The immune checkpoint TIM-3/HMGB-1 axis in myocardial infarction – Nature

Report on the Immune Checkpoint TIM-3/HMGB-1 Axis in Myocardial Infarction and Its Implications for Sustainable Development Goals

Introduction

Immune checkpoints (ICs) are critical regulators of immune responses, acting as inhibitory switches on immune cells. While extensively studied in cancer treatment, their role in cardiovascular diseases, particularly myocardial infarction (MI), remains underexplored. This report focuses on the T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) pathway and its ligands, emphasizing their association with cardiac remodeling post-MI. The study integrates serum analysis, peripheral blood mononuclear cells (PBMCs), and cardiac tissue investigations.

Relevance to Sustainable Development Goals (SDGs)

• SDG 3: Good Health and Well-being – Understanding immune mechanisms in MI contributes to improved cardiovascular health and therapeutic strategies.
• SDG 9: Industry, Innovation, and Infrastructure – Utilization of advanced single-cell RNA sequencing and spatial transcriptomics fosters innovation in biomedical research.
• SDG 17: Partnerships for the Goals – Collaborative research across institutions and countries enhances scientific progress.

Findings

1. Association of Circulating TIM-3 Ligands with Cardiac Remodeling Post-MI

Analysis of 357 patients from the GIPS-III trial revealed significant associations between serum levels of TIM-3 ligands—galectin-9 (Gal-9), high mobility group box-1 (HMGB-1), and carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1)—and cardiac remodeling parameters four months after MI.

1. Gal-9 levels at 24 hours post-MI correlated with increased infarct size.
2. HMGB-1 and CEACAM1 levels were associated with reduced left ventricular ejection fraction (LVEF).
3. Multivariate analyses confirmed Gal-9 and HMGB-1 as independent predictors of cardiac remodeling.

These findings highlight the potential of TIM-3 ligands as biomarkers for cardiac injury and remodeling, contributing to SDG 3 by improving disease monitoring and management.

2. TIM-3 Expression Dynamics in Peripheral Blood Immune Cells Post-MI

Single-cell RNA sequencing of PBMCs from 38 MI patients and 38 controls showed:

• Acute downregulation of TIM-3 gene (HAVCR2) in lymphoid cells (CD4+, CD8+ T cells, and natural killer cells) within 24 hours post-MI.
• Myeloid cells maintained TIM-3 expression during the acute phase but showed downregulation after eight weeks.

This temporal regulation suggests a complex immune modulation following MI, with implications for targeted immunotherapies, aligning with SDG 3 and SDG 9.

3. Spatial and Cellular Expression of TIM-3 and Its Ligands in Human Cardiac Tissue

Single-nucleus RNA sequencing and spatial transcriptomics of myocardial tissue from different zones (ischemic, border, remote, fibrotic) revealed:

• Upregulation of HMGB-1 by cardiomyocytes, especially in the ischemic zone.
• Gal-9 upregulated in the ischemic zone; phosphatidylserine synthase 1 (PSS1) downregulated in ischemic and fibrotic zones.
• Predicted ligand-receptor interactions indicated prominent communication between cardiomyocyte-derived HMGB-1 and TIM-3 on myeloid cells.
• Spatial colocalization confirmed the interaction predominantly in the ischemic zone.

These insights into cellular crosstalk provide avenues for novel therapeutic targets to mitigate cardiac inflammation and remodeling, supporting SDG 3 and fostering innovation under SDG 9.

4. TIM-3 Expression in Pro-inflammatory Macrophages

Subclustering of myeloid cells identified three macrophage populations:

• SPP1+ macrophages: Pro-inflammatory, predominant in the ischemic zone, with high TIM-3 expression and NLRP3 inflammasome activity.
• LYVE+ resident macrophages: Present in all zones.
• CCL18+ macrophages: Anti-inflammatory, associated with reparative phases.

The elevated TIM-3 in pro-inflammatory macrophages suggests a role in modulating inflammation post-MI, relevant to SDG 3.

