The cellular microenvironment and cytoskeletal actin dynamics in liver fibrogenesis

Hepatic stellate cells (HSCs) are the primary effector cells in liver fibrosis. In the normal liver, HSCs serve as the primary vitamin A storage cells in the body and retain a “quiescent” phenotype. However, after liver injury, they transdifferentiate to an “activated” myofibroblast-like phenotype, which is associated with dramatic upregulation of smooth muscle specific actin and extracellular matrix proteins. The result is a fibrotic, stiff, and dysfunctional liver. Therefore, understanding the molecular mechanisms that govern HSC function is essential for the development of anti-fibrotic medications. The actin cytoskeleton has emerged as a key component of the fibrogenic response in wound healing. Recent data indicate that the cytoskeleton receives signals from the cellular microenvironment and translates them to cellular function—in particular, increased type I collagen expression. Dynamic in nature, the actin cytoskeleton continuously polymerizes and depolymerizes in response to changes in the cellular microenvironment. In this viewpoint, we discuss the recent developments underlying cytoskeletal actin dynamics in liver fibrosis, including how the cellular microenvironment affects HSC function and the molecular mechanisms that regulate the actininduced increase in collagen expression typical of activated HSCs.     

三维培养结肠癌细胞的微流控芯片荧光成像研究

改良了一种微流控芯片,可用于对结肠癌细胞进行三维培养并实现实时荧光成像。在结肠癌细胞内植入内源性的红色荧光蛋白,使用激光共聚焦显微镜对芯片中三维培养的细胞进行成像。通过细胞内部红色荧光蛋白的表达,可以观测到细胞的生长状态,实现对细胞的实时监测和高分辨率荧光成像。同时,通过免疫荧光染色来表征反映细胞活性的特征蛋白,其荧光强度和蛋白表达呈正相关。研究结果提示,细胞活性相关蛋白的表达受到微环境的影响,其在芯片三维培养中的活性强于二维培养,表明芯片内环境更加接近真实的人体微环境。该方法为进一步探究肿瘤细胞转移机制及相关药物的筛选研究提供了一种新的技术手段及实验平台。     

干式DCT变速HEV换档过程鲁棒优化控制

针对双离合器自动变速器(Dual clutch transmission,DCT)变速弱混合动力轿车,考虑到起动发电一体化电机(Integrated starter and generator,ISG)转矩响应特性较快、转速/转矩控制精度高等特点,对其介入到换档过程时不同动力源输出转矩和离合器传递转矩协调鲁棒控制问题进行研究。建立体现DCT换档切换过程阶段差异性的动力学模型;考虑转矩相的离合器执行机构的响应能力和惯性相的模型不确定性和外界干扰(转速量测噪声和发动机转矩响应滞后),优化决策了动力源合成转矩;在需求转矩切换阶段,切换发动机转矩至驾驶员需求水平并退出ISG电机;基于系统效率最优对动力源合成转矩进行分配。基于Simulink的仿真试验表明所提出的换档控制策略能有效协调控制动力源转矩,并对模型不确定性和干扰有较强的抑制能力。为进一步验证策略进行的动态台架试验表明,所设计的转矩协调控制策略有效地解决了DCT换档过程中ISG电机、发动机以及双离合器之间的实时转矩协调控制问题,使其具有较好的换档品质。     

Cell membrane deformations under magnetic force modulation characterized by optical tracking and non-interferometric widefield profilometry

We measured cell membrane deformations under the modulation of piconewton magnetic force by using optical tracking and noninterferometric widefield optical profilometry. The magnetic force was applied to fibronectin-coated paramagnetic beads that bound to transmembrane protein integrins. At an image-acquisition rate of 20 frame/min, optical tracking provided positioning accuracy better than 70 nm for bead displacements on cell membranes, and optical profilometry obtained membrane topography with 20 nm depth resolution. We elucidated the correlation between the bead movements and membrane deformations. When the magnetic force dominated the bead movements, the membrane arose in front of the bead and the height increased with the bead velocity. On the other hand, when the bead was mainly driven by the cytoskeletons, the membrane profiles showed no relevance to the motion of the bead. In this case, the bead moved faster on smooth membranes. A model based on the dynamics of actin cytoskeletons is proposed to explain these observation results.     

