Three-Dimensional Culture of Salivary Gland Stem Cell in Orthotropic Decellularized Extracellular Matrix Hydrogels.

Radiotherapy in patients with cancer can kill cancer cells but also damage normal cells or tissues. During the treatment of patients with head and neck cancer or thyroid cancer, hyposalivation is a representative chronic side effect of radio-damaged salivary glands (SGs). The major symptom of hyposalivation is mouth dryness, resulting in several subsequent long-term complications. No effective therapeutic approaches have been developed to manage this symptom. In this study, we developed the first rat SG tissue-derived decellularized extracellular matrix hydrogel (DSGM-hydrogel) as a functional orthotropic bioscaffold for future efficient SG stem cell therapy. DSGM-hydrogels were characterized by rheological or biochemical analyses, and rat SG stem/progenitor cells (rSGSCs) were then subjected to three-dimensional culture in the DSGM-hydrogels. Interestingly, DSGM-hydrogel-embedded rSGSCs survived and expressed SG functional differentiation marker of amylase IA and increased enzyme activity of α-amylase in protein level, whereas they showed reduced levels of adult ductal stem/progenitor markers, including c-Kit, c-Met, and CD44. Furthermore, the expression levels of basic epithelial tight junction markers were recovered to levels similar to those naked SG tissues after culture in DSGM-hydrogels in transcription level. Therefore, our findings suggested that the DSGM-hydrogels could provide an appropriate microenvironment for stem/progenitor cell survival and a source of SG cytodifferentiation. This approach could be an applicable method to SG stem cell research as a potential source for an organoid and for clinical regenerative reagents to manage radio-damaged SGs in vivo. Impact Statement In this study, we established the first rat salivary gland (SG) tissue-derived decellularized extracellular matrix hydrogel (DSGM-hydrogel) and assessed the role of this hydrogel as a functional orthotropic bioscaffold. Our findings provide important insights into the applications of the DSGM-hydrogel as a biocompatible matrix for regenerative therapy of radio-damaged SGs.

Detection of Methylated SEPT9 in Korean Colorectal Cancer Patients: Comparison with Previous Studies.

BACKGROUND: This study aimed to investigate the detection of methylated Septin 9 (mSEPT9) in Korean patients with colorectal cancer (CRC) and compare the results with those of previous studies. METHODS: A total of 127 plasma samples (111 patients with untreated CRC, 5 patients with adenomas, and 11 CRC patients treated with concurrent chemoradiotherapy before surgery) were collected. mSEPT9 was measured qualitatively with the Abbott RealTime ms9 Colorectal Cancer Assay. RESULTS: mSEPT9 was detected in 44 of 111 (39.6%) cases of untreated CRC but was not detected in the adenoma cases. The difference in the sensitivity of mSEPT9 among patients with adenomas and those with each stage of untreated CRC was statistically significant (Dukes' staging, p = 0.002 and TNM staging, p = 0.008). The sensitivity of mSEPT9 for each of the stages (I - IV) of untreated CRC patients were 20.7%, 54.1%, 36.6%, and 75.0%, respectively. The positive mSEPT9 results in untreated CRC patients reverted to negative in 19 of 21 patients (90.5%) after treatment. CONCLUSIONS: Compared to previous studies, the overall sensitivity of mSEPT9 was lower, but similar patterns were found in the sensitivities for each stage. Additionally, mSEPT9 appeared to have potential as a monitoring tool for CRC.

Fbxw7ß is an inducing mediator of dexamethasone-induced skeletal muscle atrophy in vivo with the axis of Fbxw7ß-myogenin-atrogenes.

Muscle atrophy is induced by several pathways, e.g., it can be attributed to inherited cachectic symptoms, genetic disorders, sarcopenia, or chronic side effects of treatments. However, the underlying regulatory mechanisms that contribute to muscle atrophy have not been fully elucidated. In this study, we evaluated the role of Fbxw7ß, an ubiquitin E3 ligase, in a dexamethasone-induced muscle atrophy model. In this model, endogenous Fbxw7ß was up-regulated; furthermore, the Fbxw7ß-myogenin-atrogene axis was upregulated, supporting our previous results linking Fbxw7ß to muscle atrophy in vitro. Also, muscle atrophy was associated with the Fbxw7ß-myogenin-atrogene axis and the down-regulation of Dach2, a repressor of myogenin. Taken together, these results suggest that the ubiquitin E3 ligase Fbxw7ß and the Fbxw7ß-myogenin-atrogene axis have important roles in a dexamethasone-induced muscle atrophy model in vivo and in vitro. Additionally, the Fbxw7ß-Dach2-myogenin-atrogene axis is a potential mechanism underlying muscle atrophy in cases of abnormal Fbxw7ß expression-induced muscle atrophy or myogenic degenerative disease.

