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1.  The Future of Biologic Coatings for Orthopaedic Implants 
Biomaterials  2013;34(13):3174-3183.
Implants are widely used for othopaedic applications such as fixing fractures, repairing nonunions, obtaining a joint arthrodesis, total joint arthroplasty, spinal reconstruction, and soft tissue anchorage. Previously, orthopaedic implants were designed simply as mechanical devices; the biological aspects of the implant were a byproduct of stable internal/external fixation of the device to the surrounding bone or soft tissue. More recently, biologic coatings have been incorporated into orthopaedic implants in order to modulate the surrounding biological environment. This opinion article reviews current and potential future use of biologic coatings for orthopaedic implants to facilitate osseointegration and mitigate possible adverse tissue responses including the foreign body reaction and implant infection. While many of these coatings are still in the preclinical testing stage, bioengineers, material scientists and surgeons continue to explore surface coatings as a means of improving clinical outcome of patients undergoing orthopaedic surgery.
PMCID: PMC3582840  PMID: 23391496
implant coatings; orthopaedics; osseointegration; calcium phosphate coatings; biomolecule coatings; infection; foreign body reaction
2.  CD90 (Thy-1)-Positive Selection Enhances Osteogenic Capacity of Human Adipose-Derived Stromal Cells 
Tissue Engineering. Part A  2013;19(7-8):989-997.
Stem cell-based bone tissue engineering with adipose-derived stromal cells (ASCs) has shown great promise for revolutionizing treatment of large bone deficits. However, there is still a lack of consensus on cell surface markers identifying osteoprogenitors. Fluorescence-activated cell sorting has identified a subpopulation of CD105low cells with enhanced osteogenic differentiation. The purpose of the present study was to compare the ability of CD90 (Thy-1) to identify osteoprogenitors relative to CD105.
Unsorted cells, CD90+, CD90−, CD105high, and CD105low cells were treated with an osteogenic differentiation medium. For evaluation of in vitro osteogenesis, alkaline phosphatase (ALP) staining and alizarin red staining were performed at 7 days and 14 days, respectively. RNA was harvested after 7 and 14 days of differentiation, and osteogenic gene expression was examined by quantitative real-time polymerase chain reaction. For evaluation of in vivo osteogenesis, critical-sized (4-mm) calvarial defects in nude mice were treated with the hydroxyapatite-poly(lactic-co-glycolic acid) scaffold seeded with the above-mentioned subpopulations. Healing was followed using micro-CT scans for 8 weeks. Calvaria were harvested at 8 weeks postoperatively, and sections were stained with Movat's Pentachrome.
Transcriptional analysis revealed that the CD90+ subpopulation was enriched for a more osteogenic subtype relative to the CD105low subpopulation. Staining at day 7 for ALP was greatest in the CD90+ cells, followed by the CD105low cells. Staining at day 14 for alizarin red demonstrated the greatest amount of mineralized extracellular matrix in the CD90+ cells, again followed by the CD105low cells. Quantification of in vivo healing at 2, 4, 6, and 8weeks postoperatively demonstrated increased bone formation in defects treated with CD90+ ASCs relative to all other groups. On Movat's Pentachrome-stained sections, defects treated with CD90+ cells showed the most robust bony regeneration. Defects treated with CD90− cells, CD105high cells, and CD105low cells demonstrated some bone formation, but to a lesser degree when compared with the CD90+ group.
While CD105low cells have previously been shown to possess an enhanced osteogenic potential, we found that CD90+ cells are more capable of forming bone both in vitro and in vivo. These data therefore suggest that CD90 may be a more effective marker than CD105 to isolate a highly osteogenic subpopulation for bone tissue engineering.
PMCID: PMC3589870  PMID: 23216074
3.  Inhibition of Enterovirus 71 Replication by 7-Hydroxyflavone and Diisopropyl-Flavon7-yl Phosphate 
PLoS ONE  2014;9(3):e92565.
Enterovirus 71 (EV71) is the major causative agent of hand, foot, and mouth disease, which has been continuously prevalent in Asia in recent years. In children, severe cases can lead to death, and no prophylactic or therapeutic measures against EV71 infection are available. The 3C proteases of EV71 play an important role in viral replication and are an ideal drug target. In previous work, we resolved the crystal structure for EV71 3Cpro. In this report, we took advantage of the automated docking program AutoDock 4.0 to simulate EV71 3Cpro-ligand conformation. 7-hydroxyflavone (HF) and its phosphate ester(FIP) were predicted to bind with EV71 3Cpro.In an in vitro protease inhibition assay, FIP inhibited EV71 3Cpro protease activity. Both flavones were highly active against EV71, protecting cells from EV71 infection. Replication of viral RNA and formation of EV71 plaque were all strongly inhibited in cells. These results indicated that HF and FIP may serve as potential protective agents in the treatment of patients with chronic EV71 infection.
