Lung Inflammation In Mice Research Articles

RGS10 Reduces Lethal Influenza Infection and Associated Lung Inflammation in Mice.

Seasonal influenza epidemics represent a significant global health threat. The exacerbated immune response triggered by respiratory influenza virus infection causes severe pulmonary damage and contributes to substantial morbidity and mortality. Regulator of G-protein signaling 10 (RGS10) belongs to the RGS protein family that act as GTPase activating proteins for heterotrimeric G proteins to terminate signaling pathways downstream of G protein-coupled receptors. While RGS10 is highly expressed in immune cells, in particular monocytes and macrophages, where it has strong anti-inflammatory effects, its physiological role in the respiratory immune system has not been explored yet. Here, we show that Rgs10 negatively modulates lung immune and inflammatory responses associated with severe influenza H1N1 virus respiratory infection in a mouse model. In response to influenza A virus challenge, mice lacking RGS10 experience enhanced weight loss and lung viral titers, higher mortality and significantly faster disease onset. Deficiency of Rgs10 upregulates the levels of several proinflammatory cytokines and chemokines and increases myeloid leukocyte accumulation in the infected lung, markedly neutrophils, monocytes, and inflammatory monocytes, which is associated with more pronounced lung damage. Consistent with this, influenza-infected Rgs10-deficent lungs contain more neutrophil extracellular traps and exhibit higher neutrophil elastase activities than wild-type lungs. Overall, these findings propose a novel, in vivo role for RGS10 in the respiratory immune system controlling myeloid leukocyte infiltration, viral clearance and associated clinical symptoms following lethal influenza challenge. RGS10 also holds promise as a new, potential therapeutic target for respiratory infections.

Role of necroptosis of alveolar macrophages in acute lung inflammation of mice exposed to titanium dioxide nanoparticles

Titanium dioxide (TiO2) nanoparticles are indispensable for daily life but induce acute inflammation, mainly via inhalation exposure. TiO2 nanoparticles can be phagocytosed by alveolar macrophages (AMs) in vivo and cause necroptosis of exposed cells in vitro. However, the relationship between localization of TiO2 nanoparticles in the lungs after exposure and their biological responses including cell death and inflammation remains unclear. This study was conducted to investigate the intra/extracellular localization of TiO2 nanoparticles in murine lungs at 24 h after intratracheal exposure to rutile TiO2 nanoparticles and subsequent local biological reactions, specifically necroptosis of AMs and lung inflammation. We found that TiO2 exposure induced leukocyte migration into the alveolar region and increased the secretion of C-C motif ligand (CCL) 3 in the bronchoalveolar lavage (BAL) fluid. A combination of Raman spectroscopy and staining of cell and tissue samples confirmed that AMs phagocytose TiO2. AMs that phagocytosed TiO2 nanoparticles showed necroptosis, characterized by the expression of phosphorylated mixed lineage kinase domain-like protein and translocation of high mobility group box-1 from the cell nucleus to the cytoplasm. In primary cultured AMs, TiO2 also induced necroptosis and increased the secretion of CCL3. Necroptosis inhibitors suppressed the increase in CCL3 secretion in both the BAL fluid and culture supernatant of AMs and suppressed the increase in leukocytes in the BAL fluid. These data suggest that necroptosis of AMs that phagocytose TiO2 nanoparticles is involved as part of the mechanism by which TiO2 induces acute lung inflammation.

Type-4 Phosphodiesterase (PDE4) Blockade Reduces NETosis in Cystic Fibrosis.

Neutrophilic inflammation is a key determinant of cystic fibrosis (CF) lung disease. Neutrophil-derived free DNA, released in the form of extracellular traps (NETs), significantly correlates with impaired lung function in patients with CF, underlying their pathogenetic role in CF lung disease. Thus, specific approaches to control NETosis of neutrophils migrated into the lungs may be clinically relevant in CF. We investigated the efficacy of phosphodiesterase (PDE) type-4 inhibitors, in vitro, on NET release by neutrophils from healthy volunteers and individuals with CF, and in vivo, on NET accumulation and lung inflammation in mice infected with Pseudomonas aeruginosa. PDE4 blockade curbed endotoxin-induced NET production and preserved cellular integrity and apoptosis in neutrophils, from healthy subjects and patients with CF, challenged with endotoxin, in vitro. The pharmacological effects of PDE4 inhibitors were significantly more evident on CF neutrophils. In a mouse model of Pseudomonas aeruginosa chronic infection, aerosol treatment with roflumilast, a selective PDE4 inhibitor, gave a significant reduction in free DNA in the BALF. This was accompanied by reduced citrullination of histone H3 in neutrophils migrated into the airways. Roflumilast-treated mice showed a significant improvement in weight recovery. Our study provides the first evidence that PDE4 blockade controls NETosis in vitro and in vivo, in CF-relevant models. Since selective PDE4 inhibitors have been recently approved for the treatment of COPD and psoriasis, our present results encourage clinical trials to test the efficacy of this class of drugs in CF.

