Macrophage ATF6 Accelerates Orthodontic Tooth Movement through Promoting Tnfα Transcription
Ontology highlight
ABSTRACT: Corticotomy is a clinical procedure targeting alveolar bone to activate regional acceleratory phenomenon (RAP) and promote orthodontic tooth movement (OTM). Corticotomy involves the orchestration of inflammation by macrophages, but the underlying mechanism remains unclear. Here, we identify endoplasmic reticulum (ER) stress sensor activating transcription factor 6 (ATF6) as a critical player modulating pro- and anti-inflammatory macrophage polarization. We show that macrophage-specific ATF6 deletion blocks corticotomy-induced OTM acceleration, while macrophage ATF6 overexpression exaggerates the acceleration effect. Furthermore, the proportion of pro-inflammatory macrophages is positively correlated with ATF6 expression in vitro and in vivo. By RNA-seq and CUT&Tag, we demonstrate that ATF6 interacts with Tnfα promotor and augments its transcription, thereby mediating the effect of TNF signaling pathway in pro-inflammatory macrophage polarization. In summary, ATF6 may aggravate alveolar bone remodeling during corticotomy by promoting Tnfα transcription in macrophages, suggesting that ATF6 may represent a promising therapeutic target for non-invasive accelerating orthodontics.
Project description:Corticotomy is a clinical procedure targeting alveolar bone to activate regional acceleratory phenomenon (RAP) and promote orthodontic tooth movement (OTM). Corticotomy involves the orchestration of inflammation by macrophages, but the underlying mechanism remains unclear. Here, we identify endoplasmic reticulum (ER) stress sensor activating transcription factor 6 (ATF6) as a critical player modulating pro- and anti-inflammatory macrophage polarization. We show that macrophage-specific ATF6 deletion blocks corticotomy-induced OTM acceleration, while macrophage ATF6 overexpression exaggerates the acceleration effect. Furthermore, the proportion of pro-inflammatory macrophages is positively correlated with ATF6 expression in vitro and in vivo. By RNA-seq and CUT&Tag, we demonstrate that ATF6 interacts with Tnfα promotor and augments its transcription, thereby mediating the effect of TNF signaling pathway in pro-inflammatory macrophage polarization. In summary, ATF6 may aggravate alveolar bone remodeling during corticotomy by promoting Tnfα transcription in macrophages, suggesting that ATF6 may represent a promising therapeutic target for non-invasive accelerating orthodontics.
Project description:<p>Macrophages are prominent immune cells in the tumor microenvironment that can be educated into pro-tumoral phenotype by tumor cells to favor tumor growth and metastasis. The mechanisms that mediate a mutualistic relationship between tumor cells and macrophages remain poorly characterized. Here, we have shown <em>in vitro</em> that different human and murine cancer cell lines release branched‐chain α‐ketoacids (BCKAs) into the extracellular milieu, which influence macrophage polarization in an monocarboxylate transporter 1 (MCT1)‐dependent manner. We found that α‐ketoisocaproate (KIC) and α‐keto‐β‐methylvalerate (KMV) induced a pro‐tumoral macrophage state, whereas α‐ketoisovalerate (KIV) exerted a pro‐inflammatory effect on macrophages. This process was further investigated by a combined metabolomics/proteomics platform. KMV and KIC altered macrophage tricarboxylic acid (TCA) cycle intermediates and increased polyamine metabolism. Proteomic and pathway analyses revealed that the three BCKAs, especially KMV, exhibited divergent effects on the inflammatory signal pathways, phagocytosis, apoptosis and redox balance. These findings uncover cancer‐derived BCKAs as novel determinants for macrophage polarization with potential to be selectively exploited for optimizing antitumor immune responses.</p>
