地黄丸含药血清上调Cx43表达;荧光示踪实验证明,六味地黄丸含药血清显著增强B16细胞GJIC功能;流式细胞术分析表明,六味地黄丸含药血清增强DC抗原提呈能力;PI/Hoechst染色结果显示,六味地黄丸含药血清干预B16-OVA后CD8+T细胞的免疫杀伤效果更加显著。【结论】六味地黄丸通过上调黑色素瘤细胞Cx43表达,改善GJIC功能,进而增强DC的交叉提呈能力,从而激活更强的CD8+T细胞免疫杀伤反应。

Differences between the gap junctional communication function of fibroblasts derived from pathological scars and normal skin

Objective: To define the mechanisms underlying the keloid formation. Methods: The gap junctional intercellu- lar commumication (GJIC) of fibroblasts derived from pathological scars and noed skin was investigated. Six Samples of hyperplastic scars, keloids and normal skin were obtained. Fibroblasts from these samples were cultured in ho and vended by type Ⅰ collagen, and the GJIC among the fibroblasts was investigated by adherent cell analysis with soning interactive laser coytometer(ACAS 570) for fibroblasts culturing. Results: The fibroblasts from normal skin showed nounal GJIC, which are depressed between fibroblasts from hyperplastic scare and was completely blocked in fibroblasts from the keloids. Conclusion: The blockade of interoellular communication may play an important role in the pathogenesis of excessive and invasive growth of fibroblasts derived from the keloids.

Basic Investigations EXPRESSION OF GAP JUNCTION PROTEIN Cx43 IN CULTURED HUMAN NORMAL AND MALIGNANT LUNG CELLS

Gap junctional intercellular communicationexchange of small molecules and ions between contiguous cells through membranous gap junctional channelsis essential for growth control and tissue homecotasis. This work concerns the functional expression of gap junction protein connexin 43 (Cx43) in normal human lung cells and the changes in lung carcinoma cells. By. using Northern blot hybridization analysis and Cx43 immunocytochemical methods, it was otherved that cultured normal human embryonic lung cells expressed a high level of Cx43 in both mRNA and protein levels.The Cx43 immunofluorescence was localized at cell membrane regions corresponding to the location of gap junctions. These normal lung cells were competent of intercellular communication function as detected by Lucifer yellow dye transfer. In contrast to normal celis, Cx43 mRNA and protein was not detectable in the carcinoma PG cell line. These tumor cells were defective of intercellular communication function. These results demonstrate that Cx43 is expressed in normal cultured human embryonic lung cells but not in lung tumor cells. The lack of intercellular communication in the lung tumor cell line correlates with dysfunctional intercellular communication. The suggestive role of Cx as a tumor suppersor gene is discussed.

人参多糖对肠上皮屏障的增强作用及其机制

目的观察人参多糖对大鼠小肠上皮细胞(IEC-6)渗透性、黏附连接蛋白表达及细胞钙离子(Ca^(2+))水平的影响,探讨益气健脾中药人参肠黏膜保护作用机制。方法设置不同实验条件[正常含钙培养、含钙培养+二氟甲基鸟氨酸(DFMO)、无钙培养]以观察人参多糖的作用;Transwell小室酚红透过法检测细胞间渗透性;Western blotting法检测黏附连接蛋白(E-cadherin、α-catenin和β-catenin)表达;激光共聚焦显微镜观察细胞Ca^(2+)水平。结果①正常含钙培养时,人参多糖(40、80、160 mg·L^(-1),下同)能降低细胞间渗透性、提高E-cadherin、α-catenin和β-catenin表达及细胞Ca^(2+)水平(P<0.05或P<0.01);②含钙培养+DFMO负荷时,细胞间渗透性增加、E-cadherin和α-catenin表达及Ca^(2+)水平降低(P<0.05或P<0.01),人参多糖可改善DFMO所致的细胞间渗透性增加、E-cadherin和α-catenin表达及Ca^(2+)水平降低(P<0.05或P<0.01);③无钙培养可致细胞间渗透性增加及E-cadherin、α-catenin和β-catenin表达降低(P<0.05或P<0.01),人参多糖可改善无钙培养所致的细胞间渗透性增加及E-cadherin和α-catenin表达下降(P<0.05或P<0.01)。结论人参多糖具有增强肠上皮屏障的作用,其机制与提高细胞Ca^(2+)水平及黏附连接蛋白表达有关。

