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Ge R, Liu L, Dai W, Zhang W, Yang Y, Wang H, Shi Q, Guo S, Yi X, Wang G, Gao T, Luan Q, Li C. 652 XPA promotes autophagy to facilitate cisplatin resistance in melanoma cells through the activation of PARP1. J Invest Dermatol 2016. [DOI: 10.1016/j.jid.2016.02.693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Zheng X, Liu L, Dai W, Wang K, Chen X, Zhao L, Huang Z, Hou J. [Establishment of a diet-induced obesity model in zebrafish larvae]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2016; 36:20-25. [PMID: 26806733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To establish a diet-induced obesity model in zebrafish larvae. METHODS At 7 days post-fertilization (dpf), 200 zebrafish larvae with normal development were randomly allocated to two groups with the feeding quantity of 30 mg per day (normal feeding group) or 180 mg per day (overfed group) for 20 days. The weight, length, BMI, triglyceride (TG) and total cholesterol (TCH) of each group were measured. Whole-mount Oil Red O staining, frozen Oil Red O staining and hematoxylin-eosin (HE) staining were used to estimate the rate of hepatic steatosis and liver histology of the zebrafish. The dynamic change of hepatic lipid droplets and distribution of adipose tissue were observed with Nile Red staining in overfed zebrafish in vivo. RESULTS The weight, length, BMI and TG of overfed zebrafish were significantly increased compared with those in normal feeding group. Whole-mount Oil Red O staining showed that the percent of hepatic steatosis in overfed group (89.4%) was markedly higher than that in normal feeding group (20.7%). Macrovesicular steatosis was observed in the liver of the overfed larvae. Nile Red staining visualized hepatic lipid droplets and the distribution of larval adipose tissue, which increased with feeding time in the overfed zebrafish. Starving larvae showed depletion of fat and hepatic lipid, and adipose tissue was induced after refeeding. CONCLUSIONS We successfully established an diet-induced obesity model in zebrafish larva, in which Nile Red staining allows in vivo observation of the adipocytes and hepatic lipid droplets.
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Yao W, Dai W, Jiang L, Lay EYA, Zhong Z, Ritchie RO, Li X, Ke H, Lane NE. Sclerostin-antibody treatment of glucocorticoid-induced osteoporosis maintained bone mass and strength. Osteoporos Int 2016; 27:283-294. [PMID: 26384674 PMCID: PMC4958115 DOI: 10.1007/s00198-015-3308-6] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 08/25/2015] [Indexed: 12/18/2022]
Abstract
UNLABELLED This study was to determine if antibody against sclerostin (Scl-Ab) could prevent glucocorticoid (GC)-induced osteoporosis in mice. We found that Scl-Ab prevented GC-induced reduction in bone mass and bone strength and that the anabolic effects of Scl-Ab might be partially achieved through the preservation of osteoblast activity through autophagy. INTRODUCTION Glucocorticoids (GCs) inhibit bone formation by altering osteoblast and osteocyte cell activity and lifespan. A monoclonal antibody against sclerostin, Scl-Ab, increased bone mass in both preclinical animal and clinical studies in subjects with low bone mass. The objectives of this study were to determine if treatment with the Scl-Ab could prevent loss of bone mass and strength in a mouse model of GC excess and to elucidate if Scl-Ab modulated bone cell activity through autophagy. METHODS We generated reporter mice that globally expressed dsRed fused to LC3, a protein marker for autophagosomes, and evaluated the dose-dependent effects of GCs (0, 0.8, 2.8, and 4 mg/kg/day) and Scl-Ab on autophagic osteoblasts, bone mass, and bone strength. RESULTS GC treatment at 2.8 and 4 mg/kg/day of methylprednisolone significantly lowered trabecular bone volume (Tb-BV/TV) at the lumbar vertebrae and distal femurs, cortical bone mass at the mid-shaft femur (FS), and cortical bone strength compared to placebo (PL). In mice treated with GC and Scl-Ab, Tb-BV/TV increased by 60-125 %, apparent bone strength of the lumbar vertebrae by 30-70 %, FS-BV by 10-18 %, and FS-apparent strength by 13-15 %, as compared to GC vehicle-treated mice. GC treatment at 4 mg/kg/day reduced the number of autophagic osteoblasts by 70 % on the vertebral trabecular bone surface compared to the placebo group (PL, GC 0 mg), and GC + Scl-Ab treatment. CONCLUSIONS Treatment with Scl-Ab prevented GC-induced reduction in both trabecular and cortical bone mass and strength and appeared to maintain osteoblast activity through autophagy.
