FAP-DMD: Elucidating the role of FAP cells in the process of muscle degeneration in patients with Duchenne muscular dystrophy
Lead Research Organisation:
Newcastle University
Department Name: Translational and Clinical Res Institute
Abstract
Duchenne muscular dystrophy (DMD) is a devastating disease produced by mutations in the dystrophin gene. Disease's onset with onset of weakness occurs before the age of 5 years and progresses leading to loose of ambulation during adolescence. Patients die during the third decade of life because of cardiac or respiratory complications. The only treatment approved so far is corticoids that slow down progression but without having a real impact in natural history. Despite huge efforts invested in developing new treatments, most of them have failed. At the moment, gene therapies based on the release of a healthy copy of the dystrophin gene to the muscle fibers are showing promising results, but it seems clear that they are not going to be able to stop disease's progression and that the process of muscle degeneration will remain active. The process of muscle degeneration in DMD has been studied for many years in animal models of the disease. Lack of dystrophin makes the fibers more susceptible to damage during normal muscle contraction. Damaged fibers are initially repaired by cells named satellite cells. However, repetitive damage triggers a series of consequences in the tissue including persistent infiltration by inflammatory cells that activates a type of cell known as fibro-adipogenic precursor cells (FAPs). FAPs contribute to muscle degeneration as they produce fat and fibrotic tissue which substitutes the damaged muscle fibers. During disease's progression, loss of fibers is associated to expansion of fibrotic and fatty tissue which impairs the capability of satellite cells to regenerate damaged muscle fibers. Although several molecules have been identified as key to regulate this process in mice, little is known in humans what is limiting the development of new treatments. We have developed a new protocol to isolate satellite cells and FAPs from muscle biopsies that were taken for diagnosis and are stored in biobanks. We have analyzed the cells obtained from DMD and healthy people and have identified different types of FAP cells. To summarize we have identified two main populations, one that is actively proliferating and retain stemness properties and another that is already committed to produce fibrotic tissue. In this proposal we will explore when these different populations appear in the progression of DMD patients using muscle biopsies of patients at different clinical stages and correlate their presence with tissue features to understand if these subpopulations are associated to changes such as fibrosis, inflammation or muscle fiber death. Then we will analyze the genes that are expressed in control and DMD muscle by fibers but also by other components, such as inflammatory cells, that could guide the changes in FAP subtype. Understanding the molecular pathways governing the changes in FAP subpopulations will provide potential new targets for therapies aimed to counteract the expansion of fibro-fatty tissue. In a third stage we will isolate the subpopulations of FAPs and study their properties including how they proliferate, move, or differentiate into fibrotic or fat producing cells and how they interact with satellite cells. These later studies provide information about how two cells interact in a dish, as it would happen when they are in the tissue. We will study this interaction both in standard 2D culture dishes, but also in 3D systems using printed molds that enable a more perdurable and structured generation of artificial muscles. These experiments will provide valuable information to understand if and how FAPs influence satellite cell function. Finally, we will test libraries of drugs able to counteract the function of key molecular pathways identified in the previous experiments to understand if they are able to modulate the function of FAPs.
Technical Summary
The process of muscle degeneration in Duchenne muscular dystrophy (DMD) has been extensively studied in mice. In recent years a new type of cell called fibro-adipogenic precursor cell (FAPs) has been discovered. These cells have a pivotal role in both muscle regeneration and degeneration regulating the function of other muscle stem cells and producing fibrotic and fat tissue contributing to muscle fiber lose. Research in murine models have generated candidate molecular targets for therapies although there is still a considerable 'translational gap' between these putative targets and effective therapies for patients. This is in part due to limited definition of the functional heterogeneity and interactome of cell lineages that contribute to the muscle degeneration, which is imperfectly recapitulated by rodent models. We have developed a new protocol to isolate FAPs and other muscle cells from muscle biopsies. We have already identified that there are different subpopulations of FAPs in DMD with a different gene expression profile whose function in completely unknown. We will isolate these subpopulations and study their biological properties and how these cells interact with other muscle resident cells. Additionally, we will study the temporal dynamics of FAP subpopulations through the progression of the disease and the molecular pathways governing changes in their phenotype. These experiments will identify molecular targets for the development of new therapies that could influence FAP cells function. In this sense, we have recently identified a series of drugs that slowed down disease progression in mice. We will test these drugs in the cells obtained from patients to confirm their effectivity in humans as a preliminary step to trials. In summary, we aim to characterize the role of different subpopulations of FAP cells in DMD patients to discover new putative molecular targets for developing new therapies to slow down the progression of this devastating disorder.
