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Recent studies have found discordant mechanosensitive outcomes when comparing 2D and 3D, highlighting the need for tools to study mechanotransduction in 3D across a wide spectrum of stiffness. A gelatin methacryloyl (GelMA) hydrogel with a continuous stiffness gradient ranging from 5 to 38 kPa was developed to recapitulate physiological stiffness conditions. Adipose-derived stem cells (ASCs) were encapsulated in this hydrogel, and their morphological characteristics and expression of both mechanosensitive proteins (Lamin A, YAP, and MRTFa) and differentiation markers (PPARγ and RUNX2) were analyzed. Low-stiffness regions (∼8 kPa) permitted increased cellular and nuclear volume and enhanced mechanosensitive protein localization in the nucleus. This trend was reversed in high stiffness regions (∼30 kPa), where decreased cellular and nuclear volumes and reduced mechanosensitive protein nuclear localization were observed. Interestingly, cells in soft regions exhibited enhanced osteogenic RUNX2 expression, while those in stiff regions upregulated the adipogenic regulator PPARγ, suggesting that volume, not substrate stiffness, is sufficient to drive 3D stem cell differentiation. Inhibition of myosin II (Blebbistatin) and ROCK (Y-27632), both key drivers of actomyosin contractility, resulted in reduced cell volume, especially in low-stiffness regions, causing a decorrelation between volume expansion and mechanosensitive protein localization. Constitutively active and inactive forms of the canonical downstream mechanotransduction effector TAZ were stably transfected into ASCs. Activated TAZ resulted in higher cellular volume despite increasing stiffness and a consistent, stiffness-independent translocation of YAP and MRTFa into the nucleus. Thus, volume adaptation as a function of 3D matrix stiffness can control stem cell mechanotransduction and differentiation.

Identifying molecular and cellular processes that regulate reprogramming competence of transcription factors broadens our understanding of reprogramming mechanisms. In the present study, by a chemical screen targeting major epigenetic pathways in human reprogramming, we discovered that inhibiting specific epigenetic roadblocks including disruptor of telomeric silencing 1-like (DOT1L)-mediated H3K79/K27 methylation, but also other epigenetic pathways, catalyzed by lysine-specific histone demethylase 1A, DNA methyltransferases and histone deacetylases, allows induced pluripotent stem cell generation with almost all OCT factors. We found that simultaneous inhibition of these pathways not only dramatically enhances reprogramming competence of most OCT factors, but in fact enables dismantling of species-dependent reprogramming competence of OCT6, NR5A1, NR5A2, TET1 and GATA3. Harnessing these induced permissive epigenetic states, we performed an additional screen with 98 candidate genes. Thereby, we identified 25 transcriptional regulators (OTX2, SIX3, and so on) that can functionally replace OCT4 in inducing pluripotency. Our findings provide a conceptual framework for understanding how transcription factors elicit reprogramming in dependency of the donor cell epigenome that differs across species. A chemical screen targeting major epigenetic pathways identifies permissive epigenetic states that enable reprogramming with a broad range of transcriptional regulators and almost all octamer-binding (OCT) family members.

From senescence and frailty that may result from various biological, mechanical, nutritional, and metabolic processes, the human body has its own antioxidant defense enzymes to remove by-products of oxygen metabolism, and if unregulated, can cause several types of cell damage. Herein, an antioxidant, artificial nanoscale enzyme, called nanozyme (NZs), is introduced that is composed of Au nanoparticles (NPs) synthesized with a mixture of two representative phytochemicals, namely, gallic acid (GA) and isoflavone (IF), referred to as GI-Au NZs. Their unique antioxidant and anti-aging effects are monitored using Cell Counting Kit-8 and senescence-associated β-galactosidase assays on neonatal human dermal fibroblasts (nHDFs). Furthermore, alterations in epidermal thickness and SOD activity are measured under ultraviolet light to investigate the effects of the topical application of NZs on the histological structure and antioxidant activity in hairless mice skin. Then, hepatotoxicity and nephrotoxicity in the hairless mice are monitored. It is concluded that the NZs can effectively prevent serial passage-induced senescence in nHDFs, as well as oxidative stress in mice skin, suggesting a range of strategies to further develop novel therapeutics for acute frailty.

Background and Objectives: Recent studies have described direct reprogramming of mouse and human somatic cells into induced neural stem cells (iNSCs) using various combinations of transcription factors. Although iNSC technology holds a great potential for clinical applications, the low conversion efficiency and limited reproducibility of iNSC generation hinder its further translation into the clinic, strongly suggesting the necessity of highly reproducible method for human iNSCs (hiNSCs). Thus, in orderto develop a highly efficient and reproducible protocol for hiNSC generation, we revisited the reprogramming potentials of previously reported hiNSC reprogramming cocktails by comparing the reprogramming efficiency of distinct factor combinations including ours.Methods: We introduced distinct factor combinations, OSKM (OCT4+SOX2+KLF4+C-MYC), OCT4 alone, SOX2 alone, SOX2+HMGA2, BRN4+SKM+SV40LT (BSKMLT), SKLT, SMLT, and SKMLT and performed comparative analysis of reprogramming potentials of distinct factor combinations in hiNSC generation.Results: Here we show that ectopic expression of five reprogramming factors, BSKMLT leads the robust hiNSC generation (>80 folds enhanced efficiency) from human somatic cells compared with previously described factor combinations. With our combination, we were able to observe hiNSC conversion within 7 days of transduction. Throughout further optimization steps, we found that both BRN4 and KLF4 are not essential for hiNSC conversion.Conclusions: Our factor combination could robustly and reproducibly generate hiNSCs from human somatic cells with distinct origins. Therefore, our novel reprogramming strategy might serve as a useful tool for hiNSC-based clinical application.

