Biology subjects

Lv, Y.

Publications and source records attributed to Lv, Y..

At least 37 records · Page 2Linked to original sources

bioRxiv2023

Discovery of a Novel Chemotype as DYRK1A Inhibitors against Alzheimer's disease: Computational Modeling and Biological Evaluation

Dual specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) plays an essential role in tau and A{beta} pathology closely related to Alzheimers disease (AD). Accumulative evidence has demonstrated DYRK1A inhibition is able to reduce the pathological features of AD. Nevertheless, there is no approved DYRK1A inhibitors for clinical use as anti-AD drugs. This is somewhat the lack of effective and safe chemotypes of DYRK1A inhibitors. To address this issue, we carried out in silico screening, in vitro assays and in vivo efficacy evaluation with the aim to discover a new class of DYRK1A inhibitors for potential treatment of AD. By in silico screening, we selected and purchased 16 potential DYRK1A inhibitors from the Specs chemical library. Among them, compound Q17 (Specs ID: AO-476/40829177) potently inhibited DYRK1A. The hydrogen bonds between compound Q17 and each of three amino acid residues named GLU239, LEU241 and LYS188, were uncovered by molecular docking and molecular dynamics simulation. The cell-based assays showed that compound Q17 could protect SH-SY5Y cells from okadaic acid (OA)-induced injury by targeting DYRK1A. More importantly, compound Q17 significantly improved cognitive dysfunction in 3xTg-AD mice, ameliorated pathological changes, and reduced the expression of DYRK1A, GSK-3{beta} and GSK-3{beta} (pSer9), attenuated tau hyperphosphorylation and A{beta} deposition as well. In summary, our computational modeling strategy is effective to identify novel chemotypes of DYRK1A inhibitors with great potential to treat AD, and the identified compound Q17 in this study is worthy of further study. Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=182 SRC="FIGDIR/small/565431v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@75abecorg.highwire.dtl.DTLVardef@16a3611org.highwire.dtl.DTLVardef@39aeborg.highwire.dtl.DTLVardef@afc8ab_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2023

New insights into tissue-specific responses and interactive characteristics of crop-microbe "One Health" system to soil chromium and ofloxacin pollution

This study firstly investigated the tissue-specific responses and interactive characteristics of the crop-microbe system to co-pollution with ofloxacin (OFL) and chromium (Cr) in soil. The results emphasized the hormesis effect induced by low-dose OFL (1 mg L-1) on ginger plants subjected to soil Cr stress. However, high-dose OFL (100 mg L-1) and Cr co-stressed plants exhibited reduced growth, root activity, antioxidant enzyme activities and photosynthesis-fluorescence performances, while the reactive oxygen species (ROS) reflected by O2{middle dot}- and H2O2 significantly increased up to 43.34% and 78.63%, respectively, compared to other treatments. In addition, high-throughput sequencing indicated that OFL influenced rhizosphere microbial diversity, composition, and evolution, favoring Proteobacteria proliferation under co-pollution. Meanwhile, root exudate patterns shifted, with humic-like exudates, potentially interacting with pollutants and microbes. Notably, enrichments of antibiotic resistance gene (qnrS) in edible rhizome and potential pathogenic bacteria in ginger rhizosphere were observed under OFL and Cr co-pollution, raising environmental and food chain concerns. Through structural equation modeling, we quantitatively established correlations within soil-crop-microbe factors, emphasizing their interconnected nature. Overall, this study sheds light on the complex responses of the crop-microbe system to OFL and Cr co-pollution, highlighting the importance of understanding pollutant interactions for enhancing plant resilience and mitigating environmental risks. HighlightsO_LIRevealed a hormesis from low-dose OFL on Cr-polluted ginger, enhancing resilience. C_LIO_LIRhizosphere microbial composition shift under co-pollution, favoring Proteobacteria. C_LIO_LIqnrS and potential pathogens increased under co-pollution, posing food chain risks. C_LIO_LIStructural equation modeling quantified correlations in soil- crop-microbe factors. C_LIO_LIClarified crop-microbe "One Health" interactions role under Cr & OFL co-pollution. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=128 SRC="FIGDIR/small/561380v1_ufig1.gif" ALT="Figure 1"> View larger version (61K): org.highwire.dtl.DTLVardef@bd3d20org.highwire.dtl.DTLVardef@1f8024eorg.highwire.dtl.DTLVardef@15f6154org.highwire.dtl.DTLVardef@ef0aeb_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2023

