Isolation and Purification of Epithelial and Endothelial Cells from Mouse Lung

Ulinastatin attenuated cardiac ischaemia/reperfusion injury by suppressing activation of the tissue kallikrein-kinin system

BACKGROUND AND PURPOSE

Ulinastatin has beneficial effects in patients undergoing coronary artery bypass grafting (CABG) surgery due to its anti-inflammatory properties, but the underlying mechanism remains unclear.

EXPERIMENTAL APPROACH

We used samples from patients undergoing CABG, a model of cardiac ischaemia-reperfusion injury (IRI) in mice and murine cardiac endothelial cell cultures to investigate links between ulinastatin, the kallikrein-kinin system (KKS), endothelial dysfunction and cardiac inflammation in the response to ischaemia/reperfusion injury (IRI). These links were assessed using clinical investigations, in vitro and in vivo experiments and RNA sequencing analysis.

KEY RESULTS

Ulinastatin inhibited the activity of tissue kallikrein, a key enzyme of the KKS, at 24 h after CABG surgery, which was verified in our murine cardiac ischaemia-reperfusion model. Under normal conditions, ulinastatin only inhibited kallikrein activity but did not affect bradykinin (B1/B2) receptors. Ulinastatin protected against IRI, in vivo and in vitro, by suppressing activation of the kallikrein-kinin system and down-regulating B1/B2 receptor-related signalling pathways including ERK/ iNOS, which resulted in enhanced endothelial barrier function, mitigation of inflammation and oedema, decreased infarct size, improved cardiac function and decreased mortality. Inhibition of kallikrein and knockdown of B1, but not B2 receptors prevented ERK translocation into the nucleus, reducing reperfusion-induced injury in murine cardiac endothelial cells.

CONCLUSIONS AND IMPLICATIONS

Treatment with ulinastatin exerts a protective influence on cardiac reperfusion by suppressing activation of the kallikrein-kinin system. Our findings highlight the potential of targeting kallikrein /bradykinin receptors to alleviate endothelial dysfunction, thus improving cardiac IRI.

A Virus-Inspired Inhalable Liponanogel Induces Potent Antitumor Immunity and Regression in Metastatic Lung Tumors

Pulmonary delivery of immunostimulatory agents such as poly(I:C) to activate double-stranded RNA sensors MDA5 and RIG-I within lung-resident antigen-presenting cells is a potential strategy to enhance antitumor immunity by promoting type I interferon secretion. Nevertheless, following pulmonary delivery, poly(I:C) suffers from rapid degradation and poor endosomal escape, thus limiting its potency. Inspired by the structure of a virus that utilizes internal viral proteins to tune the loading and cytosolic delivery of viral nucleic acids, we developed a liponanogel (LNG)-based platform to overcome the delivery challenges of poly(I:C). The LNG comprised an anionic polymer hyaluronic acid-based nanogel core coated by a lipid shell, which served as a protective layer to stabilize the nanogel core in the lungs. The nanogel core was protonated within acidic endosomes to enhance the endosomal membrane permeability and cytosolic delivery of poly(I:C). After pulmonary delivery, LNG-poly(I:C) induced 13.7-fold more IFNβ than poly(I:C) alone and two-fold more than poly(I:C) loaded in the state-of-art lipid nanoparticles [LNP-poly(I:C)]. Additionally, LNG-poly(I:C) induced more potent CD8+ T-cell immunity and stronger therapeutic effects than LNP-poly(I:C). The combination of LNG-poly(I:C) and PD-L1 targeting led to regression of established lung metastases. Due to the ease of manufacturing and the high biocompatibility of LNG, pulmonary delivery of LNG may be broadly applicable to the treatment of different lung tumors and may spur the development of innovative strategies for cancer immunotherapy. Significance: Pulmonary delivery of poly(I:C) with a virus-inspired inhalable liponanogel strongly activates cytosolic MDA5 and RIG-I and stimulates antitumor immunity, representing a promising strategy for safe and effective treatment of metastatic lung tumors.

