Augmented contractility of murine femoral arteries in a streptozotocin diabetes model is related to increased phosphorylation of MYPT1. Issue 3 (10th February 2019)

• Record Type: Journal Article
• Authors: Lubomirov, Lubomir T.; Gagov, Hristo; Schroeter, Mechthild M.; Wiesner, Rudolf J.; Franko, Andras
• Is Part Of: Physiological reports. Volume 7:Issue 3(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-02-10
• Subjects: MYPT1 phosphorylation -- streptozotocin‐induced diabetes -- vascular tone; Physiology -- Periodicals; 571
• DOI: 10.14814/phy2.13975
• Languages: English
• ISSNs: 2051-817X

Abstract

Abstract: Diabetes mellitus (DM) is a metabolic disorder with high prevalence, and a major risk factor for macro‐ and microvascular abnormalities. This study was undertaken to explore the mechanisms of hypercontractility of murine femoral arteries (FA) obtained from mice with streptozotocin (STZ)‐induced diabetes and its relation to the phosphorylation profile of the myosin phosphatase target subunit 1, MYPT1. The immunoreactivity of MYPT1 toward phospho‐MYPT1‐T696, MYPT1‐T853, or MYPT1‐S695, used as a read out for MYPT1 phosphorylation, has been studied by Western Blotting. Contractile activity of FA from control and STZ mice has been studied by wire myography. At basal conditions (no treatment), the immunoreactivity of MYPT1‐T696/T853 was ~2‐fold higher in the STZ arteries compared with controls. No changes in MYPT1‐T696/853 phosphorylation were observed after stimulation with the Thromboxan‐A2 analog, U46619. Neither basal nor U46619‐stimulated phosphorylation of MYPT1 at S695 was affected by STZ treatment. Mechanical distensibility and basal tone of FA obtained from STZ animals were similar to controls. Maximal force after treatment of FA with the contractile agonists phenylephrine (10 μ mol/L) or U46619 (1 μ mol/L) was augmented in the arteries of STZ mice by ~2‐ and ~1.5‐fold, respectively. In summary, our study suggests that development of a hypercontractile phenotype in murine FA in STZ diabetes is at least partially related to an increase in phosphorylation of MLCP at MYPT1‐T696/853. Interestingly, the phosphorylation at S695 site was not altered in STZ‐induced diabetes, supporting the view that S695 may serve as a sensor for mechanical activity which is not directly involved in tone regulation. Abstract : Our study supports the view that augmented contractility of murine femoral arteries in Streptozotocin‐induced diabetes is related to an increase in phosphorylation of Myosin Phosphatase Target subunit 1 (MYPT1) at Threonine 696 and 853. The study highlights the potential importance of the inhibitory threonine phosphorylation of MYPT1 for the development of an abnormal vascular phenotype in the progression of diabetes mellitus.