The molecular mechanisms by which dense core vesicles(DCVs) translocate,tether,dock and prime are poorly understood.In this study,Caenorhabditis elegans was used as a model organism to study the function of Rab protei...The molecular mechanisms by which dense core vesicles(DCVs) translocate,tether,dock and prime are poorly understood.In this study,Caenorhabditis elegans was used as a model organism to study the function of Rab proteins and their effectors in DCV exocytosis.RAB-27/AEX-6,but not RAB-3,was found to be required for peptide release from neurons.By analyzing the movement of DCVs approaching the plasma membrane using total internal reflection fluorescence microscopy,we demonstrated that RAB-27/AEX-6 is involved in the tethering of DCVs and that its effector rabphilin/RBF-1 is required for the initial tethering and subsequent stabilization by docking.展开更多
AIM:To investigate the association of Rab27A and Rab27B expression with clinicopathological characteristics and prognosis of hepatocellular carcinoma(HCC).METHODS:We used reverse transcription polymerase chain reactio...AIM:To investigate the association of Rab27A and Rab27B expression with clinicopathological characteristics and prognosis of hepatocellular carcinoma(HCC).METHODS:We used reverse transcription polymerase chain reaction(RT-PCR),real-time PCR,and Western blotting to detect Rab27A and Rab27B mRNA and protein expression in 5 human HCC lines and the immortalized hepatic HL-7702 cell line.We further examined 148 primary HCC samples matched with adjacent normal tissue and 80 non-HCC specimens by immunohistochemistry to evaluate the correlation of Rab27A and Rab27B expression with clinicopathological features and prognosis.RESULTS:Our data showed that Rab27A and Rab27Bwere differentially expressed in cell lines and primary HCC tumors.Rab27A mRNA and protein were detected in 67%(4/6)of human cell lines and 80%(4/5)of HCC cell lines,while Rab27B was found in 50%(3/6)of human lines and 40%(2/5)of HCC lines.Rab27A expression was higher in primary HCC(46.2%,66/143)than in matched adjacent tissue(24.3%,33/136,P<0.001),whereas immunopositivity for Rab27B was lower in primary HCC(57.4%,81/141)than in matched adjacent tissue(87.5%,119/136,P<0.001).Analysis of clinicopathological characteristics of 148 HCC specimens revealed significant correlations between Rab27A and Rab27B expression and tumor tumor-node-metastasis(TNM)classification(P=0.046 and P=0.027,respectively),and between strong Rab27A expression and tumor differentiation grade(P=0.008).Survival analyses revealed that patients with Rab27A+or Rab27B+tumors had significantly reduced overall survival compared with that of patients with Rab27A-or Rab27B-tumors(P= 0.015 and P=0.005,respectively).Risk analyses revealed that Rab27B+and TNMⅢ-Ⅳwere independent poor prognosis factors associated with a 3.36-and 3.37fold higher relative risk of death,respectively.CONCLUSION:Rab27A and Rab27B expression were closely correlated with tumor progression and can be valuable prognostic indicators for HCC patients.展开更多
Background: Acute lung injury(ALI) is a major component of multiple organ dysfunction syndrome(MODS) following pulmonary and systemic infection. Alveolar macrophages(AMφ) are at the center of ALI pathogenesis. Emergi...Background: Acute lung injury(ALI) is a major component of multiple organ dysfunction syndrome(MODS) following pulmonary and systemic infection. Alveolar macrophages(AMφ) are at the center of ALI pathogenesis. Emerging evidence has shown that cell-cell interactions in the lungs play an important regulatory role in the development of acute lung inflammation. However, the underneath mechanisms remain poorly addressed. In this study, we explore a novel function of lung epithelial cells(LEPCs) in regulating the release of exosomes from AMφ following LPS stimulation.Methods: For the in vivo experiments, C57 BL/6 wildtype(WT) mice were treated with lipopolysaccharide(LPS)(2 mg/kg) in 0.2 ml of saline via intratracheal aerosol administration. Bronchoalveolar lavage fluid was collected at 0–24 h after LPS treatment, and exosomes derived from AMφ were measured. For the in