Conventional and multi-omics assessments of subacute inhalation toxicity due to propylene glycol and vegetable glycerin aerosol produced by electronic cigarettes.

Propylene glycol (PG) and vegetable glycerin (VG) are the most common solvents used in electronic cigarette liquids. No long-term inhalation toxicity assessments have been performed combining conventional and multi-omics approaches on the potential respiratory effects of the solvents in vivo. In this study, the systemic toxicity of aerosol generated from a ceramic heating coil-based e-cigarette was evaluated. First, the aerosol properties were characterized, including carbonyl emissions, the particle size distribution, and aerosol temperatures. To determine toxicological effects, rats were exposed, through their nose only, to filtered air or a propylene glycol (PG)/ glycerin (VG) (50:50, %W/W) aerosol mixture at the target concentration of 3 mg/L for six hours daily over a continuous 28-day period. Compared with the air group, female rats in the PG/VG group exhibited significantly lower body weights during both the exposure period and recovery period, and this was linked to a reduced food intake. Male rats in the PG/VG group also experienced a significant decline in body weight during the exposure period. Importantly, rats exposed to the PG/VG aerosol showed only minimal biological effects compared to those with only air exposure, with no signs of toxicity. Moreover, the transcriptomic, proteomic, and metabolomic analyses of the rat lung tissues following aerosol exposure revealed a series of candidate pathways linking aerosol inhalation to altered lung functions, especially the inflammatory response and disease. Dysregulated pathways of arachidonic acids, the neuroactive ligand-receptor interaction, and the hematopoietic cell lineage were revealed through integrated multi-omics analysis. Therefore, our integrated multi-omics approach offers novel systemic insights and early evidence of environmental-related health hazards associated with an e-cigarette aerosol using two carrier solvents in a rat model.

Evaluation of the inhalation toxicity of arecoline benzoate aerosol in rats.

Arecoline is a pharmacologically active alkaloid isolated from Areca catechu. There are no published data available regarding the inhalation toxicity of arecoline in animals. This study aimed to evaluate the inhalation toxicity of arecoline in vitro and in vivo. For this purpose, arecoline benzoate (ABA) salt was prepared to stabilize arecoline in an aerosol. The MTT assay determined the half-maximal inhibitory concentration values of ABA and arecoline in A549 cell proliferation to be 832 and 412 µg/ml, respectively. The toxicity of acute and subacute inhalation in Sprague-Dawley rats was evaluated using the guidelines of the Organization for Economic Cooperation and Development. For acute inhalation, the median lethal concentration value of ABA solvent was >5175 mg/m3 . After the exposure and during the recovery period, no treatment-related clinical signs were observed. In the 28-Day inhalation toxicity test, daily nose-only exposure to 2510 mg/m3 aerosol of the ABA solvent contained 75 mg/m3 ABA for male rats and 375 mg/m3 ABA for female rats, which caused no observed adverse effects, except for the decreased body weight gain in male rats exposed to 375 mg/m3 ABA. In this study, the no observed adverse effect level (NOAEL) for the 28-day repeated dose inhalation of ABA aerosol was calculated to be around 13 mg/kg/day for male rats and 68.8 mg/kg/day for female rats, respectively.

Author Correction: Plumbagin attenuates cancer cell growth and osteoclast formation in the bone microenvironment of mice.

During re-read of our previously article Plumbagin attenuates cancer cell growth and osteoclast formation in the bone microenvironment of micepublished in Acta Pharmacologica Sinica, we were regretted to point out a mistake shown in Fig. 2a. The representative figure chosen to indicate the inhibitory effect of 4 mg/kg of plumbagin treatment at 1 week against MDA-MB-231SArfp cells localization within bone environment was incorrect due to the mishandling in manuscript preparation. Although this correction does not affect the results and conclusion of the paper, all the authors agree on the correction of our negligence as providing the corrected Fig. 2a presented below. We feel sorry and apologize for all the inconvenience it caused.An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Author Correction: Synergistic suppression of human breast cancer cells by combination of plumbagin and zoledronic acid in vitro.

