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1.
Biomed Mater ; 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31665702

RESUMO

Because the collagen membrane lacks osteoinductivity, it must be modified with bioactive components to trigger rapid bone regeneration. In this study, we aimed to evaluate the bone regeneration effects of a collagen membrane chemically conjugated with stromal cell-derived factor-1 alpha (SDF­1α) in rat models. To this end, different collagen membranes from four groups including a control group with a Bio-Oss bone substitute + collagen membrane; physical adsorption group with Bio-Oss + SDF-1α physically adsorbed on the collagen membrane; chemical cross-linking group with Bio-Oss + SDF-1α chemically cross-linked to the collagen membrane; and cell-seeding group with Bio-Oss + bone marrow mesenchymal stem cells (BMSCs) seeded onto the collagen membrane were placed in critical-sized defect models using a guided bone regeneration technique. At 4 and 8 weeks, the specimens were analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, micro-computed tomography, and histomorphology analyses. Furthermore, ectopic osteogenesis was examined by histological analysis with Von Kossa staining, with the samples counterstained by hematoxylin and eosin and immunohistochemical staining. The results showed that in the chemical cross-linking group and cell-seeding group, the bone volume fraction, bone surface area fraction, and trabecular number were significantly increased and showed more new bone formation compared to the control and physical adsorption groups. Von Kossa-stained samples counterstained with hematoxylin and eosin and subjected to immunohistochemical staining of 4-week implanted membranes revealed that the chemical cross-linking group had the largest number of microvessels. The collagen membrane chemically conjugated with SDF-1α to significantly promote new bone and microvessel formation compared to SDF-1α physical adsorption and showed similar effects on new bone formation as a BMSC seeding method. This study provided a cell-free approach for shortening the bone healing time and improving the success rate of guided bone regeneration.

2.
J Am Heart Assoc ; 8(11): e011625, 2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31433721

RESUMO

Background Branched-chain amino acid (BCAA) catabolic defect is an emerging metabolic hallmark in failing hearts in human and animal models. The therapeutic impact of targeting BCAA catabolic flux under pathological conditions remains understudied. Methods and Results BT2 (3,6-dichlorobenzo[b]thiophene-2-carboxylic acid), a small-molecule inhibitor of branched-chain ketoacid dehydrogenase kinase, was used to enhance BCAA catabolism. After 2 weeks of transaortic constriction, mice with significant cardiac dysfunctions were treated with vehicle or BT2. Serial echocardiograms showed continuing pathological deterioration in left ventricle of the vehicle-treated mice, whereas the BT2-treated mice showed significantly preserved cardiac function and structure. Moreover, BT2 treatment improved systolic contractility and diastolic mechanics. These therapeutic benefits appeared to be independent of impacts on left ventricle hypertrophy but associated with increased gene expression involved in fatty acid utilization. The BT2 administration showed no signs of apparent toxicity. Conclusions Our data provide the first proof-of-concept evidence for the therapeutic efficacy of restoring BCAA catabolic flux in hearts with preexisting dysfunctions. The BCAA catabolic pathway represents a novel and potentially efficacious target for treatment of heart failure.

3.
Diabetes ; 68(9): 1730-1746, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31167878

RESUMO

Recent studies implicate a strong association between elevated plasma branched-chain amino acids (BCAAs) and insulin resistance (IR). However, a causal relationship and whether interrupted BCAA homeostasis can serve as a therapeutic target for diabetes remain to be established experimentally. In this study, unbiased integrative pathway analyses identified a unique genetic link between obesity-associated IR and BCAA catabolic gene expression at the pathway level in human and mouse populations. In genetically obese (ob/ob) mice, rate-limiting branched-chain α-keto acid (BCKA) dehydrogenase deficiency (i.e., BCAA and BCKA accumulation), a metabolic feature, accompanied the systemic suppression of BCAA catabolic genes. Restoring BCAA catabolic flux with a pharmacological inhibitor of BCKA dehydrogenase kinase (BCKDK) ( a suppressor of BCKA dehydrogenase) reduced the abundance of BCAA and BCKA and markedly attenuated IR in ob/ob mice. Similar outcomes were achieved by reducing protein (and thus BCAA) intake, whereas increasing BCAA intake did the opposite; this corroborates the pathogenic roles of BCAAs and BCKAs in IR in ob/ob mice. Like BCAAs, BCKAs also suppressed insulin signaling via activation of mammalian target of rapamycin complex 1. Finally, the small-molecule BCKDK inhibitor significantly attenuated IR in high-fat diet-induced obese mice. Collectively, these data demonstrate a pivotal causal role of a BCAA catabolic defect and elevated abundance of BCAAs and BCKAs in obesity-associated IR and provide proof-of-concept evidence for the therapeutic validity of manipulating BCAA metabolism for treating diabetes.

