Fructose-1,6-bisphosphate reverts iron-induced phenotype of hepatic stellate cells by chelating ferrous ions

Abstract

Hepatic fibrosis is an extracellular matrix deposition by hepatic stellate cells (HSC). Fibrosis can be caused by iron, which will lead to hydroxyl radical production and cell damage. Fructose-1,6-bisphosphate (FBP) has been shown to deliver therapeutic effects in many pathological situations. In this work, we aimed to test the effects of FBP in HSC cell line, GRX, exposed to an excess of iron (Fe). The Fe-treatment increased cell proliferation and FBP reversed this effect, which was not due to increased necrosis, apoptosis or changes in cell cycle. Oil Red-O staining showed that FBP successfully increased lipid content and lead GRX cells to present characteristics of quiescent HSC. Fe-treatment decreased PPAR-γ expression and increased Col-1 expression. Both effects were reversed by FBP which also decreased TGF-β1 levels in comparison to both control and Fe groups. FBP, also, did not present scavenger activity in the DPPH assay. The treatment with FBP resulted in decreased proliferation rate, Col-1 expression and TGF-β1 release by HSC cells. Furthermore, activated PPAR-γ and increased lipid droplets induce cells to become quiescent, which is a key event to reversion of hepatic fibrosis. FBP also chelates iron showing potential to improve Cell redox state.

Fructose-1,6-bisphosphate prevents pulmonary fibrosis by regulating extracellular matrix deposition and inducing phenotype reversal of lung myofibroblasts

“…Three days after FBP exposure, both healthy and fibrotic cells were significantly affected by FBP in vitro , showing signs of going to a quiescent state that is characteristic of normal fibroblasts. In agreement with these results, previous studies showed that FBP treatment in vitro promotes the deactivation of liver fibroblasts [14] even in the presence of free iron that activates fibroblasts to become myofibroblasts [15]. These results mirror some of the in vivo experiments, showing that FBP can have protective effects in a more complex system such as intact tissues.…”

“…As PFK activity is inhibited by high levels of ATP and low pH [54], FBP administration could even result in a halt on PFK activity, leading to an inhibition of glycolytic pathway and consequent downregulation of fibrosis. Others report that FBP could upregulate the expression of PPARγ in hepatic stellate cells, which could increase fatty acid oxidation and decrease glycolysis [15]. Further studies are necessary to determine the exact role of FBP in cell metabolism, which are currently underway.…”

“…An earlier study found that activated liver myofibroblasts, or hepatic stellate cells, underwent a phenotype reversal associated with quiescence, decreased proliferation, and accumulation of lipid droplets when treated in vitro with FBP, all of which are characteristics of normal healthy fibroblast [14]. This protective effect of FBP was maintained even when these cells were concomitantly exposed to high doses of free iron, that sustains activation of stellate cells [15]. A previous study on lung fibrosis showed that FBP can prevent bleomycin-induced fibrosis development in mice [16], however, the molecular basis of this effect remains unknown.…”

An optimized method for Oil Red O staining with the salicylic acid ethanol solution

“…The APRE-19 human retinal epithelial cells [ 30 , 31 ] were induced by sodium oleate for 48 hours to be positively stained with ORO. The physiological functions of hepatic stellate cells in the liver are mainly involved in the function of vitamin A metabolism and storing fat, the quiescent hepatic stellate cells are rich in fat droplets [ 32 , 33 ]. HST-T6 hepatic stellate cell line was induced with 100 μmol/L sodium oleate and 10 μmol/L all-trans retinoic acid for 3–5 days to be returned to its quiescent state.…”

Trace Elements, PPARs, and Metabolic Syndrome

“…Various in vitro studies have reported that iron treatment activated HSCs, which was accompanied by decreasing PPAR-γ expression. Dias et al [160] discovered the fact that fructose-1,6-bisphosphate (FBP), serving as a novel iron chelator, could reverse activation in the mouse GRX HSC cell line, leading to a quiescent state, by recovering Ppar-γ expression dampened by iron.…”