Efficient generation of functional hepatocytelike cells from mouse liver progenitor cells via indirect co-culture with immortalized human hepatic stellate cells

BACKGROUND： Differentiation of liver progenitor cells（LPCs） to functional hepatocytes holds great potential to develop new strategies for hepatocyte transplantation and the screening of drug-induced cytotoxicity. However, reports on the efficient and convenient hepatic differentiation of LPCs to hepatocytes are few. The present study aims to investigate the possibility of generating functional hepatocytes from LPCs in an indirect co-culture system.METHODS： Mouse LPCs were co-cultured in Transwell plates with an immortalized human hepatic stellate cell line（HSCLi） we previously established. The morphology, expression of hepatic markers, and functions of mouse LPC-derived cells were monitored and compared with those of conventionally cultured LPCs. RESULTS： Co-culturing with HSC-Li cells induced differentiation of mouse LPCs into functional hepatocyte-like cells. The differentiated cells were morphologically transformed into hepatocyte-like cells 3 days after co-culture initiation. In addition, the differentiated cells expressed liver-specific genes and possessed hepatic functions, including glycogen storage, lowdensity lipoprotein uptake, albumin secretion, urea synthesis, and cytochrome P450 1A2 enzymatic activity.CONCLUSIONS： Our method, which employs indirect co-culture with HSC-Li cells, can efficiently induce the differentiation of LPCs into functional hepatocytes. This finding suggests that this co-culture system can be a useful method for the efficient generation of functional hepatocytes from LPCs.

Regeneration and activation of liver progenitor cells in liver cirrhosis

Cirrhosis is characterized as the progress of regenerative nodules surrounded by fibrous bands in response to chronic hepatic injury and causes portal hypertension and end-stage hepatic disease.Following liver injury,liver progenitor cells(LPCs)can be activated and differentiate into hepatocytes in order to awaken liver regeneration and reach homeosta-sis.Recent research has uncovered some new sources of LPCs.Here,we update the mecha-nisms of LPCs-mediated liver regeneration in cirrhosis by introducing the origin of LPCs and LPCs’niche with a discussion of the influence of LPC-related cells.This article analyzes the mechanism of regeneration and activation of LPCs in cirrhosis in recent years aiming to provide help for clinical application.

Stages based molecular mechanisms for generating cholangiocytes from liver stem/progenitor cells

Except for the most organized mature hepatocytes,liver stem/progenitor cells(LSPCs)can differentiate into many other types of cells in the liver including cholangiocytes.In addition,LSPCs are demonstrated to be able to give birth to other kinds of extra-hepatic cell types such as insulin-producing cells.Even more,under some bad conditions,these LSPCs could generate liver cancer stem like cells(LCSCs)through malignant transformation.In this review,we mainly concentrate on the molecular mechanisms for controlling cell fates of LSPCs,especially differentiation of cholangiocytes,insulin-producing cells and LCSCs.First of all,to certificate the cell fates of LSPCs,the following three features need to be taken into account to perform accurate phenotyping:(1)morphological properties;(2)specific markers;and(3)functional assessment including in vivo transplantation.Secondly,to promote LSPCs differentiation,systematical attention should be paid to inductive materials(such as growth factors and chemical stimulators),progressive materials including intracellular and extracellular signaling pathways,and implementary materials(such as liver enriched transcriptive factors).Accordingly,some recommendations were proposed to standardize,optimize,and enrich the effective production of cholangiocyte-like cells out of LSPCs.At the end,the potential regulating mechanisms for generation of cholangiocytes by LSPCs were carefully analyzed.The differentiation of LSPCs is a gradually progressing process,which consists of three main steps:initiation,progression and accomplishment.It’s the unbalanced distribution of affecting materials in each step decides the cell fates of LSPCs.

