• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Rab27a/Slp2-a complex is involved in Schwann cell myelination

    2016-02-09 05:17:20WenfengSuYunGuZhongyaWeiYuntianShenZihanJinYingYuanXiaosongGuGangChenJiangsuKeyLaboratoryofNeuroregenerationCoinnovationCenterofNeuroregenerationNantongUniversityNantongJiangsuProvinceChinaAffiliatedHospitalofNanton

    Wen-feng Su, Yun Gu, Zhong-ya Wei, Yun-tian Shen, Zi-han Jin, Ying Yuan,, Xiao-song Gu, Gang Chen, Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China Affiliated Hospital of Nantong University, Nantong, Jiangsu Province, China

    Rab27a/Slp2-a complex is involved in Schwann cell myelination

    Wen-feng Su1, Yun Gu1, Zhong-ya Wei1, Yun-tian Shen1, Zi-han Jin1, Ying Yuan1,2, Xiao-song Gu1, Gang Chen1,*
    1 Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
    2 Affiliated Hospital of Nantong University, Nantong, Jiangsu Province, China

    How to cite this article:Su WF, Gu Y, Wei ZY, Shen YT, Jin ZH, Yuan Y, Gu XS, Chen G (2016) Rab27a/Slp2-a complex is involved in Schwann cell myelination. Neural Regen Res 11(11):1830-1838.

    Open access statement:This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.

    Funding:This study was supported by the National Natural Science Foundation of China, No. 31071251, 81471255, and 81471259; a grant from the Ministry of Science and Technology of China (973 Program), No. 2014CB542202; a grant from the Basic Research Program of Education Department of Jiangsu Province, China, No. 14KJA310004; a grant from the Natural Science Research Project of Nantong Science and Technology Bureau, China, No. HS2013014; and a grant from the Natural Science Research Project of Nantong University, China, No. 13Z008.

    Graphical Abstract

    Myelination of Schwann cells in the peripheral nervous system is an intricate process involving myelin protein trafficking. Recently, the role and mechanism of the endosomal/lysosomal system in myelin formation were emphasized. Our previous results demonstrated that a small GTPase Rab27a regulates lysosomal exocytosis and myelin protein trafficking in Schwann cells. In this present study, we established a dorsal root ganglion (DRG) neuron and Schwann cell co-culture model to identify the signals associated with Rab27a during myelination. First, Slp2-a, as the Rab27a effector, was endogenously expressed in Schwann cells. Second, Rab27a expression significantly increased during Schwann cell myelination. Finally, Rab27a and Slp2-a silencing in Schwann cells not only reduced myelin protein expression, but also impaired formation of myelin-like membranes in DRG neuron and Schwann cell co-cultures. Our findings suggest that the Rab27a/ Slp2-a complex affects Schwann cell myelinationin vitro.

    nerve regeneration; Schwann cells; dorsal root ganglion neurons; co-culture; myelin proteins; myelination; Rab27 effectors; Rab27a; Slp2-a; neural regeneration

    Introduction

    The myelin sheath in the peripheral nervous system (PNS) comprises a specialized Schwann cell plasma membrane, which serves to increase axonal impulse conduction (da Silva et al., 2014; Luo et al., 2014; Nave and Werner, 2014; Miyamoto et al., 2016; Taveggia, 2016). Clinically, abnormal myelination is a feature of many peripheral neuropathies that can cause abnormal electrical signal conduction and lead to secondary axonal injury (Duncan et al., 2014; Gonzalez et al., 2016; Klein and Martini, 2016; Kondo and Duncan, 2016; Schulz et al., 2016). The proper synthesis and transport of myelin proteins is important for myelin biogenesis (Kwon et al., 2013; Heller et al., 2014; Montani et al., 2014; Domènech-Estévez et al., 2015; G?kbuget et al., 2015).However, the mechanisms regulating myelin protein trafficking remain poorly understood (White and Kr?mer-Albers, 2014; Salzer, 2015; Ma et al., 2016; Rao and Pearse, 2016).

    Recently, the role and mechanisms of the endosomal/lysosomal system in myelin formation were investigated (Trajkovic et al., 2006; Prolo et al., 2009; Feldmann et al., 2011; Shen et al., 2016). Neuronal signals induce exocytose is of the proteolipid protein (PLP) from late endosome/lysosome membranes stored into the plasma membrane (Trajkovic et al., 2006; Shen et al., 2016). Consistent with this finding, myelin abnormalities are a very common phenomenon in many lysosomal storage diseases, including multiple sulfatase deficiency, globoid cell leukodystrophy, and metachromatic leukodystrophy (Faust et al., 2010; Marsden and Levy, 2010). Because lysosomes serve dual functions in many cell types–the degradation of proteins and storage of synthesized secretory products (Blott and Griffiths, 2002; de Duve, 2005; Zhang et al., 2007; Johnson et al., 2013; Kim et al., 2013; Hou et al., 2015; Shimada-Sugawara et al., 2015)–the concept of secretory lysosomes was proposed.

    Previous studies have shown that the Rab27 subfamily and their multiple effectors play a critical role in regulating lysosome-related organelle exocytosis (Izumi, 2007; Johnson et al., 2013; Shimada-Sugawara et al., 2015; Yamaoka et al., 2015b, a). Additionally, our previous results showed that Rab27a participates in lysosomal exocytosis and myelin protein P0 trafficking in Schwann cells. Furthermore, Rab27a-deficient ashen mice demonstrate impaired demyelination of the injured sciatic nerve (Chen et al., 2012). In this study, we further investigated the mechanisms of Rab27a in the regulation of Schwann cell myelination by the dorsal root ganglion (DRG) neuron and Schwann cell co-culture system as a model of myelination.

    Material and Methods

    Culture, isolation, and purification of Schwann cells

    Animal protocols were reviewed and approved by the Animal Ethics Committee of Nantong University, China (license No. 2014-0001), and the experimental protocol was in accordance with the Guide for the Care and Use of Laboratory Animals (National Institutes of Health Publication, No. 80-23). Precautions were taken to minimize suffering and the number of animals used in each experiment.

    Primary cultures of Schwann cells were prepared as previously described (Brockes et al., 1981; Chen et al., 2012). In brief, Schwann cells were harvested from sciatic nerves of 1–3-day-old Sprague-Dawley rats (Experimental Animal Center of Nantong University, Nantong, Jiangsu Province, China, SPF level, no gender requirement). To inhibit fast proliferation of fibroblasts, the Schwann cell purification medium was replaced (Table 1) for 1 day, followed by a 1-day recovery period in growth factor-free medium, then refreshed with Schwann cell growth medium. About 7 days later, when the Schwann cell cultures reached confluence, complement-mediated immune cytolysis was performed to eliminate fibroblasts by incubating the cells in 4 μg/mL of anti-Thy-1.1 antibody (Sigma-Aldrich, St. Louis, MO, USA) for 2 hours on ice and then with 1 mL of rabbit complement (Gibco, Carlsbad, CA, USA) for 1 hour at 37°C. Afterwards, > 98% pure Schwann cells were obtained and the purity was determined by immunocytochemistry.

    Culture, isolation, and purification of DRG neurons

    DRG neurons were isolated by dissection from embryos of 14.5-day pregnant Sprague-Dawley rats (Experimental Animal Center of Nantong University, Nantong, Jiangsu Province, China. SPF level). One DRG explant was placed into each poly-D-lysine (PDL) (Invitrogen)-coated tissue culture well (24-well dishes, glass cover slips covered with 10 μg/mL PDL before use) along with high-glucose Dulbecco’s-modified Eagle’s medium (DMEM-HG) (Gibco) containing 10% fetal bovine serum (FBS) (Gibco) and the cells were allowed to adhere for 24 hours. The medium was then replaced with DRG purification medium (Table 1) and the non-neuronal cells were eliminated by incubating for 3 days in DRG purification medium. The medium was then replaced with DRG growth medium followed by the addition of purified Schwann cells.

