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Dive into the research topics where Irén Horkay is active.

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Featured researches published by Irén Horkay.


Journal of Photochemistry and Photobiology B-biology | 2008

Reference genes for quantitative real time PCR in UVB irradiated keratinocytes.

Attila Balogh; György Paragh; Attila Juhász; Tamás Köbling; Dániel Törőcsik; Edit Mikó; V.E. Varga; Gabriella Emri; Irén Horkay; Beáta Scholtz; Éva Remenyik

Real time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) is a sensitive and highly reproducible method often used for determining mRNA levels. To enable proper comparison of gene expression genes expressed at stabile levels within the cells in the studied experimental system need to be identified and used as reference. Ultraviolet B (UVB) radiation is an exogenous carcinogenic stimulus in keratinocytes, and UVB elicited changes have extensively been studied by qRT-PCR, yet a comparison of commonly used reference genes in UVB treatment is lacking. To find the best genes for compensating slight inter-sample variations in keratinocytes in UVB experiments and to understand the potential effects of improper reference gene (RG) selection we have analyzed the mRNA expression of 10 housekeeping genes in neonatal human epidermal keratinocytes (NHEK) after UVB treatment. The biological effect of the used UVB light source was validated by trypane blue exclusion, MTT and comet assays. 20-40mJ/cm(2) dose was chosen for the experiments. The stability of the 10 RGs was assessed by the GeNorm and Normfinder software tools. Regardless of their slightly different algorithm the programs found succinate dehydrogenase complex subunit A (SDHA) to be the best individual RG and SDHA and phosphoglycerate kinase-1 (PGK1) as the most suitable combination. Analysis of the expression of tumor necrosis factor alpha (TNFalpha) and vascular endothelial growth factor (VEGF) found that while the perception of changes in TNF-alpha, a gene undergoing marked upregulation after UVB irradiation is independent of the used RG, changes seen in the more modestly upregulated VEGF are greatly effected by reference gene selection. These findings highlight the importance of reference gene selection in UVB irradiation experiments, and provide evidence that using SDHA or the combination of SDHA and PGK1 as standards could be a reliable method for normalizing qRT-PCR results in keratinocytes after UVB treatment.


Liver International | 2004

Hemochromatosis (HFE) gene mutations and hepatitis C virus infection as risk factors for porphyria cutanea tarda in Hungarian patients

Zsuzsanna Nagy; Ferenc Kószó; Alajos Pár; Gabriella Emri; Irén Horkay; Margit Horányi; O. Karádi; György Rumi; Márta Morvay; V.E. Varga; A. Dobozy; Gyula Mózsik

Aim: It is not clear whether the mutations in hemochromatosis (HFE) gene and hepatitis C virus (HCV) infection act independently in the pathogenesis of porphyria cutanea tarda (PCT). The prevalence of both risk factors varies greatly in different parts of the world. PCT patients from Hungary were evaluated to assess both factors.


Journal of Photochemistry and Photobiology B-biology | 2013

Transfection of pseudouridine-modified mRNA encoding CPD-photolyase leads to repair of DNA damage in human keratinocytes: a new approach with future therapeutic potential

Gábor Boros; Edit Mikó; Hiromi Muramatsu; Drew Weissman; Eszter Emri; Dávid Rózsa; Georgina Nagy; Attila Juhász; István Juhász; Gijsbertus T. J. van der Horst; Irén Horkay; Éva Remenyik; Katalin Karikó; Gabriella Emri