Characterization of the Complete Chloroplast Genome Sequences and Phylogenetic Relationships of Four Oil-Seed Camellia spp. and related taxa

Some species in the Sect. Oleifera of the genus Camellia L. known as oil-seed camellia because of their high oil content and economic value. Additional studies aimed at clarifying the phylogenetic relationships and chloroplast genomes of Camellia species are needed to hybridization, as well as improve the breeding, selection and interspecific hybridization of Camellia species. The complete chloroplast genomes (cpDNA) of the four oil-seed camellia species C. semiserrata, C. meiocarpa, C. suaveolens, and C. osmantha were resequenced to clarify their interspecific relationships. These cpDNA had typical tetrad structures, and they were highly conserved in various structural features. The total lengths of the cpDNA ranged from 156,965 to 157,018 bp, and 134 genes were annotated, including 88 protein-coding genes, 37 transfer RNA genes, and 8 messenger RNA genes. The average GC content of these genomes was 37.3%. The codons with the highest and lowest codon usage bias were UUA (which codes for leucine) and AGC (which codes for serine), respectively. The number of simple sequences repeats of the four Camelia species ranged from 38 to 40. Mononucleotide repeats were the most common repeat type, followed by tetranucleotide, trinucleotide, and hexanucleotide repeats. Our phylogenetic analysis of cpDNA, coupled with the results of previous ploidy analyses and artificial interspecific hybridization, revealed that C. semiserrata was most closely related to C. azalea, C. suaveolens was most closely related to C. gauchowensis, C. osmantha was most closely related to C. vietnamensis, and C. meiocarpa was most closely related to C. oleifera. The phylogenetic relationships between oil-seed camellia species with high oil content and economic value were characterized. Our analysis of the cpDNA provided new insights that will aid the use of artificial distant hybridization in camellia breeding programs.

genomics↗

bioRxiv2023

A conserved N-terminal motif of CUL3 mediates assembly and licenses E3 ligase activation of CRL3KLHL22

The CUL3-RING E3 ubiquitin ligases (CRL3s) play an essential role in response to extracellular nutrition and stress stimuli. The ubiquitin ligase function of CRL3s is activated through E3-E3 dimerization. However, how and why such a dimeric assembly is required for its ligase activity remains elusive. Here, we report the cryo-EM structure of the dimeric CRL3KLHL22 complex and reveal a conserved N-terminal motif in CUL3 that mediates the dimerization assembly and licenses the activation of CRL3KLHL22. Deletion of the CUL3 N-terminal motif leads to non-stochiometric assembly and impairs E3 activity of both CRL3KLHL22 and several other CRL3s. In addition, we found that the dynamics of dimeric E3-E3 superassembly generates a variable ubiquitination zone, potentially facilitating substrate recognition and ubiquitination. These findings demonstrate a CUL3 N-terminal motif-dependent E3-E3 superassembly mechanism and provide insights into the assembly and activation of CRL3s.

molecular biology↗

bioRxiv2023

LSM14B is essential for mitochondrial clustering in the oocyte meiosis

As oocyte meiotic maturation, they undergo two successive meiotic M phases, notably lacking an intervening interphase phase. During these M phases, oocytes remain transcriptionally quiescent, and we now know that "translational repressed mRNAs" are stored in a structure called the mitochondria associated ribonucleoprotein domain (MARDO). LSM14B is one of the abundant proteins of MARDO, and is predicted to bind mRNA, but its function(s) remain elusive. Here, we demonstrate that LSM14B functions to promote MARDO assembly in mouse oocytes. We also found that LSM14B knockout female mice are infertile, and show that the knockout oocytes fail to enter meiosis II, instead entering an aberrant interphase-like stage. Finally, we show that the failure of oocyte maturation results from decreased expression of Cyclin B1. Our study has revealed that the RNA-binding protein LSM14B modulates MARDO assembly and is essential for oocyte meiotic maturation.