The authors regretted to find the mis-representative images in Fig. 3a, c and Fig. 4a, c when re-read our previously published article Synergistic suppression of human breast cancer cells by combination of plumbagin and zoledronic acid In vitro (DOI: 10.1038/aps.2015.42) in the journal of Acta Pharmacologica Sinica. This mistake occurred due to the careless compilation when the authors tried to show the synergistic effect against tumor apoptosis during figure presentation process. The right Fig. 3a, c and Fig. 4a, c were provided below. Despite that this correction does not affect the results and conclusions of the aforementioned paper, all the authors still consent on the correction of this negligence. We apologize to the Editor and the readership of the journal for any inconvenience caused. Your thoughtful understanding is highly appreciated.

Aberrant expression of miR-451a contributes to 1,2-dichloroethane-induced hepatic glycerol gluconeogenesis disorder by inhibiting glycerol kinase expression in NIH Swiss mice.

The identification of aberrant microRNA (miRNA) expression during chemical-induced hepatic dysfunction will lead to a better understanding of the substantial role of miRNAs in liver diseases. 1,2-Dichloroethane (1,2-DCE), a chlorinated organic toxicant, can lead to hepatic abnormalities in occupationally exposed populations. To explore whether aberrant miRNA expression is involved in liver abnormalities mediated by 1,2-DCE exposure, we examined alterations in miRNA expression patterns in the livers of NIH Swiss mice after dynamic inhalation exposure to 350 or 700 mg m-3 1,2-DCE for 28 days. Using a microarray chip, we discovered that only mmumiR-451a was significantly upregulated in the liver tissue of mice exposed to 700 mg m-3 1,2-DCE; this finding was validated by quantitative real-time polymerase chain reaction. In vitro study revealed that it was metabolite 2-chloroacetic acid, not 1,2-DCE that resulted in the upregulation of mmu-miR-451a in the mouse AML12 cell line. Furthermore, our data showed that the upregulation of mmu-miR-451a induced by 2-chloroacetic acid could suppress the expression of glycerol kinase and lead to the inhibition of glycerol gluconeogenesis in mouse liver tissue and AML12 cells. These observations provide evidence that hepatic mmu-miR-451a responds to 1,2-DCE exposure and might induce glucose metabolism disorders by suppressing the glycerol gluconeogenesis process.

Upregulation of Akt signaling enhances femoral fracture healing by accelerating atrophic quadriceps recovery.

Muscle damage and disuse muscular atrophy are detrimental for fracture healing. It has been reported that the Akt signaling pathway plays a role in skeletal muscle hypertrophy and atrophy. The aim of this study was to further investigate whether promoting local muscle function through regulating Akt signaling affects fracture healing. For this purpose, we combined a rat model of short-term atrophy of the quadriceps with a femoral fracture model. In brief, botulinum toxin-A (BTX) were administered locally into the quadriceps one week before femur osteotomy to induce muscle atrophy. For the following weeks after BTX treatment, animals received injection of the Akt activator SC79 (20mg/kg/week) or the Akt inhibitor MK2206 (100mg/kg/week). We found that SC79 significantly accelerated the recovery of quadriceps weight and fiber size after BTX treatment. Moreover, animals that received SC79 injection showed greater bone callus volumes and superior femur mechanical properties. Immunological analysis revealed that the expression levels of the muscle-specific marker myosin heavy chain (MHC) were increased while expression of a negative regulator of muscle mass and function, myostatin, was decreased after SC79 treatment. Furthermore, SC79 increased the mRNA levels of the myogenic regulatory factors MyoD, MRF4 and Myf5 and promoted myotube formation in vitro. Taken together, these findings reveal that SC79 could accelerate the recovery of reversible muscular atrophy induced by BTX and subsequently promote fracture healing through activation of the Akt signaling pathway, which suggests its therapeutic potential in orthopedics.

Epigenetic landscape in PPARγ2 in the enhancement of adipogenesis of mouse osteoporotic bone marrow stromal cell.

