title: D-serine uptake and release in PC-12 cells measured by chiral microchip electrophoresis-mass spectrometry.
abstract: Previous work has established that D-serine (D-Ser) plays important roles in certain neurological processes. Study on its uptake/storage and release by neuronal cells is highly significant for elucidating relevant mechanisms. In this work, PC-12 cells were incubated with racemic Ser (100 μM each enantiomer). After incubation, both intra- and extracellular levels of D-Ser and L-Ser were quantified by chiral microchip electrophoresis with mass spectrometric detection. It was found the cells preferably took up D-Ser over L-Ser. After 120 min incubation, D-Ser percentage ([D-Ser]/([D-Ser] + [L-Ser]) in the culture media changed from 50% to 9% while inside the cells it increased from 13% to 67%. Small neutral amino acids such as threonine impaired D-Ser uptake. Ser release was studied by using PC-12 cells preloaded with D-Ser. KCl, Glu, and Gly evoked Ser release. Interestingly, while depolarization by KCl evoked release of Ser as a D-Ser/L-Ser mixture of 1:1 ratio, the stereoisomeric composition of Ser released due to Glu exposure varied with the exposure time, ranging from 73% D-Ser (i.e., [D-Ser] > [L-Ser]) at 2 min to 44% (i.e., [D-Ser] < [L-Ser]) at 14 min, clearly indicating a stereochemical preference for D-Ser in Ser release from neuronal cells evoked by Glu-receptor activation.
authors.affiliation: †Department of Chemistry and Biochemistry, Jackson State University, 1400 Lynch Street, Jackson, Mississippi 39217, United States.
authors.forename: Xiangtang
authors.initials: X
authors.lastname: Li
authors.affiliation: †Department of Chemistry and Biochemistry, Jackson State University, 1400 Lynch Street, Jackson, Mississippi 39217, United States.
authors.forename: Cassandra
authors.initials: C
authors.lastname: McCullum
authors.affiliation: †Department of Chemistry and Biochemistry, Jackson State University, 1400 Lynch Street, Jackson, Mississippi 39217, United States.|‡College of Chemistry and Chemical Engineering, Guangxi Normal University, Guilin 541004, China.
authors.forename: Shulin
authors.initials: S
authors.lastname: Zhao
authors.affiliation: †Department of Chemistry and Biochemistry, Jackson State University, 1400 Lynch Street, Jackson, Mississippi 39217, United States.|§Zhongnan Hospital, Wuhan University, Wuhan 430071, China.
authors.forename: Hankun
authors.initials: H
authors.lastname: Hu
authors.affiliation: †Department of Chemistry and Biochemistry, Jackson State University, 1400 Lynch Street, Jackson, Mississippi 39217, United States.
authors.forename: Yi-Ming
authors.initials: YM
authors.lastname: Liu
mesh_terms: D026962:Amino Acid Transport System ASC / Q000378:metabolism; D000818:Animals; D046209:Electrophoresis, Microchip / Q000379:methods; D018698:Glutamic Acid / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods; D009474:Neurons / Q000378:metabolism*; D016716:PC12 Cells; D011189:Potassium Chloride / Q000378:metabolism; D051381:Rats; D012694:Serine / Q000378:metabolism*; D013237:Stereoisomerism
chemical_list: D026962:Amino Acid Transport System ASC; C583864:Slc7a10 protein, rat; D018698:Glutamic Acid; D012694:Serine; D011189:Potassium Chloride; D005998:Glycine
keywords: PC-12 cells; chiral analysis; d-Serine; microchip electrophoresis-mass spectrometry; release; uptake