4.
Nat Biotechnol ; 37(2): 179-185, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30718868

RESUMO

Reference genomes are essential for metagenomic analyses and functional characterization of the human gut microbiota. We present the Culturable Genome Reference (CGR), a collection of 1,520 nonredundant, high-quality draft genomes generated from >6,000 bacteria cultivated from fecal samples of healthy humans. Of the 1,520 genomes, which were chosen to cover all major bacterial phyla and genera in the human gut, 264 are not represented in existing reference genome catalogs. We show that this increase in the number of reference bacterial genomes improves the rate of mapping metagenomic sequencing reads from 50% to >70%, enabling higher-resolution descriptions of the human gut microbiome. We use the CGR genomes to annotate functions of 338 bacterial species, showing the utility of this resource for functional studies. We also carry out a pan-genome analysis of 38 important human gut species, which reveals the diversity and specificity of functional enrichment between their core and dispensable genomes.


Assuntos
Biologia Computacional/métodos , Microbioma Gastrointestinal , Metagenoma , Bactérias/classificação , Análise por Conglomerados , Sequência Conservada , Fezes , Genoma Bacteriano , Genômica , Humanos , Metagenômica , Filogenia , Polimorfismo de Nucleotídeo Único , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
5.
Bioresour Technol ; 277: 46-54, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30658335

RESUMO

This work studied thermal characteristics and product formation mechanism during pyrolysis of penicillin fermentation residue (PR). Results showed that PR pyrolysis proceeded in four stages. The kinetic triplet of each stage was calculated using Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, and integral master-plot methods. The kinetic model for stage 1 was the three-dimensional diffusion model, the simple reaction order model for stage 2 and stage 4, and the nucleation-growth model for stage 3. FTIR analysis suggested that the intensities of absorption peaks of NH, CO, CH, CN, and CO in chars weakened gradually with increasing temperature, corresponding to the production of CH4, CO, NH3, and HCN. GC-MS results indicated that the high protein content in PR resulted in a high fraction of nitrogenated compounds (amides and amines, nitriles, and N-heterocyclic species) in bio-oil. The formation mechanism of these compounds was discussed. Besides, bio-oil also contained large quantities of oxygenated compounds and a few hydrocarbons.


Assuntos
Penicilinas/metabolismo , Fermentação , Cinética , Pirólise , Temperatura Ambiente
6.
J Clin Invest ; 128(12): 5448-5464, 2018 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-30325740

RESUMO

The pathogenesis of ischemic diseases remains unclear. Here we demonstrate the induction of microRNA-668 (miR-668) in ischemic acute kidney injury (AKI) in human patients, mice, and renal tubular cells. The induction was HIF-1 dependent, as HIF-1 deficiency in cells and kidney proximal tubules attenuated miR-668 expression. We further identified a functional HIF-1 binding site in the miR-668 gene promoter. Anti-miR-668 increased apoptosis in renal tubular cells and enhanced ischemic AKI in mice, whereas miR-668 mimic was protective. Mechanistically, anti-miR-668 induced mitochondrial fragmentation, whereas miR-668 blocked mitochondrial fragmentation during hypoxia. We analyzed miR-668 target genes through immunoprecipitation of microRNA-induced silencing complexes followed by RNA deep sequencing and identified 124 protein-coding genes as likely targets of miR-668. Among these genes, only mitochondrial protein 18 kDa (MTP18) has been implicated in mitochondrial dynamics. In renal cells and mouse kidneys, miR-668 mimic suppressed MTP18, whereas anti-miR-668 increased MTP18 expression. Luciferase microRNA target reporter assay further verified MTP18 as a direct target of miR-668. In renal tubular cells, knockdown of MTP18 suppressed mitochondrial fragmentation and apoptosis. Together, the results suggest that miR-668 is induced via HIF-1 in ischemic AKI and that, upon induction, miR-668 represses MTP18 to preserve mitochondrial dynamics for renal tubular cell survival and kidney protection.

7.
Cell Physiol Biochem ; 49(4): 1329-1341, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30205384

RESUMO

BACKGROUND/AIMS: Emerging evidence suggests that the propagation of oral squamous cell carcinoma (OSCC) is influenced by the abnormal expression of microRNAs (miRNAs). This study aimed to characterize the involvement of miR-182-5p in OSCC by targeting the calcium/ calmodulin-dependent protein kinase II inhibitor CAMK2N1. METHODS: miR-182-5p expression was quantified in OSCC tissues and cell lines with reverse transcription polymerase chain reaction (RT-PCR). Cell colony formation, Cell Counting Kit-8 (CCK-8), Ki-67, and nude mouse xenograft assays were used to characterize the role of miR-182-5p in the proliferation of OSCC. A miR-182-5p target gene was identified with western blotting, RT-PCR, and luciferase activity assays. OSCC patient survival based on CAMK2N1 expression was also analyzed. RESULTS: miR-182-5p was up-regulated in in vitro cell lines and in vivo clinical OSCC samples. CCK-8, colony formation, and Ki-67 assays revealed that miR-182-5p promoted the growth and proliferation of OSCC cells. miR-182-5p directly targeted CAMK2N1, as evidenced by luciferase assays and target prediction algorithms. CAMK2N1 operated as a tumor suppressor gene in patients with OSCC. Down-regulating miR-182-5p expression in the CAL-27 cell line restored CAMK2N1-mediated OSCC cell proliferation. miR-182-5p expression inhibited the activation of AKT, ERK1/2, and NF-κB. Mice injected with CAL-27 cells transfected with miR-182-5p-inhibitor demonstrated a significant increase in tumor size and weight and increased CAMK2N1 mRNA and protein expression compared with the miR-negative control group. CONCLUSION: The miR-182-5p-CAMK2N1 pathway can be potentially targeted to regulate the proliferation of OSCC cells.


Assuntos
Carcinoma de Células Escamosas/patologia , MicroRNAs/metabolismo , Neoplasias Bucais/patologia , Proteínas/metabolismo , Animais , Antagomirs/metabolismo , Antagomirs/uso terapêutico , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Estimativa de Kaplan-Meier , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Neoplasias Bucais/tratamento farmacológico , Neoplasias Bucais/metabolismo , NF-kappa B/metabolismo , Proteínas/antagonistas & inibidores , Proteínas/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo
8.
Cell Rep ; 23(5): 1461-1475, 2018 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29719258

RESUMO

In addition to acting as building blocks for biosynthesis, amino acids might serve as signaling regulators in various physiological and pathological processes. However, it remains unknown whether amino acid levels affect the activities of hematopoietic stem cells (HSCs). By using a genetically encoded fluorescent sensor of the intracellular levels of branched-chain amino acids (BCAAs), we could monitor the dynamics of BCAA metabolism in HSCs. A mitochondrial-targeted 2C-type Ser/Thr protein phosphatase (PPM1K) promotes the catabolism of BCAAs to maintain MEIS1 and p21 levels by decreasing the ubiquitination-mediated degradation controlled by the E3 ubiquitin ligase CDC20. PPM1K deficiency led to a notable decrease in MEIS1/p21 signaling to reduce the glycolysis and quiescence of HSCs, followed by a severe impairment in repopulation activities. Moreover, the deletion of Ppm1k dramatically extended survival in a murine leukemia model. These findings will enhance the current understanding of nutrient signaling in metabolism and function of stem cells.

9.
Front Physiol ; 8: 853, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29118722

RESUMO

Recent studies have linked branched-chain amino acid (BCAA) with numerous metabolic diseases. However, the molecular basis of BCAA's roles in metabolic regulation remains to be established. KLF15 (Krüppel-like factor 15) is a transcription factor and master regulator of glycemic, lipid, and amino acids metabolism. In the present study, we found high concentrations of BCAA suppressed KLF15 expression while BCAA starvation induced KLF15 expression, suggesting KLF15 expression is negatively controlled by BCAA.Interestingly, BCAA starvation induced PI3K-AKT signaling. KLF15 induction by BCAA starvation was blocked by PI3K and AKT inhibitors, indicating the activation of PI3K-AKT signaling pathway mediated the KLF15 induction. BCAA regulated KLF15 expression at transcriptional level but not post-transcriptional level. However, BCAA starvation failed to increase the KLF15-promoter-driven luciferase expression, suggesting KLF15 promoter activity was not directly controlled by BCAA. Finally, fasting reduced BCAA abundance in mice and KLF15 expression was dramatically induced in muscle and white adipose tissue, but not in liver. Together, these data demonstrated BCAA negatively regulated KLF15 expression, suggesting a novel molecular mechanism underlying BCAA's multiple functions in metabolic regulation.

10.
Med Sci Monit ; 23: 4885-4894, 2017 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-29023429

RESUMO

BACKGROUND Emerging evidence has shown that downregulation or upregulation of microRNAs (miRNAs) plays an important role in the development and progression of thyroid cancer (TC). However, the potential role of miR-150 and its biological function in TC remains largely unclear. MATERIAL AND METHODS Real-time polymerase chain reaction (RT-qPCR) was employed to detect the expression level of miR-150 and RAB11A in human TC tissue and human normal thyroid tissue. MTT assay, colony formation assay, flow cytometry cell cycle, and apoptosis assay were used to investigate the role of miR-150 and RAB11A on the malignant phenotypes in vitro. Nude mouse xenograft assay and western blot assay was used to verify the function of miR-150 in vivo. Western blot assay and immunofluorescence assay were used to detect the activation of WNT/ß-catenin pathway mediated by miR-150 and RAB11A. EGFP reporter assay, RT-qPCR assay, and western blot assay were used to validate the regulation relationship. RESULTS This study demonstrated that miR-150 expression in human TC tissues was markedly downregulated. Moreover, overexpression of miR-150 markedly inhibited cell proliferation via inducing the cell cycle arrest and promoting cell apoptosis by directly targeting RAB11A in vitro and suppressing tumor growth in vivo. However, overexpression of RAB11A promoted cell malignant phenotypes. In addition, miR-150 restrained the RAB11A mediated WNT/ß-catenin activation in TC cells. CONCLUSIONS miR-150 may function as a suppressor gene in TC cells by inhibiting the RAB11A/WNT/ß-catenin pathway.


Assuntos
MicroRNAs/metabolismo , MicroRNAs/fisiologia , Neoplasias da Glândula Tireoide/genética , Animais , Apoptose/genética , Ciclo Celular/fisiologia , Pontos de Checagem do Ciclo Celular/genética , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células/genética , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Camundongos , Camundongos Nus , MicroRNAs/genética , Reação em Cadeia da Polimerase em Tempo Real , Neoplasias da Glândula Tireoide/metabolismo , Transplante Heterólogo , Via de Sinalização Wnt/genética , Via de Sinalização Wnt/fisiologia , beta Catenina/metabolismo , Proteínas rab de Ligação ao GTP/genética , Proteínas rab de Ligação ao GTP/metabolismo
11.
Int J Med Microbiol ; 307(4-5): 257-267, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28416278

RESUMO

Staphylococcus aureus is an important pathogen that is capable of forming biofilms on biomaterial surfaces to cause biofilm-associated infections. Autoinducer 2 (AI-2), a universal language for interspecies communication, is involved in a variety of physiological activities, although its exact role in Gram-positive bacteria, especially in S. aureus, is not yet thoroughly characterized. Herein we demonstrate that inactivation of luxS, which encodes AI-2 synthase, resulted in increased biofilm formation and higher polysaccharide intercellular adhesion (PIA) production compared with the wild-type strain in S. aureus NCTC8325. The transcript level of rbf, a positive regulator of biofilm formation, was significantly increased in the luxS mutant. All of the parental phenotypes could be restored by genetic complementation and chemically synthesized 4,5-dihydroxy-2,3-pentanedione, the AI-2 precursor molecule, suggesting that AI-2 has a signaling function to regulate rbf transcription and biofilm formation in S. aureus. Phenotypic analysis revealed that the luxS rbf double mutant produced approximately the same amount of biofilms and PIA as the rbf mutant. In addition, real-time quantitative reverse transcription-PCR analysis showed that the icaA transcript level of the rbf mutant was similar to that of the luxS rbf double mutant. These findings demonstrate that the LuxS/AI-2 system regulates PIA-dependent biofilm formation via repression of rbf expression in S. aureus. Furthermore, we demonstrated that Rbf could bind to the sarX and rbf promoters to upregulate their expression.


Assuntos
Proteínas de Bactérias/metabolismo , Biofilmes , Regulação Bacteriana da Expressão Gênica , Homosserina/análogos & derivados , Lactonas/farmacologia , Percepção de Quorum/efeitos dos fármacos , Staphylococcus aureus/genética , Proteínas de Bactérias/genética , Liases de Carbono-Enxofre/genética , Homosserina/farmacologia , Pentanos/metabolismo , Polissacarídeos Bacterianos/genética , Polissacarídeos Bacterianos/metabolismo , Regiões Promotoras Genéticas , beta-Galactosidase/genética , beta-Galactosidase/metabolismo
12.
Cell Metab ; 25(2): 374-385, 2017 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-28178567

RESUMO

Elevated levels of branched-chain amino acids (BCAAs) have recently been implicated in the development of cardiovascular and metabolic diseases, but the molecular mechanisms are unknown. In a mouse model of impaired BCAA catabolism (knockout [KO]), we found that chronic accumulation of BCAAs suppressed glucose metabolism and sensitized the heart to ischemic injury. High levels of BCAAs selectively disrupted mitochondrial pyruvate utilization through inhibition of pyruvate dehydrogenase complex (PDH) activity. Furthermore, downregulation of the hexosamine biosynthetic pathway in KO hearts decreased protein O-linked N-acetylglucosamine (O-GlcNAc) modification and inactivated PDH, resulting in significant decreases in glucose oxidation. Although the metabolic remodeling in KO did not affect baseline cardiac energetics or function, it rendered the heart vulnerable to ischemia-reperfusion injury. Promoting BCAA catabolism or normalizing glucose utilization by overexpressing GLUT1 in the KO heart rescued the metabolic and functional outcome. These observations revealed a novel role of BCAA catabolism in regulating cardiac metabolism and stress response.


Assuntos
Aminoácidos de Cadeia Ramificada/metabolismo , Glucose/metabolismo , Miocárdio/metabolismo , Miocárdio/patologia , Traumatismo por Reperfusão/metabolismo , Acetilglucosamina/metabolismo , Animais , Glicosilação , Testes de Função Cardíaca , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias Cardíacas/metabolismo , Complexo Piruvato Desidrogenase/metabolismo , Ácido Pirúvico/metabolismo , Traumatismo por Reperfusão/fisiopatologia
13.
Phys Rev Lett ; 119(13): 136806, 2017 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-29341701

RESUMO

The quantum Hall effect is usually observed in 2D systems. We show that the Fermi arcs can give rise to a distinctive 3D quantum Hall effect in topological semimetals. Because of the topological constraint, the Fermi arc at a single surface has an open Fermi surface, which cannot host the quantum Hall effect. Via a "wormhole" tunneling assisted by the Weyl nodes, the Fermi arcs at opposite surfaces can form a complete Fermi loop and support the quantum Hall effect. The edge states of the Fermi arcs show a unique 3D distribution, giving an example of (d-2)-dimensional boundary states. This is distinctly different from the surface-state quantum Hall effect from a single surface of topological insulator. As the Fermi energy sweeps through the Weyl nodes, the sheet Hall conductivity evolves from the 1/B dependence to quantized plateaus at the Weyl nodes. This behavior can be realized by tuning gate voltages in a slab of topological semimetal, such as the TaAs family, Cd_{3}As_{2}, or Na_{3}Bi. This work will be instructive not only for searching transport signatures of the Fermi arcs but also for exploring novel electron gases in other topological phases of matter.

