Transcriptomic and Epigenetic Regulation of Disuse Atrophy and the Return to Activity in Skeletal Muscle

Physical inactivity and disuse are major contributors to age-related muscle loss. Denervation of skeletal muscle has been previously used as a model with which to investigate muscle atrophy following disuse. Although gene regulatory networks that control skeletal muscle atrophy after denervation have been established, the transcriptome in response to the recovery of muscle after disuse and the associated epigenetic mechanisms that may function to modulate gene expression during skeletal muscle atrophy or recovery have yet to be investigated. We report that silencing the tibialis anterior muscle in rats with tetrodotoxin (TTX)—administered to the common peroneal nerve—resulted in reductions in muscle mass of 7, 29, and 51% with corresponding reductions in muscle fiber cross-sectional area of 18, 42, and 69% after 3, 7, and 14 d of TTX, respectively. Of importance, 7 d of recovery, during which rodents resumed habitual physical activity, restored muscle mass from a reduction of 51% after 14 d TTX to a reduction of only 24% compared with sham control. Returning muscle mass to levels observed at 7 d TTX administration (29% reduction). Transcriptome-wide analysis demonstrated that 3714 genes were differentially expressed across all conditions at a significance of P ≤ 0.001 after disuse-induced atrophy. Of interest, after 7 d of recovery, the expression of genes that were most changed during TTX had returned to that of the sham control. The 20 most differentially expressed genes after microarray analysis were identified across all conditions and were cross-referenced with the most frequently occurring differentially expressed genes between conditions. This gene subset included myogenin (MyoG), Hdac4, Ampd3, Trim63 (MuRF1), and acetylcholine receptor subunit α1 (Chrna1). Transcript expression of these genes and Fboxo32 (MAFbx), because of its previously identified role in disuse atrophy together with Trim63 (MuRF1), were confirmed by real-time quantitative RT-PCR, and DNA methylation of their promoter regions was analyzed by PCR and pyrosequencing. MyoG, Trim63 (MuRF1), Fbxo32 (MAFbx), and Chrna1 demonstrated significantly decreased DNA methylation at key time points after disuse-induced atrophy that corresponded with significantly increased gene expression. Of importance, after TTX cessation and 7 d of recovery, there was a marked increase in the DNA methylation profiles of Trim63 (MuRF1) and Chrna1 back to control levels. This also corresponded with the return of gene expression in the recovery group back to baseline expression observed in sham-operated controls. To our knowledge, this is the first study to demonstrate that skeletal muscle atrophy in response to disuse is accompanied by dynamic epigenetic modifications that are associated with alterations in gene expression, and that these epigenetic modifications and gene expression profiles are reversible after skeletal muscle returns to normal activity

Muscle wasting and the temporal gene expression pattern in a novel rat intensive care unit model

<p>Abstract</p> <p>Background</p> <p>Acute quadriplegic myopathy (AQM) or critical illness myopathy (CIM) is frequently observed in intensive care unit (ICU) patients. To elucidate duration-dependent effects of the ICU intervention on molecular and functional networks that control the muscle wasting and weakness associated with AQM, a gene expression profile was analyzed at time points varying from 6 hours to 14 days in a unique experimental rat model mimicking ICU conditions, i.e., post-synaptically paralyzed, mechanically ventilated and extensively monitored animals.</p> <p>Results</p> <p>During the observation period, 1583 genes were significantly up- or down-regulated by factors of two or greater. A significant temporal gene expression pattern was constructed at short (6 h-4 days), intermediate (5-8 days) and long (9-14 days) durations. A striking early and maintained up-regulation (6 h-14d) of muscle atrogenes (muscle ring-finger 1/tripartite motif-containing 63 and F-box protein 32/atrogin-1) was observed, followed by an up-regulation of the proteolytic systems at intermediate and long durations (5-14d). Oxidative stress response genes and genes that take part in amino acid catabolism, cell cycle arrest, apoptosis, muscle development, and protein synthesis together with myogenic factors were significantly up-regulated from 5 to 14 days. At 9-14 d, genes involved in immune response and the caspase cascade were up-regulated. At 5-14d, genes related to contractile (myosin heavy chain and myosin binding protein C), regulatory (troponin, tropomyosin), developmental, caveolin-3, extracellular matrix, glycolysis/gluconeogenesis, cytoskeleton/sarcomere regulation and mitochondrial proteins were down-regulated. An activation of genes related to muscle growth and new muscle fiber formation (increase of myogenic factors and JunB and down-regulation of myostatin) and up-regulation of genes that code protein synthesis and translation factors were found from 5 to 14 days.</p> <p>Conclusions</p> <p>Novel temporal patterns of gene expression have been uncovered, suggesting a unique, coordinated and highly complex mechanism underlying the muscle wasting associated with AQM in ICU patients and providing new target genes and avenues for intervention studies.</p

Diaphragm Muscle Weakness in an Experimental Porcine Intensive Care Unit Model

In critically ill patients, mechanisms underlying diaphragm muscle remodeling and resultant dysfunction contributing to weaning failure remain unclear. Ventilator-induced modifications as well as sepsis and administration of pharmacological agents such as corticosteroids and neuromuscular blocking agents may be involved. Thus, the objective of the present study was to examine how sepsis, systemic corticosteroid treatment (CS) and neuromuscular blocking agent administration (NMBA) aggravate ventilator-related diaphragm cell and molecular dysfunction in the intensive care unit. Piglets were exposed to different combinations of mechanical ventilation and sedation, endotoxin-induced sepsis, CS and NMBA for five days and compared with sham-operated control animals. On day 5, diaphragm muscle fibre structure (myosin heavy chain isoform proportion, cross-sectional area and contractile protein content) did not differ from controls in any of the mechanically ventilated animals. However, a decrease in single fibre maximal force normalized to cross-sectional area (specific force) was observed in all experimental piglets. Therefore, exposure to mechanical ventilation and sedation for five days has a key negative impact on diaphragm contractile function despite a preservation of muscle structure. Post-translational modifications of contractile proteins are forwarded as one probable underlying mechanism. Unexpectedly, sepsis, CS or NMBA have no significant additive effects, suggesting that mechanical ventilation and sedation are the triggering factors leading to diaphragm weakness in the intensive care unit

