Biology subjects

Liu, H.

Publications and source records attributed to Liu, H..

At least 559 records · Page 31Linked to original sources

bioRxiv2023

Glutamatergic neurons in the infralimbic cortex for motivational response of pain relief induced by electroacupuncture

Peripheral neuromodulation by electroacupuncture (EA) is a promising tool for both experimental and clinical applications. However, whether EA signals reflect a multidimensional composite and evoke affective and motivational processes remains largely elusive. Here, we demonstrated that EA at ST.36 acupuncture point considerably attenuated pain hypersensitivity at 24h and 48h postincision. In conditioned place preference (CPP) model, one chamber becomes associated with EA through three-day repeated pairings, whereas the other chamber is associated with no EA stimulation. EA stimulation resulted in strong preference for the chamber paired with EA in incisional injury (INP) rats. In contrast, EA at non-acupuncture points in INP rats did not relief pain and produce CPP. Notably, EA with the context in sham-operated animals did not induce CPP. Next, we identified neurons activation in brain associated with affective and motivational aspects of pain after EA stimulation using immediate early gene c-Fos expression in SNI rats. EA stimulation increased c-Fos positive neurons in the IL, but not cingulate (Cg1) and prelimbic (PL) subregion of the mPFC. Sham EA did not increase c-Fos expression in the IL in spared nerve injury (SNI) rats. Using reversible inactivation of IL in rats, inactivation of the IL significantly abolished CPP of pain relief induced by EA. Optogenetic activation of IL glutamatergic neurons mimicked EA-induced analgesia and CPP behaviors, and inhibition of glutamatergic neurons in the IL reversed the effects of EA. The study directly demonstrates a novel and important role for glutamatergic neurons in the infralimbic cortex in acupuncture-induced motivational response of pain relief and provides a new perspective for investigating acupuncture analgesia.

neuroscience↗

bioRxiv2023

Dominant Role of Stochastic Processes in Soil Fungal Communities in Pioneer Forests at a Regional Scale

Soil fungal community assembly is driven by deterministic and stochastic processes. However, the contribution of these mechanisms to structure the composition of fungal communities of forest soils at the regional scale is poorly known. Here, we investigate the relative importance of deterministic and stochastic processes on fungal community composition by rDNA ITS metabarcoding in a Populus davidiana pioneer forests along spatial-temporal gradients. We also assessed the impact of elevation and seasonality. The soil fungal richness of P. davidiana pioneer forests was significantly affected by elevation and less affected by season. Similarly, the variation in the fungal community composition according to the elevation was greater than the effect of seasonality. The fungal community composition showed a significant distance-decay relationship. Variation partitioning analysis showed that plant variables explained the soil fungal community variation. Through null model analysis, we found that stochastic processes were dominant in the soil fungal community assembly. However, the relative importance of ecological processes, including dispersal, selection, and drift, was not consistent across the four soil fungal community assemblies. In addition, the undominated fraction (including weak selection, weak dispersal, diversification and drift) had a high relative contribution to the soil fungal community assembly process in the P. davidiana pioneer forest. In summary, our results demonstrated that plant variables and the undominated fraction dominate the deterministic and stochastic processes driving soil fungal community assemblies in a P. davidiana pioneer forest at the regional scale, which provides new perspectives for the regional scale studies of soil fungi. IMPORTANCEElevation and seasonality are important factors driving the composition of soil microbiota. Due to the tight interactions of soil fungi with their host trees in forest ecosystems, the spatial variation of soil fungal community is often linked to the variation in the composition of dominant tree species. We compared the responses of soil fungal communities to seasonal and spatial changes at four levels in a temperate poplar forest dominated by a single tree species under elevation changes. Elevation had a higher impact than seasonality on the soil fungal beta diversity. Even when the shift in dominant tree species was limited, vegetation factors still impact soil fungal community variations. The dominant role of homogeneous selection and drift in fungal community assemblies, except for ectomycorrhizal fungi, was further discovered.

microbiology↗

bioRxiv2023

An explainable artificial intelligence-based typification of chronic inflammatory responses enhances glioma prognosis