Cold dispase digestion of murine lungs improves recovery and culture of airway epithelial cells

Airway epithelial cells (AECs) play a key role in maintaining lung homeostasis, epithelium regeneration and the initiation of pulmonary immune responses. To isolate and study murine AECs investigators have classically used short and hot (1h 37°C) digestion protocols. Here, we present a workflow for efficient AECs isolation and culture, utilizing long and cold (20h 4°C) dispase II digestion of murine lungs. This protocol yields a greater number of viable AECs compared to an established 1h 37°C dispase II digestion. Using a combination of flow cytometry and immunofluorescent microscopy, we demonstrate that compared to the established method, the cold digestion allows for recovery of a 3-fold higher number of CD45-CD31-EpCAM+ cells from murine lungs. Their viability is increased compared to established protocols, they can be isolated in larger numbers by magnetic-activated cell sorting (MACS), and they result in greater numbers of distal airway stem cell (DASC) KRT5+p63+ colonies in vitro. Our findings demonstrate that temperature and duration of murine lung enzymatic digestion have a considerable impact on AEC yield, viability, and ability to form colonies in vitro. We believe this workflow will be helpful for studying lung AECs and their role in the biology of lung.

BCG vaccination stimulates integrated organ immunity by feedback of the adaptive immune response to imprint prolonged innate antiviral resistance

Bacille Calmette-Guérin (BCG) vaccination can confer nonspecific protection against heterologous pathogens. However, the underlying mechanisms remain mysterious. We show that mice vaccinated intravenously with BCG exhibited reduced weight loss and/or improved viral clearance when challenged with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 B.1.351) or PR8 influenza. Protection was first evident between 14 and 21 d post-vaccination and lasted ∼3 months. Notably, BCG induced a biphasic innate response and robust antigen-specific type 1 helper T cell (TH1 cell) responses in the lungs. MyD88 signaling was essential for innate and TH1 cell responses, and protection against SARS-CoV-2. Depletion of CD4+ T cells or interferon (IFN)-γ activity before infection obliterated innate activation and protection. Single-cell and spatial transcriptomics revealed CD4-dependent expression of IFN-stimulated genes in lung myeloid and epithelial cells. Notably, BCG also induced protection against weight loss after mouse-adapted SARS-CoV-2 BA.5, SARS-CoV and SHC014 coronavirus infections. Thus, BCG elicits integrated organ immunity, where CD4+ T cells feed back on tissue myeloid and epithelial cells to imprint prolonged and broad innate antiviral resistance.

The IL-17A-neutrophil axis promotes epithelial cell IL-33 production during nematode lung migration

The early migratory phase of pulmonary helminth infections is characterized by tissue injury leading to the release of the alarmin interleukin (IL)-33 and subsequent induction of type 2 immune responses. We recently described a role for IL-17A, through suppression of interferon (IFN)-γ, as an important inducer of type 2 responses during infection with the lung-migrating rodent nematode Nippostrongylus brasiliensis. Here, we aimed to investigate the interaction between IL-17A and IL-33 during the early lung migratory stages of N. brasiliensis infection. In this brief report, we demonstrate that deficiency of IL-17A leads to impaired IL-33 expression and secretion early in infection, independent of IL-17A suppression of IFN-γ. Neutrophil-depletion experiments, which dramatically reduce lung injury, revealed that neutrophils are primarily responsible for the IL-17A-dependent release of IL-33 into the airways. Taken together, our results reveal an IL-17A-neutrophil-axis that can drive IL-33 during helminth infection, highlighting an additional pathway by which IL-17A regulates pulmonary type 2 immunity.

Sex-specific lung inflammation and mitochondrial damage in a model of electronic cigarette exposure in asthma

The prevalence of electronic cigarette (EC) use among adult with asthma has continued to increase over time, in part due to the belief of being less harmful than smoking. However, the extent of their toxicity and the involved mechanisms contributing to the deleterious impact of EC exposure on patients with preexisting asthma have not been delineated. In the present project, we tested the hypothesis that EC use contributes to respiratory damage and worsening inflammation in the lungs of patients with asthma. To define the consequences of EC exposure in established asthma, we used a mouse model with/without preexisting asthma for short-term exposure to EC aerosols. C57/BL6J mice were sensitized and challenged with a DRA (dust mite, ragweed, Aspergillus fumigates, 200 µg/mL) mixture and exposed daily to EC with nicotine (2% nicotine in 30:70 propylene glycol: vegetable glycerin) or filtered air for 2 wk. The mice were evaluated at 24 h after the final EC exposure. After EC exposure in asthmatic mice, lung inflammatory cell infiltration and goblet cell hyperplasia were increased, whereas EC alone did not cause airway inflammation. Our data also show that mitochondrial DNA (mtDNA) content and a key mtDNA regulator, mitochondrial transcription factor A (TFAM), are reduced in asthmatic EC-exposed mice in a sex-dependent manner. Together, these results indicate that TFAM loss in lung epithelium following EC contributes to male-predominant sex pathological differences, including mitochondrial damage, inflammation, and remodeling in asthmatic airways.NEW & NOTEWORTHY Respiratory immunity is dysregulated in preexisting asthma, and further perturbations by EC use could exacerbate asthma severity. However, the extent of their toxicity and the involved mechanisms contributing to the deleterious impact of EC exposure on patients with preexisting asthma have not been delineated. We found that EC has unique biological impacts in lungs and potential sex differences with loss of TFAM, a key mtDNA regulator, in lung epithelial region from our animal EC study.

