Recombinant Human Nerve Growth Factor Treatment Promotes Photoreceptor Survival in the Retinas of Rats with Retinitis Pigmentosa.

PURPOSE: Increasing evidence suggests that nerve growth factor (NGF) exerts protective effects against retinal degeneration in animal models of retinitis pigmentosa (RP). This study aims at investigating the effects of intravitreal injection of recombinant human NGF (rhNGF) on retinal photoreceptors apoptosis in an animal model of RP, the Royal College of Surgeons (RCS) rats. METHODS: Thirty-six RCS rats were treated with intravitreal injection of rhNGF or murine NGF (mNGF) or vehicle at 20 postnatal days (pd) and sacrificed at 40 pd. The eyes were enucleated and evaluated by histology, flow cytometric analysis for rhodopsin expression, Western blot for TrkA and activated (phosphorylated) TrkA (pTrkA) levels, and TUNEL assay for apoptosis' detection. RESULTS: RCS rats showed a significant retinal degeneration associated with cell apoptosis at 40 pd when compared to wild-type animals. Histology showed that rhNGF intravitreal treatment significantly increased retinal thickness when compared to untreated eyes. Photoreceptors' number evaluated by flow cytometry was significantly increased in both intravitreal rhNGF- and mNGF-treated groups when compared to untreated eyes. This protective effect was associated with an increase in TrkA and activated pTrkA levels and an inhibition of apoptosis. Intravitreal NGF injection was well tolerated and did not show clinical and histological signs of adverse effects. CONCLUSIONS: Intravitreal rhNGF injection proved safe and effective in favoring retinal cell survival in RCS rats. This is the first report showing that the novel rhNGF already proved safe in a phase I study exerts a biologic effect similar to the well-characterized mNGF-induced retinal protection. These results may trigger further studies to investigate rhNGF administration for the treatment of progressive degenerative retinal disorders such as retinitis pigmentosa.

Analyses of Sox-B and Sox-E Family Genes in the Cephalopod Sepia officinalis: Revealing the Conserved and the Unusual.

Cephalopods provide an unprecedented opportunity for comparative studies of the developmental genetics of organ systems that are convergent with analogous vertebrate structures. The Sox-family of transcription factors is an important class of DNA-binding proteins that are known to be involved in many aspects of differentiation, but have been largely unstudied in lophotrochozoan systems. Using a degenerate primer strategy we have isolated coding sequence for three members of the Sox family of transcription factors from a cephalopod mollusk, the European cuttlefish Sepia officinalis: Sof-SoxE, Sof-SoxB1, and Sof-SoxB2. Analyses of their expression patterns during organogenesis reveals distinct spatial and temporal expression domains. Sof-SoxB1 shows early ectodermal expression throughout the developing epithelium, which is gradually restricted to presumptive sensory epithelia. Expression within the nervous system appears by mid-embryogenesis. Sof-SoxB2 expression is similar to Sof-SoxB1 within the developing epithelia in early embryogenesis, however appears in largely non-overlapping expression domains within the central nervous system and is not expressed in the maturing sensory epithelium. In contrast, Sof-SoxE is expressed throughout the presumptive mesodermal territories at the onset of organogenesis. As development proceeds, Sof-SoxE expression is elevated throughout the developing peripheral circulatory system. This expression disappears as the circulatory system matures, but expression is maintained within undifferentiated connective tissues throughout the animal, and appears within the nervous system near the end of embryogenesis. SoxB proteins are widely known for their role in neural specification in numerous phylogenetic lineages. Our data suggests that Sof-SoxB genes play similar roles in cephalopods. In contrast, Sof-SoxE appears to be involved in the early stages of vasculogenesis of the cephalopod closed circulatory system, a novel role for a member of this gene family.

Characterization of homeobox genes reveals sophisticated regionalization of the central nervous system in the European cuttlefish Sepia officinalis.

Cephalopod mollusks possess a number of anatomical traits that often parallel vertebrates in morphological complexity, including a centralized nervous system with sophisticated cognitive functionality. Very little is known about the genetic mechanisms underlying patterning of the cephalopod embryo to arrive at this anatomical structure. Homeodomain (HD) genes are transcription factors that regulate transcription of downstream genes through DNA binding, and as such are integral parts of gene regulatory networks controlling the specification and patterning of body parts across lineages. We have used a degenerate primer strategy to isolate homeobox genes active during late-organogenesis from the European cuttlefish Sepia officinalis. With this approach we have isolated fourteen HD gene fragments and examine the expression profiles of five of these genes during late stage (E24-28) embryonic development (Sof-Gbx, Sof-Hox3, Sof-Arx, Sof-Lhx3/4, Sof-Vsx). All five genes are expressed within the developing central nervous system in spatially restricted and largely non-overlapping domains. Our data provide a first glimpse into the diversity of HD genes in one of the largest, yet least studied, metazoan clades and illustrate how HD gene expression patterns reflect the functional partitioning of the cephalopod brain.