Transplantation of bone marrow-derived endothelial progenitor cells and hepatocyte stem cells from liver fibrosis rats ameliorates liver fibrosis

AIM To explore the effectiveness for treating liver fibrosisby combined transplantation of bone marrow-derived endothelial progenitor cells(BM-EPCs) and bone marrow-derived hepatocyte stem cells(BDHSCs) from the liver fibrosis environment.METHODS The liver fibrosis rat models were induced with carbon tetrachloride injections for 6 wk. BM-EPCs from rats with liver fibrosis were obtained by different rates of adherence and culture induction. BDHSCs from rats with liver fibrosis were isolated by magnetic bead cell sorting. Tracing analysis was conducted by labeling EPCs with PKH26 in vitro to show EPC location in the liver. Finally, BM-EPCs and/or BDHSCs transplantation into rats with liver fibrosis were performed to evaluate the effectiveness of BM-EPCs and/or BDHSCs on liver fibrosis.RESULTS Normal functional BM-EPCs from liver fibrosis rats were successfully obtained. The co-expression level of CD133 and VEGFR2 was 63.9% ± 2.15%. Transplanted BM-EPCs were located primarily in/near hepatic sinusoids. The combined transplantation of BM-EPCs and BDHSCs promoted hepatic neovascularization, liver regeneration and liver function, and decreased collagen formation and liver fibrosis degree. The VEGF levels were increased in the BM-EPCs(707.10 ± 54.32) and BM-EPCs/BDHSCs group(615.42 ± 42.96), compared with those in the model group and BDHSCs group(P < 0.05). Combination of BM-EPCs/BDHSCs transplantation induced maximal up-regulation of PCNA protein and HGF m RNA levels. The levels of alanine aminotransferase(AST), aspartate aminotransferase, total bilirubin(TBIL), prothrombin time(PT) and activated partial thromboplastin time in the BMEPCs/BDHSCs group were significantly improved, to be equivalent to normal levels(P > 0.05) compared with those in the BDHSC(AST, TBIL and PT, P < 0.05) and BM-EPCs(TBIL and PT, P < 0.05) groups. Transplantation of BM-EPCs/BDHSCs combination significantly reduced the degree of liver fibrosis(staging score of 1.75 ± 0.25 vs BDHSCs 2.88 ± 0.23 or BMEPCs 2.75 ± 0.16, P < 0.05).CONCLUSION The combined transplantation exhibited maximal therapeutic effect compared to that of transplantation of BM-EPCs or BDHSCs alone. Combined transplantation of autogenous BM-EPCs and BDHSCs may represent a promising strategy for the treatment of liver fibrosis, which would eventually prevent cirrhosis and liver cancer.

Human liver stem/progenitor cells decrease serum bilirubin in hyperbilirubinemic Gunn rat

AIM: To test the ability of adult-derived human liver stem/progenitor cells (ADHLSC) from large scale cultures to conjugate bilirubin in vitro and in bilirubin conjugation deficient rat.

Role of Liver Progenitor Cell in Liver Regeneration Cellular Cross-Talks and Signals

The liver is well known for its ability to regenerate in response to injury. After partial hepatectomy and some chemicals induced acute liver injury, existing hepatocytes can expand to repair the liver function. While adult liver stem/progenitor cells(LPCs) are evoked and differentiate into functional hepatocytes and cholangiocytes to compensate the damaged liver once hepatocyte proliferation is severely impaired. A number of evidences suggest that adjacent hepatic stellate cells(HSCs) or invading leukocytes may be involved in LPCs directed regeneration through governning two major events including fibrogenic and inflammatory responses respectively or simultaneously. As such, a microenvironment(or "niche") composed of different cell sources or factors presents diversity, which eventually mediates LPCs response to biliary or hepatocellular regeneration. This mini review aims at summarizing the latest development on the roles of HSCs, macrophages and lymphocytes as well as corresponding signaling pathways in liver progenitor cells mediated biliary and hepatocellular regeneration, and discussing therapeutic potential of liver progenitor cells in hepatic diseases.

