ABSTRACT
Resident-tissue macrophages (RTMs) arise from embryonic precursors1,2, yet the developmental signals that shape their longevity remain largely unknown. Here we demonstrate in mice genetically deficient in 12-lipoxygenase and 15-lipoxygenase (Alox15-/- mice) that neonatal neutrophil-derived 12-HETE is required for self-renewal and maintenance of alveolar macrophages (AMs) during lung development. Although the seeding and differentiation of AM progenitors remained intact, the absence of 12-HETE led to a significant reduction in AMs in adult lungs and enhanced senescence owing to increased prostaglandin E2 production. A compromised AM compartment resulted in increased susceptibility to acute lung injury induced by lipopolysaccharide and to pulmonary infections with influenza A virus or SARS-CoV-2. Our results highlight the complexity of prenatal RTM programming and reveal their dependency on in trans eicosanoid production by neutrophils for lifelong self-renewal.
Subject(s)
12-Hydroxy-5,8,10,14-eicosatetraenoic Acid , Cell Self Renewal , Macrophages, Alveolar , Neutrophils , Animals , Mice , 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid/metabolism , Acute Lung Injury , Animals, Newborn , Arachidonate 12-Lipoxygenase/deficiency , Arachidonate 15-Lipoxygenase/deficiency , COVID-19 , Influenza A virus , Lipopolysaccharides , Lung/cytology , Lung/virology , Macrophages, Alveolar/cytology , Macrophages, Alveolar/metabolism , Neutrophils/metabolism , Orthomyxoviridae Infections , Prostaglandins E , SARS-CoV-2 , Disease SusceptibilityABSTRACT
In this review it is attempted to summarize current studies about formation of eicosanoids and other oxylipins in different human macrophages. There are several reports on M1 and M2 cells, also other phenotypes have been described. The eicosanoids formed in the largest amounts are the COX products TxB2 and PGE2. Thus shortlived bioactive TxA2 is a dominating product both in M1- and in M2-lineages, one exception seems to be MGM-CSF, TGFß cells. 5-LOX products are produced in both M1 and M2 macrophages, as well as in not fully polarized cells of both lineages. MM-CSF as well as M2 macrophages produced LTC4 more readily compared to M1 lineage cells. In MGM-CSF, TGFß cells LTB4 is a major eicosanoid, in line with high expression of LTA4 hydrolase. Recent reports described increased formation of leukotrienes in macrophages subjected to trained immunity with inflammatory transcriptional reprogramming. Also in macrophages derived from monocytes collected from post-COVID-19 patients. 15-LOX-1 is strongly upregulated in CD206+ M2 cells (M2a), differentiated in presence of IL-4. These macrophages also express 15-LOX-2. In incubations with pathogenic E. coli as well as other stimuli 15(S)-HETE and 17(S)-HDHA were major oxylipins formed. Also, the SPM precursor 5,15-diHETE and the SPM RvD5 were produced in considerable amounts, while other SPMs were less abundant. In M2 macrophages incubated with E. coli or S. aureus the cytosolic 15-LOX-1 enzyme accumulated to punctuate structures in a Ca2+ dependent manner with a relatively slow time course, leading to formation of mediators from endogenous substrate. Chalcones, flavone-like anti-inflammatory natural products, induced translocation of 15-LOX-1 in M2 cells, with high formation of 15-LOX derived oxylipins.
Subject(s)
Biological Products , Eicosanoids , Macrophages , Oxylipins , Arachidonate 5-Lipoxygenase/metabolism , Biological Products/metabolism , COVID-19 , Chalcones , Cyclooxygenase 2/metabolism , Eicosanoids/metabolism , Escherichia coli/metabolism , Flavones , Granulocyte-Macrophage Colony-Stimulating Factor/metabolism , Humans , Hydrolases/metabolism , Hydroxyeicosatetraenoic Acids/metabolism , Interleukin-4/metabolism , Leukotrienes , Macrophage Colony-Stimulating Factor , Macrophages/metabolism , Oxylipins/metabolism , Prostaglandins E/metabolism , Scavenger Receptors, Class E/metabolism , Staphylococcus aureus , Transforming Growth Factor beta/metabolismABSTRACT
OBJECTIVE: The aim of this in vitro study was to investigate the expression of SARS-CoV-2 entry and processing genes in human gingival fibroblasts (HGnF) following treatment with Porphyromonas gingivalis-derived lipopolysaccharide (PgLPS) or inflammatory cytokines/mediators. DESIGN: We assessed the expression of SARS-CoV-2 entry and processing genes; angiotensin-converting enzyme 2 (ACE2), cellular serine proteases transmembrane serine protease 2 (TMPRSS2), Furin, and basigin (BSG) in HGnF by real-time PCR. To further asses the contribution of PgLPS and inflammatory cytokines/mediators to proliferation and SARS-CoV-2 entry and processing gene expression, HGnF were treated with PgLPS, IL1ß, TNFα, and PGE2. RESULTS: The expression for ACE2 in HGnF was significantly elevated after PgLPS or IL1ß, TNFα, PGE2 treatment. The expression of TMPRSS2 was increased by PgLPS, IL1ß, or PGE2 while BSG was elevated by PgLPS and IL1ß. The expression of BSG and FURIN decreased after TNFα treatment. CONCLUSION: SARS-CoV-2 entry and processing genes are expressed in human gingival fibroblasts and their expressions are altered by PgLPS, IL1ß, TNFα and PGE2 treatment.