LRRC15 expression indicates high level of stemness regulated by TWIST1 in mesenchymal stem cells

Mesenchymal stem cells (MSCs) are used as a major source for cell therapy, and its application is expanding in various diseases. On the other hand, reliable method to evaluate quality and therapeutic properties of MSC is limited. In this study, we focused on TWIST1 that is a transcription factor regulating stemness of MSCs and found that the transmembrane protein LRRC15 tightly correlated with the expression of TWIST1 and useful to expect TWIST1-regulated stemness of MSCs. The LRRC15-positive MSC populations in human and mouse bone marrow tissues highly expressed stemness-associated transcription factors and therapeutic cytokines, and showed better therapeutic effect in bleomycin-induced pulmonary fibrosis model mice. This study provides evidence for the important role of TWIST1 in the MSC stemness, and for the utility of the LRRC15 protein as a marker to estimate stem cell quality in MSCs before cell transplantation.

Fibrinogen supports self-renewal of mesenchymal stem cells under serum-reduced condition through autophagy activation

Mesenchymal stem cells (MSCs) are somatic stem cells used in cell transplantation therapy for tissue injuries and inflammatory diseases because of their ability to support tissue regeneration and to suppress inflammation. While their applications are expanding, needs for automation of culture procedures with reduction of animal-derived materials to meet stable quality and suppliability are also increasing. On the other hand, the development of molecules that safely support cell adherence and expansion on a variety of interfaces under the serum-reduced culture condition remains a challenge. We report here that fibrinogen enables MSC culture on various materials with low cell adhesion property even under serum-reduced culture conditions. Fibrinogen promoted MSC adhesion and proliferation by stabilizing basic fibroblast growth factor (bFGF), which was secreted in the culture medium by autocrine, and also activated autophagy to suppress cellar senescence. Fibrinogen coating allowed MSCs expansion even on the polyether sulfone membrane that represents very low cell adhesion, and the MSCs showed therapeutic effects in a pulmonary fibrosis model. This study demonstrates that fibrinogen is currently the safest and most widely available extracellular matrix and can be used as a versatile scaffold for cell culture in regenerative medicine.

Depletion of NIMA-related kinase Nek2 induces aberrant self-renewal and apoptosis in stem/progenitor cells of aged muscular tissues

Frailty of the locomotory organs has become a widespread problem in the geriatric population. The major factor leading to frailty is an age-associated decrease in muscular mass and a reduced number of muscular cells and myofibers. In aged muscular tissues, muscular satellite cells (MuSCs) are reduced due to abnormalities in their self-renewal and the induction of apoptosis. However, the molecular mechanisms connecting aging-associated physiological changes and the reduction of MuSCs are largely unknown. NIMA-related kinase 2 (Nek2), a member of the Nek family of serine/threonine kinases, was found to be downregulated in aged MuSCs/progenitors. Further, Nek2 downregulation was found to inhibit self-renewal and apoptotic cell death by activating the p53-dependent checkpoint. Attenuated NEK2 expression was also observed in the muscular tissues of elderly donors, and its function was confirmed to be conserved in humans. Overall, this study proposes a novel mechanism for inducing muscular atrophy to understand aging-associated muscular diseases.

Folate receptor α increases chemotherapy resistance through stabilizing MDM2 in cooperation with PHB2 that is overcome by MORAb-202 in gastric cancer

BACKGROUND

The main function of folate receptor α (FOLRα) has been considered to mediate intracellular folate uptake and induce tumor cell proliferation. Given the broad spectrum of expression among malignant tumors, including gastric cancer (GC) but not in normal tissue, FOLRα represents an attractive target for tumor-selective drug delivery. However, the efficacy of anti-FOLRα monoclonal antibodies (mAbs) has not been proved so far, with the reason for this failure remaining unclear, raising the need for a better understanding of FOLRα function.

METHODS

The distribution of FOLRα in GC cells was evaluated by immunohistochemistry. The impacts of FOLRα expression on the survival of GC patients and GC cell lines were examined with the Gene Expression Omnibus database and by siRNA of FOLRα. RNA-sequencing and Microarray analysis was conducted to identify the function of FOLRα. Proteins that interact with FOLRα were identified with shotgun LC-MS/MS. The antitumor efficacy of the anti-FOLRα mAb farletuzumab as well as the antibody-drug conjugate (ADC) consists of the farletuzumab and the tublin-depolymerizing agent eribulin (MORAb-202) was evaluated both in vitro and in vivo.

RESULTS

FOLRα was detected both at the cell membrane and in the cytoplasm. Shorter overall survival was associated with FOLRα expression in GC patients, whereas reduction of FOLRα attenuated cell proliferation without inducing cell death in GC cell lines. Transcriptomic and proteomic examinations revealed that the FOLRα-expressing cancer cells possess a mechanism of chemotherapy resistance supported by MDM2, and FOLRα indirectly regulates it through a chaperone protein prohibitin2 (PHB2). Although reduction of FOLRα brought about vulnerability for oxaliplatin by diminishing MDM2 expression, farletuzumab did not suppress the MDM2-mediated chemoresistance and cell proliferation in GC cells. On the other hand, MORAb-202 showed significant antitumor efficacy.

CONCLUSIONS

The ADC could be a more reasonable choice than mAb as a targeting agent for the FOLRα-expressing tumor.

