重组人蛋白C在HEK293细胞中的表达与鉴定

目的获得转染人蛋白CcDNA的工程细胞株,实现重组蛋白C的表达。方法将构建好的重组表达载体pIRES-hPC用脂质体介导的方法转染HEK293细胞,经G418加压筛选、细胞有限稀释法等获得克隆细胞株,收集无血清培养上清,浓缩后进行鉴定。结果经G418筛选得到了21株克隆化细胞,SDS-PAGE和Westernblot鉴定表明,表达产物含有人蛋白C,且具有抗凝活性。结论在哺乳动物细胞中已成功表达重组人蛋白C,为进一步深入研究及产业化奠定了基础。     

首批HEK293细胞DNA含量测定国家标准品的制备

目的 制备HEK293细胞DNA含量测定用国家标准品,以期为行业内HEK293细胞残余DNA的测定提供支持。方法 使用Genomic-tip 500/G以及基因组DNA纯化试剂制备HEK293细胞DNA,以其为标准物质原料,采用紫外分光光度法和琼脂糖凝胶电泳法进行纯度和含量筛选,随后稀释至浓度约为100 ng/μL后,按160μL/支进行分装。组织5家不同实验室,采用紫外分光光度法进行协作标定,并评价其稳定性和适用性。结果 制备的HEK293细胞DNA国家标准品经检测,A₂₆₀/A₂₈₀均在1.8～2.0之间,电泳图谱为单一条带,符合规定。该标准品经5家实验室协作标定,共得到78个有效数据,平均含量为104.8 ng/μL,相对标准偏差(relative standard deviation,RSD)为4.2%,均数的95%可信区间为103.8～105.8 ng/μL,单次测定的95%参考值范围为96.0～113.6 ng/μL,平均可信限率为1.0%,推荐保存条件为-80℃。采用2个不同型号的荧光定量PCR仪进行适用性研究,该标准品在0.3...     

人Makorin环指蛋白1基因沉默对HEK293细胞的影响

目的探讨特异性抑制人Makorin环指蛋白1(MKRN1)基因的表达对HEK293细胞的影响。方法用脂质体将前期筛选出的含最有效干扰序列的人MKRN1基因shRNA真核表达质粒,转染至HEK293细胞中,观察其对人端粒酶逆转录酶(hTERT)基因mRNA转录水平、蛋白表达水平及细胞增殖的影响。结果人MKRN1基因shRNA真核表达质粒转染HEK293细胞后,在mRNA和蛋白水平均能明显上调细胞hTERT基因的表达,且细胞明显增殖。结论抑制HEK293细胞中人MKRN1基因的表达,可导致hTERT基因mRNA转录水平和蛋白表达水平上调,并促进细胞增殖。     

UL27基因shRNA表达载体对293细胞转染效率的优化

旨在优化Lipofectamine2000试剂介导UL27基因重组质粒p GPU6/GFP/Neo-UL27shRNA转染HEK293细胞的条件,为研究UL27基因重组质粒对HSV-2的干扰作用奠定基础。用Lipofectamine2000试剂介导p GPU6/GFP/Neo-UL27shRNA重组质粒转染293细胞,采用流式细胞仪检测不同的转染时间下的转染效率,同时荧光显微镜和流式细胞仪检测不同比例条件下的转染效率,MTT法检测细胞的存活率。在质粒与转染试剂复合物的配比为0.8μg∶2μL,转染48 h,转染效率最高并且对细胞毒性最小。优化p GPU6/GFP/Neo-UL27shRNA转染293细胞的条件,提高了转染效率。     

单纯疱疹病毒2型UL27和UL29双基因shRNA慢病毒表达载体的构建及其在HEK293细胞中的表达

目的构建单纯疱疹病毒2型(herpes simplex virus type 2,HSV-2)UL27和UL29双基因shRNA慢病毒表达载体,并检测其在HEK293细胞中的表达。方法针对HSV-2 UL27、UL29基因,各筛选干扰效率最佳的shRNA片段相连接,构建双基因共表达慢病毒载体,并转染HEK293细胞作为干扰组,另设空白对照组(不做任何处理)和阴性对照组(转染不针对任何基因的慢病毒载体)。转染48或24 h后接种HSV-2,RT-PCR和Western blot法检测各组细胞中目的基因mRNA和蛋白的表达水平,MTT法检测各组细胞的存活率。结果干扰组UL27和UL29基因mRNA的表达抑制率可达(78.61±2.14)%和(84.86±1.52)%,同时gB和ICP8蛋白的相对表达量明显下降(P均<0.05),细胞的存活明显率提高(P均<0.05)。结论构建的HSV-2 UL27、UL29双基因shRNA重组慢病毒表达载体能在HEK293细胞中表达,为后续HSV-2的基因治疗奠定了实验基础。     

