Alveolar Macrophage Production Research Articles

The formation of lamellar body-like structures may be a trigger of cetylpyridinium chloride-induced cell death and inflammatory response

Cetylpyridinium chloride (CPC) is a quaternary ammonium compound used widely in health and personal care products. Meanwhile, due to its increasing use, its potential adverse health effects are emerging as a topic of public concern. In this study, we first administered CPC by pharyngeal aspiration to determine the survival level (the maximum concentration at which no death is observed) and then administered CPC to mice repeatedly for 28 days using the survival level as the highest concentration. CPC increased the total number of pulmonary cells secreting pro- and anti-inflammatory cytokines and chemokines. Infiltration of inflammatory cells, production of foamy alveolar macrophages, and chronic inflammatory lesions were found in the lung tissue of male and female mice exposed to the highest dose of CPC. We also investigated the toxicity mechanism using BEAS-2B cells isolated from normal human bronchial epithelium. At 6 h after exposure to CPC, the cells underwent non-apoptotic cell death, especially at concentrations greater than 2 μg/mL. The expression of the transferrin receptor was remarkably enhanced, and the expression of proteins that contribute to intracellular iron storage was inhibited. The expression of both mitochondrial SOD and catalase increased with CPC concentration, and PARP protein was cleaved, suggesting possible DNA damage. In addition, the internal structure of mitochondria was disrupted, and fusion between damaged organelles was observed in the cytoplasm. Most importantly, lamellar body-like structures and autophagosome-like vacuoles were found in CPC-treated cells, with enhanced expression of ABCA3 protein, a marker for lamellar body, and a docking score between ABCA3 protein and CPC was considered to be approximately −6.8969 kcal/mol. From these results, we propose that mitochondrial damage and iron depletion may contribute to CPC-induced non-apoptotic cell death and that pulmonary accumulation of cell debris may be closely associated with the inflammatory response. Furthermore, we hypothesize that the formation of lamellar body-like structures may be a trigger for CPC-induced cell death.

ASFV pA151R negatively regulates type I IFN production via degrading E3 ligase TRAF6.

African swine fever (ASF) caused by African swine fever virus (ASFV) is a highly mortal and hemorrhagic infectious disease in pigs. Previous studies have indicated that ASFV modulates interferon (IFN) production. In this study, we demonstrated that ASFV pA151R negatively regulated type I IFN production. Ectopic expression of pA151R dramatically inhibited K63-linked polyubiquitination and Ser172 phosphorylation of TANK-binding kinase 1 (TBK1). Mechanically, we demonstrated that E3 ligase TNF receptor-associated factor 6 (TRAF6) participated in the ubiquitination of TBK1 in cGAS-STING signaling pathway. We showed that pA151R interacted with TRAF6 and degraded it through apoptosis pathway, leading to the disruption of TBK1 and TRAF6 interaction. Moreover, we clarified that the amino acids H102, C109, C132, and C135 in pA151R were crucial for pA151R to inhibit type I interferon production. In addition, we verified that overexpression of pA151R facilitated DNA virus Herpes simplex virus 1 (HSV-1) replication by inhibiting IFN-β production. Importantly, knockdown of pA151R inhibited ASFV replication and enhanced IFN-β production in porcine alveolar macrophages (PAMs). Our findings will help understand how ASFV escapes host antiviral immune responses and develop effective ASFV vaccines.

The African swine fever virus I10L protein inhibits the NF-κB signaling pathway by targeting IKKβ.

