Biology subjects

Xie, Q.

Publications and source records attributed to Xie, Q..

At least 55 records · Page 3Linked to original sources

bioRxiv2024

SUV39H1 Preserves Cancer Stem Cell Chromatin State and Properties in Glioblastoma

Of the more than 100 types of brain cancer, glioblastoma (GBM) is the deadliest. As GBM stem cells (GSCs) are considered to be responsible for therapeutic resistance and tumor recurrence, effective targeting and elimination of GSCs could hold promise for preventing GBM recurrence and achieving potential cures. We show here that SUV39H1, which encodes a histone-3, lysine-9 methyltransferase, plays a critical role in GSC maintenance and GBM progression. Upregulation of SUV39H1 was observed in GBM samples compared to normal brain tissues, and knockdown of SUV39H1 in patient-derived GSCs impaired their proliferation and stemness. Single-cell RNA-seq analysis demonstrated restricted expression of SUV39H1 is in GSCs relative to non-stem GBM cells, likely due to super-enhancer-mediated transcriptional activation, while whole cell RNA-seq analysis revealed that SUV39H1 regulates G2/M cell cycle progression, stem cell maintenance, and cell death pathways in GSCs. By integrating the RNA-seq data with ATAC-seq (assay for transposase-accessible chromatin followed by sequencing), we further demonstrated altered chromatin accessibility in key genes associated with these pathways following SUV39H1 knockdown. Treatment with chaetocin, a SUV39H1 inhibitor, mimicked the functional effects of SUV39H1 knockdown in GSCs and sensitized GSCs to the GBM chemotherapy drug temozolomide. Furthermore, targeting SUV39H1 in vivo using a patient-derived xenograft model for GBM inhibited GSC-driven tumor formation. This is the first report demonstrating a critical role for SUV39H1 in GSC maintenance. SUV39H1-mediated targeting of GSCs could enhance the efficacy of existing chemotherapy, presenting a promising strategy for improving GBM treatment and patient outcomes. HighlightsO_LISUV39H1 is upregulated in GBM, especially GSCs C_LIO_LITargeting SUV39H1 disrupts GSC maintenance and sensitizes GSCs to TMZ C_LIO_LITargeting SUV39H1 alters chromatin accessibility at cell cycle and stemness genes C_LIO_LITargeting SUV39H1 suppresses GSC-driven tumors in a patient-derived xenograft model C_LI

cancer biology↗

bioRxiv2024

Macrophages facilitate interclonal cooperation-induced tumor heterogeneity and malignancy by activating the innate immune signaling

Tumor heterogeneity is a common hallmark of cancer and is considered a major cause of treatment failure and relapse, yet it remains poorly understood how various types of cells communicate within the tumor microenvironment (TME) to regulate tumor progression in vivo. Here we establish a tumor heterogeneity model in Drosophila eye epithelium by mutating the tricellular junction protein M6 in cells surrounding RasV12benign tumors and dissect the in vivo mechanisms underlying interclonal cooperation-induced malignancy by utilizing sophisticated genetic techniques in conjunction with single-cell RNA sequencing (scRNA-seq). Our findings reveal that loss of M6 facilitates the malignant transformation of neighboring RasV12 tumors by activating the Toll signaling, the innate immune response pathway. Notably, inhibiting Toll signaling impedes tumor progression, whereas its activation synergistically promotes RasV12 tumor malignancy by inactivating the Hippo pathway. Mechanistically, RasV12 tumors surrounded by M6 mutant clones lead to increased recruitment of hemocytes, which are the equivalent of macrophages in Drosophila, in a JNK pathway-dependent manner. Consequently, these tumor-associated macrophages secrete the Spatzle (Spz) ligand, which subsequently activates the Toll receptor within the RasV12 tumors, thereby triggering tumorigenesis. In summary, our study elucidates the complex in vivo interactions between genetically distinct oncogenic cells and between tumors and macrophages, shedding light on how macrophages exploit the innate immune signaling within tumors to regulate tumor heterogeneity and promote tumor progression. Significance statementIntratumoral heterogeneity profoundly affects cancer development and treatment in human tumors. The intricate nature of tumor cells and the presence of diverse cell types pose challenges to uncovering in vivo mechanisms responsible for heterogeneity. Our Drosophila tumor heterogeneity model reveals that fruit fly macrophages promotes both tumor heterogeneity and malignancy. Following recruitment by tumor cells, these macrophages secrete the ligand Spz to activate the Toll signaling pathway within tumor cells, which subsequently inactivates the Hippo pathway to drive tumorigenesis. Our study highlights the crucial role of hemocytes as intermediaries in coordinating tumor heterogeneity and facilitating intercellular communication between different cells within the TME.

