RESUMEN
It has been documented that caspase 3 activity is necessary for skeletal muscle regeneration, but how its activity is regulated is largely unknown. Our previous report shows that intracellular TMEM16A, a calcium activated chloride channel, significantly regulates caspase 3 activity in myoblasts during skeletal muscle development. By using a mouse line with satellite cell (SC)-specific deletion of TMEM16A, we examined the role of TMEM16A in regulating caspase 3 activity in SC (or SC-derived myoblast) as well as skeletal muscle regeneration. The mutant animals displayed apparently impaired regeneration capacity in adult muscle along with enhanced ER stress and elevated caspase 3 activity in Tmem16a-/- SC derived myoblasts. Blockade of either excessive ER stress or caspase 3 activity by small molecules significantly restored the inhibited myogenic differentiation of Tmem16a-/- SCs, indicating that excessive caspase 3 activity resulted from TMEM16A deletion contributes to the impaired muscle regeneration and the upstream regulator of caspase 3 was ER stress. Our results revealed an essential role of TMEM16A in satellite cell mediated skeletal muscle regeneration by ensuring a moderate level of caspase 3 activity.
RESUMEN
Both chronic obstructive pulmonary disease (COPD) and asthma are severe respiratory diseases. Bitter receptor-mediated bronchodilation is a potential therapy for asthma, but the mechanism underlying the agonistic relaxation of airway smooth muscle (ASM) is not well defined. By exploring the ASM relaxation mechanism of bitter substances, we observed that pretreatment with the bitter substances nearly abolished the methacholine (MCh)-induced increase in the ASM cell (ASMC) calcium concentration, thereby suppressing the calcium-induced contraction release. The ASM relaxation was significantly inhibited by simultaneous deletion of three Gαt proteins, suggesting an interaction between Tas2R and AChR signaling cascades in the relaxation process. Biochemically, the Gαt released by Tas2R activation complexes with AChR and blocks the Gαq cycling of AChR signal transduction. More importantly, a bitter substance, kudinoside A, not only attenuates airway constriction but also significantly inhibits pulmonary inflammation and tissue remodeling in COPD rats, indicating its modulation of additional Gαq-associated pathological processes. Thus, our results suggest that Tas2R activation may be an ideal strategy for halting multiple pathological processes of COPD.
Asunto(s)
Asma , Músculo Liso , Enfermedad Pulmonar Obstructiva Crónica , Receptores Acoplados a Proteínas G , Activación Transcripcional , Animales , Asma/genética , Asma/metabolismo , Asma/fisiopatología , Broncodilatadores/farmacología , Calcio/metabolismo , Músculo Liso/efectos de los fármacos , Músculo Liso/metabolismo , Miocitos del Músculo Liso/efectos de los fármacos , Miocitos del Músculo Liso/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/genética , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Ratas , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Transducción de SeñalRESUMEN
The thymus is the central immune organ, but it is known to progressively degenerate with age. As thymus degeneration is paralleled by the wasting of aging skeletal muscle, we speculated that the thymus may play a role in muscle wasting. Here, using thymectomized mice, we show that the thymus is necessary for skeletal muscle regeneration, a process tightly associated with muscle aging. Compared to control mice, the thymectomized mice displayed comparable growth of muscle mass, but decreased muscle regeneration in response to injury, as evidenced by small and sparse regenerative myofibers along with inhibited expression of regeneration-associated genes myh3, myod, and myogenin. Using paired box 7 (Pax7)-immunofluorescence staining and 5-Bromo-2'-deoxyuridine-incorporation assay, we determined that the decreased regeneration capacity was caused by a limited satellite cell pool. Interestingly, the conditioned culture medium of isolated thymocytes had a potent capacity to directly stimulate satellite cell expansion in vitro. These expanded cells were enriched in subpopulations of quiescent satellite cells (Pax7highMyoDlowEdUpos) and activated satellite cells (Pax7highMyoDhighEdUpos), which were efficiently incorporated into the regenerative myofibers. We thus propose that the thymus plays an essential role in muscle regeneration by directly promoting satellite cell expansion and may function profoundly in the muscle aging process.
Asunto(s)
Músculo Esquelético , Regeneración , Células Satélite del Músculo Esquelético , Timo , Animales , Diferenciación Celular , Proliferación Celular , Ratones , Desarrollo de Músculos/fisiología , Músculo Esquelético/crecimiento & desarrollo , Músculo Esquelético/metabolismo , Proteína MioD/genética , Proteína MioD/metabolismo , Factor de Transcripción PAX7/genética , Factor de Transcripción PAX7/metabolismo , Regeneración/fisiología , Células Satélite del Músculo Esquelético/citología , Células Satélite del Músculo Esquelético/metabolismo , Timo/metabolismo , Cicatrización de HeridasRESUMEN
Heart failure is a leading cause of fatality in Duchenne muscular dystrophy (DMD) patients. Previously, we discovered that cardiac and skeletal-muscle-enriched CIP proteins play important roles in cardiac function. Here, we report that CIP, a striated muscle-specific protein, participates in the regulation of dystrophic cardiomyopathy. Using a mouse model of human DMD, we found that deletion of CIP leads to dilated cardiomyopathy and heart failure in young, non-syndromic mdx mice. Conversely, transgenic overexpression of CIP reduces pathological dystrophic cardiomyopathy in old, syndromic mdx mice. Genome-wide transcriptome analyses reveal that molecular pathways involving fibrogenesis and oxidative stress are affected in CIP-mediated dystrophic cardiomyopathy. Mechanistically, we found that CIP interacts with dystrophin and calcineurin (CnA) to suppress the CnA-Nuclear Factor of Activated T cells (NFAT) pathway, which results in decreased expression of Nox4, a key component of the oxidative stress pathway. Overexpression of Nox4 accelerates the development of dystrophic cardiomyopathy in mdx mice. Our study indicates CIP is a modifier of dystrophic cardiomyopathy and a potential therapeutic target for this devastating disease.
Asunto(s)
Cardiomiopatías , Cardiomiopatía Dilatada , Distrofia Muscular de Duchenne , Animales , Cardiomiopatías/genética , Cardiomiopatías/metabolismo , Cardiomiopatía Dilatada/genética , Proteínas Co-Represoras , Distrofina/metabolismo , Corazón , Humanos , Ratones , Ratones Endogámicos mdx , Distrofia Muscular de Duchenne/patología , Proteínas NuclearesRESUMEN
The appropriate arrangement of myonuclei within skeletal muscle myofibers is of critical importance for normal muscle function, and improper myonuclear localization has been linked to a variety of skeletal muscle diseases, such as centronuclear myopathy and muscular dystrophies. However, the molecules that govern myonuclear positioning remain elusive. Here, we report that skeletal muscle-specific CIP (sk-CIP) is a regulator of nuclear positioning. Genetic deletion of sk-CIP in mice results in misalignment of myonuclei along the myofibers and at specialized structures such as neuromuscular junctions (NMJs) and myotendinous junctions (MTJs) in vivo, impairing myonuclear positioning after muscle regeneration, leading to severe muscle dystrophy in mdx mice, a mouse model of Duchenne muscular dystrophy. sk-CIP is localized to the centrosome in myoblasts and relocates to the outer nuclear envelope in myotubes upon differentiation. Mechanistically, we found that sk-CIP interacts with the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex and the centriole Microtubule Organizing Center (MTOC) proteins to coordinately modulate myonuclear positioning and alignment. These findings indicate that sk-CIP may function as a muscle-specific anchoring protein to regulate nuclear position in multinucleated muscle cells.
Asunto(s)
Proteínas Portadoras/metabolismo , Núcleo Celular/metabolismo , Músculo Esquelético/metabolismo , Mioblastos/metabolismo , Miopatías Estructurales Congénitas/fisiopatología , Proteínas Nucleares/metabolismo , Animales , Proteínas Portadoras/genética , Núcleo Celular/genética , Proteínas Co-Represoras , Humanos , Ratones , Ratones Endogámicos mdx , Ratones Noqueados , Músculo Esquelético/fisiopatología , Miopatías Estructurales Congénitas/genética , Miopatías Estructurales Congénitas/metabolismo , Proteínas Nucleares/genética , Especificidad de ÓrganosRESUMEN
Genetic hearing loss is a common health problem with no effective therapy currently available. DFNA15, caused by mutations of the transcription factor POU4F3, is one of the most common forms of autosomal dominant non-syndromic deafness. In this study, we established a novel mouse model of the human DFNA15 deafness, with a Pou4f3 gene mutation (Pou4f3Δ) identical to that found in a familial case of DFNA15. The Pou4f3(Δ/+) mice suffered progressive deafness in a similar manner to the DFNA15 patients. Hair cells in the Pou4f3(Δ/+) cochlea displayed significant stereociliary and mitochondrial pathologies, with apparent loss of outer hair cells. Progression of hearing and outer hair cell loss of the Pou4f3(Δ/+) mice was significantly modified by other genetic and environmental factors. Using Pou4f3(-/+) heterozygous knockout mice, we also showed that DFNA15 is likely caused by haploinsufficiency of the Pou4f3 gene. Importantly, inhibition of retinoic acid signaling by the aldehyde dehydrogenase (Aldh) and retinoic acid receptor inhibitors promoted Pou4f3 expression in the cochlear tissue and suppressed the progression of hearing loss in the mutant mice. These data demonstrate Pou4f3 haploinsufficiency as the main underlying cause of human DFNA15 deafness and highlight the therapeutic potential of Aldh inhibitors for treatment of progressive hearing loss.
