Role of activin receptor-like kinase 1 in vascular development and cerebrovascular diseases

Activin receptor-like kinase 1(ALK1)is a transmembrane serine/threonine receptor kinase of the transforming growth factor beta(TGFβ)receptor superfamily.ALK1 is specifically expressed in vascular endothelial cells,and its dynamic changes are closely related to the proliferation of endothelial cells,the recruitment of pericytes to blood vessels,and functional differentiation during embryonic vascular development.The pathophysiology of many cerebrovascular diseases is today understood as a disorder of endothelial cell function and an imbalance in the proportion of vascular cells.Indeed,mutations in ALK1 and its co-receptor endoglin are major genetic risk factors for vascular arteriovenous malformation.Many studies have shown that ALK1 is closely related to the development of cerebral aneurysms,arteriovenous malformations,and cerebral atherosclerosis.In this review,we describe the various roles of ALK1 in the regulation of angiogenesis and in the maintenance of cerebral vascular homeostasis,and we discuss its relationship to functional dysregulation in cerebrovascular diseases.This review should provide new perspectives for basic research on cerebrovascular diseases and offer more effective targets and strategies for clinical diagnosis,treatment,and prevention.

The PtoTCP20-miR396d-PtoGRF15 module regulates secondary vascular development in Populus

Secondary vascular development is a key biological characteristic of woody plants and the basis of wood formation.Our understanding of gene expression regulation and dynamic changes in microRNAs(miRNAs)during secondary vascular development is still limited.Here we present an integrated analysis of the miRNA and mRNA transcriptome of six phase-specific tissues-the shoot apex,procambium,primary vascular tissue,cambium,secondary phloem,and secondary xylem-in Populus tomentosa.Several novel regulatory modules,including the PtoTCP20-miR396d-PtoGRF15 module,were identified during secondary vascular development in Populus.A series of biochemical and molecular experiments confirmed that PtoTCP20 activated transcription of the miR396d precursor gene and that miR396d targeted PtoGRF15 to downregulate its expression.Plants overexpressing miR396d(35S:miR396d)showed enhanced secondary growth and increased xylem production.Conversely,during the transition from primary to secondary vascular development,plants with downregulated PtoTCP20expression(PtoTCP20-SRDX),downregulated miR396 expression(35S:STTM396),and PtoGRF15 overexpression(35S:PtoGRF15)showed delayed secondary growth.Novel regulatory modules were identified by integrated analysis of the miRNA and mRNA transcriptome,and the regulatory role of the PtoTCP20-miR396d-PtoGRF15 signaling cascade in secondary vascular development was validated in Populus,providing information to support improvements in forest cultivation and wood properties.

Identification and Validation of Vascular-Associated Biomarkers for the Prognosis and Potential Pathogenesis of Hypertension Using Comprehensive Bioinformatics Methods

Background: Hypertension, also known as increased blood pressure, is a phenomenon in which blood flows in blood vessels and causes persistently higher-than-normal pressure on the vessel wall. The identification of novel prognostic and pathogenesis biomarkers plays a key role in the management of hypertension. Methods: The GSE7483 and GSE75815 datasets from the gene expression omnibus (GEO) database were used to identify the genes associated with hypertension that were differentially expressed genes (DEGs). The functional role of the DEGs was elucidated by gene body (GO) enrichment analysis. In addition, we performed an immune infiltration assay and GSEA on the DEGs of hypertensive patients and verified the expression of novel DEGs in the blood of hypertensive patients by RT-qPCR. Results: A total of 267 DEGs were identified from the GEO database. GO analysis revealed that these genes were associated mainly with biological processes such as fibroblast proliferation, cell structural organization, extracellular matrix organization, vasculature development regulation, and angiogenesis. We identified five possible biomarkers, Ecm1, Sparc, Sphk1, Thbsl, and Mecp2, which correlate with vascular development and angiogenesis characteristic of hypertension by bioinformatics, and explored the clinical expression levels of these genes by RT-qPCR, and found that Sparc, Sphk1, and Thbs1 showed significant up-regulation, in agreement with the results of the bioinformatics analysis. Conclusion: Our study suggested that Sparc, Sphk1 and Thbs1 may be potential novel biomarkers for the diagnosis, treatment and prognosis of hypertension and that they are involved in the regulation of vascular development and angiogenesis in hypertension.

