Blue biotechnology on the Coast of Portugal: a prospection of neurological bioactive compounds from marine sponges

• Autor(a) principal: Gonçalves, Afonso Miguel dos Santos
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/164461
• topic: Sponges; Neuronal Bioactivity; Analgesic Potential; Electrophysiology; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Marine environments are vastly unexplored territories, being considered an untapped resource of chemical and biological molecules. Chances of new opportunities are emerging and likewise, the dis- covery of new potential pharmaceuticals. These bioactive compounds are present in a variety of inver- tebrates, such as the sponges (Porifera) studied in this project, found on the Coast of Sagres, south of Portugal. The extracts and fractions obtained from this organism were submitted to neuronal bioactivity evaluations by determining their possible effects on both potassium (K+) and sodium (Na+) currents of small diameter dorsal root ganglion neurons (sdDRG), dissected from naïve rats. The most active sam- ple in assessed resorting to electrophysiology studies, was elected to undergo bio guided fractionation process, to reach a purified fraction (99% purity) of the most prominent peak (S4U1). Under the presence of S4U1, whole-cell voltage-clamp were conducted to screen S4U1 against a platform of voltage-gated K+ and Na+ channels present at the surface of a well-established pain sensing cell model: sdDRG neurons (ex vivo testing). Ex vivo experiments recordings in rat sdDRG neurons showed decreased mean current density values in the presence of S4U1, mostly observed in the slow component of K+ currents (IK), suggesting a specific effect over IK, and in peak Na+ current. These results might be chiefly supported by a facilitation of the inactivation of K+ and Na+ currents, observed in the hyperpolarizing shift of both steady state inactivation curves, and in the increasing rate of the decaying phase of K+ currents. Thus, by ensuring the absence of S4U1 toxicity in human and animal cell lines (MTS), the bio- technological value of S4U1 was further analyzed through a study of its potential analgesic effect in animal (chronic) pain models (Chronic Constriction Injury- CCI; in vivo testing). Through the intrave- nous administration of S4U1 (in vivo testing) the reduction of pain was effectively observed, since, following an evaluation method in animal models, %MPE, there was an increase in the force applied by the von Frey monofilaments (vFF) in the ipsilateral side, in each period of time. The results showed a neuronal bioactive effect of S4U1 on pain sensing model cell (sdDRG), which was translated into a potential analgesic value verified in chronic pain models. Despite, the need to increase the experimental sample size, S4U1 is here presented as a possible new therapeutic drug for chronic pain treatment.