Glucocorticoids are differentially synthesized along the murine and human respiratory tree

BACKGROUND

Synthetic glucocorticoids (GC) are effective in the treatment of inflammatory diseases of the lung. However, long-term use leads to severe side effects. Endogenous GC can be synthesized locally, either de novo from cholesterol in a 11β-hydroxylase (Cyp11b1)-dependent manner, or by reactivation from 11-dehydrocorticosterone/cortisone by 11β-hydroxysteroid dehydrogenase 1 (Hsd11b1). We aimed to define the molecular pathways of endogenous GC synthesis along the respiratory tree to provide a basis for understanding how local GC synthesis contributes to tissue homeostasis.

METHODS

Expression of steroidogenic enzymes in murine lung epithelium was analyzed by macroscopic and laser capture microdissection, followed by RT-qPCR. Flow cytometry analysis was performed to identify the cellular source of steroidogenic enzymes. Additionally, the induction of steroidogenic enzyme expression in the lung was analyzed after lipopolysaccharide (LPS) injection. mRNA and protein expression of steroidogenic enzymes was confirmed in human lung tissue by RT-qPCR and immunohistochemistry. Furthermore, GC synthesis was examined in ex vivo cultures of fresh tissue from mice and human lobectomy patients.

RESULTS

We observed that the murine and human lung tissue differentially expresses synthesis pathway-determining enzymes along the respiratory tree. We detected Hsd11b1 expression in bronchial, alveolar, club and basal epithelial cells, whereas Cyp11b1 expression was detectable only in tracheal epithelial cells of mice. Accordingly, de novo synthesis of bioactive GC occurred in the large conducting airways, whereas reactivation occurred everywhere along the respiratory tree. Strikingly, Cyp11b1 but not Hsd11b1 expression was enhanced in the trachea upon LPS injection in mice.

CONCLUSION

We report here the differential synthesis of bioactive GC along the murine and human respiratory tree. Thus, extra-adrenal de novo GC synthesis and reactivation may differentially contribute to the regulation of immunological and inflammatory processes in the lung.

Comparison between sevoflurane and propofol on immunomodulation in an in vitro model of sepsis

Introduction

Patients with sepsis often require sedation and/or anesthesia. Although the immunomodulatory effects of anesthetics have been increasingly recognized, the molecular mechanisms require better elucidation. We compared the effects of sevoflurane with propofol on the expression of pro- and anti-inflammatory biomarkers released by monocytes/macrophages and blood/bronchoalveolar lavage fluid (BALF) neutrophils, the phagocytic capacity of monocytes/ macrophages, and neutrophil migration, as well as mediators associated with alveolar epithelial and endothelial cells obtained from rats with sepsis.

Methods

Polymicrobial sepsis was induced by cecal ligation and puncture in nine male Wistar rats. After 48 h, animals were euthanized and their monocytes/alveolar macrophages, blood and BALF neutrophils, as well as alveolar epithelial and endothelial cells were extracted, and then exposed to (1) sevoflurane (1 minimal alveolar concentration), (2) propofol (50 μM), or (3) saline, control (CTRL) for 1 h.

Results

Sevoflurane reduced interleukin (IL)-6 mRNA expression in monocytes and alveolar macrophages (p = 0.007, p = 0.029), whereas propofol decreased IL-6 mRNA only in alveolar macrophages (p = 0.027) compared with CTRL. Sevoflurane increased IL-10 expression (p = 0.0002) in monocytes compared with propofol and increased IL-10 mRNA and transforming growth factor (TGF)-β mRNA (p = 0.037, p = 0.045) compared with CTRL. Both sevoflurane and propofol did not affect mRNA expression of IL-10 and TGF-β in alveolar macrophages. The phagocytic capacity of monocytes (p = 0.0006) and alveolar macrophages (p = 0.0004) was higher with sevoflurane compared with propofol. Sevoflurane, compared with CTRL, reduced IL-1β mRNA (p = 0.003, p = 0.009) and C-X-C chemokine receptor 2 mRNA (CXCR2, p = 0.032 and p = 0.042) in blood and BALF neutrophils, and increased CXCR4 mRNA only in BALF neutrophils (p = 0.004). Sevoflurane increased blood neutrophil migration (p = 0.015) compared with propofol. Both sevoflurane and propofol increased zonula occludens-1 mRNA (p = 0.046, p = 0.003) in alveolar epithelial cells and reduced Toll-like receptor 4 mRNA (p = 0.043, p = 0.006) in alveolar endothelial cells compared with CTRL. Only propofol reduced surfactant protein B mRNA (p = 0.028) in alveolar epithelial cells.

