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Over the last years, the use of peripheral blood-derived big datasets in combination with machine learning technology has accelerated the understanding, prediction, and management of pulmonary and critical care conditions. The goal of this article is to provide readers with an introduction to the methods and applications of blood omics and other multiplex-based technologies in the pulmonary and critical care medicine setting to better appreciate the current literature in the field. To accomplish that, we provide essential concepts needed to rationalize this approach and introduce readers to the types of molecules that can be obtained from the circulating blood to generate big datasets; elaborate on the differences between bulk, sorted, and single-cell approaches; and the basic analytical pipelines required for clinical interpretation. Examples of peripheral blood-derived big datasets used in recent literature are presented, and limitations of that technology are highlighted to qualify both the current and future value of these methodologies.
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Cuidados Críticos , Aprendizaje Automático , Humanos , PredicciónRESUMEN
Patients with chronic obstructive pulmonary disease (COPD)-pulmonary emphysema often develop locomotor muscle dysfunction, which entails reduced muscle mass and force-generation capacity and is associated with worse outcomes, including higher mortality. Myogenesis contributes to adult muscle integrity during injury-repair cycles. Injurious events crucially occur in the skeletal muscles of patients with COPD in the setting of exacerbations and infections, which lead to acute decompensations for limited periods of time, after which patients typically fail to recover the baseline status they had before the acute event. Autophagy, which is dysregulated in muscles from patients with COPD, is a key regulator of muscle stem-satellite- cells activation and myogenesis, yet very little research has so far mechanistically investigated the role of autophagy dysregulation in COPD muscles. Using a genetically inducible interleukin-13-driven pulmonary emphysema model leading to muscle dysfunction, and confirmed with a second genetic animal model, we found a significant myogenic dysfunction associated with the reduced proliferative capacity of satellite cells. Transplantation experiments followed by lineage tracing suggest that an intrinsic defect in satellite cells, and not in the COPD environment, plays a dominant role in the observed myogenic dysfunction. RNA sequencing analysis and direct observation of COPD mice satellite cells suggest dysregulated autophagy. Moreover, while autophagy flux experiments with bafilomycin demonstrated deacceleration of autophagosome turnover in COPD mice satellite cells, spermidine-induced autophagy stimulation leads to a higher replication rate and myogenesis in these animals. Our data suggest that pulmonary emphysema causes disrupted myogenesis, which could be improved with stimulation of autophagy and satellite cells activation, leading to an attenuated muscle dysfunction.
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Enfermedad Pulmonar Obstructiva Crónica , Enfisema Pulmonar , Animales , Autofagia , Humanos , Ratones , Desarrollo de Músculos , Músculo Esquelético , Enfisema Pulmonar/etiologíaRESUMEN
Locomotor skeletal muscle dysfunction is a relevant comorbidity of chronic obstructive pulmonary disease (COPD) and is strongly associated with worse clinical outcomes including higher mortality. Over the last decades, a large body of literature helped characterize the process, defining the disruptive muscle phenotype caused by COPD that involves reduction in muscle mass, force-generation capacity, fatigue-tolerance, and regenerative potential following injury. A major limitation in the field has been the scarcity of well-calibrated animal models to conduct mechanistic research based on loss- and gain-of-function studies. This article provides an overall description of the process, the tools available to mechanistically investigate it, and the potential role of mitochondrially driven metabolic signals on the regulation muscle regeneration after injury in COPD. Finally, a description of future avenues to further expand on the area is proposed based on very recent evidence involving mitochondrial metabolic cues affecting myogenesis.
