Yaran Yang

Long-term cultured mesenchymal stem cells frequently develop genomic mutations but do not undergo malignant transformation

Cultured human umbilical cord mesenchymal stem cells (hUC-MSCs) are being tested in several clinical trials and encouraging outcomes have been observed. To determine whether in vitro expansion influences the genomic stability of hUC-MSCs, we maintained nine hUC-MSC clones in long-term culture and comparatively analyzed them at early and late passages. All of the clones senesced in culture, exhibiting decreased telomerase activity and shortened telomeres. Two clones showed no DNA copy number variations (CNVs) at passage 30 (P30). Seven clones had ≥1 CNVs at P30 compared with P3, and one of these clones appeared trisomic chromosome 10 at the late passage. No tumor developed in immunodeficient mice injected with hUC-MSCs, regardless of whether the cells had CNVs at the late passage. mRNA-Seq analysis indicated that pathways of cell cycle control and DNA damage response were downregulated during in vitro culture in hUC-MSC clones that showed genomic instability, but the same pathways were upregulated in the clones with good genomic stability. These results demonstrated that hUC-MSCs can be cultured for many passages and attain a large number of cells, but most of the cultured hUC-MSCs develop genomic alterations. Although hUC-MSCs with genomic alterations do not undergo malignant transformation, periodic genomic monitoring and donor management focusing on genomic stability are recommended before these cells are used for clinical applications.

Application of Next-generation Sequencing Technology in Forensic Science

Next-generation sequencing (NGS) technology, with its high-throughput capacity and low cost, has developed rapidly in recent years and become an important analytical tool for many genomics researchers. New opportunities in the research domain of the forensic studies emerge by harnessing the power of NGS technology, which can be applied to simultaneously analyzing multiple loci of forensic interest in different genetic contexts, such as autosomes, mitochondrial and sex chromosomes. Furthermore, NGS technology can also have potential applications in many other aspects of research. These include DNA database construction, ancestry and phenotypic inference, monozygotic twin studies, body fluid and species identification, and forensic animal, plant and microbiological analyses. Here we review the application of NGS technology in the field of forensic science with the aim of providing a reference for future forensics studies and practice.

Screening and characterization of butanol-tolerant micro-organisms

Aims:  Poor butanol tolerance of solventogenic stains directly limits their butanol production during industrial‐scale fermentation process. This study was performed to search for micro‐organisms possessing elevated tolerance to butanol.

A novel strategy for forensic age prediction by DNA methylation and support vector regression model

High deviations resulting from prediction model, gender and population difference have limited age estimation application of DNA methylation markers. Here we identified 2,957 novel age-associated DNA methylation sites (P < 0.01 and R2 > 0.5) in blood of eight pairs of Chinese Han female monozygotic twins. Among them, nine novel sites (false discovery rate < 0.01), along with three other reported sites, were further validated in 49 unrelated female volunteers with ages of 20–80 years by Sequenom Massarray. A total of 95 CpGs were covered in the PCR products and 11 of them were built the age prediction models. After comparing four different models including, multivariate linear regression, multivariate nonlinear regression, back propagation neural network and support vector regression, SVR was identified as the most robust model with the least mean absolute deviation from real chronological age (2.8 years) and an average accuracy of 4.7 years predicted by only six loci from the 11 loci, as well as an less cross-validated error compared with linear regression model. Our novel strategy provides an accurate measurement that is highly useful in estimating the individual age in forensic practice as well as in tracking the aging process in other related applications.

Transcriptome dynamics during human erythroid differentiation and development

To explore the mechanisms controlling erythroid differentiation and development, we analyzed the genome-wide transcription dynamics occurring during the differentiation of human embryonic stem cells (HESCs) into the erythroid lineage and development of embryonic to adult erythropoiesis using high throughput sequencing technology. HESCs and erythroid cells at three developmental stages: ESER (embryonic), FLER (fetal), and PBER (adult) were analyzed. Our findings revealed that the number of expressed genes decreased during differentiation, whereas the total expression intensity increased. At each of the three transitions (HESCs-ESERs, ESERs-FLERs, and FLERs-PBERs), many differentially expressed genes were observed, which were involved in maintaining pluripotency, early erythroid specification, rapid cell growth, and cell-cell adhesion and interaction. We also discovered dynamic networks and their central nodes in each transition. Our study provides a fundamental basis for further investigation of erythroid differentiation and development, and has implications in using ESERs for transfusion product in clinical settings.

