Distinguishing between beneficial and detrimental effects of FoxO in Drosophila ageing: interactions between FoxO and ETS transcription factors.

The proportion of aged individuals is increasing in our society. For many, ageing means deteriorating health and wellbeing, loss of physical and mental abilities and increased susceptibility to numerous diseases. We are thus exposed to ever-increasing human and socioeconomic costs of ageing that need to be urgently addressed. For centuries we have understood ageing as an immutable fact of life. It came as a big surprise when we discovered that certain interventions can actually improve health in old age. Scientific effort is now invested into understanding how these interventions act and harnessing that knowledge to improve human health and wellbeing into old age.
Down-regulation of the signals that indicate the presence of nutrients, such as the well-known hormone, insulin, improve life-long health in organisms as different as worms, fruit flies and mice. There is a growing awareness that similar interventions may work in humans. However, down-regulation of these pivotal nutrient sensing mechanisms often has major detrimental effects precluding them from human use. For example, inability to produce or respond to insulin results in diabetes. We now need to understand how to capture the benefits of these interventions without causing harm.
Numerous interventions that extend healthy lifespan act by changing how the genetic information, carried in the organism's DNA, is used. They often specifically alter the first step in the expression of genetic information where the DNA code is transcribed into an RNA molecule. The regulation of transcription is performed by transcription factors and one such factor, called FoxO, has the ability to robustly improve life-long health and well being in all organisms examined. Indeed, certain variants of the gene encoding FoxO are also present in exceptionally long-lived humans, contributing to their longevity. However, similar to other anti-ageing interventions, FoxO activation can be detrimental. Hence, FoxO provides a good model to establish the molecular events that differentiate the two opposing outcomes.
I have recently discovered that the detrimental effects of FoxO are dependent on two other transcription factors called Pnt and Aop in the fruit fly. FoxO activated alone is beneficial but becomes detrimental if Pnt is activated as the same time. Pnt and Aop are engaged in a tug of war and Aop fosters beneficial effects of FoxO by counter-acting Pnt. Hence, health in old age is not solely determined by FoxO activity but is a matter negotiated between FoxO and Pnt/Aop. Understanding the intricacies of FoxO and Pnt/Aop exchange will define the molecular events that distinguish the good from the bad outcomes of FoxO activation.
I propose to use genetic and biochemical approaches to query how Pnt swings the effects of FoxO activation from good to bad. I will firstly examine the physical and functional interactions between FoxO and Pnt/Aop on the parts of DNA from which transcription is regulated, both in a test tube and in an intact cell. Secondly, I will determine how Pnt alters the pattern of gene regulation by FoxO in the relevant organs of the adult fruit fly. This will triage the genes that underlie the beneficial from those associated with the detrimental effects of FoxO activation. Pnt and Aop are members of a gene family - a set of genes that are related and likely perform similar functions. I will examine whether all members of this family show similar interactions with FoxO in a panel of fly organs, to determine whether the findings are more broadly applicable.
The study I am proposing is multifaceted, and the different aspect will converge to give us a clear understanding of the events, at a molecular scale, that differentiate the beneficial effects of FoxO activation from the potential detrimental outcomes. This knowledge will be important in devising strategies that can be used to improve human health and well being in old age, without unwanted, detrimental consequences.

Ageing is of growing medical, social and economic importance. Recent work in biogerontology has revealed mechanisms that could be used to improve human health and wellbeing in old age. However, these interventions also have a demonstrated potential to be detrimental. It is now imperative to understand how to harness the beneficial effects without the associated risks.
Key, evolutionarily conserved determinants of animal lifespan are the transcription factors (TFs) of the Forkhead Box O (FoxO) family. Variation in FoxO3A locus is robustly correlated with human longevity, and activation of FoxO members counteracts ageing in animal models.
The physiological effects of FoxO activation are context dependent, with both beneficial and detrimental outcomes observed. I have recently shown that the balance between the opposing effects of FoxO is dictated by its interaction with two evolutionarily conserved TFs of the E-twenty six (ETS) family in Drosophila. This interaction now provides an avenue to elucidate mechanisms differentiating the beneficial from detrimental effects of FoxO.
I propose to study this interaction at several levels. Guided by my recent data, I will examine in detail the physical and functional interactions between the TFs on gene-regulatory regions, in vitro and in vivo. In an in vivo, lifespan-relevant system, I will determine how the tissue-specific, genome-wide response to FoxO is altered by the two ETS TFs, simultaneously triaging the anti-ageing processes regulated by FoxO. Lastly, I will extend the observations to different ETS factors and different tissues and organs of the fruit fly.
As well as improving our knowledge of how transcriptional regulation underlies complex adult traits, the study will generate an integrated picture of how FoxO and ETS factors together determine animal's health and well being throughout life. This will allow us to harness the beneficial effects of FoxO activation while avoiding detrimental outcomes.

Potential beneficiaries of this research, in short and long-term, include:

1) Public care and healthcare services.
A substantial and ever-increasing amount of care efforts are targeted at older people. In the long-term, this basic research has the potential to result in treatments that reduce the occurrence of ageing-related health and fitness issues and hence will reduce the overall cost of care, including healthcare, in today's society, increasing effectiveness of a public service. There is a possibility that an anti-ageing intervention or drug may allow for increased health and wellbeing of the aged and prevent multiple, detrimental manifestations of ageing, hence further decreasing treatment cost. New treatments/interventions increasing the health and wellbeing at later ages, which may ultimately result from this research, will also improve the quality of the care system.

2) Older people.
Older people represent an ever-increasing portion of our society and often face immense personal costs due to ageing-related loss of function, decreased overall health and wellbeing, and increased occurrence of ageing-related conditions. The final aim of this research is to provide a basis for development of treatment for age-related conditions. In the long-term, this will result in tangible benefits in terms of increased quality of life, health, wellbeing and creativity and decrease in emotional and physical suffering for older people. This effect will not just be national but international. The research will also increase the awareness of others to the problems of ageing.

3) Economy.
This project will have an impact on the UK economy in several ways, both in short and long-term. Firstly, in the short-term, the project will create one new job as well as provide training thus creating a highly skilled worker for e.g. the pharmaceutical industry. In the long-term, reduction in public care costs will liberate funds for investment into the economy. New interventions for treatment of ageing-related disease that will be developed as a result of research initiated in this project will benefit the pharmaceutical industry and hence the economy. Treatments that extend health into old age will provide more work force aiding the economy. The project will raise the research profile of the UK leading to more investments by the pharmaceutical industry. All of these will have an effect of increasing the economic performance, competitiveness and reputation of the UK.

4) Government policy.
This project will have an impact on the UK government and its policy. In short term, this research will further establish if ageing is a viable target for treatment of age-related conditions, and if increased health and wellbeing can be achieved in older age, thus informing government policy on the feasibility of this approach and whether further funding in this area of scientific enquiry is required and justified. In the long-term, the effects on the health of older people may inform government policy in numerous important areas such as healthcare and pensions.