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

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.

Redox signaling and Alzheimer’s disease: from pathomechanism insights to biomarker discovery and therapy strategy

“…In addition, there is a significant relationship between cerebral glucose hypometabolism and elevated CSF lactate in brain areas typically showing AD neurodegeneration, suggesting neural glucose hypometabolism might affect the cognitive efficacy by damaging brain energetic machine [29]. Moreover, fructose-1,6bisphosphate is another glycolytic intermediate that shows neuroprotective effect against various harmful conditions in many brain injury models [30]. Particularly, fructose-1,6bisphosphate could improve cerebral metabolic outcomes via ameliorating inflammation and oxidative stress and preserving glucose metabolism integrity in sepsis [31].…”

Lowering glucose enhances BACE1 activity and Aβ generation in mouse brain slice cultures

“…The means by which these compounds decreased Aβ is unclear will be an important topic for further investigation. FBP is of particular interest as it its currently being suggested as a potential therapy for epilepsy and ischemia [63,64,66]. While glucose failed to have a significant effect upon Aβ production in the pyruvate and FBP experiments, this is likely due to the fact that 40mM and 2.8mM glucose OHSCs were not cultured from the same animals.…”

“…The copyright holder for this preprint this version posted March 14, 2024. ; https://doi.org/10.1101/2024.03.12.584616 doi: bioRxiv preprint therapy for epilepsy and ischemia [63,64,66]. While glucose failed to have a significant effect upon Aβ production in the pyruvate and FBP experiments, this is likely due to the fact that 40mM and 2.8mM glucose OHSCs were not cultured from the same animals.…”

“…Fructose 1,6-bisphosphate (FBP) is positioned as the third metabolite in the glycolysis pathway and its production is considered the most crucial rate limiting step of glycolysis [62]. It has been proposed as a therapeutic intervention for conditions such as ischemia, epilepsy, and arthritis [63][64][65][66]. To examine whether FBP could counteract glucose-induced alterations in Aβ, WT OHSCs underwent a 7 day treatment with 500µM FBP, combined with varying glucose concentrations.…”