Rapamycin Exacerbates Staphylococcus aureus Pneumonia by Inhibiting mTOR-RPS6 in Macrophages.

Purpose: This study aimed to explore the effect of Rapamycin (Rapa) in Staphylococcus aureus (S. aureus) pneumonia and clarify its possible mechanism. Methods: We investigated the effects of Rapa on S. aureus pneumonia in mouse models and in macrophages cultured in vitro. Two possible mechanisms were investigated: the mTOR-RPS6 pathway phosphorylation and phagocytosis. Furthermore, for the mechanism verification in vivo, mice with specific Mtor knockout in myeloid cells were constructed for pneumonia models. Results: Rapa exacerbated S. aureus pneumonia in mouse models, promoting chemokines secretion and inflammatory cells infiltration in lung. In vitro, Rapa upregulated the secretion of chemokines and cytokines in macrophages induced by S. aureus. Mechanistically, the mTOR-ribosomal protein S6 (RPS6) pathway in macrophages was phosphorylated in response to S. aureus infection, and the inhibition of RPS6 phosphorylation upregulated the inflammation level. However, Rapa did not increase the phagocytic activity. Accordingly, mice with specific Mtor knockout in myeloid cells experienced more severe S. aureus pneumonia. Conclusion: Rapa exacerbates S. aureus pneumonia by increasing the inflammatory levels of macrophages. Inhibition of mTOR-RPS6 pathway upregulates the expression of cytokines and chemokines in macrophages, thus increases inflammatory cells infiltration and exacerbates tissue damage.

Airway epithelial cGAS inhibits LPS-induced acute lung injury through CREB signaling.

Increased levels of cytosolic DNA in lung tissues play an important role in acute lung injury. However, the detailed mechanisms involved remain elusive. Here, we found that cyclic GMP-AMP synthase (cGAS, a cytosolic DNA sensor) expression was increased in airway epithelium in response to increased cytosolic DNA. Conditional deletion of airway epithelial cGAS exacerbated acute lung injury in mice, cGAS knockdown augmented LPS-induced production of interleukin (IL)-6 and IL-8. Mechanically, deletion of cGAS augmented expression of phosphorylated CREB (cAMP response element-binding protein), and cGAS directly interacted with CREB via its C-terminal domain. Furthermore, CREB knockdown rescued the LPS-induced excessive inflammatory response caused by cGAS deletion. Our study demonstrates that airway epithelial cGAS plays a protective role in acute lung injury and confirms a non-canonical cGAS-CREB pathway that regulates the inflammatory responses in airway epithelium to mediate LPS-induced acute lung injury.

A general urban spreading pattern of COVID-19 and its underlying mechanism.

Currently, the global situation of COVID-19 is aggravating, pressingly calling for efficient control and prevention measures. Understanding the spreading pattern of COVID-19 has been widely recognized as a vital step for implementing non-pharmaceutical measures. Previous studies explained the differences in contagion rates due to the urban socio-political measures, while fine-grained geographic urban spreading pattern still remains an open issue. Here, we fill this gap by leveraging the trajectory data of 197,808 smartphone users (including 17,808 anonymous confirmed cases) in nine cities in China. We find a general spreading pattern in all cities: the spatial distribution of confirmed cases follows a power-law-like model and the spreading centroid human mobility is time-invariant. Moreover, we reveal that long average traveling distance results in a high growth rate of spreading radius and wide spatial diffusion of confirmed cases in the fine-grained geographic model. With such insight, we adopt the Kendall model to simulate the urban spreading of COVID-19 which can well fit the real spreading process. Our results unveil the underlying mechanism behind the spatial-temporal urban evolution of COVID-19, and can be used to evaluate the performance of mobility restriction policies implemented by many governments and to estimate the evolving spreading situation of COVID-19.

The Scap-SREBP1-S1P/S2P lipogenesis signal orchestrates the homeostasis and spatiotemporal activation of NF-κB.

