Differentiation and neuro-protective properties of immortalized human tooth germ stem cells.

Stem cells are considered to be promising therapeutic options in many neuro-degenerative diseases and injuries to the central nervous system, including brain ischemia and spinal cord trauma. Apart from the gold standard embryonic and mesenchymal origin, human tooth germ stem cells (hTGSCs) have also been shown to enjoy the characteristics of mesenchymal stem cells (MSCs) and the ability to differentiate into adipo-, chondro-, osteo- and neuro-genic cells, suggesting that they might serve as potential alternatives in the cellular therapy of various maladies. Immortalization of stem cells may be useful to avoid senescence of stem cells and to increase their proliferation potential without altering their natural characteristics. This study evaluated the expression of stem cell markers, surface antigens, differentiation capacity, and karyotype of hTGSCs that have been immortalized by human telomerase reverse transcriptase (hTERT) or simian vacuolating virus 40 (SV40) large T antigen. These undying cells were also evaluated for their neuro-protective potential using an in vitro SH-SY5Y neuro-blastoma model treated with hydrogen-peroxide or doxo-rubicin. Although hTGSC-SV40 showed abnormal karyotypes, our results suggest that hTGSC-hTERT preserve their MSC characteristics, differentiation capacity and normal karyotype, and they also possess high proliferation rate and neuro-protective effects even at great passage numbers. These peculiars indicate that hTGSC-hTERT could be used as a viable model for studying adipo-, osteo-, odonto- and neuro-genesis, as well as neuro-protection of MSCs, which may serve as a springboard for potentially utilizing dental waste material in cellular therapy.

Impact of Autoimmune Demyelinating Brain Disease Sera on Pericyte Survival.

INTRODUCTION: Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) characterized by demyelination and brain pericyte dysfunction might be involved in MS pathogenesis Our aim was to evaluate whether the factors in serum affect pericyte survival. METHOD: C57BL/6 female mice were immunized with myelin oligodendrocyte glycoprotein (MOG) to induce experimental autoimmune encephalomyelitis (EAE). To confirm the animal model, the sera level of anti-MOG antibody in mice and platelet-derived growth factor-BB (PDGF-BB) in patients was measured by ELISA. Human brain vascular pericytes (HBVP) cell lines were incubated with sera of EAE mice and primer progressive MS (PPMS), seconder progressive MS (SPMS) and relapsing-remitting MS (RRMS) patients. The viability of HBVP is measured with Annexin V-FITC/propidium iodide staining with flow cytometry. RESULTS: Annexin V-FITC/propidium iodide staining with flow cytometry showed increased ratios of early apoptosis and decreased survival following incubation with sera of EAE and progressive MS. Levels of platelet-derived growth factor-BB were identical in serum and cerebrospinal fluids of patients with different forms of MS. CONCLUSION: Our results suggest that serum factors might contribute to progressive MS pathogenesis via pericyte dysfunction.

Suppressor Effects of Sodium Pentaborate Pentahydrate and Pluronic F68 on Adipogenic Differentiation and Fat Accumulation.

Obesity is a major public health problem worldwide and a risk factor for certain diseases, including cardiovascular disease, diabetes, cancer, and depression. Unfortunately, currently available anti-obesity drugs have failed in the long-term maintenance of weight control. It has been a challenge to design novel drugs that could potentially treat obesity or prevent uncontrolled weight-gain which lies underneath the pathology of obesity. Since obesity in a way is a consequence of the accumulating new mature adipocytes from undifferentiated precursors which is a process also termed as adipogenesis, drugs that might control adipogenesis could be beneficial for the treatment of obesity. In the current study, combined effect of sodium pentaborate pentahydrate (NaB) and pluronic F68 on adipogenic differentiation was examined by administering various combinations of the two agents to human adipose-derived stem cells (hADSCs) in in vitro. Immunocytochemistry and quantitative RT-PCR were performed to evaluate the levels of adipogenesis-promoting genes such as peroxisome proliferator-activated receptor-γ (PPARγ), fatty acid binding protein (FABP4), and adiponectin. Results indicated that expressions of all these three genes were restrained. Furthermore, Oil Red O staining revealed that lipid vesicle formation was reduced in hADSCs treated with differentiation medium containing NaB/F68 combination. Finally, expression levels of Hippo pathway kinases Lats2, MST1, and scaffold protein Sav1 were reduced in these cells, suggesting a possible link between Hippo pathway-dependent downregulation of PPARγ and the NaB/F68 treatment. Herein, we showed that combination of NaB and F68 curtails adipocyte differentiation by inhibiting the adipogenic transcriptional program leading to a decrease in lipid accumulation in adipocytes even at very low doses, thereby uncovered a striking opportunity to use this combination in obesity treatment.

Effect of F68 on cryopreservation of mesenchymal stem cells derived from human tooth germ.

The use of stem-cell-based therapies in regenerative medicine and in the treatment of disorders such as Parkinson, Alzheimer's disease, diabetes, spinal cord injuries, and cancer has been shown to be promising. Among all stem cells, mesenchymal stem cells (MSCs) were reported to have anti-apoptotic, immunomodulatory, and angiogenic effects which are attributed to the restorative capacity of these cells. Human tooth germ stem cells (HTGSCs) having mesenchymal stem cell characteristics have been proven to exert high proliferation and differentiation capacity. Unlike bone-marrow-derived MSCs, HTGSCs can be easily isolated, expanded, and cryopreserved, which makes them an alternative stem cell source. Regardless of their sources, the stem cells are exposed to physical and chemical stresses during cryopreservation, hindering their therapeutic capacity. Amelioration of the side effects of cryopreservation on MSCs seems to be a priority in order to maximize the therapeutic efficacy of these cells. In this study, we tested the effect of Pluronic 188 (F68) on HTGSCs during long-term cryopreservation and repeated freezing and defrosting cycles. Our data revealed that F68 has a protective role on survival and differentiation of HTGSCs in long-term cryopreservation.