cancer biology↗

bioRxiv2024

Nuclear receptor E75/NR1D2 drives tumor malignant transformation by integrating Hippo and Notch pathways

Hormone therapy resistance and the ensuing aggressive progression of tumors present a significant clinical challenge. However, the mechanisms underlying the induction of tumor malignancy by hormone inhibition remain poorly understood. Here we show that Drosophila malignant epithelial tumors exhibit a comparable decrease in ecdysone signaling, the primary steroid hormone pathway in Drosophila. Furthermore, we find that ectopic expression of the nuclear receptor E75 partially mimics ecdysone signaling inhibition, specifically promoting the malignant transformation of benign tumors by integrating the Hippo and Notch signaling pathways. Genome-wide DNA binding profiles and biochemistry data reveal that E75 not only physically interacts with the transcription factors of both Hippo and Notch pathways, but also exhibits widespread co-binding to their target genes, thus contributing to tumor malignancy. Moreover, we validate these findings by demonstrating that depletion of NR1D2, the mammalian equivalent of E75, inhibits the activation of Hippo and Notch target genes, impeding glioblastoma progression in vivo. In summary, our study unveils a previously unrecognized mechanism by which hormone inhibition promotes tumor malignant transformation, while providing a conserved mechanistic understanding of how Hippo and Notch pathways are integrated by the oncogene E75/NR1D2 during tumor progression.

cancer biology↗

bioRxiv2024

CAMSAP3 Forms Dimers via its lapha-helix Domain that Directly Stabilize Non-centrosomal Microtubule Minus Ends

Microtubules are vital components of the cytoskeleton. Their plus ends are dynamic and respond to changes in cell morphology, while the minus ends are stable and serve a crucial role in microtubule seeding and maintaining spatial organization. In mammalian cells, the calmodulin-regulated spectrin-associated proteins (CAMSAPs), play a key role in directly regulating the dynamics of non-centrosomal microtubules minus ends. However, the molecular mechanisms are not yet fully understood. Our study reveals that CAMSAP3 forms dimers through its C-terminal -helix; this dimerization not only enhances the microtubule-binding affinity of the CKK domain but also enables the CKK domain to regulate the dynamics of microtubules. Furthermore, CAMSAP3 also specializes in decorating at the minus end of microtubules through the combined action of the microtubule-binding domain (MBD) and the C-terminal -helix, thereby achieving dynamic regulation of the minus ends of microtubules. These findings are crucial for advancing our understanding and treatment of diseases associated with non-centrosomal microtubules. SignificanceOur study reveals the molecular mechanism of how CAMSAP3, a key regulator of non-centrosomal microtubule dynamics, directly regulates the dynamics of non-centrosomal microtubule minus ends through CKK domain. CAMSAP3 forms dimers through its C-terminal -helix, which enhances the CKK domain of CAMSAP3 binding to microtubule minus ends and confers stability of them. This finding is not limited to CAMSAP3, but can also be applied to the understanding of the regulation of non-centrosomal microtubule minus end stability by CAMSAP family proteins. Our findings deepen our comprehension of cellular structure and function, offering insights into the role of microtubules in cellular integrity and disease. This study fills a significant knowledge gap and lays the foundation for future research into the complex balance of microtubule dynamics required for cellular health and disease prevention.

cell biology↗

bioRxiv2024

MARK2 regulates Golgi apparatus reorientation by phosphorylation of CAMSAP2 in directional cell migration

