# Metabolic Checkpoints and Lymphoid Neogenesis in Lung Dendritic Cells: Mechanisms Guiding Tolerance and Chronic Lung Inflammation

## TL;DR

This review explores how metabolic pathways in lung dendritic cells influence immune tolerance or chronic inflammation, offering new therapeutic strategies for lung diseases.

## Contribution

The paper introduces the role of metabolic checkpoints in regulating dendritic cell function and lymphoid neogenesis in chronic lung inflammation.

## Key findings

- HIF-1α/mTOR glycolytic pathways drive inflammatory dendritic cell activity.
- AMPK-related metabolism supports tolerogenic states and inhibits PD-1/PD-L1 checkpoints.
- Metabolic pathways interact with DC subsets to regulate tertiary lymphoid structures in inflamed lungs.

## Abstract

Dendritic cells (DCs) are key sentinels in the lung mucosa that interpret environmental signals to either promote tolerance or trigger inflammation, influencing the development of chronic lung diseases. This review highlights recent mechanistic insights showing that metabolic checkpoints serve as upstream regulators of DC fate and activity: inflammatory stimuli activate HIF-1α/mTOR-linked glycolytic pathways that drive maturation, cytokine secretion, antigen presentation, and migration. In contrast, AMPK-related oxidative and lipid metabolism pathways support tolerogenic states that encourage regulatory T-cell responses and inhibit checkpoints like PD-1/PD-L1. We also present evidence that DC subset specialization (cDC1 vs. cDC2) and their tissue location interact with these metabolic pathways to regulate lymphoid tissue formation, including the development and persistence of tertiary lymphoid structures in chronically inflamed lungs. These ectopic lymphoid tissues enhance local immune responses through DC–stromal interactions and ongoing T follicular helper–B cell communication, contributing to persistent inflammation and tissue remodeling in conditions such as COPD, asthma, pulmonary hypertension, and fibrotic interstitial lung disease. Finally, we discuss the translational potential of targeting this immunometabolic–lymphoid pathway, suggesting that modulating metabolic regulators, migratory circuits, and tolerogenic programs could restore immune balance while maintaining host defense—a promising framework for developing advanced therapies for chronic lung inflammation.