Embryonic stem cell-derived photoreceptor precursor cells differentiated by coculture with RPE cells.

Purpose: To describe the derivation of photoreceptor precursor cells from human embryonic stem cells by coculture with RPE cells. Methods: Human embryonic stem cells were induced to differentiate into neural precursor cells and then cocultured with RPE cells to obtain cells showing retinal photoreceptor features. Immunofluorescent staining, reverse transcription-PCR (RT-PCR), and microarray analysis were performed to identify photoreceptor markers, and a cGMP assay was used for in vitro functional analysis. After subretinal injection in rat animal models, retinal function was determined with electroretinography and optokinetic response detection, and immunofluorescent staining was performed to assess the survival of the injected cells. Results: Cocultured cells were positive for rhodopsin, red and blue opsin, recoverin, and phosphodiesterase 6 beta on immunofluorescent staining and RT-PCR. Serial detection of stem cell-, neural precursor-, and photoreceptor-specific markers was noted in each stage of differentiation with microarray analysis. Increased cGMP hydrolysis in light-exposed conditions compared to that in dark conditions was observed. After the subretinal injection in the rats, preservation of optokinetic responses was noted up to 20 weeks, while electroretinographic response decreased. Survival of the injected cells was confirmed with positive immunofluorescence staining of human markers at 8 weeks. Conclusions: Cells showed photoreceptor-specific features when stem cell-derived neurogenic precursors were cocultured with RPE cells.

Targeted Delivery of Iron Oxide Nanoparticle-Loaded Human Embryonic Stem Cell-Derived Spherical Neural Masses for Treating Intracerebral Hemorrhage.

This study evaluated the potential of iron oxide nanoparticle-loaded human embryonic stem cell (ESC)-derived spherical neural masses (SNMs) to improve the transportation of stem cells to the brain, ameliorate brain damage from intracerebral hemorrhage (ICH), and recover the functional status after ICH under an external magnetic field of a magnet attached to a helmet. At 24 h after induction of ICH, rats were randomly separated into three experimental groups: ICH with injection of phosphate-buffered saline (PBS group), ICH with intravenous injection of magnetosome-like ferrimagnetic iron oxide nanocubes (FION)-labeled SNMs (SNMs* group), and ICH with intravenous injection of FION-labeled SNMs followed by three days of external magnetic field exposure for targeted delivery by a magnet-embedded helmet (SNMs*+Helmet group). On day 3 after ICH induction, an increased Prussian blue-stained area and decreased swelling volume were observed in the SNMs*+Helmet group compared with that of the other groups. A significantly decreased recruitment of macrophages and neutrophils and a downregulation of pro-inflammatory cytokines followed by improved neurological function three days after ICH were observed in the SNMs*+Helmet group. Hemispheric atrophy at six weeks after ICH was significantly decreased in the SNMs*+Helmet group compared with that of the PBS group. In conclusion, we have developed a targeted delivery system using FION tagged to stem cells and a magnet-embedded helmet. The targeted delivery of SNMs might have the potential for developing novel therapeutic strategies for ICH.

Magnetic Iron Oxide Nanoparticle Labeling of Photoreceptor Precursors for Magnetic Resonance Imaging.

IMPACT STATEMENT: This study describes the methods and results of superparamagnetic iron oxide nanoparticle (SPION) labeling and magnetic resonance imaging (MRI) tracking of human embryonic stem cell-derived photoreceptor precursors transplanted into the subretinal space of Royal College of Surgeons rats. SPION labeling and MRI tracking provide information about the biodistribution of transplanted photoreceptor precursors, which is necessary for improving the functional benefits of cell therapy for degenerative retinal diseases.

Hybrid Nanofiber Scaffold-Based Direct Conversion of Neural Precursor Cells/Dopamine Neurons.

The concept of cellular reprogramming was developed to generate induced neural precursor cells (iNPCs)/dopaminergic (iDA) neurons using diverse approaches. Here, we investigated the effects of various nanoscale scaffolds (fiber, dot, and line) on iNPC/iDA differentiation by direct reprogramming. The generation and maturation of iDA neurons (microtubule-associated protein 2-positive and tyrosine hydroxylase-positive) and iNPCs (NESTIN-positive and SOX2-positive) increased on fiber and dot scaffolds as compared to that of the flat (control) scaffold. This study demonstrates that nanotopographical environments are suitable for direct differentiation methods and may improve the differentiation efficiency.

