Resumen de Desenvolupament i caracterització de nanoformulaciones proteiques com alternatives terapèutiques per reduir l'ús d'antibiòtics
The emergence of bacterial drug resistance to conventional antibiotics is a global alarming situation. This worrying scenario has forced the implementation of measures such us improved hygiene practices or antibiotic stewardship to reduce antimicrobial usage in all areas in which these therapeutics are commonly used, including human and animal medicine and food-producing animal industry. All these measures are intended to diminish the appearance and spread of drug resistance among bacteria, but when it comes to combat against drug or multidrug resistant bacteria, alternatives to traditional antibiotics are urgently needed. In this context, different strategies have been proposed as promising alternatives to antibiotics, including the use of cytokines and antimicrobial peptides (AMPs). Cytokines are small intercellular regulatory proteins that play a central role in initiating, maintaining, and regulating the innate immune response. Specifically, IFN-γ has a pivotal role in promoting protective immunity against infections. On the other hand, AMPs such as GWH1, are generally small cationic peptides with an amphipathic nature that have a broad-spectrum antibacterial, antifungal and antiviral activities, the ability to modulate the host immune response and a reduced possibility of inducing bacterial drug resistance. Despite their potential as anti-infective agents, cytokines and AMPs are subjected to several disadvantages that must be addressed prior to their possible biomedical application. In particular, low stability is a common drawback associated to these type of protein compounds. In this sense, different technologies and strategies have been applied in order to overpass this limitation and improve the efficiency of these drugs after administration. Most of these strategies consist on the vehicularization of these proteins or peptides into superior complexes, providing a protective environment and allowing the possibility of deliver them to the target site. The formation of these superior structures may be modulated by a direct rational design over the recombinant protein gene, such as que incorporation of certain peptides into the protein structure to generate building blocks for spontaneous self-assembling (soluble nanoparticles), or to obtain prone-to-aggregate proteins (inclusion bodies -IBs-). Although seemingly different, these small-scale complexes all originate from fundamental protein interactions and are driven by similar thermodynamic and kinetic factors finally leading to the formation of different proteins formats; superior structural arrangements that involve through directed or not directed interactions, the convergence of isolated protein forms.
In this thesis, the nanoformulation of these molecules (cytokines and AMPs) into different protein formats including IBs and soluble self-assembling nanoparticles have been characterized and evaluated with the aim to develop therapeutic alternatives to antibiotics. In addition, some light has been shed on the forces that govern the aggregation process and how it can be modulated to promote the formation of IBs.