    Co-culture of DRG neurons and Schwann cells

    The DRG neuron and Schwann cell co-culture system was prepared as previously described (Eldridge et al., 1989). Briefly, purified Schwann cells were co-cultured and growth factors were removed at 4 hours prior to plating on DRG neurons. Then, 0.125% trypsin was used to digest Schwann cells into single cells, and 50,000 Schwann cells were added to each DRG neuron culture coverslip. DRG growth medium was changed 1 day before co-culture, and half of the original medium was discarded after co-culture. A total of 250 μL DMEM-HG containing 10% FBS was added to each well, and the cells were allowed to attach overnight. The DRG neuron and Schwann cell co-cultures were maintained in DRG growth medium for 2 days and then switched to differentiation medium for 4 days. Finally, the co-culture system was maintained in myelination medium to induce myelination. Half of the medium volume was changed every 2 days. After 3–4 days, myelin sheaths were present. In this co-culture process, several specific myelination stages were identified by immunocytochemistry and electron microscopy.

    siRNA transfection

    Schwann cells were transfected with siRNA using Lipofectamine? RNAi MAX complexes (Invitrogen) at 4 or 5 days post-purification. ON-TARGET plus Non-targeting control siRNA (catalog D-0018100-01-20, GE Dharmacon, Lafayette, CO, USA) served as the control. The siRNA primer sequences for Rab27a and siRNA Slp2-a are listed inTable 2.

    Real-time quantitative PCR assay

    Total RNAs were extracted using an RNeasy Mini Kit (Qiagen, Hilden, Germany) and cDNA was synthesized using a cDNA Reverse Transcription Kit (Applied Biosystems, Foster, CA, USA). Real-time quantitative PCR was performed using the 7300 Real-Time PCR System (Applied Biosystems). The primers used in this experiment are shown inTable 3.Levels of mRNA were normalized by glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a reference. All reactions were repeated in triplicate.

    Immunocytochemistry

    The culture medium was aspirated, and the cells were washed with PBS and then fixed with 4% paraformaldehyde (PFA) for 15 minutes at room temperature and methanol for 10 minutes at ?20°C. The non-specific antibody-binding sites were blocked with Immunol Staining Blocking Buffer (Beyotime, Haimen, Jiangsu Province, China) for 1 hour at room temperature, and then the cultures were incubated with primary antibody overnight at 4°C. Antibodies to the following proteins were used at the indicated concentrations: mouse anti-Rab27a (1:100; Abcam, Cambridge, MA, USA), rabbitanti-Slp2-a (1:200; Protein Tech, Chicago, IL, USA), mouse anti-MBP (1:200, Abcam), chicken anti-P0 (1:50; Novus, Littleton, CO, USA), rabbit anti-MAG (1:200; Sigma), and mouse anti-NF (1:600; Sigma). After washing 3 times in PBS to remove excess primary antibody, the cultures were incubated for 1 hour at room temperature with their respective fluorescence-conjugated secondary antibodies (Jackson Immuno Research, West Grove, PA, USA): goat anti-rabbit IgG-Cy3 (H + L), goat anti-mouse IgG-Cy3 (H + L), goat anti-rabbit IgG-Cy5 (H + L), goat anti-mouse IgG-Alexa-488 (H + L), goat anti-rabbit IgG-Alexa-488 (H + L), and goat anti-chicken IgG (H + L) rhodamine, all at a dilution of 1:1,000. After a final PBS washing, the stainings were imaged with a confocal microscope (TCS SP5; Leica Microsystems, Wetzlar, Germany).

    Electron microscopy

    The co-cultures were examined using electron microscopy at different stages as described (Einheber et al., 1995; Yuan et al., 2004). At the exact stage, the co-culture coverslips were fixed with precooled 2.5% glutaraldehyde (Sigma) and preserved at 4°C.

    Scanning electron microscopy

    The co-culture cells were washed with tannic acid and then post-fixed with 1% osmium tetraoxide solution (Sigma), dehydrated stepwise twice in increasing concentrations of ethanol and in Tert-butanol, and dried in a critical point drier (Hitachi, Tokyo, Japan). Subsequently, the samples were coated with gold in a JFC-1100 unit (Jeol Inc., Tokyo, Japan) and observed under a scanning electron microscope (JEM-T300, Jeol Inc.).

    Transmission electron microscopy

    The co-culture coverslips were embedded in 1% agar suitable for obtaining cross-sections of the cultures, post-fixed with 1% osmium tetraoxide solution (Sigma), dehydrated stepwise in increasing concentrations of ethanol, embedded in Epon 812 epoxy resin (Sigma), and cut into transverse sections. Then the ultra-thin transverse sections were stained with lead citrate and uranyl acetate. These sections were examined under a transmission electron microscope (Jeol Inc.).

    Western blot assay

    Protein was extracted from cultured cells with a buffer containing 1% sodium dodecyl sulfate (SDS, Sigma), 100 mM Tris-HCl, 1 mM phenylmethylsulfonyl fluoride (PMSF, Sigma), and 0.1 mM β-mercaptoethanol (Sigma). After centrifugation at 12,000 r/min for 5 minutes, the supernatant was collected and the protein concentration was determined. Protein extracts were heat denatured at 100°C for 5 minutes, electrophoretically separated on 8% or 12% SDS-PAGE, and transferred to polyvinylidene fluoride (PVDF) membranes (Thermo Fisher Scientific Pierce, Walthan, MA, USA). The membrane was probed with antibodies specific to Rab27a (mouse, 1,000, abcam), Slac2-b (goat, 1:200, SANTA CRUZ Inc., Paso Robles, CA, USA), Slac2-c (rabbit, 1:200, SANTA CRUZ Inc.), Slp2-a (rabbit, 1:800, Protein tech Group, Inc., Chicago, IL, USA), Slp3-a (rabbit, 1:200, Santa Cruz Inc.), Slp4 (rabbit, 1:500, Anbo, San Francisco, CA, USA), MAG (rabbit, 1:800, Sigma), P0 (chicken, 1:800, Novus, Littleton, CO, USA), and PMP22 (rabbit, 1:800, abcam) overnight at 4°C, followed by horseradish peroxidase (HRP)-conjugated secondary antibodies (1:1,000, Beyotime) for 1 hour at room temperature, and detected using the enhanced chemiluminescent substrate kit (ECL, Thermo Fisher Scientific Pierce, Walthan, MA, USA). The image was scanned with a GS800 Densitometer Scanner (Bio-Rad), and the data were analyzed using PDQuest 7.2.0 software (Bio-Rad). β-Actin (mouse, 1:5,000, Sigma) was used as an internal control (Gu et al., 2012; Wang et al., 2012).

    Immunoprecipitation

    Cultured Schwann cells were lysed in radioimmunoprecipitation assay (RIPA) buffer (Millipore, Billerica, MA, USA) and the lysates were incubated with 10 μg/mL mouse anti-Rab27a antibody (abcam) or mouse IgG control (abcam) on ice overnight with occasional shaking. The antibody-protein complexes were aggregated with Protein G-Agarose (Pierce) overnight on ice, with occasional shaking, and then centrifuged at 8,000 ×gfor 10 minutes. The pellet was washed for elimination of non-specific binding with 1 × RIPA buffer, eluted by 4 × SDS sample buffer without DL-dithiothreitol (DTT), boiled for 10 minutes, and then processed for western blotting.

    Statistical analysis

    All data are expressed as the mean ± SEM. Differences between two groups were compared using the Student’st-test. One-way analysis of variance followed by the Newman-Keuls test was used for the statistical analyses in other tests. The criterion for statistical significance wasP< 0.05.