The reorientation of the Golgi apparatus is crucial for cell migration and is regulated by multi-polarity signals. A number of non-centrosomal microtubules anchor at the surface of the Golgi apparatus and play a vital role in the Golgi reorientation, but how the Golgi are regulated by polarity signals remains unclear. Calmodulin-regulated spectrin-associated protein 2 (CAMSAP2) is a protein that anchors microtubules to the Golgi, a cellular organelle. Our research indicates that CAMSAP2 is dynamically localized at the Golgi during its reorientation processing. Further research shows that CAMSAP2 is potentially regulated by a polarity signaling molecule called MARK2, which interacts with CAMSAP2. We used mass spectrometry to find that MARK2 phosphorylates CAMSAP2 at serine 835, which affects its interaction with the Golgi associated protein USO1 but not with CG-NAP or CLASPs. This interaction is critical for anchoring microtubules to the Golgi during cell migration, altering microtubule polarity distribution, and aiding Golgi reorientation. Our study reveals an important signaling pathway in Golgi reorientation during cell migration, which can provide insights for research in cancer cell migration, immune response, and targeted drug development.

cell biology↗

bioRxiv2024

Ancient cyanobacterial proto-circadian clock adapted to short day-night cycles ~ 0.95 billion years ago

In the early history, the Earth rotation was much faster; however, how ancient organisms adapted to the day-night cycles of that time remains unclear. We resurrected the ancestor KaiABC (anKaiABC) genes circa 0.95 billion years (Ga) ago when the daily-night cycling period was [~] 18 h. Compared with its contemporary counterpart KaiC, the anKaiC protein shows subtle structural differences, and the activities of kinase, phosphatase activities, and adenosine triphosphatase (ATPase) of anKaiC are lower. The anKaiAB proteins are less effective in regulating KaiC/anKaiC phosphorylation status. The anKaiABC system does not sustain an endogenous oscillation but it can be entrained by an 18-h light/dark cycle. The strain expressing anKaiABC shows better adaptation under 9-h light/9-h dark cycles (LD9:9) which mimic the 18-h day-night cycles. These findings suggest that the ancient cyanobacterial proto-circadian system may not be endogenous, but it conferred the capability to adapt to daily cycles [~] 0.95 Ga ago.

evolutionary biology↗

bioRxiv2024

Multi-omic Analysis Identifies Glioblastoma Dependency on H3K9me3 Methyltransferase Activity

Histone H3 Lysine 9 dimethylation or trimethylation (H3K9me2 or H3K9me3) marks more than half of the human genome, particularly in heterochromatin regions and specific genes within euchromatic regions. Enzymes catalyzing the methylation of H3K9 have individually been associated with the modulation of gene expression patterns involved in cancer progression, including suppressor of variegation 3-9 homologue 1 (SUV39H1), SUV39H2, SET domain bifurcated 1 (SETDB1), SETDB2, euchromatic histone-lysine N-methyltransferase 1 and 2 (EHMT1/2). However, a comprehensive comparison and understanding of the characteristics and mechanisms of these chromatin-modifying enzymes in cancers remains incompletely understood. In this study, we demonstrated that these six H3K9 methyltransferases differentially expressed in tumors and correlated expression with somatic copy number variations (CNVs) and DNA methylation patterns. Through integrative multi-omics analyses, we identified SUV39H1, SUV39H2, and SETDB1 as the key players among the six H3K9 methyltransferases that exhibited the most significant associations with cancer phenotypes. By incorporating SUV39H1, SUV39H2, and SETDB1, we developed a novel signature termed "H3K9me3 MtSig" (H3K9me3 methyltransferases signature). H3K9me3 MtSig was unique for various tumor types, had prognostic implications and was linked to significant signaling pathways, particularly in glioblastoma (GBM). Furthermore, elevated H3K9me3 MtSig was confirmed in GBM patient-derived cells and tissues. In addition, single-cell expression analysis of H3K9me3 MtSig in GBM tissues demonstrated a pattern related to the G2/M cell cycle and was negatively correlated with immune responses. H3K9me3-mediated repetitive sequence silencing by H3K9me3 MtSig, determined using ChIP-sequencing, contributed to these phenotypes, and inhibiting H3K9me3 MtSig in patient-derived GBM cells suppressed proliferation and increased immune responses. Translationally, H3K9me3 MtSig performed as an independent prognostic factor in a clinical prediction model, and drug susceptibility screening integrating H3K9me3 MtSig identified potential biomarkers and therapeutics for GBM. In summary, H3K9me3 MtSig has the potential to elucidate novel prognostic markers, therapeutic targets, and predictors of treatment response in GBM and other cancer types for clinical intervention. SignificanceDifferential expressions of H3K9 methyltransferases across cancers correlates with clinical outcomes; in GBM, an H3K9me3 methyltransferase signature links to G2/M cell cycle, immune response pathways, and prognosis, aiding biomarker and treatment development.