Bone marrow progenitor cells do not contribute to liver fibrogenic cells

AIM:To investigate the contribution of bone marrow(BM) cells to hepatic fibrosis.METHODS:To establish a model of chimerism,C57Bl/6 female mice were subjected to full-body irradiation(7 Gy) resulting in BM myeloablation.BM mononuclear cells obtained from male transgenic mice expressing enhanced green fluorescent protein(GFP) were used for reconstitution.Engraftment was confirmed by flow cytometry.To induce liver injury,chimeric animals received carbon tetrachloride(CCl4) 0.5 mL/kg intraperitoneally twice a week for 30 d(CCl4 30 d) and age-matched controls received saline(Saline 30 d).At the end of this period,animals were sacrificed for post mortem analysis.Liver samples were stained with hematoxylin and eosin to observe liver architectural changes and with Sirius red for collagen quantification by morphometric analysis.α-smooth muscle actin(α-SMA) was analyzed by confocal microscopy to identify GFP+ cells with myofibroblast(MF) characteristics.Liver tissue,BM and peripheral blood were collected and prepared for flow cytometric analysis using specific markers for detection of hepatic stellate cells(HSCs) and precursors from the BM.RESULTS:Injury to the liver induced changes in the hepatic parenchymal architecture,as reflected by the presence of inflammatory infiltrate and an increase in collagen deposition(Saline 30 d = 11.10% ± 1.12% vs CCl4 30 d = 12.60% ± 0.73%,P = 0.0329).Confocal microscopy revealed increased reactivity against α-SMA in CCl4 30 d compared to Saline 30 d,but there was no co-localization with GFP+ cells,suggesting that cells from BM do not differentiate to MFs.Liver flow cytometric analysis showed a significant increase of CD45+/GFP+ cells in liver tissue(Saline 30 d = 3.2% ± 2.2% vs CCl4 30 d = 5.8% ± 1.3%,P = 0.0458),suggesting that this increase was due to inflammatory cell infiltration(neutrophils and monocytes).There was also a significant increase of common myeloid progenitor cells(CD117+/CD45+) in the livers of CCl4-treated animals(Saline 30 d = 2.16% ± 1.80% vs CCl4 30 d = 5.60% ± 1.30%,P = 0.0142).In addition the GFP-/CD38+/CD45-subpopulation was significantly increased in the CCl4 30 d group compared to the Saline 30 d group(17.5% ± 3.9% vs 9.3% ± 2.4%,P = 0.004),indicating that the increase in the activated HSC subpopulation was not of BM origin.CONCLUSION:BM progenitor cells do not contribute to fibrosis,but there is a high recruitment of inflammatory cells that stimulates HSCs and MFs of liver origin.? 2012 Baishideng.All rights reserved.

The combination of epidermal growth factor and glycogen synthase kinase 3 inhibitor support long-term self-renewal of Sca-1 positive hepatic progenitor cells from normal adult mice

Isolation and long-term maintenance of hepatic progenitor cells (HPCs) from healthy, non-injured adult livers remains challenging due to the lack of specific surface markers for selection and a limited understanding of the mechanisms for maintaining self-renewal. Previously, we identified a Sca-1 positive, bipotent HPC population in the peri-portal region of adult liver, and found MAPK/ERK and Wnt/β-Catenin pathways to be synergistically involved in their proliferation. In this study, we report the long-term culture of Sca-1 positive HPCs with epidermal growth factor (EGF) and CHIR99021, a small molecule inhibitor of glycogen synthase kinase 3 (GSK-3). Sca-1+ HPCs remain non-tumorigenic when passaged 35 times in vitro over 1 year. Flow cytometric analysis indicates that HPCs are positive for Sca-1 and putative liver progenitor cell markers, including CD13, CD24 and Prominin-1, but negative for hematopoietic/endothelial cell markers CD31, CD34, CD45, CD90 and CD117. Immunocyto-chemistry and RT-PCR indicate Sca-1+ HPCs express albumin (ALB), α-fetoprotein (AFP), cytokeratin19 (CK19), Sox9 and a panel of special hepatic progenitor transcriptional factors. Moreover, Sca-1+ HPCs are able to differentiate into hepatocyte-like and cholangiocyte-like cells under appropriate culture conditions in vitro and can take part in liver repopulation in an acetaminophen (APAP) induced liver injury mouse model. This study provides a paradigm to capture and maintain HPCs from naive liver tissue and offers a valuable cell model for investigating the molecular mechanisms underlying the cell lineage relationship in normal liver.

