Lysine 2-hydroxyisobutyrylation levels determined adipogenesis and fat accumulation in adipose tissue in pigs

Background Excessive backfat deposition lowering carcass grade is a major concern in the pig industry,especially in most breeds of obese type pigs.The mechanisms involved in adipogenesis and fat accumulation in pigs remain unclear.Lysine 2-hydroxyisobutyrylation(Khib),is a novel protein post-translational modification(PTM),which play an important role in transcription,energy metabolism and metastasis of cancer cells,but its role in adipogenesis and fat accumulation has not been shown.Results In this study,we first analyzed the modification levels of acetylation(Kac),Khib,crotonylation(Kcr)and succinylation(Ksu)of fibro-adipogenic progenitors(FAPs),myogenic precursors(Myo)and mesenchymal stem cells(MSCs)with varied differentiation potential,and found that only Khib modification in FAPs was significantly higher than that in MSCs.Consistently,in parallel with its regulatory enzymes lysine acetyltransferase 5(KAT5)and histone deacetylase 2(HDAC2)protein levels,the Khib levels increased quadratically(P<0.01)during adipogenic differentiation of FAPs.KAT5 knockdown in FAPs inhibited adipogenic differentiation,while HDAC2 knockdown enhanced adipogenic differentiation.We also demonstrated that Khib modification favored to adipogenic differentiation and fat accumulation by comparing Khib levels in FAPs and backfat tissues both derived from obese-type pigs(Laiwu pigs)and lean-type pigs(Duroc pigs),respectively.Accordingly,the expression patterns of KAT5 and HDAC2 matched well to the degree of backfat accumulation in obese-and lean-type pigs.Conclusions From the perspective of protein translational modification,we are the first to reveal the role of Khib in adipogenesis and fat deposition in pigs,and provided new clues for the improvement of fat accumulation and distribution as expected via genetic selection and nutritional strategy in obese-type pigs.

Sinomenine increases osteogenesis in mice with ovariectomyinduced bone loss by modulating autophagy

BACKGROUND A decreased autophagic capacity of bone marrow mesenchymal stromal cells(BMSCs)has been suggested to be an important cause of decreased osteogenic differentiation.A pharmacological increase in autophagy of BMSCs is a potential therapeutic option to increase osteoblast viability and ameliorate osteoporosis.AIM To explore the effects of sinomenine(SIN)on the osteogenic differentiation of BMSCs and the underlying mechanisms.METHODS For in vitro experiments,BMSCs were extracted from sham-treated mice and ovariectomized mice,and the levels of autophagy markers and osteogenic differentiation were examined after treatment with the appropriate concen-trations of SIN and the autophagy inhibitor 3-methyladenine.In vivo,the therapeutic effect of SIN was verified by establishing an ovariectomy-induced mouse model and by morphological and histological assays of the mouse femur.RESULTS SIN reduced the levels of AKT and mammalian target of the rapamycin(mTOR)phosphorylation in the phosphatidylinositol 3-kinase(PI3K)/AKT/mTOR signaling pathway,inhibited mTOR activity,and increased autophagy ability of BMSCs,thereby promoting the osteogenic differentiation of BMSCs and effectively alleviating bone loss in ovariectomized mice in vivo.CONCLUSION The Chinese medicine SIN has potential for the treatment of various types of osteoporosis,bone homeostasis disorders,and autophagy-related diseases.

Case Report and Clinical Management of a Case of Osteogenesis Imperfecta Detected in the Prenatal Period

Osteogenesis imperfecta is a hereditary disease characterized by bone fragility due to a defect in type I collagen synthesis. The diagnosis is typically suspected based on suggestive ultrasound findings and confirmed through genetic studies. We present a case of osteogenesis imperfecta suspected during obstetrical ultrasound at 19 weeks’ gestation, which was later confirmed radiographically through computed tomography. Due to the severity of the condition, therapeutic termination of pregnancy was indicated.