Selenium-Containing Compound Ameliorates Lipopolysaccharide-Induced Acute Lung Injury via Regulating the MAPK/AP-1 Pathway.

Abstract-Acute lung injury (ALI) is characterized by a series of inflammatory reactions and serves as the main cause of mortality in intensive care unit patients. Although great progress has been made in understanding the pathophysiology of ALI, there are no effective treatments in clinic. Recently, we have synthesized a selenium-containing compound, which possesses obvious anti-inflammatory activity. The aim of the present study is to evaluate the protective effects of the selenium-containing compound 34# in LPS-induced ALI in mice as well as its underlying mechanism. Compound 34# was found to inhibit LPS-induced macrophage inflammatory cytokine release. These effects were observed to be produced via suppression of the MAPK/AP-1 pathway. Compound 34# was also noted to attenuate the LPS-induced lung inflammation in mice with ALI. The corresponding results suggested that compound 34# possesses remarkable protective effects on LPS-induced ALI. Furthermore, the MAPK/AP-1 pathway may prove to be the underlying mechanism. Accordingly, compound 34# may serve as a potential candidate for the prevention of ALI.

Machine learning identifies molecular regulators and therapeutics for targeting SARS‐CoV2‐induced cytokine release

Although 15–20% of COVID‐19 patients experience hyper‐inflammation induced by massive cytokine production, cellular triggers of this process and strategies to target them remain poorly understood. Here, we show that the N‐terminal domain (NTD) of the SARS‐CoV‐2 spike protein substantially induces multiple inflammatory molecules in myeloid cells and human PBMCs. Using a combination of phenotypic screening with machine learning‐based modeling, we identified and experimentally validated several protein kinases, including JAK1, EPHA7, IRAK1, MAPK12, and MAP3K8, as essential downstream mediators of NTD‐induced cytokine production, implicating the role of multiple signaling pathways in cytokine release. Further, we found several FDA‐approved drugs, including ponatinib, and cobimetinib as potent inhibitors of the NTD‐mediated cytokine release. Treatment with ponatinib outperforms other drugs, including dexamethasone and baricitinib, inhibiting all cytokines in response to the NTD from SARS‐CoV‐2 and emerging variants. Finally, ponatinib treatment inhibits lipopolysaccharide‐mediated cytokine release in myeloid cells in vitro and lung inflammation mouse model. Together, we propose that agents targeting multiple kinases required for SARS‐CoV‐2‐mediated cytokine release, such as ponatinib, may represent an attractive therapeutic option for treating moderate to severe COVID‐19.

Oral administration of Clostridium butyricum rescues streptomycin-exacerbated respiratory syncytial virus-induced lung inflammation in mice

ABSTRACT Changes in the intestinal microbiota indirectly impact the health of mucosa distal to the intestine, particularly the respiratory tract. However, the effects of intestinal microbiota dysbiosis on the regulation of respiratory syncytial virus (RSV) infection are not clear. In this study, we examined the effects of altering the intestinal microbiota on the pulmonary immune response against RSV infection. BALB/c mice were treated with streptomycin before infection with RSV to study the altered immune response. The ingestion of streptomycin led to a marked alteration in the intestinal microbiota with a reduced abundance of Lactobacillus and Clostridium genera, followed by greatly aggravated pulmonary inflammation in response to RSV infection. This aggravated inflammation was associated with a dysregulated immune response against RSV infection, characterized by the increased expression of IFN-γ and IL-17 and increased pulmonary M1-like macrophage polarization, and decreased expression of IL-5. Supplementation of Clostridium butyricum (CB) prevented aggravated inflammation and the dysregulated immune response characterized by greater M2 polarization of pulmonary macrophages and decreased release of IFN-γ and IL-17 as well as increased IL-5 levels. Furthermore, in vitro and in vivo experiments identified that butyrate, the main metabolite produced by CB, promoted M2 polarization of macrophages in RSV-infected mice exposed to streptomycin. Together, these results demonstrate the mechanism by which intestinal microbiota modulate the pulmonary immune response to RSV infection.

