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1.
World J Gastrointest Surg ; 15(8): 1751-1760, 2023 Aug 27.
Article in English | MEDLINE | ID: mdl-37701694

ABSTRACT

BACKGROUND: Early gastric cancer (EGC) is typically treated with endoscopic submucosal dissection (ESD). However, recurrence may occur after ESD, requiring surveillance. AIM: To examine the knowledge, attitude, and practice (KAP) of EGC survivors following ESD regarding gastric cancer recurrence. METHODS: This cross-sectional study was conducted between June 1, 2022 and October 1, 2022 in Zhejiang, China. A total of 400 EGC survivors who underwent ESD at the Affiliated Jinhua Hospital, Zhejiang University School of Medicine participated in this study. A self-administered questionnaire was developed to assess KAP monitoring gastric cancer after ESD. RESULTS: The average scores for KAP were 3.34, 23.76, and 5.75 out of 5, 30, and 11, respectively. Pearson correlation analysis revealed positive and significant correlations between knowledge and attitude, knowledge and practice, and attitude and practice (r = 0.405, 0.511, and 0.458, respectively; all P < 0.001). Multivariate logistic regression analysis showed that knowledge, attitude, 13-24 mo since the last ESD (vs ≤ 12 mo since the last ESD), and ≥ 25 mo since the last ESD (vs ≤ 12 mo since the last ESD) were independent predictors of proactive practice (odds ratio = 1.916, 1.253, 3.296, and 5.768, respectively, all P < 0.0001). CONCLUSION: EGC survivors showed inadequate knowledge, positive attitude, and poor practices in monitoring recurrences after ESD. Adequate knowledge, positive attitude, and a longer time since the last ESD were associated with practice.

2.
World J Clin Cases ; 8(4): 798-805, 2020 Feb 26.
Article in English | MEDLINE | ID: mdl-32149063

ABSTRACT

BACKGROUND: Mesenteric phlebosclerosis (MP) is a rare disease of the colon. The clinical manifestations of this disease are nonspecific and it may easily be misdiagnosed. We report a case of MP with amyloidosis in the colonic vessel walls in a patient with hypertension who had been consuming Chinese medicinal liquor for 10 years. We also review the relevant literature and summarize the characteristics of MP in patients in mainland China. CASE SUMMARY: A 64-year-old man was referred to our department from his primary hospital because of abdominal pain, diarrhea, and fever for almost 10 d. Computed tomography showed colon wall thickening, with threadlike calcifications in the mesenteric vein in the transverse colon. Colonoscopy revealed purple-blue mucosa with multiple ulcers in the ascending and transverse colon. Biopsy showed thickening and calcification of the vein walls, perivascular and mucosal collagen degeneration, and amyloidosis. The patient had been consuming Chinese medicinal liquor, mainly that made from gardenia fruit, for 10 years. Based on these results, a diagnosis of MP with amyloidosis was made. After conservative treatment, the patient's discomfort subsided and he was followed closely. The use of Chinese herbal medicine was suspected to play a role in the pathogenesis of MP. CONCLUSION: The clinical manifestations of MP are nonspecific. Recognition of its typical imaging findings, including multiple calcifications on computed tomography and purple-blue mucosal discoloration on colonoscopy, is vital.

3.
BMC Infect Dis ; 19(1): 637, 2019 Jul 17.
Article in English | MEDLINE | ID: mdl-31315559

ABSTRACT

BACKGROUND: Rat bite fever (RBF), a severe infectious disease, can result from transmission of the pathogen Streptobacillus moniliformis (S. moniliformis) by rat bite. RBF diagnosis can be overlooked. CASE PRESENTATION: We present a case of RBF in a Chinese patient who was infected with S. moniliformis in mainland China. Meta-next generation sequencing (mNGS) was used to identify potential pathogens and detected S. moniliformis genome sequences in the pustular sample in less than 72 h. Then the diagnosis was validated by polymerase chain reaction analysis. Despite having severe RBF with complications, this 54-year-old male patient was successfully cured with penicillin as a result of timely pathogen-based diagnosis. CONCLUSIONS: Physicians should inquire about recent rat exposure and consider the possibility of RBF when a patient develops unexplained fever and rashes. mNGS is a new diagnostic technology and may identify RBF pathogens even when blood culture results are negative.


