Biology subjects

Zhang, K.

Publications and source records attributed to Zhang, K..

At least 163 records · Page 9Linked to original sources

bioRxiv2024

PlateletBase: A Comprehensive Knowledgebase for Platelet Research and Disease Insights

Platelets are vital in many pathophysiological processes, yet there is a lack of a comprehensive resource dedicated specifically to platelet research. To fill this gap, we have developed PlateletBase, a knowledge base aimed at enhancing the understanding and study of platelets and related diseases. Our team retrieved information from various public databases, specifically extracting and analyzing RNA-seq data from 3,711 samples across 41 different conditions available on NCBI. PlateletBase offers six analytical and visualization tools, enabling users to perform gene similarity analysis, pair correlation, multi-correlation, expression ranking, clinical information association, and gene annotation for platelets. The current version of PlateletBase includes 10,278 genomic entries, 31,758 transcriptomic entries, 4,869 proteomic entries, 2,614 omics knowledge entries, 1,833 drugs, 97 platelet resources, 438 diseases/traits, and six analysis modules. Each entry has been carefully curated and supported by experimental evidence. Additionally, PlateletBase features a user-friendly interface designed for efficient querying, manipulation, browsing, visualization, and analysis of detailed platelet protein and gene information. Case study results, such as those from gray platelet syndrome and angina pectoris, demonstrate that this tool can aid in identifying diagnostic biomarkers and exploring disease mechanisms, significantly advancing research in platelet functionality and its applications. PlateletBase is accessible at http://plateletbase.clinlabomics.org.cn/.

bioinformatics↗

bioRxiv2024

p300/CBP-catalyzed acetylation safeguards minor zygotic genome activation via activating DUX

Zygotic genome activation (ZGA), the first transcriptional event at the onset of life, is crucial for early embryonic development. However, the mechanisms that initiate and regulate ZGA in mammals remain poorly understood. In this study, we demonstrate that p300/CBP-catalyzed acetylation plays a vital role in regulating ZGA. Inhibition of p300/CBP acetyltransferase activity results in impaired minor ZGA and a subsequent 2-cell arrest. By profiling the dynamic landscape of p300 during the ZGA stage, we elucidate the distinct patterns of p300 establishment in promoter and enhancer regions. Moreover, p300 recruits RNA polymerase (Pol II) to pre-configure in the promoter regions of ZGA genes, and orchestrates the gradual establishment of enhancer activity during the early 2-cell stage to activate ZGA. Furthermore, p300 enhances minor ZGA by promoting the expression of DUX. Restoring DUX levels, which are diminished due to p300/CBP inhibition, rescues ZGA and embryonic development by re-establishing Pol II enrichment on minor ZGA genes. Overall, our findings elucidate the mechanism by which p300/CBP regulates ZGA through acetylation and activation of the key transcription factor DUX. HighlightsO_LIp300/CBP plays a stage-specific role during preimplantation development phase. C_LIO_LIp300 displays distinctive dynamic changes in promoter and enhancer regions during ZGA stage. C_LIO_LIp300/CBP-catalyzed acetylation facilitates the pre-configuration and elongation of Pol II at ZGA gene regions. C_LIO_LIDUX recruits p300 and Pol II to activate minor ZGA genes independently of p300s catalytic activity. C_LI

developmental biology↗

bioRxiv2024

TLL1 knockdown attenuates prostate cancer progression by enhancing antitumor immunity

Due to the inevitable progression to castration-resistant prostate cancer (CRPC) following treatment with androgen deprivation therapy (ADT), it is essential to develop novel treatment approaches for managing CRPC. Here we showed that metalloproteinase TLL1 was positively associated with prostate cancer aggressiveness. Mechanistically, TLL1 promoted prostate cancer cells migration and metastasis through cleaving latent TGF-{beta}1 to activate TGF-{beta} signaling pathway. Moreover, LINC01179 interacted with Miz1 to attenuate TLL1 expression and LINC01179 impaired prostate cancer cell proliferation and migration ability by suppressing TLL1 expression to deactivate TGF-{beta} signaling activity. Meanwhile, we observed that TLL1 increased the expression of PD-L1 by activating TGF-{beta} signaling pathway and TLL1 depletion enhanced the antitumor efficacy by anti-PD-1 antibody via augmenting the infiltration proportions of CD8+ T cells in tumors. In addition, T cell-specific overexpression of TLL1 disrupted T cell development in the thymus. TLL1 overexpression in T cells accelerated RM-1 prostate tumor growth in mice by decreasing the infiltration of CD8+ T cells into tumors. Collectively, our results revealed that TLL1 may be a potential therapeutic target to alter prostate cancer progression.