A polyphenolic extract from melon (Cucumis melo L.), as a potential source of natural antioxidants, has been reported to have a positive effect on osteoblast activity. In this study, the protective effects of heat-treated melon extract (ECO-A) on bone strength, mineralization, and metabolism were examined in osteoporotic rat models. Osteoporosis was induced by ovariectomy (OVX) in female rats and then maintained for 8 weeks, along with the ingestion of phosphate-buffered saline (PBS, OVXP) or ECO-A (OVXE) for an additional 4 weeks. At a pre-determined timepoint, bone strengths, as well as bone mineral contents (BMC) and the density (BMD) of femurs and/or lumbar spines extracted from each animal, were measured by a mechanical test and dual-energy X-ray absorptiometry, respectively. Moreover, several biochemical markers for bone turnover were analyzed by respective colorimetric assay kits in addition to clinical analyses. The maximum load and stiffness of femurs from the OVXE group were found to be significantly higher than the other groups. Furthermore, the OVXE group showed significantly higher BMC, BMD, and bone volume than the OVX and OVXP groups, which were comparable to the non-OVX (sham) group. The levels of bone formation and resorption markers in the OVXE group were similar to the sham group, but significantly different from other groups. In conclusion, these results suggest that ECO-A can play potentially positive roles in the protection of bone loss in rats with OVX-induced osteoporosis.

Simultaneous expression of Oct4, Klf4, Sox2, and cMyc induces pluripotency in somatic cells (iPSCs). Replacing Oct4 with the neuro-specific factor Brn4 leads to transdifferentiation of fibroblasts into induced neural stem cells (iNSCs). However, Brn4 was recently found to induce transient acquisition of pluripotency before establishing the neural fate. We employed genetic lineage tracing and found that induction of iNSCs with individual vectors leads to direct lineage conversion. In contrast, polycistronic expression produces a Brn4-Klf4 fusion protein that enables induction of pluripotency. Our study demonstrates that a combination of pluripotency and tissue-specific factors allows direct somatic cell transdifferentiation, bypassing the acquisition of a pluripotent state. This result has major implications for lineage conversion technologies, which hold potential for providing a safer alternative to iPSCs for clinical application both in vitro and in vivo.

Summary Generation of induced oligodendrocyte progenitor cells (iOPCs) from somatic fibroblasts is a strategy for cell-based therapy of myelin diseases. However, iOPC generation is inefficient, and the resulting iOPCs exhibit limited expansion and differentiation competence. Here we overcome these limitations by transducing an optimized transcription factor combination into a permissive donor phenotype, the pericyte. Pericyte-derived iOPCs (PC-iOPCs) are stably expandable and functionally myelinogenic with high differentiation competence. Unexpectedly, however, we found that PC-iOPCs are metastable so that they can produce myelination-competent oligodendrocytes or revert to their original identity in a context-dependent fashion. Phenotypic reversion of PC-iOPCs is tightly linked to memory of their original transcriptome and epigenome. Phenotypic reversion can be disconnected from this donor cell memory effect, and in vivo myelination can eventually be achieved by transplantation of O4+ pre-oligodendrocytes. Our data show that donor cell source and memory can contribute to the fate and stability of directly converted cells.

Low dimensional nanomaterials (LDNMs) have earned attention among researchers as they exhibit a larger surface area to volume and quantum confinement effect compared to high dimensional nanomaterials. LDNMs, including 0-D and 1-D, possess several beneficial biomedical properties such as bioimaging, sensor, cosmetic, drug delivery, and cancer tumors ablation. However, they threaten human beings with the adverse effects of cytotoxicity, carcinogenicity, and genotoxicity when exposed for a prolonged time in industry or laboratory. Among different toxicities, genotoxicity must be taken into consideration with utmost importance as they inherit DNA related disorders causing congenital disabilities and malignancy to human beings. Many researchers have performed NMs' genotoxicity using various cell lines and animal models and reported the effect on various physicochemical and biological factors. In the present work, we have compiled a comparative study on the genotoxicity of the same or different kinds of NMs. Notwithstanding, we have included the classification of genotoxicity, mechanism, assessment, and affecting factors. Further, we have highlighted the importance of studying the genotoxicity of LDNMs and signified the perceptions, future challenges, and possible directives in the field.

The design of multifunctional agents became a pivotal task for the development of personalized medicine. In this study, we investigated the potential applicability of mesoporous silica decorated with gold nanoparticles (MS-Au NPs) for effective X-ray attenuation in computed tomography (CT) and as a potential vehicle for drug delivery. The physicochemical properties and X-ray attenuation efficiency of prepared MS-Au NPs were systematically studied using a range of characterization techniques and clinical CT correspondingly. CT analysis revealed that prepared MS-Au NPs exhibit high X-ray attenuation efficiency ∼ 9.8 HU/mM (Hounsfield Units per mM of Au) as compared to other perspective metal-based nanoparticles reported in the literature. An improved X-ray attenuation efficiency can be attributed to the presence of a large amount of Au nanoparticles in a confined volume unit.

Rare-earth metal oxide nanoparticles considered promising contrast agents for x-ray computed tomography (CT) and magnetic resonance imaging (MRI). The main purpose of this study is to investigate the potential applicability of polyethyleneimine (PEI)-coated Eu2O3 and Dy2O3 nanoparticles (NPs) for CT x-ray attenuation. Morphology and other physicochemical properties of prepared samples were systematically investigated using a range of characterization tools. Preliminary cytotoxicity experiments with L-929 fibroblastic cells suggested that both samples have no significant toxicity at concentrations below 100 μg ml−1. Clinical CT analysis shows that PEI@Eu2O3 NPs exhibit higher x-ray attenuation efficiency (∼8 HU mM−1) as compared to PEI@Dy2O3 NPs (∼5 HU mM−1).

Here, we describe the striking irreversible volume expansion of micron-sized Sn anodes for lithium rechargeable batteries during cycling with brand-new Sn islands that are prepared by electrodeposition on a Cu substrate. Exceptional changes in the internal as well as external microstructure of the electrodeposited Sn islands are demonstrated by ex situ morphological analyses. The cross sectional micrographs of the Sn islands prove the widespread formation of nano-voids within individual Sn islands after initial Li dealloying followed by their enrichment during the subsequent cycles. These widespread voids and the following dead volume formed inside the Sn islands induce irreversible volume expansion in the micron-sized Sn anodes, thereby deteriorating the cycling performance of the Sn anodes.

