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Gene silencing approach to fight chikungunya

17 October 2012

Dr Chu (middle) holding the X-ray film of chikungunya virus protein expression profile. With him are Ms Lam (right), the leading researcher and Mr Chen Huixin (left), the laboratory executive for this study.

Photo: Lianhe Zaobao, Singapore Press Holdings Ltd

NUS scientists have developed a gene-based technology to fight chikungunya, a mosquito-borne disease that has no cure or vaccine.

Chikungunya has dengue-like symptoms including fever, chills, rashes and muscular and joint aches. Some 2.5 billion people worldwide, especially in Southeast Asia and India, are at risk from the disease. In Singapore, more than a thousand were afflicted from 2008 to 2010.

Even though most patients recover within a week, painful joints in serious cases can persist for months or even years. Infants and people with low immunity are more vulnerable to the disease which can become fatal. Existing drugs only alleviate the symptoms and aches, while possible vaccines are still in the pre-clinical phase.

The Singapore discovery uses a gene silencing approach, named "small-hairpin RNA" by the NUS Yong Loo Lin School of Medicine's four researchers, to stop the chikungunya virus from replicating and subsequently kill it. The small-hairpin RNA also inhibits different strains of the virus from various geographical locations. Believed to be the first such antiviral strategy against chikungunya virus, the findings were published recently in international online journal PLOS One.

When the small piece of interfering RNA is introduced into a cell before being infected by the chikungunya virus, the bug loses its ability to reproduce or is killed. Postgraduate student Ms Shirley Lam who led the project, said that the approach destroyed the chikungunya virus tested on human cells and animals within three days, as well as protected cells for up to 15 days. This could pave the way to blocking the virus and developing an antiviral treatment.

For her innovative work, Ms Lam clinched the Singapore Young Scientist Award at the Singapore Health and Biomedical Congress 2012 in September.

Principal investigator Assistant Professor Justin Chu explained that the gene silencing method "turns off" and suppresses the viral gene from expressing itself. Besides producing a faster preventive effect, it also promises a cure, making it more attractive than a vaccine. This technique is generating considerable interest in the medical field, especially in cancer therapy.

The researchers plan to begin clinical trials once they receive funding for the study.