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Di Lorenzo R, Di Lorenzo V, Di Serio T, Marzocchi A, Ricci L, Vardaro E, Greco G, Maisto M, Grumetto L, Piccolo V, Morelli E, Laneri S. Phenylalanine Butyramide: A Butyrate Derivative as a Novel Inhibitor of Tyrosinase. Int J Mol Sci 2024; 25:7310. [PMID: 39000417 PMCID: PMC11242249 DOI: 10.3390/ijms25137310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/25/2024] [Accepted: 06/27/2024] [Indexed: 07/16/2024] Open
Abstract
Metabolites resulting from the bacterial fermentation of dietary fibers, such as short-chain fatty acids, especially butyrate, play important roles in maintaining gut health and regulating various biological effects in the skin. However, butyrate is underutilized due to its unpleasant odor. To circumvent this organoleptic unfavorable property, phenylalanine butyramide (PBA), a butyrate precursor, has been synthesized and is currently available on the market. We evaluated the inhibition of mushroom tyrosinase by butyrate and PBA through in vitro assays, finding IC50 values of 34.7 mM and 120.3 mM, respectively. Docking calculations using a homology model of human tyrosinase identified a putative binding mode of PBA into the catalytic site. The anti-aging and anti-spot efficacy of topical PBA was evaluated in a randomized, double-blind, parallel-arm, placebo-controlled clinical trial involving 43 women affected by photo-damage. The results of this study showed that PBA significantly improved skin conditions compared to the placebo and was well tolerated. Specifically, PBA demonstrated strong skin depigmenting activity on both UV and brown spots (UV: -12.7% and -9.9%, Bs: -20.8% and -17.7% after 15 and 30 days, respectively, p < 0.001). Moreover, PBA brightened and lightened the skin (ITA°: +12% and 13% after 15 and 30 days, respectively, p < 0.001). Finally, PBA significantly improved skin elasticity (Ua/Uf: +12.4% and +32.3% after 15 and 30 days, respectively, p < 0.001) and firmness (Uf: -3.2% and -14.9% after 15 and 30 days, respectively, p < 0.01).
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Affiliation(s)
- Ritamaria Di Lorenzo
- Department of Pharmacy, Università degli Studi di Napoli Federico II, 80131 Naples, Italy
| | - Vincenzo Di Lorenzo
- Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Müegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Teresa Di Serio
- Department of Pharmacy, Università degli Studi di Napoli Federico II, 80131 Naples, Italy
| | - Adua Marzocchi
- Department of Pharmacy, Università degli Studi di Napoli Federico II, 80131 Naples, Italy
| | - Lucia Ricci
- Department of Pharmacy, Università degli Studi di Napoli Federico II, 80131 Naples, Italy
| | - Eleonora Vardaro
- Department of Pharmacy, Università degli Studi di Napoli Federico II, 80131 Naples, Italy
| | - Giovanni Greco
- Department of Pharmacy, Università degli Studi di Napoli Federico II, 80131 Naples, Italy
| | - Maria Maisto
- Department of Pharmacy, Università degli Studi di Napoli Federico II, 80131 Naples, Italy
| | - Lucia Grumetto
- Department of Pharmacy, Università degli Studi di Napoli Federico II, 80131 Naples, Italy
| | - Vincenzo Piccolo
- Department of Pharmacy, Università degli Studi di Napoli Federico II, 80131 Naples, Italy
| | - Elena Morelli
- Department of Pharmacy, Università degli Studi di Napoli Federico II, 80131 Naples, Italy
| | - Sonia Laneri
- Department of Pharmacy, Università degli Studi di Napoli Federico II, 80131 Naples, Italy
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Castro PR, Bittencourt LFF, Larochelle S, Andrade SP, Mackay CR, Slevin M, Moulin VJ, Barcelos LS. GPR43 regulates sodium butyrate-induced angiogenesis and matrix remodeling. Am J Physiol Heart Circ Physiol 2021; 320:H1066-H1079. [PMID: 33356962 DOI: 10.1152/ajpheart.00515.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 12/04/2020] [Indexed: 12/26/2022]
Abstract