NLR’s Analogs with Young Blood Cells in Monitoring of Toxicity of Long-Term Preventing Immunosuppression in the Liver Transplant’s Recipients

The blood neutrophils to lymphocytes ratio (NLR) reflects the physiological homeostasis between lymphopoiesis and myelopoiesis, and its elevation serves as a harmful sign in many pathologies, partially, late rejection of allograft. The stem and young lymphoid cells have regenerative-trophic properties, which can affect the relevance of NLR, being opposed to immune properties, associated with bulk lymphocytes. In the present article, we have analyzed for the first time the applicability of NLR’s analogs with stem and immature blood cells for monitoring harmful long-term shifting from lymphopoiesis to myelopoiesis in transplant’s recipients received conventional immunosuppressive treatment. In opposition to conventional NLR, the ratio of subpopulation of CD31 cells committed to the liver tissue by alfa-fetoprotein (AFP), seems sensitive enough for such monitoring several years after transplantation of the liver from the dead.

road to stemness in hepatocellular carcinoma

Carcinogenic process has been proposed to relay on the capacity to induce local tissue damage and proliferative repair. Liver has a great regeneration capacity and currently, most studies point towards the dominant role of hepatocytes in regeneration at all levels of liver damage. The most frequent liver cancer is hepatocellular carcinoma(HCC). Historical findings originally led to the idea that the cell of origin of HCC might be a progenitor cell. However, current linage tracing studies put the progenitor hypothesis of HCC origin into question. In agreement with their dominant role in liver regeneration, mature hepatocytes are emerging as the cell of origin of HCC, although, the specific hepatocyte subpopulation of origin is yet to be determined. The relationship between the cancer cell of origin(CCO) and cancer-propagating cells, known as hepatic cancer stem cell(HCSC) is unknown. It has been challenging to identify the definitive phenotypic marker of HCSC, probably due to the existence of different cancer stem cells(CSC) subpopulations with different functions within HCC. There is a dynamic interconversion among different CSCs, and between CSC and non-CSCs. Because of that, CSC-state is currently defined as a description of a highly adaptable and dynamic intrinsic property of tumor cells, instead of a static subpopulation of a tumor. Altered conditions could trigger the gain of stemness, some of them include: EMT-MET, epigenetics, microenvironment and selective stimulus such as chemotherapy. This CSC heterogeneity and dynamism makes them out reach from therapeutic protocols directed to a single target. A further avenue of research in this line will be to uncover mechanisms that trigger this interconversion of cell populations within tumors and target it.

maturity of associating liver partition and portal vein ligation for staged hepatectomy-derived liver regeneration in a rat model

AIM To establish a rat model for evaluating the maturity of liver regeneration derived from associating liver partition and portal vein ligation for staged hepatectomy(ALPPS).METHODS In the present study, ALPPS, partial hepatecotmy(PHx), and sham rat models were established initially, which were validated by significant increase of proliferative markers including Ki-67, proliferating cell nuclear antigen, and cyclin D1. In the setting of accelerated proliferation in volume at the second and fifth day after ALPPS, the characteristics of newborn hepatocytes, as well as specific markers of progenitor hepatic cell, were identified. Afterwards, the detection of liver function followed by cluster analysis of functional gene expression were performed to evaluate the maturity.RESULTS Compared with PHx and sham groups, the proliferation of f LR was significantly higher in ALPPS group(P = 0.023 and 0.001 at second day, P = 0.034 and P < 0.001 at fifth day after stage I). Meanwhile, the increased expression of proliferative markers including Ki-67, proliferating cell nuclear antigen, and cyclin D1 verified the accelerated liver regeneration derived from ALPPS procedure. However, ALPPS-induced Sox9 positive hepatocytes significantly increased beyond the portal triad, which indicated the progenitor hepatic cell was potentially involved. And the characteristics of ALPPSinduced hepatocytes indicated the lower expression of hepatocyte nuclear factor 4 and anti-tryptase in early proliferative stage. Both suggested the immaturity of ALPPS-derived liver regeneration. Additionally, the detection of liver function and functional genes expression confirmed the immaturity of renascent hepatocytes derived in early stage of ALPPS-derived liver regeneration.CONCLUSION Our study revealed the immaturity of ALPPS-derived proliferation in early regenerative response, which indicated that the volumetric assessment overestimated the functional proliferation. This could be convincing evidence that the stage Ⅱ of ALPPS should be performed prudently in patients with marginally adequate f LR, as the ALPPS-derived proliferation in volume lags behind the functional regeneration.

