Biology subjects

Li, S.

Publications and source records attributed to Li, S..

At least 1,009 records · Page 56Linked to original sources

bioRxiv2021

An artificial cell containing cyanobacteria for endosymbiosis mimicking

The bottom-up constructed artificial cells help to understand the cell working mechanism and provide the evolution clues for organisms. Cyanobacteria are believed to be the ancestors of chloroplasts according to endosymbiosis theory. Herein we demonstrate an artificial cell containing cyanobacteria to mimic endosymbiosis phenomenon. The cyanobacteria sustainably produce glucose molecules by converting light energy into chemical energy. Two downstream "metabolic" pathways starting from glucose molecules are investigated. One involves enzyme cascade reaction to produce H2O2 (assisted by glucose oxidase) first, followed by converting Amplex red to resorufin (assisted by horseradish peroxidase). The more biological one involves nicotinamide adenine dinucleotide (NADH) production in the presence of NAD+ and glucose dehydrogenase. Further, NADH molecules are oxidized into NAD+ by pyruvate catalyzed by lactate dehydrogenase, meanwhile, lactate is obtained. Therefore, the sustainable cascade cycling of NADH/NAD+ is built. The artificial cells built here simulate the endosymbiosis phenomenon, meanwhile pave the way for investigating more complicated sustainable energy supplied metabolism inside artificial cells.

synthetic biology↗

bioRxiv2021

Ultrapotent bispecific antibodies neutralize emerging SARS-CoV-2 variants

The emergence of SARS-CoV-2 variants that threaten the efficacy of existing vaccines and therapeutic antibodies underscores the urgent need for new antibody-based tools that potently neutralize variants by targeting multiple sites of the spike protein. We isolated 216 monoclonal antibodies targeting SARS-CoV-2 from plasmablasts and memory B cells of COVID-19 patients. The three most potent antibodies targeted distinct regions of the RBD, and all three neutralized the SARS-CoV-2 variants B.1.1.7 and B.1.351. The crystal structure of the most potent antibody, CV503, revealed that it binds to the ridge region of SARS-CoV-2 RBD, competes with the ACE2 receptor, and has limited contact with key variant residues K417, E484 and N501. We designed bispecific antibodies by combining non-overlapping specificities and identified five ultrapotent bispecific antibodies that inhibit authentic SARS-CoV-2 infection at concentrations of <1 ng/mL. Through a novel mode of action three bispecific antibodies cross-linked adjacent spike proteins using dual NTD/RBD specificities. One bispecific antibody was >100-fold more potent than a cocktail of its parent monoclonals in vitro and prevented clinical disease in a hamster model at a 2.5 mg/kg dose. Notably, six of nine bispecific antibodies neutralized B.1.1.7, B.1.351 and the wild-type virus with comparable potency, despite partial or complete loss of activity of at least one parent monoclonal antibody against B.1.351. Furthermore, a bispecific antibody that neutralized B.1.351 protected against SARS-CoV-2 expressing the crucial E484K mutation in the hamster model. Thus, bispecific antibodies represent a promising next-generation countermeasure against SARS-CoV-2 variants of concern.

immunology↗

bioRxiv2021

The effect of histone deacetylase inhibitor Trichostatin A on IL-17A-induced transformation of MRC5 into myofibroblasts and its mechanism

