Caveolin 1-related autophagy initiated by aldosterone-induced oxidation promotes liver sinusoidal endothelial cells defenestration

Abstract

Aldosterone, with pro-oxidation and pro-autophagy capabilities, plays a key role in liver fibrosis. However, the mechanisms underlying aldosterone-promoted liver sinusoidal endothelial cells (LSECs) defenestration remain unknown. Caveolin 1 (Cav1) displays close links with autophagy and fenestration. Hence, we aim to investigate the role of Cav1-related autophagy in LSECs defenestration. We found the increase of aldosterone/MR (mineralocorticoid receptor) level, oxidation, autophagy, and defenestration in LSECs in the human fibrotic liver, BDL or hyperaldosteronism models; while antagonizing aldosterone or inhibiting autophagy relieved LSECs defenestration in BDL-induced fibrosis or hyperaldosteronism models. In vitro, fenestrae of primary LSECs gradually shrank, along with the down-regulation of the NO-dependent pathway and the augment of the AMPK-dependent autophagy; these effects were aggravated by rapamycin (an autophagy activator) or aldosterone treatment. Additionally, aldosterone increased oxidation mediated by Cav1, reduced ATP generation, and subsequently induced the AMPK-dependent autophagy, leading to the down-regulation of the NO-dependent pathway and LSECs defenestration. These effects were reversed by MR antagonist spironolactone, antioxidants or autophagy inhibitors. Besides, aldosterone enhanced the co-immunoprecipitation of Cav1 with p62 and ubiquitin, and induced Cav1 co-immunofluorescence staining with LC3, ubiquitin, and F-actin in the perinuclear area of LSECs. Furthermore, aldosterone treatment increased the membrane protein level of Cav1, whereas decrease the cytoplasmic protein level of Cav1, indicating that aldosterone induced Cav1-related selective autophagy and F-actin remodeling to promote defenestration. Consequently, Cav1-related selective autophagy initiated by aldosterone-induced oxidation promotes LSECs defenestration via activating the AMPK-ULK1 pathway and inhibiting the NO-dependent pathway.

The Reactive Oxygen Species–Mitophagy Signaling Pathway Regulates Liver Endothelial Cell Survival During Ischemia/Reperfusion Injury

“…These studies suggest that failure to reactivate autophagy during reperfusion by activating KLF2 may regulate the increased cell death in LEC and is associated with microvascular dysfunction . It remains to be determined whether KLF2 activation is ROS‐dependent in LEC or whether alternative signaling pathways such as transcription factor EB, adenosine monophosphate–activated protein kinase, hypoxia inducible factor 1, and FOXO can also regulate LEC autophagy. Overall, our findings suggest that the early injury to LEC during IRI is linked to a disruption in the autophagy‐signaling pathway …”

SIRT1 ameliorates premature senescence-induced defenestration in hepatic sinusoidal endothelial cell

“…The contraction and dilatation of fenestrae in HSECs and its differentiation are regulated by actin cytoskeleton (including F-actin) [4]. Our previous studies reveal that oxidative stress facilitates defenestration in HSECs via F-actin remodeling in liver fibrogenesis [5,6]. Novel findings show that lamins and their associated proteins, which regulate nucleoskeleton and cytoskeleton, affect cellular differentiation and senescence [7,8].…”

“…Primary rat HSECs were isolated from normal male SD rats and identified by SEM, based on the modified method [5,6]. Primary rat HSECs were cultured in plates with medium comprising 80% MCDB131 (Gibco, 10372019) and 20% fetal bovine serum (FBS, Biological Industries, 04-007-1A).…”

“…The liver tissue of the model rats and primary rat HSECs were fixed with 2.5% glutaldehyde and subsequently dehydrated and then coated with gold using the coating apparatus, based on the modified method [5]. Eventually, fenestrae in primary rat HSECs of samples were observed with SEM at 15-kV acceleration voltage.…”

“…Primary rat HSECs were transfected with SIRT1 adenovirus vectors, and were subsequently stimulated with H 2 O 2 for 2 days. IP and immunoblotting (IB) were performed as previously described [5]. The antibodies for IP included anti-progerin and non-specific IgG; the antibodies for IB included anti-progerin, anti-Ac p53 K381, and anti-p53.…”