Integrated evaluation of lung disease in single animals.

During infectious disease, pathogen load drives inflammation and immune response that together contribute to tissue injury often resulting in organ dysfunction. Pulmonary failure in SARS-CoV2-infected hospitalized COVID-19 patients is one such prominent example. Intervention strategies require characterization of the host-pathogen interaction by accurately assessing all of the above-mentioned disease parameters. To study infection in intact mammals, mice are often used as essential genetic models. Due to humane concerns, there is a constant unmet demand to develop studies that reduce the number of mice utilized while generating objective data. Here, we describe an integrated method of evaluating lung inflammation in mice infected with Pseudomonas aeruginosa or murine gammaherpesvirus (MHV)-68. This method conserves animal resources while permitting evaluation of disease mechanisms in both infection settings. Lungs from a single euthanized mouse were used for two purposes-biological assays to determine inflammation and infection load, as well as histology to evaluate tissue architecture. For this concurrent assessment of multiple parameters from a single euthanized mouse, we limit in-situ formalin fixation to the right lung of the cadaver. The unfixed left lung is collected immediately and divided into several segments for biological assays including determination of pathogen titer, assessment of infection-driven cytokine levels and appearance of cell death markers. In situ fixed right lung was then processed for histological determination of tissue injury and confirmation of infection-driven cell death patterns. This method reduces overall animal use and minimizes inter-animal variability that results from sacrificing different animals for different types of assays. The technique can be applied to any lung disease study in mice or other mammals.

Substance P-induced lung inflammation in mice is mast cell dependent.

Allergic asthma is a common inflammatory lung disease and a major health problem worldwide. Mast cells (MCs) play a key role in the early-stage pathophysiology of allergic asthma. Substance P (SP) functions in neurogenic inflammation by activating MCs, and therefore, it may to participate in the occurrence and development of asthma. We examined the relationship between SP and lung inflammation, and also whether SP can directly trigger asthma. We measured the number of peripheral blood eosinophils, neutrophils and basophils and evaluated the levels of IgE and SP in blood samples of 86 individuals with allergic asthma. Serum IgE and SP levels were also determined in 29 healthy individuals. C57BL/6 mice were subjected to different doses of SP, and bronchoalveolar lavage fluid (BALF) was collected to count the inflammatory cells. Lung tissues were analysed using histopathological methods to evaluate lung peribronchial inflammation, fibrosis and glycogen deposition. Levels of IgE, interleukin (IL)-1, IL-2, IL-4, IL-5, IL-13, IL-17 and IFN-γ were determined in mouse serum. Substance P levels were increased in the serum samples of patients with asthma. SP induced mouse lung peribronchial inflammation, fibrosis and glycogen deposition, with high levels of Th2-related cytokines such as IL-4, IL-5 and IL-13 observed in the BALF. Furthermore, low level of total IgE was noted in the serum, and SP had little effect on MC-deficient kitW-sh/W-sh mice. Substance P levels increased significantly in serum of asthmatic patients and independently associated with the risk of asthma. Furthermore, SP induced Th2 lung inflammation in mice, which was dependent on MCs.

Elucidation of the Molecular Pathways Involved in the Protective Effects of AUY-922 in LPS-Induced Inflammation in Mouse Lungs.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) cause thousands of deaths every year and are associated with high mortality rates (~40%) due to the lack of efficient therapies. Understanding the molecular mechanisms associated with those diseases will most probably lead to novel therapeutics. In the present study, we investigated the effects of the Hsp90 inhibitor AUY-922 in the major inflammatory pathways of mouse lungs. Mice were treated with LPS (1.6 mg/kg) via intratracheal instillation for 24 h and were then post-treated intraperitoneally with AUY-922 (10 mg/kg). The animals were examined 48 h after AUY-922 injection. LPS activated the TLR4-mediated signaling pathways, which in turn induced the release of different inflammatory cytokines and chemokines. AUY-922 suppressed the LPS-induced inflammation by inhibiting major pro-inflammatory pathways (e.g., JAK2/STAT3, MAPKs), and downregulated the IL-1β, IL-6, MCP-1 and TNFα. The expression levels of the redox regulator APE1/Ref1, as well as the DNA-damage inducible kinases ATM and ATR, were also increased after LPS treatment. Those effects were counteracted by AUY-922. Interestingly, this Hsp90 inhibitor abolished the LPS-induced pIRE1α suppression, a major component of the unfolded protein response. Our study elucidates the molecular pathways involved in the progression of murine inflammation and supports our efforts on the development of new therapeutics against lung inflammatory diseases and sepsis.

