The transplantation of mesenchymal stem cells (MSCs) is considered to be a promising treatment for ischemic heart disease; however, the therapeutic effects and underlying mechanisms of action require further evaluation. Mitochondrial dysfunction is a key event in simulated ischemia/reperfusion (SI/R) injury. The purpose of the present study was to investigate the mechanism of mitochondrial transfer, which may be involved the antiapoptotic action of co-culture with MSCs. An in vitro model of simulated ischemia/reperfusion (SI/R) was used in the present study. The apoptotic indexes were significantly increased when H9c2 cardiomyocytes were induced in the SI/R group. Following co-culture with bone marrow-derived (BM)-MSCs, H9c2 cells exhibited marked resistance against the SI/R-induced apoptotic process. Besides, mitochondrial transfer via a tunneling nanotube (TNT) like structure was detected by confocal fluorescent microscopy. In addition, following pretreated with latrunculin-A (LatA), an inhibitor of TNT formation, the BM-MSCs were not able to rescue injured H9c2 cells from apoptosis, as previously observed. In conclusion, the anti-apoptotic ability of BM-MSCs may be partially attributed to the recovery of mitochondrial dysfunction in SI/R, and the formation of TNTs appears to be involved in this action of mitochondrial transfer between adjacent cells.

Islet replacement therapy is limited by shortage of donor islet cells. Usage of islet cells derived from porcine pancreatic stem cells (PSCs) is currently viewed as the most promising alternative for human islet transplantation. However, PSCs are rare and have a finite proliferative lifespan. In this study, we isolated and established an immortalized mesenchymal stem cell (MSC) line derived from foetal porcine pancreas, by transfecting human telomerase reverse transcriptase (hTERT) and called these immortalized pancreatic mesenchymal stem cells (iPMSCs). The iPMSCs have been cultured for more than 80 passages and have capacity to differentiate into neurons, cardiomyocytes, germ cells and islet-like cells, analysed by morphology, RT-PCR, western blotting, immunofluorescence, immunocytochemistry and transplantation assay. Islets derived from iPMSCs reversed hyperglycaemia in streptozotocin-induced diabetic mice and secreted insulin and C-peptide in vitro. These results demonstrated that iPMSCs might provide unlimited resources for islet replacement therapy and models for functional cell differentiation.

Citation: Huang P, Sun J, Wang F, et al. MicroRNA expression patterns involved in amyloid beta-induced retinal degeneration. Invest Ophthalmol Vis Sci. 2017;58:172658: -173558: . DOI: 10.1167 PURPOSE. Dry age-related macular degeneration (AMD) is characterized by the accumulation of drusen under Bruch's membrane, and amyloid beta (Ab) is speculated to be one of the key pathologic factors. While the detrimental effects of Ab on retinas have been widely explored, Ab-induced epigenetic regulatory changes have yet to be fully investigated. We therefore aimed to identify the microRNA (miRNA) expression profiles in an Ab-induced mouse model of retinal degeneration.METHODS. C57BL/6 mice were intravitreally injected with Ab 1-40 or PBS and the eye tissues were collected for hematoxylin and eosin (H&E) staining, apoptosis immunofluorescence staining, and miRNA profiling. After filtering, 10 miRNAs and their target genes were chosen for quantitative RT-PCR (qRT-PCR) confirmations. Pathway analyses were employed for further bioinformatic analyses.RESULTS. Hematoxylin and eosin-stained sections of retinal pigment epithelium (RPE)/neural retina tissue demonstrated degenerative alterations, and immunofluorescence testing revealed apoptosis within the retina after Ab treatments. MicroRNA profiling revealed 61 miRNAs that were differentially expressed between the model and the control group. Among these, 38 miRNAs were upregulated (fold change > 1.5, P < 0.05) and 23 miRNAs were downregulated (fold change < 0.667, P < 0.05). Five of the 10 selected miRNAs (miR-142, miR-216, miR-155, miR-223, and miR-433) as well as several key target genes (CFH, IGF-1R, c-MET, and ABCA1) were confirmed by qRT-PCR analyses.CONCLUSIONS. Our study is the first to profile the miRNA expression patterns and suggests that Ab accumulation could lead to relevant biochemical alternations such as complement activation, barrier impairment, apoptosis, and positive feedback of Ab production.

Subretinal fibrosis results in local destruction of retinal structures and permanent vision loss, representing the end stage of neovascular age-related macular degeneration (AMD). Histological examination of fibrotic specimens from AMD patients has uncovered a wide range of cellular and acellular components. However, their origins and roles in fibrosis remain largely unexplored. Using a laser-induced photocoagulation model with collagen 1α1-GFP reporter mice, we demonstrate, by cell-lineage tracing, that pericytes associating with choroidal microvasculature are activated upon injury and infiltrate into the subretinal space as significant components of fibrotic lesions. In contrast to their choroidal precursors, infiltrating pericytes acquire stellate-like structures, upregulate expression of fibrogenic molecules and colocalize with extracellular fibrotic scar. Collectively, our results identify the choroidal perivascular niche as a novel source of subretinal fibrosis after photocoagulation, and suggest that collagen 1-expressing pericytes are potential targets for therapeutic intervention to suppress subretinal fibrosis and preserve vision.