Subject(s)
Rat-Bite Fever/etiology , Streptobacillus/pathogenicity , Animals , China , Exanthema/microbiology , High-Throughput Nucleotide Sequencing , Humans , Male , Penicillins/therapeutic use , Rat-Bite Fever/drug therapy , Rat-Bite Fever/microbiology , Rats , Streptobacillus/genetics
4.
Clin Nutr ; 38(6): 2552-2557, 2019 12.
Article in English | MEDLINE | ID: mdl-30573353

ABSTRACT

OBJECTIVE: Nonalcoholic fatty liver disease (NAFLD) is the most predominant chronic liver disease worldwide. Effect of coffee on NAFLD risk and its potential dose-response patterns were explored in the study. DESIGN: PubMed, Web of Science, MEDLINE, Cochrane and Embase were searched up to 10 April 2018. We performed pair-wise meta-analysis of <1 cup per day vs. 1-2 cups per days or >2 cups per day to pool the relative risks (RRs) and corresponding 95% confidence intervals (CIs). And dose-response analysis was used to estimate relationship of NAFLD occurrence with coffee intake. RESULTS: Seven articles were included with 4825 cases and 49,616 non-cases. Compared with <1 cup, 1-2 cups or >2 cups of coffee consumption per day were not significantly associated with NAFLD occurrence, and RR were 0.97 (95% CI: 0.85-1.11) and 0.88 (95%CI: 0.72-1.06). However, the summary RR of the highest versus lowest coffee consumption was 0.94 (95% CI: 0.92-0.97). Dose-response meta-analysis presented a non-linearity curve relationship of coffee and NAFLD occurrence while coffee consumption >3 cups per day reduced NAFLD significantly. CONCLUSION: Coffee intake level more than 3 cups was observed lower risk of NAFLD than <2 cups per day. Although the risk of NAFLD was inversely associated with coffee consumption, while relevance may not be very close and more observational studies would be needed to verify the relationship of coffee and NAFLD.


Subject(s)
Coffee , Diet/statistics & numerical data , Non-alcoholic Fatty Liver Disease/epidemiology , Adult , Aged , Female , Humans , Male , Middle Aged , Risk Factors , Young Adult
5.
Cell Physiol Biochem ; 51(5): 2111-2122, 2018.
Article in English | MEDLINE | ID: mdl-30522100

ABSTRACT

BACKGROUND/AIMS: Sestrin 2 is associated with the pathophysiology of several diseases. The aim of this study was to investigate the effects and potential mechanisms of Sestrin 2 in rat hepatic stellate cells (HSCs) during liver fibrogenesis. METHODS: In this study, Sestrin 2 protein expression was detected in rat HSC-T6 cells challenged with transforming growth factor-ß (TGF-ß) and in mice treated with carbon tetrachloride (CCl4), a well-known model of hepatic fibrosis. Next, HSC-T6 cells and fibrotic mice were transfected with lentivirus. The mRNA expression levels of markers of liver fibrosis [alpha-smooth muscle actin (α-SMA) and collagen 1A1 (Col1A1)] were analyzed by quantitative reverse transcription-polymerase chain reaction (RT-PCR). Cell death and proliferation were evaluated by the MTT assay, and biochemical markers of liver damage in serum [alanine transaminase (ALT) and aspartate transaminase (AST)] were also measured using a biochemical analyzer. Histopathological examination was used to evaluate the degree of liver fibrosis, and protein expression [phospho-adenosine monophosphate-activated protein kinase (p-AMPK), AMPK, phospho-mammalian target of rapamycin (p-mTOR), and mTOR] was determined by western blotting. RESULTS: We found that Sestrin 2 was elevated in both the HSC-T6 cell and hepatic fibrosis models. In vitro, overexpression of Sestrin 2 attenuated the mRNA levels of α-SMA and Col1A1, suppressed α-SMA protein expression, and modulated HSC-T6 cell proliferation. In vivo, overexpression of Sestrin 2 reduced the ALT and AST levels as well as the α-SMA and Col1A1 protein expression in the CCl4 model of liver fibrosis. Moreover, the degree of liver fibrosis was ameliorated. Interestingly, overexpression of Sestrin 2 increased p-AMPK but decreased p-mTOR protein expression. CONCLUSION: Our findings indicate that Sestrin 2 may attenuate the activation of HSCs and ameliorate liver fibrosis, most likely via upregulation of AMPK phosphorylation and suppression of the mTOR signaling pathway.