ObjectiveTo elucidate potential IL-17A- and TSA-mediated regulation of fibroblasts transformation. MethodsMTT assay, HDAC1 activity assay, cell immunofluorescence and Western blot were employed to detect the expression of related indicators. ResultsMRC5 cells expressed only a small amount of Vimentin. IL-17A treatment upregulated MRC5 cell proliferation, in a concentration-dependent manner. TSA treatment, however, suppressed MRC5 cell proliferation. IL-17A treatment also upregulated HDAC1 activity in MRC5 cells, in a concentration-dependent manner. Using immunofluorescence, we demonstrated that IL-17A-treated MRC5 cells had markedly elevated Vimentin, Collagen-I and a-SMA levels, compared to controls. However, a combined treatment of IL-17A and TSA resulted in markedly reduced levels of the Vimentin, Collagen-I and a-SMA, compared to IL-17A alone, yet the amount was higher than controls. Using western blot analysis, we also revealed that the IL-17A-treated MRC5 cells had markedly elevated levels of Vimentin, a-SMA, HDAC1, p-Smad2, and p-Smad3, and markedly reduced level of Smad7, compared to controls. In TSA intervention group, the expression effect of the above protein was opposite. Moreover, no discernible difference was observed in the levels of Smad2 and Smad3 among the treated and un-treated groups. ConclusionIL-17A stimulates proliferation of MRC5 cells and increases HDAC1 activity and protein expression. It also transforms MRC5 cells into myofibroblasts via activation of the TGF -{beta}1/ Smads signaling network. TSA, on the other hand, strongly suppresses TGF -{beta}1/ Smads pathway-mediated fibrosis by ceasing HDAC1 activity and protein expression.

cell biology↗

bioRxiv2021

CNAHap: a germline haplotyping method using tumor allele-specific copy number alteration

Haplotype phasing is indispensable to study human genetics. The pervasiveness of large copy number variant segments in solid tumors brings possibilities to resolve long germline phasing blocks utilizing allele imbalance in tumor data. Although there exist such studies, none of them provide easy-use software based on availability and usability. Herein, we present a novel tool, CNAHap, to determine the allele-specific copy number in tumor and then phase germline variants according to the imbalanced alleles in tumor genomes. We also provide interactive web interfaces to visualize the copy number and phase landscape from CNAHap. On in silico datasets, CNAHap demonstrates higher allele-specific copy number calling accuracy than the benchmark tool and generates long phasing blocks. As a case study on Hepatocellular carcinoma, CNAHap successfully generates huge phase blocks with the averages of N50 and N90 as 25M and 7M, respectively, and finds the Olfactory receptor family is recurrent amplified. Our results illustrate the efficacy of CNAHap in determining tumor allele-specific copy numbers and their long germline haplotypes. CNAHap is available at https://github.com/bowentan/CNAHap and the CNAHap visualization web interfaces are hosted at bio.oviz.org.

bioinformatics↗

bioRxiv2021

Occurrence of COVID-19 symptoms during SARS-CoV-2 infection defines waning of humoral immunity

Approximately half of the SARS-CoV-2 infections occur without apparent symptoms, raising questions regarding long-term humoral immunity in asymptomatic individuals. Plasma levels of immunoglobulin G (IgG) and M (IgM) against the viral spike or nucleoprotein were determined for 25,091 individuals enrolled in a surveillance program in Wuhan, China. We compared 405 asymptomatic individuals with 459 symptomatic COVID-19 patients. The well-defined duration of the SARS-CoV-2 endemic in Wuhan allowed a side-by-side comparison of antibody responses following symptomatic and asymptomatic infections without subsequent antigen re-exposure. IgM responses rapidly declined in both groups. However, both the prevalence and durability of IgG responses and neutralizing capacities correlated positively with symptoms. Regardless of sex, age, and body weight, asymptomatic individuals lost their SARS-CoV-2-specific IgG antibodies more often and rapidly than symptomatic patients. These findings have important implications for immunity and favour immunization programs including individuals after asymptomatic infections. One-Sentence SummaryPrevalence and durability of SARS-CoV-2-specific IgG responses and neutralizing capacities correlate with COVID-19 symptoms.

immunology↗

bioRxiv2021

An empirical pipeline for personalized diagnosis of Lafora disease mutations

Lafora disease (LD) is a fatal, insidious metabolic disorder characterized by progressive myoclonic epilepsy manifesting in the teenage years, rapid neurological decline, and death typically within ten years of onset. Mutations in either EPM2A, encoding the glycogen phosphatase laforin, or EPM2B, encoding the E3 ligase malin, cause LD. Whole exome sequencing has revealed many EPM2A variants associated with late-onset or slower disease progression. We established an empirical pipeline for characterizing laforin missense mutations in vitro using complimentary biochemical approaches. Analysis of 26 mutations revealed distinct functional classes associated with different outcomes supported by multiple clinical cases. For example, F321C and G279C mutations have attenuated functional defects and are associated with slow progression. This pipeline allows rapid characterization and classification of novel EPM2A mutations, enabling clinicians and researchers to rapidly utilize genetic information to guide treatment of LD patients.

