Shengying Qin

Common variants on 8p12 and 1q24.2 confer risk of schizophrenia

Schizophrenia is a severe mental disorder affecting ∼1% of the world population, with heritability of up to 80%. To identify new common genetic risk factors, we performed a genome-wide association study (GWAS) in the Han Chinese population. The discovery sample set consisted of 3,750 individuals with schizophrenia and 6,468 healthy controls (1,578 cases and 1,592 controls from northern Han Chinese, 1,238 cases and 2,856 controls from central Han Chinese, and 934 cases and 2,020 controls from the southern Han Chinese). We further analyzed the strongest association signals in an additional independent cohort of 4,383 cases and 4,539 controls from the Han Chinese population. Meta-analysis identified common SNPs that associated with schizophrenia with genome-wide significance on 8p12 (rs16887244, P = 1.27 × 10−10) and 1q24.2 (rs10489202, P = 9.50 × 10−9). Our findings provide new insights into the pathogenesis of schizophrenia.

An association study of the N -methyl- D -aspartate receptor NR1 subunit gene ( GRIN1 ) and NR2B subunit gene ( GRIN2B ) in schizophrenia with universal DNA microarray

Dysfunction of the N-methyl-D-aspartate (NMDA) receptors has been implicated in the etiology of schizophrenia based on psychotomimetic properties of several antagonists and on observation of genetic animal models. To conduct association analysis of the NMDA receptors in the Chinese population, we examined 16 reported SNPs across the NMDA receptor NR1 subunit gene (GRIN1) and NR2B subunit gene (GRIN2B), five of which were identified in the Chinese population. In this study, we combined universal DNA microarray and ligase detection reaction (LDR) for the purposes of association analysis, an approach we considered to be highly specific as well as offering a potentially high throughput of SNP genotyping. The association study was performed using 253 Chinese patients with schizophrenia and 140 Chinese control subjects. No significant frequency differences were found in the analysis of the alleles but some were found in the haplotypes of the GRIN2B gene. The interactions between the GRIN1 and GRIN2B genes were evaluated using the multifactor-dimensionality reduction (MDR) method, which showed a significant genetic interaction between the G1001C in the GRIN1 gene and the T4197C and T5988C polymorphisms in the GRIN2B gene. These findings suggest that the combined effects of the polymorphisms in the GRIN1 and GRIN2B genes might be involved in the etiology of schizophrenia.

MiR-140 is co-expressed with Wwp2-C transcript and activated by Sox9 to target Sp1 in maintaining the chondrocyte proliferation

MiR‐140 is a microRNA specially involved in chondrogenesis and osteoarthritis pathogenesis. However, its transcriptional regulation and target genes in cartilage development are not fully understood. Here we detected that miR‐140 was uniquely expressed in chondrocyte and suppressed by Wnt/β‐catenin signalling. The miR‐140 primary transcript was an intron‐retained RNA co‐expressed with Wwp2‐C isoform, which was directly induced by Sox9 through binding to the intron 10 of Wwp2 gene. Knockdown of miR‐140 in limb bud micromass cultures resulted in arrest of chondrogenic proliferation. Sp1, the activator of the cell cycle regulator p15INK4b, was identified as a target of miR‐140 in maintaining the chondrocyte proliferation. Collectively, our findings expand our understanding of the transcriptional regulation and the chondrogenic role of miR‐140 in chondrogenesis.

Polymorphisms of the ABCB1 gene are associated with the therapeutic response to risperidone in Chinese schizophrenia patients

P-glycoprotein, a product of the ATP-binding cassette B1 (ABCB1) gene, plays an important role in absorption and distribution of drugs. The brain entry of risperidone and 9-OH-risperidone is greatly limited by P-glycoprotein, which implies that the functional polymorphisms of ABCB1 in humans may be a factor contributing to the variability in response to risperidone. The present study was therefore designed to examine whether polymorphisms of the ABCB1 gene are related to therapeutic response. For this purpose, 130 Chinese schizophrenia patients undergoing risperidone treatment were recruited. Plasma drug concentrations were monitored and clinical symptoms were evaluated using the Brief Psychiatric Rating Scale (BPRS) before and 8 weeks after the treatment. Association tests between genotypes and percentage improvement in total BPRS scores were performed using analyses of variance. Our results show that genotyping C1236T may help to predict the efficacy of risperidone treatment on the basis that patients with the TT genotype showed greater improvement than those with other genotypes on the overall BPRS (F = 3.967, p = 0.021), while other polymorphisms, including rs13233308, G2677T/A and C3435T polymorphism, did not show any association with the response to risperidone. These results showed suggestive evidence that genetic variation in the ABCB1 gene may influence the individual response to risperidone.

