Biology subjects

Xiao, L.

Publications and source records attributed to Xiao, L..

At least 73 records · Page 4Linked to original sources

bioRxiv2023

CCT3 drives Sorafenib resistance by inhibiting TFRC-mediated iron uptake in HCC

Sorafenib is commonly utilized in the management of advanced hepatocellular carcinoma (HCC). However, its efficacy in extending patients survival is hindered by the development of drug resistance. By employing protein posttranslational modification (PTM) omics, including acetylome, phosphoproteome, and ubiquitinome, in conjunction with genome-wide CRISPR/Cas9 knockout library screening, we have successfully identified chaperonin containing TCP1 subunit 3 (CCT3) as a key factor contributing to Sorafenib resistance. Furthermore, we observed a reduction in the ubiquitination of CCT3 at lysine 21 (K21) subsequent to Sorafenib treatment. This study provides evidence that CCT3 hinders the recycling of transferrin receptor protein 1 (TFRC) by interacting with alpha-actinin-4 (ACTN4), which is influenced by K6-linked ubiquitination on K21. Depleting CCT3 increased the susceptibility of cells to Sorafenib-induced ferroptosis, while reintroducing CCT3 through transfection restored resistance to ferroptosis. Additionally, impairing ACTN4 or TFRC depletion compromised CCT3s ability to inhibit Sorafenib-induced ferroptosis. In summary, targeting CCT3 presents a potential strategy for overcoming Sorafenib resistance in HCC.

cancer biology↗

bioRxiv2023

Rapid dexamethasone treatment inhibits LPS-induced cytokine storm in mice

Severe infection-induced cytokine storm is an urgent medical syndrome with high mortality. To date, no therapy is available. This study shows that high concentrations of lipopolysaccharide (LPS) induce cytokine storm within 48h and thus kill most experimental mice. Rapid, but not late dexamethasone administration remarkably inhibits cytokine storm and rescues LPS-treated mice. Monocytes and macrophages are the major source of cytokine storm. In these cells, pro-inflammatory genes (i.e., Tnf, Il6 and Il1{beta}) have preassembled RNA polymerase II (RNA Pol II), but stay at the pause stage of transcriptional elongation in the absence of stimulation. LPS rapidly activates transcription of these "pre-loaded" genes within 2h. Administration of dexamethasone within this time window inhibits RNA Pol II ser2 binding to the core promoters of pro-inflammatory genes and thus reduces LPS-induced cytokine transcription. Therefore, rapid utilization of dexamethasone might be efficacious to prevent severe bacterium-induced cytokine storm in clinical practice.

molecular biology↗

bioRxiv2023

Cultivation of host-adapted Cryptosporidium parvum and Cryptosporidium hominis using enteroids for cryopreservation of isolates and transcriptomic studies of infection

Cryptosporidium hominis and Cryptosporidium parvum are major causes of severe diarrhea in humans. Comparative studies of them are hampered by the lack of effective cultivation and cryopreservation methods, especially for C. hominis. Here, we described adapted murine enteroids for the cultivation of one C. parvum IId subtype and nonhuman primate-adapted C. hominis Ib, Im, and In subtypes, which allowed the complete development of the pathogens, producing oocysts infectious to mice. Using the system, we developed a novel cryopreservation method for Cryptosporidium isolates. In comparative RNA-seq analyses of C. hominis cultures, the enteroid system generated significantly more transcriptomic responses of both pathogen and host genes than the conventional HCT-8 cell system. In particular, the infection was shown to upregulate PI3K-Akt, Wnt, Ras,TNF, NF-{kappa}B, IL-17, MAPK, and innate immunity signaling pathways and downregulate Wnt and Hippo signaling pathways, host cell metabolism, and parasites in enteroid cultures had significantly higher expression of genes involved in oocyst formation. Therefore, the new culture model provides a valuable tool for comparative studies of the biology of divergent Cryptosporidium species. IMPORTANCE The two dominant species for human cryptosporidiosis, Cryptosporidium hominis and Cryptosporidium parvum, differ significantly in host range and virulence. Up to date, biological studies of Cryptosporidium spp. are almost exclusively done with bovine-adapted IIa subtypes of C. parvum, which is the species with effective laboratory animal models and in vitro cultivation methods. Here, we describe modified procedures for the generation of murine enteroids for successful cultivation of both nonhuman primate-adapted C. hominis subtypes and a C. parvum IId subtype, producing oocysts infective to mice. In addition, we have developed a novel cryopreservation method using the system for long-term storage of Cryptosporidium isolates. RNA-seq analyses of C. hominis cultures indicate that the enteroid culture system generates host and pathogen transcriptomic responses similar to those in natural infection. This new development alleviates a technical bottleneck in cryptosporidiosis research, and provides an example for other difficult-to-culture pathogens of major public health importance.