Comprehensive characterization of erythroid-specific enhancers in the genomic regions of human Krüppel-like factors

BackgroundMapping of DNase I hypersensitive sites (DHSs) is a powerful tool to experimentally identify cis-regulatory elements (CREs). Among CREs, enhancers are abundant and predominantly act in driving cell-specific gene expression. Krüppel-like factors (KLFs) are a family of eukaryotic transcription factors. Several KLFs have been demonstrated to play important roles in hematopoiesis. However, transcriptional regulation of KLFs via CREs, particularly enhancers, in erythroid cells has been poorly understood.ResultsIn this study, 23 erythroid-specific or putative erythroid-specific DHSs were identified by DNase-seq in the genomic regions of 17 human KLFs, and their enhancer activities were evaluated using dual-luciferase reporter (DLR) assay. Of the 23 erythroid-specific DHSs, the enhancer activities of 15 DHSs were comparable to that of the classical enhancer HS2 in driving minimal promoter (minP). Fifteen DHSs, some overlapping those that increased minP activities, acted as enhancers when driving the corresponding KLF promoters (KLF-Ps) in erythroid cells; of these, 10 DHSs were finally characterized as erythroid-specific KLF enhancers. These 10 erythroid-specific KLF enhancers were further confirmed using chromatin immunoprecipitation coupled to sequencing (ChIP-seq) data-based bioinformatic and biochemical analyses.ConclusionOur present findings provide a feasible strategy to extensively identify gene- and cell-specific enhancers from DHSs obtained by high-throughput sequencing, which will help reveal the transcriptional regulation and biological functions of genes in some specific cells.

Whole transcriptome RNA-seq analysis: tumorigenesis and metastasis of melanoma

Melanoma is the most malignant cutaneous cancer and causes over 9000 deaths annually. Because fatality rates from malignant melanoma (MM) increase dramatically upon metastasis, we investigated tumorigenesis and metastasis of MM in transcriptome analyses of three distinct cell lines that correspond with the stages of MM pathogenesis: the normal stage (HEMn-LP), the onset of MM (A375), and the metastasis stage (A2058). Using next-generation sequencing (NGS) technology, we detected asymmetrical expression of genes among the three cell lines, notably on chromosomes 9, 11, 12, and 14, suggesting their involvement in tumorigenesis and metastasis of MM. These genes were clustered into 41 categories based on their expression patterns, and their biological functions were analyzed using Ingenuity Pathway Analysis. In the top cancer-associated category, HIF1A, IL8, TERT, ONECUT1, and FOXA1 directly interacted with either transcription factors or cytokines that are known to be involved in the tumorigenesis or metastasis of other malignant tumors. The present data suggest that cytokine regulatory pathways in macrophages predominate over other pathways during the pathogenesis of MM. This study provides new targets for the downstream mechanistic studies of the tumorigenesis and metastasis of MM and demonstrates a new strategy for studies of the progression of other malignant cancers.

Genetic distribution of 39 STR loci in 1027 unrelated Han individuals from Northern China