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Zheng X, Dai W, Chen X, Wang K, Zhang W, Liu L, Hou J. Caffeine reduces hepatic lipid accumulation through regulation of lipogenesis and ER stress in zebrafish larvae. J Biomed Sci 2015; 22:105. [PMID: 26572131 PMCID: PMC4647812 DOI: 10.1186/s12929-015-0206-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 10/16/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Caffeine, the main component of coffee, has showed its protective effect on non-alcoholic fatty liver disease (NAFLD) in many studies. However, the hepatoprotection of caffeine and its mechanisms in zebrafish were unexplored. Thus, this study's intentions are to establish a NAFLD model of zebrafish larvae and to examine the role of caffeine on fatty liver with the model. RESULTS Growth and the incidence of fatty liver of zebrafish larvae increased with the increased amount of feeding in a dose-dependent manner. The degree of hepatic steatosis of larvae also gradually aggravated with the increased quantity and duration of feeding. Triglyceride contents of zebrafish fed for 20 days significantly increased in model group (180 mg/d) compared with control group (30 mg/d) (P < 0.001). Significant decreases in body weight and hepatic steatosis rate were observed in 2.5, 5, 8 % caffeine treatment group compared with model group (P < 0.05). Hepatic lipid accumulation was also significantly reduced in caffeine treatment larvae. Moreover, caffeine treatment was associated with upregulation of lipid β-oxidation gene ACO and downregulation of lipogenesis-associated genes (SREBP1, ACC1, CD36 and UCP2), ER stress-associated genes (PERK, IRE1, ATF6 and BIP), the inflammatory cytokine genes (IL-1beta and TNF-alpha) and autophagy associated genes (ATG12 and Beclin-1). Protein expression of CHOP, BIP and IL-1beta remarkably reduced in caffeine treatment group compared with model group. CONCLUSIONS We induced hepatoteatosis in zebrafish by overfeeding regimen and demonstrated caffeine have a role in suppression of hepatosteatosis by downregulation of genes associated with lipogenesis, ER stress, inflammatory response and enhancement of lipid oxidation, indicating zebrafish model may be used to identify putative pharmacological targets and to test novel drugs for human NAFLD treatment.
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Dai W, Liu M, Zhuang X, Li Q, Wang D. Mediastinal small cell carcinoma: a unique clinical entity? Clin Transl Oncol 2015; 18:515-20. [PMID: 26329297 DOI: 10.1007/s12094-015-1398-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 08/19/2015] [Indexed: 01/31/2023]
Abstract
PURPOSE Mediastinal small cell carcinoma (MSCC) is a rare tumor with limited published literature. In view of diagnostic confusion pertaining to this tumor, we investigated its origin, clinical features, management and survival. METHODS Clinical data of MSCC patients were retrospectively reviewed. Eligible patients showed pathologically proven small cell carcinoma (SCC) with the primary lesions confined to the mediastinum. Survival information was collected through follow-up studies. RESULTS Among 25 MSCC patients identified, 22 were classified to have limited disease (LD), while 3 were with extensive disease (ED). The 5 patients (20%) underwent surgery and 20 patients (80%) underwent non-surgical treatment. The 4 patients with LD MSCC received chemotherapy alone, while 13 of them received chemoradiotherapy. Overall median survival time (MST) of all patients was 22 months, and the 1-, 3- and 5-year overall survival rates were 67.4, 16.8, and 8.4%, respectively. The MST of LD and ED patients separately was 23 and 8 months, respectively, with significant difference (P = 0.005). But, the MST of patients who received surgical and non-surgical treatment was 25 and 21 months, respectively, with no significant difference (P = 0.757). The MST of LD patients receiving chemotherapy and chemoradiotherapy was 12 and 29 months, respectively, but somehow did not show significant difference (P = 0.482). CONCLUSIONS Our data suggested that MSCC may be a separate clinical entity like extrapulmonary small cell carcinomas (EPSCCs). Despite, multimodal treatment is currently the main treatment option, but for patients with LD MSCC, chemoradiotherapy is recommended to be preferred treatment modality.
