Biology subjects

Xiong, Y.

Publications and source records attributed to Xiong, Y..

At least 109 records · Page 6Linked to original sources

bioRxiv2024

The transcription factor ZNF469 regulates collagen production in liver fibrosis

Non-alcoholic fatty liver disease (NAFLD) - characterized by excess accumulation of fat in the liver - now affects one third of the worlds population. As NAFLD progresses, extracellular matrix components including collagen accumulate in the liver causing tissue fibrosis, a major determinant of disease severity and mortality. To identify transcriptional regulators of fibrosis, we computationally inferred the activity of transcription factors (TFs) relevant to fibrosis by profiling the matched transcriptomes and epigenomes of 108 human liver biopsies from a deeply-characterized cohort of patients spanning the full histopathologic spectrum of NAFLD. CRISPR-based genetic knockout of the top 100 TFs identified ZNF469 as a regulator of collagen expression in primary human hepatic stellate cells (HSCs). Gain- and loss-of-function studies established that ZNF469 regulates collagen genes and genes involved in matrix homeostasis through direct binding to gene bodies and regulatory elements. By integrating multiomic large-scale profiling of human biopsies with extensive experimental validation we demonstrate that ZNF469 is a transcriptional regulator of collagen in HSCs. Overall, these data nominate ZNF469 as a previously unrecognized determinant of NAFLD-associated liver fibrosis.

molecular biology↗

bioRxiv2024

A high-continuity and annotated reference genome of allotetraploid Siberian wildrye (Elymus sibiricus L., Poaceae: Triticeae)

Elymus sibiricus L. (Siberian wildrye, Es), a species belonging to the wheat tribe, is extensively employed as forage and for the reclamation of degraded grasslands within the Qinghai-Tibet Plateau (QTP). This study provides a high-quality reference genome assembly for the allotetraploid Es, which is composed of 14 pseudomolecules with the total genome size of 6.57 Gb. Our finding suggest that large-scale bursts of retrotransposons are critical for the genome expansion of Es. We discovered a translocation event between the Es4H and Es6H chromosomes with a low frequency of combination. Phylogenetic analyses of 90 Es accessions and 25 diploid accessions representing proposed ancestors from various habitats revealed the existence of four distinct populations. We further provided support for the hypothesis that the QTP is the center of origin and genetic diversity for Es. Collectively, our study offers valuable insights into the evolution of Es, as well as providing genomic resources for genetic enhancement in the Elymus genus and wheat tribe.

genomics↗

bioRxiv2024

Bioluminescence Imaging of Potassium Ion Using a Sensory Luciferin and an Engineered Luciferase

Bioluminescent indicators are power tools for studying dynamic biological processes. In this study, we present the generation of novel bioluminescent indicators by modifying the luciferin molecule with an analyte-binding moiety. Specifically, we have successfully developed the first bioluminescent indicator for potassium ions (K+), which are critical electrolytes in biological systems. Our approach involved the design and synthesis of a K+-binding luciferin named potassiorin. Additionally, we engineered a luciferase enzyme called BRIPO (bioluminescent red indicator for potassium) to work synergistically with potassiorin, resulting in optimized K+-dependent bioluminescence responses. Through extensive validation in cell lines, primary neurons, and live mice, we demonstrated the efficacy of this new tool for detecting K+. Our research demonstrates an innovative concept of incorporating sensory moieties into luciferins to modulate luciferase activity. This approach has great potential for developing a wide range of bioluminescent indicators, advancing bioluminescence imaging (BLI), and enabling the study of various analytes in biological systems. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/581057v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@1ffeb68org.highwire.dtl.DTLVardef@b83871org.highwire.dtl.DTLVardef@81b34corg.highwire.dtl.DTLVardef@1224b0b_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2024

