RESUMEN
It is necessary to develop novel and efficient alternatives to fluorocarbon surfactant and prepare fluorine-free environmentally-friendly fire extinguishing agent. The carboxyl modified polyether polysiloxane surfactant (CMPS) with high surface activity was synthesized via the esterification reaction using hydroxyl-containing polyether modified polysiloxane (HPMS) and maleic anhydride (MA) as raw materials. The process conditions of the esterification reaction were optimized by orthogonal tests, and the optimum process parameters were determined as follows: reaction temperature of 85 °C, reaction time of 4.5 h, isopropyl alcohol content of 20% and the molar ratio of HPMS/MA of 1/1. The chemical structure, surface activity, aggregation behavior, foam properties, wetting properties and electron distribution were systematically investigated. It was found that the carboxyl group was successfully grafted into silicone molecule, and the conjugated system was formed, which changed the interaction force between the molecules and would affect the surface activity of the aqueous solution. The CMPS exhibited excellent surface activity and could effectively reduce the water's surface tension to 18.46 mN/m. The CMPS formed spherical aggregates in aqueous solution, and the contact angle value of CMPS is 15.56°, illustrating that CMPS had excellent hydrophilicity and wetting performance. The CMPS can enhance the foam property and has good stability. The electron distribution results indicate that the introduced carboxyl groups are more inclined towards the negative charge band, which would be conducive to weak the interaction between molecules and improve the surface activity of the solution. Consequently, new foam fire extinguishing agents were prepared by using CMPS as a key component and they exhibited excellent fire-fighting performance. The prepared CMPS would be the optimal alternative to fluorocarbon surfactant and could be applied in foam extinguishing agents.
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Thirty-two novel DG F-spiroacetal ring-opening derivatives, including 24 acetylated derivatives and 8 nitrogenous derivatives, were designed and synthesized from diosgenin (DG). The cytotoxicity of the novel derivatives was evaluated by MTT assay, except for compounds 4a, 4e, 4i, 4 l, 5a and 5 h, which were potentially cytotoxic to RAW264.7 cells, all the other derivatives had no significant cytotoxicity. The NO release inhibitory activities of novel derivatives were screened by Griess method. The results showed that the anti-inflammatory activity of the DG acetylated derivatives was stronger than the nitrogenous derivatives, and 4a-4 m containing acetyl groups at the 3-position may have better anti-inflammatory effects than 5a-5 k containing free hydroxyl groups. In ELISA assay, compound 4 m exhibited potent anti-inflammatory activity by inhibiting the production of NO in RAW264.7 cells activated by LPS with IC50 values 0.449 ± 0.050 µM. The results of docking experiments showed that 4 m has a good affinity for p65 protein.
Asunto(s)
Antineoplásicos , Diosgenina , Antiinflamatorios/farmacología , Antineoplásicos/farmacología , Diosgenina/farmacología , Diseño de Fármacos , Simulación del Acoplamiento Molecular , Estructura Molecular , Relación Estructura-ActividadRESUMEN
Acinetobacter baumannii is currently posing a serious threat to global health. Lipopolysaccharide (LPS) is a potent virulence factor of pathogenic Gram-negative bacteria. To explore the antigenic properties of A.â baumannii LPS, four Kdo-containing inner core glycans from A.â baumannii strain ATCC 17904 were synthesized. A flexible and divergent method based on the use of the orthogonally substituted α-Kdo-(2â5)-Kdo disaccharides was developed. Selective removal of different protecting groups in these key precursors and elongation of sugar chain via α-stereocontrolled coupling with 5,7-O-di-tert-butylsilylene or 5-O-benzoyl protected Kdo thioglycosides and 2-azido-2-deoxyglucosyl thioglycoside allowed efficient assembly of the target molecules. Glycan microarray analysis of sera from infected patients revealed that the 4,5-branched Kdo trimer was a potential antigenic epitope, which is attractive for further immunological research to develop carbohydrate vaccines against A.â baumannii.