High DHA tuna oil alleviated cigarette smoking exposure induced lung inflammation via the regulation of gut microbiota and serum metabolites

Abstract In this study, the dose-dependent beneficial effects of tuna oil (TO) on cigarette smoke exposure induced lung inflammation were investigated. Treatments with low- (LD), moderate- (MD) and high-dosage (HD) of TO reduce the C-reactive protein concentration in serum, significantly down-regulated and up-regulated the mRNA levels of proinflammatory and anti-inflammatory cytokines in the lung, respectively. TO treatment inhibited the activation of the nuclear factor-kappaB (NF-κB) signaling pathway and the NLR family pyrin domain-containing 3 (NLRP3) inflammasome. In addition, TO treatments reduced the MDA concentration and enhanced the activities of SOD and GSH-Px in serum. What’s more, TO treatment modulated the gut microbiota by increasing the abundance of Lactobacillus species and short-chain fatty acid producers and decreasing the abundance of opportunistic pathogens, as well as affecting the amino acid metabolism in serum. This research clarified the anti-inflammatory mechanism of TO on cigarette smoking exposure induced lung inflammation in mice.

Interferon-beta (IFNb) Reprograms Pathogenic Lung Dendritic Cells in Human Chronic Lung Allograft Dysfunction (CLAD)

<h3>Purpose</h3> Dendritic cells (DC) are central to the induction and maintenance of T regulatory cells (T-regs) and lung allograft tolerance. We previously identified tumor necrosis factor 2 positive DC (TNFR2⁺DC) as a subset of lung resident DC responsible for antigen-specific Th2 mediated response and inflammation in mice model of asthma. Interestingly, TNFR2⁺DC is plastic and intranasal administration of IFNβ reprograms TNFR2⁺DC to generate regulatory T-cells and reverses lung inflammation in mice. We set out to characterize TNFR2⁺DC and the response to IFNβ in healthy human donor and CLAD lungs. <h3>Methods</h3> We evaluated single-cell suspensions from the unused healthy human donor lungs from the lobar transplantation, and CLAD explant lung tissue from patients undergoing re-transplantation. Identification of TNFR2⁺DC populations and the response to IFNβ (200ng IFNβ, R&D systems INC. MN, USA) were investigated with flow cytometry analysis. <h3>Results</h3> We successfully identified the TNFR2⁺DC population in healthy donor and CLAD lung tissues (n=4/group) (Figure 1A). The healthy lung TNFR2⁺DC constitutively express TGFβ1, IDO-1, and Arg-1, which has a similar phenotype to tolerogenic DC in mouse lungs. Conversely, TNFR2⁺DC from CLAD patients had decreased TGFβ1, Arg-1, PD-L1, but increased IL-4 and IL-23 expression (Figure 1B). Treatment with IFNβ increased TGFβ1, Arg1, and decreased IL-4 expression in CLAD TNFR2⁺DC. Thus, similar to mice, treatment with IFNβ reprograms pathogenic TNFR2⁺DC in CLAD to phenotypically tolerogenic DC (Figure 1C). <h3>Conclusion</h3> We identified TNFR2⁺DC in healthy human donor lung and CLAD. Healthy human donor lung has a phenotypically tolerogenic TNFR2⁺DC. Conversely, TNFR2⁺DC in CLAD shows inflammatory markers, and treatment with IFNβ reprograms pathogenic DC to a tolerogenic phenotype. Further studies are required to assess the utility of TNFR2⁺DC plasticity for achieving lung allograft tolerance.

25-Hydroxycholesterol metabolism is altered by lung inflammation, and its local administration modulates lung inflammation in mice.

