Biology subjects

Feng, C.

Publications and source records attributed to Feng, C..

At least 91 records · Page 5Linked to original sources

bioRxiv2021

A magnetic field prevents alcoholic liver disease by reducing oxidative stress

The radical-pair recombination change will affect the generation of free radicals, which can be regulated by static magnetic fields (SMFs) in a SMF setting dependent way. It is well known that alcohol consumption leads to significantly increased free radical levels and health risks, which lacks effective treatment method besides alcohol abstinence. Here we compared different SMF settings and found that a downward SMF of [~]0.1 T with magnetic flux of [~]4.5x10-3 Wb could effectively alleviate alcohol-induced liver damage and lipid accumulation, and improve liver function. The inflammation, reactive oxygen species (ROS) level and oxidative stress were significantly reduced. EPR (electron paramagnetic resonance) experiments also confirmed the reduced amount of free radical by SMF treatment. Moreover, the lifespan of heavy alcohol drinking mice was also significantly changed due to the SMF effects on liver cell ROS level, DNA synthesis and liver cell regeneration. Our study shows that moderate SMFs with specific parameters have great promises to be developed into a physical method to reduce alcohol-induced liver damage in the future.

physiology↗

bioRxiv2021

Structure-driven effects on genomic DNA damage propensity at G-quadruplex sites

Our genome contains about half a million sites capable of forming G-quadruplex (G4) structures. Such structural formations, often localised at important regulatory loci, have high capability of altering the predisposition of corresponding genomic spans to endogenous and exogenous DNA damage. In this work, we devised an approach to systematically enrich and zoom onto structure-driven effects on the propensity to undergo 9 types of DNA damage: ultraviolet radiation-induced pyrimidine-pyrimidone (6-4) photoproduct PP and cyclobutane pyrimidine dimer CPD couplings (two dyad-based subtypes in each), cisplatin-mediated G-G crosslinks, reactive oxygen species induced 8-oxoguanine damage, DNA fragmentation upon natural decay and fossilisation, breakages from artificial enzymatic cleavage and ultrasound sonication. Our results indicate that the structural effects on DNA damageability at G4 sites are not a simple combination of shielding (G4 strand) and de-shielding (opposite strand) against damaging factors, and the outcomes have different patterns and variation from one damage type to another, highly dependent on the G4 strength and relative strand localisation. The results are accompanied by electronic structure calculations, detailed structural parallels and considerations. Graphical Abstract. An illustration of the considered damage factors acting on G-quadruplex sites, through strand-specific (two pointing thunder signs) and strand-invariant (a single pointing thunder sign) manner. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=151 SRC="FIGDIR/small/471014v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@91e464org.highwire.dtl.DTLVardef@296bc8org.highwire.dtl.DTLVardef@1635413org.highwire.dtl.DTLVardef@24b86a_HPS_FORMAT_FIGEXP M_FIG C_FIG

genomics↗

bioRxiv2021

RNA-dependent RNA polymerases in the black-legged tick produce Argonaute-dependent small RNAs and regulate genes

