自噬在中枢神经系统发育、老化和损伤中作用的研究进展

正自噬是一种广泛存在于真核细胞,进化上高度保守的溶酶体介导的自我降解过程,主要通过消耗糖原、蛋白质等大分子物质和受损细胞器并循环利用所产生能量,以维持细胞内环境的稳定[1]。根据细胞物质运送到溶酶体内的途径不同,自噬可分为巨自噬(Macro autophagy)、微自噬(Micro autophagy)和分子伴侣介导的自噬(Chaperone-mediated autophagy,CMA)。巨自噬是目前研究自噬的主要类型,其主要特征是形     

肾癌中细胞自噬的作用及自噬调节剂在肾癌治疗中的研究进展

细胞自噬是细胞体内的一种“自我吞噬”的分解代谢过程,通过将细胞内衰老的细胞器、受损蛋白和其他细胞成分包裹于自噬溶酶体中,从而实现能量供应和物质的循环利用。研究表明,细胞自噬与肾癌的发生、发展和转归密切相关,其不仅参与肾癌的发生,而且在肾癌发展的不同阶段分别起促进或抑制的双重作用。有针对性地靶向调节不同阶段肾癌的自噬水平可能是治疗肾癌的新策略。该文对细胞自噬的发生过程及其在肾癌发展进程中的作用进行综述,并探讨自噬调节剂(自噬抑制剂/诱导剂)在肾癌治疗中的潜在作用。     

细胞自噬机制开启疾病治疗新途径

自噬是指细胞内细胞器和蛋白质等在溶酶体被降解及其降解产物被重新利用的过程。日本科学家大隅良典(Yoshinori Ohsumi)发现了15个自噬相关基因并阐述了自噬机制,获得2016年诺贝尔生理学与医学奖。他的开创性研究成果为探讨细胞自噬的生理和病理作用奠定了重要基础,并为通过调节细胞自噬治疗疾病开辟了新途径。自噬是一种普遍性细胞反应,正常情况下细胞自噬水平很低,受生理或病理性刺激后自噬水平显著升高。自噬相关基因缺失或自噬功能障碍时可导致某些疾病的发生。近来,人们试图通过激活或抑制细胞自噬预防和治疗自噬障碍相关性疾病。     

细胞自噬:病理学研究的新热点

自噬(autophagy)是真核细胞中一种普遍而又重要的生命现象,其主要作用是清除和降解自身受损的细胞器以及多余的生物大分子,并利用降解产物提供能量和重建细胞结构,在维持细胞稳态和细胞生命活动等方面起重要作用.本文就近年来在自噬过程、自噬信号转导途径以及自噬的分子机制和调控机制、自噬与细胞生存、凋亡和肿瘤等方面取得的一些进展进行综述.     

自噬在破骨细胞分化过程中的调控作用

破骨细胞在骨吸收过程中发挥着重要作用,其形成和功能失调可参与骨质疏松、类风湿性关节炎等多种骨相关疾病的发生。破骨细胞的形成和分化是一个复杂的生物学过程,其调控机制尚未完全明了。本研究旨在探讨自噬在破骨细胞分化过程中的作用。在RANKL刺激下,小鼠巨噬细胞RAW264.7可被诱导分化为破骨细胞。本研究采用TRAP染色法检测RAW264.7细胞向破骨细胞分化进程中抗酒石酸酸性磷酸酶活性变化,并通过Western blotting技术检测分析自噬相关蛋白LC3表达变化;并应用自噬抑制剂3-甲基腺嘌呤(3-Methyladenine,3-MA)明确自噬在破骨细胞分化中的作用。30ng/ml的RANKL刺激RAW264.7细胞至第5d时可观察到分化成熟的破骨细胞。在此过程中,RANKL刺激至第3d时细胞自噬作用显著增强,此后(如第5d时)自噬作用则逐渐减弱。在分化过程中如果以3-MA抑制细胞的自噬,RAW264.7细胞向破骨细胞的分化则可被显著抑制。可见,自噬在RANKL介导的破骨细胞分化成熟的过程中发挥重要的调控作用,抑制自噬则阻碍破骨细胞的分化成熟。     

细胞自噬与凋亡相互作用分子机制的研究进展

细胞自噬与细胞凋亡是两个不同的生理现象,但其在功能上有着密切的联系。本文主要介绍细胞自噬和凋亡的分类及发生过程,并就自噬体形成过程中的一些关键调节蛋白以及凋亡和抗凋亡蛋白的双重作用对自噬和凋亡的影响进行论述,从而探讨细胞自噬与凋亡之间的关系,以期为进一步研究自噬与凋亡相关疾病提供理论基础。     