The nuclear factor κB (NF-κB) pathway plays essential roles in innate and adaptive immunity, but little is known how NF-κB signaling is compartmentalized and spatiotemporally activated in the cytoplasm. Here, we show that the lipogenesis signal cascade Scap-SREBP1-S1P/S2P orchestrates the homeostasis and spatiotemporal activation of NF-κB. SREBP cleavage-activating protein (Scap) and sterol regulatory element-binding protein 1 (SREBP1) form a super complex with inhibitors of NF-κB α (IκBα) to associate NF-κB close to the endoplasmic reticulum (ER). Upon lipopolysaccharide (LPS) stimulation, Scap transports the complex to the Golgi apparatus, where SREBP1 is cleaved by site-1 protease (S1P)/S2P, liberating IκBα for IκB kinase (Ikk)-mediated phosphorylation and subsequent activation of NF-κB. Loss of Scap or inhibition of S1P or S2P diminishes, while SREBP1 deficiency augments, LPS-induced NF-κB activation and subsequent inflammatory responses. Our results reveal the Scap-SREBP1 complex as an additional cytoplasmic checkpoint for NF-κB homeostasis and unveil the Golgi apparatus as the optimal cellular platform for NF-κB activation, providing insights into the crosstalk between lipogenesis signaling and immunity.

Potent antitumor activity of ensartinib in MET exon 14 skipping-mutated non-small cell lung cancer.

Met proto-oncogene exon 14 skipping (METex14) mutations are targetable driver genes in approximately 3% of non-small-cell lung cancers (NSCLCs). Ensartinib, a type Ia MET inhibitor, is a multi-kinase inhibitor that has been approved for ALK-positive NSCLCs. Ensartinib was administered for compassionate use (cohort 1) and in a phase II clinical trial (cohort 2) to patients with METex14 mutant NSCLCs, with ORR as a primary endpoint. Molecular simulation was conducted to evaluate ensartinib c-MET interaction, and cell lines, patient-derived organoids (PDOs), and xenograft models were used to test the effectiveness of ensartinib. Among 29 evaluable patients, the ORR and DCR of ensartinib were 67% and 94% in cohort 1, and 73% and 91% in cohort 2. The median DoR was 6.8 months and median PFS was 6.1 months in the total population. Rash was the most common drug-related adverse event, and peripheral edema of any grade was reported in only 9% patients. Molecular simulations indicated favorable binding of ensartinib to c-MET. The kinase assay demonstrated an IC50 of 7.9 nM of ensartinib against METex14 protein. In vitro, Hs746T (METex14 mutation) and EBC-1 (MET amplification) cells were sensitive to ensartinib, with IC50 values of 31 and 44 nM, respectively. Ensartinib exhibited comparable inhibitory effects on cell migration as crizotinib and tepotinib in both cell types. In vivo, ensartinib suppressed the growth of Hs746T cells. Ensartinib also potently inhibited the viability of PDOs. Overall, Ensartinib exhibited substantial antitumor effects against METex14 mutant NSCLCs in preclinical and clinical trials, with relatively low peripheral edema rates.

Eosinophils: A Friend or Foe in Human Health and Diseases.

Background: Since their discovery, around 150 years, eosinophils research has been a field of changing perspective, and new directions are emerging since then. Summary: Initially, eosinophils were perceived as terminally differentiated cytotoxic effector cells. Clearly, eosinophils are capable of playing functions other than immune responses, which is not surprising given their intricate interactions with pathogens as well as other circulating leukocytes. Attempts to comprehend the eosinophil biology and functions have yielded remarkable insights into their roles in human health and sickness. The use of FDA-approved eosinophils-targeting biologics has provided exciting opportunities to directly explore the contributions of eosinophils in disease etiology in humans. Key Messages: In this review, we will focus on the eosinophils' lifecycle and discuss the current state of knowledge from mouse models and retrospective human studies demonstrating eosinophils' roles in the pathogenesis of human diseases such as asthma, cancer, and kidney disorders. Despite three recently approved anti-eosinophil agents, a number of key questions and challenges remain far from settled, thereby generating opportunity to further explore this enigmatic cell. A comprehensive understanding of eosinophils biology and function will surely aid in developing improved therapeutic strategies against eosinophils-associated disorders.

The clinical application value of compound Stachys sieboldii Miq granules to stable COPD patients.

