Research progress on vesicle-associated membrane protein 8 / 中国生物制品学杂志

@#Membrane fusion is essential for all life activities of eukaryotes and the fusion process requires the interaction of different vesicular transporters,which are highly conserved in eukaryotes,to coordinate specifically and facilitate the fusion of different biofilms. Vesicle associated membrane protein 8(VAMP8)mainly locates in vesicular as well as lysosomal membranes,and plays a vital role in the fusion of many different biofilms. This paper focused on the molecular structure,transcriptional regulation,post-translational modification and biological function of VAMP8 as well as the research progress on its correlation with human diseases,so as to provide new ideas for the treatment of related diseases and the development of effective therapeutics targeting VAMP8.

Cellular endocytosis and exocytosis of soluble uranium and its damage to HK-2 cells / 中国辐射卫生

Objective To investigate the endocytosis and exocytosis of soluble uranium in human kidney proximal tubular epithelial (HK-2) cells and the cytotoxicity after uranium exposure. Methods Cell Counting Kit-8 assay was used to determine the cell viability after different concentrations of uranium exposure, and optical microscopy and transmission electron microscopy were used to observe the changes in cells after uranium exposure. Inductively coupled plasma mass spectrometry was used to monitor the endocytosis and exocytosis of uranium over time by cells. Flow cytometry was used to assess the changes in cell cycle and apoptosis after uranium exposure. Results After uranium exposure, HK-2 cells showed dose-dependent damage; cell cycle was arrested in G1 phase; cell apoptosis and necrosis occurred; cell proliferation was inhibited. The content of endocytic uranium increased gradually within 24 h, and there was a threshold for uranium endocytosis, while the fraction of uranium binding to cell surface was low (< 0.2%). Over 40% of the endocytic uranium would be exocytosed within 1 h. Uranium could form needle-like precipitates in both intracellular and extracellular areas after uranium exposure. Conclusion After uranium exposure, cells show decreased viability, cell cycle arrest, and cell apoptosis. The process of endocytosis and exocytosis of soluble uranium is very rapid. HK-2 cells can convert soluble uranium into non-toxic precipitates.

Effect of Sodium Salicylate on Calcium Currents and Exocytosis in Cochlear Inner Hair Cells: Implications for Tinnitus Generation / 神经科学通报·英文版

Sodium salicylate is an anti-inflammatory medication with a side-effect of tinnitus. Here, we used mouse cochlear cultures to explore the effects of salicylate treatment on cochlear inner hair cells (IHCs). We found that IHCs showed significant damage after exposure to a high concentration of salicylate. Whole-cell patch clamp recordings showed that 1-5 mmol/L salicylate did not affect the exocytosis of IHCs, indicating that IHCs are not involved in tinnitus generation by enhancing their neuronal input. Instead, salicylate induced a larger peak amplitude, a more negative half-activation voltage, and a steeper slope factor of Ca2+ current. Using noise analysis of Ca2+ tail currents and qRT-PCR, we further found that salicylate increased the number of Ca2+ channels along with CaV1.3 expression. All these changes could act synergistically to enhance the Ca2+ influx into IHCs. Inhibition of intracellular Ca2+ overload significantly attenuated IHC death after 10 mmol/L salicylate treatment. These results implicate a cellular mechanism for tinnitus generation in the peripheral auditory system.

The role of the exocyst in renal ciliogenesis, cystogenesis, tubulogenesis, and development

The exocyst is a highly conserved eight-subunit protein complex (EXOC1–8) involved in the targeting and docking of exocytic vesicles translocating from the trans-Golgi network to various sites in renal cells. EXOC5 is a central exocyst component because it connects EXOC6, bound to the vesicles exiting the trans-Golgi network via the small GTPase RAB8, to the rest of the exocyst complex at the plasma membrane. In the kidney, the exocyst complex is involved in primary ciliognesis, cystogenesis, and tubulogenesis. The exocyst, and its regulators, have also been found in urinary extracellular vesicles, and may be centrally involved in urocrine signaling and repair following acute kidney injury. The exocyst is centrally involved in the development of other organs, including the eye, ear, and heart. The exocyst is regulated by many different small GTPases of the RHO, RAL, RAB, and ARF families. The small GTPases, and their guanine nucleotide exchange factors and GTPase-activating proteins, likely give the exocyst specificity of function. The recent development of a floxed Exoc5 mouse line will aid researchers in studying the role of the exocyst in multiple cells and organ types by allowing for tissue-specific knockout, in conjunction with Cre-driver mouse lines.

