Biology subjects

Guo, H.

Publications and source records attributed to Guo, H..

At least 127 records · Page 7Linked to original sources

bioRxiv2022

Triterpenoid production with a minimally engineered Saccharomyces cerevisiae chassis

Triterpenoids, one of the most diverse classes of natural products, have been used for centuries as active ingredients in essential oils and Chinese medicines and are of interest for many industrial applications ranging from low-calorie sweeteners to cosmetic ingredients and vaccine adjuvants. However, not only can the extraction from plant material be cumbersome due to low concentrations of the specific triterpenoid, but concerns are also increasing regarding the sustainability of wild plant harvest while meeting market demands. The alternative is to produce triterpenoids with engineered microbes. Here, we present a generally applicable strategy for triterpenoid production in the yeast Saccharomyces cerevisiae based on a modified oxidosqualene cyclase Erg7. The modification reduces the flux into the sterol pathway while increasing the precursor supply for triterpenoid production. The minimally engineered strain was exploited for the exemplary production of the lupane triterpenoids betulin, betulin aldehyde, and betulinic acid at a total titer above 6 g/L, the highest reported so far. To further highlight the chassis concept, squalene, oleanane- and dammarane-type triterpenoids were synthesized to titers at a similar gram scale. We propose the developed bakers yeast as a host for the thousands of triterpenoid synthesis pathways from plants, reducing the pressure on the natural resources.

bioengineering↗

bioRxiv2022

Validated Preclinical Murine Model for Therapeutic Testing against Multidrug Resistant Pseudomonas aeruginosa

The rise in infections caused by antibiotic resistant bacteria is outpacing the development of new antibiotics. The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are a group of clinically important bacteria that have developed resistance to multiple antibiotics and are commonly referred to as multidrug resistant (MDR). The medical and research communities have recognized that without new antimicrobials, infections by MDR bacteria will soon become a leading cause of morbidity and mortality. Therefore, there is an ever growing need to expedite the development of novel antimicrobials to combat these infections. Toward this end, we set out to refine an existing murine model of pulmonary Pseudomonas aeruginosa infection to generate a robust preclinical tool that can be used to rapidly and accurately predict novel antimicrobial efficacy. This refinement was achieved by characterizing the virulence of a panel of genetically diverse MDR P. aeruginosa strains in this model, both by LD50 analysis and natural history studies. Further, we defined two antibiotic regimens (aztreonam and amikacin) that can be used a comparators during the future evaluation of novel antimicrobials, and validated that the model can effectively differentiate between successful and unsuccessful treatment as predicted by in vitro inhibitory data. This validated model represents an important tool in our arsenal to develop new therapies to combat MDR P. aeruginosa, with the ability to provide rapid preclinical evaluation of novel antimicrobials that can also serve to support data from clinical studies during the investigational drug development process.

microbiology↗

bioRxiv2022

Systems Analysis of de novo Mutations in Congenital Heart Diseases Identified a Molecular Network in Hypoplastic Left Heart Syndrome

Congenital heart diseases (CHD) are a class of birth defects affecting [~]1% of live births. These conditions are hallmarked by extreme genetic heterogeneity, and therefore, despite a strong genetic component, only a very handful of at-risk loci in CHD have been identified. We herein introduced systems analyses to uncover the hidden organization on biological networks of genomic mutations in CHD, and leveraged network analysis techniques to integrate the human interactome, large-scale patient exomes, the fetal heart spatial transcriptomes, and single-cell transcriptomes of clinical samples. We identified a highly connected network in CHD where most of the member proteins had previously uncharacterized functions in regulating fetal heart development. While genes on the network displayed strong enrichment for heart-specific functions, a sub-group, active specifically at early developmental stages, also regulates fetal brain development, thereby providing mechanistic insights into the clinical comorbidities between CHD and neurodevelopmental conditions. At a small scale, we experimentally verified previously uncharacterized cardiac functions of several novel proteins employing cellular assays and gene editing techniques. At a global scale, our study revealed developmental dynamics of the identified CHD network and observed the strongest enrichment for pathogenic mutations in the network specific to hypoplastic left heart syndrome (HLHS). Our single-cell transcriptome analysis further identified pervasive dysregulation of the network in cardiac endothelial cells and the conduction system in the HLHS left ventricle. Taken together, our systems analyses identified novel factors in CHD, revealed key molecular mechanisms in HLHS, and provides a generalizable framework readily applicable to studying many other complex diseases.

