LYSMD proteins promote activation of Rab32-family GTPases for lysosome-related organelle biogenesis.

Lysosome-related organelles (LROs) are specialized lysosomes with cell type-specific roles in organismal homeostasis. Dysregulation of LROs leads to many human disorders, but the mechanisms underlying their biogenesis are not fully understood. Here, we identify a group of LYSMD proteins as evolutionarily conserved regulators of LROs. In Caenorhabditis elegans, mutations of LMD-2, a LysM domain-containing protein, reduce the levels of the Rab32 GTPase ortholog GLO-1 on intestine-specific LROs, the gut granules, leading to their abnormal enlargement and defective biogenesis. LMD-2 interacts with GLO-3, a subunit of GLO-1 guanine nucleotide exchange factor (GEF), thereby promoting GLO-1 activation. Mammalian homologs of LMD-2, LYSMD1, and LYSMD2 can functionally replace LMD-2 in C. elegans. In mammals, LYSMD1/2 physically interact with the HPS1 subunit of BLOC-3, the GEF of Rab32/38, thus promoting Rab32 activation. Inactivation of both LYSMD1 and LYSMD2 reduces Rab32 activation, causing melanosome enlargement and decreased melanin production in mouse melanoma cells. These findings provide important mechanistic insights into LRO biogenesis and functions.

Heterogeneity of immune cells and their communications unveiled by transcriptome profiling in acute inflammatory lung injury.

Background: Acute Respiratory Distress Syndrome (ARDS) or its earlier stage Acute lung injury (ALI), is a worldwide health concern that jeopardizes human well-being. Currently, the treatment strategies to mitigate the incidence and mortality of ARDS are severely restricted. This limitation can be attributed, at least in part, to the substantial variations in immunity observed in individuals with this syndrome. Methods: Bulk and single cell RNA sequencing from ALI mice and single cell RNA sequencing from ARDS patients were analyzed. We utilized the Seurat program package in R and cellmarker 2.0 to cluster and annotate the data. The differential, enrichment, protein interaction, and cell-cell communication analysis were conducted. Results: The mice with ALI caused by pulmonary and extrapulmonary factors demonstrated differential expression including Clec4e, Retnlg, S100a9, Coro1a, and Lars2. We have determined that inflammatory factors have a greater significance in extrapulmonary ALI, while multiple pathways collaborate in the development of pulmonary ALI. Clustering analysis revealed significant heterogeneity in the relative abundance of immune cells in different ALI models. The autocrine action of neutrophils plays a crucial role in pulmonary ALI. Additionally, there was a significant increase in signaling intensity between B cells and M1 macrophages, NKT cells and M1 macrophages in extrapulmonary ALI. The CXCL, CSF3 and MIF, TGFß signaling pathways play a vital role in pulmonary and extrapulmonary ALI, respectively. Moreover, the analysis of human single-cell revealed DCs signaling to monocytes and neutrophils in COVID-19-associated ARDS is stronger compared to sepsis-related ARDS. In sepsis-related ARDS, CD8+ T and Th cells exhibit more prominent signaling to B-cell nucleated DCs. Meanwhile, both MIF and CXCL signaling pathways are specific to sepsis-related ARDS. Conclusion: This study has identified specific gene signatures and signaling pathways in animal models and human samples that facilitate the interaction between immune cells, which could be targeted therapeutically in ARDS patients of various etiologies.

The impact of delayed tracheostomy on critically ill patients receiving mechanical ventilation: a retrospective cohort study in a chinese tertiary hospital.