microbiology↗

bioRxiv2023

Transcriptional profile of the rat cardiovascular system at single cell resolution

BackgroundDespite the critical role of the cardiovascular system, our understanding of its cellular and transcriptional diversity remains limited. We therefore sought to characterize the cellular composition, phenotypes, molecular pathways, and communication networks between cell types at the tissue and sub-tissue level across the cardiovascular system of the healthy Wistar rat, an important model in preclinical cardiovascular research. We obtained high quality tissue samples under controlled conditions that reveal a level of cellular detail so far inaccessible in human studies. Methods and ResultsWe performed single nucleus RNA-sequencing in 78 samples in 10 distinct regions including the four chambers of the heart, ventricular septum, sinoatrial node, atrioventricular node, aorta, pulmonary artery, and pulmonary veins (PV), which produced an aggregate map of 505,835 nuclei. We identified 26 distinct cell types and additional subtypes, including a number of rare cell types such as PV cardiomyocytes and non-myelinating Schwann cells (NMSCs), and unique groups of vascular smooth muscle cells (VSMCs), endothelial cells (ECs) and fibroblasts (FBs), which gave rise to a detailed cell type distribution across tissues. We demonstrated differences in the cellular composition across different cardiac regions and tissue-specific differences in transcription for each cell type, highlighting the molecular diversity and complex tissue architecture of the cardiovascular system. Specifically, we observed great transcriptional heterogeneities among ECs and FBs. Importantly, several cell subtypes had a unique regional localization such as a subtype of VSMCs enriched in the large vasculature. We found the cellular makeup of PV tissue is closer to heart tissue than to the large arteries. We further explored the ligand-receptor repertoire across cell clusters and tissues, and observed tissue-enriched cellular communication networks, including heightened Nppa - Npr1/2/3 signaling in the sinoatrial node. ConclusionsThrough a large single nucleus sequencing effort encompassing over 500,000 nuclei, we broadened our understanding of cellular transcription in the healthy cardiovascular system. The existence of tissue-restricted cellular phenotypes suggests regional regulation of cardiovascular physiology. The overall conservation in gene expression and molecular pathways across rat and human cell types, together with our detailed transcriptional characterization of each cell type, offers the potential to identify novel therapeutic targets and improve preclinical models of cardiovascular disease.

cell biology↗

bioRxiv2023

RNA Infrastructure Profiling Illuminates Transcriptome Structure in Crowded Spaces

RNAs can fold into compact three-dimensional structures, and most RNAs undergo protein interactions in the cell. These compact and occluded environments can block the ability of structure-probing agents to provide useful data about the folding and modification of the underlying RNA. The development of probes that can analyze structure in crowded settings, and differentiate the proximity of interactions, can shed new light on RNA biology. To this end, here we employ 2,-OH-reactive probes that are small enough to access folded RNA structure underlying many close molecular contacts within cells, providing considerably broader coverage for intracellular RNA structural analysis. We compare reverse transcriptase stops in RNA-Seq data from probes of small and standard size to assess RNA-protein proximity and evaluate solvent-exposed tunnels adjacent to RNA. The data are analyzed first with structurally characterized complexes (human 18S and 28S RNA), and then applied transcriptome-wide to polyadenylated transcripts in HEK293 cells. In our transcriptome profile, the smallest probe acetylimidazole (AcIm) yields 80% greater structural coverage than larger conventional reagent NAIN3, providing enhanced structural information in hundreds of transcripts. We further show that acetyl probes provide superior signals for identifying m6A modification sites in transcripts, and provide information regarding methylation sites that are inaccessible to a larger standard probe. RNA infrastructure profiling (RISP) enables enhanced analysis of transcriptome structure, modification, and interactions in living cells, especially in spatially crowded settings.

biochemistry↗

bioRxiv2023

Beta-catenin inhibition disrupts the homeostasis of osteogenic/adipogenic differentiation leading to the development of glucocorticoid-induced osteonecrosis of femoral head

