Search bioRxiv⌕ Search

Biology subjects

Chen, B.

Publications and source records attributed to Chen, B..

At least 217 records · Page 12Linked to original sources

Positive effects of tree diversity on tropical forest restoration in a field-scale experiment

Experiments under controlled conditions have established that ecosystem functioning is generally positively related to levels of biodiversity, but it is unclear how widespread these effects are in real-world settings and whether they can be harnessed for ecosystem restoration. We used a long-term, field-scale tropical restoration experiment to test how the diversity of planted trees affected recovery measured across a 500 ha area of selectively logged forest using multiple sources of satellite data. Replanting with species rich mixtures of tree seedlings that had higher phylogenetic and functional diversity accelerated restoration rates. Our results are consistent with a positive relationship between biodiversity and ecosystem functioning in the lowland dipterocarp rainforests of SE Asia and demonstrate that using diverse mixtures of species can enhance initial recovery after logging.

ecology↗

Tumor removal limits prostate cancer cell dissemination in bone cortex and osteoblasts induce cancer cell dormancy

BackgroundDisseminated tumor cells (DTCs) can enter a dormant state and cause no symptoms in cancer patients. On the other hand, the dormant DTCs can reactivate and cause metastases progression and lethal relapses. In prostate cancer (PCa), relapse can happen after curative treatments such as primary tumor removal. The impact of surgical removal on PCa dissemination and dormancy remains elusive. Furthermore, as dormant DTCs are asymptomatic, dormancy-inducing can be an operational cure for preventing metastases and relapse of PCa patients. MethodsWe used a PCa subcutaneous xenograft model and species-specific PCR to survey the DTCs in various organs at different time points of tumor growth and in response to tumor removal. We developed in vitro 2D and 3D co-culture models to recapitulate the dormant DTCs in the bone microenvironment. Proliferation assays, fluorescent cell cycle reporter, qRT-PCR, and Western Blot were used to characterize the dormancy phenotype. We performed RNA sequencing to determine the dormancy signature of PCa. A drug repurposing algorithm was applied to predict dormancy-inducing drugs and a top candidate was validated for the efficacy and the mechanism of dormancy induction. ResultsWe found DTCs in almost all mouse organs examined, including bones, at week 2 post-tumor cell injections. Surgical removal of the primary tumor reduced the overall DTC abundance, but the DTCs were enriched only in the bones. We found that osteoblasts, but not other cells of the bones, induced PCa cell dormancy. RNA-Seq revealed the suppression of mitochondrial-related biological processes in osteoblast-induced dormant PCa cells. Importantly, the mitochondrial-related biological processes were found up-regulated in both circulating tumor cells and bone metastases from PCa patients data. We predicted and validated the dormancy-mimicking effect of PF-562271, an inhibitor of focal adhesion kinase (FAK) in vitro. Decreased FAK phosphorylation and increased nuclear translocation were found in both co-cultured and PF-271-treated C4-2B cells, suggesting that FAK plays a key role in osteoblast-induced PCa dormancy. ConclusionsOur study provides the first insights into how primary tumor removal enriches PCa cell dissemination in the bones, defines a unique osteoblast-induced PCa dormancy signature, and identifies FAK as a PCa cell dormancy gatekeeper.

cancer biology↗

Targeting keratin 17-mediated reprogramming of de novo pyrimidine biosynthesis to overcome chemoresistance in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer death. We previously reported keratin 17 (K17) as a novel negative prognostic and predictive biomarker, whose overexpression confers the resistance to chemotherapies. Here, we investigated the mechanisms of chemoresistance and tumor-specific vulnerabilities that can be exploited for targeted therapies for K17-expressing PDAC. Unbiased metabolomic studies in isogenic PDAC models identified several key metabolic pathways that are upregulated in the presence of K17. We demonstrate that K17 increases pyrimidine biosynthesis, a pathway that has been linked to chemoresistance. Patient dataset analysis revealed that K17 expression and enzymes involved in pyrimidine, but not purine, de novo biosynthesis is associated with shorter patient survival. Rescue experiments showed that deoxycytidine (dC) and deoxythymidine (dT) were sufficient to promote resistance to Gemcitabine (a dC analog) and 5-fluorouracil (a dT analog), respectively. Furthermore, K17-expressing cells were more sensitive to Brequinar, a specific inhibitor of dihydroorotate dehydrogenase (DHODH), the rate-limiting enzyme in de novo pyrimidine biosynthetic pathway. Targeting DHODH by small interfering RNA or by Brequinar with Gemcitabine synergistically inhibited the viability of K17-positive PDAC cells. Importantly, the combination of Gemcitabine and Brequinar significantly inhibited the growth of K17-expressing tumors and extended survival of mice bearing K17-expressing PDACs. Overall, we identified a novel pathway of chemoresistance and a metabolic target of which could lead to the development of a biomarker-based therapy for K17-expressing PDAC.