Osteoporosis is one of the most prevalent skeletal system diseases; yet, its pathophysiological mechanisms remain elusive. Adipocytes accumulate remarkably in the bone marrow of osteoporotic patients. The potential processes and molecular mechanisms underlying adipogenesis in osteoporotic BMSCs have attracted significant attention as adipocytes and osteoblasts share common precursor cells. Some environmental factors influence bone mass through epigenetic mechanisms; however, the role of epigenetic modifications in osteoporosis is just beginning to be investigated, and there is still little data regarding their involvement. In the current study, we investigated how epigenetic modifications, including DNA methylation and histone modifications, lead to adipogenesis in the bone marrow during osteoporosis. A glucocorticoid-induced osteoporosis (GIO) mouse model was established, and BMSCs were isolated from the bone marrow. Compared with normal BMSCs, osteoporotic BMSCs had significantly increased adipogenesis potential and decreased osteogenesis potential. In osteoporotic BMSCs, PPARγ2 regulatory region DNA hypo-methylation, histone 3 and 4 hyper-acetylation and H3K9 hypo-di-methylation were observed. These epigenetic modifications were involved not only in PPARγ2 expression but also in osteoporotic BMSC adipogenic differentiation potential. We also found that Wnt/ß-catenin signal played an important role in the establishment and maintenance of epigenetic modifications at PPARγ2 promoter in osteoporotic BMSCs. Finally, we inhibited adipogenesis and rescued osteogenesis of osteoporotic BMSCs by modulating those epigenetic modifications. Our study provides a deeper insight into the pathophysiology of osteoporosis and identifies PPARγ2 as a new target for osteoporosis therapy based on epigenetic mechanisms.

Geraniin suppresses RANKL-induced osteoclastogenesis in vitro and ameliorates wear particle-induced osteolysis in mouse model.

Wear particle-induced osteolysis and subsequent aseptic loosening remains the most common complication that limits the longevity of prostheses. Wear particle-induced osteoclastogenesis is known to be responsible for extensive bone erosion that leads to prosthesis failure. Thus, inhibition of osteoclastic bone resorption may serve as a therapeutic strategy for the treatment of wear particle induced osteolysis. In this study, we demonstrated for the first time that geraniin, an active natural compound derived from Geranium thunbergii, ameliorated particle-induced osteolysis in a Ti particle-induced mouse calvaria model in vivo. We also investigated the mechanism by which geraniin exerts inhibitory effects on osteoclasts. Geraniin inhibited RANKL-induced osteoclastogenesis in a dose-dependent manner, evidenced by reduced osteoclast formation and suppressed osteoclast specific gene expression. Specially, geraniin inhibited actin ring formation and bone resorption in vitro. Further molecular investigation demonstrated geraniin impaired osteoclast differentiation via the inhibition of the RANKL-induced NF-κB and ERK signaling pathways, as well as suppressed the expression of key osteoclast transcriptional factors NFATc1 and c-Fos. Collectively, our data suggested that geraniin exerts inhibitory effects on osteoclast differentiation in vitro and suppresses Ti particle-induced osteolysis in vivo. Geraniin is therefore a potential natural compound for the treatment of wear particle induced osteolysis in prostheses failure.

Osteosarcoma cells promote the production of pro-tumor cytokines in mesenchymal stem cells by inhibiting their osteogenic differentiation through the TGF-ß/Smad2/3 pathway.

Mesenchymal stem cells (MSCs) are among the most important components of the osteosarcoma microenvironment and are reported to promote tumor progression. However, the means by which osteosarcoma cells modulate MSC behavior remains unclear. The aim of this study was to determine the effects of osteosarcoma cells on both the production of pro-tumor cytokines by mesenchymal stem cells (MSCs) and the osteogenic differentiation of MSCs. High level of transforming growth factor-ß (TGF-ß) was detected in three osteosarcoma cell lines. Conditioned media (CM) from the osteosarcoma cell lines Saos-2 and U2-OS were used to stimulate the cultured MSCs. We found that osteosarcoma cells promoted the production of IL-6 and VEGF in MSCs by inhibiting their osteogenic differentiation. Furthermore, TGF-ß in tumor CM was proved to be an important factor. The TGF-ß neutralizing antibody antagonized the effects induced by osteosarcoma CM. The inhibition of Smad2/3 by siRNA significantly decreased the production of IL-6 and VEGF in MSCs and induced their osteogenic differentiation. We also found that Smad2/3 enhanced the expression of ß-catenin in MSCs by decreasing the level of Dickkopf-1 (DKK1). Although the inhibition of ß-catenin did not affect the production of IL-6 or VEGF, or the gene expression of the early osteogenic markers Runx2 and ALP, it did enhance the gene expression of osteocalcin. Taken together, our data indicate that osteosarcoma cells secrete TGF-ß to maintain the stemness of MSCs and promote the production of pro-tumor cytokines by these cells.

Synergistic suppression of human breast cancer cells by combination of plumbagin and zoledronic acid In vitro.

AIM: Zoledronic acid (ZA), a bisphosphonate, is currently used in combination with chemotherapeutic agents to suppress breast cancer cell proliferation or breast cancer-induced osteolysis. The aim of this study was to investigate the effects of ZA combined with a natural anticancer compound plumbagin (PL) against human breast cancer cells in vitro. METHODS: Human breast cancer MDA-MB-231SArfp cells were treated with ZA, PL or a combination of ZA and PL. The cell growth, apoptosis and migration were evaluated using CCK-8 assay, flow cytometry and transwell assay, respectively. The expression of apoptosis-related proteins was measured using real-time PCR and Western blotting. Synergism was evaluated using Compusyn software, and the combination index (CI) and drug reduction index (DRI) values were determined. RESULTS: PL or ZA alone caused mild cytotoxicity (the IC50 value at 24 h was 12.18 and above 100 µmol/L, respectively). However, the combination of ZA and PL caused a synergistic cytotoxicity (CI=0.26). The DRI values also showed a synergistic effect between PL and ZA, with actual values of 5.52 and 3.59, respectively. Furthermore, PL and ZA synergistically induced apoptosis and inhibited migration of the breast cancer cells. Moreover, the combination of ZA and PL decreased the expression of Notch-1, cleaved PARP, Bcl-2 and Bcl-xl, and increased the expression of cleaved caspase-3, CDKN1A and ID1. When the breast cancer cells were transfected with specific siRNA against Notch-1, the combination of ZA and PL markedly increased the expression of Bcl-2. CONCLUSION: Combination of ZA and PL synergistically suppresses human breast cancer MDA-MB-231SArfp cells in vitro. PL can inhibit ZA-induced activation of the Notch-1 signaling pathway and subsequently reduce the expression of Bcl-2, thus potentiating cancer cell apoptosis.

Dioscin inhibits osteoclast differentiation and bone resorption though down-regulating the Akt signaling cascades.

Bone resorption is the unique function of osteoclasts (OCs) and is critical for both bone homeostasis and pathologic bone diseases including osteoporosis, rheumatoid arthritis and tumor bone metastasis. Thus, searching for natural compounds that may suppress osteoclast formation and/or function is promising for the treatment of osteoclast-related diseases. In this study, we for the first time demonstrated that dioscin suppressed RANKL-mediated osteoclast differentiation and bone resorption in vitro in a dose-dependent manner. The suppressive effect of dioscin is supported by the reduced expression of osteoclast-specific markers. Further molecular analysis revealed that dioscin abrogated AKT phosphorylation, which subsequently impaired RANKL-induced nuclear factor-kappaB (NF-κB) signaling pathway and inhibited NFATc1 transcriptional activity. Moreover, in vivo studies further verified the bone protection activity of dioscin in osteolytic animal model. Together our data demonstrate that dioscin suppressed RANKL-induced osteoclast formation and function through Akt signaling cascades. Therefore, dioscin is a potential natural agent for the treatment of osteoclast-related diseases.

Plumbagin attenuates cancer cell growth and osteoclast formation in the bone microenvironment of mice.

