Biology subjects

Hu, X.

Publications and source records attributed to Hu, X..

At least 181 records · Page 10Linked to original sources

bioRxiv2023

INTEGRATED GLOBAL CHICKEN REFERENCE PANEL FROM 13,187 CHICKEN GENOMES

Chickens are a crucial source of protein for humans and a popular model animal for bird research. Despite the emergence of imputation as a reliable genotyping strategy for large populations, the lack of a high-quality chicken reference panel has hindered progress in chicken genome research. To address this issue, here we introduce the first phase of the 100 K Global Chicken Reference Panel Project (100 K GCRPP). The project includes 13,187 samples and provides services for varied applications on its website (http://farmrefpanel.com/GCRP/). Currently, two panels are available: a Comprehensive Mix Panel (CMP) for domestication diversity research and a Commercial Breed Panel (CBP) for breeding broilers specifically. Evaluation of genotype imputation quality showed that CMP had the highest imputation accuracy compared to imputation using existing chicken panel in animal SNPAtlas, whereas CBP performed stably in the imputation of commercial populations. Additionally, we found that genome-wide association studies using GCRP-imputed data, whether on simulated or real phenotypes, exhibited greater statistical power. In conclusion, our study indicates that the GCRP effectively fills the gap in high-quality reference panels for chickens, providing an effective imputation platform for future genetic and breeding research.

bioinformatics↗

bioRxiv2023

Modulating social learning-induced evaluation updating during human sleep

People often change their evaluations upon learning about their peers evaluations, i.e., social learning. Given sleeps vital role in consolidating daytime experiences, sleep may facilitate social learning and thereby further changing peoples evaluations. Combining a social learning task and the sleep-based targeted memory reactivation technique, we asked whether social learning-induced evaluation changes can be modulated during sleep. After participants indicated their initial evaluation for snacks, they learned about their peers evaluation while hearing the snacks spoken names. During the post-learning non-rapid-eye-movement sleep, we re-played half of the snack names (i.e., cued snack) to reactivate the associated peers evaluations. Upon waking up, we found that the social learning-induced evaluation changes further enlarged for both cued and uncued snacks. Examining sleep electroencephalogram (EEG) activity revealed that cue-elicited delta-theta EEG power and the overnight N2 sleep spindle density predicted post-sleep evaluation changes for cued but not for uncued snacks. Our findings suggested that sleep-mediated memory reactivation processes could strengthen social learning-induced evaluation changes.

neuroscience↗

bioRxiv2023

Aversive memories can be weakened during human sleepvia the reactivation of positive interfering memories

Recollecting painful or traumatic experiences can be deeply troubling. Sleep may offer an opportunity to reduce such suffering. We developed a procedure to weaken older aversive memories by reactivating newer positive memories during sleep. Participants viewed 48 nonsense words each paired with a unique aversive image, followed by an overnight sleep. In the next evening, participants learned associations between half of the words and additional positive images, creating interference. During the following non-rapid-eye-movement sleep, auditory memory cues were unobtrusively delivered. Upon waking, presenting cues associated with both aversive and positive images during sleep, as opposed to not presenting cues, weakened aversive memory recall while increasing positive memory intrusions. Substantiating these memory benefits, computational modeling revealed that cueing facilitated evidence accumulation toward positive affect judgments. Moreover, cue-elicited theta brain rhythms during sleep predominantly predicted the recall of positive memories. A noninvasive sleep intervention can thus modify aversive recollection and affective responses. Significance StatementNot all memories are welcome: recollection and involuntary intrusions of aversive memories can be debilitating. Prior research shows that reactivating positive memories benefits psychological health, and memory reactivation can be externally triggered during human sleep. Here, we introduced a novel sleep-based memory updating procedure to weaken older aversive memories by reactivating newer positive memories. We found that such reactivation not only weakened the recall of aversive memories, but also increased involuntary intrusion of positive memories. Moreover, reactivation enhanced positive affect judgments. Our findings open new avenues for weakening aversive or traumatic memories during human sleep.

neuroscience↗

bioRxiv2023

Exclusion of PD-1 from the immune synapse: a novel strategy to modulate T cell function

