Dataset Information

TLR7 activation in M-CSF-dependent monocyte-derived human macrophages potentiates inflammatory responses and prompts neutrophil recruitment.

ABSTRACT: Toll-like receptor 7 (TLR7) is an endosomal Pathogen-Associated Molecular Pattern (PAMP) receptor that senses single-stranded RNA (ssRNA) and whose engagement results in the production of type I IFN and pro-inflammatory cytokines upon viral exposure. Recent genetic studies have established that a dysfunctional TLR7-initiated signaling is directly linked to the development of inflammatory responses. We present evidences that TLR7 is preferentially expressed by monocyte-derived macrophages generated in the presence of M-CSF (M-MØ). We now show that TLR7 activation in M-MØ triggers a weak MAPK, NFκB and STAT1 activation and results in low production of type I IFN. Of note, TLR7 engagement re-programs MAFB+ M-MØ towards a pro-inflammatory transcriptional profile characterized by the expression of neutrophil-attracting chemokines (CXCL1-3, CXCL5, CXCL8), whose expression is dependent on the transcription factors MAFB and AhR. Moreover, TLR7-activated M-MØ display enhanced pro-inflammatory responses and a stronger production of neutrophil-attracting chemokines upon secondary stimulation. As aberrant TLR7 signaling and enhanced pulmonary neutrophil/lymphocyte ratio associate with impaired resolution of virus-induced inflammatory responses, these results suggest that targeting macrophage TLR7 might be a therapeutic strategy for viral infections where monocyte-derived macrophages exhibit a pathogenic role.

SUBMITTER: Simon-Fuentes M

PROVIDER: S-EPMC10315069 | biostudies-literature | 2023 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

TLR7 Activation in M-CSF-Dependent Monocyte-Derived Human Macrophages Potentiates Inflammatory Responses and Prompts Neutrophil Recruitment.

Simón-Fuentes Miriam M Herrero Cristina C Acero-Riaguas Lucia L Nieto Concha C Lasala Fatima F Labiod Nuria N Luczkowiak Joanna J Alonso Bárbara B Delgado Rafael R Colmenares Maria M Corbí Ángel L ÁL Domínguez-Soto Ángeles Á

Journal of innate immunity 20230411 1

Toll-like receptor 7 (TLR7) is an endosomal pathogen-associated molecular pattern (PAMP) receptor that senses single-stranded RNA (ssRNA) and whose engagement results in the production of type I IFN and pro-inflammatory cytokines upon viral exposure. Recent genetic studies have established that a dysfunctional TLR7-initiated signaling is directly linked to the development of inflammatory responses. We present evidence that TLR7 is preferentially expressed by monocyte-derived macrophages generate ...[more]

PMID: 37040733

Similar Datasets

Project description:Necrotizing enterocolitis (NEC) is a life-threatening, inflammatory disease affecting premature infants with intestinal necrosis, but the mechanism remains unclear. Neonatal macrophages are thought to play an important role in the pathogenesis of NEC through the production of proinflammatory cytokines. Restriction of cytokine expression in macrophages of NEC tissues may be beneficial. In adult macrophages, interfering with Rac1 has been shown to influence the expression of cytokines. Here, we investigated whether interfering with Rac1 in neonatal macrophages affects their inflammatory responses. First, we found that Rac1-activation was upregulated in the macrophages of rats with NEC model induction compared to controls. The M1 macrophages derived from human neonatal monocytes showed greater Rac1-activation than the M2 macrophages derived from the same monocytes. Inhibition of Rac1-activation by NSC23766 potently reduced the production of proinflammatory cytokines in these M1 macrophages. While neonatal monocytes differentiated into M1 macrophages in vitro, NSC23766 significantly altered cell function during the first six days of incubation with GM-CSF rather than during the subsequent stimulation phase. However, the same effect of NSC23766 was not observed in adult macrophages. Using mass spectrometry, Y-box binding protein 1 (YB1) was identified as being downregulated upon inhibition of Rac1-activation in the neonatal macrophages. Moreover, we found that inhibition of Rac1-activation shortens the poly A tail of PABPC1 mRNA, thereby reducing the translation of PABPC1 mRNA. Consequently, the downregulation of PABPC1 resulted in a reduced translation of YB1 mRNA. Furthermore, we found that TLR4 expression was downregulated in neonatal macrophages, while YB1 expression was reduced. Adding resatorvid (TLR4 signaling inhibitor) to the macrophages treated with NSC23766 did not further reduce the cytokine expression. These findings reveal a novel Rac1-mediated pathway to inhibit cytokine expression in neonatal M1 macrophages and suggest potential targets for the prevention or treatment of NEC.

Project description:The immune response to Mycobacterium tuberculosis infection determines tuberculosis disease outcomes, yet we have an incomplete understanding of what immune factors contribute to a protective immune response. Neutrophilic inflammation has been associated with poor disease prognosis in humans and in animal models during M. tuberculosis infection and, therefore, must be tightly regulated. ATG5 is an essential autophagy protein that is required in innate immune cells to control neutrophil-dominated inflammation and promote survival during M. tuberculosis infection; however, the mechanistic basis for how ATG5 regulates neutrophil recruitment is unknown. To interrogate what innate immune cells require ATG5 to control neutrophil recruitment during M. tuberculosis infection, we used different mouse strains that conditionally delete Atg5 in specific cell types. We found that ATG5 is required in CD11c+ cells (lung macrophages and dendritic cells) to control the production of proinflammatory cytokines and chemokines during M. tuberculosis infection, which would otherwise promote neutrophil recruitment. This role for ATG5 is autophagy dependent, but independent of mitophagy, LC3-associated phagocytosis, and inflammasome activation, which are the most well-characterized ways that autophagy proteins regulate inflammation. In addition to the increased proinflammatory cytokine production from macrophages during M. tuberculosis infection, loss of ATG5 in innate immune cells also results in an early induction of TH17 responses. Despite prior published in vitro cell culture experiments supporting a role for autophagy in controlling M. tuberculosis replication in macrophages, the effects of autophagy on inflammatory responses occur without changes in M. tuberculosis burden in macrophages. These findings reveal new roles for autophagy proteins in lung resident macrophages and dendritic cells that are required to suppress inflammatory responses that are associated with poor control of M. tuberculosis infection.

Dataset Information

TLR7 activation in M-CSF-dependent monocyte-derived human macrophages potentiates inflammatory responses and prompts neutrophil recruitment.

Publications

TLR7 Activation in M-CSF-Dependent Monocyte-Derived Human Macrophages Potentiates Inflammatory Responses and Prompts Neutrophil Recruitment.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets