Brazilian researchers studying local poisonous fish have confirmed the path to developing drugs to treat chronic inflammatory diseases such as multiple sclerosis and asthma.
The venomous toad Thalassophryne nattereri contains a peptide (TnP) that has anti-inflammatory and anti-allergic potential. Currently, confirmation of this potential has occurred with the zebrafish Danio rerio, a popular aquarium species native to South Asia that shares 70% of its genome with humans and is widely used as a model for in vivo testing in drug development.
The researchers tested TnP in D. rerio to measure its toxicity. A little over a year of their research has shown that the peptide is safe. This did not cause cardiac dysfunction and neurological problems in the toxicity tests they conducted.
The study was conducted at the Special Laboratory of Applied Toxicology of the Butantan Institute in São Paulo (Brazil) by researchers associated with the Center for Toxin Research, Immune Response and Cell Signaling (CeTICS), one of the Research, Innovation and Dissemination Centers (RIDC). funded by the Sao Paulo Research Foundation - 1; FAPESP.
In addition to confirming the safety of the peptide when used as an anti-inflammatory agent, the results reinforce the value of D. rerio as an alternative animal model for drug development that saves time and money.
Preclinical trials are important in order to prove the efficacy (therapeutic activity) of molecules in vivo and to evaluate adverse effects and safety. When drugs are discovered, 98% of compounds tested on animals refuse to conduct clinical trials.
In an article published in Toxicology reports, researchers say that peptides make up about 2% of the global drug market, but even so the market share is about $ 20 billion.
“The results emphasize the broad therapeutic TnP index at non-lethal and safe doses of 1 nm [nanometer] up to 10 µm [micrometer]without causing neurotoxicity or cardiotoxic effect. Low frequency of violations [caused] TnP has been linked to the high safety of the molecule and the ability of the developing embryo to process and eliminate it. TnP crossed the blood-brain barrier without disrupting the normal architecture of the forebrain, midbrain and hindbrain [the three main developmental divisions of the brain], “the authors write.
The study was the result of a master’s study by Juan Batista-Filho, conducted by Monica Lopez Ferreira and Carla Lima da Silva. It used the Zebrafish platform, launched in 2015 by CeTICS (more on the website: agencia.FAPESP.br/22156/).
The Zebrafish platform is available to scientists for research, offers courses in zebrafish management and biology, and conducts scientific dissemination. Currently, more than 160 researchers in 100 private and public institutions collaborate through the Zebrafish Network, also created by CeTiCS.
"Science is dying out without investment, and FAPESP’s commitment to this platform is now bearing fruit. It conducts cutting-edge research as well as pre-clinical trials that are important to both academia and industry.”
Monica Lopez Ferreira, head
The zebrafish has been used for decades in trials conducted in other countries, she said, adding that Brazil is bridging the gap and that the animal’s fast life cycle is speeding up the research process.
Control freshwater species easily, multiplying rapidly, developing from egg to larva in 48-72 hours and reaching adulthood only at the age of three months. The zebrafish embryos are transparent, and, for example, the effect of the compound on animal organs can be easily observed.
Ferreira and his colleagues discovered TnP (T. nattereri peptide) in 2007. Meanwhile, Lima conducted standardized laboratory tests to assess multiple sclerosis in rodents. The two researchers decided to conduct a joint test of the effectiveness of TnP in the treatment of the disease, concluding that it has anti-inflammatory and immunomodulatory functions.
The TnP family encompasses synthetic peptides that in their primary structure contain a sequence of 13 L-amino acids. Synthetic products derived from TnP have been patented in at least nine countries, including the US, India and Japan, as well as the EU. In Brazil, the patent application was filed in partnership with the pharmaceutical company Cristália.
Studies conducted by a group of mice between 2013 and 2015 have already demonstrated that TnP can treat multiple sclerosis by delaying the onset of severe symptoms and improving the clinical signs of the disease.
Multiple sclerosis is a chronic autoimmune inflammatory disorder of the central nervous system in which the immune system attacks the myelin sheath, which protects the nerve fibers of the brain, spinal and optic nerves, disrupting communication with the rest of the body. This can cause muscle weakness, vision loss, pain and incoordination. According to the Brazilian Association for Multiple Sclerosis (ABEM), it affects about 2.5 million people worldwide, including about 35,000 in Brazil.
In an article published in Toxicology reports, researchers say drug-induced cardiotoxicity is a major reason for drug withdrawal from the market. “For example, between 1994 and 2006, 45% of discontinued drugs had adverse effects such as cardiac ischemia and arrhythmogenesis. In this series, zebrafish became the model organism for cardiovascular studies, gene function studies, and simulations of various human side effects. chemotherapeutic drugs or, in particular, for the selection of candidates for drugs, “they said.
For Batista-Phil, the study provides more evidence of the value of the zebrafish model in preclinical studies. “This does not replace mice, but avoids future costs for molecules that may be unpromising or prove too toxic in previous stages,” he said when asked about reservations about using zebrafish in trials compared to rodents.
Promoting investment in science and research in Brazil, Batista-Fillo said he was very excited to achieve the publication of his master’s thesis in a scientific journal. “I’m thrilled,” he said. “Publishing is an important step for any scientist. You are focused on what research can do, but publishing is a recognition of the hard work of the team.”