Molekuláris Orvostudomány Doktori Iskola

Állandó link (URI) ehhez a gyűjteményhez

https://hdl.handle.net/2437/2315

Általános Orvostudományi Kar

Molekuláris Orvostudomány Doktori Iskola
(vezető: Dr. Csernoch László)

Orvostudományi doktori tanács

D42

tudományág:
-elméleti orvostudományok

Doktori programok:

  • Jelátviteli folyamatok sejt- és molekuláris biológiája
    (programvezető: Dr. Virág László)
  • Membránbiofizikai kérdések és vizsgálómódszerek
    (programvezető: Dr. Szöllősi János)
  • Élettan és neurobiológia
    (programvezető: Dr. Csernoch László)

Böngészés

Molekuláris Orvostudomány Doktori Iskola Szerző szerinti böngészés "Általános Orvostudományi Kar::Biofizikai és Sejtbiológiai Intézet::Biofizikai Tanszék"

Megjelenítve 1 - 2 (Összesen 2)
  • Nincs kép
    TételSzabadon hozzáférhető
    Characterization of scorpion peptide toxins that target voltage-gated potassium channels
    (2025) Shakeel, Kashmala; Panyi, György; Molekuláris orvostudomány doktori iskola; Általános Orvostudományi Kar::Biofizikai és Sejtbiológiai Intézet::Biofizikai Tanszék
    The Kv1.2 ion channels play a vital role in the regulation of membrane potential and excitability of neurons and are widely distributed in CNS. In 2016, Kv1.2 related GOF mutations and their role in the progression of epileptic encephalopathy (EE) were described. It has been experimentally verified that the inhibition of the Kv1.2 current can be a potential approach to cure EE. The aim of this research was to identify and characterize a potent and selective inhibitor of Kv1.2 ion channel from the venom of scorpions. With the help of our collaborators, we isolated seven new peptides (CboK1-CboK7, 32-39 amino acid residues) from venom of C. bonito, two peptides from the venom of C. villegasi (Cvill6 and Cvill7, 38 and 39 amino acid residues) and a synthetic peptide, sCm39, which was identified from the venom of a known scorpion C. margaritatus. Electrophysiological characterization of seven peptides showed that among all except CboK1 all six peptides inhibit Kv1.2 with high affinity (Kd values between 24-763 pM) and have reasonable selectivity over Kv1.3 (Kd values between 20.4-171 nM). Of these seven, CboK7 emerged as a high-affinity and selective blocker of Kv1.2, having 850-fold and 6000-fold selectivity over Kv1.3 and Kv1.1. Pharmacological analysis of Cvill peptides shows that Cvill6 has moderate affinity for Kv1.2 (Kd = 3.9 nM) whereas Cvill7 possesses high Kv1.2 affinity (Kd = 16 pM). Cvill6 has 215-fold and 59-fold selectivity over Kv1.3 and KCa3.1, respectively. In contrast Cvill7 has high selectivity for Kv1.2 over Kv1.3 and KCa3.1 (450-fold and 33000-fold, respectively). Binding kinetics analysis suggests that Cvill6 and Cvill7 follow the binding pattern of classical pore blockers. sCm39 inhibited Kv1.2 currents with Kd value of 65 nM and does not show any effect on Kv1.1 and Kv1.3 at 1 at 1 µM. The investigation for the mechanism of block and binding kinetics revealed that Cm39 binds to the pore of the Kv1.2 ion channel thus it is not a gating-modifier. In summary, this dissertation presents the electrophysiological characterization of ten peptide toxins, among which two CboK7 and Cvill7 emerged as potent, high-affinity blockers of the Kv1.2 ion channel. These findings lay the groundwork for identifying key amino acid residues critical for high-affinity Kv1.2 blockade. Moreover, they provide a valuable foundation for the potential therapeutic application of Kv1.2-targeting peptides in the treatment of epileptic encephalopathy (EE) and other related neurological disorders.
  • Nincs kép
    TételSzabadon hozzáférhető
    Role of ions channels in CAR-T cells
    (2025) Medyouni, Ghofrane; Hajdu Béla, Péter; Molekuláris orvostudomány doktori iskola; Általános Orvostudományi Kar::Biofizikai és Sejtbiológiai Intézet; Általános Orvostudományi Kar::Biofizikai és Sejtbiológiai Intézet::Biofizikai Tanszék
    T cell ion channels (Kv1.3, KCa3.1 and CRAC) regulate the activation and effector functions via modulating the Ca2+-dependent pathway. Chimeric antigen receptor (CAR T cell therapy) showed a remarkable success in anti-tumor therapy, especially in the treatment of chemotherapy-resistant liquid cancers. Nevertheless, the mechanisms regulating CAR-T cell function as well as the side effects remain an area of active research.In our research study, we assessed the expression and role of ion channels in CAR T cells using a Jurkat-cell model and in primary T cells. Our results from molecular, electrophysiological and functional assays highlight that the KCa3.1 conductance in HER2-specific CAR T cells was higher compared to the non-transduced (NT, control) cells, which was more prominent in the CD8+ population (CD4+ cell also showed elevation). The Kv1.3 expression level was the same for all cell types (CD4+, CD8+, CAR, and NT). Single-cell Ca2+ imaging revealed that thapsigargin-induced SOCE via CRAC is suppressed in CD8+ CAR T cells, unlike for CD4+ and CD8+ NT cells. The use of specific antagonists (Kv1.3: Vm24; KCa3.1: TRAM-34): showed that the target cell elimination capacity of the CD8+ CAR T cells was improved either by blocking KCa3.1 or Kv1.3.By means of our Jurkat-CAR cell line we could show that Kv1.3 channels is colocalized with CAR and redistributes into the synapse between a CAR and a target cell. The biophysical properties of Kv1.3 channel are not vastly affected by the introduction of CAR in the cells when Kv1.3 is the only expressed channel. The blockage of Kv1.3 channel lateral movement to the synapse affects the killing potential of CAR-T cells, likely through disruption of the Ca2+-response upon IS formation. Overall, these data suggest that the manipulation of the Kv1.3 channel may contribute to the improvement of CAR-T immunotherapy and provide new insights for future clinical strategies.