Butyrate is a short-chain fatty acid (SCFA) derived from microbiota and is involved in a range of cell processes in a concentration-dependent manner. Low concentrations of sodium butyrate (NaBu) were shown to be proangiogenic. However, the mechanisms associated with these effects are not yet fully known. Here, we investigated the contribution of the SCFA receptor GPR43 in the proangiogenic effects of local treatment with NaBu and its effects on matrix remodeling using the sponge-induced fibrovascular tissue model in mice lacking the Gpr43 gene (Gpr43-KO) and the wild-type (WT) mice. We demonstrated that NaBu (0.2 mM intraimplant) treatment enhanced the neovascularization process, blood flow, and VEGF levels in a GPR43-dependent manner in the implants. Moreover, NaBu was able to modulate matrix remodeling aspects of the granulation tissue such as proteoglycan production, collagen deposition, and α-smooth muscle actin (α-SMA) expression in vivo, besides increasing transforming growth factor (TGF)-β1 levels in the fibrovascular tissue, in a GPR43-dependent manner. Interestingly, NaBu directly stimulated L929 murine fibroblast migration and TGF-β1 and collagen production in vitro. GPR43 was found to be expressed in human dermal fibroblasts, myofibroblasts, and endothelial cells. Overall, our findings evidence that the metabolite-sensing receptor GPR43 contributes to the effects of low dose of NaBu in inducing angiogenesis and matrix remodeling during granulation tissue formation. These data provide important insights for the proposition of new therapeutic approaches based on NaBu, beyond the highly explored intestinal, anti-inflammatory, and anticancer purposes, as a local treatment to improve tissue repair, particularly, by modulating granulation tissue components.NEW & NOTEWORTHY Our data show the contribution of the metabolite-sensing receptor GPR43 in the effects of low dose of sodium butyrate (NaBu) on stimulating angiogenesis and extracellular matrix remodeling in a model of granulation tissue formation in mice. We also show that human dermal fibroblasts, myofibroblasts, and endothelial cells express the receptor GPR43. These data provide important insights for the use of NaBu in local therapeutic approaches applicable to tissue repair in sites other than the intestine.
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Affiliation(s)
- Pollyana Ribeiro Castro
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Lucas Felipe Fernandes Bittencourt
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Sébastien Larochelle
- Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Centre de recherche du CHU de Québec-Université Laval, Quebec, Canada
| | - Silvia Passos Andrade
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | | | - Mark Slevin
- School of Healthcare Science, GMBC, Manchester Metropolitan University, Manchester, United Kingdom
| | - Véronique J Moulin
- Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Centre de recherche du CHU de Québec-Université Laval, Quebec, Canada
- Department of Surgery, Faculty of Medicine, Université Laval, Quebec, Canada
| | - Lucíola Silva Barcelos
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
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Negari IP, Keshari S, Huang CM. Probiotic Activity of Staphylococcus epidermidis Induces Collagen Type I Production through FFaR2/p-ERK Signaling. Int J Mol Sci 2021; 22:ijms22031414. [PMID: 33572500 PMCID: PMC7866835 DOI: 10.3390/ijms22031414] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 01/07/2021] [Accepted: 01/27/2021] [Indexed: 12/19/2022] Open
Abstract
Collagen type I is a key structural component of dermis tissue and is produced by fibroblasts and the extracellular matrix. The skin aging process, which is caused by intrinsic or extrinsic factors, such as natural aging or free radical exposure, greatly reduces collagen expression, thereby leading to obstructed skin elasticity. We investigated the effective fermentation of Cetearyl isononanoate (CIN), a polyethylene glycol (PEG) analog, as a carbon source with the skin probiotic bacterium Staphylococcus epidermidis (S.epidermidis) or butyrate, as their fermentation metabolites could noticeably restore collagen expression through phosphorylated extracellular signal regulated kinase (p-ERK) activation in mouse fibroblast cells and skin. Both the in vitro and in vivo knockdown of short-chain fatty acid (SCFA) or free fatty acid receptor 2 (FFaR2) considerably blocked the probiotic effect of S. epidermidis on p-ERK-induced collagen type I induction. These results demonstrate that butyric acid (BA) in the metabolites of fermenting skin probiotic bacteria mediates FFaR2 to induce the synthesis of collagen through p-ERK activation. We hereby imply that metabolites from the probiotic S. epidermidis fermentation of CIN as a potential carbon source could restore impaired collagen in the dermal extracellular matrix (ECM), providing integrity and elasticity to skin.
