Hypericin-mediated sonodynamic therapy induces autophagy and decreases lipids in THP-1 macrophage by promoting ROS-dependent nuclear translocation of TFEB.

Xuesong Li,Liming Yang,Yueqing Jiang,Zhongni Liu,Jing Li,Zhaoyu Zhong,Ye Tian,Wei Wang,Zengxiang Dong,Jiayuan Kou,Longbin Zheng,Xin Zhang,Yajun Zhao,Xiaobo Han

doi:10.1038/cddis.2016.433

Abstract

Lipid catabolism disorder is the primary cause of atherosclerosis. Transcription factor EB (TFEB) prevents atherosclerosis by activating macrophage autophagy to promote lipid degradation. Hypericin-mediated sonodynamic therapy (HY-SDT) has been proved non-invasively inducing THP-1-derived macrophage apoptosis; however, it is unknown whether macrophage autophagy could be triggered by HY-SDT to influence cellular lipid catabolism via regulating TFEB. Here, we report that HY-SDT resulted in the time-dependent THP-1-derived macrophage autophagy activation through AMPK/AKT/mTOR pathway. Besides, TFEB nuclear translocation in macrophage was triggered by HY-SDT to promote autophagy activation and lysosome regeneration which enhanced lipid degradation in response to atherogenic lipid stressors. Moreover, following HY-SDT, the ABCA1 expression level was increased to promote lipid efflux in macrophage, and the expression levels of CD36 and SR-A were decreased to inhibit lipid uptake, both of which were prevented by TFEB knockdown. These results indicated that TFEB nuclear translocation activated by HY-SDT was not only the key regulator of autophagy activation and lysosome regeneration in macrophage to promote lipolysis, but also had a crucial role in reverse cholesterol transporters to decrease lipid uptake and increase lipid efflux. Reactive oxygen species (ROS) were adequately generated in macrophage by HY-SDT. Further, ROS scavenger N-acetyl-l-cysteine abolished HY-SDT-induced TFEB nuclear translocation and autophagy activation, implying that ROS were the primary upstream factors responsible for these effects during HY-SDT. In summary, our data indicate that HY-SDT decreases lipid content in macrophage by promoting ROS-dependent nuclear translocation of TFEB to influence consequent autophagy activation and cholesterol transporters. Thus, HY-SDT may be beneficial for atherosclerosis via TFEB regulation to ameliorate lipid overload in atherosclerotic plaques.

Highlights

Lipid catabolism disorder leads to chronic inflammation of arterial wall and subsequent atherosclerosis.[1]
The results showed that autophagy was activated in the HY-sonodynamic therapy (SDT) group as evidenced by a substantial increase in the number of GFP-LC3 puncta (Figure 1a) as well as the puncta of red fluorescence by acridine orange staining compared with either treatment alone (Supplementary Figure S1)
We explored whether the lipid content reduction was related to the reduced uptake. 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate labeled oxidized low-density lipoprotein (ox-LDL) (DIL-ox-LDL) binding assay showed hypericinmediated SDT (HY-SDT)-decreased lipid uptake of macrophage, which was reversed by NAC and Transcription factor EB (TFEB) siRNA but not ATG5 siRNA and CC (Figure 5e), indicating that the decreased lipid uptake is related to reactive oxygen species (ROS) and TFEB

Summary

Introduction

Lipid catabolism disorder leads to chronic inflammation of arterial wall and subsequent atherosclerosis.[1]. The emerging sonodynamic therapy (SDT) involving the synergistic effects of low-intensity ultrasound and a sonosensitizer was inspired by photodynamic therapy (PDT) and is characterized by dominant tissue penetration, noninvasion and regional focusing.[8] SDT induces the generation of reactive oxygen species (ROS) and apoptosis in tumor cells, and has been shown to greatly improve the outcome of cancer patient by promoting tumor shrinkage while reducing metastases of tumor cells.[9,10,11,12,13] We previously revealed that SDT could effectively induce apoptosis of macrophage and macrophage foam cell via mitochondrial-caspase dependent pathway[14,15] and rapidly stabilize atherosclerotic plaques.[16] SDT possesses high repeatability owing to its relative security and accessibility These advance suggest that SDT could be a promising regimen against atherosclerosis. Our results showed that HY-SDT induced AMPK/AKT/mTOR pathway dependent autophagy and decreased lipid content in macrophage through regulating ROS-dependent TFEB nuclear translocation

Methods

Results

Conclusion