developmental biology↗

bioRxiv2023

Discovery of microRNA-derived RNAs and proteins in human cells

MicroRNAs (miRNAs) are short noncoding RNAs that can regulate gene expression through the binding of their 5-ends to mRNAs. However, the biological effects of miRNA binding via their 3-ends remain unclear. Here, we discover that the exact reverse pairing of the 3-ends of miRNAs or miRNA-like RNAs, collectively termed microsized RNAs (msRNAs), with template RNAs can initiate the production of msRNA-derived RNAs (msdRs), which can subsequently be translated into polypeptides (msdPs). Using 2,632 human msRNAs from miRBase, 11,121 msdRs and 1,239 msdPs were predicted based on a 15-nucleotide pairing threshold, and the presence of representative msdRs and msdPs was confirmed in human cells. Of clinical relevance, msdP0188 is highly expressed in human lung and breast cancers, and its corresponding msRNAs and msdRs represent novel anti-cancer targets. Notably, inhibiting telomerase reverse transcriptase, a putative RNA-dependent RNA polymerase identified by bioinformatic screening, led to reduced levels of msdP0188 in human cancer cells. Our findings reveal a novel "msRNA [->] msdR [->] msdP" axis, expanding the classical central dogma and predicting many previously unrecognized RNAs and polypeptides with potential biological functions in human cells and other systems.

cell biology↗

bioRxiv2023

Single-Soma Deep RNA sequencing of Human DRG Neurons Reveals Novel Molecular and Cellular Mechanisms Underlying Somatosensation

The versatility of somatosensation arises from heterogeneous dorsal root ganglion (DRG) neurons. However, soma transcriptomes of individual human DRG (hDRG) neurons - critical information to decipher their functions - are lacking due to technical difficulties. Here, we developed a novel approach to isolate individual hDRG neuron somas for deep RNA sequencing (RNA-seq). On average, >9,000 unique genes per neuron were detected, and 16 neuronal types were identified. Cross-species analyses revealed remarkable divergence among pain-sensing neurons and the existence of human-specific nociceptor types. Our deep RNA-seq dataset was especially powerful for providing insight into the molecular mechanisms underlying human somatosensation and identifying high potential novel drug targets. Our dataset also guided the selection of molecular markers to visualize different types of human afferents and the discovery of novel functional properties using single-cell in vivo electrophysiological recordings. In summary, by employing a novel soma sequencing method, we generated an unprecedented hDRG neuron atlas, providing new insights into human somatosensation, establishing a critical foundation for translational work, and clarifying human species-specific properties.

neuroscience↗

bioRxiv2023

The landscape of m1A modification and its posttranscriptional regulatory functions in primary neurons

Cerebral ischaemia-reperfusion injury, during which neurons undergo oxygen-glucose deprivation/reoxygenation (OGD/R), is a notable pathological process in many neurological diseases. N1-methyladenosine (m1A) is an RNA modification that can affect gene expression and RNA stability. The m1A landscape and potential functions of m1A modification in neurons remain poorly understood. We explored RNA (mRNA, lncRNA, and circRNA) m1A modification in normal and OGD/R-treated neurons and the effect of m1A on diverse RNAs. We investigated the m1A landscape in primary neurons, identified m1A-modified RNAs, and found that OGD/R increased the number of m1A RNAs. m1A modification might also affect the regulatory mechanisms of noncoding RNAs, e.g., lncRNA-RBP interactions and circRNA translation. We showed that m1A modification mediates the circRNA/lncRNA-miRNA-mRNA ceRNA mechanism and that 3UTR methylation of mRNAs can hinder miRNA-mRNA binding. Three methylation patterns were identified, and genes with different patterns had intrinsic mechanisms with potential m1A-regulatory specificity. Systematic analysis of the m1A landscape in normal and OGD/R neurons lays a critical foundation for understanding RNA methylation and provides new perspectives and a theoretical basis for treating and developing drugs for OGD/R pathology-related diseases.

