Induced Regulatory T Cells Attenuate Poly I:C\u2010Triggered Acute Lung Injury by Modulating Cytokine Responses

Mouse-Passaged Severe Acute Respiratory Syndrome-Associated Coronavirus Leads to Lethal Pulmonary Edema and Diffuse Alveolar Damage in Adult but Not Young Mice

Endoplasmic reticulum stress is involved in ventilator-induced lung injury in mice via the IRE1α-TRAF2-NF-κB pathway

Acute lung injury (ALI) is often characterized by severe lung inflammation and pulmonary edema with poor gas exchange and hypoxemia. Alveolar inflammation and water flooding are, in fact, notable features of ALI pathogenesis. The sodium-potassium-chloride co-transporter isoform 1 (NKCC1), localized at the basolateral surface of the lung epithelium, drives water transport via back transport of Na+ and Cl− to the alveolar air space. NKCC1, therefore, is crucial in regulating alveolar fluid. Increased expression of NKCC1 results in increased alveolar fluid secretion and impaired alveolar fluid clearance. During ALI, the with no lysine kinase (WNK), oxidative stress responsive kinase 1 (OSR1), and STE20/SPS1-related proline/alanine-rich kinase (SPAK) pathways are activated, which upregulates NKCC1 expression. Proinflammatory cytokines also enhance the expression of NKCC1 via c-Jun N-terminal kinase-and p38-dependent pathways. NKCC1 activation also increases the expression of proinflammatory cytokines via cell rupture and activation of macrophages. Increased proinflammatory cytokines, in turn, recruit inflammatory cells to the site of injury and cause further lung damage. Animals with high expression of NKCC1 show more severe lung injury with presentations of more severe pulmonary edema and microvascular permeability, higher expression of proinflammatory cytokines, and greater neutrophilic infiltration. In contrast, animals with low expression of NKCC1 or those treated with NKCC1 inhibitors show less severe lung injury with milder levels of presentations of ALI. These reports collectively highlight a novel role of NKCC1 in ALI pathogenesis. Manipulation of NKCC1 expression levels could, therefore, represent novel modalities for effective ALI treatment.

A novel rabbit model of severe ARDS: Synergistic effects of acid aspiration and harmful mechanical ventilation.

The article contains sections titled: Toxic Effects and Mode of Action Mechanism of Action Toxicokinetics and Metabolism Effects in Humans Animal Experiments and in vitro Studies Acute toxicity Subacute, subchronic and chronic toxicity Local effects on skin and mucous membranes Allergenic effects Reproductive toxicity Genotoxicity Carcinogenicity Manifesto (MAK Value, Classification)

Ozone exposure promotes pyroptosis in rat lungs via the TLR2/4-NF-κB-NLRP3 signaling pathway

BackgroundThe currently available treatment methods are ineffective in reducing mortality or improving outcomes in acute lung injury (ALI). The activation of protein kinase C alpha (PKCα) has recently been implicated in ALI development. We explored the potential therapeutic outcomes of PKCα inhibition in cases of ALI and to elucidate the related mechanisms.MethodsIndexes of lung inflammation and injury were examined in lipopolysaccharide (LPS)-treated C57BL/6J mice (male) and macrophages after pretreatment with a PKCα inhibitor. Tissues were collected to assess lung injury by hematoxylin and eosin (H&E) staining. Bronchoalveolar lavage fluid was used to measure the pulmonary edema, hyperinflammatory response, and oxidative stress by bicinchoninic acid (BCA) method and enzyme-linked immunosorbent assay (ELISA). We tested the effect of PKCα inhibition on LPS-induced proliferation, cytotoxicity, oxidative damage, and the release of inflammatory cytokines in macrophages using the Cell Counting Kit-8 (CCK-8) and lactate dehydrogenase (LDH) cytotoxicity assay kit, flow cytometry, quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and ELISA. The nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway related proteins were detected by Western blot, immunohistochemistry (IHC), and immunofluorescence staining.ResultsWe observed that LPS upregulated PKCα phosphorylation, induced a hyperinflammatory response, and caused lung injury. However, PKCα inhibition effectively attenuated the changes caused by LPS. Moreover, we confirmed that inhibiting PKCα weakened the activity of the NF-κB pathway under LPS-induced ALI. These findings indicated that inhibition of PKCα is protective against LPS-induced hyperinflammatory response in ALI, this effect is likely to attributed to the downregulation of NF-κB signaling pathways.ConclusionsThe results showed that PKCα inhibition could attenuate ALI which may closely related to its anti-inflammatory and anti-oxidative effects.