Asunto(s)
Aldehído Deshidrogenasa/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Células Ciliadas Auditivas/patología , Pérdida Auditiva/tratamiento farmacológico , Pérdida Auditiva/etiología , Proteínas de Homeodominio/genética , Factor de Transcripción Brn-3C/genética , Animales , Benzaldehídos/farmacología , Modelos Animales de Enfermedad , Haploinsuficiencia/genética , Pérdida Auditiva/genética , Pérdida Auditiva/patología , Proteínas de Homeodominio/metabolismo , Humanos , Ratones Endogámicos C57BL , Ratones Endogámicos , Ratones Noqueados , Ruido/efectos adversos , Quinolinas/farmacología , Factor de Transcripción Brn-3C/metabolismo , Tretinoina/farmacología , para-Aminobenzoatos/farmacologíaRESUMEN
Tetrandrine is well known to act as a calcium channel blocker. It is a potential candidate for a tumor chemotherapy drug without toxicity. Tetrandrine inhibits cancer cell proliferation and induces cell death through apoptosis and autophagy. As cancer patients usually experience complications with sarcopenia or muscle injury, we thus assessed the effects of tetrandrine on skeletal muscle cells. We report in this study that a low dose of tetrandrine (less than 5 µM) does not affect the proliferation of C2C12 myoblasts, but significantly inhibits myogenic differentiation. Consistently, tetrandrine inhibited muscle regeneration after BaCl2-induced injury. Mechanistic experiments showed that tetrandrine decreased the p-mTOR level and increased the levels of LC3 and SQSTM1/p62 during differentiation. Ad-mRFP-GFP-LC3B transfection experiments revealed that the lysosomal quenching of GFP signals was suppressed by tetrandrine. Furthermore, the levels of DNM1L/Drp1, PPARGA1 and cytochrome C (Cyto C), as well as caspase 3 activation and ROS production, were decreased following tetrandrine administration, indicating that the mitochondrial network signaling was inhibited. Our results indicate that tetrandrine has dual effects on autophagic flux in myoblasts during differentiation, activation in the early stage and blockade in the late stage. The ultimate blocking of autophagic flux by tetrandrine led to the disruption of mitochondria remodeling and inhibition of myogenic differentiation. The inhibitory effects of tetrandrine on skeletal muscle differentiation may limit its application in advanced cancer patients. Thus, great attention should be paid to the clinical use of tetrandrine for cancer therapy.
Asunto(s)
Bencilisoquinolinas , Apoptosis , Autofagia , Bencilisoquinolinas/metabolismo , Bencilisoquinolinas/farmacología , Humanos , Desarrollo de Músculos , Músculo Esquelético/metabolismoRESUMEN
Mutations in the myotubularin 1 (MTM1) gene can cause the fatal disease X-linked centronuclear myopathy (XLCNM), but the underlying mechanism is incompletely understood. In this report, using an Mtm1-/y disease model, we found that expression of the intragenic microRNA miR-199a-1 is up-regulated along with that of its host gene, dynamin 2 (Dnm2), in XLCNM skeletal muscle. To assess the role of miR-199a-1 in XLCNM, we crossed miR-199a-1-/- with Mtm1-/y mice and found that the resultant miR-199a-1-Mtm1 double-knockout mice display markers of improved health, as evidenced by lifespans prolonged by 30% and improved muscle strength and histology. Mechanistic analyses showed that miR-199a-1 directly targets nonmuscle myosin IIA (NM IIA) expression and, hence, inhibits muscle postnatal development as well as muscle maturation. Further analysis revealed that increased expression and phosphorylation of signal transducer and activator of transcription 3 (STAT3) up-regulates Dnm2/miR-199a-1 expression in XLCNM muscle. Our results suggest that miR-199a-1 has a critical role in XLCNM pathology and imply that this microRNA could be targeted in therapies to manage XLCNM.