cancer biology↗

IL-22/IL-22RA1 promotes human Tenon's capsule fibroblasts proliferation and regulates fibrosis through STAT3 signaling pathway

The study is aimed to investigate that the IL-22/IL-22RA1 signaling pathway regulates scar formation. A total of 31 glaucoma patients who had been previously treated with trabeculectomy surgery and the intraocular pressure was uncontrollable because of scarring and 19 strabismus patients as control patient group. ELISA showed that the IL-22 content of serum from glaucoma patients was 29.80{+/-}5.1 ng/l which is higher than that 5.21{+/-}0.9 ng/l from healthy group significantly. Serum from patients was used to incubate human Tenons capsule fibroblasts (HTFs) cells and IL-22 antibody rescued the effect of IL-22 on the biological functions. qPCR and western blot result showed that IL-22 mediates the biological function of HTFs cells via binding IL-22RA1 directly. When transfection of siR-IL-22RA1 or IL-22RA1 gene, the HTFs cells shown significantly anti-fibrosis or pro-fibrosis separately. By using STAT3 inhibitor BAY in IL-22RA1 overexpression group, IL-22-induced proliferation were reduced in HTFS cells. IL-22 promoted fibroblasts cell proliferation and -SMA via IL-22/IL-22RA1/STAT3 signaling pathway, thereby potentially regulating glaucoma filtration trace fibrosis. This results also show the novel factor in process of postoperative scarring. Summary StatementThe present study suggested that IL-22 expression in glaucoma patient after surgery. IL-22/IL-22RA1 signaling pathway promoted fibroblasts cell proliferation and -SMA by activating the STAT3 signaling pathway, thereby potentially regulating glaucoma filtration trace fibrosis.

cell biology↗

Identifying new regulators of evolutionarily conserved differential chromosome X dosage compensation

The active X chromosome in mammals is upregulated to balance its dosage to autosomes during evolution. However, it is elusive why the currently known dosage compensation machinery showed uneven and small influence on X genes, necessitating systemic investigation of X dosage in different angles and identification of new dosage regulators. Here, based on >20,000 transcriptomes, we identified two X gene groups (genome ploidy-sensitive [PSX] and ploidy-insensitive [PIX] genes), showing distinct but evolutionarily-conserved (in both primates and mouse) dosage compensations (termed X-over-Autosome dosage Ratio, or XAR). We then explored XAR in diseases and in stem cells, where XAR is potentially important. We demonstrated that XAR-PIX was downregulated while XAR-PSX upregulated across cancer types at both RNA and protein levels. In contrast, XAR-PIX was upregulated while XAR-PSX downregulated during stem cell differentiation. Interestingly, XAR-PIX, but not XAR-PSX, was significantly lower and associated with autoantibodies and inflammation in lupus patients, suggesting that insufficient dosage of PIX genes may contribute to lupus pathogenesis. We further identified and experimentally validated two new XAR regulators, TP53 and ATRX. Collectively, we provided insights to further unravel the mystery of X dosage compensation in mammals and its pathophysiological roles in human diseases.

cancer biology↗

Gamma-interferon-inducible lysosomal thiol reductase maintains cardiac immuno-metabolic homeostasis in heart failure