neuroscience↗

bioRxiv2022

Long-read genome assemblies reveals a cis-regulatory landscape associated with phenotypic divergence in two sister Siniperca fishes

BackgroundDissecting the genetic basis of variation in the regulation of gene expression is essential for understanding phenotypic evolution. Structural variants intersecting the cis-regulatory elements are found to cause gene expression variation in several developmental genes, resulting in morphological divergence between species. Due to the difficulty of identifying structural variants accurately across the genome, a comprehensive study of impacts of structural variants in cis-regulatory divergence of closely related species, especially fish species, is still scarce. Recently identified broad H3K4me3 domains are essential for the regulation of genes involved in several biological processes. However, the role of broad H3K4me3 domains in phenotypic divergence remain poorly understood. Siniperca chuatsi and S. scherzeri are two closely related fish species diverge in several phenotypic traits, making them an ideal model to study cis-regulatory evolution in closely related species. ResultsWe generated chromosome-level genomes of S. chuatsi and S. scherzeri. The evolutionary histories of S. chuatsi and S. scherzeri were studied by inferring the dynamic changes in the ancestral population sizes. The genetic basis of adaptation in S. chuatsi and S. scherzeri was dissected by performing gene family expansion and contraction analysis and identifying positively selected genes (PSGs). To investigate the role of SVs in cis-regulatory divergence of closely related fish species, we identified high-quality SVs between S. chuatsi and S. scherzeri, as well as H3K27ac and H3K4me3 domains. Integrated analysis revealed that cis-regulatory divergence caused by SVs played an essential role in the differentiation of metabolism, skin pigmentation, and immunity between S. chuatsi and S. scherzeri. Additionally, divergent broad H3K4me3 domains were found to mostly associate with cancer-related genes in S. chuatsi and S. scherzeri and contribute to their phenotypic divergence. ConclusionsOur analysis reveals SVs play an essential role in cis-regulatory variation between the two sister fish species, which in turn contributes to their phenotypic divergence. The divergence of broad H3K4me3 domains contributes to phenotypic divergence between closely related species. Additionally, the association of broad H3K4me3 domains and cancer-related genes has an ancient origin.

genomics↗

bioRxiv2022

The Slingshot phosphatase 2 is required for acrosome biogenesis during spermatogenesis in mice

The acrosome is a membranous organelle positioned in the anterior portion of sperm head and is essential for male fertility. Acrosome biogenesis requires the dynamic cytoskeletal shuttling of vesicles towards nascent acrosome which is regulated by a series of accessory proteins. However, much remains unknown about the molecular basis underlying this process. Here, we generated Ssh2 knock-out (KO) mice and show that Slingshot phosphatase 2 (SSH2), a regulator of actin remodeling, is essential for acrosome biogenesis and male fertility. In Ssh2 KO males, spermatogenesis was arrested at the early spermatid stage with enhanced germ cell apoptosis and the impaired acrosome biogenesis was characterized by defective transport/fusion of proacrosomal vesicles. Moreover, disorganized F-actin structures accompanied by excessive phosphorylation of COFILIN were observed in testes of Ssh2 KO mice. Collectively, our data reveal a modulatory role for SSH2 in acrosome biogenesis through COFILIN-mediated actin remodeling and the indispensability of this phosphatase in male fertility in mice.

developmental biology↗

bioRxiv2022

Invigorating human MSCs for transplantation therapy via Nrf2/DKK1 co- stimulation in a mice acute-on-chronic liver failure model