PMCID: PMC3963929  PMID: 24664133
4.  Increased Plasma DPP4 Activity Is an Independent Predictor of the Onset of Metabolic Syndrome in Chinese over 4 Years: Result from the China National Diabetes and Metabolic Disorders Study 
PLoS ONE  2014;9(3):e92222.
To determine whether fasting plasma Dipeptidyl Peptidase 4 (DPP4) activity and active Glucagon-Like Peptide-1 (GLP-1) were predictive of the onset of metabolic syndrome.
A prospective cohort study was conducted of 2042 adults (863 men and 1,179 women) aged 18-70 years without metabolic syndrome examined in 2007(baseline) and 2011(follow-up). Baseline plasma DPP4 activity was determined as the rate of cleavage of 7-amino-4- methylcoumarin (AMC) from the synthetic substrate H-glycyl-prolyl-AMC and active GLP-1 was determined by enzymoimmunoassay.
During an average of 4 years of follow-up, 131 men (15.2%) and 174 women (14.8%) developed metabolic syndrome. In multiple linear regression analysis, baseline DPP4 activity was an independent predictor of an increase in insulin resistance over a 4-year period (P<0.01). In multivariable-adjusted models, the odds ratio (OR) for incident metabolic syndrome comparing the highest with the lowest quartiles of DPP4 activity and active GLP-1 were 2.82, 0.45 for men and 2.48, 0.36 for women respectively. Furthermore, plasma DPP4 activity significantly improved the area under the ROC curve for predicting new-onset metabolic syndrome based on information from metabolic syndrome components (Both P<0.01).
DPP4 activity is an important predictor of the onset of insulin resistance and metabolic syndrome in apparently healthy Chinese men and women. This finding may have important implications for understanding the aetiology of metabolic syndrome.
Trial Registration
#TR-CCH-Chi CTR-CCH-00000361
PMCID: PMC3960228  PMID: 24647445
5.  Delivery of Small Interfering RNA for Inhibition of Endothelial Cell Apoptosis by Hypoxia and Serum Deprivation 
RNA interference (RNAi) for anti-angiogenic or pro-apoptotic factors in endothelial cells (ECs) has great potential for the treatment of ischemic diseases by promoting angiogenesis or inhibiting apoptosis. Here, we report the utility of small interfering RNA (siRNA) in inhibiting EC apoptosis induced by tumor necrosis factor-α (TNF-α). siRNA was designed and synthesized targeting tumor necrosis factor-α receptor-1 (TNFR-1) and Src homology 2 domain-containing protein tyrosine phosphatase-1 (SHP-1). Human umbilical vein endothelial cells (HUVECs) were cultured under in vitro hypoxic and serum-deprived conditions to simulate in vivo ischemic conditions. Two days after liposomal delivery of siRNA targeting TNFR-1 and SHP-1, significant silencing of each target (TNFR-1; 76.5 % and SHP-1; 97.2 %) was detected. Under serum-deprived hypoxic (1% oxygen) conditions, TNF-α expression in HUVECs increased relative to normoxic (20% oxygen) and serum-containing conditions. Despite enhanced TNF-α expression, suppression of TNFR-1 or SHP-1 by siRNA delivery not only enhanced expression of angiogenic factors (KDR/Flk-1 and eNOS) and anti-apoptotic factor (Bcl-xL) but also reduced expression of a pro-apoptotic factor (Bax). Transfection of TNFR-1 or SHP-1 siRNA significantly decreased the HUVEC apoptosis while significantly enhancing HUVEC proliferation and capillary formation. The present study demonstrates that TNFR-1 and SHP-1 may be useful targets for the treatment of myocardial or hindlimb ischemia.
PMCID: PMC3957099  PMID: 18765230
RNA interference; Endothelial cell; Hypoxia; Serum Deprivation; Apoptosis
6.  Identification and Characterization of a Ste20-Like Kinase in Artemia and Its Role in the Developmental Regulation and Resistance to Environmental Stress 
PLoS ONE  2014;9(3):e92234.
To adapt to extreme environments, the crustacean Artemia has evolved two alternative reproductive pathways. During ovoviviparous (direct) development, nauplius larvae are produced. In contrast, Artemia females release encysted diapause embryos (cysts) via the oviparous pathway. To date, the cellular mechanisms that regulate stress resistance of Artemia remain largely unknown. Ste20-like kinase (SLK) participates in multiple biological processes, including stress responses, apoptosis, and cell cycle progression.
