Unravelling the mechanism of transcellular chaperone signalling in C. elegans
Lead Research Organisation:
University of Leeds
Department Name: Sch of Molecular & Cellular Biology
Abstract
Age-related diseases including Alzheimer's, Parkinson's and Huntington's Disease is one of the biggest challenges for our aging society. The onset of these devastating diseases share a common feature, where unhealthy cells in the brain accumulate deformed proteins so-called misfolded proteins. To repair these proteins and restore health, cells have evolved a protective mechanism called stress responses where a family of proteins called chaperones will be produced to fix the damaged proteins.
My research using the round worm nematode C. elegans has demonstrated a novel inter-tissue communication that allows a stressed organ to send out an alert to healthy cells in other organs to instruct them producing more protective chaperones. This process is called transcellular chaperone signalling (TCS) and is also found in mammals. Currently, the key question for TCS and its mechanisms relevant to human diseases is to search for the "messenger" that regulates this inter-tissue communication. Our preliminary observation showed that PQM-1 (a protein factor that controls gene expression) and ASP-12 (a putative secretory molecule) both play a key role in TCS and stress response.
We are planning to understand how they function in these events and their roles in the onset of human diseases. Using C. elegans, we will build a new tool that will reveal the protective role of core chaperones in stress response across all tissues in the worms. We will monitor the chaperone expression during normal developmental processes, stress response and TCS to comprehensively understand how "transcellular chaperone expression" could be developed as a novel therapeutic approach to treat protein misfolding diseases. In other words, this means that we could activate protective chaperones from a healthy tissue which then "signals" to a tissue affected by disease (e.g. brain) to produce more protective chaperone. Our work will generate invaluable information that can be indicative to researchers using rodent models to study stress responses in an intact animal. Our approach will provide a great alternative tool to perform pilot studies in C. elegans prior the mammalian animal experiments. This approach will greatly reduce the amount of animals used in these kinds of experiments.
Our aim is to understand how cells cope with stress and how tissues communicate with each other to perform stress response. The innovative research conducted in our team will push the boundary to search for potential treatments for human diseases caused by the accumulation of mis-folded proteins.
My research using the round worm nematode C. elegans has demonstrated a novel inter-tissue communication that allows a stressed organ to send out an alert to healthy cells in other organs to instruct them producing more protective chaperones. This process is called transcellular chaperone signalling (TCS) and is also found in mammals. Currently, the key question for TCS and its mechanisms relevant to human diseases is to search for the "messenger" that regulates this inter-tissue communication. Our preliminary observation showed that PQM-1 (a protein factor that controls gene expression) and ASP-12 (a putative secretory molecule) both play a key role in TCS and stress response.
We are planning to understand how they function in these events and their roles in the onset of human diseases. Using C. elegans, we will build a new tool that will reveal the protective role of core chaperones in stress response across all tissues in the worms. We will monitor the chaperone expression during normal developmental processes, stress response and TCS to comprehensively understand how "transcellular chaperone expression" could be developed as a novel therapeutic approach to treat protein misfolding diseases. In other words, this means that we could activate protective chaperones from a healthy tissue which then "signals" to a tissue affected by disease (e.g. brain) to produce more protective chaperone. Our work will generate invaluable information that can be indicative to researchers using rodent models to study stress responses in an intact animal. Our approach will provide a great alternative tool to perform pilot studies in C. elegans prior the mammalian animal experiments. This approach will greatly reduce the amount of animals used in these kinds of experiments.
Our aim is to understand how cells cope with stress and how tissues communicate with each other to perform stress response. The innovative research conducted in our team will push the boundary to search for potential treatments for human diseases caused by the accumulation of mis-folded proteins.
Technical Summary
One of the major recent discoveries in the field of proteostasis, is the finding that protein quality control mechanisms in multicellular organisms are communicated between different tissues. Using C. elegans, I have shown that the regulation of chaperone expression is controlled cell-nonautonomously by transcellular chaperone signalling (TCS). A key observation of TCS is that mild tissue-specific stress, results in a compensatory activation of cyto-protective hsp-90 and hsp-70 chaperone expression in other tissues. Thus TCS has the potential to restore proteostasis in tissues affected by protein misfolding disease, such as neurodegenerative diseases. The mechanism of TCS is however not understood, and the "transcellular signaling factor" that is transmitted between tissues is unknown.