聚肌苷酸胞苷酸在HEK293T和BEAS-2B细胞中激活干扰素β荧光素酶报告基因系统实验条件的优化

目的优化不同长度聚肌苷酸胞苷酸[polyinosinic acid:polycytidylic acid,poly(I∶C)]在HEK293T和BEAS-2B细胞中激活Ⅰ型干扰素(IFNβ)荧光素酶报告基因系统的实验条件。方法将质粒IFN-β-luc分别转染HEK293T及BEAS-2B细胞后,HEK293T细胞转染不同浓度(0.25、0.5、1.0、1.5和2.0μg/孔)的高分子量(HMW)poly(I∶C)和低分子量(LMW)poly(I∶C),检测其对HEK293T细胞中IFNβ启动子激活的影响;BEAS-2B细胞直接加入不同浓度(0.1、1.0、10.0、20.0和50.0μg/孔)及转染不同浓度(同HEK293T细胞)的HMW poly(I∶C)和LMW poly(I∶C),检测其对BEAS-2B细胞中IFNβ启动子激活的影响。结果 poly(I∶C)转染HEK293T细胞激活IFNβ启动子的最佳实验条件为:0.5μg/孔的HMW poly(I∶C)和LMW poly(I∶C)转染24 h。poly(I∶C)直接加入BEAS-2B细胞激活IFNβ启动子的最佳实验条件为:50μg/孔的HMW poly(I∶C)和LMW poly(I∶C)作用6 h;poly(I∶C)转染BEAS-2B细胞激活IFNβ启动子的最佳实验条件为:0.25μg/孔的HMW poly(I∶C)转染12 h,0.5μg/孔的LMW poly(I∶C)转染12 h。结论成功优化了poly(I∶C)在HEK293T和BEAS-2B细胞中激活IFNβ启动子的实验条件,为poly(I∶C)激活免疫反应机制的研究提供了实验依据。     

真核重组表达质粒pTT5-CTP-PTEN的构建及其在HEK 293-6E细胞中的表达

目的构建真核重组表达质粒pTT5-CTP-PTEN,并在HEK 293-6E细胞中进行表达。方法合成融合基因CTP-PTEN,定向克隆至真核表达载体pTT5中,构建重组表达质粒pTT5-CTP-PTEN,转化感受态E.coli DH5α,提取质粒,进行双酶切及测序鉴定。在Lipofectamine 2000的介导下,将鉴定正确的重组表达质粒转染至HEK 293-6E细胞,Western blot法检测细胞中融合蛋白CTP-PTEN的表达。结果经双酶切及测序鉴定,证明重组表达质粒pTT5-CTPPTEN构建正确。转染48 h后,HEK 293-6E细胞中可见相对分子质量约49 700的CTP-PTEN融合蛋白条带。结论成功构建了重组质粒pTT5-CTP-PTEN,并于HEK 293-6E细胞中表达了CTP-PTEN融合蛋白。     

干扰素诱导跨膜蛋白2对脑心肌炎病毒体外增殖的影响

目的 探讨干扰素诱导跨膜蛋白2(interferon induced transmembrane proteins 2,IFITM2)对脑心肌炎病毒(encephalomyocarditis virus,EMCV)体外增殖的影响.方法 将重组表达质粒pcDNA3.1-IFITM2及靶向IFITM2的siRNA序列分别转...     