BACKGROUND: The aim of this paper was to explore the application value of Stachys sieboldii Miq granules which is a kind of traditional Chinese medicine (TCM) in stable chronic obstructive pulmonary disease (COPD) patients. METHODS: Randomized double-blind method was used to select 160 patients with stable COPD. The patients were randomly divided into placebo group and Stachys sieboldii Miq group. Both groups underwent test items for 2 months, detected plasma cytokines, Saint George Respiratory Questionnaire (SGRQ) scores, pulmonary function, and the frequency of acute exacerbation (AE) at week 12. Follow-up was done every 12 weeks till 48 weeks to record the frequency of AE. RESULTS: A total of 120 patients with 60 in each group were included. At week 12, there were significant differences in the plasma concentrations of TH17, IL-17A, IFN-γ and IL-10 between the two groups (all P=0.000). The proinflammatory factors TH17 and IL-17A were significantly lower in control group, while the anti-inflammatory factors IFN-γ and IL-10 were higher in the control group. And the SGRQ Score of Stachys sieboldii Miq group was significantly lower. There was no significant difference in lung function (FEV1, FVC, and FEV1/FVC) between the two groups (P=0.510, 0.529, and 0.843). Within 48 weeks, the AE frequency and change with time showed significant differences between the two groups (P=0.029), and the incidence of AE was reduced by 47.9% in Stachys sieboldii Miq group. CONCLUSIONS: Stachys sieboldii Miq granules reduced proinflammatory factors and increased anti-inflammatory factors in stable COPD patients, reducing the probability of inducing AE treatment.

Treatment of allergic eosinophilic asthma through engineered IL-5-anchored chimeric antigen receptor T cells.

Severe eosinophilic asthma (SEA) is a therapy-resistant respiratory condition with poor clinical control. Treatment efficacy and patient compliance of current therapies remain unsatisfactory. Here, inspired by the remarkable success of chimeric antigen receptor-based cellular adoptive immunotherapies demonstrated for the treatment of a variety of malignant tumors, we engineered a cytokine-anchored chimeric antigen receptor T (CCAR-T) cell system using a chimeric IL-5-CD28-CD3ζ receptor to trigger T-cell-mediated killing of eosinophils that are elevated during severe asthma attacks. IL-5-anchored CCAR-T cells exhibited selective and effective killing capacity in vitro and restricted eosinophil differentiation with apparent protection against allergic airway inflammation in two mouse models of asthma. Notably, a single dose of IL-5-anchored CCAR-T cells resulted in persistent protection against asthma-related conditions over three months, significantly exceeding the typical therapeutic window of current mAb-based treatments in the clinics. This study presents a cell-based treatment strategy for SEA and could set the stage for a new era of precision therapies against a variety of intractable allergic diseases in the future.

New Era of Mapping and Understanding Common Fragile Sites: An Updated Review on Origin of Chromosome Fragility.

Common fragile sites (CFSs) are specific genomic loci prone to forming gaps or breakages upon replication perturbation, which correlate well with chromosomal rearrangement and copy number variation. CFSs have been actively studied due to their important pathophysiological relevance in different diseases such as cancer and neurological disorders. The genetic locations and sequences of CFSs are crucial to understanding the origin of such unstable sites, which require reliable mapping and characterizing approaches. In this review, we will inspect the evolving techniques for CFSs mapping, especially genome-wide mapping and sequencing of CFSs based on current knowledge of CFSs. We will also revisit the well-established hypotheses on the origin of CFSs fragility, incorporating novel findings from the comprehensive analysis of finely mapped CFSs regarding their locations, sequences, and replication/transcription, etc. This review will present the most up-to-date picture of CFSs and, potentially, a new framework for future research of CFSs.

Molecular insights into ligand recognition and activation of chemokine receptors CCR2 and CCR3.

Chemokine receptors are a family of G-protein-coupled receptors with key roles in leukocyte migration and inflammatory responses. Here, we present cryo-electron microscopy structures of two human CC chemokine receptor-G-protein complexes: CCR2 bound to its endogenous ligand CCL2, and CCR3 in the apo state. The structure of the CCL2-CCR2-G-protein complex reveals that CCL2 inserts deeply into the extracellular half of the transmembrane domain, and forms substantial interactions with the receptor through the most N-terminal glutamine. Extensive hydrophobic and polar interactions are present between both two chemokine receptors and the Gα-protein, contributing to the constitutive activity of these receptors. Notably, complemented with functional experiments, the interactions around intracellular loop 2 of the receptors are found to be conserved and play a more critical role in G-protein activation than those around intracellular loop 3. Together, our findings provide structural insights into chemokine recognition and receptor activation, shedding lights on drug design targeting chemokine receptors.

