Colorimetric and electrochemical phosphodiesterase inhibition assays for yessotoxin detection: development and comparison with LC-MS/MS

Emerging Optical Materials in Sensing and Discovery of Bioactive Compounds

Optical biosensors are used in numerous applications and analytical fields. Advances in these sensor platforms offer high sensitivity, selectivity, miniaturization, and real-time analysis, among many other advantages. Research into bioactive natural products serves both to protect against potentially dangerous toxic compounds and to promote pharmacological innovation in drug discovery, as these compounds have unique chemical compositions that may be characterized by greater safety and efficacy. However, conventional methods for detecting these biomolecules have drawbacks, as they are time-consuming and expensive. As an alternative, optical biosensors offer a faster, simpler, and less expensive means of detecting various biomolecules of clinical interest. In this review, an overview of recent developments in optical biosensors for the detection and monitoring of aquatic biotoxins to prevent public health risks is first provided. In addition, the advantages and applicability of these biosensors in the field of drug discovery, including high-throughput screening, are discussed. The contribution of the investigated technological advances in the timely and sensitive detection of biotoxins while deciphering the pathways to discover bioactive compounds with great health-promoting prospects is envisaged to meet the increasing demands of healthcare systems.

Translocation of PKC by yessotoxin in an in vitro model of Alzheimer's disease with improvement of tau and β-amyloid pathology

Yessotoxin is a marine phycotoxin that induces motor alterations in mice after intraperitoneal injection. In primary cortical neurons, yessotoxin treatment induced a caspase-independent cell death with an IC50 of 4.27 nM. This neurotoxicity was enhanced by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid and partially blocked by amiloride. Unlike previous studies, yessotoxin did not increase cyclic adenosine monophosphate levels or produce any change in phosphodiesterase 4 steady state expression in triple transgenic neurons. Since phosphodiesterases (PDEs) are engaged in learning and memory, we studied the in vitro effect of the toxin against Alzheimer's disease hallmarks and observed that pretreatment of cortical 3xTg-AD neurons with a low nanomolar concentration of yessotoxin showed a decrease expression of hyperphosphorylated tau isoforms and intracellular accumulation of amyloid-beta. These effects were accompanied with an increase in the level of the inactive isoform of the glycogen synthase kinase 3 and also by a translocation of protein kinase C from cytosol to membrane, pointing to its activation. In fact, inhibition of protein kinase C with GF109203X blocked the effect of yessotoxin over tau protein. The data presented here shows that 1 nM yessotoxin activates protein kinase C with beneficial effects over the main Alzheimer's disease hallmarks, tau and Aβ, in a cellular model obtained from 3xTg-AD fetuses.