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Tumor-infiltrating lymphocyte (TIL) adoptive cell therapy is effective in treating malignant melanoma, but its success relies on the adequate ex vivo expansion of TIL. To assess correlates of TIL expansion, CD4+ and CD8+ TIL were analyzed by RNA sequencing (RNA-seq) and chromatin immunoprecipitation sequencing of acetylated histone 3. Patients were grouped into "TIL high" and "TIL low" based on division at the median number of TIL infused. Greater numbers of TIL infused correlated with longer overall survival, and increased frequencies of CD4+ cells infused were negatively correlated with the number of TIL infused. RNA-seq analysis of CD4+ TIL showed increases in Th2/Th17/regulatory T cell-related transcripts and pathways in the TIL-low group. Analysis of a public single-cell RNA-seq dataset validated findings that increased frequencies of CD4+ cells were negatively correlated with the number of TIL infused. TIL-low patients had significantly increased frequencies of CD4+ cells expressing ETS2 and OSM and trended toward increased expression of TNFRSF18.
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Linfocitos Infiltrantes de Tumor , Melanoma , Humanos , Linfocitos Infiltrantes de Tumor/patología , Inmunoterapia Adoptiva , Interleucina-2 , Melanoma/terapia , Melanoma/patología , FenotipoRESUMEN
Over the last century, outbreaks and pandemics have occurred with disturbing regularity, necessitating advance preparation and large-scale, coordinated response. Here, we developed a machine learning predictive model of disease severity and length of hospitalization for COVID-19, which can be utilized as a platform for future unknown viral outbreaks. We combined untargeted metabolomics on plasma data obtained from COVID-19 patients (n = 111) during hospitalization and healthy controls (n = 342), clinical and comorbidity data (n = 508) to build this patient triage platform, which consists of three parts: (i) the clinical decision tree, which amongst other biomarkers showed that patients with increased eosinophils have worse disease prognosis and can serve as a new potential biomarker with high accuracy (AUC = 0.974), (ii) the estimation of patient hospitalization length with ± 5 days error (R2 = 0.9765) and (iii) the prediction of the disease severity and the need of patient transfer to the intensive care unit. We report a significant decrease in serotonin levels in patients who needed positive airway pressure oxygen and/or were intubated. Furthermore, 5-hydroxy tryptophan, allantoin, and glucuronic acid metabolites were increased in COVID-19 patients and collectively they can serve as biomarkers to predict disease progression. The ability to quickly identify which patients will develop life-threatening illness would allow the efficient allocation of medical resources and implementation of the most effective medical interventions. We would advocate that the same approach could be utilized in future viral outbreaks to help hospitals triage patients more effectively and improve patient outcomes while optimizing healthcare resources.
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COVID-19 , Humanos , COVID-19/epidemiología , Triaje , Alantoína , Brotes de Enfermedades , Aprendizaje AutomáticoRESUMEN
BACKGROUND: Aortic dissection (AD) is a vascular emergency with time-dependent mortality. Point-of-care ultrasound (POCUS) and AD risk score (ADRS) have been proposed as diagnostic tools to risk stratify patients and reduce time to diagnosis. STUDY OBJECTIVE: We evaluate POCUS findings and ADRS in a retrospective cohort of patients with known type A AD. The objective of this study is to describe the prevalence of POCUS findings and ADRS in this population. METHODS: This is a retrospective cohort study of patients with acute type A AD as confirmed on computed tomography scan over a 12-year period from 2008 to 2020, with a subgroup analysis of patients who received POCUS in the emergency department. ADRS was calculated and POCUS findings were reviewed. Descriptive statistics were used to describe the distribution of POCUS findings. RESULTS: Ninety-one patients met inclusion criteria. POCUS was performed in 41 but only 35 had images of adequate quality for inclusion. Of the POCUS images available, 30/35 (86%) patients had a POCUS finding consistent with dissection and 5/35 (14%) had no findings on POCUS. Twelve percent (11/91) of patients had ADRS = 0. Two patients with ADRS = 0 received POCUS, and one patient had no findings on POCUS. CONCLUSION: Although POCUS provides rapid information in the diagnosis of type A AD, 14% of patients with images available for review had no findings on POCUS. Of the whole cohort, 12% had an ADRS = 0. Further studies are needed to identify an optimal diagnostic pathway for this catastrophic disease.