SERK Family Receptor-like Kinases Function as Co-receptors with PXY for Plant Vascular Development

In Arabidopsis, the CLAVATA3/EMBRYO SURROUNDING REGION-RELATED （CLE） peptides play important roles in regulating proliferation and differentiation of plant-specific stem cells. Although receptors of CLEs are reported to be leucine-rich repeat receptor kinases, the mechanisms underlying CLE-induced receptor activation remain largely unknown. Here we show that SOMATIC EMBRYOGENESIS RECEPTOR KINASEs （SERKs） serve as co-receptors in CLE41/TDIF-PXY signaling to regulate plant vascular development. TDIF induces interaction of its receptor PXY with SERKs in vitro and in vivo. Furthermore, the serk1-1 serk2-1 bakl-5 mutant plants are less sensitive to TDIF, phenocopying the pxy mutant with a compromised promotion of procambial cell proliferation. Crystal structure of the PXY-TDIF-SERK2 complex reveals that the last amino acid of TDIF conserved among CLEs and other evolutionary-related peptides is important for the interaction between SERK2 and PXY. Taken together, our current study identifies SERKs as signaling components of the TDIF-PXY pathway and suggests a conserved activation mechanism of CLE receptors.

Regulation of Vascular Development by CLE Peptide-receptor Systems

Cell division and differentiation of stem cells are controlled by non- cell-autonomous signals in higher organisms. The plant vascular meristem is a stem-cell tissue comprising procambial cells that produce xylem cells on one side and phloem cells on the other side. Recent studies have revealed that TDIF （tracheary element differentiation inhibitory factor）/CLE41/CLE44 peptide signal controls the procambial cell fate in a non-cell-autonomous manner. TDIF produced in and secreted from phloem cells is perceived by TDR/PXY, a leucine-rich repeat receptor kinase located in the plasma membrane of procambial cells. This signal suppresses xylem cell differentiation of procambial cells and promotes their proliferation. In addition to TDIF, some other CLE peptides play roles in vascular development. Here, we summarize recent advances in CLE signaling governing vascular development.

Emerging roles of podoplanin in vascular development and homeostasis

Podoplanin （PDPN） is a mucin-type O-glycoprotein expressed in diverse cell types, such as lymphatic endothelial cells （LECs） in the vascular system and fibroblastic reticular cells （FRCs） in lymph nodes. PDPN on LECs or FRCs activates CLEC-2 in platelets, triggering platelet activation and/or aggregation through downstream signaling events, including activation of Syk kinase. This mechanism is required to initiate and maintain separation of blood and lymphatic vessels and to stabilize high endothelial venule integrity within lymph nodes. In the vascular system, normal expression of PDPN at the LEC surface requires transcriptional activation of Pdpn by Proxl and modification of PDPN with core 1-derived O-glycans. This review provides a comprehensive overview of the roles of PDPN in vascular development and lymphoid organ maintenance and discusses the mechanisms that regulate PDPN expression related to its function.

CLE Peptides in Vascular Development

The plant vascular system consists of two conductive tissues, phloem and xylem. The vascular meristem, namely the （pro-）cambium, is a stem- cell tissue that gives rise to both xylem and phloem. Recent studies have revealed that CLAVATA3/Embryo Surrounding Region-related （CLE） pep- tides function in establishing the vascular system through interaction with phytohormones. In particular, TDIF/CLE41/CLE44, phloem-derived CLE peptides, promote the proliferation of vascular cambium cells and prevent them from differentiating into xylem by regulating WOX4 expres- sion through the TDR/PXY receptor. In this review article, we outline recent advances on how CLE peptides function in vascular developmentin concert with phytohormones through mediating cell-cell communication. The perspective of CLE peptide signaling in vascular development is also discussed.