systems biology↗

bioRxiv2022

Impact of glycoengineering and immunogenicity on the anti-cancer activity of a plant-made lectin-Fc fusion protein

Plants are an efficient production platform for manufacturing glycoengineered monoclonal antibodies and antibody-like molecules. Avaren-Fc (AvFc) is a lectin-Fc fusion protein or lectibody produced in Nicotiana benthamiana, which selectively recognizes cancer-associated high-mannose glycans. In this study, we report the generation of a glycovariant of AvFc that is devoid of plant glycans, including the core 1,3-fucose and {beta}1,2-xylose residues. The successful removal of these glycans was confirmed by glycan analysis using HPLC. This variant, AvFc{Delta}XF, has significantly higher affinity for Fc gamma receptors and induces higher levels of luciferase expression in an antibody-dependent cell-mediated cytotoxicity (ADCC) reporter assay against B16F10 murine melanoma cells without inducing apoptosis or inhibiting proliferation. In the B16F10 flank tumor mouse model, we found that systemic administration of AvFc{Delta}XF, but not an aglycosylated AvFc variant lacking affinity for Fc receptors, significantly delayed the growth of tumors, suggesting that Fc-mediated effector functions were integral. AvFc{Delta}XF treatment also significantly reduced lung metastasis of B16F10 upon intravenous challenge whereas a sugar-binding-deficient mutant failed to show efficacy. Lastly, we determined the impact of anti-drug antibodies (ADAs) on drug activity in vivo by pretreating animals with AvFc{Delta}XF before implanting tumors. Despite a significant ADA response induced by the pretreatment, we found that the activity of AvFc{Delta}XF was unaffected by the presence of these antibodies. These results demonstrate that glycoengineering is a powerful strategy to enhance AvFcs antitumor activity.

cancer biology↗

bioRxiv2022

Chemical genetic screening identifies nalacin as an inhibitor of GH3 amido synthetase for auxin conjugation

Root system is critical for plant growth and development. To develop plant growth regulators functioning in root development, we performed a phenotype-based chemical screen in Arabidopsis and identified a chemical, nalacin, that mimicked the effects of auxin on root development. Genetic, pharmacological and biochemical approaches demonstrated that nalacin exerts its auxin-like activities by inhibiting indole-3-acetic acid (IAA) conjugation that is mediated by Gretchen Hagen 3 (GH3) acyl acid amido synthetases. The crystal structure of Arabidopsis GH3.6 in complex with D4 (a derivative of nalacin) together with docking simulation analysis revealed the molecular basis of the inhibition of group II GH3 by nalacin. Sequence alignment analysis indicated broad bioactivities of nalacin and D4 as inhibitors of GH3s in vascular plants, which were confirmed, at least, in tomato and rice. In summary, our work identifies nalacin as a potent inhibitor of IAA conjugation mediated by group II GH3 that plays versatile roles in hormone-regulated plant development and has potential applications in both basic research and agriculture.

plant biology↗

bioRxiv2022

Quantifying portable genetic effects and improving cross-ancestry genetic prediction with GWAS summary statistics