cancer biology↗

bioRxiv2024

Genomic Analysis of Progenitors in Viral Infection Implicates Glucocorticoids as Suppressors of Plasmacytoid Dendritic Cell Generation

Plasmacytoid Dendritic cells (pDCs) are the most potent producers of interferons, which are critical antiviral cytokines. pDC development is, however, compromised following a viral infection, and this phenomenon, as well as its relationship to conventional (c)DC development is still incompletely understood. By using lymphocytic choriomeningitis virus (LCMV) infection in mice as a model system, we observed that DC progenitors skewed away from pDC and towards cDC development during in vivo viral infection. Subsequent characterization of the transcriptional and epigenetic landscape of fms-like tyrosine kinase 3+ (Flt3+) DC progenitors and follow-up studies revealed increased apoptosis and reduced proliferation in different individual DC-progenitors as well as a profound IFN-I-dependent ablation of pre-pDCs, but not pre-DC precursor, after both acute and chronic LCMV infections. In addition, integrated genomic analysis identified altered activity of 34 transcription factors in Flt3+ DC progenitors from infected mice, including two regulators of Glucocorticoid (GC) responses. Subsequent studies demonstrated that addition of GCs to DC progenitors led to downregulated pDC-primed-genes while upregulating cDC-primed-genes, and that endogenous GCs selectively decreased pDC, but not cDC, numbers upon in-vivo LCMV infection. These findings demonstrate a significant ablation of pre-pDCs in infected mice and identify GCs as suppressors of pDC generation from early progenitors. This provides an explanation for the impaired pDC development following viral infection and links pDC generation to the hypothalamic-pituitary-adrenal axis. Significance StatementPlasmacytoid dendritic cells (pDCs) play critical roles in antiviral responses. However, adaptations of DC progenitors lead to compromised pDC generation after viral infection. Here, we characterized the transcriptional and epigenetic landscapes of DC progenitors after infection. We observed widespread changes in gene expression and chromatin accessibility, reflecting shifts in proliferation, apoptosis, and differentiation potential into various DC subsets. Notably, we identified alterations in the predicted activity of 34 transcription factors, including two regulators of glucocorticoid responses. Our data demonstrate that glucocorticoids inhibit pDC generation by reprogramming DC progenitors. These findings establish a molecular framework for understanding how DC progenitors adapt to infection and highlight the role of glucocorticoid signaling in this process.

immunology↗

bioRxiv2024

Sirtuin2 blockade inhibits replication of Human Immunodeficiency Virus-1 and 1 Mycobacterium tuberculosis in macrophages and humanized mice

Coinfections with Mycobacterium tuberculosis (Mtb) and HIV-1 present a critical health challenge and require treatment for survival. We found that human M1 macrophages inhibit Mtb growth, while M2 macrophages, characterized by elevated Sirt2 expression, permit Mtb growth. Further, we found that HIV-1 augmented Sirt2 gene expression in M[FE]s. Therefore, we explored the therapeutic potential of sirtuin-modulating drugs in M[FE]s. Sirtinol, a Sirt2 inhibitor, significantly reduced HIV-1 growth in M0, M1, and M2-M[FE]s by >1 log10 over 7 days. Conversely, individual doses of resveratrol and SRT1460, which activate Sirt1, did not affect HIV-1. However, their combination showed a strong synergistic inhibition of HIV-1. The combination of sirtinol with resveratrol was neither synergistic nor antagonistic. Sirtinol upregulated iNOS and ATG5 mRNA in HIV-1 infected M[FE]s in a phenotype-dependent manner. In a humanized mouse model (Hu-NSG-SGM3) co-infected with Mtb H37Rv and the HIV-1 BAL strain, treatment with sirtinol alone, or in combination with combination antiretroviral therapy (cART), showed promising results; Sirtinol alone reduced Mtb growth, while its combination with cART effectively inhibited HIV-1 replication in the organs. We propose that Sirt2 blockade and Sirt1-activation represent a novel dual therapeutic strategy for treating HIV-1 and Mtb coinfections.