HLA-B*58:01 allele is associated with augmented risk for both mild and severe cutaneous adverse reactions induced by allopurinol in Han Chinese

AIM Allopurinol is widely used as an effective urate-lowering drug and is one of the most frequent causes of cutaneous adverse drug reactions (cADRs). Recently, a strong association of HLA-B*58:01 with allopurinol-induced severe cADRs was identified. This study investigated the predisposition to different types of allopurinol-cADRs conferred by HLA-B*5801 in a Han population from mainland China. PATIENTS & METHODS HLA-B genotyping was performed on 38 Chinese patients with different types of allopurinol-cADRs from 2008 to 2011. RESULTS All the allopurinol-cADR patients carried HLA-B*58:01, in contrast with only 11.11% (7/63) in the allopurinol-tolerant patients (odds ratio [OR] = 580.07; p < 0.0001) and 13.99% (80/572) in a Han Chinese population from the human MHC database (dbMHC; OR: 471.09; p < 0.0001) carried the genotype. Each type of allopurinol cADRs revealed a statistically significant association with HLA-B*58:01. In particular, the risk of allopurinol-induced maculopapular eruption was significantly higher in patients with HLA-B*58:01 (OR: 339.00; p < 0.0001). CONCLUSION The strong association of both the mild and severe types of allopurinol cADRs with the HLA-B*58:01 allele were observed. The results indicated that the prospective use of a genetic test of HLA-B*58:01 might reduce the prevalence of allopurinol-induced cADRs. Original submitted 7 March 2012; Revision submitted 21 May 2012.

Serum prolactin levels, plasma risperidone levels, polymorphism of cytochrome P450 2D6 and clinical response in patients with schizophrenia

The object of this study is to assess 1) the relationship between plasma antipsychotic drug concentration, serum prolactin levels and the clinical efficacy of risperidone, 2) the relationship between the CYP2D6 polymorphisms and metabolizing of risperidone and 3) the role of 9-hydroxyrisperidone in elevating prolactin levels. One-hundred and eighteen Chinese schizophrenia patients (40 males, 78 females, age 15—60 years) were given risperidone at dosages ranging from 2—8 mg/day for 8 weeks. Clinical efficacy was determined using the Brief Psychiatric Rating Scores (BPRS). Serum prolactin levels were assayed before and after the 8 week treatment and plasma risperidone and 9-hydroxyrisperidone levels were also measured at the end of the 8-week treatment. The results showed there was no significant correlation between the concentration of active moiety and clinical response. Risperidone treatment significantly increased serum prolactin levels. Furthermore, changes of prolactin levels were not correlated with the clinical response. For the risperidone/ 9-hydroxyrisperidone ratio, there was a statistically significant difference among the CYP2D6*1/*1, *1/*10, *10/*10 genotypes (Kruskal—Wallis test, p = 0.012). No significant differences were found in the concentration of 9-hydroxyrisperidone and active moiety among the genotypes. In addition, the concentration of 9-hydroxyrisperidone was not significantly correlated with the increase of serum prolactin. In conclusion, our study has, for the first time, produced evidence that in Chinese schizophrenic patients, the metabolism of risperidone is dependent on CYP2D6. Neither changes in serum prolactin levels nor plasma concentration of active moiety were significantly correlated with clinical efficacy of risperidone. 9-hydroxyrisperidone may not play a predominant role in elevating serum prolactin level.

Prediction of Drug-Target Interactions for Drug Repositioning Only Based on Genomic Expression Similarity

Small drug molecules usually bind to multiple protein targets or even unintended off-targets. Such drug promiscuity has often led to unwanted or unexplained drug reactions, resulting in side effects or drug repositioning opportunities. So it is always an important issue in pharmacology to identify potential drug-target interactions (DTI). However, DTI discovery by experiment remains a challenging task, due to high expense of time and resources. Many computational methods are therefore developed to predict DTI with high throughput biological and clinical data. Here, we initiatively demonstrate that the on-target and off-target effects could be characterized by drug-induced in vitro genomic expression changes, e.g. the data in Connectivity Map (CMap). Thus, unknown ligands of a certain target can be found from the compounds showing high gene-expression similarity to the known ligands. Then to clarify the detailed practice of CMap based DTI prediction, we objectively evaluate how well each target is characterized by CMap. The results suggest that (1) some targets are better characterized than others, so the prediction models specific to these well characterized targets would be more accurate and reliable; (2) in some cases, a family of ligands for the same target tend to interact with common off-targets, which may help increase the efficiency of DTI discovery and explain the mechanisms of complicated drug actions. In the present study, CMap expression similarity is proposed as a novel indicator of drug-target interactions. The detailed strategies of improving data quality by decreasing the batch effect and building prediction models are also effectively established. We believe the success in CMap can be further translated into other public and commercial data of genomic expression, thus increasing research productivity towards valid drug repositioning and minimal side effects.

