Revealing roles of S-layer protein (SlpA) in Clostridioides difficile pathogenicity by generating the first slpA gene deletion mutant.

Clostridioides difficile infection (CDI) with high morbidity and high mortality is an urgent threat to public health, and C. difficile pathogenesis studies are eagerly required for CDI therapy. The major surface layer protein, SlpA, was supposed to play a key role in C. difficile pathogenesis; however, a lack of isogenic slpA mutants has greatly hampered analysis of SlpA functions. In this study, the whole slpA gene was successfully deleted for the first time via CRISPR-Cas9 system. Deletion of slpA in C. difficile resulted in smaller, smother-edged colonies, shorter bacterial cell size, and aggregation in suspension. For life cycle, the mutant demonstrated lower growth (changes of optical density at 600 nm, OD600) but higher cell density (colony-forming unit, CFU), decreased toxins production, and inhibited sporulation. Moreover, the mutant was more impaired in motility, more sensitive to vancomycin and Triton X-100-induced autolysis, releasing more lactate dehydrogenase. In addition, SlpA deficiency led to robust biofilm formation but weak adhesion to human host cells.IMPORTANCEClostridioides difficile infection (CDI) has been the most common hospital-acquired infection, with a high rate of antibiotic resistance and recurrence incidences, become a debilitating public health threat. It is urgently needed to study C. difficile pathogenesis for developing efficient strategies as CDI therapy. SlpA was indicated to play a key role in C. difficile pathogenesis. However, analysis of SlpA functions was hampered due to lack of isogenic slpA mutants. Surprisingly, the first slpA deletion C. difficile strain was generated in this study via CRISPR-Cas9, further negating the previous thought about slpA being essential. Results in this study will provide direct proof for roles of SlpA in C. difficile pathogenesis, which will facilitate future investigations for new targets as vaccines, new therapeutic agents, and intervention strategies in combating CDI.

Midbrain dopaminergic degeneration differentially modulates primary motor cortex activity and motor behavior in hemi-parkinsonian rats.

Parkinson's disease (PD) is marked by degeneration in the nigrostriatal dopaminergic pathway, affecting motor control via complex changes in the cortico-basal ganglia-thalamic motor network, including the primary motor cortex (M1). The modulation of M1 neuronal activity by dopaminergic inputs, particularly from the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc), plays a crucial role in PD pathophysiology. This study investigates how nigrostriatal dopaminergic degeneration influences M1 neuronal activity in rats using in vivo calcium imaging. Histological analysis confirmed dopaminergic lesion severity, with high lesion level rats showing significant motor deficits. Levodopa treatment improved fine motor abilities, particularly in high lesion level rats. Analysis of M1 calcium signals based on dopaminergic lesion severity revealed distinct M1 activity patterns. Animals with low dopaminergic lesion showed increased calcium events, while high lesion level rats exhibited decreased activity, partially restored by levodopa. These findings suggest that M1 activity is more sensitive to transient fluctuations in dopaminergic transmission, rather than to chronic high or low dopaminergic signaling. This study underscores the complex interplay between dopaminergic signaling and M1 neuronal activity in PD symptoms development. Further research integrating behavioral and calcium imaging data can elucidate mechanisms underlying motor deficits and therapeutic responses in PD.

Dual hybrid frameworks combining graph convolutional network with decoding for covering location problem.

The Covering Location Problem (CLP) is widely used for the efficient facility distribution. However, existing algorithms for this problem suffer from long computation times or suboptimal solutions. To address this, we propose two methods based on graph convolutional networks (GCN) to solve two types of covering location problems: the location set covering problem and the maximum covering location problem. The first method, GCN-Greedy, is a supervised algorithm that synergized with the Greedy algorithm as decoder. It designs a specialized loss function to train the model, tailored to the characteristics of the two covering location problems. The second method, reinforcement learning based on GCN with auto-regressive decoder (GCN-AR-RL), represents a reinforcement learning framework that integrates a GCN encoder with an auto-regressive decoder. The experimental results of these models demonstrate the remarkable accuracy and performance advantages. Additionally, we apply these two models to the realistic dataset and achieve good performance.

Incidence of cardiovascular mortality among head and neck cancer patients.