Principal Finding
We isolated and characterized a member of the SLK superfamily termed ArSLK from Artemia parthenogenetica. The ArSLK gene is transcribed throughout both ovoviviparous and oviparous development; however, the protein is located mainly in the nuclei of stress-resistant diapause cysts, unlike the nauplii and nauplius-destined embryos where it is cytoplasmic. Interestingly, exposure of nauplii to heat shock, acidic pH, and UV irradiation induced the translocation of ArSLK from cytoplasm to nucleus. This translocation was reversed following stress removal. Moreover, under physiologically-stressful conditions, the nauplius larvae produced by adults after gene knockdown of endogenous ArSLK by RNAi, lost the ability of free-swimming much earlier than those of control larvae from females injected with GFP dsRNA.
Taken together, this study demonstrated that trafficking of ArSLK between the cytoplasm and the nucleus participates in regulating the stress resistance of Artemia. Our findings may provide significant insight into the functions of members of the SLK superfamily.
PMCID: PMC3956927  PMID: 24637947
7.  Anti-Enterovirus 71 Effects of Chrysin and Its Phosphate Ester 
PLoS ONE  2014;9(3):e89668.
Enterovirus 71 (EV71) can cause severe disease and even lead to death in children, and an effective antiviral drug is currently unavailable. The anti-EV71 effect of chrysin (5,7-dihydroxyflavone), a natural flavonoid commonly found in many plants, was tested in this report. By using the predicting program Autodock 4.0 and an in vitro protease inhibition assay, we found that chrysin could suppress viral 3Cpro activity. Replication of viral RNA and production of viral capsid protein and the infectious virion were strongly inhibited by chrysin, without noticeable cytotoxicity. Cytopathic effects on cells were also prevented. Diisopropyl chrysin-7-yl phosphate (CPI), the phosphate ester for chrysin, was generated through a simplified Atheron-Todd reaction to achieve stronger anti-viral activity. CPI was also able to bind with and inhibit viral 3Cpro activity in vitro. As expected, CPI demonstrated more potent antiviral activity against EV71.
PMCID: PMC3943725  PMID: 24598537
8.  Recombinant Human Coxsackievirus B3 from Children with Acute Myocarditis in China 
Journal of Clinical Microbiology  2013;51(9):3083-3086.
Recombination events were found in two human coxsackievirus B3 strains, Beijing0811 and SD2012CHN. The strains were isolated separately from five newborns diagnosed with severe hospital-acquired acute myocarditis in Beijing in 2008 and from two children diagnosed with hand, foot, and mouth disease with concurrent acute myocarditis in Shandong in 2012.
PMCID: PMC3754657  PMID: 23804378
9.  Clinical Analysis of Cause, Treatment and Prognosis in Acute Kidney Injury Patients 
PLoS ONE  2014;9(2):e85214.
Acute kidney injury (AKI) is characterized by an abrupt decline in renal function, resulting in an inability to secrete waste products and maintain electrolyte and water balance, and is associated with high risks of morbidity and mortality. This study retrospectively analyzed clinical data, treatment, and prognosis of 271 hospitalized patients (172 males and 99 females) diagnosed with AKI from December, 2008 to December, 2011. In addition, this study explored the association between the cause of AKI and prognosis, severity and treatment of AKI. The severity of AKI was classified according to the Acute Kidney Injury Network (AKIN) criteria. Renal recovery was defined as a decrease in a serum creatinine level to the normal value. Prerenal, renal, and postrenal causes accounted for 36.5% (99 patients), 46.5% (126 patients) and 17.0% (46 patients), respectively, of the incidence of AKI. Conservative, surgical, and renal replacement treatments were given to 180 (66.4%), 30 (11.1%) and 61 patients (22.5%), respectively. The overall recovery rate was 21.0%, and the mortality rate was 19.6%. Levels of Cl−, Na+ and carbon dioxide combining power decreased with increasing severity of AKI. Cause and treatment were significantly associated with AKI prognosis. Likewise, the severity of AKI was significantly associated with cause, treatment and prognosis. Multivariate logistic regression analysis found that respiratory injury and multiple organ dysfunction syndrome (MODS) were associated with AKI patient death. Cause, treatment and AKIN stage are associated with the prognosis of AKI. Respiratory injury and MODS are prognostic factors for death of AKI patients.
PMCID: PMC3931618  PMID: 24586237
10.  GSTT1 Deletion Is Related to Polycyclic Aromatic Hydrocarbons-Induced DNA Damage and Lymphoma Progression 
PLoS ONE  2014;9(2):e89302.