    Results

    Identification of Slp2-a as Rab27a effector in Schwann cells

    Complement-mediated cytolysis with anti-Thy-1.1 antibody was used to purify cultured primary Schwann cells to remove contaminating of fibroblasts. To investigate endogenous expression of Rab27 protein family members in Schwann cells, real time-PCR and double staining were used to detect purified Schwann cells. As shown inFigure 1A–C,Schwann cells only expressed Rab27a protein, although real time-PCR results also showed weak Rab27b expression. Results are consistent with previous reports that Rab27a is primarily expressed outside the CNS and Rab27b is expressed in the central nervous system (Izumi, 2007). To identify the Rab27a effectors in Schwann cells, we analyzed mRNA expression of 11 different Rab27a/b effectors in Schwann cells according to a previous study (Izumi, 2007). As shown inFigure 1D, expressions of Slac2-b, Slac2-c, Slp2-a, Slp3-a, and Slp4 mRNA were readily visualized in Schwann cells. Western blotting identified high expression of only Slp2-a in Schwann cells (Figure 1E). Double Slp2-a and Rab27a immunostaining revealed co-localization of Slp2-a with Rab27a in cultured Schwann cells (Figure 1F). Additionally, co-immunoprecipitation experiments clearly showed an interaction between Slp2-a and Rab27a in cultured Schwann cells (Figure 1G). These results suggested that Slp2-a is endogenously expressed as a Rab27a effector in Schwann cells.

    Table 1 Different culture media for growth, purification, differentiation, and myelination of Schwann cells and dorsal root ganglion (DRG) neurons

    Table 3 Real time-PCR primers used for Rab27a/b effectors

    Table 2 siRNA primer sequences for Rab27a and siRNA Slp2-a

    Myelination model of DRG neurons co-cultured with Schwann cells

    Figure 1 Identification of Slp2-a as a Rab27a effector in cultured Schwann cells.

    Figure 2 Establishing a myelination model of DRG neurons co-cultured with Schwann cells.

    Figure 3 DRG neurons co-cultured with Schwann cells induce persistent up-regulation of Rab27a in Schwann cells.

    Figure 4 Rab27a and Slp2-a siRNA reduces Rab27a and Slp2-a expressions in cultured Schwann cells.

    Figure 5 Knockdown of Rab27a and Slp2-a in Schwann cells reduces myelin protein expression and myelin-like membrane formation in the DRG neuron and Schwann cell co-cultures.

    To examine the role of Rab27a and Slp2-a in Schwann cells on myelin formationin vitro, we established a myelination model of DRG neurons co-cultured with Schwann cells. Previous groups have successfully used this model to study PNS myelination (Johnson et al., 2001; Liu et al., 2005; Court et al., 2011). As shown inFigure 2, about 2 weeks after Schwann cells were added to the pure DRG neuron cultures, phase-contrast and fluorescence microscopy revealed myelin sheaths in the co-culture. Myelin sheaths were identifiable by the segregation structure in compact myelin sheaths under phase-contrast microscopy observation (Figure 2A) and the segregation of MAG-positive signalsby immunostaining (Figure 2B). Scanning electron microscopy (Figure 2C) revealed that Schwann cells surrounded the DRG neuronneurites and formed myelin segments, with a diameter longer than that of unmyelinated neurites. Transmission electron microscopy also showed the typical compact myelin structure (Figure 2D). Myelin protein expressions, including MAG, P0, and PMP22, were detected by western blotting at 1, 3, 7, 14, 21, 28, and 35 days after co-culture. Compared with purified Schwann cells, the DRG neuron and Schwann cell co-culture resulted in increased expression of all myelin proteins, which peaked at 35 days (Figure 2E). These results showed that a stable and reliablein vitromyelination model was established.

    Silencing of Rab27a and Slp2-a in the DRG neuron and Schwann cell co-culture reduces myelin protein expression and impairs formation of myelin-like membranes

    Using the DRG neuron and Schwann cell co-culture myelination model, we examined expression of Rab27a and Slp2-a at different time points following co-culture. As shown inFigure 3, western blot results showed significantly increased Rab27a expression at 3 days, which peaked at 7 days and remained increased at 13 days. However, Slp2-a expression remained unchanged after co-culture.

    Next, siRNA silencing of Rab27a and Slp2-a was used in Schwann cells to examine the roles of Rab27a and Slp2-a in myelination. First, the gene silencing efficiency of siRNA was detected using the same sequence of siRNA-Rab27a as our previous report (Chen et al., 2012), as well as three different siRNA-Slp2-a sequences. Gene silencing efficiency was then compared by real-time quantitative PCR. As shown inFigure 4A–C, siRNA dramatically reduced Rab27a and Slp2-a levels in Schwann cells. Among the three different sequences of Slp2-a siRNA, sequence #3 exhibited the strongest effect. Expressions of Rab27a and Slp2-a protein were analyzed in Schwann cells by western blotting. As shown inFigure 4D–F, Rab27a and Slp2-a protein expressions were dramatically reduced.

    Finally, purified Schwann cells were transfected with siRNA prior to seeding with DRG neurons, and then myelin protein mRNA levels and protein expressions were determined. As shown inFigure 5A–D, compared with the control group, Rab27a and Slp2-a knockdown significantly reduced both mRNA levels and protein expression of MAG, P0, and PMP22 after 14 days in co-culture. Furthermore, MBP immunostaining after 14 days of co-culture also showed that Rab27a or Slp2-a silencing impaired the formation of myelin-like membranes (Figure 5E,F). These results suggest that the Rab27a-Slp2-a complex plays an important role in Schwann cell myelination, especially in the early stage.

    Discussion

    The onset and maintenance of myelination in the PNS depends on myelin protein synthesis and transport (Salzer, 2015; Kondo and Duncan, 2016; Schulz et al., 2016; Taveggia, 2016). Our previous results indicate that Rab27a regulates lysosomal exocytosis and is involved in myelin protein trafficking in Schwann cells (Chen et al., 2012). This study aimed to identify the signals associated with Rab27a in Schwann cells. Our results demonstrated the importance of the Rab27a/Slp2-a complex in Schwann cell myelination. The underlying mechanism was determined through multiple experimental approaches, showing 1) Slp2-a was endogenously expressed as a Rab27a effector in Schwann cells; 2) thein vitroSchwann cell myelination model was established in our experiment; 3) Rab27a expression was significantly increased during Schwann cell myelination; 4) silencing of Rab27a and Slp2-a in Schwann cells not only reduced myelin protein expression, but also impaired the formation of myelin-like membranes in DRG neuron and Schwann cell co-cultures.

    Rab27a is associated with secretory lysosomes and intracellular protein trafficking (Blott and Griffiths, 2002; Izumi, 2007; Johnson et al., 2013; Catz, 2014; Ishida et al., 2014; Chen et al., 2015; Feng et al., 2016). It has been proposed that Rab27a regulates different membrane transport events by interacting with a different set of specific effectors (Li et al., 2014; Yasuda and Fukuda, 2014; Yamaoka et al., 2015a, 2016; Yasuda et al., 2015; Jiang et al., 2016; Kowluru, 2016; Netter et al., 2016). Three groups of Rab27a effectors from a total of 11 Rab27a/b effectors, including synaptotagmin-like protein (Slp), Slp homologue lacking C2 domains (Slac2), and Munc13-4, have been identified in mice and humans (Fukuda, 2005, 2013; Izumi, 2007; Ishida et al., 2014; Jiang et al., 2016; Kowluru, 2016; Netter et al., 2016). Results from the present study showed that Slp2-a and its binding effector Rab27a form a complex in Schwann cells. In general, Slp2-a can promote docking of Rab27a-containing vesicles to the plasma membrane in certain types of secretory cells (Kuroda and Fukuda, 2004; Saegusa et al., 2006; Holt et al., 2008; Ménasché et al., 2008; Fukuda, 2013; Yasuda and Fukuda, 2014; Yasuda et al., 2015). Although the Rab27a effector function of Slp2-a has been well established, the role of Slp2-a in myelination remains poorly understood. Results from the present study showed that Slp2-a silencing in Schwann cells not only reduced myelin protein expression, but also impaired formation of myelin-like membranes in the DRG neuron and Schwann cell co-cultures. The mechanisms responsible for decreased myelin protein expression by Rab27a and Slp2-a knockdown are not clear, but could be due to negative feedback of myelination.