The purpose of this study was to describe a novel bone lengthening plate (BLP) and to evaluate the biomechanical performance of the plate before clinical use. A finite element model was obtained from values of the compression test. It was used to evaluate the performance of the BLP, such as biomechanical stability and structural stiffness, according to materials of the shaft and column used for lengthening (type I: all Titanium-alloys, type II and III: Titanium-alloys and Cobalt-Chrome-alloys, type IV: all Cobalt-Chrome-alloys). Furthermore, Peak von Mises Stress, risk of screw breakage, and micro-motion between the bone and screw were evaluated. Structural stiffness and strain of the finite element model of the femur were similar to cadaveric femurs. Structural stiffness increased from type I (Titanium alloys) to type IV (Cobalt-Chrome-alloys) by at least 128%. First locking screw, which was inserted at the osteotomy site of the proximal femur (proximal to distal direction), showed the highest risk of breakage (75%). This study investigated biomechanical stability of the novel BLP in relation to properties of the supporting structures. It was most biomechanically stable when the column and lengthening shaft were composed of Cobalt-Chrome-alloys (type IV).

Aquaporin-3 (AQP3) is an integral membrane protein that facilitates the transport of water and glycerol across cell membranes. However, the precise localization and function of AQP3 in skeletal muscles is currently unknown. In this study, we investigated the capacity of AQP3 knockout mice to perform a single bout of exhausting exercise and analyzed the parameters related to skeletal muscle energy metabolism during exhausting exercise. Mice were exposed to a single bout of treadmill running at a speed of 12 m/min with 10° inclination until exhaustion, and sacrificed immediately, 24 h and 48 h after exercise. Both immunohistochemistry and double immunofluorescence staining revealed that AQP3 is expressed at the cell surface with no evidence of colocalization with either AQP1 or AQP4 in hamstring skeletal muscles. When exposed to a single bout of exhaustive exercise, AQP3 knockout mice fatigued more easily with the average time to exhaustion shorter than the wild-type mice. After exhausting exercise, plasma glucose, muscle glycogen, muscle triglyceride, and muscle free fatty acid levels decreased compared with the values before exercise in both AQP3 knockout and wild-type mice. However, muscle glycerol concentration after exercise decreased in the wild-type mice, but rather increased in AQP3 knockout mice. These findings suggest that decreased glycerol efflux from the skeletal muscles in AQP3 knockout mice may result in low exercise capacity, presumably due to the limitations in the constant energy supply through hepatic gluconeogenesis from glycerol during the prolonged endurance exercise.

The polarization of the Golgi apparatus is an important phenomenon in the directional migration of many types of cells, including fluid shear stress enhanced infiltration of cells into scaffolds. Fourier transform infrared (FT-IR) spectroscopy would be a potential tool to study cell infiltration into scaffolds because this technique has simple, reproducible, non-destructive characteristics. Here, we investigated the effect of Golgi polarization on the directional migration and infiltration of human mesenchymal stem cells (hMSCs) into poly(lactic-co-glycolic acid) (PLGA) scaffolds by fluid shear stress. The cell infiltration into scaffolds by fluid shear stress was observed by immunofluorescence and FT-IR. 2 μM of Brefeldin A (BFA) inhibited the reorganization of Golgi polarization in hMSCs. The blocking of Golgi reorganization by BFA caused the suppression of directional migration and infiltration into PLGA scaffolds induced by 8 dyne/cm2 of fluid shear stress condition. In this study, we investig...

SummaryRecent studies have shown that defined factors could lead to the direct conversion of fibroblasts into induced hepatocyte-like cells (iHeps). However, reported conversion efficiencies are very low, and the underlying mechanism of the direct hepatic reprogramming is largely unknown. Here, we report that direct conversion into iHeps is a stepwise transition involving the erasure of somatic memory, mesenchymal-to-epithelial transition, and induction of hepatic cell fate in a sequential manner. Through screening for additional factors that could potentially enhance the conversion kinetics, we have found that c-Myc and Klf4 (CK) dramatically accelerate conversion kinetics, resulting in remarkably improved iHep generation. Furthermore, we identified small molecules that could lead to the robust generation of iHeps without CK. Finally, we show that Hnf1α supported by small molecules is sufficient to efficiently induce direct hepatic reprogramming. This approach might help to fully elucidate the direct conversion process and also facilitate the translation of iHep into the clinic.

Guided bone regeneration (GBR) is a technique where a barrier membrane is placed over the bone defect to prevent cell growth from the connective tissue and epithelium. Titanium (Ti) has excellent mechanical properties and is one of the most frequently used materials in implant dentistry. This study examined how graphene oxide (GO)-coated Ti (GO-Ti) membranes can enhance the osteogenesis of MC3T3-E1 preosteoblasts and promote new bone formation for potential applications to GBR. The physicochemical properties of GO-Ti membranes were characterized by atomic force microscopy, Raman spectroscopy, X-ray diffraction, and contact angle measurements. The cellular behaviors of MC3T3-E1 preosteoblasts on GO-Ti membranes were examined by cell counting kit-8 and alkaline phosphatase (ALP) activity assays. The effects of GO-Ti membranes on bone regeneration were evaluated by implanting them into rat calvarial defects. GO was coated uniformly on Ti substrates, which allowed a decrease in surface roughness and c...

Recently, numerous studies have focused on the development of scaffolds for skeletal tissue engineering and regeneration with various structures. Among various structures, in situ forming hydrogels have attracted considerable attention because they can provide 3D microenvironments for cells, and their stiffness and elasticity can be easily controlled by physical or chemical means. Over the last decade, graphene oxide (GO) has been widely explored as a potential candidate for biomaterials because of its excellent physicochemical properties and outstanding biocompatibility. In this study, horseradish peroxide-reactive gelatin polymer (GH) hydrogels incorporated with GO were prepared and their physicochemical and biomechanical properties were characterized by scanning electron microscopy, Raman and Fourier transform-infrared spectroscopy, ther-mogravimetric analysis, and rheological study. The cellular behaviors of the C2C12 myoblasts within the GO-incorporated GH (GH/GO) hydrogels were examined by a...

Spermatogonial stem cells (SSCs), which are unipotent stem cells in the testes that give rise to sperm, can be converted into germline-derived pluripotent stem (gPS) by self-induction. The androgenetic imprinting pattern of SSCs is maintained even after their reprogramming into gPS cells. In this study, we used an in vitro neural differentiation model to investigate whether the imprinting patterns are maintained or altered during differentiation. The androgenetic patterns of H19, Snrpn, and Mest were maintained even after differentiation of gPS cells into NSCs (gPS-NSCs), whereas the fully unmethylated status of Ndn in SSCs was altered to somatic patterns in gPS cells and gPS-NSCs. Thus, our study demonstrates epigenetic alteration of genomic imprinting during the induction of pluripotency in SSCs and neural differentiation, suggesting that gPS-NSCs can be a useful model to study the roles of imprinted genes in brain development and human neurodevelopmental disorders.