RNA聚合酶Ⅱ转录的ALU序列对HEK293细胞凋亡的影响

目的探讨RNA聚合酶Ⅱ转录的ALU序列对人胚肾293(HEK293)细胞凋亡的影响以及干扰素(IFN)在此机制中的作用。方法取对数生长期的HEK293细胞,分为6组,ALU-293组(瞬时转染重组质粒pcDNA3.1-ALU)、pcDNA3.1-293组[瞬时转染空质粒pcDNA3.1(-),作为阴性对照]、Poly I∶C-293组[瞬时转染dsRNA的多聚肌苷胞苷酸(Poly I∶C),作为阳性对照]、IFNβ-293组(加入1.65×104 U IFNβ,作为阳性对照)、空白对照组(未经处理的HEK293细胞)和HBs-293组(瞬时转染重组质粒pcDNA3.1-HBs),转染后48 h,采用MTT法检测细胞的增殖活性;Cellular DNA Fragmentation ELISA和DNA Ladder法检测细胞的凋亡情况;Real-time PCR检测细胞中IFNβ基因mRNA的水平。结果瞬时转染重组质粒pcDNA3.1-ALU能够抑制HEK293细胞增殖,并促使其凋亡,且细胞中IFNβmRNA的水平显著上调。结论 RNA聚合酶Ⅱ转录的ALU序列能够通过激活干扰素系统来诱导细胞凋亡。     

小鼠Fancd2os基因真核表达质粒的构建及其对人胚肾上皮细胞增殖和凋亡的影响

目的构建小鼠Fancd2os基因的真核表达质粒,并分析Fancd2os基因对人胚肾上皮细胞(HEK293T)增殖和凋亡的影响。方法以小鼠睾丸组织DNA为模板扩增Fancd2os基因c DNA全长片段,并克隆至真核表达载体p3×FLAG-CMV-14,构建重组真核表达质粒p3×FLAG-CMV-14-Fancd2os。经Lipofectamine TM 2000将重组真核表达质粒瞬时转染HEK293T细胞,分别采用RT-PCR及Western blot法检测转染细胞中Fancd2os基因m RNA转录及蛋白表达情况;经CCK8法和流式细胞术分别检测过表达Fancd2os对HEK293T细胞增殖能力及紫外线诱导HEK293T细胞凋亡的影响。结果经双酶切及测序鉴定,重组真核表达质粒p3×FLAG-CMV-14-Fancd2os构建正确;转染p3×Flag-CMV-14-Fancd2os的HEK293T细胞可见Fancd2os基因m RNA转录及其蛋白表达;过表达Fancd2os的HEK293T细胞的增殖活性显著下降(P0.05);过表达Fancd2os可显著促进紫外线诱导的HEK293T细胞凋亡(P0.01)。结论成功构建了重组真核表达质粒p3×Flag-CMV-14-Fancd2os,过表达Fancd2os可抑制HEK293T细胞的增殖,促进其凋亡。     

Effects of Cell Density and Microenvironment on Stem Cell Mitochondria Transfer among Human Adipose-Derived Stem Cells and HEK293 Tumorigenic Cells

Stem cells (SC) are largely known for their potential to restore damaged tissue through various known mechanisms. Among these mechanisms is their ability to transfer healthy mitochondria to injured cells to rescue them. This mitochondrial transfer plays a critical role in the healing process. To determine the optimal parameters for inducing mitochondrial transfer between cells, we assessed mitochondrial transfer as a function of seeding density and in two-dimensional (2D) and semi three-dimensional (2.5D) culture models. Since mitochondrial transfer can occur through direct contact or secretion, the 2.5D culture model utilizes collagen to provide cells with a more physiologically relevant extracellular matrix and offers a more realistic representation of cell attachment and movement. Results demonstrate the dependence of mitochondrial transfer on cell density and the distance between donor and recipient cell. Furthermore, the differences found between the transfer of mitochondria in 2D and 2.5D microenvironments suggest an optimal mode of mitochondria transport. Using these parameters, we explored the effects on mitochondrial transfer between SCs and tumorigenic cells. HEK293 (HEK) is an immortalized cell line derived from human embryonic kidney cells which grow rapidly and form tumors in culture. Consequently, HEKs have been deemed tumorigenic and are widely used in cancer research. We observed mitochondrial transfer from SCs to HEK cells at significantly higher transfer rates when compared to a SC–SC co-culture system. Interestingly, our results also revealed an increase in the migratory ability of HEK cells when cultured with SCs. As more researchers find co-localization of stem cells and tumors in the human body, these results could be used to better understand their biological relationship and lead to enhanced therapeutic applications.     