    Thein vitromodel of rat DRG explant and Schwann cell co-cultures has been used in various studies (Johnson et al., 2001; Liu et al., 2005; Court et al., 2011; Liu and Chan, 2016) to determine the intrinsic molecular mechanisms responsible for myelination, including the complex regulation of transcription factors and myelin protein during myelin formation (Pereira et al., 2012; Salzer, 2015). In this study, we established a stable and reliablein vitromyelination model and transmission electron microscopy images confirmed the typical compact myelin structure. We also analyzed expression of several myelin proteins in this model using western blot analysis at different time points.

    Above all, this is the first demonstration that the Rab27a/Slp2-a complex affects Schwann cell myelinationin vitro. These findings show an interesting link between myelin biogenesis and lysosome-related organelle exocytosis, providing a basis for clinical treatments of demyelinating diseases.

    Acknowledgments:We are very grateful to Mr. Yul Huh from the Duke-NUS Medical School for instructive comments on the paper.

    Author contributions:WFS conceived the study, performed the experiments, and analyzed the data. YG designed the experiment; ZYW, YTS and ZHJ performed the experiment. GC, YG, YY and XSG formulated the hypotheses and reviewed the paper. GC and WFS wrote the paper. All authors approved the final version of the paper.

    Conflicts of interest:None declared.

    Plagiarism check:This paper was screened twice using CrossCheck to verify originality before publication.

    Peer review:This paper was double-blinded and stringently reviewed by international expert reviewers.

    Blott EJ, Griffiths GM (2002) Secretory lysosomes. Nat Rev Mol Cell Biol 3:122-131.

    Brockes JP, Fryxell KJ, Lemke GE (1981) Studies on cultured Schwann cells: the induction of myelin synthesis, and the control of their proliferation by a new growth factor. J Exp Biol 95:215-230.

    Catz SD (2014) The role of Rab27a in the regulation of neutrophil function. Cell Microbiol 16:1301-1310.

    Chen G, Zhang Z, Wei Z, Cheng Q, Li X, Li W, Duan S, Gu X (2012) Lysosomal exocytosis in Schwann cells contributes to axon remyelination. Glia 60:295-305.

    Chen TC, Hsieh CH, Sarnow P (2015) Supporting Role for GTPase Rab27a in Hepatitis C Virus RNA Replication through a Novel miR-122-Mediated Effect. PLoS Path 11:e1005116.

    Court FA, Zambroni D, Pavoni E, Colombelli C, Baragli C, Figlia G, Sorokin L, Ching W, Salzer JL, Wrabetz L, Feltri ML (2011) MMP2–9 cleavage of dystroglycan alters the size and molecular composition of Schwann cell domains. J Neurosci 31:12208-12217.

    da Silva TF, Eira J, Lopes AT, Malheiro AR, Sousa V, Luoma A, Avila RL, Wanders RJA, Just WW, Kirschner DA, Sousa MM, Brites P (2014) Peripheral nervous system plasmalogens regulate Schwann cell differentiation and myelination. J Clin Invest 124:2560-2570.

    de Duve C (2005) The lysosome turns fifty. Nat Cell Biol 7:847-849.

    Domènech-Estévez E, Baloui H, Repond C, Rosafio K, Médard JJ, Tricaud N, Pellerin L, Chrast R (2015) Distribution of monocarboxylate transporters in the peripheral nervous system suggests putative roles in lactate shuttling and myelination. J Neurosci 35:4151-4156.

    Duncan LE, Holmans PA, Lee PH, O’Dushlaine CT, Kirby AW, Smoller JW, ?ngür D, Cohen BM (2014) Pathway analyses implicate glial cells in schizophrenia. PLoS One 9:e89441.

    Einheber S, Hannocks MJ, Metz CN, Rifkin DB, Salzer JL (1995) Transforming growth factor-beta 1 regulates axon/Schwann cell interactions. J Cell Biol 129:443-458.

    Eldridge CF, Bunge MB, Bunge RP (1989) Differentiation of axon-related Schwann cells in vitro: II. Control of myelin formation by basal lamina. J Neurosci 9:625-638.

    Faust PL, Kaye EM, Powers JM (2010) Myelin lesions associated with lysosomal and peroxisomal disorders. Expert Rev Neurother 10:1449-1466.

    Feldmann A, Amphornrat J, Sch?nherr M, Winterstein C, M?bius W, Ruhwedel T, Danglot L, Nave KA, Galli T, Bruns D, Trotter J, Kr?mer-Albers EM (2011) Transport of the major myelin proteolipid protein is directed by VAMP3 and VAMP7. J Neurosci 31:5659-5672.

    Feng F, Jiang Y, Lu H, Lu X, Wang S, Wang L, Wei M, Lu W, Du Z, Ye Z, Yang G, Yuan F, Ma Y, Lei X, Lu Z (2016) Rab27A mediated by NF-κB promotes the stemness of colon cancer cells via up-regulation of cytokine secretion. Oncotarget doi: 10.18632/oncotarget.11454.

    Fukuda M (2005) Versatile role of Rab27 in membrane trafficking: focus on the Rab27 effector families. J Biochem 137:9-16.

    Fukuda M (2013) Rab27 effectors, pleiotropic regulators in secretory pathways. Traffic 14:949-963.

    G?kbuget D, Pereira JA, Bachofner S, Marchais A, Ciaudo C, Stoffel M, Schulte JH, Suter U (2015) The Lin28/let-7 axis is critical for myelination in the peripheral nervous system. Nat Commun 6:8584.

    Gonzalez S, Berthelot J, Jiner J, Perrin-Tricaud C, Fernando R, Chrast R, Lenaers G, Tricaud N (2016) Blocking mitochondrial calcium release in Schwann cells prevents demyelinating neuropathies. J Clin Invest 126:2773.

    Gu Y, Ji Y, Zhao Y, Liu Y, Ding F, Gu X, Yang Y (2012) The influence of substrate stiffness on the behavior and functions of Schwann cells in culture. Biomaterials 33:6672-6681.

    Heller BA, Ghidinelli M, Voelkl J, Einheber S, Smith R, Grund E, Morahan G, Chandler D, Kalaydjieva L, Giancotti F, King RH, Fejes-Toth AN, Fejes-Toth G, Feltri ML, Lang F, Salzer JL (2014) Functionally distinct PI 3-kinase pathways regulate myelination in the peripheral nervous system. J Cell Biol 204:1219-1236.

    Holt O, Kanno E, Bossi G, Booth S, Daniele T, Santoro A, Arico M, Saegusa C, Fukuda M, Griffiths GM (2008) Slp1 and Slp2-a localize to the plasma membrane of CTL and contribute to secretion from the immunological synapse. Traffic 9:446-457.

    Hou Y, Ernst SA, Stuenkel EL, Lentz SI, Williams JA (2015) Rab27A Is Present in Mouse Pancreatic Acinar Cells and Is Required for Digestive Enzyme Secretion. PLoS One 10:e0125596.

