Biology subjects

Pei, Z.

Publications and source records attributed to Pei, Z..

At least 19 recordsLinked to original sources

bioRxiv2026

A UNIVERSAL FRAMEWORK FOR DISENTANGLING SUBJECT-SPECIFIC SIGNATURES IN EEG SIGNALS

Extracting stable subject-specific features from EEG signals remains challenging due to their entanglement with transient brain states. We propose a universal neural framework that disentangles subject-specific features from state-dependent components in raw EEG signals. Our approach employs a disentanglement module with a cross-reconstruction objective to isolate subject-specific representations. We validate our framework on EEG-based biometric recognition using two public datasets with leave-one-state-out cross-validation. Results demonstrate significant improvements in out-of-distribution identification accuracy across four different backbone models, confirming our methods universality and plug-and-play capability. This work advances reliable extraction of neural signatures for personalized neurotechnology applications.

neuroscience↗

bioRxiv2026

TAR syndrome causal gene RBM8A is critical for embryonic bone development and proper Hedgehog signaling

RNA-Binding Motif Protein 8A (RBM8A) is a core component of the exon junction complex (EJC), which plays a fundamental role in post-transcriptional RNA regulation. Mutations in the RBM8A gene cause thrombocytopenia-absent radius (TAR) syndrome, characterized by reduced platelet number and radial defects. However, how its function contributes to bone development remains poorly understood. We found that RBM8A is highly expressed in human bone marrow-derived mesenchymal stem cells (MSCs) and mouse embryonic limb buds. To further investigate the role of RBM8A in bone development, we generated an Rbm8a conditional knockout mouse (cKO) model in the early limb bud and craniofacial mesenchyme using the Prx1-cre line, which recapitulates key features of TAR syndrome. Rbm8a deficiency in this mouse model resulted in significant defects in limb and craniofacial development, including shorter limb bones across developmental timepoints, delayed ossification, altered cranial morphogenesis, along with impairments in motor function and reduced brain size. To elucidate the molecular basis of these phenotypes, we performed RNA immunoprecipitation sequencing (RIP-seq) in embryonic limb tissue. Our analysis revealed that RBM8A preferentially associates with long, exon-rich transcripts with high isoform complexity. These transcripts are enriched in pathways related to primary cilia, RNA processing, and developmental signaling. Consistent with this, transcriptomic and enrichment analyses identified strong associations with ciliopathy-related and congenital skeletal disease gene sets. At the cellular level, Rbm8a deficiency resulted in altered expression of key chondrogenic and ossification markers in embryonic limb bone tissue, such as reduced SOX9 and increased IHH in the primary ossification center, suggesting impaired progression of endochondral ossification and disrupted Hedgehog pathway activity. Quantitative Reverse Transcription-PCR (qRT-PCR) analysis further validated selective downregulation of Hedgehog pathway targets, including Gli3 and Hhip, while other developmental genes remained unchanged, indicating pathway-specific attenuation. Together, these findings support a model in which Rbm8a regulates structurally complex transcripts that are enriched in ciliary and developmental signaling pathways, and that disruption of this process leads to selective impairment of Hedgehog signaling and skeletal development. These results provide a novel mechanistic link between RNA processing and developmental signaling and offer new insight into how defects in RNA regulation contribute to congenital skeletal abnormalities.

developmental biology↗

bioRxiv2024

Role of ACSBG1 in brain lipid metabolism and X-linked adrenoleukodystrophy pathogenesis: Insights from a knockout mouse model

