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Yang, M.

Publications and source records attributed to Yang, M..

At least 253 records · Page 14Linked to original sources

Best Practices for Interpretable Machine Learning in Computational Biology

Advances in machine learning (ML) have enabled the development of next-generation prediction models for complex computational biology problems. These developments have spurred the use of interpretable machine learning (IML) to unveil fundamental biological insights through data-driven knowledge discovery. However, in general, standards and guidelines for IML usage in computational biology have not been well-characterized, representing a major gap toward fully realizing the potential of IML. Here, we introduce a workflow on the best practices for using IML methods to perform knowledge discovery which covers verification strategies that bridge data, prediction model, and explanation. We outline a workflow incorporating these verification strategies to increase an IML methods accountability, reliability, and generalizability. We contextualize our proposed workflow in a series of widely applicable computational biology problems. Together, we provide an extensive workflow with important principles for the appropriate use of IML in computational biology, paving the way for a better mechanistic understanding of ML models and advancing the ability to discover novel biological phenomena.

bioinformatics↗

Alveolar epithelial type 1 cells serve as a cell of origin for lung adenocarcinoma with distinct molecular and phenotypic presentation

Lung adenocarcinoma (LUAD) is the most common subtype of cancer arising in the distal lung. LUAD encompasses several pathologic subtypes, each with differing clinical outcomes and biological behaviors. However, the molecular and cellular underpinnings of the different subtypes are largely unknown. Understanding which cell populations in the distal lung contribute to LUAD could provide insights into the marked heterogeneity in pathologic features, clinical presentation and responses to therapy of LUAD. Differential expression analysis of lung adenocarcinoma transcriptomes from The Cancer Genome Atlas revealed distinct alveolar epithelial type 1 (AT1) and alveolar epithelial type 2 (AT2) cell signatures within human LUAD with significantly different survival outcomes between tumors expressing AT2 and AT1 gene signatures, suggesting AT1 cells might contribute to a subset of LUAD cases. To address this, we tested the ability of AT1 cells to give rise to LUAD following induction of KrasG12D, a known oncogenic driver of human LUAD. Activation of KrasG12D in Gram-domain containing 2 (Gramd2)+ AT1 cells gave rise to multiple LUAD lesions, primarily of papillary histology. In contrast, activation of KrasG12D in surfactant protein C (Sftpc+) AT2 cells resulted in LUAD lesions of lepidic histology. Immunohistochemistry established that Gramd2:KrasG12D lesions were of primary lung origin and not metastatic events. Spatial transcriptomic profiling revealed distinct pathway alterations within Gramd2- and Sftpc-derived LUAD. Immunofluorescence confirmed differences observed in the spatial transcriptomic analysis in expression patterns and distribution of cell-specific markers depending on cell of origin, while universal upregulation of the Krt8 intermediate cell state marker was observed. Our results are consistent with Gramd2+ AT1 cells serving as a putative cell of origin for LUAD and suggest that LUAD may be a collection of adenocarcinomas that share a common location within the distal lung but arise from different cells of origin.

cancer biology↗

Intranasal delivery of NS1-deleted influenza virus vectored COVID-19 vaccine restrains the SARS-CoV-2 inflammatory response

The emergence of SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2) variants and "anatomical escape" characteristics threaten the effectiveness of current coronavirus disease (COVID-19) vaccines. There is an urgent need to understand the immunological mechanism of broad-spectrum respiratory tract protection to guide broader vaccines development. In this study, we investigated immune responses induced by an NS1-deleted influenza virus vectored intranasal COVID-19 vaccine (dNS1-RBD) which provides broad-spectrum protection against SARS-CoV-2 variants. Intranasal delivery of dNS1-RBD induced innate immunity, trained immunity and tissue-resident memory T cells covering the upper and lower respiratory tract. It restrained the inflammatory response by suppressing early phase viral load post SARS-CoV-2 challenge and attenuating pro-inflammatory cytokine (IL-6, IL-1B, and IFN-{gamma}) levels, thereby reducing excess immune-induced tissue injury compared with the control group. By inducing local cellular immunity and trained immunity, intranasal delivery of NS1-deleted influenza virus vectored vaccine represents a broad-spectrum COVID-19 vaccine strategy to reduce disease burden.