Stimulation of oval cell and hepatocyte proliferation by exogenous bombesin and neurotensin in partially hepatectomized rats

AIM:To investigate the effect of the neuropeptides bombesin(BBS)and neurotensin(NT)on oval cell proliferation in partially hepatectomized rats not pretreated with a known hepatocyte inhibitor.METHODS:Seventy male Wistar rats were randomly divided into five groups:Ⅰ=controls,Ⅱ=sham operated,Ⅲ=partial hepatectomy 70%(PHx),Ⅳ=PHx+ BBS(30μg/kg per day),Ⅴ=PHx+NT(300μg/kg per day).Forty eight hours after liver resection,portal en-dotoxin levels and hepatic glutathione redox state were determined.α-fetoprotein(AFP)mRNA(in situ hybridisation),cytokeratin-19 and Ki67 antigen expression (immunohistochemistry)and apoptosis(TUNEL)were evaluated on liver tissue samples.Cells with morphological features of oval cells that were cytokeratin-19 (+)and AFP mRNA(+)were scored in morphometric analysis and their proliferation was recorded.In addition,the proliferation and apoptotic rates of hepatocytes were determined.RESULTS:In the control and sham operated groups,oval cells were significantly less compared to groups Ⅲ,ⅣandⅤ(P<0.001).The neuropeptides BBS and NT significantly increased the proliferation of oval cells compared to groupⅢ(P<0.001).In addition,BBS and NT induced a significant increase of hepatocyte proliferation(P<0.001),whereas it decreased their apoptotic activity(P<0.001)compared to groupⅢ.BBS and NT significantly decreased portal endotoxemia (P<0.001)and increased the hepatic GSH:GSSG ratio (P<0.05 and P<0.001,respectively)compared to groupⅢ.CONCLUSION:BBS and NT stimulated oval cell proliferation in a model of liver regeneration,without use of concomitant suppression of hepatocyte proliferation as oval cell activation stimuli,and improved the hepatocyte regenerative response.This peptides-induced combined stimulation of oval cell and hepatocyte proliferation might serve as a possible treatment modality for several liver diseases.

序贯使用VEGF及EPC在改善肝脏缺血再灌注损伤中的作用

目的探讨序贯使用血管内皮生长因子(VEGF)及血管内皮祖细胞(EPC)在改善肝脏缺血再灌注损伤(IRI)中的作用。方法取8只健康Wistar大鼠进行骨髓EPC的分离、培养和鉴定。取28只健康Wistar大鼠建立肝脏IRI大鼠模型,按随机数字表法分为VEGF+EPC组、VEGF组、EPC组及手术对照组,每组各7只;经肠系膜静脉属支注射药物:VEGF+EPC组序贯注射重组大鼠VEGF因子及EPC细胞悬液,VEGF组注射重组大鼠VEGF因子和PBS液,EPC组注射PBS液和EPC细胞悬液,手术对照组仅注射PBS液。比较4组大鼠1周存活率、肝功能、血液VEGF水平、肝组织髓过氧化物酶(MPO)水平及病理变化情况。结果贴壁细胞CD133、CD34及血管内皮生长因子受体2阳性率分别为90.51%、93.23%及93.41%,说明成功分离出骨髓EPC细胞。各组大鼠1周存活率比较,差异无统计学意义(P>0.05);1周后VEGF+EPC组大鼠ALT、乳酸脱氢酶(LDH)、TBil水平显著低于VEGF组和EPC组(均P<0.01);VEGF水平显著高于VEGF组和EPC组(均P<0.01);肝组织病理检查见VEGF+EPC组肝细胞轻度水肿,肝索结构正常,未见明显炎性细胞聚集、肝细胞坏死等病理改变;肝组织中MPO水平显著低于VEGF组和EPC组(均P<0.01)。结论对肝脏IRI大鼠序贯使用VEGF及EPC,虽不能提高大鼠存活率,但能改善大鼠肝功能,减轻肝脏组织炎症,对肝脏IRI的治疗有利。