BACKGROUND: While treatment advancements have prolonged the lives of patients with head and neck cancer, the subgroups of these patients at higher risk for cardiovascular disease (CVD) mortality remain unclear. METHODS: We analyzed data from the Surveillance, Epidemiology, and End Results (SEER) database for patients diagnosed with head and neck cancer from 2000 to 2019. We compared their CVD mortality against the general US population using standardized mortality ratios (SMRs). RESULTS: Our analysis included 474,366 patients, identifying that 14% of deaths were due to CVD, with an SMR of 1.19. Notably, patients under the age of 39 had a CVD SMR increase of over 100-fold. Those with distant tumor stages showed the highest CVD SMR of 1.52 (95% CI 1.50-1.54). An upward trend in SMR to 2.53 (95% CI 2.51-2.56) was observed from 2011 to 2019. Within the initial 5-year post-diagnosis, the SMR for CVD was 3.17 (95% CI 3.14-3.20), which exceeded the general population's rates but declined in the 5-20-year range after diagnosis. Patients who did not any therapy had the greatest CVD SMR of 2.26 (95% CI 2.24-2.28). Hypopharyngeal cancer patients exhibited the highest CVD SMR of 1.54 (95% CI 1.52-1.56). CONCLUSIONS: The study highlights that head and neck cancer patients, especially younger individuals and those with advanced disease stages, face substantial CVD mortality risks. The CVD SMR peaks within 5 years following diagnosis. Patients abstaining from treatment bear the highest risk of CVD mortality. Cardioprotective measures should be considered critical for this patient population.

Identification of 1,3,4-Thiadiazolyl-Containing Thiazolidine-2,4-dione Derivatives as Novel PTP1B Inhibitors with Antidiabetic Activity.

Forty-one 1,3,4-thiadiazolyl-containing thiazolidine-2,4-dione derivatives (MY1-41) were designed and synthesized as protein tyrosine phosphatase 1B (PTP1B) inhibitors with activity against diabetes mellitus (DM). All synthesized compounds (MY1-41) presented potential PTP1B inhibitory activities, with half-maximal inhibitory concentration (IC50) values ranging from 0.41 ± 0.05 to 4.68 ± 0.61 µM, compared with that of the positive control lithocholic acid (IC50 = 9.62 ± 0.14 µM). The most potent compound, MY17 (IC50 = 0.41 ± 0.05 µM), was a reversible, noncompetitive inhibitor of PTP1B. Circular dichroism spectroscopy and molecular docking were employed to analyze the binding interaction between MY17 and PTP1B. In HepG2 cells, MY17 treatment could alleviate palmitic acid (PA)-induced insulin resistance by upregulating the expression of phosphorylated insulin receptor substrate and protein kinase B. In vivo, oral administration of MY17 could reduce the fasting blood glucose level and improve glucose tolerance and dyslipidemia in mice suffering from DM.

Different biomarker ratios in peripheral blood have limited value in diagnosing periprosthetic joint infection after total joint arthroplasty: a single-center, retrospective study.

BACKGROUND: Periprosthetic joint infection (PJI) is a severe complication that can occur after total joint arthroplasty (TJA). The timely and accurate diagnosis of PJI is the key to treatment. This study investigated the diagnostic value of platelet to lymphocyte ratio (PLR), platelet count to mean platelet volume ratio (PVR), neutrophil to lymphocyte ratio (NLR) and monocyte to lymphocyte ratio (MLR) in PJI after total knee arthroplasty (TKA) and total hip arthroplasty (THA). METHODS: We performed a retrospective analysis of the patients who underwent revision hip or knee arthroplasty at our Institute between June 2015 and June 2020. Of the 187 patients reviewed, 168 were included in the study. According to the diagnostic criteria of the Musculoskeletal Infection Society (MSIS), 58 patients were in the PJI group, and 110 patients were in the aseptic loosening (AL) group. We recorded and compared the preoperative peripheral blood white blood cell (WBC) count, platelet count (PLT), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), PLR, PVR, NLR, and MLR in both groups. The diagnostic performance of the WBC, PLT, PLR, PVR, NLR, and MLR individually and in combination with the ESR and CRP for PJI diagnosis was evaluated by receiver operating characteristic (ROC) curves, and the sensitivity, specificity, positive predictive value, and negative predictive value were calculated. RESULTS: Compared to those in the AL group, the mean WBC, PLT, ESR, CRP, PLR, PVR, NLR, and MLR in the peripheral blood of the PJI group were significantly greater (P < 0.05). The analysis of the ROC curve revealed that the ESR, CRP, PLR, PVR, NLR, and MLR in peripheral blood had moderate effectiveness in diagnosing PJI, with area under the curve (AUC) values of 0.760 (95% CI: 0.688-0.823), 0.758 (95% CI: 0.687-0.821), 0.714 (95% CI: 0.639-0.781), 0.709 (95% CI: 0.634-0.777), 0.723 (95% CI: 0.649-0.789), and 0.728 (95% CI: 0.654-0.793), respectively. Conversely, the WBC and PLT counts demonstrated poor diagnostic value for PJI, with AUC values of 0.578 (95% CI: 0.499-0.653) and 0.694 (95% CI: 0.619-0.763), respectively. The results of the prediction model calculations revealed that the combined AUC of the WBC, PLT, ESR, CRP, PLR, PVR, NLR, and MLR was the highest at 0.853 (95% CI, 0.790-0.909), indicating good value in the diagnosis of PJI, with a sensitivity of 82.8% and a specificity of 72.7%. Moreover, the novel composite of parameters improved the accuracy and reliability in diagnosing PJI compared to the traditional biomarkers ESR and CRP (P = 0.015). CONCLUSION: Our study suggested that the diagnostic value of the peripheral blood biomarkers PLR, PVR, NLR, and MLR for diagnosing PJI is limited and not superior to that of the ESR or CRP. However, when the WBC, PLT, ESR, CRP, PLR, PVR, NLR, and MLR are combined, the diagnostic performance of PJI in TJA patients can be improved.

