A spectral-domain optical coherence tomographic analysis of Rdh5-/- mice retina.

Purpose: To investigate the longitudinal findings of spectral-domain optical coherence tomography (SD-OCT) in relation to the morphologic features in Rdh5 knockout (Rdh5-/-) mice.

Materials And Methods: The mouse retina was segmented into four layers; the inner retinal (A), outer plexiform and outer nuclear (B), rod/cone (C), and retinal pigment epithelium (RPE)/choroid (D) layers. The thickness of each retinal layer of Rdh5-/- mice was longitudinally and quantitatively measured at six time points from postnatal months (PM) 1 to PM6 using SD-OCT.

Optical Coherence Tomography of Animal Models of Retinitis Pigmentosa: From Animal Studies to Clinical Applications.

Purpose: The aim of this study was to understand the relationship between the findings of spectral-domain optical coherence tomography (SD-OCT) of previously reported animal models of retinitis pigmentosa (RP) associated with known genetic mutations and their background structural and functional changes.

Methods: We reviewed previous publications reporting the SD-OCT findings of animal models of RP and summarized the characteristic findings of SD-OCT in nine different animal models ( , P23H, S334ter, , , rp12, (rd1 and rd10), and ) of human RP.

Results: Despite the various abnormal structural changes found in these different animal models, progressive thinning of the outer nuclear layer (ONL) and hyperreflective change in the inner and outer segment (IS-OS) layers of the photoreceptors were commonly observed on SD-OCT.

Characterization of photoreceptor degeneration in the rhodopsin P23H transgenic rat line 2 using optical coherence tomography.

Purpose: To characterize the optical coherence tomography (OCT) appearances of photoreceptor degeneration in the rhodopsin P23H transgenic rat (line 2) in relation to the histological, ultrastructural, and electroretinography (ERG) findings.

Materials And Methods: Homozygous rhodopsin P23H transgenic albino rats (line 2, very-slow degeneration model) were employed. Using OCT (Micron IV®; Phoenix Research Labs, Pleasanton, CA, USA), the natural course of photoreceptor degeneration was recorded from postnatal day (P) 15 to P 287.

The protection of rat retinal ganglion cells from ischemia/reperfusion injury by the inhibitory peptide of mitochondrial μ-calpain.

Intracellular Ca(2+)-dependent cysteine proteases such as calpains have been suggested as critical factors in retinal ganglion cell (RGC) death. However, it is unknown whether mitochondrial calpains are involved in RGC death. The purpose of the present study was to determine whether the inhibition of mitochondrial μ-calpain activity protects against RGC death during ischemia/reperfusion (I/R) injury.

Delivery of Topically Applied Calpain Inhibitory Peptide to the Posterior Segment of the Rat Eye.

We developed an inhibitory peptide that specifically acts against mitochondrial μ-calpain (Tat-μCL, 23 amino acid, 2857.37 Da) and protects photoreceptors in retinal dystrophic rats. In the present study, we topically administered Tat-μCL to the eyes of Sprague-Dawley rats for 7 days to determine both the delivery route of the peptide to the posterior segment of the eye and the kinetics after topical application in adult rats.

Light and electron microscopic studies of the intestinal epithelium in Notoplana humilis (Platyhelminthes, Polycladida): the contribution of mesodermal/gastrodermal neoblasts to intestinal regeneration.

Some free-living flatworms in the phylum Platyhelminthes possess strong regenerative capability that depends on putative pluripotent stem cells known as neoblasts. These neoblasts are defined based on several criteria, including their proliferative capacity and the presence of cellular components known as chromatoid bodies. Polyclads, which are marine flatworms, have the potential to be a good model system for stem cell research, yet little information is available regarding neoblasts and regeneration.

Protection of cone photoreceptor M-opsin degradation with 9-cis-β-carotene-rich alga Dunaliella bardawil in Rpe65(-/-) mouse retinal explant culture.

Purpose: RPE65, a retinal pigment epithelium-specific 65-kDa protein, plays a critical role in the visual cycle of the eye. Rpe65(-/-) mice develop vision loss due to a lack of 11-cis-retinal, degradation of M-opsin and mislocalization of S-opsin. Several studies have suggested that 9-cis-β-carotene, a precursor of 9-cis-retinal and all-trans-retinal, could have therapeutic applications in vision loss.

Decrease of ATP by mitochondrial m-calpain inhibitory peptide in the rat retinas.