Glioma is one of the most aggressive solid brain tumors with a poor prognosis. A chronic tumor inflammatory microenvironment drives glioma promotion and progression. The neutrophil-to-lymphocyte ratio and other clinicopathological variables usually serve as prognostic glioma markers. However, they are not ubiquitous prognostic markers for glioma as they fail to reveal the intricacy between the glioma-specific tumor inflammatory microenvironment and the systemic inflammatory responses, especially those chronic inflammatory responses, which vary among individuals fabricating diverse prognostic outcomes. Here, we introduced an explainable artificial intelligence model to typify chronic inflammatory responses as prognostic markers for glioma using 694-patients data from The Cancer Genome Atlas. We characterized the glioma-specific personalized inflammatory mediators using multi-layered regulators such as transcriptional networks, cellular infiltration markers, and cellular senescence markers, which identified five unique chronic inflammatory responses (p-value<0.0001). We defined its prognostic significance using overall survival analyses. The chronic inflammatory responses were positively correlated with poor overall survival in glioma. The patients with higher chronic inflammatory responses showed significantly shorter overall survival than those with lower chronic inflammatory responses. Interestingly, optimizing those chronic inflammatory responses improved the overall survival of glioma patients. We identified the effector genes within the personalized inflammatory mediators networks, indicating them as the targets for optimizing individualized chronic inflammatory response profiles through co-drug intervention. SignificanceExplainable artificial intelligence-based typification of chronic inflammatory responses accelerates glioma prognosis and supports co-drug discovery to modulate inflammatory responses alongside cancer therapy, suggested by 694-glioma patients data analysis.

systems biology↗

bioRxiv2023

StereoCell enables high accuracy single cell segmentation for spatial transcriptomic dataset

BackgroundOwing to recent advances in resolution and field-of-view, spatially resolved transcriptomics sequencing, such as Stereo-seq, has emerged as a cutting-edge technology for the interpretation of large tissues at the single-cell level. To generate accurate single-cell spatial gene expression profiles from high-resolution spatial omics data, a powerful computational tool is required. FindingsWe present CellBin, an image-facilitated one-stop pipeline for high-resolution and large field-of-view spatial transcriptomic data of Stereo-seq. CellBin provides a comprehensive and systematic platform for generating high-confidence single-cell spatial gene expression profiles, which specifically includes image stitching, image registration, tissue segmentation, nuclei segmentation and molecule labeling. CellBin is user-friendly and does not require a specific level of omics and image analysis expertise. ConclusionsDuring image stitching and molecule labeling, CellBin delivers better-performing algorithms to reduce stitching error and time, in addition to improving the signal-to-noise ratio of single-cell gene expression data, in comparison with existing methods. Additionally, CellBin has been shown to obtain highly accurate single-cell spatial data using mouse brain tissue, which facilitated clustering and annotation.

bioinformatics↗

bioRxiv2023

Brain Organoid Computing for Artificial Intelligence

Brain-inspired hardware emulates the structure and working principles of a biological brain and may address the hardware bottleneck for fast-growing artificial intelligence (AI). Current brain-inspired silicon chips are promising but still limit their power to fully mimic brain function for AI computing. Here, we develop Brainoware, living AI hardware that harnesses the computation power of 3D biological neural networks in a brain organoid. Brain-like 3D in vitro cultures compute by receiving and sending information via a multielectrode array. Applying spatiotemporal electrical stimulation, this approach not only exhibits nonlinear dynamics and fading memory properties but also learns from training data. Further experiments demonstrate real-world applications in solving non-linear equations. This approach may provide new insights into AI hardware.

bioengineering↗

bioRxiv2023

ClockBase: a comprehensive platform for biological age profiling in human and mouse