cancer biology↗

bioRxiv2024

EcoHIV Infection Modulates the Effects of Cocaine Exposure Pattern and Abstinence on Cocaine Seeking and Neuroimmune Protein Expression in Male Mice

Cocaine use disorders (CUDs) and human immunodeficiency virus (HIV) remain persistent public health dilemmas throughout the world. One major hurdle for treating CUD is the increase in cocaine craving and seeking behavior that occurs over a protracted period of abstinence, an effect known as the incubation of craving. Little is known about how HIV may modulate this process. Thus, we sought to examine the impact of chronic HIV infection on the incubation of cocaine craving and associated changes in the central and peripheral immune systems. Here, mice were inoculated with EcoHIV, which is a chimeric HIV-1 construct that produces chronic HIV infection in mice. EcoHIV- and sham- infected mice were conditioned with cocaine daily or intermittently in a conditioned place preference (CPP) paradigm, followed by 1 or 21 days of forced abstinence prior to assessing preference for the cocaine-paired chamber. Under both conditioning regimens, sham mice exhibited incubation of cocaine CPP after 21 days of abstinence. EcoHIV- infected mice conditioned daily with cocaine showed enhanced cocaine seeking at both abstinence timepoints, whereas infected mice conditioned intermittently showed a reversal of the incubation effect, with higher cocaine seeking after 1 day of abstinence compared to 21 days. Analysis of corticolimbic CX3CL1-CX3CR1 and glutamate receptor expression revealed alterations in medial prefrontal cortex (mPFC) CX3CL1 and nucleus accumbens (NAc) GluN2A receptors that correlated with cocaine seeking following daily cocaine exposure. Moreover, examination of peripheral immune markers showed that the effect of abstinence and EcoHIV infection on these measures depended on the cocaine exposure regimen. Altogether, these results highlight the importance of cocaine abstinence and exposure pattern as critical variables that modulate HIV-associated neuroimmune outcomes and relapse vulnerability.

neuroscience↗

bioRxiv2024

Effects of antiretroviral treatment on central and peripheral immune response in mice with EcoHIV infection

HIV infection is an ongoing global health issue despite increased access to antiretroviral therapy (ART). People living with HIV (PLWH) who are virally suppressed through ART still experience negative health outcomes, including neurocognitive impairment. It is increasingly evident that ART may act independently or in combination with HIV infection to alter immune state, though this is difficult to disentangle in the clinical population. Thus, these experiments used multiplexed chemokine/cytokine arrays to assess peripheral (plasma) and brain (nucleus accumbens; NAc) expression of immune targets in the presence and absence of ART treatment in the EcoHIV mouse model. The findings identify effects of EcoHIV infection and of treatment with bictegravir (B), emtricitabine (F) and tenofovir alafenamide (TAF) on expression of numerous immune targets. In the NAc, this included EcoHIV-induced increases in IL-1 and IL-13 expression and B/F/TAF-induced reductions in KC/CXCL1. In the periphery, EcoHIV suppressed IL-6 and LIF expression, while B/F/TAF reduced IL-12p40 expression. In absence of ART, IBA-1 expression was negatively correlated with CX3CL1 expression in the NAc of EcoHIV-infected mice. These findings identify distinct effects of ART and EcoHIV infection on peripheral and central immune factors and emphasize the need to consider ART effects on neural and immune outcomes.

immunology↗

bioRxiv2024

Caspase-8-mediated CYLD cleavage boots LPS-induced endotoxic shock.