Boosting stem cell resilience against an extrinsically harsh recipient environment is critical to therapeutic efficiency of stem cell-based transplantation innovations in liver disease contexts. We aimed to establish the efficacy of a transient plasmid-based preconditioning strategy to boost mesenchymal stromal cells (MSCs) capacity for anti-inflammation/antioxidant defense and paracrine actions on recipient hepatocytes. In MSCs, the master antioxidant regulator Nrf2 was found to bind directly to the antioxidant response element in the DKK1 promoter region. Activation of Nrf2 and DKK1 enhanced the anti-stress capacities of MSCs in vitro. In an acute-on-chronic liver failure (ACLF) murine model, transient co-overexpression of Nrf2 and DKK1 via plasmid transfection markedly improved MSC resilience against inflammatory and oxidative assaults, boosted MSC transplantation efficacy and promoted recipient liver regeneration because of a shift from the activation of the anti-regenerative IFN-{gamma}/STAT1 pathway to the pro-regenerative IL-6/STAT3 pathway in the liver. Moreover, specific ablation of DKK1 receptor CKAP4 but not LRP6 in recipient hepatocytes nullified therapeutic benefits from MSC transplantation. In long-term observations, tumorigenicity was undetected in mice following transplantation of such transiently preconditioned MCSs. In conclusion, co-stimulation of Nrf2/DKK1 signaling decisively and safely improves the efficacy of human MSC-based therapies in mouse ACLF models through apparently CKAP4-dependent paracrine mechanisms.

molecular biology↗

bioRxiv2022

Characteristics of N6-methyladenosine modification during sexual reproduction of Chlamydomonas reinhardtii

The unicellular green alga Chlamydomonas reinhardtii (referred to as Chlamydomonas throughout) is an ideal model organism which possesses both plant and animal attribute for studying the fundamental processes such as photosynthesis, sexual reproduction and life cycle etc. N6-methyladenosine (m6A) is the most prevalent mRNA modification and plays important roles during sexual reproduction in animals and plants. However, the pattern and function of m6A modification during Chlamydomonas sexual reproduction is still unknown. Here, we performed transcriptome and MeRIP sequencing on the six samples from different stages during sexual reproduction of Chlamydomonas life cycle. The results showed that m6A occurs widely at the main motif of UGKAM (K= U/G, M= A/C) in Chlamydomonas mRNA. Moreover, m6A peak in Chlamydomonas mRNA is mainly enriched in the 3UTR region and negatively correlated with the abundance of the transcripts at each stage. Especially, genes in microtubule-associated pathway showed a significant negative correlation between gene expression level and m6A level, indicating the influences of m6A modification on sexual reproduction and life cycle of Chlamydomonas through regulating microtubule-based movement. In summary, our findings first demonstrate the distributions and the functions of m6A modification in Chlamydomonas and provide new insights into the understandings of m6A modification in the process of sexual reproduction in other plant organisms evolutionarily.

plant biology↗

bioRxiv2022

The infiltration pattern of microenvironmental cells and different immune escape mechanisms in colorectal cancer

BackgroundThe tumour microenvironment (TME) plays a crucial role in tumour progression and metastasis. However, the infiltration pattern of TME cells in CRC samples and the immune escape mechanism underneath have not been studied sufficiently. MethodsTranscriptomic data from public datasets were retrieved online. In total, 1802 samples from the microarray dataset and 619 samples from the TCGA dataset were enrolled. The ssGSEA algorithm and unsupervised clustering were used for TME cells infiltration speculation and infiltration pattern recognition. ResultsCRC samples can be classified into three distinct TME cell subtypes. Subtype 1, the immune-active subtype, was characterised by high infiltration of activated adaptive immune cells. Subtype 2, the immune-desert subtype, featured high tumour purity and low infiltration of immune and stromal cells. And subtype 3, stroma-rich subtype, had high infiltration of stromal cells. The stroma-rich subtype conferred a significantly worse prognosis. Three subtypes had different immune escape mechanisms. The immune-active subtype has the highest immune checkpoint expression level. In comparison, the immune-desert subtype had the lowest immunogenicity and the defective antigen presentation. And the stroma-rich subtype lacked activated immune cells. ConclusionsDistinct TME cell subtypes and immune escape mechanisms may provide inspiration and direction for further researches on CRC immunotherapy.