Effects of short-term exposure to sevoflurane on the survival, proliferation, apoptosis, and differentiation of neural precursor cells derived from human embryonic stem cells.

PURPOSE: Data from animal experiments suggest that exposure to general anesthetics in early life inhibits neurogenesis and causes long-term memory deficit. Considering short operating times and the popularity of sevoflurane in pediatric anesthesia, it is important to verify the effects of short-period exposure to sevoflurane on the developing brain. METHODS: We measured the effects of short-term exposure (2 h) to 3%, 6%, or 8% sevoflurane, the most commonly used anesthetic, on neural precursor cells derived from human embryonic stem cells, SNUhES32. Cell survival, proliferation, apoptosis, and differentiation on days 1, 3, 5, and 7 post treatment were analyzed. RESULTS: Treatment with 6% sevoflurane increased cell viability (P = 0.046) and decreased apoptosis (P = 0.014) on day 5, but the effect did not persist on day 7. Survival and apoptosis were not affected by 3% and 8% sevoflurane; there was no effect of proliferation at any of the tested concentrations. The differentiation of cells exposed to 6% or 8% sevoflurane decreased on day 1 (P = 0.033 and P = 0.036 for 6% and 8% sevoflurane, respectively) but was again normalized on days 3-7. CONCLUSION: Clinically relevant treatment with sevoflurane for 2 h induces no significant changes in the survival, proliferation, apoptosis, and differentiation of human neural precursor cells, although supraclinical doses of sevoflurane do alter human neurogenesis transiently.

Reproducible Motor Deficit Following Aortic Occlusion in a Rat Model Of Spinal Cord Ischemia.

Spinal cord ischemia is a fatal complication following thoracoabdominal aortic aneurysm surgery. Researchers can investigate the strategies for preventing and treating this complication using experimental models of spinal cord ischemia. The model described here demonstrates varying degrees of paraplegia that relate to the length of occlusion following thoracic aortic occlusion in a rat spinal cord ischemia model. A 2-Fr. balloon-tipped catheter was advanced through the femoral artery into the descending thoracic aorta until the catheter tip was placed at the left subclavian artery in anesthetized male Sprague-Dawley rats. Spinal cord ischemia was induced by inflating the catheter balloon. After a set period of occlusion (9, 10, or 11 min), the balloon was deflated. Neurologic assessment was performed using the motor deficit index at 24 h after surgery, and the spinal cord was harvested for histopathological examination. Rats that underwent 9 min of aortic occlusion showed mild and reversible motor impairment in the hind limb. Rats subjected to 10 min of aortic occlusion presented with moderate but reversible motor impairment. Rats subjected to 11 min of aortic occlusion displayed complete and persistent paralysis. The motor neurons in the spinal cord sections were more preserved in rats subjected to shorter duration of aortic occlusion. Researchers can achieve a reproducible hind limb motor deficit following thoracic aortic occlusion using this spinal cord ischemia model.

Efficient Generation of Dopamine Neurons by Synthetic Transcription Factor mRNAs.

Generation of functional dopamine (DA) neurons is an essential step for the development of effective cell therapy for Parkinson's disease (PD). The generation of DA neurons can be accomplished by overexpression of DA-inducible genes using virus- or DNA-based gene delivery methods. However, these gene delivery methods often cause chromosomal anomalies. In contrast, mRNA-based gene delivery avoids this problem and therefore is considered safe to use in the development of cell-based therapy. Thus, we used mRNA-based gene delivery method to generate safe DA neurons. In this study, we generated transformation-free DA neurons by transfection of mRNA encoding DA-inducible genes Nurr1 and FoxA2. The delivery of mRNA encoding dopaminergic fate inducing genes proved sufficient to induce naive rat forebrain precursor cells to differentiate into neurons exhibiting the biochemical, electrophysiological, and functional properties of DA neurons in vitro. Additionally, the generation efficiency of DA neurons was improved by the addition of small molecules, db-cAMP, and the adjustment of transfection timing. The successful generation of DA neurons using an mRNA-based method offers the possibility of developing clinical-grade cell sources for neuronal cell replacement treatment for PD.

Pharmacokinetic drug interaction study using fimasartan and rosuvastatin in healthy volunteers.