Small regulatory RNAs (sRNAs) are involved in antiviral defense and gene regulation. Although roles of RNA-dependent RNA Polymerases (RdRPs) in sRNA biology are extensively studied in nematodes, plants and fungi, understanding of RdRP homologs in other animals is still lacking. Here, we study sRNAs in the ISE6 cell line, which is derived from the black-legged tick, an important vector of human and animal pathogens. We find abundant classes of [~]22nt sRNAs that require specific combinations of RdRPs and sRNA effector proteins (Argonautes or AGOs). RdRP-dependent sRNAs possess 5- monophosphates and are mainly derived from RNA polymerase III-transcribed genes and repetitive elements. Knockdown of RdRPs misregulates genes including RNAi-related genes and the regulator of immune response Dsor1. Sensor assays demonstrate that Dsor1 is downregulated by RdRP through the 3UTR that contains a target site of RdRP-dependent repeat-derived sRNAs. Consistent with viral gene repression by the RNAi mechanism using virus-derived small interfering RNAs, viral transcripts are upregulated by AGO knockdown. On the other hand, RdRP knockdown unexpectedly results in downregulation of viral transcripts. This effect is dependent on Dsor1, suggesting that antiviral immunity is enhanced by RdRP knockdown through Dsor1 upregulation. We propose that tick sRNA pathways control multiple aspects of immune response via RNAi and regulation of signaling pathways. Author summaryRNA-dependent RNA Polymerases (RdRPs) are essential for biogenesis of small regulatory RNAs (sRNAs) in many organisms such as plants and fungi, but its general importance in animals besides nematodes remains controversial because experimental evidence is lacking. By using a tick cell line, we demonstrate that RdRP-dependent sRNAs are abundantly expressed and tick RdRPs regulate gene expression. These results indicate that ticks have unexpectedly complex sRNA biogenesis pathways that are essential for proper gene regulation. Interestingly, we show that RdRP negatively regulates immune response by changing expression of a gene that is essential in an immunity-related signaling pathway. Because ticks are important vectors of human and animal pathogens, studying the novel tick sRNA pathways and their effects on immune signaling may lead to a better understanding of vector-virus interactions.

molecular biology↗

bioRxiv2021

Ancestral chromosomes for the Peronosporaceae inferred from a telomere-to-telomere genome assembly of Peronospora effusa.

We report the first telomere-to-telomere genome assembly for an oomycete. This assembly has extensive synteny with less complete genome assemblies of other oomycetes and will therefore serve as a reference genome for this taxon. Downy mildew disease of spinach, caused by the oomycete Peronospora effusa, causes major losses to spinach production. The 17 chromosomes of P. effusa were assembled telomere-to-telomere using Pacific Biosciences High Fidelity reads. Sixteen chromosomes are complete and gapless; Chromosome 15 contains one gap bridging the nucleolus organizer region. Putative centromeres were identified on all chromosomes. This new assembly enables a re-evaluation of the genomic composition of Peronospora spp.; the assembly was almost double the size and contained more repeat sequences than previously reported for any Peronospora spp. Genome fragments consistently under-represented in six previously reported assemblies of P. effusa typically encoded repeats. Some genes annotated as encoding effectors were organized into multigene clusters on several chromosomes. At least two effector-encoding genes were annotated on every chromosome. The intergenic distances between annotated genes were consistent with the two-speed genome hypothesis, with some effectors located in gene-sparse regions. The near-gapless assembly revealed apparent horizontal gene transfer from Ascomycete fungi. Gene order was highly conserved between P. effusa and the genetically oriented assembly of the oomycete Bremia lactucae. High levels of synteny were also detected with Phytophthora sojae. Many oomycete species may have similar chromosome organization; therefore, this genome assembly provides the foundation for genomic analyses of diverse oomycetes.

genomics↗

bioRxiv2021

Colonial choanoflagellate isolated from Mono Lake harbors a microbiome

Choanoflagellates offer key insights into bacterial influences on the origin and early evolution of animals. Here we report the isolation and characterization of a new colonial choanoflagellate species, Barroeca monosierra, that, unlike previously characterized species, harbors a microbiome. B. monosierra was isolated from Mono Lake, California and forms large spherical colonies that are more than an order of magnitude larger than those formed by the closely related Salpingoeca rosetta. By designing fluorescence in situ hybridization probes from metagenomic sequences, we found that B. monosierra colonies are colonized by members of the halotolerant and closely related Saccharospirillaceae and Oceanospirillaceae, as well as purple sulfur bacteria (Ectothiorhodospiraceae) and non-sulfur Rhodobacteraceae. This relatively simple microbiome in a close relative of animals presents a new experimental model for investigating the evolution of stable interactions among eukaryotes and bacteria. IMPORTANCEThe animals and bacteria of Mono Lake (California) have evolved diverse strategies for surviving the hypersaline, alkaline, arsenic-rich environment. We sought to investigate whether the closest living relatives of animals, the choanoflagellates, exist among the relatively limited diversity of organisms in Mono Lake. We repeatedly isolated members of a single species of choanoflagellate, which we have named Barroeca monosierra, suggesting that it is a stable and abundant part of the ecosystem. Characterization of B. monosierra revealed that it forms large spherical colonies that each contain a microbiome, providing an opportunity to investigate the evolution of stable physical associations between eukaryotes and bacteria.