Using a system-wide approach and genetic analysis, I have identified the conserved transcription factor PQM-1, and a conserved secreted immune peptide (asp-12) targeted by PQM-1 as potential mediators of TCS. The precise role of this transcription factor and asp-12 in the regulation of organismal proteostasis and TCS is not understood. The objectives of this proposal are to: 1.) elucidate the PQM-1 chromatin binding profile during heat stress and tissue-specific stress that activates TCS; 2.) define a mechanistic basis of how PQM-1 and ASP-12 regulate TCS and the activation of chaperone expression between tissues; and 3.) establish C. elegans as a translatable model system, to investigate how TCS-mediated activation of chaperone expression restores proteostasis in tissues affected by protein misfolding diseases.
The immediate outcome will provide the underlying mechanism for TCS and establish asp-12 as a "transcellular signaling molecule". The C. elegans chaperone reporters will replace the use of mouse neurodegenerative disease models, to understand how TCS can be harnessed to restore proteostasis in tissues affected by protein misfolding diseases.
Using a system-wide approach and genetic analysis, I have identified the conserved transcription factor PQM-1, and a conserved secreted immune peptide (asp-12) targeted by PQM-1 as potential mediators of TCS. The precise role of this transcription factor and asp-12 in the regulation of organismal proteostasis and TCS is not understood. The objectives of this proposal are to: 1.) elucidate the PQM-1 chromatin binding profile during heat stress and tissue-specific stress that activates TCS; 2.) define a mechanistic basis of how PQM-1 and ASP-12 regulate TCS and the activation of chaperone expression between tissues; and 3.) establish C. elegans as a translatable model system, to investigate how TCS-mediated activation of chaperone expression restores proteostasis in tissues affected by protein misfolding diseases.
The immediate outcome will provide the underlying mechanism for TCS and establish asp-12 as a "transcellular signaling molecule". The C. elegans chaperone reporters will replace the use of mouse neurodegenerative disease models, to understand how TCS can be harnessed to restore proteostasis in tissues affected by protein misfolding diseases.
Planned Impact
The proposed work programme aims to demonstrate impact on the replacement and reduction of mouse models of neurodegenerative disease, such as Alzheimer's Disease. These pathologies are characterized by cumulative protein misfolding in an age-dependent manner. Molecular chaperones are key components of the proteostasis network that refold misfolded proteins. Overexpression of chaperones is often found to protect from the proteotoxic consequences of misfolded or aggregated disease proteins.
Both, overexpression of chaperones as well the expression of neurodegenerative disease proteins have been studied in the mouse since the mid-1990s, with approx. 100 research papers published each year (average between 1995 - 2015) and using an average of 400-600 mice for genetic manipulation and experimental procedures.
The discovery of "cell-nonautonomous proteostasis" in 2008, has led to new questions and directions of how chaperone biology and conformational protein-folding diseases are studied. Since 2008, the number of research papers using mice to study how chaperone overexpression can suppress the onset of disease has steadily increased from 75 papers per year in 2006, to 140 published papers in 2014. With the more recent finding in 2013 that protective chaperone expression can be regulated by transcellular chaperone signaling (TCS) this number of published papers using mice would be expected to further increase.
We will establish chaperone reporters that allow to study TCS-related processes in a range of neurodegenerative disease models in C. elegans before translating that research into the murine model system. This will allow to evaluate potential TCS mediators that activate cyto-protective chaperone expression across tissues and test whether this ameliorates the disease. Once established, two research labs using mouse models of neurodegenerative disease will utilise our collection of chaperone reporters as an alternative model system. This will replace the use of at least 120 mice in their research labs (see attached support letters from Dr. Prado and Dr. Dinkova-Kostova).