Discovery of the First-in-class G9a/GLP PROTAC Degrader

Aberrantly expressed lysine methyltransferases G9a and GLP, which catalyze mono- and di-methylation of histone H3 lysine 9 (H3K9), have been implicated in numerous cancers. Recent studies have uncovered both catalytic and non-catalytic oncogenic functions of G9a/GLP. As such, G9a/GLP catalytic inhibitors have displayed limited anticancer activity. Here, we report the discovery of the first-in-class G9a/GLP proteolysis targeting chimera (PROTAC) degrader, 10 (MS8709), as a potential anticancer therapeutic. 10 induces G9a/GLP degradation in a concentration-, time, and ubiquitin-proteasome system (UPS)-dependent manner, does not alter the mRNA expression of G9a/GLP and is selective for G9a/GLP over other methyltransferases. Moreover, 10 displays superior cell growth inhibition to the parent G9a/GLP inhibitor UNC0642 in prostate, leukemia, and lung cancer cells and has suitable mouse pharmacokinetic properties for in vivo efficacy studies. Overall, 10 is a valuable chemical biology tool to further investigate the functions of G9a/GLP and a potential therapeutic for treating G9a/GLP-dependent cancers. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=127 SRC="FIGDIR/small/582210v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@1b3c923org.highwire.dtl.DTLVardef@5a22f0org.highwire.dtl.DTLVardef@1abbabeorg.highwire.dtl.DTLVardef@1711f29_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2024

Stabilization of Integrator/INTAC by the small but versatile DSS1 protein

Integrator-PP2A (INTAC) is a highly modular complex orchestrating the transition of paused RNA polymerase II into productive elongation or promoter-proximal premature termination, with its loss resulting in transcription dysregulation and genome instability. Here, we identify human DSS1--a flexible 70-residue protein found in multiple functionally diverse complexes including the 26S proteasome--as an integral subunit of the INTAC backbone. Structural analysis of DSS1-INTAC, both alone and in association with paused polymerase, demonstrates intimate interactions between DSS1 and the INTAC backbone subunit INTS7. We identify tryptophan 39 of DSS1 as being critical for interacting with INTAC and find that mutating this residue disrupts DSS1s interaction with INTAC, while maintaining DSS1s interaction with the proteasome. This substitution not only destabilizes INTAC and therefore INTAC-dependent transcriptional regulation, but also reveals that INTAC is DSS1s major chromatin-bound form. Together, our findings reveal the essential role of the versatile DSS1 protein in the structure and regulatory functions of INTAC.

molecular biology↗

bioRxiv2024

Differences in milk microbiota between healthy cows and cows with recurring Klebsiella mastitis

Klebsiella spp. infections continue to have a significant economic impact on the dairy industry, being an important cause of severe clinical mastitis, recurrent infections, and demonstrating poor response to antimicrobials. It is, therefore, essential to investigate the underlying causes of Klebsiella spp. infections. Here we used high-throughput DNA sequencing to characterize the milk microbiota of healthy dairy cows (HDC) and cows with history of recurrent Klebsiella mastitis (KLB). Our goal was to identify potential pathogenic genera associated with recurrent Klebsiella infections in cows. The relative abundance of Firmicutes and Faecalibacterium was greater in the KLB group than in the HDC group. In contrast, Proteobacteria and Labrenzia were less abundant than in the HDC group. Although the species distributions differed between groups, diversity and abundance of communities were comparable. Notably, genera of increased occurrence in the KLB group were mostly intestinal-associated, which suggests that cows in the KLB group resided in a contaminated environment or had increased teat-end exposure to fecal bacteria. We did not detect major differences in microbiota among quarters, and also between fore-strip milk and milk collected after fore-stripping. Conversely, milk of heifers had increased alpha diversity in comparison to milk of multiparous cows.

microbiology↗

bioRxiv2024

PI3Kγ promotes neutrophil extracellular trap formation by noncanonical pyroptosis in abdominal aortic aneurysm