microbiology↗

bioRxiv2021

A chloride efflux transporter OsBIRG1 regulates grain size and salt tolerance in rice

Grain size is determined by the number of cells and cell size of the grain. Regulation of grain size is crucial for improving crop yield. However, the genes and underlying molecular mechanisms controlling grain size remain elusive. Here we report a member of Detoxification efflux carrier (DTX)/Multidrug and Toxic Compound Extrusion (MATE) family transporter, BIG RICE GRAIN 1 (BIRG1), negatively regulates the grain size in rice. BIRG1 is highly expressed in reproductive organs and roots. In birg1 grain, the size of the outer parenchyma layer cells of spikelet hulls is noticeably larger but the cell number is not altered compared with that in the wild-type (WT) grain. When expressed in Xenopus oocytes, BIRG1 exhibits chloride efflux activity. In line with the role of BIRG1 in mediating chloride efflux, the birg1 mutant shows reduced tolerance to salt stress under which the chloride level is toxic. Moreover, the birg1 grains contain higher level of chloride compared to WT grains when grown under normal paddy field. The birg1 roots accumulate more chloride than those of WT under saline condition. Collectively, our findings suggest that BIRG1 functions as a chloride efflux transporter regulating grain size and salt tolerance via controlling chloride homeostasis in rice.

plant biology↗

bioRxiv2021

Potent neutralization antibodies induced by a recombinant trimeric Spike protein vaccine candidate containing PIKA adjuvant for COVID-19

Neutralizing antibodies are critical to prevent corona virus infection. The structures of immunogens to elicit most potent neutralization antibodies are still under investigation. Here we tested the immunogenicity of the trimeric, full length Spike protein with 2 proline mutations to preserve its prefusion conformation. Recombinant trimeric Spike protein expressed by CHO cells was used with polyI:C (PIKA) adjuvant to immunize mice by 0-7-14 day schedule. The results showed that Spike-specific antibody was induced at day 21 with titer of more than 50,000 in average as measured by direct binding to Spike protein. The titer of neutralization reached more than 1000 in average when tested by a pseudo-virus system, using monoclonal antibodies (40592-MM57 and 40591-MM43) with neutralizing IC50 at 1 g/ml as standards. Protein/peptide array showed that the antibodies induced by trimeric S protein vaccine bind similarly to natural infection with the receptor binding domain (RBD) as major immunodominant region. No linear epitopes were found in RBD, although several linear epitopes were found in C-terminal domain right after RBD, and heptad repeat regions. Our study supports the efficacy of recombinant trimeric Spike protein vaccine candidate for COVID-19, with excellent safety and readiness for storage and distribution in developing countries.

immunology↗

bioRxiv2020

A single dose, BCG-adjuvanted SARS-CoV-2 vaccine induces Th1-polarized immunity and high-titre neutralizing antibodies in mice

Global control of COVID-19 requires broadly accessible vaccines that are effective against SARS-CoV-2 variants. In this report, we exploit the immunostimulatory properties of bacille Calmette-Guerin (BCG), the existing tuberculosis vaccine, to deliver a vaccination regimen with potent SARS-CoV-2-specific protective immunity. Combination of BCG with a stabilized, trimeric form of SARS-CoV-2 spike antigen promoted rapid development of virus-specific IgG antibodies in the blood of vaccinated mice, that was further augmented by the addition of alum. This vaccine formulation, BCG:CoVac, induced high-titre SARS-CoV-2 neutralizing antibodies (NAbs) and Th1-biased cytokine release by vaccine-specific T cells, which correlated with the early emergence of T follicular helper cells in local lymph nodes and heightened levels of antigen-specific plasma B cells after vaccination. Vaccination of K18-hACE2 mice with a single dose of BCG:CoVac almost completely abrogated disease after SARS-CoV-2 challenge, with minimal inflammation and no detectable virus in the lungs of infected animals. Boosting BCG:CoVac-primed mice with a heterologous vaccine further increased SARS-CoV-2-specific antibody responses, which effectively neutralized B.1.1.7 and B.1.351 SARS-CoV-2 variants of concern. These findings demonstrate the potential for BCG-based vaccination to protect against major SARS-CoV-2 variants circulating globally.