Somatic cells could be directly converted into induced neural stem cells (iNSCs) by ectopic expression of defined transcription factors. However, the underlying mechanism of direct lineage transition into iNSCs is largely unknown. In this study, we examined the effect of genetic background on the direct conversion process into an iNSC state. The iNSCs from two different mouse strains exhibited the distinct efficiency of lineage conversion as well as clonal expansion. Furthermore, the expression levels of endogenous NSC markers, silencing of transgenes, and in vitro differentiation potential were also different between iNSC lines from different strains. Therefore, our data suggest that the genetic background of starting cells influences the conversion efficiency as well as reprogramming status of directly converted iNSCs.

Mechanical testing based on ISO 14801 standard is generally used to evaluate the performance of the dental implant system according to material and design changes. However, the test method is difficult to reflect on the clinical environment because the ISO 14801 standard does not take into account the various loads from different directions during chewing motion. In addition, the fracture pattern of the implant system can occur both in the horizontal and the vertical directions. Therefore, the purpose of this study was to compare fatigue characteristics and fracture patterns between single directional loading conditions based on the ISO 14801 standard and multi-directional loading condition. Firstly, the static test was performed on five specimens to derive the fatigue load, and the fatigue load was chosen as 40% of the maximum load measured in the static test. Subsequently, the fatigue test was performed considering the single axial/occlusal (AO), AO with facial/lingual (AOFL) and AO with mesial/distal (AOMD) directions, and five specimens were used for each fatigue loading modes. In order to analyze the fatigue characteristics, the fatigue cycle at the time of specimen fracture and displacement change of the specimen every 500 cycles were measured. Field emission scanning electron microscopy (FE-SEM) was used to analyze the fracture patterns and the fracture surface. Compared to the AO group, the fatigue cycle of the AOFL and AOMD groups showed lower about five times, while the displacement gradually increased with every 500 cycles. From FE-SEM results, there were no different surface morphology characteristics among three groups. However, the AOMD group showed a vertical slip band. Therefore, our results suggest that the multi-directional loading mode under the worst-case environment can reproduce the vertical fracture pattern in the clinical situation and may be essential to reflect on the dental implant design including connection types and surface treatments.

In this study, fluorescent carbon nanoparticles (CNPs) with quantum yield of 6.08% have been synthesized using a hydrothermal method within a short period of time (t = 30 min). Fluorescence spectroscopy (FS) revealed that CNPs demonstrate excellent photostability which is suitable for prolonged bioimaging applications. Cytotoxicity study with L-929 fibroblastic cells showed that prepared CNPs are nontoxic even at relatively high concentrations up to 250 µg/ml. Strong green fluorescence signal observed from L-929 cells suggested that CNPs can be utilized for in-vitro tissues/cells bioimaging applications.

Cordyceps militaris is a commonly used medicinal mushroom containing various therapeutic effects such as anti-inflammatory, anti-allergic, and anti-cancer activities. This study examined whether Cordyceps militaris on germinated soybeans (GSC) has a suppressive effect on a v-ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS)-driven colorectal cancer which is notorious for its un-druggable features and the ineffectiveness of conventional therapies against it. GSC extract was prepared and its proximate composition and amino acids were analyzed. The suppressive effects were investigated with the KRAS-driven colorectal cancer cell-line, SW480. SW480 proliferation, clonogenic potential, apoptosis, and the RAS/extracellular signal-regulated kinase (ERK) pathway under the GSC treatment were analyzed by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay, flow cytometry, and Western blot, respectively. An in vivo experiment with the SW480 xenograft mouse model was performed. As a result, GSC suppressed cell proliferation by inducing the apoptosis of KRAS-driven colorectal cancer cells and inhibited clonogenic capabilities. The decrease of KRAS and ERK phosphorylation was detected by Western blot. Tumor growth was significantly suppressed when GSC was introduced to the tumor-xenograft mouse model. In conclusion, GSC suppressed KRAS-driven colorectal cancer growth both in vitro and in vivo, and can be used as an alternative or simultaneous approach in colorectal cancer therapy.

Graphene is a two-dimensional atomic layer of graphite, where carbon atoms are assembled in a honeycombed lattice structure. Recently, graphene family nanomaterials, including pristine graphene, graphene oxide and reduced graphene oxide, have increasingly attracted a great deal of interest from researchers in a variety of science, engineering and industrial fields because of their unique structural and functional features. In particular, extensive studies have been actively conducted in the biomedical and related fields, including multidisciplinary and emerging areas, as their stimulating effects on cell behaviors have been becoming an increasing concern. Herein, we are attempting to summarize some of recent findings in the fields of tissue regeneration concerning the graphene family nanomaterial-functionalized biomimetic scaffolds, and to provide the promising perspectives for the possible applications of graphene family nanomaterial.

Tissues are often damaged by physical trauma, infection or tumors. A slight injury heals naturally through the normal healing process, while severe injury causes serious health implications. Therefore, many efforts have been devoted to treat and repair various tissue defects. Recently, tissue engineering approaches have attracted a rapidly growing interest in biomedical fields to promote and enhance healing and regeneration of large-scale tissue defects. On the other hand, with the recent advances in nanoscience and nanotechnology, various nanomaterials have been suggested as novel biomaterials. Graphene, a two-dimensional atomic layer of graphite, and its derivatives have recently been found to possess promoting effects on various types of cells. In addition, their unique properties, such as outstanding mechanical and biological properties, allow them to be a promising option for hard tissue regeneration. Herein, we summarized recent research advances in graphene-based nanocomposites for hard tissue regeneration, and highlighted their promising potentials in biomedical and tissue engineering.

