Biology subjects

Hou, L.

Publications and source records attributed to Hou, L..

90 records · Page 5Linked to original sources

bioRxiv2020

A potent neutralizing human antibody reveals the N-terminal domain of the Spike protein of SARS-CoV-2 as a site of vulnerability

The pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents a global public health threat. Most research on therapeutics against SARS-CoV-2 focused on the receptor binding domain (RBD) of the Spike (S) protein, whereas the vulnerable epitopes and functional mechanism of non-RBD regions are poorly understood. Here we isolated and characterized monoclonal antibodies (mAbs) derived from convalescent COVID-19 patients. An mAb targeting the N-terminal domain (NTD) of the SARS-CoV-2 S protein, named 4A8, exhibits high neutralization potency against both authentic and pseudotyped SARS-CoV-2, although it does not block the interaction between angiotensin-converting enzyme 2 (ACE2) receptor and S protein. The cryo-EM structure of the SARS-CoV-2 S protein in complex with 4A8 has been determined to an overall resolution of 3.1 Angstrom and local resolution of 3.4 Angstrom for the 4A8-NTD interface, revealing detailed interactions between the NTD and 4A8. Our functional and structural characterizations discover a new vulnerable epitope of the S protein and identify promising neutralizing mAbs as potential clinical therapy for COVID-19.

biochemistry↗

bioRxiv2020

Dexmedetomidine mediates microRNA-185 to suppress ovarian cancer growth via inhibiting the SOX9/Wnt/β-catenin signaling pathway

ObjectiveCervical cancer (CC) is a serious health problem, causing heavy burden each year worldwide. Long non-coding RNA (lncRNA) is implicated in CC progression. This study aims to clarify the underlying mechanism of lncRNA HAND2-AS1 in CC cellular process. MethodLncRNA expression in CC tissues and adjacent tissues was analyzed via Gene Expression Omnibus microarray. The levels of HAND2-AS1, microRNA (miR)-21 and ALEX1 in 54 cases of CC tissues, adjacent tissues, CC cell lines and normal breast cells were detected. The malignant biological behaviors of CC cells were detected after overexpressing HAND2-AS1 or inhibiting miR-21 expression. Bioinformatics analysis, luciferase reporter assay and RNA-pull down assay were performed to verify the relationship among HAND2-AS1, miR-21 and ALEX1. The effects of HAND2-AS1 on CC cell growth in vivo were verified by nude mice transplantation experiment. ResultsHAND2-AS1 was lowly expressed in CC tissues and cells, and HAND2-AS1 functioned as a competitive endogenous RNA of miR-21 and enhanced ALEX1 expression and downregulated JAK1/STAT3 pathway to inhibit malignant biological behavior of CC cells. Overexpression of HAND2-AS1 or silencing of miR-21 can inhibit the malignant biological behavior of CC cells. Moreover, overexpression of HAND2-AS1 can inhibit the growth of CC cells in vivo. ConclusionOur data supported that lncRNA HAND2-AS1 promoted ALEX1 expression through competitively binding to miR-21, thereby inhibiting the proliferation and epithelial-mesenchymal transformation and promoting apoptosis of CC cells.

cell biology↗

bioRxiv2019

Detecting Local Genetic Correlations with Scan Statistics

Genetic correlation analysis has quickly gained popularity in the past few years and provided insights into the genetic etiology of numerous complex diseases. However, existing approaches oversimplify the shared genetic architecture between different phenotypes and cannot effectively identify precise genetic regions contributing to the genetic correlation. In this work, we introduce LOGODetect, a powerful and efficient statistical method to identify small genome segments harboring local genetic correlation signals. LOGODetect automatically identifies genetic regions showing consistent associations with multiple phenotypes through a scan statistic approach. It uses summary association statistics from genome-wide association studies (GWAS) as input and is robust to sample overlap between studies. Applied to five phenotypically distinct but genetically correlated psychiatric disorders, we identified 49 non-overlapping genome regions associated with multiple disorders, including multiple hub regions showing concordant effects on more than two disorders. Our method addresses critical limitations in existing analytic strategies and may have wide applications in post-GWAS analysis.

genetics↗

bioRxiv2019

Effect of recombinant phycocyanin on photosynthetic system in Chlamydomonas reinhardtii