Polygenic risk scores (PRS) calculated from genome-wide association studies (GWAS) of Europeans are known to have substantially reduced predictive accuracy in non-European populations, limiting its clinical utility and raising concerns about health disparities across ancestral populations. Here, we introduce a novel statistical framework named X-Wing to improve predictive performance in ancestrally diverse populations. X-Wing quantifies local genetic correlations for complex traits between populations, employs a novel annotation-dependent estimation procedure to amplify correlated genetic effects between populations, and combines multiple population-specific PRS into a unified score with GWAS summary statistics alone as input. Through extensive benchmarking, we demonstrate that X-Wing pinpoints portable genetic effects and substantially improves PRS performance in non-European populations, showing 18.7%-122.1% gain in predictive R2 compared to state-of-the-art methods based on GWAS summary statistics. Overall, X-Wing addresses critical limitations in existing approaches and may have broad applications in cross-population polygenic prediction.

genetics↗

bioRxiv2022

Comprehensive Analysis of the Expression and Prognosis for PSMBs in Clear Cell Renal Cell Carcinoma

BackgroundClear cell renal cell carcinoma (ccRCC) is one of the most common malignances with an ever-increasing incidence and high mortality. Although comprehensive therapy has made great progress in recent years, the prognosis of most ccRCC patients is still poor. The proteasome {beta} subunits (PSMBs) are a group of genes composing the ubiquitin-proteasome pathway, which is the principal mechanism of protein catabolism in mammalian cytoplasm and nucleus and is essential for the regulation of almost all cellular processes. Growing evidence show s that the PSMBs play an important role in the occurrence and progression of various cancers. However, the expression and prognostic value of PSMBs in ccRCC have not been evaluated. MethodsTo solve this issue, ONCOMINE, UALCAN, Human Protein Atlas, cBioPortal, Metascape, GeneMANIA, STRING, DAVID 6.8, TIMER were used in this study. ResultsThe transcriptional expression levels of PSMB2/4/7/8/9/10 in ccRCC tissues were found to be significantly upregulated, and the mRNA expression levels of PSMB1/2/3/4/8/9/10 were associated with advanced tumor stage and tumor grade. Besides, higher mRNA expression of PSMB1/2/3/4/5/6/7/10 were associated with a shorter overall survival (OS). Furthermore, the protein expression level of PSMB4/7/8/9/10 in ccRCC was higher than normal renal tissues. Significant relationships were also found between the expression of PSMBs and the infiltration of immune-related cells. ConclusionsThe present study implied that PSMB4 and PSMB10 might act as potential therapy targets and prognostic biomarkers in ccRCC, which may contribute to available knowledge, improve the treatment designs, and enhance the accuracy of prognosis for patients with ccRCC.

bioinformatics↗

bioRxiv2022

Analysis and Identification of Necroptosis Landscape on Therapy and Prognosis in Bladder Cancer

Bladder cancer (BLCA) is one of the most common malignant tumors of the urinary system, but current therapeutic strategy based on chemotherapy and immune checkpoint inhibitors (ICIs) therapy cannot meet the treatment needs, which mainly owing to the endogenous or acquired apoptotic resistance of cancer cells. Targeting necroptosis provides a novel strategy for chemotherapy, targeted drugs, and improves the efficacy of ICIs because of strong immunogenicity of necroptosis. Therefore, we systemically analyzed necroptosis landscape on therapy and prognosis in BLCA. We firstly divided BLCA patients from The Cancer Genome Atlas (TCGA) database into two necroptosis-related clusters (C1 and C2). Necroptosis C2 showed a significantly better prognosis than C1, and the differential genes of C2 and C1 were mainly related to the immune response according to GO and KEGG analysis. Next, we constructed a novel necroptosis related genes (NRGs) signature consisting of SIRT6, FASN, GNLY, FNDC4, SRC, ANXA1, AIM2, and IKBKB to predict the survival of TCGA-BLCA cohort, the accuracy of NRGsocre was also verified by external datasets. In addition, a nomogram combining NRGscore and several clinicopathological features was established to predict the BLCA patients OS more accurately and conveniently. We also found that NRGscore was significantly related to the infiltration levels of CD8 T cells, NK cells, and iDC cells, the gene expression of CTLA4, PD1, TIGIT, and LAG3 of TME, the sensitivity to chemotherapy and targeted agents in BLCA patients. In conclusion, the NRGscore has an excellent performance in evaluating the prognosis, clinicopathologic features, tumor microenvironment (TME) and therapeutic sensitivity of BLCA patients, which could be utilized as a guide for chemotherapy, ICIs therapy, and combination therapy.