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Affiliation(s)
- Indira Putri Negari
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan 32001, Taiwan;
| | - Sunita Keshari
- Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan;
| | - Chun-Ming Huang
- Department of Biomedical Sciences and Engineering, National Central University, Taoyuan 32001, Taiwan;
- Correspondence: ; Tel.: +886-3-422-7151 (ext. 36101); Fax: +886-3-425-3427
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Wątor E, Rutkiewicz M, Weiss MS, Wilk P. Co‐expression with chaperones can affect protein 3D structure as exemplified by loss‐of‐function variants of human prolidase. FEBS Lett 2020; 594:3045-3056. [DOI: 10.1002/1873-3468.13877] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/19/2020] [Accepted: 06/23/2020] [Indexed: 02/06/2023]
Affiliation(s)
- Elżbieta Wątor
- Macromolecular Crystallography Helmholtz‐Zentrum Berlin für Materialien und Energie Berlin Germany
| | - Maria Rutkiewicz
- Macromolecular Crystallography Helmholtz‐Zentrum Berlin für Materialien und Energie Berlin Germany
| | - Manfred S. Weiss
- Macromolecular Crystallography Helmholtz‐Zentrum Berlin für Materialien und Energie Berlin Germany
| | - Piotr Wilk
- Macromolecular Crystallography Helmholtz‐Zentrum Berlin für Materialien und Energie Berlin Germany
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Sodium butyrate protects against high-fat diet-induced oxidative stress in rat liver by promoting expression of nuclear factor E2-related factor 2. Br J Nutr 2020; 122:400-410. [PMID: 31204637 DOI: 10.1017/s0007114519001399] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Oxidative stress is closely related to metabolic disorders, which can lead to various diseases. Nuclear factor E2-related factor 2 (Nrf2) is a central regulator of oxidative stress. Sodium butyrate (NaB) has been shown to alleviate oxidative stress and insulin resistance, yet how Nrf2 is involved in the action of NaB remains unclear. In the present study, rats were rendered obese by feeding a high-fat diet for 9 weeks. NaB (300 mg/kg), which was gavaged every 2 d for 7 weeks, significantly alleviated high-fat diet-induced oxidative stress and insulin resistance. Additionally, the insulin signalling pathway in the liver was activated by NaB, associated with significant activation of Nrf2, superoxide dismutase and glutathione. Furthermore, hepatic up-regulation of Nrf2 in NaB-treated rats was associated with reduced protein content of histone deacetylase 1 and increased histone H3 acetyl K9 (H3K9Ac) modification on the Nrf2 promoter. The actions of NaB were completely abolished when Nrf2 was knocked down in vitro. Taken together, NaB acts as a histone deacetylase inhibitor to up-regulate Nrf2 expression with enhanced H3K9Ac modification on its promoter. NaB-induced Nrf2 activation stimulates transcription of downstream antioxidant enzymes, thus contributing to the amelioration of high-fat diet-induced oxidative stress and insulin resistance.
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Karna E, Szoka L, Huynh TYL, Palka JA. Proline-dependent regulation of collagen metabolism. Cell Mol Life Sci 2020; 77:1911-1918. [PMID: 31740988 PMCID: PMC7228914 DOI: 10.1007/s00018-019-03363-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 10/17/2019] [Accepted: 10/30/2019] [Indexed: 12/27/2022]
Abstract
This review is focused on recent data on the role of proline (Pro) in collagen biosynthesis and cellular metabolism. It seems obvious that one of the main substrates for collagen biosynthesis Pro is required to form collagen molecule. The question raised in this review is whether the Pro for collagen biosynthesis is synthesized "de novo", comes directly from degraded proteins or it is converted from other amino acids. Recent data provided evidence that extracellular Pro (added to culture medium) had significant, but relatively little impact on collagen biosynthesis in fibroblasts (the main collagen synthesized cells) cultured in the presence of glutamine (Gln). However, extracellular Pro drastically increased collagen biosynthesis in the cells cultured in Gln-free medium. It suggests that Pro availability determines the rate of collagen biosynthesis and demand for Pro in fibroblasts is predominantly met by conversion from Gln. The potential mechanism of this process as well as possible implication of this knowledge in pharmacotherapy of connective tissue diseases is discussed in this review.
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Affiliation(s)
- Ewa Karna
- Department of Medicinal Chemistry, Medical University of Bialystok, Mickiewicza 2 D, 15-222, Białystok, Poland
| | - Lukasz Szoka
- Department of Medicinal Chemistry, Medical University of Bialystok, Mickiewicza 2 D, 15-222, Białystok, Poland
| | - Thi Yen Ly Huynh
- Department of Medicinal Chemistry, Medical University of Bialystok, Mickiewicza 2 D, 15-222, Białystok, Poland
| | - Jerzy A Palka
- Department of Medicinal Chemistry, Medical University of Bialystok, Mickiewicza 2 D, 15-222, Białystok, Poland.
