Vitamin C Is Not Essential for Carnitine Biosynthesis in Vivo: Verification in Vitamin C-Depleted Senescence Marker Protein-30/Gluconolactonase Knockout Mice

Furusawa, Hajime; Sato, Yasunori; Tanaka, Yasukazu; Inai, Yoko; Amano, Akiko; Iwama, Mizuki; Kondo, Yoshitaka; Handa, Shizuo; Murata, Akira; Nishikimi, Morimitsu; Goto, Sataro; Maruyama, Naoki; Takahashi, Ryutaro; Ishigami, Akihito

doi:10.1248/bpb.31.1673

Cited by 39 publications

(24 citation statements)

References 46 publications

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“…Although mRNA for carnitine transporters was expressed in placenta, Slc23a1 -/-pups could not be rescued by feeding carnitine to Slc23a1 -/-dams throughout pregnancy. These data are consistent with observations that mice unable to synthesize ascorbate have normal carnitine synthesis (37). There was no evidence of scurvy on histopathologic examination of newborn Slc23a1 -/-pups compared with Slc23a1 +/+ littermates.…”

Section: Discussionsupporting

confidence: 90%

Vitamin C transporter Slc23a1 links renal reabsorption, vitamin C tissue accumulation, and perinatal survival in mice

et al. 2010

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Levels of the necessary nutrient vitamin C (ascorbate) are tightly regulated by intestinal absorption, tissue accumulation, and renal reabsorption and excretion. Ascorbate levels are controlled in part by regulation of transport through at least 2 sodium-dependent transporters: Slc23a1 and Slc23a2 (also known as Svct1 and Svct2, respectively). Previous work indicates that Slc23a2 is essential for viability in mice, but the roles of Slc23a1 for viability and in adult physiology have not been determined. To investigate the contributions of Slc23a1 to plasma and tissue ascorbate concentrations in vivo, we generated Slc23a1 -/-mice. Compared with wild-type mice, Slc23a1 -/-mice increased ascorbate fractional excretion up to 18-fold. Hepatic portal ascorbate accumulation was nearly abolished, whereas intestinal absorption was marginally affected. Both heterozygous and knockout pups born to Slc23a1 -/-dams exhibited approximately 45% perinatal mortality, and this was associated with lower plasma ascorbate concentrations in dams and pups. Perinatal mortality of Slc23a1 -/-pups born to Slc23a1 -/-dams was prevented by ascorbate supplementation during pregnancy. Taken together, these data indicate that ascorbate provided by the dam influenced perinatal survival. Although Slc23a1 -/-mice lost as much as 70% of their ascorbate body stores in urine daily, we observed an unanticipated compensatory increase in ascorbate synthesis. These findings indicate a key role for Slc23a1 in renal ascorbate absorption and perinatal survival and reveal regulation of vitamin C biosynthesis in mice.

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Section: Discussionsupporting

confidence: 90%

Vitamin C transporter Slc23a1 links renal reabsorption, vitamin C tissue accumulation, and perinatal survival in mice

et al. 2010

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“…Wild-type (WT), C57BL/6, and SMP30 KO mice were fed with a commercial chow (CRF-1; Oriental Kobo, Tokyo, Japan) and had free access to water containing 1.5 g/l VC in 10 M EDTA (pH 8.0) until they were weaned at the age of 30 days. We (12) have previously reported that this concentration of VCcontaining water is sufficient to keep VC content within normal range in various organs of SMP30 KO mice. VC-containing water was prepared and exchanged twice a week.…”

Section: Methodsmentioning

confidence: 80%

“…The supernatant was obtained by centrifugation at 21,000 g for 15 min at 4°C and immediately frozen at Ϫ80°C until use. Total VC levels were determined by using an HPLC electrochemical detection method as described previously (12).…”

Section: Methodsmentioning

confidence: 99%

Complete lack of vitamin C intake generates pulmonary emphysema in senescence marker protein-30 knockout mice

Koike

Kondo

Sekiya

et al. 2010

American Journal of Physiology-Lung Cellular and Molecular Phys

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Vitamin C (VC) is a potent antioxidant and plays an essential role in collagen synthesis. As we previously reported, senescence marker protein-30 (SMP30) knockout (KO) mice cannot synthesize VC due to the genetic disruption of gluconolactonase (i.e., SMP30). Here, we utilized SMP30 KO mice deprived of VC and found that VC depletion caused pulmonary emphysema due to oxidative stress and a decrease of collagen synthesis by the third month of age. We grew SMP30 KO mice and wild-type (WT) mice on VC-free chow and either VC water [VC(ϩ)] or plain water [VC(Ϫ)] after weaning at 4 wk of age. Morphometric findings and reactive oxygen species (ROS) in the lungs were evaluated at 3 mo of age. No VC was detected in the lungs of SMP30 KO VC(Ϫ) mice, but their ROS increased 50.9% over that of the VC(ϩ) group. Moreover, their collagen content in the lungs markedly decreased, and their collagen I mRNA decreased 82.2% compared with that of the WT VC(Ϫ) group. In the SMP30 KO VC(Ϫ) mice, emphysema developed [21.6% increase of mean linear intercepts (MLI) and 42.7% increase of destructive index compared with VC(ϩ) groups], and the levels of sirtuin 1 (Sirt1) decreased 16.8%. However, VC intake increased the MLI 16.2% and thiobarbituric acid reactive substances 22.2% in WT mice, suggesting that an excess of VC can generate oxidative stress and may be harmful during this period of lung development. These results suggest that VC plays an important role in lung development through affecting oxidant-antioxidant balance and collagen synthesis. chronic obstructive pulmonary disease; collagen VITAMIN C (VC) is a water-soluble, hexonic sugar acid that has two dissociable protons (40) and is abundant in fluids of the lung epithelial lining (50). VC scavenges free radicals such as superoxide (34), singlet oxygen (4), and hydroxyl radicals (2). Several reports indicate that VC has a beneficial effect on lung function but, when depleted during aging, may promote chronic obstructive pulmonary disease (COPD; Refs. 41, 44). On the other hand, VC also plays an essential role in collagen synthesis because it acts as a cofactor for prolyl hydroxylase to catalyze hydroxyproline synthesis, which is involved in collagen helix stabilization (33, 38). Furthermore, VC stimulates collagen biosynthesis not only by promoting the activity of the prolyl hydroxylase, but also by increasing the mRNA of collagen (I and III; Refs. 13,35).Senescence marker protein-30 (SMP30) is characterized by its ever-decreasing content in the liver, kidney, and lung with aging, a decrease that is androgen-independent (11). To clarify the physiological role of SMP30 in age-associated organ disorders, we used gene targeting to establish the SMP30 knockout (KO) mouse from C57BL/6 mice (17). Recently, we (24) reported that SMP30 has gluconolactonase (GNL) activity. Since GNL is a key enzyme in the VC biosynthetic pathway of mammals, mice deprived of GNL (SMP30 KO mice) lack the ability to synthesize VC (19). We (42) further discovered that oxidative stress is greater in the lungs o...