AIM: To investigate the effects of plumbagin, a naphthoquinone derived from the medicinal plant Plumbago zeylanica, on human breast cancer cell growth and the cancer cell-induced osteolysis in the bone microenvironment of mice. METHODS: Human breast cancer cell subline MDA-MB-231SA with the ability to spread and grow in the bone was tested. The cell proliferation was determined using the CCK-8 assay. Apoptosis was detected with Annexin V/PI double-labeled flow cytometry. Red fluorescent protein-labeled MDA-MB-231SArfp cells were injected into the right tibia of female BALB/c-nu/nu mice. Three days after the inoculation, the mice were injected with plumbagin (2, 4, or 6 mg/kg, ip) 5 times per week for 7 weeks. The growth of the tumor cells was monitored using an in vivo imaging system. After the mice were sacrificed, the hind limbs were removed for radiographic and histological analyses. RESULTS: Plumbagin (2.5-20 µmol/L) concentration-dependently inhibited the cell viability and induced apoptosis of MDA-MB-231SA cells in vitro (the IC50 value of inhibition of cell viability was 14.7 µmol/L). Administration of plumbagin to breast cancer bearing mice delayed the tumor growth by 2-3 weeks and reduced the tumor volume by 44%-74%. The in vivo imaging study showed that plumbagin dose-dependently inhibited MDA-MB-231SArfp cell growth in bone microenvironment. Furthermore, X-ray images and micro-CT study demonstrated that plumbagin reduced bone erosion area and prevented a decrease in bone tissue volume. Histological studies showed that plumbagin dose-dependently inhibited the breast cancer cell growth, enhanced the cell apoptosis and reduced the number of TRAcP-positive osteoclasts. CONCLUSION: Plumbagin inhibits the cell growth and induces apoptosis in human breast cancer cells in mice bone microenvironment, leading to significant reduction in osteolytic lesions caused by the tumor cells.

The CREB-Smad6-Runx2 axis contributes to the impaired osteogenesis potential of bone marrow stromal cells in fibrous dysplasia of bone.

Fibrous dysplasia (FD) is characterized by the replacement of normal bone with abnormal fibro-osseous tissue. This disorder is due to activating missense mutations in the GNAS gene and resultant over-production of cAMP. However, the signalling pathways that contribute to FD pathogenesis remain unknown. In the current study, bone marrow stromal cells (BMSCs) carrying GNAS R201H mutation were isolated from lesion site of FD patients. cAMP accumulation, enhanced proliferation and impaired osteogenesis potential were observed. Two cell models, BMSCs treated with excess exogenous cAMP and BMSCs infected with lentivirus GNAS R201H, were established to model the pathological conditions of FD and used to investigate its pathogenesis. The results suggest that the CREB-Smad6-Runx2 axis is involved in osteogenesis dysfunction of BMSCs with the FD phenotype. We confirmed the results in FD lesion-derived BMSCs and observed that the impaired osteogenesis potential of BMSCs infected with lentivirus GNAS (R201H) was recovered in vitro through modulation of the CREB-Smad6-Runx2 axis. This study provides useful insight into the signalling pathways involved in the FD phenotype and facilitates dissection of the molecular pathogenesis of FD and testing of novel therapies.

Effects of crystal structure and electronic properties on lithium storage performance of artificial graphite.

Graphite is nowadays commonly used as the main component of anode materials of lithium-ion batteries (LIBs). It is essential to deeply investigate the fundamentals of artificial graphite to obtain excellent anode, especially crystal structure and electronic properties. In this report, a series of graphite with different crystal structure were synthesized and used for anodes of LIBs. Meanwhile, a concise method is designed to evaluate qualitatively the conductivity of lithium ion (σLi) and a profound mechanism of lithium storage was revealed in terms of solid state theory. The conductivity analysis demonstrates that the graphite with longer crystal plane and lower stacking layers possesses higher conductivity of electron (σe). On the other hand, lower initial charge/discharge voltage indicates the graphite with lower La and higher Lc holds higher conductivity of lithium ion (σLi). According to the solid state theory, graphite is considered to be a semi-conductor with zero activation energy, while the lithium intercalated graphite is like a conductor. The conductivity of graphite mainly depends on the σe, while the conductivity of lithium intercalated graphite can be determined by the summation of σe and σLi. In lower charge/discharge rate, Li+ have enough time to insert into the graphitic layer, making the special capacity of graphite primarily determined by σe. However, with the increase of charge/discharge rate, Li+ insertion/extraction will become more difficult, making σLi become the mainly factor of the graphite special capacity. Therefore, the graphite with longer crystal plane and lower stacking layers owns higher specific capacity under slow charge/discharge rate, the graphite with shorter crystal plane and higher stacking layers shows relatively lower specific capacity under rapid charge/discharge rate. These results provide important insights into the design and improvement of graphite's electrochemical performance.

CCL3 in the bone marrow microenvironment causes bone loss and bone marrow adiposity in aged mice.

