Project description:Systematic analyses of the temporal dynamics of transcriptomes and chromatin landscapes of macrophages during timecourse of TLR4-mediated inflammatory response. As a multifunctional effector cell, macrophages play pivotal roles in both the induction and resolution components of varied inflammatory processes. During the course of an inflammation response, macrophages engage in a homeostatic program characterized by tightly coordinated modulation of temporal outputs of both lipid metabolism and inflammation. We demonstrate inversely biphasic temporal dynamics of specific fatty acid metabolic and inflammatory gene expression profiles, associated with concordant temporal reprogramming of macrophage fatty acid profiles. In part, the late phase of the macrophage inflammatory response is characterized by tailoring of fatty acid related gene expressions, facilitating both significant induction of anti-inflammatory unsaturated fatty acid production and associated resolution of inflammation. We demonstrate the biphasic temporal dynamics of macrophage inflammation, specifically anti-inflammatory omega-3 and omega-9 unsaturated fatty acid levels, are transcriptionally driven genome-wide by an unexpected shift from an LXR to SREBP1-dominant regulatory program in the late phase inflammatory response. Collectively, our findings reveal a novel Srebp1-driven mechanism allowing the intimate inverse temporal relationship between the transcriptional regulation of inflammatory and fatty acid metabolic outputs; whereby modulation key transcriptional regulators (LXR, SREBP1 and NF-kB) of these pathways coordinate appropriate temporal tailoring of local enhancer associated reprogramming and eventual pathway regulatory interactions, during the course of TLR4-dependent inflammatory response in macrophages. This specific Srebp-driven, temporal reprogramming of macrophage fatty acid metabolism, characterized by late phase induction of anti-inflammatory unsaturated fatty acid production, is necessary for appropriate resolution of inflammation. Thus, this study suggests that selective reprogramming of macrophage lipid metabolism can serve as a viable therapeutic intervention aimed at ameliorating chronic inflammation and varied metabolic syndrome associated states.
Project description:Mendelian diseases that present with immune-mediated disorders can provide insights into the molecular mechanisms that drive inflammation. Hermansky-Pudlak syndrome (HPS) types 1 and 4 are caused by defective vesicle trafficking involving the BLOC-3 complex. The presence of inflammatory complications such as Crohn’s disease-like inflammation and lung fibrosis in these patients remains enigmatic. Using mass cytometry we observe an augmented inflammatory monocyte compartment in HPS1 patient peripheral blood that may be associated with a TNF - and IL-1α-dominated cytokine dysregulation. HPS1 patient monocyte-derived macrophages express an inflammatory TNF-OSM mRNA gene signature and changes in lipid metabolism. Using stimulation experiments and lysosomal proteomics we show that defective lipid metabolism drives RAB32-dependent mTOR signaling, facilitated by the accumulation of mTOR on lysosomes. This pathogenic circuit translates into aberrant bacterial clearance, which can be rescued with mTORC1 inhibition. We reveal that a pathogenic lipid-mTOR signaling circuit acts as a metabolic checkpoint for defective anti-microbial activity. This mechanism may be relevant to the complex pathology of HPS1 patients featuring macrophage lipid accumulation, granuloma formation, defective anti-microbial activity and tissue inflammation. Lastly, this circuit may be present in a wider group of disorders with defective lipid metabolism and cholesterol accumulation.
Project description:Mendelian diseases that present with immune-mediated disorders can provide insights into the molecular mechanisms that drive inflammation. Hermansky-Pudlak syndrome (HPS) types 1 and 4 are caused by defective vesicle trafficking involving the BLOC-3 complex. The presence of inflammatory complications such as Crohn’s disease-like inflammation and lung fibrosis in these patients remains enigmatic. Using mass cytometry we observe an augmented inflammatory monocyte compartment in HPS1 patient peripheral blood that may be associated with a TNF - and IL-1α-dominated cytokine dysregulation. HPS1 patient monocyte-derived macrophages express an inflammatory TNF-OSM mRNA gene signature and changes in lipid metabolism. Using stimulation experiments and lysosomal proteomics we show that defective lipid metabolism drives RAB32-dependent mTOR signaling, facilitated by the accumulation of mTOR on lysosomes. This pathogenic circuit translates into aberrant bacterial clearance, which can be rescued with mTORC1 inhibition. We reveal that a pathogenic lipid-mTOR signaling circuit acts as a metabolic checkpoint for defective anti-microbial activity. This mechanism may be relevant to the complex pathology of HPS1 patients featuring macrophage lipid accumulation, granuloma formation, defective anti-microbial activity and tissue inflammation. Lastly, this circuit may be present in a wider group of disorders with defective lipid metabolism and cholesterol accumulation.