Targeting immune checkpoint receptors on T cells is a common cancer treatment strategy. Frequently, this is accomplished through antibodies targeting the ligand of inhibitory co-receptors. Blocking the immune checkpoint PD-1 binding to its ligands PD-L1 and PD-L2 prevents downstream signaling and enhances anti-tumor T cell responses. This approach improved cancer patients outcome. However, only one-third of the patients respond to these treatments. To better understand the mechanism of anti-PD-1 antibodies, we explored the location of PD-1 within the immune synapse. Surprisingly, we discovered that anti-PD-1 antibodies, besides blocking the interaction between PD-1 and its ligands, also removed PD-1 from the synapse. We demonstrated a correlation between removing PD-1 from the synapse by anti-PD-1 antibodies and the extent of T cell activation. Interestingly, a short version of the anti-PD-1 antibody, F(ab)2, failed to remove PD-1 from the synapse and activate T cells. Using syngeneic tumor model, we showed a superior anti-tumor effect to anti-PD-1 antibody over the shorter version of the antibody. Our data indicates that anti-PD-1 antibodies activate T cells by removing PD-1 away from the synapse and changing the location of PD-1 or other immune receptors within immune synapse could serve as an alternative, efficient approach to treat cancer.

immunology↗

bioRxiv2023

Macrophage Depletion Protects Against Cisplatin-Induced Ototoxicity and Nephrotoxicity

Cisplatin is a widely used and highly effective anti-cancer drug with significant side effects including ototoxicity and nephrotoxicity. Macrophages, the major resident immune cells in the cochlea and kidney, are important drivers of both inflammatory and tissue repair responses. To investigate the roles of macrophages in cisplatin-induced ototoxicity and nephrotoxicity, we used PLX3397, an FDA-approved inhibitor of the colony-stimulating factor 1 receptor (CSF1R), to eliminate tissue-resident macrophages during the course of cisplatin administration. Mice treated with cisplatin alone (cisplatin/vehicle) had significant hearing loss (ototoxicity) as well as kidney injury (nephrotoxicity). Macrophage ablation using PLX3397 resulted in significantly reduced hearing loss measured by auditory brainstem responses (ABR) and distortion-product otoacoustic emissions (DPOAE). Sensory hair cells in the cochlea were protected against cisplatin-induced death in mice treated with PLX3397. Macrophage ablation also protected against cisplatin-induced nephrotoxicity, as evidenced by markedly reduced tubular injury and fibrosis as well as reduced plasma blood urea nitrogen (BUN) and neutrophil gelatinase-associated lipocalin (NGAL) levels. Mechanistically, our data suggest that the protective effect of macrophage ablation against cisplatin-induced ototoxicity and nephrotoxicity is mediated by reduced platinum accumulation in both the inner ear and the kidney. Together our data indicate that ablation of tissue-resident macrophages represents a novel strategy for mitigating cisplatin-induced ototoxicity and nephrotoxicity. Brief summaryMacrophage ablation using PLX3397 was protective against cisplatin-induced ototoxicity and nephrotoxicity by limiting platinum accumulation in the inner ear and kidney.

immunology↗

bioRxiv2023

Reprogramming of 3D chromatin domains by antagonizing the β-catenin/CBP interaction attenuates insulin signaling in pancreatic cancer

The therapeutic potential of targeting the {beta}-catenin/CBP interaction has been demonstrated in a variety of preclinical tumor models with a small molecule inhibitor, ICG-001, characterized as a {beta}-catenin/CBP antagonist. Despite the high binding specificity of ICG-001 for the N-terminus of CBP, this {beta}-catenin/CBP antagonist exhibits pleiotropic effects. Our recent studies found global changes in three-dimensional (3D) chromatin architecture in response to disruption of the {beta}-catenin/CBP interaction in pancreatic cancer cells. However, an understanding of the functional crosstalk between antagonizing the {beta}-catenin/CBP interaction effect changes in 3D chromatin architecture and thereby gene expression and downstream effects remains to be elucidated. Here we perform Hi-C analyses on canonical and patient-derived pancreatic cancer cells before and after the treatment with ICG-001. In addition to global alteration of 3D chromatin domains, we unexpectedly identify insulin signaling genes enriched in the altered chromatin domains. We further demonstrate the chromatin loops associated with insulin signaling genes are significantly weakened after ICG-001 treatment. We finally elicit the deletion of a looping of IRS1, a key insulin signaling gene, significantly impede pancreatic cancer cell growth, indicating that looping-mediated insulin signaling might act as an oncogenic pathway to promote pancreatic cancer progression. Our work shows that targeting aberrant insulin chromatin looping in pancreatic cancer might provide a therapeutic benefit.

