Ultraviolet A induces transport of compatible organic osmolytes in human dermal fibroblasts

Warskulat, Ulrich; Brookmann, Stefanie; Felsner, Ingo; Brenden, Heidi; Häussinger, Dieter

doi:10.1111/j.1600-0625.2008.00746.x

Cited by 14 publications

(11 citation statements)

References 43 publications

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“…Interestingly, keratinocytes have been demonstrated to use osmolytes to maintain volume homeostasis [66]. Pathways associated with compatible osmolyte systems, specifically co-transporters, have been documented to be induced in keratinocytes under environmental stress [67], [68]. In contrast, the phenotypes of the TmB and OmB cell lines resemble endothelial (small rounded cell shape) and fibroblast-like (elongated, spindle cell shape) cells, respectively.…”

Section: Discussionmentioning

confidence: 99%

Derivation and Osmotolerance Characterization of Three Immortalized Tilapia (Oreochromis mossambicus) Cell Lines

et al. 2014

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Fish cell cultures are becoming more widely used models for investigating molecular mechanisms of physiological response to environmental challenge. In this study, we derived two immortalized Mozambique tilapia (Oreochromis mossambicus) cell lines from brain (OmB) and lip epithelium (OmL), and compared them to a previously immortalized bulbus arteriosus (TmB) cell line. The OmB and OmL cell lines were generated without or with Rho-associated kinase (ROCK) inhibitor/3T3 feeder layer supplementation. Although both approaches were successful, ROCK inhibitor/feeder layer supplementation was found to offer the advantages of selecting for epithelial-like cell type and decreasing time to immortalization. After immortalization (≥ passage 5), we characterized the proteomes of the newly derived cell lines (OmB and OmL) using LCMS and identified several unique cell markers for each line. Subsequently, osmotolerance for each of the three cell lines following acute exposure to elevated sodium chloride was evaluated. The acute maximum osmotolerance of these tilapia cell lines (>700 mOsm/kg) was markedly higher than that of any other known vertebrate cell line, but was significantly higher in the epithelial-like OmL cell line. To validate the physiological relevance of these tilapia cell lines, we quantified the effects of acute hyperosmotic challenge (450 mOsm/kg and 700 mOsm/kg) on the transcriptional regulation of two enzymes involved in biosynthesis of the compatible organic osmolyte, myo-inositol. Both enzymes were found to be robustly upregulated in all three tilapia cell lines. Therefore, the newly established tilapia cells lines represent valuable tools for studying molecular mechanisms involved in the osmotic stress response of euryhaline fish.

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Section: Discussionmentioning

confidence: 99%

Derivation and Osmotolerance Characterization of Three Immortalized Tilapia (Oreochromis mossambicus) Cell Lines

et al. 2014

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“…In previous reports, keratinocytes and fibroblasts were shown to express specific proteins and transporters to maintain the cellular homeostasis under hyperosmotic conditions [10]–[12]. However, there are no reports of the hyperosmotic effects on melanotic cells.…”

Section: Discussionmentioning

confidence: 99%

“…Keratinocytes maintain cell volume homeostasis by regulating the expression of organic osmolyte transporters [10], [11]. Because organic osmolytes are involved in antioxidant defenses, protein stabilization and stress responses, human dermal fibroblasts sometimes express organic osmolyte transporters, and osmolytes accumulate inside the cells [12].…”

Section: Introductionmentioning

confidence: 99%

“…Because the skin is an organ that is regulated by osmotic stress [8]–[12] and because melanosomes are lysosome-related organelles and their biogenesis could be affected by hyperosmotic stress, it is possible that melanogenesis is regulated by changes in osmotic pressure. In this study, we examined the osmotic effects on melanosome formation and melanin production in human melanoma MNT-1 cells, which are highly pigmented and include well-organized mature melanosomes of stage III and IV.…”

