Primary cilia mediate sonic hedgehog signaling to regulate neuronal-like differentiation of bone mesenchymal stem cells for resveratrol induction in vitro

Role of Hedgehog Signaling Pathways in Multipotent Mesenchymal Stem Cells Differentiation

Multipotent mesenchymal stem cells (MSCs) have high self-renewal and multi-lineage differentiation potentials and low immunogenicity, so they have attracted much attention in the field of regenerative medicine and have a promising clinical application. MSCs originate from the mesoderm and can differentiate not only into osteoblasts, cartilage, adipocytes, and muscle cells but also into ectodermal and endodermal cell lineages across embryonic layers. To design cell therapy for replacement of damaged tissues, it is essential to understand the signaling pathways, which have a major impact on MSC differentiation, as this will help to integrate the signaling inputs to initiate a specific lineage. Hedgehog (Hh) signaling plays a vital role in the development of various tissues and organs in the embryo. As a morphogen, Hh not only regulates the survival and proliferation of tissue progenitor and stem populations but also is a critical moderator of MSC differentiation, involving tri-lineage and across embryonic layer differentiation of MSCs. This review summarizes the role of Hh signaling pathway in the differentiation of MSCs to mesodermal, endodermal, and ectodermal cells.

New insights into Sirt1: potential therapeutic targets for the treatment of cerebral ischemic stroke

Ischemic stroke is one of the main causes of mortality and disability worldwide. However, the majority of patients are currently unable to benefit from intravenous thrombolysis or intravascular mechanical thrombectomy due to the limited treatment windows and serious complications. Silent mating type information regulation 2 homolog 1 (Sirt1), a nicotine adenine dinucleotide-dependent enzyme, has emerged as a potential therapeutic target for ischemic stroke due to its ability to maintain brain homeostasis and possess neuroprotective properties in a variety of pathological conditions for the central nervous system. Animal and clinical studies have shown that activation of Sirt1 can lessen neurological deficits and reduce the infarcted volume, offering promise for the treatment of ischemic stroke. In this review, we summarized the direct evidence and related mechanisms of Sirt1 providing neuroprotection against cerebral ischemic stroke. Firstly, we introduced the protein structure, catalytic mechanism and specific location of Sirt1 in the central nervous system. Secondly, we list the activators and inhibitors of Sirt1, which are primarily divided into three categories: natural, synthetic and physiological. Finally, we reviewed the neuroprotective effects of Sirt1 in ischemic stroke and discussed the specific mechanisms, including reducing neurological deficits by inhibiting various programmed cell death such as pyroptosis, necroptosis, ferroptosis, and cuproptosis in the acute phase, as well as enhancing neurological repair by promoting angiogenesis and neurogenesis in the later stage. Our review aims to contribute to a deeper understanding of the critical role of Sirt1 in cerebral ischemic stroke and to offer novel therapeutic strategies for this condition.

Sirt1 regulates microglial activation and inflammation following oxygen-glucose deprivation/reoxygenation injury by targeting the Shh/Gli-1 signaling pathway

BACKGROUND

Cerebral ischemic injury leads to over-activation of microglia, which release pro-inflammatory factors that deteriorate neurological function during the acute phase of stroke. Thus, inhibiting microglial over-activation is crucial for reducing ischemic injury. Sirtuin 1 (Sirt1) has been shown to play a critical role in stroke, neurodegenerative diseases and aging. However, the effect of Sirt1 on the regulation of microglial activation following cerebral ischemic injury, as well as the underlying mechanism, remain unknown. Therefore, the purpose of the present study is to mainly investigate the effect of Sirt1 on oxygen-glucose deprivation/reoxygenation (OGD/R)-treated N9 microglia following treatment with the Sirt1 agonists resveratrol and SRT1720 and the Sirt1 antagonist sirtinol.