biochemistry↗

bioRxiv2021

Autism_genepheno: Text mining of gene-phenotypeassociations reveals new phenotypic profiles ofautism-associated genes

Autism is a spectrum disorder with wide variation in type and severity of symptoms. Understanding gene-phenotype associations is vital to unravel the disease mechanisms and advance its diagnosis and treatment. To date, several databases have stored a large portion of gene-phenotype associations which are mainly obtained from genetic experiments. However, a large proportion of gene-phenotype associations are still buried in the autism-related literature and there are limited resources to investigate autism-associated gene-phenotype associations. Given the abundance of the autism-related literature, we were thus motivated to develop Autism_genepheno, a text mining pipeline to identify sentence-level mentions of autism-associated genes and phenotypes in literature through natural language processing methods. We have generated a comprehensive database of gene-phenotype associations in the last five years autism-related literature that can be easily updated as new literature becomes available. We have evaluated our pipeline through several different approaches, and we are able to rank and select top autism-associated genes through their unique and wide spectrum of phenotypic profiles, which could provide a unique resource for the diagnosis and treatment of autism. The data resources and the Autism_genpheno pipeline are available at: https://github.com/maiziezhoulab/Autism_genepheno.

bioinformatics↗

bioRxiv2021

A novel method for generating 3D constructs with branched vascular networks using multi-materials bioprinting and direct surgical anastomosis

Vessels pervade almost all body tissues, and significantly influence the pathophysiology of human body. Previous attempts to establish multi-scale vascular connection and function in 3D model tissues using bioprinting have had limited success due to the incoordination between cell-laden materials and stability of the perfusion channel. Here, we report a methodology to fabricate centimetre-scale vascularized soft tissue with high viability and accuracy using multi-materials bioprinting involving inks with low viscosity and a customized multistage-temperature-control printer. The tissue formed was perfused with branched vasculature with well-formed 3D capillary network and lumen, which would potentially supply the cellular components with sufficient nutrients in the matrix. Furthermore, the same methodology was applied for generating liver-like tissue with the objective to fabricate and mimic a mature and functional liver tissue, with increased functionality in terms of synthesis of liver specific proteins after in vitro perfusion and in vivo subperitoneal transplantation in mice. Moreover, to establish immediate blood perfusion, an elastic layer was printed wrapping sacrificial ink to support the direct surgical anastomosis of the carotid artery to the jugular vein. Our findings highlight the support extended by vasculature network in soft hydrogels which helps to sustain the thick and dense cellularization in engineered tissues.

bioengineering↗

bioRxiv2021

Combined Inhibition of SHP2 and CXCR1/2 Promotes Anti-Tumor T Cell Response in NSCLC

Clinical trials of SHP2 inhibitors (SHP2i) alone and in various combinations are ongoing for multiple tumors with over-activation of the RAS/ERK pathway. SHP2 plays critical roles in normal cell signaling; hence, SHP2is could influence the tumor microenvironment. We found that SHP2i treatment depleted alveolar and M2-like macrophages and promoted B and T lymphocyte infiltration in Kras- and Egfr-mutant non-small cell lung cancer (NSCLC). However, treatment also increased intratumor gMDSCs via tumor-intrinsic, NF-kB-dependent production of CXCR2 ligands. Other RAS/ERK pathway inhibitors also induced CXCR2 ligands and gMDSC influx in mice, and CXCR2 ligands were induced in tumors from patients on KRASG12C-inhibitor trials. Combined SHP2(SHP099)/CXCR1/2(SX682) inhibition depleted a specific cluster of S100a8/9high gMDSCs, generated Klrg1+ CD8+ effector T cells with a strong cytotoxic phenotype but expressing the checkpoint receptor NKG2A, and enhanced survival in Kras-and Egfr-mutant models. Our results argue for testing RAS/ERK pathway/CXCR1/2/NKG2A inhibitor combinations in NSCLC patients. Statement of SignificanceOur study shows that inhibiting the SHP2/RAS/ERK pathway triggers NF-kB-dependent up-regulation of CXCR2 ligands and recruitment of S100A8high gMDSCs, which suppress T cells in NSCLC. Combining SHP2 and CXCR2 inhibitors blocks this gMDSC immigration, resulting in enhanced Th1 polarization, induction of CD8+ KLRG1+ effector T cells with high cytotoxic activity and improved survival in multiple NSCLC models.