A Spontaneous H2-Aa Point Mutation Impairs MHC II Synthesis and CD4+ T-Cell Development in Mice.

Major histocompatibility complex class II (MHC II) is an essential immune regulatory molecule that plays an important role in antigen presentation and T-cell development. Abnormal MHC II expression can lead to immunodeficiency, clinically termed as type II bare lymphocyte syndrome (BLS), which usually results from mutations in the MHC II transactivator (CIITA) and other coactivators. Here, we present a new paradigm for MHC II deficiency in mice that involves a spontaneous point mutation on H2-Aa. A significantly reduced population of CD4+ T cells was observed in mice obtained from the long-term homozygous breeding of autophagy-related gene microtubule-associated protein 1 light chain 3 ß (Map1lc3b, Lc3b) knockout mice; this phenotype was not attributed to the original knocked-out gene. MHC II expression was generally reduced, together with a marked deficiency of H2-Aa in the immune cells of these mice. Using cDNA and DNA sequencing, a spontaneous H2-Aa point mutation that led to false pre-mRNA splicing, deletion of eight bases in the mRNA, and protein frameshift was identified in these mice. These findings led to the discovery of a new type of spontaneous MHC II deficiency and provided a new paradigm to explain type II BLS in mice.

PICH Supports Embryonic Hematopoiesis by Suppressing a cGAS-STING-Mediated Interferon Response.

The Plk1-interacting checkpoint helicase (PICH) protein localizes to ultrafine anaphase DNA bridges in mitosis along with a complex of DNA repair proteins. Previous studies show PICH deficiency-induced embryonic lethality in mice. However, the function of PICH that is required to suppress embryonic lethality in PICH-deficient mammals remains to be determined. Previous clinical studies suggest a link between PICH deficiency and the onset of acquired aplastic anemia. Here, using Pich knock-out (KO) mouse models, the authors provide evidence for a mechanistic link between PICH deficiency and defective hematopoiesis. Fetal livers from Pich-KO embryos exhibit a significantly elevated number of hematopoietic stem cells (HSCs); however, these HSCs display a higher level of apoptosis and a much-reduced ability to reconstitute a functional hematopoietic system when transplanted into lethally irradiated recipients. Moreover, these HSCs show an elevated cytoplasmic dsDNA expression and an activation of the cGAS-STING pathway, resulting in excessive production of type I interferons (IFN). Importantly, deletion of Ifnar1 or cGAS reverses the defective hematopoiesis. The authors conclude that loss of PICH results in defective hematopoiesis via cGAS-STING-mediated type I IFN production.

Identification and mechanism of G protein-biased ligands for chemokine receptor CCR1.

Biased signaling of G protein-coupled receptors describes an ability of different ligands that preferentially activate an alternative downstream signaling pathway. In this work, we identified and characterized different N-terminal truncations of endogenous chemokine CCL15 as balanced or biased agonists targeting CCR1, and presented three cryogenic-electron microscopy structures of the CCR1-Gi complex in the ligand-free form or bound to different CCL15 truncations with a resolution of 2.6-2.9 Å, illustrating the structural basis of natural biased signaling that initiates an inflammation response. Complemented with pharmacological and computational studies, these structures revealed it was the conformational change of Tyr291 (Y2917.43) in CCR1 that triggered its polar network rearrangement in the orthosteric binding pocket and allosterically regulated the activation of ß-arrestin signaling. Our structure of CCL15-bound CCR1 also exhibited a critical site for ligand binding distinct from many other chemokine-receptor complexes, providing new insights into the mode of chemokine recognition.

Perspectives and Management of Atypical Asthma in Chinese Specialists and Primary Care Practitioners-A Nationwide Questionnaire Survey.

