Metabolic characterisation of THP-1 macrophage polarisation using LC–MS-based metabolite profiling

INTRODUCTION: Macrophages constitute a heterogeneous population of functionally distinct cells involved in several physiological and pathological processes. They display remarkable plasticity by changing their phenotype and function in response to environmental cues representing a spectrum of different functional phenotypes. The so-called M1 and M2 macrophages are often considered as representative of pro- and anti-inflammatory ends of such spectrum. Metabolomics approach is a powerful tool providing important chemical information about the cellular phenotype of living systems, and the changes in their metabolic pathways in response to various perturbations. OBJECTIVES: This study aimed to characterise M1 and M2 phenotypes in THP-1 macrophagesin order to identify characteristic metabolites of each polarisation state. METHODS: Herein, untargeted liquid chromatography (LC)-mass spectrometry (MS)-based metabolite profiling was applied to characterise the metabolic profile of M1-like and M2-like THP-1 macrophages. RESULTS: The results showed that M1 and M2 macrophages have distinct metabolic profiles. Sphingolipid and pyrimidine metabolism was significantly changed in M1 macrophages whereas arginine, proline, alanine, aspartate and glutamate metabolism was significantly altered in M2 macrophages. CONCLUSION: This study represents successful application of LC-MS metabolomics approach to characterise M1 and M2 macrophages providing functional readouts that show unique metabolic signature for each phenotype. These data could contribute to a better understanding of M1 and M2 functional properties and could pave the way for developing new therapeutics targeting different immune diseases

MicroRNA-511-3p Mediated Modulation of the Peroxisome Proliferator-Activated Receptor Gamma (PPAR?) Controls LPS-Induced Inflammatory Responses in Human Monocyte Derived DCs

Abstract: The peroxisome proliferator-activated receptor gamma (PPAR) is a ligand-activated transcription factor expressed in dendritic cells (DCs), where it exerts anti-inflammatory responses against TLR4-induced inflammation. Recently, microRNA-511 (miR 511) has also emerged as a key player in controlling TLR4-mediated signalling and in regulating the function of DCs. Interestingly, PPAR has been previously highlighted as a putative target of miR-511 activity; however, the link between miR-511 and PPAR and its influence on human DC function within the context of LPS-inducedinflammatory responses is unknown. Using a selection of miR-511-3p-specific inhibitors and mimics, we demonstrate for the first time that knockdown or overexpression of miR-511-3p inversely correlates with PPAR mRNA levels and affects its transcriptional activity following treatment with rosiglitazone (RSG; PPAR agonist), in the presence or absence of LPS. Additionally, we show that PPAR-mediated suppression of DC activation and pro-inflammatory cytokine production in miR-511-3p knockdown DCs is abrogated following overexpression of miR-511-3p. Lastly, PPARactivation suppressed LPS-mediated induction of indoleamine 2,3-dioxygenase (IDO) activity in DCs, most likely due to changes in miR-511-3p expression. Our data thus suggests that PPAR-induced modulation of DC phenotype and function is influenced by miR-511 3p expression, which may serve as a potential therapeutic target against inflammatory diseases

Immune-Instructive Polymers Control Macrophage Phenotype and Modulate the Foreign Body Response In Vivo

© 2020 The Author(s) Implantation of medical devices can result in inflammation. A large library of polymers is screened, and a selection found to promote macrophage differentiation towards pro- or anti-inflammatory phenotypes. The bioinstructive properties of these materials are validated within a rodent model. By identifying novel materials with immune-instructive properties, the relationship between material-immune cell interactions could be investigated, and this offers exciting possibilities to design novel bioinstructive materials that can be used for numerous clinical applications including medical implants

Innate immune cell instruction using micron-scale 3D objects of varied architecture and polymer chemistry: The ChemoArchiChip

To design effective immunomodulatory implants, innate immune cell interactions at the surface of biomaterials need to be controlled and understood. The architectural design freedom of two-photon polymerization is used to produce arrays of surface-mounted, geometrically diverse 3D polymer objects. This reveals the importance of the interplay between architecture and materials chemistry in determining human macrophage fate in vitro. The ChemoArchiChip identifies key structure-function relationships and design rules from machine learning models to build a mechanistic understanding of cell attachment and polarization. Object shape, vertex/cone angle, and size are key drivers of attachment. Particular shapes are found to heavily modulate pro- or anti-inflammatory cell polarization, while triangular pyramids drastically reduce or even eliminate attachment. Caveola-dependent endocytosis is a principal mechanism by which cells respond to objects with sharp points; i.e., low vertex/cone angles. The discovery of these putative design rules points to surfaces decorated with architectures to augment implant performance