Trained immunity of alveolar macrophages enhances injury resolution via KLF4-MERTK-mediated efferocytosis.

Recent studies suggest that training of innate immune cells such as tissue-resident macrophages by repeated noxious stimuli can heighten host defense responses. However, it remains unclear whether trained immunity of tissue-resident macrophages also enhances injury resolution to counterbalance the heightened inflammatory responses. Here, we studied lung-resident alveolar macrophages (AMs) prechallenged with either the bacterial endotoxin or with Pseudomonas aeruginosa and observed that these trained AMs showed greater resilience to pathogen-induced cell death. Transcriptomic analysis and functional assays showed greater capacity of trained AMs for efferocytosis of cellular debris and injury resolution. Single-cell high-dimensional mass cytometry analysis and lineage tracing demonstrated that training induces an expansion of a MERTKhiMarcohiCD163+F4/80low lung-resident AM subset with a proresolving phenotype. Reprogrammed AMs upregulated expression of the efferocytosis receptor MERTK mediated by the transcription factor KLF4. Adoptive transfer of these trained AMs restricted inflammatory lung injury in recipient mice exposed to lethal P. aeruginosa. Thus, our study has identified a subset of tissue-resident trained macrophages that prevent hyperinflammation and restore tissue homeostasis following repeated pathogen challenges.

Ginsenoside Rg1 alleviates sleep deprivation-induced learning and memory impairment by inhibiting excessive neuronal apoptosis in zebrafish.

Sleep deprivation impairs learning and memory. The neuroprotective function of ginsenoside Rg1 (Rg1) has been reported. This study aimed to investigate the alleviative effect and underlying mechanism of action of Rg1 on learning and memory deficits induced by sleep deprivation. Using 72 h of LED light to establish sleep deprivation model and treatment with Rg1-L (0.5 mg/ml), Rg1-H (1 mg/ml), and melatonin (positive control, 0.25 mg/ml), we investigated the behavioral performance of sleep deprivation zebrafish through 24 h autonomous movement tracking, a novel tank diving test, and a T-maze test. Brain injuries and ultrastructural changes were observed, brain water content was measured, and apoptotic events were analyzed using terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining. The oxidation-associated biomarkers superoxide dismutase, catalase, and glutathione peroxidase activity and lipid peroxidation product malondialdehyde content were detected. Real-time PCR and western blotting were performed to detect the levels of apoptotic molecules (Bax, caspase-3, and Bcl-2). Rg1-treatment was observed to improve the behavioral performance of sleep-deprivation fish, alleviate brain impairment, and increase oxidative stress-related enzyme activity. Rg1 can effectively exhibit neuroprotective functions and improve learning and memory impairments caused by sleep deprivation, which could be mediated by the Bcl-2/Bax/caspase-3 apoptotic signaling pathway (see Supplementary Video Abstract, Supplemental digital content, http://links.lww.com/WNR/A702 which demonstrates our research objectives, introduction overview of Rg1, and main direction of future research).

Ketone Body Rescued Seizure Behavior of LRP1 Deficiency in Drosophila by Modulating Glutamate Transport.

LRP1, the low-density lipoprotein receptor 1, would be a novel candidate gene of epilepsy according to our bioinformatic results and the animal study. In this study, we explored the role of LRP1 in epilepsy and whether beta-hydroxybutyrate, the principal ketone body of the ketogenic diet, can treat epilepsy caused by LRP1 deficiency in drosophila. UAS/GAL4 system was used to establish different genotype models. Flies were given standard, high-sucrose, and ketone body food randomly. The bang-sensitive test was performed on flies and seizure-like behavior was assessed. In morphologic experiments, we found that LRP1 deficiency caused partial loss of the ellipsoidal body and partial destruction of the fan-shaped body. Whole-body and glia LRP1 defect flies had a higher seizure rate compared to the control group. Ketone body decreased the seizure rate in behavior test in all LRP1 defect flies, compared to standard and high sucrose diet. Overexpression of glutamate transporter gene Eaat1 could mimic the ketone body effect on LRP1 deficiency flies. This study demonstrated that LRP1 defect globally or in glial cells or neurons could induce epilepsy in drosophila. The ketone body efficaciously rescued epilepsy caused by LRP1 knockdown. The results support screening for LRP1 mutations as discriminating conduct for individuals who require clinical attention and further clarify the mechanism of the ketogenic diet in epilepsy, which could help epilepsy patients make a precise treatment case by case.

