GSTM3 enhances radiosensitivity of nasopharyngeal carcinoma by promoting radiation-induced ferroptosis through USP14/FASN axis and GPX4.

BACKGROUND: Radiotherapy is a critical treatment modality for nasopharyngeal carcinoma (NPC). However, the mechanisms underlying radiation resistance and tumour recurrence in NPC remain incompletely understood. METHODS: Oxidised lipids were assessed through targeted metabolomics. Ferroptosis levels were evaluated using cell viability, clonogenic survival, lipid peroxidation, and transmission electron microscopy. We investigated the biological functions of glutathione S-transferase mu 3 (GSTM3) in cell lines and xenograft tumours. Co-immunoprecipitation, mass spectrometry, and immunofluorescence were conducted to explore the molecular mechanisms involving GSTM3. Immunohistochemistry was performed to investigate the clinical characteristics of GSTM3. RESULTS: Ionising radiation (IR) promoted lipid peroxidation and induced ferroptosis in NPC cells. GSTM3 was upregulated following IR exposure and correlated with IR-induced ferroptosis, enhancing NPC radiosensitivity in vitro and in vivo. Mechanistically, GSTM3 stabilised ubiquitin-specific peptidase 14 (USP14), thereby inhibiting the ubiquitination and subsequent degradation of fatty acid synthase (FASN). Additionally, GSTM3 interacted with glutathione peroxidase 4 (GPX4) and suppressed GPX4 expression. Combining IR treatment with ferroptosis inducers synergistically improved NPC radiosensitivity and suppressed tumour growth. Notably, a decrease in GSTM3 abundance predicted tumour relapse and poor prognosis. CONCLUSIONS: Our findings elucidate the pivotal role of GSTM3 in IR-induced ferroptosis, offering strategies for the treatment of radiation-resistant or recurrent NPC.

MRI-Based Interstitial Fluid Velocity Analysis for Drug Delivery Efficiency Evaluation in Tumor.

There are many flow behaviors in solid tumors, including intravascular, bloodstream, and interstitial convection. Studies have shown that tumor interstitial fluid (TIF) is an important part of tumor microenvironment regulation and affects drug delivery and metabolism between tumor cells. Magnetic resonance imaging (MRI) is suitable for detecting the flow rates of liquids in tissues. Clinical phase contrast PC-MRI technology has been designed to observe the blood flow in large vessels such as arteries and veins; however, it is not sensitive enough to deal with slow flow velocity. Our previously developed vertical plane echo PC-MRI technology, the Velocity Mapping sequence, improved the signal-to-noise ratio (SNR) for measuring slow interstitial fluid rate. In this study, this sequence was used to determine the TIF flow rate in MDA-MB-231 human breast tumor cells used in BALB/c nude male mice. Two different sizes of contrast agents were intravenously injected, and the relationship between their distribution and the TIF flow rate was studied for the first time. Combining the results of clinical scanning showed that small-molecule DTPA-Gd (diethylenetriaminepentaacetic acid-gadolinium) was distributed immediately around the tumor margin after the injection. This distribution was positively correlated to the high flow rate area of the TIF before administration. In contrast, nanoparticles NaGdF4-PEG (polyethylene glycol) entered the tumor and reached their peak at 3 h. Drug distribution was negatively correlated with the high-flow-rate region of the TIF. Investigation of the TIF velocity can help better understand the fluid behavior in tumors and its role in drug delivery.

Transcriptome analysis of Gossypium hirsutum cultivar Zhongzhimian No.2 uncovers the gene regulatory networks involved in defense against Verticillium dahliae.