Efficacy of sliced nerves of different thickness in a biodegradable nerve conduit to promote Schwann cell migration and axonal growth: An experimental study in the rat model

BACKGROUND

Using the rat sciatic nerve model, sliced nerves of different thickness was combined to a biodegradable nerve conduit and the amount of nerve fragment necessary to promote nerve regeneration was investigated.

MATERIALS AND METHODS

Harvested sciatic nerve (n = 6) was processed in sliced nerve of the different width; 2, 1, 0.5 mm, respectively. Western blot analysis was carried out to determine protein expression of Erk1/2. Subsequently, a total of 246 rats were used to create a 10 mm gap in the sciatic nerve. A polyglycolic acid-based nerve conduit was used to bridge the gap, with one sliced (width; 2, 1, 0.5 mm) or two (width; 1 mm × 2) incorporated within the conduit (n = 6 at each point in each group). At 2, 4, 8, and 20 weeks after surgery, samples were resected and subjected to immune-histological, transmission electron microscopic, and motor functional evaluation for nerve regeneration.

RESULTS

Western blot analysis demonstrated Erk1/2 expressions were significantly increased in the groups of 2-mm and 1-mm width and attenuated in the 0.5-mm width group (p < .05). The immune-histological study showed the migration of Schwann cells and axon elongation were significantly extended in the groups of 2-mm, 1-mm, and 1 mm × 2 width at 4 weeks (p < .01), in which nerve conduction velocity was marked at 20 weeks (p < .01) after implantation.

CONCLUSION

When nerve tissue was inserted in the biodegradable nerve conduit as a sliced nerve, the method of inserting two sheets with a slice width of 1 mm most strongly accelerated motor function.

miR-142 induces accumulation of reactive oxygen species (ROS) by inhibiting pexophagy in aged bone marrow mesenchymal stem cells

Elevation of the levels of reactive oxygen species (ROS) is a major tissue-degenerative phenomenon involved in aging and aging-related diseases. The detailed mechanisms underlying aging-related ROS generation remain unclear. Presently, the expression of microRNA (miR)-142-5p was significantly upregulated in bone marrow mesenchymal stem cells (BMMSCs) of aged mice. Overexpression of miR-142 and subsequent observation revealed that miR-142 involved ROS accumulation through the disruption of selective autophagy for peroxisomes (pexophagy). Mechanistically, attenuation of acetyltransferase Ep300 triggered the upregulation of miR-142 in aged BMMSCs, and miR-142 targeted endothelial PAS domain protein 1 (Epas1) was identified as a regulatory protein of pexophagy. These findings support a novel molecular mechanism relating aging-associated ROS generation and organelle degradation in BMMSCs, and suggest a potential therapeutic target for aging-associated disorders that are accompanied by stem cell degeneration.

Transforming Growth Factor β-Activated Kinase 1 Regulates Mesenchymal Stem Cell Proliferation Through Stabilization of Yap1/Taz Proteins

Bone marrow-derived mesenchymal stem cells (BMMSCs) are multipotent stem cells capable of differentiation into a variety of cell types, proliferation, and production of clinically useful secretory factors. These advantages make BMMSCs highly useful for cell transplantation therapy. However, the molecular network underlying BMMSC proliferation remains poorly understood. Here, we showed that TGFβ-activated kinase 1 (Tak1) is a critical molecule that regulates the activation of cell cycling and that Tak1 inhibition leads to quiescence in BMMSCs both in vivo and in vitro. Mechanistically, Tak1 was phosphorylated by growth factor stimulations, allowing it to bind and stabilize Yap1/Taz, which could then be localized to the nucleus. We also demonstrated that the quiescence induction by inhibiting Tak1 increased oxidized stress tolerance and improved BMMSC engraftment in intramuscular and intrabone marrow cell transplantation models. This study reveals a novel pathway controlling BMMSC proliferation and suggests a useful method to improve the therapeutic effect of BMMSC transplantation. Stem Cells 2019;37:1595-1605.

Involvement of ADAM12 in Chondrocyte Differentiation by Regulation of TGF-β1-Induced IGF-1 and RUNX-2 Expressions

A disintegrin and metalloproteinase 12 (ADAM12) is known to be involved in chondrocyte proliferation and maturation; however, the mechanisms are not fully understood. In this study, expression and localization of ADAM12 during chondrocyte differentiation were examined in the mouse growth plate by immunohistochemistry. Adam12 expression during ATDC5 chondrogenic differentiation was examined by real-time PCR and compared with the expression pattern of type X collagen. The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system was used to generate Adam12-knockout (KO) ATDC5 cells. Adam12-KO and Adam12 overexpressing cells were used for analyses of ADAM12 expression with or without TGF-β1 stimulation. ADAM12 was identified predominantly in chondrocytes of the proliferative zone in mouse growth plates by immunohistochemistry. Adam12 was upregulated prior to Col10a1 during chondrogenic differentiation in wild-type ATDC5 cells. In Adam12-KO ATDC5 cells, following initiation of chondrogenic differentiation, we observed a reduction in Igf-1 expression along with an upregulation of hypertrophy-associated Runx2, Col10a1, and type X collagen protein expressions. In ATDC5 wild-type cells, stimulation with TGF-β1 upregulated the expressions of Adam12 and Igf-1 and downregulated the expression of Runx2. In contrast, in Adam12-KO ATDC5 cells, these TGF-β1-induced changes were suppressed. Adam12 overexpression resulted in an upregulation of Igf-1 and downregulation of Runx2 expression in ATDC5 cells. The findings suggest that ADAM12 has important role in the regulation of chondrocyte differentiation, potentially by regulation of TGF-β1-dependent signaling and that targeting of ADAM12 may have a role in management of abnormal chondrocyte differentiation.

