Effect of α-melanocyte-stimulating hormone on tyrosinase activity in hair follicular and epidermal melanocytes of the mouse

1988 ◽  
Vol 119 (3) ◽  
pp. 517-522 ◽  
Author(s):  
P. Seechurn ◽  
S. A. Burchill ◽  
A. J. Thody
Keyword(s):  
Tyrosinase Activity ◽  
In Vitro Experiments ◽  
Dorsal Skin ◽  
Wild Type ◽  
Melanocyte Stimulating Hormone ◽  
Tyrosinase Expression ◽  
In Vivo Administration ◽  
Agouti Gene

ABSTRACT In this study, the effect of α-MSH on tyrosinase activity was compared in epidermal and hair follicular melanocytes of mice. It had no effect on epidermal tyrosinase activity in dorsal skin from neonatal non-agouti black mice (C57BL/6J) in both in-vivo and in-vitro experiments. Theophylline and 8-bromocyclic (c)AMP were similarly without effect in in-vitro experiments. In-vivo administration of α-MSH and theophylline for 7 days was also without effect on epidermal tyrosinase activity in ear skin of adult non-agouti mice, and the same was true for α-MSH in wild-type agouti mice. Activation of the epidermal melanocytes in the non-agouti and wild-type agouti mice with ultraviolet radiation also failed to bring about a response to α-MSH and to theophylline in the case of the former. No tyrosinase activity was detected in the epidermis of viable yellow mice (C3H-HeAvy), but, as shown previously, tyrosinase activity was present in the hair follicle when the hair was actively growing and was increased in those mice given either α-MSH or theophylline. α-MSH and theophylline had no such effects on hair follicular tyrosinase activity in the non-agouti mice. The present results suggest that α-MSH- and cAMP-dependent mechanisms have little or no importance in the regulation of tyrosinase expression in mouse epidermal melanocytes. α-MSH may, however, regulate tyrosinase expression in hair follicular melanocytes, but even in these melanocytes its action may be restricted to mice that express the agouti gene. J. Endocr. (1988) 119, 517–522

scholarly journals Uranium Reduction by Desulfovibrio desulfuricans Strain G20 and a Cytochrome c3 Mutant

2002 ◽  
Vol 68 (6) ◽  
pp. 3129-3132 ◽  
Author(s):  
Rayford B. Payne ◽  
Darren M. Gentry ◽  
Barbara J. Rapp-Giles ◽  
Laurence Casalot ◽  
Judy D. Wall
Keyword(s):  
Electron Donor ◽  
Desulfovibrio Desulfuricans ◽  
Desulfovibrio Vulgaris ◽  
In Vitro Experiments ◽  
Wild Type ◽  
Cytochrome C3 ◽  
Uranium Reduction

ABSTRACT Previous in vitro experiments with Desulfovibrio vulgaris strain Hildenborough demonstrated that extracts containing hydrogenase and cytochrome c 3 could reduce uranium(VI) to uranium(IV) with hydrogen as the electron donor. To test the involvement of these proteins in vivo, a cytochrome c 3 mutant of D. desulfuricans strain G20 was assayed and found to be able to reduce U(VI) with lactate or pyruvate as the electron donor at rates about one-half of those of the wild type. With electrons from hydrogen, the rate was more severely impaired. Cytochrome c 3 appears to be a part of the in vivo electron pathway to U(VI), but additional pathways from organic donors can apparently bypass this protein.

scholarly journals PGI synthase overexpression protects against bleomycin-induced mortality and is associated with increased Nqo 1 expression

2011 ◽  
Vol 301 (4) ◽  
pp. L615-L622 ◽  
Author(s):  
Weisong Zhou ◽  
Dustin R. Dowell ◽  
Mark W. Geraci ◽  
Timothy S. Blackwell ◽  
Robert D. Collins ◽  
...  
Keyword(s):  
Airway Epithelium ◽  
Death Rate ◽  
Treatment Strategies ◽  
Oxygen Species ◽  
In Vitro Experiments ◽  
Wild Type ◽  
Potential Therapeutic Target ◽  
First Time

The mortality rate for acute lung injury (ALI) is reported to be between 35–40%, and there are very few treatment strategies that improve the death rate from this condition. Previous studies have suggested that signaling through the prostaglandin (PG) I2 receptor may protect against bleomycin-induced ALI in mice. We found that mice that overexpress PGI synthase (PGIS) in the airway epithelium were significantly protected against bleomycin-induced mortality and had reduced parenchymal consolidation, apoptosis of lung tissue, and generation of F2-isoprostanes compared with littermate wild-type controls. In addition, we show for the first time in both in vivo and in vitro experiments that PGI2 induced the expression of NADP (H): quinoneoxidoreductase 1 (Nqo 1), an enzyme that prevents the generation of reactive oxygen species. PGI2 induction of Nqo 1 provides a possible novel mechanism by which this prostanoid protects against bleomycin-induced mortality and identifies a potential therapeutic target for human ALI.