Discussion

Sevoflurane, compared with propofol, increased anti-inflammatory biomarkers in monocytes, but not in alveolar macrophages, enhanced monocyte/alveolar macrophage phagocytic capacity and increased neutrophil migration in in vitro experimental sepsis. Both propofol and sevoflurane protected lung epithelial and endothelial cells.

25-Hydroxycholesterol exacerbates vascular leak during acute lung injury

Cholesterol-25-hydroxylase (CH25H), the biosynthetic enzyme for 25-hydroxycholesterol (25HC), is most highly expressed in the lung, but its role in lung biology is poorly defined. Recently, we reported that Ch25h is induced in monocyte-derived macrophages recruited to the airspace during resolution of lung inflammation and that 25HC promotes liver X receptor-dependent (LXR-dependent) clearance of apoptotic neutrophils by these cells. Ch25h and 25HC are, however, also robustly induced by lung-resident cells during the early hours of lung inflammation, suggesting additional cellular sources and targets. Here, using Ch25h-/- mice and exogenous 25HC in lung injury models, we provide evidence that 25HC sustains proinflammatory cytokines in the airspace and augments lung injury, at least in part, by inducing LXR-independent endoplasmic reticulum stress and endothelial leak. Suggesting an autocrine effect in endothelium, inhaled LPS upregulates pulmonary endothelial Ch25h, and non-hematopoietic Ch25h deletion is sufficient to confer lung protection. In patients with acute respiratory distress syndrome, airspace 25HC and alveolar macrophage CH25H were associated with markers of microvascular leak, endothelial activation, endoplasmic reticulum stress, inflammation, and clinical severity. Taken together, our findings suggest that 25HC deriving from and acting on different cell types in the lung communicates distinct, temporal LXR-independent and -dependent signals to regulate inflammatory homeostasis.

Protocol to dissociate healthy and infected murine- and hamster-derived lung tissue for single-cell transcriptome analysis

In infectious disease research, single-cell RNA sequencing allows dissection of host-pathogen interactions. As a prerequisite, we provide a protocol to transform solid and complex organs such as lungs into representative diverse, viable single-cell suspensions. Our protocol describes performance of vascular perfusion, pneumonectomy, enzymatic digestion, and mechanical dissociation of lung tissue, as well as red blood cell lysis and counting of isolated cells. A challenge remains, however, to further increase the proportion of pulmonary endothelial cells without compromising on viability. For complete details on the use and execution of this protocol, please refer to Nouailles et al. (2021),1 Wyler et al. (2022),2 and Ebenig et al. (2022).3.

An Innate Checkpoint Determines Immune Dysregulation and Immunopathology during Pulmonary Murine Coronavirus Infection

Hallmarks of life-threatening, coronavirus-induced disease include dysregulated antiviral immunity and immunopathological tissue injury. Nevertheless, the sampling of symptomatic patients overlooks the initial inflammatory sequela culminating in severe coronavirus-induced disease, leaving a fundamental gap in our understanding of the early mechanisms regulating anticoronavirus immunity and preservation of tissue integrity. In this study, we delineate the innate regulators controlling pulmonary infection using a natural mouse coronavirus. Within hours of infection, the cellular landscape of the lung was transcriptionally remodeled altering host metabolism, protein synthesis, and macrophage maturation. Genetic perturbation revealed that these transcriptional programs were type I IFN dependent and critically controlled both host cell survival and viral spread. Unrestricted viral replication overshooting protective IFN responses culminated in increased IL-1β and alarmin production and triggered compensatory neutrophilia, interstitial inflammation, and vascular injury. Thus, type I IFNs critically regulate early viral burden, which serves as an innate checkpoint determining the trajectory of coronavirus dissemination and immunopathology.