Caspase-8, a pivotal protease intricately involved in various cellular signaling pathways related to cell death and inflammation, has been identified as a contributor to cytokine production during septic shock. However, the mechanisms governing this regulatory role remain enigmatic. In this study, we uncovered that mice harboring a specific mutation in CYLD at its D215 position (CyldD215A/D215A mutant mice), rendering CYLD resistant to caspase8 cleavage, exhibited marked protection against lethal endotoxic shock. Moreover, the removal of Cyld in Caspase8-/-Mlkl-/- mice restored their sensitivity to endotoxic shock, indicating Caspase8 promotes LPS-induced endotoxic shock by cleaving its substrate CYLD and maintaining CYLD stability confers resistance to endotoxic shock. Mechanistically, CYLD was found to catalyze the removal of LUBAC-mediated M1-linked ubiquitination of NF-kB p65 at K301/K303, thereby suppressing the nuclear translocation and activation of p65 for subsequent cytokines production. Notably, the cleaved N-terminal fragment of CYLD (named CP25) is secreted in a TRIF/Caspase8-dependent manner. Moreover, CP25 can be detected in the serum of septic mice, and its levels show a strong correlation with corresponding serum IL-1{beta}, suggesting its potential utility as an inflammatory biomarker. Overall, these findings highlight the significance of CYLD cleavage as a promising therapeutic target and diagnostic marker for endotoxic shock.

immunology↗

bioRxiv2024

Molecular and Cellular Mechanisms of Teneurin Signaling in Synaptic Partner Matching

In developing brains, axons exhibit remarkable precision in selecting synaptic partners among many non-partner cells. Evolutionally conserved teneurins were the first identified transmembrane proteins that instruct synaptic partner matching. However, how intracellular signaling pathways execute teneurins functions is unclear. Here, we use in situ proximity labeling to obtain the intracellular interactome of teneurin (Ten-m) in the Drosophila brain. Genetic interaction studies using quantitative partner matching assays in both olfactory receptor neurons (ORNs) and projection neurons (PNs) reveal a common pathway: Ten-m binds to and negatively regulates a RhoGAP, thus activating the Rac1 small GTPases to promote synaptic partner matching. Developmental analyses with single-axon resolution identify the cellular mechanism of synaptic partner matching: Ten-m signaling promotes local F-actin levels and stabilizes ORN axon branches that contact partner PN dendrites. Combining spatial proteomics and high-resolution phenotypic analyses, this study advanced our understanding of both cellular and molecular mechanisms of synaptic partner matching. HIGHLIGHTSO_LIIn situ spatial proteomics reveal the first intracellular interactome of teneurins C_LIO_LITen-m signals via a RhoGAP and Rac1 GTPase to regulate synaptic partner matching C_LIO_LISingle-axon analyses reveal a stabilization-upon-contact model for partner matching C_LIO_LITen-m signaling promotes F-actin in axon branches contacting partner dendrites C_LI

neuroscience↗

bioRxiv2023

A Day in the Life of Arabidopsis: 24-Hour Time-lapse Single-nucleus Transcriptomics Reveal Cell-type specific Circadian Rhythms

Functional circadian clock is fundamental to the adaptation and survival of organisms. In land plants, the comprehensive profiling of circadian gene expression at the single-cell level is largely unknown partly due to the challenges in obtaining precisely-timed single cells from plant cells embedded within cell walls. To bridge this gap, we employed single-nucleus RNA sequencing (snRNA-seq) on twelve seedling samples collected at 2-hour intervals over a 24-hour day in Arabidopsis, yielding a total of over 130,000 nuclei. From this data, we found that three cell clusters in the shoot share a coherent rhythm, while more than 3,000 genes display cell-type specific rhythmic expression. Only 19 genes are oscillating in more than ten different cell types, and the majority of them are well-documented core oscillators, suggesting the snRNA-seq circadian data could be used to identify key circadian regulators in a broad range of plant systems. Our data provides the first comprehensive resource for plant circadian rhythms at the single-cell level (hosted at https://zhailab.bio.sustech.edu.cn/sc_circadian).

plant biology↗

bioRxiv2023

Duhuo Jisheng Decoction Regulates Intracellular Zinc Homeostasis by Enhancing Autophagy via PTEN/Akt/mTOR to Improve Knee Cartilage Degeneration