METHODS

Cell viability, Apoptosis, activation and inflammatory responses of microglia, expressions and activity of Shh signaling pathway proteins were detected by Cell Counting Kit 8, Flow Cytometry, immunocytochemistry, ELISA, and Western blotting, respectively.

RESULTS

The results demonstrated that treatment with resveratrol or SRT1720 could inhibit the activation of microglia and inflammation during OGD/R. Moreover, these treatments also led to the translocation of the GLI family zinc finger-1 (Gli-1) protein from the cytoplasm to the nucleus and upregulated the expression of Sonic hedgehog (Shh), Patched homolog-1 (Ptc-1), smoothened frizzled class receptor and Gli-1. By contrast, the inhibition of Sirt1 using sirtinol had the opposite effect.

CONCLUSION

These findings suggested that Sirt1 may regulate microglial activation and inflammation by targeting the Shh/Gli-1 signaling pathway following OGD/R injury. Schematic representation of Sirt1 regulating the microglial activation and inflammation following oxygen-glucose deprivation/reoxygenation injury via mediation of Shh/Gli-1 signaling pathway.

Resveratrol Inhibits Activation of Microglia after Stroke through Triggering Translocation of Smo to Primary Cilia

Activated microglia act as a double-edged sword for stroke. In the acute phase of stroke, activated microglia might deteriorate neurological function. Therefore, it is of great clinical transforming potential to explore drugs or methods that can inhibit abnormal activation of microglia in the acute phase of stroke to improve neurological function after stroke. Resveratrol has a potential effect of regulating microglial activation and anti-inflammation. However, the molecular mechanism of resveratrol-inhibiting microglial activation has not been fully clarified. Smoothened (Smo) belongs to the Hedgehog (Hh) signaling pathway. Smo activation is the critical step that transmits the Hh signal across the primary cilia to the cytoplasm. Moreover, activated Smo can improve neurological function via regulating oxidative stress, inflammation, apoptosis, neurogenesis, oligodendrogenesis, axonal remodeling, and so on. More studies have indicated that resveratrol can activate Smo. However, it is currently unknown whether resveratrol inhibits microglial activation via Smo. Therefore, in this study, N9 microglia in vitro and mice in vivo were used to investigate whether resveratrol inhibited microglial activation after oxygen-glucose deprivation/reoxygenation (OGD/R) or middle cerebral artery occlusion/reperfusion (MCAO/R) injury and improved functional outcome via triggering translocation of Smo in primary cilia. We definitively found that microglia had primary cilia; resveratrol partially inhibited activation and inflammation of microglia, improved functional outcome after OGD/R and MCAO/R injury, and triggered translocation of Smo to primary cilia. On the contrary, Smo antagonist cyclopamine canceled the above effects of resveratrol. The study suggested that Smo receptor might be a therapeutic target of resveratrol for contributing to inhibit microglial activation in the acute phase of stroke.

Stem cells' centrosomes: How can organelles identified 130 years ago contribute to the future of regenerative medicine?

At the core of regenerative medicine lies the expectation of repair or replacement of damaged tissues or whole organs. Donor scarcity and transplant rejection are major obstacles, and exactly the obstacles that stem cell-based therapy promises to overcome. These therapies demand a comprehensive understanding of the asymmetric division of stem cells, i.e. their ability to produce cells with identical potency or differentiated cells. It is believed that with better understanding, researchers will be able to direct stem cell differentiation. Here, we describe extraordinary advances in manipulating stem cell fate that show that we need to focus on the centrosome and the centrosome-derived primary cilium. This belief comes from the fact that this organelle is the vehicle that coordinates the asymmetric division of stem cells. This is supported by studies that report the significant role of the centrosome/cilium in orchestrating signaling pathways that dictate stem cell fate. We anticipate that there is sufficient evidence to place this organelle at the center of efforts that will shape the future of regenerative medicine.