The interrelationship between genetic susceptibility and carcinogenic exposure is important in cancer development. Polymorphisms in detoxification enzymes of the glutathione-S-transferases (GST) family are associated with an increased incidence of lymphoma. Here we investigated the molecular connection of the genetic polymorphism of GSTT1 to the response of lymphocytes to polycyclic aromatic hydrocarbons (PAH). In neoplastic situation, GSTT1 deletions were more frequently observed in lymphoma patients (54.9%) than in normal controls (42.0%, P = 0.009), resulting in an increased risk for lymphoma in individuals with GSTT1-null genotype (Odds ratio = 1.698, 95% confidence interval = 1.145–2.518). GSTT1 gene and protein expression were accordingly decreased in GSTT1-deleting patients, consistent with activated profile of cell cycle regulation genes. Mimicking environmental exposure using long-term repeat culture with low-dose PAH metabolite Hydroquinone, malignant B- and T-lymphocytes presented increased DNA damage, pCHK1/MYC expression and cell proliferation, which were counteracted by ectopic expression of GSTT1. Moreover, GSTT1 expression retarded xenograft tumor formation of Hydroquinone-treated lymphoma cells in nude mice. In non-neoplastic situation, when zebrafish was exposed to PAH Benzo(a)pyrene, molecular silencing of gstt1 enhanced the proliferation of normal lymphocytes and upregulated myca expression. Collectively, these findings suggested that GSTT1 deletion is related to genetic predisposition to lymphoma, particularly interacting with environmental pollutants containing PAH.
PMCID: PMC3930712  PMID: 24586676
11.  New Stabilization for Dynamical System with Two Additive Time-Varying Delays 
The Scientific World Journal  2014;2014:315817.
This paper provides a new delay-dependent stabilization criterion for systems with two additive time-varying delays. The novel functional is constructed, a tighter upper bound of the derivative of the Lyapunov functional is obtained. These results have advantages over some existing ones because the combination of the delay decomposition technique and the reciprocally convex approach. Two examples are provided to demonstrate the less conservatism and effectiveness of the results in this paper.
PMCID: PMC3948470
12.  Association of High Vitamin D Status with Low Circulating Thyroid-Stimulating Hormone Independent of Thyroid Hormone Levels in Middle-Aged and Elderly Males 
Background. A recent study has reported that high circulating 25-hydroxyvitamin D [25(OH)D] is associated with low circulating thyroid-stimulating hormone (TSH) levels, but only in younger individuals. The goal of the present study was to explore the relationship between vitamin D status and circulating TSH levels with thyroid autoimmunity and thyroid hormone levels taken into consideration in a population-based health survey of middle-aged and elderly individuals. Methods. A total of 1,424 Chinese adults, aged 41–78 years, were enrolled in this cross-sectional study. Serum levels of 25(OH)D, TSH, thyroid hormones, and thyroid autoantibodies were measured. Results. The prevalence of vitamin D insufficiency was 94.29% in males and 97.22% in females, and the prevalence of vitamin D deficiency was 55.61% in males and 69.64% in females. Vitamin D status was not associated with positive thyroid autoantibodies after controlling for age, gender, body mass index, and smoking status. Higher 25(OH)D levels were associated with lower TSH levels after controlling for age, FT4 and FT3 levels, thyroid volume, the presence of thyroid nodule(s), and smoking status in males. Conclusion. High vitamin D status in middle-aged and elderly males was associated with low circulating TSH levels independent of thyroid hormone levels.
PMCID: PMC3947886
13.  White matter abnormalities in adolescents with generalized anxiety disorder: a diffusion tensor imaging study 
BMC Psychiatry  2014;14:41.
Previous neuroimaging studies have suggested an abnormal neural circuitry of emotion regulation including the amygdala and prefrontal cortex in both adult and adolescent generalized anxiety disorder (GAD) patients. Aberrant integrity of white matter in this neural circuitry has been verified in adult GAD patients. White matter abnormalities in adolescent GAD patients have not been detected.
Twenty-five adolescents with GAD and 24 healthy controls underwent a diffusion tensor imaging scan. Fractional anisotropy (FA) was compared between groups with a voxel-wise Tract-Based Spatial Statistics (TBSS) analysis method.
Compared with healthy controls, adolescents with GAD showed significantly reduced FA in bilateral uncinate fasciculus, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, and corona radiata.
The findings in the present study suggest a neural basis of emotion dysregulation in adolescent GAD patients.
PMCID: PMC3937009  PMID: 24528558
Generalized anxiety disorder; Adolescent; Diffusion tensor imaging; Fractional anisotropy
14.  Paracrine Release from Nonviral Engineered Adipose-Derived Stem Cells Promotes Endothelial Cell Survival and Migration In Vitro 
Stem Cells and Development  2012;22(3):483-491.