cancer biology↗

bioRxiv2022

Comparative genomic and crystal structure analyses identify a collagen glucosyltransferase from Acanthamoeba Polyphaga Mimivirus

Humans and Acanthamoeba Polyphaga Mimivirus share numerous homologous genes, including collagens and collagen-modifying enzymes. To explore the homology, we performed a genome-wide comparison between human and mimivirus using DELTA-BLAST (Domain Enhanced Lookup Time Accelerated BLAST) and identified 52 new mimiviral proteins that are homologous with human proteins. To gain functional insights into mimiviral proteins, their human protein homologs were organized into Gene Ontology (GO) and REACTOME pathways to build a functional network. Collagen and collagen-modifying enzymes form the largest subnetwork with most nodes. Further analysis of this subnetwork identified a putative collagen glycosyltransferase R699. Protein expression test suggested that R699 is highly expressed in E coli, unlike the human collagen-modifying enzymes. Enzymatic activity assays showed that R699 catalyzes the conversion of unique galactosylhydroxylysine within the GXXXUG motif (U=galactosylhydroxylysine) to glucosylgalactosylhydroxylysine on collagen using uridine diphosphate glucose (UDP-Glc) as a sugar donor, suggesting R699 is a mimiviral collagen galactosylhydroxylysyl glucosyltransferase (GGT) with defined substrate specificity. Structural study of R699 produced the first crystal structure of a collagen GGT with a visible UDP-Glc. Sugar moiety of the UDP-Glc resides in a previously unrecognized pocket. Mn2+ coordination and nucleoside-diphosphate binding site are conserved among GGT family members and critical for R699s collagen GGT activity. To facilitate further analysis of human and mimiviral homologous proteins, we presented an interactive and searchable genome-wide comparison website for quickly browsing human and Acanthamoeba Polyphaga Mimivirus homologs, which is available at RRID Resource ID: SCR_022140 or https://guolab.shinyapps.io/app-mimivirus-publication/.

biochemistry↗

bioRxiv2022

A cocktail containing two synergetic antibodies broadly neutralizes SARS-CoV-2 and its variants including Omicron BA.1 and BA.2

Neutralizing antibodies (NAbs) can prevent and treat infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, continuously emerging variants, such as Omicron, have significantly reduced the potency of most known NAbs. The selection of NAbs with broad neutralizing activities and the identification of conserved critical epitopes are still urgently needed. Here, we identified an extremely potent antibody (55A8) by single B-cell sorting from convalescent SARS-CoV-2-infected patients that recognized the receptor-binding domain (RBD) in the SARS-CoV-2 spike (S) protein. 55A8 could bind to wild-type SARS-CoV-2, Omicron BA.1 and Omicron BA.2 simultaneously with 58G6, a NAb previously identified by our group. Importantly, an antibody cocktail containing 55A8 and 58G6 (2-cocktail) showed synergetic neutralizing activity with a half-maximal inhibitory concentration (IC50) in the picomolar range in vitro and prophylactic efficacy in hamsters challenged with Omicron (BA.1) through intranasal delivery at an extraordinarily low dosage (25 g of each antibody daily) at 3 days post-infection. Structural analysis by cryo-electron microscopy (cryo-EM) revealed that 55A8 is a Class III NAb that recognizes a highly conserved epitope. It could block angiotensin-converting enzyme 2 (ACE2) binding to the RBD in the S protein trimer via steric hindrance. The epitopes in the RBD recognized by 55A8 and 58G6 were found to be different and complementary, which could explain the synergetic mechanism of these two NAbs. Our findings not only provide a potential antibody cocktail for clinical use against infection with current SARS-CoV-2 strains and future variants but also identify critical epitope information for the development of better antiviral agents.