cancer biology↗

bioRxiv2021

Nonsense Mediated RNA Decay Is a Unique Vulnerability of Cancer Cells with SF3B1 and U2AF1 Mutations

Nonsense-mediated RNA decay (NMD) is well recognized as an RNA surveillance pathway that targets aberrant mRNAs with premature translation termination codons (PTCs) for degradation; however, its molecular mechanisms and roles in health and disease remain incompletely understood. In this study, we developed a novel reporter system that can accurately measure NMD activity in individual cells. By carrying out a genome-wide CRISPR/Cas9 knockout screen using this reporter system, we identified novel NMD-promoting factors, including multiple components of the SF3B complex and other U2 spliceosome factors. Interestingly, we also found that cells with mutations in the U2 spliceosome genes SF3B1 and U2AF1--which are commonly found in myelodysplastic syndrome (MDS) and cancers--have overall attenuated NMD activity. Furthermore, we found that compared to wild type cells, SF3B1 and U2AF1 mutant cells are more sensitive to NMD inhibition, a phenotype that is accompanied by elevated DNA replication obstruction, DNA damage and chromosomal instability. Remarkably, the sensitivity of spliceosome mutant cells to NMD inhibition could be rescued by overexpression of RNase H1, which removes R-loops in the genome. Together, our findings shed new light on the functional interplay between NMD and RNA splicing and suggest a novel strategy for the treatment of MDS and cancers with spliceosome mutations.

cell biology↗

bioRxiv2021

CD36 family members are TCR-independent ligands for CD1 antigen-presentingmolecules

CD1c presents lipid-based antigens to CD1c-restricted T cells which are thought to be a major component of the human T cell pool. The study of CD1c-restricted T cells, however, is hampered by the presence of an abundantly expressed CD1c-binding partner on blood cells distinct to the T cell receptor (TCR), confounding analysis of TCR-mediated CD1c tetramer staining. Here, we identify the CD36 family (CD36, CD36-L1 and CD36-L2) as novel ligands for CD1c, CD1b and CD1d proteins, and show that CD36 is the receptor responsible for non-TCR-mediated CD1c tetramer staining of blood cells. Moreover, CD36-blockade enables tetramer-based identification of CD1c-restricted T cells and clarifies identification of CD1b- and CD1d-restricted T cells. We use this technique to characterise CD1c-restricted T cells ex vivo and show diverse phenotypic features, TCR repertoire and antigen-specific subsets. Accordingly, this work will enable further studies into the biology of CD1 and human CD1-restricted T cells. One Sentence SummaryCD1 molecules bind CD36 family members and blockade of this interaction facilitates the study of CD1-restricted T cells.

immunology↗

bioRxiv2021

A tandem-repeat dimeric RBD protein-based COVID-19 vaccine ZF2001 protects mice and nonhuman primates

A safe, efficacious and deployable vaccine is urgently needed to control COVID-19 pandemic. We report here the preclinical development of a COVID-19 vaccine candidate, ZF2001, which contains tandem-repeat dimeric receptor-binding domain (RBD) protein with alum-based adjuvant. We assessed vaccine immunogenicity and efficacy in both mice and non-human primates (NHPs). ZF2001 induced high levels of RBD-binding and SARS-CoV-2 neutralizing antibody in both mice and NHPs, and also elicited balanced TH1/TH2 cellular responses in NHPs. Two doses of ZF2001 protected Ad-hACE2-transduced mice against SARS-CoV-2 infection, as detected by reduced viral RNA and relieved lung injuries. In NHPs, vaccination of either 25 g or 50 g ZF2001 prevented infection with SARS-CoV-2 in lung, trachea and bronchi, with milder lung lesions. No evidence of disease enhancement is observed in both models. ZF2001 is being evaluated in the ongoing international multi-center Phase 3 trials (NCT04646590) and has been approved for emergency use in Uzbekistan.