Ablation of Adar1 in myeloid cells imprints a global antiviral state in the lung and heightens early immunity against SARS-CoV-2

Under normal homeostatic conditions, self-double-stranded RNA (self-dsRNA) is modified by adenosine deaminase acting on RNA 1 (ADAR1) to prevent the induction of a type I interferon-mediated inflammatory cascade. Antigen-presenting cells (APCs) sense pathogen-associated molecular patterns, such as dsRNA, to activate the immune response. The impact of ADAR1 on the function of APCs and the consequences to immunity are poorly understood. Here, we show that ADAR1 deletion in CD11c+ APCs leads to (1) a skewed myeloid cell compartment enriched in inflammatory cDC2-like cells, (2) enhanced numbers of activated tissue resident memory T cells in the lung, and (3) the imprinting of a broad antiviral transcriptional signature across both immune and non-immune cells. The resulting changes can be partially reversed by blocking IFNAR1 signaling and promote early resistance against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Our study provides insight into the consequences of self-dsRNA sensing in APCs on the immune system.

Metabolic labeling of cardiomyocyte-derived small extracellular-vesicle (sEV) miRNAs identifies miR-208a in cardiac regulation of lung gene expression

Toxoplasma gondii uracil phosphoribosyltransferase (UPRT) converts 4-thiouracil (4TUc) into 4-thiouridine (4TUd), which is incorporated into nascent RNAs and can be biotinylated, then labelled with streptavidin conjugates or isolated via streptavidin-affinity methods. Here, we generated mice that expressed T. gondii UPRT only in cardiomyocytes (CM UPRT mice) and tested our hypothesis that CM-derived miRNAs (CM miRs) are transferred into remote organs after myocardial infarction (MI) by small extracellular vesicles (sEV) that are released from the heart into the peripheral blood (PB sEV). We found that 4TUd was incorporated with high specificity and sensitivity into RNAs isolated from the hearts and PB sEV of CM UPRT mice 6 h after 4TUc injection. In PB sEV, 4TUd was incorporated into CM-specific/enriched miRs including miR-208a, but not into miRs with other organ or tissue-type specificities. 4TUd-labelled miR208a was also present in lung tissues, especially lung endothelial cells (ECs), and CM-derived miR-208a (CM miR-208a) levels peaked 12 h after experimentally induced MI in PB sEV and 24 h after MI in the lung. Notably, miR-208a is expressed from intron 29 of α myosin heavy chain (αMHC), but αMHC transcripts were nearly undetectable in the lung. When PB sEV from mice that underwent MI (MI-PB sEV) or sham surgery (Sham-PB sEV) were injected into intact mice, the expression of Tmbim6 and NLK, which are suppressed by miR-208a and cooperatively regulate inflammation via the NF-κB pathway, was lower in the lungs of MI-PB sEV-treated animals than the lungs of animals treated with Sham-PB sEV or saline. In MI mice, Tmbim6 and NLK were downregulated, whereas endothelial adhesion molecules and pro-inflammatory cells were upregulated in the lung; these changes were significantly attenuated when the mice were treated with miR-208a antagomirs prior to MI surgery. Thus, CM UPRT mice enables us to track PB sEV-mediated transport of CM miRs and identify an miR-208a-mediated mechanism by which myocardial injury alters the expression of genes and inflammatory response in the lung.

CLEC5A is critical in Pseudomonas aeruginosa-induced acute lung injury

Pseudomonas aeruginosa is one of the most common nosocomial infections worldwide, and it frequently causes ventilator-associated acute pneumonia in immunocompromised patients. Abundant neutrophil extracellular traps (NETs) contribute to acute lung injury, thereby aggravating ventilator-induced lung damage. While pattern recognition receptors (PRRs) TLR4 and TLR5 are required for host defense against P. aeruginosa invasion, the PRR responsible for P. aeruginosa–induced NET formation, proinflammatory cytokine release, and acute lung injury remains unclear. We found that myeloid C-type lectin domain family 5 member A (CLEC5A) interacts with LPS of P. aeruginosa and is responsible for P. aeruginosa–induced NET formation and lung inflammation. P. aeruginosa activates CLEC5A to induce caspase-1–dependent NET formation, but it neither causes gasdermin D (GSDMD) cleavage nor contributes to P. aeruginosa–induced neutrophil death. Blockade of CLEC5A attenuates P. aeruginosa–induced NETosis and lung injury, and simultaneous administration of anti-CLEC5A mAb with ciprofloxacin increases survival rate and decreases collagen deposition in the lungs of mice challenged with a lethal dose of P. aeruginosa. Thus, CLEC5A is a promising therapeutic target to reduce ventilator-associated lung injury and fibrosis in P. aeruginosa–induced pneumonia.

