scholarly journals SARS-CoV-2 Spike S1 glycoprotein is a TLR4 agonist, upregulates ACE2 expression and induces pro-inflammatory M1 macrophage polarisation.

2021 ◽  
Author(s):  
Mohamed M Aboudounya ◽  
Mark R Holt ◽  
Richard J Heads
Keyword(s):  
Viral Entry ◽  
Human Cells ◽  
Cardiac Complications ◽  
Macrophage Phenotype ◽  
Macrophage Polarisation ◽  
Proximity Ligation ◽  
M1 Macrophage ◽  
Tlr4 Agonist ◽  
Ifn Γ ◽  
Tlr4 Activation

Background and aims: TLR4 is an important innate immune receptor that recognizes bacterial LPS, viral proteins and other pathogen associated molecular patterns (PAMPs). It is expressed on tissue-resident and immune cells. We previously proposed a model whereby SARS-CoV-2 activation of TLR4 via its spike glycoprotein S1 domain increases ACE2 expression, viral loads and hyperinflammation with COVID-19 disease [1]. Here we test this hypothesis in vitro and demonstrate that the SARS-CoV-2 spike S1 domain is a TLR4 agonist in rat and human cells and induces a pro-inflammatory M1 macrophage phenotype in human THP-1 monocyte-derived macrophages. Methods: Adult rat cardiac tissue resident macrophage-derived fibrocytes (rcTMFs) were treated with either bacterial LPS or recombinant SARS-CoV-2 spike S1 glycoprotein. The expression of ACE2 and other inflammatory and fibrosis markers were assessed by immunoblotting. S1/TLR4 co-localisation/binding was assessed by immunocytochemistry and proximity ligation assays on rcTMFs and human HEK-293 HA-TLR4-expressing cells. THP-1 monocytes were differentiated into M1 or M2 macrophages with LPS/IFN-γ, S1/IFN-γ or IL-4 and RNA was extracted for RT-qPCR of M1/M2 markers and ACE2. Results: TLR4 activation by spike S1 or LPS resulted in the upregulation of ACE2 in rcTMFs as shown by immunoblotting. Likewise, spike S1 caused TLR4-mediated induction of the inflammatory/wound healing marker COX-2 and concomitant downregulation of the fibrosis markers CTGF and Col3a1, similar to LPS. The specific TLR4 TIR domain signalling inhibitor CLI-095 (Resatorvid), blocked the effects of spike S1 and LPS, confirming that spike S1 is a TLR4 agonist and viral PAMP (VAMP). ACE2 expression was also inhibited by the dynamin inhibitor Dynasore, suggesting ACE2 expression is mediated by the alternative endosomal/β-interferon pathway. Confocal immunofluorescence microscopy confirmed 1:1 stoichiometric spike S1 co-localisation with TLR4 in rat and human cells. Furthermore, proximity ligation assays confirmed spike S1 and TLR4 binding in human and rat cells. Spike S1/IFN-γ treatment of THP-1-derived macrophages induced pro-inflammatory M1 polarisation as shown by an increase in IL-1-β and IL-6 mRNA. Conclusions: These results confirm that TLR4 is activated by the SARS-CoV-2 spike protein S1 domain and therefore TLR4 may be a receptor/accessory factor for the virus. By binding to and activating TLR4, spike S1 caused upregulation of ACE2, which may facilitate viral entry into cells. In addition, pro-inflammatory M1 macrophage polarisation via TLR4 activation, links TLR4 activation by spike S1 to inflammation. The clinical trial testing of CLI-095 (Resatorvid) and other TLR4 antagonists in severe COVID-19, to reduce both viral entry into cells and hyperinflammation, is warranted. Our findings likely represent an important development in COVID-19 pathophysiology and treatment, particularly regarding cardiac complications and the role of macrophages.

Abstract 157: Toll like Receptor 4 Activation Promotes Cardiac Arrhythmias By Decreasing The Transient Outward Potassium Current (ito) Through An Irf3 dependent And Myd88 independent Pathway

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Emiliano Medei ◽  
Gustavo Monnerat-Cahli ◽  
Hiart Alonso ◽  
Monica Gallego ◽  
Micaela Lopez Alarcon ◽  
...  
Keyword(s):  
Cardiac Arrhythmias ◽  
Ventricular Myocytes ◽  
Cardiac Complications ◽  
Electrical Remodeling ◽  
Toll Like Receptor 4 ◽  
Triggered Activity ◽  
Tlr4 Agonist ◽  
Action Potential Prolongation ◽  
Tlr4 Activation

Cardiac arrhythmias are one of the main causes of death worldwide. Several studies have shown that inflammation plays a key role in different cardiac diseases and Toll like receptors (TLR’s) play an important role in cardiac complications. In the present study, we investigated whether the activation of TLR4 induces cardiac electrical remodeling and arrhythmias. Also the signaling pathway involved in these phenomena was studied. Action potentials, the presence of cardiac arrhythmias and transient outward K + current (I to ) were recorded in Wistar rat’s hearts after 24 h exposure to the TLR4 agonist ultrapure Lipopolysaccharide (LPS - 1μg/ml). TLR4 stimulation in vitro promotes a cardiac electrical remodeling that leads to cardiac action potential prolongation which evokes arrhythmic events such as delayed after depolarization (DAD's) and triggered activity. The perfusion of LPS (1μg/ml) during 30 minutes did not modify I to . Conversely, after 24 h of LPS incubation I to was reduced, with no changes in the biophysical properties of the current. Major changes in Ca 2+ cycling were not observed in ventricular myocytes after 24 h exposure to LPS; however, extrasystolic activity was present in a considerable number of cells (25%). Neither the blockade of Interleulink-1 receptor-associated kinase 4 nor nuclear factor kappa B (NF-kB) prevented the LPS effect on I to . However, interferon regulatory factor 3 (IRF3) inhibition prevented the effect of TLR4 activation on I to . Activation of TLR4 induced extrasystolic activity, longer AP duration and evoked DAD's and triggered activity because of a reduction in I to . The mechanism involved is MyD88-independent and IRF3-dependent.

scholarly journals IRF5 Is a Specific Marker of Inflammatory MacrophagesIn Vivo

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Miriam Weiss ◽  
Katrina Blazek ◽  
Adam J. Byrne ◽  
Dany P. Perocheau ◽  
Irina A. Udalova
Keyword(s):  
Specific Marker ◽  
M2 Macrophages ◽  
Macrophage Phenotype ◽  
Tissue Remodelling ◽  
Murine Bone Marrow ◽  
Macrophage Polarisation ◽  
M1 Macrophage ◽  
Anti Inflammatory

Macrophages are an integral part of the innate immune system and key players in pathogen clearance and tissue remodelling. Both functions are accomplished by a pivotal network of different macrophage subtypes, including proinflammatory M1 and anti-inflammatory M2 macrophages. Previously, our laboratory identified the transcription factor interferon regulatory factor 5 (IRF5) as the master regulator of the M1 macrophage polarisation. IRF5 was found to be highly expressed in human M1 compared to M2 macrophages. Furthermore, IRF5 dictates the expression of proinflammatory genes such asIL12bandIL23awhilst repressing anti-inflammatory genes likeIL10. Here we show that murine bone marrow derived macrophages differentiatedin vitrowith GM-CSF are also characterised by high levels of IRF5 mRNA and protein and express proinflammatory cytokines upon LPS stimulation. These macrophages display characteristic expression of M1-marker MHC II but lack the M2-marker CD206. Significantly, we develop intracellular staining of IRF5- expressing macrophages and utilise it to recapitulate thein vitroresults in anin vivomodel of antigen-induced arthritis, emphasising their physiological relevance. Thus, we establish the species-invariant role of IRF5 in controlling the inflammatory macrophage phenotype bothin vitroand inin vivo.

scholarly journals М3 макрофаги останавливают деление клеток предстательной железы больного раком простаты

2020 ◽  
Author(s):  
S.V. Kalish ◽  
S.V. Lyamina ◽  
L.V. Kuznetsova ◽  
O.P. Budanova ◽  
E.V. Malysheva ◽  
...  
Keyword(s):  
Inflammatory Cytokines ◽  
Macrophage Phenotype ◽  
Blood Monocytes ◽  
Prostate Cells ◽  
Cultural Medium ◽  
M1 Macrophage ◽  
M1 Phenotype ◽  
Ifn Γ ◽  
Anti Inflammatory ◽  
3D Cultivation