The flavonoid glycoside vaccarin inhibits adipogenesis and stimulates lipolysis via Hedgehog signaling in 3T3-L1 adipocytes

Vaccarin,a flavonoid glycoside isolated from Vaccaria segetalis,is non-toxic to 3T3-L1 cells up to concentrations of 200μM.Accordingly,we investigated the effects of this natural product on adipogenesis and lipolysis in 3T3-L1 adipocytes.Our results revealed that vaccarin significantly inhibited lipid accumulation by suppressing the adipogenesis-related transcription factors peroxisome proliferator-activated receptorγ(PPARγ)and the CCAAT/enhancer-binding proteinα(C/EBPα).Specifically,lipid accumulation decreased by up to 27.7±2.7%when 3T3-L1 adipocytes were treated with a 10μM concentration of vaccarin.Mechanistic studies showed that the compound inhibited adipogenesis through activation of the Hedgehog(Hh)signaling pathway and so restoring Smo and Gli1 expression at an early stage of differentiation.In mature 3T3-L1 cells,vaccarin significantly increased the secretion of glycerol into the surrounding medium and thus indicating that it accelerated the degradation of triglycerides.In addition,vaccarin,was shown to enhance lipolysis through stimulation of the transcription levels of lipoprotein lipase,monoglycerides lipase,adipose triacylglyceride lipase,hormone-sensitive lipase and adipose differentiated-related protein.All told,vaccarin suppressed lipid accumulation and enhanced lipolysis during adipocyte differentiation by restoring Hh signaling.As such,it is a phytochemical capable of halting adipocyte hyperplasia and,thereby,ameliorating the effects of obesity.

RNA-seq analysis reveals the critical role of the novel lnc RNA BIANCR in intramuscular adipogenesis through the ERK1/2 signaling pathway

Background Long non-coding RNAs(lncRNAs)regulate numerous biological processes,including adipogenesis.Research on adipogenesis will assist in the treatment of human metabolic diseases and improve meat quality in livestock,such as the content of intramuscular fat(IMF).However,the significance of lncRNAs in intramuscular adipogenesis remains unclear.This research aimed to reveal the lncRNAs transcriptomic profiles in the process of bovine intramuscular adipogenesis and to identify the lncRNAs involved in the adipogenesis of bovine intramuscular adipocytes.Results In this research,a landscape of lncRNAs was identified with RNA-seq in bovine intramuscular adipocytes at four adipogenesis stages(0 d,3 d,6 d,and 9 d after differentiation).A total of 7035 lncRNAs were detected,including 3396 novel lncRNAs.Based on the results of differential analysis,co-expression analysis,and functional prediction,we focused on the bovine intramuscular adipogenesis-associated long non-coding RNA(BIANCR),a novel lncRNA that may have an important regulatory function.The knockdown of BIANCR inhibited proliferation and promoted apoptosis of intramuscular preadipocytes.Moreover,BIANCR knockdown inhibited intramuscular adipogenesis by regulating the ERK1/2 signaling pathway.Conclusion This study obtained the landscape of lncRNAs during adipogenesis in bovine intramuscular adipocytes.BIANCR plays a crucial role in adipogenesis through the ERK1/2 signaling pathway.The results are noteworthy for improving beef meat quality,molecular breeding,and metabolic disease research.

Super enhancers targeting ZBTB16 in osteogenesis protect against osteoporosis

As the major cell precursors in osteogenesis, mesenchymal stem cells(MSCs) are indispensable for bone homeostasis and development. However, the primary mechanisms regulating osteogenic differentiation are controversial. Composed of multiple constituent enhancers, super enhancers(SEs) are powerful cis-regulatory elements that identify genes that ensure sequential differentiation. The present study demonstrated that SEs were indispensable for MSC osteogenesis and involved in osteoporosis development. Through integrated analysis, we identified the most common SE-targeted and osteoporosis-related osteogenic gene,ZBTB16. ZBTB16, positively regulated by SEs, promoted MSC osteogenesis but was expressed at lower levels in osteoporosis.Mechanistically, SEs recruited bromodomain containing 4(BRD4) at the site of ZBTB16, which then bound to RNA polymerase IIassociated protein 2(RPAP2) that transported RNA polymerase Ⅱ(POL Ⅱ) into the nucleus. The subsequent synergistic regulation of POL Ⅱ carboxyterminal domain(CTD) phosphorylation by BRD4 and RPAP2 initiated ZBTB16 transcriptional elongation, which facilitated MSC osteogenesis via the key osteogenic transcription factor SP7. Bone-targeting ZBTB16 overexpression had a therapeutic effect on the decreased bone density and remodeling capacity of Brd4^(fl/fl)Prx1-cre mice and osteoporosis(OP) models.Therefore, our study shows that SEs orchestrate the osteogenesis of MSCs by targeting ZBTB16 expression, which provides an attractive focus and therapeutic target for osteoporosis.