OBJECTIVES: The timing of tracheostomy for critically ill patients on mechanical ventilation (MV) is a topic of controversy. Our objective was to determine the most suitable timing for tracheostomy in patients undergoing MV. DESIGN: Retrospective cohort study. SETTING AND PARTICIPANTS: One thousand eight hundred eighty-four hospitalisations received tracheostomy from January 2011 to December 2020 in a Chinese tertiary hospital. METHODS: Tracheostomy timing was divided into three groups: early tracheostomy (ET), intermediate tracheostomy (IMT), and late tracheostomy (LT), based on the duration from tracheal intubation to tracheostomy. We established two criteria to classify the timing of tracheostomy for data analysis: Criteria I (ET ≤ 5 days, 5 days < IMT ≤ 10 days, LT > 10 days) and Criteria II (ET ≤ 7 days, 7 days < IMT ≤ 14 days, LT > 14 days). Parameters such as length of ICU stay, length of hospital stay, and duration of MV were used to evaluate outcomes. Additionally, the outcomes were categorized as good prognosis, poor prognosis, and death based on the manner of hospital discharge. Student's t-test, analysis of variance (ANOVA), Mann-Whitney U test, Kruskal-Wallis test, Chi-square test, and Fisher's exact test were employed as appropriate to assess differences in demographic data and individual characteristics among the ET, IMT, and LT groups. Univariate Cox regression model and multivariable Cox proportional hazards regression model were utilized to determine whether delaying tracheostomy would increase the risk of death. RESULTS: In both of two criterion, patients with delayed tracheostomies had longer hospital stays (p < 0.001), ICU stays (p < 0.001), total time receiving MV (p < 0.001), time receiving MV before tracheostomy (p < 0.001), time receiving MV after tracheostomy (p < 0.001), and sedation durations. Similar results were also found in sub-population diagnosed as trauma, neurogenic or digestive disorders. Multinomial Logistic regression identified LT was independently associated with poor prognosis, whereas ET conferred no clinical benefits compared with IMT. CONCLUSIONS: In a mixed ICU population, delayed tracheostomy prolonged ICU and hospital stays, sedation durations, and time receiving MV. Multinomial logistic regression analysis identified delayed tracheostomies as independently correlated with worse outcomes. TRIAL REGISTRATION: ChiCTR2100043905. Registered 05 March 2021. http://www.chictr.org.cn/listbycreater.aspx.

Effects of light-felling intensity on hydrological effects of litter in Korean pine forests by 'planting conifer and preserving broadleaved tree' in Xiaoxing'an Mountains of China.

To understand the effects of 'planting conifer and preserving broadleaved tree' and light-felling on the hydrological effects of litter layer during the restoration of the climax vegetation broad-leaved Korean pine forest in temperate zone of Northeast China, we measured litter accumulation, water holding process of litter, and maximum holding water, maximum blocking and effective blocking amount of litter layers using sample survey method and indoor immersion method in three forests (aspen-Korean pine forests, white birch-Korean pine forest, and Mongolian oak-Korean pine forest) under different light-felling intensity (control, C; low light-felling, L; moderate light-felling, M; heavy light-felling, H) in Xiaoxing'an Mountains. The results showed that the intensity of light-felling had different effects on litter accumulation (7.32 to 15.58 t·hm-2) in three forest types. L, M and H significantly enhanced litter accumulation by 24.3%-34.6% in the Mongolian oak-Korean pine forest, L and M enhance it by 15.3%-19.3% in aspen-Korean pine forest, and H enhance it by 27.1% in white birch-Korean pine forest. Water holding capacity (W) and water absorption rate (V) of the undecomposed layer and the semi-decomposed layer of the litter were in accordance with the relationship between the soaking time (t): W=alnt+b (R2>0.908), V=ktn (R2≥0.999). The intensity of light-felling (except H in aspen-Korean pine forests) increased the maximum water holding capacity (17.86-45.12 t·hm-2), maximum interception capacity (16.10-34.19 t·hm-2) and effective interception capacity (13.42-27.42 t·hm-2) of litter by 30.1%-74.8%, 27.4%-83.6% and 26.7%-86.0%, respectively, while changed the differences of effective blocking amount of litters among forest types. Therefore, light-felling significantly enhanced the hydro-ecological function of litter layers in the medium-term broad-leaved Korean pine forests by 'planting conifer and preserving broadleaved tree'. The low, moderate, and heavy light-felling was best one for the Mongolian oak-Korean pine forest, the aspen-Korean pine forest, and the white birch-Korean pine forest, respectively.

Neurogenic pulmonary edema following acute stroke: The progress and perspective.

Neurogenic pulmonary edema (NPE) following acute stroke is an acute respiratory distress syndrome (ARDS) with clinical characteristics that include acute onset, apparent pulmonary interstitial fluid infiltration and rapid resolution. The pathological process of NPE centers on sympathetic stimulation and fulminant release of catecholamines, which cause contraction of resistance vessels. Elevated systemic resistance forces fluid into pulmonary circulation, while pulmonary circulation overload induces pulmonary capillary pressure that elevates, and in turn damages the alveolar capillary barrier. Damage to the alveolar capillary barrier leads to pulmonary ventilation disorder, blood perfusion disorder and oxygenation disorder. Eventually, NPE will cause post-stroke patients' prognosis to further deteriorate. At present, we lack specific biological diagnostic indicators and a meticulously unified diagnostic criterion, and this results in a situation in which many patients are not recognized quickly and/or diagnosed accurately. There are no drugs that are effective against NPE. Therefore, understanding how to diagnose NPE early by identifying the risk factors and how to apply appropriate treatment to avoid a deteriorating prognosis are important scientific goals. We will elaborate the progress of NPE after acute stroke in terms of its pathophysiological mechanisms, etiology, epidemiology, clinical diagnosis and early prediction, comprehensive treatment strategies, and novel drug development. We also propose our own thinking and prospects regarding NPE.