Protein kinase A inhibition induces EPAC-dependent acrosomal exocytosis in human sperm / 亚洲男科学杂志(英文版)

To interact with the egg, the spermatozoon must undergo several biochemical and motility modifications in the female reproductive tract, collectively called capacitation. Only capacitated sperm can undergo acrosomal exocytosis, near or on the egg, a process that allows the sperm to penetrate and fertilize the egg. In the present study, we investigated the involvement of cyclic adenosine monophosphate (cAMP)-dependent processes on acrosomal exocytosis. Inhibition of protein kinase A (PKA) at the end of capacitation induced acrosomal exocytosis. This process is cAMP-dependent; however, the addition of relatively high concentration of the membrane-permeable 8-bromo-cAMP (8Br-cAMP, 0.1 mmol l-1) analog induced significant inhibition of the acrosomal exocytosis. The induction of acrosomal exocytosis by PKA inhibition was significantly inhibited by an exchange protein directly activated by cAMP (EPAC) ESI09 inhibitor. The EPAC selective substrate activated AE at relatively low concentrations (0.02-0.1 μmol l-1), whereas higher concentrations (>5 μmol l-1) were inhibitory to the AE induced by PKA inhibition. Inhibition of PKA revealed about 50% increase in intracellular cAMP levels, conditions under which EPAC can be activated to induce the AE. Induction of AE by activating the actin severing-protein, gelsolin, which causes F-actin dispersion, was inhibited by the EPAC inhibitor. The AE induced by PKA inhibition was mediated by phospholipase C activity but not by the Ca2+-channel, CatSper. Thus, inhibition of PKA at the end of the capacitation process induced EPAC/phospholipase C-dependent acrosomal exocytosis. EPAC mediates F-actin depolymerization and/or activation of effectors downstream to F-actin breakdown that lead to acrosomal exocytosis.

Progress in synaptic mechanism in epileptogenesis / 中南大学学报(医学版)

Recurrent seizures lead to abnormal expression of synaptic proteins,reorganization of synapse and formation of abnormal neuron network.Recently,it is identified that the synaptic proteins are involved in epileptogenesis.The abnormal expression of several synaptic regulatory proteins and postsynaptic membrane receptor proteins may result in epilepsy.The ion channels usually are the action target of most antiepileptic drugs.However,carbamazepine and zonisamide may interact with syntaxin and/or soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex to exert its function of anti-epilepsy.The synaptic vesicle protein 2A is the action target for new anti-epileptic drugs,including levetiracetam,brivaracetam and seletracetam.

The role of Synaptotagmin1 in mouse oocyte fertilization / 天津医药

@#Objective To investigate the dynamics of cortical granules exocytosis (CGE), and the role of Synaptotagmin1 (Syt1) in mouse fertilization. Methods The dynamics of mouse CGE were filmed on Perkin Elmer precisely Ulta VIEW VOX confocal Imaging System. The Syt1 functions on mouse fertilization and expression in zygotes were analyzed by immunofluorescence, Western blot assy and qRT-PCR. Results The dynamic process of mouse CGE was observed after oocyte activation, and the exact pot seems to be close to the polar body. The Syt1 expression was gradually increased after fertilization. The mouse fertilization rate after Syt1 knockdown was significantly lower than that of the control group (P＜ 0.05). Conclusion The dynamic process of CGE is studied. It is found that Syt1 is involved in mouse fertilization process.

The effect of pH and ligand density on the endocytosis and exocytosis process of FcBP decorated PEG-PCL micelles on Caco-2 cells / 药学学报

The difference in pH between apical and basolateral side of intestinal epithelial and pH dependence character of the combination of FcRn (neonatal Fc receptor) and ligand might improve the delivery of hydrophobic drugs by facilitating the transcytosis of nanocarriers. Here we designed FcBP (IgG Fc domain-binding peptides) decorated coumarin 6 (C6) loaded poly(ethyl ethylene phosphate)-co-poly(ε-caprolactone) (PEG-PCL) micelles with different ligand densities to study the effect of pH and ligand density on the endocytosis and exocytosis process of micelles on human colon adenanocaricinoma cell lines (Caco-2). Active micelles with different ligand densities and passive micelles were prepared using the thin-film hydration method. The size of the micelles was characterized by dynamic light scattering analysis and the morphology was observed by transmission electron microscope. The endocytosis and exocytosis of the micelles at pH 7.4 and pH 6.0, as well as the effect of FcRn on the endocytosis, were investigated by flow cytometry. The results showed that the size of micelles was about 30 nm, which was not affected by FcBP decoration. We found that pH and ligand density could both influence the endocytosis. The uptake of active micelles was higher at pH 6.0 than at pH 7.4, and an optimal ligand density of endocytosis was appeared in both pH environment. Then we proved that FcBP decorated micelles could be endocytosed at pH 6.0 and exocytosed at pH 7.4, and the exocytosis process was also related to ligand density. Micelles with 10% ligand density had the largest exocytosis, showing the potentiality to deliver drugs through the intestinal epithelial. In addition, the competitive inhibition experiments illustrated that the interaction between FcRn and FcBP were essential to endocytosis. The results will enhance the understanding on the FcBP decorated PEG-PCL micelles for transmemberane drug delivery.

