Proteomic and functional comparison between human induced and embryonic stem cells.

Human induced pluripotent stem cells (hiPSCs) have great potential to be used as alternatives to embryonic stem cells (hESCs) in regenerative medicine and disease modelling. In this study, we characterise the proteomes of multiple hiPSC and hESC lines derived from independent donors and find that while they express a near-identical set of proteins, they show consistent quantitative differences in the abundance of a subset of proteins. hiPSCs have increased total protein content, while maintaining a comparable cell cycle profile to hESCs, with increased abundance of cytoplasmic and mitochondrial proteins required to sustain high growth rates, including nutrient transporters and metabolic proteins.

Deep proteomic analysis of microglia reveals fundamental biological differences between model systems.

Using high-resolution quantitative mass spectrometry, we present comprehensive human and mouse microglia proteomic datasets consisting of over 11,000 proteins across six microglia groups. Microglia share a core protein signature of over 5,600 proteins, yet fundamental differences are observed between species and culture conditions. Mouse microglia demonstrate proteome differences in inflammation- and Alzheimer's disease-associated proteins.

Airway macrophage glycolysis controls lung homeostasis and responses to aeroallergen.

The lungs represent a dynamic microenvironment where airway macrophages (AMs) are the major lung-resident macrophages. AMs dictate the balance between tissue homeostasis and immune activation and thus have contradictory functions by maintaining tolerance and tissue homeostasis, as well as initiating strong inflammatory responses. Emerging evidence has highlighted the connection between macrophage function and cellular metabolism.

Extracellular vesicles in COVID-19 convalescence can regulate T cell metabolism and function.

Long-term T cell dysregulation has been reported following COVID-19 disease. Prolonged T cell activation is associated with disease severity and may be implicated in producing long-covid symptoms. Here, we assess the role of extracellular vesicles (EV) in regulating T cell function over several weeks post COVID-19 disease.

QUAS-R: An SLC1A5-mediated glutamine uptake assay with single-cell resolution reveals metabolic heterogeneity with immune populations.

System-level analysis of single-cell data is rapidly transforming the field of immunometabolism. Given the competitive demand for nutrients in immune microenvironments, there is a need to understand how and when immune cells access these nutrients. Here, we describe a new approach for single-cell analysis of nutrient uptake where we use in-cell biorthogonal labeling of a functionalized amino acid after transport into the cell.

Glycogen-fuelled metabolism supports rapid mucosal-associated invariant T cell responses.

Mucosal-associated invariant T (MAIT) cells are a subset of unconventional T cells which recognize a limited repertoire of ligands presented by the MHC class-I like molecule MR1. In addition to their key role in host protection against bacterial and viral pathogens, MAIT cells are emerging as potent anti-cancer effectors. With their abundance in human, unrestricted properties, and rapid effector functions MAIT cells are emerging as attractive candidates for immunotherapy.

Canagliflozin impairs T cell effector function via metabolic suppression in autoimmunity.

Augmented T cell function leading to host damage in autoimmunity is supported by metabolic dysregulation, making targeting immunometabolism an attractive therapeutic avenue. Canagliflozin, a type 2 diabetes drug, is a sodium glucose co-transporter 2 (SGLT2) inhibitor with known off-target effects on glutamate dehydrogenase and complex I. However, the effects of SGLT2 inhibitors on human T cell function have not been extensively explored.

The proliferation of human mucosal-associated invariant T cells requires a MYC-SLC7A5-glycolysis metabolic axis.

Mucosal-associated invariant T (MAIT) cells are an abundant population of innate T cells that recognize bacterial ligands and play a key role in host protection against bacterial and viral pathogens. Upon activation, MAIT cells undergo proliferative expansion and increase their production of effector molecules such as cytokines. In this study, we found that both mRNA and protein abundance of the key metabolism regulator and transcription factor MYC was increased in stimulated MAIT cells.

Amino acid availability acts as a metabolic rheostat to determine the magnitude of ILC2 responses.

Group 2 innate lymphoid cells (ILC2) are functionally poised, tissue-resident lymphocytes that respond rapidly to damage and infection at mucosal barrier sites. ILC2 reside within complex microenvironments where they are subject to cues from both the diet and invading pathogens-including helminths. Emerging evidence suggests ILC2 are acutely sensitive not only to canonical activating signals but also perturbations in nutrient availability.

A glutamine 'tug-of-war': targets to manipulate glutamine metabolism for cancer immunotherapy.

Within the tumour microenvironment (TME), there is a cellular 'tug-of-war' for glutamine, the most abundant amino acid in the body. This competition is most evident when considering the balance between a successful anti-tumour immune response and the uncontrolled growth of tumour cells that are addicted to glutamine. The differential effects of manipulating glutamine abundance in individual cell types is an area of intense research and debate.

Single Cell Glucose Uptake Assays: A Cautionary Tale.

