Shuzheng Liu

Cytosolic PLA2 genes possibly contribute to the etiology of schizophrenia.

The present study detected three single nucleotide polymorphisms (SNPs), BanISNP at the PLA2G4A locus, rs1648833 at the PLA2G4B locus, and rs1549637 at the PLA2G4C locus, to investigate a genetic association between the cytosolic PLA2 (cPLA2) genes and schizophrenia. A total of 240 Chinese parent–offspring trios of Han descent were recruited for the genetic analysis. The transmission disequilibrium test (TDT) showed allelic association for rs1549637 (χ2 = 5.68, uncorrected P = 0.017), but not for BanISNP and rs1648833. The conditioning on genotype (COG) test revealed a disease association for the BanISNP–rs1648833 combination (χ2 = 12.54, df = 3, P = 0.0057) and for the BanISNP–rs1549637 combination (χ2 = 9.72, df = 2, P = 0.021), but the conditioning on allele (COA) test did not show such an association for the above two combinations. Neither the COA test nor the COG showed a disease association for the rs1648833–rs1549637 combination. In the combination of all three SNPs, the COG test, but not the COA test, showed a strong association (χ2 = 22.93, df = 6, P = 0.0008). These findings suggest that these three cPLA2 genes may all be involved in contributing to the etiology of schizophrenia although their effect size appears to be relatively small.

Whole-Body Low Dose Irradiation Promotes the Efficacy of Conventional Radiotherapy for Cancer and Possible Mechanisms

The purpose of the present study was to explore the possibility of establishing cancer radiotherapy protocols that could promote treatment efficacy at a reduced radiation dose. Mouse models of melanoma (B16) and Lewis lung carcinoma (LLC) were used in the experiments. Conventional local radiotherapy was combined with low dose whole-body irradiation (LDWBI) in the presence or absence of gene therapy by intratumor injection of a recombinant plasmid Egr-mIL-18-B7.1 (E18B). After a number of trials with different combinations it was found that a protocol of 2-week treatment with 2 × (E18B + 2 Gy + 0.075 Gy × 2) was found to be able to promote treatment efficacy at a reduced radiation dose. In this protocol local irradiation with 2Gy was administered 24h after intratumor injection of 10 μg of the plasmid E18B followed by LDWBI with 0.075 Gy every other day for 2 sessions in 1 week, and the procedure was repeated for another week. When this combined treatment was compared with conventional radiotherapy, i.e., 2Gy every other day 3 times in one week repeated for 2 weeks, the treatment efficacy was improved, as judged by increased average survival rate, reduced mean tumor weight, reduced pulmonary metastasis and suppressed intratumor capillary growth with a 2/3 reduction of radiation dose. Immunologic studies showed stimulated natural killer (NK) and cytotoxic T lymphocyte (CTL) activity as well as increased interferon-γ (IFN-γ) secretion in this combined treatment group as compared with the group receiving local treatment alone. It is suggested that up-regulation of host anticancer immunity by LDWBI and the initiation of expression of immune genes by both the local large dose and LDWBI are important factors in the realization of improved cancer control.

A review and Re-evaluation of an association between the NOTCH4 locus and schizophrenia

This work reviewed all the reports on the NOTCH4 gene in schizophrenia, which have been published since the gene was found to be associated with illness among a British population in 2000. The results from independent studies were inconsistent. Allelic heterogeneity, clinical diagnosis, ethnical backgrounds, and linkage disequilibrium (LD) structures in the human genome may be major reasons for poor replication. A couple of studies suggested that the NOTCH4 gene could play a role in a subgroup of the disease, such as early‐onset schizophrenia and negative symptoms. A single study revealed a weak association of the NOTCH4 gene with frontal lobe brain volumes and a strong association with frontal lobe cognitive performance. A meta‐analysis showed stronger evidence of the NOTCH4 association in family‐based studies than in case‐control studies. In a previous study, we found that rs520692, a single nucleotide polymorphism (SNP) at the NOTCH4 locus, was associated with schizophrenia in a Chinese population. In the present study, we applied a large sample size to re‐evaluate our initial findings and then confirmed the rs520692 association with illness. The pairwise measures did not show strong LD between paired SNPs although the SNPs tested are located within a 34‐kb region, suggesting that LD within the NOTCH4 gene has been broken rapidly by historical recombination in the Chinese population. Taken together, the NOTCH4 gene may be associated with schizophrenia but how the gene contributes to the etiology of the illness needs a further investigation.