AB002. Guidance of vascular patterning in ocular development and disease

Ocular vessel networks develop in a highly stereotyped fashion.Abnormal ocular angiogenesis is associated with major diseases including age-related macular degeneration and diabetic retinopathy.Better understanding of mechanisms driving angiogenesis is expected to uncover novel targets to prevent vision loss.Capillary growth is driven by endothelial tip cells,which are selected by dynamic interplay between VEGF,Notch and BMP signaling,with VEGF acting as a positive regulator,and Notch and the BMP receptor Alk1 acting as negative regulators of tip cell formation.The concerted interplay between these molecules ensures that appropriate tip cell numbers leading new vessel branches are formed.In addition,guidance receptors including Neuropilins and Roundabout receptors contribute to vascular patterning by regulating VEGF and BMP signaling.Possibilities to target these pathways during pathological ocular neovascularization will be discussed.

ANAC005 is a membrane-associated transcription factor and regulates vascular development in Arabidopsis

Vascular tissues are very important for providing both mechanical strength and long-distance transport. The molecular mechanisms of regulation of vascular tissue develop- ment are still not fully understood. In this study we identified ANACoo5 as a membrane-associated NAC family transcription factor that regulates vascular tissue development. Reporter gene assays showed that ANACoo5 was expressed mainly in the vascular tissues, increased expression of ANACoo5 protein in transgenic Arabidopsis caused dwarf phenotype, reduced xylem differentiation, decreased lignin content, repression of a lignin biosynthetic gene and genes related to cambium and primary wall, but activation of genes related to the secondary wall. Expression of a dominant repressor fusion of ANACoo5 had overall the opposite effects on vascular tissue differ- entiation and lignin synthetic gene expression. The ANACoo5- GFP fusion protein was localized at the plasma membrane, whereas deletion of the last 20 amino acids, which are mostly basic, caused its nuclear localization. These results indicate that ANACoo5 is a cell membrane-associated transcription factor that inhibits xylem tissue development in Arabidopsis.

Effects of long non-coding RNA myocardial infarction-associated transcript on retinal neovascularization in a newborn mouse model of oxygen-induced retinopathy

Whether long non-coding RNA myocardial infarction-associated transcript is involved in oxygen-induced retinopathy remains poorly understood. To validate this hypothesis, we established a newborn mouse model of oxygen-induced retinopathy by feeding in an oxygen concentration of 75 ± 2% from postnatal day 8 to postnatal day 12, followed by in normal air. On postnatal day 11, the mice were injected with the myocardial infarction-associated transcript siRNA plasmid via the vitreous cavity to knockdown long non-coding RNA myocardial infarction-associated transcript. Myocardial infarction-associated transcript siRNA transcription significantly inhibited myocardial infarctionassociated transcript mRNA expression, reduced the phosphatidylinosital-3-kinase, phosphorylated Akt and vascular endothelial growth factor immunopositivities, protein and mRNA expression, and alleviated the pathological damage to the retina of oxygen-induced retinopathy mouse models. These findings suggest that myocardial infarction-associated transcript is likely involved in the retinal neovascularization in retinopathy of prematurity and that inhibition of myocardial infarction-associated transcript can downregulate phosphatidylinosital-3-kinase, phosphorylated Akt and vascular endothelial growth factor expression levels and inhibit neovascularization. This study was approved by the Animal Ethics Committee of Shengjing Hospital of China Medical University, China(approval No. 2016 PS074 K) on February 25, 2016.