vitro studies, LEPCs and bone marrowderived Mφ(BMDM) were isolated from WT or TLR4-/-mice and were then cocultured in the Transwell? system. After coculture for 0–24 h, the BMDM and supernatant were harvested for the measurement of exosomes and cytokines.Results: We demonstrate that LPS induces macrophages(Mφ) to release exosomes, which are then internalized by neighboring Mφ to promote TNF-α expression. The secreted interleukin(IL)-25 from LEPCs downregulates Rab27 a and Rab27 b expression in Mφ, resulting in suppressed exosome release and thereby attenuating exosome-induced TNF-α expression and secretion.Conclusion: These findings reveal a previously unidentified crosstalk pathway between LEPCs and Mφ that negatively regulates the inflammatory responses of Mφ to LPS. Modulating IL-25 signaling and targeting exosome release may present a new therapeutic strategy for the treatment of ALI.展开更多
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 e...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 myelination in vitro.展开更多
AIM: To develop novel biomarkers of rectal radiotherapy, we measured gene expression profiles on biopsies taken before and during preoperative radiotherapy. METHODS: Six patients presenting with a locally advanced rec...AIM: To develop novel biomarkers of rectal radiotherapy, we measured gene expression profiles on biopsies taken before and during preoperative radiotherapy. METHODS: Six patients presenting with a locally advanced rectal cancer (T>T2, N0/Nx, M0) eligible for preoperative radiotherapy (45 Gy in 25 fractions) were selected in a pilot study. Six tumor and 3 normal tissues biopsies were taken before and during radiotherapy,after a dose of 7.2 Gy at a median time of 1 h following irradiation (0:27-2:12). Tumor or normal tissue purity was assessed by a pathologist prior to RNA extraction. Mean RNA content was 23 μg/biopsy (14-37) before radiotherapy and 22.7 μg/biopsy (12-35) during radiotherapy. After RNA amplification, biopsies were analysed with 54K HG-U133A Plus 2.0 Affymetrix expression micro-arrays. Data were normalized according to MAS5 algorithm. A gene expression ratio was calculated as: (gene expression during radiotherapy-gene expression before radiotherapy)/gene expression before radiotherapy. Were selected genes that showed a ratio higher than ± 0.5 in all 6 patients. RESULTS: Microarray analysis showed that preoperative radiotherapy significantly up-regulated 31 genes and down-regulated 6 genes. According to the Gene Ontology project classification, these genes are involved in protein metabolism (ADAMDEC1 ; AKAP7 ; CAPN5 ; CLIC5 ; CPE ; CREB3L1 ; NEDD4L ; RAB27A), ion transport (AKAP7 ; ATP2A3 ; CCL28 ; CLIC5 ; F2RL2 ; NEDD4L ; SLC6A8), transcription (AKAP7 ; CREB3L1 ; ISX ; PAB-PC1L ; TXNIP), signal transduction (CAPN5 ; F2RL2 ; RA- B27A ; TNFRSF11A), cell adhesion (ADAMDEC1 ; PXDN ; SPON1 ; S100A2), immune response (CCL28 ; PXDN ; TNFRSF11A) and apoptosis (ITM2C ; PDCD4 ; PVT1). Up-regulation of 3 genes (CCL28 ; CLIC5 ; PDCD4) was detected by 2 different probes and up-regulation of 2 genes (RAB27A ; TXNIP) by 3 probes. CONCLUSION: Micro-arrays can efficiently assess early transcriptomic changes during preoperative radiotherapy for rectal cancer, and may help better understand tumor radioresistance.展开更多
基金supported by the National Basic Research Program of China(Grant No. 2010CB833701)the National Natural Science Foundation of China(Grant Nos. 30870564 and 90913022)the CAS Project(Grant No.KSCX2-SW-224)
文摘The molecular mechanisms by which dense core vesicles(DCVs) translocate,tether,dock and prime are poorly understood.In this study,Caenorhabditis elegans was used as a model organism to study the function of Rab proteins and their effectors in DCV exocytosis.RAB-27/AEX-6,but not RAB-3,was found to be required for peptide release from neurons.By analyzing the movement of DCVs approaching the plasma membrane using total internal reflection fluorescence microscopy,we demonstrated that RAB-27/AEX-6 is involved in the tethering of DCVs and that its effector rabphilin/RBF-1 is required for the initial tethering and subsequent stabilization by docking.
