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The role played by autophagy after ischemia/reperfusion (I/R) in the retina remains unknown. Our study investigated whether ischemic injury in the retina, which causes an energy crisis, would induce autophagy. Retinal ischemia was induced by elevation of the intraocular pressure and modulation of autophagic markers was analyzed at the protein levels in an early and late phase of recovery. Following retinal ischemia an increase in LC3BII was first observed in the early phase of recovery but did not stay until the late phase of recovery. Post-ischemic induction of autophagy by intravitreal rapamycin administration did not provide protection against the lesion induced by the ischemic stress. On the contrary, an increase in the number of apoptotic cells was observed following I/R in the rapamycin treated retinas. [ABSTRACT FROM AUTHOR]

The molecular diagnosis of retinal dystrophies (RD) is difficult because of genetic and clinical heterogeneity. Previously, the molecular screening of genes was done one by one, sometimes in a scheme based on the frequency of sequence variants and the number of exons/length of the candidate genes. Payment for these procedures was complicated and the sequential billing of several genes created endless paperwork. We therefore evaluated the costs of generating and sequencing a hybridization-based DNA library enriched for the 64 most frequently mutated genes in RD, called IROme, and compared them to the costs of amplifying and sequencing these genes by the Sanger method. The production cost generated by the high-throughput (HT) sequencing of IROme was established at CHF 2,875.75 per case. Sanger sequencing of the same exons cost CHF 69,399.02. Turnaround time of the analysis was 3 days for IROme. For Sanger sequencing, it could only be estimated, as we never sequenced all 64 genes in one single patient. Sale cost for IROme calculated on the basis of the sale cost of one exon by Sanger sequencing is CHF 8,445.88, which corresponds to the sale price of 40 exons. In conclusion, IROme is cheaper and faster than Sanger sequencing and therefore represents a sound approach for the diagnosis of RD, both scientifically and economically. As a drop in the costs of HT sequencing is anticipated, target resequencing might become the new gold standard in the molecular diagnosis of RD. [ABSTRACT FROM AUTHOR]

■ Corneal dystrophies represent a highly heterogeneous group of hereditary disorders, consisting of more than 30 distinct entities, of which only 16 have their molecular basis partially or completely elucidated. The genetic characterization of corneal dystrophies revealed both genetic heterogeneity, i.e. different genes (KRT3 and KRT12) causing one single dystrophic phenotype, as well as phenotypic heterogeneity with one single gene (TGFBI) causing different dystrophic phenotypes (see below 5.5 keratoepithelinopathies). [ABSTRACT FROM AUTHOR]

Retinitis pigmentosa (RP) is a heterogeneous group of genetic disorders leading to blindness, which remain untreatable at present. Rd1 mice represent a recognized model of RP, and so far only GDNF treatment provided a slight delay in the retinal degeneration in these mice. Bmi1, a transcriptional repressor, has recently been shown to be essential for neural stem cell (NSC) renewal in the brain, with an increased appearance of glial cells in vivo in Bmi1 knockout (Bmi1-/-) mice. One of the roles of glial cells is to sustain neuronal function and survival. In the view of a role of the retinal Müller glia as a source of neural protection in the retina, the increased astrocytic population in the Bmi1-/- brain led us to investigate the effect of Bmi1 loss in Rd1 mice. We observed an increase of Müller glial cells in Rd1-Bmi1-/- retinas compared to Rd1. Moreover, Rd1-Bmi1-/- mice showed 7-8 rows of photoreceptors at 30 days of age (P30), while in Rd1 littermates there was a complete disruption of the outer nuclear layer (ONL). Preliminary ERG results showed a responsiveness of Rd1-Bmi1-/- mice in scotopic vision at P35. In conclusion, Bmi1 loss prevented, or rescued, photoreceptors from degeneration to an unanticipated extent in Rd1 mice. In this chapter, we will first provide a brief review of our work on the cortical NSCs and introduce the Bmi1 oncogene, thus offering a rational to our observations on the retina. [ABSTRACT FROM AUTHOR]

In western countries, retinitis pigmentosa (RP) affects 1/3,500 individuals and age related macula degeneration (AMD) affects 1% to 3% of the population aged over 60. In vitro generation of retinal cells is thus a promising tool to screen protective drugs and to provide an unlimited cell source for transplantation. However, one main limitation is the amount of cells available. Stem cells, that can generate unlimited quantity of cells, could overcome this hurdle. Indeed, stem cells are defined by three characteristics: the ability to produce a large population of cells (expansion) and the potency, to produce the differentiated cells composing the organ from which the stem cells are originated. They are also able to self-renew indefinitely: for instance haematopoietic stem cells, located in the bone marrow, can expand, divide and generate differentiated cells into the diverse lineages throughout the life, the stem cells conserving its status (Till et al, 1961). Intestinal stem cells also are able to regenerate the intestine all along life (Potten et al, 1975). The other stem cells properties are the ability to produce a large population of cells (expansion) and as well as the differentiated cells composing the organ from which they originated. [ABSTRACT FROM AUTHOR]

Leber congenital amaurosis (LCA) is a retinitis pigmentosa with early onset, leading to blindness in infants. There is currently no efficient therapy to treat LCA. At the present time, mutations in seven different genes have been associated with the disease (Hanein et al. 2004). In 10 to 15% of the cases LCA originates from a mutation in RPE65 (Gu et al. 1997), a gene specifically expressed in the cells of the retinal pigment epithelium layer (RPE cells). This gene encodes a 65kD protein the function of which has been dissected in a recently published study demonstrating its crucial role as a regulator of the visual cycle and a chaperone for the chromophore of the visual pigment (Xue et al. 2004). The patients affected by a mutation in this gene could benefit from a substitutive gene therapy consisting in the transfer of a fully functional allele of the RPE65 gene in RPE cells. Furthermore, animal models of RPE65 mutations have been identified (Aguirre et al. 1998; Veske et al. 1999) or genetically produced (Redmond et al. 1998) and thus provide the necessary tools to set up the conditions of such a strategy before a clinical trial can be started. The proof of feasibility of this approach has indeed already been established in dogs bearing a spontaneous mutation in the RPE65 gene (Acland et al. 2001; NarfstrÖm et al. 2003), as well as in knock-out mice (Dejneka et al. 2004; Lai et al. 2004). These studies have shown that an adeno-associated virus (AAV)-derived vector is able to deliver the RPE65 gene to RPE cells and thus to restore vision at least partially. Nevertheless, before a clinical trial can take place, a great effort must be provided to assess the bio-safety of the procedure. In particular, trans-gene expression has to be tightly controlled to achieve the following criteria: (i) expression should occur only in RPE cells; (ii) expression should reach the therapeutic level without disturbing the homeostasis of the target cells. [ABSTRACT FROM AUTHOR]