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Zhang W, Dai W, Tsai SM, Zehnder SM, Sarntinoranont M, Angelini TE. Surface indentation and fluid intake generated by the polymer matrix of Bacillus subtilis biofilms. SOFT MATTER 2015; 11:3612-3617. [PMID: 25797701 DOI: 10.1039/c5sm00148j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Bacterial biofilms are highly structured, surface associated bacteria colonies held together by a cell-generated polymer network known as EPS (extracellular polymeric substance). This polymer network assists in adhesion to surfaces and generates spreading forces as colonies grow over time. In the laboratory and in nature, biofilms often grow at the interface between air and an elastic, semi-permeable nutrient source. As this type of biofilm increases in volume, an accommodating compression of its substrate may arise, potentially driven by the osmotic pressure exerted by the EPS against the substrate surface. Here we study Bacillus subtilis biofilm force generation by measuring the magnitude and rate of deformation imposed by colonies against the agar-nutrient slabs on which they grow. We find that the elastic stress stored in deformed agar is orders of magnitude larger than the drag stress associated with pulling fluid through the agar matrix. The stress exerted by the biofilm is nearly the same as the osmotic pressure generated by the EPS, and mutant colonies incapable of producing EPS exert much lower levels of stress. The fluid flow rate into B. subtilis biofilms suggest that EPS generated pressure provides some metabolic benefit as colonies expand in volume. These results reveal that long-term biofouling and colony expansion may be tied to the hydraulic permeability and elasticity of the surfaces that biofilms colonize.
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Dai W, Zhou FB, Wei C, Wang XW, Guo S, Yi XL, Li K, Gao TW, Liu L, Li CY. A functional single-nucleotide polymorphism in the ERCC1 gene alters the efficacy of narrowband ultraviolet B therapy in patients with active vitiligo in a Chinese population. Br J Dermatol 2015; 173:457-63. [PMID: 25965418 DOI: 10.1111/bjd.13892] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/27/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND T lymphocytes have been shown to cause the destruction of melanocytes in vitiligo pathogenesis. Narrowband ultraviolet B (NB-UVB), as an effective therapeutic strategy in vitiligo, can lead to the formation of DNA photoproducts such as cyclobutane pyrimidine dimers (CPDs) in perilesional lymphocytes and thus induce skin immunosuppression. The repair of DNA photoproducts is performed mainly through the nucleotide excision repair (NER) pathway. We hypothesized that single-nucleotide polymorphisms (SNPs) in NER genes might influence the repair capacity of CPDs and thus contribute to variations in phototherapy efficiency. OBJECTIVES To detect genetic polymorphisms in NER genes and their relationship with the efficacy of NB-UVB therapy in patients with active vitiligo. METHODS We investigated the association of NER SNPs (XPA A23G, XPC Ci11A, XPC C2919A and ERCC1 C118T) with phototherapy efficacy in 86 patients with vitiligo who received NB-UVB treatment. Furthermore, we examined the impact of ERCC1 C118T on the apoptosis of T lymphocytes and CPD accumulation after NB-UVB irradiation. RESULTS We found that patients with vitiligo with the ERCC1 codon 118 CC genotype showed better efficacy after NB-UVB irradiation than those with the ERCC1 118 TT and CT genotypes, whereas no such association was documented among the genotypes of XPA A23G, XPC Ci11A or XPC C2919A. Additionally, the apoptosis rates and CPD levels of lymphocytes after NB-UVB irradiation in patients with the ERCC1 118 CC genotype were significantly higher than those in patients with the ERCC1 118 TT and CT genotypes. CONCLUSIONS The ERCC1 118 CC genotype confers better efficacy of NB-UVB therapy in patients with active vitiligo.