OBJECTIVE: This study evaluated the possible pharmacokinetic interactions between rosuvastatin and fimasartan, an angiotensin II type 1 (AT1) receptor blocker (ARB), approved in Korea for the treatment of mild to moderate hypertension. METHODS: In this open-label, multiple-dose, two-period, single-sequence study, the enrolled subjects were randomized into two separate parts (A and B). In part A, subjects received 120 mg of fimasartan alone for 7 days during period I, and 120 mg fimasartan with 20 mg rosuvastatin for 7 days during period II. In Part B, subjects received rosuvastatin alone, followed by concomitant administration of fimasartan, with the same doses used as in Part A. There was a 7-day washout between periods I and II. Serial blood samples were collected for up to 48 hours for fimasartan and for up to 72 hours for rosuvastatin after the last dose of each period to determine the steady-state pharmacokinetics of both drugs. RESULTS: The mean Cmax,ss and AUCτ,ss values of fimasartan were 258.03 ± 176.75 ng/mL and 746.52 ± 273.49 ng×h/mL for fimasartan alone, and 289.40 ± 231.44 ng/mL and 848.43 ± 267.45 ng×h/mL for fimasartan and rosuvastatin coadministration, respectively (p-values for Cmax,ss and AUCτ,ss, 0. 513 and 0.006, respectively). The mean Cmax,ss and AUCτ,ss values of rosuvastatin were 9.94 ± 4.48 ng/mL and 85.29 ± 36.25 ng×h/mL for rosuvastatin alone and 11.94 ± 8.47 ng/mL and 77.33 ± 38.71 ng×h/mL for fimasartan and rosuvastatin coadministration, respectively (p-values for Cmax,ss and AUCτ,ss, 0.066 and 0.009, respectively). The geometric mean ratio (GMR) and 90% confidence intervals (CI) for the Cmax,ss and AUCτ,ss of fimasartan (with/without rosuvastatin) were 1.109 (0.813 - 1.511) and 1.159 (1.061 - 1.265), respectively. The GMR and 90% CI for the Cmax,ss and AUCτ,ss of rosuvastatin (with/without fimasartan) were 1.090 (0.979 - 1.213) and 0.870 (0.804 - 0.940), respectively. CONCLUSIONS: These results suggest that fimasartan and rosuvastatin have no relevant pharmacokinetic drug-drug interactions. All treatments were well tolerated during this study, with no serious adverse effects.
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Germacrone Inhibits Estrogen Receptor α-Mediated Transcription in MCF-7 Breast Cancer Cells.

Estrogen receptor (ER)α-positive breast cancer cells regulate the expression of estrogen-responsive genes, which are involved in cell proliferation, differentiation, and cell cycle progression. Clinically, the inhibition of ERα-mediated gene expression in breast cancer cells has long been considered an effective way to prevent the development and progression of cancer. Germacrone, a terpenoid compound isolated from Rhizoma curcuma, has been known to have antitumor activity in various human cancer cell lines. However, the mechanism by which germacrone inhibits the proliferation of breast cancer cells is still unclear. Here, we demonstrated that germacrone inhibits ERα-mediated gene expression at the transcriptional level in MCF-7 cells. Germacrone inhibits the recruitment of ERα to the estrogen response element on chromatin and consequently compromises the binding of switch/sucrose non-fermentable chromatin remodeling complex and RNA polymerase II to target gene promoter, thereby inhibiting the estrogen-induced chromatin accessibility. In addition, germacrone efficiently potentiates the antitumor activity of methotrexate and 5-fluorouracil. Our results not only provide substantial molecular mechanism of germacrone on ERα-mediated signaling in breast cancer cells but also demonstrate the benefits of germacrone as a combination therapy with other drugs for the treatment of breast cancer. Copyright © 2016 John Wiley & Sons, Ltd.

PTEN Promotes Dopaminergic Neuronal Differentiation Through Regulation of ERK-Dependent Inhibition of S6K Signaling in Human Neural Stem Cells.