cancer biology↗

bioRxiv2023

cSTAR analysis identifies endothelial cell cycle as a key regulator of flow-dependent artery remodeling

Fluid shear stress (FSS) from blood flow is sensed by vascular endothelial cells (ECs) to determine vessel stability, remodeling and susceptibility to atherosclerosis and other inflammatory diseases but the regulatory networks that govern these behaviors are only partially understood. We used cSTAR, a powerful new computational method, to define EC transcriptomic states under low shear stress (LSS) that triggers vessel inward remodeling, physiological shear stress (PSS) that stabilizes vessels, high shear stress (HSS) that triggers outward remodeling, and oscillatory shear stress (OSS) that confers disease susceptibility, all in comparison to cells under static conditions (STAT). We combined these results with the LINCS database where EC transcriptomic responses to drug treatments to define a preliminary regulatory network in which the cyclin-dependent kinases CDK1/2 play a central role in promoting vessel stability. Experimental analysis showed that PSS induced a strong late G1 cell cycle arrest in which CDK2 was activated. EC deletion of CDK2 in mice resulted in inward artery remodeling and both pulmonary and systemic hypertension. These results validate use of cSTAR to determine EC state and in vivo vessel behavior, reveal unexpected features of EC phenotype under different FSS conditions, and identify CDK2 as a key element within the EC regulatory network that governs artery remodeling.

cell biology↗

bioRxiv2023

Three Conserved Immune Dysfunction and Exclusion Subtypes in Bladder and Pan-cancers: Prognostic and Immunotherapeutic Significance

Molecular subtyping is expected to enable bladder cancer (BC) precise treatment. However, its clinical application remains defective and controversial. Given the significance of tumor immune dysfunction and exclusion (TIDE) in tumor immune escape and immunotherapy, we aimed to develop a novel TIDE-based subtyping method to facilitate personalized management. Transcriptome data of BC was used to evaluate the heterogeneity and the status of TIDE patterns. We identified 69 TIDE biomarker genes and classified BC samples into three subtypes. Subtype I showed the lowest TIDE status and malignancy with the best prognosis and highest sensitivity to immune checkpoint blockade (ICB) treatment, which was enriched of metabolic related signaling pathways. Subtype III represented the highest TIDE status and malignancy with the poorest prognosis and resistance to ICB treatment, resulting from its inhibitory immune microenvironment and T cell terminal exhaustion. Subtype II was in a transitional state with intermediate TIDE level, malignancy, and prognosis. We further confirmed the existence and characteristics of our novel TIDE subtypes using real-world BC samples. This subtyping method was proved to be more efficient than known methods in identifying non-responders to immunotherapy. We also found that combining our TIDE subtypes with known biomarkers can improve the sensitivity and specificity in predicting ICB response. Moreover, besides guiding ICB treatment, this classification approach can assist in selecting the frontline or recommended drugs. Finally, the TIDE subtypes are conserved across pan-tumors. In conclusion, our novel TIDE-based strategy is a powerful clinical tool for BC and pan-cancer patients, and potentially guiding personalized immunotherapy.

