James L. Lessard, PhD
Title
Associate Director and Professor
Appointment
Professor of Pediatrics
Email
james.lessard@cchmc.org
Phone
513-636-8308
Fax
513-636-4317
Credentials
PhD: Marquette University, Milwaukee, Wisc., 1970.
Position History
- 1969-71 Postdoctoral Fellow, Biochemistry Department, Roche Institute of Molecular Biology
- 1971-72 Postdoctoral Fellow, Children's Hospital Research Foundation
- 1972-79 Assistant Professor of Research Pediatrics, University of Cincinnati
- 1974-present Faculty, Molecular and Developmental Biology Graduate Program, University of Cincinnati
- 1974-present Assistant Professor of Biological Chemistry, University of Cincinnati
- 1979 Associate Professor of Pediatrics, University of Cincinnati
- 1985-1989 Director of Graduate Studies, Developmental Biology Graduate Program, University of Cincinnati
- 1989-1995 Director, Developmental Biology Graduate Program, University of Cincinnati
- 1991-present Professor of Pediatrics
- 1995-2000 Interim Director, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center
- 2000-present Associate Director, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center
Awards and Honors
- 1961-1965 Academic Scholarship, Marquette University
- 1968-1969 Public Health Service Individual Predoctoral Fellowship Grant
- 1970-1971 Postdoctoral Fellowship, Roche Institute of Molecular Biology
- 1972-1974 Pharmacology-Morphology Fellowship, Pharmaceutical Manufacturers Association Foundation
- 1972-1976 Basil O'Connor Award, March of Dimes.
Research
Muscle development and functionA major line of study by James L. Lessard, Ph.D., is concerned with assessing the functional and developmental significance of the four distinct forms of muscle actins. Actin is a key protein that is involved in all forms of muscle contraction.
Four very similar but distinct actins comprise the major isoforms found in skeletal muscle, cardiac muscle, vascular smooth muscle, and enteric smooth muscle of adult vertebrates.
To date, however, there is little evidence to support the hypothesis that there are functional differences among the muscle actins that could account for the actin composition of a given muscle type.
Gene targeting strategies provide a powerful way to examine this issue by ablating individual actin genes. Dr. Lessard and his coworkers have disrupted the murine cardiac and skeletal actin genes by homologous recombination.
While the majority of the mice lacking cardiac actin do not survive to term, there is no fetal loss of animals lacking skeletal actin. In both cases all of the affected mice die as neonates. The skeletal actin deficient mice show a markedly lower body weight within 3 days and develop scoliosis.
Survival of both groups to birth and beyond appears to be due to compensatory increases in the levels of vascular smooth muscle and skeletal actins in their hearts or skeletal muscle.
In addition, the Lessard lab has rescued cardiac actin deficient mice to adulthood by first making transgenic mice that carry a cDNA sequence encoding the enteric form of the hearts of mice that completely lack cardiac actin.
The rescued hearts function very poorly with reduced rates of contraction and relaxation; they also are significantly enlarged and the cardiac muscle cells show some disarray and hypertrophy.
Importantly, transgenically expressed enteric actin also reduces cardiac contractility in wild-type and heterozygous null backgrounds.
Overall, these results show that severe structural and functional perturbations are associated with these alterations in the actin composition of skeletal or cardiac muscle and they support the hypothesis that the muscle actins are functionally specialized.
A second line of study is concerned with the regulation of smooth muscle growth and differentiation. During the past year, they have continued to focus on the identification of genetic elements required for the smooth muscle specific and developmentally regulated expression of the Smooth Muscle Gamma Actin (SMGA) gene in the lung and other tissues.
Sequence comparisons across species may identify conserved regions that will provide a clue for cis-regulatory elements. Unfortunately, little sequence was available for the SMGA gene in other species for such a comparison.
Thus, during the past year they cloned the chicken SMGA gene and we have extended the upstream sequence of the human enteric actin gene. Comparisons are under way to identify regions of homology between the upstream sequences of the mouse, human, and chicken SMGA genes.
Dr. Lessard's group is also making use of transgenic strategies to characterize a minimal segment of the SMGA gene that drives the appropriate temporal-spatial expression of linked genes. Such a reagent would be very useful for modifying smooth muscle.
Research Grants and Contracts
R01 HL57291
Dates: 01/1/97-03/31/05
Title: Targeted alteration of actin in the heart.
PI: J. Lessard
The project seeks to modify the actin composition of the heart by using a mouse model in which we have already ablated the cardiac actin gene. The lethal phenotype of these mice has been "rescued" by ectopically expressing smooth muscle gamma-actin in the heart using a cardiac alpha myosin promoter; however, the adult hearts are extremely hypertrophied and hypocontractile. The effects of replacements with skeletal, vascular and cardiac actin are being studied and the relative contributions of the type and amount of actin in the heart will be assessed. We are currently making mouse models of actin-based cardiomyopathy to examine the pathogenesis, progression, and compensatory mechanisms involved in these devastating disorders. Toward that end, we have generated transgenic mice carrying the following mutations in cardiac actin that are identical to the mutations in humans causing DCM (R312H and E361G) and FHC (A295S).