Resveratrol-mediated neurorestoration after cerebral ischemic injury - Sonic Hedgehog signaling pathway

AIMS

Resveratrol pretreatment can decrease ischemic cerebral injury and enhance proliferation of neural stem cells via mediation of Sonic Hedgehog signaling. However, it is relatively little known about whether neurorestorative effects of resveratrol are mediated by Shh signaling in ischemic cerebral injury. The present study tests whether the Shh signaling pathway mediates resveratrol to promote neurorestoration of ischemic cerebral injury.

MATERIALS AND METHODS

Rats or neurons before middle cerebral artery occlusion/reperfusion (MCAO/R) or oxygen-glucose deprivation/reoxygenation (OGD/R) injury were pretreated with resveratrol. Immunohistochemistry is used to be determined BrdU+/DCX+, BrdU+/Nestin+ and BrdU+/NG2+ cell (markers of new proliferated neural stem/progenitor and oligodendrocyte precursor cell, respectively), BrdU+/MAP2+ and BrdU+/CNPase+ cell (markers of new mature neuron and oligodendrocyte, respectively), BrdU+/TUNEL+ cell (marker of apoptosis for new proliferated cell), SY, NF200, Iba-1 and GFAP (markers of synaptogenesis, axon, microglia and astrocyte, respectively). Shh and Gli-1 mRNAs were detected by RT-PCR assay. Iba-1, GFAP, Shh and Gli-1 proteins were detected by Western blot.

KEY FINDINGS

Resveratrol pretreatment significantly reduced neurological deficit scores, promoted proliferation, differentiation, migration and survival of neural stem/progenitor and oligodendrocyte precursor cells, inhibited astrocyte and microglia activation, strengthened synaptophysin and NF200 expression, at the same time, promoted neurite outgrowth of neurons. Meanwhile, expression levels of Shh and Gli-1 proteins were significantly increased and Gli-1 translocated into the nucleus. However, cyclopamine, a Smo inhibitor, canceled the above effects of resveratrol.

CONCLUSIONS

It may be mediated, at least partly, by the Shh signaling pathway that resveratrol pretreament promote neurorestoration of ischemic cerebral injury.

Effect of Active Ingredients of Chinese Herbal Medicine on the Rejuvenation of Healthy Aging: Focus on Stem Cells

Stem cells (SCs) are special types of cells with the ability of self-renewal and multidirectional differentiation. As the organism ages, the ability to maintain homeostasis and regeneration deteriorates and the number and activity of stem cells decline. Theoretically, the restoration of stem cells might reverse aging. However, due to their own aging, donor-derived immune rejection, and difficulties in stem cell differentiation control, a series of problems need to be solved to realize the potential for clinical application of stem cells. Chinese herbal medicine is a nature drug library which is suitable for the long-term treatment of aging-related diseases. Modern pharmacological studies have revealed that many active ingredients of Chinese herbal medicines with the effect of promoting stem cells growth and differentiation mainly belong to “reinforcing herbs.” In recent years, exploration of natural active ingredients from Chinese herbal medicines for delaying aging, improving the stem cell microenvironment, and promoting the proliferation and differentiation of endogenous stem cells has attracted substantial attention. This article will focus on active ingredients from Chinese herbs-mediated differentiation of stem cells into particular cell type, like neural cells, endothelial cells, cardiomyocytes, and osteoblasts. We will also discuss the effects of these small molecules on Wnt, Sonic Hedgehog, Notch, eNOS-cGMP, and MAP kinase signal transduction pathways, as well as reveal the role of estrogen receptor α and PPAR γ on selectively promoting or inhibiting stem cells differentiation. This review will provide new insights into the health aging strategies of active ingredients in Chinese herbal medicine in regenerative medicine.

Metabonomic-Transcriptome Integration Analysis on Osteoarthritis and Rheumatoid Arthritis

Purpose

This study is aimed at exploring the potential metabolite/gene biomarkers, as well as the differences between the molecular mechanisms, of osteoarthritis (OA) and rheumatoid arthritis (RA).

