SRY gene transferred by extracellular vesicles accelerates atherosclerosis by promotion of leucocyte adherence to endothelial cells

Abstract

We set out to investigate whether and how SRY (sex-determining region, Y) DNAs in plasma EVs (extracellular vesicles) is involved in the pathogenesis of atherosclerosis. PCR and gene sequencing found the SRY gene fragment in plasma EVs from male, but not female, patients; EVs from male patients with CAD (coronary artery disease) had a higher SRY GCN (gene copy number) than healthy subjects. Additional studies found that leucocytes, the major source of plasma EVs, had higher SRY GCN and mRNA and protein expression in male CAD patients than controls. After incubation with EVs from SRY-transfected HEK (human embryonic kidney)-293 cells, monocytes (THP-1) and HUVECs (human umbilical vein endothelial cells), which do not endogenously express SRY protein, were found to express newly synthesized SRY protein. This resulted in an increase in the adherence factors CD11-a in THP-1 cells and ICAM-1 (intercellular adhesion molecule 1) in HUVECs. EMSA showed that SRY protein increased the promoter activity of CD11-a in THP-1 cells and ICAM-1 in HUVECs. There was an increase in THP-1 cells adherent to HUVECs after incubation with SRY-EVs. SRY DNAs transferred from EVs have pathophysiological significance in vivo; injection of SRY EVs into ApoE-/- (apolipoprotein-knockout) mice accelerated atherosclerosis. The SRY gene in plasma EVs transferred to vascular endothelial cells may play an important role in the pathogenesis of atherosclerosis; this mechanism provides a new approach to the understanding of inheritable CAD in men.

Indication of Horizontal DNA Gene Transfer by Extracellular Vesicles

“…showing that SRY (sex-determining region, Y) DNAs in plasma EV from coronary artery disease patients was increased. The authors concluded that EV-associated genomic DNA can be transferred to and expressed in recipient cells, thus influencing the function of the recipient cells by increasing DNA-coding mRNA and protein levels [ 39 ]. These in vivo results together with our in vitro data show that horizontal DNA transfer seems to be a rare but physiological process.…”

Methodological Guidelines to Study Extracellular Vesicles

“…61,167 DNA Although evidence that EVs contain DNA is scant in literature when compared with EV-RNA, an increasing number of studies suggests that under stress, cells release EVs containing DNA that differs from DNA present in apoptotic bodies. [168][169][170][171] As in RNA analysis, next-generation sequencing, PCR, and other methods can be used to analyze or validate the EV-DNA content. Moreover, a DNAse digestion step of intact EVs is needed to demonstrate the presence of intravesicular DNA.…”

Emerging role of exosome-mediated intercellular communication in vascular remodeling

“…The SRY gene-enriched extracellular vesicles contributed to enhanced adherence of monocytes and endothelial cells. In addition, injection of SRY extracellular vesicles into ApoE −/− mice accelerated atherosclerosis, which suggested a potential pathophysiological role of the leukocyte-derived exosomes [40]. …”