Stem cells hold great potential for therapeutic angiogenesis due to their ability to directly contribute to new vessel formation or secrete paracrine signals. Adipose-derived stem cells (ADSCs) are a particularly attractive autologous cell source for therapeutic angiogenesis due to their ease of isolation and relative abundance. Gene therapy may be used to further enhance the therapeutic efficacy of ADSCs by overexpressing desired therapeutic factors. Here, we developed vascular endothelial growth factor (VEGF)–overexpressing ADSCs utilizing poly(β-amino esters) (PBAEs), a hydrolytically biodegradable polymer, and examined the effects of paracrine release from nonviral modified ADSCs on the angiogenic potential of human umbilical vein endothelial cells (HUVECs) in vitro. PBAE polymeric vectors delivered DNA into ADSCs with high efficiency and low cytotoxicity, leading to an over 3-fold increase in VEGF production by ADSCs compared with Lipofectamine 2000. Paracrine release from PBAE/VEGF-transfected ADSCs enhanced HUVEC viability and decreased HUVEC apoptosis under hypoxia. Further, paracrine release from PBAE/VEGF-transfected ADSCs significantly enhanced HUVEC migration and tube formation, two critical cellular processes for effective angiogenesis. Our results demonstrate that genetically engineered ADSCs using biodegradable polymeric nanoparticles may provide a promising autologous cell source for therapeutic angiogenesis in treating cardiovascular diseases.
PMCID: PMC3549626  PMID: 22889246
15.  An Unconventional Antigen Translated by a Novel Internal Ribosome Entry Site Elicits Antitumor Humoral Immune Reactions1 
Self-tumor Ags that elicit antitumor immune responses in responses to IFN-α stimulation remain poorly defined. We screened a human testis cDNA library with sera from three polycythemia vera patients who responded to IFN-α and identified a novel Ag, MPD6. MPD6 belongs to the group of cryptic Ags without conventional genomic structure and is encoded by a cryptic open reading frame located in the 3′-untranslated region of myotrophin mRNA. MPD6 elicits IgG Ab responses in a subset of polycythemia vera patients, as well as patients with chronic myelogenous leukemia and prostate cancer, suggesting that it is broadly immunogenic. The expression of myotrophin-MPD6 transcripts was upregulated in some tumor cells, but only slightly increased in K562 cells in response to IFN-α treatment. By using bicistronic reporter constructs, we showed that the translation of MPD6 was mediated by a novel internal ribosome entry site (IRES) upstream of the MPD6 reading frame. Furthermore, the MPD6-IRES-mediated translation, but not myotrophin-MPD6 transcription, was significantly upregulated in response to IFN-α stimulation. These findings demonstrate that a novel IRES-mediated mechanism may be responsible for the translation of unconventional self-Ag MPD6 in responsive to IFN-α stimulation. The eliciting antitumor immune response against unconventional Ag MPD6 in patients with myeloproliferative diseases suggests MPD6 as a potential target of novel immunotherapy.
PMCID: PMC3902139  PMID: 16982933
16.  An N-terminal region of translationally controlled tumor protein is required for its antiapoptotic activity 
Oncogene  2005;24(30):4778-4788.
Bcl-xL plays a critical role in maintaining cell survival. However, the relationship between the potential interaction of Bcl-xL with other cytosolic proteins and the regulation of cell survival remains incompletely defined. We have identified translationally controlled tumor protein (TCTP), a multifunctional protein, as a novel antiapoptotic Bcl-xL-interacting protein. TCTP interacted in vivo and in vitro with Bcl-xL, and their sites have been mapped to an N-terminal region of TCTP and the Bcl-2 homology domain 3 of Bcl-xL. Consistent with a role in maintaining T-cell survival during activation, TCTP was significantly upregulated in murine T cells activated by T-cell antigen receptor (TCR) ligation and CD28 costimulation, which was correlated with the upregulation of Bcl-xL in activated T cells. Moreover, downregulation of TCTP expression by antisense technology in T cells results in the increase of T-cell apoptosis. Furthermore, the N-terminal region of TCTP was required for its ability to inhibit apoptosis. In conclusion, this study has demonstrated that an N-terminal region of a cytosolic protein, TCTP, is required for its binding to Bcl-xL and for its antiapoptotic activity.
PMCID: PMC3901995  PMID: 15870695
Bcl-xL; TCTP; apoptosis; protein interaction
17.  A Novel Mechanism of Alternative Promoter and Splicing Regulates the Epitope Generation of Tumor Antigen CML66-L1 
This report describes the difference in the epitope generation of two isoforms of self-tumor Ag CML66 and the regulation mechanism. We identified a new CML66 short isoform, termed CML66-S. The previously identified long CML66 is referred to as CML66-L. CML66-S shares the C terminus with CML66-L but has its unique N terminus. CML66-S is predominantly expressed in testis, but is also expressed in very low levels in tumor cells, whereas CML66-L is expressed in tumor cells and testis. Differential expression of CML66-L and CML66-S in tumor cells resulted from regulation at transcription, although alternative splicing also participated in the generation of the isoforms. In addition, Ab titers to a CML66-L peptide were significantly higher than that to CML66-S peptide in the sera from patients with tumors. Finally, the Abs to full-length CML66-L in the sera from patients with tumors were correlated with the Abs in the sera from these patients to CML66-L-38, which is a fusion protein with a CML66-L-specific N terminus. This suggests that the CML66-L isoform is mainly responsible for the epitope generation. Our studies have identified the alternative promoter in combination with alternative splicing as a novel mechanism for regulation of the epitope generation of a self-tumor Ag.
