[Single non-blood-related umbilical cord blood transplantation using a reduced-intensity conditioning regimen for the treatment of severe aplastic anemia]

Objective: To evaluated the clinical efficacy of a reduced-intensity preconditioning regimen for single non-blood-related umbilical cord blood transplantation (sUCBT) in the treatment of severe aplastic anemia (SAA) . Methods: The clinical data of 63 patients with SAA who underwent sUCBT from January 2021 to July 2023 at the Department of Hematology of the First Affiliated Hospital of USTC were retrospectively analyzed. Fifty-two patients received total body irradiation/total bone marrow irradiation (TMI) combined with fludarabine or a cyclophosphamide- conditioning regimen (non-rATG group) , while 11 patients received rabbit anti-human thymocyte immunoglobulin (rATG) combined with TMI, fludarabine, or the cyclophosphamide-conditioning regimen (rATG group) . All patients received cyclosporine A and mycophenolate mofetil for graft-versus-host disease (GVHD) prophylaxis. Complications post-transplantation and long-term survival were compared between the two groups. Results: The baseline parameters were balanced between the two groups (P>0.05) . In the rATG group, all patients achieved stem cell engraftment, and in the non-rATG group, five patients had primary graft failure. There was no significant difference in the cumulative incidence of neutrophil engraftment at 42 days after transplantation or platelet engraftment at 60 days between the two groups. The incidence of grade Ⅱ-Ⅳ acute GVHD in the rATG group was significantly lower than in the non-rATG group (10.0% vs. 46.2% , P=0.032) , and the differences in the cumulative incidences of grade Ⅲ/Ⅳ acute GVHD and 1-year chronic GVHD were not statistically significant (P=0.367 and P=0.053, respectively) . There were no significant differences in the incidences of pre-engraftment syndrome, bacterial bloodstream infections, cytomegalovirus viremia, or hemorrhagic cystitis between the two groups (P>0.05 for all) . The median follow-up time for surviving patients was 536 (61-993) days, and the 1-year transplantation related mortality (TRM) of all patients after transplantation was 13.0% (95% CI 6.7% -24.3% ) . Among the patients in the non-rATG and rATG groups, 15.5% (95% CI 8.1% -28.6% ) and 0% (P=0.189) , respectively, had mutations. The 1-year overall survival (OS) rate of all patients after transplantation was 87.0% (95% CI 75.7% -93.3% ) . The 1-year OS rates in the rATG group and non-rATG group after transplantation were 100% and 84.5% , respectively (95% CI 71.4% -91.9% ) (P=0.198) . Conclusion: The preliminary results of sUCBT with a low-dose irradiation-based reduced-intensity conditioning regimen with fludarabine/cyclophosphamide for the treatment of patients with SAA showed good efficacy. Early application of low-dose rATG can reduce the incidence of acute GVHD after transplantation without increasing the risk of implantation failure or infection.

[Efficacy and safety of ruxolitinib in the salvage treatment of chronic graft versus-host disease]

Objective: To investigate the efficacy and safety of low-dose Ruxolitinib in the treatment of patients with chronic graft-versus-host disease (cGVHD) and refractory to the first-line and/or second-line drugs after allogeneic hematopoietic stem cell transplantation. Methods: The clinical data was retrospectively analyzed of patients diagnosed with cGVHD in Anhui Provincial Hospital from July 9, 2018 to May 23, 2019. They were refractory to first-line and second-line drugs and were given a low-dose of Ruxolitinib (a dose of 5 mg twice daily if body weight ≥ 25 kg and 2.5 mg twice daily if body weight<25 kg). There was 2.5 mg reduction per week or every two weeks if the condition improved until withdrawal. The efficacy and safety of Ruxolitinib were retrospectively analyzed weekly or biweekly. If the condition improved, the dosage would be reduced by 2.5 mg weekly or biweekly until discontinuance. Results: A total of 47 patients were included in the study,and the median time of taking Ruxolitinib was 55 (21-154) days. The median time of taking effect was 14(7-28) days. The overall response rate was 87.2% (41/47). The complete response rate was 63.8% (30/47) and the partial response rate was 23.4%(11/47). Among them, 13 cases were mild and the overall response rate was 100%(13/13). Twenty one cases were moderate and the overall response rate was 90.5%(19/21). Thirteen cases were severe and the overall response rate was 69.2%(9/13). The highest overall response rate of all organs the was 100% in the gastrointestinal tract (7/7), and it was 95.8%(23/24) for the skin, 83.3%(5/6) for the liver and 76.9%(10/13) for the lung. The highest rate of complete organ response was 95.8% for skin. Eight patients (17%) developed cytopenia, of which 2(4.2%) were with a decrease of 3-4 degree hemoglobin. Recrudescence of cytomegalovirus occurred in 3 patients (6.4%). After withdrawal of Ruxolitinib, 6 patients (12.7%) had recurrence of cGVHD. The median time to relapse was 35.5(7-90) days. All of their conditions were improved after addition of Ruxolitinib. The median time of response was 7(5-14) days. The median follow-up was 208(33-412) days. Three patients(6.4%) died, and all of them died of severe pulmonary infection. Three patients (6.4%) had relapse of primary disease. The 6-month overall survival rate was 95.7%. Conclusion: Low-dose Ruxolitinib has good efficacy and safety in the treatment of cGVHD.

[Effect of KIR/HLA receptor-ligand mode on prognosis of single unrelated cord blood transplantation in patients with hematological malignancies]

目的

探讨自然杀伤细胞免疫球蛋白样受体（KIR）与人类白细胞抗原（HLA）受配体模式对血液病患者单份非血缘脐血移植（sUCBT）预后的影响。

方法

回顾性分析2012年7月至2018年6月270例接受sUCBT的血液病患者。移植前脐血及患者均进行HLA12个位点高分辨配型，选择移植物（脐血）的KIR均同时表达2DL1和2DL2/2DL3抑制性基因，根据患者KIR配体情况分为缺失组（C1/C1或C2/C2）和无缺失组（C1/C2）。

结果

270例血液病患者中男146例（54.1％），女124例（45.9％），中位年龄13（1～62）岁；缺失组174例（64.4％），无缺失组96例（35.6％）。全部患者均采用不含抗胸腺细胞球蛋白（ATG）清髓性预处理方案。缺失组、无缺失组粒细胞植入率均为98.9％（172/174、95/96），中位植入时间分别为16（10～41）d、17（11～33）d（P＝0.705）；血小板植入率分别为88.5％（154/174）、87.5％（84/96），中位植入时间分别为35（11～113）d、38.5（13～96）d（P＝0.317）；缺失组、无缺失组Ⅱ～Ⅳ级急性GVHD发生率分别为38.7％（95％CI 31.4％～45.9％）、50.0％（95％CI 39.6％～59.6％）（P＝0.075），多因素分析显示KIR配体缺失是影响Ⅱ～Ⅳ度急性GVHD发生的独立保护性因素（P＝0.036）。移植后3年累积复发率分别为17.7％（95％CI 11.7％～24.9％）、22.7％（95％CI14.4％～32.2％）（P＝0.288）。中位随访时间742（335～2 512）d，缺失组、无缺失组3年总生存率分别为72.1％（95％CI 64.1％～78.6％）、60.5％（95％CI 47.9％～69.2％）（χ²＝3.629，P＝0.079），3年无病生存率分别为64.9％（95％CI 56.2％～72.3％）、55.4％（95％CI 44.4％～65.0％）（χ²＝3.027，P＝0.082），移植后180 d 非复发死亡率分别为12.1％（95％CI 7.7％～17.4％）、16.7％（95％CI 10.0％～24.8％）（P＝0.328）。

结论

在不含ATG清髓性预处理sUCBT血液病治疗体系中，缺失抑制性KIR配体患者移植后急性GVHD发生率更低。

A predator-prey interaction between a marine Pseudoalteromonas sp. and Gram-positive bacteria

Predator-prey interactions play important roles in the cycling of marine organic matter. Here we show that a Gram-negative bacterium isolated from marine sediments (Pseudoalteromonas sp. strain CF6-2) can kill Gram-positive bacteria of diverse peptidoglycan (PG) chemotypes by secreting the metalloprotease pseudoalterin. Secretion of the enzyme requires a Type II secretion system. Pseudoalterin binds to the glycan strands of Gram positive bacterial PG and degrades the PG peptide chains, leading to cell death. The released nutrients, including PG-derived D-amino acids, can then be utilized by strain CF6-2 for growth. Pseudoalterin synthesis is induced by PG degradation products such as glycine and glycine-rich oligopeptides. Genes encoding putative pseudoalterin-like proteins are found in many other marine bacteria. This study reveals a new microbial interaction in the ocean.