Objetivos de desarrollo sostenible y Derechos Humanos: paz, justicia e instituciones sólidas / Derechos Humanos y empresas

Nota previa / Cástor Miguel Díaz Barrado (pp. 7-9). -- Unión Europea: Derechos Humanos y desarrollo sostenible / Araceli Mangas Martín (pp. 13 - 26). -- Paz, seguridad y gobernanza: el ODS 16 y la Agenda 2030 de desarrollo sostenible / José Antonio Sanahuja (pp. 27 - 54). -- La aplicación extraterritorial de los Derechos Humanos por acciones de empresas / Pablo Antonio Fernández Sánchez (pp. 57 - 60). -- Hacia un futuro tratado internacional sobre las empresas y los Derechos Humanos / Eugenia López-Jacoiste (pp. 61 - 73). -- La importancia del enfoque de los Derechos Humanos en los objetivos de desarrollo del sostenible / Diana M. Verdiales López (pp. 75 - 90). -- La perspectiva de género en la resolución de conflictos armados: las mujeres como agentes de paz / Cristina del Prado Higuera (pp. 93 - 106). -- La mutilación genital femenina desde una perspectiva integral y multidisciplinar / Cristina Hermida del Llano (pp. 107 - 120). -- Poner fin al maltrato, la explotación, la trata y todas las formas de violencia y tortura contra los niños: la trata de niños / María Ángeles Cano Linares (pp. 123 - 136). -- Participación juvenil en el fortalecimiento de las instituciones y el establecimiento de la paz: programas de participación juvenil del sistema de Naciones Unidas / Enrique Hernández Díez (pp. 137 - 160). -- Estado de la violencia criminal en la sociedad internacional: respuestas de la comunidad internacional para avanzar hacia el objetivo 16, Agenda 2030 / Sagrario Morán Blanco (pp. 163 - 178). -- Fortalecer la recuperación y devolución de bienes robados: justicia y reparación del daño causado a las víctimas y la sociedad como metas del objetivo 16 de los objetivos de desarrollo sostenible / Francisco Jiménez García (pp. 179 - 192). -- El derecho internacional, los ODS y la lucha contra el crimen transnacional / Juan Manuel Rodríguez Barrigón (pp. 193 - 216). -- El derecho internacional frente a la criminalidad financiera transnacional: la prevención y sanción del blanqueo de capitales / Jorge Urbaneja Cillán (pp. 217 - 232). -- Acceso a la justicia y objetivos del desarrollo sostenible / Florabel Quispe Remón (pp. 235 - 248). -- Paz y objetivos de desarrollo sostenible: la contribución del objetivo 16 / Elena C. Díaz Galán (pp. 249 - 262). -- Seguridad sanitaria y empresas / Ana Cristina Gallego Hernández (pp. 265 - 272). -- El acaparamiento de tierras por empresas multinacionales y la seguridad alimentaria / Adriana Fillol Mazo (pp. 273 - 288). -- Importancia y características de los planes nacionales de empresas y Derechos Humanos en relación con el desarrollo sostenible / Alberto Jiménez-Piernas García (pp. 289 - 301). -- Objetivo de desarrollo sostenible 16. Principios rectores y espacio iberoamericano: el caso Berta Cáceres / Ana Manero Salvador (pp. 305 - 315). -- Derechos de los pueblos indígenas: marcos de protección en la Agenda 2030 y en los principios rectores sobre empresas y Derechos Humanos / Juan Daniel Oliva Martínez y Adriana Sánchez Lizama (pp. 317 - 331

Oxysterol-induced soluble endoglin release and its involvement in hypertension

[EN]Ischemia in the placenta is considered the base of the pathogenesis of preeclampsia, a pregnancy-specific syndrome in which soluble endoglin (sEng) is a prognostic marker and plays a pathogenic role. Here, we investigated the effects of hypoxia and the downstream pathways in the release of sEng. Under hypoxic conditions, the trophoblast-like cell line JAR showed an increase in sEng parallel to an elevated formation of reactive oxygen species. Because reactive oxygen species are related to the formation of oxysterols, we assessed the effect of 22-(R)-hydroxycholesterol, a natural ligand of the liver X receptor (LXR), and the LXR synthetic agonist T0901317. Treatment of JAR cells or human placental explants with 22-(R)-hydroxycholesterol or T0901317 resulted in a clear increase in sEng that was dependent on LXR. These LXR agonists induced an increased matrix metalloproteinase-14 expression and activity and a significant reduction of its endogenous inhibitor, tissue inhibitor of metalloproteinase-3. In addition, mice treated with LXR agonists underwent an increase in the plasma sEng levels, concomitant with an increase in arterial pressure. Moreover, transgenic mice overexpressing sEng displayed high blood pressure. Finally, administration of an endoglin peptide containing the consensus matrix metalloproteinase-14 cleavage site G-L prevented the oxysterol-dependent increase in arterial pressure and sEng levels in mice. These studies provide a clue to the involvement of the LXR pathway in sEng release and its pathogenic role in vascular disorders such as preeclampsia.Ministerio de Ciencia e Innovación; Genoma España (MEICA); Instituto Reina Sofía de Investigación Nefrológica (FRIAT); Junta de Castilla and León; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Red de Investigación Cooperativa en Enfermedades Renales (REDINREN