iNKT cells as drivers for preterm labour

The purpose of this work is to develop treatments to prevent preterm birth. Preterm birth is a big health problem. Globally, over 1 million children die each year from the complications of preterm birth. In the UK around 55,000 babies (around 7.8% of all UK births) are born preterm. Despite much effort, these rates are rising. Although survival rates are improving, with 77% of UK babies born at 26 weeks gestation now leaving hospital, survivors are at increased risk of short term morbidity and long term disability. Long term disability includes respiratory problems, motor and sensory impairment, learning difficulties, and social and behavioral difficulties and is driven not only by the consequences of prematurity, but by the intrauterine inflammation which precedes prematurity. Together the complications of preterm birth result in a £2.946 billion estimated annual costs of preterm birth to the public purse in England and Wales (2006 prices).

Unfortunately, there are hardly any treatments in development for preterm birth. Even if we use all the treatments we currently have for all women at risk, preterm birth rates will only fall by 0.2% in the UK i.e., from 7.8% to 7.6%. We and others have suggested that this lack of good treatments, and the lack of treatments in development is because we don't properly understand what causes women to go into preterm labour, nor do we understand what triggers labour at term.

We and others have shown that "inflammation" is key to the start of labour, both at term and preterm. We have tried several strategies to treat inflammation and hence prevent preterm labour, but none has yet been effective. We think this is because we are trying to stop inflammation well after it has started. We are now going to look at some immune cells which are involved in the start of the inflammatory process and which have been shown to be important in stimulating preterm labour in a mouse model. These cells (invariant [i] NKT cells) are important because they link two halves of the immune system, and because they can respond rapidly to "danger" signals, including those present in pregnant women.

In this study we are going to look at these cells in the place that we think that labour starts - the lining of the womb which separates mother from baby. We will see what happens in the lining of the womb in labour, and then look at how the iNKT cells change in the lining of the womb in labour. We will see if we can start labour in a mouse model by stimulating these iNKT cells, and then see if drugs which prevent iNKT activation can prevent inflammation induced preterm labour. Next, we will look to see if these iNKT cells are activated early in the process of labour - we think they will be. Lastly, we will see how progesterone, which is currently used to treat preterm labour in some women, might affect iNKT cells.

We believe our work will generate new understanding of how labour starts, and so ultimately develop treatments to prevent preterm labour. Such treatments could make major inroads into preventing the deaths of up to 1 million children per year.

The purpose of this work is to characterise invariant (i) NKT activation at the maternofetal interface during labour in women, and test the efficacy of iNKT directed therapies.
1. To determine the key changes in the transcriptome of the human decidua at the onset of labour, we will obtain decidua from the Edinburgh Reproductive Tissue Bank from women in labour at term or preterm and undertake microarray analysis, followed by a combination of statistical and network analyses using Bioconductor and Biolayout Express3D respectively.
2. To determine evidence of iNKT cell activation at the maternofetal interface during human term and preterm labour, we will use flow cytometry to quantify and determine activation status of the cell types involved, including iNKT cells and their downstream effector cells. Additional analysis will be performed using a match-configured LSRFortessa, and FACSDiVa or FlowJo.
3. To determine if iNKT activation is sufficient for the onset of preterm labour in a mouse model, we will use our mouse model of preterm birth. On day 17 of gestation CD-1mice will receive an intrauterine injection of the iNKT cells activator alpha GalCer or PBS. We will measure time to delivery and fetal viability at birth.
4. To determine the timing of activation if iNKT and downstream effector cells in infection induced preterm labour in the mouse, we will use the model described in (3) followed by FACS of decidua from mice harvested 1 or 6 hrs after injection.
5. To determine whether iNKT inhibitor drugs prevent preterm labour, we will use di-palmiotoyl-phosphatidylethanolamine polyethylene glycol (DPPE-PEG), a CD1 binding lipid antagonist to prevent preterm delivery in our mouse model of LPS induced preterm birth and record outcomes as in (3).
6. To determine whether iNKT activation is amplified by progesterone withdrawal, we will incubate FACS sorted decidual iNKT cells with increasing concentrations of progesterone, and measure functional read outs.

Who will benefit from this research?
We anticipate our work will develop novel therapeutic strategies for preterm birth prevention. Thus this research will ultimately benefit the babies who would otherwise be born preterm each year. Globally, 15 million babies are born preterm annually with over 1 million children dying each year from the complications of preterm birth. In the UK 55,000 babies are born preterm. Although survival rates are improving (with 77% of UK babies born at 26 weeks gestation now leaving hospital), survivors are at increased risk of short term morbidity and long term disability, including respiratory problems, motor and sensory impairment, learning difficulties, and social and behavioral difficulties. The adverse consequences of preterm birth have a major impact, not only on the babies themselves and their families, but on the health and wealth of the nation. For example in the UK alone, the complications of preterm birth result in a £2.946 billion estimated annual costs of preterm birth to the public purse in England and Wales (2006 prices).

Other beneficiaries will include those in the research fields of preterm birth and the immunology of pregnancy (including pharma), as we anticipate our work will provide valuable new information in these fields. Additionally and specifically we will publish annotated microarrays and FACS data from (i) decidua from women in term and preterm labour with gestation matched controls and (ii) iNKT cells harvested from maternal decidua. Both will be a resource and a benefit for the scientific community. To our knowledge, there has been no previous publication of microarrays identifying changes in the transcriptome of the decidua. Thus the novelty of this approach will generate a major new resource of the analysis of this tissue for ourselves and for other groups. Benefits to pharma will be facilitated by the University of Edinburgh's strong commitment to drug translation and commercialization, and their investments in this area.

Lastly, this project will further develop the research team (including the applicants and the postdoctoral fellow), and cement this novel collaboration, building capacity for future work in this important area of unmet clinical need.

How will they benefit?
The above named beneficiaries will benefit from the novel information produced, from the data resources generated, and by training, experience and capacity development.