immunology↗

bioRxiv2024

Thermal biology of aphids and implications for agriculture and food security

Climate change poses significant challenges to agriculture and food security, particularly through its effects on insect vector populations and the pathogens they transmit. Aphids are one of the biggest group of ectotherms that transmit viruses to plants; more than 200 species have been identified as pathogen vectors. These aphids are responsible for transmitting over 300 viruses. The life-history traits of aphids such as fecundity and survival respond strongly and non-linearly to temperature and therefore to global warming. In this study, we elaborate the thermal responses for the main life-history traits (i.e, development and mortality rate) for aphid species for which data were available or generated. Also, thermal responses for virus transmission rates were elaborated to describe plant host to vector and vector to plant host dynamics. With these data, we elaborated thermal suitability models which were used to map current and projected scenarios for the transmission of viruses by aphids. Data was only available/generated for 19 aphid species, many of which only have data either at the lower or upper thermal limits. For virus transmission rates, from host plant to vector and from vector to plant data was only available/generated for potato virus Y (PVY), potato virus A (PVA), and potato leaf roll virus (PLRV) transmitted by the aphid Myzus persicae. Projections show that virus transmission by aphids will shift to northern latitudes. Understanding the thermal biology of aphids is crucial for developing effective measures to safeguard agriculture, especially staple crops, and food security in the context of climate change.

plant biology↗

bioRxiv2024

Dynamic Models of Neural Population Dynamics

The recent developments in artificial intelligence (AI) increase the hope that AI can provide a powerful tool to facilitate scientific discovery and to generate and validate new ideas for scientific research autonomously. Large Language Models (LLMs), such as ChatGPT4 have demonstrated remarkable capabilities in understanding and generating human-like text. Their potential extends beyond simple language tasks, offering transformative possibilities in scientific research of all fields. By leveraging vast amounts of data and advanced computational power, LLMs can assist researchers in generating novel ideas, automating routine tasks, and fostering interdisciplinary collaborations. On September 12, 2024, OpenAI released their updated generative artificial intelligence system called ChatGPTo1. This new AI system, built upon chain-of-thought and reinforcement learning, has greatly enhanced logical reasoning abilities and can effectively solve various complex problems from elementary-level mathematical problems to modern scientific research issues in physics, chemistry, and biology. Unlike previous LLMs in which logical reasoning and data analysis abilities are developed through training on actual data, ChatGPTo1 logical reasoning ability and capacity to generate new scientific ideas are primarily acquired through chain-of-thought processes and reinforcement learning rather than pre-training. To examine this, we specifically tested ChatGPTo1 current reasoning and scientific discovery capabilities by developing theoretically complex and quantitatively challenging scientific equations in various fields of neuroscience, such as dynamical systems, nonlinear dynamical systems, dynamical systems on differential manifolds, neural field theory, nonlinear divergence theorems, nonlinear heat conduction equations and Laplace equations and their extensions on differential manifolds, nonlinear statistical analysis methods, deep learning, and other topics involving multiple fields. The current large language models may illustrate a certain degree of general intelligence, even if fundamentally it may be different from human intelligence. However, it does not mean the current LLMs can fully apply such ability in practical applications or that their reasoning potential can be fully tapped. It is essential to explore specific pathways and methods to cultivate their potential for scientific discovery. To accomplish this, we consider how to integrate them with common search engines (such as Google) capabilities and ChatGPT4o cross-modal abilities to better understand new disciplines and scientific discoveries. To this point, the major shortcoming of ChatGPTo1 is that it is not an end-to-end scientific discovery method and lacks the ability to achieve full automation. It also lacks methods for image analysis and full-scale data analysis, making it difficult to use simulation and data analysis to evaluate and test proposed new theories and methods.

neuroscience↗

bioRxiv2024

Synergy between cis-regulatory elements can render cohesin dispensable for distal enhancer function

Enhancers are critical genetic elements controlling transcription from promoters, but the mechanisms by which they convey regulatory information across large genomic distances remain elusive. Here, we engineered pluripotent stem cells in which cohesin loop extrusion can be inducibly disrupted without causing confounding cell cycle defects. While evident, transcriptional dysregulation was cell-type specific, and not all loci with distal enhancers depend equally on cohesin extrusion. Using comparative genome editing, we demonstrate that enhancer-promoter communication across as little as 20 kilobases can rely on cohesin. However, promoter-proximal regulatory elements can support long-range, cohesin-independent enhancer action - either upon disabling extrusion or across strong CTCF insulators. Finally, transcriptional dynamics and the emergence of new embryonic cell types in response to differentiation cues remained largely robust to disrupting cohesin extrusion. Beyond establishing novel experimental strategies to study cohesin functions in enhancer biology, our work provides mechanistic insight accounting for both cell type- and genomic context-specificity.