Decades of publicly available molecular studies have generated millions of samples testing diverse interventions, yet these datasets were rarely analyzed for their effects on aging. Aging clocks now enable biological age estimation and life outcome prediction from molecular data, creating an opportunity to systematically mine this untapped resource. We developed ClockBase Agent, a publicly accessible platform that reanalyzes millions of human and mouse methylation and RNA-seq samples by integrating them with over 40 aging clock predictions. ClockBase Agent employs specialized AI agents that autonomously generate aging-focused hypotheses, evaluate intervention effects on biological age, conduct literature reviews, and produce scientific reports across all datasets. Reanalyzing 43,602 intervention-control comparisons through multiple aging biomarkers revealed thousands of age-modifying effects missed by original investigators, including over 500 interventions that significantly reduce biological age (e.g., ouabain, KMO inhibitor, fenofibrate, and NF1 knockout). Large-scale systematic analysis reveals fundamental patterns: significantly more interventions accelerate rather than decelerate aging, disease states predominantly accelerate biological age, and loss-of-function genetic approaches systematically outperform gain-of-function strategies in decelerating aging. As validation, we show that identified interventions converge on canonical longevity pathways and with strong concordance to independent lifespan databases. We further experimentally validated ouabain, a top-scoring AI-identified candidate, demonstrating reduced frailty progression, decreased neuroinflammation, and improved cardiac function in aged mice. ClockBase Agent establishes a paradigm where specialized AI agents systematically reanalyze all prior research to identify age-modifying interventions autonomously, transforming how we extract biological insights from existing data to advance human healthspan and longevity.

bioinformatics↗

bioRxiv2023

Pan-cancer genetic analysis of disulfidptosis-related gene set

BackgroundA recent study has identified a novel programmed cell death pathway, termed disulfidoptosis, which is based on disulfide proteins. This discovery provides new insight into the mechanisms of cell death and may have implications for therapeutic strategies targeting cell death pathways. This study aimed to evaluate the pan-cancer genomics and clinical association of disulfidptosis and disulfidptosis-related cell death genes, including SLC7A11, NADPH, INF2, CD2AP, PDLIM1, ACTN4, MYH9, MYH10, IQGAP1, FLNA, FLNB, TLN1, MYL6, ACTB, DSTN, and CAPZB. MethodsUsing multi-omics profiling data, this study provides a comprehensive and systematic characterization of disulfidptosis genes across more than 9000 samples of over 30 types of cancer. ResultsFLNA and FLNB were the two most frequently mutated disulfidptosis cell death genes in cancer. UCEC and SKCM were the two cancer types that have the highest mutation rates while the mutation of ACTN4 was associated with worse survival of CESC and ESCA. Breast cancer was potentially affected by disulfidptosis because its subtypes are different in disulfidptosis gene expression. Similarly, KIRC might also be associated with disulfidptosis.). Additionally, the association of disulfidptosis-related cell death genes with survival was analyzed, with MESO and LGG as the top cancer types with survival associated with disulfidptosis cell death genes. The correlation between CNV and survival across multiple cancer types found that UCEC, KIRP, LGG, and KIRC were the top cancer types where the CNV level was associated with survival. There was a negative correlation between expression and methylation for most of the genes and there was only a slight correlation between methylation levels and survival of cancer in LGG. About half of the disulfidptosis-related cell death proteins were associated with the activation of EMT. Disulfidptosis genes were correlated to immune cell infiltration levels in cancers. Multiple compounds were identified as potential drugs that might be affected by disulfidptosis-related cell death for future study. ConclusionDisulfidptosis cell death genes are potentially involved in many cancer types and can be developed as candidates for cancer diagnosis, prognosis, and therapeutic biomarkers.

bioinformatics↗

bioRxiv2023

Excessive apoptosis of naïve T cells resulting hyperactivation as a cause of mammalian aging