The phycobilisome is an important photosynthetic antenna in the photosynthetic cyanobacteria, and phycocyanin is one of the main components of phycobilisomes. It helps cells absorb green light that green-lineage photo-synthetic organisms cannot. In this work, phycocyanin, heme oxidase and ferredoxin oxidoreductase from Arthrospira platensis FACHB 314 were successfully expressed in the green algae Chlamydomonas reinhardtii. Then the effects of this expression on the photosynthesis and growth of C. reinhardtii were detected. Transcriptional level analysis showed that the phycocyanin gene was successfully expressed stably in the transgenic strains. The results of low-temperature fluorescence emission spectra and chlorophyll fluorescence showed that recombinant phycocyanin has considerable optical activity. The expression of phycocyanin, heme oxidase and ferredoxin oxidoreductase in low-light conditions is particularly evident in the promotion of photosynthesis in C. reinhardtii. The growth of transgenic strains was significantly promoted in the early growth phase under low-light conditions. However, the final growth and biomass accumulation of transgenic C. reinhardti were inhibited by this expression. In this paper, the possibility of photoenergy transfer between phycocyanin and heterologous host thylakoid membrane was researched, which provided a useful attempt for the construction of a new photosynthetic system using phycobiliprotein from cyanobacteria.\n\nOne-sentence summaryPhycocyanin from Arthrospira platensis FACHB 314 expressed in Chlamydomonas reinhardtii can effect the photosynthetic system of C. reinhardtii.

molecular biology↗

bioRxiv2019

Junction-skipping regulation in complex disease

Multiple mRNA isoforms can be generated from a single gene locus through alternative splicing. Abnormality in alternative splicing has been linked to many human disorders. Here using RNA-seq data from 48 tissues from GTEx v7 release and summary statistics from GWAS of complex diseases and traits, we present a study to identify genomic variants regulating junction-skipping with the goal to understand their contribution to complex diseases and traits. For each tissue, we found 48 - 575 junction-skipping events regulated by genomic variants. We performed fine-mapping on both the junction-skipping association and 23 complex disease and trait associations and mapped them to 95% credible sets. We found 13 - 279 junction-skipping regulations were mapped to a credible set with [≤]5 variants. On the genome-wide scale, we noted a clear disease-tissue specificity. Results from this approach provided critical insights into the functional mechanism of the genetic disease associations and contributed to our understanding of the genetic architecture of human complex disorders.

genetics↗

bioRxiv2019

Methylome-Wide Association Study Of Central Adiposity Implicates Genes Involved In Immune And Endocrine Systems

We conducted a methylome-wide association study to examine associations between DNA methylation in whole blood and central adiposity and body fat distribution, measured as waist circumference, waist- to-hip ratio, and waist-to-height ratio adjusted for body mass index, in 2684 African American adults in the Atherosclerosis Risk in Communities study. We validated significantly associated Cytosine-phosphate-Guanine methylation sites (CpGs) among adults using the Womens Health Initiative and Framingham Heart Study participants (combined N=5743) and generalized associations in adolescents from The Raine Study (N=820). We identified 11 CpGs that were robustly associated with one or more central adiposity trait in adults and 2 in adolescents, including CpG site associations near TXNIP, ADCY7, SREBF1, and RAP1GAP2 that had not previously been associated with obesity-related traits.

genomics↗

bioRxiv2019

Offspring production of ovarian organoids derived from spermatogonial stem cells by chromatin reorganization

Fate determination of germline stem cells remains poorly understood at the chromatin structure level1,2. Here, we demonstrate successful production of offspring from oocytes transdifferentiated from mouse spermatogonial stem cells (SSCs) with tracking of transplanted SSCs in vivo, single cell whole exome sequencing, and in 3D cell culture reconstitution of the process of oogenesis derived from SSCs. Furthermore, we demonstrate direct induction of germline stem cells (iGSCs) differentiated into functional oocytes by transduction of H19, Stella, and Zfp57 and inactivation of Plzf in SSCs after screening with ovarian organoids. Using high throughput chromosome conformation, we uncovered extensive chromatin reorganization during SSC conversion into iGSCs, which was highly similar to female germline stem cells. We observed that although topologically associating domains were stable during SSC conversion, chromatin interactions changed in a striking manner, altering 35% of inactive and active chromosomal compartments throughout the genome. These findings have important implications in various areas including mammalian gametogenesis, genetic and epigenetic reprogramming, biotechnology, and medicine.

genetics↗

bioRxiv2019

KIT ligand protects against both light-induced and genetic photoreceptor degeneration