Asunto(s)
Dinamina II/genética , MicroARNs/genética , Miopatías Estructurales Congénitas/genética , Animales , Sistemas CRISPR-Cas , Dinamina II/análisis , Femenino , Longevidad , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , MicroARNs/análisis , Fuerza Muscular , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Miopatías Estructurales Congénitas/patologíaRESUMEN
Leucocyte adhesion to the vascular endothelium is a critical event in the early inflammatory response to infection and injury. This process is primarily regulated by the expression of cell adhesion molecules (CAMs) in endothelial cells. It has been well documented that tumor necrosis factor alpha (TNF-α) is a key regulator of CAM expression within this process, but its regulatory mechanism remains controversial. To investigate the scenario within this process, we assessed the role of zipper-interacting protein kinase (ZIPK), a serine/threonine kinase with multiple substrates, in CAM expression. We used TNF-α as inflammatory stimulator and found that ZIPK was integrated into the signaling regulation of TNF-α-mediated CAM expression. In human umbilical vein endothelial cells (HUVECs), TNF-α exposure led to significantly increased expression of both intercellular CAM-1 (ICAM-1) and vascular CAM-1 (VCAM-1), along with an increase in the adhesion of THP-1 monocytes to HUVECs. Simultaneously, ZIPK gene was also up-regulated at the transcription level. These effects were clearly inhibited by the ZIPK-specific inhibitor Tc-DAPK6 or small interfering RNA (siRNA) capable of specifically inhibiting ZIPK expression. We thus suggest that both ZIPK activation and ZIPK gene expression are necessary for TNF-α-mediated CAM expression and leucocyte adhesion. Interestingly, ZIPK inhibition also significantly suppressed TNF-α-induced nuclear factor kappa B (NF-κB) activation, indicating that TNF-α-mediated ZIPK expression functions upstream of NF-κB and CAM expression. We thus propose a TNF-α/ZIPK/NF-κB signaling axis for CAM expression that is necessary for leucocyte adhesion to endothelial cells. Our data in this study revealed a potential molecular target for exploring anti-inflammation drugs.
Asunto(s)
Proteínas Quinasas Asociadas a Muerte Celular/biosíntesis , Molécula 1 de Adhesión Intercelular/metabolismo , Leucocitos/metabolismo , Transducción de Señal/efectos de los fármacos , Factor de Necrosis Tumoral alfa/farmacología , Molécula 1 de Adhesión Celular Vascular/metabolismo , Adhesión Celular/efectos de los fármacos , Proteínas Quinasas Asociadas a Muerte Celular/genética , Células Endoteliales de la Vena Umbilical Humana , Humanos , Molécula 1 de Adhesión Intercelular/genética , Transducción de Señal/genética , Células THP-1 , Molécula 1 de Adhesión Celular Vascular/genéticaRESUMEN
The paracellular gap formed by endothelial cell (EC) contraction is fundamental for endothelium permeability, but the mechanism underlying EC contraction has yet to be determined. Here, we identified the zipper-interacting protein kinase (ZIPK) as the kinase for EC contraction and myosin light chain (MLC) phosphorylation. Inhibition of ZIPK activity by pharmacological inhibitors and small interfering RNAs led to a significant decrease in the mono- and diphosphorylation of MLCs along with a contractile response to thrombin, suggesting an essential role of ZIPK in EC paracellular permeability. To assess the role of ZIPK in vivo, we established mouse lines with conditional deletion of Zipk gene. The endothelium-specific deletion of Zipk led to embryonic lethality, whereas the UBC-CreERT2-mediated deletion of Zipk by tamoxifen induction at adulthood caused no apparent phenotype. The induced deletion of Zipk significantly inhibited ischemia-reperfusion-induced blood-brain barrier dysfunction and neuronal injuries from middle cerebral artery occlusion and reperfusion, as evidenced by reduced infarct and edema volume, attenuated Evans blue dye leakage, and improved neuronal behavior. We thus concluded that ZIPK and its phosphorylation of MLC were required for EC contraction and ischemic neuronal injuries. ZIPK may be a prospective therapeutic target for stroke.-Zhang, Y., Zhang, C., Zhang, H., Zeng, W., Li, S., Chen, C., Song, X., Sun, J., Sun, Z., Cui, C., Cao, X., Zheng, L., Wang, P., Zhao, W., Zhang, Z., Xu, Y., Zhu, M., Chen, H. ZIPK mediates endothelial cell contraction through myosin light chain phosphorylation and is required for ischemic-reperfusion injury.