In mammals, the most remarkable T cell variations with aging are the shrinking of naive T cell pool and enlargement of memory T cell pool, which are partially caused by thymic involution. However, it remains an enigma whether these T-cell-related changes are consequences or causes of mammalian aging. In this study, we find that the T-cell specific Rip1 KO mice present similar age-related T cell changes and exhibit signs of accelerated aging, including inflammation, multiple age-related diseases and a shorter lifespan. Mechanistically, T cells lacking RIP1 displayed excessive apoptosis, leading to T cell compensatory proliferation, hyperactivation, increased inflammation, and ultimately premature death. Consistent with this, blocking apoptosis by co-deletion of Fadd in Rip1 deficient T cells significantly recovered the lymphopenia and imbalance between naive and memory T cell, substantially restored ageing-related phenotypes, and prolonged life span in T-cell specific Rip1 KO mice. These results suggest that changes in T cells play a causal role in mammalian aging. Therefore, replenishing or blocking apoptosis of naive T cells could offer new therapeutic approaches for aging and age-related diseases.

immunology↗

bioRxiv2023

2019-20 H1N1 clade A5a.1 viruses have better in vitro replication compared with the co-circulating A5a.2 clade

Surveillance for emerging human influenza virus clades is important for identifying changes in viral fitness and assessing antigenic similarity to vaccine strains. While fitness and antigenic structure are both important aspects of virus success, they are distinct characteristics and do not always change in a complementary manner. The 2019-20 Northern Hemisphere influenza season saw the emergence of two H1N1 clades: A5a.1 and A5a.2. While several studies indicated that A5a.2 showed similar or even increased antigenic drift compared with A5a.1, the A5a.1 clade was still the predominant circulating clade that season. Clinical isolates of representative viruses from these clades were collected in Baltimore, Maryland during the 2019-20 season and multiple assays were performed to compare both antigenic drift and viral fitness between clades. Neutralization assays performed on serum from healthcare workers pre- and post-vaccination during the 2019-20 season show a comparable drop in neutralizing titers against both A5a.1 and A5a.2 viruses compared with the vaccine strain, indicating that A5a.1 did not have antigenic advantages over A5a.2 that would explain its predominance in this population. Plaque assays were performed to investigate fitness differences, and the A5a.2 virus produced significantly smaller plaques compared with viruses from A5a.1 or the parental A5a clade. To assess viral replication, low MOI growth curves were performed on both MDCK-SIAT and primary differentiated human nasal epithelial cell cultures. In both cell cultures, A5a.2 yielded significantly reduced viral titers at multiple timepoints post-infection compared with A5a.1 or A5a. Receptor binding was then investigated through glycan array experiments which showed a reduction in receptor binding diversity for A5a.2, with fewer glycans bound and a higher percentage of total binding attributable to the top three highest bound glycans. Together these data indicate that the A5a.2 clade had a reduction in viral fitness, including reductions in receptor binding, that may have contributed to the limited prevalence observed after emergence.

microbiology↗

bioRxiv2023

The histone demethylase KDM5C controls female bone mass by promoting energy metabolism in osteoclasts

Women experience osteoporosis at higher rates than men. Aside from hormones, the mechanisms driving sex-dependent bone mass regulation are not well-understood. Here, we demonstrate that the X-linked H3K4me2/3 demethylase KDM5C regulates sex-specific bone mass. Loss of KDM5C in hematopoietic stem cells or bone marrow monocytes (BMM) increases bone mass in female but not male mice. Mechanistically, loss of KDM5C impairs the bioenergetic metabolism resulting in impaired osteoclastogenesis. Treatment with the KDM5 inhibitor reduces osteoclastogenesis and energy metabolism of both female mice and human monocytes. Our report details a novel sex-dependent mechanism for bone homeostasis, connecting epigenetic regulation to osteoclast metabolism, and positions KDM5C as a target for future treatment of osteoporosis in women. One-Sentence SummaryKDM5C, an X-linked epigenetic regulator, controls female bone homeostasis by promoting energy metabolism in osteoclasts.

cell biology↗

bioRxiv2023

Candida albicans stimulates the formation of a multi-receptor complex that mediates epithelial cell invasion during oropharyngeal infection

