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Updated: Jul 23, 2025
Pull-down of Calmodulin-binding Proteins
Published on: January 23, 2012
Downregulated calmodulin expression contributes to endothelial cell impairment in diabetes
Tian-Tian Liu1, Huan-Huan Xu1, Ze-Juan Liu1
1Department of Pharmacology, Beijing Key Laboratory of Cardiovascular Diseases Related to Metabolic Disturbance, Capital Medical University, Beijing, 100069, China.
Abstract:
Endothelial dysfunction, a central hallmark of cardiovascular pathogenesis in diabetes mellitus, is characterized by impaired endothelial nitric oxide synthase (eNOS) and NO bioavailability. However, the underlying mechanisms remain unclear. Here in this study, we aimed to identify the role of calmodulin (CaM) in diabetic eNOS dysfunction. Human umbilical vein endothelial cells and murine endothelial progenitor cells (EPCs) treated with high glucose (HG) exhibited downregulated CaM mRNA/protein and vascular endothelial growth factor (VEGF) expression with impeded eNOS phosphorylation and cell migration/tube formation. These perturbations were reduplicated in CALM1-knockdown cells but prevented in CALM1-overexpressing cells. EPCs from type 2 diabetes animals behaved similarly to HG-treated normal EPCs, which could be rescued by CALM1-gene transduction. Consistently, diabetic animals displayed impaired eNOS phosphorylation, endothelium-dependent dilation, and CaM expression in the aorta, as well as deficient physical interaction of CaM and eNOS in the gastrocnemius. Local CALM1 gene delivery into a diabetic mouse ischemic hindlimb improved the blunted limb blood perfusion and gastrocnemius angiogenesis, and foot injuries. Diabetic patients showed insufficient foot microvascular autoregulation, eNOS phosphorylation, and NO production with downregulated CaM expression in the arterial endothelium, and abnormal CALM1 transcription in genome-wide sequencing analysis. Therefore, our findings demonstrated that downregulated CaM expression is responsible for endothelium dysfunction and angiogenesis impairment in diabetes, and provided a novel mechanism and target to protect against diabetic endothelial injury.
Insights
Downregulated calmodulin (CaM) impairs endothelial nitric oxide synthase (eNOS) function in diabetes. Restoring CaM levels protects against diabetic endothelial dysfunction and promotes blood vessel repair.
Area of Science:
- Cardiovascular Biology
- Endothelial Cell Biology
- Diabetes Pathogenesis
Background:
- Endothelial dysfunction is a key factor in diabetes-related cardiovascular disease.
- Impaired endothelial nitric oxide synthase (eNOS) activity and nitric oxide (NO) bioavailability are central to this dysfunction.
- The precise mechanisms driving diabetic eNOS dysfunction are not fully understood.
Purpose of the Study:
- To investigate the role of calmodulin (CaM) in endothelial nitric oxide synthase (eNOS) dysfunction observed in diabetes mellitus.
- To elucidate the molecular mechanisms linking CaM to endothelial health in diabetic conditions.
Main Methods:
- Utilized human umbilical vein endothelial cells and murine endothelial progenitor cells (EPCs) exposed to high glucose (HG).
- Assessed CaM, vascular endothelial growth factor (VEGF), and eNOS phosphorylation levels.
- Employed CALM1 gene knockdown and overexpression techniques.
- Studied diabetic animal models and human patient samples, including gene sequencing and gene delivery interventions.
Main Results:
- High glucose exposure led to reduced CaM and VEGF expression, impaired eNOS phosphorylation, and decreased cell migration/tube formation in endothelial cells.
- CALM1 knockdown mimicked these effects, while CALM1 overexpression rescued them.
- Diabetic animals and patients exhibited decreased CaM expression, eNOS phosphorylation, and impaired vascular function.
- Local CALM1 gene delivery improved blood perfusion, angiogenesis, and wound healing in diabetic mouse models.
Conclusions:
- Downregulated calmodulin (CaM) expression is a critical factor underlying endothelial dysfunction and impaired angiogenesis in diabetes.
- Reduced CaM disrupts eNOS phosphorylation and NO bioavailability, contributing to diabetic vascular complications.
- CaM represents a novel therapeutic target for mitigating diabetic endothelial injury and its associated cardiovascular risks.
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