5. In Vitro Validation of HMGB-1 Induced Macrophage Polarization via TIM-3

Macrophages stimulated with HMGB-1 in vitro demonstrated:

• Induction of M1 pro-inflammatory polarization, evidenced by increased IL6 and CXCL10 expression.
• Upregulation of TIM-3 gene expression upon HMGB-1 stimulation.
• Blockade of TIM-3 or RAGE receptors prevented HMGB-1-induced M1 polarization and inflammasome pathway activation (CASP1, IL1B, IL18).

This receptor-specific polarization underscores TIM-3/HMGB-1 as a therapeutic target to control inflammation, advancing SDG 3.

6. Increased HMGB-1 Protein Expression and Translocation in Infarcted Myocardium

Immunohistochemical analyses in murine and human infarcted hearts showed:

• Significantly increased HMGB-1 protein levels in infarcted myocardium compared to controls.
• Translocation of HMGB-1 from the nucleus to cytoplasm and extracellular space, indicating active involvement in post-MI inflammation.

These protein-level changes reinforce the functional role of HMGB-1 in cardiac injury and repair, contributing to SDG 3.

Methodological Overview

Clinical and Experimental Cohorts

• GIPS-III trial: 357 MI patients without diabetes assessed for circulating IC ligands and cardiac remodeling.
• PBMC scRNAseq: 38 MI patients and 38 matched controls analyzed for TIM-3 expression dynamics.
• Human cardiac tissue snRNAseq and spatial transcriptomics from 23 MI patients and controls.
• Murine MI model: Permanent LAD ligation to study HMGB-1 protein expression.

Techniques Employed

• Enzyme-linked immunosorbent assay (ELISA) for serum ligand quantification.
• Single-cell and single-nucleus RNA sequencing for cellular transcriptomics.
• Spatial transcriptomics to map ligand-receptor colocalization.
• In vitro macrophage differentiation and stimulation assays.
• Immunohistochemistry for protein localization and expression analysis.

Data Analysis

• Linear and multivariate regression analyses for clinical associations.
• Differential gene expression and ligand-receptor interaction inference using LIANA.
• Gene ontology pathway analysis for functional insights.
• Statistical significance set at p < 0.05.

Discussion and Implications for Sustainable Development Goals

This comprehensive study elucidates the role of the TIM-3/HMGB-1 axis in myocardial infarction, revealing its involvement in cardiac inflammation and remodeling. The identification of TIM-3 ligands as biomarkers and the mechanistic insights into macrophage polarization provide a foundation for developing targeted therapies to improve cardiovascular outcomes.

These findings directly support SDG 3 (Good Health and Well-being) by advancing knowledge that may lead to enhanced prevention, diagnosis, and treatment of cardiovascular diseases, a leading cause of global mortality. The application of cutting-edge technologies such as single-cell sequencing and spatial transcriptomics exemplifies innovation in biomedical research, aligning with SDG 9 (Industry, Innovation, and Infrastructure). Furthermore, the collaborative nature of this research, involving multiple institutions and countries, embodies the spirit of SDG 17 (Partnerships for the Goals), fostering global scientific cooperation.

Conclusion

1. TIM-3 ligands, particularly HMGB-1 and Gal-9, are significantly associated with cardiac remodeling post-MI.
2. TIM-3 expression is dynamically regulated in immune cells, with myeloid cells maintaining expression during acute inflammation.
3. Cardiomyocyte-derived HMGB-1 interacts with TIM-3 on pro-inflammatory macrophages, promoting M1 polarization via NLRP3 inflammasome activation.
4. Blocking TIM-3/HMGB-1 interaction attenuates pro-inflammatory macrophage activation, presenting a potential therapeutic target.
5. These insights contribute to advancing SDGs by promoting cardiovascular health, fostering innovation, and encouraging collaborative research.