Inflammation is a critical component of many lung diseases including asthma and acute lung injury (ALI). Using high-performance liquid chromatography-mass spectrometry, we quantified the levels of oxysterols in two different murine models of lung diseases. These are lipid mediators derived from cholesterol and known to modulate immunity and inflammation. Interestingly, 25-hydroxycholesterol (25-OHC) was the only oxysterol with altered levels during lung inflammation, and its levels were differently affected according to the model. Therefore, we sought to assess how this oxysterol would affect lung inflammatory responses. In a model of lipopolysaccharide (LPS)-induced acute lung inflammation, 25-OHC levels were increased, and most of the hallmarks of the model (eg, leukocyte recruitment, mRNA expression, and secretion of inflammatory cytokines) were decreased following its intratracheal administration. We also found that, when administered in the lung, 25-OHC is metabolized locally into 25-hydroxycholesterol-3-sulfate and 7α,25-dihydroxycholesterol. Their administration in the lungs did not recapitulate all the effects of 25-OHC. Conversely, in a model of allergic asthma induced by intranasal administration of house dust mites (HDM), 25-OHC levels were decreased, and when intranasally administered, this oxysterol worsened the hallmarks of the model (eg, leukocyte recruitment, tissue remodeling [epithelium thickening and peribranchial fibrosis], and cytokine expression) and induced changes in leukotriene levels. Ex vivo, we found that 25-OHC decreases LPS-induced primary alveolar macrophage activation while having no effect on neutrophil activation. Its sulfated metabolite, 25-hydroxycholesterol-3-sulfate, decreased neutrophil, but not macrophage activation. Taken together, our data support a differential role of 25-OHC in ALI and allergic inflammation models.

VIWITHAN: A STANDARDIZED ASHWAGANDHA EXTRACT AMELIORATES OVALBUMININDUCED AIRWAY-INFLAMMATION AND OXIDATIVE STRESS IN MOUSE MODEL

Objective: Withania somnifera, commonly known as Ashwagandha, Indian ginseng, has been used in Ayurvedic and indigenous medicinal preparations for various disease conditions since long time. In the present study, we investigated the protective effects of Viwithan, a standardized proprietary extract from Ashwagandha roots, against airway-inflammation and oxidative stress modulation in an ovalbumin (OVA)-induced murine model of inflammation.&#x0D; Methods: Allergic asthma was initiated in BALB/c mice by sensitizing with OVA on days 1 and 14, followed by intranasal challenge with OVA on days 27, 28, and 29. Mice were administered Viwithan (200 and 400 mg/kg) by oral gavage before challenge. Then, mice were evaluated for the presence of airway inflammation, production of allergen-specific cytokine response, lung pathology, and oxidative stress modulation.&#x0D; Results: The results showed that treatment with Viwithan attenuated OVA-induced lung inflammation in mice. Viwithan significantly attenuated inflammatory cell infiltration into the bronchoalveolar lavage fluid and markedly reduced the levels of pro-inflammatory cytokines, interleukin-10, and transforming growth factor-β1 in lung tissues. Viwithan treatment considerably reduced the lung weight in OVA-sensitized mice. Viwithan markedly attenuated the OVA-induced generation of reactive oxygen species in lung tissues.&#x0D; Conclusion: Together, these results suggested that Viwithan alleviates OVA-induced airway-inflammation and oxidative stress, highlighting the potential of standardized Ashwagandha extract as a useful therapeutic agent for pulmonary fibrosis management.

IL36 is a critical upstream amplifier of neutrophilic lung inflammation in mice

IL-36, which belongs to the IL-1 superfamily, is increasingly linked to neutrophilic inflammation. Here, we combined in vivo and in vitro approaches using primary mouse and human cells, as well as, acute and chronic mouse models of lung inflammation to provide mechanistic insight into the intercellular signaling pathways and mechanisms through which IL-36 promotes lung inflammation. IL-36 receptor deficient mice exposed to cigarette smoke or cigarette smoke and H1N1 influenza virus had attenuated lung inflammation compared with wild-type controls. We identified neutrophils as a source of IL-36 and show that IL-36 is a key upstream amplifier of lung inflammation by promoting activation of neutrophils, macrophages and fibroblasts through cooperation with GM-CSF and the viral mimic poly(I:C). Our data implicate IL-36, independent of other IL-1 family members, as a key upstream amplifier of neutrophilic lung inflammation, providing a rationale for targeting IL-36 to improve treatment of a variety of neutrophilic lung diseases.