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Disección Aórtica , Servicio de Urgencia en Hospital , Sistemas de Atención de Punto , Ultrasonografía , Humanos , Estudios Retrospectivos , Disección Aórtica/diagnóstico , Disección Aórtica/diagnóstico por imagen , Disección Aórtica/epidemiología , Masculino , Femenino , Sistemas de Atención de Punto/normas , Sistemas de Atención de Punto/estadística & datos numéricos , Ultrasonografía/métodos , Ultrasonografía/estadística & datos numéricos , Persona de Mediana Edad , Anciano , Servicio de Urgencia en Hospital/organización & administración , Medición de Riesgo/métodos , Estudios de Cohortes , Tomografía Computarizada por Rayos X/métodos , Tomografía Computarizada por Rayos X/estadística & datos numéricos , AdultoRESUMEN
Intermediate filament (IntFil) genes arose during early metazoan evolution, to provide mechanical support for plasma membranes contacting/interacting with other cells and the extracellular matrix. Keratin genes comprise the largest subset of IntFil genes. Whereas the first keratin gene appeared in sponge, and three genes in arthropods, more rapid increases in keratin genes occurred in lungfish and amphibian genomes, concomitant with land animal-sea animal divergence (~ 440 to 410 million years ago). Human, mouse and zebrafish genomes contain 18, 17 and 24 non-keratin IntFil genes, respectively. Human has 27 of 28 type I "acidic" keratin genes clustered at chromosome (Chr) 17q21.2, and all 26 type II "basic" keratin genes clustered at Chr 12q13.13. Mouse has 27 of 28 type I keratin genes clustered on Chr 11, and all 26 type II clustered on Chr 15. Zebrafish has 18 type I keratin genes scattered on five chromosomes, and 3 type II keratin genes on two chromosomes. Types I and II keratin clusters-reflecting evolutionary blooms of keratin genes along one chromosomal segment-are found in all land animal genomes examined, but not fishes; such rapid gene expansions likely reflect sudden requirements for many novel paralogous proteins having divergent functions to enhance species survival following sea-to-land transition. Using data from the Genotype-Tissue Expression (GTEx) project, tissue-specific keratin expression throughout the human body was reconstructed. Clustering of gene expression patterns revealed similarities in tissue-specific expression patterns for previously described "keratin pairs" (i.e., KRT1/KRT10, KRT8/KRT18, KRT5/KRT14, KRT6/KRT16 and KRT6/KRT17 proteins). The ClinVar database currently lists 26 human disease-causing variants within the various domains of keratin proteins.
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Queratinas , Pez Cebra , Animales , Genoma , Queratinas/genética , Queratinas Tipo I/genética , RatonesRESUMEN
Following the draft sequence of the first human genome over 20 years ago, we have achieved unprecedented insights into the rules governing its evolution, often with direct translational relevance to specific diseases. However, staggering sequence complexity has also challenged the development of a more comprehensive understanding of human genome biology. In this context, interspecific genomic studies between humans and other animals have played a critical role in our efforts to decode human gene families. In this review, we focus on how the rapid surge of genome sequencing of both model and non-model organisms now provides a broader comparative framework poised to empower novel discoveries. We begin with a general overview of how comparative approaches are essential for understanding gene family evolution in the human genome, followed by a discussion of analyses of gene expression. We show how homology can provide insights into the genes and gene families associated with immune response, cancer biology, vision, chemosensation, and metabolism, by revealing similarity in processes among distant species. We then explain methodological tools that provide critical advances and show the limitations of common approaches. We conclude with a discussion of how these investigations position us to gain fundamental insights into the evolution of gene families among living organisms in general. We hope that our review catalyzes additional excitement and research on the emerging field of comparative genomics, while aiding the placement of the human genome into its existentially evolutionary context.
