How do neurons age?A focused review on the aging of the microtubular cytoskeleton

Aging is the leading risk factor for Alzheimer’s disease and other neurodegenerative diseases. We now understand that a breakdown in the neuronal cytoskeleton, mainly underpinned by protein modifications leading to the destabilization of microtubules, is central to the pathogenesis of Alzheimer’s disease. This is accompanied by morphological defects across the somatodendritic compartment, axon, and synapse. However, knowledge of what occurs to the microtubule cytoskeleton and morphology of the neuron during physiological aging is comparatively poor. Several recent studies have suggested that there is an age-related increase in the phosphorylation of the key microtubule stabilizing protein tau, a modification, which is known to destabilize the cytoskeleton in Alzheimer’s disease. This indicates that the cytoskeleton and potentially other neuronal structures reliant on the cytoskeleton become functionally compromised during normal physiological aging. The current literature shows age-related reductions in synaptic spine density and shifts in synaptic spine conformation which might explain age-related synaptic functional deficits. However, knowledge of what occurs to the microtubular and actin cytoskeleton, with increasing age is extremely limited. When considering the somatodendritic compartment, a regression in dendrites and loss of dendritic length and volume is reported whilst a reduction in soma volume/size is often seen. However, research into cytoskeletal change is limited to a handful of studies demonstrating reductions in and mislocalizations of microtubule-associated proteins with just one study directly exploring the integrity of the microtubules. In the axon, an increase in axonal diameter and age-related appearance of swellings is reported but like the dendrites, just one study investigates the microtubules directly with others reporting loss or mislocalization of microtubule-associated proteins. Though these are the general trends reported, there are clear disparities between model organisms and brain regions that are worthy of further investigation. Additionally, longitudinal studies of neuronal/cytoskeletal aging should also investigate whether these age-related changes contribute not just to vulnerability to disease but also to the decline in nervous system function and behavioral output that all organisms experience. This will highlight the utility, if any, of cytoskeletal fortification for the promotion of healthy neuronal aging and potential protection against age-related neurodegenerative disease. This review seeks to summarize what is currently known about the physiological aging of the neuron and microtubular cytoskeleton in the hope of uncovering mechanisms underpinning age-related risk to disease.

PCDH17 restricts dendritic spine morphogenesis by regulating ROCK2-dependent control of the actin cytoskeleton,modulating emotional behavior

Proper regulation of synapse formation and elimination is critical for establishing mature neuronal circuits and maintaining brain function.Synaptic abnormalities,such as defects in the density and morphology of postsynaptic dendritic spines,underlie the pathology of various neuropsychiatric disorders.Protocadherin 17(PCDH17)is associated with major mood disorders,including bipolar disorder and depression.However,the molecular mechanisms by which PCDH17 regulates spine number,morphology,and behavior remain elusive.In this study,we found that PCDH17 functions at postsynaptic sites,restricting the number and size of dendritic spines in excitatory neurons.Selective overexpression of PCDH17 in the ventral hippocampal CA1 results in spine loss and anxiety-and depression-like behaviors in mice.Mechanistically,PCDH17 interacts with actin-relevant proteins and regulates actin filament(F-actin)organization.Specifically,PCDH17 binds to ROCK2,increasing its expression and subsequently enhancing the activity of downstream targets such as LIMK1 and the phosphorylation of cofilin serine-3(Ser3).Inhibition of ROCK2 activity with belumosudil(KD025)ameliorates the defective F-actin organization and spine structure induced by PCDH17 overexpression,suggesting that ROCK2 mediates the effects of PCDH17 on F-actin content and spine development.Hence,these findings reveal a novel mechanism by which PCDH17 regulates synapse development and behavior,providing pathological insights into the neurobiological basis of mood disorders.