immunology↗

Targeting Fusobacterium nucleatum through Chemical Modifications of Host-Derived Transfer RNA Fragments

Host mucosal barriers possess an arsenal of defense molecules to maintain mucosal health. In addition to well-established defense molecules such as antimicrobial peptides and immunoglobulins, a subset of extracellular host-derived small RNAs (sRNAs) also exhibits antimicrobial functions in a cross-kingdom fashion. We recently uncovered the sRNA-mediated crosstalk between human normal oral keratinocytes and Fusobacterium nucleatum (Fn), an opportunistic oral pathobiont with increasing implications in extra-oral diseases. Notably, when challenged with Fn, oral keratinocytes released Fn-targeting tRNA-derived sRNAs (tsRNAs), an emerging class of noncoding sRNAs with diverse functions in gene regulation. Additionally, synthetic mimics of the Fn-targeting tsRNAs exhibited highly selective antimicrobial activity against Fn. However, excess synthetic tsRNAs (in the micromolar range) were required to achieve growth inhibition, which limits their potential as antimicrobials. Here, we chemically modify nucleotides of the anti-Fn tsRNAs, termed MOD-tsRNAs, and demonstrate their species- and sequence-specific inhibition in the nanomolar range in various Fn type strains and clinical tumor isolates. In contrast, the same MOD-tsRNAs do not inhibit two representative oral bacteria, Porphoromonas gingivalis (Pg) and Streptococcus mitis (Sm). Additionally, MOD-tsRNAs are internalized by different Fn strains while exhibiting minimal uptake by Pg and Sm. Further RNA sequencing and affinity pull-down assays implicate MOD-tsRNAs as potential ribosome-targeting antimicrobials against Fn. Taken together, our work provides a framework to target opportunistic pathobionts through co-opting host-derived extracellular tsRNAs, whose potential applications may have been limited by their intrinsic instability as well as our limited understanding of the inhibition mechanism.

bioengineering↗

eccDB: a comprehensive repository for eccDNA-mediated chromatin contacts in multi-species

The role of extrachromosomal circular DNA (eccDNA) has been highlighted. More recently, eccDNA-chromosome interactions were identified, suggesting a potential role of eccDNA in transcriptional regulation. Several databases currently provide valuable resources for the study of eccDNAs. However, these databases are primarily focused on Human eccDNAs and do not provide analysis of eccDNA-chromosome interaction and eccDNA gene expression in different tissues. Herein, to further integrate available resources for eccDNA data across multiple species, we developed the eccDB database. The current version of eccDB has collected a total of 1,317,182 eccDNAs in 424 samples from four species (homo sapiens, mus musculus, saccharomyces cerevisiae, and arabidopsis thaliana). eccDB provides regulatory and epigenetic information on eccDNA, including typical enhancers, super-enhancers, transcription factors, DNA methylation positions, risk SNPs, expression quantitative trait locus, chromatin accessibility regions, and chromHMM states. In particular, eccDB provides eccDNAs intrachromosomal and interchromosomal interaction analysis to predict the transcriptional regulatory functions of eccDNA. Moreover, eccDB identifies eccDNAs from unknown DNA sequences and analyzes the functional and evolutionary relationships of an eccDNA among different species. Overall, eccDB offers web-based analytical tools and a comprehensive resource for biologists and clinicians to decipher the molecular regulatory mechanisms of eccDNA. eccDB is freely available at http://www.xiejjlab.bio/eccDB