The "bubblegum" acyl-CoA synthetase (ACSBG1) is a pivotal player in lipid metabolism during the development of the mouse brain, facilitating the activation of long-chain fatty acids (LCFAs) and their integration into essential lipid species crucial for brain function. Through its enzymatic activity, ACSBG1 converts LCFAs into acyl-CoA derivatives, supporting vital processes like membrane formation, myelination, and energy production. Its regulatory role significantly influences neuronal growth, synaptic plasticity, and overall brain development, highlighting its importance in maintaining lipid homeostasis and proper brain function. Originally discovered in the fruit fly brain, ACSBG1 attracted attention for its potential implication in X-linked adrenoleukodystrophy (XALD) pathogenesis. Studies using Drosophila melanogaster lacking the ACSBG1 homolog, bubblegum, revealed adult neurodegeneration with elevated levels of very long-chain fatty acids (VLCFA). To explore ACSBG1s role in fatty acid (FA) metabolism and its relevance to XALD, we created an ACSBG1 knockout (Acsbg1-/-) mouse model and examined its impact on lipid metabolism during mouse brain development. Phenotypically, Acsbg1-/- mice resembled wild type (w.t.) mice. Despite its primary expression in tissues affected by XALD, brain, adrenal gland and testis, ACSBG1 depletion did not significantly reduce total ACS enzyme activity in these tissues when using LCFA or VLCFA as substrates. However, analysis unveiled intriguing developmental and compositional changes in FA levels associated with ACSBG1 deficiency. In the adult mouse brain, ACSBG1 expression peaked in the cerebellum, with lower levels observed in other brain regions. Developmentally, ACSBG1 expression in the cerebellum was initially low during the first week of life but increased dramatically thereafter. Cerebellar FA levels were assessed in both w.t. and Acsbg1-/- mouse brains throughout development, revealing notable differences. While saturated VLCFA levels were typically high in XALD tissues and in fruit flies lacking ACSBG1, cerebella from Acsbg1-/- mice displayed lower saturated VLCFA levels, especially after about 8 days of age. Additionally, monounsaturated {omega}9 FA levels exhibited a similar trend as saturated VLCFA, {omega}3 polyunsaturated FA levels werewhile elevated in Acsbg1-/- mice. Further analysis of specific FA levels provided additional insights into potential roles for ACSBG1. Notably, the decreased VLCFA levels in Acsbg1-/- mice primarily stemmed from changes in C24:0 and C26:0, while reduced {omega}9 FA levels were mainly observed in C18:1 and C24:1. ACSBG1 depletion had minimal effects on saturated long-chain FA or {omega}6 polyunsaturated FA levels but led to significant increases in specific {omega}3 FA, such as C20:5 and C22:5. Moreover, the impact of ACSBG1 deficiency on the developmental expression of several cerebellar FA metabolism enzymes, including those required for synthesis of {omega}3 polyunsaturated FA, was assessed; these FA can potentially be converted into bioactive signaling molecules like eicosanoids and docosanoids. In conclusion, despite compelling circumstantial evidence, it is unlikely that ACSBG1 directly contributes to the pathology of XALD. Instead, the effects of ACSBG1 knockout on processes regulated by eicosanoids and/or docosanoids should be further investigated.

biochemistry↗

bioRxiv2024

Molecular stratification of human fetal vaginal epithelium by spatial transcriptome analysis

The human vaginal epithelium is a crucial component in numerous reproductive processes and serves as a vital protective barrier against pathogenic invasion. Despite its significance, a comprehensive exploration of its molecular profiles, including molecule expression and distribution across its multiple layers, remains elusive. In our study, we undertook a spatial transcriptomic analysis within the vaginal wall of human fetuses to fill this knowledge gap. We successfully categorized vaginal epithelium into four distinct zones based on their transcriptomic profiles and anatomical features. This approach unveiled unique transcriptomic signatures within these regions, allowing us to identify differentially expressed genes and uncover novel markers for distinct regions of the vaginal epithelium. Additionally, our findings have highlighted the varied expression of KRT genes across different zone of the vaginal epithelium, with a gradual shift in expression patterns observed from the basal layer to the surface/superficial layer. This suggests a potential differentiation trajectory of human vaginal epithelium, shedding light on the dynamic nature of this tissue. Furthermore, abundant biological processes were found to be enriched in the basal zone by the KEGG pathway analysis, indicating an active state of the basal zone cells. Subsequently, the expression of latent stem cell markers in the basal zone were identified. In summary, our research provides crucial understanding of human vaginal epithelial cells and the complex mechanisms of the vaginal mucosa, with potential applications in vaginal reconstruction and drug delivery, making this atlas a valuable tool for future research in womens health and reproductive medicine.

cell biology↗

bioRxiv2023

Multi-omics features-based machine learning method improve immunotherapy response in clear cell renal cell carcinoma