文摘AIM:To investigate the association of Rab27A and Rab27B expression with clinicopathological characteristics and prognosis of hepatocellular carcinoma(HCC).METHODS:We used reverse transcription polymerase chain reaction(RT-PCR),real-time PCR,and Western blotting to detect Rab27A and Rab27B mRNA and protein expression in 5 human HCC lines and the immortalized hepatic HL-7702 cell line.We further examined 148 primary HCC samples matched with adjacent normal tissue and 80 non-HCC specimens by immunohistochemistry to evaluate the correlation of Rab27A and Rab27B expression with clinicopathological features and prognosis.RESULTS:Our data showed that Rab27A and Rab27Bwere differentially expressed in cell lines and primary HCC tumors.Rab27A mRNA and protein were detected in 67%(4/6)of human cell lines and 80%(4/5)of HCC cell lines,while Rab27B was found in 50%(3/6)of human lines and 40%(2/5)of HCC lines.Rab27A expression was higher in primary HCC(46.2%,66/143)than in matched adjacent tissue(24.3%,33/136,P<0.001),whereas immunopositivity for Rab27B was lower in primary HCC(57.4%,81/141)than in matched adjacent tissue(87.5%,119/136,P<0.001).Analysis of clinicopathological characteristics of 148 HCC specimens revealed significant correlations between Rab27A and Rab27B expression and tumor tumor-node-metastasis(TNM)classification(P=0.046 and P=0.027,respectively),and between strong Rab27A expression and tumor differentiation grade(P=0.008).Survival analyses revealed that patients with Rab27A+or Rab27B+tumors had significantly reduced overall survival compared with that of patients with Rab27A-or Rab27B-tumors(P= 0.015 and P=0.005,respectively).Risk analyses revealed that Rab27B+and TNMⅢ-Ⅳwere independent poor prognosis factors associated with a 3.36-and 3.37fold higher relative risk of death,respectively.CONCLUSION:Rab27A and Rab27B expression were closely correlated with tumor progression and can be valuable prognostic indicators for HCC patients.
基金supported by the National Institute of Health Grant(R01-HL-079669 by JF and MAW)the National Institute of Health Grant(R56-HL-123882 by JF)+3 种基金the National Institute of Health Grant(R01HL076179–09 by PW and JF)the VA Merit Award(1I01BX002729 by JF)the National Natural Science Foundation of China(81470262 by JF)the National Institute of Health Grant(R01GM102146 by MJS)
文摘Background: Acute lung injury(ALI) is a major component of multiple organ dysfunction syndrome(MODS) following pulmonary and systemic infection. Alveolar macrophages(AMφ) are at the center of ALI pathogenesis. Emerging evidence has shown that cell-cell interactions in the lungs play an important regulatory role in the development of acute lung inflammation. However, the underneath mechanisms remain poorly addressed. In this study, we explore a novel function of lung epithelial cells(LEPCs) in regulating the release of exosomes from AMφ following LPS stimulation.Methods: For the in vivo experiments, C57 BL/6 wildtype(WT) mice were treated with lipopolysaccharide(LPS)(2 mg/kg) in 0.2 ml of saline via intratracheal aerosol administration. Bronchoalveolar lavage fluid was collected at 0–24 h after LPS treatment, and exosomes derived from AMφ were measured. For the in vitro studies, LEPCs and bone marrowderived Mφ(BMDM) were isolated from WT or TLR4-/-mice and were then cocultured in the Transwell? system. After coculture for 0–24 h, the BMDM and supernatant were harvested for the measurement of exosomes and cytokines.Results: We demonstrate that LPS induces macrophages(Mφ) to release exosomes, which are then internalized by neighboring Mφ to promote TNF-α expression. The secreted interleukin(IL)-25 from LEPCs downregulates Rab27 a and Rab27 b expression in Mφ, resulting in suppressed exosome release and thereby attenuating exosome-induced TNF-α expression and secretion.Conclusion: These findings reveal a previously unidentified crosstalk pathway between LEPCs and Mφ that negatively regulates the inflammatory responses of Mφ to LPS. Modulating IL-25 signaling and targeting exosome release may present a new therapeutic strategy for the treatment of ALI.