Activations of mitochondrial calpains cause apoptosis-inducing factor-dependent apoptosis of retinal photoreceptor cells in the Royal College of Surgeons (RCS) rat, an animal model of retinitis pigmentosa. In the present study, we attempted to develop specific inhibitors of mitochondrial calpains that would prevent the retinal degeneration. We examined the inhibitory potency of 20-mer peptides of the m-calpain for mitochondrial calpains activity, determined the inhibitory regions, and conjugated the cell-penetrating peptides (CPP).

Inhibitory peptide of mitochondrial μ-calpain protects against photoreceptor degeneration in rhodopsin transgenic S334ter and P23H rats.

Mitochondrial μ-calpain and apoptosis-inducing factor (AIF)-dependent photoreceptor cell death has been seen in several rat and mouse models of retinitis pigmentosa (RP). Previously, we demonstrated that the specific peptide inhibitor of mitochondrial μ-calpain, Tat-µCL, protected against retinal degeneration following intravitreal injection or topical eye-drop application in Mertk gene-mutated Royal College of Surgeons rats, one of the animal models of RP. Because of the high rate of rhodopsin mutations in RP patients, the present study was performed to confirm the protective effects of Tat-µCL against retinal degeneration in rhodopsin transgenic S334ter and P23H rats.

Cisplatin binding and inactivation of mitochondrial glutamate oxaloacetate transaminase in cisplatin-induced rat nephrotoxicity.

Cisplatin is a widely used chemotherapeutic agent, but its use is limited by nephrotoxicity associated with mitochondrial dysfunction. Because its mechanisms are poorly understood, we aimed to identify the mitochondrial proteins targeted by cisplatin. We isolated renal mitochondrial proteins from Sprague-Dawley (SD) rats and performed cisplatin-affinity column chromatography.

Intravitreal injection or topical eye-drop application of a μ-calpain C2L domain peptide protects against photoreceptor cell death in Royal College of Surgeons' rats, a model of retinitis pigmentosa.

Mitochondrial μ-calpain initiates apoptosis-inducing factor (AIF)-dependent apoptosis in retinal photoreceptor degeneration. Mitochondrial μ-calpain inhibitors may represent therapeutic targets for the disease. Therefore, we sought to identify inhibitors of mitochondrial calpains and determine their effects in Royal College of Surgeons' (RCS) rats, an animal model of retinitis pigmentosa (RP).

M-opsin protein degradation is inhibited by MG-132 in Rpe65⁻/⁻ retinal explant culture.

Purpose: The 65 kDa retinal pigment epithelium-specific protein, RPE65, is an essential enzyme for 11-cis-retinal synthesis in the eye. Mutations of the RPE65 gene in humans result in severe vision loss, and Rpe65(-/-) mice show early cone photoreceptor degeneration. We used an explant culture system to evaluate whether posttranslational downregulation of M-opsin protein in Rpe65(-/-) mice is caused by proteolytic degradation.

Ca²+-induced release of mitochondrial m-calpain from outer membrane with binding of calpain small subunit and Grp75.

Although mitochondrial μ- and m-calpains play significant roles in apoptotic cell death, their activating mechanisms have not been determined. The purpose of this study was to determine the core factors that are involved in activating mitochondrial outer membrane (OM)-bound calpains. To accomplish this, we solubilized OM-bound calpains and separated them by DEAE-Sepharose column chromatography, and identified them by immunoblots.

Activation of mitochondrial calpain and release of apoptosis-inducing factor from mitochondria in RCS rat retinal degeneration.

The present study was performed to investigate changes of cytosolic and mitochondrial calpain activities, and effects of intravitreously injected calpain inhibitor on photoreceptor apoptosis in Royal College of Surgeon's (RCS) rats. Time courses of activities for both cytosolic and mitochondrial calpains and amount of calpastatin in RCS rat retina were analyzed by subcellular fractionation, calpain assay and western blotting. Calpain assay was colorimetrically performed using Suc-LLVY-Glo as substrate.

S-opsin protein is incompletely modified during N-glycan processing in Rpe65(-/-) mice.

Retinal pigment epithelium-specific protein 65 kDa (RPE65) is a key enzyme for the visual cycle in the eye. Rpe65(-/-) mice lack 11-cis-retinal, and show early cone degeneration and mislocalization of cone opsins. The present study investigated whether abnormal modification of cone opsins at the protein level is present in Rpe65(-/-) mice.