    Ishida M, Arai SP, Ohbayashi N, Fukuda M (2014) The GTPase-deficient Rab27A(Q78L) mutant inhibits melanosome transport in melanocytes through trapping of Rab27A effector protein Slac2-a/ melanophilin in their cytosol: development of a novel melanosome-targetinG tag. J Biol Chem 289:11059-11067.

    Izumi T (2007) Physiological roles of Rab27 effectors in regulated exocytosis. Endocr J 54:649-657.

    Jiang S, Shen D, Jia WJ, Han X, Shen N, Tao W, Gao X, Xue B, Li CJ (2016) GGPPS-mediated Rab27A geranylgeranylation regulates β cell dysfunction during type 2 diabetes development by affecting insulin granule docked pool formation. J Pathol 238:109-119.

    Johnson JL, Napolitano G, Monfregola J, Rocca CJ, Cherqui S, Catz SD (2013) Upregulation of the Rab27a-dependent trafficking and secretory mechanisms improves lysosomal transport, alleviates endoplasmic reticulum stress, and reduces lysosome overload in cystinosis. Mol Cell Biol 33:2950-2962.

    Johnson MI, Bunge RP, Wood PM (2001) Primary Cell Cultures for the Study of Myelination. In: Protocols for Neural Cell Culture (Fedoroff S, Richardson A, eds), pp 95: Humana Press.

    Kim JD, Willetts L, Ochkur S, Srivastava N, Hamburg R, Shayeganpour A, Seabra MC, Lee JJ, Moqbel R, Lacy P (2013) An essential role for Rab27a GTPase in eosinophil exocytosis. J Leukocyte Biol 94:1265-1274. Klein D, Martini R (2016) Myelin and macrophages in the PNS: An intimate relationship in trauma and disease. Brain Res 1641(Pt A):130-138. Kondo Y, Duncan ID (2016) Myelin repair by transplantation of myelin-forming cells in globoid cell leukodystrophy. J Neurosci Res 94:1195-1202.

    Kowluru A (2016) A lack of ‘glue’ misplaces Rab27A to cause islet dysfunction in diabetes. J Pathol 238:375-377.

    Kuroda TS, Fukuda M (2004) Rab27A-binding protein Slp2-a is required for peripheral melanosome distribution and elongated cell shape in melanocytes. Nat Cell Biol 6:1195-1203.

    Kwon HS, Johnson TV, Joe MK, Abu-Asab M, Zhang J, Chan CC, Tomarev SI (2013) Myocilin mediates myelination in the peripheral nervous system through ErbB2/3 signaling. J Biol Chem 288:26357-26371.

    Li W, Hu Y, Jiang T, Han Y, Han G, Chen J, Li X (2014) Rab27A regulates exosome secretion from lung adenocarcinoma cells A549: involvement of EPI64. APMIS 122:1080-1087.

    Liu C, Chan C (2016) An approach to enhance alignment and myelination of dorsal root ganglion neurons. J Vis Exp doi: 10.3791/54085.

    Liu N, Varma S, Shooter EM, Tolwani RJ (2005) Enhancement of Schwann cell myelin formation by K252a in the Trembler-J mouse dorsal root ganglion explant culture. J Neurosci Res 79:310-317.

    Luo S, Jaegle M, Li R, Ehring GR, Meijer D, Levinson SR (2014) The sodium channel isoform transition at developing nodes of ranvier in the peripheral nervous system: Dependence on a Genetic program and myelination-induced cluster formation. J Comp Neurol 522:4057-4073.

    Ménasché G, Ménager MM, Lefebvre JM, Deutsch E, Athman R, Lambert N, Mahlaoui N, Court M, Garin J, Fischer A, de Saint Basile G (2008) A newly identified isoform of Slp2a associates with Rab27a in cytotoxic T cells and participates to cytotoxic granule secretion. Blood 112:5052-5062.

    Ma KH, Hung HA, Svaren J (2016) Epigenomic Regulation of Schwann Cell Reprogramming in Peripheral Nerve Injury. J Neurosci 36:9135-9147.

    Marsden D, Levy H (2010) Newborn screening of lysosomal storage disorders. Clin Chem 56:1071-1079.

    Miyamoto Y, Tamano M, Torii T, Kawahara K, Nakamura K, Tanoue A, Takada S, Yamauchi J (2016) Data supporting the role of Fyn in initiating myelination in the peripheral nervous system. Data Brief 7:1098-1105.

    Montani L, Buerki-Thurnherr T, de Faria JP, Pereira JA, Dias NG, Fernandes R, Gon?alves AF, Braun A, Benninger Y, B?ttcher RT, Costell M, Nave K-A, Franklin RJM, Meijer D, Suter U, Relvas JB (2014) Profilin 1 is required for peripheral nervous system myelination. Development 141:1553-1561.

    Nave KA, Werner HB (2014) Myelination of the nervous system: mechanisms and functions. Annu Rev Cell Dev Biol 30:503-533.

    Netter P, Chan SK, Banerjee PP, Monaco-Shawver L, Noroski LM, Hanson IC, Forbes LR, Mace EM, Chinen J, Gaspar HB, Sleiman P, Hakonarson H, Klein C, Ehlayel MS, Orange JS (2016) A novel Rab27a mutation binds melanophilin, but not Munc13-4, causing immunodeficiency without albinism. J Allergy Clin Immunol 138:599-601.e3.

    Pereira JA, Lebrun-Julien F, Suter U (2012) Molecular mechanisms regulating myelination in the peripheral nervous system. Trends Neurosci 35:123-134.

    Prolo LM, Vogel H, Reimer RJ (2009) The lysosomal sialic acid transporter sialin is required for normal CNS myelination. J Neurosci 29:15355-15365.

    Rao SN, Pearse DD (2016) Regulating axonal responses to injury: the intersection between signaling pathways involved in axon myelination and the inhibition of axon regeneration. Front Mol Neurosci 9:33.

    Saegusa C, Tanaka T, Tani S, Itohara S, Mikoshiba K, Fukuda M (2006) Decreased basal mucus secretion by Slp2-a-deficient gastric surface mucous cells. Genes Cells 11:623-631.

    Salzer JL (2015) Schwann cell myelination. Cold Spring Harb Perspect Biol 7:a020529.

    Schulz A, Büttner R, Hagel C, Baader SL, Kluwe L, Salamon J, Mautner VF, Mindos T, Parkinson DB, Gehlhausen JR, Clapp DW, Morrison H (2016) The importance of nerve microenvironment for schwannoma development. Acta Neuropathol 132:289-307.

    Shen YT, Gu Y, Su WF, Zhong JF, Jin ZH, Gu XS, Chen G (2016) Rab27b is Involved in Lysosomal Exocytosis and Proteolipid Protein Trafficking in Oligodendrocytes. Neurosci Bull 32:331-340.

    Shimada-Sugawara M, Sakai E, Okamoto K, Fukuda M, Izumi T, Yoshida N, Tsukuba T (2015) Rab27A regulates transport of cell surface receptors modulating multinucleation and lysosome-related organelles in osteoclasts. Sci Rep 5:9620.

    Taveggia C (2016) Schwann cells–axon interaction in myelination. Curr Opin Neurobiol 39:24-29.

    Trajkovic K, Dhaunchak AS, Goncalves JT, Wenzel D, Schneider A, Bunt G, Nave KA, Simons M (2006) Neuron to glia signaling triggers myelin membrane exocytosis from endosomal storage sites. J Cell Biol 172:937-948.

    Wang Y, Tang X, Yu B, Gu Y, Yuan Y, Yao D, Ding F, Gu X (2012) Gene network revealed involvements of Birc2, Birc3 and Tnfrsf1a in anti-apoptosis of injured peripheral nerves. PLoS One 7:e43436.

    White R, Kr?mer-Albers E-M (2014) Axon-glia interaction and membrane traffic in myelin formation. Front Cell Neurosci 7:284.