BackgroundAbdominal aortic aneurysm (AAA) is one of the most life-threatening cardiovascular diseases while currently lacks effective drug treatment. NETs formation has been proved to be crucial trigger of AAA, so finding its upstream regulatory targets is the key to discovering therapeutic agents for AAA. Methods and Resultswe reveal that PI3Kgmma (PI3K{gamma}) is an upstream signal that regulates NETs formation. Inhibition of PI3K{gamma} reduces the expression of NETs and reduces inflammation in the aortic wall, thereby significantly ameliorating AAA. However, the mechanism of NETs formation regulated by PI3K{gamma} has not been fully elucidated. Using isolated bone marrow neutrophils, we show that PI3K{gamma} deficiency inactivates the noncanonical pyroptosis pathway (Capase11/GSDMD) to inhibit NETs expression, and subsequently found that PI3K{gamma} regulation of noncanonical pyroptosis via anchoring PKA is dependent on cAMP/PKA signaling, but not on classical PI3K/AKT signaling. ConclusionsOur research uncovers the role and mechanism of PI3K{gamma} in AAA development and provides insights into AAA therapy from the perspective of NETs formation.

cell biology↗

bioRxiv2024

AFM-RL: Large Protein Complex Docking Using AlphaFold-Multimer and Reinforcement Learning

Various biological processes in living cells are carried out by protein complexes, whose interactions can span across multiple protein structures. To understand the molecular mechanisms of such processes, it is crucial to know the quaternary structures of these complexes. Although the structures of many protein complexes have been determined through biophysical experiments, there are still many important complex structures that are yet to be determined, particularly for large complexes with multiple chains. To supplement experimental structure determination, many computational protein docking methods have been developed, but most are limited to two chains, and few are designed for three chains or more. We have previously developed a method, RL-MLZerD, for multiple protein docking, which was applied to complexes with three to five chains. Here, we expand the ability of this method to predict the structures of large protein complexes with six to twenty chains. We use AlphaFold-Multimer (AFM) to predict pairwise models and then assemble them using our reinforcement learning framework. Our new method, AFM-RL, can predict a diverse set of pairwise models, which aids the RL assembly steps for large protein complexes. Additionally, AFM-RL demonstrates improved modeling performance when compared to existing methods for large protein complex docking.

bioinformatics↗

bioRxiv2023

Distance-AF: Modifying Predicted Protein Structure Models by Alphafold2 with User-Specified Distance Constraints

The three-dimensional structure of a protein plays a fundamental role in determining its function and has an essential impact on understanding biological processes. Despite significant progress in protein structure prediction, such as AlphaFold2, challenges remain on those hard targets that Alphafold2 does not often perform well due to the complex folding of protein and a large number of possible conformations. Here we present a modified version of the AlphaFold2, called Distance-AF, which aims to improve the performance of AlphaFold2 by including distance constraints as input information. Distance-AF uses AlphaFold2s predicted structure as a starting point and incorporates distance constraints between amino acids to adjust folding of the protein structure until it meets the constraints. Distance-AF can correct the domain orientation on challenging targets, leading to more accurate structures with a lower root mean square deviation (RMSD). The ability of Distance-AF is also useful in fitting protein structures into cryo-electron microscopy maps.

bioinformatics↗

bioRxiv2023

USP7 Inhibition Promotes Mesenchymal Stem cell-Macrophage Crosstalk in Age-related Osteoporosis via Efferocytosis and Senolysis

Although elderly osteoporotic patients have similar implant survival rates compared to those of normal individuals, they require longer healing periods to achieve proper osseointegration. This may be related to chronic inflammatory responses and impaired stem cell repair functions in the osteoporotic bone microenvironment. Recently, the deubiquitinating enzyme, ubiquitin-specific peptidase 7 (USP7), was found to regulate macrophage immune response and modulate stem cell osteogenic differentiation. The selective inhibitor of USP7, P5091, has also been found to promote bone repair and homeostasis in osteoporotic conditions. However, the roles of USP7 and P5091 in osteoimmunology and dental implant osseointegration under senile osteoporotic conditions remain unclear. In this study, USP7 depletion and P5091 were showed to inhibit inflammation in senescent bone marrow derived macrophages (BMDMs) and promote osteogenic differentiation in aged BMSCs. Furthermore, mRNA-Seq revealed that USP7 depletion could enhance efferocytosis in senescent BMDMs through the EPSIN1/ low-density lipoprotein receptor-related protein 1 (LRP1) pathway and selectively induce apoptosis (senolysis) in aged BMSCs. In senile osteoporotic mice, we found that the osseointegration period was prolonged compared to young mice, and P5091 promoted the early stage of osseointegration, which may be related to macrophage efferocytosis around the implant. Collectively, this study suggests that USP7 inhibition may accelerate the osseointegration process in senile osteoporotic conditions by promoting macrophage efferocytosis and aged BMSCs apoptosis. This has implications for understanding the cellular interactions and signaling mechanisms in the peri-implant bone microenvironment under osteoporotic conditions. It may also provide clinical significance in developing new therapies to enhance osseointegration quality and shorten the edentulous period in elderly osteoporotic patients.