Predator-prey interactions play important roles in the cycling of marine organic matter. Here the authors show that a Gram-negative bacterium isolated from marine sediments can kill and feed on Gram-positive bacteria by secreting a peptidoglycan-degrading enzyme.

[Comparison of umbilical cord blood transplantation and hematopoietic stem cell transplantation from HLA-matched sibling donors in the treatment of myelodysplastic syndrome-EB or acute myeloid leukemia with myelodysplasia-related changes]

目的

比较非血缘脐血干细胞移植（UCBT）与同胞HLA全相合供者造血干细胞移植（MSD-HSCT）治疗骨髓增生异常综合征伴原始细胞增多（MDS-EB）和急性髓系白血病伴骨髓增生异常相关改变（AML-MRC）的临床疗效。

方法

回顾性分析2011年2月至2017年12月接受UCBT/MSD-HSCT的MDS-EB/AML-MRC患者64例，其中MDS-EB 38例，AML-MRC 26例。

结果

①与MSD-HSCT组比较，UCBT组AML-MRC患者比例较高[52.8%（19/36）对25.0%（7/28），P=0.025]，中位年龄较低[13（1.5~52）岁对32（10~57）岁，P=0.001]。②UCBT组与MSD-HSCT组+42 d粒细胞植入率均为100%，中位植入时间分别为17.5（11~31）d、11.5（10~20）d；UCBT组+100 d血小板植入率为91.4%，中位植入时间为40（15~96）d，MSD-HSCT组+100 d血小板植入率为100.0%，中位植入时间为15（11~43）d。③UCBT组和MSD-HSCT组比较，+100 dⅡ~Ⅳ度、Ⅲ/Ⅳ度急性GVHD累积发生率、180 d移植相关死亡率、3年累积复发率、3年总生存率和3年无病生存率差异均无统计学意义（P>0.05）。④UCBT组3年慢性GVHD、重度慢性GVHD的累积发生率均低于MSD-HSCT组[28.3%（95% CI 13.4%~45.3%）对67.9%（95%CI 46.1%~82.4%），P=0.002；10.3%（95%CI 2.5%~24.8%）对50.0%（95%CI 30.0%~67.1%），P<0.001]；UCBT组3年无严重急慢性GVHD及无复发生存（GRFS）率明显高于MSD-HSCT组[55.0%（95%CI 36.0%~70.6%）对28.6%（95%CI 13.5%~45.6%），P=0.038]。

结论

UCBT治疗MDS-EB/AML-MRC患者可获得比MSD-HSCT更好的移植后生存质量。

[Efficacy analysis of unrelated cord blood transplantation in the treatment of refractory and relapsed adult acute leukemia]

目的

探讨非血缘脐血移植（UCBT）挽救治疗难治复发急性白血病（AL）患者的临床疗效和安全性。

方法

回顾性分析2009年11月至2017年5月22例行UCBT挽救治疗的难治复发成人AL患者的临床资料，全部患者采用清髓性预处理方案，均采用环孢素A/短程霉酚酸酯方案预防GVHD。

结果

①22例患者中男9例，女13例，中位年龄23（15~44）岁；中位体重52.5（43~82）kg。所有患者回输脐血有核细胞中位数为3.07（1.71~5.30）×10⁷/kg（受者体重），CD34⁺细胞中位数为1.60（0.63~3.04）×10⁵/kg（受者体重）。②移植后42 d髓系累积植入率为95.5%（95%CI 45.2%~99.7%），中位植入时间为19（13~27）d；移植后120 d血小板累积植入率为81.8%（95%CI 54.2%~93.6%），中位植入时间为42（20~164）d。③Ⅱ~Ⅳ度、Ⅲ~Ⅳ度急性GVHD发生率以及慢性GVHD 2年累积发生率分别为36.4%、13.6%和40.3%。④移植后180 d移植相关死亡率为22.7%；2年累积复发率为18.7%（95%CI 3.6%~42.5%），2年累积无病生存率及累积总生存率分别为53.7%和58.1%。

结论

对于常规化疗无效的难治复发成人AL患者，初步结果显示采用UCBT安全、有效。

[Comparison of unrelated cord blood transplantation and HLA-identical sibling peripheral blood stem cell transplantation for the treatment of adult hematological malignancies]

Objective: To compare the efficacy of unrelated cord blood transplantation (UCBT) and HLA-identical sibling peripheral blood stem cell transplantation (PBSCT) for the treatment of adult hematological malignancies. Methods: From April 2011 to December 2015, a total of 81 patients receiving single-unit UCBT and 57 patients receiving HLA-identical sibling PBSCT were enrolled in this study. All of the patients received myelablative conditioning. Cyclosporine combined with mycophenolate mofetil was adopted for GVHD prophylaxis. Results: The cumulative incidence of neutropil engraftment at day-42 was 95.0% and 100% in UCBT and sibling PBSCT groups, respectively (P=0.863) . Platelet engraftment at day 100 was 87.3% (95%CI 76.8%-93.1%) in UCBT group, which was significantly lower than that of sibling PBSCT group[98.2% (95%CI 87.3%-99.7%) ] (P=0.005) . There were no significant differences in terms of Ⅱ-Ⅳ acute GVHD or Ⅲ-Ⅳ acute GVHD in two groups (P=0.142, 0.521) . The 3-year chronic GVHD and extensive chronic GVHD were 14.9% (95%CI 5.2%-23.5%) and 11.2% (95%CI 2.9%-18.7%) , respectively in UCBT group, which was significantly lower than that of sibling PBSCT group[35.2% (95%CI 19.4%-47.8%) , 31.4% (95%CI 16.2%-43.9%) ] (P=0.008, 0.009) . The 3-year transplant-related mortality (TRM) was similar between two groups (30.1% vs 23.2%, P=0.464) . The relapse rate at 3-year in UCBT group[12.9% (95%CI 6.6%-21.5%) ]was significantly lower than that in sibling PBSCT group[24.3% (95%CI 13.5%-36.8%) ] (P=0.039) . There were no significant differences in terms of overall survival (OS) and disease-free survival (DFS) between two groups (58.6% vs 54.8%, P=0.634; 57.0% vs 52.4%, P=0.563) . But GVHD-free and relapse-free survival (GRFS) in UCBT group [55.7% (95%CI 44.1%-65.8%) ]was significantly higher than that of sibling PBSCT group[42.9% (95%CI 29.8%-55.3%) ] (P=0.047) . Conclusions: For adult hematological malignancies, the incidences of acute GVHD and TRM were similar between UCBT and sibling PBSCT recipients, and the incidences of chronic GVHD and relapse were lower in UCBT recipients. UCBT recipients had higher GRFS rate although OS and DFS were similar between two groups, which may reflect the real recovery and better quality of life following UCBT.

[Comparison of intensified myeloablative conditioning regime without antithymocytic globulin (ATG) with myeloablative conditioning regime for single-unit unrelated umbilical cord blood transplantation in hematological malignancies]

OBJECTIVE

To campare the effect and tolerance beween intensified myeloablative conditioning regime (IMCR) without antithymocyte globulin (ATG) and myeloablative conditioning regime (MCR) for single-unit unrelated umbilical cord blood transplantation (sUCBT) in hematological malignancies.

METHODS

The clinical data of 190 patients with hematological malignancies undergoing sUCBT between April 2000 and December 2013 at Department of Hematology, Anhui Provincial Hospital were retrospectively analyzed, of whom 156 received IMCR without ATG (IMCR group), including 79 patient receiving total body irradiation (TBI)/cytosine arabinoside (Ara-C)/cyclophosphamide (CY) regime, 47 receiving fludarabine (Flu)/busulfan (Bu)/CY regime, and 30 receiving Ara-C/Bu/CY regime, and all of the 156 received a combination of cyclosporine A (CsA) and mycophelonate mofetil (MMF) for the prophylaxis of graft-versus-host disease (GVHD); the remaining 34 patients received MCR (MCR group), 30 patients receiving Bu/CY regime, and 4 receiving TBI/CY regime, all using CsA/MMF±ATG or methotrexate (MTX) for the prophylaxis of GVHD. The two groups were compared in disease status at the time of transplantation, characteristics of graft, transplantation effect, and transplantation-related complications.

RESULTS

There were no statistically significant differences between the two groups in gender, disease type, human leukocyte antigen match, ABO blood type match, and disease status at the time of transplantation (all P>0.05). The median age and body weight at transplantation in the IMCR group were significantly higher than those in the MCR group (13 years vs 9 years, P=0.003; 44 kg vs 26 kg, P=0.000). The median doses of infused total nucleated cells (×10(7)/kg) and CD34(+) cells (×10(5)/kg) in the IMCR group were significantly lower than in the MCR group (3.87 vs 4.99, P=0.002; 2.00 vs 3.17, P=0.000). The cumulative incidence of myeloid engraftment on the 42th day and platelet engraftment on the 120th day in the IMCR group were remarkably higher than in the MCR group [96.33%(95%CI: 96.27%-96.39%)vs 82.30%(95%CI: 80.67%-83.93%), P=0.000; 86.44%(95%CI: 86.28%-86.60%)vs 51.17%(95%CI: 49.02%-53.32%), P=0.002]. There were no statistically significant differences in the incidences of grade Ⅱ to Ⅳ acute GVHD, grade Ⅲ to Ⅳ acute GVHD, and 2-year chronic GVHD(P=0.482, 0.928, 0.579). The incidence of pre-engraftment syndrome in the IMCR group was higher than in the MCR group(82.70% vs 47.06%, P=0.000). And 180-day transplantation-related mortality (TRM) in the IMCR group was lower than that in the MCR group [20.50%(95%CI: 20.28%-20.71%)vs 42.20% (95%CI: 41.32%-45.09%), P=0.004]. Up to October 2015, with a median follow-up of 44.2(22.7-188.9)months, the estimated 3-year overall survival and disease-free survival in the IMCR group were both significantly higher than those in the MCR group (62.90% vs 34.10%, P=0.000; 58.60% vs 34.10%, P=0.001).

CONCLUSION

IMCR without ATG may improve the engraftment without increasing complications, reduce early transplantation-related mortality, and improve survival.

Characterization of a New S8 serine Protease from Marine Sedimentary Photobacterium sp. A5-7 and the Function of Its Protease-Associated Domain

Bacterial extracellular proteases are important for bacterial nutrition and marine sedimentary organic nitrogen degradation. However, only a few proteases from marine sedimentary bacteria have been characterized. Some subtilases have a protease-associated (PA) domain inserted in the catalytic domain. Although structural analysis and deletion mutation suggests that the PA domain in subtilases is involved in substrate binding, direct evidence to support this function is still absent. Here, a protease, P57, secreted by Photobacterium sp. A5-7 isolated from marine sediment was characterized. P57 could hydrolyze casein, gelatin and collagen. It showed the highest activity at 40°C and pH 8.0. P57 is a new subtilase, with 63% sequence identity to the closest characterized protease. Mature P57 contains a catalytic domain and an inserted PA domain. The recombinant PA domain from P57 was shown to have collagen-binding ability, and Phe349 and Tyr432 were revealed to be key residues for collagen binding in the PA domain. This study first shows direct evidence that the PA domain of a subtilase can bind substrate, which provides a better understanding of the function of the PA domain of subtilases and bacterial extracellular proteases from marine sediment.

Pilot-Scale Production and Thermostability Improvement of the M23 Protease Pseudoalterin from the Deep Sea Bacterium Pseudoalteromonas sp. CF6-2

Pseudoalterin is the most abundant protease secreted by the marine sedimental bacterium Pseudoalteromonas sp. CF6-2 and is a novel cold-adapted metalloprotease of the M23 family. Proteases of the M23 family have high activity towards peptidoglycan and elastin, suggesting their promising biomedical and biotechnological potentials. To lower the fermentive cost and improve the pseudoalterin production of CF6-2, we optimized the fermentation medium by using single factor experiments, added 0.5% sucrose as a carbon source, and lowered the usage of artery powder from 1.2% to 0.6%. In the optimized medium, pseudoalterin production reached 161.15 ± 3.08 U/mL, 61% greater than that before optimization. We further conducted a small-scale fermentation experiment in a 5-L fermenter and a pilot-scale fermentation experiment in a 50-L fermenter. Pseudoalterin production during pilot-scale fermentation reached 103.48 ± 8.64 U/mL, 77% greater than that before the medium was optimized. In addition, through single factor experiments and orthogonal tests, we developed a compound stabilizer for pseudoalterin, using medically safe sugars and polyols. This stabilizer showed a significant protective effect for pseudoalterin against enzymatic thermal denaturation. These results lay a solid foundation for the industrial production of pseudoalterin and the development of its biomedical and biotechnological potentials.

[Pathogens and clinical characteristics of bacterial infection in hematology department between 2010 and 2014]

OBJECTIVE

To analyze the characteristics of distribution and drug resistance of bacterial infection in several different parts of hematology department inpatients of Anhui Provincial Hospital from January 2010 to December 2014, including patients who had received hematopoietic stem cell transplantation (HSCT).

METHODS

Anti-microbial susceptibility test was done by Kirby-Bauer method and automated systems and the data were analysed by WHONET 5.6 software.

RESULTS

A total of 3 312 copies of inspection samples were analyzed, including 2 716 (82%) blood samples and other 596 specimens (18%). 634 bacterial strains were isolated from 3 312 samples (19.14%) including 488 samples (76.97%) from blood culture. 427 (67.35%) bacterial strains were gram-negative, and the other 207 (32.65%) were gram-positive. Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa were most common gram-negative bacterial and the resistant rates to imipenem were 0.8%, 11.8% and 3.3%, respectively. Detection rates of Extended-spectrum beta-lactamases in Escherichia coli and Klebsiella pneumoniae were 83.9% and 75.0%, respectively. At the same time, Coagulase negative Staphylococcus, Streptococcus and Enterococcus were most common kinds of gram-positive bacteria. Methicillin-resistant coagulase negative staphylococcus accounted for 65.9% antibiotic resistance. No vancomycin and/or linezolid and/or tigecycline resistant strains of Staphylococcus spp. and Enterococcus spp. were found in those patients.

CONCLUSION

Patients with hematology diseases had a higher risk of bacterial infections, mainly caused by Gram-negative bacteria. There are different distributions of bacterial in different wards.

Development of a Cold-Adapted Pseudoalteromonas Expression System for the Pseudoalteromonas Proteins Intractable for the Escherichia coli System

Although the Escherichia coli expression system is the most commonly used expression system, some proteins are still difficult to be expressed by this system, such as proteins with high thermolability and enzymes that cannot mature by autoprocessing. Therefore, it is necessary to develop alternative expression systems. In this study, a cold-adapted Pseudoalteromonas expression system was developed. A shuttle vector was constructed, and a conjugational transfer system between E. coli and psychrophilic strain Pseudoalteromonas sp. SM20429 was established. Based on the shuttle vector, three reporter vectors were constructed to compare the strength of the cloned promoters at low temperature. The promoter of xylanase gene from Pseudoalteromonas sp. BSi20429 was chosen due to its high activity at 10–15°C. An expression vector pEV containing the chosen promoter, multiple cloning sites and a His tag was constructed for protein expression and purification. With pEV as expression vector and SM20429 as the host, a cold-adapted protease, pseudoalterin, which cannot be maturely expressed in E. coli, was successfully expressed as an active extracellular enzyme when induced by 2% oat spelt xylan at 15°C for 48 h. Recombinant pseudoalterin purified from the culture by Ni affinity chromatography had identical N-terminal sequence, similar molecular mass and substrate specificity as the native pseudoalterin. In addition, another two cold-adapted enzymes were also successfully expressed by this system. Our results indicate that this cold-adapted Pseudoalteromonas expression system will provide an alternative choice for protein expression, especially for the Pseudoalteromonas proteins intractable for the E. coli system.

Salvaged single-unit cord blood transplantation for 26 patients with hematologic malignancies not in remission

Treatments for patients with hematologic malignancies not in remission are limited, but a few clinical studies have investigated the effects of salvaged unrelated cord blood transplantation (CBT). We retrospectively studied 19 patients with acute leukemia, 5 with myelodysplastic syndrome (MDS with refractory anemia with excess blasts [RAEB]), and 2 with non-Hodgkin's lymphoma who received 1 CBT unit ≤2 loci human leukocyte antigen (HLA)-mismatched after undergoing myeloablative conditioning regimens between July 2005 and July 2014. All of them were in non-remission before transplantation. The infused total nucleated cell (TNC) dose was 4.07 (range 2.76-6.02)×10⁷/kg and that of CD34⁺ stem cells was 2.08 (range 0.99-8.65)×10⁵/kg. All patients were engrafted with neutrophils that exceeded 0.5×10⁹/L on median day +17 (range 14-37 days) and had platelet counts of >20×10⁹/L on median day +35 (range 17-70 days). Sixteen patients (61.5%) experienced pre-engraftment syndrome (PES), and six (23.1%) patients progressed to acute graft-versus-host disease (GVHD). The cumulative incidence rates of II-IV acute GVHD and chronic GVHD were 50% and 26.9%, respectively. After a median follow-up of 27 months (range 5-74), 14 patients survived and 3 relapsed. The estimated 2-year overall survival (OS), disease-free survival (DFS), and non-relapse mortality (NRM) rates were 50.5%, 40.3%, and 35.2%, respectively. Salvaged CBT might be a promising modality for treating hematologic malignancies, even in patients with a high leukemia burden.