    Yamaoka M, Ishizaki T, Kimura T (2015a) Interplay between Rab27a effectors in pancreatic β-cells. World J Diabetes 6:508-516.

    Yamaoka M, Ishizaki T, Kimura T (2015b) GTP- and GDP-dependent rab27a effectors in pancreatic beta-cells. Biol Pharm Bull 38:663-668.

    Yamaoka M, Ando T, Terabayashi T, Okamoto M, Takei M, Nishioka T, Kaibuchi K, Matsunaga K, Ishizaki R, Izumi T, Niki I, Ishizaki T, Kimura T (2016) PI3K regulates endocytosis after insulin secretion by mediating signaling crosstalk between Arf6 and Rab27a. J Cell Sci 129:637-649.

    Yasuda T, Fukuda M (2014) Slp2-a controls renal epithelial cell size through regulation of Rap-ezrin signaling independently of Rab27. J Cell Sci 127:557-570.

    Yasuda T, S. Mrozowska P, Fukuda M (2015) Functional analysis of Rab27A and its effector Slp2-a in renal epithelial cells. Methods Mol Biol 1298:127-139.

    Yuan Y, Zhang P, Yang Y, Wang X, Gu X (2004) The interaction of Schwann cells with chitosan membranes and fibers in vitro. Biomaterials 25:4273-4278.

    Zhang Z, Chen G, Zhou W, Song A, Xu T, Luo Q, Wang W, Gu XS, Duan S (2007) Regulated ATP release from astrocytes through lysosome exocytosis. Nat Cell Biol 9:945-953.

    Copyedited by Copper C, Norman C, Su WF, Yu J, Li CH, Li JY, Song LP, Zhao M

    *Correspondence to: Gang Chen, Ph.D., M.D., chengang6626@ntu.edu.cn.

    orcid: 0000-0003-3669-5687 (Gang Chen)

