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At least 19 records

Cardiac extracellular matrix hydrogel together with or without inducer cocktail improves human adipose tissue-derived stem cells differentiation into cardiomyocyte–like cells

Studies have demonstrated that differentiation of stem cells into cardiomyocytes is a complex phenomenon that requires sufficient inducing factors at various time points. Cardiac extracellular matrix (cECM) could provide tissue specific microenvironment and act as an inductive template for efficient cell differentiation. The aim of this study was to investigate the effect of cECM on differentiation of human adipose tissue-derived stem cells (hADSCs) into cardiomyocytes using cECM hydrogel in combination with a cardiac inductive cocktail. hADSCs were cultured on ECM-coated plates with and without inductive cocktail for 3weeks. qRT-PCR and western blot analysis were used to evaluate the expression pattern of special cardiac genes and proteins. When hADSCs were cultured in the presence of cECM cardiac genes including GATA4, HAND1, HAND2, NKX2.5, Troponin I, βMHC, Connexin43 were highly expressed in differentiated cells. Also Connexin43, cTnI and βMHC proteins were expressed as well. We could show that cECM by itself could affect viability, proliferation and differentiation of hADSCs. However, combination of cECM with a cardiac inducing cocktail could improve the results.

60 APPLIED LIFE SCIENCES↗

Promoting hepatogenic differentiation of human mesenchymal stem cells using a novel laminin-containing gelatin cryogel scaffold

Highlights: • The gelatin cryogel was optimized for stability in cell culture medium during stem cell differentiation. • The optimized gelatin cryogel improved with the laminin, the main component of basal lamina. • The novel scaffold with laminin efficiently enhanced differentiation of mesenchymal stem cells toward hepatocyte lineage. Liver transplantation is the only definitive treatment currently available for acute and chronic liver failure. However, this approach has been restricted by complications including rejection and infection. Tissue engineering approaches using stem cell-derived functional hepatic cells offer a potential alternative. Using biologically compatible scaffolds is an important complementary key to achieve optimal construct for hepatic replacement. In the present study, to optimize the differentiation of human adipose-derived mesenchymal stem cells (ADMSCs) toward hepatocyte-like cells, a previously described gelatin cryogel was optimized and improved by laminin, the major component of basal lamina. The ADMSCs seeded on the scaffold displayed increased attachment in the presence of laminin and the MTT assay showed good compatibility for cell proliferation. The differentiation of stem cells were evaluated using glycogen staining, urea secretion measurement, hepatocyte specific cell surface analysis and gene expression analysis. The results of tests indicated that laminin protein and gelatin cryogel 3D scaffold, each on its own, enhanced hepatogenic differentiation of ADMSCs. However, when laminin immobilized on the gelatin cryogel surface, the differentiation was promoted significantly and the resulting cells showed striking similarity to HepG2 in terms of expressing studied hepatocyte markers.

60 APPLIED LIFE SCIENCES↗

Osteogenic differentiation of human adipose derived stem cells on chemically crosslinked carbon nanomaterial coatings

Abstract Carbon nanomaterial coatings have been widely investigated for many biomedical applications including bone tissue engineering. Current methods to fabricate carbon nanomaterial coatings are limited by specific substrate requirements and the lack of strong bonds between the nanomaterials. Furthermore, few studies compare the effect of carbon nanoparticle architecture on stem cell differentiation and mineralization for osteogenic differentiation. Herein, we report a study comparing chemically crosslinked carbon nanotubes (of various diameters), graphene nanoplatelets, and graphene nanoribbons coatings for adipose derived stem cell differentiation toward an osteogenic lineage. We observed greatest autodeposition of calcium on graphene nanoribbon surfaces, while multiwalled carbon nanotubes of high diameter had the greatest influence on stem cell fate (by alkaline phosphatase activity, calcium deposition, and osteocalcin measurements). Studies indicate the cause for multiwalled carbon nanotube related stem cell differentiation, may be related to early timepoint toxicity as indicated by lactose dehydrogenase release. These results indicate suggestions for orthopedic tissue engineering applications for carbon nanomaterial coatings. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1189–1199, 2018.