Asunto(s)
Proteínas Quinasas Asociadas a Muerte Celular/metabolismo , Células Endoteliales/metabolismo , Cadenas Ligeras de Miosina/metabolismo , Daño por Reperfusión/metabolismo , Animales , Barrera Hematoencefálica/metabolismo , Permeabilidad Capilar , Línea Celular , Proteínas Quinasas Asociadas a Muerte Celular/deficiencia , Proteínas Quinasas Asociadas a Muerte Celular/genética , Células Endoteliales/citología , Femenino , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fenotipo , Fosforilación , Embarazo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Daño por Reperfusión/genética , Daño por Reperfusión/patologíaRESUMEN
BACKGROUND: Allergic inflammation has long been implicated in asthmatic hyperresponsiveness of airway smooth muscle (ASM), but its underlying mechanism remains incompletely understood. Serving as G protein-coupled receptor agonists, several inflammatory mediators can induce membrane depolarization, contract ASM, and augment cholinergic contractile response. We hypothesized that the signal cascade integrating on membrane depolarization by the mediators might involve asthmatic hyperresponsiveness. OBJECTIVE: We sought to investigate the signaling transduction of inflammatory mediators in ASM contraction and assess its contribution in the genesis of hyperresponsiveness. METHODS: We assessed the capacity of inflammatory mediators to induce depolarization currents by electrophysiological analysis. We analyzed the phenotypes of transmembrane protein 16A (TMEM16A) knockout mice, applied pharmacological reagents, and measured the Ca2+ signal during ASM contraction. To study the role of the depolarization signaling in asthmatic hyperresponsiveness, we measured the synergistic contraction by methacholine and inflammatory mediators both ex vivo and in an ovalbumin-induced mouse model. RESULTS: Inflammatory mediators, such as 5-hydroxytryptamin, histamine, U46619, and leukotriene D4, are capable of inducing Ca2+-activated Cl- currents in ASM cells, and these currents are mediated by TMEM16A. A combination of multiple analysis revealed that a G protein-coupled receptor-TMEM16A-voltage-dependent Ca2+ channel signaling axis was required for ASM contraction induced by inflammatory mediators. Block of TMEM16A activity may significantly inhibit the synergistic contraction of acetylcholine and the mediators and hence reduces hypersensitivity. CONCLUSIONS: A G protein-coupled receptor-TMEM16A-voltage-dependent Ca2+ channel axis contributes to inflammatory mediator-induced ASM contraction and synergistically activated TMEM16A by allergic inflammatory mediators with cholinergic stimuli.
Asunto(s)
Anoctamina-1/metabolismo , Asma/metabolismo , Hiperreactividad Bronquial/metabolismo , Canales de Calcio/metabolismo , Contracción Muscular , Músculo Liso/fisiopatología , Transducción de Señal , Animales , Asma/fisiopatología , Biomarcadores/metabolismo , Hiperreactividad Bronquial/fisiopatología , Fenómenos Electrofisiológicos , Femenino , Cobayas , Masculino , Ratones , Ratones Noqueados , FenotipoRESUMEN
Inheritance of the callipyge phenotype in sheep is an example of polar overdominance inheritance, an unusual mode of inheritance. To investigate the underlying molecular mechanism, we profiled the expression of the genes located in the Delta-like 1 homolog (Dlk1)-type III iodothyronine deiodinase (Dio3) imprinting region in mice. We found that the transcripts of the microRNA (miR) 379/miR-544 cluster were highly expressed in neonatal muscle and paralleled the expression of the Dlk1. We then determined the in vivo role of the miR-379/miR-544 cluster by establishing a mouse line in which the cluster was ablated. The maternal heterozygotes of young mutant mice displayed a hypertrophic tibialis anterior muscle, extensor digitorum longus muscle, gastrocnemius muscle, and gluteus maximus muscle and elevated expression of the DLK1 protein. Reduced expression of DLK1 was mediated by miR-329, a member of this cluster. Our results suggest that maternal expression of the imprinted miR-379/miR-544 cluster regulates paternal expression of the Dlk1 gene in mice. We therefore propose a miR-based molecular working model for polar overdominance inheritance.