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Evolución Molecular , Genómica , Animales , Humanos , Genoma , Secuencia de Bases , FilogeniaRESUMEN
BACKGROUND: This report describes two L. monocytogenes outbreak investigations that occurred in March and September of 2018 and that linked illness to a food premises located in an Ontario cancer centre. The cancer centre serves patients from across the province. METHODS: In Ontario, local public health agencies follow up with all reported laboratory-confirmed cases of listeriosis to identify possible sources of disease acquisition and to carry out investigations, including at suspected food premises. The Canadian Food Inspection Agency (CFIA) is notified of any Listeria-positive food product collected in relation to a case. The CFIA traces Listeria-positive product through the food distribution system to identify the contamination source and ensure the implicated manufacturing facility implements corrective measures. RESULTS: Outbreaks one and two each involved three outbreak-confirmed listeriosis cases. All six cases were considered genetically related by whole genome sequencing (WGS). In both outbreaks, outbreak-confirmed cases reported consuming meals at a food premises located in a cancer centre (food premises A) before illness onset. Various open deli meat samples and, in outbreak two, environmental swabs (primarily from the meat slicer) collected from food premises A were genetically related to the outbreak-confirmed cases. Food premises A closed as a result of the investigations. CONCLUSIONS: When procuring on-site food premises, healthcare facilities and institutions serving individuals with immuno-compromising conditions should consider the potential health risk of foods available to their patient population.
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Enfermedades Transmitidas por los Alimentos , Listeria monocytogenes , Listeriosis , Neoplasias , Humanos , Listeria monocytogenes/genética , Enfermedades Transmitidas por los Alimentos/epidemiología , Microbiología de Alimentos , Neoplasias/epidemiología , Listeriosis/epidemiología , Brotes de Enfermedades , Ontario/epidemiologíaRESUMEN
Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis are the major pathogens of the spore-forming genus Bacillus and possess an outer spore layer, the exosporium, not found in many of the nonpathogenic species. The exosporium consists of a basal layer with the ExsY, CotY, and BxpB proteins being the major structural components and an exterior nap layer containing the BclA glycoprotein. During the assembly process, the nascent exosporium basal layer is attached to the spore coat by a protein linker that includes the CotO and CotE proteins. Using transmission electron microscopy, Western blotting, immunofluorescence, and fluorescent fusion protein approaches, we examined the impact of single, double, and triple mutants of the major exosporium proteins on exosporium protein content and distribution. Plasmid-based expression of exsY and cotE resulted in increased production of exosporium lacking spores, and the former also resulted in outer spore coat disruptions. The exosporium bottlecap produced by exsY null spores was found to be more stable than previously reported, and its spore association was partially dependent on CotE. Deletion mutants of five putative spore genes (bas1131, bas1142, bas1143, bas2277, and bas3594) were created and shown not to have obvious effects on spore morphology or BclA and BxpB content. The BclC collagen-like glycoprotein was found to be present in the spore and possibly localized to the interspace region. IMPORTANCE B. anthracis is an important zoonotic animal pathogen causing sporadic outbreaks of anthrax worldwide. Spores are the infectious form of the bacterium and can persist in soil for prolonged periods of time. The outermost B. anthracis spore layer is the exosporium, a protein shell that is the site of interactions with both the soil and with the innate immune system of infected hosts. Although much is known regarding the sporulation process among members of the genus Bacillus, significant gaps in our understanding of the exosporium assembly process exist. This study provides evidence for the properties of key exosporium basal layer structural proteins. The results of this work will guide future studies on exosporium protein-protein interactions during the assembly process.
