In vivo 31P magnetic resonance spectroscopy study of mouse cerebral NAD content and redox state during neurodevelopment

Abstract

Nicotinamide adenine dinucleotide (NAD) is an important cofactor of energy-producing pathways. The redox ratio (NAD+/NADH) reflects the cellular oxidoreductive state. Oxidative stress and redox dysregulation have been suggested to contribute to various neurological diseases. The assessment of NAD content has been recently demonstrated in large animals and human brains by 31P magnetic resonance spectroscopy. However, its measurement in small rodents has never been attempted. The purpose of this study was to investigate, in vivo, the NAD content during mouse brain neurodevelopment. 31P-MR-spectra were acquired in the mouse brain at postnatal days P20, P40, P90 and P250 at 14.1 T using a 3D-localization sequence. High spectral quality was achieved at 14.1 T. NAD+ and NADH were quantified with mean Cramér-Rao lower bound of 10% and 14%, respectively. An increase in NAD+/NADH was observed from P20 to P250 due to a decrease in [NADH]. The intracellular pH was significantly reduced with age, while the free [Mg2+] in the brain was significantly increased. This study demonstrates for the first time the feasibility of the measurement of NAD content in vivo in mouse brains during development, which opens the prospect of longitudinally studying energy metabolism and redox dysfunction in mouse models of brain pathology.

Developmental changes in cerebral NAD and neuroenergetics of an antioxidant compromised mouse model of schizophrenia

“…Apodization with a 10 Hz exponential function was applied to all spectra prior to spectral quantification. The 31 P metabolites quantification was effectuated with a basis-set prepared with simulated 31 P spectra including PCr, α -ATP, β -ATP, γ -ATP, Pi int (intracellular inorganic phosphate), Pi ext (extracellular inorganic phosphate), PE (phophothanolamine), PC (phosphocholine), GPC (glycerophosphocholine), GPE (glycerophosphoethanolamine), MP (membrane phospholipid), NADH, NAD + , with respective linewidths 15 . Uridine diphosphate glucose (UDPG) is a phosphorylated sugar intermediate in biochemical reactions, and it contains resonances overlapping with NADH and NAD + .…”

“…Due to the low concentration of UDPG and low sensitivity in mouse brain, additional analysis was performed with summed age pooled spectra with the inclusion of UDPG in the basis-set to quantify its level and to evaluate its effect on NAD quantification results. Physiological parameters (pH int and free [Mg 2+ ] ) were calculated from chemical shift differences between 31 P metabolites (details of the calculation can be find herein 15 ).…”

“…In this study, we aim to assess how a redox dysregulation caused by a deficit in GSH as seen in subsets of patients impacts RR, energy metabolism, excitatory and inhibitory metabolites along the postnatal development period. Previously, we demonstrated the feasibility of measuring RR, energy and membrane metabolites during mouse brain development using phosphorus magnetic resonance spectroscopy ( 31 P-MRS) 15 at 14.1T, which is challenging because of the low sensitivity due to the small brain size. Thus, we pushed towards the characterization of developmental alterations in a mouse model related to SZ, which displays reduced GSH synthesis ( gclm -KO) leading to several characteristic features of the disease, including impaired inhibitory GABAergic parvalbumin-positive interneurons (PVI) in numerous brain regions 16 , neuroinflammation, compromised mitophagy 17 , white matter and oligodendrocyte anomalies 18,19 together with altered behaviors 20 .…”

Redox and Immune Signaling in Schizophrenia: New Therapeutic Potential

“…The reduction in adult Gclm − / − mice is also similar to that seen in adult patients with SZ ( Kim et al, 2017 ). MRS studies in Gclm − / − animals also found changes in ATP, phosphocreatine, intracellular pH, glutamine and glutamate, and membrane phospholipid metabolites at P20 ( Skupienski et al, 2020 ).…”

In Vitro 31P MR Chemical Shifts of In Vivo-Detectable Metabolites at 3T as a Basis Set for a Pilot Evaluation of Skeletal Muscle and Liver 31P Spectra with LCModel Software

“…Its application for the analysis of 31 P spectra with signals resonating in the spectral range of about 30 ppm is more difficult and is not often used. Recently, however, a successful modification of the input parameters of the calculation of 31 P and 13 C spectra was proposed [16,[67][68][69], which enabled the correct definition of the baseline of the spectrum. We adapted these input parameters, and we used our basis set for the analysis of 31 P spectra of muscles and the liver.…”