Research progress on the roles of lysosome in the evolution of cancer / 中国医师杂志

Lysosomes are acidic catabolic organelles,containing over 50 acid hydrolases and many lysosomal specific membrane proteins.Lysosomes are responsible for the disposal and recycling of worn out and damaged cellular macromolecules and organelles as well as the digestion of extracellular and foreign materials delivered to them by endocytosis,autophagy and phagocytosis.Increased expression and function of various lysosomal hydrolases are common in human tumors,and they often correlate with a higher risk of rccurrence and poor prognosis.Inhibition of lysosomal exocytosis can inhibit tumor invasion and metastasis.It does not affect the activity of acid hydrolytic enzymes,but causes the instability of lysosomal membrane and increases the sensitivity of tumor cells to drugs.

Insulin replacement restores the vesicular secretory apparatus in the diabetic rat lacrimal gland / Reposição de insulina restaura o mecanismo secretório da glândula lacrimal de ratos diabéticos

ABSTRACT Purpose: In the lacrimal gland (LG) acinar cells, signaling regulates the release of secretory vesicles through specific Rab and SNARE exocytotic proteins. In diabetes mellitus (DM), the LGs are dysfunctional. The aim of this work was to determine if secretory apparatus changes were associated with any effects on the secretory vesicles (SV) in diabetic rats as well as the expression levels of constituent Rab and members of the SNARE family, and if insulin supplementation reversed those changes. Methods: DM was induced in male Wistar rats with an intravenous dose of streptozotocin (60 mg/kg). One of the two diabetic groups was then treated every other day with insulin (1 IU). A third control group was injected with vehicle. After 10 weeks, Western blotting and RT-PCR were used to compared the Rab and SNARE secretory factor levels in the LGs. Transmission electron microscopy evaluated acinar cell SV density and integrity. Results: In the diabetes mellitus group, there were fewer and enlarged SV. The Rab 27b, Rab 3d, and syntaxin-1 protein expression declined in the rats with diabetes mellitus. Insulin treatment restored the SV density and the Rab 27b and syntaxin expression to their control protein levels, whereas the Vamp 2 mRNA expression increased above the control levels. Conclusions: Diabetes mellitus LG changes were associated with the declines in protein expression levels that were involved in supporting exocytosis and vesicular formation. They were partially reversed by insulin replacement therapy. These findings may help to improve therapeutic management of dry eye in diabetes mellitus. .

RESUMO Objetivo: Células acinares da glândula lacrimal (GL) sinalizam a regulação da liberação através de vesículas secretórias específicas Rab proteínas exocitóticas SNARE. No diabetes mellitus (DM), as glândulas lacrimais são disfuncionais. O objetivo deste trabalho foi determinar se em ratos diabéticos, alterações dos aparatos secretórios estão associados a efeitos sobre vesículas secretoras (VS) e sobre os níveis de expressão do constituinte Rab, bem como membros da família SNARE, e se a suplementação de insulina reverte as alterações. Métodos: DM foi induzido em ratos Wistar machos com uma dose intravenosa de estreptozotocina (60 mg/kg). Um dos dois grupos diabéticos foi então tratado a cada dois dias com insulina (1 UI). Um terceiro grupo controle foi injetado com o veículo. Após 10 semanas, western blot e RT-PCR comparou níveis de fatores secretórios de Rab e SNARE na glândula lacrimal. Microscopia eletrônica de transmissão (MET) avaliaram a densidade e integridade de VS de célula acinar. Resultados: No grupo diabetes mellitus , houve poucas e alargadas VS. Rab27b, Rab 3d e Sintaxina-1 diminuiu a expressão da proteína em ratos com Diabetes Mellitus. O tratamento com insulina restaurou a densidade das VS e expressão de Rab 27b e Sintaxina para seus níveis de proteína controle, enquanto a expressão de Vamp 2 RNAm aumentou em relação aos controles. Conclusões: Alterações na glândula lacrimal de diabetes mellitus estão associadas a reduções nos níveis de expressão de proteínas envolvidas no apoio a exocitose e formação vesicular. Eles são, em parte, revertida por terapia de reposição de insulina. Estes resultados podem ajudar a melhorar a conduta terapêutica do olho seco no diabetes mellitus. .