    10.4103/1673-5374.194755

    Accepted: 2016-10-19

    在线观看免费视频日本深夜| 欧美成狂野欧美在线观看| 九色亚洲精品在线播放| 操美女的视频在线观看| 亚洲久久久国产精品| 夜夜躁狠狠躁天天躁| 亚洲人成77777在线视频| 国产99白浆流出| 99久久国产精品久久久| 另类亚洲欧美激情| 亚洲专区字幕在线| 成人手机av| 国产精品国产高清国产av| 在线观看免费午夜福利视频| 啪啪无遮挡十八禁网站| 精品久久久久久久久久免费视频 | 黄色视频,在线免费观看| 香蕉久久夜色| 国产成人一区二区三区免费视频网站| 免费av毛片视频| 色老头精品视频在线观看| av福利片在线| av视频免费观看在线观看| 脱女人内裤的视频| 久久人妻熟女aⅴ| 超碰97精品在线观看| av天堂久久9| 久久中文字幕一级| 丰满饥渴人妻一区二区三| 久久草成人影院| 国产99白浆流出| 亚洲精品中文字幕一二三四区| 麻豆成人av在线观看| 亚洲一区高清亚洲精品| 老汉色av国产亚洲站长工具| 免费观看精品视频网站| 午夜精品久久久久久毛片777| 国产一区在线观看成人免费| 可以在线观看毛片的网站| 丝袜人妻中文字幕| 神马国产精品三级电影在线观看 | 国产高清国产精品国产三级| 18美女黄网站色大片免费观看| 午夜福利在线免费观看网站| 国产精品国产av在线观看| 黄色成人免费大全| 91精品国产国语对白视频| 亚洲在线自拍视频| 高清av免费在线| 久久久久国内视频| 涩涩av久久男人的天堂| 久久人人爽av亚洲精品天堂| 久久久久九九精品影院| 80岁老熟妇乱子伦牲交| 欧美日韩精品网址| 别揉我奶头~嗯~啊~动态视频| 在线免费观看的www视频| 国产精品免费视频内射| 黄色a级毛片大全视频| 日韩大码丰满熟妇| 自线自在国产av| 一本综合久久免费| 电影成人av| 精品国产美女av久久久久小说| 亚洲五月色婷婷综合| 丰满迷人的少妇在线观看| 操出白浆在线播放| 成人亚洲精品一区在线观看| 999久久久精品免费观看国产| 午夜成年电影在线免费观看| 日韩av在线大香蕉| 动漫黄色视频在线观看| 夫妻午夜视频| 99国产综合亚洲精品| 免费少妇av软件| 亚洲国产欧美网| 色尼玛亚洲综合影院| 欧洲精品卡2卡3卡4卡5卡区| 精品久久久久久,| 亚洲 欧美一区二区三区| 最近最新中文字幕大全免费视频| av在线播放免费不卡| 搡老熟女国产l中国老女人| 在线av久久热| 母亲3免费完整高清在线观看| 午夜a级毛片| 亚洲成av片中文字幕在线观看| 岛国在线观看网站| 成人三级做爰电影| 免费搜索国产男女视频| 国产精品香港三级国产av潘金莲| 两性午夜刺激爽爽歪歪视频在线观看 | 欧美人与性动交α欧美精品济南到| 国产精品香港三级国产av潘金莲| 日韩国内少妇激情av| 国产精品秋霞免费鲁丝片| 99国产精品一区二区蜜桃av| 亚洲,欧美精品.| 高清欧美精品videossex| 国产激情久久老熟女| 91国产中文字幕| 久久中文看片网| 韩国精品一区二区三区| 色播在线永久视频| 亚洲第一欧美日韩一区二区三区| 中文字幕另类日韩欧美亚洲嫩草| 免费在线观看完整版高清| 国产亚洲av高清不卡| 亚洲欧洲精品一区二区精品久久久| 久久精品人人爽人人爽视色| 一级a爱片免费观看的视频| 精品一区二区三区av网在线观看| 视频区图区小说| 国产av精品麻豆| 亚洲成人精品中文字幕电影 | 丁香欧美五月| 又黄又爽又免费观看的视频| 精品第一国产精品| 很黄的视频免费| 如日韩欧美国产精品一区二区三区| 在线天堂中文资源库| 激情在线观看视频在线高清| 在线观看免费日韩欧美大片| 99国产精品一区二区蜜桃av| 成年人免费黄色播放视频| 亚洲av成人av| 中文字幕人妻丝袜一区二区| 国产免费av片在线观看野外av| 国产免费av片在线观看野外av| 天天影视国产精品| 日韩欧美一区视频在线观看| a级片在线免费高清观看视频| 在线观看免费视频网站a站| 欧美激情 高清一区二区三区| 亚洲av美国av| 国产精品免费一区二区三区在线| 天堂动漫精品| 国产三级黄色录像| 欧美日韩乱码在线| 啦啦啦 在线观看视频| 色综合站精品国产| 日韩欧美免费精品| 又大又爽又粗| 波多野结衣一区麻豆| 国产成人av教育| 国产亚洲欧美精品永久| 黑人猛操日本美女一级片| 50天的宝宝边吃奶边哭怎么回事| xxx96com| av电影中文网址| 夜夜看夜夜爽夜夜摸 | 国产免费av片在线观看野外av| 美女高潮喷水抽搐中文字幕| 亚洲第一av免费看| 国产成+人综合+亚洲专区| 亚洲自偷自拍图片 自拍| 久久香蕉精品热| 一本综合久久免费| 69精品国产乱码久久久| 黄色丝袜av网址大全| 18禁黄网站禁片午夜丰满| 国产av又大| 国产成人影院久久av| 91国产中文字幕| 日本wwww免费看| 日韩有码中文字幕| 欧美色视频一区免费| 又大又爽又粗| 成人手机av| 久久久久久大精品| 日本精品一区二区三区蜜桃| 琪琪午夜伦伦电影理论片6080| 亚洲av电影在线进入| 中亚洲国语对白在线视频| 男人的好看免费观看在线视频 | 琪琪午夜伦伦电影理论片6080| 一区福利在线观看| 亚洲激情在线av| 1024香蕉在线观看| 亚洲视频免费观看视频| 99热只有精品国产| 在线免费观看的www视频| 国产午夜精品久久久久久| av在线天堂中文字幕 | 十分钟在线观看高清视频www| 99香蕉大伊视频| 国产国语露脸激情在线看| 精品熟女少妇八av免费久了| 午夜精品久久久久久毛片777| 久久这里只有精品19| 桃色一区二区三区在线观看| 欧美黄色淫秽网站| www.熟女人妻精品国产| 中文字幕av电影在线播放| 亚洲自偷自拍图片 自拍| 精品久久久精品久久久| 亚洲av五月六月丁香网| 一边摸一边做爽爽视频免费| 九色亚洲精品在线播放| 亚洲欧美日韩另类电影网站| 激情视频va一区二区三区| 身体一侧抽搐| 成人av一区二区三区在线看| 亚洲av成人不卡在线观看播放网| 少妇粗大呻吟视频| 最好的美女福利视频网| 一级a爱片免费观看的视频| 丰满的人妻完整版| 老熟妇仑乱视频hdxx| 女人高潮潮喷娇喘18禁视频| 他把我摸到了高潮在线观看| 99精品欧美一区二区三区四区| 长腿黑丝高跟| 久久久久久久精品吃奶| 青草久久国产| 男人操女人黄网站| 久久这里只有精品19| 欧美中文综合在线视频| 人人澡人人妻人| 搡老熟女国产l中国老女人| 黑人巨大精品欧美一区二区mp4| 欧美日韩亚洲高清精品| 日本五十路高清| 欧美日韩亚洲高清精品| 韩国精品一区二区三区| 欧美日本亚洲视频在线播放| 欧美黑人精品巨大| av有码第一页| 久久精品国产亚洲av高清一级| 国产成人精品无人区| 高清毛片免费观看视频网站 | 91麻豆av在线| 国产亚洲欧美98| 法律面前人人平等表现在哪些方面| 高潮久久久久久久久久久不卡| 国产成+人综合+亚洲专区| 黄色 视频免费看| 美女大奶头视频| 日韩欧美三级三区| 国产av精品麻豆| 91国产中文字幕| 日韩欧美在线二视频| 亚洲 欧美一区二区三区| 欧美不卡视频在线免费观看 | 老熟妇仑乱视频hdxx| av视频免费观看在线观看| 一二三四社区在线视频社区8| 日本a在线网址| 欧美日韩福利视频一区二区| 精品午夜福利视频在线观看一区| 看免费av毛片| 欧美性长视频在线观看| 免费在线观看影片大全网站| 久久久国产欧美日韩av| 久久亚洲精品不卡| 日韩人妻精品一区2区三区| 大码成人一级视频| 伦理电影免费视频| 国产成人精品久久二区二区免费| 亚洲五月色婷婷综合| 欧美日韩亚洲高清精品| av视频免费观看在线观看| 国产av精品麻豆| 波多野结衣一区麻豆| 久久久久精品国产欧美久久久| 99久久99久久久精品蜜桃| 亚洲色图av天堂| 久久久久亚洲av毛片大全| 免费高清视频大片| 视频在线观看一区二区三区| 十分钟在线观看高清视频www| 色综合婷婷激情| 精品欧美一区二区三区在线| 精品国内亚洲2022精品成人| 久久香蕉精品热| 啦啦啦免费观看视频1| 琪琪午夜伦伦电影理论片6080| 日韩人妻精品一区2区三区| 色尼玛亚洲综合影院| 一级毛片精品| 亚洲成人免费电影在线观看| 国产精品久久久人人做人人爽| 亚洲av熟女| 国产激情久久老熟女| 搡老熟女国产l中国老女人| 久久久国产欧美日韩av| 日韩视频一区二区在线观看| 十八禁人妻一区二区| 女人被狂操c到高潮| 脱女人内裤的视频| 成人特级黄色片久久久久久久| 丰满的人妻完整版| 这个男人来自地球电影免费观看| 在线av久久热| 不卡av一区二区三区| 久久人人精品亚洲av| 99精国产麻豆久久婷婷| 欧美黄色淫秽网站| 无限看片的www在线观看| 婷婷精品国产亚洲av在线| 国产精品av久久久久免费| 99热国产这里只有精品6| 91老司机精品| 麻豆久久精品国产亚洲av | 欧美丝袜亚洲另类 | 亚洲一区二区三区色噜噜 | 亚洲国产欧美一区二区综合| 