Role of Axonal Guidance Factor Netrin-1 in Human Placental Vascular Growth

This study investigated the role of netrin-1 in placental vascular development. In vitro rat aortic ring assay and in vivo Matrigel plug assay were conducted to exmaine the effect of netrin-1 on angiogenesis. Human placental microvascular endothelial cells （HPMECs） were isolated and cultured and their viability, migration and tubular formation were studied, in order to examine the effects of netrin-1. The results showed that netrin-1 potently stimulated neovascularization in a mouse Matrigel plug in vivo and the sprouting of endothelial cells in rat aortic rings in vitro. In addition, netrin-1 enhanced the viability, migration and tube formation of HPMECs. Our study suggested that netrin-1 could significantly promote the formation of blood vessels of human placenta and may be a potential target for developing new therapeutic strategies for placental vasculature-related diseases.

Hexafluoropropylene oxide trimer acid,a perfluorooctanoic acid alternative,induces cardiovascular toxicity in zebrafish embryos

As an increasingly used alternative to perfluorooctanoic acid(PFOA),hexafluoropropylene oxide trimer acid(HFPO-TA)has been widely detected in global water environments.However,little is known regarding its toxic effects on cardiovascular development.Here,zebrafish embryos were treated with egg water containing 0,60,120,or 240 mg/L HFPO-TA.Results showed that HFPO-TA treatment led to a significant reduction in both larval survival percentage and heart rate.Furthermore,HFPO-TA exposure caused severe pericardial edema and elongation of the sinus venous to bulbus arteriosus distance(SV-BA)in Tg(myl7:GFP)transgenic larvae,disrupting the expression of genes involved in heart development and thus causing abnormal heart looping.Obvious sprouting angiogenesis was observed in the 120 and 240 mg/L exposed Tg(fli:GFP)transgenic larvae.HFPO-TA treatment also impacted the mRNA levels of genes involved in the vascular endothelial growth factor(VEGF)pathway and embryonic vascular development.HFPO-TA exposure significantly decreased erythrocyte number in Tg(gata1:DsRed)transgenic embryos and influenced gene expression associated with the heme metabolism pathway.HFPO-TA also induced oxidative stress and altered the transcriptional levels of genes related to cell cycle and apoptosis,inhibiting cell proliferation while promoting apoptosis.Therefore,HFPO-TA exposure may induce abnormal development of the cardiovascular and hematopoietic systems in zebrafish embryos,suggesting it may not be a suitable or safe alternative for PFOA.

The Plant Vascular System: Evolution, Development and Functions

The emergence of the tracheophyte-based vascular system of land plants had major impacts on the evolution of terrestrial biology, in general, through its role in facilitating the development of plants with increased stature, photosynthetic output, and ability to colonize a greatly expanded range of environmental habitats. Recently, considerable progress has been made in terms of our understanding of the developmental and physiological programs involved in the formation and function of the plant vascular system. In this review, we first examine the evolutionary events that gave rise to the tracheophytes, followed by analysis of the genetic and hormonal networks that cooperate to orchestrate vascular development in the gymnosperms and angiosperms. The two essentialfunctions performed by the vascular system, namely the delivery of resources （water, essential mineral nutrients, sugars and amino acids） to the various plant organs and provision of mechanical support are next discussed. Here, we focus on critical questions relating to structural and physiological properties controlling the delivery of material through the xylem and phloem. Recent discoveries into the role of the vascular system as an effective long-distance communication system are next assessed in terms of the coordination of developmental, physiological and defense-related processes, at the whole-plant level. A concerted effort has been made to integrate all these new findings into a comprehensive picture of the state-of-the-art in the area of plant vascular biology. Finally, areas important for future research are highlighted in terms of their likely contribution both to basic knowledge and applications to primary industry.