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Ai JG, Zhao F, Gao ZM, Dai W, Zhang L, Chen HB, Zhou JG. Treatment of seawater immersion-complicated open-knee joint fracture. GENETICS AND MOLECULAR RESEARCH 2014; 13:5523-33. [PMID: 25117308 DOI: 10.4238/2014.july.25.6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The current study aimed to select suitable remedies for seawater immersion-complicated open-knee joint fracture by exploring the effects of different treatment methods. Forty adult rabbits weighing 2.20 ± 0.25 kg were divided equally into internal fracture fixation group (A), seawater-immersed group with primary internal fixation (B), seawater-immersed group with secondary internal fixation (C), and seawater-immersed group with external fixation (D), using the random-digit table method. Open-femoral internal condylar fracture models were established. Group A was left untreated for 2 h, whereas the other three groups were subjected to seawater immersion for 2 h. Afterwards, groups A and B underwent debridement and steel plate and screw internal fixation. Group C underwent debridement and external fixation, which was followed by secondary steel plate and screw internal fixation after the wound healed. Group D underwent transarticular arthrodesis. Wound infection, joint functional rehabilitation, and radiological and histopathological changes in fracture healing in each group were assessed. The results showed that delayed internal fixation effectively reduces the infection rate of seawater immersion-complicated open fracture and benefits joint function rehabilitation.
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Kwan H, Dai W, Chan C, Tong T, Lee K, Pan S, Wu Y, Tse K, Yu Z, Fong W. Lipidomic-based study of the regulatory role of schisandrin B on fatty acid production in a hepatic steatosis mouse model. PHARMANUTRITION 2014. [DOI: 10.1016/j.phanu.2013.11.089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Amugongo SK, Yao W, Jia J, Lay YAE, Dai W, Jiang L, Walsh D, Li CS, Dave NKN, Olivera D, Panganiban B, Ritchie RO, Lane NE. Effects of sequential osteoporosis treatments on trabecular bone in adult rats with low bone mass. Osteoporos Int 2014; 25:1735-50. [PMID: 24722767 PMCID: PMC4394748 DOI: 10.1007/s00198-014-2678-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 09/03/2013] [Indexed: 10/25/2022]
Abstract
UNLABELLED We used an osteopenic adult ovariectomized (OVX) rat model to evaluate various sequential treatments for osteoporosis, using FDA-approved agents with complementary tissue-level mechanisms of action. Sequential treatment for 3 months each with alendronate (Aln), followed by PTH, followed by resumption of Aln, created the highest trabecular bone mass, best microarchitecture, and highest bone strength. INTRODUCTION Individual agents used to treat human osteoporosis reduce fracture risk by ∼ 50-60%. As agents that act with complementary mechanisms are available, sequential therapies that mix antiresorptive and anabolic agents could improve fracture risk reduction, when compared with monotherapies. METHODS We evaluated bone mass, bone microarchitecture, and bone strength in adult OVX, osteopenic rats, during different sequences of vehicle (Veh), parathyroid hormone (PTH), Aln, or raloxifene (Ral) in three 90-day treatment periods, over 9 months. Differences among groups were evaluated. The interrelationships of bone mass and microarchitecture endpoints and their relationship to bone strength were studied. RESULTS Estrogen deficiency caused bone loss. OVX rats treated with Aln monotherapy had significantly better bone mass, microarchitecture, and bone strength than untreated OVX rats. Rats treated with an Aln drug holiday had bone mass and microarchitecture similar to the Aln monotherapy group but with significantly lower bone strength. PTH-treated rats had markedly higher bone endpoints, but all were lost after PTH withdrawal without follow-up treatment. Rats treated with PTH followed by Aln had better bone endpoints than those treated with Aln monotherapy, PTH monotherapy, or an Aln holiday. Rats treated initially with Aln or Ral, then switched to PTH, also had better bone endpoints, than monotherapy treatment. Rats treated with Aln, then PTH, and returned to Aln had the highest values for all endpoints. CONCLUSION Our data indicate that antiresorptive therapy can be coupled with an anabolic agent, to produce and maintain better bone mass, microarchitecture, and strength than can be achieved with any monotherapy.
