Xingyi Yang

Investigation of the performance of PEG-PEI/ROCK-II-siRNA complexes for Alzheimer's disease in vitro.

Recent studies have showed inhibiting ROCK promoted axonal regeneration and suppressing ROCK-II decreased Aβ formation, suggesting ROCK is a potential target for the treatment of Alzheimers disease. Because ROCK-II mRNA is abundantly expressed in brain, we targeted ROCK-II mRNA using a siRNA approach. To suppress ROCK-II mRNA expression, we synthesized PEG-PEI/ROCK-II-siRNA complexes and transfected C17.2 neural stem cells in vitro. The characteristics of the complexes were tested using a gel retardation assay. Particle size and zeta potential were examined using dynamic light scattering and the morphology of the complexes were observed by transmission electron microscopy. The toxicity was detected by an MTT assay and transfection efficiency was determined by flow cytometry. Laser confocal microscopy was employed to investigate the cell uptake of the complexes. RT-PCR and western blotting were used to verify the effect of gene silencing. Our results indicated that the characteristics of the complexes depended on the N/P ratios. At a high N/P ratio, PEG-PEI could completely condense the siRNA into small-sized uniform particles. However, high N/P ratios are accompanied with high cytotoxicity. Because of high transfection efficiency and low cytotoxicity, N/P=50 was chosen to transfect C17.2 cells in vitro. Laser confocal microscopy showed that ROCK-II-siRNA with green fluorescence was mainly distributed in the cytoplasm and synapses. Moreover, ROCK-II-siRNA was successfully released from the lysosome. RT-PCR and western blotting demonstrated effective gene silencing. These results indicated that PEG-PEI/ROCK-II-siRNA complexes effectively suppressed ROCK-II mRNA expression, providing the basis for future research in vivo.

Characterization of Polyethylene Glycol‐Polyethyleneimine as a Vector for Alpha‐Synuclein siRNA Delivery to PC12 Cells for Parkinson's Disease

Gene therapy targeting the SNCA gene yields promising results in the treatment of Parkinsons disease (PD). The most challenging issue of the RNAi gene therapy strategy is maintaining efficient delivery without inducing significant toxicity and other adverse effects. This study aimed to characterize polyethylene glycol‐polyethyleneimine as a vector for alpha‐synuclein siRNA delivery to PC12 cells for Parkinsons disease.

Protective effect of alpha-synuclein knockdown on methamphetamine-induced neurotoxicity in dopaminergic neurons

The over-expression of α-synuclein is a major factor in the death of dopaminergic neurons in a methamphetamine-induced model of Parkinsons disease. In the present study, α-synuclein knockdown rats were created by injecting α-synuclein-shRNA lentivirus stereotaxically into the right striatum of experimental rats. At 2 weeks post-injection, the rats were injected intraperitoneally with methamphetamine to establish the model of Parkinsons disease. Expression of α-synuclein mRNA and protein in the right striatum of the injected rats was significantly downregulated. Food intake and body weight were greater in α-synuclein knockdown rats, and water intake and stereotyped behavior score were lower than in model rats. Striatal dopamine and tyrosine hydroxylase levels were significantly elevated in α-synuclein knockdown rats. Moreover, superoxide dismutase activity was greater in α-synuclein knockdown rat striatum, but the levels of reactive oxygen species, malondialdehyde, nitric oxide synthase and nitrogen monoxide were lower compared with model rats. We also found that α-synuclein knockdown inhibited methamphetamine-induced neuronal apoptosis. These results suggest that α-synuclein has the capacity to reverse methamphetamine-induced apoptosis of dopaminergic neurons in the rat striatum by inhibiting oxidative stress and improving dopaminergic system function.

Development of the 19 X-STR loci multiplex system and genetic analysis of a Zhejiang Han population in China

The 19 X‐STRs multiplex system is a PCR‐based amplification kit that facilitates simultaneous amplification of 19 X‐chromosomal STR loci (i.e. DXS7423, DXS10148, DXS10159, DXS6809, DXS7424, DXS8378, DXS10164, DXS10162, DXS7132, DXS10079, DXS6789, DXS101, DXS10103,DXS10101, HPTRB, DXS10075, DXS10074, DXS10135, and DXS10134). Eleven loci were extensively used in an Investigator Qiagen Argus X‐12 (DXS7423, DXS10148, DXS8378, DXS10162, DXS7132, DXS10079, DXS10103, DXS10101, HPTRB, DXS10074, and DXS10135). In this research, the multiplex system was tested for detection sensitivity, DNA mixtures, inhibitor tolerance and species specificity; SWGDAM Validation Guidelines – Approved December 2012 were followed for the human fluorescent STR multiplex PCR reagent. Samples from 181 unrelated Zhejiang Han individuals (121 males and 60 females) were typed using this multiplex system. The results show that this 19X‐STRs multiplex system is a robust and reliable amplification means to facilitate forensic and human identification testing.