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Enfermedades Musculares , Enfermedad Pulmonar Obstructiva Crónica , Animales , Músculo Esquelético/metabolismo , Enfermedades Musculares/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/metabolismoRESUMEN
Patients with pulmonary emphysema often develop locomotor muscle dysfunction, which is independently associated with disability and higher mortality in that population. Muscle dysfunction entails reduced force generation capacity, which partially depends on fibers' oxidative potential, yet very little mechanistic research has focused on muscle respiration in pulmonary emphysema. Using a recently established animal model of pulmonary emphysema-driven skeletal muscle dysfunction, we found downregulation of SDHC (succinate dehydrogenase subunit C) in association with lower oxygen consumption and fatigue tolerance in locomotor muscles. Reduced SDH activity has been previously observed in muscles from patients with pulmonary emphysema, and we found that SDHC is required to support respiration in cultured muscle cells. Moreover, in vivo gain of SDH function in emphysema animals' muscles resulted in better oxygen consumption rate and fatigue tolerance. These changes correlated with a larger number of relatively more oxidative type 2-A and 2X fibers and a reduced amount of 2B fibers. Our data suggest that SDHC is a key regulator of respiration and fatigability in pulmonary emphysema-driven skeletal muscles, which could be impactful in developing strategies aimed at attenuating this comorbidity.
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Fatiga/enzimología , Proteínas de la Membrana/metabolismo , Músculo Esquelético/enzimología , Consumo de Oxígeno , Enfisema Pulmonar/enzimología , Animales , Modelos Animales de Enfermedad , Fatiga/genética , Fatiga/patología , Fatiga/fisiopatología , Proteínas de la Membrana/genética , Ratones , Ratones Transgénicos , Músculo Esquelético/patología , Músculo Esquelético/fisiopatología , Enfisema Pulmonar/genética , Enfisema Pulmonar/patología , Enfisema Pulmonar/fisiopatologíaRESUMEN
The COVID19 pandemic has caused more than a million of deaths worldwide, primarily due to complications from COVID19-associated acute respiratory distress syndrome (ARDS). Controversy surrounds the circulating cytokine/chemokine profile of COVID19-associated ARDS, with some groups suggesting that it is similar to patients without COVID19 ARDS and others observing substantial differences. Moreover, although a hyperinflammatory phenotype associates with higher mortality in non-COVID19 ARDS, there is little information on the inflammatory landscape's association with mortality in patients with COVID19 ARDS. Even though the circulating leukocytes' transcriptomic signature has been associated with distinct phenotypes and outcomes in critical illness including ARDS, it is unclear whether the mortality-associated inflammatory mediators from patients with COVID19 are transcriptionally regulated in the leukocyte compartment. Here, we conducted a prospective cohort study of 41 mechanically ventilated patients with COVID19 infection using highly calibrated methods to define the levels of plasma cytokines/chemokines and their gene expressions in circulating leukocytes. Plasma IL1RA and IL8 were found positively associated with mortality, whereas RANTES and EGF negatively associated with that outcome. However, the leukocyte gene expression of these proteins had no statistically significant correlation with mortality. These data suggest a unique inflammatory signature associated with severe COVID19.
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COVID-19/metabolismo , COVID-19/patología , Inflamación/metabolismo , Síndrome de Dificultad Respiratoria/mortalidad , SARS-CoV-2 , Anciano , COVID-19/mortalidad , Estudios de Cohortes , Citocinas/genética , Citocinas/metabolismo , Femenino , Regulación de la Expresión Génica , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Dysfunction of locomotor muscles is frequent in chronic pulmonary diseases and strongly associated with worse outcomes including higher mortality. Although these associations have been corroborated over the last decades, there is poor mechanistic understanding of the process, in part due to the lack of adequate animal models to investigate this process. Most of the mechanistic research has so far been accomplished using relevant individual stimuli such as low oxygen or high CO2 delivered to otherwise healthy animals as surrogates of the phenomena occurring in the clinical setting. This review advocates for the development of a syndromic model in which skeletal muscle dysfunction is investigated as a comorbidity of a well-validated pulmonary disease model, which could potentially allow discovering meaningful mechanisms and pathways and lead to more substantial progress to treat this devastating condition.