Asunto(s)
Impresión Genómica , Péptidos y Proteínas de Señalización Intercelular/genética , MicroARNs/genética , Animales , Proteínas de Unión al Calcio , Femenino , Ratones , Familia de MultigenesRESUMEN
BACKGROUND We desired to observe the changes of transforming growth factor-ß1/drosophila mothers against decapentaplegic protein (TGF-ß1/Smad3) signaling pathway in the hippocampus region of cerebral ischemic stroke rats so that the effects of this pathway on nerve cells can be investigated. MATERIAL AND METHODS The ischemic stroke models were built by middle cerebral artery occlusion (MCAO) in vivo and oxygen-glucose deprivation (OGD) in vitro. TGF-ß1 and TGF-ß1 inhibitors were injected into rat models while TGF-ß1, TGF-ß1 siRNA, Smad3, and Smad3 siRNA were transfected into cells. Infarct sizes were measured using triphenyltetrazolium chloride (TTC) staining, while the apoptosis rate of cells were calculated by Annexin V-fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI) staining. Levels of TGF-ß1, Smad3, and Bcl-2 were examined by real-time polymerase chain reaction (RT-PCR), immunohistochemical, and Western blot analysis. RESULTS The expressions of TGF-ß1/Smad3 signal pathway were significantly increased in both model rats and BV2 cells, whereas the expression of Bcl-2 was down-regulated (P<0.05). The TGF-ß1/Smad3 signal pathway exhibited protective effects, including the down-regulation of infarction size in cerebral tissues and the down-regulation of apoptosis rate of BV2 cells by increasing the expression of Bcl-2 (P<0.05). In addition, these effects could be antagonized by the corresponding inhibitors and siRNA (P<0.05). CONCLUSIONS The TGF-ß1/Smad3 signaling pathway was up-regulated once cerebral ischemic stroke was simulated. TGF-ß1 may activate the expression of Bcl-2 via Smad3 to suppress the apoptosis of neurons.
Asunto(s)
Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Proteína smad3/metabolismo , Accidente Cerebrovascular/metabolismo , Accidente Cerebrovascular/patología , Factor de Crecimiento Transformador beta1/metabolismo , Animales , Apoptosis/fisiología , Isquemia Encefálica/genética , Regulación hacia Abajo , Infarto de la Arteria Cerebral Media/metabolismo , Masculino , Neuronas/metabolismo , Neuronas/patología , ARN Mensajero/metabolismo , ARN Interferente Pequeño/administración & dosificación , ARN Interferente Pequeño/genética , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Reacción en Cadena en Tiempo Real de la Polimerasa , Transducción de Señal , Proteína smad3/genética , Accidente Cerebrovascular/genética , Factor de Crecimiento Transformador beta1/genéticaRESUMEN
Myosin light chain kinase (MLCK) has long been implicated in the myosin phosphorylation and force generation required for cell migration. Here, we surprisingly found that the deletion of MLCK resulted in fast cell migration, enhanced protrusion formation, and no alteration of myosin light chain phosphorylation. The mutant cells showed reduced membrane tether force and fewer membrane F-actin filaments. This phenotype was rescued by either kinase-dead MLCK or five-DFRXXL motif, a MLCK fragment with potent F-actin-binding activity. Pull-down and co-immunoprecipitation assays showed that the absence of MLCK led to attenuated formation of transmembrane complexes, including myosin II, integrins and fibronectin. We suggest that MLCK is not required for myosin phosphorylation in a migrating cell. A critical role of MLCK in cell migration involves regulating the cell membrane tension and protrusion necessary for migration, thereby stabilizing the membrane skeleton through F-actin-binding activity. This finding sheds light on a novel regulatory mechanism of protrusion during cell migration.
Asunto(s)
Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Membrana Celular/metabolismo , Yeyuno/metabolismo , Miocitos del Músculo Liso/metabolismo , Quinasa de Cadena Ligera de Miosina/metabolismo , Citoesqueleto de Actina/química , Actinas/química , Actinas/genética , Adenoviridae/genética , Secuencias de Aminoácidos , Animales , Membrana Celular/química , Movimiento Celular , Regulación de la Expresión Génica , Vectores Genéticos , Yeyuno/citología , Ratones , Ratones Noqueados , Datos de Secuencia Molecular , Miocitos del Músculo Liso/citología , Quinasa de Cadena Ligera de Miosina/química , Quinasa de Cadena Ligera de Miosina/genética , Fosforilación , Cultivo Primario de Células , Unión Proteica , Transducción de Señal , Tensión Superficial , TransfecciónRESUMEN
To reveal complex causes of aircraft events, this paper aims to mine association rules between the trigger probability and relative strength via a modified Apriori algorithm. Clustering is adopted for data preprocessing and TF-IDF value calculation. Causative item sets of aircraft events are obtained based on the accident causation 2-4 model and are coded to establish code indicators. By avoiding the use of statistical methodologies to resolve not-a-number (NaN) values for altering the interrelations among causes, an enhancement in the Apriori algorithm is proposed by considering frequent items. By extracting frequent patterns, in this paper, all the association rules that satisfy three perspectives (support, confidence and lift) are determined by constantly generating and pruning candidate item sets. A network graph is used to visualize the association rules between different unsafe events and all types of causes. Finally, 9835 representative pieces of data, including general unsafe events, general incidents and serious incidents from the Southwest Air Traffic Management Bureau, are selected for analysis. The results show that improper energy allocation, poor conflict resolution ability, inadequate onsite management duties, adoption of a luck mentality, and occurrence of controller oversight are highly correlated with general unsafe events, and failure to rectify incorrect recitation is notably correlated with general incidents, while inadequate manual promotion, lack of conflict judgement and insufficient safety management are strongly correlated with serious incidents. This study quantitatively reveals the potential patterns and characteristics of mutual interactions among various types of historical aircraft events and highlights directions for controllable prevention and prediction of aircraft events.
