Nitric oxide and prostanoids in early- and late-stages of liver sinusoidal endothelial cells (LSECs) dysfunction in non-alcoholic fatty liver disease (NAFLD)

Keywords: LSECs dysfunction, NAFLD, prostanoids, metabolismLSECs dysfunction, manifested structurally by defenestration and biochemically by impairment of nitric oxide (NO) production, is regarded as a key event in multiple... [ view full abstract ]

Keywords: LSECs dysfunction, NAFLD, prostanoids, metabolism

LSECs dysfunction, manifested structurally by defenestration and biochemically by impairment of nitric oxide (NO) production, is regarded as a key event in multiple liver disorders including NAFLD.

The aim of this work was to study changes in NO and prostanoids production, pro-inflammatory markers, LSECs metabolism and porosity at early- and late-stages of NAFLD progression.

The phenotype of LSECs was determined at 2 and 20 weeks of high fat diet (HFD) feeding in primary LSECs isolated from C57BL/6 mice. The LSECs phenotype was characterized in vitro by expression of biochemical markers (immunostaining, RT-qPCR), secreted prostanoids (LC/MS/MS technique), porosity (SEM) and bioenergetics (Seahorse XFe96 Analyzer). Functional studies were performed in ex vivo isolated liver (NO, PGI₂).

The early LSECs changes at 2 weeks of HFD involved increased expression of E-selectin, ICAM-1, VCAM-1 and compensatory increase in NOS3 expression and production of PGD₂, PGE₂ and PGI₂. Additionally, impaired mitochondrial respiration was observed along with increased number of LSECs with shrunk cytoplasm and surprisingly increased porosity in remaining LSECs. In turn, at 20 weeks of HFD overexpression of adhesion molecules, was associated with LSECs partial defenestration with no differences in mitochondrial respiration and glycolysis.

At early stage of NAFLD, biochemical, functional and metabolic alterations in LSECs suggest the phenotype of LSECs dysfunction, which however, was not associated with significant LSECs defenestration until late phase of NAFLD possibly due to compensatory overproduction of PGI₂ and  PGD₂.

Acknowledgment: This work was supported by National Science Centre grant No DEC-2015/16/W/NZ4/00070.