Monitoring in vivo behavior of size-dependent fluorescent particles as a model fine dust

Background

There has been growing concern regarding the impact of air pollution, especially fine dust, on human health. However, it is difficult to estimate the toxicity of fine dust on the human body because of its diverse effects depending on the composition and environmental factors.

Results

In this study, we focused on the difference in the biodistribution of fine dust according to the size distribution of particulate matter after inhalation into the body to predict its impact on human health. We synthesized Cy7-doped silica particulate matters (CSPMs) having different particle sizes and employed them as model fine dust, and studied their whole-body in vivo biodistribution in BALB/c nude mice. Image-tracking and quantitative and qualitative analyses were performed on the ex vivo organs and tissues. Additionally, flow cytometric analysis of single cells isolated from the lungs was performed. Smaller particles with a diameter of less than 100 nm (CSPM0.1) were observed to be removed relatively rapidly from the lungs upon initial inhalation. However, they were confirmed to accumulate continuously over 4 weeks of observation. In particular, smaller particles were found to spread rapidly to other organs during the early stages of inhalation.

Conclusions

The results show in vivo behavioral differences that arisen from particle size through mouse experimental model. Although these are far from the human inhalation studies, it provides information that can help predict the effect of fine dust on human health. This study might provide with insights on association between CSPM0.1 accumulation in several organs including the lungs and adverse effect to underlying diseases in the organs.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01419-4.

lincRNA-Cox2 Functions to Regulate Inflammation in Alveolar Macrophages during Acute Lung Injury

Our respiratory system is vital to protect us from the surrounding nonsterile environment; therefore, it is critical for a state of homeostasis to be maintained through a balance of inflammatory cues. Recent studies have shown that actively transcribed noncoding regions of the genome are emerging as key regulators of biological processes, including inflammation. lincRNA-Cox2 is one such example of an inflammatory inducible long intergenic noncoding RNA functioning to fine-tune immune gene expression. Using bulk and single-cell RNA sequencing, in addition to FACS, we find that lincRNA-Cox2 is most highly expressed in the lung and is most upregulated after LPS-induced lung injury (acute lung injury [ALI]) within alveolar macrophages, where it functions to regulate inflammation. We previously reported that lincRNA-Cox2 functions to regulate its neighboring protein Ptgs2 in cis, and in this study, we use genetic mouse models to confirm its role in regulating gene expression more broadly in trans during ALI. Il6, Ccl3, and Ccl5 are dysregulated in the lincRNA-Cox2-deficient mice and can be rescued to wild type levels by crossing the deficient mice with our newly generated lincRNA-Cox2 transgenic mice, confirming that this gene functions in trans. Many genes are specifically regulated by lincRNA-Cox2 within alveolar macrophages originating from the bone marrow because the phenotype can be reversed by transplantation of wild type bone marrow into the lincRNA-Cox2-deficient mice. In conclusion, we show that lincRNA-Cox2 is a trans-acting long noncoding RNA that functions to regulate immune responses and maintain homeostasis within the lung at baseline and on LPS-induced ALI.

Protocols for endothelial cell isolation from mouse tissues: brain, choroid, lung, and muscle

Endothelial cells (ECs) harbor distinct phenotypical and functional characteristics depending on their tissue localization and contribute to brain, eye, lung, and muscle diseases such as dementia, macular degeneration, pulmonary hypertension, and sarcopenia. To study their function, isolation of pure ECs in high quantities is crucial. Here, we describe protocols for rapid and reproducible blood vessel EC purification established for scRNA sequencing from murine tissues using mechanical and enzymatic digestion followed by magnetic and fluorescence-activated cell sorting. For complete details on the use and execution of these protocol, please refer to Kalucka et al. (2020), Rohlenova et al. (2020), and Goveia et al. (2020).

Mitochondria-Rich Fraction Isolated From Mesenchymal Stromal Cells Reduces Lung and Distal Organ Injury in Experimental Sepsis

OBJECTIVES

To ascertain whether systemic administration of mitochondria-rich fraction isolated from mesenchymal stromal cells would reduce lung, kidney, and liver injury in experimental sepsis.

DESIGN

Animal study.

SETTING

Laboratory investigation.

SUBJECTS

Sixty C57BL/6 male mice.

