Limits...
Preferential Accumulation of 14C-N-Glycolylneuraminic Acid over 14C-N-Acetylneuraminic Acid in the Rat Brain after Tail Vein Injection.

Taguchi R, Minami A, Matsuda Y, Takahashi T, Otsubo T, Ikeda K, Suzuki T - PLoS ONE (2015)

Bottom Line: Brain autoradiography indicated that 14C-Neu5Gc was accumulated predominantly in the hippocampus. 14C-Neu5Gc transferred into the brain was incorporated into gangliosides including GM1, GD1a, GD1b, GT1b and GQ1b.Reduction of 14C-Neu5Gc after intracerebroventricular infusion was slower than that of 14C-Neu5Ac in the brain and hippocampus.The results suggest that Neu5Gc is transferred from blood into the brain across the blood brain barrier and accumulates in the brain more preferentially than does Neu5Ac.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.

ABSTRACT
The two main molecular species of sialic acid existing in nature are N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc). Neu5Ac is abundant in mammalian brains and plays crucial roles in many neural functions. In contrast, Neu5Gc is present only at a trace level in vertebrate brains. The brain-specific suppression of Neu5Gc synthesis, which is a common feature in mammals, suggests that Neu5Gc has toxicity against brain functions. However, in vivo kinetics of Neu5Gc in the whole body, especially in the brain, has not been studied in sufficient detail. To determine the in vivo kinetics of Neu5Gc, 14C-Neu5Gc was enzymatically synthesized and injected into rat tail veins. Although most of 14C-Neu5Gc was excreted in urine, a small amount of 14C-Neu5Gc was detected in the brain. Brain autoradiography indicated that 14C-Neu5Gc was accumulated predominantly in the hippocampus. 14C-Neu5Gc transferred into the brain was incorporated into gangliosides including GM1, GD1a, GD1b, GT1b and GQ1b. Reduction of 14C-Neu5Gc after intracerebroventricular infusion was slower than that of 14C-Neu5Ac in the brain and hippocampus. The results suggest that Neu5Gc is transferred from blood into the brain across the blood brain barrier and accumulates in the brain more preferentially than does Neu5Ac.

No MeSH data available.


Related in: MedlinePlus

Incorporation of 14C-Neu5Gc into gangliosides in the brain after tail vein injection.(A) Three hr after tail vein injection of 14C-Neu5Gc (n = 3) or 14C-Neu5Ac (n = 3), chloroform-methanol soluble (S) and insoluble (I) fractions (Fr.) were obtained from the rat brain and radioactivity was measured. N.D., not detected. **P < 0.001. (B) After applying the lipid fraction onto a phenyl sepharose column, the column was washed with C/M (9:1, fr. 1) and C/M (85:15, fr. 2), and then gangliosides were eluted with C/M (1:1, fr. 3) and methanol (fr. 4). Gangliosides in each fraction were analyzed by TLC. (C) The radioactivity in each fraction is shown as a relative value to the total radioactivities in all four fractions (14C-Neu5Gc, n = 3; 14C-Neu5Ac, n = 3). (D) Gangliosides were separated by HPTLC using C/M/0.25% CaCl2 (50:40:10, v/v/v) and visualized with resorcinol/HCl reagent. (E and F) Radioactivities in each band are shown as relative values to the total radioactivities in fr. 3 (E, n = 3) or fr. 4 (F, n = 4).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4476740&req=5

pone.0131061.g005: Incorporation of 14C-Neu5Gc into gangliosides in the brain after tail vein injection.(A) Three hr after tail vein injection of 14C-Neu5Gc (n = 3) or 14C-Neu5Ac (n = 3), chloroform-methanol soluble (S) and insoluble (I) fractions (Fr.) were obtained from the rat brain and radioactivity was measured. N.D., not detected. **P < 0.001. (B) After applying the lipid fraction onto a phenyl sepharose column, the column was washed with C/M (9:1, fr. 1) and C/M (85:15, fr. 2), and then gangliosides were eluted with C/M (1:1, fr. 3) and methanol (fr. 4). Gangliosides in each fraction were analyzed by TLC. (C) The radioactivity in each fraction is shown as a relative value to the total radioactivities in all four fractions (14C-Neu5Gc, n = 3; 14C-Neu5Ac, n = 3). (D) Gangliosides were separated by HPTLC using C/M/0.25% CaCl2 (50:40:10, v/v/v) and visualized with resorcinol/HCl reagent. (E and F) Radioactivities in each band are shown as relative values to the total radioactivities in fr. 3 (E, n = 3) or fr. 4 (F, n = 4).

Mentions: To determine whether 14C-Neu5Gc transferred from blood to the brain is used for a component of sialylglycoconjugates such as glycolipids and glycoproteins, we measured radioactivity levels in chloroform-methanol soluble and insoluble fractions derived from the brain after 14C-Neu5Gc injection into a tail vein. Although radioactivity was detected in both fractions, the chloroform-methanol soluble fraction (lipid fraction) showed higher radioactivity than that of the chloroform-methanol insoluble fraction including proteins (Fig 5A). In both fractions, radioactivity after 14C-Neu5Gc injection was higher than that after 14C-Neu5Ac injection.