Polymorphism analysis of 15 STR loci in a large sample of Guangdong (Southern China) Han population

AmpFℓSTR Sinofiler PCR Amplification Kit is specially developed for Chinese forensic laboratories, but there are little population-genetic data about this kit for Southern China. This kit contains 15 STR loci: D8S1179, D21S11, D7S820, CSF1PO, D3S1358, D13S317, D16S539, D2S1338, D19S433, vWA, D18S51, D6S1043, D12S391, D5S818 and FGA. We have conducted genotyping experiments on the 15 STR loci in 5234 unrelated individuals from Guangdong (Southern China). We observed a total of 243 alleles in the group with the allelic frequency values ranging from less than 0.0001 to 0.3686. Our statistic analysis indicates that the 15 STR loci conform to the Hardy-Weinbergs equilibrium (p>0.05). The highest polymorphism was found at D6S1043 locus and the lowest was found at D3S1358. The combined power of discrimination reached 0.99999999999999999977431 and the combined probability of paternity exclusion reached 0.999999721 for 15 STR loci. Guangdong Han population had significant differences compared with Shaanxi, Shandong and Henan province of Northern China. A Neighbor-joining tree indicates that the Guangdong Han has a close genetic relationship with the Yunnan population. Significant differences were found between Guangdong Han population and other reported populations (Japanese, Philippine, African American, Caucasian, Hispanic and Western Romanian) at 2-11 STR loci. The results may provide useful information for forensic sciences and population genetics studies. The present findings indicate that all the 15 STR loci are highly genetically polymorphic in the Han population of Guangdong.

Genetic analysis of 19 X chromosome STR loci for forensic purposes in four Chinese ethnic groups.

A new 19 X- short tandem repeat (STR) multiplex PCR system has recently been developed, though its applicability in forensic studies has not been thoroughly assessed. In this study, 932 unrelated individuals from four Chinese ethnic groups (Han, Tibet, Uighur and Hui) were successfully genotyped using this new multiplex PCR system. Our results showed significant linkage disequilibrium between markers DXS10103 and DXS10101 in all four ethnic groups; markers DXS10159 and DXS10162, DXS6809 and DXS6789, and HPRTB and DXS10101 in Tibetan populations; and markers DXS10074 and DXS10075 in Uighur populations. The combined powers of discrimination in males and females were calculated according to haplotype frequencies from allele distributions rather than haplotype counts in the relevant population and were high in four ethnic groups. The cumulative powers of discrimination of the tested X-STR loci were 1.000000000000000 and 0.999999999997940 in females and males, respectively. All 19 X-STR loci are highly polymorphic. The highest Reynolds genetic distances were observed for the Tibet-Uighur pairwise comparisons. This study represents an extensive report on X-STR marker variation in minor Chinese populations and a comprehensive analysis of the diversity of these 19 X STR markers in four Chinese ethnic groups.

Inhibition of ROCK2 expression protects against methamphetamine-induced neurotoxicity in PC12 cells.

Methamphetamine is a type of psychoactive drug. It is well known that neurotoxicity caused by Methamphetamine(METH) can damage the nervous system and lead to apoptosis and cell loss of dopaminergic neurons. ROCK2 is a prominent target for gene therapy because its inhibition has proved to have a protective effect in various cell lines and pathophysiological conditions. Although several of the negative effects of METH on the dopaminergic system have been studied, the protective molecular mechanisms and the effective treatment of METH-induced apoptosis remain to be clarified. We hypothesized that ROCK2 is involved in METH-induced apoptosis. We tested our hypothesis using RT-PCR and western blotting to analyze whether silencing of ROCK2 with small interfering RNA (siROCK2) could reduce damage and apoptosis in PC12 cells after METH exposure. Increases in viability and cytomorphological changes were detected by MTT assay and bright field microscopy after pretreatment of METH-treated PC12 cells with 100 nM siROCK2. Apoptosis decreased significantly after ROCK2 silencing, as shown by Annexin V and TUNEL staining. The results show that ROCK2 is a possible gene target for therapeutics in METH-induced neurotoxicity in vitro, providing a foundation for future in vivo research.