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Bacillus anthracis , Bacillus , Bacillus anthracis/metabolismo , Esporas Bacterianas/metabolismo , Proteínas Bacterianas/metabolismo , Glicoproteínas de Membrana/química , Bacillus/metabolismo , Glicoproteínas/metabolismo , SueloRESUMEN
Within the discipline of anatomical education, the use of donated human cadavers in laboratory-based learning activities is often described as the 'gold standard' resource for supporting student understanding of anatomy. Due to both historical and educational factors, cadaveric dissection has traditionally been the approach against which other anatomy learning modalities and resources have been judged. To prepare human donors for teaching purposes, bodies must be embalmed with fixative agents to preserve the tissues. Embalmed cadavers can then be dissected by students or can be prosected or plastinated to produce teaching resources. Here, we describe the history of cadaveric preservation in anatomy education and review the practical strengths and limitations of current approaches for the embalming of human bodies. Furthermore, we investigate the pedagogic benefits of a range of established modern embalming techniques. We describe relevant cadaveric attributes and their impacts on learning, including the importance of colour, texture, smell, and joint mobility. We also explore the emotional and humanistic elements of the use of human donors in anatomy education, and the relative impact of these factors when alternative types of embalming process are performed. Based on these underpinnings, we provide a technical description of our modern Newcastle-WhitWell embalming process. In doing so, we aim to inform anatomy educators and technical staff seeking to embalm human donors rapidly and safely and at reduced costs, while enhancing visual and haptic tissue characteristics. We propose that our technique has logistical and pedagogic implications, both for the development of embalming techniques and for student visualisation and learning.
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Disección , Embalsamiento , Cadáver , Fijadores , Humanos , Rango del Movimiento ArticularRESUMEN
The cardiac sarcomere is a triumph of biological evolution wherein myriad contractile and regulatory proteins assemble into a quasi-crystalline lattice to serve as the central point upon which cardiac muscle contraction occurs. This review focuses on the many signaling components and mechanisms of regulation that impact cardiac sarcomere function. We highlight the roles of the thick and thin filament, both as necessary structural and regulatory building blocks of the sarcomere as well as targets of functionally impactful modifications. Currently, a new focus emerging in the field is inter-myofilament signaling, and we discuss here the important mediators of this mechanism, including myosin-binding protein C and titin. As the understanding of sarcomere signaling advances, so do the methods with which it is studied. This is reviewed here through discussion of recent live muscle systems in which the sarcomere can be studied under intact, physiologically relevant conditions.
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Miocardio , Sarcómeros , Sarcómeros/metabolismo , Miocardio/metabolismo , Corazón/fisiología , Conectina/metabolismo , Miofibrillas/fisiología , Contracción Miocárdica/fisiologíaRESUMEN
Paired-box (PAX) genes encode a family of highly conserved transcription factors found in vertebrates and invertebrates. PAX proteins are defined by the presence of a paired domain that is evolutionarily conserved across phylogenies. Inclusion of a homeodomain and/or an octapeptide linker subdivides PAX proteins into four groups. Often termed "master regulators", PAX proteins orchestrate tissue and organ development throughout cell differentiation and lineage determination, and are essential for tissue structure and function through maintenance of cell identity. Mutations in PAX genes are associated with myriad human diseases (e.g., microphthalmia, anophthalmia, coloboma, hypothyroidism, acute lymphoblastic leukemia). Transcriptional regulation by PAX proteins is, in part, modulated by expression of alternatively spliced transcripts. Herein, we provide a genomics update on the nine human PAX family members and PAX homologs in 16 additional species. We also present a comprehensive summary of human tissue-specific PAX transcript variant expression and describe potential functional significance of PAX isoforms. While the functional roles of PAX proteins in developmental diseases and cancer are well characterized, much remains to be understood regarding the functional roles of PAX isoforms in human health. We anticipate the analysis of tissue-specific PAX transcript variant expression presented herein can serve as a starting point for such research endeavors.