BACKGROUND: Cotton is globally important crop. Verticillium wilt (VW), caused by Verticillium dahliae, is the most destructive disease in cotton, reducing yield and fiber quality by over 50% of cotton acreage. Breeding resistant cotton cultivars has proven to be an efficient strategy for improving the resistance of cotton to V. dahliae. However, the lack of understanding of the genetic basis of VW resistance may hinder the progress in deploying elite cultivars with proven resistance. RESULTS: We planted the VW-resistant Gossypium hirsutum cultivar Zhongzhimian No.2 (ZZM2) in an artificial greenhouse and disease nursery. ZZM2 cotton was subsequently subjected to transcriptome sequencing after Vd991 inoculation (6, 12, 24, 48, and 72 h post-inoculation). Several differentially expressed genes (DEGs) were identified in response to V. dahliae infection, mainly involved in resistance processes, such as flavonoid and terpenoid quinone biosynthesis, plant hormone signaling, MAPK signaling, phenylpropanoid biosynthesis, and pyruvate metabolism. Compared to the susceptible cultivar Junmian No.1 (J1), oxidoreductase activity and reactive oxygen species (ROS) production were significantly increased in ZZM2. Furthermore, gene silencing of cytochrome c oxidase subunit 1 (COX1), which is involved in the oxidation-reduction process in ZZM2, compromised its resistance to V. dahliae, suggesting that COX1 contributes to VW resistance in ZZM2. CONCLUSIONS: Our data demonstrate that the G. hirsutum cultivar ZZM2 responds to V. dahliae inoculation through resistance-related processes, especially the oxidation-reduction process. This enhances our understanding of the mechanisms regulating the ZZM2 defense against VW.

Low sucrose availability reduces basal spikelet fertility by inducing abscisic acid and jasmonic acid synthesis in wheat.

Within a spike of wheat, the central spikelets usually generate three to four fertile florets, while the basal spikelets generate zero to one fertile floret. The physiological and transcriptional mechanism behind the difference in fertility between the basal and central spikelets is unclear. This study reports a high temporal resolution investigation of transcriptomes, number and morphology of floret primordia, and physiological traits. The W6.5-W7.5 stage was regarded as the boundary to distinguish between fertile and abortive floret primordia; those floret primordia reaching the W6.5-W7.5 stage during the differentiation phase (3-9 d after terminal spikelet stage) usually developed into fertile florets in the next dimorphism phase (12-27 d after terminal spikelet stage), whereas the others aborted. The central spikelets had a greater number of fertile florets than the basal spikelets, which was associated with more floret primordia reaching the W6.5-W7.5 stage. Physiological and transcriptional results demonstrated that the central spikelets had a higher sucrose content and lower abscisic acid (ABA) and jasmonic acid (JA) accumulation than the basal spikelets due to down-regulation of genes involved in ABA and JA synthesis. Collectively, we propose a model in which ABA and JA accumulation is induced under limiting sucrose availability (basal spikelet) through the up-regulation of genes involved in ABA and JA synthesis; this leads to floret primordia in the basal spikelets failing to reach their fertile potential (W6.5-W7.5 stage) during the differentiation phase and then aborting. This fertility repression model may also regulate spikelet fertility in other cereal crops and potentially provides genetic resources to improve spikelet fertility.

Quantitative trait loci detection for three tiller-related traits and the effects on wheat (Triticum aestivum L.) yields.

KEY MESSAGE: A total of 38 putative additive QTLs and 55 pairwise putative epistatic QTLs for tiller-related traits were reported, and the candidate genes underlying qMtn-KJ-5D, a novel major and stable QTL for maximum tiller number, were characterized. Tiller-related traits play an important role in determining the yield potential of wheat. Therefore, it is important to elucidate the genetic basis for tiller number when attempting to use genetic improvement as a tool for enhancing wheat yields. In this study, a quantitative trait locus (QTL) analysis of three tiller-related traits was performed on the recombinant inbred lines (RILs) of a mapping population, referred to as KJ-RILs, that was derived from a cross between the Kenong 9204 (KN9204) and Jing 411 (J411) lines. A total of 38 putative additive QTLs and 55 pairwise putative epistatic QTLs for spike number per plant (SNPP), maximum tiller number (MTN), and ear-bearing tiller rate (EBTR) were detected in eight different environments. Among these QTLs with additive effects, three major and stable QTLs were first documented herein. Almost all but two pairwise epistatic QTLs showed minor interaction effects accounting for no more than 3.0% of the phenotypic variance. The genetic effects of two colocated major and stable QTLs, i.e., qSnpp-KJ-5D.1 and qMtn-KJ-5D, for yield-related traits were characterized. The breeding selection effect of the beneficial allele for the two QTLs was characterized, and its genetic effects on yield-related traits were evaluated. The candidate genes underlying qMtn-KJ-5D were predicted based on multi-omics data, and TraesKN5D01HG00080 was identified as a likely candidate gene. Overall, our results will help elucidate the genetic architecture of tiller-related traits and can be used to develop novel wheat varieties with high yields.