Transcriptome differential expression analysis of defoliation of two different lemon varieties.

'Allen Eureka' is a bud variety of Eureka lemon with excellent fruiting traits. However, it suffers from severe winter defoliation that leads to a large loss of organic nutrients and seriously affects the tree's growth and development as well as the yield of the following year, and the mechanism of its response to defoliation is still unclear. In order to investigate the molecular regulatory mechanisms of different leaf abscission periods in lemon, two lemon cultivars ('Allen Eureka' and 'Yunning No. 1') with different defoliation traits were used as materials. The petiole abscission zone (AZ) was collected at three different defoliation stages, namely, the pre-defoliation stage (CQ), the mid-defoliation stage (CZ), and the post-defoliation stage (CH). Transcriptome sequencing was performed to analyze the gene expression differences between these two cultivars. A total of 898, 4,856, and 3,126 differentially expressed genes (DEGs) were obtained in CQ, CZ, and CH, respectively, and the number of DEGs in CZ was the largest. GO analysis revealed that the DEGs between the two cultivars were mainly enriched in processes related to oxidoreductase, hydrolase, DNA binding transcription factor, and transcription regulator activity in the defoliation stages. KEGG analysis showed that the DEGs were concentrated in CZ and involved plant hormone signal transduction, phenylpropanoid biosynthesis, glutathione metabolism, and alpha-linolenic acid metabolism. The expression trends of some DEGs suggested their roles in regulating defoliation in lemon. Eight gene families were obtained by combining DEG clustering analysis and weighted gene co-expression network analysis (WGCNA), including ß-glucosidase, AUX/IAA, SAUR, GH3, POD, and WRKY, suggesting that these genes may be involved in the regulation of lemon leaf abscission. The above conclusions enrich the research related to lemon leaf abscission and provide reliable data for the screening of lemon defoliation candidate genes and analysis of defoliation pathways.

Microglial SCAP deficiency protects against diabetes-associated cognitive impairment through inhibiting NLRP3 inflammasome-mediated neuroinflammation.

Hyperglycemia-induced pathological microglial responses and subsequent neuronal damage are notable characteristics of diabetes-associated cognitive impairment (DACI). Cholesterol accumulation in the brain is a prevalent consequence of diabetes mellitus (DM), exacerbating pathological microglial responses. Regarding disordered glucose and lipid metabolism, the Sterol Regulatory Element-Binding Protein (SREBP) cleavage-activating protein (SCAP), a cholesterol sensor, exhibits increased expression and abnormal translocation from the endoplasmic reticulum to the Golgi, amplifying the inflammatory response. Therefore, we hypothesized that overexpression of microglia-SCAP and cholesterol accumulation in DM mice could induce pathological microglial responses associated with DACI. Our type 2 DM mice model presented an abnormal increase in microglial SCAP expression. The functional loss of microglia-specific SCAP in DM mice improved cognitive impairment, neuronal synaptic plasticity deficits, and abnormal microglial responses. Mechanistically, the accumulated SCAP directly bound to and enhanced the activation of the microglial-specific inflammatory amplifier, NLRP3 inflammasome, in Golgi, thereby increasing pathological microglial responses and promoting neuronal damage. These findings indicate an important regulatory axis of microglial responses from SCAP to the NLRP3 inflammasome pathway in microglia. These underscore the crosstalk between cholesterol disorders and pathological microglial responses, offering a promising avenue for pharmaceutical interventions in DACI.