Subject(s)
AMP-Activated Protein Kinases/metabolism , Hepatic Stellate Cells/pathology , Liver Cirrhosis/pathology , Nuclear Proteins/metabolism , Signal Transduction , TOR Serine-Threonine Kinases/metabolism , Animals , Cell Line , Hepatic Stellate Cells/metabolism , Liver/metabolism , Liver/pathology , Liver Cirrhosis/metabolism , Male , Mice, Inbred C57BL , Peroxidases , Phosphorylation , Rats
6.
Gastroenterol Res Pract ; 2018: 8620682, 2018.
Article in English | MEDLINE | ID: mdl-30254671

ABSTRACT

BACKGROUND: Type 2 diabetes mellitus (T2DM) patients are involved closely with cancer. This work aims to conduct a systematic review and network meta-analysis (NMA) to examine the effect of different types of statins on cancer incidence in patients with T2DM. METHODS: We systematically searched the Cochrane Library, PubMed, Embase, and Wanfang databases from January 1999 to March 2017. We performed a pairwise meta-analysis to estimate the pooled ratios (ORs) and 95% confidence intervals (CIs). A NMA was performed to compare different types of statins. RESULTS: Seven publications were included. In pairwise meta-analysis, the incidence of cancer in T2DM patients was reduced when simvastatin, atorvastatin, pravastatin, fluvastatin, lovastatin, rosuvastatin, and pitavastatin were used. In the result of NMA, the usage of simvastatin (RR 0.30 and 95% CI 0.16-0.56), atorvastatin (RR 0.29 and 95% CI 0.09-0.88), pravastatin (RR 0.34 and 95% CI 0.12-0.93), fluvastatin (RR 0.27 and 95% CI 0.09-0.83), rosuvastatin (RR 0.22 and 95% CI 0.10-0.49), and pitavastatin (RR 0.33 and 95% CI 0.20-0.57) was superior to the nonstatin groups. When compared with six other statins, rosuvastatin appeared to be the best one. CONCLUSIONS: Different statins can reduce the risk of cancer in patients with T2DM. Our analyses suggest that rosuvastatin may be more effective than others.

7.
Curr Med Sci ; 38(3): 467-472, 2018 Jun.
Article in English | MEDLINE | ID: mdl-30074214

ABSTRACT

Epithelial-to-mesenchymal transition (EMT) plays a critical role in cancer metastasis, and is relevant to the inflammatory microenvironment. Lipopolysaccharide (LPS), a cell wall constituent of gram-negative bacteria, has been reported to induce EMT of cancer cells through TLR4 signal. We previously reported that LPS promoted metastasis of mesenchymallike breast cancer cells with high expression of cyclin D1b. However, the role of cyclin D1b in LPS-induced EMT has not been fully elucidated. In the present study, we described that cyclin D1b augmented EMT induced by LPS in MCF-7 breast cancer cells. Cyclin D1b markedly amplified integrin αvß3 expression, which was further up-regulated under LPS stimulation. Our results showed ectopic expression of cyclin D1b promoted invasiveness of epithelial-like MCF-7 cells under LPS stimulation. Additionally, LPS-induced metastasis and EMT in MCF-7-D1b cells might depend on αvß3 expression. Further exploration indicated that cyclin D1b cooperated with HoxD3, a transcription factor promoting αvß3 expression, to promote LPSinduced EMT. Knockout of HoxD3 repressed LPS-induced EMT and αvß3 over-expression in MCF-7 cells with high expression of cyclin D1b. Specifically, all these effects were in a cyclin Dla independent manner. Taken all together, LPS up-regulated integrin αvß3 expression in MCF-7 cells with high expression of cyclin D1b and induced EMT in breast cancer cells, which highlights that cyclin D1b may act as an endogenous pathway participating in exogenous signal inducing EMT in breast cancer cells.