Regulation of Mucin Exocytosis in Airway Secretory Cells / 대한이비인후과학회지

Mucin secretion in the airway epithelium acts as an essential barrier process that protects the upper respiratory tract from inhaled particles, environmental pathogens and toxicants. However, dysregulated mucin secretion contributes to pathophysiologic conditions such as rhinitis, asthma, and chronic obstructive pulmonary disease etc. The study on mucin hypersecretion has long been worked, but the exact molecular composition and mechanism for exocytic machinery remain mostly to be elucidated. The regulated mucin secretion, highly coordinated process, is mediated by the cooperative interaction of several proteins existing in the secretory granule, cytoplasm, and plasma membrane. This review provides the information on molecular components of the core exocytic machinery and their functional roles for mucin exocytosis in airway secretory cells.

Regulación de la liberación de serotonina en distintos compartimientos neuronales / Regulation of serotonin release from different neuronal compartments

Serotonin is fundamental for the modulation of social behavior, emotions and a wide variety of physiological functions. The functions of serotonergic systems have been highly conserved along the evolutionary scale and in general small numbers of neurons innervate virtually all the nervous system, and exert multiple effects depending on the site of release. Synaptic pools produce fast and local effects, while extrasynaptic pools in the soma, dendrites, axons and the periphery of synapses produce diffuse effects, characteristic of mood modulation. Serotonin release from synaptic terminals is produced by exocytosis of small clear vesicles and is activated by single or low-frequency impulses, while increases in the stimulation frequency produce synaptic facilitation and depression. In contrast, release from the soma is produced by exocytosis of dense-cored vesicles and requires stimulation at high frequencies, the activation of L-type calcium channels and calcium-induced calcium release from intracellular stores. Serotonin released from the presynaptic terminals immediately activates auto-receptors in the same terminals, locally decreasing the subsequent excitability, firing frequency and release. Differential regulation of serotonin release in different cell compartments allows the same neuron to produce different types of effects depending on the firing rate.

La serotonina es fundamental para la modulación de la conducta social, las emociones y una gran cantidad de funciones fisiológicas. La función de los sistemas serotonérgicos se ha conservado a lo largo de la escala evolutiva y, en general, números pequeños de neuronas inervan prácticamente todo el Sistema Nervioso. Estas neuronas son capaces de ejercer múltiples efectos, dependiendo de si liberan serotonina de pozas sinápticas, que ejercen efectos rápidos y locales o de pozas extrasinápticas en la periferia de las sinapsis, el axon, el cuerpo celular o las dendritas, con lo que se producen efectos lentos y difusos, característicos de los estados de ánimo. La liberación de serotonina en las terminales sinápticas es producida por la exocitosis de vesículas claras pequeñas y se activa con impulsos sencillos o a baja frecuencia. La estimulación con trenes de impulsos a frecuencias crecientes produce facilitación y depresión sináptica. En contraste, la liberación a partir del soma es producida por la exocitosis de vesículas de núcleo denso y requiere de la estimulación a frecuencias altas, la activación de canales de calcio tipo L y de la liberación de calcio de los depositos intracelulares. La serotonina liberada por las terminales sinápticas activa de manera inmediata autorreceptores en las propias terminales que la liberaron, disminuyendo la excitabilidad subsiguiente y, por lo tanto, la frecuencia de disparo y la liberación de manera localizada. La regulación diferencial de la liberación en cada compartimiento celular permite que la misma neurona produzca diferentes tipos de efectos dependiendo de la frecuencia de disparo.