Systematic study of association of four GABAergic genes: Glutamic acid decarboxylase 1 gene, glutamic acid decarboxylase 2 gene, GABAB receptor 1 gene and GABAA receptor subunit β2 gene, with schizophrenia using a universal DNA microarray

Several studies have suggested the dysfunction of the GABAergic system as a risk factor in the pathogenesis of schizophrenia. In the present study, case-control association analysis was conducted in four GABAergic genes: two glutamic acid decarboxylase genes (GAD1 and GAD2), a GABA(A) receptor subunit beta2 gene (GABRB2) and a GABA(B) receptor 1 gene (GABBR1). Using a universal DNA microarray procedure we genotyped a total of 20 SNPs on the above four genes in a study involving 292 patients and 286 controls of Chinese descent. Statistically significant differences were observed in the allelic frequencies of the rs187269C/T polymorphism in the GABRB2 gene (P=0.0450, chi(2)=12.40, OR=1.65) and the -292A/C polymorphism in the GAD1 gene (P=0.0450, chi(2)=14.64 OR=1.77). In addition, using an electrophoretic mobility shift assay (EMSA), we discovered differences in the U251 nuclear protein binding to oligonucleotides representing the -292 SNP on the GAD1 gene, which suggests that the -292C allele has reduced transcription factor binding efficiency compared with the 292A allele. Using the multifactor-dimensionality reduction method (MDR), we found that the interactions among the rs187269C/T polymorphism in the GABRB2 gene, the -243A/G polymorphism in the GAD2 gene and the 27379C/T and 661C/T polymorphisms in the GAD1 gene revealed a significant association with schizophrenia (P<0.001). These findings suggest that the GABRB2 and GAD1 genes alone and the combined effects of the polymorphisms in the four GABAergic system genes may confer susceptibility to the development of schizophrenia in the Chinese population.

The Effect of microRNAs in the Regulation of Human CYP3A4: a Systematic Study using a Mathematical Model

CYP3A4 metabolizes more than 50% of the drugs on the market. The large inter-individual differences of CYP3A4 expression may contribute to the variability of human drug responses. Post-transcriptional regulation of CYP3A4 is poorly understood, whereas transcriptional regulation has been studied much more thoroughly. In this study, we used multiple software programs to predict miRNAs that might bind to CYP3A4 and identified 112 potentially functional miRNAs. Then a luciferase reporter system was used to assess the effect of the overexpression of each potentially functional miRNA in HEK 293T cells. Fourteen miRNAs that significantly decreased reporter activity were measured in human liver samples (N = 27) as candidate miRNAs. To establish a more effective way to analyze in vivo data for miRNA candidates, the relationship between functional miRNA and target mRNA was modeled mathematically. Taking advantage of this model, we found that hsa-miR-577, hsa-miR-1, hsa-miR-532-3p and hsa-miR-627 could significantly downregulate the translation efficiency of CYP3A4 mRNA in liver. This study used in silico, in vitro and in vivo methods to progressively screen functional miRNAs for CYP3A4 and to enhance our understanding of molecular events underlying the large inter-individual differences of CYP3A4 expression in human populations.

Intra-ethnic differences in genetic variants of the UGT-glucuronosyltransferase 1A1 gene in Chinese populations.

Variants within the human UGT1A1 gene are associated with irinotecan induced severely adverse reactions and hyperbilirubinemia. Intra-ethnic differences in the genetic variation and haplotypes of UGT1A1 gene have been analyzed in the present study. Relationship between the concentrations of total serum bilirubin (T-bil) and haplotype structure of UGT1A1 in healthy people were also evaluated. We genotyped five functional polymorphisms including −3279T>G and −3156G>A in the enhancer region, (TA)6>7 in the TATA box, and 211G>A (G71R), 686C>A (P229Q) in the exon1 region of UGT1A1 in three groups of healthy Chinese ethnic populations, consisting of 264 subjects of She origin, 539 of Han origin and 273 of Dong origin. The distribution of −3279T>G, (TA)6>7, 211G>A of UGT1A1 differed greatly as between the three ethnic groups. All of six haplotypes differed considerably between at least two of the three groups, which highlighted the need to analyze clinically irinotecan toxicity relevant SNPs and haplotypes in a variety of different racial groups within the Chinese population. Total bilirubin concentration in homozygous carriers of the −3279G and (TA)7 allele were significantly higher than those in heterozygous carriers or homozygous carriers of wild-type alleles. Carriers of the variant haplotypes (−3279G; −3156A; (TA)7; 211G; 686C) had higher serum T-Bil concentrations compared with the other groups. Our results indicate that heterogeneity among different ethnic populations is possibly the result of microevolution and is relevant to studies into the effect of tailored drug treatment.