Mitochondrial m-calpain plays a role in the release of truncated apoptosis-inducing factor from the mitochondria.

Calpains, calcium-dependent cysteine proteases, are involved in a variety of cellular processes. We have reported on the characteristics of mitochondrial mu-calpain and have shown that ERp57-associated mitochondrial mu-calpain cleaves the apoptosis-inducing factor (AIF) to a truncated form (tAIF). In addition, we found an unknown mitochondrial calpain.

Antisense RNA inhibition of the beta subunit of the Dictyostelium discoideum mitochondrial processing peptidase induces the expression of mitochondrial proteins.

We cloned and characterized a cDNA encoding the Dictyostelium discoideum beta subunit of mitochondrial processing peptidase (Ddbeta-MPP). Western blot analysis of the mitochondrial subfractions revealed that Ddbeta-MPP is located in the mitochondrial matrix and membrane, whereas Dd(alpha)-MPP, another subunit of DdMPP, is located only in the matrix. Although expression of Ddbeta-MPP mRNA is down-regulated during early development, the level of the Ddbeta-MPP protein is constant throughout the Dictyostelium life cycle.

ERp57-associated mitochondrial μ-calpain truncates apoptosis-inducing factor.

Calpains, calcium-dependent neutral cystein proteases, are involved in a variety of cellular processes. We have previously shown the characteristics of mitochondrial micro-calpain even though calpastatin, a specific endogenous inhibitor of cytosolic calpains, was not present in the mitochondria. This suggested that the regulatory system of mitochondrial calpains differs from that of cytosolic calpains, and endogenous regulatory molecule(s) must exist in the mitochondria.

BDNF increases the phagocytic activity in cultured iris pigment epithelial cells.

To investigate the effect of brain derived neurotrophic factor (BDNF) on the phagocytic activity in iris pigment epithelial (IPE) cells, purified porcine photoreceptor outer segments (POS) were applied to cultured IPE cells for three hours. To measure phagocytic activities, bound and total POS were differentially stained using a double immunofluorescence staining method. BDNF increased the binding of POS in IPE cells in a dose-dependent manner.

Characteristics of mitochondrial calpains.

Calpains are considered to be cytoplasmic enzymes, although several studies have shown that calpain-like protease activities also exist in mitochondria. We partially purified mitochondrial calpain from swine liver mitochondria and characterized. Only one type of mitochondrial calpain was detected by the column chromatographies.

Temporal and spatial differences in expression of TrkB isoforms in rat retina during constant light exposure.

Brain-derived neurotrophic factor (BDNF) has been reported to rescue neuroretinal cells under different toxic conditions. These cells include not only those expressing BDNF receptors (TrkB) but also those not expressing TrkB including photoreceptors. The purpose of this study was to determine the retinal sites at which BDNF and TrkB isoforms are expressed after different durations of continuous light exposure, and to compare these sites with those of TUNEL-positive cells in the same retina.

Nitric oxide-induced accumulation of lipofuscin-like materials is caused by inhibition of cathepsin S.

To determine whether nitric oxide (NO) is involved in accumulation of lipofuscin-like material (LFM) in retinal pigment epithelial (RPE) cells and if this formation is related to NO-mediated modification of cathepsin S (cat S). RPE cell cultures were fed once every day with porcine photoreceptor outer segments (POS) in the presence of NO-donor [S-nitroso-N-acetylpenicillamine (SNAP) or NOC18] for 2 weeks. LFM autofluorescence within the cells was measured by fluorophotometric flow cytometry (FACS).

Establishment of effective methods for transducing genes into iris pigment epithelial cells by using adeno-associated virus type 2.

Purpose: To establish an efficient method of transferring the human brain-derived neurotrophic-factor (hBDNF) gene into human iris pigment epithelial (hIPE) cells by using recombinant adeno-associated virus type 2 (rAAV2).

Methods: Cultured hIPE cells were treated with either hydroxyurea-sodium butyrate (HUSB; DNA synthesis inhibitor), or tyrphostin-1 (Tyr; epidermal growth factor receptor [EGFR] tyrosine kinase inhibitor), or a combination of HUSB and Tyr (HUSB-Tyr). After each treatment, cells were exposed to rAAV2 (rAAV-LacZ or rAAV-hBDNF).