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Acinetobacter baumannii , Lipopolisacáridos , Carbohidratos , Disacáridos/química , Humanos , Lipopolisacáridos/química , Oligosacáridos/química , PolisacáridosRESUMEN
Nuclear factor κB (NF-κB) is a transcription factor important for regulating innate and adaptive immunity, cellular proliferation, apoptosis, and senescence. Dysregulation of NF-κB and its upstream regulator IκB kinase (IKK) contributes to the pathogenesis of multiple inflammatory and degenerative diseases as well as cancer. An 11-amino acid peptide containing the NF-κB essential modulator (NEMO)-binding domain (NBD) derived from the C-terminus of ß subunit of IKK, functions as a highly selective inhibitor of the IKK complex by disrupting the association of IKKß and the IKKγ subunit NEMO. A structure-based pharmacophore model was developed to identify NBD mimetics by in silico screening. Two optimized lead NBD mimetics, SR12343 and SR12460, inhibited tumor necrosis factor α (TNF-α)- and lipopolysaccharide (LPS)-induced NF-κB activation by blocking the interaction between IKKß and NEMO and suppressed LPS-induced acute pulmonary inflammation in mice. Chronic treatment of a mouse model of Duchenne muscular dystrophy (DMD) with SR12343 and SR12460 attenuated inflammatory infiltration, necrosis and muscle degeneration, demonstrating that these small-molecule NBD mimetics are potential therapeutics for inflammatory and degenerative diseases.
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Materiales Biomiméticos/farmacología , Quinasa I-kappa B/antagonistas & inhibidores , Distrofia Muscular de Duchenne/tratamiento farmacológico , Neumonía/tratamiento farmacológico , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Animales , Materiales Biomiméticos/química , Línea Celular , Femenino , Células HEK293 , Humanos , Quinasa I-kappa B/química , Quinasa I-kappa B/metabolismo , Inflamación/tratamiento farmacológico , Lipopolisacáridos , Ratones , Ratones Endogámicos C57BL , Necrosis/tratamiento farmacológico , Dominios Proteicos , Células RAW 264.7RESUMEN
Although the lack of dystrophin expression in muscle myofibers is the central cause of Duchenne muscular dystrophy (DMD), accumulating evidence suggests that DMD may also be a stem cell disease. Recent studies have revealed dystrophin expression in satellite cells and demonstrated that dystrophin deficiency is directly related to abnormalities in satellite cell polarity, asymmetric division, and epigenetic regulation, thus contributing to the manifestation of the DMD phenotype. Although metabolic and mitochondrial dysfunctions have also been associated with the DMD pathophysiology profile, interestingly, the role of dystrophin with respect to stem cells dysfunction has not been elucidated. In the past few years, editing of the gene that encodes dystrophin has emerged as a promising therapeutic approach for DMD, although the effects of dystrophin restoration in stem cells have not been addressed. Herein, we describe our use of a clustered regularly interspaced short palindromic repeats/Cas9-based system to correct the dystrophin mutation in dystrophic (mdx) muscle progenitor cells (MPCs) and show that the expression of dystrophin significantly improved cellular properties of the mdx MPCs in vitro. Our findings reveal that dystrophin-restored mdx MPCs demonstrated improvements in cell proliferation, differentiation, bioenergetics, and resistance to oxidative and endoplasmic reticulum stress. Furthermore, our in vivo studies demonstrated improved transplantation efficiency of the corrected MPCs in the muscles of mdx mice. Our results indicate that changes in cellular energetics and stress resistance via dystrophin restoration enhance muscle progenitor cell function, further validating that dystrophin plays a role in stem cell function and demonstrating the potential for new therapeutic approaches for DMD. Stem Cells 2019;37:1615-1628.
