Biology subjects

Heieis, G. A.

Publications and source records attributed to Heieis, G. A..

4 recordsLinked to original sources

bioRxiv2023

A PD-1-ST2 axis controls Th2 effector function in tissue via a metabolic checkpoint

Type 2 immune responses characterise both helminth infections and atopic disease such as allergy or asthma, but a better understanding of the mechanisms that regulate these responses is key to improving therapeutic and vaccination strategies. Immuno-metabolic studies over the last two decades have suggested T cell activation broadly requires rapid increases in glycolysis and oxidative phosphorylation. In contrast, we show that CD4+ T helper 2 (Th2) cells activated in vivo, using models of helminth infection, do not acquire a glycolytic metabolism. Instead, we show that Th2 cells solely increase their oxidative metabolism, associated with increased fatty acid uptake. Rather than contributing directly to effector function, our data reveal that Th2 cells switch to fatty acid oxidation downstream of PD-1 signalling to promote expression of the IL-33 receptor (ST2). These data provide insight into the spatial regulation of T cell metabolism, and suggest that PD-1 blockade therapies may be effective in Th2 disorders.

immunology↗

bioRxiv2022

Spectral flow cytometry reveals metabolic heterogeneity in tissue macrophages

Tissue-macrophage populations are constituted by a mosaic of phenotypes, yet new methods are needed to link metabolic status to the range of phenotypes in vivo. We therefore designed a high-dimensional panel for spectral flow cytometry to investigate the heterogeneity of tissue macrophage metabolism at steady-state, and their metabolic adaptation in response to infection. Distinct metabolic profiles were observed between tissue macrophages from different peripheral organs, as well as within populations from a specific site. As such, our data show multiple metabolic states in macrophages corresponding to relative stages of maturity in both the peritoneal cavity and small intestine. Immune perturbation with helminth infection further showed that peritoneal macrophages acquire an overall highly metabolically active profile, whereas responding intestinal macrophages displayed minimal changes in their metabolic phenotype. Thus, we demonstrate that high-dimensional, flow-based analysis is an exciting method to interrogate the metabolic heterogeneity and dynamics of tissue-macrophage populations.

immunology↗

bioRxiv2021

LKB1 signalling in dendritic cells controls whole-body metabolic homeostasis by limiting T helper 17 priming

Obesity-associated metaflammation drives the development of insulin resistance and type 2 diabetes, notably through modulating innate and adaptive immune cells in metabolic organs. The nutrient sensor liver kinase B1 (LKB1) has recently been shown to control cellular metabolism and T cell priming functions of dendritic cells (DCs). Here, we report that hepatic DCs from high-fat diet (HFD)-fed obese mice display increased LKB1 phosphorylation and that LKB1 deficiency in DCs (CD11c{Delta}LKB1) worsened HFD-driven hepatic steatosis, systemic insulin resistance and glucose intolerance. Loss of LKB1 in DCs was associated with increased cellular expression of Th17-polarizing cytokines and increased hepatic CD4+ IL-17A+ Th17 cells in HFD-fed mice. Importantly, IL-17A neutralization rescued metabolic perturbations in HFD-fed CD11c{Delta}LKB1 mice. Mechanistically, disrupted metabolic homeostasis was independent of the canonical LKB1-AMPK axis. Instead, we provide evidence for involvement of the AMPK-related salt-inducible kinase(s) in controlling Th17-polarizing cytokine expression in LKB1-deficient DCs. Altogether, our data reveal a key role for LKB1 signalling in DCs in protection against obesity-induced metabolic dysfunctions by limiting hepatic Th17 differentiation.

immunology↗

bioRxiv2021

Tissue-based IL-10 signalling in helminth infection limits IFNγ expression and promotes the intestinal Th2 response

Type 2 immunity is activated in response to both allergens and helminth infection. It can be detrimental or beneficial, and there is a pressing need to better understand its regulation. The immunosuppressive cytokine IL-10 is known as a T helper 2 (Th2) effector molecule, but it is currently unclear whether IL-10 dampens or promotes Th2 differentiation during infection. Here we show that helminth infection in mice elicits IL-10 expression in both the intestinal lamina propria and the draining mesenteric lymph node, with higher expression in the infected tissue. In vitro, exogenous IL-10 enhanced Th2 differentiation in isolated CD4+ T cells, increasing expression of GATA3 and production of IL-5 and IL-13. The ability of IL-10 to amplify the Th2 response coincided with its suppression of IFN{gamma} expression and, in vivo, we found that, in intestinal helminth infection, IL-10 receptor expression was higher on Th1 cells in the small intestine than on Th2 cells in the same tissue, or on any Th cell in the draining lymph node. In vivo blockade of IL-10 signalling during helminth infection resulted in an expansion of IFN{gamma}+ and Tbet+ Th1 cells in the small intestine and caused a coincident decrease in IL-13, IL-5 and GATA3 expression by intestinal T cells. Together our data indicate that IL-10 signalling promotes Th2 differentiation during helminth infection at least in part by regulating competing Th1 cells in the infected tissue.

immunology↗