Mechanistic insight into the elastin degradation process by the metalloprotease myroilysin from the deep-sea bacterium Myroides profundi D25

Elastases have been widely studied because of their important uses as medicine and meat tenderizers. However, there are relatively few studies on marine elastases. Myroilysin, secreted by Myroides profundi D25 from deep-sea sediment, is a novel elastase. In this study, we examined the elastin degradation mechanism of myroilysin. When mixed with insoluble bovine elastin, myroilysin bound hydrophobically, suggesting that this elastase may interact with the hydrophobic domains of elastin. Consistent with this, analysis of the cleavage pattern of myroilysin on bovine elastin and recombinant tropoelastin revealed that myroilysin preferentially cleaves peptide bonds with hydrophobic residues at the P1 and/or P1′ positions. Scanning electron microscopy (SEM) of cross-linked recombinant tropoelastin degraded by myroilysin showed preferential damages of spherules over cross-links, as expected for a hydrophobic preference. The degradation process of myroilysin on bovine elastin fibres was followed by light microscopy and SEM, revealing that degradation begins with the formation of crevices and cavities at the fibre surface, with these openings increasing in number and size until the fibre breaks into small pieces, which are subsequently fragmented. Our results are helpful for developing biotechnological applications for myroilysin.

Filamentous phages prevalent in Pseudoalteromonas spp. confer properties advantageous to host survival in Arctic sea ice

Sea ice is one of the most frigid environments for marine microbes. In contrast to other ocean ecosystems, microbes in permanent sea ice are space confined and subject to many extreme conditions, which change on a seasonal basis. How these microbial communities are regulated to survive the extreme sea ice environment is largely unknown. Here, we show that filamentous phages regulate the host bacterial community to improve survival of the host in permanent Arctic sea ice. We isolated a filamentous phage, f327, from an Arctic sea ice Pseudoalteromonas strain, and we demonstrated that this type of phage is widely distributed in Arctic sea ice. Growth experiments and transcriptome analysis indicated that this phage decreases the host growth rate, cell density and tolerance to NaCl and H2O2, but enhances its motility and chemotaxis. Our results suggest that the presence of the filamentous phage may be beneficial for survival of the host community in sea ice in winter, which is characterized by polar night, nutrient deficiency and high salinity, and that the filamentous phage may help avoid over blooming of the host in sea ice in summer, which is characterized by polar day, rich nutrient availability, intense radiation and high concentration of H2O2. Thus, while they cannot kill the host cells by lysing them, filamentous phages confer properties advantageous to host survival in the Arctic sea ice environment. Our study provides a foremost insight into the ecological role of filamentous phages in the Arctic sea ice ecosystem.

Successful early unmanipulated haploidentical transplantation with reduced-intensity conditioning for primary graft failure after cord blood transplantation in hematologic malignancy patients

Primary graft failure (pGF) is a frequent complication following cord blood transplantation (CBT). For those patients who will not experience autologous recovery, salvage transplantation should be performed as early as possible. However, standardized treatment protocols for pGF, such as the optimal stem cell source, preparative regimen and the ideal time for salvage transplantation, have yet to be determined. Therefore, we analyzed 17 hematologic malignancy patients who received unmanipulated haploidentical peripheral blood (PB) and BM transplantation with reduced-intensity conditioning (RIC) as a salvage therapy for pGF after CBT. The median interval between the two transplantations was 38 days. The RIC regimen for salvage transplantation consisted of fludarabine, antithymocyte globulin, CY and low-dose TBI. The neutrophil and plt engraftments were achieved in 14 (82.4%) and 13 (76.4%) patients, respectively. The cumulative incidences of grades II-IV and grades III-IV aGVHD were 35.3% and 17.6%, respectively. The cumulative incidence of chronic GVHD was 29.4%. After a median follow-up of 43 months, 10 of 17 patients remained alive in CR. The cumulative incidence of TRM at 180 days was 29.4%. The probability of 3-year OS and leukemia-free survival was 57.5%. Our results show that unmanipulated haploidentical PB and BM transplantation under a RIC regimen is an effective treatment for pGF after CBT.

The effect on maternal temperature of delaying initiation of the epidural component of combined spinal-epidural analgesia for labor: a pilot study

BACKGROUND

Labor epidural analgesia is associated with maternal hyperthermia. This pilot study compared the effects on maternal temperature during labor of different timing of initiation of the epidural component of combined spinal-epidural analgesia.

METHODS

After induction of analgesia with intrathecal bupivacaine 2 mg and fentanyl 20 μg, healthy term nulliparas in spontaneous labor were randomized to receive immediate epidural analgesia (n=26) or delayed epidural analgesia after the return of pain (n=28), by patient-controlled epidural analgesia with 0.125% bupivacaine and fentanyl 1 μg/mL. Maternal tympanic temperature, visual analog scale pain score and dermatome block level were measured hourly during labor.

RESULTS

The duration of labor for most parturients (83.3%) was <5 h. Mean maternal temperature gradually increased over time but did not significantly differ from either from baseline or between the two groups. There was no significant difference in the incidence of maternal fever (≥38°C) between the two groups. At 2 h post spinal analgesia the visual analog scale score was higher (P=0.03) and the dermatome block level was lower (P=0.005) in the delayed epidural analgesia group compared to the immediate epidural analgesia group.

CONCLUSIONS

Delaying the epidural component of combined spinal-epidural analgesia did not significantly affect maternal temperature in the study population of whom 83.3% had a labor of <5 h. However, this study was underpowered to detect a difference in the incidence of fever and a larger prospective study is required.

Effects of intrathecal and i.v. small-dose sufentanil on the median effective dose of intrathecal bupivacaine for Caesarean section

BACKGROUND

Spinal anaesthesia with bupivacaine combined with sufentanil has been widely used for Caesarean section. However, the main site of action (spinal vs central) of intrathecal (IT) sufentanil is controversial. The aim of this study was to examine the predominant mechanism of action of IT, small-dose sufentanil when added to bupivacaine for Caesarean section, by comparing the effects of IT and i.v. sufentanil 2.5 microg on the median effective dose (ED50) of bupivacaine.

METHODS

Ninety parturients undergoing elective Caesarean section with a combined spinal-epidural technique were enrolled into this prospective, double-blind, up-down sequential allocation study. According to the up-down sequential allocation, parturients received varying doses of bupivacaine alone (C group) or co-administered with i.v. sufentanil 2.5 microg group (IVS group; n = 30) or IT sufentanil 2.5 microg group (ITS group; n = 30). The possible maternal or neonatal adverse effects were also recorded.

RESULTS

The ED(50) of bupivacaine was 6.3 mg (95% CI 6.2-6.5) in the C group, 5.2 mg (95% CI 5.1-5.4) in the IVS group, and 3.0 mg (95% CI 2.9-3.1) in the ITS group. The ED50 in the ITS group was significantly lower as compared with the other two groups (P < 0.0005). With the exception of pruritus that exclusively occurred in the ITS group (P = 0.011, compared with the other two groups), no significant differences among groups were observed regarding the frequencies of the maternal or neonatal adverse effects.

CONCLUSIONS

Compared with an equal dose of sufentanil i.v., intrathecally administered sufentanil 2.5 microg has a significant local anaesthetic-sparing effect via a predominantly spinal mechanism for Caesarean section.