Titanium (Ti) and its alloys are mainly used for dental and orthopedic applications due to their excellent biocompatibility and mechanical properties. However, their intrinsic bioinertness often quotes as a common complaint for biomedical applications. Herein, we produced nanopattern Ti surfaces with 10 nm nanopores in 120 nm dimples by electrochemical nanopattern formation (ENF), and evaluated the osteogenic differentiation of human mesenchymal stem cells (hMSCs) on the nanopattern Ti surfaces. The ENF surfaces were obtained by removing the TiO2 nanotube (NT) layers prepared by an anodization process. To determine the in vitro effects of the ENF surface, cell proliferation assay, alkaline phosphatase activity assay, alizarin red staining, western blotting, and immunocytochemistry were performed. Atomic force microscopy and scanning electron microscopy analysis show that the ENF surface has an ultrafine surface roughness with highly aligned nanoporous morphology. hMSCs on ENF surfaces exhibit increased proliferation and enhanced osteogenic differentiation as compared to the ordered TiO2 nanotubular and compact TiO2 surfaces. Surface modification with the ENF process is a promising technique for fabricating osteointegrative implant materials with a highly bioactive, rigid and purified nano surfaces.

Background Until now, there is no effective anti-fibrotic therapy available for liver cirrhosis. Stem cell therapies have been studied for the treatment of hepatic fibrosis. However, the use of embryonic stem cells or induced pluripotent stem cells (iPSC) has limitations such as ethical concern or malignancy potential. Induced hepatocyte-like cells (iHEPs) generated by direct reprogramming technology may overcome these limitations. Methods In this study, we generated iHEPs by direct reprogramming from mouse embryonic fibroblast (MEF) either using specific transcription factors such as c-Myc and Klf-4 (type A), or adding small molecules to HNF1α (type B). Results We investigated the effect of iHEPs on acute liver injury and chronic hepatic fibrosis animal models induced by CCl4 intra-peritoneal injection in BALB/C nude mice. In acute liver injury model, serum AST/ALT levels peaked at 24 h after CCl4 injection. Intra-splenic transplantation of iHEPs significantly attenuated CCl4-induced acute liver injury. GFP-labeled iHEPs (type A) migrated to the liver after intra-splenic transplantation that was confirmed by Western blotting and immunofluorescence staining. We found that GFP and albumin were co-localized in migrated iHEPs in the liver suggesting migrated iHEPs were functional. In chronic hepatic fibrosis mice experiment, transplantation of either type A or type B iHEPs significantly attenuated liver fibrosis induced by CCl4 injection for 10 weeks. Conclusions Our study suggests that iHEPs may be used as a novel therapeutic strategy for the treatment of hepatic fibrosis. Electronic supplementary material The online version of this article (10.1186/s13287-018-1127-3) contains supplementary material, which is available to authorized users.

Oligodendrocyte progenitor cells (OPCs) are attracting attention as the ideal cell therapy for spinal cord injury (SCI). Recently, advanced reprogramming and differentiation techniques have made it possible to generate therapeutic cells for treating SCI. In the present study, we used directly-induced neural stem cells (DNSCs) from fibroblasts to establish OPCs (DN-OPCs) capable of proliferation and confirmed their OPC-specific characteristics. Also, we evaluated the effect of transplanted DN-OPCs on SCI in rats. The DN-OPCs exhibited an OPC-specific phenotype and electrophysiological function and could be differentiated into oligodendrocytes. In the SCI model, transplanted DN-OPCs improved behavior recovery, and showed engraftment into the host spinal cord with expression of myelin basic protein. These results suggest that DN-OPCs could be a new source of potentially useful cells for treating SCI.

Background Black phosphorus (BP) has emerged as a novel class of nanomaterials owing to its unique optical and electronic properties. BP, a two-dimensional (2D) nanomaterial, is a structure where phosphorenes are stacked together in layers by van der Waals interactions. However, although BP nanodots have many advantages, their biosafety and biological effect have not yet been elucidated as compared to the other nanomaterials. Therefore, it is particularly important to assess the cytotoxicity of BP nanodots for exploring their potentials as novel biomaterials. Methods BP nanodots were prepared by exfoliation with a modified ultrasonication-assisted solution method. The physicochemical properties of BP nanodots were characterized by transmission electron microscopy, dynamic light scattering, Raman spectroscopy, and X-ray diffractometry. In addition, the cytotoxicity of BP nanodots against C2C12 myoblasts was evaluated. Moreover, their cell imaging potential was investigated. Results Herein, we concentrated on evaluating the cytotoxicity of BP nanodots and investigating their cell imaging potential. It was revealed that the BP nanodots were cytocompatible at a low concentration, although the cell viability was decreased with increasing BP nanodot concentration. Furthermore, our results demonstrated that the cells took up the BP nanodots, and the BP nanodots exhibited green fluorescence. Conclusions In conclusion, our findings suggest that the BP nanodots have suitable biocompatibility, and are promising candidates as fluorescence probes for biomedical imaging applications.

Black phosphorus (BP) is a monolayer/multilayer two-dimensional (2D) nanomaterial, which has recently emerged as one of the most attractive 2D nanomaterials due to its fascinating physicochemical and optoelectronical properties. Layered BP may have promising applications in biomedical fields, such as drug delivery, photodynamic/photothermal therapy and bioimaging, although its intrinsic toxicity has not been fully elucidated yet. In the present study, the cytotoxicological effects of layered BP on both cell metabolic activity and membrane integrity were investigated. Layered BPs were prepared using a modified ultrasonication-assisted solution method, and their physicochemical properties were characterized. The dose- and time-dependent cytotoxicity of layered BP was assessed against L-929 fibroblasts. Our findings indicate that the cytotoxicity of BPs is proportionally dependent on their concentration and exposure time, which is affected by the oxidative stress-mediated enzyme activity reduction and membrane disruption. On the other hand, layered BPs did not exhibit significant cytotoxicity at concentrations lower than 4 μg/mL. Therefore, it is suggested that layered BPs can be effectively utilized as therapeutic delivery carriers and imaging agents.