Proinflammatory factors play important roles in the pathogenesis of African swine fever virus (ASFV), which is the causative agent of African swine fever (ASF), a highly contagious and severe hemorrhagic disease. Efforts in the prevention and treatment of ASF have been severely hindered by knowledge gaps in viral proteins responsible for modulating host antiviral responses. In this study, we identified the I10L protein (pI10L) of ASFV as a potential inhibitor of the TNF-α- and IL-1β-triggered NF-κB signaling pathway, the most canonical and important part of host inflammatory responses. The ectopically expressed pI10L remarkably suppressed the activation of NF-κB signaling in HEK293T and PK-15 cells. The ASFV mutant lacking the I10L gene (ASFVΔI10L) induced higher levels of proinflammatory cytokines production in primary porcine alveolar macrophages (PAMs) compared with its parental ASFV HLJ/2018 strain (ASFVWT). Mechanistic studies suggest that pI10L inhibits IKKβ phosphorylation by reducing the K63-linked ubiquitination of NEMO, which is necessary for the activation of IKKβ. Morever, pI10L interacts with the kinase domain of IKKβ through its N-terminus, and consequently blocks the association of IKKβ with its substrates IκBα and p65, leading to reduced phosphorylation. In addition, the nuclear translocation efficiency of p65 was also altered by pI10L. Further biochemical evidence supported that the amino acids 1-102 on pI10L were essential for the pI10L-mediated suppression of the NF-κB signaling pathway. The present study clarifies the immunosuppressive activity of pI10L, and provides novel insights into the understanding of ASFV pathobiology and the development of vaccines against ASF. IMPORTANCE African swine fever (ASF), caused by the African swine fever virus (ASFV), is now widespread in many countries and severely affects the commercial rearing of swine. To date, few safe and effective vaccines or antiviral strategies have been marketed due to large gaps in knowledge regarding ASFV pathobiology and immune evasion mechanisms. In this study, we deciphered the important role of the ASFV-encoded I10L protein in the TNF-α-/IL-1β-triggered NF-κB signaling pathway. This study provides novel insights into the pathogenesis of ASFV and thus contributes to the development of vaccines against ASF.

P2X7 signaling influences the production of pro-resolving and pro-inflammatory lipid mediators in alveolar macrophages derived from individuals with asthma.

Few new therapeutics exist to target airway inflammation in mild-to-moderate asthma. Alveolar macrophages regulate airway inflammation by producing proresolving eicosanoids. We hypothesized that stimulation of the purinergic receptor P2X7 in macrophages from individuals with asthma produces eicosanoids associated with airway inflammation and resolution, and that these responses are predicted, in part, by P2X7 pore function. Study subjects were recruited in an Institutional Review Board (IRB)-approved study. Alveolar macrophages were recovered from bronchoalveolar lavage fluid following bronchoscopy. Purinergic receptor classification was performed using flow cytometry and fluorescent cell assay. Macrophages were stimulated in vitro and eicosanoids were measured via ELISA or enzyme immunoassay (EIA) in the presence and absence of P2X7-specific agonist [2'(3')-O-(4-Benzoylbenzoyl)adenosine-5'-triphosphate tri(triethylammonium) salt (Bz-ATP)] and antagonist (AZD9056). Functional P2X7 pore status was confirmed in a live cell assay using P2X7-specific agonists and antagonists. Alveolar macrophages produced increased quantities of the oxylipins lipoxin A4 (LXA4), resolvin D1 (RvD1), and 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE) following stimulation with Bz-ATP compared with vehicle controls, responses that were attenuated in the presence of the P2X7-selective antagonist, AZD9056. LXA4 and RvD1 production was greatest at 1 h, whereas 15(S)-HETE was maximally produced 24 h. Prostaglandin E-2 and resolvin E1 were minimally produced by P2X7 activation, indicating differential signaling pathways involved in eicosanoid production in alveolar macrophages derived from individuals with asthma. The early production of the proresolving eicosanoids, LXA4 and resolvin D1, is regulated by P2X7, whereas generation of the proinflammatory eicosanoid, 15(S)-HETE, is only partially regulated through P2X7 signaling and reaches maximal production after the peak in proresolving eicosanoids.NEW & NOTEWORTHY Alveolar macrophages obtained from individuals with asthma produce soluble lipid mediators in response to P2X7 purinergic receptor signaling. Proinflammatory mediators may contribute to asthma exacerbations but proresolving mediators may help with resolution of asthma loss of control. These specialized proresolving lipid mediators may serve as future potential therapeutics for asthma exacerbation resolution and recovery.

The aryl hydrocarbon receptor regulates lipid mediator production in alveolar macrophages.

