富亮氨酸α2糖蛋白1(LRG1)在肿瘤中的研究进展

富亮氨酸α2糖蛋白1(Leucine-rich-alpha-2-glycoprotein1,LRG1)是富亮氨酸重复序列(leucine-rich repeat,LRR)家族蛋白成员之一。LRG1在人类多种肿瘤中表达异常,可以作为部分肿瘤早期诊断的潜在生物标记,而且这种异常表达可能提示患者预后不良。LRG1在肿瘤的发生、侵袭转移、上皮间质转化和血管生成中发挥重要作用。这些环节中,协同参与调控的辅助因子众多且有差异,因而经历的信号途径有所不同。本文综合目前的研究进展,旨在阐述LRG1与肿瘤的关系以及其调控肿瘤发生发展的分子机制。LRG1有望成为一种新的肿瘤分子标志物,将为恶性肿瘤的分子诊断及靶向治疗提供新的方向和手段。     

ANGPTL3与代谢紊乱相关疾病的研究进展

血管生成素样蛋白3(ANGPTL3)是一种分泌性糖蛋白,与家族性低β脂蛋白血症、动脉粥样硬化、糖尿病等代谢紊乱疾病的发生密切相关。ANGPTL3具有调控脂质代谢和促进血管生成的功能,研究ANGPTL3与代谢紊乱相关疾病的关系,对防治相关疾病具有重要意义。     

富亮氨酸alpha2 糖蛋白1（LRG1）在肿瘤中的研究进展

富亮氨酸琢2 糖蛋白1(Leucine-rich-alpha-2-glycoprotein1,LRG1）是富亮氨酸重复序列(leucine-rich repeat, LRR)家族蛋白成 员之一。LRG1 在人类多种肿瘤中表达异常,可以作为部分肿瘤早期诊断的潜在生物标记,而且这种异常表达可能提示患者预后 不良。LRG1 在肿瘤的发生、侵袭转移、上皮间质转化和血管生成中发挥重要作用。这些环节中,协同参与调控的辅助因子众多且 有差异,因而经历的信号途径有所不同。本文综合目前的研究进展,旨在阐述LRG1 与肿瘤的关系以及其调控肿瘤发生发展的分 子机制。LRG1 有望成为一种新的肿瘤分子标志物,将为恶性肿瘤的分子诊断及靶向治疗提供新的方向和手段。     

利用条件基因沉默系统研究CHIP对TGF-β信号通路的调控

根据条件基因敲除技术和基因沉默的理论,构建了可被CRE操控的条件基因沉默系统,并应用其研究分子伴侣相互作用蛋白CHIP(C-terminus of Hsc70-interacting protein)对TGF-β信号通路的调控．RT-PCR和免疫印迹结果显示,pLoxP/CHIPi与CRE相互作用后,可以有效地降低内源CHIP的mRNA水平,减少外源和内源CHIP的蛋白质量．荧光素酶报告系统分析表明,条件基因沉默能解除CHIP对TGF-β信号通路的抑制性调控,增强TGF-β信号通路的转录活性．结果表明,CRE依赖的条件基因沉默系统具有高效性、特异性,并通过它反向验证了CHIP对TGF-β信号通路的抑制性调控,为进一步研究与CHIP相关的TGF-β信号通路所致疾病的发生机理提供了有效工具．     

蛋白质内稳态质控因子CHIP的研究进展

机体各项生命活动的进行有赖于细胞内蛋白质内稳态的维持。热休克蛋白70羧基端作用蛋白(carboxyterminus of Hsp70 interacting protein, CHIP)作为E3泛素连接酶,是蛋白质量控制系统的重要元件,可与热休克蛋白(heat shock proteins, Hsps)家族共调蛋白折叠及降解平衡,也可通过自噬途径或发挥分子伴侣功能使机体适应蛋白质毒性压力。由于CHIP的靶蛋白,如突变p53(mutant-type p53, mutp53)多与重大生物学事件相关,甚至影响肿瘤、心脏病等疾病的发生发展。因此,深入研究CHIP调节蛋白质内稳态的机制及其对疾病进程的影响,可为蛋白质代谢紊乱相关疾病的防控治疗提供理论基础。     