14.
J Mol Cell Cardiol ; 101: 90-98, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27832938

RESUMO

Branched chain α-keto acids (BCKAs) are endogenous metabolites of branched-chain amino acids (BCAAs). BCAA and BCKA are significantly elevated in pathologically stressed heart and contribute to chronic pathological remodeling and dysfunction. However, their direct impact on acute cardiac injury is unknown. Here, we demonstrated that elevated BCKAs significantly attenuated ischemia-reperfusion (I/R) injury and preserved post I/R function in isolated mouse hearts. BCKAs protected cardiomyocytes from oxidative stress-induced cell death in vitro. Mechanistically, BCKA protected oxidative stress induced cell death by inhibiting necrosis without affecting apoptosis or autophagy. Furthermore, BCKAs, but not BCAAs, protected mitochondria and energy production from oxidative injury. Finally, administration of BCKAs during reperfusion was sufficient to significantly attenuate cardiac I/R injury. These findings uncover an unexpected role of BCAA metabolites in cardioprotection against acute ischemia/reperfusion injury, and demonstrate the potential use of BCKA treatment to preserve ischemic tissue during reperfusion.


Assuntos
Aminoácidos de Cadeia Ramificada/metabolismo , Cetoácidos/metabolismo , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Estresse Oxidativo , Animais , Morte Celular , Linhagem Celular , Respiração Celular , Modelos Animais de Doenças , Metabolismo Energético , Humanos , Camundongos , Mitocôndrias/metabolismo , Miócitos Cardíacos/metabolismo , Necrose
15.
Biofabrication ; 8(4): 045014, 2016 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-27788123

RESUMO

The selective laser melting (SLM) technique is a recent additive manufacturing (AM) technique. Several studies have reported success in the SLM-based production of biocompatible orthopaedic implants and three-dimensional bone defect constructs. In this study, we evaluated the surface properties and biocompatibility of an SLM titanium implant in vitro and compared them with those of a machined (MA) titanium control surface. In addition, we evaluated the osseointegration capability of the SLM implants in vivo and compared it with those of MA and Nobel-speedy (Nobel-S) implants. SLM microtopographical surface analysis revealed porous and high roughness with varied geometry compared with a smooth surface in MA Ti samples but with similar favourable wettability. Osteoblast proliferation and alkaline phosphatase activity were significantly enhanced on the SLM surface. Histological analysis of the bone-implant contact ratio revealed no significant difference among SLM, MA, and Nobel-S implants. Micro-CT assessment indicated that there was no significant difference in bone volume fraction around the implant among SLM implants and other types of surface modification implants. The removal torque value measurement of SLM implants was significantly lower that of than Nobel-S implants P < 0.001 and higher than that of MA implants. The study demonstrates the capability of SLM implants to integrate with living bone. The SLM technique holds promise as a new dental implant manufacturing technique.


Assuntos
Substitutos Ósseos/química , Implantes Dentários , Lasers , Titânio/química , Animais , Medula Óssea/patologia , Substitutos Ósseos/farmacologia , Osso e Ossos/patologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cães , Camundongos , Microscopia Eletrônica de Varredura , Osseointegração/efeitos dos fármacos , Transição de Fase/efeitos da radiação , Propriedades de Superfície , Microtomografia por Raio-X
16.
Biochim Biophys Acta ; 1862(12): 2270-2275, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27639835

RESUMO

Metabolic remodeling is a hall-mark of cardiac maturation and pathology. The switch of substrate utilization from glucose to fatty acid is observed during post-natal maturation period in developing heart, but the process is reversed from fatty acids to glucose in the failing hearts across different clinic and experimental models. Majority of the current investigations have been focusing on the regulatory mechanism and functional impact of this metabolic reprogramming involving fatty acids and carbohydrates. Recent progress in metabolomics and transcriptomic analysis, however, revealed another significant remodeled metabolic branch associated with cardiac development and disease, i.e. Branched-Chain Amino Acid (BCAA) catabolism. These findings have established BCAA catabolic deficiency as a novel metabolic feature in failing hearts with potentially significant impact on the progression of pathological remodeling and dysfunction. In this review, we will evaluate the current evidence and potential implication of these discoveries in the context of heart diseases and novel therapies. This article is part of a Special Issue entitled: The role of post-translational protein modifications on heart and vascular metabolism edited by Jason R.B. Dyck & Jan F.C. Glatz.