UVB irradiation induces harmful photochemical reactions, including formation of Cyclobutane Pyrimidine Dimers (CPDs) in DNA. Accumulation of unrepaired CPD lesions causes inflammation, premature ageing and skin cancer. Photolyases are DNA repair enzymes that can rapidly restore DNA integrity in a light-dependent process called photoreactivation, but these enzymes are absent in humans. Here, we present a novel mRNA-based gene therapy method that directs synthesis of a marsupial, Potorous tridactylus, CPD-photolyase in cultured human keratinocytes. Pseudouridine was incorporated during in vitro transcription to make the mRNA non-immunogenic and highly translatable. Keratinocytes transfected with lipofectamine-complexed mRNA expressed photolyase in the nuclei for at least 2days. Exposing photolyase mRNA-transfected cells to UVB irradiation resulted in significantly less CPD in those cells that were also treated with photoreactivating light, which is required for photolyase activity. The functional photolyase also diminished other UVB-mediated effects, including induction of IL-6 and inhibition of cell proliferation. These results demonstrate that pseudouridine-containing photolyase mRNA is a powerful tool to repair UVB-induced DNA lesions. The pseudouridine-modified mRNA approach has a strong potential to discern cellular effects of CPD in UV-related cell biological studies. The mRNA-based transient expression of proteins offers a number of opportunities for future application in medicine.


Acta Dermato-venereologica | 2005

Sporotrichoid Cutaneous Mycobacterium Tuberculosis Infection in a Child

Éva Remenyik; Béla Nagy; Mária Kiss; Imre Veres; Mónika Sápy; Irén Horkay; Irén Erdei; J. Hunyadi

Eva Remenyik, Bela Nagy, Maria Kiss, Imre Veres, Monika Sapy, Iren Horkay, Iren Erdei and Janos Hunyadi Departments of Dermatology and, Pediatrics, University of Debrecen, Medical and Health Science Center, University of Debrecen, Nagyerdei korut 98, HU-4012 Debrecen, Hungary and Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary. E-mail: [email protected] Accepted December 22, 2004.


PLOS ONE | 2015

Identification of Cyclobutane Pyrimidine Dimer-Responsive Genes Using UVB-Irradiated Human Keratinocytes Transfected with In Vitro-Synthesized Photolyase mRNA.

Gábor Boros; Edit Mikó; Hiromi Muramatsu; Drew Weissman; Eszter Emri; Gijsbertus T. J. van der Horst; Andrea Szegedi; Irén Horkay; Gabriella Emri; Katalin Karikó; Éva Remenyik

Major biological effects of UVB are attributed to cyclobutane pyrimidine dimers (CPDs), the most common photolesions formed on DNA. To investigate the contribution of CPDs to UVB-induced changes of gene expression, a model system was established by transfecting keratinocytes with pseudouridine-modified mRNA (Ψ-mRNA) encoding CPD-photolyase. Microarray analyses of this model system demonstrated that more than 50% of the gene expression altered by UVB was mediated by CPD photolesions. Functional classification of the gene targets revealed strong effects of CPDs on the regulation of the cell cycle and transcriptional machineries. To confirm the microarray data, cell cycle-regulatory genes, CCNE1 and CDKN2B that were induced exclusively by CPDs were selected for further investigation. Following UVB irradiation, expression of these genes increased significantly at both mRNA and protein levels, but not in cells transfected with CPD-photolyase Ψ-mRNA and exposed to photoreactivating light. Treatment of cells with inhibitors of c-Jun N-terminal kinase (JNK) blocked the UVB-dependent upregulation of both genes suggesting a role for JNK in relaying the signal of UVB-induced CPDs into transcriptional responses. Thus, photolyase mRNA-based experimental platform demonstrates CPD-dependent and -independent events of UVB-induced cellular responses, and, as such, has the potential to identify novel molecular targets for treatment of UVB-mediated skin diseases.