Project description:Macrophage activation is associated with profound transcriptional reprogramming. Although much progress has been made in the understanding of macrophage activation, polarization and function, the transcriptional programs regulating these processes remain poorly characterized. We stimulated human macrophages with diverse activation signals, acquiring a dataset of 299 macrophage transcriptomes. Analysis of this dataset revealed a spectrum of macrophage activation states extending the current M1 versus M2-polarization model. Network analyses identified central transcriptional regulators associated with all macrophage activation complemented by regulators related to stimulus-specific programs. Applying these transcriptional programs to human alveolar macrophages from smokers and patients with chronic obstructive pulmonary disease (COPD) revealed an unexpected loss of inflammatory signatures in COPD patients. Finally, by integrating murine data from the ImmGen project we propose a refined, activation-independent core signature for human and murine macrophages. This resource serves as a framework for future research into regulation of macrophage activation in health and disease. Since transcriptional programs are further modulated on several levels including miRNAs we assessed the global spectrum of miRNA expression by miRNA-Seq in macrophages stimulated with IFNM-NM-3, IL4 or with the combination of TNFM-NM-1, PGE2 and P3C
Project description:Macrophage activation is associated with profound transcriptional reprogramming. Although much progress has been made in the understanding of macrophage activation, polarization and function, the transcriptional programs regulating these processes remain poorly characterized. We stimulated human macrophages with diverse activation signals, acquiring a dataset of 299 macrophage transcriptomes. Analysis of this dataset revealed a spectrum of macrophage activation states extending the current M1 versus M2-polarization model. Network analyses identified central transcriptional regulators associated with all macrophage activation complemented by regulators related to stimulus-specific programs. Applying these transcriptional programs to human alveolar macrophages from smokers and patients with chronic obstructive pulmonary disease (COPD) revealed an unexpected loss of inflammatory signatures in COPD patients. Finally, by integrating murine data from the ImmGen project we propose a refined, activation-independent core signature for human and murine macrophages. This resource serves as a framework for future research into regulation of macrophage activation in health and disease. To better understand active gene regulation in human macrophages during activation and differentiation in vitro with different stimuli ChIP-sequencing experiments were performed. Enrichment patterns of the permissive histone modification mark trimetylation of histone protein 3 (H3K4me3) and macrophage lineage-specific transcription factor PU.1 were analyzed.
Project description:A purified spike (S) glycoprotein for SARS-COV-2 coronavirus was used to studying its effects on THP-1 macrophages, PBMCs and HUVEC cells. The S protein mediates SARS-CoV-2 entry into cells through binding to angiotensin converting enzyme 2 (ACE2) receptors. We measured viability, intracellular cytokines release, oxidative stress, pro-inflammatory markers and THP-1-like macrophage polarization. We identified an increase in apoptosis, ROS generation, MCP-1 and intracellular calcium expression in THP-1 macrophages. Furthermore, stimulation with the S protein polarizes THP-1 macrophages towards pro-inflammatory futures with an increase in TNFα and MHC-II M1-like phenotype markers. Treatment of cells with an ACE inhibitor, perindopril at 100nM reduced apoptosis, ROS and MHC-II expression. We further analyzed the sensitivity of HUVEC cells after exposure to a conditioned media (CM) of THP-1 macrophages stimulated with S protein. CM induced endothelial cell apoptosis and MCP-1 expression. Treatment with perindopril reduced these effects. However, direct stimulation of HUVEC cells with S protein slightly increased HIF1α and MCP-1 expression which was significantly exaggerated by ACE inhibitor treatment. S protein stimulation induced ROS generation and changed mitogenic responses of PBMCs through upregulation of TNFα and IL-17 cytokine expressions. These effects were blunted by perindopril (100nM) treatment. Proteomic analysis of S protein stimulated THP-1 macrophages with or without perindopril (100nM) uncovered more than 400 differentially regulated proteins. Our results provide a mechanistic analysis suggesting that blood and vascular component could be activated directly through S protein systemically present in circulation and that activation of local renin angiotensin system might be partially involved in this process.