Intracellular Ca2+ Mobilization and Beta-hexosaminidase Release Are Not Influenced by 60 Hz-electromagnetic Fields (EMF) in RBL 2H3 Cells

The effects of extremely low frequency electromagnetic fields (EMF) on intracellular Ca2+ mobilization and cellular function in RBL 2H3 cells were investigated. Exposure to EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h did not produce any cytotoxic effects in RBL 2H3 cells. Melittin, ionomycin and thapsigargin each dose-dependently increased the intracellular Ca2+ concentration. The increase of intracellular Ca2+ induced by these three agents was not affected by exposure to EMF (60 Hz, 1 mT) for 4 or 16 h in RBL 2H3 cells. To investigate the effect of EMF on exocytosis, we measured beta-hexosaminidase release in RBL 2H3 cells. Basal release of beta-hexosaminidase was 12.3+/-2.3% in RBL 2H3 cells. Exposure to EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h did not affect the basal or 1 microM melittin-induced beta-hexosaminidase release in RBL 2H3 cells. This study suggests that exposure to EMF (60 Hz, 0.1 or 1 mT), which is the limit of occupational exposure, has no influence on intracellular Ca2+ mobilization and cellular function in RBL 2H3 cells.

Topographical Propagation of alpha-synuclein Pathology in Parkinson's Disease: Phenomenology and Hypothetical Mechanism

Parkinson's disease is an age-related, slowly progressing neurodegenerative disorder characterized by abnormal deposition of aggregated alpha-synuclein in neuronal cell bodies (Lewy bodies) and neurites (Lewy neurites), as well as in glia. Based on semiquantitative assessment of Lewy pathologies in autopsy samples, a staging system was proposed indicating a highly predictable sequence of pathological progression. This staging system implicates a propagation of alpha-synuclein aggregation throughout the brain with an ascending pattern from lower brain stem to neocortex. The underlying mechanism for the pathological propagation is unknown. However, the recent discoveries on the secretion of neuronal alpha-synuclein and subsequent uptake of the protein by neighboring cells propose an interneuronal transmission of alpha-synuclein aggregates as a novel mechanism for the spread of Lewy pathology in PD. Elucidation of this mechanism is likely to identify novel therapeutic strategies that halt the progression of PD.

Expression of Ca2+-dependent Synaptotagmin Isoforms in Mouse and Rat Parotid Acinar Cells

Synaptotagmin is a Ca2+ sensing protein, which triggers a fusion of synaptic vesicles in neuronal transmission. Little is known regarding the expression of Ca2+ - dependent synaptotagmin isoforms and their contribution to the release of secretory vesicles in mouse and rat parotid acinar cells. We investigated a type of Ca2+ - dependent synaptotagmin and Ca2+ signaling in both rat and mouse parotid acinar cells using RT-PCR, microfluorometry, and amylase assay. Mouse parotid acinar cells exhibited much more sensitive amylase release in response to muscarinic stimulation than did rat parotid acinar cells. However, transient [Ca2+]i increases and Ca2+ influx in response to muscarinic stimulation in both cells were identical, suggesting that the expression or activity of the Ca2+ sensing proteins is different. Seven Ca2+ - dependent synaptotagmins, from 1 to 7, were expressed in the mouse parotid acinar cells. However, in the rat parotid acinar cells, only synaptotagmins 1, 3, 4 and 7 were expressed. These results indicate that the expression of Ca2+ - dependent synaptotagmins may contribute to the release of secretory vesicles in parotid acinar cells.

Effect about Neurite Extension of FS390, an Inhibitor of Exocytosis in Rat Hippocampal Neurons and PC12 Cells / 대한해부학회지

FS390, a novel microbial metabolite from Streptomyces spp. was identified as a small molecular substance and shown a inhibition activities for the release of neurotransmitter from rat hippocampal neuron and PC12 cells. FS390 is an inhibitor of trifiated norepinephrine ([3H]-NE) release in high K+ buffer solution containing ionomycin, indicating that FS390 inhibits neurotransmitter release after the influx of Ca2+ ions. When examined the effect of FS390 on beta-glucuronidase release from guinea pig neurophils, FS390 inhibited beta-glucuronidas release: when treated with 5 microgram/mL of FS390, which was not induced cellular cytotoxicity. The fact that the beta-glucuronidase release in neutrophil and norepinephrine release in neuron was inhibited suggests the similarity in the locations and the mechanisms of FS390 action targets. When treated with 5 microgram/mL of FS390, [3H]-NE release and neurite extension for both rat hippocampal neurons and PC12 cells were prevented. These observations of FS390 functioning as an inhibitor of neurotransmitter release suggest that FS390 has an important role in synaptic transmission in neuron.

