Genetically-modified human mesenchymal stem cells to express erythropoietin enhances differentiation into retinal photoreceptors: An in-vitro study

Dysfunctional or death of retinal photoreceptors is an irreversible phenomenon that is closely associated with a broad range of retinal degenerative diseases, such as retinitis pigmentosa and age-related macular degeneration (AMD), resulting in successive loss of visual function and blindness. In search for viable treatment for retinal degenerative diseases, mesenchymal stem cells (MSCs) has demonstrated promising therapeutic capabilities to repair and replace damaged photoreceptor cells in both in vitro and in vivo conditions. Nevertheless, the dearth of MSC differentiation capacity into photoreceptors has limited its use in cell replacement therapy. Erythropoietin (EPO) has vital role in early neural retinal cell differentiation and demonstrated rescue potential on dying photoreceptor cells. Hence, we aimed to evaluate the differentiation capacity of MSCs into photoreceptor cells in the presence of human EPO protein. We derived the MSC from human Wharton's jelly of umbilical cord and transduced the cells with lentivirus particles encoding EPO and green fluorescent protein (GFP) as reporter gene. The transduced cells were selectively cultured and induced to differentiate into photoreceptors by exposing to photoreceptor differentiation cocktail. Our preliminary results showed that transduced cells exposed to induction medium had an enhanced differentiation capacity when compared to non-transduced cells. Our results demonstrated a novel strategy to increase the yield of in vitro photoreceptor differentiation and may be potentially useful in improving the efficiency of stem cell transplantation for ocular disorders.

Assessment of different strategies for scalable production and proliferation of human myoblasts

OBJECTIVES

Myoblast transfer therapy (MTT) is a technique to replace muscle satellite cells with genetically repaired or healthy myoblasts, to treat muscular dystrophies. However, clinical trials with human myoblasts were ineffective, showing almost no benefit with MTT. One important obstacle is the rapid senescence of human myoblasts. The main purpose of our study was to compare the various methods for scalable generation of proliferative human myoblasts.

METHODS

We compared the immortalization of primary myoblasts with hTERT, cyclin D1 and CDK4^R24C , two chemically defined methods for deriving myoblasts from pluripotent human embryonic stem cells (hESCs), and introduction of viral MyoD into hESC-myoblasts.

RESULTS

Our results show that, while all the strategies above are suboptimal at generating bona fide human myoblasts that can both proliferate and differentiate robustly, chemically defined hESC-monolayer-myoblasts show the most promise in differentiation potential.

CONCLUSIONS

Further efforts to optimize the chemically defined differentiation of hESC-monolayer-myoblasts would be the most promising strategy for the scalable generation of human myoblasts, for applications in MTT and high-throughput drug screening.

Human Mesenchymal Stem Cells Expressing Erythropoietin Enhance Survivability of Retinal Neurons Against Oxidative Stress: An In Vitro Study

Retinal degeneration is a prominent feature in ocular disorders. In exploring possible treatments, Mesenchymal Stem Cells (MSCs) have been recognized to yield therapeutic role for retinal degenerative diseases. Studies have also displayed that erythropoietin (EPO) administration into degenerative retina models confers significant neuroprotective actions in limiting pathological cell death. In this study, we aimed to use MSCs to deliver EPO and to evaluate the ability of EPO to rescue retinal neurons from dying upon reactive oxidative stress induction. We derived human MSCs from Wharton's jelly (hWJMSCs) of the umbilical cord and cells were transduced with lentivirus particles encoding EPO and a reporter gene of green fluorescent protein (GFP). The supernatants of both transduced and non-transduced cells were collected and used as a pre-conditioning medium for Y79 retinoblastoma cells (retinal neuron cell line) following exposure to glutamate induction. Retinal cells exposed to glutamate showed reduced mitochondrial depolarization and enhanced improvement in cell viability when incubated with pre-conditioned media of transduced cells. Our results established a proof-of-concept that MSCs could be used as a candidate for the delivery of EPO therapeutic gene in the treatment of retinal degenerations.

Micro-Computed Tomography Detection of Gold Nanoparticle-Labelled Mesenchymal Stem Cells in the Rat Subretinal Layer

Mesenchymal stem cells are widely used in many pre-clinical and clinical settings. Despite advances in molecular technology; the migration and homing activities of these cells in in vivo systems are not well understood. Labelling mesenchymal stem cells with gold nanoparticles has no cytotoxic effect and may offer suitable indications for stem cell tracking. Here, we report a simple protocol to label mesenchymal stem cells using 80 nm gold nanoparticles. Once the cells and particles were incubated together for 24 h, the labelled products were injected into the rat subretinal layer. Micro-computed tomography was then conducted on the 15th and 30th day post-injection to track the movement of these cells, as visualized by an area of hyperdensity from the coronal section images of the rat head. In addition, we confirmed the cellular uptake of the gold nanoparticles by the mesenchymal stem cells using transmission electron microscopy. As opposed to other methods, the current protocol provides a simple, less labour-intensive and more efficient labelling mechanism for real-time cell tracking. Finally, we discuss the potential manipulations of gold nanoparticles in stem cells for cell replacement and cancer therapy in ocular disorders or diseases.