Subject(s)
Alternative Splicing/genetics , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Cyclin D1/genetics , Epithelial-Mesenchymal Transition/genetics , Integrin alphaVbeta3/metabolism , Lipopolysaccharides/pharmacology , Alternative Splicing/drug effects , Cell Adhesion/drug effects , Cell Movement/drug effects , Cyclin D1/metabolism , Epithelial-Mesenchymal Transition/drug effects , Female , Fibrinogen/pharmacology , Homeodomain Proteins/metabolism , Humans , MCF-7 Cells , Neoplasm Invasiveness , Neoplasm Metastasis , Transcription Factors , Transfection , Up-Regulation/drug effects
8.
Exp Ther Med ; 15(6): 4838-4850, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29904396

ABSTRACT

The most suitable treatment regimen for autoimmune hepatitis (AIH) in adults remains unknown and requires further investigation. The current study therefore aimed to integrate evidence to provide hierarchies of the comparative efficacies of treatments measured by clinical and biochemical remission. A Bayesian-framework network meta-analysis of randomized controlled trials (RCTs) was preformed to compare eight treatments for AIH. Eligible RCTs were identified by searching Embase, Pubmed and the Cochrane Library for publications between 1966 and April 2017. All outcomes were independently extracted from the included studies by two authors. A total of six RCTs were subsequently included in the current study. The network of comparisons on remission indicated that patients treated with prednisone (pred) experienced significantly increased rates of remission compared with those treated with azathioprine [AZA; odds ratio (OR), 0.21; 95% confidence interval (CI), 0.06-0.71] and budesonide (bude) + AZA significantly increased remission compared with placebo treatment (OR, 36.66; 95% CI, 1.40-962.49) or AZA (OR, 10.30; 95% CI, 1.50-70.70). Based on the cumulative ranking probabilities, bude + AZA (89.4) was ranked first, pred (69.1) was ranked second, pred + AZA (63.2) was ranked third and placebo (7.8) treatment was ranked last. Bude + AZA may be the most appropriate candidate for the treatment of non-cirrhotic patients. However, bude + AZA as frontline therapy for AIH requires more large-scale studies with a longer duration of follow-up histology and a focus on dose-response. Additionally, development of other prospective treatments, which may be used as alternative therapy or first line therapy, and their subsequent evaluation in clinical RCTs is required.

9.
Mol Plant Pathol ; 19(9): 2149-2161, 2018 09.
Article in English | MEDLINE | ID: mdl-29660235

ABSTRACT

Pathogen-host interaction is a complicated process; pathogens mainly infect host plants to acquire nutrients, especially sugars. Rhizoctonia solani, the causative agent of sheath blight disease, is a major pathogen of rice. However, it is not known how this pathogen obtains sugar from rice plants. In this study, we found that the rice sugar transporter OsSWEET11 is involved in the pathogenesis of sheath blight disease. Quantitative real-time polymerase chain reaction (qRT-PCR) and ß-d-glucuronidase expression analyses showed that R. solani infection significantly enhanced OsSWEET11 expression in leaves amongst the clade III SWEET members. The analyses of transgenic plants revealed that Ossweet11 mutants were less susceptible, whereas plants overexpressing OsSWEET11 were more susceptible, to sheath blight compared with wild-type controls, but the yield of OsSWEET11 mutants and overexpressors was reduced. SWEETs become active on oligomerization. Split-ubiquitin yeast two-hybrid, bimolecular fluorescence complementation and co-immunoprecipitation assays showed that mutated OsSWEET11 interacted with normal OsSWEET11. In addition, expression of conserved residue mutated AtSWEET1 inhibited normal AtSWEET1 activity. To analyse whether inhibition of OsSWEET11 function in mesophyll cells is related to defence against this disease, mutated OsSWEET11 was expressed under the control of the Rubisco promoter, which is specific for green tissues. The resistance of transgenic plants to sheath blight disease, but not other disease, was improved, whereas yield production was not obviously affected. Overall, these results suggest that R. solani might acquire sugar from rice leaves by the activation of OsSWEET11 expression. The plants can be protected from infection by manipulation of the expression of OsSWEET11 without affecting the crop yield.


