Overexpression of sFlt-1 represses ox-LDL-induced injury of HUVECs by activating autophagy via PI3K/AKT/mTOR pathway

SPAG5 deficiency activates autophagy to reduce atherosclerotic plaque formation in ApoE-/- mice

BACKGROUND

Autophagy, as a regulator of cell survival, plays an important role in atherosclerosis (AS). Sperm associated antigen 5 (SPAG5) is closely associated with the classical autophagy pathway, PI3K/Akt/mTOR signaling pathway. This work attempted to investigate whether SPAG5 can affect AS development by regulating autophagy.

METHODS

Human umbilical vein endothelial cells (HUVECs) were treated with oxidized-low density lipoprotein (ox-LDL) to induce cell damage. ApoE-/- mice were fed a Western diet to establish an AS mouse model. Haematoxylin and eosin (H&E) staining and Oil Red O staining evaluated the pathological changes and in lipid deposition in aortic tissues. CCK-8 and flow cytometry detected cell proliferation and apoptosis. Immunohistochemistry, Enzyme linked immunosorbent assay, qRT-PCR and western blotting assessed the levels of mRNA and proteins.

RESULTS

Ox-LDL treatment elevated SPAG5 expression and the expression of autophagy-related proteins, LC3-I, LC3-II, Beclin-1, and p62, in HUVECs. GFP-LC3 dots were increased in ox-LDL-treated HUVECs and LPS-treated HUVECs. SPAG5 knockdown reversed both ox-LDL and LPS treatment-mediated inhibition of cell proliferation and promotion of apoptosis in HUVECs. SPAG5 silencing further elevated autophagy and repressed the expression of PI3K, p-Akt/Akt, and p-mTOR/mTOR in ox-LDL-treated HUVECs. 3-MA (autophagy inhibitor) treatment reversed SPAG5 silencing-mediated increase of cell proliferation and decrease of apoptosis in ox-LDL-treated HUVECs. In vivo, SPAG5 knockdown reduced atherosclerotic plaques in AS mice through activating autophagy and inhibiting PI3K/Akt/mTOR signaling pathway.

CONCLUSION

This work demonstrated that SPAG5 knockdown alleviated AS development through activating autophagy. Thus, SPAG5 may be a potential target for AS therapy.

Molecular regulation and therapeutic implications of cell death in pulmonary hypertension

Pulmonary hypertension (PH) is a clinical and pathophysiological syndrome caused by changes in pulmonary vascular structure or function that results in increased pulmonary vascular resistance and pulmonary arterial pressure, and it is characterized by pulmonary endothelial dysfunction, pulmonary artery media thickening, pulmonary vascular remodeling, and right ventricular hypertrophy, all of which are driven by an imbalance between the growth and death of pulmonary vascular cells. Programmed cell death (PCD), different from cell necrosis, is an active cellular death mechanism that is activated in response to both internal and external factors and is precisely regulated by cells. More than a dozen PCD modes have been identified, among which apoptosis, autophagy, pyroptosis, ferroptosis, necroptosis, and cuproptosis have been proven to be involved in the pathophysiology of PH to varying degrees. This article provides a summary of the regulatory patterns of different PCD modes and their potential effects on PH. Additionally, it describes the current understanding of this complex and interconnected process and analyzes the therapeutic potential of targeting specific PCD modes as molecular targets.

Natural compounds from botanical drugs targeting mTOR signaling pathway as promising therapeutics for atherosclerosis: A review

Atherosclerosis (AS) is a chronic inflammatory disease that is a major cause of cardiovascular diseases (CVDs), including coronary artery disease, hypertension, myocardial infarction, and heart failure. Hence, the mechanisms of AS are still being explored. A growing compendium of evidence supports that the activity of the mechanistic/mammalian target of rapamycin (mTOR) is highly correlated with the risk of AS. The mTOR signaling pathway contributes to AS progression by regulating autophagy, cell senescence, immune response, and lipid metabolism. Various botanical drugs and their functional compounds have been found to exert anti- AS effects by modulating the activity of the mTOR signaling pathway. In this review, we summarize the pathogenesis of AS based on the mTOR signaling pathway from the aspects of immune response, autophagy, cell senescence, and lipid metabolism, and comb the recent advances in natural compounds from botanical drugs to inhibit the mTOR signaling pathway and delay AS development. This review will provide a new perspective on the mechanisms and precision treatments of AS.

Study on the regulatory effect of leech peptide HE-D on macrophages in atherosclerosis by transcriptome sequencing

ETHNOPHARMACOLOGICAL RELEVANCE

The incidence of atherosclerotic cardiovascular disease is a serious threat to human health. Leeches are used in traditional Chinese medicine to treat cardiovascular diseases. HE-D is an active peptide extracted and isolated from leeches, which can inhibit the migration of RAW264.7 macrophages.