The central physiological role of the bone marrow renders bone marrow stromal cells (BMSCs) particularly sensitive to aging. With bone aging, BMSCs acquire a differentiation potential bias in favor of adipogenesis over osteogenesis, and the underlying molecular mechanisms remain unclear. Herein, we investigated the factors underlying age-related changes in the bone marrow and their roles in BMSCs' differentiation. Antibody array revealed that CC chemokine ligand 3 (CCL3) accumulation occurred in the serum of naturally aged mice along with bone aging phenotypes, including bone loss, bone marrow adiposity, and imbalanced BMSC differentiation. In vivo Ccl3 deletion could rescue these phenotypes in aged mice. CCL3 improved the adipogenic differentiation potential of BMSCs, with a positive feedback loop between CCL3 and C/EBPα. CCL3 activated C/EBPα expression via STAT3, while C/EBPα activated CCL3 expression through direct promoter binding, facilitated by DNA hypomethylation. Moreover, CCL3 inhibited BMSCs' osteogenic differentiation potential by blocking ß-catenin activity mediated by ERK-activated Dickkopf-related protein 1 upregulation. Blocking CCL3 in vivo via neutralizing antibodies ameliorated trabecular bone loss and bone marrow adiposity in aged mice. This study provides insights regarding age-related bone loss and bone marrow adiposity pathogenesis and lays a foundation for the identification of new targets for senile osteoporosis treatment.

Constitutively activated AMPKα1 protects against skeletal aging in mice by promoting bone-derived IGF-1 secretion.

Senile osteoporosis is characterized by age-related bone loss and bone microarchitecture deterioration. However, little is known to date about the mechanism that maintains bone homeostasis during aging. In this study, we identify adenosine monophosphate-activated protein kinase alpha 1 (AMPKα1) as a critical factor regulating the senescence and lineage commitment of mesenchymal stem cells (MSCs). A phospho-mutant mouse model shows that constitutive AMPKα1 activation prevents age-related bone loss and promoted MSC osteogenic commitment with increased bone-derived insulin-like growth factor 1 (IGF-1) secretion. Mechanistically, upregulation of IGF-1 signalling by AMPKα1 depends on cAMP-response element binding protein (CREB)-mediated transcriptional regulation. Furthermore, the essential role of the AMPKα1/IGF-1/CREB axis in promoting aged MSC osteogenic potential is confirmed using three-dimensional (3D) culture systems. Taken together, these results can provide mechanistic insight into the protective effect of AMPKα1 against skeletal aging by promoting bone-derived IGF-1 secretion.

MAPKAPK5-AS1 drives the progression of hepatocellular carcinoma via regulating miR-429/ZEB1 axis.

BACKGROUND: Hepatocellular carcinoma (HCC) is a common malignancy. Long non-coding RNAs (lncRNAs) partake in the progression of HCC. However, the role of lncRNA MAPKAPK5-AS1 in the development of HCC has not been fully clarified. METHODS: RNA sequencing data and quantitative real-time polymerase chain reaction (qRT-PCR) were adopted to analyze MAPKAPK5-AS1, miR-429 and ZEB1 mRNA expressions in HCC tissues and cell lines. Western blot was used to detect ZEB1, E-cadherin and N-cadherin protein expressions. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Transwell and flow cytometry assays were adopted to analyze the effects of MAPKAPK5-AS1 on cell proliferation, migration, invasion and apoptosis. Besides, luciferase reporter assay was used to detect the targeting relationship between miR-429 and MAPKAPK5-AS1 or ZEB1 3'UTR. The xenograft tumor mouse models were used to explore the effect of MAPKAPK5-AS1 on lung metastasis of HCC cells. RESULTS: MAPKAPK5-AS1 and ZEB1 expressions were up-regulated in HCC tissues, and miR-429 expression is down-regulated in HCC tissues. MAPKAPK5-AS1 knockdown could significantly impede HCC cell proliferation, migration, invasion and epithelial-mesenchymal transition (EMT), as well as promote cell apoptosis. MAPKAPK5-AS1 overexpression could enhance L02 cell proliferation, migration, invasion and EMT, and inhibit cell apoptosis. MiR-429 was validated to be the target of MAPKAPK5-AS1, and miR-429 inhibitors could partially offset the effects of knocking down MAPKAPK5-AS1 on HCC cells. MAPKAPK5-AS1 could positively regulate ZEB1 expression through repressing miR-429. Moreover, fewer lung metastatic nodules were observed in the lung tissues of nude mice when the MAPKAPK5-AS1 was knocked down in HCC cells. CONCLUSION: MAPKAPK5-AS1 can adsorb miR-429 to promote ZEB1 expression to participate in the development of HCC.