Scinderin promotes glioma cell migration and invasion via remodeling actin cytoskeleton

BACKGROUND Glioma is one of the most common intracranial tumors,characterized by invasive growth and poor prognosis.Actin cytoskeletal rearrangement is an essential event of tumor cell migration.The actin dynamics-related protein scinderin(SCIN)has been reported to be closely related to tumor cell migration and invasion in several cancers.AIM To investigate the role and mechanism of SCIN in glioma.METHODS The expression and clinical significance of SCIN in glioma were analyzed based on public databases.SCIN expression was examined using real-time quantitative polymerase chain reaction and Western blotting.Gene silencing was performed using short hairpin RNA transfection.Cell viability,migration,and invasion were assessed using cell counting kit 8 assay,wound healing,and Matrigel invasion assays,respectively.F-actin cytoskeleton organization was assessed using F-actin staining.RESULTS SCIN expression was significantly elevated in glioma,and high levels of SCIN were associated with advanced tumor grade and wild-type isocitrate dehydrogenase.Furthermore,SCIN-deficient cells exhibited decreased proliferation,migration,and invasion in U87 and U251 cells.Moreover,knockdown of SCIN inhibited the RhoA/focal adhesion kinase(FAK)signaling to promote F-actin depolymerization in U87 and U251 cells.CONCLUSION SCIN modulates the actin cytoskeleton via activating RhoA/FAK signaling,thereby promoting the migration and invasion of glioma cells.This study identified the cancer-promoting effect of SCIN and provided a potential therapeutic target for the treatment of glioma.

Regulation of actin cytoskeleton via photolithographic micropatterning

Actin cytoskeleton plays crucial roles in various cellular functions.Extracellular matrix(ECM)can modulate cell morphology by remodeling the internal cytoskeleton.To define how geometry of ECM regulates the organization of actin cytoskeleton,we plated individual NIH 3T3 cells on micropatterned substrates with distinct shapes and sizes.It was found that the stress fibers could form along the nonadhesive edges of T-shaped pattern,but were absent from the opening edge of V-shaped pattern,indicating that the organization of actin cytoskeleton was dependent on the mechanical environment.Furthermore,a secondary actin ring was observed on 50μm circular pattern while did not appear on 30μm and 40μm pattern,showing a size-dependent organization of actin cytoskeleton.Finally,osteoblasts,MDCK and A549 cells exhibited distinct organization of actin cytoskeleton on T-shaped pattern,suggesting a cell-type specificity in arrangement of actin cytoskeleton.Together,our findings brought novel insight into the organization of actin cytoskeleton on micropatterned environments.

Targeting cancer cytoskeleton: the mechanical properties of natural anticancerdrugs

Anticancer drugs are one of the most direct means of cancer therapy.However,the various cancer progressions hamper the development and discovery of anticancer drugs.In fact,the mechanical properties of the tumor cytoskeleton are extremely vital for any phase of cancer,especially in tumor invasion and metastasis.However,in the current category of anticancer drugs,the cytoskeleton-targeting drugs are limited and their role in tumor progression is unclear.Here,we present the mechanical characteristics of tumor stiffness that are tightly regulated by the cancer cytoskeleton,including actin filaments and microtubules during tumor initiation,growth and metastasis,and review the natural drugs that target the cancer cytoskeleton.We define cytoskeleton dynamics as target mechanisms for anticancer drugs and summarize the plant,microbial and marine sources of natural products.Furthermore,this paper also provides a material pathway to study active tumor mechanics,and introduces the unique advantages and future application potential of tumor cytoskeleton-targeting drugs in clinical use.The material approaches to active cancer mechanics are supplied in this review.We aim to promote the development of anticancer drugs that target tumor mechanics by using those material approaches and finding their pharmacological application.

细丝蛋白A在肿瘤中作用机制的研究进展

细丝蛋白A(filamin A,FLNA)是一种肌动蛋白结合蛋白,参与人的多种生理和病理作用。随着分子生物学的发展和人们对肿瘤认识的深入,越来越多的证据表明FLNA及其广泛的伙伴蛋白在乳腺癌、结直肠癌、前列腺癌、非小细胞肺癌等常见肿瘤中构成了精密的分子调控网络,并在肿瘤发生发展、侵袭、转移和耐药等方面发挥着重要作用。FLNA及其伙伴蛋白很可能成为新的肿瘤分子标志物和治疗靶点,为肿瘤的诊断和治疗提供新的方向。本文主要综述了FLNA结构功能特点以及在其肿瘤中作用的研究进展。