Photoreceptor cell degeneration is a major cause of blindness and a considerable health burden during aging but effective therapeutic or preventive strategies have not so far become commercially available. Here we show in mouse models that signaling through the tyrosine kinase receptor KIT protects photoreceptor cells against both light-induced and inherited retinal degeneration. Upon light damage, photoreceptor cells upregulate Kit ligand (KITL) and activate KIT signaling, which in turn induces nuclear accumulation of the transcription factor NRF2 and stimulates the expression of the antioxidant gene Hmox1. Conversely, a viable Kit mutation promotes light-induced photoreceptor damage, which is reversed by experimental expression of Hmox1. Furthermore, overexpression of KITL from a viral AAV8 vector prevents photoreceptor cell death and partially restores retinal function after light damage or in genetic models of human retinitis pigmentosa. Hence, application of KITL may provide a novel therapeutic avenue for prevention or treatment of retinal degenerative diseases.

neuroscience↗

bioRxiv2019

Bacterial fucosidase enables the production of Bombay red blood cells

We present a method to produce H antigen-deficient red blood cells (RBCs) for transfusion to individuals with anti-H antibodies. A fucosidase from bacteria was heterologously expressed efficiently in E. coli and has been demonstrated to completely remove H antigens on the surface of human RBCs in a facile conversion process. The approach we describe here holds promise for making H-deficient RBCs available for a rare population beyond ABO types.

molecular biology↗

bioRxiv2019

Diverse noncanonical PAMs recognized by SpCas9 in human cells

The CRISPR/Cas9 system derived from Streptococcus pyogenes (SpCas9) provides unprecedented genome editing capabilities, but the potential for off-target mutations limits its application. In addition to NGG protospacer adjacent motif (PAM), off-target mutations are also associated with noncanonical PAMs, which have not yet been systematically evaluated. Here, we developed a highly sensitive approach that allows systematically analyzing PAM sequences in human cells, and identified multiple alternative PAMs recognized by SpCas9.

bioengineering↗

bioRxiv2019

Mapping of transgenic alleles in plants using a Nanopore-based sequencing strategy

Transgenic technology was developed to introduce transgenes into various organisms to validate gene function and add genetic variation for the development of beneficial input or output trait over 40 years ago. However, the identification of the transgene insertion position in the genome, while doable, can be cumbersome in the organisms with complex genomes. Here, we report a Nanopore-based sequencing method to rapidly map transgenic alleles in the soybean genome. This strategy is high-throughput, convenient, reliable, and cost-efficient. The transgenic allele mapping protocol outlined herein can be easily translated to other higher eukaryotes with complex genomes.

plant biology↗

bioRxiv2018

Novel DNA methylation sites of glucose and insulin homeostasis: an integrative cross-omics analysis

Despite existing reports on differential DNA methylation in type 2 diabetes (T2D) and obesity, our understanding of the functional relevance of the phenomenon remains limited. Because obesity is the main risk factor for T2D and a driver of methylation from previous study, we aimed to explore the effect of DNA methylation in the early phases of T2D pathology while accounting for body mass index (BMI). We performed a blood-based epigenome-wide association study (EWAS) of fasting glucose and insulin among 4,808 non-diabetic European individuals and replicated the findings in an independent sample consisting of 11,750 non-diabetic subjects. We integrated blood-based in silico cross-omics databases comprising genomics, epigenomics and transcriptomics collected by BIOS project of the Biobanking and BioMolecular resources Research Infrastructure of the Netherlands (BBMRI-NL), the Meta-Analyses of Glucose and Insulin-related traits Consortium (MAGIC), the DIAbetes Genetics Replication And Meta-analysis (DIAGRAM) consortium, and the tissue-specific Genotype-Tissue Expression (GTEx) project. We identified and replicated nine novel differentially methylated sites in whole blood (P-value < 1.27 x 10-7): sites in LETM1, RBM20, IRS2, MAN2A2 genes and 1q25.3 region were associated with fasting insulin; sites in FCRL6, SLAMF1, APOBEC3H genes and 15q26.1 region were associated with fasting glucose. The association between SLAMF1, APOBEC3H and 15q26.1 methylation sites and glucose emerged only when accounted for BMI. Follow-up in silico cross-omics analyses indicate that the cis-acting meQTLs near SLAMF1 and SLAMF1 expression are involved in glucose level regulation. Moreover, our data suggest that differential methylation in FCRL6 may affect glucose level and the risk of T2D by regulating FCLR6 expression in the liver. In conclusion, the present study provided nine new DNA methylation sites associated with glycemia homeostasis and also provided new insights of glycemia related loci into the genetics, epigenetics and transcriptomics pathways based on the integration of cross-omics data in silico.