cell biology↗

bioRxiv2023

Diet-induced obesity results in endothelial cell desensitization to VEGF-A and permanent islet vascular dysfunction

BackgroundPancreatic islet microvasculature is essential for optimal islet function and glucose homeostasis. However, islet vessel pathogenesis and its role in the manifestation of metabolic disorders remain understudied. Here we depict a time-resolved decline of intra-islet endothelial cell sensitivity to vascular endothelial cell growth factor A (VEGF-A) in a mouse model of diet-induced obesity. MethodsMice were transplanted with reporter islets in their eyes and put on different diet schemes for 48 weeks. Islet vascular morphology, VEGF-A signaling activity in islet endothelial cells and vessel function were longitudinally monitored by in vivo imaging, while the metabolic implication of islet vessel alterations was measured by glucose tolerance tests and insulin secretion assays. ResultsIn parallel with substantial islet vasculature remodeling, diminished VEGF-A response in islet endothelial cells emerged after 12 weeks of western diet feeding. This led to vessel barrier dysfunction and hemodynamic dysregulation, which delayed transportation of secreted insulin into the blood. Islet vessels also exhibited a remarkable metabolic memory long after the removal of western diet. Neither islet endothelial cell VEGF-A sensitivity nor the vascular damage elicited by 24 weeks of western diet feeding was restored by switching to control diet for another 24 weeks. As a result, these refed mice still exhibited mild but significant impairment in glucose clearance, despite a complete normalization of body weight and insulin sensitivity. While plasma levels of soluble VEGF receptor 1 - the natural VEGF-A trap - were similar in all diet groups, increased activity of atypical protein kinase C (aPKC) was observed under both western diet and recovery conditions, which inhibited VEGF receptor 2 (VEGFR2) internalization and dampened VEGF-A triggered signal transduction in vivo and in human endothelial cells cultured under diet-mimicking conditions. ConclusionsLong-term western diet feeding causes irreversible VEGF-A desensitization in islet endothelial cells and islet vessel dysfunction which undermines glucose homeostasis.

physiology↗

bioRxiv2023

TFEB degradation is regulated by an IKK/β-TrCP2 phosphorylation-ubiquitination cascade

Transcription factor EB (TFEB) is a master regulator of lysosomal biogenesis and autophagy that plays a key role in the regulation of cellular clearance pathways. TFEB is regulated via a complex array of post-translational modifications (PTMs), but the exact molecular mechanism that regulates TFEB stability has remained elusive. Here, we show that TFEB levels are critically regulated by a defined phosphorylation-ubiquitination cascade. A human kinome screen identifies IKK (inhibitor of {kappa}B kinase) as a TFEB modifier, and a combination of phosphorylation assays, mass spectrometry analyses, and site-specific mutagenesis unveils a previously unrecognized TFEB phospho-degron (423SPFPSLS429) as the target of IKK. We show that IKK-mediated phosphorylation of TFEB triggers ubiquitination of adjacent lysine residues (K430 and K431) by the E3 ligase {beta}-TrCP2 ({beta}-Transducin repeat-containing protein 2), thereby tagging TFEB for degradation. Modified TFEB constructs that abolish these PTMs show much increased stability and expression levels but remain equally sensitive to autophagy- or stress- related stimuli while maintaining the capability to promote the expression of TFEB target genes and the clearance of Alzheimers associated tau in a cellular model of disease. Our results therefore uncover an IKK/{beta}-TrCP2 phosphorylation-ubiquitination cascade as a major mechanism that governs TFEB stability independently of other TFEB regulators.

cell biology↗

bioRxiv2023

Propofol-mediated loss of consciousness disrupts predictive routing and local field phase modulation of neural activity