Methods

Transcriptome dataset GSE100786 was downloaded to explore the differentially expressed genes (DEGs) between OA samples and RA samples. Meanwhile, metabolomic dataset MTBLS564 was downloaded and preprocessed to obtain metabolites. Then, the principal component analysis (PCA) and linear models were used to reveal DEG-metabolite relations. Finally, metabolic pathway enrichment analysis was performed to investigate the differences between the molecular mechanisms of OA and RA.

Results

A total of 976 DEGs and 171 metabolites were explored between OA samples and RA samples. The PCA and linear module analysis investigated 186 DEG-metabolite interactions including Glycogenin 1- (GYG1-) asparagine_54, hedgehog acyltransferase- (HHAT-) glucose_70, and TNF receptor-associated factor 3- (TRAF3-) acetoacetate_35. Finally, the KEGG pathway analysis showed that these metabolites were mainly enriched in pathways like gap junction, phagosome, NF-kappa B, and IL-17 pathway.

Conclusions

Genes such as HHAT, GYG1, and TRAF3, as well as metabolites including glucose, asparagine, and acetoacetate, might be implicated in the pathogenesis of OA and RA. Metabolites like ethanol and tyrosine might participate differentially in OA and RA progression via the gap junction pathway and phagosome pathway, respectively. TRAF3-acetoacetate interaction may be involved in regulating inflammation in OA and RA by the NF-kappa B and IL-17 pathway.

Deficient primary cilia in obese adipose-derived mesenchymal stem cells: obesity, a secondary ciliopathy?

Obesity alters the composition, structure and function of adipose tissue, characterized by chronic inflammation, insulin resistance and metabolic dysfunction. Adipose-derived mesenchymal stem cells (ASCs) are responsible for cell renewal, spontaneous repair and immunomodulation in adipose tissue. Increasing evidence highlights that ASCs are deficient in obesity, and the underlying mechanisms are not well understood. We have recently shown that obese ASCs have defective primary cilia, which are shortened and unable to properly respond to stimuli. Impaired cilia compromise ASC functions. This work suggests an intertwined connection of obesity, defective cilia and dysfunctional ASCs. We have here discussed the current data regarding defective cilia in various cell types in obesity. Based on these observations, we hypothesize that obesity, a systemic chronic metainflammation, could impair cilia in diverse ciliated cells, like pancreatic islet cells, stem cells and hypothalamic neurons, making these critical cells dysfunctional by shutting down their signal sensors and transducers. In this context, obesity may represent a secondary form of ciliopathy induced by obesity-related inflammation and metabolic dysfunction. Reactivation of ciliated cells might be an alternative strategy to combat obesity and its associated diseases.

Potential Non-neoplastic Applications for Polyphenols in Stem Cell Utilization

While polyphenols may have important effects on pluripotential stem cells that make them noteworthy as potential antineoplastic agents, their action on stem cells may portend other health benefits, such as treatments for cardiovascular and neurocognitive disorders. Resveratrol, the beststudied polyphenol, has been found to enable stem cells to differentiate into cardiomyocytes, neurons, osteocytes, and pancreatic beta cells, as well as facilitating augmentation of stem cell populations and protecting them from toxic injury. Curcumin protects mesenchymal stem cells from toxicity, and prevents them from facilitating chondrocytic hypertrophy. Quercetin enabled osteocytic and pancreatic beta cell differentiation, and protected neuronal stem cells from injury. Epigallocatechin gallate prevented damage to osteocyte precursors and averted differentiation into undesirable adipocytes. Genistein facilitated osteogenesis while preventing adipogenesis. Several other polyphenols, daidzein, caffeic and chlorogenic acid, kaempferol, and piceatannol, protect stems cells from reactive oxygen species and foster stem cells differentiation away from adipocytic and toward osteocytic lineages. Further research should better elucidate the pharmacokinetic profiles of each polyphenol, explore novel delivery systems, and expand investigation beyond rodent models to additional species.