Factors associated with SARS-CoV-2 vaccine hesitancy after stroke: a cross-sectional study.

BACKGROUND: The vaccination status of post-stroke patients, who are at high risk of severe outcomes from Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is a significant concern, yet it remains unclear. We aimed to explore the vaccination status, factors associated with vaccine hesitancy, and adverse effects after vaccination among post-stroke patients. METHODS: This multi-center observational study enrolled hospitalized post-stroke patients from six Chinese hospitals (Oct 1, 2020 - Mar 31, 2021), examining vaccine uptake and self-reported reasons for vaccine hesitancy, utilizing logistic regression to investigate risk factors for vaccine hesitancy, and recording any adverse reactions post-vaccination. RESULTS: Of the total 710 post-stroke patients included in the study, 430 (60.6%) had completed the recommended full-3 dose SARS-CoV-2 vaccination, with 176 (24.8%) remaining unvaccinated. The most common reasons for vaccine hesitancy were concerns about vaccine side effects (41.5%) and impaired mobility (33.9%). Logistic regression identified advanced age (aOR = 1.97, 95%CI: 1.36-2.85, P = 0.001), lower Barthel Index score (aOR = 0.88, 95%CI: 0.82-0.93, P = 0.018), higher Modified Rankin Scale score (aOR = 1.85, 95%CI: 1.32-2.56, P = 0.004), and poorer usual activity level of EuroQol 5-Dimension (aOR = 2.82, 95%CI: 1.51-5.28, P = 0.001) as independent risk factors for vaccine hesitancy. Approximately 14.8% reported minor adverse reactions, mainly pain at the injection site. CONCLUSION: We found that post-stroke patients have insufficient SARS-CoV-2 vaccination rates, with key risk factors for vaccine hesitancy including concerns about side effects, advanced age, and functional impairments. No severe adverse reactions were observed among the vaccinated population.

Diverse regulated cell death modes predict the immune microenvironment and drug sensitivity in lung adenocarcinoma.

Integrated action modes of regulated cell death (RCD) in lung adenocarcinoma (LUAD) have not been comprehensively dissected. Here, we adopted 15 RCD modes, including 1350 related genes, and established RCD signature scores. We found that LUAD patients with high RCD scores had a significantly worse prognosis in all four different cohorts (TCGA, KM-plotter, GSE31210, and GSE30219). Our nomogram established based on the RCD score and clinical characteristics performed well in both the discovery and validation sets. There was a close correlation between the RCD scores and LUAD molecular subtypes identified by unsupervised consensus clustering. Furthermore, we profiled the tumor microenvironment via deconvolution and found significant differences in immune activity, transcription factor activity and molecular pathway enrichment between the RCD-high and RCD-low groups. More importantly, we revealed that the regulation of antigen presentation is the crucial mechanism underlying RCD. In addition, higher RCD scores predict poorer sensitivity to multiple therapeutic drugs, which indicates that RCD scores may serve as a promising predictor of chemotherapy and immunotherapy outcomes. In summary, this work is the first to reveal the internal links between RCD modes, LUAD, and cancer immunity and highlights the necessity of RCD scores in personalizing treatment plans.

High-Sensitivity, Low-Field 19F-MRI Approach Using High Manganese Ferrite Concentrations.