17.
Mol Med Rep ; 14(1): 737-45, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27220358

RESUMO

There has been considerable focus in investigations on the delivery systems and clinical applications of bone morphogenetic protein­2 (BMP­2) for novel bone formation. However, current delivery systems require high levels of BMP­2 to exert a biological function. There are several concerns in using of high levels of BMP­2, including safety and the high cost of treatment. Therefore, the development of strategies to decrease the levels of BMP­2 required in these delivery systems is required. In our previous studies, a controlled­release system was developed, which used Traut's reagent and the cross­linker, 4­(N­maleimi­domethyl) cyclohexane­1­carboxylic acid 3­sulfo­N­hydroxysuccinimide ester sodium salt (Sulfo­SMCC), to chemically conjugate BMP­2 directly on collagen discs. In the current study, retention efficiency and release kinetics of stromal cell­derived factor­1α (SDF­1α) cross­linked on collagen scaffolds were detected. In addition, the osteogenic activity of SDF­1α and suboptimal doses of BMP­2 cross­linked on collagen discs following subcutaneous implantation in rats were evaluated. Independent two­tailed t­tests and one­way analysis of variance were used for analysis. In the present study, the controlled release of SDF­1α chemically conjugated on collagen scaffolds was demonstrated. By optimizing the concentrations of Traut's reagent and the Sulfo­SMCC cross­linker, a significantly higher level of SDF­1α was covalently retained on the collagen scaffold, compared with that retained using a physical adsorption method. Mesenchymal stem cell homing indicated that the biological function of the SDF­1α cross­linked on the collagen scaffolds remained intact. In rats, co­treatment with SDF­1α and a suboptimal dose of BMP­2 cross­linked on collagen scaffolds using this chemically conjugated method induced higher levels of ectopic bone formation, compared with the physical adsorption method. No ectopic bone formation was observed following treatment with a suboptimal dose of BMP­2 alone. Therefore, the co­delivery of SDF­1α and a suboptimal dose of BMP­2 chemically conjugated on collagen scaffolds for the treatment of bone injuries reduced the level of BMP­2 required, reducing the risks of side effects.


Assuntos
Proteína Morfogenética Óssea 2/administração & dosagem , Quimiocina CXCL12/administração & dosagem , Colágeno , Osteogênese/efeitos dos fármacos , Tecidos Suporte , Animais , Calcificação Fisiológica/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Preparações de Ação Retardada , Injeções Subcutâneas , Cinética , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Ratos
18.
Circulation ; 133(21): 2038-49, 2016 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-27059949

RESUMO

BACKGROUND: Although metabolic reprogramming is critical in the pathogenesis of heart failure, studies to date have focused principally on fatty acid and glucose metabolism. Contribution of amino acid metabolic regulation in the disease remains understudied. METHODS AND RESULTS: Transcriptomic and metabolomic analyses were performed in mouse failing heart induced by pressure overload. Suppression of branched-chain amino acid (BCAA) catabolic gene expression along with concomitant tissue accumulation of branched-chain α-keto acids was identified as a significant signature of metabolic reprogramming in mouse failing hearts and validated to be shared in human cardiomyopathy hearts. Molecular and genetic evidence identified the transcription factor Krüppel-like factor 15 as a key upstream regulator of the BCAA catabolic regulation in the heart. Studies using a genetic mouse model revealed that BCAA catabolic defect promoted heart failure associated with induced oxidative stress and metabolic disturbance in response to mechanical overload. Mechanistically, elevated branched-chain α-keto acids directly suppressed respiration and induced superoxide production in isolated mitochondria. Finally, pharmacological enhancement of branched-chain α-keto acid dehydrogenase activity significantly blunted cardiac dysfunction after pressure overload. CONCLUSIONS: BCAA catabolic defect is a metabolic hallmark of failing heart resulting from Krüppel-like factor 15-mediated transcriptional reprogramming. BCAA catabolic defect imposes a previously unappreciated significant contribution to heart failure.