immunology↗

bioRxiv2022

LRRK2 Phosphorylates Neuronal Elav RNA-Binding Proteins to RegulatePhenotypes Relevant to Parkinson's Disease

Parkinsons disease (PD) is characterized by accumulation of -synuclein and the loss of dopaminergic neurons. Mutations which cause an increase in the kinase activity of Leucine-Rich-Repeat Kinase-2 (LRRK2) are a major inherited cause of PD. Research continues to determine which targets LRRK2 phosphorylates to cause disease. Polymorphisms in the locus of ELAVL4, an RNA-binding protein are a risk-factor for Parkinsons disease and an ELAV family member was identified in Drosophila as required for pathology instigated by human mutant LRRK2. We discovered that three neuronal ELAVs including ELAVL4 (also known as HuD) are phosphorylated by LRRK2. This controls binding of neuronal ELAVs to mRNA and their post- transcriptional regulation of mRNA abundance and splicing in neuronal cell lines and the mouse midbrain. LRRK2 G2019S functionally inhibits neuronal ELAVs effects on mRNA abundance, while enhancing their effects on mRNA splicing. The combination of LRRK2 G2019S and ELAVL4-/- causes accumulation of LRRK2 and -synuclein, loss of dopaminergic neurons and motor deficits. Targets of neuronal ELAVs are also selectively misregulated in cells and tissues of PD patients. Together, this suggests that misregulation of neuronal ELAVs, triggered by LRRK2 mutations may contribute to the characteristic pathology of Parkinsons disease. Brief SummaryLRRK2, a kinase linked to Parkinsons disease, phosphorylates the neuronal ELAV RNA-binding proteins to aggravate key hallmarks of Parkinsons disease including accumulation of -synuclein and motor deficits in mice.

cell biology↗

bioRxiv2022

Drug design and repurposing with a sequence-to-drug paradigm

Drug development based on target proteins has been a successful approach in recent decades. A conventional structure-based drug design pipeline is a complex, human-engineered pipeline with multiple independently optimized steps. Advances in end-to-end differentiable learning suggest the potential benefits of similarly reformulating drug design. Here, we proposed a new sequence-to-drug paradigm that discovers drug-like small-molecule modulators directly from protein sequences and validated this concept for the first time in three stages. First, we designed TransformerCPI2.0 as a core tool for the sequence-to-drug paradigm, which exhibited competitive performance with conventional structure-based drug design approaches. Second, we validated the binding knowledge that TransformerCPI2.0 has learned. Third, we applied a sequence-to-drug paradigm to discover new hits for E3 ubiquitin-protein ligases: speckle-type POZ protein (SPOP), ring finger protein 130 (RNF130) which does not have a 3D structure, and repurposed proton pump inhibitors (PPIs) for ADP-ribosylation factor 1 (ARF1). This first proof of concept shows that the sequence-to-drug paradigm is a promising direction for drug development.

molecular biology↗

bioRxiv2022

Target Class Profiling of Small Molecule Methyltransferases

Target class profiling (TCP) is a chemical biology approach to investigating understudied biological target classes. TCP is achieved by developing a generalizable assay platform and screening curated compound libraries to interrogate the chemical biological space of members of an enzyme family with clinical and biological importance. In this work we took a TCP approach to investigate inhibitory activity across a set of small molecule methyltransferases, a subclass of methyltransferase enzymes, with the goal of creating a launchpad to explore this largely understudied target class. Using the representative enzymes nicotinamide N-methyltransferase (NNMT), phenylethanolamine N-methyltransferase (PNMT), histamine N-methyltransferase (HNMT), glycine N-methyltransferase (GNMT), catechol O-methyltransferase (COMT), and guanidinoacetate N-methyltransferase (GAMT), we optimized high-throughput screening (HTS)-amenable assays to screen 27,574 unique small molecules against all targets. From this dataset we identified a novel inhibitor which selectively inhibits the small molecule methyltransferase HNMT, and demonstrated how this platform approach can be leveraged for a targeted drug discovery campaign using the example of HNMT.