Background and objective: To evaluate the awareness/knowledge and clinical practice for the treatment of atypical asthma among respiratory specialists and primary care practitioners (PCPs) in China. Methods: A total number of 1,997 physicians participated in the survey via WeChat. The questionnaire included six main items: physician demographic characteristics, awareness, diagnosis, medical prescription, assessment/education, and proposal. Results: Cough variant asthma (CVA) was recognized by 97.51% of physicians (1,166 respiratory specialists and 799 PCPs), followed by chest tightness variant asthma (CTVA, 83.72%) and occult asthma (73.54%). Specialists were more likely to follow diagnostic recommendations than PCPs (P < 0.01); however, 34.15% of physicians reported the utility of bronchodilation tests, airway provocation tests, and peak expiratory flow monitoring. A total of 91.70% and 92.01% of physicians prescribed inhaled corticosteroids (ICS) or ICS plus long-acting beta-agonists (LABA) for CVA and CTVA, respectively. Physicians prescribed an ICS or ICS/LABA for 4 (2-8) or 8 (4-12) weeks for CVA and 4 (2-8) or 5 (4-12) weeks for CTVA, and the prescription durations were significantly shorter for PCPs than for specialists (P < 0.01). Further, 52.42% and 35.78% reported good control of CVA and CTVA, respectively, with significantly lower control rates for PCPs than for specialists (P < 0.01). Additionally, specialists exhibited better assessment and educational habits than PCPs. Conclusion: While atypical asthma was identified by most specialists and PCPs, there remains a gap between management in real clinical practice and guideline recommendations, especially for PCPs. Further training of PCPs and clinical studies of atypical asthma are required to improve practice.

Therapeutic Effects of the Bcl-2 Inhibitor on Bleomycin-induced Pulmonary Fibrosis in Mice.

Idiopathic pulmonary fibrosis (IPF) is a distressing lung disorder with poor prognosis and high mortality rates. Limited therapeutic options for IPF is a major clinical challenge. Well-known for its anti-apoptotic properties, B-cell lymphoma 2 (Bcl-2) plays a critical role in the pathology of malignancies and inflammatory diseases, including IPF. In this study, we aimed to investigate the therapeutic effect of a Bcl-2 homology domain 3 mimetic inhibitor, ABT-199, on bleomycin (BLM)-induced pulmonary fibrosis in mice, and explore possible underlying mechanism. The lung inflammation and fibrosis model was established by intratracheal instillation of a single dose of BLM. We observed elevated Bcl-2 in the alveolar macrophages and fibroblasts derived from BLM-instilled mice from day 7. Further, we obtained in vivo evidence that early therapeutic treatment with Bcl-2 inhibitor ABT-199 from day 3, and late treatment from day 10, both alleviated airway inflammation and lung fibrosis induced by BLM. Our data suggest that ABT-199 might be an effective antifibrotic agent that interferes with profibrogenic cells, which may be a promising therapy in the treatment of clinical IPF patients.

Corrigendum: Autophagy Promotes Cigarette Smoke-Initiated and Elastin-Driven Bronchitis-Like Airway Inflammation in Mice.

[This corrects the article DOI: 10.3389/fimmu.2021.594330.].

Particulate matter exposure is highly correlated to pediatric asthma exacerbation.

Asthma is a heterogeneous disease in which environmental factors play an important role, and the effect of particulate matter (PM) on the occurrence and severity of asthma is drawing more attention. This study aims to identify the correlation between PM and pediatric asthma exacerbation and explore the potential mechanisms. The asthma visits data (N = 16,779,739) in a university-based tertiary children's hospital from January 2013 to December 2017 were collected, and the relationship between asthma visits and local PM concentration was analyzed. For further study, we established a house dust mite (HDM)-induced allergic airway inflammation model with PM intervention. We detected a correlation between PM concentration and pediatric asthma visits, especially in children under 6 years old. The in vivo data showed that PM aggravated HDM-induced airway inflammation, and IL-33 neutralizing antibody exerted a protective role. Our study suggests that PM is a risk factor in promoting pediatric asthma exacerbation, in which IL-33 might be a promising target.

IL-17-Mediated Inflammation Promotes Cigarette Smoke-Induced Genomic Instability.