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Enfermedades Pulmonares , Insuficiencia Respiratoria , Animales , Comorbilidad , Modelos Animales , Músculo EsqueléticoRESUMEN
High CO2 retention, or hypercapnia, is associated with worse outcomes in patients with chronic pulmonary diseases. Skeletal muscle wasting is also an independent predictor of poor outcomes in patients with acute and chronic pulmonary diseases. Although previous evidence indicates that high CO2 accelerates skeletal muscle catabolism via AMPK (AMP-activated protein kinase)-FoxO3a-MuRF1 (E3-ubiquitin ligase muscle RING finger protein 1), little is known about the role of high CO2 in regulating skeletal muscle anabolism. In the present study, we investigated the potential role of high CO2 in attenuating skeletal muscle protein synthesis. We found that locomotor muscles from patients with chronic CO2 retention demonstrated depressed ribosomal gene expression in comparison with locomotor muscles from non-CO2-retaining individuals, and analysis of the muscle proteome of normo- and hypercapnic mice indicates reduction of important components of ribosomal structure and function. Indeed, mice chronically kept under a high-CO2 environment show evidence of skeletal muscle downregulation of ribosomal biogenesis and decreased protein synthesis as measured by the incorporation of puromycin into skeletal muscle. Hypercapnia did not regulate the mTOR pathway, and rapamycin-induced deactivation of mTOR did not cause a decrease in ribosomal gene expression. Loss-of-function studies in cultured myotubes showed that AMPKα2 regulates CO2-mediated reductions in ribosomal gene expression and protein synthesis. Although previous evidence has implicated TIF1A (transcription initiation factor-1α) and KDM2A (lysine-specific demethylase 2A) in AMPK-driven regulation of ribosomal gene expression, we found that these mediators were not required in the high CO2-induced depressed protein anabolism. Our research supports future studies targeting ribosomal biogenesis and protein synthesis to alleviate the effects of high CO2 on skeletal muscle turnover.
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Proteínas Quinasas Activadas por AMP/metabolismo , Dióxido de Carbono/efectos adversos , Regulación hacia Abajo/efectos de los fármacos , Proteínas Musculares/metabolismo , Músculo Esquelético/efectos de los fármacos , Biosíntesis de Proteínas/efectos de los fármacos , Ribosomas/efectos de los fármacos , Adolescente , Animales , Proteínas F-Box/metabolismo , Expresión Génica/efectos de los fármacos , Humanos , Enfermedades Pulmonares/etiología , Enfermedades Pulmonares/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Músculo Esquelético/metabolismo , Proteínas Nucleares/metabolismo , Ribosomas/metabolismo , Transducción de Señal/efectos de los fármacos , Serina-Treonina Quinasas TOR/metabolismo , Factores de Transcripción/metabolismo , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
BACKGROUND: Reduced body weight at the time of intensive care unit (ICU) admission is associated with worse survival, and a paradoxical benefit of obesity has been suggested in critical illness. However, no research has addressed the survival effects of disaggregated body constituents of dry weight such as skeletal muscle, fat, and bone density. METHODS: Single-center, prospective observational cohort study of medical ICU (MICU) patients from an academic institution in the USA. Five hundred and seven patients requiring CT scanning of chest or abdomen within the first 24 h of ICU admission were evaluated with erector spinae muscle (ESM) and subcutaneous adipose tissue (SAT) areas and with bone density determinations at the time of ICU admission, which were correlated with clinical outcomes accounting for potential confounders. RESULTS: Larger admission ESM area was associated with decreased odds of 6-month mortality (OR per cm2, 0.96; 95% CI, 0.94-0.97; p < 0.001) and disability at discharge (OR per cm2, 0.98; 95% CI, 0.96-0.99; p = 0.012). Higher bone density was similarly associated with lower odds of mortality (OR per 100 HU, 0.69; 95% CI, 0.49-0.96; p = 0.027) and disability at discharge (OR per 100 HU, 0.52; 95% CI, 0.37-0.74; p < 0.001). SAT area was not significantly associated with these outcomes' measures. Multivariable modeling indicated that ESM area remained significantly associated with 6-month mortality and survival after adjusting for other covariates including preadmission comorbidities, albumin, functional independence before admission, severity scores, age, and exercise capacity. CONCLUSION: In our cohort, ICU admission skeletal muscle mass measured with ESM area and bone density were associated with survival and disability at discharge, although muscle area was the only component that remained significantly associated with survival after multivariable adjustments. SAT had no association with the analyzed outcome measures.
