Brayer Mallory, Zderic Vesna, Jeremic Aleksandar
Department of Biological Science, The George Washington University, Washington, DC, USA.
Department of Biomedical Engineering, The George Washington University, Washington, DC, USA.
J Ultrasound Med. 2025 Sep;44(9):1577-1593. doi: 10.1002/jum.16712. Epub 2025 May 1.
Type 2 diabetes is partially caused by insufficient pancreatic β cell insulin secretion. Previous studies show therapeutic ultrasound (TUS) evokes insulin secretion from β cells as a potential treatment for type 2 diabetes; however, how β cells sense TUS and the broad effects of this treatment on cells remain unknown. Here, we identified mechanosensitive channels (MSC) expressed by β cells and TUS-mediated gene downregulation and reactive oxygen species (ROS) formation.
For all experiments, 1 W/cm intensity and 800 kHz frequency TUS were continuously applied for 5 minutes with a 100% duty cycle. RNA and protein isolation of human pancreatic islets and the rat insulinoma INS 832/13 cell line were used for rtqPCR and western blot, respectively, to determine MSC expression. INS cells treated with MSC agonists and/or antagonists during TUS were visualized via fluorescent microscopy to track ROS formation. Using the same treatments, rtPCR analysis of INS insulin and IAPP encoding insulin and islet amyloid polypeptide (IAPP), respectively, was performed. TUS treatments were replicated in rats from which pancreatic sections were collected for immunohistochemistry analysis.
We found the expression of TRPV2, TRPV5, and piezo1 in human islets and INS cells. TUS increased ROS formation in INS cells compared to sham-treated controls (P < .0001); however, modulation of MSC mitigated this effect (P < .001). TUS decreased the expression of the genes insulin and IAPP in INS cells compared to sham-treated controls (P < .001 and P < .01, respectively); however, complete MSC inhibition reversed this effect (P < .01 and P < .05, respectively). In our rat model, pancreatic and duodenal homeobox 1 (PDX1) expression was decreased by TUS compared to sham-treated controls (*P < .05); however, TUS did not decrease insulin or IAPP levels (P > .05).
We report the expression of TRPV2, TRPV5, and piezo1 in human and rodent pancreatic β cells that are implicated in both TUS-mediated ROS formation and the downregulation of essential β cell genes.
2型糖尿病部分是由胰腺β细胞胰岛素分泌不足引起的。先前的研究表明，治疗性超声（TUS）可促使β细胞分泌胰岛素，作为2型糖尿病的一种潜在治疗方法；然而，β细胞如何感知TUS以及这种治疗对细胞的广泛影响仍不清楚。在此，我们鉴定了β细胞表达的机械敏感通道（MSC）以及TUS介导的基因下调和活性氧（ROS）形成。
在所有实验中，以1W/cm的强度和800kHz的频率持续施加TUS 5分钟，占空比为100%。分别用人胰岛和大鼠胰岛素瘤INS 832/13细胞系的RNA和蛋白质进行逆转录定量聚合酶链反应（rtqPCR）和蛋白质免疫印迹分析，以确定MSC的表达。在TUS期间用MSC激动剂和/或拮抗剂处理的INS细胞通过荧光显微镜观察以追踪ROS的形成。使用相同的处理方法，分别对INS胰岛素和编码胰岛素及胰岛淀粉样多肽（IAPP）的IAPP进行逆转录聚合酶链反应（rtPCR）分析。在大鼠中重复TUS处理，收集胰腺切片进行免疫组织化学分析。
我们发现TRPV2、TRPV5和piezo1在人胰岛和INS细胞中表达。与假处理对照组相比，TUS增加了INS细胞中ROS的形成（P <.0001）；然而，对MSC的调节减轻了这种作用（P <.001）。与假处理对照组相比，TUS降低了INS细胞中胰岛素和IAPP基因的表达（分别为P <.001和P <.01）；然而，完全抑制MSC可逆转这种作用（分别为P <.01和P <.05）。在我们的大鼠模型中，与假处理对照组相比，TUS降低了胰腺和十二指肠同源盒1（PDX1）的表达（*P <.05）；然而，TUS并未降低胰岛素或IAPP水平（P >.05）。
我们报道了TRPV2、TRPV5和piezo1在人和啮齿动物胰腺β细胞中的表达，它们与TUS介导的ROS形成和β细胞必需基因的下调有关。