自噬调控在淋巴瘤中的研究进展

自噬是一种多步骤溶酶体降解途径,一方面对稳态维持至关重要,另一方面又与多种疾病的发生、发展有关。这个过程受到复杂的网络调控,主要包括mTOR依赖的信号通路,和其他如与Ca~(2+)、活性氧、RNA、表观遗传、翻译机制等相关的调控途径。细胞自噬与淋巴瘤的发生发展密切相关,目前研究发现在淋巴瘤中存在多种途径参与自噬的调控,该文主要阐述细胞自噬调控途径及在淋巴瘤中的研究进展。     

自噬与卵巢癌的研究进展

细胞自噬(autophagy)是将细胞内受损、变性或衰老的蛋白质以及细胞器运输到溶酶体进行消化降解的过程。近期研究发现自噬不仅对细胞内自我平衡调节起着重要作用,而且在肿瘤的发生发展中起着双刃剑的作用。研究自噬的分子机制以及自噬与卵巢癌的关系对卵巢癌防治有重大意义。     

细胞自噬在血管新生中作用的研究进展

自噬(autophagy)是细胞利用溶酶体降解自身受损的细胞器和大分子物质的过程,在稳定细胞内环境中发挥着重要作用。在血管新生的病理生理过程中,细胞自噬作用持续存在。从自噬的角度探索血管新生的发生发展进程,能够为临床治疗血管相关疾病提供新的思路。     

登革病毒与细胞自噬

登革病毒(dengue virus,DENV)在胞内复制、宿主间传播和机体内致病机制等方面均受到细胞自噬的影响,本文依据国内外最新研究进展以DENV与细胞自噬的关系为重点展开综述。自噬是一种真核生物普遍具备的、用于应对外界压力和维持细胞内稳态的程序性蛋白降解途径,其在保护细胞免受病毒等外源病原体侵染的机制中发挥重要作用。但是自噬在DENV的复制过程中发挥了相反的作用。自噬不仅为病毒复制提供了复制场所,而且为其提供能量来源,细胞自噬还参与了部分DENV致病过程。总之,自噬有助于DENV的复制。     

细胞自噬的形态学特征和功能意义

目的 自噬是细胞受到刺激后吞噬自身的细胞质或细胞器,最终将吞噬物在溶酶体内降解的过程.按吞噬物进入溶酶体的途径,自噬可分为巨自噬、微自噬和分子伴侣介导的自噬3类.在巨自噬,自噬前体包裹细胞质或细胞器后形成自噬体,继而自噬体与溶酶体结合形成自噬溶酶体,自噬体内容物被降解.在微自噬,溶酶体膜凹陷,直接吞噬细胞质、细胞器或细胞核,形成自噬体,然后被溶酶体酶降解.分子伴侣介导的自噬是通过溶酶体膜的受体将细胞质内的蛋白质转运入溶酶体.自噬从酵母至哺乳动物细胞均很保守,对于耐受饥饿和缺血,清除衰老细胞器,清除细菌和异物,维持细胞活性和延长寿命等起着重要作用.自噬活动受自噬基因的调控,自噬基因缺失或功能障碍时可导致某些疾病的发生.深入认识自噬过程以及由此产生的自噬体等结构及其功能有助于探讨自噬对于人体生理和病理作用的机制.本文综述了自噬的形态学特征及其功能意义.     

Autophagy in MHC class II antigen processing

Durable adaptive immunity is dependent upon CD4 T-cell recognition of MHC class II molecules that display peptides from exogenous and endogenous antigens. Endogenously expressed cytosolic and nuclear antigens access MHC class II by way of several intracellular autophagic routes. These pathways include macroautophagy, microautophagy and chaperone-mediated autophagy. Macroautophagy can deliver antigens into autophagosomes for processing by acidic proteases before MHC class II presentation. However, other endogenous antigens are processed by cytoplasmic proteases, yielding fragments that translocate via chaperone-mediated autophagy into the endosomal network to intersect MHC class II. Cross-talk between autophagy pathways, particularly in response to stress, appears to balance the relative efficiency of each pathway. This might limit redundancy, giving MHC class II broader access to antigens within intracellular compartments distinct from the endosomal network.     

Chaperone mediated autophagy in aging: Starve to prosper

The major lysosomal proteolytic pathways essential for maintaining proper cellular homeostasis are macroautophagy, chaperone-mediated autophagy (CMA) and microautophagy. What differentiates CMA from the other types of autophagy is the fact that it does not involve vesicle formation; the unique feature of this pathway is the selective targeting of substrate proteins containing a CMA-targeting motif and the direct translocation into the lysosomal lumen, through the aid of chaperones/co-chaperones localized both at the cytosol and the lysosomes. CMA operates at basal conditions in most mammalian cell models analyzed so far, but it is mostly activated in response to stressors, such as trophic deprivation or oxidative stress. The activity of CMA has been shown to decline with age and such decline, correlating with accumulation of damaged/oxidized/aggregated proteins, may contribute to tissue dysfunction and, possibly, neurodegeneration. Herein, we review the recent knowledge regarding the molecular components, regulation and physiology of the CMA pathway, the contribution of impaired CMA activity to poor cellular homeostasis and inefficient response to stress during aging, and discuss the therapeutic opportunities offered by the restoration of CMA-dependent proteolysis in age-associated degenerative diseases.     