Fungal invasion of the oral epithelium is central to the pathogenesis of oropharyngeal candidiasis (OPC). Candida albicans invades the oral epithelium by receptor-induced endocytosis but this process is incompletely understood. We found that C. albicans infection of oral epithelial cells induces c-Met to form a multi-protein complex with E-cadherin and the epidermal growth factor receptor (EGFR). E-cadherin is necessary for C. albicans to activate both c-Met and EGFR and to induce the endocytosis of C. albicans. Proteomics analysis revealed that c-Met interacts with C. albicans Hyr1, Als3 and Ssa1. Both Hyr1 and Als3 were required for C. albicans stimulation of c-Met and EGFR in oral epithelial cells in vitro and for full virulence during OPC in mice. Treating mice with small molecule inhibitors of c-Met and EGFR ameliorated OPC, demonstrating the potential therapeutic efficacy of blocking these host receptors for C. albicans. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=161 HEIGHT=200 SRC="FIGDIR/small/529756v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@1448372org.highwire.dtl.DTLVardef@111b411org.highwire.dtl.DTLVardef@144f3b8org.highwire.dtl.DTLVardef@1dcf548_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIc-Met is an oral epithelial cell receptor for Candida albicans C_LIO_LIC. albicans infection causes c-Met and the epidermal growth factor receptor (EGFR) to form a complex with E-cadherin, which is required for c-Met and EGFR function C_LIO_LIC. albicans Hyr1 and Als3 interact with c-Met and EGFR, inducing oral epithelial cell endocytosis and virulence during oropharyngeal candidiasis C_LIO_LIDual blockade of c-Met and EGFR ameliorates oropharyngeal candidiasis C_LI

microbiology↗

bioRxiv2023

High-throughput screening of functional neo-antigens and their specific TCRs via the Jurkat reporter system combine with droplet microfluidics

T-cell receptor (TCR)-engineered T cells can precisely recognize a broad repertoire of targets derived from both intracellular and surface proteins of tumor cells. TCR-T adoptive cell therapy has shown safety and promising efficacy in solid tumor immunotherapy. However, antigen-specific functional TCR screening is time-consuming and expensive, which limits its application clinically. Here, we developed a novel integrated antigen-TCR screening platform based on droplet microfluidics technology, enabling high-throughput peptide-major histocompatibility complex (pMHC) library-to-TCR library screening with high sensitivity and low background signal. We introduced DNA barcoding technology to label peptide antigen candidate-loaded antigen-presenting cells (APCs) and Jurkat reporter cells to check the specificity of pMHC-TCR candidates. Coupled with the next-generation sequencing pipeline, interpretation of the DNA barcodes and the gene expression level of the Jurkat T-cell activation pathway provided a clear peptide-MHC-TCR recognition relationship. Our proof-of-principle study demonstrates that the platform could achieve unbiased pMHC-TCR library-on-library screening, which is expected to be used in the cross-reactivity and off-target testing of candidate pMHC-TCR libraries in clinical applications.

bioengineering↗

bioRxiv2023

Complementary effects of above- and belowground biodiversity on ecosystem functions across global grasslands

Grasslands are integral to maintaining biodiversity and key ecosystem services under climate change. Plant and soil biodiversity, and their interactions, support the provision of multiple ecosystem functions (multifunctionality). However, whether plant and soil biodiversity explain unique, or shared, contributions to supporting multifunctionality across global grasslands remains virtually unknown. Here, we combine results from a global survey of 101 grasslands with a novel microcosm study, controlling for both plant and soil microbial diversity to identify their individual and interactive contribution to support multifunctionality under aridity and experimental drought. We found that, plant and soil microbial diversity independently predict a unique portion of variation in above- and belowground functioning, suggesting both types of biodiversity complement each other. Interactions between plant and soil microbial diversity regulated primary productivity, nutrient storage, and plant productivity. Our findings were also context dependent, since soil fungal diversity was strongly associated to multifunctionality in less arid regions, while plant diversity was strongly linked to multifunctionality in more arid regions. Our results highlight the need to conserve both above- and belowground diversity to sustain grassland multifunctionality in a drier world and indicate climate change may shift the relative contribution of plant and soil biodiversity to multifunctionality across global grasslands.

ecology↗

bioRxiv2023

Omics Analysis Unveils the Pathway Involved in the Purple Coloration in Tomato Seedling and Fruits