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Zareba I, Palka J. Prolidase-proline dehydrogenase/proline oxidase-collagen biosynthesis axis as a potential interface of apoptosis/autophagy. Biofactors 2016; 42:341-8. [PMID: 27040799 DOI: 10.1002/biof.1283] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 03/04/2016] [Indexed: 12/20/2022]
Abstract
Prolidase is a cytosolic imidodipeptidase that specifically splits imidodipeptides with C-terminal proline or hydroxyproline. The enzyme plays an important role in the recycling of proline from imidodipeptides for resynthesis of collagen and other proline-containing proteins. The mechanism of prolidase-dependent regulation of collagen biosynthesis was found at both transcriptional and post-transcriptional level. The increase in the enzyme activity is due to its phosphorylation on serine/threonine residues. Prolidase-dependent transcriptional regulation of collagen biosynthesis was found at the level of NF-κB, known inhibitor of type I collagen gene expression. Proline dehydrogenase/proline oxidase (PRODH/POX) is flavin-dependent enzyme associated with the inner mitochondrial membrane. The enzyme catalyzes conversion of proline into Δ(1) -pyrroline-5-carboxylate (P5C), during which reactive oxygen species (ROS) are produced, inducing intrinsic and extrinsic apoptotic pathways. Alternatively, under low glucose stress, PRODH/POX activation produces ATP for energy supply and survival. Of special interest is that PRODH/POX gene is induced by P53 and peroxisome proliferator-activated gamma receptor (PPARγ). Among down-regulators of PRODH/POX is an oncogenic transcription factor c-MYC and miR-23b*. On the other hand, PRODH/POX suppresses HIF-1α transcriptional activity, the MAPK pathway, cyclooxygenase-2, epidermal growth factor receptor and Wnt/b-catenin signaling. PRODH/POX expression is often down-regulated in various tumors, limiting mitochondrial proline utilization to P5C. It is accompanied by increased cytoplasmic level of proline. Proline availability for PRODH/POX-dependent ATP or ROS generation depends on activity of prolidase and utilization of proline in process of collagen biosynthesis. Therefore, Prolidase-PRODH/POX-Collagen Biosynthesis axis may represent potential interface that regulate apoptosis and survival. © 2016 BioFactors, 42(4):341-348, 2016.
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Affiliation(s)
- Ilona Zareba
- Department of Medicinal Chemistry, Medical University of Bialystok, Bialystok, Poland
| | - Jerzy Palka
- Department of Medicinal Chemistry, Medical University of Bialystok, Bialystok, Poland
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Szoka L, Karna E, Morka RP, Palka JA. Enalapril stimulates collagen biosynthesis through prolidase-dependent mechanism in cultured fibroblasts. Naunyn Schmiedebergs Arch Pharmacol 2015; 388:677-83. [PMID: 25772062 PMCID: PMC4438220 DOI: 10.1007/s00210-015-1114-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/04/2015] [Indexed: 12/21/2022]
Abstract
The mechanism of a lower incidence of dermatological manifestations in patients treated with enalapril compared to patients treated with other ACE-inhibitors, e.g., captopril, is not known. The finding that prolidase plays an important role in collagen biosynthesis and that some angiotensin-converting enzyme inhibitors affect prolidase activity led us to evaluate its effect on collagen biosynthesis in cultured human skin fibroblasts. Since insulin-like growth factor (IGF-I) and transforming growth factor beta 1 (TGF-β1) are the most potent stimulators of both collagen biosynthesis and prolidase activity, and prolidase is regulated by β1 integrin signaling, the effect of enalapril and enalaprilat on IGF-IR, TGF-β1, and β1 integrin receptor expressions was evaluated. Cells were treated with milimolar concentrations (0.3 and 0.5 mM) of enalapril and enalaprilat for 24 h. The activity of prolidase was determined by colorimetic assay. Collagen biosynthesis was evaluated by radiometric assay. Expression of signaling proteins was evaluated using Western blot. It was found that enalapril- and enalaprilat-dependent increase in prolidase activity and expression was accompanied by parallel increase in collagen biosynthesis. The exposure of the cells to 0.5 mM enalapril and enalaprilat contributed to increase in IGF-IR and α2β1 integrin receptor as well as TGF-β1 and NF-κB p65 expressions. Enalapril- and enalaprilat-dependent increase of collagen biosynthesis in fibroblasts results from increase of prolidase activity and expression, which may undergo through activation of α2β1 integrin and IGF-IR signaling as well as upregulation of TGF-β1 and NF-κB p65, the inhibitor of collagen gene expression.