scholarly journals In Vivo Evidence for Instability of Episomal Human Immunodeficiency Virus Type 1 cDNA

2005 ◽  
Vol 79 (8) ◽  
pp. 5203-5210 ◽  
Author(s):  
Mark Sharkey ◽  
Karine Triques ◽  
Daniel R. Kuritzkes ◽  
Mario Stevenson
Keyword(s):  
Viral Replication ◽  
In Vitro Experiments ◽  
Plasma Viremia ◽  
Wild Type ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Current regimens for the management of human immunodeficiency virus type 1 (HIV-1) infection suppress plasma viremia to below detectable levels for prolonged intervals. Nevertheless, there is a rapid resumption in plasma viremia if therapy is interrupted. Attempts to characterize the extent of viral replication under conditions of potent suppression and undetectable plasma viremia have been hampered by a lack of convenient assays that can distinguish latent from ongoing viral replication. Using episomal viral cDNA as a surrogate for ongoing replication, we previously presented evidence that viral replication persists in the majority of infected individuals with a sustained aviremic status. The labile nature of viral episomes and hence their validity as surrogate markers of ongoing replication in individuals with long-term-suppressed HIV-1 infection have been analyzed in short-term in vitro experiments with conflicting results. Since these in vitro experiments do not shed light on the long-term in vivo dynamics of episomal cDNA or recapitulate the natural targets of infection in vivo, we have analyzed the dynamics of episomal cDNA turnover in vivo by following the emergence of an M184V polymorphism in plasma viral RNA, in episomal cDNA, and in proviral DNA in patients on suboptimal therapies. We demonstrate that during acquisition of drug resistance, wild-type episomal cDNAs are replaced by M184V-harboring episomes. Importantly, a complete replacement of wild-type episomes with M184V-containing episomes occurred while proviruses remained wild type. This indicates that episomal cDNAs are turned over by degradation rather than through death or tissue redistribution of the infected cell itself. Therefore, evolution of episomal viral cDNAs is a valid surrogate of ongoing viral replication in HIV-1-infected individuals.

scholarly journals Evaluation of 2′-Deoxy-2′-Flouro-5-Methyl-1-β-d-Arabinofuranosyluracil as a Potential Gene Imaging Agent for HSV-tk Expression In Vivo

2002 ◽  
Vol 1 (2) ◽  
pp. 153535002002021
Author(s):  
Mian M. Alauddin ◽  
Atranik Shahinian ◽  
Erlinda M. Gordon ◽  
Peter S. Conti
Keyword(s):  
Emission Tomography ◽  
In Vivo Studies ◽  
In Vitro Experiments ◽  
Tumor Uptake ◽  
Wild Type ◽  
Positron Emission ◽  
Additional Tumor ◽  
Ht 29

2′-Deoxy-2′-flouro-5-methyl-1-β-d-arabinofuranosyluracil (FMAU) has been evaluated in HT-29 cells as a potential positron emission tomography (PET) radiotracer for imaging HSV-tk gene expression in vivo. In vitro experiments demonstrate that the accumulation of [14C]-FMAU in HSV-tk-expressing cells is 2.4-fold ( p < .02), 4.0-fold ( p < .001), and 5.3-fold ( p < .001) higher than the wild-type cells at 1, 3, and 5 hr, respectively. In vivo studies revealed that the tumor uptake in HSV-tk-expressing cells was 2.3-fold ( p < .001), 3.0-fold ( p < .001), and 5.5-fold ( p < .001) higher than the control cells at 1, 2, and 5 hr, respectively. FMAU was found to be more sensitive compared to our earlier studies using 9-[(3-18F-fluoro-1-hydroxy-2-propoxy)methyl]-guanine ([18F]-FHPG) and 9-(4-[18F]-fluoro-3-hydroxy-methylbutyl)guanine ([18F]-FHBG) in the same cell lines, although, the specificity was less than FHBG. These results suggest that while FMAU labeled with PET isotopes may be useful for imaging HSV-tk-expressing tumors in vivo, multitracer studies across additional tumor models are necessary in order to identify an optimal PET radiotracer.