Skeletal muscle atrophy is induced by Fbxw7ß via atrogene upregulation.

Muscle atrophy decreases skeletal muscle mass and is induced by inherited cachectic symptoms, genetic disorders, and sarcopenia. However, the molecular pathways associated with the onset of muscle atrophy are still unclear. In this study, we evaluated Fbxw7ß, a gene associated with the development of muscle atrophy in vitro and in vivo. Among the three Fbxw7 isoforms, ectopically overexpressed Fbxw7ß induced the expression of myogenin and major atrogene markers (atrogin-1 and MuRF-1) and reduced myoblast differentiation. In addition, endogenous expression of Fbxw7ß was also upregulated by dexamethasone, which mimics muscle atrophy in vitro, accompanied by induction of myogenin and atrogene expression in primary myoblasts. Functional analysis of Fbxw7ß using short hairpin RNA (shRNA) and a dominant-negative mutant (ΔFbox) suggested that Fbxw7ß regulated muscle atrophy in vitro and in vivo. In particular, ΔFbox did not reduce the sizes of muscle fibers and did not induce myogenin and atrogene expression in vivo. Therefore, our findings demonstrated, for the first time, that Fbxw7ß induced muscle atrophic phenotypes via atrogenes in adult muscle precursor cells and myofibers; this mechanism could be a potential therapeutic target for skeletal muscle atrophy.

Fbxw7ß, E3 ubiquitin ligase, negative regulation of primary myoblast differentiation, proliferation and migration.

Satellite cells attached to skeletal muscle fibers play a crucial role in skeletal muscle regeneration. During regeneration, the satellite cells proliferate, migrate to the damaged region, and fuse to each other. Although it is important to determine the cellular mechanisms controlling myoblast behavior, their regulators are not well understood. In this study, we evaluated the roles of Fbxw7 in primary myoblasts and determined its potential as a therapeutic target for muscle disease. We originally found that Fbxw7ß, one of the E3 ubiquitin ligase Fbxw7 subtypes, negatively regulates differentiation, proliferation and migration of myoblasts and satellite cells on muscle fiber. However, these phenomena were not observed in myoblasts expressing a dominant-negative, F-box deleted Fbxw7ß, mutant. Our results suggest that myoblast differentiation potential and muscle regeneration can be regulated by Fbxw7ß.

Patient-tailored application for Duchene muscular dystrophy on mdx mice based induced mesenchymal stem cells.

Mesenchymal stem cells (MSCs) may be used as powerful tools for the repair and regeneration of damaged tissues. However, isolating tissue specific-derived MSCs may cause pain and increased infection rates in patients, and repetitive isolations may be required. To overcome these difficulties, we have examined alternative methods for MSC production. Here, we show that induced pluripotent stem cells (iPSCs) may be differentiated into mesenchymal stem cells (iMSCs) following exposure to SB431542. Purified iMSCs were administered to mdx mice to study skeletal muscle regeneration in a murine model of muscular dystrophy. Purified iMSCs displayed fibroblast-like morphology, formed three-dimensional spheroid structures, and expressed characteristic mesenchymal stem cell surface markers such as CD29, CD33, CD73, CD90, and CD105. Moreover, iMSCs were capable of differentiating into adipogenic, osteogenic, and chondrogenic lineages. Transplanting iMSC cells to tibialis anterior skeletal muscle tissue in mdx mice lowered oxidative damage as evidenced by a reduction in nitrotyrosine levels, and normal dystrophin expression levels were restored. This study demonstrates the therapeutic potential of purified iMSCs in skeletal muscle regeneration in mdx mice, and suggests that iPSCs are a viable alternate source for deriving MSCs as needed.