Patel, Sunny C.↗

Analysis of ionizing radiation induced DNA damage response in human adult stem cells and differentiated neurons

Findings of neurodegenerative features associated with human radiosensitive syndromes such as Ataxia telangiectasia suggest that DNA repair efficiency is crucial for maintaining the functional integrity of central nervous system. To gain a better understanding of ionizing radiation (IR) induced DNA damage response in undifferentiated and differentiated neural cell types and to evaluate the role of ATM in DNA double strand break (DSB) repair, an in vitro human neural cell differentiation model system was utilized in this study. As compared to adult stem cells, differentiated neurons displayed an attenuated DSB repair response (as judged by the persistence of 53BP1 foci) after IR exposure and the attenuation was even more pronounced in stem cells and neurons after suppression of ATM (Ataxia Telangiectasia Mutated) gene product suggesting the importance of ATM for an optimal DSB repair efficiency in human neural cell types. In corroboration with an attenuated DNA damage response, a sharp decline in the expression levels of several DSB repair genes was observed in neurons. Furthermore, our results suggest that cellular differentiation modulates the expression of several genes thereby compromising the DSB repair fidelity in post mitotic neurons. Further studies are required to verify whether or not ATM mediated exacerbation of DNA repair deficiency in differentiated neurons leads to neurodegeneration.

53 binding protein 1↗

Long non-coding RNA, Bmcob, regulates osteoblastic differentiation of bone marrow mesenchymal stem cells

Disordered osteoblastic differentiation of bone marrow mesenchymal stem cells (BMSCs) contributes to bone loss. The underlying mechanisms are complicated and not fully understood. Long non-coding RNAs (lncRNAs) are emerging as an important regulatory factors on bone metabolism. Here, we discovered a novel lncRNA, Bmcob, which modulated osteogenic differentiation of primary mouse BMSCs. Expression levels of Bmcob were significantly upregulated in early-to-mid stages during osteoblast differentiation. Silencing of Bmcob suppressed osteoblastic differentiation of BMSCs in vitro, whereas its overexpression protected BMSCs from oxidative stress induced inhibition on osteogenesis. Subsequently, we discovered that selenoprotein P (Sepp1), which is located next to the Bmcob gene, was partly responsible for the regulatory effects of Bmcob. In addition, a series of selenoproteins were downregulated in BMSCs with Bmcob knockdown. Mechanistically, we found Bmcob was associated with selenocysteine insertion sequence binding protein 2 (SBP2), a critical trans-acting factor for selenoprotein synthesis. Finally, we suggest an explanatory hypothesis that through modulating nucleocytoplasmic shuttling of SBP2, Bmcob regulates a number of selenoproteins expression, including sepp1, and then mediates osteogenesis of BMSCs. Taken together, our results revealed a novel mechanism regulating osteogenesis of BMSCs and may function as a potential target for treating osteoporosis.

60 APPLIED LIFE SCIENCES↗

Effective Labeling of Primary Somatic Stem Cells with BaTiO 3 Nanocrystals for Second Harmonic Generation Imaging

Abstract While nanoparticles are an increasingly popular choice for labeling and tracking stem cells in biomedical applications such as cell therapy, their intracellular fate and subsequent effect on stem cell differentiation remain elusive. To establish an effective stem cell labeling strategy, the intracellular nanocrystal concentration should be minimized to avoid adverse effects, without compromising the intensity and persistence of the signal necessary for long‐term tracking. Here, the use of second‐harmonic generating barium titanate nanocrystals is reported, whose achievable brightness allows for high contrast stem cell labeling with at least one order of magnitude lower intracellular nanocrystals than previously reported. Their long‐term photostability enables to investigate quantitatively at the single cell level their cellular fate in hematopoietic stem cells (HSCs) using both multiphoton and electron microscopy. It is found that the concentration of nanocrystals in proliferative multipotent progenitors is over 2.5‐fold greater compared to quiescent stem cells; this difference vanishes when HSCs enter a nonquiescent, proliferative state, while their potency remains unaffected. Understanding the nanoparticle stem cell interaction allows to establish an effective and safe nanoparticle labeling strategy into somatic stem cells that can critically contribute to an understanding of their in vivo therapeutic potential.