RESUMEN
Avicennia marina (Forssk.) Vierh. is a highly salt-tolerant mangrove, and its fruit has been traditionally used for treating constipation and dysentery. In this study, a pectin (AMFPs-0-1) was extracted and isolated from this fruit for the first time, its structure was analyzed, and the effects on the human gut microbiota were investigated. The results indicated that AMFPs-0-1 with a molecular weight of 798 kDa had a backbone consisting of alternating â2)-α-L-Rhap-(1â and â4)-α-D-GalpA-(1â residues and side chains composed of â3-α-L-Araf-(1â-linked arabinan with a terminal ß-L-Araf, â5-α-L-Araf-(1â-linked arabinan, and â4)-ß-D-Galp-(1â-linked galactan that linked to the C-4 positions of all α-L-Rhap residues in the backbone. It belongs to a type I rhamnogalacturonan (RG-I) pectin but has no arabinogalactosyl chains. AMFPs-0-1 could be consumed by human gut microbiota and increase the abundance of some beneficial bacteria, such as Bifidobacterium, Mitsuokella, and Megasphaera, which could help fight digestive disorders. These findings provide a structural basis for the potential application of A. marina fruit RG-I pectic polysaccharides in improving human intestinal health.
Asunto(s)
Avicennia , Fermentación , Frutas , Microbioma Gastrointestinal , Pectinas , Prebióticos , Pectinas/química , Frutas/química , Avicennia/química , Avicennia/microbiología , Humanos , Microbioma Gastrointestinal/efectos de los fármacos , Peso MolecularRESUMEN
Myocardin belongs to the SAF-A/B, Acinus, PIAS (SAP) domain family of transcription factors and is specifically expressed in cardiac and smooth muscle. Myocardin functions as a transcriptional coactivator of SRF and is sufficient and necessary for smooth muscle gene expression. We have previously found that myocardin induces the acetylation of nucleosomal histones surrounding SRF-binding sites in the control regions of cardiac and smooth muscle genes through recruiting chromatin-modifying enzyme p300, yet no studies have determined whether myocardin itself is similarly modified. In this study, we show that myocardin is a direct target for p300-mediated acetylation. p300 acetylates lysine residues at the N terminus of the myocardin protein. Interestingly, a direct interaction between p300 and myocardin, which is mediated by the C terminus of myocardin, is required for the acetylation event. Acetylation of myocardin by p300 enhances the association of myocardin and SRF as well as the formation of the myocardin-SRF-CArG box ternary complex. Conversely, acetylation of myocardin decreases the binding of histone deacetylase 5 (HDAC5) to myocardin. Acetylation of myocardin is required for myocardin to activate smooth muscle genes. Our study demonstrates that acetylation plays a key role in modulating myocardin function in controlling cardiac and smooth muscle gene expression.
Asunto(s)
Músculo Liso/metabolismo , Miocardio/metabolismo , Proteínas Nucleares/metabolismo , Transactivadores/metabolismo , Acetilación , Animales , Células COS , Cromatina/metabolismo , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Histonas/genética , Ratones , Modelos Biológicos , Factor de Respuesta Sérica/metabolismo , Transducción de Señal , Activación Transcripcional , Factores de Transcripción p300-CBP/metabolismoRESUMEN
MicroRNAs (miRNAs) are a class of small non-coding RNAs that repress the expression of their target genes post-transcriptionally. MiRNAs participate in the regulation of a variety of biological processes, including development and diseases. However, the functional role and molecular mechanism by which miRNAs regulate skeletal muscle development and differentiation are not fully understood. In this report, we identified miR-23a as a key regulator of skeletal muscle differentiation. Using bioinformatics analyses, miR-23a is predicted to target multiple adult fast myosin heavy chain (Myh) genes, including Myh 1, 2 and 4. Luciferase reporter assays show that miR-23a directly targets the 3' untranslated regions (UTRs) of these mRNAs. Interestingly, the expression level of mature miR-23a is inversely correlated with myogenic progression in mouse skeletal muscle. Both gain- and loss-of-function studies using C2C12 myoblasts demonstrate that miR-23a inhibits myogenic differentiation. These findings therefore reveal a novel role of miR-23a in regulating myogenic differentiation via inhibiting the expression of fast myosin heavy chain isoforms.