Thoracoscopic Esophagectomy for a Patient With Perforated Esophageal Epiphrenic Diverticulum After Kidney Transplantation: A Case Report

A 58-year-old man who underwent cadaveric kidney transplantation twice presented to hospital with a perforated epiphrenic diverticulum. Computed tomography revealed epiphrenic diverticulitis and right pleural effusion. Upper gastrointestinal fibroscopy showed an epiphrenic diverticulum full of food residue. He was transferred to our hospital, where we performed percutaneous endoscopic gastrostomy under general anesthesia in the supine position before thoracoscopy. Thoracoscopic esophagectomy was performed in the semi-prone position under 6-10 mmHg artificial pneumothorax via the right thoracic cavity. We performed subtotal esophagectomy to remove sources of infection because the esophageal wall surrounding the diverticulum was too thick to close or to perform diverticulectomy. A cervical esophagostomy was constructed after the thoracic procedure. The patient was managed with continuous hemodiafiltration and administered immunosuppressants and steroids to preserve the transplanted kidney. Continuous hemodiafiltration was stopped on postoperative day (POD) 4. The patient was discharged from the intensive care unit on POD 10 and transferred to the original hospital on POD 24 for rehabilitation. The second operative stage was performed on POD 157 at our hospital. We performed gastric tube reconstruction via the ante-sternal route and anastomosed the tube to the cervical esophagus. The postoperative course was uneventful; the patient was transferred to the original hospital on POD 15 after the second operation. Minimally invasive surgery was sufficient to treat perforated epiphrenic diverticulum while preserving the transplanted kidney. We recommend completely removing the source of infection and reducing surgical invasiveness to preserve the transplanted kidney in cases of esophageal perforation following kidney transplantation.

miR-155 induces ROS generation through downregulation of antioxidation-related genes in mesenchymal stem cells

Inflammation‐induced reactive oxygen species (ROS) are implicated in cellular dysfunction and an important trigger for aging‐ or disease‐related tissue degeneration. Inflammation‐induced ROS in stem cells lead to deterioration of their properties, altering tissue renewal or regeneration. Pathological ROS generation can be induced by multiple steps, and dysfunction of antioxidant systems is a major cause. The identification of the central molecule mediating the above‐mentioned processes would pave the way for the development of novel therapeutics for aging, aging‐related diseases, or stem cell therapies. In recent years, microRNAs (miRNAs) have been shown to play important roles in many biological reactions, including inflammation and stem cell functions. In inflammatory conditions, certain miRNAs are highly expressed and mediate some cytotoxic actions. Here, we focused on miR‐155, which is one of the most prominent miRNAs in inflammation and hypothesized that miR‐155 participates to inflammation‐induced ROS generation in stem cells. We observed mesenchymal stem cells (MSCs) from 1.5‐year‐old aged mice and determined that antioxidants, Nfe2l2, Sod1, and Hmox1, were suppressed, while miR‐155‐5p was highly expressed. Subsequent in vitro studies demonstrated that miR‐155‐5p induces ROS generation by suppression of the antioxidant genes by targeting the common transcription factor C/ebpβ. Moreover, this mechanism occurred during the cell transplantation process, in which ROS generation is triggering loss of transplanted stem cells. Finally, attenuation of antioxidants and ROS accumulation were partially prevented in miR‐155 knockout MSCs. In conclusion, our study suggests that miR‐155 is an important mediator connecting aging, inflammation, and ROS generation in stem cells.

Inflammation-induced miRNA-155 inhibits self-renewal of neural stem cells via suppression of CCAAT/enhancer binding protein β (C/EBPβ) expression

Intracerebral inflammation resulting from injury or disease is implicated in disruption of neural regeneration and may lead to irreversible neuronal dysfunction. Analysis of inflammation-related microRNA profiles in various tissues, including the brain, has identified miR-155 among the most prominent miRNAs linked to inflammation. Here, we hypothesize that miR-155 mediates inflammation-induced suppression of neural stem cell (NSC) self-renewal. Using primary mouse NSCs and human NSCs derived from induced pluripotent stem (iPS) cells, we demonstrate that three important genes involved in NSC self-renewal (Msi1, Hes1 and Bmi1) are suppressed by miR-155. We also demonstrate that suppression of self-renewal genes is mediated by the common transcription factor C/EBPβ, which is a direct target of miR-155. Our study describes an axis linking inflammation and miR-155 to expression of genes related to NSC self-renewal, suggesting that regulation of miR-155 may hold potential as a novel therapeutic strategy for treating neuroinflammatory diseases.

ZEB1 induces EPB41L5 in the cancer mesenchymal program that drives ARF6-based invasion, metastasis and drug resistance

Onset of the cancer mesenchymal program is closely associated with cancer malignancy and drug resistance. Among the different epithelial–mesenchymal transition (EMT)-associated transcriptional factors, ZEB1 has a key role in inducing the mesenchymal phenotypes and stem cell-like properties of different breast cancer cells. ARF6 and its effector AMAP1 are frequently overexpressed in breast cancer cells, and promote invasion, metastasis and drug resistance. EPB41L5 is induced during EMT, and mediates the disruption of E-cadherin-based cell–cell adhesion and the promotion of focal adhesion dynamics. Here we show that EPB41L5 is an integral component of the ARF6-based pathway, which is induced by ZEB1. We found that EPB41L5 is expressed at high levels in malignant breast cancer cells and binds to AMAP1. ZEB1 induced EPB41L5 both in cancer cells and normal cells. This relationship was recaptured with The Cancer Genome Atlas RNASeq data set, and correlated with the poor outcome of the patients. In contrast, diversified events, such as tumor growth factor β1 stimulation, expression of SNAI1 and TP53 mutation, can each cause the induction of ZEB1 and EPB41L5, depending on the cellular context. Our results demonstrated that the ZEB1-EPB41L5 axis is at the core of the cancer mesenchymal program that drives ARF6-based invasion, metastasis and drug resistance of significant populations of primary breast cancers, and is tightly correlated with the poor outcomes of patients.

Cdh2 stabilizes FGFR1 and contributes to primed-state pluripotency in mouse epiblast stem cells

The cell adhesion molecule Cadherin 2 (Cdh2) plays important roles in somatic cell adhesion, proliferation and migration. Cdh2 is also highly expressed in mouse epiblast stem cells (mEpiSCs), but its function in these cells is unknown. To understand the function of Cdh2 in mEpiSCs, we compared the expression of pluripotency-related genes in mEpiSCs and mouse embryonic stem cells (mESCs) after either Cdh2 knockdown or Cdh2 over-expression. Introduction of specific siRNA against Cdh2 led to attenuation of pluripotency-related genes. Pluripotent gene expression was not recovered by over-expression of Cdh1 following Cdh2 knockdown. Western blot analysis and co-immunoprecipitation assays revealed that Cdh2 stabilizes FGFR1 in mEpiSCs. Furthermore, stable transfection of mESCs with Cdh2 cDNA followed by FGF2 supplementation accelerated cell differentiation. Thus, Cdh2 contributes to the establishment and maintenance of FGF signaling-dependent self-renewal in mEpiSCs through stabilization of FGFR1.

Reactive oxygen species induce Cox-2 expression via TAK1 activation in synovial fibroblast cells

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Oxidative stress in the arthritis joint is involved in generating mediators for inflammation.

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Oxidative stress-induced expression of Cox-2 was mediated by MAPKs and NF-κB.

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ROS-induced MAPKs and NF-κB were attenuated by inhibition of MAPKKK TAK1.

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Inhibition of TAK1 activity resulted in reduced expression of Cox-2 and PGE2.

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ROS-induced TAK1 activation and Cox-2 expression was inhibited by antioxidants N-acetyl cysteamine and hyaluronic acid.

Oxidative stress within the arthritis joint has been indicated to be involved in generating mediators for tissue degeneration and inflammation. COX-2 is a mediator in inflammatory action, pain and some catabolic reactions in inflamed tissues. Here, we demonstrated a direct relationship between oxidative stress and Cox-2 expression in the bovine synovial fibroblasts. Furthermore, we elucidated a novel mechanism, in which oxidative stress induced phosphorylation of MAPKs and NF-κB through TAK1 activation and resulted in increased Cox-2 and prostaglandin E2 expression. Finally, we demonstrated that ROS-induced Cox-2 expression was inhibited by supplementation of an antioxidant such as N-acetyl cysteamine and hyaluronic acid in vitro and in vivo. From these results, we conclude that oxidative stress is an important factor for generation of Cox-2 in synovial fibroblasts and thus its neutralization may be an effective strategy in palliative therapy for chronic joint diseases.

Hyaluronic acid regulates a key redox control factor Nrf2 via phosphorylation of Akt in bovine articular chondrocytes

One important pharmacological function of hyaluronic acid (HA) in chondrocytes is reduction of cellular superoxide generation and accumulation. Here we demonstrated a relationship between HA supplementation and accumulation of Nuclear factor-erythroid-2-related factor 2 (Nrf2), which is a master transcription factor in cellular redox reactions, in cultured chondrocytes derived from bovine joint cartilage. In HA-treated chondrocytes, expression of Nrf2 and its downstream genes was upregulated. In HA-treated chondrocytes, Akt was phosphorylated, and inhibition of Akt activity or suppression of HA receptors CD44 and/or RHAMM with siRNAs prevented HA-mediated Nrf2 accumulation. Furthermore, Nrf2 siRNA inhibited the HA effect on antioxidant enzymes. These results show that HA might contribute to ROS reduction through Nrf2 regulation by activating Akt. Our study suggests a new mechanism for extracellular matrix (ECM)-mediated redox systems in chondrocytes.

Generation of embryonic stem cell lines from immature rabbit ovarian follicles

In mammalian ovaries, many immature follicles remain after the dominant follicles undergo ovulation. Here we report the successful production of rabbit embryonic stem cells (ESCs) from oocytes produced by in vitro culture of immature follicles and subsequent in vitro maturation treatment. In total, we obtained 53 blastocysts from oocytes that received intracytoplasmic sperm injection followed by in vitro culture. Although only weak expression of POU5f1 was observed in the inner cell masses of in-vitro-cultured follicle-derived embryos, repeated careful cloning enabled establishment of 3 stable ESC lines. These ESC lines displayed the morphological characteristics of primed pluripotent stem cells. The ESC lines also expressed the pluripotent markers Nanog, POU5f1, and Sox2. Further, these ESCs could be differentiated into each of the 3 different germ layers both in vitro and in vivo. These results demonstrate that immature follicles from rabbits can be used to generate ESCs. Moreover, the use of rabbit oocytes as a cell source provides an experimental system that closely matches human reproductive and stem cell physiology.