Glucocorticoid-induced osteonecrosis of the femoral head (GONFH) is a common refractory joint disease characterized by bone damage and the collapse of femoral head structure. However, the exact pathological mechanisms of GONFH remain unknown. Here, we observed abnormal osteogenesis and adipogenesis associated with decreased {beta}-catenin in the necrotic femoral head of GONFH patients. In vivo and in vitro studies further revealed that glucocorticoid exposure disrupted osteogenic/adipogenic differentiation of bone marrow mesenchymal cells (BMSCs) by inhibiting {beta}-catenin signaling in glucocorticoid-induced GONFH rats. Col2+ lineage largely contributes to BMSCs, and was found an osteogenic commitment in the femoral head through 9 months of lineage trace. Specific deletion of {beta}-catenin in Col2+ cells shifted their commitment from osteoblasts to adipocytes, leading to a full spectrum of disease phenotype of GONFH in adult mice. Overall, we uncover that {beta}-catenin inhibition disrupting the homeostasis of osteogenic/adipogenic differentiation contributes to the development of GONFH, and identify an ideal genetic modified mouse model of GONFH.

pathology↗

bioRxiv2023

A muscle hypertrophy-derived myokine reprograms the stromal vascular fractions differentiation towards thermogenic adipocytes in subcutaneous adipose tissue

Skeletal muscle plays a significant role in both local and systemic energy metabolism; however, the cross-talk between skeletal muscle and adipose tissue remains largely unexplored. In this study, we identify the HIF2-Bambi-Thbs4 axis as a critical driver of muscle hypertrophy and metabolic improvement. Deletion of Bambi induces muscle hypertrophy and oxidative switching, thereby enhancing local and systemic metabolism under conditions of rodent chow and high-fat diets (HFD). Other than the metabolic regulation of skeletal muscle hypertrophy, we hypothesize that a portion of this improvement may be attributed to the metabolic reprogramming of the stromal vascular fraction (SVFs) of iWAT, promoting the development of beige adipocytes. Leveraging multi-omics approaches, we establish Thbs4 as a newly identified, muscle hypertrophy-derived myokine that serves as an essential regulator of this metabolic reprogramming. Thbs4 is upregulated in skeletal muscle during hypertrophy and aerobic exercise, localizes to the iWAT membrane, and facilitates the transformation of white adipocytes into beige adipocytes under conditions such as cold exposure, muscle hypertrophy, or aerobic exercise. Moreover, overexpression of Thbs4 elevates its plasma levels and leads to the transformation of white to beige adipocytes, therefore offering long-term protection against HFD-induced metabolic disorders. Conversely, Thbs4 knockout (Thbs4-KO) disrupts the metabolic reprogramming of SVFs and exacerbates metabolic syndromes induced by an HFD, mirroring the observed decline in Thbs4 levels in aged mice. Therefore, our findings underscore Thbs4s potential as both a long-term metabolic protective factor and a therapeutic target for the treatment of metabolic disorders. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=197 HEIGHT=200 SRC="FIGDIR/small/558627v1_ufig1.gif" ALT="Figure 1"> View larger version (63K): org.highwire.dtl.DTLVardef@1178e6org.highwire.dtl.DTLVardef@1184d4eorg.highwire.dtl.DTLVardef@7b592aorg.highwire.dtl.DTLVardef@1b0b03_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIBambi, a direct target gene of HIF2 in skeletal muscle, when deleted, triggers muscle hypertrophy and the transformation of white into beige adipocytes, improving systemic energy metabolism. C_LIO_LIThe metabolic reprogramming of stromal vascular fractions (SVFs) contributes to the observed improvements in energy metabolism and adipocyte hyperplasia. C_LIO_LIThbs4, a novel myokine produced in skeletal muscle during hypertrophy and aerobic exercise, plays a key role in the transformation of white into beige adipocytes. C_LIO_LIOverexpression of Thbs4 provides enduring protection against high-fat diet (HFD)-induced metabolic disorders, demonstrating its potential as a therapeutic target. C_LIO_LIThbs4 deletion abrogates the beneficial metabolic reprogramming of SVFs and exacerbates HFD-induced metabolic syndromes, further underlining its crucial role in metabolic regulation. C_LI

physiology↗

bioRxiv2023

The Role and Mechanism of TEAD4 in Preimplantation Embryonic Development in Mice and Cattle