Allergic inflammation of the airways such as allergic asthma is a major health problem with growing incidence world-wide. One cardinal feature in severe type 2-dominated airway inflammation is the release of lipid mediators of the eicosanoid family that can either promote or dampen allergic inflammation. Macrophages are key producers of prostaglandins and leukotrienes which play diverse roles in allergic airway inflammation and thus require tight control. Using RNA- and ATAC-sequencing, liquid chromatography coupled to mass spectrometry (LC-MS/MS), enzyme immunoassays (EIA), gene expression analysis and in vivo models, we show that the aryl hydrocarbon receptor (AhR) contributes to this control via transcriptional regulation of lipid mediator synthesis enzymes in bone marrow-derived as well as in primary alveolar macrophages. In the absence or inhibition of AhR activity, multiple genes of both the prostaglandin and the leukotriene pathway were downregulated, resulting in lower synthesis of prostanoids, such as prostaglandin E2 (PGE2), and cysteinyl leukotrienes, e.g., Leukotriene C4 (LTC4). These AhR-dependent genes include PTGS1 encoding for the enzyme cyclooxygenase 1 (COX1) and ALOX5 encoding for the arachidonate 5-lipoxygenase (5-LO) both of which major upstream regulators of the prostanoid and leukotriene pathway, respectively. This regulation is independent of the activation stimulus and partially also detectable in unstimulated macrophages suggesting an important role of basal AhR activity for eicosanoid production in steady state macrophages. Lastly, we demonstrate that AhR deficiency in hematopoietic but not epithelial cells aggravates house dust mite induced allergic airway inflammation. These results suggest an essential role for AhR-dependent eicosanoid regulation in macrophages during homeostasis and inflammation.

UGRP1-modulated MARCO+ alveolar macrophages contribute to age-related lung fibrosis

The aging lungs are vulnerable to chronic pulmonary diseases; however, the underlying mechanisms are not well understood. In this study, we compared the aging lungs of 20–24-month-old mice with the young of 10–16-week-old mice, and found that aging airway epithelial cells significantly upregulated the expression of uteroglobin-related protein 1 (UGRP1), which was responsible for the higher levels of CCL6 in the aging lungs. Alveolar macrophages (AMs) changed intrinsically with aging, exhibiting a decrease in cell number and altered gene expression. Using terminal differentiation trajectories, a population of MARCO+ AMs with the ability to produce CCL6 was identified in the aging lungs. Upregulated UGRP1was demonstrated to modulate CCL6 production of AMs in the UGRP1-MARCO pair in vivo and in vitro. Furthermore, MARCO+ AMs aggravated bleomycin-induced pulmonary fibrosis in a CCL6-dependent manner in the aged mice, and blocking MARCO or neutralizing CCL6 significantly inhibited pulmonary fibrosis, similar to the depletion of AMs. The age-related upregulation of UGRP1 and MARCO+ AMs, involved in the progression of lung fibrosis, was also observed in human lung tissues. Thus, UGRP1 modulated MARCO+ AMs regarding the age-related lung fibrosis in a CCL6-dependent manner, which is key to establishing optimal targeting for the aging population.

African Swine Fever Virus L83L Negatively Regulates the cGAS-STING-Mediated IFN-I Pathway by Recruiting Tollip To Promote STING Autophagic Degradation.

African swine fever (ASF) is a devastating infectious disease of pigs caused by the African swine fever virus (ASFV), which poses a great danger to the global pig industry. Many viral proteins can suppress with interferon signaling to evade the host's innate immune responses. Therefore, the development of an effective vaccine against ASFV has been dampened. Recent studies have suggested that the L83L gene may be integrated into the host genome, weakening the host immune system, but the underlying mechanism is unknown. Our study found that L83L negatively regulates the cGAS-STING-mediated type I interferon (IFN-I) signaling pathway. Overexpression of L83L inhibited IFN-β promoter and ISRE activity, and knockdown of L83L induced higher transcriptional levels of interferon-stimulated genes (ISGs) and phosphorylation levels of IRF3 in primary porcine alveolar macrophages. Mechanistically, L83L interacted with cGAS and STING to promote autophagy-lysosomal degradation of STING by recruiting Tollip, thereby blocking the phosphorylation of the downstream signaling molecules TBK1, IRF3, and IκBα and reducing IFN-I production. Altogether, our study reveals a negative regulatory mechanism involving the L83L-cGAS-STING-IFN-I axis and provides insights into an evasion strategy involving autophagy and innate signaling pathways employed by ASFV. IMPORTANCE African swine fever virus (ASFV) is a large double-stranded DNA virus that primarily infects porcine macrophages. The ASFV genome encodes a large number of immunosuppressive proteins. Current options for the prevention and control of this pathogen remain pretty limited. Our study showed that overexpression of L83L inhibited the cGAS-STING-mediated type I interferon (IFN-I) signaling pathway. In contrast, the knockdown of L83L during ASFV infection enhanced IFN-I production in porcine alveolar macrophages. Additional analysis revealed that L83L protein downregulated IFN-I signaling by recruiting Tollip to promote STING autophagic degradation. Although L83L deletion has been reported to have little effect on viral replication, its immune evade mechanism has not been elucidated. The present study extends our understanding of the functions of ASFV-encoded pL83L and its immune evasion strategy, which may provide a new basis for developing a live attenuated vaccine for ASF.