Induction of Functional Mesenchymal Stem Cells from Rabbit Embryonic Stem Cells by Exposure to Severe Hypoxic Conditions

Embryonic stem cells (ESCs) have the potential to be used as an unlimited cell source for cell transplantation therapy, as well as for studying mechanisms of disease and early mammalian development. However, applications involving ESCs have been limited by the lack of reliable differentiation methods in many cases. Mesenchymal stem cells (MSCs) have also emerged as a promising cell source, but as suggested in recent studies, these cells display limited potential for proliferation and differentiation, thereby limiting their usefulness in the clinic and in the laboratory. Unfortunately, effective methods for induction of MSCs from pluripotent stem cells have not been established, and the development of such methods remains a major challenge facing stem cell biologists. Oxygen concentration is one of the most important factors regulating tissue development. It has profound effects on cell metabolism and physiology and can strongly influence stem cell fate. Here we demonstrate that severe low O2 concentrations (1%) can function as a selective pressure for removing undifferentiated pluripotent cells during the induction of MSCs from rabbit ESCs (rESCs) and that MSCs induced under severe hypoxic conditions function as normal MSCs; that is, they repopulate after cloning, express specific markers (vimentin, CD29, CD90, CD105, and CD140a) and differentiate into adipocytes, osteoblasts, and chondrocytes. Furthermore, we demonstrate that these cells can contribute to cartilage regeneration in an in vivo rabbit model for joint cartilage injury. These results support the notion that exposing ESCs to severe hypoxic conditions during differentiation can be used as a strategy for the preparation of functional MSCs from ESCs.

Abstract P6-05-14: Estrogen-induced genes in ductal carcinoma in situ(DCIS): their comparison with invasive ductal carcinoma

It is well known that estrogens play important roles in both the pathogenesis and development of invasive ductal carcinoma (IDC) of human breast. However, molecular features of estrogen actions have remained largely unclear in pure ductal carcinoma in situ (pDCIS), regarded as a precursor lesion of many IDCs. This is partly due to the fact that gene expression profiles of estrogen-responsive genes have not been examined in pDCIS. Therefore, we first examined the profiles of estrogen-induced genes in estrogen receptor (ER)-positive pDCIS and DCIS (DCIS-c) and IDC (IDC-c) components of IDC cases (n = 4, respectively) by microarray analysis. Estrogen-induced genes identified in this study were tentatively classified into three different groups in the hierarchical clustering analysis, and 33% of the genes were predominantly expressed in pDCIS rather than DCIS-c or IDC-c cases. Among these genes, the status of MYB (c-MYB), RBBP7 (RbAp46) and BIRC5 (survivin) expression in carcinoma cells was significantly higher in ER-positive pDCIS(n = 53) than that in ER-positive DCIS-c (n = 27) or IDC-c (n = 27) by subsequent immunohistochemical analysis of the corresponding genes (P &lt; 0.0001, P = 0.03 and P = 0.0003, respectively). In particular, the status of c-MYB immunoreactivity was inversely (P = 0.006) correlated with Ki-67 in the pDCIS cases. These results suggest that expression profiles of estrogen-induced genes in pDCIS may be different from those in IDC, and c-MYB, RbAp46 and survivin may play particularly important roles among estrogen induced genes in ER-positive pDCIS.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-05-14.

Mechanical stimulation of cyclic tensile strain induces reduction of pluripotent related gene expressions via activation of Rho/ROCK and subsequent decreasing of AKT phosphorylation in human induced pluripotent stem cells

Mechanical stimulation has been shown to regulate the proliferation and differentiation of stem cells. However, the effects of the mechanical stress on the stemness or related molecular mechanisms have not been well determined. Pluripotent stem cells such as embryonic stem (ES) cells and induced pluripotent stem (iPS) cells are used as good materials for cell transplantation therapy and research of mammalian development, since they can self-renew infinitely and differentiate into various cell lineages. Here we demonstrated that the mechanical stimulation to human iPS cells altered alignment of actin fibers and expressions of the pluripotent related genes Nanog, POU5f1 and Sox2. In the mechanically stimulated iPS cells, small GTPase Rho was activated and interestingly, AKT phosphorylation was decreased. Inhibition of Rho-associated kinase ROCK recovered the AKT phosphorylation and the gene expressions. These results clearly suggested that the Rho/ROCK is a potent primary effector of mechanical stress in the pluripotent stem cells and it participates to pluripotency-related signaling cascades as an upper stream regulator.