Sugiyama, Nami↗

A Graded, Porous Composite of Natural Biopolymers and Octacalcium Phosphate Guides Osteochondral Differentiation of Stem Cells

Abstract Lesions involving the osteochondral unit are difficult to treat. Biomimetic scaffolds are previously shown as promising alternative. Such devices often lack multiple functional layers that mimic bone, cartilage, and the interface. In this study, multilayered scaffolds are developed based on the use of natural extracellular matrix (ECM)‐like biopolymers. Particular attention is paid to obtain a complex matrix that mimics the native osteochondral transition. Porous, sponge‐like chitosan‐collagen‐octacalcium phosphate (OCP) scaffolds are obtained. Collagen content increases while the amount of OCP particles decreases toward the cartilage layer. The scaffolds are bioactive as a mineral layer is deposited containing hydroxyapatite at the bony side. The scaffolds stimulate proliferation of human adipose‐derived mesenchymal stem cells, but the degree of proliferation depends on the cell seeding density. The scaffolds give rise to a zone‐specific gene expression. RUNX2, COL1A1, BGLAP, and SPP1 are upregulated in the bony layer of the scaffold. SOX9 is upregulated concomitant with COL2A1 expression in the cartilage zone. Mineralization in presence of the cells is prominent in the bone area with Ca and P steadily increasing over time. These results are encouraging for the fabrication of biomimetic scaffolds using ECM‐like materials and featuring gradients that mimic native tissues and their interface.

Amann, Elisabeth↗

Extracellular matrix protein DMP1 suppresses osteogenic differentiation of Mesenchymal Stem Cells

Highlights: • Extracellular matrix protein DMP1 suppresses MSCs osteogenic differentiation. • DMP1 works not only in osteoblasts and osteocytes, but also in MSCs. Mesenchymal Stem Cells (MSCs) are self-renewing and multipotent stem cells which was investigated for diverse clinical applications. However, complex mechanism of MSCs fate determination is still not fully disclosed. Extracellular matrix (ECM) proteins contribute to maintain MSCs stemness by providing extracellular microenvironment. Increasing evidences show that ECM proteins could also regulate the fate of MSCs directly. Dentin matrix protein 1 (DMP1) is an ECM protein enrich in bone tissue and terminal cells, which well-known in promoting osteoblasts and osteocytes maturation, and facilitate mineralization. Recently, our experiment indicated that DMP1 was also expressed in MSCs of long bone. In present study, it is found that DMP1 expressed in Prx1 positive MSCs. And, DMP1 is down-regulated in early osteoblasts and up-regulated again in mature osteoblasts. DMP1 conditional knockout mice model under Prx1cre was generated to explore whether DMP1 regulates MSCs osteogenic differentiation. Specific ablation of DMP1 in Prx1 positive MSCs increased bone mass in vivo and promoted osteoblasts activity in vitro. This study provides a new understanding of DMP1's function in regulation of osteogenesis: not only an enhancer of bone formation, but also a negative regulator of MSCs differentiation in bone.

60 APPLIED LIFE SCIENCES↗

MicroRNA-374b promotes the proliferation and differentiation of neural stem cells through targeting Hes1

Highlights: • miR-374b expression was upregulated during NSC differentiation. • miR-374b promoted NSC proliferation and differentiation to neurons. • Hes1 was identified as a target gene of miR-374b. • miR-374b regulated NSC proliferation and differentiation by Hes1 Accumulating evidence has documented that microRNAs (miRNAs) are critical regulators of neural stem cell (NSC) proliferation and differentiation. MiRNA-374b (miR-374b) has been reported to play an important role in regulating various cellular processes, such as proliferation and differentiation. However, whether miR-374b is involved in NSC proliferation and differentiation remains unclear. In this study, we investigated the potential role of miR-374b in regulating NSC proliferation and differentiation to elucidate the underlying molecular mechanism. Our results showed that miR-374b expression was significantly upregulated during NSC differentiation. Functional experiments showed that overexpression of miR-374b promoted NSC proliferation and differentiation to neurons. By contrast, miR-374b inhibition showed the opposite effect. Hairy and enhancer of split 1 (Hes1), a master regulator of neurogenesis, was predicted as a potential target gene of miR-374b by bioinformatics analysis. Dual-luciferase reporter assays showed that miR-374b could directly target the 3′-untranslated region of Hes1. Further experiments showed that miR-374b negatively regulated the mRNA and protein expression of Hes1 in NSCs. Moreover, overexpression of Hes1 significantly reversed the miR-374b overexpression-mediated effect on NSC proliferation and differentiation. In addition, knockdown of Hes1 abrogated the miR-374b inhibition-mediated effect on NSC proliferation and differentiation. Taken together, these results demonstrate that miR-374b regulates the proliferation and differentiation of NSCs through targeting Hes1 and suggest that miR-374b is a potential target for modulating NSC-mediated neurogenesis.