Haplotype analysis of the polymorphic 24 Y-STR markers in six ethnic populations from China

Abstract Twenty-four Y-STR loci were analysed in 1446 males from the following six Chinese ethnic populations: Guangxi Han (n=600), Gin (n=161), Maonan (n=135), Miao (n=186), Zhuang (n=226) and Yao (n=138) using the AGCU Y24 STR amplification kit. The lowest estimates of genetic diversity (below 0.5) correspond to markers DYS391 (0.4006), DYS438 (0.4300), and DS388 (0.4907), and the greatest diversity corresponds to markers DYS385a/b (0.9636) and DYS527a/b (0.9439). Moreover, there were 1331 different haplotypes identified from the 1446 total samples, of which 1233 were unique. Notably, we observed shared haplotypes between the four ethnic populations (Maonan, Miao, Zhuang, Yao ethnic population), except between the Guangxi Han and Gin population. The estimated overall haplotype diversity (HD) was 0.9997. A multidimensional scaling (MDS) plot based on the genetic distances between populations demonstrates the genetic similarity of the Maonan, Miao and Zhuang populations with genetic distance below 3.0. No substructure correction is required to estimate the rarity of a haplotype comprising 24 markers. In summary, the results of our study indicate that the 24 Y-STRs have a high level of polymorphism in these six Chinese ethnic populations and could therefore be a powerful tool for forensic applications and population genetic studies.

Genetic polymorphism analysis of 40 Y-chromosomal STR loci in seven populations from South China

China is a multi-ethnic country. Due to its diverse terrain, many ethnic groups are geographically isolated within China. This phenomenon is especially prevalent in southern China. As Y-STR loci are paternally inherited, they can be used to effectively understand the genetic relationship between different populations and thus aid in forensic science. In this study, forty Y-STR loci were analysed in 2018 unrelated male individuals from the following seven ethnic populations in South China: Yao (n=147), Zhuang (n=225), Gelao (n=156), Miao (n=186), Maonan (n=133), Gin (n=160) and Guangxi Han (n=1011). Using both AGCU Y24 STR and GFS Y24 STR genotyping kits, a total of 335 alleles and 141 haplotypes of three multi-copy loci were observed in these seven populations. The highest GD value of the 40 Y-STR loci in the overall population was 0.9643 for DYS385a/b, while the lowest was 0.4101 for DYS438. Out of the 2018 samples analysed, 1935 distinct haplotypes and 1858 unique haplotypes were observed. The HD value of the total samples was up to 0.9994 and ranged from a low of 0.9908 in the Yao to a high of 0.9999 in the Han population. We found using population structure analysis that the genetic distance is smaller among the seven southern populations (Guangxi Han, Gelao, Yao, Miao, Zhuang, Jing and Maonan) than the northern populations (Tibetan, Korean, Mongolian, Uygur and Hui). We show that the 40 Y-STRs have a high level of polymorphism in the South China ethnic groups and there is a high degree of differentiation among ethnic groups located in geographically distributed and densely populated areas. These data may provide additional resources for forensic applications and population genetic studies.

A finding in genetic polymorphism analysis study: A case of non-mosaic 47, XXX without manifestations

Trisomy X (47, XXX) is a sex chromosome aneuploidy condition in which females have an extra X chromosome, compared to the 46, XX karyotype in typical females. There is considerable variation in the phenotype, with some individuals very mildly affected and others with more significant physical and psychological features. However, the trisomy X in this case, without any of these phenotype, is rarely reported. Here, we report a case found during DNA sample collection in a study of genetic polymorphism analysis of loci in Chinese ethnic group, of a female with neither laboratory or clinical signs of Triple X syndrome. She was born at her mothers 60years old and her fathers 62years old. Advanced maternal age was found acting as a significant risk factor of Triplo-X. Moreover, her child are also born without manifestations of 47, XXX syndrome. Pedigree study demonstrated the normal karyotype of the children. A diagnosis of 47XXX was made on the basis of a chromosomal study. Therefore, laboratory investigations (including PCR amplification, more than two kinds of X-STR genotyping, G-banding karyotyping analysis and Pedigree study) are applied to rule out the possibility of Mosaicism (45, X0/47, XXX) and ascertain her 47XXX karyotype without mosaic. The objective of this study was to report a case of trisomy X, diagnostic investigation and management of the case, and to analysis the genetically possible reasons behind the case. To our knowledge, this case is a rare one, found in DNA sample collection for the estimation of gene frequency in the process of genetic polymorphism study, of non-mosaic 47, XXX without signs of physical syndrome and born healthy children. In this study, it revealed that the proportion of trisomy X would be more than official statistics and risk of systemic disabilities is lower than estimated. Moreover, we found out that sample mixture and mosaicism act as the interference factors in forensic test. Therefore, we draw the conclusion that attentions and certain improved methods should be applied to the diagnosis of non-mosaic triple X, which is of great significance in decreasing the interruptions in the whole process of forensic and paternity identification.