Reduced oxygen concentration enhances conversion of embryonic stem cells to epiblast stem cells

Recently, an additional type of pluripotent stem cell-line derived from mouse embryos has been established and termed epiblast stem cell (EpiSC), and is expected to be an important tool for studying the mechanisms of maintenance of pluripotency since they depend on basic fibroblast growth factor-MAPK and Activin A-Smad2/3 signaling to maintain pluripotency, unlike mouse embryonic stem cells (ESCs). Further, because of the similarities between mouse EpiSCs and human ESCs, EpiSCs are expected to be effective experimental models for human stem cell therapy. Recently, study for conversion from ESC state to EpiSC state or reversion from EpiSC state to ESC state has attracted interest since these techniques may lead to increasing the potential of pluripotent stem cells and our knowledge about their developmental status. In the present study, we find that a low oxygen concentration in culture environment accelerated, improved, and stabilized the EpiSC state of the converted cells from the ESC state using Oct4ΔPE-GFP transgenic ESCs. Induced EpiSCs (iEpiSCs) in hypoxia possess closer gene expression patterns to native EpiSCs, and bisulfite sequences for the promoter regions of Stella and Oct4 genes have elucidated that the iEpiSC gain EpiSC-specific methylation patterns in hypoxia. Our data provide evidence that oxygen concentration is an important factor for establishment of the EpiSC-specific state.

Induction of mesenchymal progenitor cells with chondrogenic property from mouse-induced pluripotent stem cells

Despite recent cell-engineering advances, treatment and repair of cartilage remains challenging. Although stem cell transplantation therapy using mesenchymal stem cells (MSCs) is considered a prominent strategy, the major problem of limited proliferative capacity of autologous cells has been unsolved. Recently, an induced pluripotent stem (iPS) cell line was suggested as an alternative way to cure various human diseases due to their potential proliferating infinitely while possessing the capacity to form all types of cells. However, the method to induce lineage-restricted differentiation has not been well examined or established. Here, we suggest a simple method to induce mesenchymal progenitors possessing chondrogenic property from mouse iPS cells. The MSC-like cells produced in our study expressed some MSC markers, and could also differentiate to osteoblast and adipocyte. The present study demonstrates the property of iPS cells as an alternative candidate for treatment of articular disorders, and suggests an effective approach for preparing chondrocyte from iPS cells.

Leukemia inhibitory factor (LIF) enhances germ cell differentiation from primate embryonic stem cells

Recently, several research groups have shown that germ cells can be produced in vitro from pluripotent embryonic stem cells (ESCs). In the mouse, live births of offspring using germ cells induced from ESCs in vitro have been reported. Furthermore, some efficient methods for inducing the useful number of germ cells from ESCs have also been developed. On the other hand, in primates, despite the appearances of germ cell-like cells including meiotic cells were observed by spontaneous differentiation or introducing transgenes, it has not been determined whether fully functional germ cells can be derived from ESCs. To elucidate the property for the germ cells induced from primate ESCs, specification of the promoting factors for the germ cell development and improving the efficiency of germ cell derivation are essential. Leukemia inhibitory factor (LIF) has been reported as one of the important factors for mouse primordial germ cell (PGC) survival in vitro. However, the effects of LIF on germ cell formation from pluripotent cells of primates have not been examined. The aim of this study is to determine whether LIF addition can improve in vitro germ cell production from cynomolgus monkey ESCs (cyESCs). After 8 days of differentiation, LIF added culture induced dome-shaped germ cell colonies as indicated by the intense expression of alkaline phosphatase activity (ALP). These cells also demonstrate high-level expression of the germ cell-marker VASA, OCT-4, and BLIMP-1, and show SSEA-1 expression that supports their early stage germ cell identity. Finally, we observed that adding LIF to differentiating cultures inhibited meiotic gene expressions and increased the percentage of ALP-positive cells, and demonstrate that the addition of LIF to differentiation media increases differentiation of early germ cells from the cyESCs.

Induction of hypertrophic chondrocyte-like phenotypes by oxidized LDL in cultured bovine articular chondrocytes through increase in oxidative stress

OBJECTIVE

It has been reported that the lectin-like oxidized low-density lipoprotein (Ox-LDL) receptor 1 (LOX-1) is expressed by chondrocytes in osteoarthritis (OA) cartilage and that Ox-LDL binding to LOX-1 increases intracellular oxidative stress in cultured bovine articular chondrocytes (BACs). It was recently demonstrated that reactive oxygen species (ROS) induce hypertrophic differentiation of chondrocytes in the growth plate. It has also been shown that activated chondrocytes in OA have hypertrophic chondrocyte-like phenotypes. The purpose of this study was to determine whether Ox-LDL induces hypertrophic chondrocyte-like phenotypes in BACs.

DESIGN

Changes in type X collagen (COL10) and runt-related transcription factor 2 (Runx2) mRNA expression in BACs after Ox-LDL stimulation were investigated using real-time polymerase chain reaction (PCR). Western blotting and immunofluorescent cell staining were used to investigate changes in protein level. The antioxidant N-acetyl cysteine (NAC) was used to ascertain whether oxidative stress is involved in COL10 and Runx2 expression. We induced LOX-1 knockdown cells using small interfering RNA (siRNA) to examine the receptor specificity of Ox-LDL.

RESULTS

COL10 expression was upregulated by Ox-LDL in a time- and dose-dependent manner. Immunofluorescent staining showed that Ox-LDL increased COL10 production in the extracellular matrix. Ox-LDL-induced upregulation of COL10 was suppressed by pretreatment with NAC and siRNA. Expression of Runx2 was upregulated by Ox-LDL and H(2)O(2), and these effects were suppressed by NAC pretreatment.