Although overexpression of vascular endothelial growth factor (VEGF) 165 in the lung causes pulmonary oedema, its role in human acute lung injury (ALI) is unclear. VEGF levels are reported to be lower in bronchoalveolar lavage from ALI patients compared with normals, but these studies did not include a comparably ill control group with noninflammatory pulmonary oedema. The current authors hypothesised that VEGF levels in pulmonary oedema fluid would be lower in ALI patients compared with control patients with severe hydrostatic pulmonary oedema. VEGF was measured in pulmonary oedema fluid and plasma from 56 patients with ALI and 46 controls with severe hydrostatic pulmonary oedema. Pulmonary oedema fluid levels of VEGF did not differ between patients with hydrostatic oedema (median 799 pg x mL(-1), interquartile range (IQR) 226-2,281) and ALI (median 507, IQR 0.8-1,031). Plasma levels were also the same (median 20.5 pg x mL(-1), IQR 0-152 versus 4.8, IQR 0-99.8). There was no association between plasma or oedema fluid VEGF levels and outcomes including mortality. Vascular endothelial growth factor levels in pulmonary oedema fluid were depressed both in acute lung injury and hydrostatic pulmonary oedema. The decrease in air space concentrations of vascular endothelial growth factor in acute lung injury may not be a function of the degree of lung injury, but rather may result from alveolar flooding.

Acute exposure to hyperoxia results in well-described pathophysiologic responses in the lungs, beginning with subtle, subcellular changes and ending with severe pulmonary inflammation and edema. The biologic events that underlie or accompany this injury are not well understood. Our previous studies in rabbits have shown that hyperoxia induces large increases in the mRNAs encoding metallothionein (MT) and the tissue inhibitor of metalloproteinases (TIMP-I). Here we report studies of hyperoxic lung injury in two strains of mouse that differ in their relative resistance to O2 toxicity. O2-sensitive (C57BL/6J) mice and O2-resistant (C3H/HeJ) mice were exposed to 100% O2 for up to 96 h. Lung mRNAs were assayed by primer extension and slot blot hybridization. By 72 h of hyperoxia, the sensitive strain showed large increases in MT-I, MT-II, and TIMP-I mRNAs. The resistant strain showed similar changes but with a 24-h delay. In situ hybridization demonstrated that hyperoxic lung injury was accompanied by obvious increases in TIMP-I and MT transcripts in cells surrounding arteries and large airways, where many inflammatory cells were localized. With prolonged exposure, hybridization to MT transcripts had spread throughout lung parenchyma. The two strains showed the same patterns of in situ hybridization for TIMP-I and MT transcripts but, as with the whole lung homogenates, followed a different time course. Corresponding increases in MT protein were shown to occur, using a cadmium binding assay and by immunohistochemistry. The strong spatial correlation between the presence of localized inflammation and increased TIMP-I and MT expression further supports the importance of TIMP-I and MT in acute lung injury.