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Distrofina/genética , Terapia Genética/métodos , Fibras Musculares Esqueléticas/patología , Distrofia Muscular de Duchenne/terapia , Células Satélite del Músculo Esquelético/patología , Animales , Sistemas CRISPR-Cas/genética , Diferenciación Celular/genética , Polaridad Celular/fisiología , Proliferación Celular/genética , Modelos Animales de Enfermedad , Distrofina/metabolismo , Estrés del Retículo Endoplásmico/genética , Metabolismo Energético/genética , Epigénesis Genética , Edición Génica , Ratones , Ratones Endogámicos mdx , Fibras Musculares Esqueléticas/metabolismo , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/patología , Estrés Oxidativo/genética , Células Madre/fisiologíaRESUMEN
Recent efforts have focused on customizing orthobiologics, such as platelet-rich plasma (PRP) and bone marrow concentrate (BMC), to improve tissue repair. We hypothesized that oral losartan (a TGF-ß1 blocker with anti-fibrotic properties) could decrease TGF-ß1 levels in leukocyte-poor PRP (LP-PRP) and fibrocytes in BMC. Ten rabbits were randomized into two groups (N = 5/group): osteochondral defect + microfracture (control, group 1) and osteochondral defect + microfracture + losartan (losartan, group 2). For group 2, a dose of 10mg/kg/day of losartan was administrated orally for 12 weeks post-operatively. After 12 weeks, whole blood (WB) and bone marrow aspirate (BMA) samples were collected to process LP-PRP and BMC. TGF-ß1 concentrations were measured in WB and LP-PRP with multiplex immunoassay. BMC cell populations were analyzed by flow cytometry with CD31, CD44, CD45, CD34, CD146 and CD90 antibodies. There was no significant difference in TGF-ß1 levels between the losartan and control group in WB or LP-PRP. In BMC, the percentage of CD31+ cells (endothelial cells) in the losartan group was significantly higher than the control group (p = 0.008), while the percentage of CD45+ cells (hematopoietic cells-fibrocytes) in the losartan group was significantly lower than the control group (p = 0.03).
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Fibroblastos/efectos de los fármacos , Fibrosis/prevención & control , Losartán/farmacología , Factor de Crecimiento Transformador beta1/antagonistas & inhibidores , Cicatrización de Heridas/efectos de los fármacos , Administración Oral , Bloqueadores del Receptor Tipo 1 de Angiotensina II/administración & dosificación , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Bloqueadores del Receptor Tipo 1 de Angiotensina II/uso terapéutico , Animales , Antihipertensivos/administración & dosificación , Antihipertensivos/farmacología , Antihipertensivos/uso terapéutico , Células de la Médula Ósea , Transición Epitelial-Mesenquimal , Fibroblastos/metabolismo , Fibrosis/metabolismo , Antígenos Comunes de Leucocito/análisis , Losartán/administración & dosificación , Losartán/uso terapéutico , Plasma Rico en Plaquetas , Conejos , Transducción de Señal , Factor de Crecimiento Transformador beta1/metabolismoRESUMEN
Glucocorticoid treatment represents a standard palliative treatment for Duchenne muscular dystrophy (DMD) patients, but various adverse effects have limited this treatment. In an effort to understand the mechanism(s) by which glucocorticoids impart their effects on the dystrophic muscle, and potentially reduce the adverse effects, we have studied the effect of prednisolone treatment in dystrophin/utrophin double knockout (dKO) mice, which exhibit a severe dystrophic phenotype due to rapid muscle stem cell depletion. Our results indicate that muscle stem cell depletion in dKO muscle is related to upregulation of mTOR, and that prednisolone treatment reduces the expression of mTOR and other pro-inflammatory mediators, consequently slowing down muscle stem cell depletion. However, prednisolone treatment was unable to improve the myogenesis of stem cells and reduce fibrosis in dKO muscle. We then studied whether glucocorticoid treatment can be improved by co-administration of an inhibitor of RhoA/ROCK signaling, which can be activated by glucocorticoids and was found in our previous work to be over-activated in dystrophic muscle. Our results indicate that the combination of RhoA/ROCK inhibition and glucocorticoid treatment in dystrophic muscle have a synergistic effect in alleviating the dystrophic phenotype. Taken together, our study not only shed light on the mechanism by which glucocorticoid imparts its beneficial effect on dystrophic muscle, but also revealed the synergistic effect of RhoA/ROCK inhibition and glucocorticoid treatment, which could lead to the development of more efficient therapeutic approaches for treating DMD patients.
