RESUMO
T helper 9 (TH9) cells promote allergic tissue inflammation and express the type 2 cytokines, IL-9 and IL-13, as well as the transcription factor, PPAR-γ. However, the functional role of PPAR-γ in human TH9 cells remains unknown. Here, we demonstrate that PPAR-γ drives activation-induced glycolysis, which, in turn, promotes the expression of IL-9, but not IL-13, in an mTORC1-dependent manner. In vitro and ex vivo experiments show that the PPAR-γ-mTORC1-IL-9 pathway is active in TH9 cells in human skin inflammation. Additionally, we find dynamic regulation of tissue glucose levels in acute allergic skin inflammation, suggesting that in situ glucose availability is linked to distinct immunological functions in vivo. Furthermore, paracrine IL-9 induces expression of the lactate transporter, MCT1, in TH cells and promotes their aerobic glycolysis and proliferative capacity. Altogether, our findings uncover a hitherto unknown relationship between PPAR-γ-dependent glucose metabolism and pathogenic effector functions in human TH9 cells.
Assuntos
Interleucina-9 , PPAR gama , Humanos , Glucose/metabolismo , Glicólise , Inflamação/patologia , Interleucina-13/metabolismo , PPAR gama/genética , PPAR gama/metabolismo , Linfócitos T Auxiliares-IndutoresRESUMO
Although TH1, TH2, and TH17 cells are well-defined TH cell lineages in humans, it remains debated whether IL-9-producing TH cells represent a bona fide "TH9" lineage. Our understanding of the cellular characteristics and functions of IL-9-producing TH cells in humans is still nascent. Here, we report that human IL-9-producing TH cells express the chemokine receptors CCR4 and CCR8, produce high levels of IL-5 and IL-13, and express TH2 lineage-associated transcription factors. In these cells, IL-9 production is activation dependent, transient, and accompanied by down-regulation of TH2 cytokines, leading to an apparent "TH9" phenotype. IL-9+ TH2 cells can be distinguished from "conventional" TH2 cells based on their expression of the transcription factor PPAR-γ. Accordingly, PPAR-γ is induced in naïve TH cells by priming with IL-4 and TGF-ß ("TH9" priming) and is required for IL-9 production. In line with their identity as early activated TH2 cells, IL-9+ TH2 cells are found in acute allergic skin inflammation in humans. We propose that IL-9-producing TH cells are a phenotypically and functionally distinct subpopulation of TH2 cells that depend on PPAR-γ for full effector functions.
Assuntos
Citocinas/metabolismo , PPAR gama/metabolismo , Células Th2/citologia , Células Th2/metabolismo , Citocinas/imunologia , Dermatite Alérgica de Contato/imunologia , Dermatite Atópica/imunologia , Humanos , PPAR gama/imunologia , Psoríase/imunologia , Células Th2/imunologiaRESUMO
In the context of xenotransplantation, in ischemia/reperfusion injury as well as in cardiovascular research, the study of the fascinating interplay between endothelial cells (EC) and the plasma cascade systems often requires in vitro models. Blood vessels are hardly reproducible with standard flat-bed culture systems and flow-plate assays are limited in their low surface-to-volume ratio which impedes the study of the anticoagulant properties of the endothelial cells. According to the 3R regulations (reduce, replace and refine animal experimentation) we developed a closed circuit microfluidic in vitro system in which endothelial cells are cultured in 3D round section microchannels and subjected to physiological, pulsatile flow. In this study, a 3D monolayer of porcine aortic EC was perfused with human serum to mimic a xenotransplantation setting. Complement as well as EC activation was assessed in the presence or absence of complement inhibitors showing the versatility of the model for drug testing. Complement activation products as well as E-selectin expression were detected and visualized in situ by high resolution confocal microscopy. Furthermore, porcine pro-inflammatory cytokines as well as soluble complement components in the recirculating fluid phase were detected after human serum perfusion providing a better overview of the artificial vascular environment.
Assuntos
Técnicas de Cultura de Células , Proteínas do Sistema Complemento/genética , Células Endoteliais/imunologia , Dispositivos Lab-On-A-Chip , Animais , Aorta/imunologia , Aorta/ultraestrutura , Ativação do Complemento/efeitos dos fármacos , Inativadores do Complemento/farmacologia , Proteínas do Sistema Complemento/imunologia , Citocinas/genética , Citocinas/imunologia , Sulfato de Dextrana/farmacologia , Selectina E/genética , Selectina E/imunologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/ultraestrutura , Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/imunologia , Microscopia Confocal , Modelos Biológicos , Fluxo Pulsátil , Reologia , Suínos , Transplante HeterólogoRESUMO
If the Pharmaceutical Industry were to align to broad metrics that objectively state each product's "Safety Rating" two things would happen. First, Life Sciences companies would refocus dramatically on safety (followed by outcomes). Second, companies that have the highest aggregate "Safety Rating" would enjoy a significant competitive advantage. To achieve and maintain a high safety rating, the role of Safety officer needs to be elevated to the C-Suite.