Acetylation-ubiquitination crosstalk of DJ-1 mediates microcalcification formation in diabetic plaques via collagen-matrix vesicles interaction.

AIMS

Microcalcification increases the vulnerability of plaques and has become an important driver of acute cardiovascular events in diabetic patients. However, the regulatory mechanisms remain unclear. DJ-1, a multifunctional protein, may play a potential role in the development of diabetic complications. Therefore, this study aims to explore the relationship between DJ-1 and microcalcification in diabetic plaques and investigate the mechanisms.

METHODS AND RESULTS

The regulatory relationship between DJ-1 and diabetic vascular microcalcification was determined in anterior tibial arteries from diabetic foot amputated patients, a diabetic apolipoprotein E-deficient (ApoE-/-) mouse model, and a vascular smooth muscle cell (VSMC) model. The ubiquitination and acetylation levels of DJ-1 were detected, and the acetylation-ubiquitination crosstalk was explored. Then, the regulatory effects of DJ-1 on receptor for advanced glycation end products (RAGE) were clarified. Further, the role of DJ-1 in collagen-matrix vesicles (MVs) interaction in diabetic microenvironment was observed. The collagen interacting surface protein of MVs was verified with proteomics and the biomimetic MVs model. In clinical samples, the number of microcalcification nodules in anterior tibial artery plaques was negatively correlated with DJ-1 expression. In diabetic ApoE-/- mice and VSMCs models, knocking down DJ-1 significantly increased the number of microcalcified nodules. N-acetyltransferase 10 (NAT10) was an acetyltransferase of DJ-1. NAT10 could crosstalk the ubiquitination of DJ-1 and enhance the ubiquitination of DJ-1 by E3 ubiquitin ligase tripartite motif-containing protein 32 (TRIM32). Besides, the knockdown of DJ-1 activated signal transducer and activator of transcription 1 (STAT1), and then STAT1 could bind to RAGE promoter, thus up-regulating RAGE. Furthermore, the knockdown of DJ-1 significantly promoted collagen-MVs interaction in diabetic microenvironment. Milk fat globule epidermal growth factor 8 (MFGE8) may serve as a collagen-interacting protein. The coating of MFGE8 protein could increase the interaction between collagen and biomimetic MVs.

CONCLUSION

In the diabetic microenvironment, DJ-1 was a protective factor for vascular microcalcification. NAT10- and TRIM32-mediated acetylation-ubiquitination crosstalk resulted in the degradation of DJ-1. The decrease of DJ-1 could activate DJ-1/STAT1/RAGE microcalcification signal. Further, under the stimulation of DJ-1-mediated microcalcification signal, VSMCs released MVs with high abundance of MFGE8. MFGE8 promoted collagen-MVs interaction and finally accelerated the formation of microcalcification.