Journal of Photochemistry and Photobiology B-biology | 2018

Ultraviolet radiation-mediated development of cutaneous melanoma: An update

Gabriella Emri; György Paragh; Ágnes Tósaki; Eszter Janka; Sándor Kollár; Csaba Hegedűs; Emese Gellén; Irén Horkay; Gábor Koncz; Éva Remenyik

Ultraviolet (UV) light is absorbed by nucleic acids, proteins or other endogenous chromophores, such as porphyrins, flavins and melanin, triggering biological processes in skin cells. Both UV-induced mutations in melanocytes and changes in the immune microenvironment are understood to play a role in the development of cutaneous melanoma. The degree of UV-induced stress and the protection against this stress are influenced by both intracellular and intercellular molecular interactions. The present review summarizes the known major molecular biological changes induced by UV light in the skin that play a role in melanoma initiation and promotion. Nevertheless, cutaneous melanoma is not a homogenous disease, and the interaction of variable environmental exposure and different genetic susceptibility and other host factors lead to the formation of melanomas with different biological behavior and clinical characteristics. This review highlights the challenges in the understanding of how UV radiation contributes to the formation of cutaneous melanoma, and reviews the new results of photobiology and their link to tumor genetics and tumor immunology with potential implications on melanoma prevention and therapeutic strategies. The information presented here is expected to add clarity to ongoing research efforts in this field to aid the development of novel strategies to prevent and treat melanoma.


Bőrgyógyászati és Venerológiai Szemle | 2013

Az mRNS-alapú génterápia dermatológiai alkalmazásának lehetőségei: fényvédelem újragondolva = Dermatological application of mRNA-based gene therapy : protection from UV-radiation-caused damages

Gábor Boros; Edit Mikó; Irén Horkay; Katalin Karikó; Gabriella Emri; Éva Remenyik

A világszerte növekvô számban jelentkezô UV sugárzás okozta betegségek új megelôzô és terápiás stratégia kifejlesztését indokolják. Az UVB által elôidézett leggyakoribb DNS léziók a ciklobután pirimidin dimerek (CPD), amelyek apoptózishoz, immunszuppresszióhoz, mutációhoz, ezáltal bôrbetegségek kialakulásához vezethetnek. Az élettanilag fontos fehérjék in vitro-szintetizált mRNS által történô expresszálása nagy terápiás lehetôséggel bír. Ennek az új génterápiás technológiának az alkalmazásával sikerült funkcionálisan aktív CPD-specifikus fotoliáz fehérjét kifejezni humán keratinocitákban. Ezen tanulmány összefoglalja, hogy az in vitro-szintetizált mRNS milyen fontos és elônyös eszköze lehet a modern terápiás eljárásoknak.


Archive | 1999

Comet Assay to Study UV-Induced DNA Damage

Éva Remenyik; Csaba Varga; Gabriella Emri; J. Hunyadi; Irén Horkay

The importance of environmental UV radiation is increasing. Its contribution to skin carcinogenesis has been widely accepted and intensively studied. One of the important steps in the biological effects of UV radiation is its DNA damaging effect. It has long been known that UV spectrum is separated in three different regions according to their biologic effect (UVC 100–280, UVB 280–320, UVA 320–410 nm). In the UVB spectrum the cyclobutane pyrimidine dimers and 6-4 photoproduct are the main DNA lesions. In higher wavelengths active oxygen species may be responsible for DNA strand breaks (1).


Journal of Investigative Dermatology | 1990

Formation of DNA Adducts in the Skin of Psoriasis Patients, in Human Skin in Organ Culture, and in Mouse Skin and Lung Following Topical Application of Coal-Tar and Juniper Tar

Bernadette Schoket; Irén Horkay; Ágnes Kósa; László Paldeak; Alan Hewer; Philip L. Grover; David H. Phillips


Metallomics | 2015

Effects of non-toxic zinc exposure on human epidermal keratinocytes†

Eszter Emri; Edit Mikó; Péter Bai; Gábor Boros; Georgina Nagy; Dávid Rózsa; Tamás Juhász; Csaba Hegedűs; Irén Horkay; Éva Remenyik; Gabriella Emri

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Edit Mikó

University of Debrecen

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Eszter Emri

University of Debrecen

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Katalin Karikó

University of Pennsylvania

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