: Phosphatase and tension homolog (PTEN) is a widely known negative regulator of insulin/phosphatidylinositol 3-kinase (PI3K) signaling. The PI3K/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) and Ras-extracellular signal-regulated kinase (Ras-ERK) signaling pathways are the chief mechanisms controlling the survival, proliferation, and differentiation of neural stem cells (NSCs). However, the roles of PTEN in Akt/mTOR and ERK signaling during proliferation and neuronal differentiation of human NSCs (hNSCs) are poorly understood. Treatment of proliferating hNSCs with a specific inhibitor of PTEN or overexpression of the PTEN inactive mutant G129E resulted in an increase in the expression levels of Ki67, p-S6 kinase (p-S6K), and p-ERK without affecting p-Akt expression during proliferation of hNSCs. Therefore, we focused on the regulatory effect of PTEN in S6K and ERK signaling during dopaminergic neuronal differentiation of hNSCs. Overexpression of PTEN during neuronal differentiation of hNSCs caused an increase in p-S6K expression and a decrease in p-ERK expression. Conversely, inhibition of PTEN increased p-ERK expression and decreased p-S6K expression. Inhibition of ERK by a specific chemical inhibitor, U0126, promoted neuronal generation, especially of tyrosine hydroxylase-positive neurons. p-S6K expression increased in a time-dependent manner during differentiation, and this effect was enhanced by U0126. These results indicated that PTEN promoted neuronal differentiation by inhibition of ERK signaling, which in turn induced activation of S6K. Our data suggest that ERK pathways participate in crosstalk with S6K through PTEN signaling during neuronal differentiation of hNSCs. These results represent a novel pathway by which PTEN may modulate the interplay between ERK and S6K signaling, leading to increased neuronal differentiation in hNSCs. SIGNIFICANCE: This article adds to the body of knowledge about the mechanism of extracellular signal-regulated kinase (ERK)-mediated differentiation by describing the molecular function of phosphatase and tension homolog (PTEN) during the neuronal differentiation of human neural stem cells (hNSCs). Previous studies showed that S6K signaling promoted neuronal differentiation in hNSCs via the phosphatidylinositol 3-kinase Akt-mammalian target of rapamycin signaling pathway. A further series of studies investigated whether this S6 kinase-induced differentiation in hNSCs involves regulation of ERK signaling by PTEN. The current study identified a novel mechanism by which PTEN regulates neuronal differentiation in hNSCs, suggesting that activating PTEN function promotes dopaminergic neuronal differentiation and providing an important resource for future studies of PTEN function.

Evaluation of a Pharmacokinetic Interaction between Telmisartan and Chlorthalidone in Healthy Male Adult Subjects.

BACKGROUND AND OBJECTIVE: Combination therapy is recommended for the effective management of hypertension according to most treatment guidelines, including those of the US Joint National Committee. Therefore, pharmacokinetic drug interactions are an important issue in combination therapy for hypertension. In this study, the pharmacokinetic properties of telmisartan and chlorthalidone were evaluated to investigate their pharmacokinetic interactions in healthy subjects. METHODS: Two separate, randomized, multiple-dose, two-period, one-sequence studies were conducted. In study A, 43 participants received 80 mg of telmisartan orally for 7 days, and were then administered oral chlorthalidone 25 mg for 14 days (days 8-21), coadministered with 80 mg of telmisartan from day 15. In study B, 14 participants received oral chlorthalidone (25 mg) for 13 days, followed by coadministration with 80 mg of telmisartan orally for 7 days. RESULTS: The geometric mean ratios (GMRs) (90 % confidence intervals [CIs]) of the maximum plasma concentration (C max,ss) and area under the concentration-time curve for the dosing interval at steady state (AUCτ,ss) of telmisartan (with and without chlorthalidone) were 1.018 (0.861-1.203) and 1.099 (1.015-1.190), respectively. For chlorthalidone (with/without telmisartan), the GMRs (90 % CIs) for C max,ss and AUCτ,ss were 0.996 (0.922-1.075) and 0.992 (0.925-1.064), respectively. The GMRs and 90 % CIs for telmisartan and chlorthalidone were all within the 0.80-1.25 range. CONCLUSION: Thus, in this study, there was no significant pharmacokinetic interaction between telmisartan and chlorthalidone. CLINICALTRIAL. GOV IDENTIFIER: NCT01806363.

Follistatin-like 1 promotes osteoclast formation via RANKL-mediated NF-κB activation and M-CSF-induced precursor proliferation.