转化生长因子β调节血管平滑肌细胞分化和表型转换的研究进展

转化生长因子β(TGF-β)超家族是一类分泌型多肽信号分子,在调节细胞生长、分化、凋亡和组织稳态方面具有重要功能。对于血管平滑肌细胞,TGF-β可以促进前体细胞向平滑肌细胞分化和维持平滑肌细胞的收缩表型;TGF-β信号通路异常可以引起家族性动脉瘤,如Marfan综合征和Loeys-Dietz综合征等。我们简要综述了TGF-β在调节血管平滑肌细胞分化和表型转换过程中的分子机制研究进展,以及TGF-β调节的平滑肌细胞分化和表型转换异常在动脉瘤中的作用。     

利用四环素调控系统研究 CHIP 对TGF-β信号通路的抑制性调节

为了研究伴侣分子相互作用蛋白 CHIP 对 TGF-β信号通路的调控,利用四环素基因表达调控系统,建立四环素调控表达 CHIP 的稳定细胞系 (Mv1Lu-Tet off-CHIP). 利用此细胞模型,发现 CHIP 的过量表达可显著降低细胞内 Smad2/3 蛋白水平;荧光素酶报告分析也表明开启 CHIP 蛋白表达可明显降低 Smads 介导的基因转录活性;进一步的免疫印迹结果显示 CHIP 蛋白可明显下调 TGF-β所诱导的下游基因 JunB 的表达 . 上述结果提示 CHIP 可以作为一种新的蛋白质分子抑制性调节 TGF-β信号通路 .     

内皮细胞代谢在血管新生中的作用研究

血管生成是指从已有的毛细血管或毛细血管后静脉发展而形成新血管的过程。血管生成调控过程复杂,交错影响,多种基因和信号分子如血管内皮生长因子(vascular endothelial growth factor, VEGF)家族、纤维母细胞生长因子(fibroblast growth factor, FGF)家族、Notch和Wnt信号通路、转化生长因子-β(transforming growth factor-β, TGF-β)信号、血管生成素(angiotensin, Ang)和Tie信号系统等参与调控血管生成。除了遗传和分子信号外,血管生成还受到代谢机制的调节。在此,本文概述了目前对内皮细胞(endothelial cells, ECs)各种代谢途径的认识及其对生理和病理性血管生成的影响。其中,糖酵解、脂肪酸氧化和氨基酸代谢是目前最为常见的代谢途径,ECs主要依靠糖酵解产生ATP。糖酵解调节器6-磷酸果糖激酶-2/2,6-二磷酸果糖激酶3 (6-phosphofructo-2-kinase/fructose-2,6-diphosphatase 3, PFKFB3)通过调控尖端细胞(T...     

14-3-3蛋白研究进展

14-3-3蛋白是高度保守的、所有真核生物细胞中都普遍存在的、在大多数生物物种中由一个基因家族编码的一类蛋白调控家族。它几乎参与生命体所有的生理反应过程,人们在各种组织细胞中发现了各种不同的14-3-3蛋白。作为与磷酸丝氨酸／苏氨酸结合的第一信号分子,14-3-3蛋白在细胞的信号转导中起着至关重要的作用,尤其是它直接参与调节蛋白激酶和蛋白磷酸化酶的活性,被称为蛋白质与蛋白质相互作用的”桥梁蛋白”;它可以与转录因子结合形成复合体,调节相关基因的表达。一些研究表明,14-3-3蛋白调控机制的紊乱可以直接导致疾病的发生,在临床上14-3-3蛋白常常可以作为诊断的标志物。     

舌的发育及其调控机制

舌是参与咀嚼、吸允、吞咽、发音等功能的重要器官。舌发育异常会导致无舌、小舌、舌裂、结舌、巨舌症、腭裂等严重的先天舌发育缺陷疾病。发育完全的舌由肌肉组织、结缔组织、黏膜组织及血管组成。调控舌发育的基因有Pax3/Pax7、Dlx基因家族、TGF-β家族和FGF等,同时还受Shh与Wnt等信号通路调控。舌发育分子调控机制的研究对相关舌发育畸形疾病的诊断与治疗有重要意义。     

VEGF and PlGF: two pleiotropic growth factors with distinct roles in development and homeostasis