Project description:Background: Periodontitis is a chronic inflammatory disease and macrophages play a pivotal role in the progression of periodontitis. Mesenchymal stem cells (MSCs) have emerged as potential therapeutic agents for the treatment of periodontitis due to their immunomodulatory properties and capacity for tissue regeneration. Compared to conventionally derived MSCs, induced pluripotent stem cell-derived MSCs (iMSCs) offer distinct advantages as promising candidates for MSC-based therapies, owing to their non-invasive acquisition methods and virtually unlimited availability. This study aims to investigate the effects and mechanisms of iMSCs in modulating macrophage polarization and alleviating periodontitis-related alveolar bone loss. Methods: iMSCs were generated from iPSCs and characterized for differentiation potential. The effects of iMSCs on macrophage polarization were evaluated using THP-1-derived macrophages under inflammatory conditions (LPS and IFN-γ stimulation). Co-culture assays, cytokine analysis, reactive oxygen species (ROS) detection, transcriptomic analysis, flow cytometry, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and western blot analysis were performed to elucidate the underlying mechanisms. The therapeutic potential of iMSCs was assessed in a ligature-induced periodontitis mouse model using micro-CT, histological analysis, and immunofluorescence staining. Results: iMSCs inhibit M1 macrophage polarization through the suppression of the NF-κB signaling pathway. Additionally, iMSCs reduce the production of pro-inflammatory cytokines (IL-1β, IL-17) and reactive oxygen species (ROS), while enhancing the secretion of anti-inflammatory cytokines (IL-10) and growth factors (VEGF), thereby improving the inflammatory microenvironment. Under inflammatory conditions, iMSCs preserve the osteogenic potential of periodontal ligament stem cells (PDLSCs) and alleviate alveolar bone loss in mice with periodontitis. In vivo, iMSCs reduce the number of M1 macrophages and inhibit the activation of NF-κB in periodontal tissues, supporting their anti-inflammatory and immunomodulatory effects. Conclusion: iMSCs demonstrate significant therapeutic potential in periodontitis by modulating macrophage polarization, reducing oxidative stress, and mitigating alveolar bone loss associated with the disease. These findings provide new insights into the mechanisms of iMSCs and their application as cell-based therapies for periodontal diseases.
Project description:Macrophage activation syndrome (MAS) is a life-threatening complication of systemic juvenile idiopathic arthritis (SJIA), and increasingly reported in association with severe lung disease (SJIA-LD) of unknown etiology. This study mechanistically defines the novel observation of pulmonary inflammation in the TLR9 mouse model of MAS that recapitulate key features of SJIA-LD, including IFNg activation. In acute MAS, lungs exhibit a mild but diffuse lymphocyte-predominant perivascular, interstitial inflammation with elevated IFNg, IFN-induced chemokines, and alveolar macrophage (AMf) expression of IFNg-induced genes. However, MAS resolution demonstrated AMf expansion and increased interstitial inflammation. AMf microarrays confirmed IFNg-induced proinflammatory polarization during acute MAS, which switches towards anti-inflammatory phenotype during MAS resolution. Interestingly, recurrent MAS increased alveolar inflammation, and reset polarization towards a pro-inflammatory state. Furthermore, in mice bearing macrophages insensitive to IFNg, both systemic feature of MAS and pulmonary inflammation were markedly attenuated. These findings demonstrate experimental MAS induces IFNg-driven pulmonary inflammation, and define this system for further study of and treatment validation in SJIA-LD. We used microarrays to study whole transcriptome analysis of alveolar macrophages in the TLR9 mouse model of MAS during both acute MAS and MAS resolution.