R01 DK61219
Dates: 02/01/02-01/31/06
Title: Hlx in Enteric Mesenchymal and Neuronal Development
PI: M. Bates
Role: Co-PI
This grant seeks to understand the genetic programs required for intestinal mesenchymal differentiation. The overarching hypothesis is that the Hlx transcription factor regulates intestinal mesenchymal differentiation and mesenchymal-neuronal interactions required for ENS development. We propose to first test the hypothesis that Hlx is required for normal migration and intestinal colonization of neural crest cells in mouse development. Our second aim is to test the hypothesis that Hlx is required for normal proliferation and/or differentiation of neural crest cells in mouse development. Finally, we will test the hypothesis that Hlx is required for development of primitive intestinal mesenchymal cells into smooth muscle cells, interstitial cells of Cajal, and subepithelial myofibroblasts. The proposed experiments will provide novel insights into the differentiation program of intestinal mesenchyme and enteric neurons and their regulation by the Hlx transcription factor.
PENDING
UO1 DK070219-01
Dates: 01/15/05-01/14/10
PI: J. Lessard
Title: Mouse Atlas of Genitourinary Smooth Muscle Development
This is a consortium initiative in response to PAR-04-042 entitled "Murine Atlas of Genitourinary Development." Currently, GU developmental research is limited by a paucity of cell specific markers for key lineages within the developing GU tract, incomplete understanding of the normal three dimensional cellular structure of the major organs of the GU tract, incomplete understanding of the morphogenetic events that occur during organogenesis, and the lack of a detailed integrative database to assimilate complex temporal and spatial expression data." To address these deficiencies, we propose to first characterize the morphological development of visceral smooth muscle associated with the murine GU tract using mice we have generated expressing fluorescent markers under the control of smooth muscle actin promoters. We will also develop an atlas of gene expression patterns that characterize distinct stages of differentiation in smooth muscle cells (SMCs) within GU tissues of the mouse. We will isolate highly enriched SMC populations from GU tissues using laser capture microdissection (LCM). It is expected that this approach will yield a high-resolution analysis of gene expression in specimens of smooth muscle from a number of genitourinary tissues through developmental time.
Publications, Most Recent
James Lessard's publications as listed by PubMed
Crawford, K, R Flick, L Close, D Shelly, R Paul, K Bove, A Kumar, J Lessard. Mice lacking skeletal muscle actin show reduced muscle strength and growth deficits and die during the neonatal period.Mol Cell Biol 22(16): 5887-96 (2002).
Martin, A F, R M Phillips, A Kumar, K Crawford, Z Abbas, J L Lessard, P de Tombe and R J Solaro. Ca(2+) activation and tension cost in myofilaments from mouse hearts ectopically expressing enteric gamma-actin.Am J Physiol Heart Circ Physiol 283(2): H642-9 (2002).
Vrhovszki, B, Schevzov, G, Dingle, S, Lessard, JL, Gunning, P, Weinberger, RP. Tropomyosin isoforms from the gamma gene differing at the C-terminus are spatially and developmentally regulated in the brain.J. Neurosci. Res. 72(3):373-83 (2003).
Abdewahid, E, Pelliniemi, LJ, Szucsik, JC, Lessard, JL, and Eero, J. Cellular disorganization and extensive apoptosis in the heart of mice lacking cardiac muscle alpha-actin: Apparent cause of perinatal death.Ped. Res. 55:1-8 (2003).
Szucsik, JC, Lewis, AG, Marmer, D and Lessard, JL. Urogenital Tract Expression of Enhanced Green Fluorescent Protein (EGFP) in Transgenic Mice Driven by a Smooth Muscle Gamma-Actin Promoter.J. Urol. 171(2):944-949 (2004).
Kumar, A, Crawford, K, Flick, R, Klevitsky, R, Lorenz, JN, Bove, KE, Robbins, J and Lessard, JL. Transgenic overexpression of cardiac actin in the mouse heart suggests coregulation of cardiac, skeletal and vascular actin expression.Transgenic Res. 13: 531-540 (2004)
Wilma A. Hofmann, Ljuba Stojiljkovic, Beata Fuchsova, Gabriela M. Vargas, Evangelos Mavrommatis, Vlada Philimonenko, Katarina Kysela, James A. Goodrich, James L. Lessard, Thomas J. Hope, Pavel Hozak and Primal de Lanerolle. Actin is part of pre-initiation complexes and required for transcription by RNA polymerase II.Nature Cell Biol 6:1094-1102 (2004).
Special Interests
gene regulation, gene targeting
Grants:1996-2001: National Institutes of Health, HL-SCOR in Pathobiology of Lung Development. Whitsett J (PI), Project 5: Smooth muscle cell differentiation and gene regulation during lung morphogenesis. Lessard JL (Project Leader)
1997-2002: National Institutes of Health (R01-HL57291), Targeted alteration of actin in the heart
1999-2000: Children's Hospital Research Foundation of Cincinnati Trustee Grant. Can the skeletal actin gene be exploited for gene therapy?
2000-2002: National Institutes of Health (1R21-DK57046), Transgenic remodeling of visceral smooth muscle
2000-2002: National Institutes of Health (1R21-DK59999), Approaches to Urogenital Smooth Muscle Development
Honors:
Academic Scholarship, Marquette University
Public Health Service, Individual Predoctoral Fellowship Grant
Postdoctoral Fellowship, Roche Institute of Molecular Biology
Pharmacology-Morphology Fellowship (Pharmaceutical Manufacturers Association Foundation)
March of Dimes Basil O'Connor Award
Professional Organizations:
American Society for Cell Biology
Society for Developmental Biology
American Association for the Advancement of Science
New York Academy of Science
Related Areas
This person works in these other areas at Cincinnati Children's Hospital Medical
Center:
