Mitochondrial gene‐knockout (ρ<sup>0</sup>) cells: A versatile model for exploring the secrets of trans‐plasma membrane electron transport

Scarlett, Debbie-Jane G; Herst, Patries M.; Tan, Ann Na; Prata, Cecilia; Berridge, Michael V.

doi:10.1002/biof.5520200404

Cited by 38 publications

(24 citation statements)

References 23 publications

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“…Cytochalasin B was also shown not to inhibit ascorbate uptake by pig coronary smooth muscle cells [30]. Although A10 cell ascorbate transport was not as sensitive to reduced GSH depletion by thiol reagents as that of cultured endothelial cells [29], immunoblotting of the SVCT2 confirmed the presence of this transporter in A10 cells, making it most likely to account for the transport features observed.…”

Section: Discussionmentioning

confidence: 96%

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Ascorbic Acid Uptake and Regulation of Type I Collagen Synthesis in Cultured Vascular Smooth Muscle Cells

et al. 2008

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Background/Aims: Vascular smooth muscle cells contribute both to the structure and function of arteries, but are also involved in pathologic changes that accompany inflammatory diseases such as atherosclerosis. Since inflammation is associated with oxidant stress, we examined the uptake and cellular effects of the antioxidant vitamin ascorbic acid in cultured A10 vascular smooth muscle cells. Methods/Results: A10 cells concentrated ascorbate against a gradient in a sodium-dependent manner, most likely on the sodium-dependent vitamin C transporter type 2 (SVCT2) ascorbate transporter, which was present in immunoblots of cell extracts. Although ascorbate did not affect A10 cell proliferation, it stimulated radiolabeled proline incorporation and type I collagen synthesis. The latter was evident in the cells as increases in proα1(I) collagen and conversion of proα1(I) and proα2(I) collagen to mature forms that were released from the cells and deposited as extracellular matrix. Intracellular type I procollagen maturation was optimal at intracellular ascorbate concentrations of 200 μM and below, which were readily achieved by culture of the cells at plasma physiologic ascorbate concentrations. Conclusion: These results show that the SVCT2 facilitates ascorbate uptake by vascular smooth muscle cells, which in turn increases both the synthesis and maturation of type I collagen.

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Section: Discussionmentioning

confidence: 96%

“…Specific ascorbate transport is known to be sensitive to the thiol-dependent redox state of the cell [29], and this was tested for A10 cells. As shown in figure 3, preincubation of A10 cells with L -buthionine sulfoximine modestly decreased ascorbate transport, whereas 1,3-bis(2-chloroethyl)-1-nitrosourea and diethylmaleate had no effect.…”

Section: Resultsmentioning

confidence: 99%

Ascorbic Acid Uptake and Regulation of Type I Collagen Synthesis in Cultured Vascular Smooth Muscle Cells

et al. 2008

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“…The PMRS is stimulated when mitochondrial function is impaired (47)(48)(49)(50). Considerable evidence suggests that during normal aging mitochondrial function declines in neurons in the brain, as indicated by decreased levels of activity of mitochondrial metabolic enzymes (51,52).…”

Section: Discussionmentioning

confidence: 99%

Calorie restriction up-regulates the plasma membrane redox system in brain cells and suppresses oxidative stress during aging

Hyun

Emerson

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

249

160

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The plasma membrane (PM) contains redox enzymes that provide electrons for energy metabolism and recycling of antioxidants such as coenzyme Q and ␣-tocopherol. Brain aging and neurodegenerative disorders involve impaired energy metabolism and oxidative damage, but the involvement of the PM redox system (PMRS) in these processes is unknown. Caloric restriction (CR), a manipulation that protects the brain against aging and disease, increased activities of PMRS enzymes (NADH-ascorbate free radical reductase, NADH-quinone oxidoreductase 1, NADH-ferrocyanide reductase, NADH-coenzyme Q10 reductase, and NADH-cytochrome c reductase) and antioxidant levels (␣-tocopherol and coenzyme Q10) in brain PM during aging. Age-related increases in PM lipid peroxidation, protein carbonyls, and nitrotyrosine were attenuated by CR, levels of PMRS enzyme activities were higher, and markers of oxidative stress were lower in cultured neuronal cells treated with CR serum compared with those treated with ad libitum serum. These findings suggest important roles for the PMRS in protecting brain cells against age-related increases in oxidative and metabolic stress.Alzheimer's disease ͉ reactive oxygen species ͉ coenzyme Q10 ͉ oxidoreductase