Fluorine-19 (19F) MRI (19F-MRI) is a promising method for quantifying biomedical research and clinical applications without background interference. Nevertheless, dependency on high-field MRI systems limits the applicability of 19F-MRI. Low-field MRI systems are more common than high-field MRI systems. Hence, developing 19F-MRI at low-field MRI devices can promote the 19F-MRI translation in medical diagnosis. The detection sensitivity of fluorine agents is critical in 19F-MRI. Reduction of the 19F spin-lattice relaxation time (T1) enables an improved detection sensitivity while requiring ultrashort echo time (UTE) imaging methods to reduce the negative spin-spin relaxation (T2) decay effect. However, conventional UTE sequences require hardware with high performance. Herein, we introduce the k-space scaling imaging (KSSI) MRI sequence that accomplishes sampling k-space with variable scales to implement hardware-friendly UTE 19F-MRI compatible with low-field MRI systems. We implemented experiments with swine bone, a perfluorooctyl bromide (PFOB) phantom, and one tumor-bearing mouse on two self-customized low-field MRI systems. The swine bone imaging validated the ultrashort TE of KSSI. Under high concentrations of manganese ferrite, a high signal-to-noise ratio was shown in the imaging of a fluorine atom concentration of 658 mM, which indicated high-sensitivity detection of KSSI. Moreover, the KSSI sequence exhibited a 7.1 times signal-to-noise ratio of spin echo sequence on the PFOB phantom imaging with a fluorine atom concentration of 3.29 M. Additionally, the various concentrations of the PFOB phantom imaging revealed quantifiable capacity. Finally, the 1H/19F imaging was implemented with KSSI on one tumor-bearing mouse. This method provides the potential for clinical translation of fluorine probes at low-field MRI systems.

Leveraging circulating microbiome signatures to predict tumor immune microenvironment and prognosis of patients with non-small cell lung cancer.

BACKGROUND: Accumulating evidence supports the significant role of human microbiome in development and therapeutic response of tumors. Circulating microbial DNA is non-invasive and could show a general view of the microbiome of host, making it a promising biomarker for cancers. However, whether circulating microbiome is associated with prognosis of non-small cell lung cancer (NSCLC) and its potential mechanisms on tumor immune microenvironment still remains unknown. METHODS: The blood microbiome data and matching tumor RNA-seq data of TCGA NSCLC patients were obtained from Poore's study and UCSC Xena. Univariate and multivariate Cox regression analysis were used to identify circulating microbiome signatures associated with overall survival (OS) and construct the circulating microbial abundance prognostic scoring (MAPS) model. Nomograms integrating clinical characteristics and circulating MAPS scores were established to predict OS rate of NSCLC patients. Joint analysis of blood microbiome data and matching tumor RNA-seq data was used to deciphered the tumor microenvironment landscape of patients in circulating MAPS-high and MAPS-low groups. Finally, the predictive value of circulating MAPS on the efficacy of immunotherapy and chemotherapy were assessed. RESULTS: A circulating MAPS prediction model consisting of 14 circulating microbes was constructed and had an independent prognostic value for NSCLC. The integration of circulating MAPS into nomograms may improve the prognosis predictive power. Joint analysis revealed potential interactions between prognostic circulating microbiome and tumor immune microenvironment. Especially, intratumor plasma cells and humoral immune response were enriched in circulating MAPS-low group, while intratumor CD4 + Th2 cells and proliferative related pathways were enriched in MAPS-high group. Finally, drug sensitivity analysis indicated the potential of circulating MAPS as a predictor of chemotherapy efficacy. CONCLUSION: A circulating MAPS prediction model was constructed successfully and showed great prognostic value for NSCLC. Our study provides new insights of interactions between microbes, tumors and immunity, and may further contribute to precision medicine for NSCLC.

Association between host nitrogen absorption and root-associated microbial community in field-grown wheat.

Plant roots and rhizosphere soils assemble diverse microbial communities, and these root-associated microbiomes profoundly influence host development. Modern wheat has given rise to numerous cultivars for its wide range of ecological adaptations and commercial uses. Variations in nitrogen uptake by different wheat cultivars are widely observed in production practices. However, little is known about the composition and structure of the root-associated microbiota in different wheat cultivars, and it is not sure whether root-associated microbial communities are relevant in host nitrogen absorption. Therefore, there is an urgent need for systematic assessment of root-associated microbial communities and their association with host nitrogen absorption in field-grown wheat. Here, we investigated the root-associated microbial community composition, structure, and keystone taxa in wheat cultivars with different nitrogen absorption characteristics at different stages and their relationships with edaphic variables and host nitrogen uptake. Our results indicated that cultivar nitrogen absorption characteristics strongly interacted with bacterial and archaeal communities in the roots and edaphic physicochemical factors. The impact of host cultivar identity, developmental stage, and spatial niche on bacterial and archaeal community structure and network complexity increased progressively from rhizosphere soils to roots. The root microbial community had a significant direct effect on plant nitrogen absorption, while plant nitrogen absorption and soil temperature also significantly influenced root microbial community structure. The cultivar with higher nitrogen absorption at the jointing stage tended to cooperate with root microbial community to facilitate their own nitrogen absorption. Our work provides important information for further wheat microbiome manipulation to influence host nitrogen absorption. KEY POINTS: • Wheat cultivar and developmental stage affected microbiome structure and network. • The root microbial community strongly interacted with plant nitrogen absorption. • High nitrogen absorption cultivar tended to cooperate with root microbiome.