bioinformatics↗

The Role of Frontal Eye Field in Saccadic Mixed-strategy Decision-making

Game theory can predict the distribution of choices in aggregate during mixed-strategy games, yet the neural process mediating individual probabilistic choices remains poorly understood. Here, we examined the role of frontal eye field (FEF) in a decision-making task when macaques were trained to play a mixed-strategic game - Matching Pennies - against a computer opponent. Neuronal activities of FEF neurons predicted the animals upcoming saccadic choices and these activities became increasingly more selective as the choice deadline approached. Subthreshold electrical micro-stimulation applied in FEF also biased choices. Extended stimulation biased choices towards the preferred FEF vector whereas early termination of stimulation biased choices away from the preferred FEF vector. By contrast, micro-stimulation biased choices in the preferred direction during a non-strategic perceptual luminance discrimination task. We conclude that FEF is causally contributing to mixed-strategy decision-making process although the timing of FEF activation contributes to the decision process in a more non-linear manner during strategic compared to perceptual decision-making.

neuroscience↗

Genetic control of RNA editing in Neurodegenerative disease

A-to-I RNA editing diversifies human transcriptome to confer its functional effects on the downstream genes or regulations, potentially involving in neurodegenerative pathogenesis. Its variabilities are attributed to multiple regulators, including the key factor of genetic variant. To comprehensively investigate the potentials of neurodegenerative disease-susceptibility variants from the view of A-to-I RNA editing, we analyzed matched genetic and transcriptomic data of 1,596 samples across nine brain tissues and whole blood from two large consortiums, Accelerating Medicines Partnership - Alzheimers Disease (AMP-AD) and Parkinsons Progression Markers Initiative (PPMI). The large-scale and genome-wide identification of 95,637 RNA editing quantitative trait loci revealed the preferred genetic effects on adjacent editing events. Furthermore, to explore the underlying mechanisms of the genetic controls of A-to-I RNA editing, several top RNA binding proteins were pointed out, such as EIF4A3, U2AF2, NOP58, FBL, NOP56, and DHX9, since their regulations on multiple RNA editing events probably interfered by these genetic variants. Moreover, these variants may also contribute to the variability of other molecular phenotypes associated with RNA editing, including the functions of four proteins, expressions of 148 genes, and splicing of 417 events. All the analyses results shown in NeuroEdQTL (https://relab.xidian.edu.cn/NeuroEdQTL/) constituted a unique resource for the understanding of neurodegenerative pathogenesis from genotypes to phenotypes related to A-to-I RNA editing.

bioinformatics↗

Structural and mechanistic insights into inhibition of the type I-F CRISPR-Cas surveillance complex by AcrIF4

CRISPR-Cas system provides prokaryotes with protection against mobile genetic elements (MGEs) such as phages. In turn, phages deploy anti-CRISPR (Acr) proteins to evade this immunity. AcrIF4, an Acr targeting the type I-F CRISPR-Cas system, has been reported to bind the crRNA-guided surveillance (Csy) complex. However, it remains controversial whether AcrIF4 inhibits target DNA binding to the Csy complex. Here, we present structural and mechanistic studies into AcrIF4, exploring its unique anti-CRISPR mechanism. While the Csy-AcrIF4 complex displays decreased affinity for target DNA, it is still able to bind the DNA. Structural and functional analyses of the Csy-AcrIF4-dsDNA complex revealed that AcrIF4 binding prevents rotation of the helical bundle (HB) of Cas8f induced by dsDNA binding, therefore resulting in failure of Cas2/3 recruitment and DNA cleavage. Overall, our study provides an interesting example of attack on the nuclease recruitment event by an Acr, but not conventional mechanisms of blocking binding of target DNA.

molecular biology↗

Structural and functional insights into the type III-E CRISPR-Cas immunity

The type III-E CRISPR-Cas system comprises a Cas effector (gRAMP), a TPR-CHAT and several ancillary proteins. However, both the structural features of gRAMP and the immunity mechanism remain unknown for this system. Here, we report a series of structures of gRAMP-crRNA, either its alone or in complex with target RNA or TPR-CHAT (called Craspase), and Craspase complexed with cognate (CTR) or non-cognate target RNA (NTR). Importantly, the 3 anti-tag region of NTR and CTR bind at two distinct channels in the Craspase, and CTR with a non-complementary 3 anti-tag induces a marked conformational change of the TPR-CHAT, which allosterically activates its protease activity to cleave an ancillary protein Csx30. This cleavage then triggers an abortive infection as the antiviral strategy of the type III-E system. Together, our study provides crucial insights into both the catalytic mechanism of the gRAMP and the immunity mechanism of the type III-E CRISPR-Cas system.