molecular biology↗

bioRxiv2024

D-lactate derived from intestinal bacteria drives lysine D-lactylation to modulate transcription in liver cells

Emerging evidence indicates that the accumulated D-lactate (D-la) from intestinal bacteria induces diverse effects in human intestinal injury diseases. However, its regulatory mechanism and functional consequence remain unclear. Here, we show that the secreted D-la induces lysine D-lactylation (K-Dla) to modulate transcription in host cells. We uncover K-Dla in HepG2 cells stimulated by D-la from E. coli secretions. Then, we confirm the occurrence of D-la-driven K-Dla by four orthogonal approaches. We further validate that the existence of K-Dla in organisms by detecting the mouse liver and human intestinal tissue. Besides, we demonstrate a SCOT1-catalyzed biosynthetic pathway of D-lactyl-CoA, serving as a key donor for K-Dla. Next, we identify the K-Dla landscape with 2895 sites and further suggest the regulation of histone K-Dla in transcription by MNase ChIP-seq and RNA-seq assays. Finally, we show the potential effect of K-Dla on inhibiting the hepatocellular carcinoma cell proliferation. In summary, we report that the secreted D-la can induce K-Dla to regulate transcription, providing a new insight into the function of D-la secreted by gut microbiota and the effect of protein chemical modifications induced by bacterial secretions.

molecular biology↗

bioRxiv2024

New Statistical Metric for Robust Target Detection in Cryo-EM Using 2DTM

2D template matching (2DTM) can be used to detect molecules and their assemblies in cellular cryo-EM images with high positional and orientational accuracy. While 2DTM successfully detects spherical targets such as large ribosomal subunits, challenges remain in detecting smaller and more aspherical targets in various environments. In this work, a novel 2DTM metric, referred to as the 2DTM p-value, is developed to extend the 2DTM framework to more complex applications. The 2DTM p-value combines information from two previously used 2DTM metrics, namely the 2DTM signal-to-noise ratio (SNR) and z-score, which are derived from the cross-correlation coefficient between the target and the template. The 2DTM p-value demonstrates robust detection accuracies under various imaging and sample conditions and outperforms the 2DTM SNR and z-score alone. Specifically, the 2DTM p-value improves the detection of aspherical targets such as a modified artificial tubulin patch particle (500 kDa) and a much smaller clathrin monomer (193 kDa) in simulated data. It also accurately recovers mature 60S ribosomes in yeast lamellae samples, even under conditions of increased Gaussian noise. The new metric will enable the detection of a wider variety of targets in both purified and cellular samples through 2DTM.

biophysics↗

bioRxiv2024

Making Aptamers More Antibody-like: Targeting AXL in Vivo Using a Bottlebrush Polymer-Conjugated Aptamer

The overexpression of receptor tyrosine kinase AXL is linked to acquired drug resistance in cancer treatments. Aptamers, acting as antibody surrogates, have been envisioned as potential inhibitors for AXL. However, aptamers face difficult pharmacological challenges including rapid degradation and clearance. Herein, we report a phosphodiester-backboned bottlebrush polymer as a carrier for conjugated aptamers. Termed pacDNA, the conjugate improves aptamer specificity in vivo, prolongs blood retention, and enhances overall aptamer bioactivity. Treatment with pacDNA in AXL-overexpressing cell lines significantly inhibits AXL phosphorylation, resulting in reduced cancer cell migration and invasion. In a non-small cell lung cancer xenograft model (NCI-H1299), pacDNA treatment leads to single-agent reduction in tumor growth. These results highlight the potential of bottlebrush polymers in the field of aptamer therapeutics.

cancer biology↗

bioRxiv2024

Bottlebrush polymers with sequence-controlled backbones for enhanced oligonucleotide delivery

The clinical translation of oligonucleotide-based thera-peutics continues to encounter challenges in delivery. In this study, we introduce a novel class of delivery vehicles for oligonucleotides, which are based on polyethylene glycol (PEG) bottlebrush polymers with sequence-defined backbones. Using solid-phase synthesis and bespoke phosphoramidites, the oligonucleotide and the polymer backbone can both be assembled on the solid support. The synthesis allows chemical modifiers such as carbon 18 (C18) units to be incorporated into the backbone in specific patterns to modulate the cell-materials interactions. Subsequently, PEG side chains were grafted onto the polymer segment of the resulting polymer-oligonucleotide conjugate, yielding bottlebrush polymers. We report an optimal pattern of the C18 modifier that leads to improved cellular uptake, plasma phar-macokinetics, biodistribution, and antisense activity in vivo. Our results provide valuable insights into the pacDNA structure-property relationship and suggest a possibility of tuning the polymer backbone to meet the specific delivery requirements of various diseases. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=166 SRC="FIGDIR/small/616318v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1a332e7org.highwire.dtl.DTLVardef@1630ab1org.highwire.dtl.DTLVardef@15306dforg.highwire.dtl.DTLVardef@1e83f0e_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2024

