Involvement of MicroRNA-155 in the development and progression of asthma

It is estimated that asthma causes a loos of 1.2 billion in productivity each year, affecting over a 5 million people in the UK. In the UK it causes an estimated 1,500 deaths and 74,000 emergency hospital admissions a year in the UK (It is the commonest reason for admission of children to hospital). According to the WHO, it is predicted that, without urgent action, asthma deaths will rise a 20% in the next 10 years in the whole planet. Despise of these facts, asthma has received little research investment, compared to other malignancies, which may be the underlying reason for this unmet clinical challenge.
In the proposed project, we intend to contribute to both clinical and basic science at the same time. We bring expertise in the one of the most novel basic fields in research (Dr Tilman Sanchez-Elsner) together with a deep understanding of the disease from the clinical and basic science point of view (Professor Donna E. Davies and Dr Peter Howarth). Our understanding is that asthma has to be studied employing relevant sources of material and this is why we intend to use human samples from asthmatics and non-asthmatics volunteers. This will be done observing the ethical recommendations already in place in our Hospital. The access to this kind of samples will help us unravel a novel and intricate molecular mechanism, under high basic science standards, which has consequences on a clinical problem with obvious social impact as asthma. This molecular mechanism, the role of small RNAs (microRNAs), hasn?t been studied in depth yet in the clinical field, due to its relatively recent discovery (Nobel Prize award in 2006). According to our preliminary data, microRNAs could be behind several symptoms suffered by asthmatics, as the asthmatic inflammation and the fibrotic airway remodelling. This is because microRNAs can act as master switches, controlling more than one process at the same time. If our initial results and our hypothesis are confirmed, we could unveil many unknown aspects that could help find out new therapies and be used to diagnose patients and monitor how they are responding to a given treatment. If successful, the consequences of this study could help improve the control of asthma in the future.

Asthma is a disorder that involves reversible obstruction of the conducting airways and it is characterized by both a Th2 mediated inflammation and by remodelling of the airways. A possible link between both processes could underlie in MicroRNAs (concretely microRNA-155), short-length (19-23 nt) and single-stranded oligonucleotides, which act as !Ymaster switches!
to regulate gene expression and cell phenotype. We hypothesise that miR-155 is reduced in asthma, and that it has a role as a master switch both in the inflammatory and airway remodelling components of the disease. Lower levels of miR-155 would allow pro-Th2 and pro-fibrotic genes to be expressed in higher amounts leading to the development of asthma.
Initially, we will determine miR-155 expression in different samples (see Objective 1). We will then determine the expression of key genes in asthma and control cells (qPCR, Western Blot, Flow Cytometry); analysis of gene expression after miR-155 induced over expression or down regulation (transfection with liposome reagents or lentiviral particles); mapping of binding regions in targeted genes (Luciferase reporter assays), and functional consequences employing in vitro wound healing models after either overexpression or knockdown of miR-155.
Our Objectives are:
1) Investigation of the expression of miR-155 in asthma: Expression of miR-155 in asthmatics (both constitutively and modulated by challenges) will be defined. Samples will be collected from donors (asthmatic and non-asthmatic, separating by sorting the different population of cells), and a set of experiments will be carried on volunteers, exposing them to allergic challenges.
2) Role of miR-155 in asthmatic airway remodelling: To investigate genes involved in fibrosis and remodelling in asthma and regulated by miR-155 either directly (IL13R??1, SMAD2, Angiotensin II Type 1 receptor) or indirectly (TGF-?O pathway, TGF-?O Receptor I and II, fibronectin and collagens). Functional wound healing assays.
3) Role of miR-155 in the asthmatic inflammation: To investigate genes involved in the immune imbalance in asthma and regulated by miR-155 either directly (IL13R??1, SOCS1, SOCS3, ITK) or indirectly (Th1/Th2 related genes).
The results from this study could establish a meaningful marker to monitor the status of an asthmatic patient (in clinical trials or routinely) as well as determine a potential therapy target. We will actively exploit and protect any IP at the University of Southampton through the Research and Innovation Services office. We will consider all IP within 6 months of generation and within 6 months of the end date of the grant at the latest.