biochemistry↗

bioRxiv2022

Integration of multi-omics data reveals interplay between brassinosteroid and TORC signaling in Arabidopsis

Brassinosteroids (BR) and Target of Rapamycin Complex (TORC) are two major actors coordinating plant growth and stress responses. BRs function through a signaling pathway to extensively regulate gene expression and TORC is known to regulate translation and autophagy. Recent studies revealed that these two pathways crosstalk, but a system-wide view of their interplay is still missing. Thus, we quantified the level of 23,975 transcripts, 11,183 proteins, and 27,887 phosphorylation sites in wild-type Arabidopsis and in mutants with altered levels of either BRASSINOSTEROID INSENSITIVE 2 (BIN2) or REGULATORY ASSOCIATED PROTEIN OF TOR 1B (RAPTOR1B), two key players in BR and TORC signaling, respectively. We found that perturbation of BIN2 or RAPTOR1B levels affects a common set of gene-products involved in growth and stress responses. Furthermore, we used the multi-omic data to reconstruct an integrated signaling network. We screened 41 candidate genes identified from the reconstructed network and found that loss of function mutants of many of these proteins led to an altered BR response and/or modulated autophagy activity. Altogether, these results establish a predictive network that defines different layers of molecular interactions between BR-or TORC-regulated growth and autophagy.

plant biology↗

bioRxiv2022

Recent Reconfiguration Of An Ancient Developmental Gene Regulatory Network In Heliocidaris Sea Urchins

Changes in developmental gene regulatory networks (dGRNs) underlie much of the diversity of life1, but the evolutionary mechanisms that operate on interactions with these networks remain poorly understood. Closely related species with extreme phenotypic divergence provide a valuable window into the genetic and molecular basis for changes in dGRNs and their relationship to adaptive changes in organismal traits. Here we analyze genomes, epigenomes, and transcriptomes during early development in two sea urchin species in the genus Heliocidaris that exhibit highly divergent life histories and in an outgroup species. Signatures of positive selection and changes in chromatin status within putative gene regulatory elements are both enriched on the branch leading to the derived life history, and particularly so near dGRN genes; in contrast, positive selection within protein-coding regions have at most a modest enrichment in branch and function. Single-cell transcriptomes reveal a dramatic delay in cell fate specification in the derived state, which also has far fewer open chromatin regions, especially near dGRN genes with conserved roles in cell fate specification. Experimentally perturbing the function of three key transcription factors reveals profound evolutionary changes in the earliest events that pattern the embryo, disrupting regulatory interactions previously conserved for [~]225 million years. Together, these results demonstrate that natural selection can rapidly reshape developmental gene expression on a broad scale when selective regimes abruptly change and that even highly conserved dGRNs and patterning mechanisms in the early embryo remain evolvable under appropriate ecological circumstances.

evolutionary biology↗

bioRxiv2022

CLE42 Delays Leaf Senescence by Antagonizing Ethylene Pathway in Arabidopsis

Leaf senescence is the final stage of leaf development and is influenced by numerous internal and environmental factors. CLE family peptides are plant-specific peptide hormones that regulate various developmental processes. However, the role of CLE in regulating leaf senescence remains unclear. Here, we found that CLE42 is a negative regulator of leaf senescence by using a CRISPR/Cas9-produced CLE mutant collection. The cle42 mutant displayed earlier senescence phenotypes, while overexpression of CLE42 delayed age-dependent and dark-induced leaf senescence. Moreover, application of the synthesized 12-aa peptide (CLE42p) also delayed leaf senescence under natural and dark conditions. CLE42 and CLE41/44 displayed functional redundancy in leaf senescence, and the cle41 cle42 cle44 triple mutant displayed more pronounced earlier senescence phenotypes than any single mutant. Analysis of differentially expressed genes obtained by RNA-Seq methodology revealed that ethylene pathway was suppressed by overexpressing CLE42. Moreover, CLE42 suppressed ethylene biosynthesis and thus promoted the protein accumulation of EBF, which in turn decreased the function of EIN3. Accordingly, mutation of EIN3/EIL1 or overexpression of EBF1 suppressed the earlier senescence phenotypes of the cle42 mutant. Together, our results reveal that the CLE peptide hormone regulates leaf senescence by communicating with ethylene pathway.