Asunto(s)
Regulación hacia Abajo , MicroARNs/genética , Músculo Esquelético/citología , Mioblastos/citología , Cadenas Pesadas de Miosina/genética , Animales , Diferenciación Celular , Línea Celular , Células Cultivadas , Humanos , Ratones , MicroARNs/metabolismo , Mioblastos/metabolismo , Cadenas Pesadas de Miosina/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismoRESUMEN
The location of Low-Altitude Flight Service Station (LAFSS) is a comprehensive decision work, and it is also a multi-objective optimization problem (MOOP) with constraints. As a swarm intelligence search algorithm for solving constrained MOOP, the Immune Algorithm (IA) retains the excellent characteristics of genetic algorithm. Using some characteristic information or knowledge of the problem selectively and purposefully, the degradation phenomenon in the optimization process can be suppressed and the global optimum can be achieved. However, due to the large range involved in the low-altitude transition flight, the geographical characteristics, economic level and service requirements among the candidate stations in the corridor are quite different, and the operational safety and service efficiency are interrelated and conflict with each other. And all objectives cannot be optimal. Therefore, this article proposes a Modified Immune Algorithm (MIA) with two-layer response to solve the constrained multi-objective location mathematical model of LAFSS. The first layer uses the demand track as the cell membrane positioning pattern recognition service response distance to trigger the innate immunity to achieve the basic requirements of security service coverage. In the second layer, the expansion and upgrading of adjacent candidate sites are compared to the pathogen's effector, and the adaptive immunity is directly or indirectly triggered again through the cloning, mutation and reproduction between candidate sites to realize the multi-objective equilibrium of the scheme. Taking 486,000 km2 of Sichuan Province as an example, MIA for LAFSS is simulated by the MATLAB platform. Based on the Spring open source application framework of Java platform, the cesiumjs map data is called through easyui, and the visualization of site selection scheme is presented with the terrain data of Map World as the background. The experimental results show that, compared with dynamic programming and ordinary immunization, the immune trigger mode of double response and the improved algorithm of operation parameter combination designed by the Taguchi experiment, the total economic cost of location selection is reduced by 26.4%, the service response time is reduced by 25%, the repeat coverage rate is reduced by 29.5% and the effective service area is increased by 17.5%. The security risk, service efficiency and location cost are balanced. The present work is to provide an effective location method for the layout number and location of local transfer flight service stations. For complex scenes with larger scale of low-altitude flight supply and demand and larger terrain changes in the region, the above research methods can be used to effectively split and reduce the dimension.
RESUMEN
BACKGROUND: Chronic subdural hematomas (CSDHs) are one of the most common neurosurgical conditions. The standard surgical technique includes burr-hole craniostomy, followed by intraoperative irrigation and placement of subdural closed-system drainage. The drainage is generally removed after 48 h, which can be described as fixed-time drainage strategy. According to literature, the recurrence rate is 5-33% with this strategy. In our retrospective study, postoperative hematoma volume was found to significantly increase the risk of recurrence. Based on these results, an exhaustive drainage strategy is conducted to minimize postoperative hematoma volume and achieve a low recurrence rate and good outcomes. METHODS: This is a prospective, multicenter, open-label, blinded endpoint randomized controlled trial designed to include 304 participants over the age of 18-90 years presenting with a symptomatic CSDH verified on cranial computed tomography or magnetic resonance imaging. Participants will be randomly allocated to perform exhaustive drainage (treatment group) or fixed-time drainage (control group) after a one-burr hole craniostomy. The primary endpoint will be recurrence indicating a reoperation within 6 months. DISCUSSION: This study will validate the effect and safety of exhaustive drainage after one-burr hole craniostomy in reducing recurrence rates and provide critical information to improve CSDH surgical management. TRIAL REGISTRATION: Clinicaltrials.gov, NCT04573387. Registered on October 5, 2020.