Assays to monitor the metabolic state or nutrient uptake capacity of immune cells at a single cell level are increasingly in demand. One assay, used by many immunologists, employs 2-(-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)Amino)-2-Deoxyglucose (2-NBDG), a fluorescent analogue of 2-deoxyglucose (2DG), as a substrate for glucose transporters. This molecule has been validated as a substrate for the glucose transporter Glut2 (Slc2a2) in mammalian cells but 2-NDBG selectivity for the glucose transporters expressed by T cells, Glut1 (Slc2a1) and Glut3 (Slc2a3), has never been explored.

Exhausted CD4 T Cells during Malaria Exhibit Reduced mTORc1 Activity Correlated with Loss of T-bet Expression.

CD4 T cell functional inhibition (exhaustion) is a hallmark of malaria and correlates with impaired parasite control and infection chronicity. However, the mechanisms of CD4 T cell exhaustion are still poorly understood. In this study, we show that Ag-experienced () CD4 T cell exhaustion during nonlethal infection occurs alongside the reduction in mammalian target of rapamycin (mTOR) activity and restriction in CD4 T cell glycolytic capacity.

Quantitative analysis of how Myc controls T cell proteomes and metabolic pathways during T cell activation.

T cell expansion and differentiation are critically dependent on the transcription factor c-Myc (Myc). Herein we use quantitative mass-spectrometry to reveal how Myc controls antigen receptor driven cell growth and proteome restructuring in murine T cells. Analysis of copy numbers per cell of >7000 proteins provides new understanding of the selective role of Myc in controlling the protein machinery that govern T cell fate.

Obesity Reduces mTORC1 Activity in Mucosal-Associated Invariant T Cells, Driving Defective Metabolic and Functional Responses.

Obesity underpins the development of numerous chronic diseases, such as type II diabetes mellitus. It is well established that obesity negatively alters immune cell frequencies and functions. Mucosal-associated invariant T (MAIT) cells are a population of innate T cells, which we have previously reported are dysregulated in obesity, with altered circulating and adipose tissue frequencies and a reduction in their IFN-γ production, which is a critical effector function of MAIT cells in host defense.

Antigen receptor control of methionine metabolism in T cells.

Immune activated T lymphocytes modulate the activity of key metabolic pathways to support the transcriptional reprograming and reshaping of cell proteomes that permits effector T cell differentiation. The present study uses high resolution mass spectrometry and metabolic labelling to explore how murine T cells control the methionine cycle to produce methyl donors for protein and nucleotide methylations. We show that antigen receptor engagement controls flux through the methionine cycle and RNA and histone methylations.

Amino acid-dependent cMyc expression is essential for NK cell metabolic and functional responses in mice.

Natural killer (NK) cells are lymphocytes with important anti-tumour functions. Cytokine activation of NK cell glycolysis and oxidative phosphorylation (OXPHOS) are essential for robust NK cell responses. However, the mechanisms leading to this metabolic phenotype are unclear.

Single cell analysis of kynurenine and System L amino acid transport in T cells.

The tryptophan metabolite kynurenine has critical immunomodulatory properties and can function as an aryl hydrocarbon receptor (AHR) ligand. Here we show that the ability of T cells to transport kynurenine is restricted to cells activated by the T-cell antigen receptor or proinflammatory cytokines. Kynurenine is transported across the T-cell membrane by the System L transporter SLC7A5.

Interleukin-2 shapes the cytotoxic T cell proteome and immune environment-sensing programs.

Interleukin-2 (IL-2) and Janus kinases (JAKs) regulate transcriptional programs and protein synthesis to promote the differentiation of effector CD8 cytotoxic T lymphocytes (CTLs). Using high-resolution mass spectrometry, we generated an in-depth characterization of how IL-2 and JAKs configure the CTL proteome to control CTL function. We found that IL-2 signaling through JAK1 and JAK3 (JAK1/3) increased the abundance of a key subset of proteins to induce the accumulation of critical cytokines and effector molecules in T cells.

Glucose represses dendritic cell-induced T cell responses.

Glucose and glycolysis are important for the proinflammatory functions of many immune cells, and depletion of glucose in pathological microenvironments is associated with defective immune responses. Here we show a contrasting function for glucose in dendritic cells (DCs), as glucose represses the proinflammatory output of LPS-stimulated DCs and inhibits DC-induced T-cell responses. A glucose-sensitive signal transduction circuit involving the mTOR complex 1 (mTORC1), HIF1α and inducible nitric oxide synthase (iNOS) coordinates DC metabolism and function to limit DC-stimulated T-cell responses.

Nutrient sensing, signal transduction and immune responses.

Most cells in the body have a constant supply of nutrients, which are required to sustain cellular metabolism and functions. In contrast, cells of the immune system can encounter conditions with a limited nutrient supply during the course of an immune response. Cells of the immune system frequently operate in complex nutrient restricted microenvironments such as tumour or inflammatory sites.

Single cell tuning of Myc expression by antigen receptor signal strength and interleukin-2 in T lymphocytes.

Myc controls the metabolic reprogramming that supports effector T cell differentiation. The expression of Myc is regulated by the T cell antigen receptor (TCR) and pro-inflammatory cytokines such as interleukin-2 (IL-2). We now show that the TCR is a digital switch for Myc mRNA and protein expression that allows the strength of the antigen stimulus to determine the frequency of T cells that express Myc.