Summary Disorders of the biliary epithelium, known as cholangiopathies, cause severe and irreversible liver diseases. The limited accessibility of bile duct precludes modeling of several cholangiocyte-mediated diseases. Therefore, novel approaches for obtaining functional cholangiocytes with high purity are needed. Previous work has shown that the combination of Hnf1β and Foxa3 could directly convert mouse fibroblasts into bipotential hepatic stem cell-like cells, termed iHepSCs. However, the efficiency of converting fibroblasts into iHepSCs is low, and these iHepSCs exhibit extremely low differentiation potential into cholangiocytes, thus hindering the translation of iHepSCs to the clinic. Here, we describe that the expression of Hnf1α and Foxa3 dramatically facilitates the robust generation of iHepSCs. Notably, prolonged in vitro culture of Hnf1α- and Foxa3-derived iHepSCs induces a Notch signaling-mediated secondary conversion into cholangiocyte progenitor-like cells that display dramatically enhanced differentiation capacity into mature cholangiocytes. Our study provides a robust two-step approach for obtaining cholangiocyte progenitor-like cells using defined factors., Graphical Abstract, Highlights • Hnf1α and Foxa3 (1a3) induce robust generation of iHepSCs from fibroblasts • 1a3-derived iHepSCs are transcriptionally closer to LEPCs than 1b3-iHepSCs • Prolonged culture induces Notch-mediated secondary conversion into iCPCs • This study provides the robust two-step approach for obtaining iCPCs, In this article, Han and colleagues revisited the roles of HepSC-specific factors and found that Hnf1α and Foxa3 facilitate the robust conversion into iHepSCs displaying a relatively closer transcriptional pattern with LEPCs. The prolonged in vitro culture of iHepSCs induces Notch-mediated secondary conversion into iCPCs, which could efficiently be differentiated into mature cholangiocytes.

Neural tissue regeneration is a significant challenge, because severe nerve injury is quite difficult to regenerate spontaneously. Although, many studies have been devoted to promote nerve regeneration, there are still many technical challenges to achieve satisfactory results. In this study, we designed biomimetic matrices composed of aligned laminin core-polydioxanone/collagen shell (Lam-PDO/Col) fibers, which can provide both topographical and biochemical cues for promoting neuritogenesis. The aligned Lam-PDO/Col core-shell fiber matrices were fabricated by magnetic field-assisted electrospinning with the coaxial system, and their potential as biofunctional scaffolds for promoting neuritogenesis was explored. It was demonstrated that the aligned Lam-PDO/Col core-shell fibers were successfully fabricated, and the laminin in the core of fibers was steadily and continuously released from fibers. In addition, the cellular behaviors of hippocampal neuronal cells on the matrices were significantly enhanced. Moreover, the aligned Lam-PDO/Col fiber matrices effectively improved and guided neurite outgrowth as well as the neurogenic differentiation by providing both topographical and biochemical cues through aligned fiber structure and sustained release of laminin. Collectively, it is suggested that the aligned Lam-PDO/Col core-shell fiber matrices are one of the most promising approaches for promoting neuritogenesis and neural tissue regeneration.

In recent years, multimodal contrast agents have attracted considerable attention in biomedical imaging. This paper reports the development of a multimodal nanoprobe based on silica-coated gadolinium oxide nanoparticles (NPs) for T1-enhanced magnetic resonance (MR) and multicolor optical imaging. MR relaxivity measurements showed that these core–shell NPs could generate strong positive contrast enhancement in T1-weighted MR imaging (MRI). Owing to the nominally co-doped Eu3+ and Tb3+ ions in the Gd2O3 host, the synthesized nanoprobes could simultaneously emit blue, green and red fluorescence signals. Furthermore, the cytotoxicity results showed that a thin silica coating on the surface of gadolinium oxide NPs could increase the biocompatibility of the fabricated nanoprobes considerably. The excellent multicolor fluorescence and MRI functionalities of these nanoprobes could have potential biomedical applications.

Osteoprogenitor cells, known as preosteoblasts, that arise from mesenchymal stem cells in the bone marrow are types of cells that work in the growth or repair of bones. These cells possess the prominent potential to differentiate toward the osteogenic lineage, and therefore offer promising opportunities for bone tissue engineering and regenerative therapy. However, to fully exploit the application of osteoprogenitor cells in bone regeneration, it is critical to develop biochemical, physical or pharmaceutical factors that can precisely control their osteogenic differentiation. In this study, we hypothesized that reduced graphene oxide (rGO) and hydroxyapatite (HAp) composites could synergistically enhance the osteogenic differentiation of preosteoblasts. Without interference with the proliferation of MC3T3-E1 preosteoblasts, rGO/HAp composites synergistically enhanced the osteogenic differentiation of the preosteoblasts, which had been confirmed by determining alkaline phosphatase activity and mineralization of calcium and phosphate as early and late stage markers of osteogenic differentiation. This osteogenic activity mediated by rGO/HAp composites was further accelerated under osteogenic culture conditions. It is suggested that rGO/HAp hybrid composites can serve as biocompatible, transferable, and implantable scaffolds for bone regeneration because these graphene-based composite materials have the potential to promote spontaneous osteogenesis in the absence of any osteogenic factors.

The antigen binding to the B cell receptor (BCR) induces a rise in cytoplasmic Ca2+ and initiates cell responses such as apoptosis, proliferation, and differentiation in B lymphocytes. We previously showed that the inhibition of mitochondrial Na+-Ca2+ exchange (NCXm) by 7-chloro-5- (2-chlorophenyl)-1,5-dihydro-4,1-benzothiazepin-2(3H)-one [CGP-37157] dose-dependently reduced BCR-mediated rise in cytoplasmic Ca2+ in DT40 B lymphocytes. However, the effect of CGP-37157 on BCR-mediated apoptosis is not yet fully understood. Here, we studied the effect of NCXm inhibition on BCR-mediated apoptosis in DT40 B lymphocytes. Apoptotic cells (Annexin V+ and PI − ) were increased by the BCR-stimulation while the treatment of cells with 20-μM CGP-37157 attenuated the apoptosis induction. On the other hand, 24-hr treatments with 0.2 − 20 μM CGP- 37157 without the BCR stimulation did not affect the apoptotic-cell population. In the NCLX (a gene encoding NCXm) knockout cells, although the apoptotic cells were increased in the control, the appearance of late apoptotic cells (Annexin V+ and PI+) was decreased by BCR stimulation when compared to the wild-type cells. Our findings suggest that the inhibition of NCXm attenuates BCR-mediated apoptosis in DT40 B lymphocytes.