Zuo Gui Wan Promotes Osteogenesis via PI3K/AKT Signaling Pathway:Network Pharmacology Analysis and Experimental Validation

Objective Osteogenesis is vitally important for bone defect repair,and Zuo Gui Wan(ZGW)is a classic prescription in traditional Chinese medicine(TCM)for strengthening bones.However,the specific mechanism by which ZGW regulates osteogenesis is still unclear.The current study is based on a network pharmacology analysis to explore the potential mechanism of ZGW in promoting osteogenesis.Methods A network pharmacology analysis followed by experimental validation was applied to explore the potential mechanisms of ZGW in promoting the osteogenesis of bone marrow mesenchymal stem cells(BMSCs).Results In total,487 no-repeat targets corresponding to the bioactive components of ZGW were screened,and 175 target genes in the intersection of ZGW and osteogenesis were obtained.And 28 core target genes were then obtained from a PPI network analysis.A GO functional enrichment analysis showed that the relevant biological processes mainly involve the cellular response to chemical stress,metal ions,and lipopolysaccharide.Additionally,KEGG pathway enrichment analysis revealed that multiple signaling pathways,including the phosphatidylinositol-3-kinase/protein kinase B(PI3K/AKT)signaling pathway,were associated with ZGW-promoted osteogensis.Further experimental validation showed that ZGW could increase alkaline phosphatase(ALP)activity as well as the mRNA and protein levels of ALP,osteocalcin(OCN),and runt related transcription factor 2(Runx 2).What’s more,Western blot analysis results showed that ZGW significantly increased the protein levels of p-PI3K and p-AKT,and the increases of these protein levels significantly receded after the addition of the PI3K inhibitor LY294002.Finally,the upregulated osteogenic-related indicators were also suppressed by the addition of LY294002.Conclusion ZGW promotes the osteogenesis of BMSCs via PI3K/AKT signaling pathway.

m^(6)A demethylase FTO regulate CTNNB1 to promote adipogenesis of chicken preadipocyte

Background:N6-methyladenosine(m^(6)A)is an abundant post-transcriptional RNA modification that affects various biological processes.The fat mass and obesity-associated(FTO)protein,a demethylase encoded by the FTO gene,has been found to regulate adipocyte development in an m^(6)A-dependent manner in multiple species.However,the effects of the m^(6)A methylation and FTO demethylation functions on chicken adipogenesis remain unclear.This study aims to explore the association between m^(6)A modification and chicken adipogenesis and the underlying mechanism by which FTO affects chicken preadipocyte development.Results:The association between m^(6)A modification and chicken lipogenesis was assessed by treating chicken pread-ipocytes with different doses of methyl donor betaine and methylation inhibitor cycloleucine.The results showed that betaine significantly increased methylation levels and inhibited lipogenesis,and the inverse effect was found in preadipocytes after cycloleucine treatment.Overexpression of FTO significantly inhibited m^(6)A levels and promoted proliferation and differentiation of chicken preadipocytes.Silencing FTO showed opposite results.Mechanistically,FTO overexpression increased the expression of catenin beta 1(CTNNB1)by improving RNA stability in an m^(6)A-dependent manner,and we proved that FTO could directly target CTNNB1.Furthermore,CTNNB1 may be a positive regulator of adipogenesis in chicken preadipocytes.Conclusions:m^(6)A methylation of RNA was negatively associated with adipogenesis of chicken preadipocytes.FTO could regulate CTNNB1 expression in a demethylation manner to promote lipogenesis.