ATP5J通过TOMM20调节线粒体功能并促进人肝细胞癌细胞转移

目的:探讨ATP合成酶H+转运线粒体F0复合体亚基F6(ATP5J)通过调节肝癌细胞线粒体功能介导细胞骨架重塑影响肝癌细胞转移的作用及其机制。方法:培养人肝细胞癌Li-7细胞株,基因修饰ATP5J表达(过表达和敲减)。使用JC-1染色检测每组细胞线粒体膜电位情况;利用DCFH-DA荧光探针检测Li-7细胞的活性氧(ROS)含量;线粒体ATP荧光探针检测线粒体功能;微丝绿色荧光探针(Actin-Tracker Green-488)检测细胞骨架重塑情况;Transwell检测细胞侵袭能力;Western blot检测ATP5J和线粒体外膜转位酶20(TOMM20)的表达水平。结果:过表达ATP5J可上调线粒体膜电位水平和线粒体ATP荧光强度、诱导细胞骨架重塑、促进细胞侵袭和TOMM20蛋白表达,抑制ROS生成(P<0.01)。相反,敲减ATP5J显著降低线粒体膜电位和线粒体ATP荧光强度,显著降低细胞侵袭能力和TOMM20表达,促进ROS产生,阻断细胞骨架重塑(P<0.01)。结论:ATP5J可调节肝癌细胞线粒体能量转化,其通过TOMM20调节线粒体膜电位水平和线粒体ATP产生介导细胞骨架重塑影响肝癌细胞转移。

褪黑素缓解白消安损伤小鼠睾丸的机理研究

旨在揭示褪黑素(melatonin, MT)缓解白消安损伤睾丸的机理,提高白消安制备精原干细胞移植受体的效率,并探究其对白消安毒害雄性生精机能的治疗作用。本研究以6~7周ICR雄鼠为模型动物,分为对照组,白消安处理组和白消安+褪黑素处理组,每组8个重复,于注射后第7天取样。通过ELISA检测睾丸组织的炎性细胞因子水平,并对睾丸和附睾进行HE染色。此外,免疫组化或免疫荧光检测血睾屏障(blood-testis barrier, BTB)相关蛋白的表达情况,以分析MT对BTB影响。结果表明,小鼠经白消安注射后,联合MT处理,观察到MT显著缓解了睾丸重和睾体率下降的趋势,并减缓了精子数量下降的速度;睾丸组织HE染色和炎性细胞因子检测发现,MT显著减缓了核转录因子κB(nuclear transportation factorκB,NF-κB)、p-NF-κB、白介素-1β(interleukin-1β,IL-1β)、肿瘤坏死因子-ɑ(tumor necrosis factor-ɑ,TNF-α)及髓过氧化物酶(myeloperoxidase, MPO)水平的上升趋势,从而减少了组织中炎性细胞浸润;免疫组化或免疫荧光检测发现,MT缓解了白消安处理导致的BTB组成蛋白(Occludin、connexin-43、N-cadherin)和细胞骨架蛋白(F-actin和Vimentin)含量的下降。综上,MT通过下调睾丸组织中炎性细胞因子水平,缓解白消安诱发的小鼠睾丸炎症反应;并通过减缓BTB相关蛋白含量的下降,缓解白消安对BTB和支持细胞的损伤,进而缓解小鼠生精机能的损伤。

Piezo1通过驱动肌动蛋白细胞骨架重塑促进宫颈癌侵袭迁移的机制研究

目的 探讨Piezo1通过驱动肌动蛋白细胞骨架重塑在宫颈癌侵袭迁移中的作用及机制。方法 采用免疫组化和Western blot法检测宫颈癌组织和细胞系中Piezo1和F-actin的表达;慢病毒转染沉默宫颈癌细胞系Siha及Hela中Piezo1基因,利用Transwell实验研究Piezo1对宫颈癌侵袭和迁移的影响,鬼笔环肽染色观察Piezo1对肌动蛋白细胞骨架的重塑作用,并进一步通过干预细胞骨架聚合状态以证实Piezo1影响宫颈癌侵袭迁移的机制。结果 宫颈癌组中Piezo1和F-actin表达量显著高于对照组,且有转移的宫颈癌组比无转移的宫颈癌组表达更高;沉默Piezo1下调了SiHa及HeLa细胞系中F-actin的表达,并抑制宫颈癌侵袭和迁移,这种抑制作用可被肌动蛋白聚合诱导剂Jasplakinolide部分解除,而激动Piezo1则上调F-actin表达,且促进宫颈癌侵袭和迁移,这种促进作用可被肌动蛋白解聚剂Latrunculin A所抑制。结论 Piezo1在宫颈癌中高表达,并驱动肌动蛋白细胞骨架重塑以促进宫颈癌侵袭和迁移。