Programmed cell death 1 (PD-1) or PD-ligand 1 (PD-L1) blocker-based strategies have improved the survival outcomes of clear cell renal cell carcinomas (ccRCCs) in recent years, but only a small number of patients have benefited from them. In this study, we identified three inflammatory features through over 1900 autoimmune nephropathy patients-related bulk RNA sequencing, single-cell RNA sequencing analysis, and three immunogenic signatures using genomics (TIs), both of which are associated with response to immune checkpoint blocks (ICBs) and the survival of ccRCC patients. Here, we developed a framework with a TIs-based machine learning approach to accurately predict ICB efficacy. We enrolled more than 1000 ccRCC patients with ICB treatment from five cohorts to apply the model and demonstrated its excellent specificity and robustness. Moreover, our model outperforms well-known ICB predictive biomarkers such as tumor mutational burden (TMB), PD-L1 expression, and tumor immune microenvironment (TME). Overall, the TIs-ML model provides a novel method for guiding precise immunotherapy in ccRCC.

bioinformatics↗

bioRxiv2023

Targeting CD301+ macrophage inhibits endometrial fibrosis and improves pregnancy outcome

Macrophages are a key and heterogeneous cell population involved in endometrial repair and regeneration during the menstrual cycle, but their role in the development of intrauterine adhesion (IUA) and sequential endometrial fibrosis remains unclear. Here, we reported that CD301+ macrophages were significantly increased and showed their most active interaction with profibrotic cells in the endometria of IUA patients compared with the normal endometria by single-cell RNA sequencing, bulk RNA sequencing and experimental verification. Increasing CD301+ macrophages promoted the differentiation of endometrial stromal cells into myofibroblasts and resulted in extracellular matrix accumulation, which destroyed the physiological architecture of endometrial tissue, drove endometrial fibrosis and ultimately led to female infertility or adverse pregnancy outcomes. Mechanistically, CD301+ macrophages secreted GAS6 to activate the AXL/NF-{kappa}B pathway, up-regulating the profibrotic protein synthesis. Targeted deletion of CD301+ macrophages or inhibition of AXL by Bemcentinib blunted the pathology and improved the outcomes of pregnancy in mice, supporting the therapeutic potential of targeting CD301+ macrophages for treating endometrial fibrosis.

immunology↗

bioRxiv2023

Stanniocalcin 2 (STC2) is a potent biomarker of hepatocellular carcinoma with its expression being augmented in Nrf1α-deficient cells, but diminished in Nrf2-deficient cells

For insights into the fact that liver-specific knockout of Nrf1 leads to development of non-alcoholic steatohepatitis and spontaneous hepatoma, we previously found that loss of Nrf1 (i.e., a full-length isoform encoded by Nfe2l1) promotes HepG2-derived tumor growth in xenograft mice, but malgrowth of the xenograft tumor is significantly suppressed by knockout of Nrf2 (encoded by Nfe2l2). The mechanism underlying such marked distinctions in their pathologic phenotypes remains elusive, however, to date. Herein, we mined the transcriptome data of liver cancer from the TCGA database to establish a prognostic model of liver cancer and then calculated the predicted risk score of each cell line. The results indicated that knockout of Nrf1 significantly increased the risk score in HepG2 cells, whereas the risk score was reduced by knockout of Nrf2. Of note, stanniocalcin 2 (STC2, a biomarker of liver cancer, that is up-expressed in hepatocellular carcinoma (HCC) tissues with a reduction in the overall survival ratio of those patients) was augmented in Nrf1Nrf2-/- cells, but diminished in Nrf2-/- cells. Thereby, it is inferable that STC2 is likely involved in mediating the distinction between Nrf1Nrf2-/- and Nrf2-/-. Further investigation revealed that HIF1A is an upstream regulator of STC2 in caNrf2{Delta}N, rather than Nrf1Nrf2-/-, cells, and regulation of STC2 and HIF1A in Nrf1Nrf2-/- is determined by Nrf2, but the regulation of STC2 by Nrf2 may be independent on HIF1A. In turn, STC2 can regulate Nrf2 via the putative calcium-mediated Keap1-p62 signaling so to form a feedback regulatory loop. Such potential function of STC2 was further corroborated by a series of experiments combined with transcriptomic sequencing. The results unraveled that STC2 manifests as a dominant tumor-promoter, because the STC2-leading increases in clonogenicity of hepatoma cells and malgrowth of relevant xenograft tumor were almost completely abolished in STC2-/-cells. Together, these demonstrate that STC2 could be paved as a novel potent therapeutic target, albeit as a diagnostic marker, for hepatocellular carcinoma.