AIM

This study shows the effects of HE-D on macrophages in atherosclerosis and the mechanism of inhibition on the migration of macrophages based on transcriptome sequencing (RNA-Seq).

MATERIALS AND METHODS

The transwell method was used to detect the activity of HE-D in inhibiting the migration of macrophages. Macrophages were divided into control group, lipopolysaccharide group, and HE-D group. Samples were collected and RNA-Seq performed. The DEseq2 method detected significantly differentially expressed genes (DEGs), GO and KEGG Pathway databases were used to analyze the functions and pathway enrichment of DEGs. Finally, qRT-PCR and Western blotting were used to verify the genes screened by RNA-Seq analyses.

RESULTS

Cell experiments showed that HE-D can inhibit the migration of RAW264.7 macrophages induced by LPS. DEseq2 analyses showed that there were 363 DEGs after HE-D administration in the result of RNA-Seq. The GO function of DEGs was significantly enriched in cell migration and inflammation, and the DEGs related to cell migration were significantly enriched in the NF-κB signaling pathway. qRT-PCR and Western blot analyses, showed that when compared with the LPS group, the related genes IKKα, IKKγ, TRAF6, TLR4, and TRAF5 in the NF-κB pathway were significantly down-regulated in the HE-D group. In addition, it was found that the inflammatory factors iNOS and TNF-α were significantly down-regulated, and Arg-1 and IL-10 were up-regulated.

CONCLUSION

HE-D can inhibit the migration of macrophages by inhibiting IKKα and IKKγ in the NF-κB signaling pathway, and promote the transformation of macrophages from M1to M2 subtypes. Therefore, HE-D can potentially be used as a drug for the treatment of atherosclerosis.

BAG3 Alleviates Atherosclerosis by Inhibiting Endothelial-to-Mesenchymal Transition via Autophagy Activation

Atherosclerosis is a chronic systemic inflammatory disease that causes severe cardiovascular events. B cell lymphoma 2-associated athanogene (BAG3) was proven to participate in the regulation of tumor angiogenesis, neurodegenerative diseases, and cardiac diseases, but its role in atherosclerosis remains unclear. Here, we aim to investigate the role of BAG3 in atherosclerosis and elucidate the potential molecular mechanism. In this study, ApoE^-/- mice were given a tail-vein injection of BAG3-overexpressing lentivirus and fed a 12-week high-fat diet (HFD) to investigate the role of BAG3 in atherosclerosis. The overexpression of BAG3 reduced plaque areas and improved atherosclerosis in ApoE^-/- mice. Our research proves that BAG3 promotes autophagy in vitro, contributing to the suppression of EndMT in human umbilical vein endothelial cells (HUVECs). Mechanically, autophagy activation is mediated by BAG3 via the interaction between BAG3 and its chaperones HSP70 and HSPB8. In conclusion, BAG3 facilitates autophagy activation via the formation of the chaperone-assisted selective autophagy (CASA) complex interacting with HSP70 and HSPB8, leading to the inhibition of EndMT during the progression of atherosclerosis and indicating that BAG3 is a potential therapeutic target for atherosclerosis.

Ibandronate promotes autophagy by inhibiting Rac1–mTOR signaling pathway in vitro and in vivo

We previously reported that ibandronate (IBAN) could improve endothelial function in spontaneously hypertensive rats. However, the mechanism by which IBAN improves endothelial function is unclear. The IBAN-induced autophagic process in vitro experiments were determined by detection of LC3, Beclin1, and P62 protein levels via western blotting. The autophagy flux was detected by confocal microscopy and transmission electron microscopy. For in vivo experiments, spontaneously hypertensive rats were orally administered with IBAN. Utilizing angiotensin II (Ang II) to stimulate the human umbilical vein endothelial cells (HUVECs) and human pulmonary microvascular endothelial cells (HPMECs) as a model of endothelial cell injury in hypertension, we found that IBAN promoted autophagy and protected cell viability in Ang II-treated-endothelial cells while these effects could be reversed by autophagy inhibitor. In terms of mechanism, IBAN treatment decreased the levels of Rac1 and mammalian target of rapamycin (mTOR) pathway. Activating either Rac1 or mTOR could reverse IBAN-induced autophagy. Furthermore, the in vivo experiments also indicated that IBAN promotes autophagy by downregulating Rac1-mTOR. Taken together, our results firstly revealed that IBAN enhances autophagy via inhibiting Rac1-mTOR signaling pathway, and thus alleviates Ang II-induced injury in endothelial cells.