PAK4在细胞骨架和细胞周期调控中的作用研究进展

p21活化蛋白激酶(p21-activated protein kinase,PAK)是一类高度保守的丝氨酸/苏氨酸蛋白家族,是Rho家族小GTP酶的效应蛋白,参与多种信号通路传导。PAK4是PAK家族中最有代表性的成员,通过磷酸化下游底物,调控细胞骨架重组、细胞增殖和细胞周期进展等。PAK4过表达见于胰腺癌、胃癌和卵巢癌等多种肿瘤,参与肿瘤发生和肿瘤迁移等过程。研究PAK4的结构、作用机制对于揭示细胞周期调控和肿瘤生物学行为有重要价值。本文阐述和归纳了PAK4的结构、激活过程及其在细胞骨架、细胞周期进展中的生物学作用,并综述了PAK4调控妇科肿瘤发生发展以及PAK4抑制剂的最新研究进展。

肌球蛋白轻链激酶在恶性肿瘤中的研究进展

近年来,肌球蛋白轻链激酶(MLCK)作为细胞骨架和细胞运动的重要调节因子,在多种肿瘤的发生发展中发挥着关键作用。MLCK通过细胞信号转导,参与调控肿瘤细胞的增殖、迁移、侵袭和凋亡等生物过程。鉴于MLCK在肿瘤发展中的关键作用,其作为肿瘤治疗的潜在靶点被广泛研究,旨在开发针对MLCK的治疗策略,以提高治疗效率和患者生存质量。本文综述了MLCK在不同类型肿瘤中的表达模式、功能机制及其潜在的临床应用价值,同时探讨了MLCK作为潜在治疗靶点的研究现状及未来发展方向,为临床治疗提供新的思路和策略。

环境污染物诱导细胞膜损伤的研究进展

细胞膜是保护细胞免受外源性污染物破坏的屏障,在细胞与外界进行物质运输、能量转换、信息传递等活动中具有不可替代的作用。当前针对环境污染物诱导细胞膜损伤的研究相对零散,未成体系。本文聚焦近5年国内外环境污染物诱导细胞膜损伤的相关研究并对其进行归纳总结,主要从脂质双分子层、膜蛋白、细胞骨架以及膜微结构域4个方面分析了环境污染物对细胞膜的损伤影响。从脂质双分子层结构变化、脂质过氧化以及膜通透性和完整性等方面描述了环境污染物对脂质双分子层的损伤;从膜蛋白活性、蛋白表达等方面阐述了环境污染物对细胞膜蛋白的损伤;从微管、微丝和中间纤维的变化归纳了环境污染物对细胞骨架的损伤;从脂筏和小窝的变化概括了环境污染物对细胞膜微结构域的损伤。最后,对环境污染物诱导细胞膜损伤的研究现状进行了思考,并对未来研究趋势进行了展望。

Anagliptin通过SOD-1/ROS调控细胞骨架蛋白生成抑制CT-26细胞迁移的实验研究

目的研究二肽基肽酶-4(DPP-4)抑制剂Anagliptin对结直肠癌细胞迁移的作用。方法体外培养CT-26细胞;CCK-8实验检测细胞活力;蛋白质印迹实验(Western blotting)检测超氧化物歧化酶-1(SOD-1)和超氧化物歧化酶-2(SOD-2)表达;Transwell小室检测细胞迁移能力;免疫荧光实验检测细胞骨架蛋白(F-actin)和细胞内活性氧原(ROS)形成。结果CCK-8实验显示,2 mmol/L Anagliptin具有促CT-26细胞凋亡作用(P<0.01)。1 mmol/L Anagliptin孵育CT-26细胞后,CT-26细胞迁移能力明显下降(0.375±0.028,P<0.01)。共孵育Anagliptin和Tempol(ROS清除剂)后可明显拮抗由Anagliptin所引起的CT-26细胞迁移抑制(0.527±0.035,P<0.01)及细胞内ROS累积(1.395±0.0553,P<0.01)。CT-26细胞孵育Anagliptin后,细胞内SOD-1表达下降(0.665±0.028,P<0.01),而SOD-2表达无变化(P>0.05)。SOD抑制剂DDC孵育CT-26细胞后,细胞迁移能力明显下降(0.206±0.009,P<0.01)。共孵育Anagliptin和Tempol后拮抗由Anagliptin所引起的CT-26细胞骨架蛋白F-actin合成下降。结论Anagliptin通过SOD-1/ROS途径调控细胞骨架蛋白(F-actin)生成抑制CT-26细胞迁移。