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Wang K, Liu L, Dai W, Chen X, Zheng X, Hou J. [Establishment of a hepatic fibrosis model induced by diethylnitrosamine in zebrafish]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2014; 34:777-782. [PMID: 24968829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
OBJECTIVE To establish a zebrafish model of liver fibrosis via diethylnitrosamine (DEN)-induced liver injury. METHODS A total of 120 wild-type 3-month-old zebrafish were randomly divided into DEN-treated group and control group. The survival rate and behavioral changes of each group were observed. After treatment with DEN for 2, 4, and 6 weeks, liver index was measured, and liver fibrosis was evaluated with HE staining, Gomori staining and Sirius red staining. RESULTS No obvious behavioral change was observed in DEN-treated group during the experiment. Compared with that in control group, the liver index of zebrafish in DEN-treated group showed no significantly changes at the time points of observation. Proliferation of reticulate fibers was found in 30% of zebrafish treated with DEN for 4 weeks, and the rate increased to 80% at 6 weeks when reticulate fibers and collagen fibers actively proliferated to result in fiber collapse and formation of fibrotic nodules. CONCLUSION A stable zebrafish liver fibrosis model was successfully established by inducing liver damage to facilitate studies of the pathogenesis of liver fibrosis and screening therapeutic drugs.
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Chen JX, Shi Q, Wang XW, Guo S, Dai W, Li K, Song P, Wei C, Wang G, Li CY, Gao TW. Genetic polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR) and risk of vitiligo in Han Chinese populations: a genotype-phenotype correlation study. Br J Dermatol 2014; 170:1092-9. [PMID: 24472005 DOI: 10.1111/bjd.12845] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2014] [Indexed: 12/19/2022]
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Wang L, Li K, Zhang Q, Zeng Y, Dai W, Su Y, Wang G, Tan Y, Jin Z, Yu X, Si T. Short-term effects of escitalopram on regional brain function in first-episode drug-naive patients with major depressive disorder assessed by resting-state functional magnetic resonance imaging. Psychol Med 2014; 44:1417-1426. [PMID: 23942213 DOI: 10.1017/s0033291713002031] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Most knowledge regarding the effects of antidepressant drugs is at the receptor level, distal from the nervous system effects that mediate their clinical efficacy. Using functional magnetic resonance imaging (fMRI), this study investigated the effects of escitalopram, a selective serotonin reuptake inhibitor (SSRI), on resting-state brain function in patients with major depressive disorder (MDD). METHOD Fourteen first-episode drug-naive MDD patients completed two fMRI scans before and after 8 weeks of escitalopram therapy. Scans were also acquired in 14 matched healthy subjects. Data were analyzed using the regional homogeneity (ReHo) approach. RESULTS Compared to controls, MDD patients before treatment demonstrated decreased ReHo in the frontal (right superior frontal gyrus), temporal (left middle and right inferior temporal gyri), parietal (right precuneus) and occipital (left superior occipital gyrus and right cuneus) cortices, and increased ReHo in the left dorsal medial prefrontal gyrus and left anterior lobe of the cerebellum. Compared to the unmedicated state, ReHo in the patients after treatment was decreased in the left dorsal medial prefrontal gyrus, the right insula and the bilateral thalamus, and increased in the right superior frontal gyrus. Compared to controls, patients after treatment displayed a ReHo decrease in the right precuneus and a ReHo increase in the left anterior lobe of the cerebellum. CONCLUSIONS Successful treatment with escitalopram may be associated with modulation of resting-state brain activity in regions within the fronto-limbic circuit. This study provides new insight into the effects of antidepressants on functional brain systems in MDD.