Transcriptome differential expression analysis of defoliation in different lemon varieties under drought treatment.

'Allen Eureka' is a bud variety of Eureka lemon with excellent fruiting traits, but severe winter defoliation affects the following year's yield, and the response mechanism of lemon defoliation is currently unknown. Two lemon cultivars ('Allen Eureka' and 'Yunning No. 1') with different defoliation traits were used as materials to investigate the molecular regulatory mechanisms of different leaf abscission periods in lemons. The petiole abscission zone was collected at three different defoliation stages, namely, the predefoliation stage (k15), the middefoliation stage (k30), and the postdefoliation stage (k45). Transcriptome sequencing was performed to analyze the gene expression differences between these two cultivars. A total of 1141, 2695, and 1433 differentially expressed genes (DEGs) were obtained in k15, k30, and k45, respectively, and the number of DEGs in k30 was the largest. GO analysis revealed that the DEGs between the two cultivars were mainly enriched in processes related to hydrolase activity, chitinase activity, oxidoreductase activity, and transcription regulator activity in the defoliation stages. KEGG analysis showed that the DEGs were concentrated in k30, which involved plant hormone signal transduction, phenylpropanoid biosynthesis, and biosynthesis of amino acids. The expression trends of some DEGs suggested their roles in regulating defoliation in Lemon. Seven genes were obtained by WGCNA, including sorbitol dehydrogenase (CL9G068822012_alt, CL9G068820012_alt, CL9G068818012_alt), abscisic acid 8'-hydroxylase (CL8G064053012_alt, CL8G064054012_alt), and asparagine synthetase (CL8G065162012_alt, CL8G065151012_alt), suggesting that these genes may be involved in the regulation of lemon leaf abscission.

Catalytic Asymmetric Synthesis of Vicinal Quaternary Stereocenters Enabled by Alkylation of α,α-Disubstituted Aldehydes with 3-Bromooxindoles.

An organocatalytic enantioselective alkylation of α,α-disubstituted aldehydes with 3-bromooxindoles is reported. Enantioenriched oxindoles with vicinal quaternary stereocenters are accessed by an asymmetric conjugate addition process of branched aldehydes with o-azaxylylene intermediates (indol-2-ones). Key to the success of highly diastereo- and enantioselective transformations is the combined use of a triphenylsilyl-protected ß-amino alcohol catalyst derived from the spiropyrrolidine scaffold and 3,5-dinitrobenzoic acid. This study also presents a rare example of aldehyde alkylation with the formation of consecutive quaternary stereocenters.

Physical exercise and hypertension: A retrospective study in southern Sichuan.

This study aimed to scrutinize the relationship between physical exercise and hypertension, taking into account multiple variables such as age, body mass index (BMI), family history, smoking, and alcohol consumption in the Southern Sichuan population, China, using a retrospective approach based on hospital record data. This retrospective study analyzed data from 946 participants obtained from a hospital electronic medical record system. The data included information regarding participants' lifestyle factors, family history, and a clinical diagnosis of hypertension. Univariate and multivariate logistic regression models were employed to identify the association between lifestyle factors and hypertension. The study found a hypertension prevalence of 38.5% in the analyzed population. Multivariate analyses identified significant factors associated with hypertension as age (odds ratio [OR]: 1.045, 95% confidence interval [CI]: 1.036-1.054), BMI (OR: 1.107, 95% CI: 1.084-1.132), smoking (OR: 2.299, 95% CI: 1.674-3.157), alcohol consumption (OR: 0.644, 95% CI: 0.478-0.867), and physical exercise (OR: 0.682, 95% CI: 0.506-0.920). Findings from this hospital record-based retrospective study reinforce the multifactorial nature of hypertension. They highlight the significance of physical exercise, along with maintaining optimal BMI and encouraging healthy habits like nonsmoking and moderate alcohol consumption in hypertension prevention. Our findings also underscore the need for future prospective studies to establish causality and explore the generalizability of these results beyond the Southern Sichuan population.