Section: Introductionmentioning

confidence: 99%

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Hyperosmotic Stress Reduces Melanin Production by Altering Melanosome Formation

et al. 2014

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Many tissues of the human body encounter hyperosmotic stress. The effect of extracellular osmotic changes on melanin production has not yet been elucidated. In this study, we determined that hyperosmotic stress induced by organic osmolytes results in reduced melanin production in human melanoma MNT-1 cells. Under hyperosmotic stress, few pigmented mature melanosomes were detected, but there was an increase in swollen vacuoles. These vacuoles were stained with an anti-M6PR antibody that recognizes late endosomal components and with anti-TA99 and anti-HMB45 antibodies, implying that melanosome formation was affected by hyperosmotic stress. Electron microscopic analysis revealed that the M6PR-positive swollen vacuoles were multi-layered and contained melanized granules, and they produced melanin when L-DOPA was applied, indicating that these vacuoles were still capable of producing melanin, but the inner conditions were not compatible with melanin production. The vacuolation phenomenon induced by hyperosmotic conditions disappeared with treatment with the PI3K activator 740 Y-P, indicating that the PI3K pathway is affected by hyperosmotic conditions and is responsible for the proper formation and maturation of melanosomes. The microarray analysis showed alterations of the vesicle organization and transport under hyperosmotic stress. Our findings suggest that melanogenesis could be regulated by physiological conditions, such as osmotic pressure.

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“…Cellular accumulation of betaine is mediated by the osmoregulated betaine/γ-aminobutyric acid (GABA) transporter, designated BGT-1 (Yamauchi et al 1992), which is expressed in kidneys (Kempson and Montrose 2004) and other tissues (Olsen et al 2005;Petronini et al 2000;Warskulat et al 2008). Other osmoregulated mammalian betaine transporters exist that are not specific to betaine (Anas et al 2008;Burg and Ferraris 2008).…”

Section: Betaine and Osmoregulationmentioning

confidence: 98%

Choline and betaine in health and disease

Ueland

2010

J of Inher Metab Disea

467

388

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Choline is an essential nutrient, but is also formed by de novo synthesis. Choline and its derivatives serve as components of structural lipoproteins, blood and membrane lipids, and as a precursor of the neurotransmitter acetylcholine. Pre-and postnatal choline availability is important for neurodevelopment in rodents. Choline is oxidized to betaine that serves as an osmoregulator and is a substrate in the betaine-homocysteine methyltransferase reaction, which links choline and betaine to the folate-dependent one-carbon metabolism. Choline and betaine are important sources of one-carbon units, in particular, during folate deficiency. Choline or betaine supplementation in humans reduces concentration of total homocysteine (tHcy), and plasma betaine is a strong predictor of plasma tHcy in individuals with low plasma concentration of folate and other B vitamins (B₂, B₆, and B₁₂) in combination TT genotype of the methylenetetrahydrofolate reductase 677 C->T polymorphism. The link to one-carbon metabolism and the recent availability of food composition data have motivated studies on choline and betaine as risk factors of chronic diseases previously studied in relation to folate and homocysteine status. High intake and plasma level of choline in the mother seems to afford reduced risk of neural tube defects. Intake of choline and betaine shows no consistent relation to cancer or cardiovascular risk or risk factors, whereas an unfavorable cardiovascular risk factor profile was associated with high choline and low betaine concentrations in plasma. Thus, choline and betaine showed opposite relations with key components of metabolic syndrome, suggesting a disruption of mitochondrial choline oxidation to betaine as part of the mitochondrial dysfunction in metabolic syndrome.

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Ultraviolet A induces transport of compatible organic osmolytes in human dermal fibroblasts

Cited by 14 publications

References 43 publications

Derivation and Osmotolerance Characterization of Three Immortalized Tilapia (Oreochromis mossambicus) Cell Lines

Derivation and Osmotolerance Characterization of Three Immortalized Tilapia (Oreochromis mossambicus) Cell Lines

Hyperosmotic Stress Reduces Melanin Production by Altering Melanosome Formation

Choline and betaine in health and disease

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