脑发育性静脉异常的影像学诊断

目的:分析脑发育性静脉异常的CT、MRI和DSA表现,提高对本病的认识。方法:17例脑发育性静脉异常(DVA)患者中15例行MRI检查、CT检查6例、DSA检查4例。对DVA在不同影像检查的表现进行分析,对DVA的部位、分型、引流方式以及合并的其它异常进行探讨。结果:17例患者有21个DVA,其中3例多发,4例患者合并有海绵状血管瘤。21个DVA中幕上7个,幕下14个,根据其位置分为浅型(皮层和皮层下区)12个和深型9个,其引流静脉中单支引流14例,多支引流3例。增强CT、增强MRI和DSA静脉期均能清晰显示其特征性表现既"水母头"状扩张的髓静脉汇入粗大的引流静脉干。结论:增强CT、MRI以及DSA检查均能正确诊断和评价DVA,DSA是诊断DVA并与其它血管畸形鉴别的金标准;多种序列组合使MRI能更全面的评价DVA及其合并的其它脑实质异常,是DVA检查的首选方法。

脑发育性静脉异常的CT诊断

目的分析脑发育性静脉异常的CT表现,评价CT对脑发育性静脉异常(DVA)的诊断价值,提高对本病的认识。方法 5例脑发育性静脉异常患者中全部行CT检查。对DVA在CT检查的表现进行分析,对DVA的部位、分型、引流方式以及合并的其它异常进行探讨。结果 5例患者有5个DVA,其中1例多发。均发生在幕上,表浅型1例和皮质下型4例,引流静脉均为单支引流,未见多支引流。CTA均能清晰显示其特征性表现即"水母头"状扩张的髓静脉汇入粗大的引流静脉干。结论 CTA能正确诊断和评价DVA。

元江箭竹维管束及韧皮部纤维细胞壁发育过程

通过对5个不同龄级元江箭竹秆中维管束和导管形态结构进行观察,对韧皮纤维细胞壁厚度和层数进行分析,总结元江箭竹韧皮部纤维细胞壁的发育变化特征,建立纤维细胞壁增厚的相关模型。结果表明,元江箭竹维管束的长度和长宽比随秆龄的增长而先增大后显著减小,后生导管直径与维管束宽度随秆龄的增长而增大。细胞壁层数和厚度随秆龄的增加而增加。在成熟的元江箭竹秆中有6种纤维细胞类型,其中TypeⅡ所占比例最多。

MRI在脑发育性静脉异常中的诊断价值

目的探讨磁共振成像各种方法对脑发育性静脉异常的诊断价值。方法回顾性分析本院16例17处脑发育性静脉异常(DVA)经MRI诊断为脑静脉畸形病例,所有患者均进行过磁共振常规T1WI、T2WI、T2FLAIR、DWI和T1WI增强扫描,其中部分病例做过SWI、MRV扫描。结果DVA位于幕上区有12个,幕下区5个;引流静脉在T1WI、T2WI、T2FLAIR均表现流空低信号,髓静脉大部分为细条状或丝瓜囊状长T1、长T2信号、T2FLAIR低信号;DWI、SWI引流静脉及髓静脉区域均为斑点状或细条状低信号;TIWI增强扫描:所有病例均见髓静脉呈轮辐状或树枝状汇入引流静脉;MRV直观而形象地显示引流静脉及其引流方向,类似于脑血管造影表现,但对髓静脉的显示不及增强扫描。16例患者中6例合并海绵状血管瘤。结论 MRI常规扫描结合T1WI增强扫描及MRV可明确诊断脑DVA及其并发症,可替代脑血管造影检查。

针刺联合推拿辅助治疗小儿脑瘫的效果分析

目的分析针刺联合推拿辅助治疗小儿脑瘫的效果。方法选取该院2017年7月—2018年6月收治的脑瘫患儿240例,采用随机数字法分为两组。对照组给予综合康复训练,观察组在对照组基础上给予针刺联合推拿辅助治疗,分析两组患儿治疗后的临床效果。结果观察组总有效率(90.83%,109/120)高于对照组(76.67%,92/120),差异具有统计学意义(P<0.05)。两组治疗前发育商(DQ)值组间比较,差异不具有统计学意义(P>0.05)。观察组治疗后DQ值(79.89±9.07)分高于对照组(P<0.05)。两组治疗前白细胞介素-10(IL-10)、肿瘤坏死因子-α(TNF-α)、血管内皮生长因子(VEGF)水平组间比较,差异不具有统计学意义(P>0.05)。观察组治疗后IL-10水平高于对照组,TNF-α、VEGF水平低于对照组(P<0.05)。观察组患儿下肢肌张力整体优于对照组,差异具有统计学意义(P<0.05)。结论针刺联合推拿辅助治疗小儿脑瘫可提高患儿发育商,调节IL-10、TNF-α、VEGF的表达水平,改善下肢肌张力。