基金supported by the National Natural Science Foundation of China,No.31071251,81471255,and 81471259a grant from the Ministry of Science and Technology of China(973 Program),No.2014CB542202+2 种基金a grant from the Basic Research Program of Education Department of Jiangsu Province,China,No.14KJA310004a grant from the Natural Science Research Project of Nantong Science and Technology Bureau,China,No.HS2013014a grant from the Natural Science Research Project of Nantong University,China,No.13Z008
文摘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 myelination in vitro.
基金Supported by Ligue Contre le Cancer, Programme Hospitalier de Recherche Clinique (20-R6)
文摘AIM: To develop novel biomarkers of rectal radiotherapy, we measured gene expression profiles on biopsies taken before and during preoperative radiotherapy. METHODS: Six patients presenting with a locally advanced rectal cancer (T>T2, N0/Nx, M0) eligible for preoperative radiotherapy (45 Gy in 25 fractions) were selected in a pilot study. Six tumor and 3 normal tissues biopsies were taken before and during radiotherapy,after a dose of 7.2 Gy at a median time of 1 h following irradiation (0:27-2:12). Tumor or normal tissue purity was assessed by a pathologist prior to RNA extraction. Mean RNA content was 23 μg/biopsy (14-37) before radiotherapy and 22.7 μg/biopsy (12-35) during radiotherapy. After RNA amplification, biopsies were analysed with 54K HG-U133A Plus 2.0 Affymetrix expression micro-arrays. Data were normalized according to MAS5 algorithm. A gene expression ratio was calculated as: (gene expression during radiotherapy-gene expression before radiotherapy)/gene expression before radiotherapy. Were selected genes that showed a ratio higher than ± 0.5 in all 6 patients. RESULTS: Microarray analysis showed that preoperative radiotherapy significantly up-regulated 31 genes and down-regulated 6 genes. According to the Gene Ontology project classification, these genes are involved in protein metabolism (ADAMDEC1 ; AKAP7 ; CAPN5 ; CLIC5 ; CPE ; CREB3L1 ; NEDD4L ; RAB27A), ion transport (AKAP7 ; ATP2A3 ; CCL28 ; CLIC5 ; F2RL2 ; NEDD4L ; SLC6A8), transcription (AKAP7 ; CREB3L1 ; ISX ; PAB-PC1L ; TXNIP), signal transduction (CAPN5 ; F2RL2 ; RA- B27A ; TNFRSF11A), cell adhesion (ADAMDEC1 ; PXDN ; SPON1 ; S100A2), immune response (CCL28 ; PXDN ; TNFRSF11A) and apoptosis (ITM2C ; PDCD4 ; PVT1). Up-regulation of 3 genes (CCL28 ; CLIC5 ; PDCD4) was detected by 2 different probes and up-regulation of 2 genes (RAB27A ; TXNIP) by 3 probes. CONCLUSION: Micro-arrays can efficiently assess early transcriptomic changes during preoperative radiotherapy for rectal cancer, and may help better understand tumor radioresistance.