空间微重力下细胞力学感知-传导的研究进展

在重力场下,绝大多数细胞功能受到力学载荷的调控。空间微重力下细胞对力学载荷的响应能力在空间机体生理功能适应性变化中的作用不容忽视。细胞骨架被普遍认为是细胞感知重力变化及响应力学载荷的关键结构之一。本文总结了微重力下“细胞骨架-LINC复合物-核纤层”这一细胞力学感知-传导途径变化及作用机制的研究进展,并对未来的研究工作进行展望。

The Change of Microtubule Cytoskeleton in the Stem-Tip Cells of Sugarcane during Mitosis

In order to understand the microtubule change of monocotyls stem-tip during mitosis, the arrangement, transformation of microtubule array and its relation with chromosome movement during mitosis were studied with freezing microtome, indirect immunofluoreseenee, DAPI staining and fluorescence microscopy. The results showed that nucleolus was intact when the cortical microtubules formed; cortical microtubules were changed into phramoplast microtubules bands at mitosis prophase. When phramoplast microtubules came into being, nuclear membrane was ruptured and chromosome was arranged at the position of cell plate ; subsequently, phramoplast microtubules were changed into phragmoplast microtubules, phramoplast microtubules were shortening and microtubules on the sides of cell plate were increasing gradually, during this course sister ehromatid was separated by microtubules at cell plate and tract to the two poles, forming phragmoplast microtubules. Then the nucleolus of two daughter cells formed and separated in the end with the increase of cells numbers. Therefore, cell division orientation could be judged from the arrangement of cell microtubules in different periods in order to understand its growth status.

基于细胞力传感器探索卵泡发育机制

细胞力传感器在卵泡正常发育过程中发挥着重要作用,它由整合素、黏着斑、信号通路和细胞骨架组成。在卵泡发育过程中,细胞力传感器能将力学刺激转化为生化信号,激活信号通路,使细胞骨架响应刺激,促进生殖细胞迁移、减数分裂和排卵。从力传感器在卵泡发育中的作用和相关信号通路等两方面探讨卵泡发育作用机制,为卵泡发育的深入研究提供新思路。

Talin1对人输卵管上皮细胞黏附功能的调控作用

目的:探讨踝蛋白1(Talin1)对人输卵管上皮细胞黏附功能的影响及潜在的分子机制。方法:人正常输卵管上皮细胞内转染Talin1过表达质粒以构建过表达Talin1稳定细胞株,以人正常输卵管上皮细胞为对照,采用细胞黏附实验检测过表达Talin1人输卵管上皮细胞黏附力变化,免疫荧光法观察过表达Talin1人输卵管上皮细胞中细胞骨架变化及纤毛动力蛋白的表达;实时荧光定量聚合酶链反应(quantitative real-time polymerase chain reaction,qRT-PCR)及蛋白质印迹法(Western blotting)分别检测过表达Talin1人输卵管上皮细胞中黏附因子以及细胞微丝骨架蛋白的mRNA及蛋白表达。结果:人正常输卵管上皮细胞内转染Talin1过表达质粒后,Talin1的mRNA和蛋白表达量均升高(P<0.05),成功构建了过表达Talin1稳定细胞株;Talin1使输卵管上皮细胞的黏附力显著增强(P<0.01),细胞骨架F-肌动蛋白(F-actin)、纤毛动力蛋白中轴丝动力蛋白重链5(dynein axonemal heavy chain 5,DNAH5)、叉头框转录因子J1(forkhead box J1,FOXJ1)和放射状的辐条结构头蛋白9(radial spoke head component 9,RSPH9)的平均荧光强度明显增强(均P<0.01);Talin1可下调黏附因子E-钙黏蛋白(E-cadherin)的mRNA及蛋白表达(均P<0.001),上调黏附因子β-连环蛋白(β-catenin)、P120连环蛋白(P120ctn)、细胞间黏附分子-1(intercelluar adhesion molecule-1,ICAM-1)的mRNA及蛋白表达(均P<0.05)和桩蛋白(Paxillin)、β-微管蛋白(β-tubulin)、角蛋白(Keratin,Krt)的蛋白表达(均P<0.0001)。结论:输卵管妊娠的发生可能与Talin1促进细胞骨架蛋白的表达及重排,调控相关黏附分子的表达干预输卵管上皮细胞的黏附性有关。