В развитии рака предстательной железы (РПЖ) макрофаги играют важную роль. Многие опухоли выделяют противовоспалительные цитокины, которые перепрограммируют М1 фенотип макрофагов на проопухолевый М2 фенотип. М2 макрофаги подавляют противоопухолевый иммунитет, способствуют делению и метастазированию опухолевых клеток. Предыдущие исследования позволили нам обосновать предположение, что деление опухолевых клеток РПЖ человека может быть ограничено особым М3 фенотипом макрофагов. Фенотип М3, в отличие от М1 фенотипа, реагирует на противовоспалительные цитокины увеличением продукции провоспалительных противоопухолевых цитокинов, что способствует сохранению их противоопухолевых свойств в зоне опухоли. Цель исследования - проверка гипотезы о способности М3 макрофагов останавливать деление клеток предстательной железы больного РПЖ. Методика. В работе использовали макрофаги мышей, выделенные из перитонеального лаважа и макрофаги человека, полученные из моноцитов крови больных РПЖ. Фенотип М3 макрофагов получали добавлением в среду культивирования IFN-γ, ингибиторов STAT3, STAT6 и SMAD3 с последующей стимуляцией липополисахаридом. Результаты. Показано, что М3 макрофаги мышей и человека ограничивали деление клеток предстательной железы больных РПЖ в условиях 2D (на плоскости) культивирования на 43% и 93%, соответственно. При 3D (в объеме) культивировании М3 макрофаги мышей не ограничивали, а М3 макрофаги человека лишь незначительно ограничивали деление клеток предстательной железы у больных РПЖ. Заключение. Результаты работы делают обоснованными дальнейшие исследования и разработку клинической версии биотехнологии лечения рака предстательной железы с использованием М3 макрофагов.Macrophages play an important role in the development of prostate cancer (PCa). Many tumors, including PCa, secrete anti-inflammatory cytokines that reprogram the M1 macrophage phenotype into the pro-tumor M2 phenotype. M2 macrophages suppress antitumor immunity and promote division and metastasis of tumor cells. We hypothesized that the division of human PCa cells may be restricted by a specific M3 macrophage phenotype. The M3 phenotype, in contrast to the M1 phenotype, responds to anti-inflammatory cytokines by increasing the production of inflammatory anti-tumor cytokines and retains its anti-tumor properties in the tumor area. The aim of the study was to test the hypothesis on the ability of M3 macrophages to stop division of prostate cells from patients with PCa. Methods. This study used murine macrophages isolated from the peritoneal lavage and human macrophages obtained from blood monocytes of patients with PCa. The M3 macrophage phenotype was obtained by adding IFN-γ, STAT3, STAT6, and SMAD3 inhibitors to the cultural medium followed by lipopolysaccharide (LPS) stimulation. Results. Murine and human M3 macrophages restricted the division of patients’ PCa cells in the conditions of 2D cultivation by 43% and 93%, respectively. In 3D cultivation, murine M3 macrophages did not restrict whereas human M3 macrophages only slightly limited the division of prostate cells from PCa patients. The results of the study warrant further research and development of a clinical biotechnology for PCa treatment with reprogrammed M3 macrophages.

Reprogrammed M1 macrophages with inhibited STAT3, STAT6 and/or SMAD3 extends lifespan of mice with experimental carcinoma

2017 ◽  
pp. 4-9
Author(s):  
С.В. Калиш ◽  
С.В. Лямина ◽  
А.А. Раецкая ◽  
И.Ю. Малышев
Keyword(s):  
Tumor Growth ◽  
Culture Medium ◽  
Ehrlich Carcinoma ◽  
Macrophage Phenotype ◽  
M1 Macrophages ◽  
M1 Macrophage ◽  
Ec Cells ◽  
Experimental Carcinoma

Цель исследования. Репрограммирование М1 фенотипа макрофагов с ингибированными факторами транскрипции М2 фенотипа STAT3, STAТ6 и SMAD и оценка их влияния на развитие карциномы Эрлиха (КЭ) in vitro и in vivo. Методика. Рост опухоли иницировали in vitro путем добавления клеток КЭ в среду культивирования RPMI-1640 и in vivo путем внутрибрюшинной инъекции клеток КЭ мышам. Результаты. Установлено, что M1макрофаги и in vitro, и in vivo оказывают выраженный противоопухолевый эффект, который превосходит антиопухолевые эффекты М1, M1, M1 макрофагов и цисплатина. Заключение. М1 макрофаги с ингибированными STAT3, STAT6 и/или SMAD3 эффективно ограничивают рост опухоли. Полученные данные обосновывают разработку новой технологии противоопухолевой клеточной терапии. Objective. Reprogramming of M1 macrophage phenotype with inhibited M2 phenotype transcription factors, such as STAT3, STAT6 and SMAD and assess their impact on the development of Ehrlich carcinoma (EC) in vitro and in vivo . Methods. Tumor growth in vitro was initiated by addition of EC cells in RPMI-1640 culture medium and in vivo by intraperitoneal of EC cell injection into mice. Results. It was found that M1 macrophages have a pronounced anti-tumor effect in vitro , and in vivo , which was greater than anti-tumor effects of M1, M1, M1 macrophages and cisplatin. Conclusion. M1 macrophages with inhibited STAT3, STAT6 and/or SMAD3 effectively restrict tumor growth. The findings justify the development of new anti-tumor cell therapy technology.