PMCID: PMC3901998  PMID: 14688378
18.  Increased noncanonical splicing of autoantigen transcripts provides the structural basis for expression of untolerized epitopes 
Alternative splicing is important for increasing the complexity of the human proteome from a limited genome. Previous studies have shown that for some autoantigens, there is differential immunogenicity among alternatively spliced isoforms.
Herein, we tested the hypothesis that alternative splicing is a common feature for transcripts of autologous proteins that are autoantigens. The corollary hypothesis tested was that nonautoantigen transcripts have a lower frequency of alternative splicing.
The extent of alternative splicing within 45 randomly selected self-proteins associated with autoimmune diseases was compared with 9554 randomly selected proteins in the human genome by using bioinformatics analyses. Isoform-specific regions that resulted from alternative splicing were studied for their potential to be epitopes for antibodies or T-cell receptors.
Alternative splicing occurred in 100% of the autoantigen transcripts. This was significantly higher than the approximately 42% rate of alternative splicing observed in the 9554 randomly selected human gene transcripts (P < .001). Within the isoform-specific regions of the autoantigens, 92% and 88% encoded MHC class I and class II–restricted T-cell antigen epitopes, respectively, and 70% encoded antibody binding domains. Furthermore, 80% of the autoantigen transcripts underwent noncanonical alternative splicing, which is also significantly higher than the less than 1% rate in randomly selected gene transcripts (P < .001).
These studies suggest that noncanonical alternative splicing may be an important mechanism for the generation of untolerized epitopes that may lead to autoimmunity.
Furthermore, the product of a transcript that does not undergo alternative splicing is unlikely to be a target antigen in autoimmunity.
PMCID: PMC3902068  PMID: 15577853
Autoantigens; alternative splicing; exons; isoforms; antigen epitopes; immunogenicity; immune tolerance; autoimmune diseases
19.  ADAM10 Negatively Regulates Neuronal Differentiation during Spinal Cord Development 
PLoS ONE  2014;9(1):e84617.
Members of the ADAM (a disintegrin and metalloprotease) family are involved in embryogenesis and tissue formation via their proteolytic function, cell-cell and cell-matrix interactions. ADAM10 is expressed temporally and spatially in the developing chicken spinal cord, but its function remains elusive. In the present study, we address this question by electroporating ADAM10 specific morpholino antisense oligonucleotides (ADAM10-mo) or dominant-negative ADAM10 (dn-ADAM10) plasmid into the developing chicken spinal cord as well as by in vitro cell culture investigation. Our results show that downregulation of ADAM10 drives precocious differentiation of neural progenitor cells and radial glial cells, resulting in an increase of neurons in the developing spinal cord, even in the prospective ventricular zone. Remarkably, overexpression of the dn-ADAM10 plasmid mutated in the metalloprotease domain (dn-ADAM10-me) mimics the phenotype as found by the ADAM10-mo transfection. Furthermore, in vitro experiments on cultured cells demonstrate that downregulation of ADAM10 decreases the amount of the cleaved intracellular part of Notch1 receptor and its target, and increases the number of βIII-tubulin-positive cells during neural progenitor cell differentiation. Taken together, our data suggest that ADAM10 negatively regulates neuronal differentiation, possibly via its proteolytic effect on the Notch signaling during development of the spinal cord.
PMCID: PMC3880303  PMID: 24404179
20.  Association Study of Serotonin Transporter SLC6A4 Gene with Chinese Han Irritable Bowel Syndrome 
PLoS ONE  2014;9(1):e84414.
Irritable bowel syndrome (IBS) is a common clinical gastrointestinal dysfunction disorders. 5-sertonon (5-hydroxytryptamine, 5-HT) is a very important neurotransmitter, which is involved in gastrointestinal motion and sensation. Solute carrier family 6 member 4 (SLC6A4) gene encode serotonin transporter (SERT) which function is to rapidly reuptake the most of 5-HT. Therefore, it is needed to explore the association between SLC6A4 gene polymorphisms and IBS.
119 patients and 238 healthy controls were administrated to detect the SLC6A4 gene polymorphisms including 5-HT-transporter-gene-linked polymorphic region (5-HTTLPR), variable number of tandem repeats (VNTRs) and three selected tag Single Nucleotide Polymorphisms (SNPs) rs1042173, rs3794808, rs2020936 by using polymerase chain reaction (PCR) and TaqMan® SNP Genotyping.