The Han Ethnic Group is the largest among the 56 ethnic groups in China, accounting for 92% of the total population. The Han people are found in all parts of the country. One study showed that the Han Chinese population was actually substructured in a complex manner, with the main observed clusters roughly corresponding to the Northern-Han, Central-Han, and SouthernHan populations [1]. In the present study, population genetic data and forensic parameters of 39 autosomal short tandem repeats (STRs) were obtained from 1027 unrelated Chinese Han individuals residing in Northern China (Hebei, Henan, and Shanxi provinces) (Fig. S1). Supplementary material related to this article found, in the online version, at http://dx.doi.org/10.1016/j.fsigen.2015.07.019. Bloodstain samples of 1027 (male 506, female 521) unrelated healthy individuals were collected after obtaining informed consent. DNA was extracted using the Chelex-100 protocol [2]. The quantity of recovered DNA was determined by Qubit Quantitation System (Invitrogen, CA, USA), according to the manufacturers specifications. DNA samples were amplified using two kits: Microreader 21 ID system (Microread Genetics Incorporation, China), which included Amelogenin and 20 autosomal loci (i.e., CSF1PO, D12S391, D13S317, D16S539, D18S51, D19S433, D21S11, D2S1338, D2S441, D3S1358, D5S818, D6S1043, D7S82, D8S1179, FGA, Penta D, Penta E, THO1, TPOX, vWA), and Microreader 23sp ID system, which included Amelogenin and 22 autosomal loci (i.e., D6S477, D18S535, D19S253, D15S659, D11S2368, D20S470, D1S1656, D22GATA198B05, D8S1132, D4S2366, D21S1270, D13S325, D9S925, D3S3045, D14S608, D10S1435, D12S391, D7S3048, D17S1290, D5S2500, D2S1338, D16S539). Both kits contain D12S391, D16S539, and D2S1338, which could be used for sample concordance. Polymerase chain reaction (PCR) was conducted with the GeneAmp PCR System 9700 Thermal Cycler (Applied Biosystems, Foster City, CA, USA). Amplified products were separated by capillary electrophoresis on an ABI PRISM 3130XL Genetic Analyzer (Applied Biosystems, Foster City, CA, USA). Data were analyzed using Genemapper ID 3.2 software (Applied Biosystems, Foster City, CA, USA). Allelic frequencies and forensic parameters were evaluated using Powerstats version 1.2 (Promega, Madison, WI, USA). Hardy– Weinberg Equilibrium (HWE) of each locus and the linkage disequilibrium (LD) for all pair-wise STR loci were tested using the Genepop Version 4.2 software package (http://genepop.curtin.edu. au). To estimate the inter-population differentiation between the

Genetic analysis of 17 Y-chromosomal STR loci of Chinese Tujia ethnic group residing in Youyang Region of Southern China.

Y-STR haplotype data were obtained in a population sample of 197 unrelated healthy male individuals of Chinese Tujia ethnic minority group residing in an autonomous county of Southern China using 17 Y-chromosome STR markers. A total of 197 haplotypes were identified in the set of Y-STR loci. The overall haplotype diversity for the Tujia population at 17 Y-STR loci was 1.0000±0.0005. Genetic distance was estimated between this population and other 14 Chinese populations including Paiwan and Atayal populations of Taiwan, and Southern Han, Dong, Jing, Miao, Yao, Zhuang, Yi, Maonan, She, Hui, Sala, and Tibetan ethnic groups. The results demonstrated that the 17 Y-STR loci analyzed were highly polymorphic in Tujia ethnic group examined and hence useful for forensic cases, paternity testing, and population genetic studies.

Characterization of miRNomes in Acute and Chronic Myeloid Leukemia Cell Lines

Myeloid leukemias are highly diverse diseases and have been shown to be associated with microRNA (miRNA) expression aberrations. The present study involved an in-depth miRNome analysis of two human acute myeloid leukemia (AML) cell lines, HL-60 and THP-1, and one human chronic myeloid leukemia (CML) cell line, K562, via massively parallel signature sequencing. mRNA expression profiles of these cell lines that were established previously in our lab facilitated an integrative analysis of miRNA and mRNA expression patterns. miRNA expression profiling followed by differential expression analysis and target prediction suggested numerous miRNA signatures in AML and CML cell lines. Some miRNAs may act as either tumor suppressors or oncomiRs in AML and CML by targeting key genes in AML and CML pathways. Expression patterns of cell type-specific miRNAs could partially reflect the characteristics of K562, HL-60 and THP-1 cell lines, such as actin filament-based processes, responsiveness to stimulus and phagocytic activity. miRNAs may also regulate myeloid differentiation, since they usually suppress differentiation regulators. Our study provides a resource to further investigate the employment of miRNAs in human leukemia subtyping, leukemogenesis and myeloid development. In addition, the distinctive miRNA signatures may be potential candidates for the clinical diagnosis, prognosis and treatment of myeloid leukemias.