Lung injury is a frequent consequence of O2 therapy administered to newborn and adults with respiratory distress and results in important mortality and morbidity. Acute exposure to hyperoxia results in a well-described pathophysiologic response, beginning with subtle, subcellular changes and ending with severe pulmonary inflammation and edema. The appearance of neutrophils is associated with marked accentuation of lung injury. Platelet/endothelial cell adhesion molecule 1 (PECAM-1), a member of the immunoglobulin superfamily that is expressed at the junctions between endothelial cells, is essential to the transendothelial migration of leukocytes. Alternative splicing of the cytoplasmic domain of PECAM-1 mRNA has been documented in vivo during embryonic heart development and has been shown to produce modification in ligand properties in vitro. We have previously shown an increase of PECAM-1 expression in the endothelium of lung exposed to hyperoxia. In this study, PECAM isoform expression was studied in lung of adult male mice exposed to hyperoxia up to 96h. Whole-lung RNA from controls and hyperoxia-exposed animals were reversed transcribed (RT) and amplified by polymerase chain reaction (PCR) using primer pairs that flank the cytoplasmic domain. The down-stream primer was labeled with P32 and the PCR products were separated on polycrylamide gels before autoradiography. At least 7 isoforms of PECAM-1 were detected in lung of control mice with a predominance of a middle size isoform; the isoform with the full length cytoplasmic domain accounted for less than 20% of the total PECAM-1 mRNA. No additional isoform was seen following hyperoxia, but a variations in the abundance of each isoforms was observed. Characterization of the isoforms are underway. The biological significance of the alternative splicing of PECAM-1 mRNA is still unknown, however the demonstration of isoform specific regulation suggest that its role is not restricted to organ development(Quebec Pulmonary Association, Queen Elizabeth II Research fund, Telethon de la Recherche sur les Maladies Infantiles).

Ferrostatin-1 alleviates ventilator-induced lung injury by inhibiting ferroptosis

Sepsis associated acute respiratory distress syndrome (ARDS), is a life-threatening condition characterized by severe pulmonary inflammation. Previous research has suggested that allergic immune diseases are associated with a lower risk of sepsis. Therefore, we hypothesized that certain molecules involved in type 2 inflammation are beneficial for the outcome of sepsis associated ARDS. Thymic stromal lymphopoietin (TSLP) is known to promote Th2 responses in allergic disease, however, its role in sepsis associated ARDS remains limited. To investigate the role of TSLP in sepsis associated lung injury, we administered exogenous recombinant TSLP to wild-type mice, followed by lipopolysaccharide (LPS) challenge. At 24 hours post-treatment, bronchoalveolar lavage fluid (BALF) and lung tissues were collected for analysis. The ratio, number, phenotype, and function of immune cells and cytokine levels were measured. Additionally, murine bone marrow-derived macrophages (BMDMs) were prepared and stimulated with LPS and TSLP to further verify our findings experimentally. To explore the molecular mechanisms of TSLP's effect, analysis of transcriptome sequencing and single-cell transcriptome sequencing and subsequent experiments were performed. In LPS-induced acute lung injury models, pretreatment with TSLP significantly alleviated lung injury, suppressed inflammatory cytokines secretion, and reduced macrophages and neutrophils infiltration. In addition, TSLP treatment significantly inhibited M1 macrophage polarization and promoted M2 macrophage differentiation. Transcriptome sequencing suggested IFN-γ as a potential target of TSLP, and single-cell transcriptome sequencing showed that innate like T cells are important source of IFN-γ. Consistently, flow cytometry showed that proportion of IFN-γ-producing iNKT cells was decreased by TSLP administration in the acute lung injury model. Intriguingly, Jα18-/- mice, which are completely deficient in invariant natural killer T (iNKT) cells, exhibited not only significantly less severe lung inflammation but also a notably higher degree of anti-inflammatory Arg1+ M2 macrophages infiltration when compared with their LPS-sensitized wild-type counterparts. These findings not only underscore the crucial role of TSLP in the regulation of sepsis-associated ARDS but also demonstrate its potential clinical value as both a predictive biomarker for early detection and a molecular target for therapeutic intervention.