molecular biology↗

Labeled lines for fat and sugar reward combine to promote overeating

Food is a powerful natural reinforcer that guides feeding decisions. The vagus nerve conveys internal sensory information from the gut to the brain about nutritional value; however, the cellular and molecular basis of macronutrient-specific reward circuits are poorly understood. Here, we monitor in vivo calcium dynamics to provide direct evidence of independent vagal sensing pathways for detection of dietary fats and sugars. Using activity-dependent genetic capture of nutrient-specific vagal neurons activated in response gut infusions, we demonstrate the existence of separate hard-wired reward circuits for fat and sugar that are necessary and sufficient for nutrient-specific reinforcement. Even when controlling for calories, combined activation of fat and sugar circuits increases overeating compared to fat or sugar alone. This work provides new insight on the complex sensory circuitry that mediates motivated behavior and suggests that a subconscious internal drive to consume obesogenic diets (e.g., those high in both fat and sugar) may impede conscious dieting efforts.

neuroscience↗

Genetic disruption of isocitrate dehydrogenase arrests the full development of sexual stage parasites in Plasmodium falciparum

The malaria parasites encode all eight mitochondrial enzymes that can constitute the classical tricarboxylic acid (TCA) cycle. We previously reported that genetic ablation of six out of eight TCA enzymes had no significant impact on the parasite survival and growth in asexual blood stage; aconitase knockout ({Delta}ACO) parasites were, however, arrested as late-stage gametocytes. Herein, we describe a defective gametocyte development phenotype resulting from the knockout of another TCA enzyme, isocitrate dehydrogenase (IDH). Similar to the{Delta} ACO gametocytes,{Delta} IDH gametocytes stall at stage III/IV and cannot form mature gametocytes or undergo exflagellation. Both ACO and IDH KO gametocytes exhibit fragmented mitochondrial morphology. Knockout of IDH also exerts a fitness cost, leading to a decrease in growth rate in erythrocytic stages. We examined two possible causes for the phenotype in the{Delta} IDH gametocytes: 1. Accumulation of reactive oxygen species (ROS) within the parasite mitochondrion due to diminished production of mitochondrial NADPH during the 10-14 days of gametocyte development; or 2. Cytotoxicity of built-up citrate upstream of IDH. We found that antioxidant agents such as N-acetylcysteine and MitoQ did not rescue the phenotype of{Delta} ACO or{Delta} IDH gametocytes. Large amounts of citrate in the medium also had no significant effect on the gametocyte development or gamete formation of wildtype parasites. Our results demonstrate the importance of IDH in gametocytogenesis, providing evidence that IDH as well as aconitase could be further explored as targets for gametocidal agents and malaria transmission blockers.

microbiology↗

Machine Learning Informs RNA-Binding Chemical Space

Small molecule targeting of RNA has emerged as a new frontier in medicinal chemistry, but compared to the protein targeting literature our understanding of chemical matter that binds to RNA is limited. In this study, we report Repository Of BInders to Nucleic acids (ROBIN), a new library of nucleic acid binders identified by small molecule microarray (SMM) screening. The complete results of 36 individual nucleic acid SMM screens against a library of 24,572 small molecules are reported (including a total of 1,627,072 interactions assayed). A set of 2,003 RNA-binding small molecules is identified, representing the largest fully public, experimentally derived library of its kind to date. Machine learning is used to develop highly predictive and interpretable models to characterize RNA-binding molecules. This work demonstrates that machine learning algorithms applied to experimentally derived sets of RNA binders are a powerful method to inform RNA-targeted chemical space.