Th9细胞及IL-9在嗜酸细胞性胃肠炎发病机制中的作用

目的儿童嗜酸细胞性胃肠炎(EG)的发病机制尚不明确,且Th9细胞在EG中的作用机制研究甚少。文中旨在检测EG患儿结肠黏膜中Th9细胞、IL-9及各种细胞间连接蛋白的表达水平,探讨Th9细胞在儿童EG发病中的可能作用。方法选取2017年9月至2019年10月在南京医科大学附属儿童医院消化科住院且诊断为EG的20例患儿为EG组。选取同期以腹痛、腹泻、便血、呕吐等胃肠道症状为主诉,排除EG诊断的20例患儿为对照组。两组患儿均进行血常规、血清总IgE、血清免疫球蛋白及补体测定、影像学和结肠镜检查,并留取结肠黏膜组织,用免疫荧光法标记结肠黏膜组织中的Th9细胞,用RT-PCR法测定结肠黏膜组织中IL-9、PU.1、STAT3、S100A8、S100A9和细胞间连接蛋白(包括Claudin-2、Claudin-3、Occludin、E-钙粘蛋白和β-连环蛋白)的mRNA表达。结果EG组患儿外周血嗜酸性粒细胞绝对值、血清总IgE水平较对照组显著升高(P<0.05),结肠黏膜组织中Th9细胞较对照组明显增多(P<0.05)。EG组患儿结肠黏膜组织中IL-9、PU.1、STAT3、Claudin-2和S100A8的mRNA表达量显著高于对照组(P<0.05),Claudin-3、Occludin、E-钙粘蛋白和β-连环蛋白的mRNA表达量显著低于对照组(P<0.05)。结论EG儿童结肠黏膜中Th9细胞增多,IL-9表达增高,可能影响细胞间连接蛋白的表达,使肠黏膜通透性增加,参与了EG的发病。

Connexin 43-modified bone marrow stromal cells reverse the imatinib resistance of K562 cells via Ca^(2+)-dependent gap junction intercellular communication

Background: Imatinib mesylate (IM) resistance is an emerging problem for chronic myeloid leukemia (CML). Previous studies found that connexin 43 (Cx43) deficiency in the hematopoietic microenvironment (HM) protects minimal residual disease (MRD), but the mechanism remains unknown. Methods: Immunohistochemistry assays were employed to compare the expression of Cx43 and hypoxia-inducible factor 1α (HIF-1α) in bone marrow (BM) biopsies of CML patients and healthy donors. A coculture system of K562 cells and several Cx43-modified bone marrow stromal cells (BMSCs) was established under IM treatment. Proliferation, cell cycle, apoptosis, and other indicators of K562 cells in different groups were detected to investigate the function and possible mechanism of Cx43. We assessed the Ca^(2+)-related pathway by Western blotting. Tumor-bearing models were also established to validate the causal role of Cx43 in reversing IM resistance. Results: Low levels of Cx43 in BMs were observed in CML patients, and Cx43 expression was negatively correlated with HIF-1α. We also observed that K562 cells cocultured with BMSCs transfected with adenovirus-short hairpin RNA of Cx43 (BMSCs-shCx43) had a lower apoptosis rate and that their cell cycle was blocked in G0/G1 phase, while the result was the opposite in the Cx43-overexpression setting. Cx43 mediates gap junction intercellular communication (GJIC) through direct contact, and Ca ^(2+ )is the key factor mediating the downstream apoptotic pathway. In animal experiments, mice bearing K562, and BMSCs-Cx43 had the smallest tumor volume and spleen, which was consistent with the in vitro experiments. Conclusions: Cx43 deficiency exists in CML patients, promoting the generation of MRD and inducing drug resistance. Enhancing Cx43 expression and GJIC function in the HM may be a novel strategy to reverse drug resistance and promote IM efficacy.

