Unbalanced Redox With Autophagy in Cardiovascular Disease

Homocysteine metabolites impair the PHF8/H4K20me1/mTOR/autophagy pathway by upregulating the expression of histone demethylase PHF8-targeting microRNAs in human vascular endothelial cells and mice

The inability to efficiently metabolize homocysteine (Hcy) due to nutritional and genetic deficiencies, leads to hyperhomocysteinemia (HHcy) and endothelial dysfunction, a hallmark of atherosclerosis which underpins cardiovascular disease (CVD). PHF8 is a histone demethylase that demethylates H4K20me1, which affects the mammalian target of rapamycin (mTOR) signaling and autophagy, processes that play important roles in CVD. PHF8 is regulated by microRNA (miR) such as miR-22-3p and miR-1229-3p. Biochemically, HHcy is characterized by elevated levels of Hcy, Hcy-thiolactone and N-Hcy-protein. Here, we examined the effects of these metabolites on miR-22-3p, miR-1229-3p, and their target PHF8, as well as on the downstream consequences of these effects on H4K20me1, mTOR-, and autophagy-related proteins and mRNAs expression in human umbilical vein endothelial cells (HUVEC). We found that treatments with N-Hcy-protein, Hcy-thiolactone, or Hcy upregulated miR-22-3p and miR-1229-3p, attenuated PHF8 expression, upregulated H4K20me1, mTOR, and phospho-mTOR. Autophagy-related proteins (BECN1, ATG5, ATG7, lipidated LC3-II, and LC3-II/LC3-I ratio) were significantly downregulated by at least one of these metabolites. We also found similar changes in the expression of miR-22-3p, Phf8, mTOR- and autophagy-related proteins/mRNAs in vivo in hearts of Cbs-/- mice, which show severe HHcy and endothelial dysfunction. Treatments with inhibitors of miR-22-3p or miR-1229-3p abrogated the effects of Hcy-thiolactone, N-Hcy-protein, and Hcy on miR expression and on PHF8, H4K20me1, mTOR-, and autophagy-related proteins/mRNAs in HUVEC. Taken together, these findings show that Hcy metabolites upregulate miR-22-3p and miR-1229-3p expression, which then dysregulate the PHF8/H4K20me1/mTOR/autophagy pathway, important for vascular homeostasis.

Homocysteine metabolites inhibit autophagy by upregulating miR-21-5p, miR-155-5p, miR-216-5p, and miR-320c-3p in human vascular endothelial cells

Nutritional and genetic deficiencies in homocysteine (Hcy) metabolism lead to hyperhomocysteinemia (HHcy) and cause endothelial dysfunction, a hallmark of atherosclerosis, which is a major cause of cardiovascular disease (CVD). Impaired autophagy causes the accumulation of damaged proteins and organelles and is associated with CVD. Biochemically, HHcy is characterized by elevated levels of Hcy and its metabolites, Hcy-thiolactone and N-Hcy-protein. However, whether these metabolites can dysregulate mTOR signaling and autophagy in endothelial cells is not known. Here, we examined the influence of Hcy-thiolactone, N-Hcy-protein, and Hcy on autophagy human umbilical vein endothelial cells. We found that treatments with Hcy-thiolactone, N-Hcy-protein, or Hcy significantly downregulated beclin 1 (BECN1), autophagy-related 5 (ATG5), autophagy-related 7 (ATG7), and microtubule-associated protein 1 light chain 3 (LC3) mRNA and protein levels. We also found that these changes were mediated by upregulation by Hcy-thiolactone, N-Hcy-protein, and Hcy of autophagy-targeting microRNA (miR): miR-21, miR-155, miR-216, and miR-320c. The effects of these metabolites on levels of miR targeting autophagy as well as on the levels of BECN1, ATG5, ATG7, and LC3 mRNA and protein were abrogated by treatments with inhibitors of miR-21, miR-155, miR-216, and mir320c. Taken together, our findings show that Hcy metabolites can upregulate miR-21, miR-155, miR-216, and mir320c, which then downregulate autophagy in human endothelial cells, important for vascular homeostasis.

An Emerging Role of Micro- and Nanoplastics in Vascular Diseases

Vascular diseases are the leading causes of death worldwide, and they are attributable to multiple pathologies, such as atherosclerosis, diabetes, and chronic obstructive pulmonary disease. Exposure to various environmental contaminants is associated with the development of various diseases, including vascular diseases. Among environmental contaminants, micro- and nanoplastics have gained attention as global environmental risk factors that threaten human health. Recently, extensive research has been conducted on the effects of micro- and nanoplastics on various human diseases, including vascular diseases. In this review, we highlight the effects of micro- and nanoplastics on vascular diseases.

Atorvastatin's Therapeutic Potential in Atherosclerosis: Inhibiting TGF-β-Induced Proteoglycan Glycosaminoglycan Chain Elongation through ROS-ERK1/2-Smad2L Signaling Pathway Modulation in Vascular Smooth Muscle Cells

OBJECTIVE

According to the response-to-retention hypothesis, the inception of atherosclerosis is attributed to the deposition and retention of lipoprotein in the arterial intima, facilitated by altered proteoglycans with hyperelongated glycosaminoglycan (GAG) chains. Recent studies have elucidated a signaling pathway whereby transforming growth factor-β (TGF-β) promotes the expression of genes linked to proteoglycan GAG chain elongation (CHSY1 and CHST11) via reactive oxygen species (ROS) and the downstream phosphorylation of ERK1/2 and Smad2L. Atorvastatin is known to exhibit pleiotropic effects, including antioxidant and anti-inflammatory. The purpose of the present research was to ascertain the influence of atorvastatin on TGF-β-stimulated expression of CHSY1 and CHST11 and associated signaling pathways using an in vitro model.

MATERIALS AND METHODS

In this experimental study, vascular smooth muscle cells (VSMCs) were pre-incubated with atorvastatin (0.1-10 μM) prior to being stimulated with TGF-β (2 ng/ml). The experiment aimed to evaluate the phosphorylation levels of Smad2C, Smad2L, ERK1/2, the NOX p47phox subunit, ROS production, and the mRNA expression of CHST11 and CHSY1.

RESULTS

Our research results indicated that atorvastatin inhibited TGF-β-stimulated CHSY1 and CHST11 mRNA expression. Further experiments showed that atorvastatin diminished TGF-β-stimulated ROS production and weakened TGF-β-stimulated phosphorylation of p47phox, ERK1/2, and Smad2L; however, we observed no effect on the TGF-β- Smad2C pathway.

CONCLUSION

These data suggest that atorvastatin demonstrates anti-atherogenic properties through the modulation of the ROS-ERK1/2-Smad2L signaling pathway. This provides valuable insight into the potential mechanisms by which atorvastatin exerts its pleiotropic effects against atherosclerosis.