二氢嘧啶酶样蛋白3在肿瘤中的表达

二氢嘧啶酶样蛋白3(dihydropyrimidinase-like 3,DPYSL3)又称塌陷反应调节蛋白4(collapse response mediator protein 4,CRMP4),是一种在神经系统中高表达的胞质磷蛋白。其不仅参与细胞伪足中肌动蛋白的组成,也用于组装细胞骨架,还与细胞上皮-间质转化(epithelial-mesenchymal transition,EMT)过程有关,这些特性可能与肿瘤增殖与转移功能有关。近年来有研究表明,DPYSL3参与多种癌细胞的增殖与侵袭过程,例如前列腺癌、膀胱癌、胃癌与肝癌等。然而,DPYSL3在不同肿瘤中的表达与预后存在明显的异质性。因此,进行DPYSL3在肿瘤表达水平的研究有望成为在不同肿瘤恶性程度与诊断过程中的生物标志物,从而提高肿瘤诊断率与患者预后水平。本文对DPYSL3在不同肿瘤中的表达、生物学功能及其对肿瘤的诊断、治疗及预后价值进行总结与探索,为肿瘤研究提供新思路。

低氧环境中Rac1调节破骨细胞功能的实验研究

目的:探究低氧条件下低氧诱导因子-1α(hypoxia-inducible factor-1α,HIF-1α)通过调控Rac1对细胞骨架的影响及其调节破骨细胞骨吸收功能变化的作用。方法:利用氯化钴(cobalt dichloride,CoCl2)刺激小鼠单核细胞系RAW264.7建立体外低氧破骨细胞培养体系。采用sRANKL条件培养液诱导RAW264.7细胞分化,利用CoCl2模拟低氧环境刺激细胞,7 d后行TRAP染色;利用实时定量聚合酶链反应(real-time quantitative polymerase chain reaction,RTqPCR)、细胞免疫荧光检测和蛋白质印迹法(Western blotting)检测低氧下破骨细胞表达HIF-1α、Rac1及破骨细胞相关表面标志物与封闭带的情况;同时检测HIF-1α条件性敲除细胞株RAW264.7及Rac1活性抑制剂对相同条件下破骨细胞相关基因和封闭带的影响。结果:低氧环境可促使RAW264.7诱导形成的破骨细胞体积增大、骨吸收能力增强(P<0.01)。低氧组破骨细胞表达的Rac1 mRNA水平升高,且封闭带表达显著(P<0.001)。HIF-1αKO RAW264.7细胞诱导形成破骨细胞体积减小,HIF-1α表达显著降低,Rac1也随之降低(P<0.001);同时,抑制剂组诱导生成的破骨细胞体积减小,HIF-1α表达保持不变,封闭带形成异常(P<0.01)。结论:小鼠单核细胞系RAW264.7在低氧环境下可通过HIF-1α调控Rac1来影响其所形成的破骨细胞细胞骨架,进而改变破骨细胞的骨吸收能力。

溶质载体家族成员7A11与肿瘤免疫调节和耐药关系的研究进展

溶质载体家族成员7A11(SLC7A11)是位于细胞质膜上的胱氨酸转运体,其主要功能是调节谷胱甘肽(GSH)合成、氧化还原维持以及肿瘤的生长和转移等,在多种类型的实体瘤中显著高表达,并参与细胞的铁死亡和双硫死亡过程。SLC7A11对肿瘤的发生发展、免疫调节以及对药物反应的调控等方面均具有重要影响,并为当前大部分肿瘤临床治疗方案的改进提供了依据。