scholarly journals Luteolin transforms the polarity of bone marrow-derived macrophages to regulate the cytokine storm

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Shuxia Wang ◽  
Shuhang Xu ◽  
Jing Zhou ◽  
Li Zhang ◽  
Xiaodong Mao ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Inflammatory Responses ◽  
Bone Marrow Cells ◽  
Membrane Surface ◽  
Inflammatory Factors ◽  
Mouse Bone Marrow ◽  
Macrophage Polarisation ◽  
Ifn Γ ◽  
Anti Inflammatory ◽  
M1 Type

Abstract Background Macrophages are indispensable regulators of inflammatory responses. Macrophage polarisation and their secreted inflammatory factors have an association with the outcome of inflammation. Luteolin, a flavonoid abundant in plants, has anti-inflammatory activity, but whether luteolin can manipulate M1/M2 polarisation of bone marrow-derived macrophages (BMDMs) to suppress inflammation is still unclear. This study aimed to observe the effects of luteolin on the polarity of BMDMs derived from C57BL/6 mice and the expression of inflammatory factors, to explore the mechanism by which luteolin regulates the BMDM polarity. Methods M1-polarised BMDMs were induced by lipopolysaccharide (LPS) + interferon (IFN)-γ and M2-polarisation were stimulated with interleukin (IL)-4. BMDM morphology and phagocytosis were observed by laser confocal microscopy; levels of BMDM differentiation and cluster of differentiation (CD)11c or CD206 on the membrane surface were assessed by flow cytometry (FCM); mRNA and protein levels of M1/M2-type inflammatory factors were performed by qPCR and ELISA, respectively; and the expression of p-STAT1 and p-STAT6 protein pathways was detected by Western-blotting. Results The isolated mouse bone marrow cells were successfully differentiated into BMDMs, LPS + IFN-γ induced BMDM M1-phenotype polarisation, and IL-4 induced M2-phenotype polarisation. After M1-polarised BMDMs were treated with luteolin, the phagocytosis of M1-polarized BMDMs was reduced, and the M1-type pro-inflammatory factors including IL-6, tumour necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS), and CD86 were downregulated while the M2-type anti-inflammatory factors including IL-10, IL-13, found in inflammatory zone (FIZZ)1, Arginase (Arg)1 and CD206 were upregulated. Additionally, the expression of M1-type surface marker CD11c decreased. Nevertheless, the M2-type marker CD206 increased; and the levels of inflammatory signalling proteins phosphorylated signal transducer and activator of transcription (p-STAT)1 and p-STAT6 were attenuated and enhanced, respectively. Conclusions Our study suggests that luteolin may transform BMDM polarity through p-STAT1/6 to regulate the expression of inflammatory mediators, thereby inhibiting inflammation. Naturally occurring luteolin holds promise as an anti-inflammatory and immunomodulatory agent.

scholarly journals Radiosensitivity index emerges as a potential biomarker for combined radiotherapy and immunotherapy

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Yang-Hong Dai ◽  
Ying-Fu Wang ◽  
Po-Chien Shen ◽  
Cheng-Hsiang Lo ◽  
Jen-Fu Yang ◽  
...  
Keyword(s):  
Dna Repair ◽  
Interferon Γ ◽  
The Cancer Genome Atlas ◽  
Differential Analysis ◽  
Macrophage Polarisation ◽  
Molecular Features ◽  
Kaplan Meier ◽  
M1 Macrophage ◽  
Potential Biomarker ◽  
Cancer Genome Atlas