The Perceval Sutureless Bioprosthetic Aortic Valve: Evolution of Surgical Valve Technology.

OBJECTIVE: The surgical treatment of aortic stenosis continues to evolve, and sutureless aortic valve replacement (SUAVR) is an emerging technology. With the Perceval S (Corcym, London, UK) as the only true sutureless valve on the market, the objective of this review is to analyze the current literature on Perceval S. Focusing on valve design and deployment as well as applications of the technology for challenging pathology, clinical outcomes are assessed, including a comparison with transcatheter AVR (TAVR). METHODS: PubMed and MEDLINE were searched by 3 authors for studies analyzing SUAVR from inception to May 19, 2023. RESULTS: SUAVR facilitates minimally invasive surgery and offers an alternative strategy for patients with small aortic annuli. It also has a time-saving advantage for patients who require complex operations. SUAVR results in excellent long-term morbidity, mortality, durability, and hemodynamic function. In comparison with conventional surgical AVR (SAVR), SUAVR does have a greater risk of postoperative pacemaker implantation; however, increasing user experience and refinements in implantation technique have contributed to reductions in this outcome. SUAVR results in morbidity and mortality that is similar to rapid-deployment AVR. Midterm outcomes are superior to TAVR; however, further robust investigation into all of these comparisons is ultimately necessary. CONCLUSIONS: SUAVR bridges the gap in technology between SAVR and TAVR. The application of this exciting technology will undoubtedly grow in the coming years, during which additional investigation is paramount to optimize preoperative planning, valve deployment, and reintervention strategies.

Assessment of the Effect of the Main Grain-Producing Areas Policy on China's Food Security.

Food provided a material foundation for the development of human society and was an important cornerstone for ensuring national security. The Chinese government has always attached great importance to food security, which is not only related to economic development and social stability but also to national security and self-reliance. As the core region for grain production and the supply of staple food in China, the major grain-producing areas account for 78.25% of the total national grain output, truly earning the title of China's "granary". Considering the establishment of 13 major grain-producing regions across the country in 2004 as a quasi-natural experiment, the impact of policies in major grain-producing regions on ensuring national food security is examined using a difference-in-differences method based on inter-provincial panel data for 30 provinces across the country from 1997 to 2020, and the mechanisms of their effects are further analyzed. The findings show that (1) the main producing-areas policy has a significant driving effect on China's food security, with an average annual increase of 0.0351 units in the food-security index, and the impact is expanding year by year. (2) The policy of the main grain-producing provinces mainly plays a role in guaranteeing food security by expanding the scale of grain cultivation and the scale of family land management in the main grain-producing provinces, and the scale effect of grain cultivation has a more significant impact. Further adjusting and improving the policy of the main grain-producing areas and expanding the scale-driven effect of this policy are of great significance for transforming agricultural production methods and realizing a strong agricultural country.

Safety and efficacy of dexmedetomidine vs. midazolam in complex gastrointestinal endoscopy: A systematic review and meta-analysis.

OBJECTIVE: This study aims to perform a meta-analysis to evaluate the safety and efficacy of dexmedetomidine versus midazolam for complex digestive endoscopy procedures, with the goal of offering comprehensive clinical evidence. METHODS: Following predefined inclusion criteria, five databases were systematically searched, with a focus on identifying randomized controlled trials (RCTs) that compared the administration of dexmedetomidine and midazolam during complex digestive endoscopy procedures. The statistical software Stata 15.1 was employed for meticulous data analysis. RESULTS: Sixteen RCTs were encompassed, involving a total of 1218 patients. In comparison to the midazolam group, dexmedetomidine administration was associated with a reduced risk of respiratory depression (RR=0.25, 95 %CI: 0.11-0.56) and hypoxemia (RR=0.22, 95 %CI: 0.12-0.39). Additionally, the dexmedetomidine group exhibited lower incidence rates of choking (RR=0.27, 95 %CI: 0.16-0.47), physical movement (RR=0.16, 95 %CI: 0.09-0.27), and postoperative nausea and vomiting (RR=0.56,95 %CI: 0.34-0.92). Patients and endoscopists in the dexmedetomidine group reported higher levels of satisfaction (patient satisfaction: SMD=0.73, 95 %CI: 0.26-1.21; endoscopist satisfaction: SMD=0.84, 95 %CI: 0.24-1.44). The incidence of hypotension and anesthesia recovery time did not significantly differ between the two groups (hypotension: RR=1.73,95 %CI:0.94-3.20; anesthesia recovery time: SMD=0.02, 95 %Cl: 0.44-0.49). It is noteworthy that the administration of dexmedetomidine was associated with a significant increase in the incidence of bradycardia in patients. CONCLUSION: Compared to midazolam, dexmedetomidine exhibits a favorable safety profile for use in complex gastrointestinal endoscopy by significantly reducing the risk of respiratory depression and hypoxemia. Despite this, dexmedetomidine is associated with a higher incidence of bradycardia. These findings underscore the need for further research through larger, multi-center studies to thoroughly investigate dexmedetomidine's safety and efficacy.

