Knockdown of LAP2α inhibits adipogenesis of human adipose-derived stem cells and ameliorates high-fat diet-induced obesity.

Adipogenesis, a pivotal cellular process involving the differentiation of mesenchymal stem cells (MSCs) to mature adipocytes, plays a significant role in various physiological functions. Dysregulation of adipogenesis is implicated in conditions such as obesity. However, the complete molecular understanding of adipogenesis remains elusive. This study aimed to uncover the novel role of lamina-associated polypeptide 2 alpha (LAP2α) in human adipose-derived stem cells (hASCs) adipogenesis and its impact on high-fat diet (HFD)-induced obesity and associated metabolic disturbances. LAP2α expression was assessed during the adipogenic differentiation of hASCs using RT-qPCR and western blotting. The functional role of LAP2α in adipogenesis was explored both in vitro and in vivo through loss- and gain-of-function studies. Moreover, mice with HFD-induced obesity received lentivirus injection to assess the effect of LAP2α knockdown on fat accumulation. Molecular mechanisms underlying LAP2α in adipogenic differentiation were investigated using RT-qPCR, Western blotting, immunofluorescence staining, and Oil Red O staining. LAP2α expression was upregulated during hASCs adipogenic differentiation. LAP2α knockdown hindered adipogenesis, while LAP2α overexpression promoted adipogenic differentiation. Notably, LAP2α deficiency resisted HFD-induced obesity, improved glucose intolerance, mitigated insulin resistance, and prevented fatty liver development. Mechanistically, LAP2α knockdown attenuated signal transducer and activator of transcription 3 (STAT3) activation by reducing the protein level of phosphorylated STAT3. A STAT3 activator (Colivelin) counteracted the negative impact of LAP2α deficiency on hASCs adipogenic differentiation. Taken together, our current study established LAP2α as a crucial regulator of hASCs adipogenic differentiation, unveiling a new therapeutic target for obesity prevention.

Multi modality fusion transformer with spatio-temporal feature aggregation module for psychiatric disorder diagnosis.

Bipolar disorder (BD) is characterized by recurrent episodes of depression and mild mania. In this paper, to address the common issue of insufficient accuracy in existing methods and meet the requirements of clinical diagnosis, we propose a framework called Spatio-temporal Feature Fusion Transformer (STF2Former). It improves on our previous work - MFFormer by introducing a Spatio-temporal Feature Aggregation Module (STFAM) to learn the temporal and spatial features of rs-fMRI data. It promotes intra-modality attention and information fusion across different modalities. Specifically, this method decouples the temporal and spatial dimensions and designs two feature extraction modules for extracting temporal and spatial information separately. Extensive experiments demonstrate the effectiveness of our proposed STFAM in extracting features from rs-fMRI, and prove that our STF2Former can significantly outperform MFFormer and achieve much better results among other state-of-the-art methods.

[Ubiquitin-specific protease 42 regulates osteogenic differentiation of human adipose-derived stem cells].

OBJECTIVE: To explore the effect of ubiquitin-specific protease 42 (USP42) on osteogenic differentiation of human adipose-derived stem cells (hASCs) in vivo and in vitro. METHODS: A combination of experiments was carried out with genetic depletion of USP42 using a lentiviral strategy. Alkaline phosphatase (ALP) staining and quantification, alizarin red S (ARS) staining and quantification were used to determine the osteogenic differentiation ability of hASCs under osteogenic induction between the experimental group (knockdown group and overexpression group) and the control group. Quantitative reverse transcription PCR (qRT-PCR) was used to detect the expression levels of osteogenesis related genes in the experimental group and control group, and Western blotting was used to detect the expression levels of osteogenesis related proteins in the experimental group and control group. Nude mice ectopic implantation experiment was used to evaluate the effect of USP42 on the osteogenic differentiation of hASCs in vivo. RESULTS: The mRNA and protein expressions of USP42 in knockdown group were significantly lower than those in control group, and those in overexpression group were significantly higher than those in control group. After 7 days of osteogenic induction, the ALP activity in the knockdown group was significantly higher than that in the control group, and ALP activity in overexpression group was significantly lower than that in control group. After 14 days of osteogenic induction, ARS staining was significantly deeper in the knockdown group than in the control group, and significantly lighter in overexpression group than in the control group. The results of qRT-PCR showed that the mRNA expression levels of ALP, osterix (OSX) and collagen type Ⅰ (COLⅠ) in the knockdown group were significantly higher than those in the control group after 14 days of osteogenic induction, and those in overexpression group were significantly lower than those in control group. The results of Western blotting showed that the expression levels of runt-related transcription factor 2 (RUNX2), OSX and COLⅠ in the knockout group were significantly higher than those in the control group at 14 days after osteogenic induction, while the expression levels of RUNX2, OSX and COLⅠ in the overexpression group were significantly lower than those in the control group. Hematoxylin-eosin staining of subcutaneous grafts in nude mice showed that the percentage of osteoid area in the knockdown group was significantly higher than that in the control group. CONCLUSION: Knockdown of USP42 can significantly promote the osteogenic differentiation of hASCs in vitro and in vivo, and overexpression of USP42 significantly inhibits in vivo osteogenic differentiation of hASCs, and USP42 can provide a potential therapeutic target for bone tissue engineering.