WGCNA and LASSO algorithm constructed an immune infiltration-related 5-gene signature and nomogram to improve prognosis prediction of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common immunogenic malignant tumor. Although the new strategies of immunotherapy and targeted therapy have made considerable progress in the treatment of HCC, the 5-year survival rate of patients is still very low. The identification of new prognostic signatures and the exploration of the immune microenvironment are crucial to the optimization and improvement of molecular therapy strategies. We studied the potential clinical benefits of the inflammation regulator miR-93-3p and mined its target genes. Weighted gene co-expression network analysis (WGCNA), univariate and multivariate COX regression and the LASSO COX algorithm are employed to identify prognostic-related genes and construct multi-gene signature-based risk model and nomogram for survival prediction. Support vector machine (SVM) based Cibersort’s deconvolution algorithm and gene set enrichment analysis (GSEA) is used to evaluate the changes in tumor immune microenvironment and pathway differences. The study found the favorable prognostic performance of miR-93-3p and identified 389 prognostic-related target genes. The risk model based on a novel 5-gene signature (cct5, cdk4, cenpa, dtnbp1 and flvcr1) was developed and has prominent prognostic significance in the training cohort (P < 0.0001) and validation cohort (P = 0.0016). The nomogram constructed by combining the gene signature and the AJCC stage further improves the survival prediction ability of the gene signature. The infiltration level of multiple immune cells (especially T cells, B cells and macrophages) were positively correlated with the expression of prognostic signature. In addition, we found that gene markers of T cells and B cells is monitored and regulated by prognostic signature. Meanwhile, several GSEA pathways related to the immune system are enriched in the high-risk group. In general, we integrated the WGCNA, LASSO COX and SVM algorithms to develop and verify 5-gene signatures and nomograms related to immune infiltration to improve the survival prediction of patients.     

Proteomics analysis of tumor microenvironment: Implications of metabolic and oxidative stresses in tumorigenesis

Tumorigenesis is always concomitant with microenvironmental alterations. The tumor microenvironment is a heterogeneous and complex milieu, which exerts a variety of stresses on tumor cells for proliferation, survival, or death. Recently, accumulated evidence revealed that metabolic and oxidative stresses both play significant roles in tumor development and progression that converge on a common autophagic pathway. Tumor cells display increased metabolic autonomy, and the hallmark is the exploitation of aerobic glycolysis (termed Warburg effect), which increased glucose consumption and decreased oxidative phosphorylation to support growth and proliferation. This characteristic renders cancer cells more aggressive; they devour tremendous amounts of nutrients from microenvironment to result in an ever‐growing appetite for new tumor vessel formation and the release of more “waste,” including key determinants of cell fate like lactate and reactive oxygen species (ROS). The intracellular ROS level of cancer cells can also be modulated by a variety of stimuli in the tumor microenvironment, such as pro‐growth and pro‐inflammatory factors. The intracellular redox state serves as a double‐edged sword in tumor development and progression: ROS overproduction results in cytotoxic effects and might lead to apoptotic cell death, whereas certain level of ROS can act as a second‐messenger for regulation of such cellular processes as cell survival, proliferation, and metastasis. The molecular mechanisms for cancer cell responses to metabolic and oxidative stresses are complex and are likely to involve multiple molecules or signaling pathways. In addition, the expression and modification of these proteins after metabolic or oxidative stress challenge are diverse in different cancer cells and endow them with different functions. Therefore, MS‐based high‐throughput platforms, such as proteomics, are indispensable in the global analysis of cancer cell responses to metabolic and oxidative stress. Herein, we highlight recent advances in the understanding of the metabolic and oxidative stresses associated with tumor progression with proteomics‐based systems biology approaches. © 2012 Wiley Periodicals, Inc., Mass Spec Rev 32:267–311, 2013     

ISG型PHEV动力总成系统设计与仿真

为提高混合动力汽车燃油经济性和动力性,以ISG型并联式HEV为对象,以某型传统车参数为参考,根据整车运行功率需求,提出一种更加简便的方法来对其动力总成系统进行设计,对各总成部件进行了参数设计计算。提出了基于ADVISOR软件平台的Insight车型模型较为快捷的整车二次开发,对动力总成系统的设计值进行仿真测试。结果表明:所设计的ISG型PHEV动力总成部件能够满足匹配要求,可进一步提高整车的经济性和动力性,设计方法正确可行,提供了更为便捷地进行混合动力汽车实车研发的参考依据。     

混合动力电动汽车的建模与仿真研究

按照设计要求,以TJ7100轿车为设计原型,针对ISG型混合动力电动汽车(HEV),使用Simulink建立了其动力系统的动态仿真模型,重点研究并制定了相应的电力助动控制策略.在ECE循环工况下对仿真模型进行了动力性和燃油经济性分析,为搭建动力总成试验平台提供了参考依据.结果表明,所制定的控制策略能有效地较低燃油消耗,使电池SOC值维持在一定的范围内.同时,仿真结果与实际情况基本相符,从而验证了所建仿真模型的正确性和合理性.     