microbiology↗

bioRxiv2020

The selfish nature in interpersonal exchange among adolescents: imposing the kind and submitting to the exploitative

Cooperation is essential for success in society. Research consistently showed that adolescents are less cooperative than adults, which is often attributed to underdeveloped mentalizing that limits their expectations of others. However, the internal computations underlying this reduced cooperation remain largely unexplored. This study compared cooperation between adolescents and adults using a repeated Prisoners Dilemma Game. Adolescents cooperated less than adults, particularly after their partners cooperation. Computational modeling revealed that adults increased their intrinsic reward for reciprocating when their partner continued cooperating, a pattern absent in adolescents. Both computational modeling and self-reported ratings showed that adolescents did not differ from adults in building expectations of their partners cooperation. Therefore, the reduced cooperation appears driven by a lower intrinsic reward for reciprocity, reflecting a stronger motive to prioritize self-interest, rather than a deficiency in predicting others cooperation in social learning. These findings provide insights into the developmental trajectory of cooperation from adolescence to adulthood.

animal behavior and cognition↗

bioRxiv2020

Crash landing of Vibrio cholerae by MSHA pili-assisted braking and anchoring in a viscous environment

Mannose-sensitive hemagglutinin (MSHA) pili and flagellum are critical for the surface attachment of Vibrio cholerae, the first step of V. cholerae colonization on host surfaces. However, the cell landing mechanism remains largely unknown, particularly in viscoelastic environments such as the mucus layers of intestines. Here, combining the cysteine-substitution-based labelling method with single-cell tracking techniques, we quantitatively characterized the landing of V. cholerae by directly observing both pili and flagellum of cells in a viscoelastic non-Newtonian solution consisting of 2% Luria-Bertani and 1% methylcellulose (LB+MC). The results show that MSHA pili are evenly distributed along the cell length and can stick to surfaces at any point along the filament. With such properties, MSHA pili are observed to act as a brake and anchor during cell landing which include three phases: running, lingering, and attaching. Importantly, loss of MSHA pili results in a more dramatic increase in mean path length in LB+MC than in 2% LB only or in 20% Ficoll solutions, indicating that the role of MSHA pili during cell landing is more apparent in viscoelastic non-Newtonian fluids than viscous Newtonian ones. Our work provides a detailed picture of the landing dynamics of V. cholerae under viscoelastic conditions, which can provide insights into ways to better control V. cholerae infections in real mucus-like environment.

microbiology↗

bioRxiv2020

Immunity-and-Matrix-Regulatory Cells Derived from Human Embryonic Stem Cells Safely and Effectively Treat Mouse Lung Injury and Fibrosis

Lung injury and fibrosis represent the most significant outcomes of severe and acute lung disorders, including COVID-19. However, there are still no effective drugs to treat lung injury and fibrosis. In this study, we report the generation of clinical-grade human embryonic stem cells (hESCs)-derived immunity- and matrix-regulatory cells (IMRCs) produced under good manufacturing practice (GMP) requirements, that can treat lung injury and fibrosis in vivo. We generate IMRCs by sequentially differentiating hESCs with serum-free reagents. IMRCs possess a unique gene expression profile distinct from umbilical cord mesenchymal stem cells (UCMSCs), such as higher levels of proliferative, immunomodulatory and anti-fibrotic genes. Moreover, intravenous delivery of IMRCs inhibits both pulmonary inflammation and fibrosis in mouse models of lung injury, and significantly improves the survival rate of the recipient mice in a dose-dependent manner, likely through paracrine regulatory mechanisms. IMRCs are superior to both primary UCMSCs and FDA-approved pirfenidone, with an excellent efficacy and safety profile in mice and monkeys. In light of public health crises involving pneumonia, acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), our findings suggest that IMRCs are ready for clinical trials on lung disorders.