There were significant difference for 5-HTTLPR between IBS and control groups (X2 = 106.168, P<0.0001). In control group, genotypes were mainly L/L (58.4%), however, the genotypes in IBS were S/S (37.8%). The significant difference was shown in D-IBS subjects when compared to the controls (X2 = 50.850, P<0.0001) for 5-HTTLPR. For STin2 VNTR, rs1042173, rs3794808, and rs2020936 polymorphisms, there were no any significant differences between IBS and control groups. There were no statistical significantly haplotypes for 5-HTTLPR, VNTRs and the three SNPs between IBS and controls.
The S allele in 5-HTTLPR was a susceptible allele with Chinese Han IBS, but other associations of VNTRs, three selected Tag SNPs and positive haplotype with IBS were not found. It is indicated that much research are needed to study the relationship between other polymorphisms in SLC6A4 gene and IBS.
PMCID: PMC3879322  PMID: 24392134
21.  Gender differences of cognitive function in migraine patients: evidence from event-related potentials using the oddball paradigm 
Migraine shows gender-specific incidence and has a higher prevalence in females. Gender plays an important role in the prevalence of migraine, but few studies have investigated the effect of gender on the cognitive functions of migraine patients. This study investigated gender differences in the cognitive function of migraine patients without aura.
We recruited 29 migraine patients (15 females; mean age 25.4 y) during the interictal period and 28 healthy age-matched participants (14 females; mean age 24.8 y). We used an auditory oddball paradigm to analyze target processing using event-related potentials.
We investigated the N2 and P3 components. The P3 amplitude was decreased in patients compared with the control, and this reduction was not modulated by gender. These results of the P3 provided a new evidence for the dysfunction of cognitive function in migraine patients. The N2 amplitude was larger for male than female migraine patients, and this gender effect was not found in the control group.
These results of the P3 provided a new evidence for the dysfunction of cognitive function in migraine patients. And those of N2 may explain that male patients have the super-sensitivity of cerebral function relevant to the early target-selection and response preparation. Our findings emphasize the importance of considering gender when researching the cognitive function of migraine patients.
PMCID: PMC3904684  PMID: 24467625
Migraine; ERPs; P3; N2; Gender difference
22.  Microarray Gene Expression Analysis of Tumorigenesis and Regional Lymph Node Metastasis in Laryngeal Squamous Cell Carcinoma 
PLoS ONE  2013;8(12):e84854.
Laryngeal squamous cell carcinoma (LSCC) is the most common type in head and neck squamous cell carcinoma (HNSCC), and the development and progression of LSCC are multistep processes accompanied by changes of molecular biology.
The purpose of this study was to investigate the molecular basis of tumorigenesis and regional lymph node metastasis in LSCC, and provide a set of genes that may be useful for the development of novel diagnostic markers and/or more effective therapeutic strategies.
A total number of 10 patients who underwent surgery for primary laryngeal squamous cell carcinoma were recruited for microarray analysis. LSCC tissues compared with corresponding adjacent non-neoplastic tissues were analysed by Illumina mRNA microarrays, and LSCC tissues with regional lymph node metastasis and LSCC tissues without regional lymph node metastasis were analyzed in the same manner. The most frequently differently expressed genes screened by microarrays were also validated by qRT-PCR in another 42 patients diagnosed for LSCC.
Analysed by Illumina mRNA microarrays, there were 361 genes significantly related to tumorigenesis while 246 genes significantly related to regional lymph node metastasis in LSCC. We found that the six genes (CDK1, CDK2, CDK4, MCM2, MCM3, MCM4) were most frequently differently expressed functional genes related to tumorigenesis while eIF3a and RPN2 were most frequently differently expressed functional genes related to regional lymph node metastasis in LSCC. The expressions of these genes were also validated by qRT-PCR.
The research revealed a gene expression signature of tumorigenesis and regional lymph node metastasis in laryngeal squamous cell carcinoma. Of the total, the deregulation of several genes (CDK1, CDK2, CDK4, MCM2, MCM3, MCM4, EIF3a and RPN2) were potentially associated with disease development and progression. The result will contribute to the understanding of the molecular basis of LSCC and help to improve diagnosis and treatment.
PMCID: PMC3873425  PMID: 24386425
23.  Two-phase and family-based designs for next-generation sequencing studies 
Frontiers in Genetics  2013;4:276.