Assuming that the above number of 140 published papers is representative of an equal number of mouse research labs in the field, our alternative C. elegans chaperone reporters could save an average number of 100 mice per research paper. Thus our research would in theory save 14.000 mice per year. We will promote our chaperone reporters through several pathways including, 1) a dedicated website that provides comprehensive information on chaperone expression and protocols on how to adopt the chaperone reporters as a model system; 2) through an end-of-grant symposium to inform mouse and C. elegans researchers on the use of our chaperone reporters and 3) through workshop sessions during international chaperone conferences to reach a wider relevant audience. The international meetings are generally well attended by mouse research labs and we estimate that if we reach approx. 20 labs to use our chaperone reporters, this could realistically replace 2000 mice per year (100 mice per research paper x 20 labs).
Beyond the 3Rs impact our work programme will have a scientific impact in the field of proteostasis, as it will advance the field by providing a mechanistic basic for TCS along with the sought after "signaling molecule" that mediates TCS.
It will have an economic impact and value for money, as it will benefit proteostasis researchers using vertebrate models to design their experiments. This will reduce the amount of animals and produce significant savings through benefiting other publically funded research.
It will benefit highly skilled members of the UK work force as it will develop transferable skills of researchers involved in the project. Finally this work will benefit the general public at large, since understanding the mechanism for TCS has a large potential for the development ofnovel therapeutic strategies to cure protein misfolding disease.
Both, overexpression of chaperones as well the expression of neurodegenerative disease proteins have been studied in the mouse since the mid-1990s, with approx. 100 research papers published each year (average between 1995 - 2015) and using an average of 400-600 mice for genetic manipulation and experimental procedures.
The discovery of "cell-nonautonomous proteostasis" in 2008, has led to new questions and directions of how chaperone biology and conformational protein-folding diseases are studied. Since 2008, the number of research papers using mice to study how chaperone overexpression can suppress the onset of disease has steadily increased from 75 papers per year in 2006, to 140 published papers in 2014. With the more recent finding in 2013 that protective chaperone expression can be regulated by transcellular chaperone signaling (TCS) this number of published papers using mice would be expected to further increase.
We will establish chaperone reporters that allow to study TCS-related processes in a range of neurodegenerative disease models in C. elegans before translating that research into the murine model system. This will allow to evaluate potential TCS mediators that activate cyto-protective chaperone expression across tissues and test whether this ameliorates the disease. Once established, two research labs using mouse models of neurodegenerative disease will utilise our collection of chaperone reporters as an alternative model system. This will replace the use of at least 120 mice in their research labs (see attached support letters from Dr. Prado and Dr. Dinkova-Kostova).
Assuming that the above number of 140 published papers is representative of an equal number of mouse research labs in the field, our alternative C. elegans chaperone reporters could save an average number of 100 mice per research paper. Thus our research would in theory save 14.000 mice per year. We will promote our chaperone reporters through several pathways including, 1) a dedicated website that provides comprehensive information on chaperone expression and protocols on how to adopt the chaperone reporters as a model system; 2) through an end-of-grant symposium to inform mouse and C. elegans researchers on the use of our chaperone reporters and 3) through workshop sessions during international chaperone conferences to reach a wider relevant audience. The international meetings are generally well attended by mouse research labs and we estimate that if we reach approx. 20 labs to use our chaperone reporters, this could realistically replace 2000 mice per year (100 mice per research paper x 20 labs).
Beyond the 3Rs impact our work programme will have a scientific impact in the field of proteostasis, as it will advance the field by providing a mechanistic basic for TCS along with the sought after "signaling molecule" that mediates TCS.
It will have an economic impact and value for money, as it will benefit proteostasis researchers using vertebrate models to design their experiments. This will reduce the amount of animals and produce significant savings through benefiting other publically funded research.
It will benefit highly skilled members of the UK work force as it will develop transferable skills of researchers involved in the project. Finally this work will benefit the general public at large, since understanding the mechanism for TCS has a large potential for the development ofnovel therapeutic strategies to cure protein misfolding disease.
