HUVEC;Human Umbilical Vein Endothelial Cells

Interaction between PS-NPs and Human Umbilical Vein Endothelial Cells

Nanoplastics (NPs) are ubiquitous in the environment and can enter the human body by different routes of exposure, which may potentially lead to adverse health effects. In this study, Lu's team explored the interaction and autophagy of polystyrene nanoplastics (PS-NPs) (100 and 500 nm) on human umbilical vein endothelial cells (HUVECs). The autophagic flux level in PS-NPs–treated HUVECs was assessed using a dual fluorescent LC3 lentiviral reporter assay.

Interaction of PS-NPs with target cells is pivotal for their toxicity. The flow cytometry assay showed that 100 nm PS-NPs could be taken up by almost all the HUVECs at 5-25 μg/mL and were accumulated in a time-dependent manner (Fig. 1A-B). Similar interactions were observed in HUVECs with 500 nm PS-NPs (Fig.1C-D). Moreover, both 100 and 500 nm PS-NPs (10/25 μg/mL) increased the cells' fluorescence intensity significantly within 10 min (Fig. 1E-F). The fluorescence intensity was positively correlated with PS-NPs' concentration and lasted in a sustained manner for 10 min-3 h (Fig. 1E-F). These data indicated that PS-NPs interacted with HUVECs in a time- and concentration-dependent manner.

Fig. 1. The effect of exposure time and concentration on PS-NPs internalization in HUVECs (Lu Y Y, Li H Y, et al., 2022).

Activation of Piezo1 by Ultrasonic Stimulation and Its Effect on The Permeability of Human Umbilical Vein Endothelial Cells

Ultrasound produces acoustic radiation forces which generate shear stress in the acoustic field. Shear stress can be sensed by a mechanosensitive ion channel protein Piezo1 and transduced into downstream signalling. In this study, Zhang's team employed ultrasonic stimulation to investigate Piezo1 sensitivity and its downstream biological functions in human umbilical vein endothelial cells (HUVECs).

To understand the impact of ultrasonic stimulation on Piezo1, HUVECs were transfected with Piezo1 siRNA or negative control siRNA, and they were named as CP1.si and CNc.si cells, respectively. RT-qPCR and Western blot showed that Piezo1 was effectively knocked down in CP1.si cells (Fig. 2a, b). To identify optimal ultrasonic stimulation parameters, CBlank cells with endogenous Piezo1 were stimulated with 1 W or 0.2 W ultrasound for 10 s, and then calcium fluorescence imaging was performed. As shown in Fig. 3, 1 W and 0.2 W ultrasound both led to a significant increase in intracellular calcium. However, 1 W ultrasound damaged cells (Fig. 3b). Thus, 0.2 W was determined as the appropriate power.

Fig. 2. (a) Relative expression of Piezo1 analyzed using real-time PCR; (b) Expression of Piezo1 analyzed using Western blotting (Zhang L G, Liu X J, et al., 2020).

Fig. 3. Calcium fluorescent images of C_Blank subjected to ultrasound stimulation at 1 W and 0.2 W (Zhang L G, Liu X J, et al., 2020).