In Vitro, In Vivo and In Silico Assessment of the Antimicrobial and Immunomodulatory Effects of a Water Buffalo Cathelicidin (WBCATH) in Experimental Pulmonary Tuberculosis.

Tuberculosis (TB) is considered the oldest pandemic in human history. The emergence of multidrug-resistant (MDR) strains is currently considered a serious global health problem. As components of the innate immune response, antimicrobial peptides (AMPs) such as cathelicidins have been proposed to have efficacious antimicrobial activity against Mycobacterium tuberculosis (Mtb). In this work, we assessed a cathelicidin from water buffalo, Bubalus bubalis, (WBCATH), determining in vitro its antitubercular activity (MIC), cytotoxicity and the peptide effect on bacillary loads and cytokines production in infected alveolar macrophages. Our results showed that WBCATH has microbicidal activity against drug-sensitive and MDR Mtb, induces structural mycobacterial damage demonstrated by electron microscopy, improves Mtb killing and induces the production of protective cytokines by murine macrophages. Furthermore, in vivo WBCATH showed decreased bacterial loads in a model of progressive pulmonary TB in BALB/c mice infected with drug-sensitive or MDR mycobacteria. In addition, a synergistic therapeutic effect was observed when first-line antibiotics were administered with WBCATH. These results were supported by computational modeling of the potential effects of WBCATH on the cellular membrane of Mtb. Thus, this water buffalo-derived cathelicidin could be a promising adjuvant therapy for current anti-TB drugs by enhancing a protective immune response and potentially reducing antibiotic treatment duration.

Calcaratarin D, a labdane diterpenoid, attenuates mouse asthma via modulating alveolar macrophage function.

Alveolar macrophages (AMs) contribute to airway inflammation and remodelling in allergic asthma. Calcaratarin D (CalD), a labdane diterpenoid from rhizomes of the medicinal plant Alpinia calcarata, has recently been shown to possess anti-inflammatory properties. The present study evaluated protective effects of CalD in a house dust mite (HDM)-induced asthma mouse model. The effects of CalD on AMs in contributing to anti-inflammatory effects in asthma were investigated through in vivo, ex vivo, and in vitro experiments. CalD reduced total bronchoalveolar lavage fluid and differential cell count, serum IgE levels, mucus hypersecretion, and airway hyperresponsiveness in HDM-challenged mice. Additionally, CalD affected a wide array of pro-inflammatory cytokines and chemokines and oxidative damage markers in isolated lung tissues. CalD suppressed the HDM-induced increase in Arg1 (M2 macrophage marker) in AMs from lung tissue and reduced lung polyamine levels. CalD weakened antigen presentation capability of AMs by reducing CD80 expression, reduced AM-derived CCL17 and CCL22 levels, and lessened Th2 cytokines from CD4+ T-cells from asthma lung digest. CalD blocked the HDM-induced FoxO1/IRF4 pathway and restored impaired the Nrf2/HO-1 antioxidant pathway in lung tissues. CalD inhibited IL-4/IL-13-stimulated JAK1/STAT6 pathway, FoxO1 protein expression, and chemokine production in primary AMs. Structure-activity relationship study revealed the α,β-unsaturated γ-butyrolactone in CalD is capable of forming covalent bonds with cellular protein targets essential for its action. Our results demonstrate for the first time that CalD is a novel anti-inflammatory natural compound for allergic asthma that modulates AM function.