Coaxing bone marrow stromal mesenchymal stem cells towards neuronal differentiation: progress and uncertainties

Multipotent adult stem cells capable of developing into particular neuronal cell types have great potential for autologous cell replacement therapy for central nervous system neurodegenerative disorders and traumatic injury. Bone marrow-derived stromal mesenchymal stem cells (BMSCs) appear to be attractive starting materials. One question is whether BMSCs could be coaxed to differentiate in vitro along neuronal or glial lineages that would aid their functional integration post-transplantation, while reducing the risk of malignant transformation. Recent works suggest that BMSCs could indeed be differentiated in vitro to exhibit some cellular and physiological characteristics of neural cell lineages, but it is not likely to be achievable with simple chemical treatments. We discussed recent findings pertaining to efforts in neuronal differentiation of BMSCs in vitro, and results obtained when these were transplanted in vivo.

APC/C regulation of axonal growth and synaptic functions in postmitotic neurons: the Liprin- $${\varvec \alpha}$$ connection

Protein ubiquitination has critical roles in neuronal physiology and defects in protein ubiquitination have been implicated in neurodegenerative pathology. The anaphase-promoting complex/cyclosome (APC/C) is one of two key E3 ubiquitin ligase complexes that functions in regulating cell cycle transitions in proliferating cells by acting on cyclins and components of the mitotic/meiotic apparatus. Documentation of APC/C's action beyond cell division is sparse. In the past year, however, novel and surprising roles for APC/C in postmitotic neurons, particularly in the modulation of axonal growth and synaptic functions, have been revealed. APC/C and its activator Cdh-1 are found in good abundance in neurons, and these seem to function at different cellular locations, modulating apparently diverse processes such as axonal growth and synaptic function. Interestingly, there also appears to be a single link to these apparently divergent actions of APC/C in neurons--the multi-domain, multi-functional scaffolding protein Liprin-alpha which is an APC/C substrate.

Protein trafficking mechanisms associated with neurite outgrowth and polarized sorting in neurons

Neuronal differentiation in vitro and in vivo involves coordinated changes in the cellular cytoskeleton and protein trafficking processes. I review here recent progress in our understanding of the membrane trafficking aspects of neurite outgrowth of neurons in culture and selective microtubule-based polarized sorting in fully polarized neurons, focusing on the involvement of some key molecules. Early neurite outgrowth appears to involve the protein trafficking machineries that are responsible for constitutive trans-Golgi network (TGN) to plasma membrane exocytosis, utilizing transport carrier generation mechanisms, SNARE proteins, Rab proteins and tethering mechanisms that are also found in non-neuronal cells. This vectorial TGN-plasma membrane traffic is directed towards several neurites, but can be switch to concentrate on the growth of a single axon. In a mature neuron, polarized targeting to the specific axonal and dendritic domains appears to involve selective microtubule-based mechanisms, utilizing motor proteins capable of distinguishing microtubule tracks to different destinations. The apparent gaps in our knowledge of these related protein transport processes will be highlighted.

A membrane protein enriched in endoplasmic reticulum exit sites interacts with COPII

Although all mammalian COPII components have now been cloned, little is known of their interactions with other regulatory proteins involved in exit from the endoplasmic reticulum (ER). We report here that a mammalian protein (Yip1A) that is about 31% identical to S. cerevisiae and which interacts with and modulates COPII-mediated ER-Golgi transport. Yip1A transcripts are ubiquitously expressed. Transcripts of a related mammalian homologue, Yip1B, are found specifically in the heart. Indirect immunofluorescence microscopy revealed that Yip1A is localized to vesicular structures that are concentrated at the perinuclear region. The structures marked by Yip1A co-localized with Sec31A and Sec13, components of the COPII coat protein complex. Immunoelectron microscopy also showed that Yip1A co-localizes with Sec13 at ER exit sites. Overexpression of the hydrophilic N terminus of Yip1A arrests ER-Golgi transport of the vesicular stomatitis G protein and causes fragmentation and dispersion of the Golgi apparatus. A glutathione S-transferase fusion protein with the hydrophilic N terminus of Yip1A (GST-Yip1A) is able to bind to and deplete vital components from rat liver cytosol that is essential for in vitro vesicular stomatitis G transport. Peptide sequence analysis of cytosolic proteins that are specifically bound to GST-Yip1A revealed, among other proteins, mammalian COPII components Sec23 and Sec24. A highly conserved domain at the N terminus of Yip1A is required for Sec23/Sec24 interaction. Our results suggest that Yip1A is involved in the regulation of ER-Golgi traffic at the level of ER exit sites.

Cellular COPII proteins are involved in production of the vesicles that form the poliovirus replication complex

Poliovirus (PV) replicates its genome in association with membranous vesicles in the cytoplasm of infected cells. To elucidate the origin and mode of formation of PV vesicles, immunofluorescence labeling with antibodies against the viral vesicle marker proteins 2B and 2BC, as well as cellular markers of the endoplasmic reticulum (ER), anterograde transport vesicles, and the Golgi complex, was performed in BT7-H cells. Optical sections obtained by confocal laser scanning microscopy were subjected to a deconvolution process to enhance resolution and signal-to-noise ratio and to allow for a three-dimensional representation of labeled membrane structures. The mode of formation of the PV vesicles was, on morphological grounds, similar to the formation of anterograde membrane traffic vesicles in uninfected cells. ER-resident membrane markers were excluded from both types of vesicles, and the COPII components Sec13 and Sec31 were both found to be colocalized on the vesicular surface, indicating the presence of a functional COPII coat. PV vesicle formation during early time points of infection did not involve the Golgi complex. The expression of PV protein 2BC or the entire P2 and P3 genomic region led to the production of vesicles carrying a COPII coat and showing the same mode of formation as vesicles produced after PV infection. These results indicate that PV vesicles are formed at the ER by the cellular COPII budding mechanism and thus are homologous to the vesicles of the anterograde membrane transport pathway.

Evidence for prebudding arrest of ER export in animal cell mitosis and its role in generating Golgi partitioning intermediates

During mitosis the interconnected Golgi complex of animal cells breaks down to produce both finely dispersed elements and discrete vesiculotubular structures. The endoplasmic reticulum (ER) plays a controversial role in generating these partitioning intermediates and here we highlight the importance of mitotic ER export arrest in this process. We show that experimental inhibition of ER export (by microinjecting dominant negative Sar1 mutant proteins) is sufficient to induce and maintain transformation of Golgi cisternae to vesiculotubular remnants during interphase and telophase, respectively. We also show that buds on the ER, ER exit sites and COPII vesicles are markedly depleted in mitotic cells and COPII components Sec23p, Sec24p, Sec13p and Sec31p redistribute into the cytosol, indicating ER export is inhibited at an early stage. Finally, we find a markedly uneven distribution of Golgi residents over residual exit sites of metaphase cells, consistent with tubulovesicular Golgi remnants arising by fragmentation rather than redistribution via the ER. Together, these results suggest selective recycling of Golgi residents, combined with prebudding cessation of ER export, induces transformation of Golgi cisternae to vesiculotubular remnants in mitotic cells. The vesiculotubular Golgi remnants, containing populations of slow or nonrecycling Golgi components, arise by fragmentation of a depleted Golgi ribbon independently from the ER.

ADAMTS: a novel family of extracellular matrix proteases

ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs) is a novel family of extracellular proteases found in both mammals and invertebrates. Members of the family may be distinguished from the ADAM (a disintegrin and metalloprotease) family members based on the multiple copies of thrombospondin 1-like repeats they carry. With at least nine members in mammals alone, the ADAMTS family members are predicted by their structural domains to be extracellular matrix (ECM) proteins with a wide range of activities and functions distinct from members of the ADAM family that are largely anchored on the cell surface. ADAMTS2 is a procollagen N-proteinase, and the mutations of its gene are responsible for Human Ehlers-Danlos syndrome type VII C and bovine dermatosparaxis. ADAMTS4 and ADAMTS5 are aggrecanases implicated in the degradation of cartilage aggrecan in arthritic diseases. Other members of the ADAMTS family have also been implicated in roles during embryonic development and angiogenesis. Current and future studies on this emerging group of ECM proteases may provide important insights into developmental or pathological processes involving ECM remodeling.

The syntaxins

SUMMARY

The SNARE hypothesis predicts that a family of SNAP receptors are localized to and function in diverse intracellular membrane compartments where membrane fusion processes take place. Syntaxins, the prototype family of SNARE proteins, have a carboxy-terminal tail-anchor and multiple coiled-coil domains. There are 15 members of the syntaxin family in the human genome and 7 syntaxin-like genes in the yeast Saccharomyces cerevisiae. In conjunction with other SNAREs and with the cytoplasmic NSF and SNAP proteins, syntaxins mediate vesicle fusion in diverse vesicular transport processes along the exocytic and the endocytic pathway. They are crucial components that both drive and provide specificity to the myriad vesicular fusion processes that characterize the eukaryotic cell.