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“…Determination of AA AA was analyzed by using a HPLC-ECD method, as described, [21][22][23] consisting of a Waters 2695 separations module coupled with a Waters 2465 electrochemical detector (Nihon Waters, Tokyo, Japan). A vacuum degasser, quaternary pump, and thermostated autosampler were included in the Waters 2695 separations module.…”

Section: Methodsmentioning

confidence: 99%

Determination of Dehydroascorbic Acid in Mouse Tissues and Plasma by Using Tris(2-carboxyethyl)phosphine Hydrochloride as Reductant in Metaphosphoric Acid/Ethylenediaminetetraacetic Acid Solution

Sato

Uchiki

Iwama

et al. 2010

Biological & Pharmaceutical Bulletin

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Ascorbic acid (AA) functions as an electron donor and scavenges free radicals such as superoxide radicals 1) and hydroxyl radicals 2) in vitro. Moreover, AA is essential for posttranslational proline hydroxylation of collagen molecules, 3) after which hydroxyproline residues play a critical role in stabilizing the triple helical structure of collagen.4) Dehydroascorbic acid (DHA), the oxidized form of AA, is generated as a result of these reactions. The biological activity of DHA has been considered equivalent to that of AA, because intracellular DHA is rapidly reduced to AA by dehydroascorbic acid reductase. 5) However, Ogiri et al. reported that DHA had less than 10% of AA's biological efficiency on a molar basis, judging from experiments with the inherently scorbutic ODS rat, which is a convenient animal model for investigating the metabolism of AA in humans. 6) Moreover, May et al. noted that the human mature red blood cells they studied did not have sodium-dependent vitamin C transporters (SVCT1 and SVCT2) yet manifested a very low late uptake of radiolabeled AA. 7) In contrast, human mature red blood cells efficiently took up DHA from blood via a glucose transporter 1 (Glut1).8) Erythrocyte Glut1 and associated DHA uptake are unique traits of humans and the few other mammals that have lost the ability to synthesize AA in vivo. Furthermore, DHA is known to enter mitochondria via Glut1 and undergo reduction to AA in the mitochondria. 9) AA, which enters mitochondria as DHA, also protects mitochondria from oxidative injury. Thus, because DHA possesses unique physiological features, distinct from those of AA, establishment of a simple and accurate method of assessing the presence of DHA is very important.AA in biological samples is routinely evaluated by using HPLC systems. AA's maximum absorbance at 265 nm in HPLC coupled with detection by UV light are widely used for such analyses.10) Other means of AA determination subsequently developed are the ketone derivatization method with 2,4-dinitrophenylhydrazine (DNPH) or o-phenylenediamine and HPLC coupled with electrochemical detection (ECD) system. 11-13) HPLC-ECD is widely used at present, because of this assay's great sensitivity and specificity. 14)However, for DHA determination, the UV detector is not suitable, because DHA's maximum absorbance at 220 nm provides only insensitive and nonselective results. DHA is also difficult to detect with HPLC-ECD because of its low electroactivity. Therefore, a DHA concentration is typically calculated by subtracting AA concentration from the total AA (AAϩDHA) concentration determined in a different chromatographic run. The total AA concentration is usually calculated by reducing the DHA to AA with sulfhydryl compounds including dithiothreitol (DTT) (Fig. 1), mercaptoethanol and homocysteine.15) However, the reducing ability of these sulfhydryl compounds is limited to a narrow neutral pH range. In general, metaphosphoric acid (MPA) and EDTA are used to stabilize the AA and DHA in biological samples.16) Therefore, raising...

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Vitamin C Is Not Essential for Carnitine Biosynthesis in Vivo: Verification in Vitamin C-Depleted Senescence Marker Protein-30/Gluconolactonase Knockout Mice

Cited by 39 publications

References 46 publications

Vitamin C transporter Slc23a1 links renal reabsorption, vitamin C tissue accumulation, and perinatal survival in mice

Vitamin C transporter Slc23a1 links renal reabsorption, vitamin C tissue accumulation, and perinatal survival in mice

Complete lack of vitamin C intake generates pulmonary emphysema in senescence marker protein-30 knockout mice

Determination of Dehydroascorbic Acid in Mouse Tissues and Plasma by Using Tris(2-carboxyethyl)phosphine Hydrochloride as Reductant in Metaphosphoric Acid/Ethylenediaminetetraacetic Acid Solution

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