Sonic hedgehog signaling mediates resveratrol to improve maturation of pig oocytes in vitro and subsequent preimplantation embryo development

The beneficial effects of resveratrol on in vitro maturation (IVM) have been explained mainly by indirect antioxidant effects and limited information is available on the underlying mechanism by which resveratrol acts directly on porcine cumulus oocyte complexes (COCs). Recently, several studies reported that sonic hedgehog (SHH) signaling mediates resveratrol to exert its biological activities. Furthermore, SHH is an important signaling molecule for follicle development, oocyte maturation, and embryo development. Therefore, to elucidate the relationship between resveratrol and SHH signaling, we designed three groups: (i) control; (ii) resveratrol; and (iii) resveratrol with cyclopamine (SHH signaling inhibitor). We evaluated the effects of these agents on cumulus expansion, oocyte maturation, embryo development after parthenogenetic activation, expression levels of mRNAs in cumulus cells, oocytes and blastocysts, and protein expression in COCs. Resveratrol significantly increased the proportion of COCs exhibiting complete cumulus expansion (degree 4), oocyte nuclear maturation, cleavage and blastocyst formation rates and total cell numbers, which were blocked in the presence of cyclopamine. At the same time, a significant increase in the expression levels of mRNAs related to cumulus expansion, oocyte maturation and SHH signaling-related mRNAs and proteins from the resveratrol treatment group was also inhibited by simultaneous addition of cyclopamine. In conclusion, our results indicate that SHH signaling mediates resveratrol to improve porcine cumulus expansion, oocyte maturation, and subsequent embryo development.

Sonic hedgehog (SHH) signaling improves the angiogenic potential of Wharton's jelly-derived mesenchymal stem cells (WJ-MSC)

Background

Wharton’s jelly-derived mesenchymal stem cells (WJ-MSC) show remarkable therapeutic potential to repair tissue upon injury via paracrine signaling by secreting diverse trophic factors that promote angiogenesis. However, the mechanisms and signaling pathways that regulate the induction of these specific factors are still mostly unknown. Emerging evidence suggests that Sonic hedgehog (SHH) plays a central role in angiogenesis and tissue maintenance. However, its contribution to the angiogenic potential of MSC has not been fully addressed. The aim of this work was to characterize the expression of the SHH pathway components in WJ-MSC primary cultures and to evaluate their angiogenic responsiveness to SHH signaling.

Methods

Primary cell cultures obtained from human umbilical cords were treated with pharmacological modulators of the SHH pathway. We evaluated the modulation of diverse trophic factors in cell lysates, conditioned medium, and functional in vitro assays. In addition, we determined the angiogenic potential of the SHH pathway in the chicken chorioallantoic membrane, an in vivo model.

Results

Our results show that WJ-MSC express components of the canonical SHH pathway and are activated by its signaling. In fact, we provide evidence of basal autocrine/paracrine SHH signaling in WJ-MSC. SHH pathway stimulation promotes the secretion of angiogenic factors such as activin A, angiogenin, angiopoietin 1, granulocyte-macrophage colony-stimulating factor, matrix metallometallopeptidase -9, and urokinase-type plasminogen activator, enhancing the pro-angiogenic capabilities of WJ-MSC both in vitro and in vivo.

Conclusion

WJ-MSC are a cell population responsive to SHH pathway stimulation. Basal SHH signaling is in part responsible for the angiogenic inductive properties of WJ-MSC. Overall, exogenous activation of the SHH pathway enhances the angiogenic properties of WJ-MSC, making this cell population an ideal target for treating tissue injury.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0653-8) contains supplementary material, which is available to authorized users.

