Ochoa Mendoza Valentina, de Oliveira Amanda Almeida, Nunes Kenia Pedrosa
Laboratory of Vascular Biology, Department of Biomedical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA.
Cells. 2025 Mar 13;14(6):424. doi: 10.3390/cells14060424.
Type 2 diabetes (T2D) is a chronic disease that damages blood vessels and increases the risk of cardiovascular disease (CVD). Heat-shock protein 70 (HSP70), a family of chaperone proteins, has been recently reported as a key player in vascular reactivity that affects large blood vessels like the aorta. Hyperglycemia, a hallmark of diabetes, correlates with the severity of vascular damage and circulating HSP70 levels. In diabetes, blood vessels often show impaired contractility, contributing to vascular dysfunction. However, HSP70's specific role in T2D-related vascular contraction remains unclear. We hypothesized that blocking HSP70 would improve vascular function in a widely used diabetic mouse model (db/db). To test this, we measured both vascular intracellular and serum circulating HSP70 levels in control and diabetic male mice using immunofluorescence and Western blotting. We also examined the aorta's contractile response using a wire myograph system, which measured the force produced in response to phenylephrine (PE), both with and without VER155008, a pharmacological inhibitor that targets the ATPase domain of HSP70, and after removing extracellular calcium. Our findings show that intracellular HSP70 (iHSP70) levels were similar in control and diabetic groups, while circulating HSP70 (eHSP70) levels were higher in the serum of diabetic mice, altering the iHSP70/eHSP70 ratio. Even though VER155008 attenuated both phases of the contractile curve in the diabetic and control groups, enhanced vasoconstriction to PE was only observed in the tonic phase of the curve in the db/db group, which was prevented by iHSP70 inhibition. This effect involved calcium mobilization, as both the maximal and total contraction forces to PE were restored in groups treated with VER155008. Additionally, internal calcium levels in aortic rings treated with VER155008 decreased, as observed in force generation upon calcium reintroduction, which was further corroborated using a biochemical calcium assay. In conclusion, our study demonstrates that blocking HSP70 improves vascular reactivity in the hyperglycemic state of T2D by restoring proper vascular contraction.
2型糖尿病（T2D）是一种会损害血管并增加心血管疾病（CVD）风险的慢性疾病。热休克蛋白70（HSP70）是一类伴侣蛋白，最近有报道称它是影响主动脉等大血管的血管反应性的关键因素。高血糖是糖尿病的一个标志，与血管损伤的严重程度和循环HSP70水平相关。在糖尿病中，血管通常表现出收缩功能受损，导致血管功能障碍。然而，HSP70在T2D相关血管收缩中的具体作用仍不清楚。我们假设在广泛使用的糖尿病小鼠模型（db/db）中阻断HSP70会改善血管功能。为了验证这一点，我们使用免疫荧光和蛋白质印迹法测量了对照和糖尿病雄性小鼠血管内细胞和血清中循环HSP70的水平。我们还使用线肌张力测定系统检查了主动脉的收缩反应，该系统测量了对去氧肾上腺素（PE）产生的力，分别在有和没有VER155008（一种靶向HSP70 ATP酶结构域的药理抑制剂）的情况下，以及在去除细胞外钙之后。我们的研究结果表明，对照和糖尿病组的细胞内HSP70（iHSP70）水平相似，而糖尿病小鼠血清中的循环HSP70（eHSP70）水平较高，改变了iHSP70/eHSP70的比值。尽管VER155008减弱了糖尿病组和对照组收缩曲线的两个阶段，但仅在db/db组曲线的强直期观察到对PE的血管收缩增强，而iHSP70抑制可防止这种情况。这种作用涉及钙动员，因为在用VER155008治疗的组中，对PE的最大和总收缩力都恢复了。此外，在用VER155008处理的主动脉环中，内部钙水平降低，这在重新引入钙时观察到的力产生中得到了体现，使用生化钙测定法进一步证实了这一点。总之，我们的研究表明，阻断HSP70可通过恢复适当的血管收缩来改善T2D高血糖状态下的血管反应性。