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Tejido Adiposo/fisiopatología , Composición Corporal , Huesos/fisiopatología , Músculo Esquelético/fisiopatología , Anciano , Estudios de Cohortes , Femenino , Humanos , Unidades de Cuidados Intensivos/organización & administración , Unidades de Cuidados Intensivos/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Alta del Paciente/estadística & datos numéricos , Estudios Prospectivos , Estudios RetrospectivosRESUMEN
Skeletal muscle dysfunction is a major comorbidity in chronic obstructive pulmonary disease (COPD) and other pulmonary conditions. Chronic CO2 retention, or hypercapnia, also occur in some of these patients. Both muscle dysfunction and hypercapnia associate with higher mortality in these populations. Over the last years, we have established a mechanistic link between hypercapnia and skeletal muscle dysfunction, which is regulated by AMPK and causes depressed anabolism via reduced ribosomal biogenesis and accelerated catabolism via proteasomal degradation. In this review, we discuss the main findings linking AMPK with hypercapnic pulmonary disease both in the lungs and skeletal muscles, and also outline potential avenues for future research in the area based on knowledge gaps and opportunities to expand mechanistic research with translational implications.
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Proteínas Quinasas Activadas por AMP/metabolismo , Hipercapnia/metabolismo , Músculo Esquelético/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/metabolismo , Animales , Dióxido de Carbono/metabolismo , Comorbilidad , Humanos , Atrofia Muscular/metabolismo , Ribosomas/metabolismoRESUMEN
Skeletal muscle dysfunction occurs in patients with chronic obstructive pulmonary disease (COPD) and affects both ventilatory and nonventilatory muscle groups. It represents a very important comorbidity that is associated with poor quality of life and reduced survival. It results from a complex combination of functional, metabolic, and anatomical alterations leading to suboptimal muscle work. Muscle atrophy, altered fiber type and metabolism, and chest wall remodeling, in the case of the respiratory muscles, are relevant etiological contributors to this process. Muscle dysfunction worsens during COPD exacerbations, rendering patients progressively less able to perform activities of daily living, and it is also associated with poor outcomes. Muscle recovery measures consisting of a combination of pulmonary rehabilitation, optimized nutrition, and other strategies are associated with better prognosis when administered in stable patients as well as after exacerbations. A deeper understanding of this process' pathophysiology and clinical relevance will facilitate the use of measures to alleviate its effects and potentially improve patients' outcomes. In this review, a general overview of skeletal muscle dysfunction in COPD is offered to highlight its relevance and magnitude to expert practitioners and scientists as well as to the average clinician dealing with patients with chronic respiratory diseases.
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Debilidad Muscular/etiología , Debilidad Muscular/terapia , Músculo Esquelético/fisiopatología , Atrofia Muscular/etiología , Atrofia Muscular/terapia , Enfermedad Pulmonar Obstructiva Crónica/complicaciones , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Músculos Respiratorios/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Comorbilidad , Femenino , Humanos , Masculino , Persona de Mediana EdadAsunto(s)
COVID-19 , Humanos , Secuenciación Completa del Genoma , Metilación de ADN , Epigénesis Genética , HospitalesRESUMEN
Pulmonary hypertension (PH) is characterized by increased vasoconstriction and smooth muscle cell hyperplasia driving pathological vascular remodeling of arterial vessels. In this short review, we discuss the primary source of reactive oxygen species (ROS) and nitric oxide (NO) relevant to PH and the mechanism by which dysregulation of their production contributes to PH. Specifically, hypoxia-induced PH is associated with diminished endothelial nitric oxide synthase (eNOS)-derived NO production and increased production of superoxide (O2â¢-) through eNOS uncoupling and defective mitochondrial respiration. This drives the inhibition of the NO/soluble guanylate cyclase (sGC) pathway and activation of the transcription factor hypoxia-inducible factor-1α (HIF-1α) with consequential dysregulation of the pulmonary vasculature. Therapeutics aimed at increasing NO or cGMP bioavailabilities are amenable to hypoxia disease-induced PH. Similarly, strategies targeting HIF-1α are now considered. Overall, pulmonary hypertension including hypoxia-induced PH offers unique opportunities for the rational development of therapeutics centered on modulating redox signaling.