Subject(s)
Mesophyll Cells/microbiology , Oryza/microbiology , Plant Diseases/microbiology , Plants, Genetically Modified/microbiology , Disease Resistance/genetics , Gene Expression Regulation, Plant/genetics , Mesophyll Cells/metabolism , Plant Diseases/genetics , Plants, Genetically Modified/genetics , Promoter Regions, Genetic/genetics , Real-Time Polymerase Chain Reaction
10.
Oncotarget ; 8(45): 78466-78479, 2017 Oct 03.
Article in English | MEDLINE | ID: mdl-29108242

ABSTRACT

The concept of cancer stem cells has been proposed in various malignancies including colorectal cancer. Recent studies show direct evidence for quiescence slow-cycling cells playing a role in cancer stem cells. There exists an urgent need to isolate and better characterize these slow-cycling cells. In this study, we developed a new model to enrich slow-cycling tumor cells using cell-cycle inducer combined with cell cycle-dependent chemotherapy in vitro and in vivo. Our results show that Short-term exposure of colorectal cancer cells to chemotherapy combined with cell-cycle inducer enriches for a cell-cycle quiescent tumor cell population. Specifically, these slow-cycling tumor cells exhibit increased chemotherapy resistance in vitro and tumorigenicity in vivo. Notably, these cells are stem-cell like and participate in metastatic dormancy. Further exploration indicates that slow-cycling colorectal cancer cells in our model are less sensitive to cytokine-induced-killer cell mediated cytotoxic killing in vivo and in vitro. Collectively, our cell cycle inducer combined chemotherapy exposure model enriches for a slow-cycling, dormant, chemo-resistant tumor cell sub-population that are resistant to cytokine induced killer cell based immunotherapy. Studying unique signaling pathways in dormant tumor cells enriched by cell cycle inducer combined chemotherapy treatment is expected to identify novel therapeutic targets for preventing tumor recurrence.

11.
Mol Med Rep ; 16(4): 4327-4333, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28731181

ABSTRACT

The aim of the present study was to investigate the role of microRNA (miR)­21 in regulating collagen I and Smad7 expression in activated rat hepatic stellate cells (HSCs). Rat HSCs were isolated by single­step density gradient centrifugation with Nycodenz. Cellular content of miR­21, SMAD7, α­smooth muscle actin (α­SMA), collagen type I alpha 1 (COLLA1) and COLL alpha 2 (A2) mRNA was examined by reverse transcription­quantitative polymerase chain reaction (RT­qPCR), and cellular content of Smad7 and α­SMA protein was detected by western blotting. Binding of miR­21 to the 3'­untranslated region (UTR) of Smad7 was verified by dual­luciferase assay. The authors observed that, in activated HSCs, expression of miR­21 was significantly increased in a time­dependent manner, while expression of Smad7 mRNA and protein was significantly reduced. In addition, miR­21 mimics significantly enhanced cellular α­SMA mRNA and protein content, while miR­21 inhibitor significantly reduced α­SMA mRNA and protein levels. Similarly, cellular content of COLLA1 and COLLA2 mRNA was significantly elevated by miR­21 mimics, but reduced by miR­21 inhibitor, in activated HSCs. Moreover, cellular content of Smad7 mRNA and protein was significantly reduced by miR­21 mimics, but significantly increased by miR­21 inhibitor. Furthermore, miR­21 mimics activated firefly luciferase in HEK293 cells transfected with the wild type 3'­UTR of Smad7. miR­21 regulates expression of α­SMA and collagen I in activated rat HSCs by directly targeting Smad7.


Subject(s)
Actins/metabolism , Collagen Type I/metabolism , Hepatic Stellate Cells/metabolism , MicroRNAs/metabolism , Signal Transduction , Smad7 Protein/metabolism , Animals , Collagen Type I, alpha 1 Chain , HEK293 Cells , Hepatic Stellate Cells/drug effects , Humans , Male , MicroRNAs/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats, Sprague-Dawley , Signal Transduction/drug effects , Smad7 Protein/genetics , Transforming Growth Factor beta/pharmacology , Up-Regulation/drug effects
12.
Medicine (Baltimore) ; 96(14): e6465, 2017 Apr.
Article in English | MEDLINE | ID: mdl-28383410