BackgroundThe lysosome is a central player in maintaining immuno-metabolic homeostasis. However, mechanistic insights into the regulation of lysosome-dependent immuno-metabolism in the heart are lacking. Lysosomal reductase Gamma Interferon-Inducible Thiol Reductase (GILT) is the only identified lysosomal reductase that controls diverse sets of lysosomal enzymes and cargoes. MethodsThe role of cardiac GILT was assessed by generating a novel genetic mouse model and employing a multidisciplinary approach including surgical interventions, live in situ high resolution microscopy, whole-tissue respirometry analysis, unbiased transcriptomic and metabolomic analyses, and various cell biology and biochemical assays. ResultsWe found that expression and activity of GILT are reduced in hearts from humans and mice with heart failure (HF). Mice with cardiac specific loss of GILT develop late onset systolic HF at baseline. In the setting of nutrient-overload and experimental left ventricular pressure overload conditions, loss of GILT in cardiomyocytes accelerates the development of heart dysfunction. Transcriptomic and metabolic analyses further revealed that cardiac GILT deficiency alters adaptive immuno-metabolic signatures in the heart. Finally, at the cellular level, cardiac GILT deletion impaired mitochondrial respiration, which was in part due to NLR Family Pyrin Domain Containing 3 (NLRP3)-mediated elevation of mitochondrial oxidative stress. ConclusionsTogether, these findings identify a causal link between a lysosome-inflammation axis, mitochondrial function and heart failure. Elucidation of these mechanisms will identify novel therapeutic strategies for treating HF.

molecular biology↗

PhiPipe: a multi-modal MRI data processing pipeline with test-retest reliability and predicative validity assessments

Magnetic Resonance Imaging (MRI) has been one of the primary instruments to measure the properties of the human brain non-invasively in vivo. MRI data generally needs to go through a series of processing steps (i.e., a pipeline) before statistical analysis. Currently, the processing pipelines for multi-modal MRI data are still rare, in contrast to single-modal pipelines. Furthermore, the reliability and validity of the output of the pipelines are critical for the MRI studies. However, the reliability and validity measures are not available or adequate for almost all pipelines. Here, we present PhiPipe, a multi-modal MRI processing pipeline. PhiPipe could process T1-weighted, resting-state BOLD, and diffusion-weighted MRI data and generate commonly used brain features in neuroimaging. We evaluated the test-retest reliability of PhiPipes brain features by computing intra-class correlations (ICC) in four public datasets with repeated scans. We further evaluated the predictive validity by computing the correlation of brain features with chronological age in three public adult lifespan datasets. The multi-variate reliability and predictive validity of the PhiPipe results were also evaluated. The results of PhiPipe were consistent with previous studies, showing comparable or better reliability and validity when compared with two popular single-modality pipelines, namely DPARSF and PANDA. The publicly available PhiPipe provides a simple-to-use solution to multi-modal MRI data processing. The accompanied reliability and validity assessments could help researchers make informed choices in experimental design and statistical analysis. Furthermore, this study provides a framework for evaluating the reliability and validity of image processing pipelines.

bioinformatics↗

Humanized antibody potently neutralizes all SARS-CoV-2 variants by a novel mechanism

SARS-CoV-2 Omicron variants have generated a world-wide health crisis due to resistance to most approved SARS-CoV-2 neutralizing antibodies and evasion of antibodies induced by vaccination. Here, we describe the SARS-CoV-2 neutralizing SP1-77 antibody that was generated from a humanized mouse model with a single human VH1-2 and V{kappa}1-33-associated with immensely diverse complementarity-determining-region-3 (CDR3) sequences. SP1-77 potently and broadly neutralizes SARS-CoV-2 variants of concern and binds the SARS-CoV-2 spike protein receptor-binding-domain (RBD) via a novel-CDR3-based mode. SP1-77 does not block RBD-binding to the ACE2-receptor or endocytosis step of viral entry, but rather blocks membrane fusion. Our findings provide the first mechanistic insight into how a non-ACE2 blocking antibody potently neutralizes SARS-CoV-2, which may inform strategies for designing vaccines that robustly neutralize current and future SARS-CoV-2 variants.