Blood vessels are crucial for normal development and growth by providing oxygen and nutrients. As shown by genetic targeting studies in mice, zebrafish and Xenopus blood vessel formation (or angiogenesis) is a multistep process, which is highly dependent on angiogenic growth factors such as VEGF, the founding member of the VEGF family. VEGF binds to the tyrosine kinase receptors VEGFR-1 and VEGFR-2, and loss of VEGF or its receptors results in abnormal angiogenesis and lethality during development. In contrast, PlGF, another member of this family, binds only to VEGFR-1, and appears to be crucial exclusively for pathological angiogenesis in the adult. However, the expression of VEGFR-1 and VEGFR-2 on non-vascular cells suggests additional biological properties for these growth factors. Indeed, the VEGF family and its receptors determine development and homeostasis of many organs, including the respiratory, skeletal, hematopoietic, nervous, renal and reproductive system, independent of their vascular role. These new insights broaden the activity spectrum of these "angiogenic" growth factors, and may have therapeutic implications when using these growth factors for vascular and/or non-vascular purposes.     

TGF-β singaling and cancer: structural and functional consequences of mutations in Smads

Transforming growth factor-β (TGF-β) and related cytokines control the development and homeostasis of many tissues by regulating the expression of genes that determine cell phenotype. Recent progress has elucidated the way in which members of the TGF-β family initiate their signal through transmembrane receptors and transmit it to target genes via the Smad family of signal-transducing proteins. This review describes TGF-β signaling pathways as currently understood and mutations of the genes that encode Smads that disrupt the function of these proteins and cause various forms of cancer.     

Angiogenesis inhibitors found within the haemostasis pathway

Angiogenesis, the development of new blood vessels from the existing vasculature, and haemostasis, the coagulation cascade leading to formation of a clot, are among the most consistent host responses associated with cancer. Importantly, these two pathways interrelate, with blood coagulation and fibrinolysis influencing tumor angiogenesis directly, thereby contributing to tumor growth. Moreover, many endogenous inhibitors of angiogenesis are found within platelets or harboured as cryptic fragments of haemostatic proteins. In this review we outline ways in which angiogenesis is coordinated and regulated by haemostasis in human cancer. Then we detail the experimental and pre-clinical evidence for the ability of many of these endogenous proteins to inhibit tumor angiogenesis and thus their potential to be anti-cancer agents, with particular reference to any clinical trials.     

ENDOGLIN Is Dispensable for Vasculogenesis,but Required for Vascular Endothelial Growth Factor-Induced Angiogenesis

ENDOGLIN (ENG) is a co-receptor for transforming growth factor-β (TGF-β) family members that is highly expressed in endothelial cells and has a critical function in the development of the vascular system. Mutations in Eng are associated with the vascular disease known as hereditary hemorrhagic telangiectasia type l. Using mouse embryonic stem cells we observed that angiogenic factors, including vascular endothelial growth factor (VEGF), induce vasculogenesis in embryoid bodies even when Eng deficient cells or cells depleted of Eng using shRNA are used. However, ENG is required for the stem cell-derived endothelial cells to organize effectively into tubular structures. Consistent with this finding, fetal metatarsals isolated from E17.5 Eng heterozygous mouse embryos showed reduced VEGF-induced vascular network formation. Moreover, shRNA-mediated depletion and pharmacological inhibition of ENG in human umbilical vein cells mitigated VEGF-induced angiogenesis. In summary, we demonstrate that ENG is required for efficient VEGF-induced angiogenesis.     

The regulatory mechanism of Hsp90α secretion from endothelial cells and its role in angiogenesis during wound healing