Fluorescent‐based evaluation of chaperone‐mediated autophagy and microautophagy activities in cultured cells

The autophagy‐lysosome protein degradation is further classified into macroautophagy (MA), microautophagy (mA), and chaperone‐mediated autophagy (CMA). While MA is involved in various functions and disease pathogenesis, little is known about CMA and mA because of the absence of easy methods to assess their activities. We have recently established a method to assess CMA activity using glyceraldehyde 3‐phosphate dehydrogenase (GAPDH), a CMA substrate, and HaloTag (HT) system. Another group has recently identified a mammalian mA pathway, in which substrates are delivered to late endosomes in an heat shock cognate protein (Hsc)70‐dependent manner. Because Hsc70 is also involved in CMA, our method would detect both CMA and mA activities. In this study, we attempted to assess CMA and mA activities separately through the siRNA‐mediated knockdown of CMA‐ and mA‐related proteins. Knockdown of LAMP2A, a CMA‐related protein, and TSG101, an mA‐related protein, significantly but only partially decreased the punctate accumulation of GAPDH‐HT in AD293 cells and primary cultured rat cortical neurons. Compounds that activate CMA significantly increased GAPDH‐HT puncta in TSG101‐knockdown cells, but not in LAMP2A‐knockdown cells, suggesting that punctate accumulation of GAPDH‐HT under LAMP2A‐ and TSG101‐knockdown represents mA and CMA activities, respectively. We succeeded in establishing the method to separately evaluate CMA and mA activities by fluorescence observation.     

Uptake--microautophagy--and degradation of exogenous proteins by isolated rat liver lysosomes. Effects of pH, ATP, and inhibitors of proteolysis

Isolated rat liver lysosomes were incubated with [14C]methemoglobin under various conditions. Optimal pH for the in vitro proteolysis was found to be 4-5. To evaluate whether or not degradation of added proteins could be due to enzyme leakage the integrity of the lysosomes was measured. Isolated lysosomes were found to be stable for up to 10 min of incubation at pH 5.5 and for 30 min at pH 7. The degradation of three different proteins (methemoglobin, ovalbumin, and lysozyme) was analyzed. No correlation was detected between rate of breakdown and physical properties of the proteins. Leupeptin, chloroquine, and propylamine inhibited proteolysis of added proteins by 45-65% in both neutral and acid milieu. Possible energy requirement was tested by the addition of Mg2+ and ATP to the incubation medium. A dose-dependent increase in proteolytic rate was found when ATP was added to the lysosomal suspension, a finding most likely due to acidification of the lysosomes and ensuing increased degradation. GTP and ITP were somewhat less effective. The noncleavable ATP analogue 5'-adenylylimidodiphosphate gave no stimulation. The ATP-driven proteolysis was inhibited by ethylmaleimide. Isolated lysosomes were also incubated with ferritin in order to visualize a possible uptake process of a protein in the electron microscope. Following incubation, ferritin particles were seen inside intralysosomal vesicles which appeared to be formed by invagination of the lysosomal membrane, a process designated microautophagy. The results thus support the notion that isolated lysosomes may micropinocytose and degrade exogenously added proteins and that this process is ATP dependent.     