genomics↗

bioRxiv2018

Novel 5-Hydroxymethylcytosine Markers for Pancreatic Cancer

OBJECTIVESRobust biomarkers for pancreatic cancer (PaC) early detection/prognosis are critical for improved patient survival. Our goal was to explore the biomarker potential of 5-hydroxymethylcytosines (5hmC), an epigenetic marker with a distinct role in cancer pathobiology, yet under-investigated due largely to technical constraints.\n\nMETHODSWe used the TAB-Array assay, a state-of-the-art technology to directly profile 5hmC at single base resolution with the Illumina EPIC array (>850,000 CpG sites) in 17 pairs of tumor/adjacent tissue samples from US patients.\n\nRESULTSWe demonstrated distinctive distributions of 5hmC in tissues, and substantial differences between tumor and adjacent tissues, suggesting their diagnostic/prognostic value of for PaC.\n\nCONCLUSIONThis study established the potential of 5hmC as a novel epigenetic biomarker for PaC.

cancer biology↗

bioRxiv2018

COMPASS Family Histone Methyltransferase ASH2L Mediates Corticogenesis via Transcriptional Regulation of Wnt Signalling

Cell fate specification in neural progenitor cells (NPCs) is orchestrated via extrinsic and intrinsic molecular programs, and histone methylation in these decisions has been ascribed to a crucial function regulating gene expression. Here, we show that the COMPASS family histone methyltransferase co-factor ASH2L is required in NPCs proliferation and upper layer cortical projection neurons production and position. Deletion of Ash2l impairs trimethylation of H3K4 and transcriptional machinery specifically for subsets of Wnt-{beta}-catenin signalling, disrupting their transcription and consequently inhibiting the proliferation ability of NPCs in late stages of neurogenesis. Consistently, Ash2l conditional mutants exhibit thinning neocortex with reduced upper layer neurons and altered neuronal position. Moreover, overexpressing {beta}-catenin after Ash2l elimination or knockdown can rescue the proliferation deficiency of NPCs both in vivo and in vitro. These results demonstrate an essential and highly specific role for Ash2l in controlling NPCs proliferation and late-born neurons lamination in corticogenesis via transcriptionally regulating Wnt-{beta}-catenin signalling, and provide clues to how the COMPASS family epigenetic factors coordinate cell fate determination during cortex development.

neuroscience↗

bioRxiv2018

An epigenetic biomarker of aging for lifespan and healthspan

Identifying reliable biomarkers of aging is a major goal in geroscience. While the first generation of epigenetic biomarkers of aging were developed using chronological age as a surrogate for biological age, we hypothesized that incorporation of composite clinical measures of phenotypic age that capture differences in lifespan and healthspan may identify novel CpGs and facilitate the development of a more powerful epigenetic biomarker of aging. Using a innovative two-step process, we develop a new epigenetic biomarker of aging, DNAm PhenoAge, that strongly outperforms previous measures in regards to predictions for a variety of aging outcomes, including all-cause mortality, cancers, healthspan, physical functioning, and Alzheimers disease. While this biomarker was developed using data from whole blood, it correlates strongly with age in every tissue and cell tested. Based on an in-depth transcriptional analysis in sorted cells, we find that increased epigenetic, relative to chronological age, is associated increased activation of pro-inflammatory and interferon pathways, and decreased activation of transcriptional/translational machinery, DNA damage response, and mitochondrial signatures. Overall, this single epigenetic biomarker of aging is able to capture risks for an array of diverse outcomes across multiple tissues and cells, and provide insight into important pathways in aging.

epidemiology↗

bioRxiv2017

Genetic pleiotropy between mood disorders, metabolic, and endocrine traits in a multigenerational pedigree

