Rational: In patients with Type 2 diabetes mellitus (T2DM), increased cardiovascular morbidity and mortality is associated with accelerated vascular calcification (VC). Despite progress in treatment and diagnosis of cardiovascular disease (CVD) in the past few decades, VC persists as a CVD risk factor without a therapeutic approach to either inhibit or halt its progression. Therefore, the aim of the study is a better understanding of the underlying pathological mechanisms and discovery of potential novel therapeutic pathway targets in glucose-related VC applying the emerging concept of targeting a multi-omics network.

Methods and Results: Human coronary artery smooth muscle cells (SMCs) were cultured with 0 mM, 5.5 mM, and 25 mM glucose under calcifying conditions (3 mM calcium, 2 mM phosphate). Glucose promoted extracellular matrix calcification in SMCs in a dose- and time-dependent manner without affecting cellular viability and metabolic activity. Absence of glucose fully inhibited SMC calcification. We applied an untargeted metabolomic and transcriptomic approach at two different time points for cell lysates and their secretome to identify key molecular drivers in glucose-induced VC (Figure). Transcriptomic analysis revealed 3,187 unique genes differentially expressed glucose-dependently. The metabolomic screening identified 571 metabolites. Independent principal component analysis from both transcriptomics and metabolomics discriminated cellular profiles induced by glucose. Differentially expressed metabolites and genes were integrated reconstructing a co-expression network using the web based tool OmicsNet. Key players from the hypotaurine/taurine metabolic pathway, such as the metabolites cysteine sulfinic acid, hypotaurine and alpha-butyrate, interacted in the multi-omics network. Analysis of statistically significant metabolites identified by two-way ANOVA (p=0.05) revealed hypotaurine to be dose-dependently secreted by glucose treatment. Further, flavin-containing monooxygenase (FMO1) - the enzyme converting hypotaurine to taurine – as well as the hypotaurine transporter SLC6A6 were dysregulated by high glucose in the transcriptome data set. Validation by qPCR revealed a glucose-dependent induction of FMO1 (+3.2 fold, p=0.01) and SLC6A6 (+1.8 fold, p=0.03). In calcifying SMCs, hypotaurine treatment dose-dependently decreased extracellular matrix mineralization assessed by alizarin red S staining (-1.8 fold, p=0.01).

Conclusion: Our multi-omics analysis supports a functional role of hypotaurine/taurine metabolic pathway in glucose-dependent VC, suggesting potential novel therapeutic targets that warrant further investigation for VC in T2DM.