Follistatin-like 1 (FSTL1) functions as a pivotal modulator of inflammation and is implicated in many inflammatory diseases such as rheumatoid arthritis. Here, we report that FSTL1 is strongly upregulated and secreted during osteoclast differentiation of bone marrow-derived macrophages (BMMs) and that FSTL1 positively regulates osteoclast formation induced by RANKL and M-CSF. The overexpression of FSTL1 or treatment with recombinant FSTL1 (rFSTL1) in BMMs enhances the formation of multinuclear osteoclasts and the induction of c-Fos and NFATc1, transcription factors important for osteoclastogenesis. Conversely, knockdown of FSTL1 using a small hairpin RNA suppresses osteoclast formation and the expression of these transcription factors. While FSTL1 does not affect RANKL-stimulated activation of p38 MAPK, phosphorylation of IκBα, JNK, and ERK were increased by overexpression or addition of rFSTL1. Furthermore, rFSTL1 increased RANKL-induced NF-κB transcriptional activity in a dose-dependent manner. In addition to its role in osteoclastogenesis, FSTL1 promotes proliferation of osteoclast precursors by increasing M-CSF-induced ERK activation, which in turn leads to accelerated osteoclast formation. Together, our findings demonstrate that FSTL1 is a secreted osteoclastogenic factor that plays a critical role in osteoclast formation via the NF-κB and MAPKs signaling pathways.

Deficiency of Lipocalin-2 Promotes Proliferation and Differentiation of Osteoclast Precursors via Regulation of c-Fms Expression and Nuclear Factor-kappa B Activation.

BACKGROUND: Lipocalin-2 (LCN2), a small glycoprotein, has a pivotal role in diverse biological processes such as cellular proliferation and differentiation. We previously reported that LCN2 is implicated in osteoclast formation induced by receptor activator of nuclear factor-kappa B ligand (RANKL) and macrophage colony-stimulating factor (M-CSF). In the present study, we used a knockout mouse model to further investigate the role of LCN2 in osteoclast development. METHODS: Osteoclastogenesis was assessed using primary bone marrow-derived macrophages. RANKL and M-CSF signaling was determined by immunoblotting, cell proliferation by bromodeoxyuridine (BrdU) enzyme-linked immunosorbent assay (ELISA), and apoptosis by cell death detection ELISA. Bone morphometric parameters were determined using a micro-computed tomography system. RESULTS: Our results showed that LCN2 deficiency increases tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclast formation in vitro, a finding that reflects enhanced proliferation and differentiation of osteoclast lineage cells. LCN2 deficiency promotes M-CSF-induced proliferation of bone marrow macrophages (BMMs), osteoclast precursors, without altering their survival. The accelerated proliferation of LCN2-deficient precursors is associated with enhanced expression and activation of the M-CSF receptor, c-Fms. Furthermore, LCN2 deficiency stimulates the induction of c-Fos and nuclear factor of activated T cells c1 (NFATc1), key transcription factors for osteoclastogenesis, and promotes RANKL-induced inhibitor of kappa B (IκBα) phosphorylation. Interestingly, LCN2 deficiency does not affect basal osteoclast formation in vivo, suggesting that LCN2 might play a role in the enhanced osteoclast development that occurs under some pathological conditions. CONCLUSIONS: Our study establishes LCN2 as a negative modulator of osteoclast formation, results that are in accordance with our previous findings.

G Protein-Coupled Receptor 120 Signaling Negatively Regulates Osteoclast Differentiation, Survival, and Function.

G protein-coupled receptor 120 (GPR120) plays an important role in the regulation of inflammation and lipid metabolism. In this study, we investigated the role of GPR120 in osteoclast development and found that GPR120 regulates osteoclast differentiation, survival and function. We observed that GPR120 was highly expressed in osteoclasts compared to their precursors, bone marrow-derived macrophages (BMMs). Activation of GPR120 by its ligand GW9508 suppressed receptor activator of NF- κB ligand (RANKL)-induced osteoclast differentiation and the expression of nuclear factor of activated T cells c1 (NFATc1), a key modulator of osteoclastogenesis. GPR120 activation further inhibited the RANKL-stimulated phosphorylation of IκBα and JNK. In addition to osteoclast differentiation, GPR120 activation increased the apoptosis of mature osteoclasts by inducing caspase-3 and Bim expression. Activation of GPR120 also interfered with cell spreading and actin cytoskeletal organization mediated by M-CSF but not by RANKL. Coincident with the impaired cytoskeletal organization, GPR120 activation blocked osteoclast bone resorbing activity. Furthermore, knockdown of GPR120 using small hairpin RNA abrogated all these inhibitory effects on osteoclast differentiation, survival, and function. Together, our findings identify GPR120 as a negative modulator of osteoclast development that may be an attractive therapeutic target for bone-destructive diseases. J. Cell. Physiol. 231: 844-851, 2016. © 2015 Wiley Periodicals, Inc.