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Affiliation(s)
- Lukasz Szoka
- Department of Medicinal Chemistry, Medical University in Bialystok, Mickiewicza 2 D, 15-222 Bialystok, Poland
| | - Ewa Karna
- Department of Medicinal Chemistry, Medical University in Bialystok, Mickiewicza 2 D, 15-222 Bialystok, Poland
| | - Renata Pawlak Morka
- Department of Medicinal Chemistry, Medical University in Bialystok, Mickiewicza 2 D, 15-222 Bialystok, Poland
| | - Jerzy A. Palka
- Department of Medicinal Chemistry, Medical University in Bialystok, Mickiewicza 2 D, 15-222 Bialystok, Poland
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The mechanism of hydralazine-induced collagen biosynthesis in cultured fibroblasts. Naunyn Schmiedebergs Arch Pharmacol 2013; 386:303-9. [PMID: 23344524 PMCID: PMC3597333 DOI: 10.1007/s00210-013-0836-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/14/2013] [Indexed: 11/26/2022]
Abstract
The finding that hydralazine (HYD) affects collagen metabolism led us to investigate the mechanism of its action on collagen biosynthesis, prolidase expression and activity, expression of α2β1 integrin, insulin-like growth factor-I receptor (IGF-IR), focal adhesion kinase (FAK), mitogen-activated protein (MAP) kinases (ERK1, ERK2), and transcription factors hypoxia-inducible factor-1α (HIF-1α) and nuclear factor-κB p65 (NF-κB p65) in human dermal fibroblasts. Confluent fibroblasts were treated with micromolar concentrations (50–500 μM) of HYD for 24 h. HYD had no influence on cell viability. It was found that HYD-dependent increase in collagen biosynthesis was accompanied by a parallel increase in prolidase activity and expression, HIF-1α expression, and decrease in DNA biosynthesis, compared to untreated cells. Since collagen biosynthesis and prolidase activity are regulated by a signal induced by activated α2β1 integrin receptor as well as IGF-IR, the expression of these receptors was measured by Western immunoblot analysis. The exposure of the cells to HYD contributed to the increase in IGF-IR expression without any effect on α2β1 integrin receptor and FAK expressions. It was accompanied by a decrease in expression of MAP kinases and NF-κB p65, the known inhibitor of collagen gene expression. The data suggest that the HYD-dependent increase of collagen biosynthesis in cultured human skin fibroblasts results from activation of IGF-IR expression and prolidase activity and downregulation of NF-κB p65.
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Chen N, Reith MEA. Substrates and inhibitors display different sensitivity to expression level of the dopamine transporter in heterologously expressing cells. J Neurochem 2007; 101:377-88. [PMID: 17250655 DOI: 10.1111/j.1471-4159.2006.04384.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The use of heterologous expression systems for studying dopamine (DA) transporter (DAT) function has provided important information corroborating and complementing in situ obtained knowledge. Preliminary experiments with human embryonic kidney cells (HEK293) heterologously expressing varying amounts of DAT suggested fluctuations in the potency of cocaine in inhibiting DA uptake and led to the present systematic assessment of the impact of the density of DAT on its function. Transiently expressing intact HEK293 cells, transfected with increasing amounts of DAT cDNA, displayed increasing levels of surface DAT, binding of the cocaine analog [(3)H]2beta-carbomethoxy-3beta-(4-fluorophenyl)tropane ([(3)H]CFT), and uptake of [(3)H]DA, [(3)H]N-methyl-4-phenylpyridinium ([(3)H]MPP(+)), [(3)H]norepinephrine, and [(3)H]serotonin. However, the amount of DAT cDNA and the DAT expression level required to produce 50% of maximal activity was threefold higher for CFT binding than for DA uptake. Increased DAT expression was accompanied by weakened potency in inhibiting [(3)H]DA uptake for cocaine, CFT, benztropine, and its analog JHW025, GBR 12909 and mazindol; their potency in inhibiting [(3)H]CFT binding was unaffected. Inhibition of uptake by the substrates DA, m-tyramine, d-amphetamine, or MPP(+) was also unaffected. Increasing DAT in stably expressing HEK293 cells by stimulation of gene expression with sodium butyrate also decreased the uptake inhibitory potency of a number of the above blockers without affecting the interaction between substrates and DAT. The present results prompt discussion of models explaining how factors regulating DAT expression at the plasma membrane can regulate DAT function and pharmacology.
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Affiliation(s)
- Nianhang Chen
- Department of Psychiatry, Millhauser Laboratories, New York University School of Medicine, New York, New York 10016, USA
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