Correlation between LTC4S -444 A>C polymorphism and susceptibility to asthma: A meta-analysis and trial sequential analysis.

Background: This study aims to uncover the potential correlation between LTC4S -444 A>C polymorphism and susceptibility to asthma. Methods: Literatures reporting the correlation between LTC4S -444 A>C polymorphism and susceptibility to asthma published before 1st June, 2019 were searched in PubMed, Embase, Cochrane, Wanfang and CNKI. Eligible literatures were enrolled and their data were extracted. OR and its 95% CI were calculated for assessing the correlation between LTC4S -444 A>C polymorphism and susceptibility to asthma. The included data were weighted by an inverse variance and then analyzed by a fixed or random effects model. Heterogeneity test and sensitivity analysis were performed on the enrolled reports. STATA12.1 and TSA (trial sequential analysis) were utilized for analyses.

Identification of a novel Scn3b mutation in a Chinese Brugada syndrome pedigree: implications for Nav1.5 electrophysiological properties and intracellular distribution of Nav1.5 and Navß3.

Background: The Scn3b gene encodes for Navß3, a pivotal regulatory subunit of the fast sodium channel in cardiomyocytes. However, its mutation status in the Chinese population suffering from Brugada Syndrome (BrS) has not been characterized, and the contributory pathophysiological mechanisms to disease pathology remain undefined. Methods and Results: A Scn3b (c.260C>T, p.P87l) mutation was identified in a patient with BrS of Chinese descent. Functional analyses demonstrated that sodium channel activation for the wild type, mutant samples, and co-expression of both commenced at -55 mv and peaked at -25 mv. The mutant group exhibited a notable reduction, approximately 60%, in peak sodium channel activation current (INa) at -25 mv. The parameters for half-maximal activation voltages (V1/2) and slope factors (k) showed no significant differences when comparing wild type, mutant, and combined expression groups (P = 0.98 and P = 0.65, respectively). Additionally, no significant disparities were evident in terms of the steady-state sodium channel inactivation parameters V1/2 and k (with P-values of 0.85 and 0.25, respectively), nor were there significant differences in the activation time constant τ (P = 0.59) and late sodium current density (P = 0.23) across the wild-type, mutant, and co-expressed groups. Confocal imaging and Western blot analysis demonstrated decreased plasma membrane localization of SCN3B and SCN5A in the P87l group. Computational simulations of cardiac action potentials suggested that SCN3B P87l can alter the morphology of the action potentials within the endocardium and epicardium while reducing the peak of depolarization. Conclusions: The pathogenic impact of the Scn3b P87l mutation predominantly originates from a reduction in peak INa activation current coupled with decreased cell surface expression of Nav1.5 and Navß3. These alterations may influence cardiac action potential configurations and contribute to the risk of ventricular arrhythmias in individuals with BrS.

S-locus F-Box Protein as Pollen S determinant Targets Non-self S-RNase underlying Self-Incompatibility in Citrus.

Self-incompatibility (SI) is a crucial mechanism that prevents self-fertilization and inbreeding in flowering plants. Citrus exhibits SI regulated by a polymorphic S-locus containing an S-RNase gene and multiple S-locus F-box (SLF) genes. It has been documented that S-RNase functions as the pistil S determinant, but there is no direct evidence that the SLFs closely linked with S-RNase function as pollen S determinants in Citrus. This study assembled the genomes of two pummelo (Citrus grandis) plants and obtained three novel complete and well-annotated S-haplotypes and isolated 36 SLF or SLF-like alleles on the S-loci. Phylogenetic analysis of 138 SLFs revealed that the SLFs were classified into 12 types, including six types with divergent or missing alleles. Furthermore, transformation experiments verified that the conserved S6-SLF7a protein can lead the transition of SI to self-compatibility (SC) by recognizing non-self S8-RNase in 'Mini-Citrus' plants (S7S8 and S8S29, Fortunella hindsii), a model plant for citrus gene function studies. In vitro assays demonstrated interactions between SLFs of different S haplotypes and the Skp1-Cullin1-F-box subunit CgSSK1 protein. This study provides direct evidence that SLF controls the pollen function in Citrus, demonstrating its role in the 'non-self-recognition' SI system.