Dynamic Demand Evaluation of COVID-19 Medical Facilities in Wuhan Based on Public Sentiment.

Medical facilities are an important part of urban public facilities and a vital pillar for the survival of citizens at critical times. During the rapid spread of coronavirus disease (COVID-19), Wuhan was forced into lockdown with a severe shortage of medical resources and high public tension. Adequate allocation of medical facilities is significant to stabilize citizens' emotions and ensure their living standards. This paper combines text sentiment analysis techniques with geographic information system (GIS) technology and uses a coordination degree model to evaluate the dynamic demand for medical facilities in Wuhan based on social media data and medical facility data. This study divided the epidemic into three phases: latent, outbreak and stable, from which the following findings arise: Public sentiment changed from negative to positive. Over half of the subdistricts in three phases were in a dysfunctional state, with a circular distribution of coordination levels decreasing from the city center to the outer. Thus, when facing major public health emergencies, Wuhan revealed problems of uneven distribution of medical facilities and unreasonable distribution of grades. This study aims to provide a basis and suggestions for the city to respond to major public health emergencies and optimize the allocation of urban medical facilities.

Ubl4A is critical for mitochondrial fusion process under nutrient deprivation stress.

Mitochondrial fusion and fission are dynamic processes regulated by the cellular microenvironment. Under nutrient starvation conditions, mitochondrial fusion is strengthened for energy conservation. We have previously shown that newborns of Ubl4A-deficient mice were more sensitive to starvation stress with a higher rate of mortality than their wild-type littermates. Ubl4A binds with the actin-related protein Arp2/3 complex to synergize the actin branching process. Here, we showed that deficiency in Ubl4A resulted in mitochondrial fragmentation and apoptosis. A defect in the fusion process was the main cause of the mitochondrial fragmentation and resulted from a shortage of primed Arp2/3 complex pool around the mitochondria in the Ubl4A-deficient cells compared to the wild-type cells. As a result, the mitochondrial fusion process was not undertaken quickly enough to sustain starvation stress-induced cell death. Consequently, fragmented mitochondria lost their membrane integrity and ROS was accumulated to trigger caspase 9-dependent apoptosis before autophagic rescue. Furthermore, the wild-type Ubl4A, but not the Arp2/3-binding deficient mutant, could rescue the starvation-induced mitochondrial fragmentation phenotype. These results suggest that Ubl4A promotes the mitochondrial fusion process via Arp2/3 complex during the initial response to nutrient deprivation for cell survival.

The C-terminus of Ubl4A is critical for pro-death activity and association with the Arp2/3 complex.

Ubl4A is a small ubiquitin-like protein involved in diverse cellular functions. We have shown that Ubl4A is critical for survival of the starvation-mediated cell death in vivo. The underlying mechanism for this is through interaction with the actin-related protein Arp2/3 complex and promotion of actin branching. Interestingly, "put-back" of Ubl4A to Ubl4A-deficient cells also results in cell death. Removal of the Ubl4A N-terminus significantly enhances its cytotoxicity, indicating that the pro-death activity of Ubl4A is mainly from its C-terminal region. In vitro protein pull-down assays show that the C-terminal region of Ubl4A can directly interact with the Arp2/3 complex. The single point mutation of an aspartic acid to alanine (D122A) in the Ubl4A C-terminus abolishes its ability to bind the Arp2/3 complex. This mutation also destabilizes Ubl4A proteins susceptible to protease degradation. Importantly, ectopic expression of wild-type Ubl4A can induce cell death in colon cancer cells, but such pro-death activity is diminished in the D122A mutant. These data suggest that Ubl4A C-terminus, especially D122, is critical for Ubl4A-Arp2/3 interaction and its pro-death function.

Label-Free Detection of DNA Mutations by Nanopore Analysis.

Cancers are caused by mutations to genes that regulate cell normal functions. The capability to rapid and reliable detection of specific target gene variations can facilitate early disease detection and diagnosis and also enables personalized treatment of cancer. Most of the currently available methods for DNA mutation detection are time-consuming and/or require the use of labels or sophisticated instruments. In this work, we reported a label-free enzymatic reaction-based nanopore sensing strategy to detect DNA mutations, including base substitution, deletion, and insertion. The method was rapid and highly sensitive with a detection limit of 4.8 nM in a 10 min electrical recording. Furthermore, the nanopore assay could differentiate among perfect match, one mismatch, and two mismatches. In addition, simulated serum samples were successfully analyzed. Our developed nanopore-based DNA mutation detection strategy should find useful application in genetic diagnosis.