Fructose-1,6-Bisphosphate Protects Hippocampal Rat Slices from NMDA Excitotoxicity.

Kamal M Yakoub,Barbara Tavazzi,Angela M Amorini,Marcello Ciaccio,Giuseppe Lazzarino,Valentina Di Pietro,Antonio Belli,Giuseppe Caruso,Concetta Scazzone,Giacomo Lazzarino

doi:10.3390/ijms20092239

Abstract

Effects of fructose 1,6-bisphosphate (F-1,6-P2) towards N-methyl-d-aspartate NMDA excitotoxicity were evaluated in rat organotypic hippocampal brain slice cultures (OHSC) challenged for 3 h with 30 μM NMDA, followed by incubations (24, 48, and 72 h) without (controls) and with F-1,6-P2 (0.5, 1 or 1.5 mM). At each time, cell necrosis was determined by measuring LDH in the medium. Energy metabolism was evaluated by measuring ATP, GTP, ADP, AMP, and ATP catabolites (nucleosides and oxypurines) in deproteinized OHSC extracts. Gene expressions of phosphofructokinase, aldolase, and glyceraldehyde-3-phosphate dehydrogenase were also measured. F-1,6-P2 dose-dependently decreased NMDA excitotoxicity, abolishing cell necrosis at the highest concentration tested (1.5 mM). Additionally, F-1,6-P2 attenuated cell energy imbalance caused by NMDA, ameliorating the mitochondrial phosphorylating capacity (increase in ATP/ADP ratio) Metabolism normalization occurred when using 1.5 mM F-1,6-P2. Remarkable increase in expressions of phosphofructokinase, aldolase and glyceraldehyde-3-phosphate dehydrogenase (up to 25 times over the values of controls) was also observed. Since this phenomenon was recorded even in OHSC treated with F-1,6-P2 with no prior challenge with NMDA, it is highly conceivable that F-1,6-P2 can enter into intact cerebral cells producing significant benefits on energy metabolism. These effects are possibly mediated by changes occurring at the gene level, thus opening new perspectives for F-1,6-P2 application as a useful adjuvant to rescue mitochondrial metabolism of cerebral cells under stressing conditions.

Highlights

Brain damage caused by acute and chronic neurological disorders (Alzheimer’s disease, Parkinson’s disease, multiple sclerosis) has some common biochemical features including ionic imbalance [1], cell energy failure [2] and increase in the release of neurotransmitters with inhibition of their reuptake [3]
Effects of fructose 1,6-bisphosphate (F-1,6-P2) towards N-methyl-d-aspartate NMDA excitotoxicity were evaluated in rat organotypic hippocampal brain slice cultures (OHSC) challenged for 3 h with 30 μM NMDA, followed by incubations (24, 48, and 72 h) without and with F-1,6-P2 (0.5, 1 or 1.5 mM)
Remarkable increase in expressions of phosphofructokinase, aldolase and glyceraldehyde-3-phosphate dehydrogenase was observed. Since this phenomenon was recorded even in OHSC treated with F-1,6-P2 with no prior challenge with NMDA, it is highly conceivable that F-1,6-P2 can enter into intact cerebral cells producing significant benefits on energy metabolism

Summary

Introduction

Brain damage caused by acute (ischemia, stroke, hypoxia, traumatic brain injury) and chronic neurological disorders (Alzheimer’s disease, Parkinson’s disease, multiple sclerosis) has some common biochemical features including ionic imbalance [1], cell energy failure [2] and increase in the release of neurotransmitters with inhibition of their reuptake [3]. This last phenomenon mainly involves glutamate, the most important excitotoxic neurotransmitter. Malfunctioning mitochondria cause increased production of reactive oxygen and nitrogen species (ROS and RNS), leading to the insurgence of oxidative/nitrosative stress [9], and release of proapoptotic factors, with consequent activation of caspases and the intrinsic apoptotic pathway [10]

Methods

Results

Conclusion