AMPK/MTOR/TP53 Signaling Pathway Regulation by Calcitonin Gene-Related Peptide Reduces Oxygen-Induced Lung Damage in Neonatal Rats through Autophagy Promotion.

Our previous studies indicated that calcitonin gene-related peptide (CGRP) alleviates hyperoxia-induced lung injury and suggested the possible involvement of autophagy in this process. Herein, we aimed to further explore the potential involvement of tumor protein p53 (TP53) and autophagy in the mode of action of CGRP against hyperoxia-induced lung injury in vitro and in vivo. The study conducted tests on type II alveolar epithelial cells (AECII) and rats that were subjected to hyperoxia treatment or combined treatment of hyperoxia with CGRP, CGRP inhibitor, rapamycin (an autophagy agonist), 3-methyladenine (3-MA, an autophagy inhibitor), TP53 silencing/inhibitor (pifithrin-α), or expression vector/activator (PRIMA-1 (2,2-bis(hydroxymethyl)-3-quinuclidinone)) and their corresponding controls. We found that oxidative stress, apoptosis, and autophagy were all increased by hyperoxia treatment in vitro. However, treating AECII cells with CGRP reversed hyperoxia-induced oxidative stress and apoptosis but further promoted autophagy. In addition, the combined treatment with rapamycin or TP53 silencing with CGRP promoted the effect of CGRP, while contrary results were obtained with combined therapy with 3-MA or TP53 overexpression. In vivo, the number of hyperoxia-induced autophagosomes was promoted in the lung tissue of neonatal rats. Furthermore, hyperoxia increased the expression levels of AMP-activated protein kinase (AMPK) alpha 1 (also known as protein kinase AMP-activated catalytic subunit alpha 1 (PRKAA1)) but inhibited TP53 and mechanistic target of rapamycin (MTOR); these expression trends were regulated by CGRP treatment. In conclusion, we showed that CGRP can attenuate hyperoxia-induced lung injury in neonatal rats by enhancing autophagy and regulating the TP53/AMPK/MTOR crosstalk axis.

Nebulized platelet-derived extracellular vesicles attenuate chronic cigarette smoke-induced murine emphysema.

Chronic obstructive pulmonary disease (COPD) is a prevalent lung disease usually resulting from cigarette smoking (CS). Cigarette smoking induces oxidative stress, which causes inflammation and alveolar epithelial cell apoptosis and represents a compelling therapeutic target for COPD. Purified human platelet-derived exosome product (PEP) is endowed with antioxidant enzymes and immunomodulatory molecules that mediate tissue repair. In this study, a murine model of CS-induced emphysema was used to determine whether nebulized PEP can influence the development of CS-induced emphysema through the mitigation of oxidative stress and inflammation in the lung. Nebulization of PEP effectively delivered the PEP vesicles into the alveolar region, with evidence of their uptake by type I and type II alveolar epithelial cells and macrophages. Lung function testing and morphometric assessment showed a significant attenuation of CS-induced emphysema in mice treated with nebulized PEP thrice weekly for 4 weeks. Whole lung immuno-oncology RNA sequencing analysis revealed that PEP suppressed several CS-induced cell injuries and inflammatory pathways. Validation of inflammatory cytokines and apoptotic protein expression on the lung tissue revealed that mice treated with PEP had significantly lower levels of S100A8/A9 expressing macrophages, higher levels of CD4+/FOXP3+ Treg cells, and reduced NF-κB activation, inflammatory cytokine production, and apoptotic proteins expression. Further validation using in vitro cell culture showed that pretreatment of alveolar epithelial cells with PEP significantly attenuated CS extract-induced apoptotic cell death. These data show that nebulization of exosomes like PEP can effectively deliver exosome cargo into the lung, mitigate CS-induced emphysema in mice, and suppress oxidative lung injury, inflammation, and apoptotic alveolar epithelial cell death.