immunology↗

Sampling strategies and pre-pandemic surveillance gaps for bat coronaviruses

The emergence of SARS-CoV-2, and the challenge of pinpointing its ecological and evolutionary context, has highlighted the importance of evidence-based strategies for monitoring viral dynamics in bat reservoir hosts. Here, we compiled the results of 93,877 samples collected from bats across 111 studies between 1996 and 2018, and used these to develop an unprecedented open database, with over 2,400 estimates of coronavirus infection prevalence or seroprevalence at the finest methodological, spatiotemporal, and phylogenetic level of detail possible from public records. These data revealed a high degree of heterogeneity in viral prevalence, reflecting both real spatiotemporal variation in viral dynamics and the effect of variation in sampling design. Phylogenetically controlled meta-analysis revealed that the most significant determinant of successful viral detection was repeat sampling (i.e., returning to the same site multiple times); however, fewer than one in five studies longitudinally collected and reported data. Viral detection was also more successful in some seasons and from certain tissues, but was not improved by the use of euthanasia, indicating that viral detection may not be improved by terminal sampling. Finally, we found that prior to the pandemic, sampling effort was highly concentrated in ways that reflected concerns about zoonotic risk, leaving several broad geographic regions (e.g., South Asia, Latin America and the Caribbean, and most of Sub-Saharan Africa) and bat subfamilies (e.g., Stenodermatinae and Pteropodinae) measurably undersampled. These gaps constitute a notable vulnerability for global health security and will likely be a future barrier to contextualizing the origin of novel zoonotic coronaviruses.

ecology↗

Epac2 in midbrain dopamine neurons contributes to cocaine reinforcement via facilitation of dopamine release

Repeated exposure to drugs of abuse results in an upregulation of cAMP signaling in the mesolimbic dopamine system, a molecular adaptation thought to be critically involved in the development of drug dependence. Exchange protein directly activated by cAMP (Epac2) is a major cAMP effector abundantly expressed in the brain. However, it remains unknown whether Epac2 contributes to cocaine reinforcement. Here, we report that Epac2 in the mesolimbic dopamine system promotes cocaine reinforcement via enhancement of dopamine release. Conditional knockout of Epac2 from midbrain dopamine neurons (Epac2-cKO) and the selective Epac2 inhibitor ESI-05 decreased cocaine self-administration in mice under both fixed-ratio and progressive-ratio reinforcement schedules and across a broad range of cocaine doses. In addition, Epac2-cKO led to reduced evoked dopamine release, whereas Epac2 agonism robustly enhanced dopamine release in the nucleus accumbens in vitro. This mechanism is central to the behavioral effects of Epac2 disruption, as chemogenetic activation of ventral tegmental area (VTA) dopamine neurons increased dopamine release and reversed the impairment of cocaine self-administration in Epac2-cKO mice. Conversely, chemogenetic inhibition of VTA dopamine neurons reduced dopamine release and cocaine self-administration in wild-type mice. Epac2-mediated enhancement of dopamine release may therefore represent a novel and powerful mechanism that contributes to cocaine reinforcement.

neuroscience↗

Increasing the Field-of-View in Oblique Plane Microscopy via optical tiling

Fast volumetric imaging of large fluorescent samples with high-resolution is required for many biological applications. Oblique plane microscopy (OPM) provides high spatiotemporal resolution, but the field of view is typically limited by its optical train and the pixel number of the camera. Mechanically scanning the sample or decreasing the overall magnification of the imaging system can partially address this challenge, albeit by reducing the volumetric imaging speed or spatial sampling, respectively. In this Letter, we introduce a novel dual-axis scan unit for OPM that enables rapid and high-resolution volumetric imaging throughout a volume of 800 x 500 x 200 microns. This enables imaging of model organisms, such as zebrafish embryos, with subcellular resolution. Furthermore, we combined this microscope with a real-time and multi-perspective projection imaging technique to increase the volumetric interrogation rate to more than 10 Hz.

bioengineering↗

Redefining and subtyping of major depression based on brain functional connectivity signatures with high generalization: an ensemble hybrid framework