immunology↗

bioRxiv2021

Site-specific steric control of SARS-CoV-2 spike glycosylation

A central tenet in the design of vaccines is the display of native-like antigens in the elicitation of protective immunity. The abundance of N-linked glycans across the SARS-CoV-2 spike protein is a potential source of heterogeneity between the many different vaccine candidates under investigation. Here, we investigate the glycosylation of recombinant SARS-CoV-2 spike proteins from five different laboratories and compare them against infectious virus S protein. We find patterns which are conserved across all samples and this can be associated with site-specific stalling of glycan maturation which act as a highly sensitive reporter of protein structure. Molecular dynamics (MD) simulations of a fully glycosylated spike support s a model of steric restrictions that shape enzymatic processing of the glycans. These results suggest that recombinant spike-based SARS-CoV-2 immunogen glycosylation reproducibly recapitulates signatures of viral glycosylation.

biochemistry↗

bioRxiv2021

Within-sibship GWAS improve estimates of direct genetic effects

Estimates from genome-wide association studies (GWAS) represent a combination of the effect of inherited genetic variation (direct effects), demography (population stratification, assortative mating) and genetic nurture from relatives (indirect genetic effects). GWAS using family-based designs can control for demography and indirect genetic effects, but large-scale family datasets have been lacking. We combined data on 159,701 siblings from 17 cohorts to generate population (between-family) and within-sibship (within-family) estimates of genome-wide genetic associations for 25 phenotypes. We demonstrate that existing GWAS associations for height, educational attainment, smoking, depressive symptoms, age at first birth and cognitive ability overestimate direct effects. We show that estimates of SNP-heritability, genetic correlations and Mendelian randomization involving these phenotypes substantially differ when calculated using within-sibship estimates. For example, genetic correlations between educational attainment and height largely disappear. In contrast, analyses of most clinical phenotypes (e.g. LDL-cholesterol) were generally consistent between population and within-sibship models. We also report compelling evidence of polygenic adaptation on taller human height using within-sibship data. Large-scale family datasets provide new opportunities to quantify direct effects of genetic variation on human traits and diseases.

genetics↗

bioRxiv2021

Dysbiotic oral and gut viromes in untreated and treated rheumatoid arthritis patients

BackgroundRheumatoid arthritis (RA) has been considered to be influenced by bacteria from the oral cavity and gut for many years. Despite potential impact of viruses in RA was mentioned in some studies, specific roles of oral and gut viromes in RA is still unclear. ResultsIn this study, we observed the viral community variation in the oral and gut samples, performed a comparative analysis of oral and gut viromes in health controls, untreated and treated RA patients, and constructed interaction networks among viruses, bacteria, and RA-associated clinical indexes to address the potential associations between viral community and RA. The results showed that the viromes could be isolated from dental plaque, saliva, and feces samples, among which the saliva having the highest with in-sample diversity. Meanwhile, remarkable variations of viral diversity and composition in the oral (i.e., dental plaque and saliva) virome could be observed in RA patients and healthy controls yet in untreated and treated RA patients, with a relatively low variability in the gut virome. Distraction of viruses-bacteria interaction network was discovered in three sites of RA patients. In addition, some RA-associated oral taxa, including Lactococcus phage vOTU70, Bacteroides vulgatus, Lactococcus lactis, Escherichia coli, Neisseria elongate, were correlated to the RA-related clinical indexes. ConclusionWhole-virome analysis illustrated the potential role of oral and gut viral communities in the development of RA.

microbiology↗

bioRxiv2021

Modulation of fatty acid elongation generates sexually dimorphic hydrocarbons and female attractiveness in Blattella germanica (L.)