Gender Differences in Low-Molecular-Mass-Induced Acute Lung Inflammation in Mice.

Gender differences in pulmonary inflammation have been well documented. Although low molecular mass hyaluronan (LMMHA) is known to trigger pulmonary lung inflammation, sex differences in susceptibility to LMMHA are still unknown. In this study, we test the hypothesis that mice may display sex-specific differences after LMMHA administration. After LMMHA administration, male mice have higher neutrophil, cytokine, and chemokine counts compared to that of their female counterparts. Additionally, Ovariectomized (OVX) mice show greater LMMHA-induced inflammation compared to that of mice with intact ovaries. Injections of OVX mice with 17β-estradiol can decrease inflammatory responses in the OVX mice. These results show that ovarian hormones regulate LMMHA induced lung inflammation.

Exposure to Polyhexamethylene Guanidine Exacerbates Bronchial Hyperresponsiveness and Lung Inflammation in a Mouse Model of Ovalbumin-Induced Asthma.

Humidifier disinfectants (HDs) exposure has now been associated with acute lung injury and pulmonary fibrosis; polyhexamethylene guanidine (PHMG) has been confirmed to cause severe lung inflammation and fibrosis in mice. Recent evidence also indicates that HDs exposure increases the asthma risk in children, but the underlying mechanisms remain unclear. We aimed to investigate the effects of PHMG exposure on asthma in mice and the potential underlying mechanisms. BALB/c mice were intranasally administered PHMG (0.1 mg/kg/day; 5 days per week) during 2 episodes of ovalbumin (OVA) sensitization and were then challenged with 1% OVA by inhalation. Bronchial hyperresponsiveness (BHR), inflammatory cell influx into bronchoalveolar lavage (BAL) fluid, serum total and OVA-specific immunoglobulin (Ig) E levels, and histopathological changes in the lung were analyzed. The levels of asthma-related cytokines and chemokines were assayed in the lung tissues to evaluate possible mechanisms. Exposure to PHMG following OVA sensitization and challenge significantly enhanced BHR, inflammatory cell counts in BAL fluid, airway inflammation, and total serum IgE levels in the asthma mouse model. In addition, the levels of chemokine ligand (CCL) 11 and serpine F1/pigment epithelium-derived factor (SERPINF1) were significantly elevated in the lungs of these mice compared to those in the control and OVA-treated only groups. Our findings suggest that PHMG can enhance the development of allergic responses and lung inflammation via CCL11- and SERPINF1-induced signaling in a mouse model of asthma.

Analysis of T-Cells in Inflamed Nonlymphoid Tissues.

Under chronic inflammatory conditions, T and B cells are frequently found in nonlymphoid tissues. We recently identified a follicular helper-like T cell population in inflamed lung tissue, which drives the local differentiation of antigen-specific B cells into germinal center-like cells and plasma blasts. Here, we describe a lung inflammation mouse model, which is ideally suited to analyze antigen-specific T and B cells in secondary lymphoid organs and inflamed nonlymphoid tissue in parallel.

Imperatorin ameliorates mast cell-mediated allergic airway inflammation by inhibiting MRGPRX2 and CamKII/ERK signaling pathway