Project description:Macrophages are essential cells of the immune system that alter their inflammatory profile depending on their microenvironment. Alternative polyadenylation in the 3'UTR (3'UTR-APA) and intronic polyadenylation (IPA) are mechanisms that modulate gene expression, in particular in cancer and activated immune cells. Yet, how polarization and colorectal cancer (CRC) cells microenvironment affect 3'UTR-APA and IPA in primary human macrophages remains unknown. Here, primary human monocytes were isolated from healthy donors, differentiated and polarized into a pro-inflammatory state and ChrRNA-Seq and 3'RNA-Seq were performed to quantify gene expression and characterize new 3’UTR-APA and IPA mRNA isoforms. Our results show that polarization of human macrophages from naïve to a pro-inflammatory state causes a marked increase both in proximal polyA site selection in the 3'UTR and in IPA events, in genes relevant for macrophage functions. Additionally, we found a negative correlation between differential gene expression and IPA during pro-inflammatory polarization of primary human macrophages. As macrophages are abundant immune cells in the CRC microenvironment that either promote or abrogate cancer progression, we investigated how indirect exposure to CRC cells affects macrophage gene expression and 3'UTR-APA and IPA mRNA events. Co-culture with CRC cells alters the inflammatory phenotype of macrophages, increases the expression of pro-tumoral genes and induce 3’UTR-APA alterations. Notably, some of these gene expression differences were also found in tumour-associated macrophages of CRC patients, indicating that they are physiological relevant. Upon macrophage pro-inflammatory polarization SRSF12 is the pre-mRNA processing gene that is most upregulated. After SRSF12 knockdown in M1 macrophages there is a global downregulation of gene expression, in particular in genes involved in gene expression regulation and in immune responses. Our results reveal new 3’UTR-APA and IPA mRNA isoforms produced during pro-inflammatory polarization of primary human macrophages and CRC co-culture that may be used in the future as diagnostic or therapeutic tools.
Project description:Studies in various animal models suggest an important role for pulmonary macrophages in the pathogenesis of pulmonary hypertension (PH). Yet, the molecular mechanisms characterizing the functional macrophage phenotype relative to time and pulmonary localization/compartmentalization remain largely unknown. Here, we utilized a hypoxic murine model of PH in combination with flow cytometry assisted cell sorting (FACS) to quantify and isolate lung macrophages from two compartments over time and characterized their programing via RNA sequencing (RNAseq) approaches. In response to hypoxia, we found an early increase in macrophage number that was restricted to the interstitial/perivascular compartment, without recruitment of macrophages to the alveolar compartment or changes in the number of resident alveolar macrophages. Principle component analysis demonstrated significant differences in overall gene expression between alveolar (AMs) and interstitial macrophages (IMs) at baseline and after 4 and 14 days hypoxic exposure. AM’s at both day 4 and 14 and IM’s at day 4 shared a conserved “hypoxia program” characterized by mitochondrial dysfunction, pro-inflammatory gene activation and mTORC1 signaling, while IM’s at day 14 demonstrated a unique anti-inflammatory/ pro-reparative programming state. We conclude that the pathogenesis of vascular remodeling in hypoxic PH involves an early compartment independent activation of lung macrophages towards a conserved hypoxia program, with the development of compartment specific programs later on in the course of disease. Thus, harnessing time and compartment specific differences in lung macrophage polarization needs to be considered in the therapeutic targeting of macrophages in hypoxic PH and potentially other inflammatory lung diseases.
Project description:Immune responses are crucial to maintaining tissue homeostasis upon tissue injury. Upon various types of challenges, macrophages play a central role in regulating inflammation and tissue repair processes. While an immunomodulatory role of Wnt antagonist Dickkopf1 (DKK1) has been implicated, the role of Wnt antagonist DKK1 in regulating macrophage polarization in inflammation and the tissue repair process remains elusive. Here we found that DKK1 induces differential gene expression profiles from type 2-cytokine-activated macrophages to promote inflammation and tissue repair. Importantly, DKK1 induced pro-inflammatory and pro-resolving gene expressions via JNK (c-jun N-terminal kinase) in macrophages. Furthermore, DKK1 potentiated IL-13-mediated macrophage polarization and activation. Co-inhibition of JNK and STAT6 markedly decreased pro-inflammatory and pro-resolving gene expressions by DKK1 and IL-13. Interestingly, thrombocyte-specific deletion of DKK1 in mice reduced monocyte-derived macrophages in the acute sterile bleomycin (BLM)-induced lung injury model, suggesting that thrombocytes communicate with macrophages via DKK1 to orchestrate inflammation-induced injury repair process. Taken together, our study demonstrates DKK1’s role as a key regulatory role in macrophage polarization in the injury-induced inflammation and repair process.