60 APPLIED LIFE SCIENCES↗

The transcription factor MEF2A plays a key role in the differentiation/maturation of rat neural stem cells into neurons

Highlights: • Undifferentiated and differentiated neural stem cells (NSCs) express MEF2A in vitro. • NSC-derived neurons express more MEF2A than NSC-derived glia. • Ablating MEF2A reduces NSC differentiation into neurons. Neural stem cells (NSCs) are self-renewing multipotent stem cells that can be proliferated in vitro and differentiated into neuronal and/or glial lineages, making them an ideal model to study the processes involved in neuronal differentiation. Here we have used NSCs to investigate the role of the transcription factor MEF2A in neuronal differentiation and development in vitro. We show that although MEF2A is present in undifferentiated NSCs, following differentiation it is expressed at significantly higher levels in a subset of neuronal compared to non-neuronal cells. Furthermore, shRNA-mediated knockdown of MEF2A reduces the number of NSC-derived neurons compared to non-neuronal cells after differentiation. Together, these data indicate that MEF2A participates in neuronal differentiation/maturation from NSCs.

60 APPLIED LIFE SCIENCES↗

Identification and Optimization of Novel Small c-Abl Kinase Activators Using Fragment and HTS Methodologies

Abelson kinase (c-Abl) is a ubiquitously expressed, nonreceptor tyrosine kinase which plays a key role in cell differentiation and survival. It was hypothesized that transient activation of c-Abl kinase via displacement of the N-terminal autoinhibitory “myristoyl latch”, may lead to an increased hematopoietic stem cell differentiation. This would increase the numbers of circulating neutrophils and thus be an effective treatment for chemotherapy-induced neutropenia. This paper describes the discovery and optimization of a thiazole series of novel small molecule c-Abl activators, initially identified by a high throughput screening. Subsequently, a scaffold-hop, which exploited the improved physicochemical properties of a dihydropyrazole analogue, identified through fragment screening, delivered potent, soluble, cell-active c-Abl activators, which demonstrated the intracellular activation of c-Abl in vivo.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

CBFA2T2 is required for BMP-2-induced osteogenic differentiation of mesenchymal stem cells

Highlights: • CBFA2T2 expression was upregulated by BMP-2 treatment during osteogenesis of MSCs. • Knockdown of CBFA2T2 blunted the BMP-2-induced osteogenic differentiation of MSCs. • Knockdown of CBFA2T2 promoted expression of EHMT1 in BMP-2-treated mBMSCs. • Knockdown of CBFA2T2 increased H3K9me2 levels at promoter of Runx2. Bone morphogenetic protein (BMP) signaling is one of the essential pathways involved in osteogenic differentiation of mesenchymal stem cells (MSCs) and regulation of bone formation. While BMP-2 has been approved for clinic use, the underlying mechanisms remain not fully understood. In this study, we found co-repressor CBFA2T2 (core-binding factor, runt domain, alpha subunit 2, translocated to, 2) expression was significantly upregulated in response to BMP-2 treatment during osteogenic differentiation of human dental pulp stem cells (hDPSCs) and mouse bone marrow stromal cells (mBMSCs). siRNA-mediated knockdown of CBFA2T2 blunted the BMP-2-induced allkaline phosphatase (ALP) activity, mineralization of extracelluar matrix (ECM), and expression of osteogenic related genes in both hDPSCs and mBMSCs. Mechanistically, knockdown of CBFA2T2 promoted expression of euchromatic histone methyltransferase 1 (EHMT1) in mBMSCs, which further led to upregulation of H3K9me2 levels at promoter of runt related transcription factor 2 (Runx2), the master regulator of osteogenesis. Collectively, our findings indicate that CBFA2T2 is required for BMP-2-induced osteogenic differentiation of MSCs through inhibition of EHMT1-mediated histone methylation at Runx2 promoter.

