Page URL:

Gene therapy in mice restores sense of smell

10 September 2012
Appeared in BioNews 672

Scientists have restored the sense of smell in mice using a gene therapy designed to repair the cilia - hair-like formations on nasal cells that are important in olfaction.

The study, published in Nature Medicine, was carried out on mice with a genetic disorder preventing their cilia from properly forming. Receptors that bind scent molecules are located on cilia in the upper passages of the nose, explaining why a lack of cilia results in a loss in the ability to smell.

The mutations and cellular mechanisms that contribute to such problems in humans - 'ciliopathies' - have been well studied, reports Nature News, but Dr Jeffrey Martens, pharmacologist and study leader at the University of Michigan, USA, explained: 'There's been very little work done in the area of therapeutics'.

The disruption in cilia formation in this experiment was caused by a mutant gene which codes for a protein known as intraflagellar transport 88 (IFT88). This gene defect is associated with poor feeding abilities and a short life span in mice and is fatal in humans.

The scientists were able to insert normal IFT88 genes into the mouse cells by injecting them with a virus containing the correct DNA sequence. The virus, normally responsible for the common cold, went on to insert the DNA into the cells of the mice, repairing the original defect.

After two weeks, the mice demonstrated a dramatic increase in bodyweight, signalling their feeding had improved, and tests showed that the neurons were firing correctly when exposed to the strong smell of banana oil.

'It is a proof of concept that has shown we can get that gene back into these cells, produce the right protein, produce cilia and function as expected', said Professor Philip Beales, a researcher at the Institute of Child Health, University College London who also contributed to the study.

Poorly formed cilia are associated with many disorders, including polycystic kidney disease, eye problems and rare inherited disorders such as Alström syndrome, Bardet-Biedl syndrome, primary ciliary dyskinesia and nephronopthisis. The researchers are hopeful that their work may eventually lead to treatments for patients affected by these diseases.

However, others are doubtful of any near-term applications. Gene therapy would only benefit selective cases caused by genetic defects. An inability to smell, known as 'anosmia', can also be caused by a range of other factors, from chronic sinus problems to head trauma.

Speaking to Nature News, Professor Joseph Gleeson, a neurogeneticist at the University of California, San Diego, added that olfactory neurons are replaced regularly, unlike other neuron systems, and so the benefits may not translate into the clinic. He also highlighted the potential risks of gene therapy, including viral vectors spreading to unintended cells and immune responses, and stressed that the side effects should be considered against the relative benefits of regaining a sense of smell.

Can't smell anything? This discovery may give you hope
EurekAlert! (press release) |  2 September 2012
Gene therapy rescues cilia defects and restores olfactory function in a mammalian ciliopathy model
Nature Medicine |  2 September 2012
Gene therapy restores sense of smell in mice
BBC News |  3 September 2012
Gene therapy restores sense of smell to mice
Nature News |  4 September 2012
People who've lost sense of smell offered fresh hope after gene therapy breakthrough
Mail Online |  3 September 2012
5 August 2013 - by Matthew Thomas 
Whether a smell strikes you as fragrant or fetid – or if you even notice it at all – may be influenced by your genes, according to a pair of studies...
17 June 2013 - by Rhys Baker 
A 'non-invasive' method for delivering gene therapy into the eye has been developed by US researchers...
30 July 2012 - by Dr Rosie Morley 
The European Medicines Agency has recommended European Union market approval for a gene therapy, Glybera, to treat patients with severe cases of a rare genetic condition called lipoprotein lipase deficiency...
2 July 2012 - by Dr Linda Wijlaars 
A gene that codes for nicotine antibodies has been successful in immunising mice against the drug's effects. But although the treatment appears to work in mice, any 'smoking vaccine' is still a long way off...
25 June 2012 - by Holly Rogers 
A single dose of an 'antisense' drug has been shown to slow, or even partially reverse, Huntington's disease in animal studies, according to a study published in Neuron....
8 May 2012 - by Helen Brooks 
HIV patients treated over a decade ago with genetically modified immune cells have suffered no serious side effects from the treatment. Although the cells may not have been successful in targeting and killing HIV-infected cells, the results are promising as they bolster the safety credentials of gene therapy for clinical use...
16 April 2012 - by Dr Kimberley Bryon-Dodd 
A woman with Parkinson's disease is reportedly able to write again for the first time in 15 years after receiving pioneering gene therapy at Addenbrooke's Hospital, Cambridge. Mrs Shelia Roy took part in an early stage clinical trial of ProSavin - a treatment developed by biopharmaceutical company, Oxford BioMedica....
to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions

Syndicate this story - click here to enquire about using this story.