The application of an intraoral banana peel suturing model in surgical training of dental students.

OBJECTIVES: This study investigated the application of an intraoral banana peel suturing model in helping students to acquire intraoral surgical techniques. METHODS: This is a self-control study conducted from January 2021 to March 2021. An intraoral banana peel suturing model was implemented to provide oral suture experience for undergraduates majoring in stomatology. The sutures students placed in the model were photographed and evaluated blindly by a professional team using an established scoring system. Training scores were recorded before (training 1) and after 2 months of training (training 2). Linear regression was used to examine factors related to the scores. Suturing training was conducted in the School and Hospital of Stomatology at Peking University. A total of eighty-two students in Peking University School and Hospital of Stomatology were in their fourth pre-clinical year and followed a workshop on surgical sutures according to the curriculum. All students who should take this course were included, and the response rate was 100%. RESULTS: The mean training 2 score (23.04 ± 3.83) was higher than the mean training 1 score (13.94 ± 3.15). The training 1 score was not significantly correlated with any of the students' general characteristics. The training 2 score was correlated with the training 1 score and the cumulative duration of practice outside of class. CONCLUSION: The intraoral banana peel suturing model can be used for suture training, and dental students' suture ability was improved after using the banana peel for suture practice.

Photodynamic immunotherapy using ADU-S100-modified nanoparticles to treat triple-negative breast cancer.

Aim: STING agonists in immunotherapy show great promise and are currently in clinical trials. Combinations of STING agonists with other therapies remain underexplored. This study aimed to combine STING agonist-mediated immunotherapy with photodynamic therapy to treat breast cancer. Methods: STING agonist (ADU-S100)-functionalized porphyrin-based nanoparticles (NP-AS) were prepared and their antitumor properties in terms of cell apoptosis/necrosis and immune activation in triple-negative breast cancer were evaluated. Results: NP-AS induced tumor cell apoptosis/necrosis, activated the innate immune response and exhibited useful antitumor effects. Conclusion: NP-AS effectively treated breast cancer.

Ubiquitin modification in osteogenic differentiation and bone formation: From mechanisms to clinical significance.

The ubiquitin-proteasome system is an important pathway for mediating posttranslational modification and protein homeostasis and exerts a wide range of functions in diverse biological processes, including stem cell differentiation, DNA repair, and cell cycle regulation. Many studies have shown that ubiquitination modification plays a critical role in regulating the osteogenic differentiation of stem cells and bone formation through various mechanisms. This review summarizes current progress on the effects and mechanisms of ubiquitin modification on transcription factors and signaling pathways involved in osteogenic differentiation. Moreover, the review highlights the latest advances in the clinical application of drugs in bone tissue engineering. A thorough understanding of ubiquitin modifications may provide promising therapeutic targets for stem cell-based bone tissue engineering.

Burnout and Its Association With Competence Among Dental Interns in China.

Intern physicians are generally more burdened by stress than the general population. This cross-sectional study aimed to evaluate the current situation regarding burnout and explore its association with the self-evaluation of competence among Chinese dental interns. A self-administered anonymous survey was conducted on 91 dental interns in the Peking University School of Stomatology, from August 2019 to June 2020. It consisted of a psychological stress questionnaire, including burnout and self-evaluation of clinical competence. The Wilcoxon signed rank test was used to determine the differences between self-evaluation scores of clinical competence. Results showed average scores for emotional exhaustion, depersonalization, and personal accomplishment of 22.22 ± 9.04, 8.16 ± 5.21, and 36.08 ± 7.76, respectively. Dental clinical technology was considered more useful than other clinical competencies, and there was a correlation between its importance and the stress caused by its deficiency (r = -0.201, p = 0.056). Significant associations were found between stress due to a lack of dental clinical technology and high emotional exhaustion (r = 0.273, p < 0.05). Burnout was common among the dental interns, which may be a valuable finding. Among the six different aspects of clinical competence, "dental clinical technology" represented the most stressful item. Strengthening pre-clinical training and promptly conducting targeted training in the early clinical process may be considered as decompression measures.

Epithelial cell transforming factor ECT2 is an important regulator of DNA double-strand break repair and genome stability.

Proteins containing breast cancer type 1 (BRCA1) C-terminal domains play crucial roles in response to and repair of DNA damage. Epithelial cell transforming factor (epithelial cell transforming sequence 2 [ECT2]) is a member of the BRCA1 C-terminal protein family, but it is not known if ECT2 directly contributes to DNA repair. In this study, we report that ECT2 is recruited to DNA lesions in a poly (ADP-ribose) polymerase 1-dependent manner. Using co-immunoprecipitation analysis, we showed that ECT2 physically associates with KU70-KU80 and BRCA1, proteins involved in nonhomologous end joining and homologous recombination, respectively. ECT2 deficiency impairs the recruitment of KU70 and BRCA1 to DNA damage sites, resulting in defective DNA double-strand break repair, an accumulation of damaged DNA, and hypersensitivity of cells to genotoxic insults. Interestingly, we demonstrated that ECT2 promotes DNA repair and genome integrity largely independently of its canonical guanine nucleotide exchange activity. Together, these results suggest that ECT2 is directly involved in DNA double-strand break repair and is an important genome caretaker.

Traditional Chinese Medicine as an adjunct therapy in the treatment of idiopathic membranous nephropathy: A systematic review and meta-analysis.

BACKGROUND: Idiopathic membranous nephropathy (IMN) is one of the most common causes of nephrotic syndrome in adults involving multiple targets and factors. The effect of conservative nonimmunosuppressive or immunosuppressive therapies is unsatisfactory and with many side effects. Traditional Chinese medicine (TCM) can regulate immune function and improve kidney function. PURPOSE: To evaluate the total effective rate, curative rate, recurrence rate and adverse events of TCM alone or TCM as an adjunctive therapy for IMN. METHODS: Randomized controlled trials (RCT) comparing either TCM alone or the combination of TCM to western medicine (WM) therapies for patients with IMN were retrieved by searching English and Chinese database. Risk of bias summary was used to assess the methodological quality of eligible studies. Dichotomous data were presented using odds ratios (OR). The primary outcome measure was the total effective rate. Secondary outcomes included curative rate, recurrence rate and adverse events. RESULTS: 29 RCTs involving 1883 participants met the inclusion criteria. There was no statistically significant difference between the therapy of TCM alone and WM on the total effective rates (OR: 2.00; 95% CI: 0.80-4.98; P = 0.14) and curative rate (OR: 1.66; 95%CI: 0.66-4.22; p = 0.28). However, compared to basic treatment or immunosuppressive therapies alone, results showed that TCM as an adjunctive therapy had beneficial effects on the total effective rate (OR: 2.59; 95% CI: 1.38-4.86; P = 0.003 and OR: 3.01; 95% CI: 2.25-4.04; P < 0.00001) and curative rate (OR: 3.01; 95%CI: 1.24-7.28; p = 0.01 and OR: 1.73; 95%CI: 1.10-2.71; p = 0.02). In addition, the combination of TCM treatment could reduce the recurrence rate (OR: 0.28; 95% CI: 0.12-0.68; P = 0.004) and adverse reactions (OR: 0.38; 95% CI: 0.27-0.54; p < 0.00001). CONCLUSION: The results indicate that TCM is well-tolerated for the treatment of IMN. However, there remains a need for large-scale and high-quality trials.