INTERVENTIONS

Sepsis was induced by cecal ligation and puncture; sham-operated animals were used as control. At 24 hours after surgery, cecal ligation and puncture and Sham animals were further randomized to receive saline or mitochondria-rich fraction isolated from mesenchymal stromal cells (3 × 106) IV. At 48 hours, survival, peritoneal bacterial load, lung, kidney, and liver injury were analyzed. Furthermore, the effects of mitochondria on oxygen consumption rate and reactive oxygen species production of lung epithelial and endothelial cells were evaluated in vitro.

MEASUREMENTS AND MAIN RESULTS

In vitro exposure of lung epithelial and endothelial cells from cecal ligation and puncture animals to mitochondria-rich fraction isolated from mesenchymal stromal cells restored oxygen consumption rate and reduced total reactive oxygen species production. Infusion of exogenous mitochondria-rich fraction from mesenchymal stromal cells (mitotherapy) reduced peritoneal bacterial load, improved lung mechanics and histology, and decreased the expression of interleukin-1β, keratinocyte chemoattractant, indoleamine 2,3-dioxygenase-2, and programmed cell death protein 1 in lung tissue, while increasing keratinocyte growth factor expression and survival rate in cecal ligation and puncture-induced sepsis. Mitotherapy also reduced kidney and liver injury, plasma creatinine levels, and messenger RNA expressions of interleukin-18 in kidney, interleukin-6, indoleamine 2,3-dioxygenase-2, and programmed cell death protein 1 in liver, while increasing nuclear factor erythroid 2-related factor-2 and superoxide dismutase-2 in kidney and interleukin-10 in liver.

CONCLUSIONS

Mitotherapy decreased lung, liver, and kidney injury and increased survival rate in cecal ligation and puncture-induced sepsis.

Endothelial Aryl Hydrocarbon Receptor Nuclear Translocator Mediates the Angiogenic Response to Peripheral Ischemia in Mice With Type 2 Diabetes Mellitus

Hypoxia-inducible factors (HIFs) are the master regulators of angiogenesis, a process that is impaired in patients with diabetes mellitus (DM). The transcription factor aryl hydrocarbon receptor nuclear translocator (ARNT, also known as HIF1β) has been implicated in the development and progression of diabetes. Angiogenesis is driven primarily by endothelial cells (ECs), but both global and EC-specific loss of ARNT-cause are associated with embryonic lethality. Thus, we conducted experiments in a line of mice carrying an inducible, EC-specific ARNT-knockout mutation (Arnt Δ EC, ERT2) to determine whether aberrations in ARNT expression might contribute to the vascular deficiencies associated with diabetes. Mice were first fed with a high-fat diet to induce diabetes. Arnt Δ EC, ERT2 mice were then adminstrated with oral tamoxifen to disrupt Arnt and peripheral angiogenesis was evaluated by using laser-Doppler perfusion imaging to monitor blood flow after hindlimb ischemia. The Arnt Δ EC, ERT2 mice had impaired blood flow recovery under both non-diabetic and diabetic conditions, but the degree of impairment was greater in diabetic animals. In addition, siRNA-mediated knockdown of ARNT activity reduced measurements of tube formation, and cell viability in human umbilical vein endothelial cells (HUVECs) cultured under high-glucose conditions. The Arnt Δ EC, ERT2 mutation also reduced measures of cell viability, while increasing the production of reactive oxygen species (ROS) in microvascular endothelial cells (MVECs) isolated from mouse skeletal muscle, and the viability of Arnt Δ EC, ERT2 MVECs under high-glucose concentrations increased when the cells were treated with an ROS inhibitor. Collectively, these observations suggest that declines in endothelial ARNT expression contribute to the suppressed angiogenic phenotype in diabetic mice, and that the cytoprotective effect of ARNT expression in ECs is at least partially mediated by declines in ROS production.

UDP-glucose and P2Y14 receptor amplify allergen-induced airway eosinophilia

Airway eosinophilia is a hallmark of allergic asthma and is associated with mucus production, airway hyperresponsiveness, and shortness of breath. Although glucocorticoids are widely used to treat asthma, their prolonged use is associated with several side effects. Furthermore, many individuals with eosinophilic asthma are resistant to glucocorticoid treatment, and they have an unmet need for novel therapies. Here, we show that UDP-glucose (UDP-G), a nucleotide sugar, is selectively released into the airways of allergen-sensitized mice upon their subsequent challenge with that same allergen. Mice lacking P2Y14R, the receptor for UDP-G, had decreased airway eosinophilia and airway hyperresponsiveness compared with wild-type mice in a protease-mediated model of asthma. P2Y14R was dispensable for allergic sensitization and for the production of type 2 cytokines in the lung after challenge. However, UDP-G increased chemokinesis in eosinophils and enhanced their response to the eosinophil chemoattractant, CCL24. In turn, eosinophils triggered the release of UDP-G into the airway, thereby amplifying eosinophilic recruitment. This positive feedback loop was sensitive to therapeutic intervention, as a small molecule antagonist of P2Y14R inhibited airway eosinophilia. These findings thus reveal a pathway that can be therapeutically targeted to treat asthma exacerbations and glucocorticoid-resistant forms of this disease.