Currently, applications of graphene and its derivatives have been reported in many fields. In particular, graphene oxide (GO) has been studied for biomedical applications, such as cell imaging, biosensors and drug delivery systems, because of its good biocompatibility and excellent physicochemical properties. Recently, much research has been conducted to control cell behavior, including attachment, proliferation and differentiation by using GO. On the other hand, the effects of GO on myogenic differentiation have not been explored. In the present study, the influence of GO on myogenic differentiation was investigated. This study assessed the cytotoxicity of GO and evaluated the myogenic differentiation of C2C12 murine myoblasts in growth media containing 10 μg/mL of GO. The physicochemical properties of GO were characterized by using atomic force microscopy (AFM) and Raman spectroscopy. The cytotoxicity was evaluated by using a WST-8 assay. An analysis of myogenic differentiation was performed by using immunofluorescence staining for the myosin heavy chain (MHC; myogenic differentiation marker) and was determined by calculating the amount of multinucleate myotube formation, the fusion index and the maturation index. GO did not exhibit cytotoxicity at low concentrations and effectively stimulated the myogenic differentiation of C2C12 murine myoblasts. Therefore, GO has potential skeletal tissue engineering applications.

PURPOSE: This study researched the effects of the changes of elbow joint angle and of arm position in PNF pattern on muscle activation of the contralateral shoulder muscles while performing PNF pattern exercise. METHODS: The research subjects were 16 male physical therapists who had no neuromuscular or neurological disorders. To measure the muscle activation of the contralateral shoulder muscles, EMG electrodes were attached to the muscle valley of the middle and posterior areas of the deltoid and triceps muscles of the arm. Muscle activation while performing the ulnar thrust PNF pattern exercise was measured with the elbow joint positioned at angles of 30°, 45°, and 60°. Resistance points were at the initial, middle, and end ranges of PNF pattern exercise. RESULTS: Muscle activation of the middle and posterior portions of the deltoid muscle increased significantly according to the changes of elbow joint angle. In each resistance point the middle range was significantly higher

Epigallocatechin-3-O-gallate (EGCG), the main polyphenolic component of green tea, has a wide range of pharmacological activities, including antioxidant, anti-inflammatory, and anti-fibrotic effects. In this study, EGCG-loaded poly(lactic-co-glycolic acid) (PLGA) sheets were prepared by electrospinning nanofibers and evaluating their potential as tissue-adhesion barriers. EGCG-loaded PLGA (E-PLGA) fibrous sheets were electrospun from a PLGA solution containing 8% (w/v) EGCG. The average diameter of E-PLGA fibers was 397 ± 159 nm, which was comparable to that of pure PLGA fibers (459 ± 154 nm). EGCG was uniformly dispersed in E-PLGA sheets without direct chemical interactions. E-PLGA fibrous sheets showed sustained release of EGCG by controlled diffusion and PLGA degradation. The attachment and proliferation of L-929 fibroblastic cells were significantly (p < 0.05) suppressed in E-PLGA sheets. Furthermore, E-PLGA fibrous sheets did not induce any inflammatory response to J774A.1 macrophages. The anti-adhesion efficacy of E-PLGA fibrous sheets was evaluated in the intraperitoneal adhesion model in rats. Two weeks after surgical treatment, macroscopic adhesion (extent and severity) scores and histopathological tissue responses of E-PLGA fibrous sheets were significantly lower than those of non-treated controls and pure PLGA sheets. The results suggest that the scores are comparable, and in some cases superior, to those of other commercialized tissue-adhesion barriers. In conclusion, our study findings suggest that E-PLGA fibrous sheets may be exploited as potential tissue-adhesion barriers for the prevention of post-surgical adhesion formation.

Dendritic cells (DCs) are the most potent antigen-presenting cells that play a crucial role in the initiation of an immune response. As DC-based therapeutic applications is increasing, large-scale DC production is required for transplantation. Human umbilical cord blood (UCB) has been shown to contain a rare and precious population of hematopoietic stem cells (HSCs), which can give rise to DCs. The CD34 antigen has been widely used as a cell surface marker to identify HSCs. In this study, we used CD34 antibody to isolate CD34(+) and CD34(-) cells and compared the ability to differentiate into DCs. We used a two-step method combined with the magnetic bead sorting system to isolate CD34(+) and CD34(-) cells from human UCB. Analysis of cellular properties and functionality using a migration assay and T cell proliferation assay revealed no significant differences between CD34(+) cells and CD34(-) cells in their ability to generate DCs.

This study investigated the effects of a specific regimen of resistance training on coordinated actions of human hand digits during grasping. Participants were instructed to hold a rectangular object with all five digits and to maintain the orientation of the object against transient perturbation. Indices of co-varied actions (i.e., synergies) among multi-digit grasping and rotational actions were quantified. The index of anticipatory changes of co-varied actions among digit forces (i.e., anticipatory synergy adjustment) was also quantified, which represents the controller's ability to predict an upcoming perturbation. The synergies of both grasping force and moment stabilization increased with the training. No change in the index of anticipatory synergy adjustment with training was observed. The current results suggest that the resistance training on the wrist could be an effective way to enhance both voluntary muscle force/torque production capability and ability to stabilize task performances during multi-digit prehensile tasks.

Neural stem cells (NSCs) are capable of self-renewal and can differentiate into neurons and two types of glial cells. NSCs have great potential for basic studies of neurogenesis and neurodegenerative diseases, and for therapeutic transplantation applications. NSCs can be derived from the fetal or adult brain. In vitro expansion of NSCs may help to elucidate their properties involved in neurogenesis and is crucial to obtain on-demand the large numbers of these cells needed for clinical transplantation trials. Laminin is an extracellular matrix molecule commonly used to culture NSCs as an attached monolayer. However, laminin is costly if NSCs need to be cultured in large quantities. Matrigel is a soluble basement membrane biomaterial, which has been widely used for feeder-free cultures of human embryonic stem cells. In the present study, we evaluated the ability of Matrigel to support the attachment and long-term proliferation of NSCs. We investigated the growth and adherence of NSCs derived from th...

The baculovirus–insect cell expression system is widely used to produce recombinant proteins for various biomedical applications. Our previous study demonstrated that EpCAM, a colorectal cancer vaccine candidate protein, can be expressed in the baculovirus–insect cell expression system. However, its functionality (the ability to elicit an immune response), which is important for its possible use as a colorectal cancer vaccine for immunotherapy, still needed to be confirmed. In this study, we examined the ability of recombinant EpCAM to induce maturation of immature dendritic cells (DCs) derived from CD34+ cells isolated from human umbilical cord blood. We demonstrated that EpCAM induces the expression of four DC maturation markers: CD80, CD83, CD86 and MHC II. These results suggest that EpCAM produced in the baculovirus–insect cell expression system is functional in terms of its ability to trigger maturation of human DCs.