Differentiation of human dental pulp stem cells into neuronal by resveratrol

Dental pulp stem cells (DPSCs) have been proposed as a promising source of stem cells in nerve regeneration due to their close embryonic origin and ease of harvest. Resveratrol (RSV) is a natural polyphenolic and possesses many biological functions such as anti-inflammatory activity and protection against atherosclerosis and neuroprotective activities. There is increasing evidence showing that RSV plays a pivotal role in neuron protection and neuronal differentiation. In this study, we isolated DPSCs from impacted third molars and investigated whether RSV induces neuronal differentiation of DPSCs. To avoid loss of DPSCs multipotency, all the experiments were conducted on cells at early passages. RT-PCR results showed that RSV-treated DPSCs (RSV-DPSCs) significantly increased the expression of the neuroprogenitor marker Nestin. When RSV-DPSCs were differentiated with neuronal induction media (RSV-dDPSCs), they showed a cell morphology similar to neurons. The expression of neuronal-specific marker genes Nestin, Musashi, and NF-M in RSV-dDPSCs was significantly increased. Immunocytochemical staining and Western blot analysis showed that the expression of neuronal marker proteins, Nestin, and NF-M, was significantly increased in RSV-dDPSCs. Therefore, we have shown that RSV treatment, along with the use of neuronal induction media, effectively promotes neuronal cell differentiation of DPSCs.

Static pressure-induced neural differentiation of mesenchymal stem cells

Growing experimental evidence suggests that physical cues play an important role in regulating the fate of stem cells and stimulating their differentiation behavior. We report here that static pressure enables the differentiation of rat bone marrow-derived mesenchymal stem cells (MSCs) into neural-like cells within several hours in the absence of disruptive bio-factors or chemicals. The realization of such differentiation is supported by the observation of characteristic morphology of neural-like cells with neurites, and an up-regulated expression level of neural-specific markers. Our finding also demonstrates the utility of the static pressure-based approach for in situ and specifically localized creation of neural cell systems, thereby providing profound implications for developing therapeutic application of stem cells.

The Multifaceted Roles of Primary Cilia in the Regulation of Stem Cell Properties and Functions

Stem cells are a unique class of cells that are capable of self-renewal and differentiation into multiple lineages. An increasing number of studies have suggested that both embryonic and adult stem cells possess primary cilia, antenna-like structures protruding from cell surfaces that are critical for sensing and transducing environmental cues. The primary cilium appears to regulate stem cells in multiple aspects, such as lineage specification and stemness maintenance. Understanding the role of primary cilia in the control of stem cell behavior could lead to the identification of new targets for regenerative therapies. Here, we discuss recent studies investigating the diverse roles of primary cilia in the regulation of stem cell properties and functions. We also propose potential new avenues for exploration in this promising field. J. Cell. Physiol. 232: 935-938, 2017. © 2016 Wiley Periodicals, Inc.

Resveratrol Pretreatment Decreases Ischemic Injury and Improves Neurological Function Via Sonic Hedgehog Signaling After Stroke in Rats

Resveratrol has neuroprotective effects for ischemic cerebral stroke. However, its neuroprotective mechanism for stroke is less well understood. Beneficial actions of the activated Sonic hedgehog (Shh) signaling pathway in stroke, such as improving neurological function, promoting neurogenesis, anti-oxidative, anti-apoptotic, and pro-angiogenic effects, have been noted, but relatively little is known about the role of Shh signaling in resveratrol-reduced cerebral ischemic injury after stroke. The present study tests whether the Shh pathway mediates resveratrol to decrease cerebral ischemic injury and improve neurological function after stroke. We observed that resveratrol pretreatment significantly improved neurological function, decreased infarct volume, enhanced vitality, and reduced apoptosis of neurons in vivo and vitro after stroke. Meanwhile, expression levels of Shh, Ptc-1, Smo, and Gli-1 mRNAs were significantly upregulated and Gli-1 was relocated to the nucleus. Intriguingly, in vivo and in vitro inhibition of the Shh signaling pathway with cyclopamine, a Smo inhibitor, completely reversed the above effects of resveratrol. These results suggest that decreased cerebral ischemic injury and improved neurological function by resveratrol may be mediated by the Shh signaling pathway.