Heat shock protein 90α (Hsp90α) is a ubiquitously expressed molecular chaperone, which is essential for the maintenance of eukaryote homeostasis. Hsp90α can also be secreted extracellularly and is associated with several physiological and pathological processes including wound healing, cancer, infectious diseases and diabetes. Angiogenesis, defined as the sprouting of new blood vessels from pre-existing capillaries via endothelial cell proliferation and migration, commonly occurs in and contributes to the above mentioned processes. However, the secretion of Hsp90α from endothelial cells and also its function in angiogenesis are still unclear. Here we investigated the role of extracellular Hsp90α in angiogenesis using dermal endothelial cells in vitro and a wound healing model in vivo. We find that the secretion of Hsp90α but not Hsp90β is increased in activated endothelial cells with the induction of angiogenic factors and matrix proteins. Secreted Hsp90α localizes on the leading edge of endothelial cells and promotes their angiogenic activities, whereas Hsp90α neutralizing antibodies reverse the effect. Furthermore, using a mouse skin wound healing model in vivo, we demonstrate that extracellular Hsp90α localizes on blood vessels in granulation tissues of wounded skin and promotes angiogenesis during wound healing. Taken together, our study reveals that Hsp90α can be secreted by activated endothelial cells and is a positive regulator of angiogenesis, suggesting the potential application of Hsp90α as a stimulator for wound repair.     

Betaglycan knock‐down causes embryonic angiogenesis defects in zebrafish

Angiogenesis is an essential requirement for embryonic development and adult homeostasis. Its deregulation is a key feature of numerous pathologies and many studies have shown that members of the transforming growth factor beta (TGF‐β) family of proteins play important roles in angiogenesis during development and disease. Betaglycan (BG), also known as TGF‐β receptor type III, is a TGF‐β coreceptor essential for mice embryonic development but its role in angiogenesis has not been described. We have cloned the cDNA encoding zebrafish BG, a TGF‐β‐binding membrane proteoglycan that showed a dynamic expression pattern in zebrafish embryos, including the notochord and cells adjacent to developing vessels. Injection of antisense morpholinos decreased BG protein levels and morphant embryos exhibited impaired angiogenesis that was rescued by coinjection with rat BG mRNA. In vivo time‐lapse microscopy revealed that BG deficiency differentially affected arterial and venous angiogenesis: morphants showed impaired pathfinding of intersegmental vessels migrating from dorsal aorta, while endothelial cells originating from the caudal vein displayed sprouting and migration defects. Our results reveal a new role for BG during embryonic angiogenesis in zebrafish, which has not been described in mammals and pose interesting questions about the molecular machinery regulating angiogenesis in different vertebrates. genesis 53:583–603, 2015. © 2015 Wiley Periodicals, Inc.     

SSeCKS regulates angiogenesis and tight junction formation in blood-brain barrier

The blood-brain barrier (BBB) is essential for maintaining brain homeostasis and low permeability. BBB maintenance is important in the central nervous system (CNS) because disruption of the BBB may contribute to many brain disorders, including Alzheimer disease and ischemic stroke. The molecular mechanisms of BBB development remain ill-defined, however. Here we report that src-suppressed C-kinase substrate (SSeCKS) decreases the expression of vascular endothelial growth factor (VEGF) through AP-1 reduction and stimulates expression of angiopoietin-1 (Ang-1), an antipermeability factor in astrocytes. Conditioned media from SSeCKS-overexpressing astrocytes (SSeCKS-CM) blocked angiogenesis in vivo and in vitro. Moreover, SSeCKS-CM increased tight junction proteins in endothelial cells, consequently decreasing [3H]sucrose permeability. Furthermore, immunoreactivity to SSeCKS gradually increased during the BBB maturation period, and SSeCKS-expressing astrocytes closely interacted with zonula occludens (ZO)-1-expressing blood vessels in vivo. Collectively, our results suggest that SSeCKS regulates BBB differentiation by modulating both brain angiogenesis and tight junction formation.     

The angiogenic effects of exosomes secreted from retinal pigment epithelial cells on endothelial cells

