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Updated: Jun 17, 2025
Isolation of Macrophage Subsets and Stromal Cells from Human and Mouse Myocardial Specimens
Published on: December 17, 2019
Macrophage OTUD1-CARD9 axis drives isoproterenol-induced inflammatory heart remodelling
Jinfu Qian1,2, Qinyan Wang2, Jiachen Xu1
1Department of Cardiology, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
Insights
The ovarian tumour deubiquitinase 1 (OTUD1)-Caspase-associated recruitment domain 9 (CARD9) axis promotes inflammation in isoproterenol-induced heart failure. Targeting this axis protects against heart damage.
Area of Science:
- Immunology
- Cardiovascular Biology
- Molecular Biology
Background:
- Chronic inflammation drives isoproterenol (ISO)-induced heart failure (HF).
- Caspase-associated recruitment domain (CARD) proteins are key in innate immunity inflammation.
- The role of CARDs in ISO-driven cardiac remodeling is understudied.
Purpose of the Study:
- To investigate the role of CARD9 in ISO-induced cardiac inflammation and remodeling.
- To elucidate the molecular mechanisms linking OTUD1 and CARD9 in this process.
Main Methods:
- Utilized Card9 knockout mice and reconstituted bone marrow chimeric mice.
- Conducted mechanistic studies in primary macrophages, cardiomyocytes, fibroblasts, and HEK-293T cells.
- Assessed cardiac inflammation, remodeling, and dysfunction following ISO administration.
Main Results:
- CARD9 was upregulated in ISO-infused murine hearts.
- Whole-body or myeloid-specific CARD9 deficiency inhibited ISO-induced cardiac inflammation and remodeling.
- OTUD1 enhances CARD9 activity by removing K33-linked ubiquitin, promoting CBM complex assembly and NF-κB activation.
- Myeloid-specific OTUD1 deletion attenuated ISO-induced cardiac inflammation and remodeling.
Conclusions:
- The OTUD1-CARD9 axis is a novel pro-inflammatory pathway in ISO-challenged macrophages.
- Targeting the OTUD1-CARD9 axis offers a protective strategy against ISO-induced heart failure.
Background:
Chronic inflammation contributes to the progression of isoproterenol (ISO)-induced heart failure (HF). Caspase-associated recruitment domain (CARD) families are crucial proteins for initiation of inflammation in innate immunity. Nonetheless, the relevance of CARDs in ISO-driven cardiac remodelling is little explored.
Methods:
This study utilized Card9-/- mice and reconstituted C57BL/6 mice with either Card9-/- or Otud1-/- marrow-derived cells. Mechanistic studies were conducted in primary macrophages, cardiomyocytes, fibroblasts and HEK-293T cells.
Results:
Here, we demonstrated that CARD9 was substantially upregulated in murine hearts infused with ISO. Either whole-body CARD9 knockout or myeloid-specific CARD9 deletion inhibited ISO-driven murine cardiac inflammation, remodelling and dysfunction. CARD9 deficiency in macrophages prevented ISO-induced inflammation and alleviated remodelling changes in cardiomyocytes and fibroblasts. Mechanistically, we found that ISO enhances the activity of CARD9 by upregulating ovarian tumour deubiquitinase 1 (OTUD1) in macrophages. We further demonstrated that OTUD1 directly binds to the CARD9 and then removes the K33-linked ubiquitin from CARD9 to promote the assembly of the CARD9-BCL10-MALT1 (CBM) complex, without affecting CARD9 stability. The ISO-activated CBM complex results in NF-κB activation and macrophage-based inflammatory gene overproduction, which then enhances cardiomyocyte hypertrophy and fibroblast fibrosis, respectively. Myeloid-specific OTUD1 deletion also attenuated ISO-induced murine cardiac inflammation and remodelling.
Conclusions:
These results suggested that the OTUD1-CARD9 axis is a new pro-inflammatory signal in ISO-challenged macrophages and targeting this axis has a protective effect against ISO-induced HF.
Key Points:
Macrophage CARD9 was elevated in heart tissues of mice under chronic ISO administration. Either whole-body CARD9 knockout or myeloid-specific CARD9 deficiency protected mice from ISO-induced inflammatory heart remodeling. ISO promoted the assembly of CBM complex and then activated NF-κB signaling in macrophages through OTUD1-mediated deubiquitinating modification. OTUD1 deletion in myeloid cells protected hearts from ISO-induced injuries in mice.