Bipolar disorder (BD) is a mental disorder characterized by alternating periods of depression and mania. Individuals with BD have higher levels of early mortality than the general population, and a substantial proportion of this may be due to increased risk for comorbid diseases. Recent evidence suggests that pleiotropy, either in the form of a single risk-allele or the combination of multiple loci genome-wide, may underlie medical comorbidity between traits and diseases. To identify the molecular events that underlie BD and related medical comorbidities, we generated imputed whole genome sequence (WGS) data using a population specific reference panel, for an extended multigenerational Old Order Amish pedigree (400 family members) segregating BD and related disorders. First, we investigated all putative disease-causing variants at known Mendelian disease loci present in this pedigree. Second, we performed genomic profiling using polygenic risk scores to establish each individual's risk for several complex diseases. To explore the contribution of disease genes to BD we performed gene-based and variant-based association tests for BD, and found that Mendelian disease genes are enriched in the top results from both tests (OR=20.3, p=1x10-3; OR=2.2, p=1x10-2). We next identified a set of Mendelian variants that co-occur in individuals with BD more frequently than their unaffected family members, including the R3527Q mutation in APOB associated with hypercholesterolemia. Using polygenic risk scores, we demonstrated that BD individuals from this pedigree were enriched for the same common risk-alleles for BD as in the general population ({beta}=0.416, p=6x10-4). Furthermore, in the extended Amish family we find evidence for a common genetic etiology between BD and clinical autoimmune thyroid disease (p=1x10-4), diabetes (p=1x10-3), and lipid traits such as triglyceride levels (p=3x10-4). We identify genomic regions that contribute to the differences between BD individuals and unaffected family members by calculating local genetic risk for independent LD blocks. Our findings provide evidence for the extensive genetic pleiotropy that can drive epidemiological findings of comorbidities between diseases and other complex traits. Identifying such patterns may enable the subtyping of complex diseases and facilitate our understanding of the genetic mechanisms underlying phenotypic heterogeneity.

genetics↗

bioRxiv2017

Sodium valproate rescues expression of TRANK1 in iPSC-derived neural cells that carry a genetic variant associated with serious mental illness

Biological characterization of genetic variants identified in genome-wide association studies (GWAS) remains a substantial challenge. Here we used human induced pluripotent stem cells (hiPSC) and their neural derivatives to characterize common variants on chromosome 3p22 that have been associated by GWAS with major mental illnesses. HiPSC-derived neural progenitor cells carrying the risk allele of the single nucleotide polymorphism (SNP), rs9834970, displayed lower baseline TRANK1 expression that was rescued by chronic treatment with therapeutic dosages of valproic acid (VPA). Although rs9834970 has no known function, we demonstrated that a nearby SNP, rs90832, strongly affects binding by the transcription factor, CTCF, and that the high-affinity allele usually occurs on haplotypes carrying the rs9834970 risk allele. Decreased expression of TRANK1 perturbed expression of many genes involved in neural development and differentiation. These findings have important implications for the pathophysiology of major mental illnesses and the development of novel therapeutics.\n\nHighlightsO_LIhiPSC-derived neural cells carrying a mental illness risk allele showed lower expression of TRANK1\nC_LIO_LIValproic acid rescued TRANK1expression in cells carrying the risk allele\nC_LIO_LIRisk haplotypes usually carry an allele that increased CTCF binding\nC_LIO_LIReduced expression of TRANK1 perturbed genes involved in neural development and differentiation\nC_LI\n\nIn BriefUsing neural derivatives of human induced pluripotent stem cells, Jiang et al. demonstrate that genetic variants associated with mental illness alter transcription factor binding and decrease expression of a nearby gene, an effect which is rescued by valproic acid.

genetics↗

bioRxiv2017

GWAS of epigenetic ageing rates in blood reveals a critical role for TERT

DNA methylation age is an accurate biomarker of chronological age and predicts lifespan, but its underlying molecular mechanisms are unknown. In this genome-wide association study of 9,907 individuals, we found gene variants mapping to five loci associated with intrinsic epigenetic age acceleration (IEAA) and gene variants in 3 loci associated extrinsic epigenetic age acceleration (EEAA). Mendelian randomization analysis suggested causal influences of menarche and menopause on IEAA and lipid levels on IEAA and EEAA. Variants associated with longer leukocyte telomere length (LTL) in the telomerase reverse transcriptase gene (TERT) locus at 5p15.33 confer higher IEAA (P<2.7x10-11). Causal modelling indicates TERT-specific and independent effects on LTL and IEAA. Experimental hTERT expression in primary human fibroblasts engenders a linear increase in DNA methylation age with cell population doubling number. Together, these findings indicate a critical role for hTERT in regulating the DNA methylation clock, in addition to its established role of compensating for cell replication-dependent telomere shortening.

genetics↗