Biomedical subjects

Corinne Kostic

Publications and source records attributed to Corinne Kostic.

5 recordsLinked to original sources

PubMed2006

High yield of cells committed to the photoreceptor fate from expanded mouse retinal stem cells.

The purpose of the present work was to generate, from retinal stem cells (RSCs), a large number of cells committed toward the photoreceptor fate in order to provide an unlimited cell source for neurogenesis and transplantation studies. We expanded RSCs (at least 34 passages) sharing characteristics of radial glial cells and primed the cells in vitro with fibroblast growth factor (FGF)-2 for 5 days, after which cells were treated with the B27 supplement to induce cell differentiation and maturation. Upon differentiation, cells expressed cell type-specific markers corresponding to neurons and glia. We show by immunocytochemistry analysis that a subpopulation of differentiated cells was committed to the photoreceptor lineage given that these cells expressed the photoreceptor proteins recoverin, peripherin, and rhodopsin in a same ratio. Furthermore, cells infected during the differentiation procedure with a lentiviral vector expressing green fluorescent protein (GFP) under the control of either the rhodopsin promoter or the interphotoreceptor retinoid-binding protein (IRBP) promoter, expressed GFP. FGF-2 priming increased neuronal differentiation while decreasing glia generation. Reverse transcription-polymerase chain reaction analyses revealed that the differentiated cells expressed photoreceptor-specific genes such as Crx, rhodopsin, peripherin, IRBP, and phosphodiesterase-alpha. Quantification of the differentiated cells showed a robust differentiation into the photoreceptor lineage: Approximately 25%-35% of the total cells harbored photoreceptor markers. The generation of a significant number of nondifferentiated RSCs as well as differentiated photoreceptors will enable researchers to determine via transplantation studies which cells are the most adequate to integrate a degenerating retina.

Animals↗

PubMed2006

Lentiviral gene transfer of RPE65 rescues survival and function of cones in a mouse model of Leber congenital amaurosis.

BACKGROUND: RPE65 is specifically expressed in the retinal pigment epithelium and is essential for the recycling of 11-cis-retinal, the chromophore of rod and cone opsins. In humans, mutations in RPE65 lead to Leber congenital amaurosis or early-onset retinal dystrophy, a severe form of retinitis pigmentosa. The proof of feasibility of gene therapy for RPE65 deficiency has already been established in a dog model of Leber congenital amaurosis, but rescue of the cone function, although crucial for human high-acuity vision, has never been strictly proven. In Rpe65 knockout mice, photoreceptors show a drastically reduced light sensitivity and are subject to degeneration, the cone photoreceptors being lost at early stages of the disease. In the present study, we address the question of whether application of a lentiviral vector expressing the Rpe65 mouse cDNA prevents cone degeneration and restores cone function in Rpe65 knockout mice. METHODS AND FINDINGS: Subretinal injection of the vector in Rpe65-deficient mice led to sustained expression of Rpe65 in the retinal pigment epithelium. Electroretinogram recordings showed that Rpe65 gene transfer restored retinal function to a near-normal pattern. We performed histological analyses using cone-specific markers and demonstrated that Rpe65 gene transfer completely prevented cone degeneration until at least four months, an age at which almost all cones have degenerated in the untreated Rpe65-deficient mouse. We established an algorithm that allows prediction of the cone-rescue area as a function of transgene expression, which should be a useful tool for future clinical trials. Finally, in mice deficient for both RPE65 and rod transducin, Rpe65 gene transfer restored cone function when applied at an early stage of the disease. CONCLUSIONS: By demonstrating that lentivirus-mediated Rpe65 gene transfer protects and restores the function of cones in the Rpe65(-/-) mouse, this study reinforces the therapeutic value of gene therapy for RPE65 deficiencies, suggests a cone-preserving treatment for the retina, and evaluates a potentially effective viral vector for this purpose.

Animals↗

PubMed2005

Bmi1 loss produces an increase in astroglial cells and a decrease in neural stem cell population and proliferation.