Pseudomonas aeruginosa Elicits Sustained IL-1β Upregulation in Alveolar Macrophages from Lung Transplant Recipients

<h3>Purpose</h3> Clinical infection or colonization of the lung, specifically with <i>Pseudomonas aeruginosa</i> (<i>PsA</i>), is associated with increased incidence of lung allograft injury in lung transplant recipients (LTRs) and with an increase in BAL (bronchoalveolar lavage) pro-inflammatory cytokines. However, the effect of bacterial colonization on sustained innate immune activation and the mechanisms involved are not well understood. We sought to determine the mechanisms underlying persistent pro-inflammatory alveolar macrophage response to <i>PsA</i> stimulation. <h3>Methods</h3> We stimulated THP-1 derived macrophages and BAL-derived alveolar macrophages from LTRs with bacteria representative of infectious pathogens and upper respiratory commensals for up to 96 hours. Using a high dimensional flow cytometry panel, we evaluated macrophage responses including expression of costimulatory molecules (CD80, CD86, CD40); co-inhibitor molecules (B7-H1), pro-inflammatory cytokines (TNF-α, IL-6, IL-8, IL-1β), and anti-inflammatory mediators (IL-10, IL-1RA, and TGF-β). <h3>Results</h3> We observed an upregulation of pro-inflammatory cytokines (TNF-α, IL-6, IL-8, IL-1β) following stimulation by <i>PsA</i> compared to stimulation with other pathogens (<i>Staphylococcus aureus</i>) and oral-commensal bacteria (<i>Prevotella melaninogenica, Streptococcus pneumoniae</i>) in THP-1 macrophages. IL-1 β elevations were sustained for 96 hours after <i>PsA</i> exposure. Alveolar macrophages from LTRs undergoing surveillance bronchoscopy demonstrated elevated levels of IL-6 and showed a similar IL-1β responses to that observed in THP-1 macrophages when exposed to <i>PsA</i>. <h3>Conclusion</h3> <i>PsA</i> induces a sustained increase in IL-1β production in alveolar macrophages from LTRs. Given the prior described role of IL-1β in lung allograft injury and CLAD, further investigations are ongoing to determine clinical correlates of allograft injury with <i>PsA</i> and IL-1β.

AMFR drives allergic asthma development by promoting alveolar macrophage–derived GM-CSF production

Alveolar macrophages (AMs) are specialized tissue-resident macrophages that orchestrate the immune response in allergic inflammation and asthma. However, what signals direct AMs to cross talk with other immune cells remains unclear. Here, we report that autocrine motility factor receptor (AMFR), an endoplasmic reticulum-resident E3 ubiquitin ligase, is upregulated in AMs of asthma and is critical for this condition. AMFR deficiency significantly decreased allergy-induced T helper 2 (Th2) and eosinophilic inflammation, with less granulocyte-macrophage colony-stimulating factor (GM-CSF) production in AMs. Mechanistically, following thymic stromal lymphopoietin (TSLP) stimulation, AMFR associated directly with cytokine-inducible SH2-containing protein (CIS), induced the ubiquitination of Lys48-linked polyubiquitination of CIS, and consequently blocked the inhibitory effect of CIS on signal transducer and activator of transcription 5 (STAT5) phosphorylation and the downstream pathway activation in AMs. In conclusion, our results demonstrate that AMFR serves a crucial role in promoting inflammation in asthma through regulating AM function, and may emerge as a new potential drug target for asthma therapy.

African Swine Fever Virus pI215L Negatively Regulates cGAS-STING Signaling Pathway through Recruiting RNF138 to Inhibit K63-Linked Ubiquitination of TBK1.