Single-molecule counting applied to the study of GPCR oligomerization.

Single-molecule counting techniques enable a precise determination of the intracellular abundance and stoichiometry of proteins and macromolecular complexes. These details are often challenging to quantitatively assess yet are essential for our understanding of cellular function. Consider G-protein-coupled receptors-an expansive class of transmembrane signaling proteins that participate in many vital physiological functions making them a popular target for drug development. While early evidence for the role of oligomerization in receptor signaling came from ensemble biochemical and biophysical assays, innovations in single-molecule measurements are now driving a paradigm shift in our understanding of its relevance. Here, we review recent developments in single-molecule counting with a focus on photobleaching step counting and the emerging technique of quantitative single-molecule localization microscopy-with a particular emphasis on the potential for these techniques to advance our understanding of the role of oligomerization in G-protein-coupled receptor signaling.

Microbial hydrogen "manufactory" for enhanced gas therapy and self-activated immunotherapy via reduced immune escape.

BACKGROUND: As an antioxidant, hydrogen (H2) can selectively react with the highly toxic hydroxyl radical (·OH) in tumor cells to break the balance of reactive oxygen species (ROS) and cause oxidative stress. However, due to the high diffusibility and storage difficulty of hydrogen, it is impossible to achieve long-term release at the tumor site, which highly limited their therapeutic effect. RESULTS: Photosynthetic bacteria (PSB) release a large amount of hydrogen to break the balance of oxidative stress. In addition, as a nontoxic bacterium, PSB could stimulate the immune response and increase the infiltration of CD4+ and CD8+ T cells. More interestingly, we found that hydrogen therapy induced by our live PSB did not lead to the up-regulation of PD-L1 after stimulating the immune response, which could avoid the tumor immune escape. CONCLUSION: Hydrogen-immunotherapy significantly kills tumor cells. We believe that our live microbial hydrogen production system provides a new strategy for cancer hydrogen treatment combining with enhanced immunotherapy without up-regulating PD-L1.

ß-Hydroxybutyrate impairs the release of bovine neutrophil extracellular traps through inhibiting phosphoinositide 3-kinase-mediated nicotinamide adenine dinucleotide phosphate oxidase reactive oxygen species production.

Ketosis in dairy cows often occurs in the peripartal period and is accompanied by immune dysfunction. High concentrations of ß-hydroxybutyrate (BHB) in peripheral blood during ketosis inhibits the release of neutrophil extracellular traps (NET) and contributes to immune dysfunction. However, the mechanisms whereby BHB affects NET release remains unclear. In this study, 5 healthy peripartal dairy cows (within 3 wk postpartum) with serum BHB concentrations <0.6 mM and glucose concentrations >3.5 mM were used as blood donors. Blood samples were collected before feeding, and the isolated polymorphonuclear neutrophils were incubated with 3 mM BHB for different times. Inhibition of Cit-H3 (citrullinated histone 3) protein abundance, a marker of NET activation, in response to BHB was used to determine an optimal incubation time for in vitro experiments. Four hours was selected as the optimal duration of BHB treatment. Phorbol-12-myristate-13-acetate (PMA) was used to induce the release of NET in vitro. The BHB treatment with or without PMA treatment decreased protein abundance of Cit-H3 and PAD4 (arginine deiminase 4) and increased neutrophil elastase. Immunofluorescence and scanning electron microscope analyses revealed that BHB treatment inhibited PMA-induced NET release. The BHB treatment also decreased double strain DNA content in the supernatant, further confirming the inhibitory effect of BHB on NET release. Furthermore, BHB treatment decreased the level of intracellular reactive oxygen species (ROS), phosphorylation level of p47, and protein abundance of Rac2, suggesting that BHB-induced NET inhibition may have been caused by decreased NADPH oxidase-derived ROS. The phosphorylation level of phosphoinositide 3-kinase (PI3K), an important upstream regulator of NADPH oxidase, was attenuated by BHB treatment. To confirm the involvement of PI3K signaling pathway in BHB-induced NET inhibition, 740Y-P, a potent activator of PI3K signaling pathway, was used. Data indicated that 740Y-P relieved the inhibitory effects of BHB on ROS production and NADPH oxidase activation. Importantly, as revealed by immunofluorescence and scanning electron microscopy analyses, 740Y-P also dampened the inhibitory effect of BHB on NET release and the protein abundance of Cit-H3 and PAD4. Overall, the present study revealed that high concentration of BHB impairs NET release through inhibiting PI3K-mediated NADPH oxidase ROS production. These findings help partly explain the immune dysfunction in cows experiencing negative energy balance or ketosis in early lactation.