Tead4, a critical transcription factor expressed during preimplantation development, is essential for the expression of trophectoderm-specific genes in mice. However, the functional mechanism of Tead4 in mouse preimplantation development and its conservation across mammals remain unclear. Here, we report that Tead4 is a crucial transcription factor necessary for blastocyst formation in mice. Disruption of Tead4 through base editing results in developmental arrest at the morula stage. Additionally, RNA-seq analysis reveals dysregulation of 670 genes in Tead4 knockout embryos. As anticipated, Tead4 knockout leads to a decrease in trophectoderm genes Cdx2 and Gata3. Intriguingly, we observed a reduction in Krt8, suggesting that Tead4 influences the integrity of the trophectoderm epithelium in mice. More importantly, we noted a dramatic decrease in nuclear Yap in outside cells for Tead4-deficient morula, indicating that Tead4 directly regulates Hippo signaling. In contrast, bovine embryos with TEAD4 depletion could still develop to blastocysts with normal expression of CDX2, GATA3, and SOX2, albeit with a decrease in total cell number and ICM cell number. In conclusion, we propose that Tead4 regulates mouse blastocyst formation via Krt8 and Yap, both of which are critical regulators of mouse preimplantation development.

developmental biology↗

bioRxiv2023

Distinct Neurodevelopmental Patterns and Intermediate Integration-Based Predictive Modeling in Autism Spectral Disorder

Autism Spectrum Disorder (ASD) is known to exhibit a more rapid expansion in brain structure during the early years of life compared to typically developing children (TD). This is of utmost importance in understanding atypical brain development and forecasting the onset of ASD. However, the precise age-related cortical changes (trajectories) that could pinpoint atypical brain development in ASD remain largely unknown. In this study, we characterize the distinct developmental patterns of cortical morphology in individuals with ASD, investigate the important neural biomarkers for ASD diagnostics, and propose a deep-learning workflow that combined graph convolutional networks with low-rank multi-model tensor fusion (LMFGCN) for ASD prediction. Our findings reveal that the constituents of gray matter volume (GV), cortical thickness (CT), and surface area (SA) exhibit separable developmental trajectories in ASD. Furthermore, we identify regional differences in CT and SA that underscore the separable brain developmental trajectories, both of which contribute to changes in GV. Our study also demonstrates that LMFGCN, an end-to-end deep-learning model with intermediate integrative approach, outperforms early and late integration methods and other state-of-the-art models in ASD classification. Overall, our results highlight the importance of distinguishing between cortical SA and CT for understanding ASD pathobiology, particularly during the early brain overgrowth period, and demonstrate the potential utility of LMFGCN in ASD classification.

neuroscience↗

bioRxiv2023

Defects in Mitochondrial Biogenesis Drive Mitochondrial Alterations in PINK1-deficient Human Dopamine Neurons

Mutations and loss of activity in the protein kinase PINK1 play a role in the pathogenesis of Parkinsons disease (PD). PINK1 regulates many aspects of mitochondrial quality control including mitochondrial autophagy (mitophagy), fission, fusion, transport, and biogenesis. Defects in mitophagy are though to play a predominant role in the loss of dopamine (DA) neurons in PD. Here we show that, although there are defects in mitophagy in human DA neurons lacking PINK1, mitochondrial deficits induced by the absence of PINK1 are primarily due to defects in mitochondrial biogenesis. Upregulation of PARIS and the subsequent down regulation of PGC-1 accounts for the mitochondrial biogenesis defects. CRISPR/Cas9 knockdown of PARIS completely restores the mitochondrial biogenesis defects and mitochondrial function without impacting the deficits in mitophagy due to the absence of PINK1. These results highlight the importance mitochondrial biogenesis in the pathogenesis of PD due to inactivation or loss of PINK1 in human DA neurons.

neuroscience↗

bioRxiv2023

Vacuolar H+-ATPase Determines Daughter Cell Fates through Asymmetric Segregation of the Nucleosome Remodeling and Deacetylase Complex