Is NOTCH4 associated with schizophrenia

The NOTCH4 locus was reported to be associated with schizophrenia in our previous study but the subsequent replication by other workers has been inconsistent. To find out possible reasons for the poor replication, the present work was undertaken to analyse four functional single nucleotide polymorphisms (SNPs) (rs367398, rs915894, rs520692 and rs422951) at the NOTCH4 locus among 141 schizophrenic family trios of Chinese Han descent. Of these four SNPs, rs520692 was the only one associated with schizophrenia (P=0.017); the other three, however, did not show any association with the illness, including rs367398 located in the promoter region, which had shown a strong association with the illness in our previous study conducted with British samples. Although these four SNPs analysed lie within a less than 4 kb segment of genomic DNA, the pattern of linkage disequilibrium between them was unexpected. The strongest linkage disequilibrium was shown only between rs367398 and rs520692 and between rs520692 and rs422951 in both parent and patient groups. This study raises the possibility that there might be two or more disease-underlying variants at the NOTCH4 locus or at a nearby locus, and that the allelic or locus heterogeneity may be one of the possible reasons for the poor replication of the NOTCH4 finding.

A study of the PEMT gene in schizophrenia

The phospholipid hypothesis of schizophrenia is becoming popular because of the findings from the niacin flush test, the treatment with polyunsaturated fatty acids (PUFAs), biochemical studies for the phospholipid metabolism pathway and genetic studies of phospholipase A2. The present study attempted to investigate the gene coding for phosphatidylethanolamine N-methyltransferase (PEMT), which is an important enzyme for the synthesis of membrane phospholipids. We recruited 271 Chinese parent-offspring trios of Han descent and detected 3 single nucleotide polymorphisms (SNPs) at the PEMT locus. The transmission disequilibrium test (TDT) showed allelic association for rs464396 (X2=9.4, P=0.002), but not for the other two. The 2-SNP haplotype analysis showed haplotypic association for both the rs936108-rs464396 haplotypes (X2=25.7, d.f.=3, P=0.00001) and the rs464396-rs4244593 haplotypes (X2=17.3, d.f.=3, P=0.0006). The 3-SNP haplotype analysis also showed a haplotypic association (X2=24.4, d.f.=7, P=0.0006). The present results suggest that the PEMT gene may contribute to the etiology of schizophrenia.

Association of six polymorphisms of the NOTCH4 gene with schizophrenia in the Japanese population.

The NOTCH4 gene is located at 6p21.3 and involved in the development and patterning of the central nervous systems. Recently, Wei and Hemmings [ 2000 ] observed that the gene was associated with schizophrenia. Subsequent to the report, several studies investigated the gene in schizophrenia, with controversial and inconclusive results. In the present study, we investigated six polymorphisms (SNPs 1–5 and a CTG repeat) of the gene in Japanese subjects with schizophrenia (n = 284) and the same number of controls. The polymorphisms include SNP5, which has been observed to be associated with schizophrenia in a Chinese population and two new SNPs 3–4 adjacent to SNP5, in addition to the SNPs 1–2 and the CTG repeat, which were suggested for the association with the disease in the previous study. As a result, no significant difference in genotypic distributions or allelic frequencies of the six polymorphisms of the gene was observed between the patients and the controls. Also, no significant difference was found in frequencies of haplotypes of the six polymorphisms between the patients and the controls. However, the distribution of SNP2 was significantly deviated from Hardy–Weinberg equilibrium in the patients (P = 0.000986), not in the controls, which could be a chance or due to an association of SNP2 with the disease. In conclusion, the present study provided no clear evidence for an association between the NOTCH4 gene and schizophrenia in the Japanese population.

A combined effect of the KPNA3 and KPNB3 genes on susceptibility to schizophrenia

Recent studies suggest that both the KPNB3 gene and the KPNA3 gene in the long arm of chromosome 13 (13q) are associated with schizophrenia. Because these two genes belong to the same family of karyopherins, their combined effect on illness was investigated among 238 Chinese family trios consisting of fathers, mothers and affected offspring with schizophrenia. We detected three single nucleotide polymorphisms (SNPs), including rs626716 at the KPNB3 locus, and rs3782929 and rs3736830 at the KPNA3 locus. The transmission disequilibrium test (TDT) showed allelic association for rs626716 (X2=10.77, P=0.001) and for rs3782929 (X2=4.89, P=0.027) but not for rs3736830 (X2=0.29, P=0.59). Although the conditional test did not show association either for the rs626716-rs3782929 combinations (X2=1.329, d.f.=2, P=0.514) or for the rs626716-rs3736830 combinations (X2=0.606, d.f.=2, P=0.739), the 1-d.f. test showed association for the rs626716(C)-rs3782929(G) combination (X2=10.79, P=0.001) and for the rs626716(C)-rs3736830(G) combination (X2=8.64, P=0.003). The present work suggests that the combination of the KPNA3 gene and the KPNB3 gene may increase a genetic risk for schizophrenia.