cell biology↗

bioRxiv2020

Transcriptome-Wide Combinatorial RNA Structure Probing in Living Cells

RNA molecules can fold into complex structures and interact with trans-acting factors to control their biology. Recent methods have been focused on developing novel tools to measure RNA structure transcriptome-wide, but their utility to study and predict RNA-protein interactions or RNA processing has been limited thus far. Here, we extend these studies with the first transcriptomewide mapping method for cataloging RNA solvent accessibility, icLASER. By combining solvent accessibility (icLASER) with RNA flexibility (icSHAPE) data, we efficiently predict RNA-protein interactions transcriptome-wide and catalog RNA polyadenylation sites by RNA structure alone. These studies showcase the power of designing novel chemical approaches to studying RNA biology. Further, our study exemplifies merging complementary methods to measure RNA structure inside cells and its utility for predicting transcriptome-wide interactions that are critical for control of and regulation by RNA structure. We envision such approaches can be applied to studying different cell types or cells under varying conditions, using RNA structure and footprinting to characterize cellular interactions and processing involving RNA.

biochemistry↗

bioRxiv2020

Marine snow as a habitat for microbial mercury methylators in the Baltic Sea

Methylmercury (MeHg), a neurotoxic compound biomagnifying in aquatic food webs, can be a threat to human health via fish consumption. However, the composition and distribution of the microbial communities mediating the methylation of mercury (Hg) to MeHg in marine systems remain largely unknown. In order to fill this gap of knowledge, we used the Baltic Sea Reference Metagenome (BARM) dataset to study the distribution of the genes involved in Hg methylation (the hgcAB gene cluster). We determined the relative abundance of the hgcAB genes and their taxonomic identity in 81 brackish metagenomes that cover spatial, seasonal and redox variability in the Baltic Sea water. The hgcAB genes were predominantly detected in anoxic water, but some hgcAB genes were also detected in hypoxic and normoxic waters. Higher relative quantities of hgcAB genes were found in metagenomes from marine snow compared to free-living communities in anoxic water, suggesting that marine snow are hotspot habitats for Hg methylators in oxygen-depleted seawater. Phylogenetic analysis identified well-characterized Hg methylators such as Deltaproteobacteria in oxygen-depleted water, but also uncovered Hg methylators within the Spirochaetes and Lentisphaerae phyla. Altogether, our work unveils the diversity of the microorganisms mediating MeHg production in the Baltic Sea and pinpoint the ecological niches of these microorganisms within the marine water column.

microbiology↗

bioRxiv2020

Mucosal vaccination with CysVac2/Advax induces Th17 lung-resident CD4+ T cells and interleukin-17-dependant protection against Mycobacterium tuberculosis infection