Promotion of Cortical Neurogenesis from the Neural Stem Cells in the Adult Mouse Subcallosal Zone.

Neurogenesis occurs spontaneously in the subventricular zone (SVZ) of the lateral ventricle in adult rodent brain, but it has long been debated whether there is sufficient adult neurogenesis in human SVZ. Subcallosal zone (SCZ), a posterior continuum of SVZ closely associated with posterior regions of cortical white matter, has also been reported to contain adult neural stem cells (aNSCs) in both rodents and humans. However, little is known whether SCZ-derived aNSC (SCZ-aNSCs) can produce cortical neurons following brain injury. We found that SCZ-aNSCs exhibited limited neuronal differentiation potential in culture and after transplantation in mice. Neuroblasts derived from SCZ initially migrated toward injured cortex regions following brain injury, but later exhibited apoptosis. Overexpression of anti-apoptotic bcl-xL in the SCZ by retroviral infection rescued neuroblasts from cell death in the injured cortex, but neuronal maturation was still limited, resulting in atrophy. In combination with Bcl-xL, infusion of brain-derived neurotropic factor rescued atrophy, and importantly, a subset of such SCZ-aNSCs differentiated and attained morphological and physiological characteristics of mature, excitatory neurons. These results suggest that the combination of anti-apoptotic and neurotrophic factors might enable the use of aNSCs derived from the SCZ in cortical neurogenesis for neural replacement therapy.

S6K Promotes Dopaminergic Neuronal Differentiation Through PI3K/Akt/mTOR-Dependent Signaling Pathways in Human Neural Stem Cells.

It has recently been reported that the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway regulates neuronal differentiation of neural stem cells (NSCs) derived from rats or mice and is essential for the self-renewal of human embryonic stem cells (hESCs). However, the roles of PI3K/Akt/mTOR signaling pathways during proliferation and dopaminergic neuronal differentiation of human neural stem cells (hNSCs) are poorly understood. In this study, we examined the effect of regulation of these intracellular signaling pathways in hNSCs on the potential to maintain proliferation and induce dopaminergic neuronal differentiation. Dopaminergic neuronal differentiation depended on the concentration of insulin in our culture system. Inhibition of PI3K/Akt with LY294002 reduced proliferation and inhibited dopaminergic neuronal differentiation of these cells. We also found that rapamycin, a specific inhibitor of mTOR, significantly reduced neuronal differentiation without affecting proliferation. Inhibition of the Akt/mTOR signaling pathway led to inhibition of p70 ribosomal S6 kinase (S6K) signaling, which reduced dopaminergic neuronal differentiation in hNSCs. Inhibition of S6K by a specific chemical inhibitor, PF-4708671 inhibited dopaminergic neuronal differentiation of hNSCs. As expected, transduction with a dominant negative S6K1 (S6K1-DN) construct impaired dopaminergic neuronal differentiation of hNSCs. Conversely, overexpression of constitutively active S6K1 (S6K1-CA) promoted dopaminergic neuronal differentiation of these cells. In a survival study, 4 weeks after transplantation, no or very few donor cells were viable in striata grafted with S6K1-DN-transduced hNSCs. In contrast, S6K1-CA-transduced hNSCs survived, integrated into striata to generate tubular masses of grafts and differentiated toward TH-positive cells. Taken together, these data demonstrated that insulin promotes dopaminergic neuronal differentiation through a PI3K/Akt/mTOR-dependent pathway and that S6K plays a critical role in dopaminergic neuronal differentiation in hNSCs.

Efficient induction of neural precursor cells from fibroblasts using stromal cell-derived inducing activity.

