James G. Tidball, Ph.D.

Work Address:
Terasaki Life Science Building
Molecular, Cellular & Integrative Physiology Program
Los Angeles, CA 90095 Dept of Pathology and Laboratory Medicine
Los Angeles, CA 90095

Distinguished Professor, Integrative Biology and Physiology, Pathology and Laboratory Medicine
Member, Brain Research Institute
Research Interests
Much of the research in my lab concerns the cell biology of muscle disease. We are particularly interested in the pathophysiology of muscular dystrophy that is caused by null mutations of the gene that encodes the membrane associated protein called dystrophin. Loss of dystrophin from humans causes the lethal, progressive disease called Duchenne muscular dystrophy (DMD). Although loss of dystrophin is the primary cause of DMD, the resulting muscle pathology is difficult to interpret in the simple context of loss of a single structural protein. Instead, current evidence tells us that the secondary loss of other, dystrophin-associated proteins is important in causing many of the pathological features of the disease. One of these dystrophin-associated proteins, called nitric oxide synthase (NOS), produces the important regulatory molecule NO, and its loss can result in misregulation of many vital processes and thereby contribute to the pathology of muscular dystrophy. Much of our current work is directed toward understanding the functions of NO in muscle and the relationships between NO defects and muscular dystrophy. We have also learned through our recent studies that the immune system contributes importantly to promoting the pathology of muscular dystrophy. We have found that both lymphoid and myeloid cells increase the death of dystrophic muscle, which suggests that immune-based therapeutics may provide a new approach to treating muscular dystrophy. Our continuing work on this project is directed toward elucidating the mechanisms through which the immune system, especially myeloid cells, causes death of dystrophic muscle. In addition, we are exploring the possibility that other subpopulations of myeloid cells may also promote regeneration of injured tissue, and provide insights into new therapeutic strategies.

Interactions between skeletal muscle and the immune system. A major project in our lab concerns the pathophysiology of muscular dystrophy (dystrophinopathy). Our research has shown that the immune system plays an important role in influencing the severity of muscular dystrophy, and that immune-based interventions can significantly reduce dystrophic muscle pathology and promote muscle regeneration. Our continuing efforts are directed toward identifying the key effector cells and molecules involved in influencing the course of the disease, and examining the interplay between those effectors. Our technical approaches include the generation and analysis of transgenic, dystrophic mice so that the effects of increased or decreased expression of selected effector molecules can be assessed. We also examine the systemic effects of experimental depletions of selected immune cell populations and the efficacy of selected, pharmaceutical interventions on the progress of the disease. In other studies, we are studying the mechanisms through which the immune system influences the wasting of skeletal muscle that occurs during aging, a process called sarcopenia. We are particularly interested in identifying the mechanisms through which specific populations of myeloid cells affect muscle wasting and regeneration, and identifying strategies to slow the wasting process.

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