Knockdown of LAP2α inhibits osteogenic differentiation of human adipose-derived stem cells by activating NF-κB.

BACKGROUND: Lamina-associated polypeptide 2α (LAP2α) is a nucleoplasmic protein that has been involved in the regulation of the cell cycle, gene transcription, and adult stem cell function. LAP2α down-regulation is linked to age-related osteoporosis and bone deformities; however, the underlying mechanisms remain obscure. The present study aimed to elucidate the function of LAP2α in the osteogenic differentiation of human adipose-derived stem cells (hASCs), which are attractive sources for bone tissue engineering. METHODS: The expression of LAP2α during the osteogenic differentiation of hASCs was detected firstly. A loss of function investigation was then carried out to characterize the function of LAP2α in osteogenic differentiation of hASCs both in vitro and in vivo. Moreover, RNA-sequences, western blotting, and confocal analyses were performed to clarify the molecular mechanism of LAP2α-regulated osteogenesis. RESULTS: We found that LAP2α expression was upregulated upon osteogenic induction. Both in vitro and in vivo experiments indicated that LAP2α knockdown resulted in impaired osteogenic differentiation of hASCs. Mechanistically, we revealed that LAP2α deficiency activated nuclear factor kappa B (NF-κB) signaling by controlling the cytoplasmic-nuclear translocation of p65. CONCLUSIONS: Collectively, our findings revealed that LAP2α functions as an essential regulator for osteogenesis of hASCs by modulating NF-κB signaling, thus providing novel insights for mesenchymal stem cell-mediated bone tissue engineering.

The ubiquitin ligase SCFFBXW7α promotes GATA3 degradation.

GATA3 is a key transcription factor in cell fate determination and its dysregulation has been implicated in various types of malignancies. However, how the abundance and function of GATA3 are regulated remains unclear. Here, we report that GATA3 is physically associated with FBXW7α, and FBXW7α destabilizes GATA3 through assembly of a SKP1-CUL1-F-box E3 ligase complex. Importantly, we showed that FBXW7α promotes GATA3 ubiquitination and degradation in a GSK3 dependent manner. Furthermore, we demonstrated that FBXW7α inhibits breast cancer cells survival through destabilizing GATA3, and the expression level of FBXW7α is negatively correlated with that of GATA3 in breast cancer samples. This study indicated that FBXW7α is a critical negative regulator of GATA3 and revealed a pathway for the maintenance of GATA3 abundance in breast cancer cells.

Protein deubiquitinase USP7 is required for osteogenic differentiation of human adipose-derived stem cells.

BACKGROUND: Human adipose-derived stem cells (hASCs) are multipotent progenitor cells with self-renewal capabilities and multilineage differentiation potential, including osteogenesis. Although protein deubiquitinases have been linked to stem cell fate determination, whether protein deubiquitination contributes to lineage commitment during osteogenic differentiation of hASCs remains to be investigated. The objective of this study was to evaluate the effects of the ubiquitin specific protease 7 (USP7) on osteogenic differentiation of hASCs. METHODS: An osteocalcin promoter driven luciferase reporter system was established to initially discover the potential association between USP7 and hASC osteogenesis. To further characterize the function of USP7 in osteogenic differentiation of hASCs, a combination of in vitro and in vivo experiments were carried out through genetic depletion or overexpression of USP7 using a lentiviral strategy. Moreover, HBX 41,108, a cyanoindenopyrazine-derived deubiquitinase inhibitor of USP7, was utilized at different doses to further examine whether USP7 regulated osteogenic differentiation of hASCs through its enzymatic activity. RESULTS: We demonstrated that USP7 depletion was associated with remarkable downregulation of the reporter gene activity. Genetic depletion of USP7 by lentiviral RNAi markedly suppressed hASC osteogenesis both in vitro and in vivo, while overexpression of USP7 enhanced the osteogenic differentiation of hASCs. Notably, chemical blockade via the small molecular inhibitor HBX 41,108 could efficiently mimic the effects of USP7 genetic depletion in a dose-dependent manner. CONCLUSIONS: Taken together, our study revealed that protein deubiquitinase USP7 is an essential player in osteogenic differentiation of hASCs through its catalytic activity, and supported the pursuit of USP7 as a potential target for modulation of hASC-based stem cell therapy and bone tissue engineering.