Afferent connections of the nucleus centralis amygdalae

Summary The central nucleus of the amygdala has been shown to be involved in cardiovascular regulation and the integration of arousal. In this study, the afferent input was investigated in cat by microinjecting horseradish peroxidase (HRP) into the central nucleus and examining retrogradely-labelled cells in the brain. Retrograde labelling was found in the cortex next to the sulcus ectosylvius anterior, fissura lateralis Sylvii, sulcus rhinicus anterior and posterior, sulcus suprasylvius, and pyriform and entorhinal cortices as well as in the insula and claustrum. Each of the sub-nuclei of the amygdaloid complex exhibited retrogradely-labelled perikarya. Labelled cells were also found in the diagonal band of Broca, nucl. lateralis septi, and nucl. proprius striae terminalis (bed nucl. of stria terminalis). In the hypothalamus the area preoptica medialis and lateralis, nucl. dorsomedialis, paraventricularis, periventricularis, arcuatus and mammilaris medialis were labelled. The nucl. subthalamicus, zona incerta, peripeduncular system, substantia nigra, and nucl. interpeduncularis contained HRP-marked cells. In the thalamus labelled cells were observed in the nucl. reuniens, nucl. centroposterior lateralis, nucl. latero-posterior, nucl. posterior, nucl. centro-anterior, antero-dorsalis, antero-medialis, antero-lateralis, centrum mdianum, nucl. reticularis, nucl. rhomboideus, nucl. parafascicularis and subfascicularis. The area tegmentalis Tsai and the corpora geniculata also contained labelled cells. In the brain stem, HRP-marked cells could be detected in the brachium colliculi inferioris, aqueductal grey matter, locus coeruleus, nucl. parabrachialis, in various nuclei of the formatio reticularis, in the nucl. retrofascialis, nucl. solitarius, nucl. commissuralis, nucl. ambiguus and nucl. dorsalis n. vagi. The results were compared to other neuroanatomical studies and to functional studies of the amygdala.     

Efficacy of adulticidal and larvicidal properties of botanical extracts against Haemaphysalis bispinosa, Hippobosca maculata, and Anopheles subpictus

The aim of the present study was to investigate the adulticidal and larvicidal activity of dried leaf hexane, ethyl acetate, acetone, and methanol extracts of Nelumbo nucifera, Manilkara zapota, Ipomoea staphylina, and Acalypha indica against the adults of Haemaphysalis bispinosa (Acarina: Ixodidae), hematophagous fly Hippobosca maculata (Diptera: Hippoboscidae), and fourth instar larvae of malaria vector Anopheles subpictus (Diptera: Culicidae). Parasites were exposed to varying concentrations of plant extracts for 24 h. All extracts showed moderate parasitic effects; however, the percent parasitic mortality observed in the crude leaf hexane, ethyl acetate, acetone, and methanol extracts of N. nucifera and M. zapota against H. bispinosa were 80, 74, 72, and 100 and 100, 83, 74, and 91, respectively, and the activity for I. staphylina and A. indica against Hip. maculata were 100, 93, 87, and 66 and 78, 90, 87, and 100 at 2,000 ppm, respectively; the larvicidal activity for the same extracts of I. staphylina against A. subpictus were 76, 82, 84, and 100 at 100 ppm, respectively. The maximum efficacy was observed in the leaf methanol extract of N. nucifera, hexane extract of M. zapota and leaf hexane extract of I. staphylina, and methanol extract of A. indica against the adults of H. bispinosa and Hip. maculata with LC(50) and LC(90) values of 437.14 and 200.81, and 415.14 and 280.72 ppm, 1,927.57 and 703.52 ppm, and 1,647.70 and 829.39 ppm, respectively. The effective larvicidal activity was observed in leaf methanol extract of I. staphylina against A. subpictus with LC(50) and LC(90) values of 10.39 and 37.71 ppm, respectively. Therefore, this study provides the first report on the adulticidal and larvicidal activity of crude solvent extracts. This is an ideal eco-friendly approach for the control of H. bispinosa, Hip. maculata, and the medically important vector A. subpictus.     

ABO, Rh, MNS, Duffy, Kidd,Yt, Scianna, and Colton blood group systems in indigenous Chinese

The frequencies of selected alleles in the ABO, Rh, MNS, Duffy, Kidd, Yt, Scianna, and Colton blood group systems were determined among four indigenous Chinese ethnic populations: Han, Tajik, She, and Yugu. Genotypes were determined by PCR or PCR with sequence specific primers (PCR-SSP). In the Han population, the frequencies of A1, A2, B, and O1 alleles were 0.189, 0.003, 0.170, and 0.638, respectively, and the O2 allele was not identified. Among D+ Hans, the frequencies of C and c alleles were 0.67 and 0.33 and the frequencies of E and e were 0.22 and 0.78, respectively. Among D- Hans, the frequencies of C and c alleles were 0.23 and 0.77 and the frequencies of E and e were 0.04 and 0.96, respectively. The frequencies of M and N alleles were 0.478 and 0.522 among Hans and 0.655 and 0.345 among Tajiks, respectively. The frequencies of Fya and Fyb alleles were 0.94 and 0.06 among Hans and 0.98 and 0.02 among Shes, respectively. The frequencies of Jka and Jkb alleles were 0.49 and 0.51 among Hans and 0.56 and 0.44 among Shes, respectively. The frequency of the Yta allele was 1.00 among Hans. The frequencies of Yta and Ytb alleles were 0.94 and 0.06 among Tajiks, respectively. The frequency of the Sc1 allele was 1.00 in both Han and Tajik ethnic populations. The frequency of the Coa allele was 1.00 in Han, She, and Tajik ethnic populations.