cell biology↗

bioRxiv2023

VERY LONG-CHAIN ACYL-CoA SYNTHETASE-3 (ACSVL3) PROMOTES THE MALIGNANT GROWTH BEHAVIOR OF U87 GLIOMA CELLS VIA CHANGES IN CELL CYCLE WITHOUT AFFECTING APOPTOSIS

Decreasing the expression of very long-chain acyl-CoA synthetase 3 (ACSVL3) in U87MG glioblastoma cells by either RNA interference or genomic knockout (KO) significantly decreased their growth rate in culture, as well as their ability to form rapidly growing tumors in mice. U87-KO cells grew at a 9-fold slower rate than U87MG cells. When injected subcutaneously in nude mice, the tumor initiation frequency of U87-KO cells was 70% of that of U87MG cells, and the average growth rate of tumors that did form was decreased by 9-fold. Two hypotheses to explain the decreased growth rate of KO cells were investigated. Lack of ACSVL3 could reduce cell growth either by increasing apoptosis, or via effects on the cell cycle. We examined intrinsic, extrinsic, and caspase-independent apoptosis pathways; none were affected by lack of ACSVL3. However, significant differences in the cell cycle were seen in KO cells, suggesting arrest in S-phase. Levels of cyclin-dependent kinases 1, 2, and 4 were elevated in U87-KO cells, as were regulatory proteins p21 and p53 that promote cell cycle arrest. In contrast, lack of ACSVL3 reduced the level of the inhibitory regulatory protein p27. {gamma}-H2AX, a marker of DNA double strand breaks, was elevated in U87-KO cells, while pH3, a mitotic index marker, was reduced. Previously reported alterations in sphingolipid metabolism in ACSVL3-depleted U87 cells may explain the effect of KO on cell cycle. These studies reinforce the notion that ACSVL3 is a promising therapeutic target in glioblastoma.

biochemistry↗

bioRxiv2022

ACSF2: A MEDIUM-CHAIN ACYL-CoA SYNTHETASE WITH A POTENTIAL ROLE IN NEURONAL DIFFERENTIATION

By activating fatty acids to their CoA derivatives, acyl-CoA synthetases (ACS) play an essential role in fatty acid metabolism. We previously identified ACSF2 as an ACS that was phylogenetically distinct from known families of short-chain, medium-chain, long-chain, very long-chain, and bubblegum ACSs. Functionally, ACSF2 preferentially activated medium-chain fatty acids. In this work, we provide further characterization of this unique ACS. ACSF2 mRNA expression was found in most tissues, although immunohistochemical analysis revealed differences in protein expression between various cell types in each tissue. Endogenous ACSF2 was found in the Golgi region in Neuro2a and P19 cells, and disruption of the Golgi in Neuro2a cells with nocodazole disrupted ACSF2 localization. In contrast, MA-10, HepG2, and skin fibroblasts had a mitochondrial ACSF2 localization. ACSF2 activated saturated fatty acids containing 6 to 10 carbons when overexpressed in COS-1 cells. The Kmapp for C10:0 was 24.4 M and Vmaxapp was 385 nmol/20min/mg COS cell protein. Knockdown by RNA interference revealed that ACSF2 was responsible for most of the medium-chain ACS activity in Neuro2a cells. A lysine residue critical for activity in bacterial short-chain ACSs was found in ACSF2, and mutation of this residue to alanine abolished enzyme activity. Neurite outgrowth results when Neuro2a cells are induced to differentiate with retinoic acid, and ACSF2 migrated to nodes and points of neurite-neurite contact along with the presynaptic marker, synaptophysin. ACSF2-deficient Neuro2a cells showed significantly blunted neurite outgrowth in response to retinoic acid. These results suggest that this medium-chain ACS may play an important role in neuronal development.

biochemistry↗

bioRxiv2021

Cell transcriptomic atlas of the non-human primate Macaca fascicularis

Studying tissue composition and function in non-human primates (NHP) is crucial to understand the nature of our own species. Here, we present a large-scale single-cell and single-nucleus transcriptomic atlas encompassing over one million cells from 43 tissues from the adult NHP Macaca fascicularis. This dataset provides a vast, carefully annotated, resource to study a species phylogenetically close to humans. As proof of principle, we have reconstructed the cell-cell interaction networks driving Wnt signalling across the body, mapped the distribution of receptors and co-receptors for viruses causing human infectious diseases and intersected our data with human genetic disease orthologous coordinates to identify both expected and unexpected associations. Our Macaca fascicularis cell atlas constitutes an essential reference for future single-cell studies in human and NHP.