Mammalian homologues of yeast sec31p. An ubiquitously expressed form is localized to endoplasmic reticulum (ER) exit sites and is essential for ER-Golgi transport

The yeast coat protein II (COPII) is responsible for vesicle budding from the endoplasmic reticulum (ER). Mammalian functional homologues for all yeast COPII components, except for Sec31p, have been reported. We have cloned a mammalian cDNA whose product (Sec31A) is about 26% identical to Saccharomyces cerevisiae Sec31p. Data base searches also revealed another partial sequence encoding a polypeptide (Sec31B) that is 40% identical to Sec31A. Northern analysis revealed that Sec31A transcripts are ubiquitously and abundantly expressed, while Sec31B transcripts are particularly enriched in the testis and thymus, but present in very low levels in other tissues. Sec31A is localized to vesicular structures that scatter throughout the cell but are concentrated at the perinuclear region. The structures marked by Sec31A contain Sec13, a component of COPII that is well characterized to mark the ER exit sites. Immunoelectron microscopy revealed that Sec31A colocalizes with Sec13 in structures with extensive vesicular-tubular profiles. Antibodies raised against a C-terminal portion of Sec31A co-precipitate Sec13 and inhibit ER-Golgi transport of temperature-arrested vesicular stomatitis G protein in a semi-intact cell assay. Cytosol immunodepleted of Sec31A failed to support vesicular stomatitis G protein transport, which can be rescued by a high molecular weight fraction of the cytosol containing both Sec31A and Sec13. We conclude that Sec31A represents a functional mammalian homologue of yeast Sec31p.

Localization and recycling of gp27 (hp24gamma3): complex formation with other p24 family members

We report here the characterization of gp27 (hp24gamma3), a glycoprotein of the p24 family of small and abundant transmembrane proteins of the secretory pathway. Immunoelectron and confocal scanning microscopy show that at steady state, gp27 localizes to the cis side of the Golgi apparatus. In addition, some gp27 was detected in COPI- and COPII-coated structures throughout the cytoplasm. This indicated cycling that was confirmed in three ways. First, 15 degrees C temperature treatment resulted in accumulation of gp27 in pre-Golgi structures colocalizing with anterograde cargo. Second, treatment with brefeldin A caused gp27 to relocate into peripheral structures positive for both KDEL receptor and COPII. Third, microinjection of a dominant negative mutant of Sar1p trapped gp27 in the endoplasmic reticulum (ER) by blocking ER export. Together, this shows that gp27 cycles extensively in the early secretory pathway. Immunoprecipitation and coexpression studies further revealed that a significant fraction of gp27 existed in a hetero-oligomeric complex. Three members of the p24 family, GMP25 (hp24alpha2), p24 (hp24beta1), and p23 (hp24delta1), coprecipitated in what appeared to be stochiometric amounts. This heterocomplex was specific. Immunoprecipitation of p26 (hp24gamma4) failed to coprecipitate GMP25, p24, or p23. Also, very little p26 was found coprecipitating with gp27. A functional requirement for complex formation was suggested at the level of ER export. Transiently expressed gp27 failed to leave the ER unless other p24 family proteins were coexpressed. Comparison of attached oligosaccharides showed that gp27 and GMP25 recycled differentially. Only a very minor portion of GMP25 displayed complex oligosaccharides. In contrast, all of gp27 showed modifications by medial and trans enzymes at steady state. We conclude from these data that a portion of gp27 exists as hetero-oligomeric complexes with GMP25, p24, and p23 and that these complexes are in dynamic equilibrium with individual p24 proteins to allow for differential recycling and distributions.

A family of mammalian proteins homologous to yeast Sec24p

The Sec23p/Sec24p complex is a component of yeast coat protein II (COPII), the coat protein complex responsible for vesicle budding from the endoplasmic reticulum (ER). Database searches and molecular cloning reveal that four different mammalian Sec24p-like proteins exist, all with about 20% amino acid identity with the yeast Sec24p. Sec24A and Sec24B share about 50% amino acid identity. Sec24D is cloned by screening a human pancreas of cDNA library with an expressed sequence tag (EST) fragment that is homologous to, but distinct from, Sec24A and Sec24B. Sec24D shares about 50% amino acid identity with the gene product of KIAA0079, which we have designated as Sec24C. These mammalian Sec24s appear to form two subclasses based on homology. Sec24A/B and Sec24C/D share about 20% identity with each other and with the yeast Sec24p. The Sec24 sequences also share weak but significant homology to the mammalian Sec23A and Sec23B. Northern blot analysis revealed that Sec24C is ubiquitously expressed. Although Sec24D transcripts are detectable in all tissues examined, they are selectively enriched in certain tissues, particularly placenta and pancreas. myc-tagged Sec24C and sec24D colocalized with Sec13, another COPII component. This colocalization suggests that Sec24C and Sec24D are indeed associated with COPII structures on membranes of the ER-Golgi boundary. The existence of at least four forms of Sec24 in mammalian cells suggest that multiple forms of COPII complex may be involved in ER export.

Forward and retrograde trafficking in mitotic animal cells. ER-Golgi transport arrest restricts protein export from the ER into COPII-coated structures

Protein transport arrest occurs between the ER and Golgi stack of mitotic animal cells, but the location of this block is unknown. In this report we use the recycling intermediate compartment protein ERGIC 53/p58 and the plasma membrane protein CD8 to establish the site of transport arrest. Recycled ERGIC 53/p58 and newly synthesised CD8 accumulate in ER cisternae but not in COPII-coated export structures or more distal sites. During mitosis the tubulovesicular ER-related export sites were depleted of the COPII component Sec13p, as shown by immunoelectron microscopy, indicating that COPII budding structures are the target for mitotic inhibition. The extent of recycling of Golgi stack residents was also investigated. In this study we used oligosaccharide modifications on CD8 trapped in the ER of mitotic cells as a sensitive assay for recycling of Golgi stack enzymes. We find that modifications conferred by the Golgi stack-resident GalNac transferase do occur on newly synthesised CD8, but these modifications are entirely due to newly synthesised transferase rather than to enzyme recycled from the Golgi stack. Taken together our findings establish for the first time that the site of ER-Golgi transport arrest of mitotic cells is COPII budding structures, and they clearly speak against a role for recycling in partitioning of Golgi stack proteins via translocation to the ER.

Morphological and functional association of Sec22b/ERS-24 with the pre-Golgi intermediate compartment

Yeast Sec22p participates in both anterograde and retrograde vesicular transport between the endoplasmic reticulum (ER) and the Golgi apparatus by functioning as a v-SNARE (soluble N-ethylmaleimide-sensitive factor [NSF] attachment protein receptor) of transport vesicles. Three mammalian proteins homologous to Sec22p have been identified and are referred to as Sec22a, Sec22b/ERS-24, and Sec22c, respectively. The existence of three homologous proteins in mammalian cells calls for detailed cell biological and functional examinations of each individual protein. The epitope-tagged forms of all three proteins have been shown to be primarily associated with the ER, although functional examination has not been carefully performed for any one of them. In this study, using antibodies specific for Sec22b/ERS-24, it is revealed that endogenous Sec22b/ERS-24 is associated with vesicular structures in both the perinuclear Golgi and peripheral regions. Colabeling experiments for Sec22b/ERS-24 with Golgi mannosidase II, the KDEL receptor, and the envelope glycoprotein G (VSVG) of vesicular stomatitis virus (VSV) en route from the ER to the Golgi under normal, brefeldin A, or nocodazole-treated cells suggest that Sec22b/ERS-24 is enriched in the pre-Golgi intermediate compartment (IC). In a well-established semi-intact cell system that reconstitutes transport from the ER to the Golgi, transport of VSVG is inhibited by antibodies against Sec22b/ERS-24. EGTA is known to inhibit ER-Golgi transport at a stage after vesicle/transport intermediate docking but before the actual fusion event. Antibodies against Sec22b/ERS-24 inhibit ER-Golgi transport only when they are added before the EGTA-sensitive stage. Transport of VSVG accumulated in pre-Golgi IC by incubation at 15 degreesC is also inhibited by Sec22b/ERS-24 antibodies. Morphologically, VSVG is transported from the ER to the Golgi apparatus via vesicular intermediates that scatter in the peripheral as well as the Golgi regions. In the presence of antibodies against Sec22b/ERS-24, VSVG is seen to accumulate in these intermediates, suggesting that Sec22b/ERS-24 functions at the level of the IC in ER-Golgi transport.

