Lyso-globotriaosylsphingosine induces endothelial dysfunction via autophagy-dependent regulation of necroptosis

by Selleckchem | Aug 05 2023

Fabry disease is a lysosomal storage disorder characterized by the lysosomal accumulations of glycosphingolipids in a variety of cytotypes, which include endothelial cells. The disease is inherited and originates from an error in glycosphingolipid catabolism caused by insufficient α-galactosidase A activity, which causes uncontrolled progressive storage of intracellular globotriaosylceramide (Gb3) in the vasculature and extracellular accumulation of lyso-Gb3 (a deacetylated soluble form of Gb3). Necrosis can lead to inflammation, which exacerbates necrosis and creates a positive feedback loop that triggers necroinflammation. However, the role played by necroptosis, a form of programmed necrotic cell death, in the cell-to-cell inflammatory reaction between epithelial and endothelial cells is unclear. Thus, the present study was undertaken to determine whether lyso-Gb3 induces necroptosis and whether necroptosis inhibition protects endothelial dysfunction against lyso-Gb3 inflamed retinal pigment epithelial cells. We found lyso-Gb3 induced necroptosis of a retinal pigment epithelial cell line (ARPE-19) in an autophagy-dependent manner and that conditioned media (CM) from ARPE-19 cells treated with lyso-Gb3 induced the necroptosis, inflammation, and senescence of human umbilical vein endothelial cells. In addition, a pharmacological study showed CM from lyso-Gb3 treated ARPE-19 cells induced endothelial necroptosis, inflammation, and senescence were significantly inhibited by an autophagy inhibitor (3-MA) and by two necroptosis inhibitors (necrostatin and GSK-872), respectively. These results demonstrate lyso-Gb3 induces necroptosis via autophagy and suggest that lyso-Gb3 inflamed retinal pigment epithelial cells trigger endothelial dysfunction via the autophagy-dependent necroptosis pathway. This study suggests the involvement of a novel autophagy-dependent necroptosis pathway in the regulation of endothelial dysfunction in Fabry disease.

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Fabry disease is a rare genetic disorder that affects lysosomal function, leading to the accumulation of glycosphingolipids, particularly globotriaosylceramide (Gb3), within various cell types, including endothelial cells. This accumulation is caused by a deficiency in the enzyme α-galactosidase A, which is responsible for breaking down Gb3. The buildup of Gb3 and its deacetylated soluble form, lyso-Gb3, results in cellular damage and dysfunction.

In the context of Fabry disease, necrosis, a form of cell death, can occur, leading to inflammation. This inflammation, in turn, exacerbates necrosis, creating a positive feedback loop that contributes to a process known as necroinflammation. However, the specific role of necroptosis, a type of programmed necrotic cell death, in the inflammatory reaction between epithelial and endothelial cells is not well understood.

To address this question, a study was conducted to investigate whether lyso-Gb3 induces necroptosis and if inhibiting necroptosis could protect against endothelial dysfunction caused by lyso-Gb3 in inflamed retinal pigment epithelial cells. The researchers used a retinal pigment epithelial cell line (ARPE-19) and found that lyso-Gb3 triggered necroptosis in these cells, and this process was dependent on autophagy, a cellular recycling mechanism.

Moreover, the conditioned media (CM) obtained from lyso-Gb3-treated ARPE-19 cells induced necroptosis, inflammation, and senescence (cellular aging) in human umbilical vein endothelial cells. The researchers also conducted pharmacological experiments and observed that inhibiting autophagy with 3-methyladenine (3-MA) and inhibiting necroptosis with necrostatin and GSK-872 significantly reduced endothelial necroptosis, inflammation, and senescence induced by CM from lyso-Gb3-treated ARPE-19 cells.

In summary, the study demonstrated that lyso-Gb3 induces necroptosis in retinal pigment epithelial cells through an autophagy-dependent mechanism. The results also suggest that lyso-Gb3-inflamed retinal pigment epithelial cells contribute to endothelial dysfunction by triggering necroptosis in endothelial cells via an autophagy-dependent pathway. This study sheds light on a potential novel pathway involving autophagy-dependent necroptosis in the regulation of endothelial dysfunction in Fabry disease.