AbstractIn the era of immunotherapy, there lacks of a reliable genomic predictor to identify optimal patient populations in combined radiotherapy and immunotherapy (CRI). The purpose of this study is to investigate whether genomic scores defining radiosensitivity are associated with immune response. Genomic data from Merged Microarray-Acquired dataset (MMD) were established and the Cancer Genome Atlas (TCGA) were obtained. Based on rank-based regression model including 10 genes, radiosensitivity index (RSI) was calculated. A total of 12832 primary tumours across 11 major cancer types were analysed for the association with DNA repair, cellular stemness, macrophage polarisation, and immune subtypes. Additional 585 metastatic tissues were extracted from MET500. RSI was stratified into RSI-Low and RSI-High by a cutpoint of 0.46. Proteomic differential analysis was used to identify significant proteins according to RSI categories. Gene Set Variance Analysis (GSVA) was applied to measure the genomic pathway activity (18 genes for T-cell inflamed activity). Kaplan-Meier analysis was performed for survival analysis. RSI was significantly associated with homologous DNA repair, cancer stemness and immune-related molecular features. Lower RSI was associated with higher fraction of M1 macrophage. Differential proteomic analysis identified significantly higher TAP2 expression in RSI-Low colorectal tumours. In the TCGA cohort, dominant interferon-γ (IFN-γ) response was characterised by low RSI and predicted better response to programmed cell death 1 (PD-1) blockade. In conclusion, in addition to radiation response, our study identified RSI to be associated with various immune-related features and predicted response to PD-1 blockade, thus, highlighting its potential as a candidate biomarker for CRI.

scholarly journals Role of interplay between IL-4 and IFN-γ in the in regulating M1 macrophage polarization induced by Nattectin

2012 ◽  
Vol 14 (4) ◽  
pp. 513-522 ◽  
Author(s):  
Edson Kiyotaka Ishizuka ◽  
Marcio José Ferreira ◽  
Lidiane Zito Grund ◽  
Erica Maria Martins Coutinho ◽  
Evilin Naname Komegae ◽  
...  
Keyword(s):  
Macrophage Polarization ◽  
M1 Macrophage ◽  
Ifn Γ

Abstract 116: Detrimental Role of Toll-Like Receptor 4 in Cardiovirus-Induced Myocarditis

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Fumitaka Sato ◽  
Seiichi Omura ◽  
Nicholas E Martinez ◽  
Eiichiro Kawai ◽  
Ganta V Chaitanya ◽  
...  
Keyword(s):  
Immune Responses ◽  
Acute Phase ◽  
Viral Entry ◽  
Viral Myocarditis ◽  
Chronic Phase ◽  
Enzyme Linked Immunosorbent Assay ◽  
Tlr4 Ligand ◽  
Ifn Γ ◽  
Deficient Mice

Picornavirus infections have been known as a leading cause of viral myocarditis in humans. Theiler’s murine encephalomyelitis virus (TMEV) belongs to the genus Cardiovirus, the family Picornaviridae and was reported to cause inflammation in the heart in one manuscript, while its pathomechanism is unclear. In viral myocarditis, viral replication in the heart and/or immune responses against virus as well as heart-antigen (autoimmunity) can contribute to the pathogenesis. Toll-like receptors (TLRs) are pattern recognition receptors (PRRs) that are important for recognizing pathogens as well as triggering innate immunity. Among TLRs, TLR4 has been demonstrated to play important roles in virus-mediated pathology: 1) TLR4 can contribute to viral entry in some viruses, 2) TLR4 may mediate tissue damage by anti-virus immune responses (immunopathology), 3) high levels of TLR4 expression were observed in the heart of patients with dilated cardiomyopathy following acute viral myocarditis, and 4) some viruses can bind to lipopolysaccharide (LPS), which is a TLR4 ligand. To determine the role of TLR4 in TMEV-induced myocarditis, we infected male C3H/HeJ (TLR4-deficient) and C3H/HeNtac (control TLR4+) mice with the DA strain of TMEV. We harvested the hearts and spleens on days 6 and 7 (acute phase) or days 63 and 64 (chronic phase) post-infection. Cardiac pathology was evaluated by hematoxylin and eosin staining and production of pro-inflammatory cytokines, interleukin (IL)-17A and interferon (IFN)-γ, from spleen cells was measured by an enzyme-linked immunosorbent assay (ELISA). In both mice, mild myocarditis was observed during the acute phase of TMEV infection. During the chronic phase, both mice developed severe pathology in the heart, including basophilic degeneration and calcification. However, the incidence of myocarditis was higher in control mice than TLR4-deficient mice. IL-17A and IFN-γ production was higher in control mice than in TLR4-deficient mice (control vs. TLR4-deficient mice, acute phase: IL-17A, 196 vs. 146 pg/ml; IFN-γ, 72 vs. 39 ng/ml; chronic phase: IL-17A, 290 vs. 229 pg/ml; IFN- γ, 142 vs. 88 ng/ml). These results suggest that TLR4 may be detrimental in TMEV-induced myocarditis by increasing pro-inflammatory cytokine production.