Human mesenchymal stem cells promote growth of osteosarcoma: involvement of interleukin-6 in the interaction between human mesenchymal stem cells and Saos-2.

Our previous study showed that exogenous human mesenchymal stem cells (hMSCs) targeted established osteosarcoma and promoted its growth and pulmonary metastasis in vivo. As a follow-up, the present study aimed to investigate how hMSCs would interact with Saos-2 through autocrine/paracrine communication. The results showed that co-injection of hMSCs with Saos-2 into the proximal tibia of nude mice could promote tumor growth and progression. In vitro, the proliferation of Saos-2 and hMSCs was promoted by each other's conditioned medium, in which interleukin-6 (IL-6) played an important role. Osteogenic differentiation of hMSCs could be inhibited by conditioned medium of Saos-2, in which IL-6 was also involved. Furthermore, decreased IL-6 secretion by hMSCs during its osteogenesis and increased IL-6 secretion in response to conditioned medium of Saos-2 were observed. Based on these data, we suggest that there was a positive feedback loop of IL-6 in the interaction between hMSCs and Saos-2.

The role of CCAAT/enhancer binding protein (C/EBP)-alpha in osteogenesis of C3H10T1/2 cells induced by BMP-2.

The balance between osteogenesis and adipogenesis of mesenchymal stem cells is disrupted in various human diseases. Investigating the mechanisms that fine-tune this balance is of medical importance. Identification of potential target gene which can be used to study the relationship between them could be really helpful for this purpose. In the current study, we used C3H10T1/2 as model cells and through which two models of both osteogenesis induced by bone-morphogenetic protein (BMP)-2 and transdifferentiation from osteogenesis to adipogenesis were established. We investigated the role of CCAAT/enhancer binding protein (C/EBP)-alpha in these two systems. Then from epigenetic point of view, we elucidated the underlying molecular mechanisms preliminarily. The results showed that down-regulations of both C/EBP-alpha expression and its inducibility in response to insulin, fetal bovine serum, methylisobutylxanthine and dexamethasone (IFMD) adipogenic hormonal cocktail were observed in terminal stage of osteogenesis of C3H10T1/2 cells induced by BMP-2. And overexpression of C/EBP-alpha could lead to inhibition of osteogenesis differentiation and rescue attenuation of potential of adipogenic conversion in this process. Furthermore, we provided evidence that remarkable DNA hypermethylation and histones 3 and 4 hypoacetylation in -1286 bp/1065 bp promoter region of C/EBP-alpha were involved in both of down-regulations. Our data suggest that C/EBP-alpha functions as regulator in the balance between osteogenesis and adipogenesis of C3H10T1/2 cells and may be a therapeutic target.

Improved antibacterial properties of collagen I/hyaluronic acid/quaternized chitosan multilayer modified titanium coatings with both contact-killing and release-killing functions.

Implant infection is one of the most severe complications after orthopedic surgery. The construction of an antibacterial coating on orthopedic implants with release-killing or contact-killing is one of the most efficient strategies to prevent implant-related infections. Here we reported a hydroxypropyltrimethyl ammonium chloride chitosan (HACC) based multilayer modified plasma-sprayed porous titanium coating generated via the layer-by-layer covalent-immobilized method. We demonstrated that the multilayer coating inhibited the colonization and biofilm formation of several bacterial strains, including Staphylococcus aureus (ATCC 25923), methicillin-resistant Staphylococcus aureus (MSRA, ATCC 43300) and clinical isolates of methicillin-resistant Staphylococcus epidermidis (MRSE 287), in vitro. HACC in the multilayer was released slowly with the degradation of the coating under the action of collagenase, further killing the planktonic bacteria, while the remaining HACC could kill the colonized bacteria. In a rat model of femur implants, the HACC-based multilayer-modified TCs effectively controlled the infection caused by MRSA and prevented bone destruction. Therefore, the HACC-based multilayer modified TCs with multiple antimicrobial properties could be a new potential ideal surface modification strategy to prevent implant associated infections.