Epstein-Barr virus (EBV) encoded microRNA BART8-3p drives radioresistance-associated metastasis in nasopharyngeal carcinoma.

Radiotherapy plays an important role in the treatment of nasopharyngeal carcinoma (NPC), however, 20% of patients with NPC exhibit unusual radioresistance. Patients with radioresistance are at risk of recurrence, so it is imperative to explore the mechanism of resistance to radiotherapy. In the past, studies on the mechanism of radioresistance have been restricted to DNA damage and related cell cycle remodeling or apoptosis. So far, no studies have explored the relationship between radioresistance and metastasis. Through the analysis of clinical samples, we observed that the metastasis rate of recurrent NPC was much higher than that of primary patients. In vitro and in vivo experiments showed that NPC cells with acquired radioresistance exhibited a stronger ability for invasion and metastasis. Mechanistically, we found that the Epstein-Barr virus (EBV)-encoded miRNA BART8-3p was increased in patients with NPC, and its expression was positively correlated with adverse prognostic factors, such as radioresistance. Besides this, miR-BART8-3p promoted the epithelial-mesenchymal transition, invasion, and metastasis of radioresistant NPC cells by targeting and inhibiting their PAG1 host gene. These findings suggested a novel role for EBV-miR-BART8-3p in promoting NPC radioresistance-associated metastasis and highlighted its potential value as a prognostic indicator or therapeutic target.

Study protocol for an open-label, single-arm, phase Ib/II study of combination of toripalimab, nab-paclitaxel, and gemcitabine as the first-line treatment for patients with unresectable pancreatic ductal adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a fatal disease with a dismal response to single-use of immune checkpoint inhibitors (ICIs). ICIs combined with systemic therapy has shown efficacy and safety in various solid tumors. Nab-paclitaxel and gemcitabine (AG), as the standard first-line treatment for advanced PDAC, has been widely used in recent years. The combination of ICIs and AG chemotherapy appears to be a promising option in the treatment of PDAC. METHODS: This is an open-label, single-arm, and single-center phase Ib/II trial. The enrolled subjects are the unresectable (locally advanced or metastatic) PDAC patients without previous systemic treatments. All subjects receive an intravenous injection of gemcitabine 1000 mg/m2 and nab-paclitaxel 125 mg/m2 on day 1 and day 8, along with toripalimab 240 mg at day 1 every 3 weeks. The subjects may discontinue the treatment because of progression disease (PD), intolerable toxicities, requirements of patients or researchers. For local advanced patients who are evaluated as partial response (PR), surgeons need to assess the surgical possibility. The primary objective of this trial is to evaluate the safety and overall survival (OS) of this combination therapy; and the secondary objective is related to the assessment of objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and the rate of resection or R0 resection after receiving toripalimab plus AG treatment. Besides, we expect to identify the predictive biomarkers (such as MMR protein and PD-L1 expression, the number of TILs, the small RNA of EBV and so on) and explore the correlation between these biomarkers and tumor response to this combined regimen. DISCUSSION: This trial is the first attempt to evaluate the efficacy and safety of the combination of toripalimab plus AG chemotherapy as a first-line treatment for unresectable PDAC patients. The results of this phase Ib/II study will provide preliminary evidence for further assessment of this combined therapeutic regimen for unresectable PDAC patients. TRIAL REGISTRATION: Trial registration: ChiCTR ( ChiCTR2000032293 ). Registered 25 April 2020 - Retrospectively registered.