Resveratrol improves Gly-LDL-induced vascular endothelial cell apoptosis, inflammatory factor secretion and oxidative stress by regulating miR-142-3p and regulating SPRED2-mediated autophagy

BACKGROUND

Resveratrol improves cell apoptosis and tissue damage induced by high glucose, but the specific mechanism is unknown.

METHODS

This is a basic research. We performed cell transfection, real-time fluorescence quantitative PCR (qPCR), flow cytometry, immunofluorescence, western blot, enzyme linked immunosorbent assay (ELISA) and cell viability assay to analyze cell viability, cell cycle, cellular oxidative stress, intracellular inflammatory factors and autophagy activities in vitro. Meanwhile, dual luciferase reporter assay was conducted to explore the influence of miR-142-3p and sprouty-related EVH1 domain 2 (SPRED 2) on human glycated low-density lipoprotein (Gly-LDL)-induced vascular endothelial cell apoptosis, inflammatory factor secretion and oxidative stress.

RESULTS

Resveratrol inhibited the expression of miR-142-3p in human umbilical vein endothelial cells (HUVECs) induced by Gly-LDL in a dose-dependent manner, and the overexpression of miR-142-3p reverses the effect of resveratrol on the proliferation, apoptosis, secretion of inflammatory factors, oxidative stress, and autophagy. The dual-luciferase report analysis found a negative regulatory relationship between miR-142-3p and SPRED2. Inhibition of SPRED2 reversed the effects of resveratrol on Gly-LDL-induced HUVECs proliferation, apoptosis, inflammatory factor secretion and oxidative stress, and reversed the effects of resveratrol on Gly-LDL-induced HUVECs autophagy.

CONCLUSION

miR-142-3p promotes the development of diabetes by inhibiting SPRED2-mediated autophagy, including inducing cell apoptosis, aggravating cellular oxidative stress and secretion of inflammatory factors, and resveratrol improves this effect.

Comprehensive phenotyping of endothelial cells using flow cytometry 1: Murine

The endothelium forms a selective barrier between circulating blood or lymph and surrounding tissue. Endothelial cells play an essential role in vessel homeostasis, and identification of these cells is critical in vascular biology research. However, characteristics of endothelial cells differ depending on the location and type of blood or lymph vessel. Endothelial cell subsets are numerous and often identified using different flow cytometric markers, making immunophenotyping these cells complex. In part 1 of this two part review series, we present a comprehensive overview of markers for the flow cytometric identification and phenotyping of murine endothelial subsets. These subsets can be distinguished using a panel of cell surface and intracellular markers shared by all endothelial cells in combination with additional markers of specialized endothelial cell types. This review can be used to determine the best markers for identifying and phenotyping desired murine endothelial cell subsets.

SARS-CoV-2, testosterone and frailty in males (PROTEGGIMI): A multidimensional research project

Preliminary published data depict a much greater prevalence of males with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) referred for intensive care unit admission and severe sequelae in several countries. In this context, males seem to not only be more susceptible to the infection compared to female subjects, at least in Western countries, but their case fatality rate attributable to SARS-CoV-2 infection is also highest. Therefore, we may speculate that the different hormonal milieu could have a more profound pathophysiological role in association with SARS-CoV-2, with endogenous testosterone leaving men more prone to develop more serious complications related to the SARS-CoV-2 infection. Another option is that SARS-CoV-2 infection per se causes an acute stage of male hypogonadism, the depletion of androgenic action triggering serious or an even fatal course of the disease. Therefore, we strongly advocate the development of a prospective multidimensional andrological translational research project in men, which we called the PROTEGGIMI study. In this Opinion Article, we will not only highlight novel research activity in this area but also invite other researchers and learned scientific societies to join us in our efforts to understand an important and very newly discovered gap in knowledge, which may have serious implications for the lives of millions of men.