60 APPLIED LIFE SCIENCES↗

An oscillatory network controlling self-renewal of skeletal muscle stem cells

The balance between proliferation and differentiation of muscle stem cells is tightly controlled, ensuring the maintenance of a cellular pool needed for muscle growth and repair. Muscle stem cells can proliferate, they can generate differentiating cells, or they self-renew to produce new stem cells. Notch signaling plays a crucial role in this process. Recent studies revealed that expression of the Notch effector HES1 oscillates in activated muscle stem cells. The oscillatory expression of HES1 periodically represses transcription from the genes encoding the myogenic transcription factor MYOD and the Notch ligand DLL1, thereby driving MYOD and DLL1 oscillations. This oscillatory network allows muscle progenitor cells and activated muscle stem cells to remain in a proliferative and ‘undecided’ state, in which they can either differentiate or self-renew. When HES1 is downregulated, MYOD oscillations become unstable and are replaced by sustained expression, which drives the cells into terminal differentiation. During development and regeneration, proliferating stem cells contact each other and the stability of the oscillatory expression depends on regular DLL1 inputs provided by neighboring cells. In such communities of cells that receive and provide Notch signals, the appropriate timing of DLL1 inputs is important, as sustained DLL1 cannot replace oscillatory DLL1. Thus, in cell communities, DLL1 oscillations ensure the appropriate balance between self-renewal and differentiation. In summary, oscillations in myogenic cells are an important example of dynamic gene expression determining cell fate.

60 APPLIED LIFE SCIENCES↗

Assessment of the hepatocytic differentiation ability of human skin-derived ABCB5+ stem cells

Highlights: • Stem cell-derived hepatocytes may be used for cell therapy of liver diseases. • ABCB5-positive stem cell feature characteristics of mesenchymal stromal cells. • Hepatocytic differentiation of ABCB5{sup +} stem cells is incomplete. • However, they secrete hepatotropic factors that may support liver regeneration. • Hepatic delivery of the cells does not cause obvious adverse effects in the mouse. The continuously decreasing willingness for liver donation aggravates treatment of end-stage liver diseases requiring organ transplantation as the only curative strategy. Cell therapy approaches using human hepatocytes or stem cell-derived hepatocyte-like cells may be a therapeutic option out of this dilemma. ABCB5-positive mesenchymal stromal cells from human skin featured promising potential to treat immune-mediated diseases. Since most of chronic liver diseases involve exaggerating immune mechanisms, it was the aim to demonstrate in this study, whether ABCB5{sup +} stem cells may serve as a resource to generate hepatocytic cells for application in liver cell transplantation. Using an established single-step protocol, which had been successfully applied to differentiate mesenchymal stromal cells into the hepatocytic lineage, ABCB5{sup +} skin-derived stem cells did not gain significant characteristics of hepatocytes. Yet, upon culture in hepatocytic differentiation medium, ABCB5{sup +} stem cells secreted immunomodulatory and anti-fibrotic factors as well as proteins, which may prompt hepatic morphogenesis besides others. Hepatic transplantation of ABCB5{sup +} stem cells, which had been prior cultured in hepatocytic differentiation medium, did not cause any obvious deterioration of liver architecture suggesting their safe application. Thus, human ABCB5{sup +} skin-derived stem cells secreted putative hepatotropic factors after culture in hepatocytic differentiation medium.