采用异步电机的42V汽车起动/发电机系统

论述基于异步电机和PWM变流器串联构成的42V汽车起动/发电机系统,采用转子磁场定向矢量控制方法使电机带动发动机顺利起动,并在电机发电时有效控制变流器的输出电压,着重分析了系统从起动到发电的四种状态并进行了仿真实验,结果表明该系统具有良好的性能。     

ISG系统动力部件参数设计及仿真

分析了ISG混合动力系统的结构特点和基本功能要求.在此基础上对ISG混合动力汽车动力传动系中发动机功率、电动机以及蓄电池各项参数的选择依据进行了研究;通过计算实例,在Advisor仿真软件平台上对选择的参数进行仿真,并与传统燃油汽车的仿真结果进行比较,最后证明了所选参数的合理性.     

Integrins as receptors for laminins

Laminins are a family of trimeric glycoproteins present in the extracellular matrix and the major constituents of basement membranes. Integrins are alpha beta transmembrane receptors that play critical roles in both cell-matrix and cell-cell adhesion. Several members of the integrin family, including alpha 1 beta 1, alpha 2 beta 1, alpha 3 beta 1, alpha 6 beta 1, alpha 7 beta 1 and alpha 6 beta 4 heterodimers serve as laminin receptors on a variety of cell types. This review summarizes recent advances in understanding the involvement of individual integrins in cell interactions with laminins and the roles of laminin-binding integrins in adhesion-mediated events in vertebrates, including embryonic development, cell migration and tumor cell invasiveness, cell proliferation and differentiation, as well as basement membrane assembly. We discuss the regulation of integrin function via alternative splicing of cytoplasmic domains of alpha and beta subunits of the integrin receptors for laminins and present examples of functional collaboration between laminin-binding integrins and non-integrin laminin receptors. Advances in our understanding of the laminin-binding integrins continue to demonstrate the essential roles these receptors play in maintaining cell polarity and tissue architecture.     

基于AMT的轻度混合动力系统再生制动控制

分析制动强度、ISG电动机制动力、发动机制动力以及电池充电功率的相互关系,得到电动机实际制动力随期望制动强度和车速变化曲面。提出基于电动机实际制动力的前后轮制动力分配策略。在此基础上考虑变速器挡位对传动系统工作点的影响,提出制动过程中能量最大化回收的换挡控制策略。台架试验结果表明,采用所提出的再生制动控制策略比传统控制策略能更有效地回收制动能量。     

Exosomes: Key tools for cancer liquid biopsy

Precision medicine is based on the identification of biomarkers of tumor development and progression. Liquid biopsy is at the forefront of the ability to gather diagnostic and prognostic information on tumors, as it can be noninvasively performed prior or during treatment. Liquid biopsy mostly utilizes circulating tumor cells, or free DNA, but also exosomes. The latter are nanovesicles secreted by most cell types, found in any body fluid that deliver proteins, nucleic acids and lipids to nearby and distant cells with a unique homing ability. Exosomes function in signalling between the tumor microenvironment and the rest of the body, promoting metastasis, immune remodelling and drug resistance. Exosomes are emerging as a key tool in precision medicine for cancer liquid biopsy, as they efficiently preserve their biomarker cargo. Moreover, exosomes strongly resemble the parental cell, which can help in assessing the oxidative and metabolic state of the donor cell. In this respect, exosomes represent one of the most promising new tools to fight cancer. This review will discuss the clinical applications of profiling exosomal proteins and lipids by high-throughput proteomics and metabolomics, and nucleic acids by next generation sequencing, as well as how this may allow cancer diagnosis, therapy response monitoring and recurrence detection.     

Hydrogen exchange mass spectrometry for the analysis of protein dynamics

Hydrogen exchange coupled to mass spectrometry (MS) has become a valuable analytical tool for the study of protein dynamics. By combining information about protein dynamics with more classical functional data, a more thorough understanding of protein function can be obtained. In many cases, protein dynamics are directly related to specific protein functions such as conformational changes during enzyme activation or protein movements during binding. The method is made possible because labile backbone hydrogens in a protein will exchange with deuterium atoms when the protein is placed in a D2O solution. The subsequent increase in protein mass over time is measured with high-resolution MS. The location of the deuterium incorporation is determined by monitoring deuterium incorporation in peptic fragments that are produced after the labeling reaction. In this review, we will summarize the general principles of the method, discuss the latest variations on the experimental protocol that probe different types of protein movements, and review other recent work and improvements in the field.     

Role of PTX3 and complement modulation in the tumor microenvironment

Pentraxin-3 (PTX3), the prototype of long pentraxins, seems to influence complement system (CS) modulation. PTX3 and CS sustain carcinogenesis, enriching tumor microenvironment (TME) with pro-inflammatory molecules promoting angiogenesis in prostate cancer (PC) and renal cell carcinoma (RCC). Furthermore, cancer cells overexpress complement regulatory proteins, such as CD46, CD55 and CD59, which negatively affect complement pathways for support cancer cells survival. This viewpoint aims to elucidate the ambivalent role of PTX3 and the CS in the context of tumor microenvironment (TME).     