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Distrofina/metabolismo , Glucocorticoides/metabolismo , Utrofina/metabolismo , Animales , Modelos Animales de Enfermedad , Distrofina/genética , Glucocorticoides/uso terapéutico , Ratones , Ratones Endogámicos mdx , Ratones Noqueados , Músculo Esquelético/metabolismo , Distrofia Muscular de Duchenne/metabolismo , Distrofia Muscular de Duchenne/terapia , Prednisolona/uso terapéutico , Transducción de Señal , Células Madre/metabolismo , Utrofina/genética , Proteína de Unión al GTP rhoA/metabolismoRESUMEN
Although it has been speculated that stem cell depletion plays a role in the rapid progression of the muscle histopathology associated with Duchenne Muscular Dystrophy (DMD), the molecular and cellular mechanisms responsible for stem cell depletion remain poorly understood. The rapid depletion of muscle stem cells has not been observed in the dystrophin-deficient model of DMD (mdx mouse), which may explain the relatively mild dystrophic phenotype observed in this animal model. In contrast, we have observed a rapid occurrence of stem cell depletion in the dystrophin/utrophin double knockout (dKO) mouse model, which exhibits histopathological features that more closely recapitulate the phenotype observed in DMD patients compared with the mdx mouse. Notch signaling has been found to be a key regulator of stem cell self-renewal and myogenesis in normal skeletal muscle; however, little is known about the role that Notch plays in the development of the dystrophic histopathology associated with DMD. Our results revealed an over-activation of Notch in the skeletal muscles of dKO mice, which correlated with sustained inflammation, impaired muscle regeneration and the rapid depletion and senescence of the muscle progenitor cells (MPCs, i.e. Pax7+ cells). Consequently, the repression of Notch in the skeletal muscle of dKO mice delayed/reduced the depletion and senescence of MPCs, and restored the myogenesis capacity while reducing inflammation and fibrosis. We suggest that the down-regulation of Notch could represent a viable approach to reduce the dystrophic histopathologies associated with DMD.
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Distrofina/genética , Distrofia Muscular de Duchenne/patología , Mioblastos Esqueléticos/patología , Receptores Notch/metabolismo , Transducción de Señal , Utrofina/genética , Animales , Modelos Animales de Enfermedad , Técnicas de Inactivación de Genes , Ratones , Ratones Noqueados , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/metabolismo , Mioblastos Esqueléticos/metabolismo , Receptores Notch/fisiologíaRESUMEN
Duchenne muscular dystrophy (DMD) patients lack dystrophin from birth; however, muscle weakness becomes apparent only at 3-5 years of age, which happens to coincide with the depletion of the muscle progenitor cell (MPC) pools. Indeed, MPCs isolated from older DMD patients demonstrate impairments in myogenic potential. To determine whether the progression of muscular dystrophy is a consequence of the decline in functional MPCs, we investigated two animal models of DMD: (i) dystrophin-deficient mdx mice, the most commonly utilized model of DMD, which has a relatively mild dystrophic phenotype and (ii) dystrophin/utrophin double knock-out (dKO) mice, which display a similar histopathologic phenotype to DMD patients. In contrast to age-matched mdx mice, we observed that both the number and regeneration potential of dKO MPCs rapidly declines during disease progression. This occurred in MPCs at both early and late stages of myogenic commitment. In fact, early MPCs isolated from 6-week-old dKO mice have reductions in proliferation, resistance to oxidative stress and multilineage differentiation capacities compared with age-matched mdx MPCs. This effect may potentially be mediated by fibroblast growth factor overexpression and/or a reduction in telomerase activity. Our results demonstrate that the rapid disease progression in the dKO model is associated, at least in part, with MPC depletion. Therefore, alleviating MPC depletion could represent an approach to delay the onset of the histopathologies associated with DMD patients.