重组腺病毒生产技术研究进展

目前基因治疗,尤其是对癌症的基因治疗越来越多地得到人们的关注. 随着基因工程技术的发展,对癌症在基因水平上的认识不断深化,发现了很多对治疗癌症有帮助的基因,但临床面临的最大问题就是如何建立一个安全、高效、实用、可重复的基因转移系统,将这些治疗基因有效地导入靶细胞. 人们构建了各种载体,重组腺病毒就是基因治疗的重要载体之一. 能否生产出大量高质量的腺病毒载体是制约体外实验和临床实验的关键因素. 本文从感染机制、生产和纯化计数等几个方面讨论生产重组腺病毒载体的进展.     

Proteomic Landscape of Adeno-Associated Virus (AAV)-Producing HEK293 Cells

Adeno-associated viral (AAV) vectors are widely used for gene therapy, providing treatment for diseases caused by absent or defective genes. Despite the success of gene therapy, AAV manufacturing is still challenging, with production yields being limited. With increased patient demand, improvements in host cell productivity through various engineering strategies will be necessary. Here, we study the host cell proteome of AAV5-producing HEK293 cells using reversed phase nano-liquid chromatography and tandem mass spectrometry (RPLC-MS/MS). Relative label-free quantitation (LFQ) was performed, allowing a comparison of transfected vs. untransfected cells. Gene ontology enrichment and pathway analysis revealed differential expression of proteins involved in fundamental cellular processes such as metabolism, proliferation, and cell death. Furthermore, changes in expression of proteins involved in endocytosis and lysosomal degradation were observed. Our data provides highly valuable insights into cellular mechanisms involved during recombinant AAV production by HEK293 cells, thus potentially enabling further improvements of gene therapy product manufacturing.     

感染复数对Sabin株脊髓灰质炎病毒在Vero细胞中增殖的影响

目的观察不同感染复数(MOI)对Sabin株脊髓灰质炎病毒在Vero细胞中增殖的影响。方法分别用Ⅰ、Ⅱ、Ⅲ型Sabin株脊髓灰质炎病毒感染Vero细胞,观察不同MOI致细胞病变情况,并检测病毒滴度。结果病毒感染Vero细胞后48h,3组MOI(0.001、0.01、0.1)细胞病变均达莞。Ⅰ型病毒增殖高峰出现在接种后72h,3组MOI病毒滴度分别为(8.690±0.190)、(8.690±0.190)和(8.315±0.185)lgCCID50/ml;Ⅱ型病毒增殖高峰出现在接种后96h,3组MOI病毒滴度分别为(8.355±0.097)、(8.440±0.310)和(8.285±0.155)lgCCID50/ml;Ⅲ型病毒增殖高峰出现在接种后48～96h,3组MOI病毒最高滴度分别为(7.500±0.250)、(7.500±0.250)和(7.750±0.250)lgCCID50/ml。结论不同MOI对3型病毒增殖影响不大,可以采用低MO(I0.001)制备疫苗。     

腺病毒载体介导的HSV-tk基因杀伤肿瘤细胞的研究

目的 探讨ＨＳＶ－ｔｋ基因对各种肿瘤细胞的杀伤作用及人、鼠瘤细胞对其敏感性及瘤细胞表面的αｖ 整合素对腺病毒载体转染的影响。方法用同源重组法构建 ＡｄＣＭＶ ｔｋ基因;蚀斑形成法对重组腺病毒进行扩增、 滴定;Ｘ－ｇａｌ染色法观察腺病毒转染率,结晶紫染色法检测 ＡｄＣＭＶｔｋ／ＧＣＶ的杀伤作用。结果 ＡｄＣＭＶｔｋ对肿瘤细胞 的杀伤强度在一定范围内与ＡｄＣＭＶｔｋ的剂量呈正相关;对人类的Ｈｅｌａ、ＧＲＣ、Ｈｅｐ－２瘤细胞达１００％转染所需的腺病 毒感染复数量（ｍｕｌｔｉｐｌｉｃｉｔｙ　ｏｆ　ｉｎｆｅｃｔｉｏｎ,ｍ．ｏ．ｉ）较鼠Ｌｅｗｉｓ、ＢＴＴ７３９瘤细胞的ＭＯＩ量低;在相同ＭＯＩ病毒量时,有αｖ整合 素的瘤细胞转染率高于无αｖ整合素的瘤细胞。结论ＡｄＣＭＶｔｋ／ＧＣＶ具有较明显的杀伤肿瘤细胞的作用,且有种属 差异,对人瘤细胞作用大于鼠瘤细胞,瘤细胞表面的αｖ整合素有利于腺病毒的转染。     