Influence of the microenvironment on gene and protein expression of odontogenic-like and osteogenic-like cells

Progenitor cells play an important biological role in tooth and bone formation, and previous analyses during bone and dentine induction have indicated that they may be a good alternative for tissue engineering. Thus, to clarify the influence of the microenvironment on protein and gene expression, MDPC23 cells (mouse dental papilla cell line) and KUSA/A1 cells (bone marrow stromal cell line) were used, both in vitro cell culture and in intra-abdominal diffusion chambers implanted in 4-week-old male immunodefficient mice (SCID mice). Our results indicate that KUSA/A1 cells differentiated into osteoblast-like cells and induced bone tissue inside the chamber, whereas, MDPC-23 showed odontoblast-like characteristics but with a low ability to induce dentin formation. This study shows that MDPC-23 cells are especial cells, which possess morphological and functional characteristics of odontoblast-like cells expressing dentin sialophosphoprotein in vivo. In contrast, dentin sialophosphoprotein gene and protein expression was not detected in both cell lines in vitro. The intra-abdominal diffusion chamber appears as an interesting experimental model for studying phenotypic expression of dental pulp cells in vivo.     

Applications of quantitative digital image analysis to breast cancer research

Our studies of radiogenic carcinogenesis in mouse and human models of breast cancer are based on the view that cell phenotype, microenvironment composition, communication between cells and within the microenvironment are important factors in the development of breast cancer. This is complicated in the mammary gland by its postnatal development, cyclic evolution via pregnancy and involution, and dynamic remodeling of epithelial-stromal interactions, all of which contribute to breast cancer susceptibility. Microscopy is the tool of choice to examine cells in context. Specific features can be defined using probes, antibodies, immunofluorescence, and image analysis to measure protein distribution, cell composition, and genomic instability in human and mouse models of breast cancer. We discuss the integration of image acquisition, analysis, and annotation to efficiently analyze large amounts of image data. In the future, cell and tissue image-based studies will be facilitated by a bioinformatics strategy that generates multidimensional databases of quantitative information derived from molecular, immunological, and morphological probes at multiple resolutions. This approach will facilitate the construction of an in vivo phenotype database necessary for understanding when, where, and how normal cells become cancer.     

轻度混合动力AMT汽车自动起步控制研究

利用ISG(integrated starter/generator)电机的助力功能,在车辆起步时辅助发动机工作,将动力源(发动机和ISG电机)转速维持在较低范围内,使车辆迅速平稳起步,大大减少了离合器的滑摩功.在建立轻度混合动力AMT汽车起步模型的基础上进行了仿真,并提出了车辆自动起步控制规律.     

电动车辆ISG电机全性能检测台架研制

基于交流电机拖动/加载技术,通过整流/逆变一体化的高性能电源并整合测试仪器,研制了电动车辆用ISG系统的稳态和动态性能测试台架。利用PC控制和测试软件,该台架能够实时地对测试数据进行存储和显示,其动态性能良好。台架实现了基于同一平台的包括电机电驱动和发电特性的测试要求,节约了测试时间和测试成本。基于该台架完成了十余套电动车辆用电机的测试试验工作。     

Prognostic tumor microenvironment gene and the relationship with immune infiltration characteristics in metastatic breast cancer

The aim of this study was to reveal genes associated with breast cancer metastasis, to investigate their intrinsic relationship with immune cell infiltration in the tumor microenvironment, and to screen for prognostic biomarkers. Gene expression data of breast cancer patients and their metastases were downloaded from the GEO, TCGA database. R language package was used to screen for differentially expressed genes, enrichment analysis of genes, PPI network construction, and also to elucidate key genes for diagnostic and prognostic survival. Spearman’s r correlation was used to analyze the correlation between key genes and infiltrating immune cells. We screened 25 hub genes, FN1, CLEC5A, ATP8B4, TLR7, LY86, PTGER3 and other genes were differentially expressed in cancer and paraneoplastic tissues. However, patients with higher expression of CD1C, IL-18 breast cancer had a better prognosis in the 10 years survival period, while patients with high expression of FN1, EIF4EBP1 tumors had a worse prognosis. In addition, TP53 and HIF1 genes are closely related to the signaling pathway of breast cancer metastasis. In this study, gene expression of ATP8B4 and CD1C were correlated with cancer tissue infiltration of CD8⁺ T lymphocytes, while GSE43816, GSE62327 and TCGA databases showed that CD8⁺ T lymphocytes were closely associated with breast cancer progression. Functional enrichment analysis of genes based on expression differences yielded key genes of prognostic value in the breast cancer microenvironment.