The development of effective vaccines against bacterial lung infections requires the induction of protective, pathogen-specific immune responses without deleterious inflammation within the pulmonary environment. Here, we made use of a polysaccharide-adjuvanted vaccine approach to elicit resident pulmonary T cells to protect against aerosol Mycobacterium tuberculosis infection. Intratracheal administration of the multistage fusion protein CysVac2 and the delta-inulin adjuvant Advax (formulated with a TLR9 agonist) provided superior protection against aerosol M. tuberculosis infection in mice, compared to parenteral delivery. Surprisingly, removal of the TLR9 agonist did not impact vaccine protection despite a reduction in cytokine-secreting T cell subsets, particularly CD4+ IFN-{gamma}+IL-2+TNF+ multifunctional T cells. CysVac2/Advax-mediated protection was associated with the induction of lung-resident, antigen-specific memory CD4+ T cells that expressed IL-17 and ROR{gamma}t, the master transcriptional regulator of Th17 differentiation. IL-17 was identified as a key mediator of vaccine efficacy, with blocking of IL-17 during M. tuberculosis challenge reducing phagocyte influx, suppressing priming of pathogen-specific CD4+ T cells in local lymph nodes and ablating vaccine-induced protection. These findings suggest that tuberculosis vaccines such as CysVac2/Advax that are capable of eliciting Th17 lung-resident memory T cells are promising candidates for progression to human trials. ImportanceMycobacterium tuberculosis, the causative agent of tuberculosis (TB), kills more individuals each year than any other single pathogen. The only approved vaccine, BCG, administered intradermally, is unreliable in protecting against pulmonary TB, therefore a more effective vaccine is critical for global control of the disease. Vaccination in the lung would be a rational way of inducing a local memory immune response to TB, however vaccine platforms would need to deliver antigens to delicate mucosal surfaces without inducing deleterious inflammatory responses. We developed a safe mucosal vaccine which induced protection against TB lung infection in mice by inducing high levels of lung-resident T cells expressing the cytokine IL-17. Removal of IL-17 limited the influx of phagocytic cells to the lung and completely ablated protection afforded by the vaccine. This study provides new insights into mechanisms of protection against M. tuberculosis and provides a promising candidate to protect against TB in humans.

immunology↗

bioRxiv2020

Microbial redox activity mediated anaerobic pyrite oxidation under circumneutral conditions

In modern Earth, anaerobic pyrite oxidation under circumneutral conditions also has great impact on the fate of nitrate in aquifers and sediments, as well as the transportation of toxic metals. However, the mechanism of how microbes mediated this process is still being debated. Electrochemical analysis on pyrite cubic electrode showed that, its oxidation threshold under anaerobic circumneutral conditions (ca. 200 mV) was much lower than that at aerobic acidic conditions (ca. 650 mV), implying possible direct pyrite oxidation by high redox potential cellular components. Sole substrate (pyrite) microbial enrichment cultures with EDTA addition showed higher oxidation rate (0.092 d-1) than that of EDTA-free cultures (0.019 d-1), suggesting that ligands producing pathway was much preferred by microbes than maintaining acidic micro-environments. This hypothesis was supported by amplicon and metagenomic sequencing data, which demonstrated discrepant bacteria involving iron-sulfur oxidation and metabolic potentials in cultures with/without EDTA addition. A concept model was proposed based on experimental data considering different reaction stages and microbial communities. The results shed lights on the potential interactions between microbes and pyrite, which may serve as a model for explaining subsurface pyrite oxidation and optimizing anaerobic pyrite oxidation-based pollutant removal processes. TOC art O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=99 SRC="FIGDIR/small/952168v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@14c7a01org.highwire.dtl.DTLVardef@1de10bdorg.highwire.dtl.DTLVardef@1ceb4dorg.highwire.dtl.DTLVardef@9c27fc_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2020

Genetic diversity of the spinach downy mildew pathogen based on hierarchical sampling

Downy mildew, caused by the obligate oomycete pathogen Peronospora effusa, is the most economically important disease of spinach. In the past 30 years, 14 new races and 13 strains with novel virulence have been identified. However, the mechanism(s) driving the rapid evolution of virulence remains unknown. To understand reproductive strategies potentially driving the emergence of new races in P. effusa, 67 composite isolates (a collection of symptomatic leaves from a single cultivar grown in a defined area) of P. effusa obtained from 13 states between 2010 and 2018 were used to analyze the population genetic diversity hierarchically. Genotypes at 33 SNP loci of 719 lesions from these 67 isolates were determined by targeted sequencing. Diversity was then evaluated among individual lesions within the composite isolates, between isolates, host cultivars, geographic locations, and years of isolates collected. A total of 380 genotypes were identified from 719 individual lesions. Of the 380 genotypes, 350 (92%) were unique while the most common genotype was identified in 110 lesions of 16 isolates collected from 13 cultivars from CA and AZ in 2016. Variation within composite isolates ranged from none (a single genotype among lesions from a composite isolate) to 38 unique genotypes recovered from 39 lesions of a composite isolate. An index of association analysis suggested asexual (clonal) and sexual reproduction play important roles in population structure. Based on discriminant analysis of principal components, four distinct subpopulations were identified. Host cultivar, origin, and time of collection had an effect on population differentiation, and genotypes specific to a certain location or collection period were identified. Some subpopulations were unique to certain areas, and were only detected after 2014-2016. The co-existence of sexual and asexual reproduction strategies may partially explain the rapid emergence and spread of new races and novel strains of P. effusa.