Incorporation of Mg-phenolic networks as a protective coating for magnesium alloy to enhance corrosion resistance and osteogenesis in vivo

Magnesium(Mg) and its alloys have been intensively studied to develop the next generation of bone implants recently, but their clinical application is restricted by rapid degradation and unsatisfied osteogenic effect in vivo. A bioactive chemical conversion Mg-phenolic networks complex coating(e EGCG) was stepwise incorporated by epigallocatechin-3-gallate(EGCG) and exogenous Mg^(2+)on Mg-2Zn magnesium alloy. Simplex EGCG induced chemical conversion coating(c EGCG) was set as compare group. The in vitro corrosion behavior of Mg-2Zn alloy, c EGCG and e EGCG was evaluated in SBF using electrochemical(PDP, EIS) and immersion test. The cytocompatibility was investigated with rat bone marrow mesenchymal stem cells(r BMSCs). Furthermore, the in vivo tests using a rabbit model involved micro computed tomography(Micro-CT) analysis, histological observation, and interface analysis. The results showed that the e EGCG is Mgphenolic multilayer coating incorporated Mg-phenolic networks, which is rougher, more compact and much thicker than c EGCG. The e EGCG highly improved the corrosion resistance of Mg-2Zn alloy, combined with its lower average hemolytic ratios, continuous high scavenging effect ability and relatively moderate contact angle features, resulting in a stable and suitable biological environment, obviously promoted r BMSCs adhesion and proliferation. More importantly, Micro-CT, histological and interface elements distribution evaluations all revealed that the e EGCG effectively inhibited degradation and enhanced bone tissue formation of Mg alloy implants. This study puts forward a promising bioactive chemical conversion coating with Mg-phenolic networks for the application of biodegradable orthopedic implants.

Classification of osteogenesis imperfecta:Importance for prophylaxis and genetic counseling

Osteogenesis imperfecta(OI)is a genetically heterogeneous monogenic disease characterized by decreased bone mass,bone fragility,and recurrent fractures.The phenotypic spectrum varies considerably ranging from prenatal fractures with lethal outcomes to mild forms with few fractures and normal stature.The basic mechanism is a collagen-related defect,not only in synthesis but also in folding,processing,bone mineralization,or osteoblast function.In recent years,great progress has been made in identifying new genes and molecular mechanisms underlying OI.In this context,the classification of OI has been revised several times and different types are used.The Sillence classification,based on clinical and radiological characteristics,is currently used as a grading of clinical severity.Based on the metabolic pathway,the functional classification allows identifying regulatory elements and targeting specific therapeutic approaches.Genetic classification has the advantage of identifying the inheritance pattern,an essential element for genetic counseling and prophylaxis.Although genotype-phenotype correlations may sometimes be challenging,genetic diagnosis allows a personalized management strategy,accurate family planning,and pregnancy management decisions including options for mode of delivery,or early antenatal OI treatment.Future research on molecular pathways and pathogenic variants involved could lead to the development of genotype-based therapeutic approaches.This narrative review summarizes our current understanding of genes,molecular mechanisms involved in OI,classifications,and their utility in prophylaxis.

