Exploring molecular mechanisms of key targets in metabolic and infectious diseases
- Autores: Elnaz Aledavood
- Directores de la Tesis: Francisco Javier Luque Garriga (dir. tes.), Carolina Estarellas Martín (codir. tes.)
- Lectura: En la Universitat de Barcelona ( España ) en 2021
- Idioma: inglés
- Tribunal Calificador de la Tesis: Pablo Chacon Montes (presid.), Salomé Llabrés Prat (secret.), Alberto Pérez Antoñanzas (voc.)
- Programa de doctorado: Programa de Doctorado en Biotecnología por la Universidad de Barcelona
- Materias:
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- Resumen
This doctoral thesis is focused on disclosing molecular factors that regulate the functional mechanism of key targets in i) metabolic disorders, such as diabetes and obesity, and ii) tuberculosis (TB). These diseases have a high impact on the public health, and TB is one of the diseases that cause highest mortality rates based on the World Health Organization reports. Accordingly, gaining insight on functionally relevant protein structures with key roles in these diseases and understanding their regulatory mechanisms can pave a way to identify novel therapeutic targets.
Regarding the metabolic disorders, I have specifically studied the direct activation mechanism of adenosinemonophosphate activated protein kinase (AMPK) by different activators, such as A-769662, SC4 and PF-739, since AMPK plays an important role in cellular energy homeostasis and it is directly related to diabetes type 2 and obesity. These studies were carried out to explore the molecular basis of the selective isoform activation of AMPK, especially focusing on the role played by the two different isoforms of β subunit. The first part of this research was focused on the direct activation by A-769662 compound in α2β1 isoform, and the second part addressed the important issue of isoform selectivity, it being dedicated to examine the structural and dynamical properties of β1- and β2-containing AMPK complexes formed with A-769662, SC4 and PF-739.
The results revealed the mechanical sensitivity of the α2β1 complex, in contrast with a larger resilience of the α2β2 species. Moreover, binding of activators to α2β1 promotes the pre-organization of the ATP-binding site, favoring the adoption of activated states of the enzyme.
In another part of the research related to AMPK, in collaboration with Prof. Ana Castro from Institute of Medicinal Chemistry and Prof. María S. Fernández-Alonso from Complutense University of Madrid, I studied a novel indolic compound synthesized and experimentally analysed by their group as modulator of endothelial AMPK that acts as a mixed-type inhibitor. It means that this modulator, IND6, may bind the ATP-binding site leading to competitive inhibition of the enzyme but also suggest that IND6 may regulate the AMPK activity through binding to an additional pocket.
Regarding TB, I have studied the truncated hemoglobin N (trHbN) of Mycobacterium tuberculosis (Mtb).
These studies aimed to disclose innovative therapeutic approaches by identifying the molecular basis of the nitrosative stress resistance of Mtb. Our hypothesis was that a decrease in the nitric oxide (NO) resistance should affect the survival of the bacillus, increasing the efficacy of current therapeutic treatments. Nitric oxide detoxification (NOD) is carried out by trHbN, which converts NO into the harmless nitrate anion, becoming essential for the defense mechanism of Mtb. However, two points prevent the use of this system as therapeutic target. On the one side, trHbN is not druggable and there is the risk that a drug targeting trHbN may also affect other hemoglobins. On the other side, the reductase protein that helps trHbN to restore the ferrous state required to initiate the NOD is still unknown. Our studies have led to the identification of three reductase candidates for NOD activity. We have built the 3D models for the three candidates and performed the proteinprotein docking in order to obtain a reductase-trHbN complex. The important role played by one of these candidates, ndh, has been highlighted in several experimental studies. This led us to focus our attention in the trHbN-ndh complex and establish the steps that could help to advance in the definition of new therapeutic strategies for TB.