microbiology↗

bioRxiv2019

An antibody drug conjugate targeting a GSTA glycosite-signature epitope of mucin1 expressed by non-small cell lung cancer

BackgroundAntibodies targeting abnormally glycosylated proteins have been ineffective in treating cancer. Antibody-drug conjugates are emerging as an efficient option, which allow specific delivery of drugs into tumors. We and others have dissected the abnormally glycosylated tandem repeat region of MUC1 glycoprotein as three site-specific glycosylated neoantigen peptide motifs (PDTR, GSTA, GVTS) for monoclonal antibody binding. MethodsInternalization of monoclonal antibodies was studied by immunofluorescence staining and colocalization with lysosomal markers in live cells. Antibody positivity in tumor and peritumoral tissue samples were studied by immunohistochemistry. The efficacy of anti-MUC1 ADCs were evaluated with various cancer cell lines and mouse tumor xenograft model. ResultsWe describe an anti-MUC1 ADC by conjugating GSTA neoantigen-specific 16A with monomethyl auristatin E (MMAE). 16A-MMAE showed potent antitumoral efficacy with IC50 ranging from 0.2 to 49.4 nM toward multiple types of cancer cells. In vivo, 16A-MMAE showed dose-dependent inhibition of tumor growth in mouse xenograft of NCI-H838 NSCLC cell line, with minimum effective dose at 1 mg/kg. At the dose of 3 mg/kg, 16A-MMAE did not cause significant toxicity in a transgenic mouse expressing human MUC1. ConclusionsThe high antitumoral efficacy of 16A-MMAE suggest that aberrant glycosylated MUC1 neoantigen is a target with high positivity in multiple cancer types for ADC development. Personalized therapy may be achieved by development of glycosite-specific antibody-drug conjugates.

pharmacology and toxicology↗

bioRxiv2019

Development of SSR markers related to seed storability traits in maize subjected to artificial seed aging conditions

Seed storability is an important and complex agronomic trait in maize because annual seed production considerably exceeds consumption. The viability of seeds decreases over time, even when stored at low temperature, until seeds finally lose viability. In our previous study, two inbred lines with significantly different storability, Dong156 with high storage tolerance and Dong237 with low storage tolerance, were selected over six years using a natural seed aging test. In the present study, an F2:3 population and a RIL (recombinant inbred line) population were constructed from these two inbred lines and used to map QTL (quantitative trait loci) with SSR (simple sequence repeat) markers. A phenotypic index of traits related to seed storability that includes germination rate, germination potential, a germination index, a vigor index, seedling weight, and seedling length was generated using the results of an artificial aging treatment. Two consistent regions, cQTL-7 on chromosome 7 and cQTL-10 on chromosome 10, were identified by comparing QTL analysis results from these two populations. After genotyping SSR markers in these two regions, cQTL-7 was remapped to between umc1671 and phi328175 in a 7.97-Mb region, and cQTL-10 was remapped to between umc1648 and phi050 in a 39.15-Mb region. Four SSR markers linked to cQTL-7 and cQTL-10, including umc1671, phi328175, umc1648, and phi050, were identified using a Chi-squared test. The combined selection efficiency of these four markers was 83.94% in 85 RIL lines with high storability, and marker umc1648 exhibited the highest efficiency value of 88.89%. These results indicated that the four SSR markers developed in this study could be used for selection of maize germplasm with high seed storability.

plant biology↗