Asymmetric cell divisions (ACDs) generate two daughter cells with identical genetic information but distinct cell fates through epigenetic mechanisms. However, the process of partitioning different epigenetic information into daughter cells remains unclear. Here, we demonstrate that the nucleosome remodeling and deacetylase (NuRD) complex is asymmetrically segregated into the surviving daughter cell rather than the apoptotic one during ACDs in Caenorhabditis elegans. The absence of NuRD triggers apoptosis via the EGL-1-CED-9-CED-4-CED-3 pathway, while an ectopic gain of NuRD enables apoptotic daughter cells to survive. We identify the vacuolar H+-adenosine triphosphatase (V-ATPase) complex as a crucial regulator of NuRDs asymmetric segregation. V-ATPase interacts with NuRD and is asymmetrically segregated into the surviving daughter cell. Inhibition of V-ATPase disrupts cytosolic pH asymmetry and NuRD asymmetry. We suggest that asymmetric segregation of V-ATPase may cause distinct acidification levels in the two daughter cells, enabling asymmetric epigenetic inheritance that specifies their respective life-versus-death fates.

cell biology↗

bioRxiv2023

m6A mRNA Methylation in Brown Adipose Tissue Regulates Systemic Insulin Sensitivity via an Inter-Organ Prostaglandin Signaling Axis

Brown adipose tissue (BAT) has the capacity to regulate systemic metabolism through the secretion of signaling lipids. N6-methyladenosine (m6A) is the most prevalent and abundant post-transcriptional mRNA modification and has been reported to regulate BAT adipogenesis and energy expenditure. In this study, we demonstrate that the absence of m6A methyltransferase-like 14 (METTL14), modifies the BAT secretome to initiate inter-organ communication to improve systemic insulin sensitivity. Importantly, these phenotypes are independent of UCP1-mediated energy expenditure and thermogenesis. Using lipidomics, we identified prostaglandin E2 (PGE2) and prostaglandin F2a (PGF2a) as M14KO-BAT-secreted insulin sensitizers. Notably, circulatory PGE2 and PGF2a levels are inversely correlated with insulin sensitivity in humans. Furthermore, in vivo administration of PGE2 and PGF2a in high-fat diet-induced insulin-resistant obese mice recapitulates the phenotypes of METTL14 deficient animals. PGE2 or PGF2a improves insulin signaling by suppressing the expression of specific AKT phosphatases. Mechanistically, METTL14-mediated m6A installation promotes decay of transcripts encoding prostaglandin synthases and their regulators in human and mouse brown adipocytes in a YTHDF2/3-dependent manner. Taken together, these findings reveal a novel biological mechanism through which m6A-dependent regulation of BAT secretome regulates systemic insulin sensitivity in mice and humans. HighlightsO_LIMettl14KO-BAT improves systemic insulin sensitivity via inter-organ communication; C_LIO_LIPGE2 and PGF2a are BAT-secreted insulin sensitizers and browning inducers; C_LIO_LIPGE2 and PGF2a sensitize insulin responses through PGE2-EP-pAKT and PGF2a-FP-AKT axis; C_LIO_LIMETTL14-mediated m6A installation selectively destabilizes prostaglandin synthases and their regulator transcripts; C_LIO_LITargeting METTL14 in BAT has therapeutic potential to enhance systemic insulin sensitivity C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/542169v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@16b3393org.highwire.dtl.DTLVardef@1072ae3org.highwire.dtl.DTLVardef@190a6d7org.highwire.dtl.DTLVardef@1b98bce_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2023

Angiotensin II receptor inhibition ameliorates liver fibrosis and enhances hepatocellular carcinoma infiltration by effector T cells