Current clinical diagnosis of major depression is solely based on subjective symptoms and signs rather than the underlying biological mechanisms, which has hindered the improvement in treatment effectiveness and outcomes. Redefining and subtyping major depressive disorder (MDD) based on neural circuits has been an emerging consensus. Here, we proposed a novel ensemble hybrid deep-learning framework based on graph neural network for redefining and subtyping of MDD with the brains "fingerprinting", i.e. nuanced functional connectivity profiles. A graph neural network (GNN) based supervised model was first employed to discriminate MDD patients from healthy controls. The graph embedding features obtained from the supervised classifier was then employed for subtyping of MDD with an unsupervised clustering by fast search and find of density peaks (CFDP) approach. The generalization accuracy and reproducibility of the proposed framework were further validated with one of the largest resting-state fMRI data set for MDD which included 2428 participants recruited from 25 independent sites. Our classifier showed a high generalization of 75% for leave-one-site-out cross validation. In addition, we obtained three biologically homogenous MDD subtypes characterized by impairments in subcortical-limbic, DMN-FPN, VN-SMN circuits, respectively. Notably, we demonstrated that subtyping of MDD according to graph embedding features showed high robustness and reproducibility across different sites. The proposed framework is not only essential for redefining and subtyping of MDD, but also paves the way towards precision medicine of mental disorders.

neuroscience↗

Targeting ATP12A, a non-gastric proton pump alpha subunit, for idiopathic pulmonary fibrosis treatment

Idiopathic Pulmonary Fibrosis (IPF) is a pathological condition of unknown etiology which results from injury to the lung and an ensuing fibrotic response that leads to thickening of the alveolar walls and obliteration of the alveolar space. The pathogenesis is not clear and there are currently no effective therapies for IPF. Small airway disease and mucus accumulation are prominent features in IPF lungs, similar to Cystic Fibrosis (CF) lung disease. The ATP12A gene encodes the alpha-subunit of the non-gastric H+, K+-ATPase, which functions to acidify the airway surface fluid and impairs mucociliary transport function in cystic fibrosis patients. We hypothesize that the ATP12A protein may play a role in the pathogenesis of IPF. Our studies demonstrate that ATP12A protein is overexpressed in distal small airways from IPF patient lungs compared to normal human lungs. In addition, overexpression of the ATP12A protein in mouse lungs worsened the bleomycin (BLEO)-induced experimental pulmonary fibrosis. This was prevented by a potassium-competitive proton pump blocker, vonoprazan (VON). This data supports the concept that the ATP12A protein plays an important role in the pathogenesis of lung fibrosis. Inhibition of the ATP12A protein has the potential as a novel therapeutic strategy in IPF.

cell biology↗

Spatial-ID: a cell typing method for spatially resolved transcriptomics via transfer learning and spatial embedding

Spatially resolved transcriptomics (SRT) provides the opportunity to investigate the gene expression profiles and the spatial context of cells in naive state. Cell type annotation is a crucial task in the spatial transcriptome analysis of cell and tissue biology. In this study, we propose Spatial-ID, a supervision-based cell typing method, for high-throughput cell-level SRT datasets that integrates transfer learning and spatial embedding. Spatial-ID effectively incorporates the existing knowledge of reference scRNA-seq datasets and the spatial information of SRT datasets. A series of quantitative comparison experiments on public available SRT datasets demonstrate the superiority of Spatial-ID compared with other state-of-the-art methods. Besides, the application of Spatial-ID on a SRT dataset with 3D spatial dimension measured by Stereo-seq shows its advancement on the large field tissues with subcellular spatial resolution.

genomics↗

TransCell: In silico characterization of genomic landscape and cellular responses from gene expressions through a two-step deep transfer learning

Gene expression profiling of new or modified cell lines becomes routine today; however, obtaining comprehensive molecular characterization and cellular responses for a variety of cell lines, including those derived from underrepresented groups, is not trivial when resources are minimal. Using gene expression to predict other measurements has been actively explored; however, systematic investigation of its predictive power in various measurements has not been well studied. We evaluate commonly used machine learning methods and present TransCell, a two-step deep transfer learning framework that utilizes the knowledge derived from pan-cancer tumor samples to predict molecular features and responses. Among these models, TransCell has the best performance in predicting metabolite, gene effect score (or genetic dependency), and drug sensitivity, and has comparable performance in predicting mutation, copy number variation, and protein expression. Notably, TransCell improved the performance by over 50% in drug sensitivity prediction and achieved a correlation of 0.7 in gene effect score prediction. Furthermore, predicted drug sensitivities revealed potential repurposing candidates for new 100 pediatric cancer cell lines, and predicted gene effect scores reflected BRAF resistance in melanoma cell lines. Together, we investigate the predictive power of gene expression in six molecular measurement types and develop a web portal (http://apps.octad.org/transcell/) that enables the prediction of 352,000 genomic and cellular response features solely from gene expression profiles. Key PointsO_LIWe provide a systematic investigation on evaluating the predictive power of gene expression in six molecular measurement types including protein expression, copy number variation, mutation, metabolite, gene effect score, and drug sensitivity. C_LIO_LITransCell took advantage of the transfer learning technique, showing how to learn knowledge from the source tumors, and transfer learned weight initializations to the downstream tasks in cell lines. C_LIO_LICompared to the baseline methods, TransCell outperformed in metabolite, gene effect score, and drug sensitivity predictions. C_LIO_LITwo cases studies demonstrate that TransCell could identify new repurposing candidates for pediatric cancer cell lines as well as capture the differences of genetic dependencies in melanoma resistant cell lines. C_LI