Anticoagulant Properties of Three Mucopolysaccharides Used in Rheumatology

1983 ◽  
Vol 50 (03) ◽  
pp. 652-655 ◽  
Author(s):  
F Bauer ◽  
P Schulz ◽  
G Reber ◽  
C A Bouvier
Keyword(s):  
Factor Xa ◽  
Degenerative Joint Disease ◽  
Joint Disease ◽  
Thrombin Time ◽  
Coagulation Tests ◽  
Amplification System ◽  
Relative Potencies ◽  
In Vivo Administration

SummaryThree mucopolysaccharides (MPS) used in the treatment of degenerative joint disease were compared to heparin to establish their relative potencies on 3 coagulation tests, the aPTT, the antifactor X a activity and the dilute thrombin time. One of the compounds, Arteparon®, was one fourth as potent as heparin on the aPTT, but had little or no influence on the 2 other tests. Further in vitro studies suggested that Arteparon® acted at a higher level than factor Xa generation in the intrinsic amplification system and that its effect was independent of antithrombin III. In vivo administration of Arteparon® confirmed its anticoagulant properties, which raises the question of the clinical use of this MPS.

scholarly journals Arabidopsis Disulfide Reductase, Trx-h2, Functions as an RNA Chaperone under Cold Stress

2021 ◽  
Vol 11 (15) ◽  
pp. 6865
Author(s):  
Eun Seon Lee ◽  
Joung Hun Park ◽  
Seong Dong Wi ◽  
Ho Byoung Chae ◽  
Seol Ki Paeng ◽  
...  
Keyword(s):  
Cold Stress ◽  
Wild Type ◽  
Rna Chaperone ◽  
E Coli ◽  
Cold Sensitive ◽  
Thioredoxin H ◽  
Functional Rnas

The thioredoxin-h (Trx-h) family of Arabidopsis thaliana comprises cytosolic disulfide reductases. However, the physiological function of Trx-h2, which contains an additional 19 amino acids at its N-terminus, remains unclear. In this study, we investigated the molecular function of Trx-h2 both in vitro and in vivo and found that Arabidopsis Trx-h2 overexpression (Trx-h2OE) lines showed significantly longer roots than wild-type plants under cold stress. Therefore, we further investigated the role of Trx-h2 under cold stress. Our results revealed that Trx-h2 functions as an RNA chaperone by melting misfolded and non-functional RNAs, and by facilitating their correct folding into active forms with native conformation. We showed that Trx-h2 binds to and efficiently melts nucleic acids (ssDNA, dsDNA, and RNA), and facilitates the export of mRNAs from the nucleus to the cytoplasm under cold stress. Moreover, overexpression of Trx-h2 increased the survival rate of the cold-sensitive E. coli BX04 cells under low temperature. Thus, our data show that Trx-h2 performs function as an RNA chaperone under cold stress, thus increasing plant cold tolerance.

scholarly journals Neuroprotective Potential of a Small Molecule RET Agonist in Cultured Dopamine Neurons and Hemiparkinsonian Rats

2021 ◽  
pp. 1-24
Author(s):  
Juho-Matti Renko ◽  
Arun Kumar Mahato ◽  
Tanel Visnapuu ◽  
Konsta Valkonen ◽  
Mati Karelson ◽  
...  
Keyword(s):  
Mapk Signaling ◽  
Dopamine Neurons ◽  
Dopamine Depletion ◽  
Wild Type ◽  
Disease Modifying Therapy ◽  
Immortalized Cells ◽  
Midbrain Dopamine ◽  
6 Hydroxydopamine

Background: Parkinson’s disease (PD) is a progressive neurological disorder where loss of dopamine neurons in the substantia nigra and dopamine depletion in the striatum cause characteristic motor symptoms. Currently, no treatment is able to halt the progression of PD. Glial cell line-derived neurotrophic factor (GDNF) rescues degenerating dopamine neurons both in vitro and in animal models of PD. When tested in PD patients, however, the outcomes from intracranial GDNF infusion paradigms have been inconclusive, mainly due to poor pharmacokinetic properties. Objective: We have developed drug-like small molecules, named BT compounds that activate signaling through GDNF’s receptor, the transmembrane receptor tyrosine kinase RET, both in vitro and in vivo and are able to penetrate through the blood-brain barrier. Here we evaluated the properties of BT44, a second generation RET agonist, in immortalized cells, dopamine neurons and rat 6-hydroxydopamine model of PD. Methods: We used biochemical, immunohistochemical and behavioral methods to evaluate the effects of BT44 on dopamine system in vitro and in vivo. Results: BT44 selectively activated RET and intracellular pro-survival AKT and MAPK signaling pathways in immortalized cells. In primary midbrain dopamine neurons cultured in serum-deprived conditions, BT44 promoted the survival of the neurons derived from wild-type, but not from RET knockout mice. BT44 also protected cultured wild-type dopamine neurons from MPP +-induced toxicity. In a rat 6-hydroxydopamine model of PD, BT44 reduced motor imbalance and could have protected dopaminergic fibers in the striatum. Conclusion: BT44 holds potential for further development into a novel, possibly disease-modifying therapy for PD.