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Distrofina/genética , Distrofias Musculares/patología , Mioblastos Esqueléticos/patología , Utrofina/genética , Animales , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Humanos , Ratones , Ratones Endogámicos mdx , Ratones Noqueados , Distrofias Musculares/genética , Mioblastos Esqueléticos/fisiología , RegeneraciónRESUMEN
Although we recognize the many advantages of improved musculoskeletal health, we also note that our ability to sustain this health and to maintain quality of life in an aging population is currently deficient. However, global efforts have produced numerous advances in tissue engineering and regenerative medicine that will collectively serve to fill this deficiency in the near future. The purpose of this review is to highlight our current knowledge, to outline our recent advances, and to discuss the evolving paradigms in skeletal muscle injury and repair.
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Músculo Esquelético/lesiones , Músculo Esquelético/patología , Cicatrización de Heridas , Animales , Fibrosis , Humanos , Músculo Esquelético/irrigación sanguínea , Neovascularización Fisiológica , Regeneración , Trasplante de Células MadreRESUMEN
A laser diode (LD) cladding pumped single-mode 1030 nm laser has been demonstrated, in an adhesive-free bonded 40 µm core Yb:YAG crystalline fiber waveguide (CFW). A laser output power of 13.2 W at a wavelength of 1.03 µm has been achieved, for an input pump power of 39.5 W. The corresponded laser efficiency is 33.4%. The laser beam quality is confirmed to be near diffraction-limited, with a measured M2 = 1.02. A LD core pumped single-clad Yb:YAG CFW laser has also been demonstrated with a top-hat laser beam profile, with a laser output power of 28 W and a slope efficiency of 78%.
RESUMEN
Heterotopic ossification (HO) and fatty infiltration (FI) often occur in diseased skeletal muscle and have been previously described in various animal models of Duchenne muscular dystrophy (DMD); however, the pathological mechanisms remain largely unknown. Dystrophin-deficient mdx mice and dystrophin/utrophin double-knockout (dKO) mice are mouse models of DMD; however, mdx mice display a strong muscle regeneration capacity, while dKO mice exhibit a much more severe phenotype, which is similar to patients with DMD. Our results revealed that more extensive HO, but not FI, occurred in the skeletal muscle of dKO mice versus mdx mice, and RhoA activation specifically occurred at the sites of HO. Moreover, the gene expression of RhoA, BMPs, and several inflammatory factors were significantly up-regulated in muscle stem cells isolated from dKO mice; while inactivation of RhoA in the cells with RhoA/ROCK inhibitor Y-27632 led to reduced osteogenic potential and improved myogenic potential. Finally, inactivation of RhoA signaling in the dKO mice with Y-27632 improved muscle regeneration and reduced the expression of BMPs, inflammation, HO, and intramyocellular lipid accumulation in both skeletal and cardiac muscle. Our results revealed that RhoA represents a major molecular switch in the regulation of HO and muscle regeneration in dystrophic skeletal muscle of mice.
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Distrofina/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Proteínas de Unión al GTP rho/metabolismo , Animales , Benzopiranos/farmacología , Diferenciación Celular/genética , Diferenciación Celular/fisiología , Células Cultivadas , Modelos Animales de Enfermedad , Distrofina/deficiencia , Distrofina/genética , Ratones , Ratones Noqueados , Distrofia Muscular Animal/genética , Distrofia Muscular Animal/metabolismo , Osificación Heterotópica/genética , Osificación Heterotópica/metabolismo , Utrofina/deficiencia , Utrofina/genética , Utrofina/metabolismo , Proteínas de Unión al GTP rho/antagonistas & inhibidores , Proteína de Unión al GTP rhoARESUMEN
BACKGROUND: Epigenetics is the study of changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence. It is widely accepted that cancer has genetic and epigenetic origins. The idea of epigenetic reprogramming of cancer cells by an embryonic microenvironment possesses potential interest from the prospect of both basic science and potential therapeutic strategies. Chick embryo extract (CEE) has been used for the successful expansion of many specific stem cells and has demonstrated the ability to facilitate DNA demethylation. QUESTIONS/PURPOSES: The current study was conducted to compare the status of DNA methylation in highly metastatic and less metastatic osteosarcoma cells and to investigate whether CEE may affect the epigenetic regulation of tumor suppressor genes and thus change the metastatic phenotypes of highly metastatic osteosarcoma cells. METHODS: K7M2 murine OS cells were treated with CEE to determine its potential effect on DNA methylation, cell apoptosis, and invasion capacity. RESULTS: Our current results suggest that the methylation status of tumor suppressor genes (p16, p53, and E-cadherin) is significantly greater in highly metastatic mouse ostoesarcoma K7M2 cells in comparison with less metastatic mouse osteosarcoma K12 cells. CEE treatment of K7M2 cells caused demethylation of p16, p53, and E-cadherin genes, upregulated their expression, and resulted in the reversion of metastatic phenotypes in highly metastatic osteosarcoma cells. CONCLUSIONS: CEE may promote the reversion of metastatic phenotypes of osteosarcoma cells and can be a helpful tool to study osteosarcoma tumor reversion by epigenetic reprogramming. CLINICAL RELEVANCE: Demethylation of tumor suppressor genes in osteosarcoma may represent a novel strategy to diminish the metastatic potential of this neoplasm. Further studies, both in vitro and in vivo, are warranted to evaluate the clinical feasibility of this approach as an adjuvant to current therapy.