African swine fever is a severe animal infectious disease caused by African swine fever virus (ASFV), and the morbidity and mortality associated with virulent ASFV isolates are as high as 100%. Previous studies showed that the ability of ASFV to antagonize IFN production is closely related to its pathogenicity. Here, we report that ASFV HLJ/18 infection induced low levels of type I IFN and inhibited cGMP-AMP-induced type I IFN production in porcine alveolar macrophages that were isolated from specific pathogen-free Landrace piglets. Subsequently, an unbiased screen was performed to screen the ASFV genes with inhibitory effects on the type I IFN production. ASFV pI215L, a viral E2 ubiquitin-conjugating enzyme, was identified as one of the strongest inhibitory effectors on the production of type I IFN. Knockdown of pI215L expression inhibited ASFV replication and enhanced IFN-β production. However, inhibition of type I IFN production by pI215L was independent of its E2 enzyme activity. Furthermore, we found that pI215L inhibited type I IFN production and K63-linked polyubiquitination of TANK-binding kinase 1 through pI215L-binding RING finger protein 138 (RNF138). ASFV pI215L enhanced the interaction between RNF138 and RNF128 and promoted RNF138 to degrade RNF128, which resulted in reduced K63-linked polyubiquitination of TANK-binding kinase 1 and type І IFN production. Taken together, our findings reveal a novel immune escape mechanism of ASFV, which provides a clue to the design and development of an immune-sensitive attenuated live vaccine.

Curcumin inhibition of bleomycin-induced changes in lung collagen synthesis, deposition and assembly.

Idiopathic pulmonary fibrosis is characterized by progressive lung tissue remodeling and disproportionate deposition of collagenous proteins with limited therapeutic interventions. The purpose of this study was to determine whether curcumin inhibits bleomycin (BLM)-induced increases in synthesis, degradation and cross-linking of lung collagen in rats. Following a single intratracheal instillation of BLM to rats (0.75 U/100g, sacrificed 3, 5, 7, 14 and 28days post-BLM), lung collagen synthesis (determined by incorporation of 3H-proline) and deposition (determined by lung hydroxyproline content) progressively increased at days 7, 14 and 28 post-BLM injection. Lung lavage fluid hydroxyproline and collagenase levels (a measure of collagen turnover) were increased in BLM rats compared with control groups. In addition, BLM instillation resulted in increased concentrations of collagenase and collagenolytic cathepsin in the lungs. Furthermore, increased cross-linking (as determined by aldehyde content of acid soluble collagen), and decreased susceptibility of fibrotic lung insoluble collagen to denaturing agents occurred in BLM-injured lungs. Significant increases in alveolar macrophage (AM) release of transforming growth factor-β1 (TGF-β1) were noted at various time points (days 3, 5, 7, 14 and 28 post-BLM) during the development and progression of lung fibrosis in rats. Curcumin treatment to BLM rats (300mg/kg 10days before and daily thereafter throughout the experimental time period) was associated with marked reductions in lung collagen synthesis and deposition, BALF and lung collagenase activity, BALF hydroxyproline content and lung collagenolytic levels. Additionally, reduced levels of collagen cross-linking and enhanced susceptibility of insoluble lung collagen to denaturing agents were observed in curcumin-treated BLM rats. Finally, curcumin inhibited BLM-induced increases in AM production of TGF-β1. Our data demonstrate for the first time that curcumin prevents fibrotic deposits by modulating collagen turnover, assembly and deposition in BLM-instilled rat lungs, and that curcumin treatment protects against BLM activation of macrophages by suppressing the release of TGF-β1.

PCO-002 - Effect of Lonicera caerulea on cytokine production of alveolar macrophages by stimulation with SARS-CoV-2-related proteins

PCO-002 - Effect of Lonicera caerulea on cytokine production of alveolar macrophages by stimulation with SARS-CoV-2-related proteins

Features of cytokine production in tumor associated with metastasis and basal cell hyperplasia of bronchial epithelium in non-small cell lung cancer