biochemistry↗

Digitally Predicting Protein Localization and Manipulating Protein Activity in Fluorescence Images Using Four-dimensional Reslicing GAN

MotivationWhile multi-channel fluorescence microscopy is a vital imaging method in biological studies, the number of channels that can be imaged simultaneously is limited by technical and hardware limitations such as emission spectra cross-talk. One feasible solution is using deep neural networks to model the localization relationship between two proteins so that the localization of a protein can be digitally predicted. Furthermore, the input and predicted localization implicitly reflects the modeled relationship. Accordingly, observing the predictions via repeatedly manipulating input localizations is an explainable and feasible way to analyze the modeled relationships between the input and the predicted proteins. ResultsWe propose a Protein Localization Prediction (PLP) method using a cGAN named Four-dimensional Reslicing Generative Adversarial Network (4DR-GAN) to digitally generate additional channels. 4DR-GAN models the joint probability distribution of imaged and target proteins by simultaneously incorporating the protein localization signals in four dimensions including space and time. Because protein localization often correlates with protein activation state, with accurate PLP, we further propose two novel tools: digital activation (DA) and digital inactivation (DI) to digitally activate and inactivate a protein and observe the response of the predicted protein localization. Compared with genetic approaches, these tools allow precise spatial and temporal control. A comprehensive experiment on four groups of proteins shows that 4DR-GAN achieves higher-quality PLP than Pix2Pix and the DA and DI responses are consistent with the known protein functions. The proposed PLP method helps simultaneously visualize additional proteins and DA and DI provide guidance to study localization-based protein functions. Availability and ImplementationThe open-source code is at https://github.com/YangJiaoUSA/4DR-GAN.

bioinformatics↗

Anti-apoptotic BH3-only proteins inhibit Bak

Bcl-2 family proteins regulate induction of intrinsic apoptosis through initiating mitochondrial outer membrane permeabilization (MOMP). Activation of the MOMP effectors Bax and Bak is controlled by interplay levels of anti-apoptotic Bcl-2 proteins (e.g. Mcl-1) and pro-apoptotic BH3-only proteins (e.g. BIM). Using a genome-wide CRISPR-dCas9 transactivation screen we identified two Bcl-2 family proteins, BNIP5 and Bcl-G, as inhibitors of Bak, but not Bax induced apoptosis. BNIP5 was able to block Bak activation in different cell types and in response to various cytotoxic therapies. The BH3 domain of BNIP5 was both necessary and sufficient to block Bak activation. Mechanistically, the BH3 domains of BNIP5 and Bcl-G act as a selective Bak activators, while not inhibiting anti-apoptotic proteins. This led to increased binding of activated Bak to Mcl-1, which prevented apoptosis engagement, identifying BNIP5 and Bcl-G as anti-apoptotic BH3-only proteins.

cell biology↗

FOXA2 controls the antioxidant response in FH-deficient cells independent of NRF2

Hereditary Leiomyomatosis and renal cell cancer (HLRCC) is a cancer syndrome caused by inactivating germline mutations in fumarate hydratase (FH) and subsequent accumulation of fumarate. Fumarate accumulation leads to the activation of an anti-oxidant response via nuclear translocation of the transcription factor NRF2. The activation of the anti-oxidant response is key for cellular survival in FH-deficient cells, yet the extent to which chromatin remodelling shapes the anti-oxidant response is currently unknown. Here, we explored the global effects of FH loss on the chromatin landscape to identify transcription factor networks involved in the highly remodelled chromatin landscape of FH-deficient cells. We identify FOXA2 as a key transcription factor which directly regulates anti-oxidant response genes and subsequent metabolic rewiring. Moreover, we also find that FOXA2 regulates anti-oxidant genes independent of the canonical anti-oxidant regulator NRF2. The identification of FOXA2 as an anti-oxidant regulator provides new insights into the molecular mechanisms behind cell responses to fumarate accumulation, and potentially provides new avenues for therapeutic intervention for HLRCC.