Predictive coding is a fundamental function of the cortex. The predictive routing model proposes a neurophysiological implementation for predictive coding. Predictions are fed back from deep-layer cortex via alpha/beta (8-30Hz) oscillations. They inhibit the gamma (40-100Hz) and spiking that feed sensory inputs forward. Unpredicted inputs arrive in circuits unprepared by alpha/beta, resulting in enhanced gamma and spiking. To test the predictive routing model and its role in consciousness, we collected data from intracranial recordings of macaque monkeys during passive presentation of auditory oddballs (e.g., AAAAB) before and after propofol-mediated loss of consciousness (LOC). In line with the predictive routing model, alpha/beta oscillations in the awake state served to inhibit the processing of predictable stimuli. Propofol-mediated LOC eliminated alpha/beta modulation by a predictable stimulus in sensory cortex and alpha/beta coherence between sensory and frontal areas. As a result, oddball stimuli evoked enhanced gamma power, late (> 200 ms from stimulus onset) period spiking, and superficial layer sinks in sensory cortex. Therefore, auditory cortex was in a disinhibited state during propofol-mediated LOC. However, despite these enhanced feedforward responses in auditory cortex, there was a loss of differential spiking to oddballs in higher order cortex. This may be a consequence of a loss of within-area and inter-area spike-field coupling in the alpha/beta and gamma frequency bands. These results provide strong constraints for current theories of consciousness. Significance statementNeurophysiology studies have found alpha/beta oscillations (8-30Hz), gamma oscillations (40-100Hz), and spiking activity during cognition. Alpha/beta power has an inverse relationship with gamma power/spiking. This inverse relationship suggests that gamma/spiking are under the inhibitory control of alpha/beta. The predictive routing model hypothesizes that alpha/beta oscillations selectively inhibit (and thereby control) cortical activity that is predictable. We tested whether this inhibitory control is a signature of consciousness. We used multi-area neurophysiology recordings in monkeys presented with tone sequences that varied in predictability. We recorded brain activity as the anesthetic propofol was administered to manipulate consciousness. Compared to conscious processing, propofol-mediated unconsciousness disrupted alpha/beta inhibitory control during predictive processing. This led to a disinhibition of gamma/spiking, consistent with the predictive routing model.

neuroscience↗

bioRxiv2023

TCCIA: A Comprehensive Resource for Exploring CircRNA in Cancer Immunotherapy

BackgroundImmunotherapies targeting immune checkpoints have gained increasing attention in cancer treatment, emphasizing the need for predictive biomarkers. Circular RNAs (circRNAs) have emerged as critical regulators of tumor immunity, particularly in the PD-1/PD-L1 pathway, and have shown potential in predicting immunotherapy efficacy. Yet, the detailed roles of circRNAs in cancer immunotherapy are not fully understood. While existing databases focus on either circRNA profiles or immunotherapy cohorts, there is currently no platform that enables the exploration of the intricate interplay between circRNAs and anti-tumor immunotherapy. A comprehensive resource combining circRNA profiles, immunotherapy responses, and clinical outcomes is essential to advance our understanding of circRNA-mediated tumor-immune interactions and to develop effective biomarkers. MethodsTo address these gaps, we constructed the Cancer CircRNA Immunome Atlas (TCCIA), the first database that combines circRNA profiles, immunotherapy response data, and clinical outcomes across multi-cancer types. The construction of TCCIA involved applying standardized preprocessing to the raw sequencing FASTQ files, characterizing circRNA profiles using an ensemble approach based on four established circRNA detection tools, analyzing tumor immunophenotypes, and compiling immunotherapy response data from diverse cohorts treated with immune-checkpoint blockades (ICBs). ResultsTCCIA encompasses over 4,000 clinical samples obtained from 25 cohorts treated with ICBs along with other treatment modalities. The database provides researchers and clinicians with a cloud-based platform that enables interactive exploration of circRNA data in the context of ICB. The platform offers a range of analytical tools, including browse of identified circRNAs, visualization of circRNA abundance and correlation, association analysis between circRNAs and clinical variables, assessment of the tumor immune microenvironment, exploration of tumor molecular signatures, evaluation of treatment response or prognosis, and identification of altered circRNAs in immunotherapy-sensitive and resistant tumors. To illustrate the utility of TCCIA, we showcase two examples, including circTMTC3 and circMGA, by employing analysis of large-scale melanoma and bladder cancer cohorts, which unveil distinct impacts and clinical implications of different circRNA expression in cancer immunotherapy. ConclusionsTCCIA represents a significant advancement over existing resources, providing a comprehensive platform to investigate the role of circRNAs in immuno-oncology. What is already known on this topicPrior knowledge indicated that circRNAs are involved in tumor immunity and have potential as predictive biomarkers for immunotherapy efficacy. However, there lacked a comprehensive database that integrated circRNA profiles and immunotherapy response data, necessitating this study. What this study addsThis study introduces TCCIA, a database that combines circRNA profiles, immunotherapy response data, and clinical outcomes. It provides a diverse collection of clinical samples and an interactive platform, enabling in-depth exploration of circRNAs in the context of checkpoint-blockade immunotherapy. How this study might affect research, practice or policyThe findings of this study offer valuable insights into the roles of circRNAs in tumor-immune interactions and provide a resource for researchers and clinicians in the field of immune-oncology. TCCIA has the potential to guide personalized immunotherapeutic strategies and contribute to future research, clinical practice, and policy decisions in checkpoint-blockade immunotherapy and biomarker development.