The polycomb transcriptional repressor Bmi1 promotes cell cycle progression, controls cell senescence, and is implicated in brain development. Loss of Bmi1 leads to a decreased brain size and causes progressive ataxia and epilepsy. Recently, Bmi1 was shown to control neural stem cell (NSC) renewal. However, the effect of Bmi1 loss on neural cell fate in vivo and the question whether the action of Bmi1 was intrinsic to the NSCs remained to be investigated. Here, we show that Bmi1 is expressed in the germinal zone in vivo and in NSCs as well as in progenitors proliferating in vitro, but not in differentiated cells. Loss of Bmi1 led to a decrease in proliferation in zones known to contain progenitors: the newborn cortex and the newborn and adult subventricular zone. This decrease was accentuated in vitro, where we observed a drastic reduction in NSC proliferation and renewal because of NSC-intrinsic effects of Bmi1 as shown by the means of RNA interference. Bmi1(-/-) mice also presented more astrocytes at birth, and a generalized gliosis at postnatal day 30. At both stages, colocalization of bromodeoxyuridine and GFAP demonstrated that Bmi1 loss did not prevent astrocyte precursor proliferation. Supporting these observations, Bmi1(-/-) neurospheres generate preferentially astrocytes probably attributable to a different responsiveness to environmental factors. Bmi1 is therefore necessary for NSC renewal in a cell-intrinsic mode, whereas the altered cell pattern of the Bmi1(-/-) brain shows that in vivo astrocyte precursors can proliferate in the absence of Bmi1.

Animals↗

PubMed2003

Delivery of ciliary neurotrophic factor via lentiviral-mediated transfer protects axotomized retinal ganglion cells for an extended period of time.

Ciliary neurotrophic factor (CNTF) has recently been demonstrated to be one of the most promising neurotrophic factors to improve both the survival and regeneration of injured retinal ganglion cells (RGCs). In the present study, we used optic nerve transection as an in vivo model to evaluate the effectiveness of a self-inactivating, replication-deficient lentiviral-mediated transfer of human ciliary neurotrophic factor (SIN-PGK-CNTF) on the survival of axotomized adult rat RGCs. Counts of dextran-fluorescein isothiocyanate conjugated (D-FITC)-retrogradely labeled RGCs revealed that the percentage of RGCs was drastically reduced (<90% cell death) 21 days after optic nerve transection. Retinal sections stained with X-gal revealed that intravitreal injection of the control LacZ-expressing lentiviral vector (LV-LacZ) resulted in the transduction of RGCs and retinal pigment epithelium (RPE) cells. A single intravitreal injection of LV-CNTF at the time of axotomy significantly enhanced RGC survival at 14 and 21 days postaxotomy compared to controls. These results demonstrate for the first time that rapid and prolonged delivery of CNTF using lentiviral-mediated gene transfer to the retina is an effective treatment for rescuing axotomized RGCs for an extended period of time. These results suggest that early and continuous administration of CNTF could serve as a potential treatment for retinal disorders involving optic neuropathy and RGC injury such as in glaucoma.

Animals↗

PubMed2003

Non-neural regions of the adult human eye: a potential source of neurons?

PURPOSE: Because it is known that both melanocytes and neurons are generated from neural crest stem cells and their derived precursors, the current study was undertaken to evaluate whether adult human ocular tissues, containing melanocytes, have the capacity to generate neuronlike cells in vitro. METHODS: Choroid and Sclera cells from adult human eyes were separately dissociated and cultivated in the presence of epidermal growth factor and 10% fetal bovine serum. No retinal pigmented epithelial cells were detected. After cell growth, cells were transferred under conditions known to induce neuronal differentiation. Cells were plated on laminin in the presence of fibroblast growth factor-2 or brain-derived neurotrophic factor. RESULTS: Cells derived from the sclera and the choroid of 15 donors proliferated to attain a 10(8)-fold increase in the number of cells within 4 months. At each passage, groups of cells differentiated into cells with neuronal morphology, expressing neuronal markers confirmed by immunocytochemistry and RT-PCR analyses, such as beta-tubulin-III, neurofilament, and tau. Parallel to neuronlike formation, glialike cells, revealed by expression of vimentin and P0, were generated in large amounts. Although, absent from choroid and sclera tissues, nondifferentiated cells appeared in cultures. CONCLUSIONS: The adult human eye conserves cells able to recapitulate certain neural developmental features. This observation opens new perspectives to study human neurogenesis and to provide an important source of neurons for transplantation studies in the retina and other regions of the central nervous system.

Adolescent↗