Screening of Low Molecular Metabolite, FS390 as an Inhibitor of Neurotransmitter Release from PC12 Cells / 대한해부학회지

We established an in vitro experimental system using the following procedure. We first introduced tritium-labeled norepinephrine ([3H]-NE) into PC12 cells. The [3H]-NE incorporated-PC12 cells were stimulated by a high concentration (60 mM) of K+ buffer during 12 minutes. Then, we collected 100 microliter supernatant and counted the amount of [3H]-NE release from PC12 cells with a scintillation counter. After screening fungal, Streptomyces spp. or bacterial product using this experimental sytem, we obtained FS390 from Streptomyces spp. which inhibited [3H]-NE release from PC12 cells. FS390 also inhibits the release of ATP as a neurotransmitter of PC12 cells and rat cortical neurons. The inhibitory effect was seen even when the PC12 cells were treated with low K+ buffer containing ionomycin (1 micrometer) as an ionopore. This result suggests that the inhibitory action of FS390 on neurotransmitter release appeared after the influx of Ca2+.

Anti-sense RNA Inhibits the Expression of Synaptotagmin Ⅱ in RBL-2H3 and Enhances the Exocytosis of Lysosomes in RBL-2H3 / 华中科技大学学报（医学）（英德文版）

The expression of synaptotagmin Ⅱ (Syt2) in RBL-2H3 (RBL) and its role during exocytosis of RBL was investigated. The expression of Syt2 in RBL was detected by western blot and Syt2 gene was amplified by PCR. The anti-sense full length Syt2 cDNA expression vector was constructed with pEGFP-N1 and transfected into RBL by electroporation, and stable transfectants were selected by using G418. To analyze the role of Syt2 during exocytosis of RBL, the release of cathepsin D was assayed by immunoblotting. The results showed that Syt2 was expressed in RBL.The anti-sense expression vector pEGFP-N1-Syt2-AS was constructed and the sequence of insertion was completely consistent with rat Syt2 (accession number in GeneBank: NM012665). The stable transfectants (RBL-Syt2-AS) were obtained. Western blot showed that RBL-Syt2-AS expressed a lower level of Syt2 (8 % and 10 % of control cells), indicating that the expression of Syt2 in RBLSyt2-AS was markedly down-regulated by anti-RNA. Compared with control, the release of cathepsin D by RBL-Syt2-AS was increased. It was concluded that Syt2 expressed in RBL and could inhibit exocytosis of lysosomes in RBL.

Early phase of amyloid beta42-induced cytotoxicity in neuronal cells is associated with vacuole formation and enhancement of exocytosis

Amyloid beta (Abeta) neurotoxicity is believed to play a critical role in the pathogenesis of Alzheimer's disease (AD) mainly because of its deposition in AD brain and its neuronal toxicity. However, there have been discrepancies in Abeta-induced cytotoxicity studies, depending on the assay methods. Comparative analysis of Abeta42-induced in vitro cytotoxicity might be useful to elucidate the etiological role of Abeta in the pathogenesis of AD. In this study, MTT, CCK-8, calcein-AM/EthD-1 assays as well as thorough microscopic examinations were comparatively performed after Abeta42 treatment in a neuronal precursor cells (NT2) and a somatic cells (EcR293). Extensive formation of vacuoles was observed at the very early stage of Abeta42 treatment in both cells. Early observation of Abeta42 toxicity as seen in vacuole formation was also shown in MTT assay, but not in CCK-8 and calcein-AM/EthD-1 assays. In addition, Abeta42 treatment dramatically accelerated MTT formazan exocytosis, implying its effect on the extensive formation of cytoplasmic vacuoles. Abeta42 seems to cause indirect inhibition on the intracellular MTT reduction as well as vacuole formation and exocytosis enhancement. Following the acute cellular dysfunction induced by Abeta42, the prolonged treatment of micromolar concentration of Abeta42 resulted in slight inhibition on redox and esterase activity. The early Abeta42-induced vacuolated morphology and later chronic cytotoxic effect in neuronal cell might be linked to the chronic neurodegeneration caused by the accumulation of Abeta42 in AD patients' brain.

Organophosphorus pesticide-induced immunotoxicity and its updated mechanisms / 医学研究生学报

Organophosphorus pesticides(OP) are used as insecticides in agriculture throughout the world.The main toxicity of OP is neurotoxicity,which is caused by the inhibition of acetylcholinesterase.OPs also affect the immune response and suppress antibody production,T cell proliferation and the activity of natural killer(NK) cells and cytotoxic T lymphocytes(CTL).However,there have been few studies on the mechanism of OP-induced immunotoxicity,especially the mechanism of OP-induced inhibition of the cytolytic activity of killer cells.This study updates the mechanisms of pesticide-induced immunotoxicity,including its direct and indirect effects on the immune system.