XCR1+ conventional dendritic cell-induced CD4+ T helper 1 cell activation exacerbates cardiac remodeling after ischemic myocardial injury

The Immune System, An Arrow into the Heart. Principles of Cardioimmunology, An Emerging Branch in Medicine

Cardioimmunology is an emerging branch of medicine whose development has been facilitated by more sophisticated diagnostic procedures. Recent studies have mainly focused on the immune response during myocardial infarction (MI), and there is evidence that both resident and external immune cells participate in acute inflammatory disease, as well as tissue remodeling. Following MI, macrophages, dendritic cells (DCs) and mast cells (MCs) are the main players in the heart. Under steady-state conditions, cardiac resident macrophages (CRMs) protect the heart against stress and infectious events, being involved in cell and matrix turnover, as well as phagocytosis of apoptotic cells. Moreover, CRMs contribute to the resolution of inflammation via release of interleukin (IL)-10, and efferocytosis of dying cells. Conversely, CCR2+ monocytederived macrophages promote inflammation in the acute phase of myocardial damage, with the release of pro-inflammatory cytokines. Conventional (c) DCs possess enhanced capacity to present antigens to T lymphocytes. In MI patient autopsies, massive infiltration of T helper (Th) cells and CDs has been detected in the myocardium. Cardiac MCs play a dual role during MI, with the production of cytokines for early inflammatory response, and the release of anti-inflammatory cytokines, IL10 and IL-13 during the resolution phase. In experimental coronary artery ligation, the myocardium is infiltrated with Th1, Th2, Th17, and T regulatory (TREG) cells, which participate in the acute inflammation. In cardiac repair, T cell reparative response is mediated by TREG cells, with improved ventricular remodeling and function post-ischemia. In this review, emphasis will be placed on the innate and adaptive immune response during and post-MI. At the same time, immunotherapy- based cardiac failure following chimeric antigen receptor T-cell and immune checkpoint inhibitory therapy will be pointed out.

Leukocyte-lymphatic intersections during cardiac inflammation

Advances in genetic, pharmacologic, and sequencing technology have led to new insight into the role of lymphatics in health and disease. This includes fundamental aspects of the crosstalk between immune cells with cardiac lymphatics. At the interface between leukocytes and lymphatic endothelial cells, myeloid populations are sources of lymphatic growth factors during inflammation. Lymphatic endothelial cells also secrete signals that activate leukocytes, including to antigen presenting cells. Taken together, a view of the lymphatic vasculature as a supplemental cardiac immune hub is emerging. Herein, we discuss reciprocal cell and molecular crosstalk between leukocytes and lymphatics in the myocardium, with implications for health and cardiac inflammation.

Unraveling the role of lactate-related genes in myocardial infarction

Background

Lactate is a crucial intermediary, facilitating communication between myocardial energy metabolism and microenvironmental regulation. The present study aimed to investigate the relationship between lactate-related genes (LRGs) and myocardial infarction (MI).

Methods

A total of 23 LRGs exhibited differential expression between individuals with MI and healthy controls. Lasso regression analysis and validation with the GSE61144 dataset identified three hub genes: COX20, AGK, and PDHX. Single-gene GSEA of these genes revealed strong enrichment in pathways related to amino acid metabolism, cell cycle, and immune functions. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was utilized to validate the expression levels of the hub genes.

Results

Immune infiltration analysis revealed differences in CD4+ T and CD8+ T cells between the MI and control groups. Additionally, 67 candidate drugs targeting the three hub LRGs were identified, and a ceRNA network was constructed to explore the intricate interactions among these genes.

Conclusions

These findings enhance the understanding of MI and have potential therapeutic implications.

Emerging Roles for Dendritic Cells in Heart Failure

The field of cardio-immunology has emerged from discoveries that define roles for innate and adaptive immune responses associated with myocardial inflammation and heart failure. Dendritic cells (DCs) comprise an important cellular compartment that contributes to systemic immune surveillance at the junction of innate and adaptive immunity. Once described as a singular immune subset, we now appreciate that DCs consist of a heterogeneous pool of subpopulations, each with distinct effector functions that can uniquely regulate the acute and chronic inflammatory response. Nevertheless, the cardiovascular-specific context involving DCs in negotiating the biological response to myocardial injury is not well understood. Herein, we review our current understanding of the role of DCs in cardiac inflammation and heart failure, including gaps in knowledge and clinical relevance.