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Neoplasias Óseas/genética , Metilación de ADN/efectos de los fármacos , Epigénesis Genética/efectos de los fármacos , Genes Supresores de Tumor , Osteosarcoma/genética , Extractos de Tejidos/farmacología , Animales , Antígenos CD , Neoplasias Óseas/patología , Cadherinas/genética , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Embrión de Pollo , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Genes p16 , Genes p53 , Genotipo , Ratones , Invasividad Neoplásica , Osteosarcoma/secundario , Fenotipo , Factores de TiempoRESUMEN
The mechanism regulating cellular senescence of postmitotic muscle cells is still unknown. cGAS-STING innate immune signaling was found to mediate cellular senescence in various types of cells, including postmitotic neuron cells, which however has not been explored in postmitotic muscle cells. Here by studying the myofibers from Zmpste24-/- progeria aged mice [an established mice model for Hutchinson-Gilford progeria syndrome (HGPS)], we observed senescence-associated phenotypes in Zmpste24-/- myofibers, which is coupled with increased oxidative damage to mitochondrial DNA (mtDNA) and secretion of senescence-associated secretory phenotype (SASP) factors. Also, Zmpste24-/- myofibers feature increased release of mtDNA from damaged mitochondria, mitophagy dysfunction, and activation of cGAS-STING. Meanwhile, increased mtDNA release in Zmpste24-/- myofibers appeared to be related with increased VDAC1 oligomerization. Further, the inhibition of VDAC1 oligomerization in Zmpste24-/- myofibers with VBIT4 reduced mtDNA release, cGAS-STING activation, and the expression of SASP factors. Our results reveal a novel mechanism of innate immune activation-associated cellular senescence in postmitotic muscle cells in aged muscle, which may help identify novel sets of diagnostic markers and therapeutic targets for progeria aging and aging-associated muscle diseases.
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Senescencia Celular , ADN Mitocondrial , Proteínas de la Membrana , Nucleotidiltransferasas , Animales , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , ADN Mitocondrial/metabolismo , ADN Mitocondrial/genética , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Ratones , Progeria/metabolismo , Progeria/patología , Progeria/genética , Transducción de Señal , Canal Aniónico 1 Dependiente del Voltaje/metabolismo , Canal Aniónico 1 Dependiente del Voltaje/genética , Ratones Noqueados , Células Musculares/metabolismo , Mitofagia , Mitocondrias/metabolismo , Humanos , Ratones Endogámicos C57BL , MetaloendopeptidasasRESUMEN
Broadband and polarization-insensitive phase conjugation, achieved based on difference-frequency generation in a second-order nonlinear composite consisting of stacked KTiOPO(4) (KTP) plates, was exploited to restore blurred images due to phase distortion as a novel scheme. Due to the quasi-phase matching in the stacked KTP crystals, our result reveals that the image restoration is insensitive to the polarization direction and wavelength of the input beam.