The X-linked deubiquitinase USP9X is an integral component of centrosome.

The X-linked deubiquitinase USP9X has been implicated in multiple pathological disorders including malignancies and X-linked intellectual disability. However, its biological function and substrate repertoire remain to be investigated. In this study, we utilized the tandem mass tag labeling assay to identify USP9X-regulated proteins and revealed that the expression of multiple genes is altered in USP9X-deficient cells. Interestingly, we showed that USP9X promotes stabilization of centrosome proteins PCM1 and CEP55 through its catalytic activity. Remarkably, we demonstrated that USP9X is physically associated and spatially co-localized with PCM1 and CEP55 in the centrosome, and we revealed that either PCM1 or CEP55 loss resulted in impairment of USP9X centrosome localization. Moreover, we showed that USP9X is required for centrosome duplication, and this effect is dependent on its catalytic activity and its N-terminal module, which is responsible for physical association of USP9X with PCM1 and CEP55. Collectively, our experiments identified USP9X as an integral component of the centrosome where it functions to stabilize PCM1 and CEP55 and promote centrosome biogenesis.

Long non-coding RNA MEG3 inhibits adipogenesis and promotes osteogenesis of human adipose-derived mesenchymal stem cells via miR-140-5p.

lncRNAs are an emerging class of regulators involved in multiple biological processes. MEG3, an lncRNA, acts as a tumor suppressor, has been reported to be linked with osteogenic differentiation of MSCs. However, limited knowledge is available concerning the roles of MEG3 in the multilineage differentiation of hASCs. The current study demonstrated that MEG3 was downregulated during adipogenesis and upregulated during osteogenesis of hASCs. Further functional analysis showed that knockdown of MEG3 promoted adipogenic differentiation, whereas inhibited osteogenic differentiation of hASCs. Mechanically, MEG3 may execute its role via regulating miR-140-5p. Moreover, miR-140-5p was upregulated during adipogenesis and downregulated during osteogenesis in hASCs, which was negatively correlated with MEG3. In conclusion, MEG3 participated in the balance of adipogenic and osteogenic differentiation of hASCs, and the mechanism may be through regulating miR-140-5p.

The effect of Nd：YAG lasers used in root canal therapy： a Meta-analysis / 口腔疾病防治

Objective @#Meta-analysis was used to assess the effect of Nd: YAG Lasers used in root canal therapy. @*Methods @# A search of literatures about clinical effect of Nd:YAG lasers in root canal therapy in PubMed, Embase, Cochrane Library, CMCC, CNKI, VIP, Wanfang databases was conducted from 1997 to 2015. The quality of included studies was stringently evaluated and data was analyzed by the RevMan 5.3 software.@*Results@#8 studies were included in the Meta-analysis. Meta-analysis results showed that the ratio of the occurrence of endodontic interappointment emergencies (EIAE) of 24 ~ 48 hours and 1 week after the therapy was significantly lower in the Nd: YAG lasers group compared with the control group (24 h: OR = 0.27, 95％CI = 0.15 ~ 0.48; 1week: OR = 0.26, 95％CI = 0.13 ~ 0.54). The six months to one year failure rate of root canal therapy was lower in Nd:YAG lasers group compared with the control group, the differences were statistically significant (OR = 0.24, 95％CI = 0.06 ~ 1.00). @*Conclusion@# The use of Nd: YAG laser in root canal therapy relieves post-treatment pain response after the therapy and also reduces the long-term failure rate of root canal treatment.

[Clinical effect of a new low-shrinkage composite on restoring dental wedge-shaped defects].