The purple tomato variety Indigo Rose(InR) is favored due to its bright appearance and abundant anthocyanins. SlHY5 is associated with anthocyanin biosynthesis in Indigo Rose plants. However, residual anthocyanins still present in Slhy5 seedlings and fruit peel indicated there was an anthocyanin induction pathway that is independent of HY5 in plants. The molecular mechanism of color formation in Indigo Rose and Slhy5 mutants is unclear. In this study, we performed omics analysis to clarify the regulatory network underlying coloration in seedling and fruit peel of Indigo Rose and Slhy5 mutant. Results showed that the total amount of anthocyanins in both seedling and fruit of InR were significantly higher than those in Slhy5 mutant and most genes associated with anthocyanin biosynthesis exhibited higher expression levels in InR, suggesting that SlHY5 play pivotal roles in flavonoid biosynthesis both in tomato seedlings and fruit. Yeast two-hybrid (Y2H) results revealed that SlBBX24 physically interacts with SlAN2-like and SlAN2, while SlWRKY44 could interact with SlAN11 protein. Unexpectedly, both SlPIF1 and SlPIF3 were found to interact with SlBBX24, SlAN1 and SlJAF13 by yeast two-hybrid assay. Suppression of SlBBX24 by virus-induced gene silencing (VIGS) retarded the purple coloration of the fruit peel, indicating an important role of SlBBX24 in the regulation of anthocyanin accumulation. These results deepen the understanding of purple color formation in tomato seedling and fruits in an HY5-dependent or independent manner via excavating the genes involved in anthocyanin biosynthesis based on omics analysis.

molecular biology↗

bioRxiv2023

An orally bioavailable 4-phenoxy-quinoline compound as a potent AURKB relocation blocker for cancer treatment

We investigated a novel 4-phenoxy-quinoline-based scaffold that mislocalizes the essential mitotic kinase, AURKB. Here, we evaluated the impact of halogen substitutions (F, Cl, Br, I) on this scaffold with respect to various drug parameters. Br-substituted LXY18 was found to be a potent and orally bioavailable disruptor of cell division, at sub-nanomolar concentrations. LXY18 prevents cytokinesis by blocking AURKB relocalization in mitosis and exhibits broad-spectrum antimitotic activity in vitro. With a favorable PK profile, it shows widespread tissue distribution including the blood-brain barrier penetrance and effective accumulation in tumor tissues. More importantly, it markedly suppresses tumor growth. The novel mode of action of LXY18 may eliminate some drawbacks of direct catalytic inhibition of AURKs. Successful development of LXY18 as a clinical candidate for cancer treatment could enable a new, less toxic means of antimitotic attack that avoids drug resistance mechanisms.

cancer biology↗

bioRxiv2023

New climatically specialized lineages of Batrachochytrium dendrobatidis and their sub-lethal effects on amphibians establish the Asiatic origins of the pathogen