The direct lineage conversion of fibroblasts into neuronal or neural precursor cells (NPCs) has become a hot issue in recent years as an attractive approach in the field of stem cell regenerative medicine. In this study, we adopted the stromal feeder co-culture method during the early conversion period to enhance conversion efficiency. Stromal cells are often used in directed differentiation of dopaminergic (DA) neurons from pluripotent stem cells. We co-cultured rat embryonic fibroblasts (REFs) on γ-irradiated sonic hedgehog-overexpressing MS5 stromal (MS5-SHH) cells after transduction with Brn2, Ascl1, Myt1L, and BclxL-GFP (BAMXGFP) transcription factors to REFs. One week after co-culture, transduced cells (GFP+ cells) that proliferated on MS5-SHH cells were separated from MS5-SHH cells through a 40 µm cell strainer. Subsequently, the converted cells (GFP+ cells) were expanded on fibronectin-coated culture plates in NPC expansion medium. The induced NPCs (iNPCs) expressed NPC potential (NESTIN+/SOX2+) earlier than seen with non-co-culture methods and were efficiently differentiated into DA neurons by overexpression of Nurr1 and Foxa2 genes, which are specific transcription factors for midbrain DA neuron development. These observations indicated that direct conversion to NPCs using an MS5 stromal cells co-culture method is a suitable technique for efficient generation of iNPC/DA neurons from fibroblasts.

FGF8 is Essential for Functionality of Induced Neural Precursor Cell-derived Dopaminergic Neurons.

Induced neural precursor cells (iNPCs) are one source of transplantable dopaminergic neurons used in cell therapy for Parkinson's disease. In the present study, we demonstrate that iNPCs can be generated by transducing Brn2, Ascl1, Myt1L and Bcl-xL in a culture supplemented with several mitogens and subsequently can be differentiated to dopaminergic neurons (DA). However, studies have shown that iDA and/or iNPC-derived DA neurons using various conversion protocols have low efficiency. Here, we show that early exposure of FGF8 to fibroblasts efficiently improves differentiation of DA neurons. So our study demonstrates that FGF8 is a critical factor for generation of iNPC-derived DA neurons.

Noggin Over-Expressing Mouse Embryonic Fibroblasts and MS5 Stromal Cells Enhance Directed Differentiation of Dopaminergic Neurons from Human Embryonic Stem Cells.

Directed methods for differentiating human embryonic stem cells (hESCs) into dopaminergic (DA) precursor cells using stromal cells co-culture systems are already well established. However, not all of the hESCs differentiate into DA precursors using these methods. HSF6, H1, H7, and H9 cells differentiate well into DA precursors, but CHA13 and CHA15 cells hardly differentiate. To overcome this problem, we modified the differentiation system to include a co-culturing step that exposes the cells to noggin early in the differentiation process. This was done using γ-irradiated noggin-overexpressing CF1-mouse embryonic fibroblasts (MEF-noggin) and MS5 stromal cells (MS5-noggin and MS5-sonic hedgehog). After directed differentiation, RT-PCR analyses revealed that engrailed-1 (En-1), Lmx1b, and Nurr1, which are midbrain DA markers, were expressed regardless of differentiation stage. Moreover, tyrosine hydroxylase (Th) and an A9 midbrain-specific DA marker (Girk2) were expressed during differentiation, whereas levels of Oct3/4, an undifferentiated marker, decreased. Immunocytochemical analyses revealed that protein levels of the neuronal markers TH and TuJ1 increased during the final differentiation stage. These results demonstrate that early noggin exposure may play a specific role in the directed differentiation of DA cells from human embryonic stem cells.

Involvement of inflammation in Alzheimer's disease pathogenesis and therapeutic potential of anti-inflammatory agents.

Alzheimer's disease (AD) is the most common form of dementia. It is characterized by beta-amyloid (Aß) peptide fibrils, which are extracellular depositions of a specific protein, and is accompanied by extensive neuroinflammation. Various studies have demonstrated risk factors that can affect AD pathogenesis, and they include accumulation of Aß, hyperphosphorylation of tau protein, and neuroinflammation. Among these detrimental factors, neuroinflammation has been highlighted by epidemiologic studies suggesting that use of anti-inflammatory drugs could significantly reduce the incidence of AD. Evidence suggests that astrocytes, microglia, and infiltrating immune cells from periphery might contribute to or modify the process of neuroinflammation and neurodegeneration in AD brains. In addition, recent data indicate that microRNAs may affect neuroinflammatory responses in the brain. This article focuses on supportive evidence that neuroinflammation plays a critical role in AD development. In addition, we depict putative therapeutic capacity of anti-inflammatory drugs for AD prevention or treatment. We also discuss pathogenic mechanisms by which astrocytes, microglia, T cells and microRNA participate in AD and the neuroprotective mechanisms of anti-inflammatory drugs.