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Predisposición Genética a la Enfermedad , Factores de Transcripción Paired Box/genética , Empalme Alternativo , Animales , Mapeo Cromosómico , Evolución Molecular , Humanos , Filogenia , ARN Mensajero/genética , Transcripción GenéticaRESUMEN
Advancing maturation of stem cell-derived cardiac muscle represents a major barrier to progress in cardiac regenerative medicine. Cardiac muscle maturation involves a myriad of gene, protein, and cell-based transitions, spanning across all aspects of cardiac muscle form and function. We focused here on a key developmentally controlled transition in the cardiac sarcomere, the functional unit of the heart. Using a gene-editing platform, human induced pluripotent stem cell (hiPSCs) were engineered with a drug-inducible expression cassette driving the adult cardiac troponin I (cTnI) regulatory isoform, a transition shown to be a rate-limiting step in advancing sarcomeric maturation of hiPSC cardiac muscle (hiPSC-CM) toward the adult state. Findings show that induction of the adult cTnI isoform resulted in the physiological acquisition of adult-like cardiac contractile function in hiPSC-CMs in vitro. Specifically, cTnI induction accelerated relaxation kinetics at baseline conditions, a result independent of alterations in the kinetics of the intracellular Ca2+ transient. In comparison, isogenic unedited hiPSC-CMs had no cTnI induction and no change in relaxation function. Temporal control of adult cTnI isoform induction did not alter other developmentally regulated sarcomere transitions, including myosin heavy chain isoform expression, nor did it affect expression of SERCA2a or phospholamban. Taken together, precision genetic targeting of sarcomere maturation via inducible TnI isoform switching enables physiologically relevant adult myocardium-like contractile adaptations that are essential for beat-to-beat modulation of adult human heart performance. These findings have relevance to hiPSC-CM structure-function and drug-discovery studies in vitro, as well as for potential future clinical applications of physiologically optimized hiPSC-CM in cardiac regeneration/repair.
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Diferenciación Celular , Edición Génica , Células Madre Pluripotentes Inducidas/citología , Miocardio/citología , Troponina I/genética , Adulto , Línea Celular , Regulación de la Expresión Génica , Genoma Humano , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Contracción Miocárdica , Miocitos Cardíacos/citología , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Reproducibilidad de los Resultados , Troponina I/metabolismoRESUMEN
The sarcomere is the functional unit of cardiac muscle, essential for normal heart function. To date, it has not been possible to study, in real time, thin filament-based activation dynamics in live cardiac muscle. We report here results from a cardiac troponin C (TnC) FRET-based biosensor integrated into the cardiac sarcomere via stoichiometric replacement of endogenous TnC. The TnC biosensor provides, for the first time, evidence of multiple thin filament activating ligands, including troponin I interfacing with TnC and cycling myosin, during a cardiac twitch. Results show that the TnC FRET biosensor transient significantly precedes that of peak twitch force. Using small molecules and genetic modifiers known to alter sarcomere activation, independently of the intracellular Ca2+ transient, the data show that the TnC biosensor detects significant effects of the troponin I switch domain as a sarcomere-activating ligand. Interestingly, the TnC biosensor also detected the effects of load-dependent altered myosin cycling, as shown by a significant delay in TnC biosensor transient inactivation during the isometric twitch. In addition, the TnC biosensor detected the effects of myosin as an activating ligand during the twitch by using a small molecule that directly alters cross-bridge cycling, independently of the intracellular Ca2+ transient. Collectively, these results aid in illuminating the basis of cardiac muscle contractile activation with implications for gene, protein, and small molecule-based strategies designed to target the sarcomere in regulating beat-to-beat heart performance in health and disease.
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Técnicas Biosensibles , Contracción Miocárdica/fisiología , Miocardio/metabolismo , Miofibrillas/metabolismo , Sarcómeros/metabolismo , Animales , Femenino , Ligandos , Masculino , Ratones Endogámicos C57BL , Mutación/genética , Miocitos Cardíacos/metabolismo , Miosinas/metabolismo , Ratas Sprague-Dawley , Troponina C/metabolismo , Troponina I/metabolismoRESUMEN
Retinoic acid (RA) is a potent morphogen required for embryonic development. RA is formed in a multistep process from vitamin A (retinol); RA acts in a paracrine fashion to shape the developing eye and is essential for normal optic vesicle and anterior segment formation. Perturbation in RA-signaling can result in severe ocular developmental diseases-including microphthalmia, anophthalmia, and coloboma. RA-signaling is also essential for embryonic development and life, as indicated by the significant consequences of mutations in genes involved in RA-signaling. The requirement of RA-signaling for normal development is further supported by the manifestation of severe pathologies in animal models of RA deficiency-such as ventral lens rotation, failure of optic cup formation, and embryonic and postnatal lethality. In this review, we summarize RA-signaling, recent advances in our understanding of this pathway in eye development, and the requirement of RA-signaling for embryonic development (e.g., organogenesis and limb bud development) and life.