PURPOSE: To evaluate the clinical effect of a new low-shrinkage composite FiltekTM P90 on restoring dental wedge-shaped defects. METHODS: Fifty-two patients with at least two equivalent non-carious cervical lesions on bilateral teeth (180 teeth with wedge-shaped defect) were enrolled in this study. Self-control design was used in this study. The teeth were randomly divided into experimental group which were restored with low-shrinkage composite FiltekTM P90 in one side, and the control group which were filled with FiltekTM Z350 XT composite resin in the other side. The modified USPHS/Ryge criteria were used to evaluate the treatment effects 6 months and 1 year after treatment. SPSS19.0 software package was used for statistical analysis. RESULTS: The 6-months successful rate in FiltekTM P90 group was 96.55% and 95.40% in control group. The 1 year successful rate in FiltekTM P90 group was 94.05% and 90.48% in control group. There were no significant differences in main indexes, including successful rates ,retention, marginal discoloration, marginal adaptation, surface texture, color match, secondary caries and postoperative sensitivity between the 2 groups (P>0.05). CONCLUSIONS: Low-shrinkage composite FiltekTM P90 is a good choice for treating dental wedge-shaped defects.

[Establishing a luciferase reporter system to evaluate osteogenic differentiation potential of human adipose-derived stem cells].

OBJECTIVE: Human adipose-derived stem cells (hASCs) are a highly attractive source in bone tissue engineering. To generate a luciferase reporter system that could be used to quantitatively and rapidly examine osteogenic differentiation potential of human adipose-derived stem cells (hASCs) in vitro, and eventually make it possible to monitor the osteogenic differentiation of transplanted cells in vivo. METHODS: The genomic DNA harboring promotor regions of osteocalcin and DNA sequences encoding luciferase genes were amplified by PCR and cloned into the pLVX-pTRE-puro vector to generate the OC(pro)-Luc-Puro construct. Then, the OC(pro)-Luc-Puro construct together with three assistant vectors: pMDLg/pRRE, pRSV-REV, and pVSVG, were transiently transfected into HEK293T cells followed by viral supernatants collection, filtration and concentration. Next, the hASCs stably expressing luciferase reporter gene driven by osteocalcin promotor were created with the lentivirus carrying OC(pro)-Luc-Puro cassette under puromycin selection. The OC(pro)-Luc-hASCs were then cultured in the absence or presence of osteogenic differentiation medium. On the 7th and 14th days, after osteogenic induction, cellular extracts were collected and analyzed by luciferase reporter assay. Meanwhile, alizarin red staining and quantification as well as quantitative reverse transcription PCR (qRT-PCR) analysis of osteogenic associated genes osteocalcin (OC), runt-related transcription factor 2 (Runx2) and alkaline phosphatase (ALP) were used to assess the osteogenic differentiation ability of OC(pro)-Luc-hASCs. RESULTS: OC(pro)-Luc-Puro plasmid and OCpro-Luc-hASCs were successfully generated. On the 7th and 14th days after osteogenic induction, the luciferase activity of the cellular extracts from OC(pro)-Luc-hASCs was dramatically increased. Consistently, the extracellular matrix mineralization, as shown by Alizarin red S (ARS) staining and quantification was also markedly intensified and a marked increase of the mRNA expression levels of OC, Runx2 and ALP, although to variable extent, was observed upon osteogenic differentiation. These results indicated that the observations from traditional experiments examining hASCs osteogenic differentiation were largely in agreement with that of our luciferase reporter assay in OC(pro)-Luc-hASCs. CONCLUSION: We established a luciferase reporter system that could be used to rapidly, quantitatively and specifically determine osteogenic differentiation ability of hASCs. Comparing with the traditional time-consuming methods, the system we generated here was highly effective. This system not only can be used to examine ostogenic differentiation of hASCs in a high throughput manner, but also provides a way to monitor ostogenic differentiation of cells in vivo.

Lysine-specific demethylase 1 inhibitor rescues the osteogenic ability of mesenchymal stem cells under osteoporotic conditions by modulating H3K4 methylation.