bioinformatics↗

bioRxiv2023

HDAC6/aggresome processing pathway importance for inflammasome formation is context dependent

The inflammasome is a large multiprotein complex that assembles in the cell cytoplasm in response to stress or pathogenic infection. Its primary function is to defend the cell and promote the secretion of pro-inflammatory cytokines, including IL-1{beta} and IL-18. It was shown that in immortalized bone marrow derived macrophages (iBMDMs) inflammasome assembly is dependent on the deacetylase HDAC6 and the aggresome processing pathway (APP), a cellular pathway involved in the disposal of misfolded proteins. Here we used primary BMDMs from mice in which HDAC6 is ablated or impaired and found that inflammasome activation was largely normal. We also used human peripheral blood mononuclear cells and monocytes cell lines expressing a synthetic protein blocking HDAC6-ubiquitin interaction and impairing the APP and found that inflammasome activation was moderately affected. Finally, we used a novel HDAC6 degrader and showed that inflammasome activation was partially impaired in human macrophage cell lines with depleted HDAC6. Our results therefore show that HDAC6 importance in inflammasome activation is context dependent.

immunology↗

bioRxiv2023

MultiPPIMI: a multimodal deep learning framework for predicting interactions between protein-protein interaction targets and modulators

Protein-protein interactions (PPIs) are essential for various biological processes and diseases. However, most existing computational methods for identifying PPI modulators require either target structure or reference modulators, which restricts their applicability to novel PPI targets. To address this challenge, we propose MultiPPIMI, a sequence-based deep learning framework that predicts the interaction between any given PPI target and modulator. MultiPPIMI integrates multimodal representations of PPI targets and modulators, and uses a bilinear attention network to capture inter-molecular interactions. Experimental results on our curated benchmark dataset show that MultiPPIMI achieves an average AUROC of 0.837 in three cold-start scenarios, and an AUROC of 0.994 in the random-split scenario. Furthermore, the case study show that MultiPPIMI can assist molecular simulations in screening inhibitors of Keap1/Nrf2 PPI interactions. We believe that the proposed method provides a promising way to screen PPI-targeted modulators.

bioinformatics↗

bioRxiv2023

Characterizing dysregulations via cell-cell communications in Alzheimer's brains using single-cell transcriptomes