Exosomes are informative microvesicles associated with intercellular communication via the transfer of many molecular constituents such as proteins, lipids, and nucleic acids; environmental changes and the cellular status around cells greatly affect exosome components. Cells of the retinal pigment epithelium (RPE) are key players in retinal homeostasis. Transforming growth factor (TGF)-β and tumour necrosis factor (TNF)-α are increased in the vitreous and retina in several retinal diseases and activate and undergo epithelial-mesenchymal transition (EMT) in RPE cells. EMT is closely associated with mechanisms of wound healing, including fibrosis and related angiogenesis; however, whether exosome components depend on the cell status, epithelium or mesenchyme and whether these exosomes have pro- or anti-angiogenic roles in the retina are unknown. We performed this study to investigate whether these EMT inducers affect the kinds of components in exosomes secreted from RPE cells and to assess their angiogenic effects. Exosomes were collected from culture media supernatants of a human RPE cell line (ARPE-19) stimulated with or without 10 ng/ml TNF-α and/or 5 ng/ml TGF-β2. NanoSight tracking analysis and immunoblot analysis using exosome markers were used to qualify harvested vesicles. Angiogenic factor microarray analysis revealed that exosomes derived from ARPE-19 cells cultured with TNF-α alone (Exo-TNF) and co-stimulated with TNF-α and TGF-β2 (Exo-CO) contained more angiogenic factors than exosomes derived from control cells (Exo-CTL) or ARPE-19 cells cultured with TGF-β2 alone (Exo-TGF). To assess the effect on angiogenesis, we performed chemotaxis, tube formation, and proliferation assays of human umbilical vein endothelial cells (HUVECs) stimulated with or without exosomes. HUVECs migrated to RPE-derived exosomes, and exosomes derived from ARPE-19 cells accelerated HUVEC tube formation. In contrast, Exo-TNF and Exo-CO reduced HUVEC proliferation. Our findings provide insight into the mechanisms underlying the relation between angiogenesis and exosomes derived from RPE cells.     

The ALK-1/Smad1 pathway in cardiovascular physiopathology. A new target for therapy?

Activin receptor-like kinase-1 or ALK-1 is a type I cell surface receptor for the transforming growth factor-β (TGF-β) family of proteins. The role of ALK-1 in endothelial cells biology and in angiogenesis has been thoroughly studied by many authors. However, it has been recently suggested a possible role of ALK-1 in cardiovascular homeostasis.ALK-1 is not only expressed in endothelial cells but also in smooth muscle cells, myofibroblast, hepatic stellate cells, chondrocytes, monocytes, myoblasts, macrophages or fibroblasts, but its role in these cells have not been deeply analyzed. Due to the function of ALK-1 in these cells, this receptor plays a role in several cardiovascular diseases. Animals with ALK-1 haploinsufficiency and patients with mutations in Acvrl1 (the gene that codifies for ALK-1) develop type-2 Hereditary Hemorrhagic Telangiectasia. Moreover, ALK-1 heterozygous mice develop pulmonary hypertension. Higher levels of ALK-1 have been observed in atherosclerotic plaques, suggesting a possible protector role of this receptor. ALK-1 deficiency is also related to the development of arteriovenous malformations (AVMs). Besides, due to the ability of ALK-1 to regulate cell proliferation and migration, and to modulate extracellular matrix (ECM) protein expression in several cell types, ALK-1 has been now demonstrated to play an important role in cardiovascular remodeling.In this review, we would like to offer a complete vision of the role of ALK-1 in many process related to cardiovascular homeostasis, and the involvement of this protein in the development of cardiovascular diseases, suggesting the possibility of using the ALK-1/smad-1 pathway as a powerful therapeutic target.     

Glioma angiogenesis: Towards novel RNA therapeutics

Brain tumors exhibit marked and aberrant blood vessel formation indicating angiogenic endothelial cells as a potential target for brain tumor treatment. The brain tumor blood vessels are used for nutrient delivery, and possibly for cancer cell migration. The process of angiogenesis is complex and involves multiple players. The current angiogenesis inhibitors used in clinical trials mostly target single angiogenic proteins and so far show limited effects on tumor growth. Besides the conventional angiogenesis inhibitors, RNA-based inhibitors such as small-interfering RNAs (siRNAs) are being analyzed for their capacity to silence the message of proteins involved in neovascularization. More recently, a new family of non-coding RNAs, named angiomirs [microRNAs (miRNAs) involved in angiogenesis] has emerged. These small RNAs have the advantage over siRNAs in that they have the potential of silencing multiple messages at the same time and therefore they might become therapeutically relevant in a “one-hit multiple-target” context against brain tumor angiogenesis. In this review we will discuss the emerging technologies in anti-angiogenesis emphasizing on RNA-based therapeutics.Key words: glioma, angiogenesis, anti-angiogenesis therapy, siRNA, miRNA, endothelial cells, blood vessels