Asymmetric Total Syntheses of Kopsia Indole Alkaloids.

The asymmetric total syntheses of a group of structurally complex Kopsia alkaloids, (-)-kopsine, (-)-isokopsine, (+)-methyl chanofruticosinate, (-)-fruticosine, and (-)-kopsanone, has been achieved. The key strategies for the construction of the molecular complexity in the targets included an asymmetric Tsuji-Trost rearrangement to set the first quaternary carbon center at C20, an intramolecular cyclopropanation by diazo decomposition to install the second and third quaternary carbon centers at C2 and C7, respectively, and a SmI2 -promoted acyloin condensation to assemble the isokopsine core. A radical decarboxylation of an isokopsine-type intermediate results in a thermodynamic partial rearrangement to give N-decarbomethoxyisokopsine and N-decarbomethoxykopsine, two key intermediates for the syntheses of Kopsia alkaloids with different subtype core structures.

Diffusion and Oligomerization States of the Muscarinic M1 Receptor in Live Cells─The Impact of Ligands and Membrane Disruptors.

G protein-coupled receptors (GPCRs) are a major gateway to cellular signaling, which respond to ligands binding at extracellular sites through allosteric conformational changes that modulate their interactions with G proteins and arrestins at intracellular sites. High-resolution structures in different ligand states, together with spectroscopic studies and molecular dynamics simulations, have revealed a rich conformational landscape of GPCRs. However, their supramolecular structure and spatiotemporal distribution is also thought to play a significant role in receptor activation and signaling bias within the native cell membrane environment. Here, we applied single-molecule fluorescence techniques, including single-particle tracking, single-molecule photobleaching, and fluorescence correlation spectroscopy, to characterize the diffusion and oligomerization behavior of the muscarinic M1 receptor (M1R) in live cells. Control samples included the monomeric protein CD86 and fixed cells, and experiments performed in the presence of different orthosteric M1R ligands and of several compounds known to change the fluidity and organization of the lipid bilayer. M1 receptors exhibit Brownian diffusion characterized by three diffusion constants: confined/immobile (∼0.01 µm2/s), slow (∼0.04 µm2/s), and fast (∼0.14 µm2/s), whose populations were found to be modulated by both orthosteric ligands and membrane disruptors. The lipid raft disruptor C6 ceramide led to significant changes for CD86, while the diffusion of M1R remained unchanged, indicating that M1 receptors do not partition in lipid rafts. The extent of receptor oligomerization was found to be promoted by increasing the level of expression and the binding of orthosteric ligands; in particular, the agonist carbachol elicited a large increase in the fraction of M1R oligomers. This study provides new insights into the balance between conformational and environmental factors that define the movement and oligomerization states of GPCRs in live cells under close-to-native conditions.

Reversing Immune Checkpoint Inhibitor-Associated Cardiotoxicity via Bioorthogonal Metabolic Engineering-Driven Extracellular Vesicle Redirecting.

The cardiotoxicity induced by immune checkpoint inhibitors (ICIs) is associated with high mortality rates. T cells play an important role in ICI-induced cardiac injury. The inhibition of local T-cell activity is considered an effective strategy for alleviating ICI-related cardiotoxicity. Tumor-derived extracellular vesicles (EVs) contribute to immunosuppression via PD-L1 overexpression. In this study, a bioorthogonal metabolic engineering-driven EV redirecting (Biomeder) strategy for in situ engineered EVs with myocardial-targeting peptides is developed. Accumulated tumor-derived EV (TuEVs) reverses the immune environment in the heart by increasing PD-L1 levels in cardiomyocytes and/or by directly inhibiting T-cell activity. More importantly, it is found that the redirection of TuEVs further disrupts immunosuppression in tumors, which facilitates anti-tumor activity. Thus, redirecting TuEVs to the heart simultaneously enhances the antitumor efficacy and safety of ICI-based therapy. Furthermore, the Biomeder strategy is successfully expanded to prevent ICI-induced type 1 diabetes. This Biomeder technique is a universal method for the treatment of various ICI-related adverse events.