ABSTRACT

There is currently a lack of reliable, reproducible, and easily applied methods for assessing changes in liver histology in patients in the gray zone phase of chronic hepatitis B (CHB). Therefore, we aimed to develop a novel predictive scoring system to detect significant liver histological changes in these patients.A total of 388 patients in the gray zone phase of CHB who underwent liver biopsy were divided into a training group and a validation group, and their clinical and routinely available laboratory parameters were analyzed using univariate analysis, Spearman correlation analysis, and logistic modeling. A novel scoring system, termed the Significant Histological Model (SHM), was constructed using logistic modeling. The diagnostic accuracy of our novel scoring system was evaluated by the receiving operating characteristic (ROC) method, sensitivity, specificity, and positive and negative predictive values (NPVs).We established the novel SHM scoring system using serum aspartate transaminase (AST), platelet counts (PLTs), albumin (ALB), and hepatitis B virus (HBV) DNA (log10 IU/mL) levels. The area under the ROC curve of the SHM scoring system was 0.763 in the training group and 0.791 in the validation group. For patients with a score of -1.0 or less and no significant histological changes, the sensitivity was 78.9%, specificity was 51.5%, positive predictive value (PPV) was 46.4%, and NPV was 82.0%. In the validation set, the sensitivity, specificity, PPV, and NPV were 80.0%, 66.6%, 56.3%, and 86.2%, respectively.This novel scoring system using AST, PLT, ALB, and HBV DNA (log10 IU/mL) levels identifies patients in the gray zone phase of CHB with and without histological changes with a high degree of accuracy. Here, we provide the experimental basis for the initiation of clinical antiviral treatment without the need for liver biopsy.


Subject(s)
Biomarkers/blood , Hepatitis B, Chronic/blood , Liver/pathology , Models, Biological , Adult , Female , Hepatitis B, Chronic/pathology , Humans , Male , Middle Aged , Retrospective Studies
13.
Minerva Med ; 108(3): 268-276, 2017 Jun.
Article in English | MEDLINE | ID: mdl-27973467

ABSTRACT

INTRODUCTION: The aim of this study was to evaluate the correlation of High-mobility group box 1 (HMGB1) expression in the serum with chronic hepatitis B (CHB) related liver fibrosis, severe hepatitis B and acute-on-chronic liver failure (ACLF). EVIDENCE ACQUISITION: We made a literature search in PubMed, Embase, Web of Science, Medline, Google Scholar, China National Knowledge Infrastructure, WanFang with no language restriction. Pooled data were analyzed and mean difference with corresponding 95% confidence intervals were calculated. EVIDENCE SYNTHESIS: A total of 16 relevant studies were identified. HMGB1 serum levels were higher in severe hepatitis B or ACLF patients than those in CHB patients. Pooled mean differences of HMGB1 in severe hepatitis B and ACLF patients compared with CHB patients were 4.32 (95% CI: 0.34-8.29, Z=2.13, I2=59%, P=0.03) and 15.96 (95% CI: -0.37-32.28, Z=1.92, P=0.06). Four studies showed there was a different HMGB1 expression in mild, moderate and severe CHB patients (P values were <0.05, <0.05, <0.05 and <0.01, respectively). Pooled mean difference of HMGB1 in low liver fibrosis patients compared with high liver fibrosis was -125.38 (95% CI: -539.44-288.68, Z=0.59, I2=98%, P=0.55). CONCLUSIONS: The results suggested that HMGB1 levels in the serum were statistically higher in severe hepatitis B and ACLF patients. Therefore, HMGB1 may be a useful therapeutic target for severe hepatitis B and ACLF diagnosis.


Subject(s)
Acute-On-Chronic Liver Failure/blood , HMGB1 Protein/blood , Hepatitis B, Chronic/blood , Liver Cirrhosis/blood , Hepatitis B, Chronic/complications , Humans , Liver Cirrhosis/etiology , Severity of Illness Index
16.
FASEB J ; 30(10): 3644-3654, 2016 10.
Article in English | MEDLINE | ID: mdl-27411857