cell biology↗

bioRxiv2021

CD147 antibody specifically and effectively inhibits infection and cytokine storm of SARS-CoV-2 variants

SARS-CoV-2 and its variants are raging worldwide. Unfortunately, the global vaccination is not efficient enough to attain a vaccine-based herd-immunity and yet no special and effective drug is developed to contain the spread of the disease. Previously we have identified CD147 as a novel receptor for SARS-CoV-2 infection. Here, we demonstrated that CD147 antibody effectively inhibits infection and cytokine storm caused by SARS-CoV-2 variants. In CD147KO VeroE6 cells, infections of SARS-CoV-2, its variants (B.1.1.7, B.1.351) and pseudovirus mutants (B.1.1.7, B.1.351, B.1.525, B.1.526 (S477N), B.1.526 (E484K), P.1, P.2, B.1.617.1, B.1.617.2) were decreased. Meanwhile, CD147 antibody effectively blocked the entry of variants and pseudomutants in VeroE6 cells, and inhibited the expression of cytokines. A model of SARS-CoV-2-infected hCD147 transgenic mice was constructed, which recapitulated the features of exudative diffuse alveolar damage and dynamic immune responses of COVID-19. CD147 antibody could effectively clear the virus and alveolar exudation, resolving the pneumonia. We found the elevated level of cyclophilin A (CyPA) in plasma of severe/critical cases, and identified CyPA as the most important proinflammatory intermediate causing cytokine storm. Mechanistically, spike protein of SARS-CoV-2 bound to CD147 and initiated the JAK-STAT pathway, which induced expression of CyPA. CyPA reciprocally bound to CD147, triggered MAPK pathway and consequently mediated the expression of cytokine and chemokine. In conclusion, CD147 is a critical target for SARS-CoV-2 variants and CD147 antibody is a promising drug to control the new wave of COVID-19 epidemic.

immunology↗

bioRxiv2021

Isolation of sensory hair cell specific exosomes in human perilymph

Evaluation of hearing loss patients using clinical audiometry has been unable to give a definitive cellular or molecular diagnosis, hampering the development of treatments of sensorineural hearing loss. However, biopsy of inner ear tissue without losing residual hearing function for pathologic diagnosis is extremely challenging. In a clinical setting, perilymph can be accessed, so alternative methods for molecular characterization of the inner ear may be developed. Recent approaches to improving inner ear diagnostics have been focusing on the evaluation of the proteomic or miRNA profiles of perilymph. Inspired by recent characterization and classification of many neurodegenerative diseases using exosomes which not only are produced in locally in diseased tissue but are transported beyond the blood brain barrier, we demonstrate the isolation of human inner ear specific exosomes using a novel ultrasensitive immunomagnetic nano pom-poms capture-release approach. Using perilymph samples harvested from surgical procedures, we were able to isolate exosomes from sensorineural hearing loss patients in only 2-5 L of perilymph. By isolating sensory hair cell derived exosomes through their expression level of myosin VII, we for the first time sample material from hair cells in the living human inner ear. This work sets up the first demonstration of immunomagnetic capture-release nano pom-pom isolated exosomes for liquid biopsy diagnosis of sensorineural hearing loss. With the ability to isolate exosomes derived from different cell types for molecular characterization, this method also can be developed for analyzing exosomal biomarkers from more accessible patient tissue fluids such as plasma.

neuroscience↗

bioRxiv2020

Co-opting regulation bypass repair (CRBR) as a gene correction strategy for monogenic diseases

With the development of CRISPR/Cas9-mediated gene editing technologies, correction of disease- causing mutations has become possible. However, current gene correction strategies preclude mutation repair in post-mitotic cells of human tissues, and a unique repair strategy must be designed and tested for each and every mutation that may occur in a gene. We have developed a novel gene correction strategy, Co-opting Regulation Bypass Repair (CRBR), which can repair a spectrum of mutations in mitotic or post-mitotic cells and tissues. CRBR utilizes the non-homologous end-joining (NHEJ) pathway to insert a coding sequence (CDS) and transcription/translation terminators targeted upstream of any CDS mutation and downstream of the transcriptional promoter. CRBR gene repair results in simultaneous co-option of the endogenous regulatory region and bypass of the genetic defect. We demonstrated the potential of CRBR strategy for human gene therapy by rescuing a mouse model of the Wolcott-Rallison syndrome (WRS) with permanent neonatal diabetes caused by either large deletion or nonsense mutation in the PERK (EIF2AK3) gene. Additionally, we expressed a GFP CDS-terminator cassette that was integrated downstream of the human insulin promoter in cadaver pancreatic islets of Langerhans which paves the way for autologous cell-tissue replacement therapy for gene repair in beta cells.

genetics↗

bioRxiv2020

Transcription factor-based gene therapy to treat glioblastoma through direct neuronal conversion

Glioblastoma (GBM) is the most prevalent and aggressive adult primary cancer in the central nervous system (CNS). Therapeutic approaches for glioblastoma are under intense investigation, such as the emerging immunotherapy, but so far only marginal progress has been made due to the heterogeneity and highly invasive nature of glioblastoma. Here, we propose an alternative approach to tackle GBM through reprogramming proliferative GBM cells into non-proliferative neurons. We report efficient neuronal conversion from human GBM cells by overexpressing single neural transcription factor Neurogenic differentiation 1 (NeuroD1), Neurogenin-2 (Neurog2) or Achaete-scute homolog 1 (Ascl1). Subtype characterization reveals that the majority of Neurog2- and NeuroD1-converted neurons are glutamatergic, while Ascl1 favors GABAergic neuron generation. The GBM cell-converted neurons not only express pan-neuronal markers, such as NeuN and MAP2, but also exhibit neuron-specific electrophysiological activities. We further conducted transcriptome analyses to investigate the underlying cell conversion mechanism. Our RNA-seq analyses discover that neuronal genes are activated among glioma cells after overexpression of neural transcription factors, and different signaling pathways are activated by different neural transcription factors. Importantly, the neuronal conversion of GBM cells is accompanied by significant inhibition of GBM cell proliferation in both in vitro and in vivo models. Therefore, these results suggest that GBM cells can be reprogrammed into different subtypes of neurons, leading to a potential alternative approach to treat brain tumor. SignificanceConverting dividing glioblastoma cells into non-dividing neurons may provide an innovative therapeutic approach to treat glioblastoma. HighlightsO_LIEfficient neuronal conversion of human glioblastoma cells achieved by overexpression of neural transcription factors C_LIO_LINeurog2- and NeuroD1-converted neurons are mostly glutamatergic, while Ascl1-converted neurons are mainly GABAergic C_LIO_LITranscriptome analyses reveal the activation of neuronal genes after overexpression of neural transcription factors in glioblastoma cells C_LIO_LIInhibition of cell proliferation during glioblastoma cell conversion both in vitro and in vivo C_LI

neuroscience↗

bioRxiv2020

Glutamate and γ-aminobutyric acid differentially modulate glymphatic clearance of amyloid β through pulsation- and aquaporin-4 dependent mechanisms

The glymphatic system contributes to a large proportion of brain waste clearance, including removal of amyloid {beta} (A{beta}). We have demonstrated that glutamate and {gamma}-aminobutyric acid (GABA) influence glymphatic clearance through distinct mechanisms whereby GABA exerts modulatory effects in an aquaporin-4 (AQP4)-dependent manner while the actions of glutamate are pulsation-dependent. The efficacy of GABA and glutamate in alleviating A{beta} in APP-PS1 and Angiotensin-II (Ang-II) induced hypertension mouse models was further evaluated. Notably, increasing GABA or inhibiting glutamate levels led to reduced binding of A{beta} to pre-labeled plaques to similar extents in APP-PS1 mice while GABA appeared more efficient in A{beta} clearance in hypertensive animals than the glutamate inhibitor. Our findings support the modulation of neurotransmitters that influence the glymphatic pathway via distinct mechanisms as a potentially effective therapeutic strategy for clearance of A{beta} deposits from the brain.

neuroscience↗

bioRxiv2018

Functional repair after ischemic injury through high efficiency in situ astrocyte-to-neuron conversion