Project description:Dunster2014 - WBC Interactions (Model1)
This is a sub-model of a three-step
inflammatory response modelling study. The model includes distinct
populations of white blood cells namely, macrophages and active and
apoptotic neutrophil populations. Neutrophil apoptosis rate is
predicted to be crucial for the qualitative nature of the
system.
This model is described in the article:
The resolution of
inflammation: a mathematical model of neutrophil and macrophage
interactions.
Dunster JL, Byrne HM, King JR.
Bull. Math. Biol. 2014 Aug; 76(8):
1953-1980
Abstract:
There is growing interest in inflammation due to its
involvement in many diverse medical conditions, including
Alzheimer's disease, cancer, arthritis and asthma. The
traditional view that resolution of inflammation is a passive
process is now being superceded by an alternative hypothesis
whereby its resolution is an active, anti-inflammatory process
that can be manipulated therapeutically. This shift in mindset
has stimulated a resurgence of interest in the biological
mechanisms by which inflammation resolves. The
anti-inflammatory processes central to the resolution of
inflammation revolve around macrophages and are closely related
to pro-inflammatory processes mediated by neutrophils and their
ability to damage healthy tissue. We develop a spatially
averaged model of inflammation centring on its resolution,
accounting for populations of neutrophils and macrophages and
incorporating both pro- and anti-inflammatory processes. Our
ordinary differential equation model exhibits two outcomes that
we relate to healthy and unhealthy states. We use bifurcation
analysis to investigate how variation in the system parameters
affects its outcome. We find that therapeutic manipulation of
the rate of macrophage phagocytosis can aid in resolving
inflammation but success is critically dependent on the rate of
neutrophil apoptosis. Indeed our model predicts that an
effective treatment protocol would take a dual approach,
targeting macrophage phagocytosis alongside neutrophil
apoptosis.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000616.
To cite BioModels Database, please use:
BioModels Database:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
Project description:Chronic inflammation underpins many human diseases. The morbidity and mortality of chronic inflammation is often mediated through metabolic dysfunction. Inflammatory and metabolic processes vary through circadian time, suggesting an important temporal crosstalk between these systems. Using an established mouse model of rheumatoid arthritis, here we show thatchronic inflammatory arthritis results in rhythmic joint inflammation and drives major changes in muscle and liver energy metabolism and rhythmic gene expression. Transcriptional and phosphoproteomic analyses reveal alteration in lipid metabolism and mitochondrial function associated with increased EGFR-JAK11 STAT3 signalling. Metabolomic analyses confirmed rhythmic metabolic rewiring with impaired β-oxidation and lipid handling, and revealed a pronounced shunt towards sphingolipid and ceramide accumulation. The arthritis-related production of ceramides was most pronounced during the day, the time of peak inflammation and increased reliance on fatty acid oxidation. Thus, our data demonstrate that localised joint inflammation drives a time-of-day dependent build-up of bioactive lipid species driven by rhythmic inflammation and altered EGFR-STAT signalling.
Project description:Interferon regulatory factor (IRF) 5 has a major role in defining inflammatory macrophage polarization, but the molecular mechanisms of its function as a transcriptional regulator of inflammatory genes are not fully understood. Here, we characterise the sites of IRF5 recruitment in inflammatory macrophages in response to LPS.
Project description:Interferon regulatory factor (IRF) 5 has a major role in defining inflammatory macrophage polarization, but the molecular mechanisms of its function as a transcriptional regulator of inflammatory genes are not fully understood. Here, we characterise the sites of IRF5 recruitment in inflammatory macrophages in response to LPS.