cancer biology↗

bioRxiv2022

Harringtonine has the effects of double blocking SARS-CoV-2 membrane fusion

Fusion with host cell membrane is the main mechanism of infection of SARS-CoV-2. Here, we propose a new strategy to double block SARS-CoV-2 membrane fusion by using Harringtonine (HT), a small-molecule antagonist. By using cell membrane chromatography (CMC), we found that HT specifically targeted the SARS-CoV-2 S protein and host cell TMPRSS2, and then confirmed that HT can inhibit pseudotyped virus membrane fusion. Furthermore, HT successfully blocked SARS-CoV-2 infection, especially in the delta and Omicron mutant. Since HT is a small-molecule antagonist, it is minimally affected by the continuous variation of SARS-CoV-2. Our findings show that HT is a potential small-molecule antagonist with a new mechanism of action against SARS-CoV-2 infection, and thus HT mainly targets the S protein, and thus, greatly reduces the damage of the S proteins autotoxicity to the organ system, has promising advantages in the clinical treatment of COVID-19.

pharmacology and toxicology↗

bioRxiv2022

Single cell sequencing reveals microglia induced angiogenesis by specific subsets of endothelial cells following spinal cord injury

Spinal cord injury (SCI) results in dynamic alterations of the microenvironment at the lesion site, which inevitably leads to neuron degeneration and functional deficits. The prominent deterioration of the milieu, derived from the destruction of spinal vascular system, not only activates innate immunity but also makes cells in the lesion lose nutrient supports. Limited endogenous angiogenesis happens after SCI, but the cell events at the lesion site underpinning this process have not been delineated so far. Here, we conducted single-cell RNA sequencing (scRNA-seq) of tissues in the spinal lesion at different time points after rat SCI. After performing clustering and cell-type identification, we focused on the vascular endothelial cells (ECs), which play a pivot role in angiogenesis, and drew a comprehensive cellular and molecular atlas for endogenous angiogenesis after SCI. We found that microglia and macrophage promote endogenous angiogenesis by regulating EC subsets through SPP1 and IGF1 signal pathways. Our results indicated that immune cells promotes angiogenesis by the regulation of specific cell subsets of vascular ECs, which provides new clues for the development of interventions for SCI.

neuroscience↗

bioRxiv2021

A spatiotemporal steroidogenic regulatory network in human fetal adrenal glands and gonads

Human fetal adrenal glands produce substantial amounts of dehydroepiandrosterone (DHEA), which is one of the most important precursors of sex hormones. However, the underlying biological mechanism remains largely unknown. Herein, we sequenced human fetal adrenal glands and gonads from 7 to 14 GW via the 10x Genomics single-cell transcriptome techniques and reconstructed their location information by Spatial Transcriptome, conducted COOL-seq for the MC2R+ inner zone steroidogenic cells during the time window of sex differentiation (8-12GW). We found that relative to gonads, adrenal glands begin to synthesize steroids early. The coordination among steroidogenic cells and multiple nonsteroidogenic cells promotes adrenal cortex construction and steroid synthesis. Notably, during the time window of sex differentiation (8-12 GW), key enzyme gene expression shifts to accelerate DHEA synthesis in males and cortisol synthesis in females. Furthermore, high SST+ expressions in the adrenal gland and testis amplify androgen synthesis in males. Our research highlights the robustness of the action of fetal adrenal glands on gonads to modify the process of sexual differentiation.

systems biology↗

bioRxiv2021

Annulment of antagonism shifts properties that are beneficial to plants in two-member consortia of Bacillus velezensis