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Hipertensión Pulmonar/metabolismo , Óxido Nítrico/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal , Animales , Humanos , Hipertensión Pulmonar/fisiopatología , Hipoxia , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Superóxidos/metabolismoRESUMEN
Patients with chronic obstructive pulmonary disease, acute lung injury, and critical care illness may develop hypercapnia. Many of these patients often have muscle dysfunction which increases morbidity and impairs their quality of life. Here, we investigated whether hypercapnia leads to skeletal muscle atrophy. Mice exposed to high CO2 had decreased skeletal muscle wet weight, fiber diameter, and strength. Cultured myotubes exposed to high CO2 had reduced fiber diameter, protein/DNA ratios, and anabolic capacity. High CO2 induced the expression of MuRF1 in vivo and in vitro, whereas MuRF1(-/-) mice exposed to high CO2 did not develop muscle atrophy. AMP-activated kinase (AMPK), a metabolic sensor, was activated in myotubes exposed to high CO2, and loss-of-function studies showed that the AMPKα2 isoform is necessary for muscle-specific ring finger protein 1 (MuRF1) up-regulation and myofiber size reduction. High CO2 induced AMPKα2 activation, triggering the phosphorylation and nuclear translocation of FoxO3a, and leading to an increase in MuRF1 expression and myotube atrophy. Accordingly, we provide evidence that high CO2 activates skeletal muscle atrophy via AMPKα2-FoxO3a-MuRF1, which is of biological and potentially clinical significance in patients with lung diseases and hypercapnia.
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Adenilato Quinasa/metabolismo , Dióxido de Carbono/metabolismo , Factores de Transcripción Forkhead/metabolismo , Proteínas Musculares/metabolismo , Músculo Esquelético/patología , Atrofia Muscular/etiología , Ubiquitina-Proteína Ligasas/metabolismo , Animales , Secuencia de Bases , Línea Celular , Cartilla de ADN , Proteína Forkhead Box O3 , Masculino , Ratones , Ratones Endogámicos C57BL , Músculo Esquelético/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Proteínas de Motivos Tripartitos , Regulación hacia ArribaAsunto(s)
Biomarcadores/metabolismo , Músculo Esquelético/metabolismo , Condicionamiento Físico Animal/fisiología , Enfermedad Pulmonar Obstructiva Crónica/metabolismo , Enfisema Pulmonar/metabolismo , Animales , Modelos Animales de Enfermedad , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Músculo Esquelético/fisiopatología , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Enfisema Pulmonar/fisiopatologíaRESUMEN
BACKGROUND: DNA methylation integrates environmental signals with transcriptional programs. COVID-19 infection induces changes in the host methylome. While post-acute sequelae of COVID-19 (PASC) is a long-term complication of acute illness, its association with DNA methylation is unknown. No universal blood marker of PASC, superseding single organ dysfunctions, has yet been identified. METHODS: In this single centre prospective cohort study, PASC, post-COVID without PASC, and healthy participants were enrolled to investigate their symptoms association with peripheral blood DNA methylation data generated with state-of-the-art whole genome sequencing. PASC-induced quality-of-life deterioration was scored with a validated instrument, SF-36. Analyses were conducted to identify potential functional roles of differentially methylated loci, and machine learning algorithms were used to resolve PASC severity. FINDINGS: 103 patients with PASC (22.3% male, 77.7% female), 15 patients with previous COVID-19 infection but no PASC (40.0% male, 60.0% female), and 27 healthy volunteers (48.1% male, 51.9% female) were enrolled. Whole genome methylation sequencing revealed 39 differentially methylated regions (DMRs) specific to PASC, each harbouring an average of 15 consecutive positions, that differentiate patients with PASC from the two control groups. Motif analyses of PASC-regulated DMRs identify binding domains for transcription factors regulating circadian rhythm and others. Some DMRs annotated to protein coding genes were associated with changes of RNA expression. Machine learning support vector algorithm and random forest hierarchical clustering reveal 28 unique differentially methylated positions (DMPs) in the genome discriminating patients with better and worse quality of life. INTERPRETATION: Blood DNA methylation levels identify PASC, stratify PASC severity, and suggest that DNA motifs are targeted by circadian rhythm-regulating pathways in PASC. FUNDING: This project has been funded by the following agencies: NIH-AI173035 (A. Jaitovich and R. Alisch); and NIH-AG066179 (R. Alisch).