bioinformatics↗

bioRxiv2023

New tree shrew Parkinson's model: a cost-effective alternative to monkey models

The surge in demand for experimental monkeys has led to a rapid increase in their associated costs. Consequently, there is a growing need for the development of a cost-effective model for Parkinsons disease (PD) that exhibits all core clinical and pathological phenotypes of PD. Evolutionarily, tree shrews (Tupaia belangeri) are much closer to primates in comparison to rodents and share more similar PD-related brain structures and movement ability with monkeys. As such, tree shrews represent an ideal small animal species for modeling PD. To develop a tree shrew PD model, we used the 1-Methyl-4-phenylpyridinium (MPP+) metabolite, derived from the well-established PD modeling drug 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), to induce lesions in the dopaminergic neurons of the unilateral substantia nigra. After determining the optimal modeling dosage, the tree shrews consistently exhibited and maintained all classic clinical manifestations of PD for a 5-month period. The symptoms closely resembled the ones observed in PD monkeys and included bradykinesia, rest tremor, postural instability, and apomorphine-induced rotations, a classic phenotype of unilateral PD models. Immunostaining showed a significant loss of dopaminergic neurons (approximately 95%) in the substantia nigra on the lesioned side of the brain, a crucial pathological marker of PD. Further cytomorphological analysis revealed that the size of nigral dopaminergic neurons in tree shrews exceeded that of rodents and more closely approximated that of macaques. Based on the principle that structure determines function, the morphological similarity between tree shrews and monkeys may be an important structural basis for the manifestation of the highly similar phenotypes between monkey and tree shrew PD models. Collectively, this study successfully developed a PD model in a small animal species that faithfully recapitulated the classical clinical symptoms and key pathological indicators of PD monkeys. In addition to the well-recognized monkey models, the tree shrew model provides a novel avenue for the evaluation of PD treatments and underlying mechanisms.

neuroscience↗

bioRxiv2023

Overexpression of ZmSTOP1-A Enhances Aluminum Tolerance in Arabidopsis by Stimulating Organic Acid Secretion and Reactive Oxygen Species Scavenging

Aluminum (Al) toxicity and low pH are major factors limiting plant growth in acidic soils. Sensitive to Proton Rhizotoxicity 1 (STOP1) transcription factor respond to these stresses by regulating the expression of multiple Al- or low pH-responsive genes. ZmSTOP1-A, a STOP1-like protein from maize (Zea mays), was localized to the nucleus and had transactivation activity. ZmSTOP1-A was expressed moderately in both roots and shoots of maize seedlings, but was not induced by Al stress or low pH. Overexpression of ZmSTOP1-A in Arabidopsis Atstop1 mutant partially restored Al tolerance and completely low pH tolerance with respect to root growth. Regarding Al tolerance, ZmSTOP1-A/Atstop1 plants showed clear upregulation of organic acid transporter genes, and leading to increased organic acid secretion and reduced Al accumulation in roots. Besides, the antioxidant enzyme activity in roots and shoots of ZmSTOP1-A/Atstop1 plants was significantly enhanced, ultimately alleviating Al toxicity via scavenging reactive oxygen species. Similarly, ZmSTOP1-A could directly activate ZmMATE1 expression in maize, positively correlated with the number of Al-responsive GGNVS cis-element in the ZmMATE1 promoter. Our results revealed that ZmSTOP1-A antagonizes Al toxicity by enhancing organic acid secretion and reactive oxygen species scavenging in Arabidopsis, demonstrating that it is an important transcription factor conferring Al tolerance. Our findings help to comprehensively elucidate the role of STOP1-like transcript factor in enabling plants to detoxifying Al.

molecular biology↗

bioRxiv2023

Reduced brain glutathione levels during normal aging are associated with visuospatial memory

During aging, the brain is subject to greater oxidative stress (OS), which is thought to play a critical role in cognitive impairment. Glutathione (GSH), as a major antioxidant in the brain, can be used to combatting OS. However, how brain GSH levels vary with age and their associations with cognitive function remain unclear. In this study, we combined point-resolved spectroscopy and edited spectroscopy sequences to investigate GSH levels in the anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), and occipital cortex (OC) of 276 healthy participants (166 females, age range 20-70 years) and examined their relationships with age and cognitive function. The results revealed decreased GSH levels with age in the PCC among all participants. Notably, the timecourse of GSH level changes in the PCC and ACC differed between males and females. Additionally, positive correlations were observed between GSH levels in the PCC and OC and visuospatial memory. Taken together, these findings enhance our understanding of the brain GSH timecourse during normal aging and associations with sex and memory, which is an essential first step for understanding the neurochemical underpinnings of OS-related diseases.

