Hohoe (V/R), Feb. 6, - An
ingredient commonly found in toothpaste could be employed as an anti-malarial
drug against strains of the malaria parasite that have grown resistant to one
of the currently-used drugs.
This discovery, led by
researchers at the University of Cambridge, was aided by Eve, an
artificially-intelligent (AI) ‘robot scientist’.
When a mosquito infected with
malaria parasites bites someone, it transfers the parasites into their
bloodstream via its saliva. These parasites work their way into the liver,
where they mature and reproduce.
After a few days, the parasites
leave the liver and hijack red blood cells, where they continue to multiply,
spreading around the body and causing symptoms, including potentially
life-threatening complications.
Malaria kills over half a million
people each year, predominantly in Africa and south-east Asia. While a number
of medicines are used to treat the disease, malaria parasites are growing
increasingly resistant to these drugs, raising the spectre of untreatable
malaria in the future.
Now, in a study published in the
journal Scientific Reports, available to the Ghana News Agency, a team of
researchers employed the Robot Scientist ‘Eve’ in a high-throughput screen and
discovered that triclosan, an ingredient found in many toothpastes, may help
the fight against drug-resistance.
When used in toothpaste,
triclosan prevents the build-up of plaque bacteria by inhibiting the action of
an enzyme known as enoyl reductase (ENR), which is involved in the production
of fatty acids.
Scientists have known for some
time that triclosan also inhibits the growth in culture of the malaria parasite
Plasmodium during the blood-stage, and assumed that this was because it was
targeting ENR, which is found in the liver. However, subsequent work showed
that improving triclosan’s ability to target ENR had no effect on parasite
growth in the blood.
It said working with ‘Eve’, the
research team discovered that in fact, triclosan affects parasite growth by
specifically inhibiting an entirely different enzyme of the malaria parasite,
called DHFR.
DHFR is the target of a
well-established antimalarial drug, pyrimethamine; however, resistance to the
drug among malaria parasites is common, particularly in Africa.
The Cambridge team showed that
triclosan was able to target and act on this enzyme even in
pyrimethamine-resistant parasites.
“Drug-resistant malaria is
becoming an increasingly significant threat in Africa and south-east Asia, and
our medicine chest of effective treatments is slowly depleting,” says Professor
Steve Oliver from the Cambridge Systems Biology Centre and the Department of
Biochemistry at the University of Cambridge.
“The search for new medicines is
becoming increasingly urgent.”
Because triclosan inhibits both
ENR and DHFR, the researchers say it may be possible to target the parasite at
both the liver stage and the later blood stage.
Lead author Dr Elizabeth
Bilsland, now an assistant professor at the University of Campinas, Brazil,
adds: “The discovery by our robot ‘colleague’ Eve that triclosan is effective
against malaria targets offers hope that we may be able to use it to develop a
new drug. We know it is a safe compound, and its ability to target two points
in the malaria parasite’s lifecycle means the parasite will find it difficult
to evolve resistance.”
Robot scientist Eve was developed
by a team of scientists at the Universities of Manchester, Aberystwyth, and
Cambridge to automate – and hence speed up – the drug discovery process by
automatically developing and testing hypotheses to explain observations, run
experiments using laboratory robotics, interpret the results to amend their
hypotheses, and then repeat the cycle, automating high-throughput
hypothesis-led research.
Professor Ross King from the
Manchester Institute of Biotechnology at the University of Manchester, who led
the development of Eve, says: “Artificial intelligence and machine learning
enables us to create automated scientists that do not just take a ‘brute force’
approach, but rather take an intelligent approach to science. This could
greatly speed up the drug discovery progress and potentially reap huge rewards.”
The research was supported by the
Biotechnology & Biological Sciences Research Council, the European
Commission, the Gates Foundation and FAPESP (São Paulo Research Foundation).
GNA
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