Therapeutic Extracellular Vesicles from Tonsil-Derived Mesenchymal Stem Cells for the Treatment of Retinal Degenerative Disease

BACKGROUND@#Retinal degenerative disease (RDD), one of the most common causes of blindness, is predominantly caused by the gradual death of retinal pigment epithelial cells (RPEs) and photoreceptors due to various causes. Cell-based therapies, such as stem cell implantation, have been developed for the treatment of RDD, but potential risks, including teratogenicity and immune reactions, have hampered their clinical application. Stem cell-derived extracellular vesicles (EVs) have recently emerged as a cell-free alternative therapeutic strategy; however, additional invasiveness and low yield of the stem cell extraction process is problematic. @*METHODS@#To overcome these limitations, we developed therapeutic EVs for the treatment of RDD which were extracted from tonsil-derived mesenchymal stem cells obtained from human tonsil tissue discarded as medical waste following tonsillectomy (T-MSC EVs). To verify the biocompatibility and cytoprotective effect of T-MSC EVs, we measured cell viability by co-culture with human RPE without or with toxic all-trans-retinal. To elucidate the cytoprotective mechanism of T-MSC EVs, we performed transcriptome sequencing using RNA extracted from RPEs. The in vivo protective effect of T-MSC EVs was evaluated using Pde6b gene knockout rats as an animal model of retinitis pigmentosa. @*RESULTS@#T-MSC EVs showed high biocompatibility and the human pigment epithelial cells were significantly protected in the presence of T-MSC EVs from the toxic effect of all-trans-retinal. In addition, T-MSC EVs showed a dosedependent cell death-delaying effect in real-time quantification of cell death. Transcriptome sequencing analysis revealed that the efficient ability of T-MSC EVs to regulate intracellular oxidative stress may be one of the reasons explaining their excellent cytoprotective effect. Additionally, intravitreally injected T-MSC EVs had an inhibitory effect on the destruction of the outer nuclear layer in the Pde6b gene knockout rat. @*CONCLUSIONS@#Together, the results of this study indicate the preventive and therapeutic effects of T-MSC EVs during the initiation and development of retinal degeneration, which may be a beneficial alternative for the treatment of RDD.

Intravitreal Dexamethasone Implant with Plasma Autoantibody Monitoring for Cancer-associated Retinopathy

No abstract available.

N102S Mutation of UBIAD1 Gene in a Family with Schnyder Crystalline Corneal Dystrophy

PURPOSE: Schnyder crystalline corneal dystrophy (SCCD) is an autosomal dominant disease characterized by progressive central corneal opacification and premature development of peripheral arcus in the cornea. This disease results from a point mutation of UBIAD1 in chromosome 1p34-36. Until now, 15 different mutations of UBIAD1 gene on chromosome 1p34-36 have been reported for Schnyder crystalline corneal dystrophy. More point mutations are expected to be added to the list in the future. Schnyder crystalline corneal dystrophy is a rare disease, with only three reported cases in Korea, although there has been no report of a genetically confirmed case of the disease. CASE SUMMARY: We encountered six patients with an N102S mutation of UBIAD1, who are from a family of two generation with 12 family members. Genetic confirmation for Schnyder crystalline corneal dystrophy was performed on these patients. This was the first report of a genetic confirmation of Schnyder crystalline corneal dystrophy in Korea. We will discuss our cases along with a review of the related literature.

Mechanism of Glomerular Basement Membrane Thickening in Human Membranous Nephropathy / 대한신장학회잡지

Membranous nephropathy is the most common cause of nephrotic syndrome in adult. To investigate the molecular mechanisms which underlie thickening of glomerular basement membrane, we analyzed alpha1(IV) collagen, alpha4(IV) collagen, laminin A, laminin B1, laminin B2, s-laminin, fibronectin, TGF-beta1 and TGF-beta2 mRNA expression in 21 renal biopsies with membranous nephropathy using in situ hybridization. In addition, 7 renal biopsies with no detectable abnormalities were used as control. In membranous nephropathy, the numbers of glomerular visceral epithelial cells expressing alpha1(IV) collagen, alpha4(IV) collagen, s-laminin and TGF-beta1 mRNA were significantly larger than in controls(p<0.05). Laminin A, laminin B1, laminin B2, fibronectin, and TGF-beta2 mRNA were rarely expressed in membranous nephropathy and in control group. The number of TGFbeta-1 mRNA expressing cells/glomerular cross-section correlated to that of alpha1(IV) collagen mRNA expressing cells (p< 0.05). These results indicate that increased presence of glomerular basement membrane proteins in spikes of membranous nephropathy is associated with enhanced mRNA expression of those proteins in the glomerular visceral epithelial cells. Subepithelial deposits in membranous nephropathy stimulate glomerular visceral epithelial cells to produce TGF-beta1, which in turn could mediate the expression of glomerular basement membrane protein genes by glomerular visceral epithelial cells.

Type IV Collagen mRNA Expression in Human Membranous Nephropathy

Human membranous nephropathy (MN) is morphologically characterized by subepithelial immune complex deposits and progressive thickening of glomerular basement membranes (GBM). Studies have suggested that the enhanced secretion of classical and novel type IV collagen chains in MN contributes to spike formation and the novel type IV collagen chain is particularly related to thickening of GBM. It is unclear whether the increased accumulation of extracellular matrix (ECM) proteins in GBM is due to the increased mRNA expression for type IV collagen in glomerular visceral epithelial cells (GECs). To answer this question, we analyzed seven renal biopsies of patients with idiopathic MN using in situ hybridization. In MN, the number of GECs expressing mRNA for alpha1(IV) collagen was 2.82+/-1.80/glomerular cross section (gcs), and the number expressing mRNA for alpha4(IV) collagen was 8.42+/-2.85/gcs. The number of GECs expressing mRNA for alpha4(IV) collagen was significantly larger than that of alpha1(IV) collagen mRNA. The expression of mRNA for these ECM proteins in normal controls was negligible. These results suggest that subepithelial immune complexes stimulate the gene expression of alpha1(IV) collagen and alpha4(IV) collagen in glomerular GECs which, in turn, increase the secretion of ECM proteins and contribute to the thickening of GBM in MN.