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Liu Z, Dai W, Jiang L, Cheng Y. Over-expression of LGR5 correlates with poor survival of colon cancer in mice as well as in patients. Neoplasma 2014; 61:177-85. [PMID: 24063790 DOI: 10.4149/neo_2014_016] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Leucine-rich repeat-containing G protein-coupled receptor 5(LGR5) was identified as the stem cell marker of colon cancer stem cells(CSCs),which were considered as the main criminal cells initiation and reinitiation of colon cancer. We intended to demonstrate and further explain the relationship between LGR5 and colon cancer in mice model and patients. In our research, we used transcriptional methods and immunohistochemistry to investigate the LGR5 gene and protein expression, examined proliferating cell nuclear antigen(PCNA) and Ki67 which were the classic markers for cell proliferation in LGR5 protein positive and negative colon cancer among mice model and patients. Our results showed that LGR5 mRNA and protein expression was significantly over-expressed in 193/366 patients and 24/40mice model with primary colon cancer contrasted with matched normal tissues; significantly higher LGR5 gene expression was detected in pT4 cases than that in pT3 cases; PCNA and Ki67 expression was much more increase in colon cancer cells with positive LGR5 expression than those with negative LGR5 expression;LGR5 positive cancer not only in mice model but also in patients have shorter survival rate compared with LGR5 negative cancer. All our study manifested that LGR5 took on an important effect in the initiation and progression of colon cancer, provided also more helpful evidence for clinical diagnosis and an useful indicator for adjuvant therapy.
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Tsui S, Dai W, Lu L. CCCTC-binding factor mediates effects of glucose on beta cell survival. Cell Prolif 2013; 47:28-37. [PMID: 24354619 DOI: 10.1111/cpr.12085] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 10/07/2013] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVES Pancreatic islet β-cell survival is paramount for regulation of insulin activity and for maintaining glucose homeostasis. Recently, Pax6 has been shown to be essential for many vital functions in β-cells, although many molecular mechanisms of its homeostasis in β-cells remain unclear. The present study investigates novel effects of glucose- and insulin-induced CCCTC-binding factor (CTCF) activity on Pax6 gene expression as well as for subsequent effects of insulin-activated signalling pathways, on β-cell proliferation. MATERIALS AND METHODS Pancreatic β-TC-1-6 cells were cultured in DMEM and stimulated with high concentrations of glucose (5-125 mm); cell viability was assessed by MTT assay. Effects of CTCF on Pax6 were evaluated in the high glucose-induced environment and CTCF/Erk-suppressed cells, by promoter reporter and western blotting analyses. RESULTS Increases in glucose and insulin concentrations upregulated CTCF and consequently downregulated Pax6 in β-cell survival and proliferation. Knocking-down CTCF directly affected Pax6 transcription through CTCF binding and blocked the response to glucose. Altered Erk activity mediated effects of CTCF on controlling Pax6 expression, which partially regulated β-cell proliferation. CONCLUSIONS CTCF functioned as a molecular mediator between insulin-induced upstream Erk signalling and Pax6 expression in these pancreatic β-cells. This pathway may contribute to regulation of β-cell survival and proliferation.