气道类器官研究哮喘中Lkb1调控上皮再生的机制

目的 通过气道类器官培养研究哮喘中肝激酶B1(Lkb1)调控上皮再生的机制。方法 取Lkb1~(f/f)(对照组,10只)和Scgb1a1~(CreER);Lkb1~(f/f)小鼠(Lkb1敲除组,9只),采用雾化吸入鸡卵清蛋白(OVA)的方法建立过敏性哮喘模型,收集支气管肺泡灌洗液(BALF)和肺组织,统计BALF中炎性细胞数量,肺组织切片免疫荧光染色比较钙激活氯离子通道蛋白3(CLCA3)阳性细胞数量。通过流式细胞术分选出Club细胞进行类器官培养,统计类器官的平均直径和类器官形成率,回收细胞通过实时荧光定量PCR(RT-PCR)技术检测高脚杯细胞标志物CLCA3、纤毛细胞标志物叉头框蛋白J1(FOXJ1)和Club细胞中腺苷酸活化蛋白激酶(AMPK)的表达水平。结果 与对照组相比,Lkb1敲除组BALF中巨噬细胞、嗜酸性粒细胞、中性粒细胞和淋巴细胞数量变化差异无统计学意义;Lkb1敲除后CLCA3阳性细胞数量减少;类器官培养结果显示敲除Lkb1后Club细胞来源的类器官平均直径减小,类器官形成率降低,纤毛细胞分化标志物FOXJ1 m RNA表达水平降低,缺失Lkb1后Club细胞表达AMPKα水平降低,且Club细胞增殖受到抑制,激活Lkb1的下游信号通路AMPK可以减弱Lkb1缺失对Club细胞再生功能的影响。结论 Lkb1通过AMPK通路促进气道祖细胞增殖。

肝巨噬细胞调控肝癌癌前病变恶变的研究进展

肝巨噬细胞是肝脏中重要的免疫细胞,其通过极化为M1型和M2型,分别表达“促炎因子”和“抑炎因子”,进而发挥调控炎症损伤反应的作用。肝祖细胞恶变是肝癌癌前病变恶性进展的核心机制,其发生的关键因素是炎症损伤微环境的持续刺激,与M1/M2巨噬细胞极化密切相关。本综述主要围绕“巨噬细胞极化-慢性炎症-肝祖细胞恶变”关系进行探讨,为肝癌癌前病变的预防和治疗提供重要的理论依据。

肝癌细胞系中circAMOTL1的表达及对肝前体细胞增殖和恶性转化的影响

目的探讨环状RNA circAMOTL1在肝癌细胞系中的表达及其对肝前体细胞(HPCs)系WB-F344的增殖迁移及恶性转化的影响。方法通过实时荧光定量PCR检测circAMOTL1在5种肝癌细胞系和正常肝细胞系L-02以及HPCs系WB-F344中的表达;同时构建过表达和敲除circAMOTL1的WB-F344的细胞系;通过CCK-8实验检测过表达或敲除cAMOTL1后HPCs的增殖变化;细胞划痕实验验证细胞迁移的变化;通过蛋白免疫印迹实验验证过表达或敲除circAMOTL1后对肝癌干细胞(LCSCs)标志物CD133的表达影响。结果5种肝癌细胞系中circAMOTL1的表达水平均高于L-02(P<0.05);过表达circAMOTL1后HPCs的增殖能力显著提高(P<0.01),敲除circAMOTL1后细胞的增殖能力显著下降(P<0.001);过表达circAMOTL1后显著提升了细胞的迁移能力(P<0.01),敲除后细胞的迁移能力明显下降(P<0.01);过表达circAMOTL1后可以检测到CD133的表达。结论circAMOTL1在5种肝癌细胞系中高表达,过表达circAMOTL1可以促进HPCs的增殖和迁移能力,诱导其向LCSCs方向恶性转化。

