Identifying metabolic targets to reinvigorate t cell exhaustion

The National Institute of Allergy and Infectious Diseases awarded The Johns Hopkins University $197,600 on September 21, 2025, under the Allergy and Infectious Diseases Research program (CFDA 93.855) to identify metabolic targets that can reinvigorate exhausted CD8+ T cells. The award is classified as a Project Grant.

The research applies untargeted liquid chromatography-mass spectrometry-based metabolomics to characterize the distinct metabolic profile of exhausted T cells compared to functional effector T cells. Exhausted T cells, which arise after prolonged antigen exposure, are characterized by stable expression of inhibitory surface receptors, poor response to tumor antigens, and low cell proliferation—conditions that reduce effectiveness of immune checkpoint inhibitors. The investigator hypothesizes that chronic T-cell receptor stimulation imposes unique metabolic constraints that can be targeted by overexpressing metabolic genes to reprogram exhausted T cells and restore immune function.

Performance occurs in Baltimore, Maryland, with a period of performance from September 21, 2025, through April 30, 2027.

Abstract

CD8+ t cells are a critical component of the adaptive immune system and play an essential role in immune defense against viruses, bacteria, and tumors. To achieve such a critical function in many different contexts, CD8+ t cells have evolved to be highly adaptive by modulating cellular metabolism. Activated effector t cells require high metabolic flux through anabolic growth-promoting pathways, while quiescent or more resting states engage catabolic processes for ATP generation. After prolonged antigen exposure, CD8+ t cells can become dysfunctional as they enter a distinct differentiation state known as t-cell exhaustion. This dysfunctional state of t cells is characterized by stable expression of inhibitory surface receptors, poor response to tumor antigens, and low cell proliferation and persistence of t cells in vivo, dampening immunity and causing poor responsiveness to immune checkpoint inhibitors. Growing evidence indicates that exhausted t cells are 'metabolically insufficient' with altered signaling cascades and transcriptional and epigenetic landscapes. Metabolites are not simply byproducts of the differentiation of t cells, but metabolism itself may dictate t cell exhaustion. Hence, modulating metabolism might reprogram or rewire certain states of t cell differentiation. However, how metabolic rewiring drives and defines the differentiation of t cell exhaustion remains unclear. We applied an untargeted liquid chromatography-mass spectrometry-based metabolomics approach and found exhausted t cells display a distinct metabolic profile compared to functional effector t cells. We thus hypothesize that chronic TCR stimulation imposes unique constraints on t cell metabolism that can be targeted to reinvigorate exhausted t cells by overexpressing metabolic genes. Encouraged by a striking metabolic difference between exhausted t cells and effector t cells, we will use unbiased genetic and systems approaches to understand the functional relevance of metabolic pathways in CD8+ t cell immunity. Several loss-of-function (LOF) screen studies have recently identified that remodeling metabolism is intrinsically linked to cellular development, activation, function, differentiation, and survival in t- cell biology. However, the comprehensive discovery of regulators requires both gain-of-function (GOF) and LOF approaches. In aim 1, we performed a functional genomic screen in vitro using a metabolism-focused crispr activation library to identify potential gain-of-function metabolic targets that limit t cell persistence. In aim 2, we will determine the molecular mechanism by which the newly revealed GOF candidates reinvigorate t cell exhaustion. The interactive analysis of the collected data will allow US to define the molecular mechanisms by which metabolic pathways regulate t cell exhaustion. Collectively, we hope that our work will provide insight into how to therapeutically modulate metabolism to restore exhausted t cells.