plant biology↗

bioRxiv2022

Brassinosteroids modulate autophagy through phosphorylation of RAPTOR1B by the GSK3-like kinase BIN2 in Arabidopsis

Macroautophagy/autophagy is a conserved recycling process that maintains cellular homeostasis during environmental stress. Autophagy is negatively regulated by TARGET OF RAPAMYCIN (TOR), a nutrient-regulated protein kinase that in plants is activated by several phytohormones, leading to increased growth. However, the detailed molecular mechanisms by which TOR integrates autophagy and hormone-signaling are poorly understood. Here, we show that TOR modulates brassinosteroid (BR)-regulated plant growth and stress-response pathways. Active TOR was required for full BR-induced growth in Arabidopsis thaliana. Autophagy was constitutively up-regulated upon blocking BR biosynthesis or signaling, and down-regulated by increasing the activity of the BR pathway. BRASSINOSTEROID-INSENSITIVE 2 (BIN2) kinase, a GSK3-like kinase functioning as a negative regulator in BR signaling, directly phosphorylated Regulatory-Associated Protein of TOR 1B (RAPTOR1B), a substrate-recruiting subunit in the TOR complex, at a conserved serine residue within a typical BIN2 phosphorylation motif. Mutation of RAPTOR1B serine 916 to alanine, to block phosphorylation by BIN2, repressed autophagy and increased phosphorylation of the TOR substrate autophagy-related protein 13a (ATG13a). By contrast, this mutation had only a limited effect on growth. We present a model in which RAPTOR1B is phosphorylated and inhibited by BIN2 when BRs are absent, activating the autophagy pathway. When BRs signal and inhibit BIN2, RAPTOR1B is thus less inhibited by BIN2 phosphorylation. This leads to increased TOR activity and ATG13a phosphorylation, and decreased autophagy activity. Our studies define a new mechanism by which coordination between BR and TOR signaling pathways helps to maintain the balance between plant growth and stress responses.

plant biology↗

bioRxiv2022

Improved Heat Tolerance in Heat-acclimated Mice: the Probable Role of the PD-L1 Pathway

Heat stroke is a life-threatening illness and is related to systematic inflammation-induced multiple organ dysfunction. Available evidence indicates that the severity of the systematic inflammatory response in heat stroke may be related to the changes in immune regulation brought by heat acclimation. However, the mechanisms of heat acclimation are still unclear. Here, we assessed the differences in immunocyte subsets in the spleen and lymph nodes of heat-acclimated and unacclimated mice. A higher frequency of CD4+Foxp3+ Tregs was observed in heat-acclimated mice. Our results indicated that the improved heat tolerance exhibited during acute heat stress exposure was related to an increased number of Tregs. In heat-acclimated mice, an increase in the number of Tregs was able to mitigate the recruitment of neutrophils, inhibit the activation of neutrophils, and suppress the severity of acute inflammation. Increased differentiation and development of Tregs in peripheral immune organs in heat-acclimated mice might stem from enhanced expression of Foxp3 and PD-L1. Our results strongly suggest that the regulatory function of increased Tregs on neutrophils may be regulated through the PD-1/PD-L1 pathway. The anti-inflammatory effects of Tregs have never been studied in the context of heat stress-induced systemic inflammation. Thus, our results on immunoregulation involving Tregs in heat-acclimated mice might be significant for devising a potential treatment for systemic inflammatory response syndrome and heatstroke.

immunology↗