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COVID-19 , Metilación de ADN , SARS-CoV-2 , Humanos , COVID-19/genética , COVID-19/sangre , COVID-19/virología , Femenino , Masculino , Persona de Mediana Edad , SARS-CoV-2/genética , Estudios Prospectivos , Adulto , Anciano , Síndrome Post Agudo de COVID-19 , Aprendizaje Automático , Secuenciación Completa del Genoma , Biomarcadores/sangre , Calidad de Vida , Betacoronavirus/genéticaRESUMEN
Reduced skeletal muscle mass and oxidative capacity coexist in patients with pulmonary emphysema and are independently associated with higher mortality. If reduced cellular respiration contributes to muscle atrophy in that setting remains unknown. Using a mouse with genetically induced pulmonary emphysema that recapitulates muscle dysfunction, we found that reduced activity of succinate dehydrogenase (SDH) is a hallmark of its myopathic changes. We generated an inducible, muscle-specific SDH knockout mouse that demonstrates lower mitochondrial oxygen consumption, myofiber contractility, and exercise endurance. Respirometry analyses show that in vitro complex I respiration is unaffected by loss of SDH subunit C in muscle mitochondria, which is consistent with the pulmonary emphysema animal data. SDH knockout initially causes succinate accumulation associated with a down-regulated transcriptome but modest proteome effects. Muscle mass, myofiber type composition, and overall body mass constituents remain unaltered in the transgenic mice. Thus, while SDH regulates myofiber respiration in experimental pulmonary emphysema, it does not control muscle mass or other body constituents.
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Respiración de la Célula , Ratones Noqueados , Contracción Muscular , Músculo Esquelético , Enfisema Pulmonar , Succinato Deshidrogenasa , Animales , Enfisema Pulmonar/metabolismo , Enfisema Pulmonar/genética , Enfisema Pulmonar/patología , Enfisema Pulmonar/etiología , Succinato Deshidrogenasa/metabolismo , Succinato Deshidrogenasa/genética , Ratones , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Complejo II de Transporte de Electrones/metabolismo , Complejo II de Transporte de Electrones/genética , Modelos Animales de Enfermedad , Ratones Transgénicos , Mitocondrias Musculares/metabolismo , Mitocondrias Musculares/patología , Consumo de OxígenoRESUMEN
The oxidant hydrogen peroxide serves as a signaling molecule that alters many aspects of cardiovascular functions. Recent studies suggest that cytoglobin - a hemoglobin expressed in the vasculature - may promote electron transfer reactions with proposed functions in hydrogen peroxide decomposition. Here, we determined the extent to which cytoglobin regulates intracellular hydrogen peroxide and established mechanisms. We found that cytoglobin decreased the hyperoxidation of peroxiredoxins and maintained the activity of peroxiredoxin 2 following challenge with exogenous hydrogen peroxide. Cytoglobin promoted a reduced intracellular environment and facilitated the reduction of the thiol-based hydrogen peroxide sensor Hyper7 after bolus addition of hydrogen peroxide. Cytoglobin also limited the inhibitory effect of hydrogen peroxide on glycolysis and reversed the oxidative inactivation of the glycolytic enzyme GAPDH. Our results indicate that cytoglobin in cells exists primarily as oxyferrous cytoglobin (CygbFe 2+ -O 2 ) with its cysteine residues in the reduced form. We found that the specific substitution of one of two cysteine residues on cytoglobin (C83A) inhibited the reductive activity of cytoglobin on Hyper7 and GAPDH. Carotid arteries from cytoglobin knockout mice were more sensitive to glycolytic inhibition by hydrogen peroxide than arteries from wildtype mice. Together, these results support a role for cytoglobin in regulating intracellular redox signals associated with hydrogen peroxide through oxidation of its cysteine residues, independent of hydrogen peroxide reaction at its heme center.