Preferential Accumulation of 14C-N-Glycolylneuraminic Acid over 14C-N-Acetylneuraminic Acid in the Rat Brain after Tail Vein Injection.

Taguchi R, Minami A, Matsuda Y, Takahashi T, Otsubo T, Ikeda K, Suzuki T - PLoS ONE (2015)

Incorporation of 14C-Neu5Gc into gangliosides in the brain after tail vein injection.(A) Three hr after tail vein injection of 14C-Neu5Gc (n = 3) or 14C-Neu5Ac (n = 3), chloroform-methanol soluble (S) and insoluble (I) fractions (Fr.) were obtained from the rat brain and radioactivity was measured. N.D., not detected. **P < 0.001. (B) After applying the lipid fraction onto a phenyl sepharose column, the column was washed with C/M (9:1, fr. 1) and C/M (85:15, fr. 2), and then gangliosides were eluted with C/M (1:1, fr. 3) and methanol (fr. 4). Gangliosides in each fraction were analyzed by TLC. (C) The radioactivity in each fraction is shown as a relative value to the total radioactivities in all four fractions (14C-Neu5Gc, n = 3; 14C-Neu5Ac, n = 3). (D) Gangliosides were separated by HPTLC using C/M/0.25% CaCl2 (50:40:10, v/v/v) and visualized with resorcinol/HCl reagent. (E and F) Radioactivities in each band are shown as relative values to the total radioactivities in fr. 3 (E, n = 3) or fr. 4 (F, n = 4).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4476740&req=5

pone.0131061.g005: Incorporation of 14C-Neu5Gc into gangliosides in the brain after tail vein injection.(A) Three hr after tail vein injection of 14C-Neu5Gc (n = 3) or 14C-Neu5Ac (n = 3), chloroform-methanol soluble (S) and insoluble (I) fractions (Fr.) were obtained from the rat brain and radioactivity was measured. N.D., not detected. **P < 0.001. (B) After applying the lipid fraction onto a phenyl sepharose column, the column was washed with C/M (9:1, fr. 1) and C/M (85:15, fr. 2), and then gangliosides were eluted with C/M (1:1, fr. 3) and methanol (fr. 4). Gangliosides in each fraction were analyzed by TLC. (C) The radioactivity in each fraction is shown as a relative value to the total radioactivities in all four fractions (14C-Neu5Gc, n = 3; 14C-Neu5Ac, n = 3). (D) Gangliosides were separated by HPTLC using C/M/0.25% CaCl2 (50:40:10, v/v/v) and visualized with resorcinol/HCl reagent. (E and F) Radioactivities in each band are shown as relative values to the total radioactivities in fr. 3 (E, n = 3) or fr. 4 (F, n = 4).
Mentions: To determine whether 14C-Neu5Gc transferred from blood to the brain is used for a component of sialylglycoconjugates such as glycolipids and glycoproteins, we measured radioactivity levels in chloroform-methanol soluble and insoluble fractions derived from the brain after 14C-Neu5Gc injection into a tail vein. Although radioactivity was detected in both fractions, the chloroform-methanol soluble fraction (lipid fraction) showed higher radioactivity than that of the chloroform-methanol insoluble fraction including proteins (Fig 5A). In both fractions, radioactivity after 14C-Neu5Gc injection was higher than that after 14C-Neu5Ac injection.

Bottom Line: Brain autoradiography indicated that 14C-Neu5Gc was accumulated predominantly in the hippocampus. 14C-Neu5Gc transferred into the brain was incorporated into gangliosides including GM1, GD1a, GD1b, GT1b and GQ1b.Reduction of 14C-Neu5Gc after intracerebroventricular infusion was slower than that of 14C-Neu5Ac in the brain and hippocampus.The results suggest that Neu5Gc is transferred from blood into the brain across the blood brain barrier and accumulates in the brain more preferentially than does Neu5Ac.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.

ABSTRACT
The two main molecular species of sialic acid existing in nature are N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc). Neu5Ac is abundant in mammalian brains and plays crucial roles in many neural functions. In contrast, Neu5Gc is present only at a trace level in vertebrate brains. The brain-specific suppression of Neu5Gc synthesis, which is a common feature in mammals, suggests that Neu5Gc has toxicity against brain functions. However, in vivo kinetics of Neu5Gc in the whole body, especially in the brain, has not been studied in sufficient detail. To determine the in vivo kinetics of Neu5Gc, 14C-Neu5Gc was enzymatically synthesized and injected into rat tail veins. Although most of 14C-Neu5Gc was excreted in urine, a small amount of 14C-Neu5Gc was detected in the brain. Brain autoradiography indicated that 14C-Neu5Gc was accumulated predominantly in the hippocampus. 14C-Neu5Gc transferred into the brain was incorporated into gangliosides including GM1, GD1a, GD1b, GT1b and GQ1b. Reduction of 14C-Neu5Gc after intracerebroventricular infusion was slower than that of 14C-Neu5Ac in the brain and hippocampus. The results suggest that Neu5Gc is transferred from blood into the brain across the blood brain barrier and accumulates in the brain more preferentially than does Neu5Ac.

No MeSH data available.


Related in: MedlinePlus