Comparative Analysis of CREB3 and CREB3L2 Protein Expression in HEK293 Cells

We performed a comparative analysis of two ER-resident CREB3 family proteins, CREB3 and CREB3L2, in HEK293 cells using pharmacological and genome editing approaches and identified several differences between the two. Treatment with brefeldin A (BFA) and monensin induced the cleavage of full-length CREB3 and CREB3L2; however, the level of the full-length CREB3 protein, but not CREB3L2 protein, was not noticeably reduced by the monensin treatment. On the other hand, treatment with tunicamycin (Tm) shifted the molecular weight of the full-length CREB3L2 protein downward but abolished CREB3 protein expression. Thapsigargin (Tg) significantly increased the expression of only full-length CREB3L2 protein concomitant with a slight increase in the level of its cleaved form. Treatment with cycloheximide and MG132 revealed that both endogenous CREB3 and CREB3L2 are proteasome substrates. In addition, kifunensine, an α-mannosidase inhibitor, significantly increased the levels of both full-length forms. Consistent with these findings, cells lacking SEL1L, a crucial ER-associated protein degradation (ERAD) component, showed increased expression of both full-length CREB3 and CREB3L2; however, cycloheximide treatment downregulated full-length CREB3L2 protein expression more rapidly in SEL1L-deficient cells than the full-length CREB3 protein. Finally, we investigated the induction of the expression of several CREB3 and CREB3L2 target genes by Tg and BFA treatments and SEL1L deficiency. In conclusion, this study suggests that both endogenous full-length CREB3 and CREB3L2 are substrates for ER-associated protein degradation but are partially regulated by distinct mechanisms, each of which contributes to unique cellular responses that are distinct from canonical ER signals.     

MLK3 Regulates Inflammatory Response via Activation of AP-1 Pathway in HEK293 and RAW264.7 Cells

Inflammation is a critically important barrier found in innate immunity. However, severe and sustained inflammatory conditions are regarded as causes of many different serious diseases, such as cancer, atherosclerosis, and diabetes. Although numerous studies have addressed how inflammatory responses proceed and what kinds of proteins and cells are involved, the exact mechanism and protein components regulating inflammatory reactions are not fully understood. In this paper, to determine the regulatory role of mixed lineage kinase 3 (MLK3), which functions as mitogen-activated protein kinase kinase kinase (MAP3K) in cancer cells in inflammatory response to macrophages, we employed an overexpression strategy with MLK3 in HEK293 cells and used its inhibitor URMC-099 in lipopolysaccharide (LPS)-treated RAW264.7 cells. It was found that overexpressed MLK3 increased the mRNA expression of inflammatory genes (COX-2, IL-6, and TNF-α) via the activation of AP-1, according to a luciferase assay carried out with AP-1-Luc. Overexpression of MLK3 also induced phosphorylation of MAPKK (MEK1/2, MKK3/6, and MKK4/7), MAPK (ERK, p38, and JNK), and AP-1 subunits (c-Jun, c-Fos, and FRA-1). Phosphorylation of MLK3 was also observed in RAW264.7 cells stimulated by LPS, Pam3CSK, and poly(I:C). Finally, inhibition of MLK3 by URMC-099 reduced the expression of COX-2 and CCL-12, phosphorylation of c-Jun, luciferase activity mediated by AP-1, and phosphorylation of MAPK in LPS-treated RAW264.7 cells. Taken together, our findings strongly suggest that MLK3 plays a central role in controlling AP-1-mediated inflammatory responses in macrophages and that this enzyme can serve as a target molecule for treating AP-1-mediated inflammatory diseases.