The emergence and progression of a tumor (relapses, metastasis) is largely due to the presence and nature of inflammatory processes. It is promising to clarify the pathogenetic role and prognostic value of cytokines involved in the inflammation. The basal cell hyperplasia in the bronchial epithelium adjacent to the tumor may be associated with inflammation in the tumor microenvironment. Objective: to study the production of inflammatory cytokines in the tumor, taking into account basal cell hyperplasia in the bronchial epithelium adjacent to the tumor in the patients with nonsmall cell lung cancer. 35 patients with non-small cell lung cancer (T1-3N0-2M0) were included in the study. Neoadjuvant chemotherapy was administered in 17 cases. The production of TGF-β, TNF-α, SDF-1, VEGFA was determined by immunohistochemistry in tumor cells and alveolar macrophages. Basal cell hyperplasia in the bronchi adjacent to the tumor was morphologically diagnosed. The absence of SDF-1 in the nuclei of tumor cells was associated with the hematogenous metastases in patients with BCH of the bronchi adjacent to the tumor. Basal cell hyperplasia is correlated with an increased TGF-β production in alveolar macrophages and a decreased of SDF-1 in the cytoplasm of tumor cells. The frequency of case TNF-α in alveolar macrophages is reduced in patients with hematogenous metastases who received neoadjuvant chemotherapy. Cytokine production in the tumor cells and leukocytes was associated with the hematogenous metastases, taking into account the basal cell hyperplasia, which is associated with the pro-inflammatory cytokines in the tumor. The effects of neoadjuvant chemotherapy differ depending hematogenous metastasis.

Relative Contributions of PM2.5 Chemical Constituents to Overall ROS Production in Alveolar Macrophages

Identifiable links have been established between ambient atmospheric particulate matter (PM) exposure and adverse health effects in humans. PM2.5 poses significant risk to the respiratory system of humans, triggering inflammatory responses at the distal ends of the tract upon interaction with alveolar macrophages (AM). Understanding the contribution of organelle-specific ROS production is imperative to developing treatments tailored to combat cellular oxidative stress. Furthermore, an analysis of the relative contributions of each constituent compound to the generation of ROS is necessary to understand the proportionate toxicities of each PM2.5 component. Past iterations of the study succeeded in quantifying the oxidative stress potential of PM2.5 samples originating from filters collected from Fresno and Claremont during summer and winter. PM2.5 collected was demonstrated to induce varying ROS responses in NR8383 AM, revealing sample origin as a factor in ROS production, and strongly suggesting that chemical composition of PM2.5 is a major determinant of AM ROS generation. We elected to study two commonly PM2.5 -occurring cyclic diones (9,10 phenanthrenequinone and 1,4 naphthoquinone) and two commonly occurring transition metals (Cu2+ and Fe2+ ) for their propensity to generate oxidative stress within a cellular context. Analysis of stress response in AM established that cells treated with quinones reached a peak intracellular ROS level at comparatively lower treatment concentrations than cells treated with transition metals. As previously hypothesized, results reaffirmed the notion that organic compounds possess substantially higher stress potential than either transition metal, limited by lower environmental concentrations, and identified Iron (II) to be the principal contributor to oxidative stress responses at nearly every site.

SARS‐CoV‐2 evades immune detection in alveolar macrophages

Respiratory infections, like the current COVID‐19 pandemic, target epithelial cells in the respiratory tract. Alveolar macrophages (AMs) are tissue‐resident macrophages located within the lung. They play a key role in the early phases of an immune response to respiratory viruses. AMs are likely the first immune cells to encounter SARS‐CoV‐2 during an infection, and their reaction to the virus will have a profound impact on the outcome of the infection. Interferons (IFNs) are antiviral cytokines and among the first cytokines produced upon viral infection. In this study, AMs from non‐infectious donors are challenged with SARS‐CoV‐2. We demonstrate that challenged AMs are incapable of sensing SARS‐CoV‐2 and of producing an IFN response in contrast to other respiratory viruses, like influenza A virus and Sendai virus, which trigger a robust IFN response. The absence of IFN production in AMs upon challenge with SARS‐CoV‐2 could explain the initial asymptotic phase observed during COVID‐19 and argues against AMs being the sources of pro‐inflammatory cytokines later during infection.