Abstract 190: Epigenetic Modifications of Pro-inflammatory Gene Expression in Macrophages by a Demethylase Enzyme, JMJD3, May Promote Chronic Inflammation in Type 2 Diabetic (T2D) Wounds

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Katherine A Gallagher ◽  
Amrita Joshi ◽  
William Carson ◽  
Dawn Coleman ◽  
Peter Henke ◽  
...  
Keyword(s):  
Gene Expression ◽  
Progenitor Cells ◽  
Chronic Inflammation ◽  
Histone Methylation ◽  
Gene Promoter ◽  
Epigenetic Modifications ◽  
Macrophage Phenotype ◽  
M1 Macrophage ◽  
Type 2 Diabetic

Introduction Type 2 diabetic(T2D) wounds are characterized by chronic inflammation, maintained by an exaggerated M1(pro-inflammatory) macrophage phenotype response. We seek to define a link between epigenetic modifications of bone marrow(BM) cells in T2D and dysregulated macrophages in wounds. We hypothesized that a chromatin modifying demethylase enzyme, JMJD3, is responsible for the decrease in H3K27me3 repressive methylation at the IL-12 gene promoter and thus drives an M1 macrophage phenotype in T2D wounds. Methods BM/adipose tissue(AT)/wounds were harvested from 30 diet-induced obese mice(DIO)(MG= 350g/DL) and 30 matched(WT) controls. For chromatin immunoprecipitation(ChIP) analysis, cells were isolated via ferromagnetic columns(CD34+,CD11b+). ChIP to detect histone methylation at the promoter regions of JMJD3 and IL-12(key M1 macrophage gene) was performed and RNA analysis was done with standard primers. Results JMJD3 mRNA in the BM is significantly increased in the DIO versus WT. ChIP showed increased H3K4me3(gene expression mark) in CD34+ progenitor cells and a corresponding decrease in H3K27me3(repressive mark) in monocytes at the promoter region of JMJD3. These changes correspond with the decrease in H3K27me3 seen at the IL-12 promoter in macrophages(CD11b+) from AT/T2D wounds. Conclusions Epigenetic changes initiated by JMJD3 in BM progenitor cells result in changes in histone methylation at the IL-12 promoter favoring an M1 phenotype in macrophages and thus contributes to the chronic inflammation seen in T2D wounds and AT. Whether manipulation of epigenetic enzymes could reduce chronic inflammation in T2D wounds requires further work.

scholarly journals The Role of Toll-Like Receptors in the Production of Cytokines by Human Lung Macrophages

2018 ◽  
Vol 12 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Stanislas Grassin-Delyle ◽  
Charlotte Abrial ◽  
Hélène Salvator ◽  
Marion Brollo ◽  
Emmanuel Naline ◽  
...  
Keyword(s):  
Human Lung ◽  
Macrophage Phenotype ◽  
Chemokine Production ◽  
Lung Macrophages ◽  
Cytokines And Chemokines ◽  
M1 Macrophage ◽  
Microbial Infections ◽  
Selective Agonists ◽  
And Function ◽  
Subtype Selective

Background: The Toll-like receptor (TLR) family is involved in the recognition of and response to microbial infections. These receptors are expressed in leukocytes. TLR stimulation induces the production of proinflammatory cytokines and chemokines. Given that human lung macrophages (LMs) constitute the first line of defense against inhaled pathogens, the objective of this study was to investigate the expression and function of TLR subtypes in this cell population. Methods: Human primary LMs were obtained from patients undergoing surgical resection. The RNA and protein expression levels of TLRs, chemokines, and cytokines were assessed after incubation with subtype-selective agonists. Results: In human LMs, the TLR expression level varied from one subtype to another. Stimulation with subtype-selective agonists induced an intense, concentration- and time-dependent increase in the production of chemokines and cytokines. TLR4 stimulation induced the strongest effect, whereas TLR9 stimulation induced a much weaker response. Conclusions: The stimulation of TLRs in human LMs induces intense cytokine and chemokine production, a characteristic of the proinflammatory M1 macrophage phenotype.

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