The cost of next-generation sequencing is now approaching that of early GWAS panels, but is still out of reach for large epidemiologic studies and the millions of rare variants expected poses challenges for distinguishing causal from non-causal variants. We review two types of designs for sequencing studies: two-phase designs for targeted follow-up of genomewide association studies using unrelated individuals; and family-based designs exploiting co-segregation for prioritizing variants and genes. Two-phase designs subsample subjects for sequencing from a larger case-control study jointly on the basis of their disease and carrier status; the discovered variants are then tested for association in the parent study. The analysis combines the full sequence data from the substudy with the more limited SNP data from the main study. We discuss various methods for selecting this subset of variants and describe the expected yield of true positive associations in the context of an on-going study of second breast cancers following radiotherapy. While the sharing of variants within families means that family-based designs are less efficient for discovery than sequencing unrelated individuals, the ability to exploit co-segregation of variants with disease within families helps distinguish causal from non-causal ones. Furthermore, by enriching for family history, the yield of causal variants can be improved and use of identity-by-descent information improves imputation of genotypes for other family members. We compare the relative efficiency of these designs with those using unrelated individuals for discovering and prioritizing variants or genes for testing association in larger studies. While associations can be tested with single variants, power is low for rare ones. Recent generalizations of burden or kernel tests for gene-level associations to family-based data are appealing. These approaches are illustrated in the context of a family-based study of colorectal cancer.
PMCID: PMC3861783  PMID: 24379824
sequencing; two-phase sampling design; family-based study; rare variant association; breast neoplasms; colorectal cancer
24.  NEXN Is a Novel Susceptibility Gene for Coronary Artery Disease in Han Chinese 
PLoS ONE  2013;8(12):e82135.
Coronary artery disease (CAD) is the leading cause of death and disability in the world. Genome-wide association studies have implicated the importance of the genetic contribution of vascular smooth muscle cells (VSMCs) function in CAD susceptibility. The aberrant phenotypic modulation of VSMC is responsible for the pathological vascular intima hyperplasia that is the hallmark for atherosclerotic morphology. NEXN is a muscle-specific F-actin binding protein and is regulated by inflammatory cytokines in VSMCs. Whether NEXN contributes to human vascular disorders is still unknown. In this study, we genotyped 5 SNPs, tagging all of the 17 common SNPs within 54 kilobases (kb) covering NEXN gene and its flanking region, in 1883 patients with CAD and 1973 healthy individuals from Han Chinese, and identified one SNP, rs1780050, which was strongly associated with CAD trait. The Bonferroni corrected P-value was 7.65×10−5. The odds ratio (95% confidence interval) was 1.23 (1.12–1.36) with statistical power of 0.994. Functional analysis showed that NEXN promotes VSMC to a contractile phenotype in vitro and inhibits balloon-injury induced neointima formation in vivo. Further eQTL analysis demonstrated that the risk allele T of rs1780050 is associated with decreased expression of NEXN, thus contributing to a higher risk of CAD susceptibility in the population. This is, to our knowledge, the first study to identify NEXN as a novel CAD susceptibility gene with both genetic and functional evidence.
PMCID: PMC3859596  PMID: 24349201
25.  Comparison of germination and seed bank dynamics of dimorphic seeds of the cold desert halophyte Suaeda corniculata subsp. mongolica 
Annals of Botany  2012;110(8):1545-1558.
Background and Aims
Differences in dormancy and germination requirements have been documented in heteromorphic seeds of many species, but it is unknown how this difference contributes to maintenance and regeneration of populations. The primary aim of this study was to compare the seed bank dynamics, including dormancy cycling, of the two seed morphs (black and brown) of the cold desert halophyte Suaeda corniculata and, if differences were found, to determine their influence on regeneration of the species.
Seeds of the two seed morphs were buried, exhumed and tested monthly for 24 months over a range of temperatures and salinities, and germination recovery and viability were determined after exposure to salinity and water stress. Seedling emergence and dynamics of the soil seed bank were also investigated for the two morphs.
Key Results
Black seeds had an annual dormancy/non-dormancy cycle, while brown seeds, which were non-dormant at maturity, remained non-dormant. Black seeds also exhibited an annual cycle in sensitivity of germination to salinity. Seedlings derived from black seeds emerged in July and August and those from brown seeds in May. Seedlings were recruited from 2·6 % of the black seeds and from 2·8 % of the brown seeds in the soil, and only 0·5 % and 0·4 % of the total number of black and brown seeds in the soil, respectively, gave rise to seedlings that survived to produce seeds. Salinity and water stress induced dormancy in black seeds and decreased viability of brown seeds. Brown seeds formed only a transient soil seed bank and black seeds a persistent seed bank.
The presence of a dormancy cycle in black but not in brown seeds of S. corniculata and differences in germination requirements of the two morphs cause them to differ in their germination dynamics. The study contributes to our limited knowledge of dormancy cycling and seed bank formation in species producing heteromorphic seeds.
PMCID: PMC3503492  PMID: 22975287
Dormancy; halophyte seeds; salinity; seed germination; seedling recruitment; seed bank dynamics; Suaeda corniculata

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