Increase in efficacy of cancer radiotherapy by combination with whole-body low dose irradiation

Purpose:Design of cancer radiotherapy protocol to reduce radiation dose and increase treatment efficacy in Lewis lung cancer (LLC) model. Methods: C57BL/6J mice subcutaneously implanted with LLC were treated by conventional radiotherapy (2Gy × 6) combined with LDWBI (low dose whole-body irradiation; the second, third, fifth and sixth local doses of 2Gy each substituted by LDWBI with 0.075Gy) and/or gene therapy (intratumor injection of pEgr-IL-18-B7.1 plasmid 24 h before the first and fourth local doses). Immunologic mechanisms were explored. Results: Cancer control was most significantly improved in the group receiving local radiotherapy combined with LDWBI and gene therapy as shown by prolongation of mean survival time by 60.4%, reduction in average tumor weight by 70.8%, decrease in pulmonary metastasis by 66.9% and decrease in intratumor angiogenesis by 64.8% as compared to local radiotherapy alone (p < 0.05). These changes in tumor growth and progression were accompanied with up-regulation of host immunity manifested by stimulated NK (natural killer) and CTL (cytotoxic T lymphocyte) activity, IFN (interferon)-gamma and TNF (tumor necrosis factor)-alpha secretion, PKC (protein kinase C)-theta activation and LAMP (lysosomal associated membrane protein)-1 expression. Conclusion: Combination of conventional radiotherapy with LDWBI and gene transfer could reduce total radiation dose by 2/3 and at the same time improve treatment efficacy of cancer accompanied with up-regulated host anticancer immunity.

Lack of a genetic association between the TNXB locus and schizophrenia in a Chinese population

A recent study demonstrated that the tenascin X (TNXB) gene was associated with schizophrenia in a British population. To replicate the initial finding, we analysed two positive single nucleotide polymorphisms (SNPs), rs1009382 and rs204887 present at the TNXB locus, in a Chinese population by using PCR-based restriction fragment length polymorphism analysis. We recruited a total of 136 family trios consisting of fathers, mothers and affected offspring with schizophrenia. The transmission disequilibrium test did not show allelic association between these two SNPs and schizophrenia, and the rs1009382-rs204887 haplotypes were not associated with the illness either. The present results suggest that the TNXB locus does not appear to be associated with schizophrenia in the Chinese population. Because the TNXB gene is less than 100 kb away from the NOTCH4 locus that was also reported to be associated with schizophrenia, allelic and locus heterogeneity could be possible reasons for the failure to replicate the TNXB finding.

A Family-and Population-Based Study of the UFD1L Gene for Schizophrenia

The present work was undertaken to investigate the association of the UFD1L locus with schizophrenia among 304 Chinese family trios of Han descent. We detected four single nucleotide polymorphisms (SNPs) in the 5′‐end region of the UFD1L gene. The transmission disequilibrium test (TDT) revealed allelic associations for rs5746744 (χ2 = 8.02, P = 0.005) and rs1547931 (χ2 = 7.18, P = 0.007), but failed to replicate disease association for rs5992403 present in the promoter region, which was initially found in Italian and Canadian samples. The allelic association for rs5746744 and rs1547931 was replicated with independently recruited case–control samples. The 2‐SNP haplotype analysis showed an association for the rs5992403‐rs5746744 haplotypes (χ2 = 18.92, df = 3, P = 0.0003), the rs5746744‐rs1547931 haplotypes (χ2 = 11.06, df = 3, P = 0.011) and the rs1547931‐rs2238769 haplotypes (χ2 = 18.88, df = 3, P = 0.0003). The 4‐SNP haplotype analysis also showed strong association with illness (χ2 = 29.54, df = 9, P = 0.0005) but there were more than one individual haplotypes with a low frequency excessively non‐transmitted. The four SNPs tested were not located in the same LD block among the Chinese population. This study raises the possibility that a disease‐resistant variant may be carried by two or more haplotypes at the UFD1L locus due to frequent recombination during meiosis.