Although viral hepatocellular carcinoma (HCC) is declining, non-viral HCC, which often is the end-stage of non-alcoholic or alcoholic steatohepatitis (NASH, ASH), is on an upward trajectory. Immune checkpoint inhibitors (ICI) that block the T cell inhibitory receptor PD-1 were approved for treatment of all HCC types. However, only a small portion of HCC patients show a robust and sustained response to PD-1 blockade, calling for improved understanding of factors that negatively impact response rate and duration and the discovery of new adjuvant treatments that enhance ICI responsiveness. Using a mouse model of NASH-driven HCC, we identified peritumoral fibrosis as a potential obstacle to T cell mediated tumor regression and postulated that anti-fibrotic medications may increase ICI responsiveness. We now show that the angiotensin II receptor inhibitor losartan, a commonly prescribed and safe antihypertensive drug, reduced liver and peritumoral fibrosis and substantially enhanced anti-PD-1 induced tumor regression. Although losartan did not potentiate T cell reinvigoration, it substantially enhanced HCC infiltration by effector CD8+ T cells compared to PD-1 blockade alone. The beneficial effects of losartan correlated with inhibition of TGF-{beta} receptor signaling, collagen deposition and depletion of immunosuppressive fibroblasts. SignificanceImmune checkpoint inhibitors are used in HCC treatment but overall response rates for single agent PD-1/PD-L1 blockers have remained stubbornly low. Using a mouse model of NASH-driven HCC, we show that co-treatment with the safe and inexpensive angiotensin II receptor inhibitor losartan substantially enhanced anti-PD-1 triggered HCC regression. Although losartan did not influence the reinvigoration of exhausted CD8+ T cells it considerably enhanced their intratumoral invasion, which we postulated to be compromised by peritumoral fibrosis. Indeed, the beneficial effect of losartan correlated with inhibition of TGF-{beta} signaling and collagen deposition, and depletion of immunosuppressive fibroblasts. Losartan should be evaluated for its adjuvant activity in HCC patients undergoing PD-1/PD-L1 blocking therapy.

cancer biology↗

bioRxiv2023

Comparison between Canine and Porcine Models of Chronic Deep Venous Thrombosis

Venous thromboembolism(VTE) refers to deep venous thrombosis(DVT) and pulmonary embolism(PE), which is a worldwide problem and has very high morbidity and mortality. The research of venous thrombosis involves pathogenesis, pathophysiology, and therapeutic attempt. Alternative experimental animal models have changed dramatically over the past 20 years, from small murine models to large ones. Larger animal models offer more options and are more consistent with human physiology. This article aims to induce chronic deep venous thrombosis in the left iliac vein in canine and porcine models and compare these two models. We think that feasible large animal models can better translate the results of therapeutic research into clinical application.

animal behavior and cognition↗

bioRxiv2023

Redox Regulation of m6A Methyltransferase METTL3 in Human β-cells Controls the Innate Immune Response in Type 1 Diabetes

Type 1 Diabetes (T1D) is characterized by autoimmune-mediated destruction of insulin-producing {beta}-cells. Several observations have renewed interest in the innate immune system as an initiator of the disease process against {beta}-cells. Here, we show that N6-Methyladenosine (m6A) is an adaptive {beta}-cell safeguard mechanism that accelerates mRNA decay of the 2-5-oligoadenylate synthetase (OAS) genes to control the antiviral innate immune response at T1D onset. m6A writer methyltransferase 3 (METTL3) levels increase drastically in human and mouse {beta}-cells at T1D onset but rapidly decline with disease progression. Treatment of human islets and EndoC-{beta}H1 cells with pro-inflammatory cytokines interleukin-1 {beta} and interferon mimicked the METTL3 upregulation seen at T1D onset. Furthermore, m6A-sequencing revealed the m6A hypermethylation of several key innate immune mediators including OAS1, OAS2, and OAS3 in human islets and EndoC-{beta}H1 cells challenged with cytokines. METTL3 silencing in human pseudoislets or EndoC-{beta}H1 cells enhanced OAS levels by increasing its mRNA stability upon cytokine challenge. Consistently, in vivo gene therapy, to prolong Mettl3 overexpression specifically in {beta}-cells, delayed diabetes progression in the non-obese diabetic (NOD) mouse model of T1D by limiting the upregulation of Oas pointing to potential therapeutic relevance. Mechanistically, the accumulation of reactive oxygen species blocked METTL3 upregulation in response to cytokines, while physiological levels of nitric oxide promoted its expression in human islets. Furthermore, for the first time to our knowledge, we show that the cysteines in position C276 and C326 in the zinc finger domain of the METTL3 protein are sensitive to S-nitrosylation (SNO) and are significant for the METTL3 mediated regulation of OAS mRNA stability in human {beta}-cells in response to cytokines. Collectively, we report that m6A regulates human and mouse {beta}-cells to control the innate immune response during the onset of T1D and propose targeting METTL3 to prevent {beta}-cell death in T1D.

molecular biology↗

bioRxiv2023

An ULK1/2-PXN mechanotransduction complex suppresses breast cancer cell migration

