Összes szerző

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Domingos Geraldo

az alábbi absztraktok szerzői között szerepel:

Biró-Gyuris Katinka
Role of the hHv1 proton channel in vascular smooth muscle cells

Aug 30 - szerda

15:30 – 17:00

II. Poszterszekció

P37

Role of the hHv1 proton channel in vascular smooth muscle cells

Katinka Gyuris¹, Geraldo Domingos¹, Éva Korpos² and Zoltán Varga¹

¹ University of Debrecen, Faculty of Medicine, Department of Biophysics and Cell Biology

² University of Debrecen, Faculty of Medicine, Department of Biophysics and Cell Biology, MTA-DE Cell Biology and Signaling Research Group

The hHv1 voltage-dependent proton channel is a passive transporter that selectively transfers protons across the membrane, and thus plays an important role in pH regulation of many cell types. Vascular smooth muscle cells (VSMCs) found in the arterial wall have a resting or contractile phenotype under physiological conditions. When the vessel wall is damaged, the cells switch to a synthetic, migratory and proliferative phenotype, which allows tissue regeneration. Failure of migrating/proliferating cells to switch back to a contractile phenotype induces pathogenic vascular remodelling leading to atherosclerosis.

In our work, we aim to demonstrate the presence of hHv1 on vascular smooth muscle cells and to elucidate the role of the channel in normal and pathological cellular activities through the regulation of intracellular pH. We investigate the role of hHv1 in VSMC survival, differentiation and matrix production.

If hHv1 plays a key role in the pathological activity of VSMCs during atherosclerosis but not in normal function, the channel may become an important pharmacological target to inhibit the pathological activity of VSMCs in atherosclerosis.

To confirm this hypothesis, we performed viability assays using MTT assay, motility experiments using scratch assay method and impedance measurement, PCR and Western blot experiments to detect hHv1, alizarin red staining to visualize the effect on calcified extracellular matrix production, and microscopic studies.

Our results support the hypothesis that hHv1 is expressed in VSMCs and plays a role in their ability to migrate and influences their viability. This conclusion may provide a basis for further experiments to quantify the difference in hHv1 expression between contractile and differentiated proliferative cells and to identify related functional differences.

Domingos Geraldo Jorge
Identification of inhibitors of the human hv1 proton channel

Aug 30 - szerda

15:30 – 17:00

II. Poszterszekció

P40

Identification of inhibitors of the human h_v1 proton channel

Geraldo Domingos¹, Adam Feher¹, Eva Korpos ^1,2, Tibor G. Szanto¹, Martina Piga³, Tihomir Tomasic³, Nace Zidar³, Adrienn Gyongyosi⁴, Judit Kallai⁴, Arpad Lanyi⁴, Ferenc Papp¹, Katinka Gyuris¹, Zoltan Varga¹

1 Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Hungary,

2 MTA-DE Cell Biology and Signalling Research Group, Faculty of Medicine, University of Debrecen, Hungary

3 Department of Pharmaceutical Chemistry, University of Ljubljana, Slovenia, 4 Department of Immunology, Faculty of Medicine, University of Debrecen, Hungary

The human voltage-gated proton channel (hH_V1) plays an important role in immune system and cancer cells being involved in functions such as proliferation, migration, and oxidative burst. H_V1 does not have a conventional ion-conducting pore, the conduction occurs through the voltage-sensing domain. This difference may be the reason for the lack of selective hH_V1 inhibitors. Currently, 5-chloro-2-guanidinobenzimidazole (ClGBI) is the most widely used inhibitor of H_V1 but it has low selectivity for the channel. This could lead to misinterpretation of functional assays addressing the role of H_V1 with the use of ClGBI. Thus, our aim was to find potent and more selective inhibitors for hH_V1, which could be useful research tools and serve as lead molecules for the development of drug molecules targeting H_V1.

We used patch-clamp to test the affinity and selectivity of potential inhibitors of H_V1 on CHO and HEK cells expressing hH_V1 and other channels. Seven “hit” molecules were identified among the NZ family of compounds of which NZ-13 has the best selectivity profile.

The widely-used HV1 inhibitor ClGBI blocks various ion channels and therefore is not a selective HV1 blocker. This must be considered in functional tests investigating the role of HV1 in healthy and pathological conditions.

We have identified a new family of hHV1 inhibitors, which have comparable affinities for the channel to ClGBI.

Most NZ molecules have low selectivity for hHV1, but NZ-13, the one with the highest selectivity, may be better suited for functional tests than ClGBI as it inhibits T cell proliferation less.