BackgroundArticular cartilage degeneration as well as cartilage matrix degradation is one of the key pathological changes in the early stage of knee osteoarthritis (KOA). However, currently, there are limited early prevention and treatment options available. Duhuo Jisheng Decoction (DHJSD) is a formula from Bei Ji Qian jin Yao Fang compiled by Sun Simiao in the Tang Dynasty of China. As a complementary therapy, it is widely used to treat early-stage KOA in China, but its mechanism has not been fully elucidated. ObjectiveThis study is aiming at investigating the potential role and mechanism of DHJSD in protecting cartilage from degradation. MethodsThe mechanism of DHJSD in alleviating OA was explored by gene silencing technology combined with a series of functional experiments in primary rat chondrocytes. Next, 25 wistar rats were used to validate the results obtained in vitro. The PTEN, Akt, mTOR, MMP13, Zn, collagen II, autophagy and apoptosis were determined. ResultsDHJSD reduced the phosphorylation of Akt and mTOR and the expression of zinc, MMP13, Bax and Bcl2. DHJSD increased the level of autophagy and the expression of autophagy proteins LC3 and Beclin1. After silencing PTEN gene, the phosphorylation levels of Akt and mTOR and the effects of Bax, Bcl2, LC3 and Beclin1 were weakened by DHJSD. DHJSD increased the formation of autophagosomes in chondrocytes. Histopathological staining revealed that DHJSD had a protective effect on cartilage. ConclusionDHJSD inhibits Akt/mTOR signaling pathway by targeting PTEN to promote autophagy in chondrocytes, which may be closely to repress the formation of MMP-13 by regulating the level of zinc in chondrocytes.

pharmacology and toxicology↗

bioRxiv2023

Impaired extinction of cocaine seeking in HIV-infected mice is accompanied by peripheral and central immune dysregulation

Substance use disorders (SUDs) are highly comorbid with HIV infection, necessitating an understanding of the interactive effects of drug exposure and HIV. The relationship between progressive HIV infection and cocaine use disorder is likely bidirectional, with cocaine use having direct effects on immune function while HIV infection can alter addiction-related behavior. To better characterized the neurobehavioral and immune consequences of HIV infection and cocaine exposure, this study utilized a humanized mouse model to investigate the outcomes of progressive HIV infection on cocaine-related behaviors in a cocaine conditioned place preference (CPP) model, and the interactive effects of cocaine and HIV infection on peripheral and central nervous system inflammation. HIV infection did not impact the formation of a cocaine CPP, but did result in resistance to extinction of the CPP. No effects of HIV on yohimbine-primed reinstatement or cocaine seeking under conflict were observed. These behavioral alterations were accompanied by immune changes in HIV infected mice, including increased prefrontal cortex astrocyte immunoreactivity and brain-region specific effects on microglia number and reactivity. Peripheral immune system changes were observed in both mouse and human markers. Among other targets, this included HIV-induced reductions in mouse IL-1 and G-CSF and human TNF and cocaine-induced alterations in human TNF and mouse GM-CSF such that cocaine exposure increases both cytokines only in the absence of HIV infection. Together these data provide new insights into the unique neurobehavioral processes underlying HIV infection and cocaine use disorders, and further how they interact to effect immune responses.

neuroscience↗

bioRxiv2023

Rapid and unbiased enrichment of extracellular vesicles via meticulously engineered peptide

Extracellular vesicles (EVs) have garnered significant attention in biomedical applications, particularly as biomarkers and therapeutic agents for cancer diagnosis and treatment. However, the rapid, efficient, and unbiased separation of EVs from complex biological fluids remains a challenge due to their heterogeneity and low abundance concentration in biofluids. Herein, we report a novel approach to reconfigure and modify an artificial insertion peptide for the rapid isolation of EVs in 20 min with [~] 80% recovery. By inserting the peptide into the phospholipid bilayer of EVs, our method enables the unbiased isolation of EVs. Moreover, our approach demonstrates exceptional anti-interference capability and achieves a high purity of EVs comparable to standard ultracentrifugation and other methods. Importantly, we show that the isolated EVs could be directly applied for downstream protein and nucleic acids analyses, including proteomics analysis, exome sequencing analysis, as well as the detection of EGFR and KRAS gene mutation in clinical plasma samples. Our approach offers new possibilities for utilizing EVs in cancer diagnostics through liquid biopsy, as well as in various other biomedical applications.

bioengineering↗

bioRxiv2023

Complex epistatic interactions between ELF3, PRR9, and PRR7 regulates the circadian clock and plant physiology