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“…The pH did not fall during the 30-minute measurement period. We investigated the effects of 3 metabolic inhibitors: 1) myxothiazol (1 g/ml), a mitochondrial electron-transport (cytochrome b-c1 segment) inhibitor; 2) sodium azide (NaN 3 ; 10 mM), which inhibits cytochrome c oxidase; and 3) diphenyleneiodonium (DPI; 20 M), a flavin-center inhibitor of nonmitochondrial cell surface NADPH oxidases (22,23).…”

Section: Methodsmentioning

confidence: 99%

Notochordal intervertebral disc cells: Sensitivity to nutrient deprivation

Guehring

Wilde

Sumner

et al. 2009

Arthritis & Rheumatism

119

164

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Objective. The nucleus pulposus (NP) of the intervertebral disc develops from the notochord. Humans and other species in which notochordal cells (NCs) disappear to be replaced by chondrocyte-like mature NP cells (MNPCs) frequently develop disc degeneration, unlike other species that retain NCs. The reasons for NC disappearance are unknown. In humans, the change in cell phenotype (to MNPCs) coincides with changes that decrease nutrient supply to the avascular disc. We undertook this study to test the hypothesis that the consequent nutrient stress could be associated with NC disappearance.Methods. We measured cell densities and metabolic rates in 3-dimensional cultures of porcine NCs and bovine MNPCs, and we determined survival rates under conditions of nutrient deprivation. We used scanning electron microscopy to examine end plate porosity of discs with NCs and those with MNPCs. Nutrientmetabolite profiles and cell viability were calculated as a function of cell density and disc size in a consumption/ diffusion mathematical model.Results. NCs were more active metabolically and more susceptible to nutrient deprivation than were MNPCs. Hypoxia increased rates of glycolysis in NCs but not in MNPCs. Higher end plate porosity in discs with NCs suggested greater nutrient supply in keeping with higher nutritional demands. Mathematical simulations and experiments using an analog disc diffusion chamber indicated that a fall in nutrient concentrations resulting from increased diffusion distance during growth and/or a fall in blood supply through end plate changes could instigate NC disappearance.Conclusion. NCs demand more energy and are less resistant to nutritional stress than MNPCs, which may shed light on the fate of NCs in humans. This provides important information about prospective NC tissue engineering approaches.The intervertebral discs are cartilaginous structures interspersed between the vertebral bodies, providing flexibility to the spinal column. They consist of 3 regions: the outer annulus fibrosus (AF) surrounding the inner nucleus pulposus (NP) and a thin hyaline cartilaginous end plate lying between the disc and the adjacent vertebral bodies. The AF and NP differ in developmental origin, with the annulus arising from the mesenchyme and the nucleus from the notochord (1,2). During development the highly hydrated NP is populated by clusters of large vacuolated notochordal cells (NCs) of distinct molecular phenotype (2,3). In humans and some other species (e.g., cattle, chondrodystrophoid dogs) but not in others (e.g., rodents, pigs), NCs disappear before maturity to be replaced by chondrocyte-like cells of unknown provenance (here called mature NP cells [MNPCs]), which synthesize a more collagenous and less hydrated matrix (1,4-6).

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Mitochondrial gene‐knockout (ρ⁰) cells: A versatile model for exploring the secrets of trans‐plasma membrane electron transport

Cited by 38 publications

References 23 publications

Ascorbic Acid Uptake and Regulation of Type I Collagen Synthesis in Cultured Vascular Smooth Muscle Cells

Ascorbic Acid Uptake and Regulation of Type I Collagen Synthesis in Cultured Vascular Smooth Muscle Cells

Calorie restriction up-regulates the plasma membrane redox system in brain cells and suppresses oxidative stress during aging

Notochordal intervertebral disc cells: Sensitivity to nutrient deprivation

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Mitochondrial gene‐knockout (ρ0) cells: A versatile model for exploring the secrets of trans‐plasma membrane electron transport

Cited by 38 publications

References 23 publications

Ascorbic Acid Uptake and Regulation of Type I Collagen Synthesis in Cultured Vascular Smooth Muscle Cells

Ascorbic Acid Uptake and Regulation of Type I Collagen Synthesis in Cultured Vascular Smooth Muscle Cells

Calorie restriction up-regulates the plasma membrane redox system in brain cells and suppresses oxidative stress during aging

Notochordal intervertebral disc cells: Sensitivity to nutrient deprivation

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Mitochondrial gene‐knockout (ρ⁰) cells: A versatile model for exploring the secrets of trans‐plasma membrane electron transport