High-concentration sevoflurane exposure in mid-gestation induces apoptosis of neural stem cells in rat offspring

Sevoflurane is the most commonly used volatile anesthetic during pregnancy.The viability of neural stem cells directly affects the development of the brain.However,it is unknown whether the use of sevoflurane during the second trimester affects the survival of fetal neural stem cells.Therefore,in this study,we investigated whether exposure to sevoflurane in mid-gestation induces apoptosis of neural stem cells and behavioral abnormalities.On gestational day 14,pregnant rats were anesthetized with 2% or 3.5% sevoflurane for 2 hours.The offspring were weaned at 28 days and subjected to the Morris water maze test.The brains were harvested to examine neural stem cell apoptosis by immunofluorescence and to measure Nestin and SOX-2 levels by western blot assay at 6,24 and 48 hours after anesthesia as well as on postnatal day（P） 0,14 and 28.Vascular endothelial growth factor（VEGF） and phosphoinositide 3-kinase（PI3 K）/AKT pathway protein levels in fetal brain at 6 hours after anesthesia were assessed by western blot assay.Exposure to high-concentration（3.5%） sevoflurane during mid-gestation increased escape latency and path length to the platform,and it reduced the average duration spent in the target quadrant and platform crossing times.At 6,24 and 48 hours after anesthesia and at P0,P14 and P28,the percentage of Nestin/terminal deoxynucleotidyl transferase d UTP nick end labeling（TUNEL）-positive cells was increased,but Nestin and SOX-2 protein levels were decreased in the hippocampus of the offspring.At 6 hours after anesthesia,VEGF,PI3 K and phospho-AKT（p-AKT） levels were decreased in the fetal brain.These changes were not observed in animals given low-concentration（2%） sevoflurane exposure.Together,our findings indicate that exposure to a high concentration of sevoflurane（3.5%） in mid-gestation decreases VEGF,PI3 K and p-AKT protein levels and induces neural stem cell apoptosis,thereby causing learning and memory dysfunction in the offspring.

Stem cell lineage in body layer specialization and vascular patterning of rice root and leaf

Since the first appearance of vascular plants during evolution, the plant body has become specialized for adaption to land conditions. Much of our knowledge of plant body specialization and the origins of tissues from stem cells have been obtained from studies on the dicot Arabidopsis thaliana. However, less is known about plant body specialization in monocots, another important branch of angiosperms. In this study, we analyzed stem cell lineage and differentiation during development of the root and leaf of the monocot model plant rice(Oryza sativa). Our results showed that three body layers of rice are established from stem cells accompanied by progressively reduced pluripotency. Layer 1(L1) is a single-cell layer of epidermis; L2 is the cortex/endodermis in the root and the mesophyll in the leaf; and L3 is the site of vascular initiation. At least two common steps in vascular development are shared between rice root and leaf. The preprocambium divides to form the procambium and root pericycle or leaf outer sheath. The procambium further differentiates into the xylem, phloem and circumambient cells. We found that the outer sheath of leaf vascular bundles originates not only from the preprocambium of L3,but also from the mesophyll precursor cells of L2. In addition, WUSCHEL-RELATED HOMEOBOX(WOX)genes are expressed in not only the stem cell niche but also metaxylem precursor in rice. This pattern differs from that of homologs in Arabidopsis, suggesting that WOX functions have been recruited in different stem cells in dicots and monocots.