60 APPLIED LIFE SCIENCES↗

NIR Biosensing of Neurotransmitters in Stem Cell‐Derived Neural Interface Using Advanced Core–Shell Upconversion Nanoparticles

Abstract Nondestructive neurotransmitter detection and real‐time monitoring of stem cell differentiation are both of great significance in the field of neurodegenerative disease and regenerative medicine. Although luminescent biosensing nanoprobes have been developed to address this need, they have intrinsic limitations such as autofluorescence, scattering, and phototoxicity. Upconversion nanoparticles (UCNPs) have gained increasing attention for various biomedical applications due to their high photostability, low auto‐fluorescent background, and deep tissue penetration; however, UCNPs also suffer from low emission intensities due to undesirable energy migration pathways. To address the aforementioned issue, a single‐crystal core–shell–shell “sandwich” structured UCNP is developed that is designed to minimize deleterious energy back‐transfer to yield bright visible emissions using low power density excitations. These UCNPs show a remarkable enhancement of luminescent output relative to conventional β‐NaYF4:Yb,Er codoped UCNPs and β‐NaYF4:Yb,Er@NaYF4:Yb “active shell” alike. Moreover, this advanced core–shell–shell UCNP is subsequently used to develop a highly sensitive biosensor for the ultrasensitive detection of dopamine released from stem cell‐derived dopaminergic‐neurons. Given the challenges of in situ detection of neurotransmitters, the developed NIR‐based biosensing of neurotransmitters in stem cell‐derived neural interfaces present a unique tool for investigating single‐cell mechanisms associated with dopamine, or other neurotransmitters, and their roles in neurological processes.

Rabie, Hudifah↗

Aging impairs beige adipocyte differentiation of mesenchymal stem cells via the reduced expression of Sirtuin 1

Highlights: • Aging impaired beige adipocyte differentiation of AT-MSC by induction of senescence. • The induced senescence in elderly AT-MSC caused by reduction of Sirt1 and Sirt3. • Sirt1 activated beige adipocyte differentiation of elderly AT-MSC via p53/p21 pathway. In the body, different types of adipose tissue perform different functions, with brown and beige adipose tissues playing unique roles in dissipating energy. Throughout life, adipocytes are regenerated from progenitors, and this process is impaired by aging. One of the progenitors of adipocytes are mesenchymal stem cells (MSCs), which have recently become a promising tool for stem cell therapy. However, whether or not aging impairs the brown/beige adipocyte differentiation of adipose tissue-derived MSCs (AT-MSCs) remains unclear. In the present study, we isolated AT-MSCs from two different age groups of donors (infants and elderly subjects) and examined the effects of aging on the AT-MSC brown/beige adipocyte differentiation ability. We found that none of the AT-MSCs expressed Myf5, which indicated the beige (not brown) differentiation ability of cells. Of note, an inverse correlation was noted between the beige adipocyte differentiation ability and age, with AT-MSCs derived from elderly donors showed the most severely reduced function due to induced cellular senescence. The impaired expression of Sirtuin 1 (Sirt1) and Sirt3 proved to be responsible for the induction of senescence in elderly AT-MSCs; however, only Sirt1 was directly involved in the regulation of beige adipocyte differentiation. The overexpression of Sirt1 impaired the p53/p21 pathway, thereby preventing elderly AT-MSCs from entering senescence and restoring the beige differentiation ability. Thus, our study represents the important role of Sirt1 and senescence in the regulation of beige adipocyte differentiation during aging.

60 APPLIED LIFE SCIENCES↗

Identification of functional non-coding variants associated with orofacial cleft

Oral facial cleft (OFC) comprises cleft lip with or without cleft palate (CL/P) or cleft palate only. Genome wide association studies (GWAS) of isolated OFC have identified common single nucleotide polymorphisms (SNPs) in many genomic loci where the presumed effector gene (for example, IRF6 in the 1q32 locus) is expressed in embryonic oral epithelium. To identify candidates for functional SNPs at eight such loci we conduct a massively parallel reporter assay in a fetal oral epithelial cell line, revealing SNPs with allele-specific effects on enhancer activity. We filter these SNPs against chromatin-mark evidence of enhancers and test a subset in traditional reporter assays, which support the candidacy of SNPs at loci containing FOXE1, IRF6, MAFB, TFAP2A, and TP63. For two SNPs near IRF6 and one near FOXE1, we engineer the genome of induced pluripotent stem cells, differentiate the cells into embryonic oral epithelium, and discover allele-specific effects on the levels of effector gene expression, and, in two cases, the binding affinity of transcription factors FOXE1 or ETS2. Conditional analyses of GWAS data suggest the two functional SNPs near IRF6 account for the majority of risk for CL/P at this locus. This study connects genetic variation associated with OFC to mechanisms of pathogenesis.

Kumari, Priyanka↗