bioinformatics↗

Resolution doubling in light-sheet microscopy via oblique plane structured illumination

Structured illumination microscopy (SIM) doubles the spatial resolution of a fluorescence microscope without requiring high laser powers or specialized fluorophores. However, the excitation of out-of-focus fluorescence can accelerate photobleaching and phototoxicity. In contrast, light-sheet fluorescence microscopy (LSFM) largely avoids exciting out-of-focus fluorescence, thereby enabling volumetric imaging with low photo-bleaching and intrinsic optical sectioning. Combining SIM with LSFM would enable gentle 3D imaging at doubled resolution. However, multiple orientations of the illumination pattern, which are needed for isotropic resolution doubling in SIM, are challenging to implement in a light-sheet format. Here we show that multidirectional structured illumination can be implemented in oblique plane microscopy, a LSFM technique that uses a single objective for excitation and detection, in a straightforward manner. We demonstrate isotropic lateral resolution below 150nm, combined with lower photo-toxicity compared to traditional SIM systems and volumetric acquisition speed exceeding 1Hz.

biophysics↗

Exploring the mosquito-arbovirus network: a survey of vector competence experiments

Arboviruses receive heightened research attention during major outbreaks, or when they cause unusual or severe clinical disease, but are otherwise under-characterized. Global change is also accelerating the emergence and spread of arboviral diseases, leading to time sensitive questions about potential interactions between viruses and novel vectors. Vector competence experiments help determine the susceptibility of certain arthropods to a given arbovirus, but these experiments are often conducted in real-time during outbreaks, rather than with preparedness in mind. We conducted a systematic review of reported mosquito-arbovirus competence experiments, screening 570 abstracts to arrive at 265 studies testing in vivo arboviral competence. We found that over 90% of potential mosquito-virus combinations are untested in experimental settings, and that entire regions and their corresponding vectors and viruses are undersampled. These knowledge gaps stymie outbreak response, and limit attempts to both build and validate predictive models of the vector-virus network.

ecology↗

Altered Regulation of Ia Afferent Input during Voluntary Activity after Human Spinal Cord Injury

Sensory input converging on the spinal cord contributes to the control of voluntary activity. Although sensory pathways reorganize following spinal cord injury (SCI), the extent to which sensory input from Ia afferents is regulated during voluntary activity after the injury remains largely unknown. To address this question, we examined the soleus H-reflex and conditioning of the H-reflex by stimulating homonymous and heteronymous nerves [depression of the soleus H-reflex evoked by common peroneal nerve stimulation (D1 inhibition) and the monosynaptic Ia facilitation of the soleus H-reflex evoked by femoral nerve stimulation (FN facilitation)] at rest, and during tonic voluntary activity in humans with and without chronic incomplete SCI. We found that during voluntary activity the soleus H-reflex size increased in both groups compared with rest, but to a lesser extent in SCI participants. Compared with rest, the D1 inhibition decreased during voluntary activity in controls but it was still present in SCI participants. Further, the FN facilitation increased in controls but remained unchanged in SCI participants during voluntary activity compared with rest. Changes in the D1 inhibition and FN facilitation were correlated with changes in the H-reflex during voluntary activity, suggesting an association between outcomes. These findings provide the first demonstration that the regulation of Ia afferent input from homonymous and heteronymous nerves is altered during voluntary in humans with SCI, resulting in lesser facilitatory effect on motor neurons.

neuroscience↗