CONCLUSION

Ox-LDL binding to LOX-1 induces a hypertrophic chondrocyte-like phenotype through oxidative stress, indicating that Ox-LDL plays a role in the degeneration of cartilage.

Mouse androgenetic embryonic stem cells differentiated to multiple cell lineages in three embryonic germ layers in vitro

The embryos of some rodents and primates can precede early development without the process of fertilization; however, they cease to develop after implantation because of restricted expressions of imprinting genes. Asexually developed embryos are classified into parthenote/gynogenote and androgenote by their genomic origins. Embryonic stem cells (ESCs) derived from asexual origins have also been reported. To date, ESCs derived from parthenogenetic embryos (PgESCs) have been established in some species, including humans, and the possibility to be alternative sources for autologous cell transplantation in regenerative medicine has been proposed. However, some developmental characteristics, which might be important for therapeutic applications, such as multiple differentiation capacity and transplantability of the ESCs of androgenetic origin (AgESCs) are uncertain. Here, we induced differentiation of mouse AgESCs and observed derivation of neural cells, cardiomyocytes and hepatocytes in vitro. Following differentiated embryoid body (EB) transplantation in various mouse strains including the strain of origin, we found that the EBs could engraft in theoretically MHC-matched strains. Our results indicate that AgESCs possess at least two important characteristics, multiple differentiation properties in vitro and transplantability after differentiation, and suggest that they can also serve as a source of histocompatible tissues for transplantation.

Characteristics of prolactin-releasing response to salsolinol (SAL) and thyrotropin-releasing hormone (TRH) in ruminants

The secretion of prolactin (PRL) is stimulated by thyrotropin-releasing hormone (TRH), and inhibited by dopamine (DA). However, we have recently demonstrated that salsolinol (SAL), a DA-derived endogenous compound, is able to stimulate the release of PRL in ruminants. The aims of the present study were to compare the characteristics of the PRL-releasing response to SAL and TRH, and examine the relation between the effects that SAL and DA exert on the secretion of PRL in ruminants in vivo and in vitro. Three consecutive intravenous (i.v.) injections of SAL (5mg/kg body weight (b.w.): 19.2micromol/kgb.w.) or TRH (1microg/kgb.w.: 2.8nmol/kgb.w.) at 2-h intervals increased plasma PRL levels after each injection in goats (P<0.05); however, the responses to SAL were different from those to TRH. There were no significant differences in each peak value between the groups. The rate of decrease in PRL levels following the peak was attenuated in SAL-treated compare to TRH-treated animals (P<0.05). PRL-releasing responses to SAL were similar to those to sulpiride (a DA receptor antagonist, 0.1mg/kgb.w.: 293.3nmol/kgb.w.). In cultured bovine anterior pituitary (AP) cells, TRH (10(-8)M) significantly increased the release of PRL following both 15- and 30-min incubation periods (P<0.05), but SAL (10(-6)M) did not increase the release during the same periods. DA (10(-6)M) completely blocked the TRH-induced release of PRL for a 2-h incubation period in the AP cells (P<0.05). Sulpiride (10(-6)M) reversed this inhibitory effect but SAL (10(-6)M) did not have any influence on the action of DA. These results show that the mechanism(s) by which SAL releases PRL is different from the mechanism of action of TRH. Furthermore, they also show that the secretion of PRL is under the inhibitory control of DA, and SAL does not antagonize the DA receptor's action.

Rho-associated kinase inhibitor Y-27632 promotes survival of cynomolgus monkey embryonic stem cells

Non-human primates are suitable models for preclinical research aimed at cell-replacement therapies. Recently, it has been reported that Rho-associated kinase inhibitor Y-27632 markedly reduced dissociation-induced apoptosis of human embryonic stem (hES) cells, and is expected as a novel supplement for hES cell maintenance or differentiation inductions; however, the effects of the chemical are still to be determined in model animals. Here, we demonstrated the effect of Y-27632 on cynomolgus monkey ES (cyES) cells. Also, in cyES cells, Y-27632 treatment dramatically improved the efficiency of colony formation from single cells without affecting the pluripotent state and karyotype. Y-27632 supplementation was also effective for feeder-free culture and differentiation induction. Neural stem cells directly induced from cyES cells could give rise to neurons, astrocytes and dopamine producing cells. The present result not only suggests that the chemical was effective for improving the culture system of primate ES cells, but also the similarity between cyES and hES cells regarding the reactions to the chemical, which might be further evidence that cyES cells are superior models for hES cells.

Clinical features of chromosome 16q22.1 linked autosomal dominant cerebellar ataxia in Japanese

Chromosome 16q22.1-linked autosomal dominant cerebellar ataxia (16q-ADCA) is strongly associated with a substitution in the puratrophin-1 gene. This locus overlaps with spinocerebellar ataxia type 4 (SCA4) which shows ataxia with prominent sensory axonal neuropathy. We found that 16q-ADCA is a common ADCA subtype in the Tohoku District of Japan. The clinical feature of Japanese 16q-ADCA is characterized as late-onset pure cerebellar ataxia.

Management and algorithm for focal nodular hyperplasia of the liver in children

PURPOSE

The aim of this study was to determine an appropriate management plan for childhood and adolescent FNH, in particular to establish an algorithm for preoperative diagnosis and treatment.

PATIENTS AND METHODS

Between 1985 and 2003, 4 children with FNH were diagnosed. Of these 4 patients, 3 (Group A) underwent tumor resection, and 1 (Group B) was treated by conservative management. Clinical data, pathological findings and follow-up were evaluated retrospectively.

RESULTS

The 3 patients in Group A were symptomatic, while the 1 patient in Group B was asymptomatic. In 3 of 4 patients, a homogeneous tumor with a central stellate area was noted on abdominal ultrasonography, CT scan and MR imaging. In case 2, SPIO-enhanced MR imaging was useful for differentiating FNH from hepatocellular carcinoma. Though percutaneous needle biopsy was performed in case 3, a pathologically definitive diagnosis was impossible. An open biopsy was performed in case 4 and FNH was diagnosed. In case 4 treated by conservative management, the tumor size did not change during the 7 years after the diagnosis of FNH.

CONCLUSION

FNH is usually treated conservatively because of the good evolutionary outcome of the lesion. Surgery is indicated in cases of complications, compressed adjacent organs, lesion progression, or for symptomatic patients. We advocate the use of less invasive SPIO-enhanced MR imaging instead of open biopsy when the diagnosis of focal liver lesions is not clear after contrast-enhanced CT scan and non-enhanced MR imaging.

Endobronchial ultrasonography with guide-sheath for peripheral pulmonary lesions

The usefulness of endobronchial ultrasonography (EBUS) with guide-sheath (GS) as a guide for transbronchial biopsy (TBB) for diagnosing peripheral pulmonary lesions (PPL)s and for improving diagnostic accuracy was evaluated in this study. EBUS-GS-guided TBB was performed in 24 patients with 24 PPLs of < or =30 mm in diameter (average diameter=18.4 mm). A 20-MHz radial-type ultrasound probe, covered with GS was inserted via a working bronchoscope channel and advanced to the PPL in order to produce an EBUS image. The probe with the GS was confirmed to reach the lesion by EBUS imaging and X-ray fluoroscopy. When the lesion was not identified on the EBUS image, the probe was removed and a curette was used to lead the GS to the lesion. After localising the lesion, the probe was removed, and TBB and bronchial brushing were performed via the GS. Nineteen peripheral lesions (79.2%) were visualised by EBUS. All patients whose PPLs were visible on EBUS images subsequently underwent an EBUS-GS-guided diagnostic procedure. A total of 14 lesions (58.3%) were diagnosed. Even when restricted to PPLs <20 mm in diameter, the diagnostic sensitivity was 53%. In conclusion, endobronchial ultrasonography with guide sheath-guided transbronchial biopsy was feasible and effective for diagnosing peripheral pulmonary lesions.

Dysferlin mutations in Japanese Miyoshi myopathy: relationship to phenotype

OBJECTIVE

To study dysferlin gene mutations and genotype-phenotype correlations in Japanese patients with Miyoshi myopathy (MM).

BACKGROUND

MM is an autosomal recessive distal muscular dystrophy that arises from mutations in the dysferlin gene. This gene is also mutated in families with limb girdle muscular dystrophy 2B.

METHODS

The authors examined 25 Japanese patients with MM. Genomic DNA was extracted from the peripheral lymphocytes of the patients. The PCR products of each of 55 exons were screened by single strand conformation polymorphism or direct sequencing from the PCR fragments.

RESULTS

The authors identified 16 different mutations in 20 patients with MM; 10 were novel. Mutations in Japanese patients are distributed along the entire length of the gene.

CONCLUSIONS

Four mutations (C1939G, G3370T, 3746delG, and 4870delT) are relatively more prevalent in this population, accounting for 60% of the mutations in this study. This study revealed that the G3370T mutation was associated with milder forms of MM and the G3510A mutation was associated with a more severe form.

Oxidative stress and predominant Abeta42(43) deposition in myopathies with rimmed vacuoles

This study was undertaken to determine the C terminus of amyloid beta protein (Abeta), accumulated in vacuolated muscle fibers, and compare these findings to the level of oxidative stress. Eight patients with myopathies characterized by rimmed vacuoles (RVs) were analyzed. Monoclonal antibodies specific to Abeta40 or Abeta42(43) revealed that the Abeta42(43) immunoreactivity was solely distributed in the vacuolated muscle fibers, and that only a part was also immunopositive for anti-Abeta40. Quantitative analyses in four specimens, in which eight or more vacuolated muscle fibers were observed, revealed that the mean incidence of Abeta42(43)-positive muscle fibers was 79.5+/-6.2% in total vacuolated muscle fibers, whereas that of the Abeta40-positive fibers was 42.9+/-12.6%. The predominance of Abeta42(43) deposition was statistically significant ( P<0.05). Abeta deposition was then compared with the distribution of oxidative nucleic acid damage in muscle fibers using a monoclonal antibody against 8-hydroxy-2'-deoxyguanosine and 8-hydroxyguanosine (8OHdG&G). The cytoplasmic staining for anti-8OHdG&G was found not only in vacuolated muscle fibers, but also in other muscle fibers including morphologically normal ones. Positive staining was completely abolished by RNase pretreatment and, thus, was suggested to reflect an increase of cellular RNA oxidation. The distribution of 8OHdG&G was much broader than the Abeta deposition. These data suggest that Abeta42(43) is predominantly involved in the pathogenesis of muscle fiber degeneration with RVs, and that oxidative damage may precede Abeta deposition in muscle fibers and play a key role in the pathomechanism of myopathies with RVs.