Osteogenesis Imperfecta: One Disease, Two or More Faces: A Case Report

Being such a rare condition in paediatrics, osteogenesis imperfecta (OI) is not a diagnosis which is made often. It is however, a diagnosis necessitating early diagnosis and timeous and effective management to improve morbidity and increase the quality of life for our patients. We report two cases of osteogenesis imperfecta in this case report to highlight the different phenotypic presentations. Both of these patients are unique in their presentations and each case highlights the importance of a high clinical index of suspicion by the practitioner in making the diagnosis of osteogenesis imperfecta. The first case is a patient who was diagnosed with osteogenesis imperfecta on day one of life. She had disproportionate short stature, blue sclera, a small chest and bowing of her lower limbs with swellings and tenderness over both of her femurs. A babygram radiograph revealed multiple fractures, with the presence of callus formation at some fracture sites suggesting intrauterine fractures. The second case is a patient who had normal anthropometry and was well at birth. She was subsequently diagnosed at two weeks of age when she presented to the Chris Hani Baragwanath Academic Hospital with an E. coli meningitis and she was suspected to have a right clavicular fracture and possibly rib fractures as she had pain on palpation over these areas. She was noted to have no blue sclera. Subsequent X-rays confirmed a right clavicular fracture as well as left and right rib fractures at different stages of healing. A lateral skull radiograph revealed Wormian bones. With no available genetic testing in South Africa, both diagnoses were made clinically. Both of our patients were started on zoledronic acid at three months of age and were followed up by the Metabolic Unit at the Chis Hani Baragwanath Academic Hospital. This case report of two patients highlights the characteristics important in diagnosing and treating this uncommon condition with varying phenotypical presentations, thus ensuring that the diagnosis is not missed or misdiagnosed: one disorder, two different faces.

Expression of Bone-related Genes in Bone Marrow MSCs after Cyclic Mechanical Strain: Implications for Distraction Osteogenesis

Aim Understanding the response of mesenchymal stem cells （MSCs） to mechanical strain and their consequent gene expression patterns will broaden our knowledge of the mechanobiology of distraction osteogenesis. Methodology In this study, a single period of cyclic mechanical stretch （0.5 Hz, 2,000 με） was performed on rat bone marrow MSCs. Cellular proliferation and alkaline phosphatase （ALP） activity was examined. The mRNA expression of six bone-related genes （Ets-1, bFGF, IGF-Ⅱ, TGF-β, Cbfal and ALP） was detected using real-time quantitative RT-PCR. Results The results showed that mechanical strain can promote MSCs proliferation, increase ALP activity, and up-regulate the expression of these genes. A significant increase in Ets-1 expression was detected immediately after mechanical stimulation, but Cbfal expression became elevated later. The temporal expression pattem of ALP coincided perfectly with Cbfal. Conclusion The results of this study suggest that mechanical strain may act as a stimulator to induce differentiation of MSCs into osteoblasts, and that these bone-related genes may play different roles in the response of MSCs to mechanical stimulation.

YAP promotes osteogenesis and suppresses adipogenic differentiation by regulatingβ-catenin signaling

YAP（yes-associated protein） is a transcriptional factor that is negatively regulated by Hippo pathway, a conserved pathway for the development and size control of multiple organs. The exact function of YAP in bone homeostasis remains controversial. Here we provide evidence for YAP＇s function in promoting osteogenesis, suppressing adipogenesis, and thus maintaining bone homeostasis.YAP is selectively expressed in osteoblast（OB）-lineage cells. Conditionally knocking out Yap in the OB lineage in mice reduces cell proliferation and OB differentiation and increases adipocyte formation, resulting in a trabecular bone loss. Mechanistically, YAP interacts with β-catenin and is necessary for maintenance of nuclear β-catenin level and Wnt/β-catenin signaling. Expression of β-catenin in YAP-deficient BMSCs（bone marrow stromal cells） diminishes the osteogenesis deficit. These results thus identify YAP-β-catenin as an important pathway for osteogenesis during adult bone remodeling and uncover a mechanism underlying YAP regulation of bone homeostasis.

Osteogenesis of Adipose-Derived Stem Cells

Current treatment options for skeletal repair, including immobilization, rigid fixation, alloplastic materials and bone grafts, have significant limitations. Bone tissue engineering offers a promising method for the repair of bone deficieny caused by fractures, bone loss and tumors. The use of adipose derived stem cells （ASCs） has received attention because of the self-renewal ability, high proliferative capacity and potential of osteogenic differentiation in vitro and in vivo studies of bone regeneration. Although cell therapies using ASCs are widely promising in various clinical fields, no large human clinical trials exist for bone tissue engineering. The aim of this review is to introduce how they are harvested, examine the characterization of ASCs, to review the mechanisms of osteogenic differentiation, to analyze the effect of mechanical and chemical stimuli on ASC osteodifferentiation, to summarize the current knowledge about usage of ASC in vivo studies and clinical trials, and finally to conclude with a general summary of the field and comments on its future direction.