Publications
Alonso-Pérez J
(2022)
Nintedanib Reduces Muscle Fibrosis and Improves Muscle Function of the Alpha-Sarcoglycan-Deficient Mice.
in Biomedicines
Carrasco-Rozas A
(2022)
BNIP3 Is Involved in Muscle Fiber Atrophy in Late-Onset Pompe Disease Patients.
in The American journal of pathology
Esteller D
(2023)
Muscle magnetic resonance imaging of a large cohort of distal hereditary motor neuropathies reveals characteristic features useful for diagnosis
in Neuromuscular Disorders
Esteller D
(2023)
Analysis of muscle magnetic resonance imaging of a large cohort of patient with VCP-mediated disease reveals characteristic features useful for diagnosis.
in Journal of neurology
Fernández-Simón E
(2022)
RhoA/ROCK2 signalling is enhanced by PDGF-AA in fibro-adipogenic progenitor cells: implications for Duchenne muscular dystrophy.
in Journal of cachexia, sarcopenia and muscle
Piñol-Jurado P
(2024)
Imaging mass cytometry analysis of Becker muscular dystrophy muscle samples reveals different stages of muscle degeneration.
in Scientific reports
Suárez-Calvet X
(2023)
Decoding the transcriptome of Duchenne muscular dystrophy to the single nuclei level reveals clinical-genetic correlations
in Cell Death & Disease
Tejedera-Villafranca A
(2023)
Mimicking sarcolemmal damagein vitro: a contractile 3D model of skeletal muscle for drug testing in Duchenne muscular dystrophy.
in Biofabrication
Description | Pediatric Cell Atlas of Skeletal Muscle |
Amount | $50,204 (USD) |
Organisation | Chan Zuckerberg Initiative |
Sector | Private |
Country | United States |
Start | 06/2022 |
End | 05/2025 |
Description | Transcript-MND: Transcribing the process of muscle degeneration in patients with motor neuron diseases |
Amount | € 202,710 (EUR) |
Funding ID | 24341 |
Organisation | French Muscular Dystrophy Association (AFM) |
Sector | Charity/Non Profit |
Country | France |
Start | 09/2022 |
End | 08/2024 |
Title | Protocol for isolating nuclei from muscle samples of patients |
Description | We have develop a protocol to isolate nuclei from muscle samples frozen and prepare them for snRNAsequencing. |
Type Of Material | Technology assay or reagent |
Year Produced | 2023 |
Provided To Others? | No |
Impact | This is not yet published, but the manuscript has been already submitted for publication |
Title | Scripts for the analysis of snRNAseq data |
Description | We have developed our own scripts for the analysis of the snRNAseq data generated |
Type Of Material | Technology assay or reagent |
Year Produced | 2023 |
Provided To Others? | No |
Impact | Script included in a paper that has been submitted |
Title | Scripts for the analysis of snRNAseq data |
Description | We have created new algorithms for the analysis of snRNAseq data. |
Type Of Material | Computer model/algorithm |
Year Produced | 2023 |
Provided To Others? | No |
Impact | The script is included in a paper that we have just submitted |
Description | Collaboration with Dr. Juanma Fernández-Costa from IBEC Institute in Barcelona |
Organisation | Institute for Bioengineering of Catalonia |
Country | Spain |
Sector | Private |
PI Contribution | We are collaborating with this researcher in developing a 3D cell muscle-on-a-chip model for DMD using immortalized FAPs and myoblasts. We have contributed with cells obtained and characterized in our lab but also advised on the antibodies to use for identifying cells. |
Collaborator Contribution | The collaborators are developing the 3D cell models with our cells to characterize if FAPs contribute to the development of the tissue and if DMD FAPs disrupt the function of these aritificial muscles. Once the model is developed we will test our drugs in the cell model. |
Impact | No output sou far as we are still working in the development of the model |
Start Year | 2022 |
Description | Collaboration with Hospital Sant Joan de Deu to obtain muscle samples for snRNAseq |
Organisation | Hospital Sant Joan de Deu |
Country | Spain |
Sector | Hospitals |
PI Contribution | We have collaborated by performing snRNAseq of the samples obtained from Hospital Sant Joan de Deu |
Collaborator Contribution | The Neuromuscular Disorders Unit of the Neurology department of Hospital Sant Joan De Deu has contributed to this project by obtaining muscle samples of patients with DMD with genetic confirmation |
Impact | Single nuclei RNA sequencing analysis of the muscle samples obtained |
Start Year | 2022 |
Description | Immortalization of FAP cells |
Organisation | Institute of Myology |
Country | France |
Sector | Hospitals |
PI Contribution | This is an active collaboration between laboratory of Dr. Vincent Mouly at Institute du Myologie and our group to immortalize FAP cells obtained from muscle samples of patients with neuromuscular diseases. Our contribution consist on obtaining cells from the muscle samples in our lab from patients with a genetic diagnosis of a neuromuscular disease. |
Collaborator Contribution | Our partners collaborate by immortalizing the cells that we obtain for the research. |
Impact | Immortalized FAPs from controls and patients with neuromuscular diseases |
Start Year | 2022 |
Description | Genetic Matters |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | Genetic Matters was a educational activity organized by the University of Newcastle for general public with the aim to increase the knowledge on genetic diseases and showcase the different activities/research performed at the University. Our group participated in that activity |
Year(s) Of Engagement Activity | 2023 |
Description | LGMD patient day |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Patients, carers and/or patient groups |
Results and Impact | We organized a LGMD patient day providing information to patients about diagnosis, new therapies and the research performed in our centre |
Year(s) Of Engagement Activity | 2023 |