TAK1-AMPK Pathway in Macrophages Regulates Hypothyroid Atherosclerosis

Purpose: Hypothyroidism (HT) is associated with accelerated atherosclerosis (AS). The efficacy of traditional strategies of hypothyroid AS remains controversial. Here, we aimed to deepen the understanding of the HT-induced acceleration of AS, to decrease the residual risk of coronary artery disease (CAD) and to find a new therapeutic target.

Methods: We collected peripheral venous blood samples from 20 patients and divided them into 4 groups, namely, the normal group, the HT group, the CAD group and the HT + CAD group. Then we performed mRNA microarray analysis and bioinformatics analysis to screen the differentially expressed genes and pathways, and we also conducted validations on apoE knockout mice models and Raw264.7 cell models.

Results: In short, (1) in the analysis between the CAD group and the HT + CAD group, we found a total of 1218 differentially expressed genes, 11 upregulated pathways and 40 downregulated pathways. (2) We validated that patients with HT and CAD had a significantly decreased expression of MAP3K7 (encoding transforming growth factor-β-activated kinase 1, TAK1) gene than normal subjects. (3) In animal and cell experiments, we found the decreased expression of TAK1 and the reduced phosphorylation of AMP-activated protein kinase (AMPK) under the hypothyroid and atherosclerotic condition. (4) Changes in the expressions of TAK1 may affect the progression of AS.

Conclusion: Taken together, these data suggest that the accelerated AS in hypothyroid patients may be due to the suppression of TAK1-AMPK pathway in macrophages. This new finding may become a novel therapeutic target in hypothyroid AS.