Muscle stem cells are a potent cell population dedicated to efficacious skeletal muscle regeneration, but their therapeutic utility is currently limited by mode of delivery. We developed a cell delivery strategy based on a supramolecular liquid crystal formed by peptide amphiphiles (PAs) that encapsulates cells and growth factors within a muscle-like unidirectionally ordered environment of nanofibers. The stiffness of the PA scaffolds, dependent on amino acid sequence, was found to determine the macroscopic degree of cell alignment templated by the nanofibers in vitro. Furthermore, these PA scaffolds support myogenic progenitor cell survival and proliferation and they can be optimized to induce cell differentiation and maturation. We engineered an in vivo delivery system to assemble scaffolds by injection of a PA solution that enabled coalignment of scaffold nanofibers with endogenous myofibers. These scaffolds locally retained growth factors, displayed degradation rates matching the time course of muscle tissue regeneration, and markedly enhanced the engraftment of muscle stem cells in injured and noninjured muscles in mice.
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http://dx.doi.org/10.1073/pnas.1708142114 | DOI Listing |
Nat Commun
December 2024
Experimental Medicine & Immunotherapeutics, University of Cambridge, Cambridge, UK.
We describe a structural and functional study of the G protein-coupled apelin receptor, which binds two endogenous peptide ligands, apelin and Elabela/Toddler (ELA), to regulate cardiovascular development and function. Characterisation of naturally occurring apelin receptor variants from the UK Genomics England 100,000 Genomes Project, and AlphaFold2 modelling, identifies T89 as important in the ELA binding site, and R168 as forming extensive interactions with the C-termini of both peptides. Base editing to introduce an R/H168 variant into human stem cell-derived cardiomyocytes demonstrates that this residue is critical for receptor binding and function.
View Article and Find Full Text PDFStem Cell Res
December 2024
Cardiology Section, Medical Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA; Radiology Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA; Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA; Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA; Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA.
Coronary artery vasospasm (CAV) is characterized by transient constriction of epicardial coronary arteries leading to angina. Its disease mechanisms are multifactorial but has centered mostly on endothelial dysfunction and smooth muscle hyperreactivity. To facilitate the investigation of these mechanisms in cell culture, we generated and characterized three induced pluripotent stem cell (iPSC) lines from patients with CAV.
View Article and Find Full Text PDFStem Cell Res
December 2024
Institute of Physiology I, Medical Faculty, University of Bonn, Germany. Electronic address:
BAG3 contributes to the maintenance of proteostasis through chaperone-assisted selective autophagy. This function is impaired by a single amino acid exchange (P209L) in the protein, which causes myofibrillar myopathy-6 (MFM6). This disease manifests as severe skeletal muscle weakness, neuropathy and restrictive cardiomyopathy.
View Article and Find Full Text PDFAm J Physiol Cell Physiol
December 2024
Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
Cellular senescence has been implicated in the aging-related dysfunction of satellite cells, the resident muscle stem cell population primarily responsible for the repair of muscle fibres. Despite being in a state of permanent cell cycle arrest, these cells remain metabolically active and release an abundance of factors that can have detrimental effects on the cellular microenvironment. This phenomenon is known as the senescence-associated secretory phenotype (SASP), and its metabolic profile is poorly characterized in senescent muscle.
View Article and Find Full Text PDFAm J Physiol Cell Physiol
December 2024
Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
Plasma membrane repair (PMR) restores membrane integrity of cells, preventing cell death in vital organs, and has been studied extensively in skeletal muscle. Dysferlin, a sarcolemmal Ca-binding protein, plays a crucial role in PMR in skeletal muscle. Previous studies have suggested that PMR employs membrane trafficking and membrane fusion, similar to neurotransmission.
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