Bacillus spp. strains that are beneficial to plants are widely used in commercial biofertilizers and biocontrol agents for sustainable agriculture. Generally, functional Bacillus strains are applied as single strain communities since the principles of synthetic microbial consortia constructed with Bacillus strains remain largely unclear. Here, we demonstrated that the mutual compatibility directly affects the survival and function of two-member consortia composed of B. velezensis SQR9 and FZB42 in the rhizosphere. A mutation in the global regulator Spo0A of SQR9 markedly reduced the boundary phenotype with wild-type FZB42, and the combined use of the SQR9{triangleup}spo0A mutant and FZB42 improved biofilm formation, root colonization and the production of secondary metabolites that are beneficial to plants. We further confirmed the correlation between the swarm discrimination phenotype between the two consortia members and the effects that are beneficial to plants in a greenhouse experiment. Our results provide evidence that social interactions among bacteria could be an influencing factor in achieving a desired community-level function. IMPORTANCEBacillus velezensis is one of the most widely applied bacteria in biofertilizers in China and Europe. Additionally, the molecular mechanisms of plant growth promotion and disease suppression by representative model strains are well established, such as B. velezensis SQR9 and FZB42. However, it remains extremely challenging to design efficient consortia based on these model strains. Here, we showed that swarm discrimination phenotype is one of the major determinants affects the performance of two-member Bacillus consortia in vitro and in the rhizosphere. Deletion in global regulatory gene spo0A of SQR9 reduced the strength of boundary formation with FZB42, result in the improved plant growth promotion performance of dual consortium. This knowledge provides new insights into efficient probiotics consortia design in Bacillus.

microbiology↗

bioRxiv2021

Rod-genesis driven by mafba in an nrl knockout zebrafish model with altered photoreceptor compositions and progressive retinal degeneration

The neural retina leucine zipper (NRL) is an essential gene for the fate determination and differentiation of rod photoreceptors in mammals. Mutations in NRL have been associated with autosomal recessive enhanced S-cone syndrome and autosomal dominant retinitis pigmentosa. However, the exact role of Nrl in regulating the development and maintenance of photoreceptors in zebrafish, a popular animal model used for retinal degeneration and regeneration studies, has not been fully determined. In this study, we generated an nrl knockout zebrafish model by CRISPR-Cas9 technology and observed a surprising phenotype characterized by the reduction but not total elimination of rods and the over-grown of green-cones. By tracing the developmental process of rods, we discovered two waves of rod genesis in zebrafish, emerging at the embryonic stage with an nrl-dependent pattern and the post-embryonic stage with an nrl-independent pattern, respectively. Through bulk and single-cell RNA sequencing, we constructed the gene expression profiles for the whole retinal tissues and each of the retinal cell types in WT and nrl knockout zebrafish. We detected the rod/green-cone intermediate photoreceptors in nrl knockout zebrafish, suggesting that there may be a kind of rod/green-cone bipotent precursors and its fate choice between rod and green-cone is controlled by nrl. Besides, we identified the mafba gene as a novel regulator for nrl-independent rods, based on the cell-type-specific expression pattern and the retinal phenotype of nrl/mafba double knockout zebrafish. Furthermore, the altered photoreceptor compositions and abnormal gene expression caused progressive retinal degeneration and subsequent regeneration in nrl knockout zebrafish. Our work revealed a novel function of mafba gene in rod development and established a more suitable model for the developmental processes and regulatory mechanisms of rod and green-cone photoreceptors in zebrafish. Author SummaryVision is mediated by two types of light-sensing cells named rod and cone photoreceptors in animal eyes. Abnormal generation, dysfunction or death of photoreceptor cells can all cause irreversible vision problems. NRL is the most important gene for the occurrence and function of rod cells in mice and humans. Surprisingly, we found that in zebrafish, a popular animal model used for mimicking human diseases and testing treatments, there are two types of rod cells and breaking the function of nrl gene only affects the generation of rod cells at the embryonic stage but not the juvenile and adult stages. The rod cells produced later are proved to be driven by the mafba gene, which has not been reported to play a role in rod cells. In addition to the reduction of rod cells, deletion of nrl also results in the occurrence of rod/green-cone hybrid cells and the increasing number of green-cones. The combination of changes at cellular and molecular levels finally lead to a disease condition named retinal degeneration. These findings add new knowledge to the research field and highlight the conserved and species-specific regulatory mechanisms of photoreceptor development and maintenance.

genetics↗