Chemical reversion of nuclear shape and other defects of Hutchinson Gilford Progeria Syndrome and Lamin A/C depleted cells

Human cells are highly organised and regulated, and any change in this organisation can have an effect at the level of the entire body. In recent years, it has become evident that one crucial part of the cell is a structure called the nuclear lamina, which surrounds the cell nucleus. This lamina structure, which is made up of proteins called lamins, is crucial for maintaining normal cell structure and function. Indeed, lamins act as a scaffold for maintaining nuclear architecture and nuclear shape.

Misregulation of the LMNA gene encoding for lamin proteins can occur through mutations, and leads to various human diseases, including muscular diseases and premature ageing syndromes called progerias. The common characteristic of these syndromes is misshapen cell nuclei due to the fact that the lamin proteins are not functional and cannot maintain normal nuclear morphology. The effects at the level of the entire body are predominantly found in the muscles and heart because, in these organs, the nuclear architecture is required for cells to survive repeated contractions. Consequently, patients with defects in the LMNA gene commonly die early from heart attacks because the function of their cardiac cells is strongly affected. Interestingly, misregulation of LMNA is also associated with normal ageing, and the nuclei of cells in old people appear to be misshapen compared to ones from young individuals.

In addition, lamin proteins are also misexpressed in various human cancers. One model is that the change in lamin expression in some cancers could contribute to the cell morphology defects that account for the invasiveness of cancer.

The fact that LMNA deregulation is associated with a broad range of human diseases, as well as with normal ageing, has triggered a strong interest in trying to rescue the misshapen nuclei in laminopathies, to improve global cellular fitness and patient survival. Unfortunately, currently there is no cure for these diseases, and the available therapies mainly act by improving the symptoms of these patients. In this proposal, we describe how we plan to characterize a new molecule that rescues the morphological defects of normal and premature ageing cell lines as well as Lamin A/C depleted cells. Indeed, recent work from our lab suggests that this molecule might improve the global cellular fitness of these cells. Thus, gaining insights into how this molecule works could help us understand the laminopathies and give us some important information about how to rescue the nuclear shape defects arising from LMNA misregulation. To this end, we aim to use a combination of biochemical, genetic and cell culture studies. We believe that this work could improve our fundamental knowledge of these diseases and could also suggest new ways of treating them. Moreover, this work could also open up new perspectives into improving normal age-related pathologies, which would of course have a great impact on public health.

One of the features shared by laminopathies is the disorganization of chromatin structure and misshapen nuclei. Hence, one of the main challenges is to identify new therapeutic strategies to reverse the nuclear shape defects in progeric and dystrophic cells to improve the patient's lifespan. This project investigates the mechanisms by which a new small molecule that we have called Remodelin rescues the nuclear morphology in progeric and dystrophic cells as well as in normal ageing cells. By modifying Remodelin to make it suitable for use with "click-chemistry", we have identified its cellular target responsible for the nuclear shape rescue. We will use a combination of in vitro assays, such as Biacore-based studies, to understand how the binding of Remodelin modulates the function of its target. We will then study in depth the mechanism by which Remodelin's impact on the target protein to rescue nuclear architecture. Next, by using cells derived from Hutchinson Gilford Progeria Syndrome (HGPS) patients, as well as normal ageing cells and Lamin A/C depleted cells, we will assess the effects of Remodelin treatment on nuclear architecture related functions, such as chromatin organization, cellular proliferation and DNA repair as well as cell motility and invasiveness potential. This will tell us whether Remodelin improves global cellular fitness in these different models. Finally, after defining these parameters in cellular systems, we will carry out in vivo assays with sophisticated mouse models comprising premature ageing HGPS mice as well as a Lamin A/C knock out mouse model of muscular dystrophy. These will be treated with Remodelin and its derivatives to see whether we can improve their phenotypes such as muscular and heart functions, bone density and weight as well as their global lifespan. Our work will thus shed light on a very challenging area of research - nuclear architecture associated diseases, which is likely in the longer term to influence public health.

Thanks to the great working environment provided in Cambridge, as well as the scientific network established by Prof. Jackson, the lab is highly competitive and often publishes important new results in high impact factor journals (please see indicators listed in the above section "communication plan"). It is internationally renowned and has established connections with numerous laboratories in Europe and elsewhere in the world. The Jackson laboratory has been a member of European Union Frameworks and Networks, thus contributing to increasing the attractiveness of Europe for researchers interested in the proposed research area. Indeed, his laboratory is currently a member of the Seventh Framework Health Research Programme (FP7) DDResponse (the DNA damage response and breast cancer), supported by the European Union that aims to exploit the DNA damage response (DDR) to assess and predict individual susceptibility and response focused on breast cancer and breast cancer therapies. It is also a member of CANGENIN (Cancer and Control of Genomic Integrity), a network of research groups in the fields of genomic integrity, transcriptional control and cancer epigenetics, and the Genome Stability Network and collaborates with numerous European research groups within these networks. Additionally, he collaborates with various European scientists not in the above-named networks. The Jackson laboratory's connection with the pharmaceutical sector also contributes to the attractiveness of the lab for researchers interested in dedicating their expertise and careers to the discovery of drugs that could be extremely important for treating DNA-damage associated diseases, such as cancer and premature ageing syndromes.

It has been shown that premature ageing syndromes such as Progeria syndromes recapitulate normal ageing in terms of nuclear architecture defects and decrease of cellular fitness. Our research aims at understanding how these defects can be rescued and to determine how this may improve global cellular fitness. Consequently, we strongly believe that the results arising from our research will have a significant impact in a number of different areas:

- It will impact on academics working in the fields of nuclear architecture, chromatin organization, DNA damage and cancer.
- Our results will shed light on how nuclear architecture defects can affect chromatin organization, cell proliferation and migration and endogenously arising DNA damage.
- It will impact on laminopathy-related fields of study.
- It will impact on researchers studying cellular and organism ageing.
- The results arising from our research will provide insights into how to rescue nuclear architecture defects in laminopathies and could thus not only help us understand these diseases but may also suggest new ways of treating these incurable diseases in the longer term.
- Premature ageing diseases are associated with the same nuclear architecture defects as those arising during normal ageing. Our research might thus provide important information on how to improve the global cellular fitness in both premature and normal ageing.
- Our findings may be of great value to the global health system in suggesting ways to improve the health and quality of life of the elderly.
- Consequently, our work may in the longer term directly impact on the elderly population.
- Our work will be of interest for non-scientific people, especially for the elderly, since it will help explain the mechanisms of ageing and age-related pathologies.
- Our research might open new perspectives on how to delay age-associated phenotypes and signs of ageing, and could thus be of great interest to the pharma, biotech and cosmetics industries which might wish to exploit our findings to benefit human health and quality-of-life, and for commercial benefit for UK-based organizations.