ABSTRACT

SWEETs represent a new class of sugar transporters first described in plants, animals, and humans and later in prokaryotes. Plant SWEETs play key roles in phloem loading, seed filling, and nectar secretion, whereas the role of archaeal, bacterial, and animal transporters remains elusive. Structural analyses show that eukaryotic SWEETs are composed of 2 triple-helix bundles (THBs) fused via an inversion linker helix, whereas prokaryotic SemiSWEETs contain only a single THB and require homodimerization to form transport pores. This study indicates that SWEETs retained sugar transport activity in all kingdoms of life, and that SemiSWEETs are likely their ancestral units. Fusion of oligomeric subunits into single polypeptides during evolution of eukaryotes is commonly found for transporters. Phylogenetic analyses indicate that THBs of eukaryotic SWEETs may not have evolved by tandem duplication of an open reading frame, but rather originated by fusion between an archaeal and a bacterial SemiSWEET, which potentially explains the asymmetry of eukaryotic SWEETs. Moreover, despite the ancient ancestry, SWEETs had not been identified in fungi or oomycetes. Here, we report the identification of SWEETs in oomycetes as well as SWEETs and a potential SemiSWEET in primitive fungi. BdSWEET1 and BdSWEET2 from Batrachochytrium dendrobatidis, a nonhyphal zoosporic fungus that causes global decline in amphibians, showed glucose and fructose transport activities.-Hu, Y.-B., Sosso, D., Qu, X.-Q., Chen, L.-Q., Ma, L., Chermak, D., Zhang, D.-C., Frommer, W. B. Phylogenetic evidence for a fusion of archaeal and bacterial SemiSWEETs to form eukaryotic SWEETs and identification of SWEET hexose transporters in the amphibian chytrid pathogen Batrachochytrium dendrobatidis.


Subject(s)
Chytridiomycota/pathogenicity , Eukaryota/metabolism , Membrane Transport Proteins/metabolism , Monosaccharide Transport Proteins/metabolism , Animals , Biological Transport , Chytridiomycota/isolation & purification , Structure-Activity Relationship
17.
Proc Natl Acad Sci U S A ; 110(39): E3685-94, 2013 Sep 24.
Article in English | MEDLINE | ID: mdl-24027245

ABSTRACT

Eukaryotic sugar transporters of the MFS and SWEET superfamilies consist of 12 and 7 α-helical transmembrane domains (TMs), respectively. Structural analyses indicate that MFS transporters evolved from a series of tandem duplications of an ancestral 3-TM unit. SWEETs are heptahelical proteins carrying a tandem repeat of 3-TM separated by a single TM. Here, we show that prokaryotes have ancestral SWEET homologs with only 3-TM and that the Bradyrhizobium japonicum SemiSWEET1, like Arabidopsis SWEET11, mediates sucrose transport. Eukaryotic SWEETs most likely evolved by internal duplication of the 3-TM, suggesting that SemiSWEETs form oligomers to create a functional pore. However, it remains elusive whether the 7-TM SWEETs are the functional unit or require oligomerization to form a pore sufficiently large to allow for sucrose passage. Split ubiquitin yeast two-hybrid and split GFP assays indicate that Arabidopsis SWEETs homo- and heterooligomerize. We examined mutant SWEET variants for negative dominance to test if oligomerization is necessary for function. Mutation of the conserved Y57 or G58 in SWEET1 led to loss of activity. Coexpression of the defective mutants with functional A. thaliana SWEET1 inhibited glucose transport, indicating that homooligomerization is necessary for function. Collectively, these data imply that the basic unit of SWEETs, similar to MFS sugar transporters, is a 3-TM unit and that a functional transporter contains at least four such domains. We hypothesize that the functional unit of the SWEET family of transporters possesses a structure resembling the 12-TM MFS structure, however, with a parallel orientation of the 3-TM unit.


Subject(s)
Bacterial Proteins/metabolism , Carbohydrate Metabolism , Membrane Transport Proteins/metabolism , Multigene Family , Plant Proteins/metabolism , Protein Multimerization , Sucrose/metabolism , Amino Acids/metabolism , Arabidopsis/metabolism , Bacterial Proteins/chemistry , Biological Transport , Bradyrhizobium/metabolism , Genetic Complementation Test , Glucose/metabolism , Green Fluorescent Proteins/metabolism , Membrane Transport Proteins/chemistry , Models, Biological , Phylogeny , Plant Proteins/chemistry , Protein Structure, Secondary , Saccharomyces cerevisiae/metabolism , Signal Transduction , Structure-Activity Relationship
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