Introduction: N-Acetylcysteine (NAC) has long served been clinically as a mucolytic agent for chronic bronchitis. It is also a cytoprotective agent through inhibition of the production of pro-inflammatory cytokines and free radicals. Therefore, its role of minimizing inflammatory lung condition, such as acute lung injury (ALI) need to be investigated. Experimental lung injury caused by phorbol myristate acetate (PMA) is characterized by pulmonary edema and inflammatory cells infiltration. PMA activated neutrophils in vivo and in vitro to release free radicals, pro-inflammatory cytokines, nitric oxide (NO) and other mediators. This study aimed to evaluate the effects of N-Acetylcysteine (NAC) on the PMA-induced ALI and associated changes in rat lung model.Methods: The isolated rat's lung was utilized to investigate the effects of pretreatment of NAC on the ALI and associated changes following administration of PMA. The degree of lung injury was assessed by various parameters including protein concentration, lactate dehydrogenase (LDH) activity, exhaled nitric oxide (NO), total cells and polymorphonuclear leukocyte (PMN) cell counts in the bronchoalveolar lavage fluid (BALF), the pulmonary arterial pressure (PAP) and microvascular permeability (K(subscript fc)), and the concentration of nitrate/nitrite, methyl guanidine (MG), tumor necrosis factor(subscript α) (TNF(subscript α)) and interleukin-1(subscript β) (IL-1(subscript β)) in lung perfusate. In addition, we also evaluate the lung injury by histopathological examination and by grading system for the lung injury score (LIS).Result: PMA caused severe ALI as evidenced by the marked increases in exhaled NO, BALF, histopathological changes, and LIS. It also increased the nitrate/nitrite, MG, TNF(subscript α), and IL-1(subscript β) in lung perfusate (P＜0.05 compared with vehicle group). Pretreatment with NAC significantly attenuated these changes and abrogated the extent of ALI (P＜0.05 compared with the PMA group). Conclusions: Our results suggest that NAC exerts strong protective effects on the PMA-induced ALI and associated alterations. The mechanisms are possibly attributable to it's antioxidant actions, inhibition of pro-inflammatory cytokines, and restoration of glutathione enzymes.

Hemorrhagic shock (HS) is defined as a reduction in tissue oxygenation and organ dysfunction due to severe blood loss. Lung injury is a frequent complication of HS. Baicalin, isolated from Radix Scutellariae, has been reported to profile the antitumor, anti-oxidative, anti-inflammatory, and antibacterial roles in various pathological processes. Nevertheless, the effects of baicalin on HS-induced lung injury are unclear. This study aims to examine the therapeutic effects of baicalin on lung injury. We first established the lung injury rat models by withdrawing blood in the femoral artery followed by resuscitation. A pathological analysis showed that HS-administrated rats presented severe capillary leakage and pulmonary edema, while baicalin therapy alleviated the symptoms. Baicalin therapy reduced the number of macrophages and neutrophils in bronchoalveolar lavage fluid and decreased the expression and activity of myeloperoxidase (neutrophile infiltration marker) in the lung tissues of HS rats, indicating that baicalin alleviated HS-induced infiltration of inflammatory cells. The secretion of inflammatory cytokines, including interleukin (IL)-1[Formula: see text], IL-6, IL-18, and tumor necrosis factor [Formula: see text] (TNF-[Formula: see text]), as well as the activation of the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing-3 (NLRP3) inflammasome, were inhibited by baicalin administration. Furthermore, we found that the NF-[Formula: see text]B pathway, a canonical pro-inflammatory pathway, was also blocked after treatment with baicalin in HS-evoked rats, as indicated by the decreased expression of p65 and p65 phosphorylation in the lung tissues. In summary, we infer that baicalin may exert a protective role in HS-induced lung injury by suppressing the activation of NLRP3 inflammasome via the NF-[Formula: see text]B pathway.

Effects of COX-2 inhibitor on ventilator-induced lung injury in rats