RESUMEN
Granulin-epithelin precursor (GEP) is an autocrine growth factor that has been implicated in embryonic development, tissue repair, tumorigenesis, and inflammation. Here we report that GEP was expressed in skeletal muscle tissue and its level was differentially altered in the course of C2C12 myoblast fusion. The GEP expression during myoblast fusion was a consequence of MyoD transcription factor binding to several E-box (CANNTG) sequences in the 5'-flanking regulatory region of GEP gene, followed by transcription. Recombinant GEP potently inhibited myotube formation from C2C12 myoblasts whereas the knockdown of endogenous of GEP via a siRNA approach accelerated the fusion of myoblasts to myotubes. Interestingly, the muscle fibers of GEP knockdown mice were larger in number but noticeably smaller in size when compared to the wild-type. Mechanistic studies revealed that during myoblast fusion, the addition of GEP led to remarkable reductions in the expressions of muscle-specific transcription factors, including MyoD. In addition, the regulation of myotube formation by GEP is mediated by the anti-myogenic factor JunB, which is upregulated following GEP stimulation. Thus, GEP growth factor, JunB, and MyoD transcription factor form a regulatory loop and act in concert in the course of myogenesis.
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Retroalimentación Fisiológica , Péptidos y Proteínas de Señalización Intercelular/fisiología , Proteína MioD/metabolismo , Mioblastos Esqueléticos/metabolismo , Animales , Secuencia de Bases , Sitios de Unión , Diferenciación Celular , Línea Celular , Granulinas , Células HEK293 , Humanos , Péptidos y Proteínas de Señalización Intercelular/química , Péptidos y Proteínas de Señalización Intercelular/genética , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Ratones , Datos de Secuencia Molecular , Fibras Musculares Esqueléticas/citología , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/citología , Músculo Esquelético/metabolismo , ProgranulinasRESUMEN
Recent studies indicate that ß-elemene, a compound isolated from the Chinese herbal medicine Curcuma wenyujin, is capable of reversing tumor MDR, although the mechanism remains elusive. In this study, ß-Elemene treatment markedly increased the intracellular accumulation of doxorubicin (DOX) and rhodamine 123 in both K562/DNR and SGC7901/ADR cells and significantly inhibited the expression of P-gp. Treatment of SGC7901/ADR cells with ß-elemene led to downregulation of Akt phosphorylation and significant upregulation of the E3 ubiquitin ligases, c-Cbl and Cbl-b. Importantly, ß-elemene significantly enhanced the anti-tumor activity of DOX in nude mice bearing SGC7901/ADR xenografts. Taken together, our results suggest that ß-elemene may target P-gp-overexpressing leukemia and gastric cancer cells to enhance the efficacy of DOX treatment.
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Proteínas Adaptadoras Transductoras de Señales/metabolismo , Antineoplásicos/uso terapéutico , Doxorrubicina/uso terapéutico , Resistencia a Antineoplásicos/efectos de los fármacos , Proteínas Proto-Oncogénicas c-cbl/metabolismo , Sesquiterpenos/uso terapéutico , Neoplasias Gástricas/tratamiento farmacológico , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Animales , Antineoplásicos/farmacología , Línea Celular Tumoral , Curcuma/química , Doxorrubicina/farmacología , Resistencia a Múltiples Medicamentos/efectos de los fármacos , Mucosa Gástrica/metabolismo , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Sesquiterpenos/farmacología , Transducción de Señal/efectos de los fármacos , Estómago/efectos de los fármacos , Neoplasias Gástricas/metabolismoRESUMEN
299In Duchenne muscular dystrophy, dystrophic muscle phenotypes are closely associated with the exhaustion of muscle stem cells. Transplantation of muscle stem cells has been widely studied for improving muscle regeneration, but poor cell survival and self-renewal, rapid loss of stemness, and limited dispersion of grafted cells following transplantation have collectively hindered the overall success of this strategy. Optimized mechanisms for maintaining and improving stem cell function are naturally present in the microenvironment of the stem cell niche in healthy muscles. Therefore, one logical strategy toward improving stem cell function and efficiency of stem cell transplantation in diseased muscles would be the establishment of a microenvironment mimicking some key aspects of healthy native stem cell niches. Here, we applied inkjet-based bioprinting technology to engineer a mimicked artificial stem cell niche in dystrophic muscle, comprising stem cell niche regulating factors (Notch activator DLL1) bioprinted onto 3D DermaMatrix construct. The recombinant DLL1 protein, DLL1 (mouse): Fc (human) (rec), was applied here as the Notch activator. Bioprinted DermaMatrix construct was seeded with muscle stem cells in vitro, and increased stem cell maintenance and repressed myogenic differentiation process was observed. DLL1 bioprinted DermaMatrix construct was then engrafted into dystrophic muscle of mdx/scid mice, and the improved cell engraftment and progression of muscle regeneration was observed 10 days after engraftment. Our results demonstrated that bioprinting of Notch activator within 3D construct can be applied to serve as muscle stem cell niche and improve the efficacy of muscle stem cell transplantation in diseased muscle.