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Hu P, Dai W. Computer simulation and density functional theory study on relationship between structure of amino acid and inhibition performance. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/1433075x11y.0000000010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Lee RF, Dai W, Jones J. Decoupled circular-polarized dual-head volume coil pair for studying two interacting human brains with dyadic fMRI. Magn Reson Med 2012. [DOI: 10.1002/mrm.24521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Huang LW, Dai W, Alsop D, Waterston L, Inouye S, Fong T. Assessment of Cholinergic and Cognitive Function in Healthy Young Adults Using Pharmacologic ASL Perfusion MRI (S29.003). Neurology 2012. [DOI: 10.1212/wnl.78.1_meetingabstracts.s29.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Jiang X, Ellis N, Shen DK, Jiang J, Dai W, Zhong Z. Thermogravimetry-FTIR Analysis of Pyrolysis of Pyrolytic Lignin Extracted from Bio-Oil. Chem Eng Technol 2012. [DOI: 10.1002/ceat.201000400] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Lee RF, Dai W, Jones J. Decoupled circular-polarized dual-head volume coil pair for studying two interacting human brains with dyadic fMRI. Magn Reson Med 2011; 68:1087-96. [PMID: 22213428 DOI: 10.1002/mrm.23313] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 10/24/2011] [Accepted: 11/12/2011] [Indexed: 11/07/2022]
Abstract
A major function of the human brain is to mediate interactions with other people. Until recently, studying social interactions as they occur within the brain was not possible due to the lack of measurable methods to observe two interacting minds simultaneously. We have developed a novel MRI dual-head volume coil pair that can scan two subjects' brains simultaneously while the subjects are socially interacting in one MRI scanner. The feasibility of using this coil for dyadic functional MRI (fMRI) study has been successfully demonstrated for the first time. Meanwhile, an innovative robust scheme for decoupling two circular-polarized coils (not surface coils) is introduced in theory and validated in practice in the coil technology development.
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Dai W, Kloner RA. Bone marrow-derived cell transplantation therapy for myocardial infarction: lessons learned and future questions. Am J Transplant 2011; 11:2297-301. [PMID: 21929617 DOI: 10.1111/j.1600-6143.2011.03750.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Over the last decade, many investigators have utilized bone marrow-derived cells for cell transplantation therapy in animal studies and in patients with acute myocardial infarction and chronic heart failure. In those experimental and clinical studies, various doses and types of bone marrow-derived cells have been transplanted to the injured myocardium using a variety of approaches, such as intracoronary infusion or catheter-based direct endomyocardial injection, and at different time points after successful coronary reperfusion. The reported treatment effects are variable, which may be related to differences in cell type and quantity of transplanted cells, timing and approach of cell transplantation and patient selection. In this review, we summarize and discuss the controversies and questions related to the clinical use of bone marrow-derived cells.
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Zhao XG, Dai W, Li Y, Tian L. AUC-based biomarker ensemble with an application on gene scores predicting low bone mineral density. ACTA ACUST UNITED AC 2011; 27:3050-5. [PMID: 21908541 DOI: 10.1093/bioinformatics/btr516] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
MOTIVATION The area under the receiver operating characteristic (ROC) curve (AUC), long regarded as a 'golden' measure for the predictiveness of a continuous score, has propelled the need to develop AUC-based predictors. However, the AUC-based ensemble methods are rather scant, largely due to the fact that the associated objective function is neither continuous nor concave. Indeed, there is no reliable numerical algorithm identifying optimal combination of a set of biomarkers to maximize the AUC, especially when the number of biomarkers is large. RESULTS We have proposed a novel AUC-based statistical ensemble methods for combining multiple biomarkers to differentiate a binary response of interest. Specifically, we propose to replace the non-continuous and non-convex AUC objective function by a convex surrogate loss function, whose minimizer can be efficiently identified. With the established framework, the lasso and other regularization techniques enable feature selections. Extensive simulations have demonstrated the superiority of the new methods to the existing methods. The proposal has been applied to a gene expression dataset to construct gene expression scores to differentiate elderly women with low bone mineral density (BMD) and those with normal BMD. The AUCs of the resulting scores in the independent test dataset has been satisfactory. CONCLUSION Aiming for directly maximizing AUC, the proposed AUC-based ensemble method provides an efficient means of generating a stable combination of multiple biomarkers, which is especially useful under the high-dimensional settings. CONTACT lutian@stanford.edu. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Sriraksa R, Zeller C, El-Bahrawy MA, Dai W, Daduang J, Jearanaikoon P, Chau-in S, Brown R, Limpaiboon T. CpG-island methylation study of liver fluke-related cholangiocarcinoma. Br J Cancer 2011; 104:1313-8. [PMID: 21448164 PMCID: PMC3078588 DOI: 10.1038/bjc.2011.102] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 02/14/2011] [Accepted: 03/01/2011] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Genetic changes have been widely reported in association with cholangiocarcinoma (CCA), while epigenetic changes are poorly characterised. We aimed to further evaluate CpG-island hypermethylation in CCA at candidate loci, which may have potential as diagnostic or prognostic biomarkers. METHODS We analysed methylation of 26 CpG-islands in 102 liver fluke related-CCA and 29 adjacent normal samples using methylation-specific PCR (MSP). Methylation of interest loci was confirmed using pyrosequencing and/or combined bisulfite restriction analysis, and protein expression by immunohistochemistry. RESULTS A number of CpG-islands (OPCML, SFRP1, HIC1, PTEN and DcR1) showed frequency of hypermethylation in >28% of CCA, but not adjacent normal tissues. The results showed that 91% of CCA were methylated in at least one CpG-island. The OPCML was the most frequently methylated locus (72.5%) and was more frequently methylated in less differentiated CCA. Patients with methylated DcR1 had significantly longer overall survival (Median; 41.7 vs 21.7 weeks, P=0.027). Low-protein expression was found in >70% of CCA with methylation of OPCML or DcR1. CONCLUSION Aberrant hypermethylation of certain loci is a common event in liver fluke-related CCA and may potentially contribute to cholangiocarcinogenesis. The OPCML and DcR1 might serve as methylation biomarkers in CCA that can be readily examined by MSP.
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Nassar R, Wu X, Paun M, Dai W, Palmer J. A MATHEMATICAL MODEL CHARACTERIZING THE DIFFUSION PROPERTIES OF MICROCAPSULES. CHEM ENG COMMUN 2010. [DOI: 10.1080/00986445.2010.493109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Raji CA, Lee C, Lopez OL, Tsay J, Boardman JF, Schwartz ED, Bartynski WS, Hefzy HM, Gach HM, Dai W, Becker JT. Initial experience in using continuous arterial spin-labeled MR imaging for early detection of Alzheimer disease. AJNR Am J Neuroradiol 2010; 31:847-55. [PMID: 20075093 DOI: 10.3174/ajnr.a1955] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE MR imaging of the brain has significant potential in the early detection of neurodegenerative disorders such as AD. The purpose of this work was to determine if perfusion MR imaging can be used to separate AD from normal cognition in individual subjects. We investigated the diagnostic utility of perfusion MR imaging for early detection of AD compared with structural imaging. MATERIALS AND METHODS Data were analyzed from 32 participants in the institutional review board-approved CHS-CS: 19 cognitively healthy individuals and 13 with clinically adjudicated AD. All subjects underwent structural T1-weighted SGPR and CASL MR imaging. Four readers with varying experience separately rated each CASL and SPGR scan finding as normal or abnormal on the basis of standardized qualitative diagnostic criteria for observed perfusion abnormalities on CASL or volume loss on SPGR and rated the confidence in their evaluation. RESULTS Inter-rater reliability was superior in CASL (kappa = 0.7 in experienced readers) compared with SPGR (kappa = 0.17). CASL MR imaging had the highest sensitivity (85%) and accuracy (70%). Frontal lobe CASL findings increased sensitivity to 88% and accuracy to 79%. Fifty-seven percent of false-positive readings with CASL were in controls with cognitive decline or instability within 5 years. Three of the 4 readers revealed a statistically significant relationship between confidence and correct classification when using CASL. CONCLUSIONS Readers were able to separate individuals with mild AD from those with normal cognition with high sensitivity by using CASL but not volumetric MR imaging. This initial experience suggests that CASL MR imaging may be a useful technique for detecting AD.
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