The remodeling and stiffening of the extracellular matrix (ECM) associated with breast cancers is a well-recognized modulator of disease progression. However, how changes in the mechanical properties of the ECM are converted into biochemical signals that direct tumor cell migration and metastasis remains poorly characterized. Here, we describe a new role for the autophagy-inducing serine/threonine kinases ULK1 and ULK2 in mechanotransduction. We demonstrate that ULK1/2 activity inhibits the assembly of actin stress fibers and focal adhesions (FAs), and as a consequence impedes cell contraction and migration. Mechanistically, we identify PXN/paxillin, a key component of the mechanotransducing machinery, as a direct binding partner and substrate of ULK1/2. ULK-mediated phosphorylation of PXN at S32 and S119 weakens homotypic interactions and liquid-liquid phase separation of PXN, impairing FA assembly, which in turn impedes the mechanotransduction of breast cancer cells. ULK1/2 and the well characterized PXN regulator, FAK/Src, have opposing functions on mechanotransduction and compete for phosphorylation of adjacent serine and tyrosine residues. Thus, our study reveals ULK1/2 as important regulators of PXN-dependent mechanotransduction. HighlightsO_LIULK1/2 interact with PXN and phosphorylate PXN at S32 and S119 in response to mechanical stimuli C_LIO_LIULK1/2-mediated phosphorylation of PXN regulates mechanotransduction and migration of breast cancer cells C_LIO_LIULK1/2 modulate the biomaterial properties of focal adhesions through PXN phosphorylation C_LIO_LIULK1/2 and FAK/Src act antagonistically in mechanotransduction through competitive phosphorylation of PXN C_LI

cell biology↗

bioRxiv2022

Artificial light at night advances reproductive phenology and reduces reproductive capacity of a wild plant

The rapid global expansion of artificial light at night (ALAN) has spurred growing interest in its ecological impact on plant life. However, the effects of low-intensity ALAN on plants in their natural habitats remain largely unexplored, particularly concerning the influence of morphological and phenological responses on the overall fitness of these plants. We conducted a field experiment using the annual herbaceous plant Elsholtzia densa as a model species to assess the effects of ALAN on plant morphology, reproductive phenology, and reproductive capacity. The results indicate that ALAN increased the specific leaf area and elongated the top inflorescences, but it resulted in a reduction of secondary branches and a decrease in the proportion of individuals with undeveloped top inflorescences. Additionally, ALAN induced a shift in biomass allocation toward the aboveground parts of plants. It also accelerated the onset of budding, blooming, fruiting, and seed maturity by 3.4 to 6.2 days and caused a decrease in the number of fruity inflorescences. This study suggests that ALAN can significantly affect plant morphology, reproductive timing, and potentially the fitness of plants. While ALAN induces potentially adaptive changes in leaf area and biomass allocation, it may also disrupt plant-pollinator interactions and negatively impact plant reproductive capacity.

ecology↗

bioRxiv2022

From whole genome to probiotic candidates: a study of potential Lactobacillus strain selection for vaginitis treatment

Vaginitis is a syndrome characterized by not only the invasion of pathogens, but also the lack of Lactobacillus. Lactobacillus supplementation emerged as an innovative therapy for vaginitis which targeted the vaginal microbiota in recent years. However, limited live biotherapeutic products were explicitly marketed for this. The aim of our study is to characterize the potential Lactobacillus candidates for enhancing the treatment of vaginitis. Initially, 98 Lactobacillus isolates with whole genome were selected into the candidate pool. The genomic pathways involved in the biosynthesis of probiotic metabolites, adhering ability and acid/bile resistance, as well as sequences of antibiotic resistance genes, plasmids, transposons, viruses, and prophages were annotated. A scoring model was then established based on genomic analysis for ranking the performance of the strains, and the top-performing ones were applied to in vitro tests for sub-screening. As a result, two candidates were selected, and their probiotic abilities were verified with three reference strains. L. crispatus LG55-27 and L. gasseri TM13-16 presented outstanding ability to produce D-lactate and adhere to human vaginal epithelial cells. They also showed higher antimicrobial activity against Gardnerella vaginalis, Escherichia coli, Candida albicans, Staphylococcus aureus and Pseudomonas aeruginosa than control ones. Their acid/bile-resistant ability suggested the potential of oral supplementation. Strain LG55-27 and TM13-16 also display improved effects on pH changes, and the production of inflammation cytokines in BV model rats. This study provided a probiotic dosage recommendation for vaginitis treatment by demonstrating an effective probiotic screening pipeline based on genome sequences, in vitro tests and in vivo BV model experiment.

microbiology↗