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Jérôme Lapointe, Ph.D.

Research Scientist

Agriculture and Agri-Food Canada

Dairy and Swine R & D Centre

2000, rue Collège

Sherbrooke, Québec

J1M 0C8

Telephone : 819-780-7219

Fax: 819-564-5507

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Research interests :

  • Female reproductive aging
  • Oxidative stress and female reproductive tract
  • Mitochondrial function and fertility
  • Sows reproductive potential and longevity
  • Antioxidants
  • Energy metabolism
  • Nutrigenomics

 

Summary of research program:

Reproductive performance, susceptibility to diseases and longevity could all be largely affected by the actions of reactive oxygen species (ROS) in mammals. ROS, including free radicals, are mainly generated as normal by-products of aerobic respiration and metabolism by mitochondria. These molecules can inflict serious damage to cellular constituents, such as lipids, nucleic acids, and proteins and likely perturb various cellular and physiological processes. Exposure to ROS appears to be unavoidable for cells living in an aerobic environment, and ROS toxicity is controlled by a complex network of non-enzymatic and enzymatic antioxidants. Therefore, oxidative stress can be defined as any imbalance between the production and the detoxification of ROS. Oxidative stress has increasingly emerged as a promoter of several reproductive disorders, such as anovulation, spontaneous abortions, abnormal embryonic development, fetal growth restriction, preterm labour and low birth weight. However, the toxicity of ROS is only one aspect of their action in living cells as ROS originating from mitochondria and other cellular sites can also modulate the function of various signalling pathways. A minimal amount of ROS is thus crucial to achieve good reproduction performance either in males than females. In all cells, mitochondria are remarkably dynamic organelles that participate in diverse cellular processes including calcium homeostasis, fatty acid oxidation, signal transduction and apoptosis but are mainly known as the primary energy-generating system. Given their central roles in energy metabolism and ROS production, mitochondria are important determinants of normal mammalian oogenesis, fertilization, embryo development, implantation and lactation in many species including pigs. Therefore, we hypothesized that reproductive function and health of sows should be improved with experimental approaches based on dietary supplementation with molecules or nutrients known for their antioxidant and/or energetic properties. We are thus developing new mitochondrial targeted nutritional strategies in order to enhance their reproductive potential and longevity. We are also performing in depth characterization of the cellular and molecular changes affecting sow’s reproductive tissues and associated with decline of fertility and aging.

 

Publications:

Hekimi S, Lapointe J, and Wen Y. 2011. Taking a "good" look at free radicals in the aging process. Trends Cell Biol. 2011 Oct;21(10):569-76.

Zheng H, Lapointe J, Hekimi S. 2010. Lifelong protection from global cerebral ischemia and reperfusion in long-lived Mclk1+/- mutants. Exp Neurol. 223(2):557-65.

Lapointe, J., and Hekimi, S. 2010. When a theory of aging ages badly. Cell. Mol. Life. Sci. 67(1):1-8.

Lapointe, J., Stepanyan Z., Bigras, E. and Hekimi, S. 2009. Reversal of the mitochondrial phenotype and slow development of oxidative biomarkers of aging in long-lived Mclk1+/- mice. J Biol Chem. 284(30):20364-74.

Lapointe, J., and Hekimi, S. 2008. Early mitochondrial dysfunction in long-lived Mclk1 +/- mice. 2008. J Biol Chem. 283 (38): 26217–26227.

Lapointe, J., Roy, M., St-Pierre, I., Kimmins, S., MacLaren, LA., and Bilodeau JF. 2006. Hormonal and region-specific regulation of nitric oxide synthases (nNOS, iNOS and eNOS) expression in the oviducts. Endocrinology.147(12):5600-10.

Lapointe, J., Kimmins, S., MacLaren, LA., and Bilodeau JF. 2005. Estrogen selectively up-regulates the phospholipid hydroperoxide glutathione peroxidase (PHGPx) in the oviducts. Endocrinology. 146(6):2583-92.

Lapointe, J. ,Tabariès, S. (co-auteurs), Besch, T., Carter, M., Woollard, J., Tuggle, CK., and Jeannotte, L. 2005. Cdx protein interaction with Hoxa5 regulatory sequences contributes to Hoxa5 regional expression along the axial skeleton. Mol Cell Biol. 25(4):1389-401.

Lapointe, J., and Bilodeau JF. 2003. Antioxidant defenses are modulated in the cow oviduct during the estrous cycle. Biol Reprod. 68(4):1157-64.

Aubin, J., Lemieux, M., Moreau, J., Lapointe, J., and Jeannotte L. 2002. Cooperation of Hoxa5 and Pax1 genes during formation of the pectoral girdle. Dev Biol. 244 : 96-113.