Lysophospholipid receptor signaling: Lysophospholipids (LPs) are simple phospholipids that produce a range of cellular responses that can now be attributed to receptor-mediated mechanisms. Major examples of LPs including lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P), and multiple cognate G-protein coupled receptors have been identified; the first through studies of the embryonic brain. Targeted deletion of these receptors continues to lead to new insights on the physiological significance of this lipid-based signaling system, revealing previously unknown roles, particularly in the nervous system.
Aneuploidy, mosaicism and apoptosis: Programmed cell death (PCD) amongst neural progenitor cells (NPCs) has been identified as a prominent feature of embryonic nervous system development. It occurs within non-synaptic, proliferative zones rather than postmitotic regions, representing a distinct form of PCD compared to classical, synapse-mediated death, and is partially explained by caspase mechanisms. A surprising discovery from studying NPC and PCD was the identification of many aneuploid NPC, some with extreme forms of aneuploidy. These data demonstrate that many neural cells are genomically non-identical, producing brains that are, in fact, genetic mosaics. Current studies will determine the biological functions of aneuploidy in the brain, including apoptotic roles.
Garcia-Fernandez M, Castilla-Ortega E, Pedraza C, Blanco E, Hurtado-Guerrero I, Barbancho MA, Chun J, Rodriguez-de-Fonseca F, Estivill-Torrus G, Nunez LJ. Chronic immobilization in the malpar1 knockout mice increases oxidative stress in the hippocampus. epub ahead of print 2012 Jun 21.
Castilla-Ortega E, Pedraza C, Chun J, Fonseca FR, Estivill-Torrus G, Santin LJ. (2012) Hippocampal c-Fos activation in normal and LPA(1)-null mice after two object recognition tasks with different memory demands. Behav Brain Res. 232, 400-405.
Lin ME, Rivera RR, Chun J. (2012) Targeted deletion of LPA5 identifies novel roles for lysophosphatidic acid signaling in development of neuropathic pain. J. Biol. Chem. 287, 17608-17617.
Ye X, Diao H, Chun J. (2012) 11-deoxy prostaglandin F(2alpha), a thromboxane A2 receptor agonist, partially alleviates embryo crowding in Lpar3((-/-) females. Fertil. Steril. 97, 757-763.
Funke M, Xhao Z, Xu Y, Chun J, Tager AM. (2012) The lysophosphatidic acid receptor LPA1 promotes epithelial cell apoptosis following lung injury. Am. J. Respir. Cell. Mol. Biol. 46, 355-364.
Cheng HY, Dong A, Panchatcharam M, Mueller P, Yang F, Li Z, Mills G, Chun J, Morris AJ, Smyth SS. (2012) Lysophosphatidic acid signaling protects pulmonary vasculature from hypoxia induced remodeling. Arterioscler. Thromb. Vasc. Biol. 32, 24-32.