1. Sustainable Development Goals (SDGs) Addressed or Connected to the Issues Highlighted in the Article

1. SDG 3: Good Health and Well-being
   • The article focuses on myocardial infarction (MI), a major cardiovascular disease, and investigates immune checkpoint pathways involved in cardiac inflammation and remodeling post-MI.
   • The research aims to improve understanding and potential therapeutic targets for cardiac inflammation, which directly relates to promoting health and reducing mortality from non-communicable diseases.
2. SDG 9: Industry, Innovation and Infrastructure
   • The article employs advanced biomedical research techniques such as single-cell RNA sequencing, spatial transcriptomics, and in vitro macrophage stimulation models.
   • This reflects innovation in medical research infrastructure and methodologies to address cardiovascular diseases.
3. SDG 17: Partnerships for the Goals
   • The study involves multiple institutions and international collaborations, including data sharing from publicly available datasets and clinical trials.
   • This exemplifies partnerships and collaborative research essential for advancing health-related SDGs.

2. Specific Targets Under Those SDGs Identified Based on the Article’s Content

1. SDG 3: Good Health and Well-being
   • Target 3.4: By 2030, reduce by one third premature mortality from non-communicable diseases through prevention and treatment and promote mental health and well-being.
   • Target 3.8: Achieve universal health coverage, including access to quality essential health-care services and access to safe, effective, quality and affordable essential medicines and vaccines for all.
2. SDG 9: Industry, Innovation and Infrastructure
   • Target 9.5: Enhance scientific research, upgrade the technological capabilities of industrial sectors, including encouraging innovation and substantially increasing the number of research and development workers.
3. SDG 17: Partnerships for the Goals
   • Target 17.6: Enhance North-South, South-South and triangular regional and international cooperation on and access to science, technology and innovation.
   • Target 17.8: Fully operationalize the technology bank and science, technology and innovation capacity-building mechanism for least developed countries.

3. Indicators Mentioned or Implied in the Article to Measure Progress Towards the Identified Targets

1. Indicators for SDG 3 (Good Health and Well-being)
   • Indicator 3.4.1: Mortality rate attributed to cardiovascular diseases, including myocardial infarction.
   • Indicator 3.4.2: Suicide mortality rate (not directly relevant here but part of target 3.4).
   • Clinical and Biomarker Indicators:
     • Left ventricular ejection fraction (LVEF) measured by MRI as a measure of cardiac function post-MI.
     • Levels of immune checkpoint ligands in serum such as HMGB-1, Galectin-9, and CEACAM1 associated with cardiac remodeling.
     • Gene expression levels of TIM-3 and related immune markers in peripheral blood mononuclear cells (PBMCs) and cardiac tissue.
     • Inflammatory markers including NLRP3 inflammasome activity and cytokine expression (e.g., IL6, CXCL10, IL1B, IL18) as indicators of inflammation and immune response.
2. Indicators for SDG 9 (Industry, Innovation and Infrastructure)
   • Number and quality of scientific publications and clinical trials related to cardiovascular disease and immune checkpoint research.
   • Availability and use of advanced research technologies such as single-cell RNA sequencing and spatial transcriptomics.
3. Indicators for SDG 17 (Partnerships for the Goals)
   • Number of collaborative research projects and data sharing initiatives across institutions and countries.
   • Access to publicly available datasets and shared resources for scientific research.

4. Table: SDGs, Targets and Indicators Relevant to the Article

SDGs	Targets	Indicators
SDG 3: Good Health and Well-being	3.4: Reduce premature mortality from non-communicable diseases through prevention and treatment. 3.8: Achieve universal health coverage and access to quality essential health-care services.	3.4.1: Mortality rate attributed to cardiovascular diseases (including MI). Left ventricular ejection fraction (LVEF) post-MI measured by MRI. Serum levels of TIM-3 ligands: HMGB-1, Galectin-9, CEACAM1. Gene expression of TIM-3 and immune markers in PBMCs and cardiac tissue. Inflammatory cytokines and inflammasome activity (IL6, CXCL10, IL1B, IL18, NLRP3).
SDG 9: Industry, Innovation and Infrastructure	9.5: Enhance scientific research and technological capabilities.	Use and development of advanced research technologies (scRNAseq, spatial transcriptomics). Number and quality of scientific publications and clinical trials.
SDG 17: Partnerships for the Goals	17.6: Enhance international cooperation on science, technology and innovation. 17.8: Operationalize technology bank and capacity-building mechanisms.	Collaborative research projects and data sharing initiatives. Access to publicly available datasets and shared scientific resources.

Source: nature.com