The recycling pathway of protein ERGIC-53 and dynamics of the ER-Golgi intermediate compartment

To establish recycling routes in the early secretory pathway we have studied the recycling of the ER-Golgi intermediate compartment (ERGIC) marker ERGIC-53 in HepG2 cells. Immunofluorescence microscopy showed progressive concentration of ERGIC-53 in the Golgi area at 15 degreesC. Upon rewarming to 37 degreesC ERGIC-53 redistributed into the cell periphery often via tubular processes that largely excluded anterograde transported albumin. Immunogold labeling of cells cultured at 37 degreesC revealed ERGIC-53 predominantly in characteristic beta-COP-positive tubulo-vesicular clusters both near the Golgi apparatus and in the cell periphery. Concentration of ERGIC-53 at 15 degreesC resulted from both accumulation of ERGIC-53 in the ERGIC and movement of ERGIC membranes closer to the Golgi apparatus. Upon rewarming to 37 degreesC the labeling of ERGIC-53 in the ERGIC rapidly returned to normal levels whereas ERGIC-53's labeling in the cis-Golgi was unchanged. Temperature manipulations had no effect on the average number of ERGIC-53 clusters. Density gradient centrifugation indicated that the surplus ERGIC-53 accumulating in the ERGIC at 15 degreesC was rapidly transported to the ER upon rewarming. These results suggest that the ERGIC is a dynamic membrane system composed of a constant average number of clusters and that the major recycling pathway of ERGIC-53 bypasses the Golgi apparatus.

A novel synaptobrevin/VAMP homologous protein (VAMP5) is increased during in vitro myogenesis and present in the plasma membrane

cDNA clones encoding a novel protein (VAMP5) homologous to synaptobrevins/VAMPs are detected during database searches. The predicted 102-amino acid VAMP5 harbors a 23-residue hydrophobic region near the carboxyl terminus and exhibits an overall amino acid identity of 33% with synaptobrevin/VAMP1 and 2 and cellubrevin. Northern blot analysis reveals that the mRNA for VAMP5 is preferentially expressed in the skeletal muscle and heart, whereas significantly lower levels are detected in several other tissues but not in the brain. During in vitro differentiation (myogenesis) of C2C12 myoblasts into myotubes, the mRNA level for VAMP5 is increased approximately 8- to 10-fold. Immunoblot analysis using antibodies specific for VAMP5 shows that the protein levels are also elevated approximately 6-fold during in vitro myogenesis of C2C12 cells. Indirect immunofluorescence microscopy and immunoelectron microscopy reveal that VAMP5 is associated with the plasma membrane as well as intracellular perinuclear and peripheral vesicular structures of myotubes. Epitope-tagged versions of VAMP5 are similarly targeted to the plasma membrane.

Alpha-SNAP but not gamma-SNAP is required for ER-Golgi transport after vesicle budding and the Rab1-requiring step but before the EGTA-sensitive step

N-ethylmaleimide-sensitive factor (NSF) and soluble NSF attachment proteins (SNAPs) have been implicated in diverse vesicular transport events; yet their exact role and site of action remain to be established. Using an established in vitro system, we show that antibodies against alpha-SNAP inhibit vesicle transport from the ER to the cis-Golgi and that recombinant alpha-SNAP enhances/stimulates the process. Cytosol immunodepleted of alpha-SNAP does not support normal transport unless supplemented with recombinant alpha-SNAP but not gamma-SNAP. In marked contrast, cytosol immunodepleted of gamma-SNAP supports ER-Golgi transport to the normal level. Neither antibodies against gamma-SNAP nor recombinant gamma-SNAP have any effect on ER-Golgi transport. These results clearly establish an essential role for alpha-SNAP but not gamma-SNAP in ER-Golgi transport. When the transport assay is performed with cytosol immunodepleted of alpha-SNAP, followed by incubation with cytosol immunodepleted of a COPII subunit, normal transport is achieved. In marked contrast, no transport is detected when the assay is first performed with cytosol depleted of the COPII subunit followed by alpha-SNAP-depleted cytosol, suggesting that alpha-SNAP is required after a step that requires COPII (the budding step). In combination with cytosol immunodepleted of Rab1, it is seen that alpha-SNAP is required after a Rab1-requiring step. It has been shown previously that EGTA blocks ER-Golgi transport at a step after vesicle docking but before fusion and we show here that alpha-SNAP acts before the step that is blocked by EGTA. Our results suggest that alpha-SNAP may be involved in the pre-docking or docking but not the fusion process.

A 29-kilodalton Golgi soluble N-ethylmaleimide-sensitive factor attachment protein receptor (Vti1-rp2) implicated in protein trafficking in the secretory pathway

Expressed sequence tags coding for a potential SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) were revealed during data base searches. The deduced amino acid sequence of the complete coding region predicts a 217-residue protein with a COOH-terminal hydrophobic membrane anchor. Affinity-purified antibodies raised against the cytoplasmic region of this protein specifically detect a 29-kilodalton integral membrane protein enriched in the Golgi membrane. Indirect immunofluorescence microscopy reveals that this protein is mainly associated with the Golgi apparatus. When detergent extracts of the Golgi membrane are incubated with immobilized glutathione S-transferase alpha soluble N-ethylmaleimide-sensitive factor attachment protein (GST-alpha-SNAP), this protein was specifically retained. This protein has been independently identified and termed Vti1-rp2, and it is homologous to Vti1p, a yeast Golgi SNARE. We further show that Vti1-rp2 can be qualitatively coimmunoprecipitated with Golgi syntaxin 5 and syntaxin 6, suggesting that Vti1-rp2 exists in at least two distinct Golgi SNARE complexes. In cells microinjected with antibodies against Vti1-rp2, transport of the envelope protein (G-protein) of vesicular stomatitis virus from the endoplasmic reticulum to the plasma membrane was specifically arrested at the Golgi apparatus, providing further evidence for functional importance of Vti1-rp2 in protein trafficking in the secretory pathway.

Syntaxin 11: a member of the syntaxin family without a carboxyl terminal transmembrane domain

We have cloned a novel syntaxin-like molecule, designated human syntaxin 11 (hsyn11). The open reading frame encodes a polypeptide of 287 amino acids with potential coiled-coil domains. hsyn11 has extensive homology to members of the syntaxin family, particularly syntaxin 1 and syntaxin 2. Unlike other members of the syntaxin family, however, hsyn11 has a short cysteinerich carboxyl-terminal tail but not a typical hydrophobic domain which may serve as a membrane anchor. Northern blot analysis revealed two transcripts of approximately 0.8 kb and approximately 1.7 kb in length that are particularly abundant in heart and placenta, although lower levels were also detectable in other tissues except in the brain. Consistent with the lack of a distinct membrane anchorage sequence in hsyn11, indirect immunofluorescence microscopy of transiently expressed N-terminally myc-tagged hsyn11 revealed a diffuse, cytoplasmic labeling.

Syntaxin 12, a member of the syntaxin family localized to the endosome

We have cloned a new member of the syntaxin family of proteins. The open reading frame encodes a polypeptide of 272 amino acids with potential coiled-coil domains and a C-terminal hydrophobic tail. Northern blot analysis showed that the transcript is fairly ubiquitous. A soluble recombinant form of the polypeptide without the hydrophobic region binds to alpha-SNAP (soluble N-ethylmaleimide-sensitive factor attachment protein) and syndet/SNAP-23 in vitro. Polyclonal antibody raised against the recombinant protein recognized a 39-kDa protein in the membrane fraction of cell lysates. Indirect immunofluorescence studies using the polyclonal antibody showed that the protein is localized to intracellular membrane structures. Selective permeabilization studies with digitonin and saponin indicate that the epitope(s) recognized by the antibody is expose to the cytoplasm, consistent with the predicted orientation characteristic of SNAP receptor molecules. Morphological alterations of the staining pattern of the protein with brefeldin A and wortmannin treatment indicate that the protein is localize to the endosome. The cDNA we have cloned apparently corresponded to three previously described expressed sequence tags named as syntaxins 12, 13, and 14, respectively. We therefore propose to retain the name syntaxin 12 for this protein.