Alzheimers disease (AD) is a devastating neurodegenerative disorder affecting 44 million people worldwide, leading to cognitive decline, memory loss, and significant impairment in daily functioning. The recent single-cell sequencing technology has revolutionized genetic and genomic resolution by enabling scientists to explore the diversity of gene expression patterns at the finest resolution. Here, we leveraged the large-scale and publicly available single-nucleus RNA sequencing (snRNA-seq) in the human prefrontal cortex (PFC) from 23 AD samples and 13 controls to investigate cell-to-cell communication (C2C) in healthy brains and their perturbations in AD. Specifically, we first performed broad communication pattern analyses and discovered the inter-mixing of cell types and signaling pathways in AD brains. Secondly, we performed cell-type- centric analysis and found that excitatory neurons in AD have significantly increased their communications to inhibitory neurons, while inhibitory neurons and other supporting cells globally decreased theirs to all cells. Then, we delved deeper with a signaling-centric view, showing that canonical signaling pathways CSF, TGF{beta}, and CX3C are significantly dysregulated in their signaling to the cell type microglia/PVM and WNT pathway is dysregulated in its signaling from endothelial to neuronal cells in AD. Finally, after extracting 23 known AD risk genes, our intracellular communication analysis revealed a strong connection of extracellular ligand genes APP, APOE, and PSEN1 to intracellular AD risk genes TREM2, ABCA1, and APP in the communication from astrocytes and microglia to neurons. In summary, with the novel advances in single-cell sequencing technologies, we show that cellular signaling is regulated in a cell-type- specific manner and that improper regulation of extracellular signaling genes is linked to intracellular risk genes, connecting signaling to genetic differences manifested in AD. Author SummaryAlzheimers is a devastating neurodegenerative disorder affecting 44 million people worldwide, leading to cognitive decline, memory loss, and significant impairment in daily functioning. The complex interplay of signaling genes suggests cells act in concert with other cells through cell-to-cell communication. Utilizing the recent advances in single-cell sequencing, we investigated dysregulated ligand-receptor gene pairs in the disease at the cell-type resolution. Specifically, our broad communication pattern analyses revealed the inter-mixing of cell types and signaling pathways in AD brains. Our cell-type-centric analysis found that excitatory neurons in AD have significantly increased their communications with inhibitory neurons, while inhibitory neurons and other supporting cells globally decreased theirs to all cells. With a signaling-centric view, we show that CSF, TGF{beta}, and CX3C pathways are significantly dysregulated in their signaling to the cell type microglia/PVM while the WNT pathway is dysregulated in its signaling from endothelial to neuronal cells in AD. Finally, our intracellular communication analysis revealed a strong connection of extracellular ligand genes APP, APOE, and PSEN1 to intracellular AD risk genes TREM2, ABCA1, and APP in the communication from astrocytes and microglia to neurons. In summary, performing a cell-to-cell communication analysis better explains the genetic differences manifested in Alzheimers.

bioinformatics↗

bioRxiv2023

LRRK2 G2019S promotes the development of colon cancer via modulating intestinal inflammation

LRRK2 G2019S is the most prevalent variant associated with Parkinsons disease (PD), found in 1-3% of sporadic and 4-8% of familial PD cases. Intriguingly, emerging clinical studies have suggested that LRRK2 G2019S carriers have an increased risk of cancers including colorectal cancer. However, the underlying mechanisms of the positive correlation between LRRK2-G2019S and colorectal cancer remain unknown. Using a mouse model of colitis-associated cancer (CAC) and LRRK2 G2019S knockin (KI) mice, here we report that LRRK2 G2019S promotes the pathogenesis of colon cancer as evidenced by increased tumor number and tumor size in LRRK2 G2019S KI mice. LRRK2 G2019S promoted intestinal epithelial cell proliferation and inflammation within the tumor microenvironment. Mechanistically, we found that LRRK2 G2019S KI mice are more susceptible to dextran sulfate sodium (DSS)-induced colitis. Suppressing the kinase activity of LRRK2 ameliorated the severity of colitis in both LRRK2 G2019S KI and WT mice. At the molecular level, our investigation unveiled that LRRK2 G2019S promotes the production of reactive oxygen species, triggers inflammasome activation, and induces cell necrosis in the gut epithelium in a mouse model of colitis. Collectively, our data provide direct evidence that gain-of-kinase activity in LRRK2 promotes colorectal tumorigenesis, implicating LRRK2 as a potential target in colon cancer patients with hyper LRRK2 kinase activity.

immunology↗