Reversion of malignant phenotypes of human glioblastoma cells by β-elemene through β-catenin-mediated regulation of stemness-, differentiation- and epithelial-to-mesenchymal transition-related molecules

Background

Glioblastoma is the most common and lethal type of primary brain tumor. β-Elemene, a natural plant drug extracted from Curcuma wenyujin, has shown strong anti-tumor effects in various tumors with low toxicity. However, the effects of β-elemene on malignant phenotypes of human glioblastoma cells remain to be elucidated. Here we evaluated the effects of β-elemene on cell proliferation, survival, stemness, differentiation and the epithelial-to-mesenchymal transition (EMT) in vitro and in vivo, and investigated the mechanisms underlying these effects.

Methods

Human primary and U87 glioblastoma cells were treated with β-elemene, cell viability was measured using a cell counting kit-8 assay, and treated cells were evaluated by flow cytometry. Western blot analysis was carried out to determine the expression levels of stemness markers, differentiation-related molecules and EMT-related effectors. Transwell assays were performed to further determine EMT of glioblastoma cells. To evaluate the effect of β-elemene on glioblastoma in vivo, we subcutaneously injected glioblastoma cells into the flank of nude mice and then intraperitoneally injected NaCl or β-elemene. The tumor xenograft volumes were measured every 3 days and the expression of stemness-, differentiation- and EMT-related effectors was determined by Western blot assays in xenografts.

Results

β-Elemene inhibited proliferation, promoted apoptosis, impaired invasiveness in glioblastoma cells and suppressed the growth of animal xenografts. The expression levels of the stemness markers CD133 and ATP-binding cassette subfamily G member 2 as well as the mesenchymal markers N-cadherin and β-catenin were significantly downregulated, whereas the expression levels of the differentiation-related effectors glial fibrillary acidic protein, Notch1, and sonic hedgehog as well as the epithelial marker E-cadherin were upregulated by β-elemene in vitro and in vivo. Interestingly, the expression of vimentin was increased by β-elemene in vitro; this result was opposite that for the in vivo procedure. Inhibiting β-catenin enhanced the anti-proliferative, EMT-inhibitory and specific marker expression-regulatory effects of β-elemene.

Conclusions

β-Elemene reversed malignant phenotypes of human glioblastoma cells through β-catenin-involved regulation of stemness-, differentiation- and EMT-related molecules. β-Elemene represents a potentially valuable agent for glioblastoma therapy.

Using the avian mutant talpid2 as a disease model for understanding the oral-facial phenotypes of oral-facial-digital syndrome

Oral-facial-digital syndrome (OFD) is a ciliopathy that is characterized by oral-facial abnormalities, including cleft lip and/or palate, broad nasal root, dental anomalies, micrognathia and glossal defects. In addition, these individuals have several other characteristic abnormalities that are typical of a ciliopathy, including polysyndactyly, polycystic kidneys and hypoplasia of the cerebellum. Recently, a subset of OFD cases in humans has been linked to mutations in the centriolar protein C2 Ca(2+)-dependent domain-containing 3 (C2CD3). Our previous work identified mutations in C2CD3 as the causal genetic lesion for the avian talpid(2) mutant. Based on this common genetic etiology, we re-examined the talpid(2) mutant biochemically and phenotypically for characteristics of OFD. We found that, as in OFD-affected individuals, protein-protein interactions between C2CD3 and oral-facial-digital syndrome 1 protein (OFD1) are reduced in talpid(2) cells. Furthermore, we found that all common phenotypes were conserved between OFD-affected individuals and avian talpid(2) mutants. In light of these findings, we utilized the talpid(2) model to examine the cellular basis for the oral-facial phenotypes present in OFD. Specifically, we examined the development and differentiation of cranial neural crest cells (CNCCs) when C2CD3-dependent ciliogenesis was impaired. Our studies suggest that although disruptions of C2CD3-dependent ciliogenesis do not affect CNCC specification or proliferation, CNCC migration and differentiation are disrupted. Loss of C2CD3-dependent ciliogenesis affects the dispersion and directional persistence of migratory CNCCs. Furthermore, loss of C2CD3-dependent ciliogenesis results in dysmorphic and enlarged CNCC-derived facial cartilages. Thus, these findings suggest that aberrant CNCC migration and differentiation could contribute to the pathology of oral-facial defects in OFD.