Circadian clocks are endogenous timekeeping mechanisms that coordinate internal physiological responses with the external environment. EARLY FLOWERING3 (ELF3), PSEUDO RESPONSE REGULATOR (PRR9), and PRR7 are essential components of the plant circadian clock and facilitate entrainment of the clock to internal and external stimuli. Previous studies have highlighted a critical role for ELF3 in repressing the expression of PRR9 and PRR7. However, the functional significance of activity in regulating circadian clock dynamics and plant development is unknown. To explore this regulatory dynamic further, we firstly employed mathematical modelling to simulate the effect of the prr9/prr7 mutation on the elf3 circadian phenotype. These simulations suggested that simultaneous mutations in prr9/prr7 could rescue the elf3 circadian arrythmia. Following these simulations, we generated all Arabidopsis elf3/prr9/prr7 mutant combinations and investigated their circadian and developmental phenotypes. Although these assays could not replicate the results from the mathematical modelling, our results have revealed a complex epistatic relationship between ELF3 and PRR9/7 in regulating different aspects of plant development. ELF3 was essential for hypocotyl development under ambient and warm temperatures, while PRR9 was critical for root thermomorphogenesis. Finally, mutations in prr9 and prr7 rescued the photoperiod insensitive flowering phenotype of the elf3 mutant. Together, our results highlight the importance of investigating the genetic relationship amongst plant circadian genes.

plant biology↗

bioRxiv2023

Structural insights into dual-antagonize mechanism of AB928 on adenosine A2 receptors

The adenosine subfamily G protein-coupled receptors A2AR and A2BR were identified as promising candidates for cancer immunotherapy within recent years. One of the A2AR/A2BR dual antagonist, AB928, has progressed to phase II clinic trial for the treatment of rectal cancer. However, the precise mechanism underlying its dual-antagonistic properties remains elusive. Herein, we report crystal structures of A2AR in complex with AB928 and a selective A2AR antagonist, 2-118. The structures reveal a common binding mode on A2AR, wherein the ligands establish extensive interactions with residues from both the orthosteric pocket and the secondary pocket. Conversely, the cAMP assay together with molecular dynamics simulations conducted on both A2AR and A2BR indicate that the ligands adopt distinct binding modes on A2BR. Detailed analysis of their chemical structures suggests that AB928 can readily adapt to the A2BR pocket, while 2-118 cannot due to its intrinsic differences. This disparity potentially accounts for their divergent inhibitory efficacies between A2BR and A2AR. The findings from this study can serve as valuable structural templates for future development of selective or dual inhibitors targeting A2AR/A2BR in the context of cancer therapy.

cell biology↗

bioRxiv2023

Determinants of species-specific utilization of ACE2 by human and animal coronaviruses

Utilization of human ACE2 allowed several bat coronaviruses (CoVs), including the causative agent of COVID-19, to infect humans either directly or via intermediate hosts. Here, we analyzed the ability of Spike proteins from 24 human or animal CoVs to use ACE2 receptors across nine reservoir, potential intermediate and human hosts. We show that overall SARS-CoV-2 Omicron variants evolved more efficient ACE2 usage but mutation of R493Q in BA.5 Spike disrupts utilization of ACE2 from Greater horseshoe bats. Spikes from most CoVs showed species-specific differences in ACE2 usage, partly due to variations in ACE2 residues 31, 41 or 354. Mutation of T403R allowed the RaTG13 bat CoV Spike to use all ACE2 orthologs analysed for viral entry. Sera from COVID-19 vaccinated individuals neutralized the Spike proteins of a range of bat Sarbecoviruses. Our results define determinants of ACE2 receptor usage of diverse CoVs and suggest that COVID-19 vaccination may protect against future zoonoses of SARS-CoV-related bat viruses. HighlightsO_LIMutation of R493Q in BA.5 Spike disrupts utilization of ACE2 from Greater horseshoe bats C_LIO_LIVariations in ACE2 residues 31, 41 or 354 affect utilization by coronavirus Spike proteins C_LIO_LIResidue R403 in the Spike protein of bat coronavirus allow broad and effective ACE2 usage C_LIO_LISera from COVID-19 vaccinated individuals neutralize Spike proteins of bat Sarbecoviruses C_LI

molecular biology↗