neuroscience↗

bioRxiv2023

MELISSA: Semi-Supervised Embedding for Protein Function Prediction Across Multiple Networks

MotivationSeveral popular methods exist to predict function from multiple protein-protein association networks. For example, both the Mashup algorithm, introduced by Cho, Peng and Berger, and deepNF, introduced by Gligorijevi[c], Barotand, and Bonneau, analyze the diffusion in each network first, to characterize the topological context of each node. In Mashup, the high-dimensional topological patterns in individual networks are canonically represented using low-dimensional vectors, one per gene or protein, to yield the multi-network embedding. In deepNF, a multimodal autoencoder is trained to extract common network features across networks that yield a low-dimensional embedding. Neither embedding takes into account known functional labels; rather, these are then used by the machine learning methods applied after embedding. ResultsWe introduce MELISSA (MultiNetwork Embedding with Label Integrated Semi-Supervised Augmentation) which incorporates functional labels in the embedding stage. The function labels induce sets of "must link" and "cannot link" constraints which guide a further semi-supervised dimension reduction to yield an embedding that captures both the network topology and the information contained in the annotations. We find that the MELISSA embedding improves on both the Mashup and deepNF embeddings in creating more functionally enriched neighborhoods for predicting GO labels for multiplex association networks in both yeast and humans. AvailabilityMELISSA is available at https://github.com/XiaozheHu/melissa

bioinformatics↗

bioRxiv2023

Iterative In Silico Screening for Optimizing Stable Conformation of Anti-SARS-CoV-2 Nanobodies

Nanobodies (Nbs or VHHs) are single-domain antibodies (sdAbs) derived from camelid heavy-chain antibodies. The variable region of these nanobodies has special and unique characteristics, such as small size, good tissue penetration, and cost-effective production, making nanobodies a good candidate for the diagnosis and treatment of viruses. Identifying effective nanobodies against the COVID-19 would help us defeat this dangerous virus or other unknown variants in future. Herein, we introduce an in silico screening strategy for optimizing stable conformation of anti-SARS-CoV-2 nanobodies. Firstly, various complexes containing nanobodies were downloaded from the RCSB database, which were identified from immunized llamas. The primary docking between nanobodies and the SARS-CoV-2 spike protein receptor-binding domain was performed through ClusPro program, with the manually screening that leaving the reasonable conformation to the next step. Then, the binding distances of atoms between the antigen-antibody interfaces were measured through the NeighborSearch algorithm. Finally, filtered nanobodies were acquired according to HADDOCK scores through HADDOCK docking the COVID spike protein with nanobodies under restrictions of calculated molecular distance between active residues and antigenic epitopes less than 4.5 [A]. In this way, those nanobodies which with more reasonable conformation and with stronger neutralizing efficacy were acquired. To validate the efficacy ranking of the nanobodies we obtained, we calculated the binding affinities ({Delta}G) and dissociation constants (Kd) of all screened nanobodies using the PRODIGY web tool, and predicted the stability changes induced by all possible point mutations in nanobodies using the MAESTROWeb server. Furthermore, we examined the performance of the relationship between nanobodies ranking and their number of mutation-sensitive sites (Spearman correlation > 0.68), the results revealed a robust correlation, indicating that the superior nanobodies identified through our screening process exhibited fewer mutation hotspots and higher stability. This correlation analysis demonstrates the validity of our screening criteria, underscoring the suitability of these nanobodies for future development and practical implementation. In conclusion, this three-step screening strategy iteratively in silico greatly improved the accuracy of screening desired nanobodies compared to using only ClusPro docking or default HADDOCK docking settings. It provides new ideas for the screening of novel antibodies and computer-aided screening methods.