肝祖细胞移植对四氯化碳诱导急性肝衰竭小鼠模型肝损伤的修复作用

目的:观察肝祖细胞(HPCs)移植后不同浓度四氯化碳(CCl4)诱导的急性肝衰竭小鼠模型肝脏修复情况,评价HPCs对肝损伤的修复能力,为评估HPCs移植疗效建立理想的肝衰竭模型。方法:96只ICR小鼠随机分为空白对照组、阴性对照组(0.1%CCl4组、0.5%CCl4组、2.0%CCl4组、10.0%CCl4组)和实验组(0.1%CCl4+HPCs组、0.5%CCl4+HPCs组、2.0%CCl4+HPCs组和10.0%CCl4+HPCs组)。空白对照组小鼠灌胃给予生理盐水,阴性对照组和实验组小鼠灌胃给予不同剂量CCl4。CCl4造模后1d,将实验组和阴性对照组小鼠常规麻醉后切开腹腔,实验组小鼠经脾脏注射HPCs,阴性对照组小鼠注射等剂量无菌生理盐水。动态观察小鼠生命体征,监测其存活率;采血检测小鼠血清天门冬氨酸氨基转移酶(AST)和丙氨酸转氨酶(ALT)活性;取肝脏计算肝脏指数;HE染色观察各组小鼠肝脏组织病理学变化;Hoechst33342标记外源性HPCs,激光共聚焦显微镜检测移植HPCs在肝脏中的分布情况及肝脏标志蛋白细胞角蛋白18(CK18)和白蛋白(ALB)的表达。结果:与空白对照组比较,0.1%和0.5%CCl4组小鼠存活率、肝脏指数、AST和ALT活性无明显变化(P>0.05)。病理学检测,肝细胞有自我修复作用,HPCs移植治疗的效果不明显。与2.0%CCl4组比较,2.0%CCl4+HPCs组小鼠AST和ALT活性及肝脏指数降低(P<0.01),存活率增加(P<0.01);病理学检测可见肝细胞再生和大量外源性肝细胞,CK18和ALB表达与内源性肝细胞相当,HPCs移植治疗有效。10.0%CCl4组和10.0%CCl4+HPCs组小鼠2d内全部死亡,无法评估HPCs的治疗效果。结论:HPCs移植可提高急性肝衰竭模型小鼠存活率,改善AST和ALT活性,对肝损伤具有较强的修复能力;且2.0%CCl4诱导的ICR小鼠急性肝衰竭模型能有效反映HPCs移植治疗的效果。

大鼠肝干细胞的分离培养

目的 分离大鼠胎肝细胞,观察人肝细胞生长肽(HGP)和小鼠白血病抑制因子(mLIF)对其生长和肝干细胞集落形成的影响。方法 从大鼠胚胎(12日龄)肝中分离肝细胞,采用MTT比色法、~3H-TdR掺入法和碱性磷酸酶(AKP)检测法。结果 人HGP能剂量依赖性地促进胎肝细胞的DNA合成和增殖,500～2000u/ml的mLIF能明显促进肝干细胞集落的生长和维持未分化状态。肝干细胞培养基的组成为:5％FBS(国产或进口),10％国产NCS,0.14mM的β-ME,40ng/ml伴白蛋白,10ng/ml的人bFGF,0.5μg～1.0μg/ml的HGP,1000u/ml mLIF,1％非必需氨基酸的高糖DMEM培养基。AKP染色阳性细胞在上述培养基中传至6代仍生长良好和保持未分化状态。结论 从胎鼠肝中能分离到肝干细胞,人HGP能促进鼠胎肝细胞的生长,而mLIF对促进肝干细胞生长和维持未分化是必要的。

MafA逆转录病毒表达载体的构建及其在肝原始细胞中的稳定表达

目的:构建表达MafA(v-maf musculoaponeurotic fibrosarcoma oncogene homologue A)的逆转录病毒表达载体,并建立稳定表达MafA的肝原始细胞系(liver epithelial progenitor cells,LEPCs)。方法:通过PCR方法克隆MafA基因全长.将其构建到pBMN—Z—IRES-Neo逆转录病毒载体中获得pBMN—MafA—Neo载体;将该载体导入Phoenix包装细胞系,收集病毒上清并感染LEPCs,筛选稳定表达MafA的LEPCs;RT-PCR方法检测MafA表达对LEPCs分子表型的影响。结杲:成功构建pBMN—MafA-Neo载体,并获得稳定表达MafA基因的肝原始细胞系(LEPCs—MafA)。LEPCs-MafA细胞GK和GLUT2基因表达高于LEPCs。结论:成功获得稳定表达MafA的肝原始细胞系,为研究MafA诱导肝干细胞向胰腺细胞转分化奠定了基础。