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Cartilage acidic protein-1 (CRTAC1) is produced by several cell types, including Type 2 alveolar epithelial (T2AE) cells that are targeted by SARS-CoV2. Plasma CRTAC1 is known based on proteomic surveys to be low in patients with severe COVID-19. Using an ELISA, we found that patients treated for COVID-19 in an ICU almost uniformly had plasma concentrations of CRTAC1 below those of healthy controls. Magnitude of decrease in CRTAC1 distinguished COVID-19 from other causes of acute respiratory decompensation and correlated with established metrics of COVID-19 severity. CRTAC1 concentrations below those of controls were found in some patients a year after hospitalization with COVID-19, long COVID after less severe COVID-19, or chronic obstructive pulmonary disease. Decreases in CRTAC1 in severe COVID-19 correlated (r = 0.37, p = 0.0001) with decreases in CFP (properdin), which interacts with CRTAC1. Thus, decreases of CRTAC1 associated with severe COVID-19 may result from loss of production by T2AE cells or co-depletion with CFP. Determination of significance of and reasons behind decreased CRTAC1 concentration in a subset of patients with long COVID will require analysis of roles of preexisting lung disease, impact of prior acute COVID-19, age, and other confounding variables in a larger number of patients.
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COVID-19 , Proteínas de Unión al Calcio , Humanos , Proteínas de Unión al Calcio/sangre , Síndrome Post Agudo de COVID-19 , Proteómica , ARN Viral , SARS-CoV-2RESUMEN
Identifying novel regulators of vascular smooth muscle cell function is necessary to further understand cardiovascular diseases. We previously identified cytoglobin, a hemoglobin homolog, with myogenic and cytoprotective roles in the vasculature. The specific mechanism of action of cytoglobin is unclear but does not seem to be related to oxygen transport or storage like hemoglobin. Herein, transcriptomic profiling of injured carotid arteries in cytoglobin global knockout mice revealed that cytoglobin deletion accelerated the loss of contractile genes and increased DNA damage. Overall, we show that cytoglobin is actively translocated into the nucleus of vascular smooth muscle cells through a redox signal driven by NOX4. We demonstrate that nuclear cytoglobin heterodimerizes with the non-histone chromatin structural protein HMGB2. Our results are consistent with a previously unknown function by which a non-erythrocytic hemoglobin inhibits DNA damage and regulates gene programs in the vasculature by modulating the genome-wide binding of HMGB2.
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Globinas , Proteína HMGB2 , Animales , Ratones , Citoglobina/genética , Daño del ADN , Globinas/genética , Globinas/metabolismo , Proteína HMGB2/genética , Proteína HMGB2/metabolismo , Factores de Transcripción/genéticaRESUMEN
Identifying novel regulators of vascular smooth muscle cell function is necessary to further understand cardiovascular diseases. We previously identified cytoglobin, a hemoglobin homolog, with myogenic and cytoprotective roles in the vasculature. The specific mechanism of action of cytoglobin is unclear but does not seem to be related to oxygen transport or storage like hemoglobin. Herein, transcriptomic profiling of injured carotid arteries in cytoglobin global knockout mice revealed that cytoglobin deletion accelerated the loss of contractile genes and increased DNA damage. Overall, we show that cytoglobin is actively translocated into the nucleus of vascular smooth muscle cells through a redox signal driven by NOX4. We demonstrate that nuclear cytoglobin heterodimerizes with the non-histone chromatin structural protein HMGB2. Our results are consistent with a previously unknown function by which a non-erythrocytic hemoglobin inhibits DNA damage and regulates gene programs in the vasculature by modulating the genome-wide binding of HMGB2.