(1) Background: Chronic inflammation has been regarded as a risk factor for the onset and progression of human cancer, but the critical molecular mechanisms underlying this pathological process have yet to be elucidated. (2) Methods: In this study, we investigated whether interleukin (IL)-17-mediated inflammation was involved in cigarette smoke-induced genomic instability. (3) Results: Higher levels of both IL-17 and the DNA damage response (DDR) were found in the lung tissues of smokers than in those of non-smokers. Similarly, elevated levels of IL-17 and the DDR were observed in mice after cigarette smoke exposure, and a positive correlation was observed between IL-17 expression and the DDR. In line with these observations, the DDR in the mouse lung was diminished in IL-17 KO when exposed to cigarette smoke. Besides this, the treatment of human bronchial epithelium cells with IL-17 led to increased levels of the DDR and chromosome breakage. (4) Conclusions: These results suggest that cigarette smoke induces genomic instability at least partially through IL-17-mediated inflammation, implying that IL-17 could play an important role in the development of lung cancer.

Epithelium-derived IL17A Promotes Cigarette Smoke-induced Inflammation and Mucus Hyperproduction.

The airway epithelium is a central modulator of innate and adaptive immunity in the lung. IL17A expression was found to be increased in the airway epithelium; however, the role of epithelium-derived IL17A in chronic obstructive pulmonary disease (COPD) remains unclear. In this study, we aimed to determine whether epithelium-derived IL17A regulates inflammation and mucus hyperproduction in COPD by using a cultured human bronchial epithelial (HBE) cell line in vitro and an airway epithelium IL17A-specific knockout mouse in vivo. Increased IL17A expression was observed in the mouse airway epithelium upon cigarette smoke (CS) exposure or in a mouse model of COPD that was induced by using CS and Eln (elastin). CS extract (CSE) also triggered IL17A expression in HBE cells. Blocking IL17A or IL17RA (IL17 receptor A) effectively attenuated CSE-induced MUC5AC and the inflammatory cytokines IL6, TNF-α, and IL1ß in HBE cells, suggesting that IL17A mediates CSE-induced inflammation and mucin production in an autocrine manner. CSE activated p-JUN (phospho-JUN) and p-JNK (phospho-c-Jun N-terminal kinase), which were also reduced by IL17RA siRNA, and JUN siRNA attenuated CSE-induced IL6 and MUC5AC. In vivo, selective knockout of IL17A in the airway epithelium markedly reduced the neutrophilic infiltration in BAL fluid, peribronchial inflammation, proinflammatory mediators (CXCL1 [CXC ligand 1] and CXCL2), and mucus production in a COPD mouse model. We showed a novel function of airway epithelium-derived IL17A, which can act locally in an autocrine manner to amplify inflammation and increase mucus production in COPD pathogenesis.

Application of a classifier combining bronchial transcriptomics and chest computed tomography features facilitates the diagnostic evaluation of lung cancer in smokers and nonsmokers.

Lung cancer screening by computed tomography (CT) reduces mortality but exhibited high false-positive rates. We established a diagnostic classifier combining chest CT features with bronchial transcriptomics. Patients with CT-detected suspected lung cancer were enrolled. The sample collected by bronchial brushing was used for RNA sequencing. The e1071 and pROC packages in R software was applied to build the model. Eventually, a total of 283 patients, including 183 with lung cancer and 100 with benign lesions, were included into final analysis. When incorporating transcriptomic data with radiological characteristics, the advanced model yielded 0.903 AUC with 81.1% NPV. Moreover, the classifier performed well regardless of lesion size, location, stage, histologic type or smoking status. Pathway analysis showed enhanced epithelial differentiation, tumor metastasis, and impaired immunity were predominant in smokers with cancer, whereas tumorigenesis played a central role in nonsmokers with cancer. Apoptosis and oxidative stress contributed critically in metastatic lung cancer; by contrast, immune dysfunction was pivotal in locally advanced lung cancer. Collectively, we devised a minimal-to-noninvasive, efficient diagnostic classifier for smokers and nonsmokers with lung cancer, which provides evidence for different mechanisms of cancer development and metastasis associated with smoking. A negative classifier result will help the physician make conservative diagnostic decisions.