Cigarette smoke-initiated autoimmunity facilitates sensitisation to elastin-induced COPD-like pathologies in mice.

It is currently not understood whether cigarette smoke exposure facilitates sensitisation to self-antigens and whether ensuing auto-reactive T cells drive chronic obstructive pulmonary disease (COPD)-associated pathologies.To address this question, mice were exposed to cigarette smoke for 2 weeks. Following a 2-week period of rest, mice were challenged intratracheally with elastin for 3 days or 1 month. Rag1-/- , Mmp12-/- , and Il17a-/- mice and neutralising antibodies against active elastin fragments were used for mechanistic investigations. Human GVAPGVGVAPGV/HLA-A*02:01 tetramer was synthesised to assess the presence of elastin-specific T cells in patients with COPD.We observed that 2 weeks of cigarette smoke exposure induced an elastin-specific T cell response that led to neutrophilic airway inflammation and mucus hyperproduction following elastin recall challenge. Repeated elastin challenge for 1 month resulted in airway remodelling, lung function decline and airspace enlargement. Elastin-specific T cell recall responses were dose dependent and memory lasted for over 6 months. Adoptive T cell transfer and studies in T cells deficient Rag1-/- mice conclusively implicated T cells in these processes. Mechanistically, cigarette smoke exposure-induced elastin-specific T cell responses were matrix metalloproteinase (MMP)12-dependent, while the ensuing immune inflammatory processes were interleukin 17A-driven. Anti-elastin antibodies and T cells specific for elastin peptides were increased in patients with COPD.These data demonstrate that MMP12-generated elastin fragments serve as a self-antigen and drive the cigarette smoke-induced autoimmune processes in mice that result in a bronchitis-like phenotype and airspace enlargement. The study provides proof of concept of cigarette smoke-induced autoimmune processes and may serve as a novel mouse model of COPD.

The amino acid transporter SLC-36.1 cooperates with PtdIns3P 5-kinase to control phagocytic lysosome reformation.

Phagocytic removal of apoptotic cells involves formation, maturation, and digestion of cell corpse-containing phagosomes. The retrieval of lysosomal components following phagolysosomal digestion of cell corpses remains poorly understood. Here we reveal that the amino acid transporter SLC-36.1 is essential for lysosome reformation during cell corpse clearance in Caenorhabditis elegans embryos. Loss of slc-36.1 leads to formation of phagolysosomal vacuoles arising from cell corpse-containing phagosomes. In the absence of slc-36.1, phagosome maturation is not affected, but the retrieval of lysosomal components is inhibited. Moreover, loss of PPK-3, the C. elegans homologue of the PtdIns3P 5-kinase PIKfyve, similarly causes accumulation of phagolysosomal vacuoles that are defective in phagocytic lysosome reformation. SLC-36.1 and PPK-3 function in the same genetic pathway, and they directly interact with one another. In addition, loss of slc-36.1 and ppk-3 causes strong defects in autophagic lysosome reformation in adult animals. Our findings thus suggest that the PPK-3-SLC-36.1 axis plays a central role in both phagocytic and autophagic lysosome formation.

GOP-1 promotes apoptotic cell degradation by activating the small GTPase Rab2 in C. elegans.

Apoptotic cells generated by programmed cell death are engulfed by phagocytes and enclosed within plasma membrane-derived phagosomes. Maturation of phagosomes involves a series of membrane-remodeling events that are governed by the sequential actions of Rab GTPases and lead to formation of phagolysosomes, where cell corpses are degraded. Here we identified gop-1 as a novel regulator of apoptotic cell clearance in Caenorhabditis elegans Loss of gop-1 affects phagosome maturation through the RAB-5-positive stage, causing defects in phagosome acidification and phagolysosome formation, phenotypes identical to and unaffected by loss of unc-108, the C. elegans Rab2 GOP-1 transiently associates with cell corpse-containing phagosomes, and loss of its function abrogates phagosomal association of UNC-108. GOP-1 interacts with GDP-bound and nucleotide-free UNC-108/Rab2, disrupts GDI-UNC-108 complexes, and promotes activation and membrane recruitment of UNC-108/Rab2 in vitro. Loss of gop-1 also abolishes association of UNC-108 with endosomes, causing defects in endosome and dense core vesicle maturation. Thus, GOP-1 is an activator of UNC-108/Rab2 in multiple processes.

Herbal Medicines for Asthmatic Inflammation: From Basic Researches to Clinical Applications.

