Jumpei Sasabe 교수

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder involving an extensive loss of motoneurons. Aberrant excitability of motoneurons has been implicated in the pathogenesis of selective motoneuronal death in ALS. D-serine, an endogenous coagonist of N-methyl-D-aspartate receptors, exacerbates motoneuronal death and is increased both in patients with sporadic/familial ALS and in a G93A-SOD1 mouse model of ALS (mSOD1 mouse). More recently, a unique mutation in the D-amino aci

Mammalian innate and adaptive immune systems use the pattern recognition receptors, such as toll-like receptors, to detect conserved bacterial and viral components. Bacteria synthesize diverse D-amino acids while eukaryotes and archaea generally produce two D-amino acids, raising the possibility that many of bacterial D-amino acids are bacteria-specific metabolites. Although D-amino acids have not been identified to bind to any known pattern recognition receptors, D-amino acids are enantioselect

The imbalance of blood and urine amino acids in renal failure has been studied mostly without chiral separation. Although a few reports have shown the presence of D-serine, an enantiomer of L-serine, in the serum of patients with severe renal failure, it has remained uncertain how serine enantiomers are deranged in the development of renal failure. In the present study, we have monitored serine enantiomers using a two-dimensional HPLC system in the serum and urine of mice after renal ischemia-re

It has been proposed that D-amino acid oxidase (DAO) plays an essential role in degrading D-serine, an endogenous coagonist of N-methyl-D-aspartate (NMDA) glutamate receptors. DAO shows genetic association with amyotrophic lateral sclerosis (ALS) and schizophrenia, in whose pathophysiology aberrant metabolism of D-serine is implicated. Although the pathology of both essentially involves the forebrain, in rodents, enzymatic activity of DAO is hindbrain-shifted and absent in the region. Here, we s

Living organisms enantioselectively employ L-amino acids as the molecular architecture of protein synthesized in the ribosome. Although L-amino acids are dominantly utilized in most biological processes, accumulating evidence points to the distinctive roles of D-amino acids in non-ribosomal physiology. Among the three domains of life, bacteria have the greatest capacity to produce a wide variety of D-amino acids. In contrast, archaea and eukaryotes are thought generally to synthesize only two ki

The mechanism underlying selective motoneuronal loss in amyotrophic lateral sclerosis (ALS) remains uncertain. The pathogenesis appears to be a complex and multifactorial process. Glutamate excitotoxicity to motoneuron is one of the most intensely investigated targets for the treatment of ALS, and excessive motoneuronal excitation by glutamate through ionotropic glutamate receptors has been mainly demonstrated. However, development of clinically effective drug targeting glutamate is sometimes di

d-Serine modulates excitatory neurotransmission by binding to N-methyl-d-aspartate glutamate receptors. d-Amino acid oxidase (DAO) degrades d-amino acids, such as d-serine, in the central nervous system, and is associated with neurological and psychiatric disorders. However, cell types that express brain DAO remain controversial, and whether brain DAO influences systemic d-amino acids in addition to brain d-serine remains unclear. Here, we created astrocyte-specific DAO-conditional knockout mice

Activation of N-methyl-_d-aspartate receptors (NMDARs) requires binding of a co-agonist in addition to _l-glutamate. _d-serine binds to the co-agonist site on GluN1 subunits of NMDARs and modulates glutamatergic neurotransmission. While loss of GluN1 subunits in mice results in neonatal death due to respiratory failure, animals that lack a _d-serine synthetic enzyme, serine racemase (SR), show grossly normal growth. However, SR-independent origins of <sub>

Biomarkers that accurately reflect renal function are essential in management of chronic kidney diseases (CKD). However, in children, age/physique and medication often alter established renal biomarkers. We studied whether amino acid enantiomers in body fluids correlate with renal function and whether they are influenced by physique or steroid medication during development. We conducted a prospective study of children 2 to 18 years old with and without CKD. We analyzed associations of serine/asp

Abstract Multiple sclerosis (MS) is characterized by chronic inflammatory demyelination involving complex interplay between the central nervous and immune systems. Neuroinflammation triggers cellular reorganization requiring l -serine for sustained syntheses of membrane lipids and nucleic acids, whereas it causes aberrant glutamatergic neurotransmission involving d -serine. However, significance of serine metabolism in MS pathology remains unexplored. Here we show that serine chiral homeostasis

Organisms use amino acids predominantly in l-configuration. In contrast, a series of studies show that a variety of d-amino acids also occur in mammals, and amino acid homochirality is not complete. Mammals de novo synthesize most amino acids with l-configuration, but serine and aspartate are converted from l- to d-configuration by endogenous enzymes. In addition to endogenous syntheses of d-amino acids, symbiotic bacteria in mammals chiral-convert amino acids, including alanine, glutamate, prol