BackgroundAllergic asthma is a common inflammatory lung disease associated with complex pathogenesis. Mast cell (MC) is one of the key drivers of allergic asthma, Mas-related G protein-coupled receptor X2 (MRGPRX2) on the MC could mediate MC activation and trigger a pseudo-allergic reaction. Imperatorin (IMP), the main active compound of Radix Angelicae Dahuricae, has been reported to exert various pharmacological effects. In this study, we focused on the therapeutical mechanism of IMP on MRGPRX2-induced pseudo-allergy and allergic asthma. MethodsWe examined the effect of IMP on MRGPRX2 related mast cell activation in mouse peritoneal MC (MPMC), Human Laboratory of Allergic Disease 2 MCs (LAD2 cells) and Mrgprx2-expressing HEK293 cells. Molecular docking and Surface plasmon resonance (SPR) were taken to reveal the binding character between IMP and MRPGRX2. MRGPRX2 downstream proteins were also detected by western blotting. IgE-independent responses was evaluated by using passive cutaneous anaphylaxis (PCA) and active systemic anaphylaxis (ASA) models. The therapeutic effect of IMP on asthma was evaluated by a lung inflammation mouse model which was induced by ovalbumin (OVA). ResultsIMP was found to reduce substance P (SP) induced calcium flux and suppressed degranulation of MC. SP can promote the phosphorylation of ERK and CamKII, which regulates the synthesis of inflammatory factors such as MIP-2 and TNF-α in MC. In vivo assays revealed that IMP can mitigate SP-induced mouse PCA and ASA. IMP could also mitigate lung inflammation in an OVA induced mice model by inhibiting MC activation in the lung tissue. Furthermore, IMP binds well to MRGPRX2 protein. The binding constant (KD) is 4.48 ± 0.49 × 10−7 M. The data suggeste that IMP is a novel inhibitor of MRGPRX2 to treat allergic asthma.

The Effects of Particulate Matter on C57BL/6 Peritoneal and Alveolar Macrophages

The presence of ambient particulate matter (PM) poses more dangers to human health than that of other common air pollutants such as Carbon dioxide (Co2) and ozone. Epidemiologic studies show a direct correlation between PM and the risk of respiratory and cardiovascular diseases. The immune system seems to play a critical role in the process of these diseases. The main goal of this study was to investigate the effect of Tehran particulate matter in two aerodynamic diameters (PM2.5 and PM10) on alveolar macrophages (AM) from C57/BL6 mice. To evaluate the inflammatory effects of PMs, cultured alveolar, and peritoneal macrophages were treated with PM2.5 and PM10 (concentrations of 5 µg/mL and 10 µg/mL). Tumor necrosis factor-alpha (TNF-α) and IL-10 (representatives of inflammatory and anti-inflammatory cytokines, respectively) were assessed in the culture supernatant by ELISA. Expression of arginase and inducible nitric oxide synthase (iNOS) genes was carried out by quantitative real-time PCR. Different functional types of cultured alveolar macrophages (M1, M2) were also determined in this study. Our results suggest that PM2.5 induces M1 inflammatory phenotype in comparison with PM10. We found Also, an increase in TNF-α and M1-related gene expression (iNOS), as well as a decrease in both IL-10 and M2 phenotype genes (Arginase). Moreover, a reduction in phagocytic capacity and increased apoptosis function of macrophage cells were detected.PM2.5 as a major component in hydrocarbons has a considerable effect on polarizing the alveolar macrophages to an inflammatory phenotype and eliciting lung inflammation in mice.

MCC950, a NLRP3 inhibitor, ameliorates lipopolysaccharide-induced lung inflammation in mice

Acute respiratory distress syndrome/chronic obstructive pulmonary disease (ARDS/COPD) is a diffuse inflammatory injury of the lung that is characterized by respiratory distress and vascular leakage and is caused by various factors. Although the treatment strategy for ARDS/COPD continues to be improved, it still lacks effective drugs. MCC950 is a potent and selective inhibitor ofthe nucleotide-binding oligomerization domain-like-receptor family pyrin domain-containing 3 (NLRP3) inflammasome. However, there have been no reports on the effects of MCC950 on lipopolysaccharide (LPS)-induced lung inflammation in mice. The objective of the present study was to evaluate the effects of MCC950 (given either intranasally or intraperitoneally) on inhibiting LPS-induced lung inflammation in mice. Acute lung inflammation was induced by intratracheal administration of LPS in ICR mice. The results showed that MCC950 at 50 mg/kg efficiently suppressed neutrophil lymphocytes (p < 0.001) and macrophage accumulation (p < 0.01) in bronchoalveolar lavage fluid (BALF) in LPS-instilled mice. In addition, hematoxylin and eosin (H&E) staining revealed that MCC950 at 50 mg/kg significantly inhibited pathological progress in the lung tissues (p < 0.01). Furthermore, treatment with MCC950 substantially reduced mRNA expression of IL-1β, IL-8, TGF-β1, and MMP-9 and also reduced protein levels of IL-1β, IL-18 and caspase-1 at 24 h after LPS instillation. The results of the present study indicate that MCC950 effectively inhibits LPS-induced lung inflammation in vivo, which can be considered for clinical translation.