scholarly journals Marliolide Derivative Induces Melanosome Degradation via Nrf2/p62-Mediated Autophagy

2021 ◽  
Vol 22 (8) ◽  
pp. 3995
Author(s):  
Cheong-Yong Yun ◽  
Nahyun Choi ◽  
Jae Un Lee ◽  
Eun Jung Lee ◽  
Ji Young Kim ◽  
...  
Keyword(s):  
Related Factor ◽  
Melanin Pigmentation ◽  
Microtubule Associated Proteins ◽  
Melanocyte Stimulating Hormone ◽  
Associated Proteins ◽  
Autophagy Pathway ◽  
Nrf2 Activator ◽  
Promising Therapeutic Agent

Nuclear factor erythroid 2-related factor 2 (Nrf2), which is linked to autophagy regulation and melanogenesis regulation, is activated by marliolide. In this study, we investigated the effect of a marliolide derivative on melanosome degradation through the autophagy pathway. The effect of the marliolide derivative on melanosome degradation was investigated in α-melanocyte stimulating hormone (α-MSH)-treated melanocytes, melanosome-incorporated keratinocyte, and ultraviolet (UV)B-exposed HRM-2 mice (melanin-possessing hairless mice). The marliolide derivative, 5-methyl-3-tetradecylidene-dihydro-furan-2-one (DMF02), decreased melanin pigmentation by melanosome degradation in α-MSH-treated melanocytes and melanosome-incorporated keratinocytes, evidenced by premelanosome protein (PMEL) expression, but did not affect melanogenesis-associated proteins. The UVB-induced hyperpigmentation in HRM-2 mice was also reduced by a topical application of DMF02. DMF02 activated Nrf2 and induced autophagy in vivo, evidenced by decreased PMEL in microtubule-associated proteins 1A/1B light chain 3B (LC3)-II-expressed areas. DMF02 also induced melanosome degradation via autophagy in vitro, and DMF02-induced melanosome degradation was recovered by chloroquine (CQ), which is a lysosomal inhibitor. In addition, Nrf2 silencing by siRNA attenuated the DMF02-induced melanosome degradation via the suppression of p62. DMF02 induced melanosome degradation in melanocytes and keratinocytes by regulating autophagy via Nrf2-p62 activation. Therefore, Nrf2 activator could be a promising therapeutic agent for reducing hyperpigmentation.

scholarly journals The double-stranded DNA-binding proteins TEBP-1 and TEBP-2 form a telomeric complex with POT-1

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sabrina Dietz ◽  
Miguel Vasconcelos Almeida ◽  
Emily Nischwitz ◽  
Jan Schreier ◽  
Nikenza Viceconte ◽  
...  
Keyword(s):  
Quantitative Proteomics ◽  
Wild Type ◽  
C Elegans ◽  
Double Stranded Dna ◽  
Telomere Sequence ◽  
Proteomics Approach ◽  
Telomeric Protein ◽  
Regulate Telomere Length

AbstractTelomeres are bound by dedicated proteins, which protect them from DNA damage and regulate telomere length homeostasis. In the nematode Caenorhabditis elegans, a comprehensive understanding of the proteins interacting with the telomere sequence is lacking. Here, we harnessed a quantitative proteomics approach to identify TEBP-1 and TEBP-2, two paralogs expressed in the germline and embryogenesis that associate to telomeres in vitro and in vivo. tebp-1 and tebp-2 mutants display strikingly distinct phenotypes: tebp-1 mutants have longer telomeres than wild-type animals, while tebp-2 mutants display shorter telomeres and a Mortal Germline. Notably, tebp-1;tebp-2 double mutant animals have synthetic sterility, with germlines showing signs of severe mitotic and meiotic arrest. Furthermore, we show that POT-1 forms a telomeric complex with TEBP-1 and TEBP-2, which bridges TEBP-1/-2 with POT-2/MRT-1. These results provide insights into the composition and organization of a telomeric protein complex in C. elegans.

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