Hsec22c: a homolog of yeast Sec22p and mammalian rsec22a and msec22b/ERS-24

We have cloned a new member of a family of mammalian proteins homologous to Sec22p, a v-SNARE in Saccharomyces cerevisiae required for transport between the endoplasmic reticulum (ER) and the Golgi apparatus. The open reading frame encodes a polypeptide of 250 amino acids which is homologous to, but obviously different from, the recently reported mammalian Sec22p homologs rat sec22a, mouse sec22b, and hamster ERS-24. Northern blot analysis revealed two transcripts of about 1 and 5 kb respectively which are ubiquitously expressed. myc-epitope tagged sec22c is localized to the ER. Overexpression of the myc-tagged protein resulted in an anomalous staining pattern of SNARE molecules participating in ER-Golgi transport such as syntaxin 5 and mammalian bet1, but not the endosomal SNARE syntaxin 7. The presence of multiple forms of sec22 protein in the mammalian early secretory pathway is in-line with task specification in a highly elaborate transport machinery.

Molecular cloning and localization of human syntaxin 16, a member of the syntaxin family of SNARE proteins

We have cloned a new member of the syntaxin family of proteins, designated human syntaxin 16 (hsyn16). The open reading frame encodes a polypeptide of 307 amino acids with potential coiled-coil domains and a carboxy-terminal hydrophobic tail, which is characteristic of other members of the syntaxin family. The encoded polypeptide bears sequence homology to known syntaxin molecules. Northern blot analysis revealed a single transcript that is fairly ubiquitous, being slightly more enriched in heart and pancreas. Indirect immunofluorescence localised myc-tagged hsyn16 (myc-hsyn16) to the Golgi apparatus, colocalizing well with lens culinaris agglutinin, an established Golgi marker, as well as with other Golgi SNAREs such as GS28 and syntaxin 5. Myc-hsyn16 is redistributed to the endoplasmic reticulum upon brefeldin A treatment, indicating that it is localised to the Golgi stack. The ubiquitous expression and Golgi localization of hsy16 suggest that it is involved in a vesicular transport step within the organelle.

Syntaxin 10: a member of the syntaxin family localized to the trans-Golgi network

We have cloned a new member of the syntaxin family of proteins, designated human syntaxin 10 (hsyn10). The open reading frame encodes a polypeptide of 249 amino acids with potential coiled-coil domains and a carboxy-terminal hydrophobic tail. hsyn10 is particularly homologous to the recently reported rat syntaxin 6 (about 60% identity). Northern blot analysis showed that the transcript is enriched in the heart, skeletal muscles and pancreas. Indirect immunofluorescence studies using polyclonal antibodies raised against recombinant protein showed that the protein is localized to intracellular membrane structures, with perinuclear staining patterns colocalising well with the Golgi SNARE GS28. Morphological alterations of the staining pattern of the protein with brefeldin A but not wortmannin treatment indicate that the protein is localize to the trans-Golgi network.

The mammalian protein (rbet1) homologous to yeast Bet1p is primarily associated with the pre-Golgi intermediate compartment and is involved in vesicular transport from the endoplasmic reticulum to the Golgi apparatus

Yeast Bet1p participates in vesicular transport from the endoplasmic reticulum to the Golgi apparatus and functions as a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) associated with ER-derived vesicles. A mammalian protein (rbet1) homologous to Bet1p was recently identified, and it was concluded that rbet1 is associated with the Golgi apparatus based on the subcellular localization of transiently expressed epitope-tagged rbet1. In the present study using rabbit antibodies raised against the cytoplasmic domain of rbet1, we found that the majority of rbet1 is not associated with the Golgi apparatus as marked by the Golgi mannosidase II in normal rat kidney cells. Rather, rbet1 is predominantly associated with vesicular spotty structures that concentrate in the peri-Golgi region but are also present throughout the cytoplasm. These structures colocalize with the KDEL receptor and ERGIC-53, which are known to be enriched in the intermediate compartment. When the Golgi apparatus is fragmented by nocodazole treatment, a significant portion of rbet1 is not colocalized with structures marked by Golgi mannosidase II or the KDEL receptor. Association of rbet1 in cytoplasmic spotty structures is apparently not altered by preincubation of cells at 15 degrees C. However, upon warming up from 15 to 37 degrees C, rbet1 concentrates into the peri-Golgi region. Furthermore, rbet1 colocalizes with vesicular stomatitis virus G-protein en route from the ER to the Golgi. Antibodies against rbet1 inhibit in vitro transport of G-protein from the ER to the Golgi apparatus in a dose-dependent manner. This inhibition can be neutralized by preincubation of antibodies with recombinant rbet1. EGTA is known to inhibit ER-Golgi transport at a stage after vesicle docking but before the actual fusion event. Antibodies against rbet1 inhibit ER-Golgi transport only when they are added before the EGTA-sensitive stage. These results suggest that rbet1 may be involved in the docking process of ER-derived vesicles with the cis-Golgi membrane.

Endoplasmic reticulum retention mediated by the transmembrane domain of type II membrane proteins Sec12p and glucosidase 1

The yeast Sec12p, a type II protein localized to the yeast endoplasmic reticulum (ER), is similarly localized to the ER when expressed in mammalian cells. Replacing the transmembrane domain of the plasma membrane molecule dipeptidyl peptidase IV (D4) with that of Sec12p or the ER-localized enzyme glucosidase 1 resulted in the ER retention of the chimeric molecules, as assessed by immunocytochemical localization and the persistence of pulse-labeled proteins in the endoglycosidase H-sensitive form. Retention is not due to gross misfolding as these chimeras remained enzymatically active. Density gradient analysis revealed that the ER-localized chimeric molecules form high molecular weight oligomers quickly after synthesis. The type II transmembrane domain of ER proteins could therefore mediate retention in the ER.

The mammalian homolog of yeast Sec13p is enriched in the intermediate compartment and is essential for protein transport from the endoplasmic reticulum to the Golgi apparatus

The role of COPII components in endoplasmic reticulum (ER)-Golgi transport, first identified in the yeast Saccharomyces cerevisiae, has yet to be fully characterized in higher eukaryotes. A human cDNA whose predicted amino acid sequence showed 70% similarity to the yeast Sec13p has previously been cloned. Antibodies raised against the human SEC13 protein (mSEC13) recognized a cellular protein of 35 kDa in both the soluble and membrane fractions. Like the yeast Sec13p, mSEC13 exist in the cytosol in both monomeric and higher-molecular-weight forms. Immunofluorescence microscopy localized mSEC13 to the characteristic spotty ER-Golgi intermediate compartment (ERGIC) in cells of all species examined, where it colocalized well with the KDEL receptor, an ERGIC marker, at 15 degrees C. Immunoelectron microscopy also localized mSEC13 to membrane structures close to the Golgi apparatus. mSEC13 is essential for ER-to-Golgi transport, since both the His6-tagged mSEC13 recombinant protein and the affinity-purified mSEC13 antibody inhibited the transport of restrictive temperature-arrested vesicular stomatitis virus G protein from the ER to the Golgi apparatus in a semi-intact cell assay. Moreover, cytosol immunodepleted of mSEC13 could no longer support ER-Golgi transport. Transport could be restored in a dose-dependent manner by a cytosol fraction enriched in the high-molecular-weight mSEC13 complex but not by a fraction enriched in either monomeric mSEC13 or recombinant mSEC13. As a putative component of the mammalian COPII complex, mSEC13 showed partially overlapping but mostly different properties in terms of localization, membrane recruitment, and dynamics compared to that of beta-COP, a component of the COPI complex.

Cytotoxicity of KDEL-terminated ricin toxins correlates with distribution of the KDEL receptor in the Golgi

DNAs encoding ricin toxin A chain (RTA), with or without a C-terminal endoplasmic reticulum retention signal KDEL, were subcloned into pGEX2T bacterial expression plasmid. After transformation of JM105 E. coli cells and induction with isopropylthio-beta-galactoside (IPTG), fusion proteins were bound to an immobilized glutathione matrix and recombinant ricin A chains released with thrombin. Both recombinant wild-type RTA and RTA with KDEL had immunological reactivity and catalytic activity indistinguishable from plant RTA. The bacterial RTA products reassociated with plant ricin B chain (RTB) similarly to plant RTA. Cell cytotoxicities were measured on seven cell lines for each A-chain and heterodimer. Although KDEL sequences enhanced cytotoxicity in most cases, significant variability was observed. In each case, addition of KDEL enhanced A-chain cytotoxicity more than holotoxin cytotoxicity. Three cell lines showed reduced KDEL enhancement of both RTA and ricin cytotoxicity. The concentration of KDEL receptor was examined on each cell line by immunofluorescence microscopy with an antireceptor monoclonal antibody. Differences in sensitivity to KDEL-containing toxins correlated with altered distribution of KDEL receptor between endoplasmic reticulum (ER) and Golgi compartments.