低温缺氧/复氧后大鼠心肌成纤维细胞对心肌H9c2细胞间通讯的影响

目的观察低温缺氧/复氧(hypothermia hypoxia/reoxygen,H/R)后大鼠心肌成纤维细胞(rat cardiac fibroblasts,RCFs)对心肌H9c2细胞间通讯的影响并探讨其可能机制。方法将RCFs细胞与H9c2细胞以2:1数量比Transwell共培养后随机分为6组。其中T+AngⅡ组及H/R⁃T+AngⅡ组加入1.5 nmol/L AngⅡ,T+ARB组及H/R⁃T+ARB组加入1 nmol/L缬沙坦。T组、T+AngⅡ组及T+ARB组进行正常培养,H/R⁃T组、H/R⁃T+AngⅡ及H/R⁃T+ARB组进行H/R处理。检测各组培养液中AngⅡ含量;H9c2细胞Cx43、ERK1/2表达量及磷酸化及细胞间通讯情况。结果与T组相比,H/R⁃T组及T+AngⅡ组H9c2细胞ERK1/2、Cx43表达及磷酸化水平降低(P<0.05),细胞间通讯减弱(P<0.05);T+ARB组H9c2细胞ERK1/2、Cx43表达及磷酸化水平增高(P<0.05),细胞间通讯增强(P<0.05)。与H/R⁃T组相比,H/R⁃T+AngⅡ组H9c2细胞ERK1/2、Cx43表达及磷酸化水平降低(P<0.05),细胞间通讯减弱(P<0.05);H/R⁃T+ARB组H9c2细胞ERK1/2、Cx43表达及磷酸化水平增加(P<0.05),细胞间通讯增强(P<0.05)。结论H/R处理后,RCFs细胞分泌增多的AngⅡ可能通过抑制H9c2细胞MAPK/ERK通路下调Cx43表达,导致H9c2细胞间通讯减弱。

幽门螺杆菌感染与胃上皮细胞间隙连接功能的体外研究

目的 探讨幽门螺杆菌(H.pylon,Hp)对胃上皮细胞间隙连接通讯(GJIC)功能的影响及其发病机制。方法 应用Hp(包括Cag A+和Cag A-株)全菌和超声粉碎上清分别作用胃上皮细胞株SGC- 790 1。采用激光扫描共焦显微镜(L SCM,L eica TCS SP)以荧光光漂白后再恢复(FRAP)技术测定SGC- 790 1细胞GJIC功能(以荧光传递速率K表示,×10 - 3/ s)。结果 Cag A+和Cag A- Hp株均下调SGC- 790 1细胞GJIC功能(Cag A+ :F=5 7.98;Ca-g A- :F=2 9.5 9,P<0 .0 1) ;且Cag A+ 与Cag A- Hp相比前者更显著下调胃上皮细胞GJIC功能(全菌:t=13.86 ,P<0 .0 1;超声粉碎上清:t=11.87,P<0 .0 1)。结论 Cag A+ 比Cag A- Hp显著抑制胃上皮细胞的GJIC功能,提示其在胃癌发生中起重要作用。

内毒素、烫伤血清对培养的大鼠心脏微血管内皮细胞间连接的影响

目的：探讨内毒素、烫伤血清对培养的心脏微血管内皮细胞（ＣＭＥＣ）间连接成分ＶＥ－钙粘附分子表达的影响，研究内毒素对严重烧伤后内皮细胞的损伤机制。方法：①ＣＭＥＣ的分离培养；②烫伤血清和内毒素刺激培养的ＣＭＥＣ后ＥＬＩＳＡ测定内皮细胞间连接成分ＶＥ－钙粘附分子的表达。结果：ＣＭＥＣ经２０％的烫伤血清刺激后，６ｈ开始ＶＥ－钙粘附分子的表达即有明显减少，是正常对照组的６５％，到２４ｈ仍在低的水平（Ｐ＜０．０１）；经内毒素（２ｍｇ／Ｌ）刺激，从１ｈ开始即有显著降低，是对照组的８０％，６ｈ降低到最低点，是对照组的５６％，后仍在低的水平（Ｐ＜０．０１）。不同浓度的内毒素（０．５、１．０、１．５和２．０ｍｇ／Ｌ）对培养的ＣＭＥＣ进行刺激，作用１２ｈ后，与正常对照组相比差异显著（Ｐ＜０．０５和Ｐ＜０．０１），分别为对照组的８８％、８３％、８０％和４７％，且２．０ｍｇ／Ｌ刺激组有更明显的降低；相同浓度的内毒素（均为２．０ｍｇ／Ｌ）刺激，有血清和不含血清组差异不明显（Ｐ＞０．０５）。结论：烫伤血清和内毒素可以影响内皮细胞中ＶＥ－钙粘附分子的表达，内毒素的影响有剂量的依赖关系，有无血清的存在对ＶＥ－钙粘附分子表达的影响差异不明显?