Electromagnetic Field Change the Expression of Osteogenesis Genes in Murine Bone Marrow Mesenchymal Stem Cells

In order to identify the differentially expressing gene of bone marrow mesenchymal stem cells （MSCs） stimulated by electromagnetic field （EMF） with osteogenesis microarray analysis, the bone marrow MSCs of SD rats were isolated and cultured in vitro. The third-passage cells were stimulated by EMFs and total RNA was extracted, purified and then used for the synthesis of cDNA and cRNA. The cRNA of stimulated group and the control group was hybridized with the rat oligo osteogenesis microarray respectively. The hybridization signals were acquired by using X-ray film after chemiluminescent detection and the data obtained were analyzed by employing the web-based completely integrated GEArray Expression Analysis Suite. RT-PCR was used to identify the target genes： Bmp1, Bmp7, Egf and Egfr. The results showed that 19 differentially expressing genes were found between the stimulated group and the control group. There were 6 up-regulated genes and 13 down-regulated genes in the stimulated group. Semi-quantitative RT-PCR confirmed that the expressions of Bmpl, Bmp7 mRNA of the stimulated group were up-regulated （P〈0.05） and those of Egf, Egfr were down-regulated （P〈0.05）. It was suggested that the gene expression profiles of osteogenesis of the bone marrow MSCs were changed after EMF treatment. It is concluded that the genes are involved in skeletal development, bone mineral metabolism, cell growth and differentiation, cell adhesion etc.

Experimental Research on Ectopic Osteogenesis of BMP2-derived Peptide P24 Combined with PLGA Copolymers

To experimentally evaluate the ectopic osteogenetic capacity of synthesized BMP2-derived peptide P24 combined with poly lactic-co-glycolic acid （PLGA）, Wistar rats were divided into two groups： group A, in which BMP2-derived peptide P24/PLGA complex was implanted, and group B which received simple PLGA implant. The complex was respectively implanted into the back muscles of rats. Samples were taken the 1st, 4th, 8th, and the 12th week after the implantation. Their bone formation was detected by X-ray examination, and tissue response was histologically observed. Western blotting was used for the detection of the expression of collagen Ⅰ （Col- Ⅰ ） and osteopontin （OPN）. There was acute inflammation in the tissue around both types of implants at early stage. The cartilage was found around implant areas 4 weeks after the implantation of BMP2-derived peptide p24/PLGA complex, 8 weeks after the implantation, osteoblasts were found, and 12 weeks after the implantation, typical trabecular bone structure was observed. In group B, after 12 weeks, no osteoblasts were found. It is concluded that PLGA is an ideal scaffold material for bone tissue engineering. BMP2-derived peptide can start endochondral ossification and is more effective in inducing ectopic osteogenesis.

Three Important Transcription Factors Related to Lipogenesis and Adipogenesis in Mammal

Lipid metabolism and adipocyte differentiation are reglulated by networking of transcription factors. It is generally known that three factors, peroxisome proliferator-activated receptor y （PPARγ）, CCAAT/element-binding protein a （C/EBPa） and sterol regulatory element binding protein-1 （SREBP1）, play fundamental roles in metabolic pathways. And they are also important in adipocyte differentiation. Expressions of these factors are regulated by some compounds such as fatty acids or some steroid hormones （insulin） which is stimulated by the nutritional level. Furthermore, these factors are related to some metabolic diseases including type II diabetes and obesity, Lots of researches have focused on relationships between the factors and the genetic diseases. Different functions of factors on inducing the adipocyte differentiation are other hot spots according to previous studies. This paper summarized these studies and gave a limpid description of structures and functions of these genes.

