Expression of immature and mature retinal cell markers in retinoblastoma

Tumor Environment of Retinoblastoma, Intraocular Cancer

Retinoblastoma, an intraocular cancer primarily affecting children, interacts with surrounding intraocular and extraocular structures in the development and progression. Subretinal and vitreous seeds are characteristic features of retinoblastoma, which result from the interaction between the tumor and its environment at the levels of tissue and microenvironment. The retina and vitreous affect the disease course and responses to treatment options. Also, neighboring cells in the retina and physicochemical properties of the tumor microenvironment are related to the biological activities of retinoblastoma tumors. Researches focusing on the tumor environment of retinoblastoma will lead to the development of more effective treatment options, which can revolutionize the prognosis of patients with retinoblastoma.

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.

ASSOCIATION BETWEEN AQUEOUS HUMOR CXC MOTIF CHEMOKINE LIGAND 13 LEVELS AND SUBFOVEAL CHOROIDAL THICKNESS IN NORMAL OLDER SUBJECTS

PURPOSE

To investigate the association of subfoveal choroidal thickness with intraocular inflammatory cytokines and chemokines.

METHODS

The subjects consisted of 76 eyes of consecutive cataract patients at the Japan Community Health Care Organization Tokyo Shinjuku Medical Center between September 2010 and August 2012. In addition, two autopsy eyes from elderly males were used for immunohistochemical study. Subfoveal choroidal thickness was measured using spectral domain optical coherence tomography before cataract surgery. At the beginning of cataract surgery, a sample of undiluted aqueous humor was manually aspirated and the concentrations of the following cytokines were determined using a multiplex cytokine assay: IP-10, MCP-1, MMP-9, IL-6, IL-10, CXCL1, CXCL12, CXCL13, and CCL11. The association of subfoveal choroidal thickness with intraocular cytokine concentration was analyzed. Expression of CXCL13 was examined in autopsy eyes.

RESULTS

Among these factors, higher concentration of CXCL13 was associated with thicker choroid. In particular, multiple regression analysis showed that the concentration of CXCL13 was associated with subfoveal choroidal thickness (P = 0.001), independently of axial length (P = 0.049). By immunostaining, CXCL13 was clearly detected in choroidal endothelial cells.

CONCLUSION

Aqueous humor concentration of CXCL13 is correlated with subfoveal choroidal thickness in normal subjects.

Embryonic retinal tumors in SV40 T-Ag transgenic mice contain CD133+ tumor-initiating cells

PURPOSE

Human retinoblastomas form during the proliferative phase of retina development and are caused by mutations that result in absent or functionally defective Rb protein. Similar tumors occur in mice only when multiple Rb gene family members are absent. We asked if retinal tumors can arise from an undifferentiated retinal cell. The tumor-initiating cells isolated from these tumors that formed in early embryonic murine retinas were characterized.

METHODS

Transgenic mice were created using a Pax6 promoter to target expression of SV40 large T-antigen (T-Ag) in the undifferentiated murine embryonic retina. T-Ag, which sequesters all Rb family proteins and p53, is expressed in the retina and lens by murine embryonic day 10 (E10) and tumors are observed by E12.5. A cell line that is adherent in serum-containing media and forms neurospheres in supplemented serum-free media was developed from retinal tumors isolated on postnatal day 7.

RESULTS

In all, 1.5% of attached cells form neurospheres when transferred to serum-free medium. All cultured cells express T-Ag, confirming that they derive from the original tumors; 0.5% of adherent cells express detectable levels of CD133. CD133+ FACS-sorted cells cultured in serum-free medium form 3-fold more neurospheres than do CD133- cells. Six of seven mice injected with CD133+ cells and one of seven mice injected with CD133- cells formed tumors during a 6-month period. Unlike primary adherent cells, primary and secondary tumors heterogeneously express markers of stem cells and differentiation similar to human retinoblastoma.

CONCLUSIONS

CD133+ tumor-initiating cells can originate from proliferating undifferentiated precursor cells.

Differentiation of human bone marrow mesenchymal stem cells into neuron-like cells in vitro

STUDY DESIGN

Responses of human mesenchymal stem cells from bone marrow (hBMSCs) were analyzed under chemical conditions, and then characterization of ion channels was evaluated by whole-cell patch clamp.

OBJECTIVE

To explore the possibility of differentiation of human bone marrow-derived mesenchymal stem cells into neuron-like cells in vitro under different conditions.

SUMMARY OF BACKGROUND DATA

The generation of mesenchymal stem cells into neuron-like cells has been studied. However, few of these studies characterized functional properties of the differentiated hBMSCs.

METHODS

hBMSCs (Passage 2) were expanded and cultured in vitro. After Passage 5 was subcultured, the cells were induced by cytokines and antioxidants. Morphologic observation, immunocytochemistry, Western blot analysis, and patch-clamp techniques were performed to evaluate properties of treated and control groups.

RESULTS

The differentiated neuronal cells from hBMSCs not only expressed neuron phenotype and membrane channel protein including Nav1.6, Kv1.2, Kv1.3, and Cav1.2 but also exhibited functional ion currents. Both hBMSCs and differentiated cells expressed Nav1.6, Kv1.2, Kv1.3, and Cav1.2 and voltage-activated potassium currents, including delayed rectifier, noise-like and transient outward currents. However, expression of channel proteins, such as sodium channel Nav1.6 and potassium channels Kv1.2 and Kv1.3, were upregulated. Consistently, their potassium currents were also enhanced in the differentiated cells.

CONCLUSION

hBMSCs possess of great potential to differentiate into functional neurons, indicating that hBMSCs may be an ideal cell source in managing a variety of clinical diseases such as spinal cord injury.