bioinformatics↗

bioRxiv2023

The influence of HLA genetic variation on plasma protein expression

Polymorphism in the human leukocyte antigen class I (HLA-I) and class II (HLA-II) genes is strongly implicated in susceptibility to immune-mediated diseases. However, the molecular effects of HLA genetic variation, including and beyond antigen presentation, remain unclear. Here we examined the effect of HLA genetic variation on the expression of 2940 plasma proteins using imputed HLA variants in 45,330 Europeans in the UK Biobank. We detected 504 proteins (17.1% of all proteins tested) affected by HLA genetic variation (HLA-pQTL), including widespread trans regulation of protein expression by autoimmune disease risk alleles. HLA-pQTL were enriched in gene families related to antigen presentation (e.g. B2M), T cell fate (CD8A; CD4), chemokines (CCL19; CCL21), and NK and macrophage receptors (KIR; LILRA/B), suggesting that HLA polymorphism affects both adaptive and innate immunity. HLA-pQTL also affected expression of diverse proteins with unclear roles in the immune response (e.g. SFTPD, LRPAP1, ENPP6, NPTX1), as well as drug targets for immune-mediated diseases, suggesting complex regulatory roles of the HLA loci. Among trans HLA-pQTL, HLA variants explained 0.1-42.9% of the protein expression variance. Fine-mapping revealed that most HLA-pQTL implicated amino acid positions within the peptide binding groove, suggesting that trans regulation of plasma protein expression by the HLA loci is primarily a consequence of antigen presentation. We also show that HLA-I and II uniquely affect different proteins and biological mechanisms. Altogether, our data reveal the effects of HLA genetic variation on protein expression and aid the interpretation of associations between HLA alleles and immune-mediated diseases.

genetics↗

bioRxiv2023

T2T-YAO: a Telomere-to-telomere Assembled Diploid Reference Genome for Han Chinese

Since its initial release in 2001, the human reference genome has been continuously improved in both continuity and accuracy, and the recently-released telomere-to-telomere version--T2T-CHM13--reaches its top quality after 20 years of effort. However, T2T-CHM13 does not represent an authentic diploid human genome, but rather one derived from a simplified, nearly homozygous genome of a hydatidiform mole cell line. To address this limitation and provide an alternative pertinent to the Chinese population, the largest ethnic group in the world, we have assembled a complete diploid human genome of a male Han Chinese, T2T-YAO, which includes telomere-to-telomere assemblies for all the 22+X+M and 22+Y chromosomes in his two haploids inherited separately from his parents. Both haplotypes contain no artificial sequences or model nucleotides and possess a high quality comparable to CHM13, with fewer than one error per [~]14 Mb. Derived from the individual who lives in the aboriginal region of Han Chinese, T2T-YAO shows clear ancestry and potential genetic continuity from the ancient ancestors of the Han population. Each haplotype of T2T-YAO possesses [~]340 Mb exclusive sequences and [~]3100 unique genes as compared to CHM13, and their genome sequences show greater genetic distance to CHM13 than to each other in terms of nucleotide polymorphism and structural variations. The construction of T2T-YAO would serve as a high-quality diploid reference that enables precise delineation of genomic variations in a haplotype-sensitive manner, which could advance our understandings in human evolution, hereditability of diseases and phenotypes, especially within the context of the unique variations of the Chinese population.

genetics↗

bioRxiv2023

Non-cell autonomous cardiomyocyte regulation complicates gene supplementation therapy for LMNA cardiomyopathy

AimsRecombinant adeno-associated viruses (rAAVs) are federally approved gene delivery vectors for in vivo gene supplementation therapy. Loss-of-function truncating variants of LMNA, the coding gene for Lamin-A/C, are one of the primary causes of inherited dilate cardiomyopathy (DCM). Here we aim to study whether AAV-based LMNA supplementation could treat LMNA deficiency-triggered cardiac defects. Methods and ResultsWe compared whole-body, cardiomyocyte-specific and genetic-mosaic mouse models that carry Lmna truncating variants at the same genetic loci and uncovered primarily a non-cell autonomous impact of Lmna on cardiomyocyte maturation. Whole-body lamin-A supplementation by rAAVs moderately rescued the cardiac defects in Lmna germline mutants. By contrast, cardiomyocyte-specific lamin-A addback failed to restore the cardiomyocyte growth defects. A Cre-loxP-based AAV vector that expresses lamin-A throughout the body but excluding the heart was able to restore cardiomyocyte growth in Lmna germline mutants. ConclusionsLmna regulates cardiomyocyte growth non-cell autonomously. Non-myocytes are the key cell targets for a successful gene therapy for LMNA-associated cardiac defects. Translational perspectiveLMNA truncating mutations are among the major causes of inherited DCM. AAV gene supplementation therapy is emerging as a promising strategy to treat genetic cardiomyopathy, but whether this strategy is suitable for LMNA cardiomyopathy remained unclear. Our study counterintuitively showed that the cardiomyocytes are not necessarily the correct therapeutic cell targets for AAV-based treatment of LMNA cardiomyopathy. By contrast, careful elucidation of cell-autonomous versus non-cell-autonomous gene functions is essential for the proper design of a gene supplementation therapy for cardiomyopathy. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=189 SRC="FIGDIR/small/549413v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@37cfdaorg.highwire.dtl.DTLVardef@2f2cd1org.highwire.dtl.DTLVardef@1278d08org.highwire.dtl.DTLVardef@19c4869_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2023