Chytridiomycosis, a highly significant global wildlife disease, has caused unprecedented amphibian population declines and species extinctions worldwide. In contrast, mass die-offs due to chytridiomycosis have not been observed in Asia, which is thought to be the ancestral region of origin and a hyper-diversity hotspot of the known causal pathogens, Batrachochytrium dendrobtidis (Bd) and B. salamndrivorans (Bsal). It has been hypothesized that Asian amphibians may have evolved immunity to clinical Batrachochytrium infection. However, limited knowledge of endemic lineages, evolutionary history, and climate-related infection patterns limits our ability to explore this hypothesis. Here, we investigated the genetic diversity and infection patterns of the frog-infecting species, Bd, in Chinas poorly-explored Guangxi region. We used the internal transcribed spacer (ITS) marker and the nested PCR method to survey prevalence and haplotype diversity of Bd across 17 forest sites. A generalized linear model was used to evaluate associations between numerous variables and Bd prevalence within native amphibians. Our results identified seven new haplotypes, four of which are closely related to the early-emerging BdASIA-1 lineage recovered from South Korea. We also identified a unique Asian haplotype, close to the BdASIA-3 lineage, as the most prevalent (64.6% of Bd-infected adult individuals) in 11 out of 15 infected species. This haplotype was also detected in a salamander individual, which exhibited non-lethal skin lesions on the abdomen. The infection of Bd within amphibians was found to be positively associated with temperature and elevation. Our findings suggest that there is significant undiscovered genetic diversity of Asian Bd lineages in this region. Longer-term studies are required to further investigate Bd diversity, prevalence, seasonality and impact on native species and populations in Southern China and across the region of origin in Asia. Author SummaryChytridiomycosis is a disease which is responsible for the sharp decline of amphibian populations and species extinctions around the world. Surprisingly, it has not yet been well-studied in Asia, the region where the two causal pathogens of the disease, Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal) originated. In order to better understand the lack of mass die-offs in Asia, we recently conducted a study in south Chinas Guangxi region to investigate the genetic diversity and infection patterns of Bd. Through the use of internal transcribed spacer (ITS) markers and nested PCR, we discovered seven new types of Bd, four of which were closely related to the early-emerging BdASIA-1 lineage from South Korea. The highest prevalence of Bd infection was observed in 11 species of amphibians, including a salamander which had non-lethal skin lesions. It was also noted that infection of Bd in amphibians was associated with temperature and elevation. This study has provided important information on Bd diversity and prevalence in the region, and further research is needed to explore Asia as the putative region of origin for this disease.

evolutionary biology↗

bioRxiv2023

Osteoblast-intrinsic defect in glucose metabolism impairs bone formation in type II diabetic mice

Skeletal fragility is associated with type 2 diabetes mellitus (T2D), but the underlying mechanism is not well understood. Here, in a mouse model for youth-onset T2D, we show that both trabecular and cortical bone mass are reduced due to diminished osteoblast activity. Stable isotope tracing in vivo with 13C-glucose demonstrates that both glycolysis and glucose fueling of the TCA cycle are impaired in diabetic bones. Similarly, Seahorse assays show suppression of both glycolysis and oxidative phosphorylation by diabetes in bone marrow mesenchymal cells as a whole, whereas single-cell RNA sequencing reveals distinct modes of metabolic dysregulation among the subpopulations. Metformin not only promotes glycolysis and osteoblast differentiation in vitro, but also improves bone mass in diabetic mice. Finally, targeted overexpression of Hif1a or Pfkfb3 in osteoblasts of T2D mice averts bone loss. The study identifies osteoblast-intrinsic defects in glucose metabolism as an underlying cause of diabetic osteopenia, which may be targeted therapeutically.

physiology↗

bioRxiv2023

SUMO protease FUG1, histone reader AL3 and the PRC1 Complex are integral to repeat-expansion induced epigenetic silencing in Arabidopsis thaliana

Epigenetic gene silencing induced by expanded repeats can cause diverse phenotypes ranging from severe growth defects in plants to genetic diseases such as Friedreichs ataxia in humans1. The molecular mechanisms underlying repeat expansion-induced epigenetic silencing remain largely unknown2,3. Using a plant model, we have previously shown that expanded repeats can induce smallRNAs which in turn can lead to epigenetic silencing through the RNA-dependent DNA methylation pathway4,5. Here, using a genetic suppressor screen, we confirm a key role for the RdDM pathway and identify novel components required for epigenetic silencing caused by expanded repeats. We show that FOURTH ULP LIKE GENE CLASS 1 (FUG1) - a SUMO protease, ALFIN-LIKE 3 - a histone reader and LIKE HETEROCHROMATIN 1 (LHP1) - a component of the PRC1 complex are required for repeat expansion-induced epigenetic silencing. Loss of any of these components suppress repeat expansion-associated phenotypes. SUMO protease FUG1 physically interacts with AL3 and perturbing its potential SUMOylation site disrupts its nuclear localisation. AL3 physically interacts with LHP1 of the PRC1 complex and the FUG1-AL3-LHP1 module is essential to confer repeat expansion-associated epigenetic silencing. Our findings highlight the importance post-translational modifiers and histone readers in epigenetic silencing caused by repeat expansions.

genetics↗