The core research aim of the Zammit group is to understand the regulation of <strong>stem cell</strong> function in both normal and diseased <strong>skeletal</strong>&nbsp;<strong>muscle</strong>. The functional unit of skeletal muscle is the myofibre: a giant syncytial cell maintained by hundreds of myonuclei. Growth, maintenance or repair of the post-mitotic myofibre is performed by<strong> satellite cells.</strong> These resident stem cells are located on the surface of the muscle fibre, below the surrounding basal lamina. <br /> <br /> Skeletal muscle is an archetypal adult stem cell model: maintenance and repair of functionally specialised post-mitotic cells is achieved by recruitment of undifferentiated precursors. Therefore, skeletal muscle provides an accessible model system with which to investigate adult stem cell control and function.<br /> <br /> Research into satellite cell function is also relevant to understanding muscle diseases. <strong>Muscular dystrophies </strong>are all characterised by progressive skeletal muscle weakness and wasting, and have been mapped to at least 31 genetic loci. While muscular dystrophies vary in: age of onset; muscles affected and severity, the common factor is that the primary genetic defect ultimately results in muscle wasting, meaning that the homeostatic/regenerative process carried out by satellite cells is gradually compromised. By investigating the regulation of satellite cell function we can increase our understanding of why satellite cells initially maintain muscle function but then gradually fail in dystrophic conditions. <br /> <br /> Theoretically, manipulation of the satellite cell pool in dystrophic muscle could both augment and prolong muscle function. This also has the advantage that it maintains a muscle environment still capable of responding to other forms of therapeutic intervention.<br /> <br /> Current projects fall into 3 broad categories.<br /> <br /> Signalling networks that regulate satellite cell activation and self-renewal &ndash; with particular emphasis on lipid and BMP pathways.<br /> <br /> The satellite cell contribution to muscular dystrophies &ndash; how satellite cell dysfunction contributes to disease progression in Emery-Dreifuss muscular dystrophy, Facioscapulahumoural muscular dystrophy and Oculopharyngeal muscular dystrophy, amongst others.<br /> <br /> The role of Pax genes &ndash; how Pax3 and Pax7 control satellite cells and their involvement in alveolar rhabdomyosarcoma.

Regulation of stem cell function in healthy and diseased muscle