Asthma is one of the most common chronic inflammatory disorders, associated with reversible airflow obstruction, airway hyperresponsiveness, and airway remodeling. This disease has a significant impact on individuals, their families, and society. Standardized therapeutics such as inhaled corticosteroid in combination with long acting ß2 agonist have been applied for asthma control; however, complementary and alternative medicines, especially herbal medicines, are still widely used all over the world. A growing body of literature suggests that various herbals or related products might be effective in inhibiting asthmatic inflammation. In this review, we summarize recent advances about the mechanistic studies of herbal medicines on allergic airway inflammation in animal models and their potential application into clinic for asthma control.

Autophagy plays an essential role in cigarette smoke-induced expression of MUC5AC in airway epithelium.

Mucus hypersecretion is a common pathological feature of chronic airway inflammatory diseases including chronic obstructive pulmonary disease (COPD). However, the molecular basis for this condition remains incompletely understood. We have previously demonstrated a critical role of autophagy in COPD pathogenesis through mediating apoptosis of lung epithelial cells. In this study, we aimed to investigate the function of autophagy as well as its upstream and downstream signals in cigarette smoke-induced mucus production in human bronchial epithelial (HBE) cells and in mouse airways. Cigarette smoke extract (CSE), as well as the classical autophagy inducers starvation or Torin-1, significantly triggered MUC5AC expression, and inhibition of autophagy markedly attenuated CSE-induced mucus production. The CSE-induced autophagy was mediated by mitochondrial reactive oxygen species (mitoROS), which regulated mucin expression through the JNK and activator protein-1 pathway. Epidermal growth factor receptor (EGFR) was also required for CSE-induced MUC5AC in HBE cells, but it exerted inconsiderable effects on the autophagy-JNK signaling cascade. Airways of mice with dysfunctional autophagy-related genes displayed a markedly reduced number of goblet cells and attenuated levels of Muc5ac in response to cigarette smoke exposure. These results altogether suggest that mitoROS-dependent autophagy is essential for cigarette smoke-induced mucus hyperproduction in airway epithelial cells, and reemphasize autophagy inhibition as a novel therapeutic strategy for chronic airway diseases.

Molecular dynamics simulation of the interactions between EHD1 EH domain and multiple peptides.

OBJECTIVE: To provide essential information for peptide inhibitor design, the interactions of Eps15 homology domain of Eps15 homology domain-containing protein 1 (EHD1 EH domain) with three peptides containing NPF (asparagine-proline-phenylalanine), DPF (aspartic acid-proline-phenylalanine), and GPF (glycine-proline-phenylalanine) motifs were deciphered at the atomic level. The binding affinities and the underlying structure basis were investigated. METHODS: Molecular dynamics (MD) simulations were performed on EHD1 EH domain/peptide complexes for 60 ns using the GROMACS package. The binding free energies were calculated and decomposed by molecular mechanics/generalized Born surface area (MM/GBSA) method using the AMBER package. The alanine scanning was performed to evaluate the binding hot spot residues using FoldX software. RESULTS: The different binding affinities for the three peptides were affected dominantly by van der Waals interactions. Intermolecular hydrogen bonds provide the structural basis of contributions of van der Waals interactions of the flanking residues to the binding. CONCLUSIONS: van der Waals interactions should be the main consideration when we design peptide inhibitors of EHD1 EH domain with high affinities. The ability to form intermolecular hydrogen bonds with protein residues can be used as the factor for choosing the flanking residues.

[Mapping of the lethal genes in the sex-linkaged balanced lethal silkworm Bombyx mori using SSR markers].

The males of sex-linkaged balanced lethal silkworm strain (S-14) has two non-allelic recessive genes (lethal gene 1, l1 and lethal gene 2, l2). The two genes are located on two different Z chromosomes and cause death of embryos at body pigmentation stage and end reversal embryo stage, respectively. We firstly hybridized the males of S-14 strain with the females having wild-type genes of P50 strain and then backcrossed the males of F1 with females of P50 strain. A total of 1660 female moths of BC1 generation were divided into two groups, 1100 in BC1-l1 and 560 in BC1-l2 according to the lethal gene carried by these female moths' fathers-fame moths of F1, respectively. Based on the nucleotide sequence information from the published physical map of Bombyx mori, we developed 16 polymorphic SSR markers in l1 gene region and 18 polymorphic SSR makers in l2 gene region compared to the allelic region of P50 strain and used these SSR markers and groups of BC1-l1 and BC1-12 to map the two lethal genes, respectively. Gene l1 was mapped on the region of Z chromosome, covering a physical distance of 2.60 Mb. Gene l2 was fine mapped on the region of Z chromosome, covering a physical distance of 0.69 Mb.