RESUMEN
Aging leads to several geriatric conditions including osteoporosis (OP) and associated frailty syndrome. Treatments for these conditions are limited and none target fundamental drivers of pathology, and thus identifying strategies to delay progressive loss of tissue homeostasis and functional reserve will significantly improve quality of life in elderly individuals. A fundamental property of aging is the accumulation of senescent cells. Senescence is a cell state defined by loss of proliferative capacity, resistance to apoptosis, and the release of a proinflammatory and anti-regenerative senescence-associated secretory phenotype (SASP). The accumulation of senescent cells and SASP factors is thought to significantly contribute to systemic aging. Senolytics-compounds which selectively target and kill senescent cells-have been characterized to target and inhibit anti-apoptotic pathways that are upregulated during senescence, which can elicit apoptosis in senescent cells and relieve SASP production. Senescent cells have been linked to several age-related pathologies including bone density loss and osteoarthritis in mice. Previous studies in murine models of OP have demonstrated that targeting senescent cells pharmacologically with senolytic drugs can reduce symptomology of the disease. Here, we demonstrate the efficacy of senolytic drugs (dasatinib, quercetin, and fisetin) to improve age-associated degeneration in bone using the Zmpste24-/- (Z24-/-) progeria murine system for Hutchinson-Gilford progeria syndrome (HGPS). We found that the combination of dasatinib plus quercetin could not significantly mitigate trabecular bone loss although fisetin administration could reduce bone density loss in the accelerated aging Z24-/- model. Furthermore, the overt bone density loss observed in the Z24-/- model reported herein highlights the Z24 model as a translational model to recapitulate alterations in bone density associated with advanced age. Consistent with the "geroscience hypothesis," these data demonstrate the utility of targeting a fundamental driver of systemic aging (senescent cell accumulation) to alleviate a common condition with age, bone deterioration.
RESUMEN
Nuclear decoupling and softening are the main cellular mechanisms to resist mechanical stress-induced nuclear/DNA damage, however, its molecular mechanisms remain much unknown. Our recent study of Hutchinson-Gilford progeria syndrome (HGPS) disease revealed the role of nuclear membrane protein Sun2 in mediating nuclear damages and cellular senescence in progeria cells. However, the potential role of Sun2 in mechanical stress-induced nuclear damage and its correlation with nuclear decoupling and softening is still not clear. By applying cyclic mechanical stretch to mesenchymal stromal cells (MSCs) of WT and Zmpset24-/- mice (Z24-/-, a model for HGPS), we observed much increased nuclear damage in Z24-/- MSCs, which also featured elevated Sun2 expression, RhoA activation, F-actin polymerization and nuclear stiffness, indicating the compromised nuclear decoupling capacity. Suppression of Sun2 with siRNA effectively reduced nuclear/DNA damages caused by mechanical stretch, which was mediated by increased nuclear decoupling and softening, and consequently improved nuclear deformability. Our results reveal that Sun2 is greatly involved in mediating mechanical stress-induced nuclear damage by regulating nuclear mechanical properties, and Sun2 suppression can be a novel therapeutic target for treating progeria aging or aging-related diseases.