T4SEpp: a pipeline integrated with protein language models effectively predicting bacterial type IV secreted effectors

Many pathogenic bacteria use type IV secretion systems(T4SSs) to deliver effectors (T4SEs) into the cytoplasm of eukaryotic cells, causeing diseases. The identification of effectors is a crucial step in understanding the mechanisms of bacterial pathogenicity, but this remains a major challenge. In this study, we used the full-length embedding features generated by six pre-trained protein language models to train classifiers predicting T4SEs, and compared their performance. An integrated model T4SEpp was assembled by a module searching full-length, signal sequence and effector domain homologs of known T4SEs, a machine learning module based on the hand-crafted features extracted from the signal sequences, and the third module containing three best-performing protein language pre-trained models. T4SEpp outperformed the other state-of-the-art (SOTA) software tools, achieving [~]0.95 sensitivity at a high specificity of [~]0.99, based on the assessment of an independent testing dataset. Additionally, we performed a comprehensive search among 8,761 bacterial species, leading to the discovery of 227 species belonging to 3 phyla and 117 genera that possess T4SSs. Furthermore, leveraging the power of T4SEpp, we successfully identified a grand total of 12,622 plausible T4SEs. Overall, T4SEpp provides a better solution to assist in the identification of bacterial T4SEs, and facilitates studies of bacterial pathogenicity. T4SEpp is freely accessible at https://bis.zju.edu.cn/T4SEpp.

bioinformatics↗

bioRxiv2023

MicroRNA-122-mediated liver detargeting enhances the tissue specificity of cardiac genome editing

BackgroundThe cardiac troponin T (Tnnt2) promoter is broadly utilized for cardiac specific gene expression, particularly via adeno-associated virus (AAV)-based gene transfer. However, these vectors drive lower-level ectopic gene expression in other tissues, most notably in the liver. Whether the AAV-Tnnt2 vectors remain tissue-specific in applications sensitive to low or transient gene expression, such as gene editing, remains unclear. MethodsThe tissue specificity of AAV9-Tnnt2 vectors was evaluated in mice using Cre-LoxP-based fluorescence reporters and CRISPR/Cas9-mediated somatic mutagenesis. CRISPR/Cas9-triggered AAV integration into host genome was further assessed by quantitative PCR. ResultsIn mice treated with AAV-Tnnt2-GFP, GFP signal was specifically observed in the heart by confocal imaging. However, when AAV-Tnnt2-Cre was administered to mice carrying LoxP-STOP-LoxP fluorescence reporters, the reporter signals were observed in up to 50% hepatic cells. Similarly, the AAV-Tnnt2-SaCas9 vector extensively edited the hepatic genome as measured by targeted amplicon-sequencing. Cas9-triggered AAV integration into the host genome was also validated in the liver. Inclusion of target sequences for microRNA-122, a highly expressed, liver-specific microRNA, in the AAV transgenes 3 untranslated region (3 UTR) markedly reduced ectopic transgene expression, genome editing and AAV integration in the liver. ConclusionsThe heavily used AAV-Tnnt2 system exhibits liver leakiness that severely impairs the cardiac specificity of AAV-based genetic manipulation. This problem can be mitigated via miR122-mediated liver detargeting.

physiology↗