Stimulation of Phagocytosis in Alveolar Macrophages and Resistance against Infection in Mice by the Aqueous Extract of Rhizomes of Aframomum danielli, Schum (zingiberaceae)

Background: Alveolar Macrophages (AMs) play important role in preservation of lungs from infectious diseases development through a series of activities including phagocytosis. The present study examined the effects of aqueous extract of Aframomum danielli rhizomes on the AMs functions. Methods: Extract was investigated for microbe’s ingestion, bacteria killing and reactive oxygen and nitrogen species production in alveolar macrophages. Extract was investigated for repository, suppressive and curative treatments of S. aureus infection in mice. Results: The extract of Aframomum danielli augmented (approximately threefold) the ingestion of Candida albicans by phagocytes. Furthermore, extract concentration dependently increased the killing ability of S. aureus of mice AMs. Moreover, the extract significantly stimulated the production of O2, H2O2 and nitric oxide (NO) by mice AMs. In addition, extract make mice to become more resistant to S. aureus infection. Finally, aqueous extract of A. danielli dose dependently increased reduced the bacteremia density in Dex-mice in suppressive, curative and repository treatments. Conclusion: Together the results showed that aqueous extract of A. dalnielli promotes the phagocytosis of microbes by alveolar macrophages and thereby may contribute to respiratory tract prevention from bacterial colonization.

Penehyclidine hydrochloride inhibits renal ischemia/reperfusion-induced acute lung injury by activating the Nrf2 pathway.

The nuclear factor (NF)-κB and NOD-like receptor protein 3 (NLRP3) pathways promote inflammatory signaling that injures the kidneys, whereas the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway promotes anti-inflammatory signaling that inhibits oxidative damage. Penehyclidine hydrochloride (PHC) inhibits NF-κB and activates Nrf2 signaling. We investigated whether PHC induces communication between the Nrf2 and NF-κB/NLRP3 pathways, thereby protecting against renal ischemia/reperfusion (rI/R)-induced lung inflammation. Rat alveolar macrophages (NR8383 cells) were stimulated for 24 h with PHC with or without brusatol (a Nrf2 antagonist), after which they were treated for 4 h with tert-butyl hydroperoxide (10 mM). PHC Nrf2-dependently alleviated tert-butyl hydroperoxide-induced reactive oxygen species production in alveolar macrophages. Additionally, wild-type and Nrf2−/− rats were each divided into four groups: (1) sham, (2) PHC (1 mg/kg), (3) rI/R and (4) rI/R + PHC (1 mg/kg). PHC markedly induced the Nrf2 and adenosine monophosphate-activated protein kinase pathways and suppressed rI/R-induced NF-κB and NLRP3 activation in the lungs. Nrf2 deficiency diminished the ability of PHC to ameliorate rI/R-induced histopathological alterations and reactive oxygen species release in the lungs; however, PHC inhibited NLRP3 signaling Nrf2-dependently, while it inhibited NF-κB signaling Nrf2-independently. Our findings demonstrate the beneficial effects of PHC on rI/R-induced lung inflammation.

Essential Role of Indoleamine 2, 3-dioxygenase 1 (IDO1) in Metabolic Programming of Innate Immune Responses in Aged Lung during Influenza

Abstract Influenza remains a leading cause of morbidity and mortality, with highest incidence of hospitalization and death occurring in persons &amp;gt;65 years of age. The goal of this study was to interrogate biochemical profiles manifested in lung tissue originating from young adult and aged adult mice over the course of infection, with the aim of characterizing metabolic migration in lung during influenza. There was heightened inflammation, cellular infiltration, and alveolitis present in the aged lung that corresponded with increased viral titers, morbidity, and mortality. Focusing on the biochemical and pathway changes illustrated an important role for kynurenine and tryptophan metabolism in modulating lung specific immune responses to influenza. There was a significant decrease in kynurenine production in aged alveolar macrophages by day 7 post influenza infection that was associated with increased inflammatory and diminished regulatory responses. Despite a rapid increase in IDO1 expression in young, there was impaired expression and activity in aged macrophages and lung during the course of infection. Age-associated mitochondrial dysfunction contributed to changes in IDO1 expression and decreased kynurenine production in aged lung and alveolar macrophages and resulted in alternate immunometabolic signaling and heightened pro-inflammatory responses. Treatment with a mitochondrial targeted antioxidant improved IDO1 mediated production of kynurenine as well as ameliorated mortality in aged mice. Taken together, our data provide additional evidence as to why older persons are more susceptible to influenza and suggest a possible therapeutic to improve immunometabolic responses in this population.