Mammalian brains have largely lost internal neural regeneration capability except for a few discrete neurogenic niches. After brain injury, the cerebral cortex is especially difficult to repair due to its extremely low rate of adult neurogenesis. Previous studies have converted glial cells into neurons, but the total number of neurons generated is rather limited, casting doubt about its therapeutic potential. Here, we demonstrate that high-efficiency neuroregeneration can be achieved in adult mammalian brains by making use of an engineered AAV Cre-FLEX system to convert a large number of reactive astrocytes into functional neurons. Specifically, using a combination of GFAP::Cre and FLEX-NeuroD1 AAV system, we were able to regenerate enough new neurons from astrocytes to cover about 40% of the neurons lost from an ischemic injury (400 NeuN+ new neurons/mm2), compared to previously reported an average of <1% of cortical neurons (2-8 NeuN+ neurons/mm2) in an ischemic-injured adult mammalian cortex. Importantly, this in situ astrocyte-to-neuron conversion process also improved survival of injured pre-existing neurons, (additional 400 neurons/mm2), leading to a repaired motor cortex with layered cortical structures. Moreover, NeuroD1-converted neurons not only form functional neural circuits but also rescue motor and memory deficits after ischemic injury. Our results establish the proof-of-principle that a highly efficient in situ astrocyte-to-neuron conversion approach provides a novel treatment for neurological disorders that are in need of new neurons.

neuroscience↗

bioRxiv2018

Reversing Glial Scar Back To Neural Tissue Through NeuroD1-Mediated Astrocyte-To-Neuron Conversion

Nerve injury often causes neuronal loss and glial proliferation, disrupting the delicate balance between neurons and glial cells in the brain. Recently, we have developed an innovative technology to convert internal reactive glial cells into functional neurons inside the mouse brain. Here, we further demonstrate that such glia-to-neuron conversion can rebalance neuron-glia ratio and reverse glial scar back to neural tissue. Specifically, using a severe stab injury model in the mouse cortex, we demonstrated that ectopic expression of NeuroD1 in reactive astrocytes significantly reduced glial reactivity and transformed toxic A1 astrocytes into less harmful astrocytes before neuronal conversion. Importantly, astrocytes were not depleted after neuronal conversion but rather repopulated due to its intrinsic proliferation capability. Remarkably, converting reactive astrocytes into neurons also significantly reduced microglia-mediated neuroinflammation. Moreover, accompanying regeneration of new neurons together with repopulation of new astrocytes, blood-brain-barrier was restored and synaptic density was rescued in the injury sites. Together, these results demonstrate that glial scar can be reversed back to neural tissue through rebalancing neuron:glia ratio after glia-to-neuron conversion.

neuroscience↗

bioRxiv2017

HPViewer: Sensitive and specific genotyping of human papillomavirus in metagenomic DNA

BackgroundShotgun DNA sequencing provides sensitive detection of all 182 HPV types in tissue and body fluid. However, existing computational methods either produce false positives misidentifying HPV types due to shared sequences among HPV, human, and prokaryotes, or produce false negative since they identify HPV by assembled contigs requiring large abundant of HPV reads.\n\nResultsWe show that HPV shares extensive simple repeats with human and prokaryotes and homologous sequences among different HPV types. The shared sequences caused errors in HPV genotyping and the repeats of human origin caused false positives in HPVDetector. Programs, such as VirusTAP and Vipie, which require de novo assembly of shotgun reads into contigs, eliminated false positives at a cost of substantial reduction in sensitivity. Here, we designed HPViewer with two custom HPV reference databases masking simple repeats and homology sequences respectively and one homology distance matrix to hybridize these two databases. It directly identified HPV from short DNA reads rather than assembled contigs. Using 100,100 simulated samples, we revealed that HPViewer was robust for samples containing either high or low number of HPV reads. Using 12 shotgun sequencing samples from respiratory papillomatosis, HPViewer was equal to VirusTAP, and Vipie and better than HPVDetector with the respect to specificity and was the most sensitive method in the detection of HPV types 6 and 11. We demonstrated that contigs-based approaches had disadvantages of detection of HPV. In 1,573 sets of metagenomic data from 18 human body sites, HPViewer identified 104 types of HPV in a body-site associated pattern and 89 types of HPV co-occurring in one sample with other types of HPV at least once.\n\nConclusionsWe demonstrated HPViewer was sensitive and specific for HPV detection in metagenomic data. It was also suggested that masking shared sequences is an effective approach to avoid false positive detection and identifying HPV from short metagenomic reads is more sensitive than assembled contigs. The innovative homology distance matrix connecting two HPV databases, repeat-mask and homology-mask, optimized the balance of sensitivity and specificity. HPViewer can be accessed at https://github.com/yuhanH/HPViewer/.

bioinformatics↗