Retinol Research Today is a free monthly online journal that collates and summarizes the latest research about Retinol, including details on vitamin a, uses, wrinkle treatment, anti-aging. | ||||||||
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Retinoic acid-dependent attraction of adult spinal cord axons towards regenerating newt limb blastemas in vitro.Dmetrichuk JM, Spencer GE, Carlone RL Department of Biology, Brock University, 500 Glenridge Avenue, St. Catharines, Ontario, Canada L2S 3A1. Adult urodele amphibians possess the unique ability to regenerate amputated limbs and to re-innervate these regenerating structures; however, the factors involved in mediating this re-innervation are largely unknown. Here, we investigated the role of retinoic acid (RA) and one of its receptors, RARbeta, in the reciprocal neurotropic interactions between regenerating limb blastemas and spinal cord explants from the adult newt Notophthalmus viridescens. First, we showed that retinoic acid induced directed axonal outgrowth from cultured spinal cord tissue. This RA-induced outgrowth was significantly reduced when spinal cord explants were pre-treated with either the synthetic RAR pan antagonist, LE540, or the specific RARbeta antagonist, LE135. The role of RARbeta was also investigated using co-cultured regenerating limb blastemas and spinal cord explants. Blastemas induced significantly more axonal outgrowth from the near side of co-cultured explants, than from the far side (when cultured less than 1 mm apart). This blastema-induced directed outgrowth from co-cultured spinal cord explants was also abolished in the presence of the RARbeta antagonist, LE135. These data strongly suggest that endogenous retinoic acid is one of the tropic factors produced by the blastema and that it may be capable of guiding re-innervating axons to their targets. Moreover, this interaction is likely mediated by the retinoic acid beta nuclear receptor. Published 25 April 2005 in Dev Biol, 281(1): 112-20.
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