cancer biology↗

A Novel Selective ERK1/2 Inhibitor, Laxiflorin B, Targets EGFR Mutation Subtypes in Non-small-cell Lung Cancer

Extracellular regulated protein kinases 1/2 (ERK1/2) are key members of multiple signaling pathways including the ErbB axis. ERK1/2 ectopic activation is responsible for various types of cancer, especially drug resistance to inhibitors of RTK, RAF and MEK, but specific ERK1/2 inhibitors are scarce. In this study, we identified a potential novel ERK covalent inhibitor, Laxiflorin B, a herbal compound with anticancer activity. However, Laxiflorin B is present at low levels in herbs; therefore, we adopted a semi-synthetic process for the efficient production of Laxiflorin B to improve the yield. Laxiflorin B induced mitochondria-mediated apoptosis via BAD activation in non-small-cell lung cancer (NSCLC) cells, especially in EGFR mutant subtypes. Transcriptomic analysis suggested that Laxiflorin B inhibits amphiregulin (AREG) and epiregulin (EREG) expression through ERK inhibition, and suppressed the activation of their receptors, ErbBs, via a positive feedback loop. More importantly, mass spectrometry combined with computer simulation analysis revealed that Laxiflorin B binds covalently to Cys-183 in the ATP-binding pocket of ERK1 through D-ring, and Cys-178 of ERK1 though non-inhibitory binding of A-ring, respectively. Laxiflorin B also exhibited strong tumor suppressive effects with low toxicity in a NSCLC tumor xenograft model in nude mice, and AREG and EREG were identified as biomarkers of Laxiflorin B efficacy. Finally, Laxiflorin B-4, a C-6 modification of Laxiflorin B, exhibited higher affinity for ERK1/2 and stronger tumor suppression. These findings provide a new approach to tumor inhibition using natural anticancer compounds.

pharmacology and toxicology↗

The mechanosensitive ion channel Piezo1 modulates the migration and immune response of microglia

Microglia are the brains resident immune cells, performing surveillance to promote homeostasis and healthy functioning. While chemical signaling in microglia is well-studied, the mechanical cues regulating their function are less well-understood. Here, we investigate the role of the mechanosensitive ion channel Piezo1 in microglia migration, pro-inflammatory cytokine production and stiffness sensing. We demonstrated the functional expression of Piezo1 in microglia and identified genes whose expression was affected by conditional Piezo1 knockout in transgenic mice. Functional assays revealed that Piezo1-deficiency in microglia enhanced migration towards amyloid {beta}-protein, and decreased levels of pro-inflammatory cytokines produced upon stimulation by lipopolysaccharide, both in vitro and in vivo. The phenomenon could be mimicked or reversed using a Piezo1-specific agonist or antagonist. Finally, we also showed that Piezo1 mediated the effect of substrate stiffness-induced migration and cytokine expression. Altogether, we show that Piezo1 is an important molecular mediator for microglia, its activation modulating their migration and immune responses.

neuroscience↗

HIRA loss transforms FH-deficient cells

Fumarate Hydratase (FH) is a mitochondrial enzyme that catalyses the reversible hydration of fumarate to malate in the TCA cycle. Germline mutations of FH lead to HLRCC, a cancer syndrome characterised by a highly aggressive form of renal cancer(1). Although HLRCC tumours metastasise rapidly, FH-deficient mice develop premalignant cysts in the kidneys, rather than carcinomas (2). How Fh1-deficient cells overcome these tumour suppressive events during transformation is unknown. Here, we perform a genome-wide CRISPR/Cas9 screen to identify genes that, when ablated, enhance the proliferation of Fh1-deficient cells. We found that the depletion of HIRA enhances proliferation and invasion of Fh1-deficient cells in vitro and in vivo. Mechanistically, Hira loss enables the activation of MYC and its target genes, increasing nucleotide metabolism specifically in Fh1-deficient cells, independent of its histone chaperone activity. These results are instrumental for understanding mechanisms of tumorigenesis in HLRCC and the development of targeted treatments for patients.

cancer biology↗