Adipogenesis licensing and execution are disparately linked to cell proliferation

Coordination of cell differentiation and proliferation is a key issue in the development process of multi-cellular organisms and stem cells. Here we provide evidence that the establishment of adipocyte differentiation of 3T3-L1 cells requires two processes： the licensing of an adipogenesis gene-expression program within a particular growth-arrest stage, i.e., the contact-inhibition stage, and then the execution of this program in a cell-cycle-independent manner, by which the licensed progenitors are differentiated into adipocytes in the presence of inducing factors. Our results showed that differentiation licensing of 3T3-L1 cells during the contact-inhibition stage involved epigenetic modifications such as DNA methylation and histone modifications, whereas disturbing these epigenetic modifications by DNA methylation inhibitors or RNAi during the contact-inhibition stage significantly reduced adipogenesis efficiency. More importantly, when these licensed 3T3-L1 cells were re-cultured under non-differentiating conditions or treated only with insulin, this adipogenesis commitment could be maintained from one cell generation to the next, whereby the licensed program could be activated in a cell-cycle-independent manner once these cells were subjected to adipo- genesis-inducing conditions. This result suggests that differentiation licensing and differentiation execution can be uncoupled and disparately linked to cell proliferation. Our findings deliver a new concept that cell-fate decision can be subdivided into at least two stages, licensing and execution, which might have different regulatory relationships with cell proliferation. In addition, this new concept may provide a clue for developing new strategies against obesity.

Effect of rhBMP-2 sustained-release nanocapsules on the ectopic osteogenesis process in Sprague-Dawley rats

Objective:To explore the effect of sustained-release recombinant human bone morphogenetic protein-2(rhBMP-2) on ectopic osteogenesis in the muscle pouches of rats through preparing rhBMP-2 sustained-release capsules by wrapping morphogenesis protein bones-2(BMP-2)using chitosan nanoparticles,and compositing collagen materials.Methods:Twenty four SpragueDawley rats were randomly divided into four groups with six rats in each group,that is Group A(control group),Group B(only treated with collagen),Group C(rhBMP-2+collagen treated group) and Group D(rhBMP-2/cs+collagen treated group).The composite materials for each group were implanted in the bilateral peroneal muscle pouches in rats.The peroneal muscles were only separated without implanting any materials in control group.Rats were sacrificed 2 weeks and 4 weeks post treatment and samples were cut off for general observation,Micro CT scans and histological observation.Results:General observation showed no new bone formation in Groups A and B mice,while new bones were formed in Groups C and D mice.Two weeks after treatment Micro CT scans showed that The bone volume fraction(BVF),trabecular thickness(Tb. Th),bone mineral density(BMD) in Group C mice were all higher than that in Group D(P<0.05). At the fourth week,the BVK,Tb.Th and BMD were significantly higher than that at the second week(P<0.01).Conclusions:The slow-release effect of rhBMP-2/cs sustained-release capsules can significantly promote ectopic osteogenesis.Its bone formation effect is better than that of rhBMP-2 burst-release group.

C/EBPα regulates SIRT1 expression during adipogenesis

SIRT1 plays an important role in adipogenesis, but how SIRT1 is regulated in adipogenesis is largely unknown. In this study, we show that both SIRT1 protein and mRNA levels were increased along with CCAAT/enhancer-binding protein a （C/EBPa） during adipocyte differentiation. C/EBPa, but not C/EBPap30, activated SIRT1 promoter in both HeLa cells and 3T3-L1 preadipocytes. Furthermore, C/EBPa upregulated SIRT1 mRNA and protein levels in HeLa cells and increased SIRT1 expression in a p53-independent manner in Soas2 cells. In preadipocytes, ectopic expression of C/EBPa upregulated SIRT1 protein level and knockdown of C/EBPa led to the decrease of SIRTI pro- tein level. Moreover, by promoter deletion analysis, gel shift assay and chromatin immunoprecipitation, we found that C/EBPa bound to the SIRT1 promoter at a consensus C/EBPα binding site. These data demonstrate that C/ EBPα regulates SIRT1 expression during adipogenesis by directly binding to the SIRT1 promoter.