Bidirectional transitions of sarcopenia states in older adults: The longitudinal evidence from CHARLS.

BACKGROUND: Sarcopenia, the age-related loss of muscle mass and function, brings multiple adverse outcomes including disability and death. Several sarcopenia consensuses have newly introduced the premorbid concept of possible sarcopenia and recommended early lifestyle interventions. Bidirectional transitions of premorbid states have been revealed in several chronic diseases yet not clarified in sarcopenia. This study aims to investigate the underlying transition patterns of sarcopenia states. METHODS: The study utilized three waves of data from a nationally representative survey, the China Health and Retirement Longitudinal Study (CHARLS), and included community-dwelling individuals aged 60 years and older with at least two sarcopenia states assessments based on the Asian Working Group for Sarcopenia criteria 2019 (AWGS2019) between 2011 and 2015. The estimated transition intensity and probability between non-sarcopenia, possible sarcopenia, sarcopenia, and death were investigated using multi-stage Markov (MSM) models. RESULTS: The study comprised 4395 individuals (49.2% female, median age 67 years) with a total of 10 778 records of sarcopenia state assessment, and the mean follow-up period was 3.29 years. A total of 24.5% of individuals with a current state of possible sarcopenia returned to non-sarcopenia, 60.3% remained possible sarcopenia, 6.7% progressed to sarcopenia, and 8.5% died by the next follow-up. The transition intensity of recovery to non-sarcopenia (0.252, 95% CI 0.231-0.275) was 2.8 times greater than the deterioration to sarcopenia (0.090, 95% CI 0.080-0.100) for individuals with possible sarcopenia. For individuals with possible sarcopenia, the estimated probabilities of recovering to non-sarcopenia, progressing to sarcopenia, and transitioning to death within a 1-year observation were 0.181, 0.066, and 0.035, respectively. For individuals with sarcopenia, the estimated probabilities of recovering to non-sarcopenia, recovering to possible sarcopenia, and transitioning to death within 1-year observation were 0.016, 0.125, and 0.075, respectively. In covariables analysis, age, sex, body mass index, physical function impairment, smoking, hypertension, and diabetes are important factors influencing bidirectional transitions. CONCLUSIONS: The findings highlight the bidirectional transitions of sarcopenia states among older adults and reveal a notable proportion of possible sarcopenia show potential for recovery in the natural course. Screening and intensifying interventions based on risk factors may facilitate a recovery transition.

Endoplasmic Reticulum Stress Potentiates the Immunosuppressive Microenvironment in Hepatocellular Carcinoma by Promoting the Release of SNHG6-Enriched Small Extracellular Vesicles.

Endoplasmic reticulum (ER) stress leads to hepatocellular carcinoma (HCC) progression. Small extracellular vesicles (sEV) play a crucial role in modulating the tumor microenvironment (TME) by influencing cellular communication and immune responses. However, it is unclear whether ER stress modulates the TME through sEVs. In the current study, we investigated the effects and underlying mechanisms of ER stress on the HCC TME. In vivo and in vitro experiments showed that overactivated ER stress was a salient attribute of the immunosuppressive HCC TME. This was caused by the ATF4-promoted release of small nucleolar RNA host gene 6 (SNHG6)-carrying sEVs, which attenuated T cell-mediated immune responses. Overall, SNHG6 modulated the immunosuppressive TME and aggravated ER stress. Meanwhile, targeting SNHG6 facilitated M1-like macrophage and CD8+ T-cell infiltration and decreased the proportion of M2-like macrophages. In addition, SNHG6 knockdown enhanced anti-PD1 immunotherapeutic efficacy. Moreover, in HCC patients, overexpression of SNHG6 was associated with a lack of response to anti-PD1 therapy and poor prognosis, whereas low SNHG6 expression was associated with improved therapeutic efficacy and prognoses. These data indicate that a correlation exists among ER stress, sEVs, immunosuppressive HCC TME, and immunotherapeutic efficacy. Hence, SNHG6-targeted therapy may represent an effective strategy for patients with HCC.