For the treatment of periodontitis, local delivery of antibiotics and their sustained release are preferable to enhance microbial susceptibility and to reduce possible side effects occurrence in systemic drug delivery. To address these issues, antibiotic loaded polymeric matrices implantable into periodontal pocket have been commercially used in dentistry and oral medicine. Recently, keratin has been drawing attention as a natural polymer for its ability to mediate cell behavior with minor or no immunogenicity enabling further process towards autologous implantation. In this study, human hair keratin was extracted with a cocktail of reducing agents, and antibiotic eluting keratin-based biofilms were fabricated. Physicochemical analysis and release test showed proper physical stability and sustained release of the loaded antibiotics. In addition, the released antibiotic suppressed the growth of various types of oral bacteria including porphyromonas gingivalis. Cellular interaction studies showed that human oral epithelial cell, human gingival fibroblast and periodontal ligament cells proliferated and guided well on biofilms. This study propose that antibiotic eluting keratin-based biofilms are provisional device for the treatment of chronic periodontitis offering advantages such as local controlled drug delivery and biocompatibility, and human hair keratin is able to be a good biomaterial for the potent applications to tissue engineering and regenerative medicine. Open image in new window

Tissues are often damaged by physical trauma, infection or tumors. A slight injury heals naturally through the normal healing process, while severe injury causes serious health implications. Therefore, many efforts have been devoted to treat and repair various tissue defects. Recently, tissue engineering approaches have attracted a rapidly growing interest in biomedical fields to promote and enhance healing and regeneration of large-scale tissue defects. On the other hand, with the recent advances in nanoscience and nanotechnology, various nanomaterials have been suggested as novel biomaterials. Graphene, a two-dimensional atomic layer of graphite, and its derivatives have recently been found to possess promoting effects on various types of cells. In addition, their unique properties, such as outstanding mechanical and biological properties, allow them to be a promising option for hard tissue regeneration. Herein, we summarized recent research advances in graphene-based nanocomposites for hard tissue regeneration, and highlighted their promising potentials in biomedical and tissue engineering.

Graphene is a two-dimensional atomic layer of graphite, where carbon atoms are assembled in a honeycombed lattice structure. Recently, graphene family nanomaterials, including pristine graphene, graphene oxide and reduced graphene oxide, have increasingly attracted a great deal of interest from researchers in a variety of science, engineering and industrial fields because of their unique structural and functional features. In particular, extensive studies have been actively conducted in the biomedical and related fields, including multidisciplinary and emerging areas, as their stimulating effects on cell behaviors have been becoming an increasing concern. Herein, we are attempting to summarize some of recent findings in the fields of tissue regeneration concerning the graphene family nanomaterial-functionalized biomimetic scaffolds, and to provide the promising perspectives for the possible applications of graphene family nanomaterial.

Human mesenchymal stem cells (hMSCs) have great potential as cell sources for bone tissue engineering and regeneration, but the control and induction of their specific differentiation into bone cells remain challenging. Graphene-based nanomaterials are considered attractive candidates for biomedical applications such as scaffolds in tissue engineering, substrates for SC differentiation and components of implantable devices, due to their biocompatible and bioactive properties. Despite the potential biomedical applications of graphene and its derivatives, only limited information is available regarding their osteogenic activity. This study concentrates upon the effects of reduced graphene oxide (rGO)-coated hydroxyapatite (HAp) composites on osteogenic differentiation of hMSCs. The average particle sizes of HAp and rGO were 1270 ± 476 nm and 438 ± 180 nm, respectively. When coated on HAp particulates, rGO synergistically enhanced spontaneous osteogenic differentiation of hMSCs, without hampering their proliferation. This result was confirmed by determining alkaline phosphatase activity and mineralization of calcium and phosphate as early and late stage markers of osteogenic differentiation. It is suggested that rGO-coated HAp composites can be effectively utilized as dental and orthopedic bone fillers since these graphene-based particulate materials have potent effects on stimulating the spontaneous differentiation of MSCs and show superior bioactivity and osteoinductive potential.

SummaryA recent study has suggested that fibroblasts can be converted into mouse-induced neural stem cells (miNSCs) through the expression of defined factors. However, successful generation of human iNSCs (hiNSCs) has proven challenging to achieve. Here, using microRNA (miRNA) expression profile analyses, we showed that let-7 microRNA has critical roles for the formation of PAX6/NESTIN-positive colonies from human adult fibroblasts and the proliferation and self-renewal of hiNSCs. HMGA2, a let-7-targeting gene, enables induction of hiNSCs that displayed morphological/molecular features and in vitro/in vivo differentiation potential similar to H9-derived NSCs. Interestingly, HMGA2 facilitated the efficient conversion of senescent somatic cells or blood CD34+ cells into hiNSCs through an interaction with SOX2, whereas other combinations or SOX2 alone showed a limited conversion ability. Taken together, these findings suggest that HMGA2/let-7 facilitates direct reprogramming toward hiNSCs in minimal conditions and maintains hiNSC self-renewal, providing a strategy for the clinical treatment of neurological diseases.

Extracellular matrices (ECMs) are network structures that play an essential role in regulating cellular growth and differentiation. In this study, novel nanofibrous matrices were fabricated by electrospinning M13 bacteriophage and poly(lactic-co-glycolic acid) (PLGA) and were shown to be structurally and functionally similar to natural ECMs. A genetically-engineered M13 bacteriophage was constructed to display Arg-Gly-Asp (RGD) peptides on its surface. The physicochemical properties of RGD peptide-displaying M13 bacteriophage (RGD-M13 phage)/PLGA nanofibers were characterized by using scanning electron microscopy and Fourier-transform infrared spectroscopy. We used immunofluorescence staining to confirm that M13 bacteriophages were homogenously distributed in RGD-M13 phage/PLGA matrices. Furthermore, RGD-M13 phage/PLGA nanofibrous matrices, having excellent biocompatibility, can enhance the behaviors of vascular smooth muscle cells. This result suggests that RGD-M13 phage/PLGA nanofibrous matrices have potentials to serve as tissue engineering scaffolds.