免费不卡黄色视频| 国产熟女xx| 天天躁狠狠躁夜夜躁狠狠躁| 免费高清在线观看日韩| a在线观看视频网站| 欧洲精品卡2卡3卡4卡5卡区| 两性午夜刺激爽爽歪歪视频在线观看 | 国产精品永久免费网站| 老司机深夜福利视频在线观看| 韩国精品一区二区三区| 国产成人精品在线电影| 99热国产这里只有精品6| 丝袜美足系列| 亚洲精品一区av在线观看| 久久人妻福利社区极品人妻图片| 少妇的丰满在线观看| 757午夜福利合集在线观看| 男人舔女人下体高潮全视频| 久久精品成人免费网站| 91大片在线观看| 亚洲 欧美 日韩 在线 免费| 在线免费观看的www视频| 久久香蕉激情| 精品高清国产在线一区| 亚洲少妇的诱惑av| 性色av乱码一区二区三区2| 中出人妻视频一区二区| 亚洲av五月六月丁香网| 久久精品国产清高在天天线| 亚洲国产欧美一区二区综合| 人人澡人人妻人| 91成人精品电影| 亚洲aⅴ乱码一区二区在线播放 | 黄色怎么调成土黄色| 纯流量卡能插随身wifi吗| 琪琪午夜伦伦电影理论片6080| 午夜老司机福利片| 无限看片的www在线观看| 国产成人系列免费观看| 免费人成视频x8x8入口观看| 在线播放国产精品三级| 身体一侧抽搐| 国产一区二区三区在线臀色熟女 | 男女午夜视频在线观看| 最近最新免费中文字幕在线| 久久人人爽av亚洲精品天堂| 老熟妇仑乱视频hdxx| 国产精品av久久久久免费| 成人18禁在线播放| 亚洲中文字幕日韩| 女性生殖器流出的白浆| 久久久精品国产亚洲av高清涩受| 女性被躁到高潮视频| 国产精品久久久人人做人人爽| 欧美精品一区二区免费开放| 午夜日韩欧美国产| 国产一区在线观看成人免费| 亚洲色图 男人天堂 中文字幕| 亚洲国产欧美网| 亚洲国产精品999在线| 亚洲五月婷婷丁香| 热re99久久国产66热| 99re在线观看精品视频| 一级,二级,三级黄色视频| 成人18禁高潮啪啪吃奶动态图| 悠悠久久av| 亚洲aⅴ乱码一区二区在线播放 | 9色porny在线观看| 亚洲欧美精品综合一区二区三区| 久久香蕉国产精品| www国产在线视频色| 午夜两性在线视频| 嫩草影院精品99| 成熟少妇高潮喷水视频| 999久久久国产精品视频| 欧美激情高清一区二区三区| 黑人猛操日本美女一级片| 精品国产超薄肉色丝袜足j| 俄罗斯特黄特色一大片| 午夜成年电影在线免费观看| 亚洲精品中文字幕在线视频| 国产av精品麻豆| 久久影院123| 欧美日本亚洲视频在线播放| 最近最新免费中文字幕在线| 久久久久精品国产欧美久久久| 最近最新中文字幕大全免费视频| 日韩欧美在线二视频| 久久久久久免费高清国产稀缺| 国产亚洲欧美在线一区二区| 欧美丝袜亚洲另类 | 99国产极品粉嫩在线观看| 大型av网站在线播放| 在线播放国产精品三级| 免费在线观看影片大全网站| 国产精品自产拍在线观看55亚洲| 久久久久精品国产欧美久久久| 天天躁夜夜躁狠狠躁躁| 欧美在线一区亚洲| 窝窝影院91人妻| 搡老岳熟女国产| 波多野结衣一区麻豆| 亚洲va日本ⅴa欧美va伊人久久| 久久狼人影院| 欧美精品一区二区免费开放| 真人做人爱边吃奶动态| 天天躁狠狠躁夜夜躁狠狠躁| 欧美精品一区二区免费开放| 国产伦一二天堂av在线观看| 在线永久观看黄色视频| 亚洲一卡2卡3卡4卡5卡精品中文| 色婷婷久久久亚洲欧美| 久久精品影院6| 老司机午夜十八禁免费视频| 在线观看免费视频日本深夜| 大陆偷拍与自拍| 国产精品一区二区在线不卡| 久久欧美精品欧美久久欧美| 亚洲五月天丁香| 一级毛片女人18水好多| 亚洲第一av免费看| 制服诱惑二区| 成人永久免费在线观看视频| 精品乱码久久久久久99久播| 成人国语在线视频| 身体一侧抽搐| 久久99一区二区三区| xxxhd国产人妻xxx| 色在线成人网| 欧美精品一区二区免费开放| 99国产精品一区二区三区| 在线天堂中文资源库| 欧美丝袜亚洲另类 | 涩涩av久久男人的天堂| 精品国产乱码久久久久久男人| 国产亚洲欧美在线一区二区| 亚洲成人国产一区在线观看| 色婷婷av一区二区三区视频| 麻豆成人av在线观看| 亚洲人成77777在线视频| 人人澡人人妻人| 男人舔女人下体高潮全视频| 精品久久久久久电影网| 亚洲 欧美 日韩 在线 免费| 亚洲aⅴ乱码一区二区在线播放 | 女性被躁到高潮视频| 欧美激情 高清一区二区三区| 成年女人毛片免费观看观看9| 91字幕亚洲| 国产精品偷伦视频观看了| 亚洲一区中文字幕在线| 黄频高清免费视频| 精品高清国产在线一区| 国产精品免费一区二区三区在线| 亚洲一区高清亚洲精品| 妹子高潮喷水视频| 久久精品91无色码中文字幕| 午夜91福利影院| 美女高潮到喷水免费观看| 国产日韩一区二区三区精品不卡| 国产主播在线观看一区二区| 久久久国产成人精品二区 | 欧美日韩福利视频一区二区| 97人妻天天添夜夜摸| 99国产综合亚洲精品| 午夜日韩欧美国产| 黄色视频不卡| 久久人妻av系列| 国产蜜桃级精品一区二区三区| 亚洲人成电影免费在线| 激情视频va一区二区三区| 久久人妻熟女aⅴ| 日日爽夜夜爽网站| 日韩欧美三级三区| 最新在线观看一区二区三区| 亚洲精品在线观看二区| 黄色片一级片一级黄色片| 国产精品98久久久久久宅男小说| 叶爱在线成人免费视频播放| 在线国产一区二区在线| 久久久水蜜桃国产精品网| 成人影院久久| 在线观看免费视频网站a站| 人人妻人人澡人人看| 天天躁夜夜躁狠狠躁躁| 国产极品粉嫩免费观看在线| 欧美激情久久久久久爽电影 | 黑人操中国人逼视频| 国产免费av片在线观看野外av| svipshipincom国产片| 国产精品久久久av美女十八| 国产成人av教育| 国产欧美日韩一区二区三区在线| 桃红色精品国产亚洲av| 在线观看66精品国产| 啪啪无遮挡十八禁网站| 热99国产精品久久久久久7| 精品久久久久久久毛片微露脸| 国产精品电影一区二区三区| 久久中文看片网| 级片在线观看| 一进一出好大好爽视频| www.熟女人妻精品国产| 久久精品aⅴ一区二区三区四区| 婷婷丁香在线五月| 午夜福利欧美成人| 精品午夜福利视频在线观看一区| 成人亚洲精品一区在线观看| av网站在线播放免费| 亚洲欧美日韩无卡精品| 少妇的丰满在线观看| 国产野战对白在线观看| 亚洲免费av在线视频| 97碰自拍视频| 69精品国产乱码久久久| 国产一区二区三区视频了| 丝袜人妻中文字幕| av免费在线观看网站| 国产成人精品久久二区二区91| 香蕉久久夜色| 久久中文字幕一级| 久久精品亚洲精品国产色婷小说| 国产三级黄色录像| 中文字幕高清在线视频| 国产三级黄色录像| 热re99久久国产66热| 一个人免费在线观看的高清视频| 看免费av毛片| 成年人免费黄色播放视频| 国产1区2区3区精品| 国产精品爽爽va在线观看网站 | 午夜福利欧美成人| 色综合欧美亚洲国产小说| 国产野战对白在线观看| 国产成人欧美在线观看| 久久人人精品亚洲av| 两人在一起打扑克的视频| 老熟妇仑乱视频hdxx| 视频区图区小说| 乱人伦中国视频| 性少妇av在线| 男女午夜视频在线观看| 久久久国产成人精品二区 | aaaaa片日本免费| 亚洲少妇的诱惑av| 两人在一起打扑克的视频| 天天躁狠狠躁夜夜躁狠狠躁| 91麻豆av在线| 一级a爱片免费观看的视频| 成年女人毛片免费观看观看9| 啦啦啦免费观看视频1| 人妻久久中文字幕网| 在线观看免费视频网站a站| 成人18禁在线播放| 欧美黄色片欧美黄色片| 人人妻人人添人人爽欧美一区卜| 19禁男女啪啪无遮挡网站| 男男h啪啪无遮挡| 久久人妻福利社区极品人妻图片| 亚洲国产欧美网| 天堂中文最新版在线下载| 欧美激情久久久久久爽电影 | 1024视频免费在线观看| 九色亚洲精品在线播放| 高清毛片免费观看视频网站 | 中文字幕人妻丝袜一区二区| 脱女人内裤的视频| 国产亚洲欧美在线一区二区| 国产1区2区3区精品| 久久久精品欧美日韩精品| 亚洲自偷自拍图片 自拍| 日日干狠狠操夜夜爽| 亚洲专区国产一区二区| 欧美精品一区二区免费开放| 老司机靠b影院| 久久这里只有精品19| 最好的美女福利视频网| 久久久国产一区二区| 久久亚洲精品不卡| 中文字幕最新亚洲高清| 长腿黑丝高跟| 午夜免费鲁丝| 视频区欧美日本亚洲| 亚洲专区字幕在线| 电影成人av| 免费在线观看影片大全网站| x7x7x7水蜜桃| 成人三级黄色视频| 中出人妻视频一区二区| 欧美黑人精品巨大| 欧美大码av| 琪琪午夜伦伦电影理论片6080| 美国免费a级毛片| 久久久久久久久久久久大奶| 在线观看舔阴道视频| 69av精品久久久久久| 黄网站色视频无遮挡免费观看| 别揉我奶头~嗯~啊~动态视频| 国产三级在线视频| 夫妻午夜视频| 欧美日本中文国产一区发布| 好看av亚洲va欧美ⅴa在| av网站免费在线观看视频| 不卡一级毛片| 久久久精品国产亚洲av高清涩受| 精品国产一区二区三区四区第35| 国产亚洲欧美精品永久| 亚洲,欧美精品.|