Assuntos
Aminoácidos de Cadeia Ramificada/genética , Aminoácidos de Cadeia Ramificada/metabolismo , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/metabolismo , Animais , Insuficiência Cardíaca/patologia , Humanos , Masculino , Metabolismo/fisiologia , Metabolômica , Camundongos , Camundongos Knockout , Transcriptoma
19.
Sci Rep ; 6: 23944, 2016 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-27029511

RESUMO

Transcription factor carbohydrate responsive element binding protein (ChREBP) promotes glycolysis and lipogenesis in metabolic tissues and cancer cells. ChREBP-α and ChREBP-ß, two isoforms of ChREBP transcribed from different promoters, are both transcriptionally induced by glucose. However, the mechanism by which glucose increases ChREBP mRNA levels remains unclear. Here we report that hepatocyte nuclear factor 4 alpha (HNF-4α) is a key transcription factor for glucose-induced ChREBP-α and ChREBP-ß expression. Ectopic HNF-4α expression increased ChREBP transcription while knockdown of HNF-4α greatly reduced ChREBP mRNA levels in liver cancer cells and mouse primary hepatocytes. HNF-4α not only directly bound to an E-box-containing region in intron 12 of the ChREBP gene, but also promoted ChREBP-ß transcription by directly binding to two DR1 sites and one E-box-containing site of the ChREBP-ß promoter. Moreover, HNF-4α interacted with ChREBP-α and synergistically promoted ChREBP-ß transcription. Functionally, HNF-4α suppression reduced glucose-dependent ChREBP induction. Increased nuclear abundance of HNF-4α and its binding to cis-elements of ChREBP gene in response to glucose contributed to glucose-responsive ChREBP transcription. Taken together, our results not only revealed the novel mechanism by which HNF-4α promoted ChREBP transcription in response to glucose, but also demonstrated that ChREBP-α and HNF-4α synergistically increased ChREBP-ß transcription.


Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Glucose/farmacologia , Fator 4 Nuclear de Hepatócito/genética , Hepatócitos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Ativação Transcricional/efeitos dos fármacos , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Genes Reporter , Glucose/metabolismo , Células HEK293 , Células Hep G2 , Fator 4 Nuclear de Hepatócito/metabolismo , Hepatócitos/citologia , Hepatócitos/metabolismo , Humanos , Fígado/citologia , Fígado/metabolismo , Luciferases/genética , Luciferases/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Motivos de Nucleotídeos , Cultura Primária de Células , Regiões Promotoras Genéticas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais
20.
Int J Nanomedicine ; 11: 1147-58, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27042064

RESUMO

OBJECTIVE: To compare the direct osteogenic effect between placental growth factor-2 (PlGF-2) and bone morphogenic protein-2 (BMP-2). METHODS: Three groups of PlGF-2/BMP-2-loaded heparin-N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) nanocomplexes were prepared: those with 0.5 µg PlGF-2; with 1.0 µg BMP-2; and with 0.5 µg PlGF-2 combined with 1.0 µg BMP-2. The loading efficiencies and release profiles of these growth factors (GFs) in this nanocomplex system were quantified using enzyme-linked immunosorbent assay, their biological activities were evaluated using cell counting kit-8, cell morphology, and cell number counting assays, and their osteogenic activities were quantified using alkaline phosphatase and Alizarin Red S staining assays. RESULTS: The loading efficiencies were more than 99% for the nanocomplexes loaded with just PlGF-2 and for those loaded with both PlGF-2 and BMP-2. For the nanocomplex loaded with just BMP-2, the loading efficiency was more than 97%. About 83%-84% of PlGF-2 and 89%-91% of BMP-2 were stably retained on the nanocomplexes for at least 21 days. In in vitro biological assays, PlGF-2 exhibited osteogenic effects comparable to those of BMP-2 despite its dose in the experiments being lower than that of BMP-2. Moreover, the results implied that heparin-based nanocomplexes encapsulating two GFs have enhanced potential in the enhancement of osteoblast function. CONCLUSION: PlGF-2-loaded heparin-HTCC nanocomplexes may constitute a promising system for bone regeneration. Moreover, the dual delivery of PlGF-2 and BMP-2 appears to have greater potential in bone tissue regeneration than the delivery of either GFs alone.


Assuntos
Proteína Morfogenética Óssea 2/farmacocinética , Heparina/química , Nanocompostos/química , Osteogênese/efeitos dos fármacos , Fator de Crescimento Placentário/farmacocinética , Células 3T3 , Animais , Proteína Morfogenética Óssea 2/farmacologia , Regeneração Óssea , Quitosana/análogos & derivados , Quitosana/química , Ensaio de Imunoadsorção Enzimática , Heparina/farmacologia , Camundongos , Fator de Crescimento Placentário/farmacologia
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