Adipogenic Differentiation of hMSCs is Mediated by Recruitment of IGF-1r Onto the Primary Cilium Associated With Cilia Elongation

Primary cilia are single non-motile organelles that provide a highly regulated compartment into which specific proteins are trafficked as a critical part of various signaling pathways. The absence of primary cilia has been shown to prevent differentiation of human mesenchymal stem cells (hMSCs). Changes in primary cilia length are crucial for regulating signaling events; however it is not known how alterations in cilia structure relate to differentiation. This study tested the hypothesis that changes in primary cilia structure are required for stem cell differentiation. hMSCs expressed primary cilia that were labeled with acetylated alpha tubulin and visualized by confocal microscopy. Chemically induced differentiation resulted in lineage specific changes in cilia length and prevalence which were independent of cell cycle. In particular, adipogenic differentiation resulted in cilia elongation associated with the presence of dexamethasone, while insulin had an inhibitory effect on cilia length. Over a 7-day time course, adipogenic differentiation media resulted in cilia elongation within 2 days followed by increased nuclear PPARγ levels; an early marker of adipogenesis. Cilia elongation was associated with increased trafficking of insulin-like growth factor-1 receptor β (IGF-1Rβ) into the cilium. This was reversed on inhibition of elongation by IFT-88 siRNA transfection, which also decreased nuclear PPARγ. This is the first study to show that adipogenic differentiation requires primary cilia elongation associated with the recruitment of IGF-1Rβ onto the cilium. This study may lead to the development of cilia-targeted therapies for controlling adipogenic differentiation and associated conditions such as obesity.

BIX-01294-induced autophagy regulates elongation of primary cilia

Previously, we showed that BIX-01294 treatment strongly activates autophagy. Although, the interplay between autophagy and ciliogenesis has been suggested, the role of autophagy in ciliogenesis is controversial and largely unknown. In this study, we investigated the effects of autophagy induced by BIX-01294 on the formation of primary cilia in human retinal pigmented epithelial (RPE) cells. Treatment of RPE cells with BIX-01294 caused strong elongation of the primary cilium and increased the number of ciliated cells, as well as autophagy activation. The elongated cilia in serum starved cultured cells were gradually decreased by re-feeding the cells with normal growth medium. However, the disassembly of cilia was blocked in the BIX-01294-treated cells. In addition, both genetic and chemical inhibition of autophagy suppressed BIX-01294-mediated ciliogenesis in RPE cells. Taken together, these results suggest that autophagy induced by BIX-01294 positively regulates the elongation of primary cilium.

Immunofluorescence Microscopy and mRNA Analysis of Human Embryonic Stem Cells (hESCs) Including Primary Cilia Associated Signaling Pathways

This chapter describes the procedures for immunofluorescence microscopy (IFM) and quantitative PCR (qPCR) analyses of human embryonic stem cells (hESCs) grown specifically under feeder-free conditions. A detailed protocol is provided outlining the steps from initially growing the cells, passaging onto 16-well glass chambers, and continuing with the general IFM and qPCR anlysis. The techniques are illustrated with results on cellular localization of transcriptional factors and components of the Hedgehog, Wnt, PDGF, and TGFβ signaling pathways to primary cilia in stem cell maintenance and differentiation. Furthermore, a sample qPCR experiment is experimentally shown illustrating that these techniques can be important tools in answering basic questions about hESC biology.