Maximizing memory capacity in heterogeneous networks

A central problem in neuroscience is identifying the features of neural networks that determine their memory capacity and assessing whether these features are optimized in the brain. In this study, we estimate the capacity of a general class of network models. Our derivation extends previous theoretical results, which assumed homogeneous connections and coding levels (i.e., activation rates of the neurons in memory patterns), to models with arbitrary architectures (varying constraints on the arrangement of connections between cells) and heterogeneous coding levels. Using our analytical results, we estimate the memory capacity of two types of brain-inspired networks: a general class of heterogeneous networks and a two-layer model simulating the CA3-Dentate Gyrus circuit in the hippocampus, known to be crucial for memory encoding. In the first case, we demonstrate that to maximize memory capacity, the number of inward connections and the coding levels of neurons must be correlated, presenting a normative prediction that is amenable to experimental testing. In the second case, we show that memory capacity is maximized when the connectivity and coding levels are consistent with the formation of memory "indices" in the Dentate Gyrus, which bind features in the CA3 layer. This suggests specific neural substrates for the hippocampal index theory of memory encoding and retrieval.

neuroscience↗

bioRxiv2024

Patterned wireless transcranial optogenetics generates artificial perception

Synthesizing perceivable artificial neural inputs independent of typical sensory channels remains a fundamental challenge in the development of next-generation brain-machine interfaces. Establishing a minimally invasive, wirelessly effective, and miniaturized platform with long-term stability is crucial for creating a clinically meaningful interface capable of mediating artificial perceptual feedback. In this study, we demonstrate a miniaturized fully implantable wireless transcranial optogenetic encoder designed to generate artificial perceptions through digitized optogenetic manipulation of large cortical ensembles. This platform enables the spatiotemporal orchestration of large-scale cortical activity for remote perception genesis via real-time wireless communication and control, with optimized device performance achieved by simulation-guided methods addressing light and heat propagation during operation. Cue discrimination during operant learning demonstrates the wireless genesis of artificial percepts sensed by mice, where spatial distance across large cortical networks and sequential order-based analyses of discrimination performance reveal principles that adhere to general perceptual rules. These conceptual and technical advancements expand our understanding of artificial neural syntax and its perception by the brain, guiding the evolution of next-generation brain-machine communication.

neuroscience↗

bioRxiv2024

Immune Cell Influence on Diffuse Large B-Cell Lymphoma: A Mendelian Randomization Analysis

ObjectiveTo elucidate the causal relationship between immune cells and diffuse large B-cell lymphoma (DLBCL), we conducted a Mendelian randomization analysis. MethodsMendelian randomization (MR) leverages genetic variants as instruments to infer causal effects from observational data. Here, we performed a two-sample MR analysis to assess the causal impact of 731 immune cell types on DLBCL. We employed various MR techniques, including the weighted median estimator (WME) and inverse variance weighting (IVW), and conducted sensitivity analyses to ensure result robustness. Additionally, reverse MR analysis was performed to explore the potential causal relationship between DLBCL and immune cells. ResultsWe identified seventeen immune features with causal links to DLBCL, categorized across various cellular groups: four in B cells, two in T cell maturation stages, six in Tregs, four in the TBNK group, and one in dendritic cells (DCs). Sensitivity analyses confirmed the absence of heterogeneity, horizontal pleiotropy, and bias in our findings. Reverse causal analysis revealed a causal association between DLBCL and one of the seventeen immune cell types identified. ConclusionsOur MR analysis of seventeen immune cell types uncovers the complex interactions between the immune system and DLBCL, providing crucial insights into the tumor microenvironment and potential avenues for targeted immunotherapy.

immunology↗

bioRxiv2024

Phosphatase-independent suppression of mucosal inflammation and disease progression by Salmonella SopB

Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) translocates effector molecules via its Salmonella pathogenicity island (SPI)1 encoded type 3 secretion system (T3SS) to induce internalization by intestinal epithelial cells and manipulate cellular responses. Among these effector molecules, the Salmonella outer protein B (SopB) was shown to possess phosphatidyl-inositol phosphatase activity and induce bacterial internalisation, promote cell survival, influence endosomal trafficking and alter host cell signalling. Using a neonatal S. Typhimurium infection model, we here show that SopB in vivo suppresses early epithelial chemokine expression, delays mucosal immune cell recruitment, reduces barrier impairment by enterocyte necroptosis, and prevents disease progression and premature death. Unexpectedly, this immunosuppressive effect was independent of the phosphatidyl-inositol phosphatase and phosphotransferase activity of SopB but required an intact N-terminal domain. Thus, SopB exerts a potent phosphatase-independent immunosuppressive effect to delay local tissue inflammation and disease progression likely to promote host transmission.

microbiology↗

bioRxiv2024

Gain-of-function study reveals the pleiotropic roles of serine protease HtrA in Borrelia burgdorferi

High-temperature requirement protease A (HtrA) is a family of serine proteases degrading misfolded and damaged proteins that are toxic to bacteria. The Lyme disease agent Borrelia burgdorferi encodes a single HtrA (BbHtrA). Previous studies have shown that BbHtrA is a key virulence determinant of B. burgdorferi as a deletion mutant of htrA ({Delta}htrA) fails to establish infection in mice. However, previous complementation could only restore protein expression but not infectivity in mice. In this report, we first identify the native promoter of BbHtrA which allows us to construct a fully complemented{Delta} htrA strain. Follow up promoter activity analysis reveals that BbHtrA is likely dually regulated by the house keeping sigma factor RpoD and the alternative sigma factor RpoS. The{Delta} htrA mutant exhibits growth defect upon entering the mid-log to stationary phase especially at high temperatures. Microscopic analysis further demonstrates that the absence of htrA induces extensive cell death. Additionally, the{Delta} htrA mutant has defects in cell locomotion as the expression of several key chemotaxis proteins are significantly downregulated. Cryo-electron tomography imaging of htrA mutant further reveals that deletion of htrA disrupts flagellar homeostasis. The failure of{Delta} htrA to establish an infection in mice is likely due to repressed expression of BosR and RpoS at the transcriptional level which ultimately causes dysregulation of the RpoS-induced virulence factors. Collectively, we conclude that the expression of htrA is finely tuned which is critical for its pleiotropic roles in the regulation of motility, stress response, and virulence gene expression in B. burgdorferi. IMPORTANCELyme borreliosis is the most commonly reported vector-borne illnesses in the United States, which is caused by Borrelia burgdorferi. As the enzootic pathogen alternates between the tick vector and mammalian hosts, adaptation to drastically different growth milieu is imperative to its survival. Hence, robust alteration of gene expression and proper quality control on protein synthesis and turnover are pivotal for its fitness. The family of HtrA serine proteases is mainly responsible for the maintenance of protein homeostasis particularly under stressful conditions. The significance of this report is to decode how BbHtrA contributes to the fitness of B. burgdorferi. BbHtrA is essential for mammalian host infection but little is known about its regulatory mechanism as well as its contribution to the virulence of B. burgdorferi. By deciphering the regulatory elements involved in the expression of BbHtrA, we are one step closer to comprehending its significance in the pathophysiology of B. burgdorferi.

microbiology↗

bioRxiv2024

Evaluating Methods for the Prediction of Cell Type-Specific Enhancers in the Mammalian Cortex

Identifying cell type-specific enhancers in the brain is critical to building genetic tools for investigating the mammalian brain. Computational methods for functional enhancer prediction have been proposed and validated in the fruit fly and not yet the mammalian brain. We organized the Brain Initiative Cell Census Network (BICCN) Challenge: Predicting Functional Cell Type-Specific Enhancers from Cross-Species Multi-Omics to assess machine learning and feature-based methods designed to nominate enhancer DNA sequences to target cell types in the mouse cortex. Methods were evaluated based on in vivo validation data from hundreds of cortical cell type-specific enhancers that were previously packaged into individual AAV vectors and retro-orbitally injected into mice. We find that open chromatin was a key predictor of functional enhancers, and sequence models improved prediction of non-functional enhancers that can be deprioritized as opposed to pursued for in vivo testing. Sequence models also identified cell type-specific transcription factor codes that can guide designs of in silico enhancers. This community challenge establishes a benchmark for enhancer prioritization algorithms and reveals computational approaches and molecular information that are crucial for identifying functional enhancers in mammalian cortical cell types. The results of this challenge bring us closer to understanding the complex gene regulatory landscape of the mammalian cortex and to designing more efficient genetic tools to target cortical cell types.

genomics↗