Insect cuticular hydrocarbons (CHCs) serve as important intersexual signaling chemicals and generally show variation between the sexes, but little is known about the generation of sexually dimorphic hydrocarbons (SDHCs) in insects. Here, we report the molecular mechanism and biological significance that underling the generation of SDHC in the German cockroach, Blattella germanica. Sexually mature females possess more C29 cuticular hydrocarbons (CHCs), especially the contact sex pheromone precursor 3,11-DimeC29. RNAi screen against fatty acid elongase gene family members and combined with heterologous expression revealed that both BgElo12 and BgElo24 were involved in HC production, but BgElo24 is of wide catalytic activities and is able to provides substrates for BgElo12, and only the female-enriched BgElo12 was responsible for sustaining female-specific HC profile. Repressing BgElo12 masculinized the female CHC profile, decreased contact sex pheromone level and consequently reduced the sexual attractiveness of female cockroaches. Moreover, the asymmetric expression of BgElo12 between the sexes is modulated by sex differentiation cascade. Specifically, male-specific BgDsx represses the transcription of BgElo12 in males, while BgTra is able to remove this effect in females. Our study reveals a novel molecular mechanism responsible for the formation of SDHCs, and also provide evidences on shaping of the SDHCs by sexual selection, as females use them to generate high levels of contact sex pheromone.

molecular biology↗

bioRxiv2021

Self-organization of Tissue Growth by Interfacial Mechanical Interactions in Multi-layered Systems

Morphogenesis is a spatially and temporally regulated process involved in various physiological and pathological transformations. In addition to the associated biochemical factors, the physical regulation of morphogenesis has attracted increasing attention. However, the driving force of morphogenesis initiation remains elusive. Here, we show that during the growth of multi-layered tissues, morphogenetic process can be self-organized by the progression of compression gradient stemmed from the interfacial mechanical interactions between layers. In tissues with low fluidity, the compression gradient is progressively strengthened during growth and induces stratification by triggering symmetric-to-asymmetric cell division reorientation at the critical tissue size. In tissues with high fluidity, compression gradient is dynamic and induces cell junction remodelling regulated cell rearrangement leading to 2D in-plane morphogenesis instead of 3D deformation. Morphogenesis can be tuned by manipulating tissue fluidity, cell adhesion forces and mechanical properties to influence the progression of compression gradient during the development of cultured cell sheets and chicken embryos. Together, the dynamics of compression gradient arised from interfacial mechanical interaction provides a conserved mechanism underlying morphogenesis initiation and size control during tissue growth.

biophysics↗

bioRxiv2021

BTBD9 is a novel component of IGF signaling and regulates manganese-induced dopaminergic dysfunction

Restless legs syndrome (RLS) is a common neurological disorder associated with iron deficiency and dopaminergic (DAergic) neuronal dysfunction. BTBD9 is a genetic risk factor for RLS. However, its molecular function remains largely unknown. Here, we report the interaction between BTBD9, manganese (Mn) and insulin/insulin-like growth factor (IGF) signaling in Caenorhabditis elegans, mouse Neuro2a cells and humans. We found that elevated Mn downregulated BTBD9 mRNA levels; in turn, BTBD9 expression attenuated Mn-induced cellular stress and dopaminergic neurodegeneration. As Mn is a known co-factor for insulin receptor and IGF-1 receptor, which activates IGF signaling, we posited that BTBD9 negatively regulates IGF signaling. Our results showed that the protective effects of BTBD9 against Mn toxicity were dependent on the forkhead box O (FOXO) protein. Furthermore, BTBD9 overexpression significantly elevated FOXO level and decreased PKB level, while phosphoinositide-dependent kinase-1 (PDK1) level remained unchanged. We conclude that BTBD9 acts as a key component in the IGF signaling pathway. Meanwhile, the roles of Mn in DAergic neurotoxicity and regulating BTBD9 shed new light on the etiology of RLS.

neuroscience↗