Project description:The model is the second model of the publication "Modeling the role of lanthionine synthetase C-like 2 (LANCL2) in the modulation of immune responses to Helicobacter pylori infection" published in PlosOne by Leber, Bassaganya-Riera, Tubau-Juni, Zoccoli-Rodriguez, Viladomiu, Abedi, Lu, and Hontecillas.
Abstract:
Immune responses to Helicobacter pylori are orchestrated through complex balances of host-bacterial interactions, including inflammatory and regulatory immune responses across scales that can lead to the development of the gastric disease or the promotion of beneficial systemic effects. While inflammation in response to the bacterium has been reasonably characterized, the regulatory pathways that contribute to preventing inflammatory events during H. pylori infection are incompletely understood. To aid in this effort, we have generated a computational model incorporating recent developments in the understanding of H. pylori-host interactions. Sensitivity analysis of this model reveals that a regulatory macrophage population is critical in maintaining high H. pylori colonization without the generation of an inflammatory response. To address how this myeloid cell subset arises, we developed a second model describing an intracellular signaling network for the differentiation of macrophages. Modeling studies predicted that LANCL2 is a central regulator of inflammatory and effector pathways and its activation promotes regulatory responses characterized by IL-10 production while suppressing effector responses. The predicted impairment of regulatory macrophage differentiation by the loss of LANCL2 was simulated based on multiscale linkages between the tissue-level gastric mucosa and the intracellular models. The simulated deletion of LANCL2 resulted in a greater clearance of H. pylori, but also greater IFNγ responses and damage to the epithelium. The model predictions were validated within a mouse model of H. pylori colonization in wild-type (WT), LANCL2 whole body KO and myeloid-specific LANCL2-/- (LANCL2Myeloid) mice, which displayed similar decreases in H. pylori burden, CX3CR1+ IL-10-producing macrophages, and type 1 regulatory (Tr1) T cells. This study shows the importance of LANCL2 in the induction of regulatory responses in macrophages and T cells during H. pylori infection.
Project description:The model is first model of tissue level cellular immune responses to H. pylori in the publication, "Modeling the role of lanthionine synthetase C-like 2 (LANCL2) in the modulation of immune responses to Helicobacter pylori infection" in PlosOne by Leber, Bassaganya-Riera, Tubau-Juni, Zoccoli-Rodriguez, Viladomiu, Abedi, Lu, and Hontecillas.
Abstract:
Immune responses to Helicobacter pylori are orchestrated through complex balances of host-bacterial interactions, including inflammatory and regulatory immune responses across scales that can lead to the development of the gastric disease or the promotion of beneficial systemic effects. While inflammation in response to the bacterium has been reasonably characterized, the regulatory pathways that contribute to preventing inflammatory events during H. pylori infection are incompletely understood. To aid in this effort, we have generated a computational model incorporating recent developments in the understanding of H. pylori-host interactions. Sensitivity analysis of this model reveals that a regulatory macrophage population is critical in maintaining high H. pylori colonization without the generation of an inflammatory response. To address how this myeloid cell subset arises, we developed a second model describing an intracellular signaling network for the differentiation of macrophages. Modeling studies predicted that LANCL2 is a central regulator of inflammatory and effector pathways and its activation promotes regulatory responses characterized by IL-10 production while suppressing effector responses. The predicted impairment of regulatory macrophage differentiation by the loss of LANCL2 was simulated based on multiscale linkages between the tissue-level gastric mucosa and the intracellular models. The simulated deletion of LANCL2 resulted in a greater clearance of H. pylori, but also greater IFNγ responses and damage to the epithelium. The model predictions were validated within a mouse model of H. pylori colonization in wild-type (WT), LANCL2 whole body KO and myeloid-specific LANCL2-/- (LANCL2Myeloid) mice, which displayed similar decreases in H. pylori burden, CX3CR1+ IL-10-producing macrophages, and type 1 regulatory (Tr1) T cells. This study shows the importance of LANCL2 in the induction of regulatory responses in macrophages and T cells during H. pylori infection.