Bone tissue engineering may be hindered by underlying osteoporosis because of a decreased osteogenic ability of autologous seed cells and an unfavorably changed microenvironment in these patients. Epigenetic regulation plays an important role in the developmental origins of osteoporosis; however, few studies have investigated the potential of epigenetic therapy to improve or rescue the osteogenic ability of bone marrow mesenchymal stem cells (BMMSCs) under osteoporotic conditions. Here, we investigated pargyline, an inhibitor of lysine-specific demethylase 1 (LSD1), which mainly catalyzes the demethylation of the di- and mono-methylation of H3K4. We demonstrated that 1.5 mmol·L-1 pargyline was the optimal concentration for the osteogenic differentiation of human BMMSCs. Pargyline rescued the osteogenic differentiation ability of mouse BMMSCs under osteoporotic conditions by enhancing the dimethylation level of H3K4 at the promoter regions of osteogenesis-related genes. Moreover, pargyline partially rescued or prevented the osteoporotic conditions in aged or ovariectomized mouse models, respectively. By introducing the concept of epigenetic therapy into the field of osteoporosis, this study demonstrated that LSD1 inhibitors could improve the clinical practice of MSC-based bone tissue engineering and proposes their novel use to treat osteoporosis.

The epigenetic promotion of osteogenic differentiation of human adipose-derived stem cells by the genetic and chemical blockade of histone demethylase LSD1.

Human adipose-derived stem cells (hASCs) are a highly attractive source in bone tissue engineering. It has become increasingly clear that chromatin regulators play an important role in cell fate determination. However, how osteogenic differentiation of hASCs is controlled by epigenetic mechanisms is not fully understood. Here we use genetic tools and chemical inhibitors to modify the epigenetic program of hASCs and identify lysine-specific demethylase 1 (LSD1), a histone demethylase that specifically catalyzes demethylation of di- and mono- methyl histone H3 lysine 4 (H3K4me2/1), as a key regulator in osteogenic differentiation of hASCs. Specifically, we demonstrated that genetic depletion of LSD1 with lentiviral strategy for gene knockdown promoted osteogenic differentiation of hASCs by cell studies and xenograft assays. At the molecular level, we found that LSD1 regulates osteogenesis-associated genes expression through its histone demethylase activity. Significantly, we demonstrated LSD1 demethylase inhibitors could efficiently block its catalytic activity and epigenetically boost osteogenic differentiation of hASCs. Altogether, our study defined the functional and biological roles of LSD1 and extensively explored the effects of its enzymatic activity in osteogenic differentiation of hASCs. A better understanding of how LSD1 influences on osteogenesis associated epigenetic events will provide new insights into the modulation of hASCs based cell therapy and improve the development of bone tissue engineering with epigenetic intervention.

[Osteogenic capability of primary human adipose-derived stromal cells in vivo].

OBJECTIVE: To investigate the osteogenic capability of primary human adipose-derived stromal cells (hASCs) in vivo. METHODS: hASCs were isolated from adipose tissue by the method of collagenase digestion. After 7 and 14 days of osteogenic induction, alkaline phosphatase (ALP) staining and Alizarin Red staining were performed to test the osteogenic potential of hASCs in vitro. After 14 days of adipogenic induction, the adipogenic potential of hASCs was assayed by Oil Red O staining.In the in vivo part, 12 nude mice were used. Test group (scaffold with hASCs) and control group (scaffold only) were symmetrically implanted into the back of nude mice. After 4 weeks and 8 weeks of implantation, samples were collected. Histological and immunohistochemical staining were performed to investigate the osteogenic capability of hASCs. RESULTS: Approximately 6×10(7) hASCs could be isolated from 300 mL adipose tissue. ALP, Alizarin Red and Oil Red O staining of hASCs showed positive results after specific inductions. These results demonstrated the osteogenic and adipogenic potentials of hASCs in vitro. Bone-like tissue could be observed in the test group at 4 weeks and 8 weeks after the implantation. Immunohistochemical staining showed that there were positive results of osteocalcin, ALP and anti-human nuclei in the bone-like tissue areas. CONCLUSION: A large number of primary hASCs can be isolated from human adipose tissue; hASCs combined with scaffold show osteogenic capability in vivo.