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Ojo/metabolismo , Transducción de Señal/genética , Tretinoina/metabolismo , Animales , Ojo/embriología , Regulación de la Expresión Génica , Humanos , FenotipoRESUMEN
Prodrug discovery and development in the pharmaceutical industry have been hampered by a lack of knowledge of prodrug activation pathways. Such knowledge would minimize the risks of prodrug failure by enabling proper selection of preclinical animal models, prediction of pharmacogenomic variability, and identification of drug-drug interactions. Technologies for annotation of activating enzymes have not kept pace with the growing need. Activity-based protein profiling (ABPP) has matured considerably in recent decades, leading to widespread use in the pharmaceutical industry. Here, we report the extension of competitive ABPP (cABPP) to prodrug-activating enzyme identification in stable isotope-labeled cell lysates using a modified fluorophosphonate probe. Focusing on the antiviral ester prodrug valacyclovir (VACV), we identified serine hydrolase RBBP9 as an activating enzyme in Caco-2 cells via shotgun proteomics, validating the activity via the selective inhibitor emetine (EME). Kinetic characterization of RBBP9 revealed a catalytic efficiency (kcat·KM-1 = 104 mM-1·s-1) comparable to that of BPHL, the only known VACV-activating enzyme prior to this work. EME incubation in wild-type and Bphl-knockout jejunum and liver lysates demonstrated the near-exclusivity of VACV activation by RBBP9 in the intestine. Additionally, these studies showed that RBBP9 and BPHL are the two major and coequal VACV-activating enzymes in the liver. Single-pass intestinal perfusions of VACV ± EME in mice showed EME coperfusion significantly inhibited the intestinal activation of VACV, implying the in vivo relevance of RBBP9-mediated VACV activation. We envision that others might use the cABPP approach in the future for global, rapid, and efficient discovery of prodrug-activating enzymes.
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Proteínas de Ciclo Celular/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas de Neoplasias/metabolismo , Proteómica/métodos , Valaciclovir/metabolismo , Activación Metabólica , Animales , Células CACO-2 , Proteínas de Ciclo Celular/antagonistas & inhibidores , Humanos , Péptidos y Proteínas de Señalización Intracelular/antagonistas & inhibidores , Ratones , Ratones Endogámicos C57BL , Proteínas de Neoplasias/antagonistas & inhibidores , Profármacos/metabolismoRESUMEN
Nucleic acid - protein interactions are critical for regulating gene activation in the nucleus. In the cytoplasm, however, potential nucleic acid-protein functional interactions are less clear. The emergence of a large and expanding number of non-coding RNAs and DNA fragments raises the possibility that the cytoplasmic nucleic acids may interact with cytoplasmic cellular components to directly alter key biological processes within the cell. We now show that both natural and synthetic nucleic acids, collectively XNAs, when introduced to the cytoplasm of live cell cardiac myocytes, markedly enhance contractile function via a mechanism that is independent of new translation, activation of the TLR-9 pathway or by altered intracellular Ca2+ cycling. Findings show a steep XNA oligo length-dependence, but not sequence dependence or nucleic acid moiety dependence, for cytoplasmic XNAs to hasten myocyte relaxation. XNAs localized to the sarcomere in a striated pattern and bound the cardiac troponin regulatory complex with high affinity in an electrostatic-dependent manner. Mechanistically, XNAs phenocopy PKA-based modified troponin to cause faster relaxation. Collectively, these data support a new role for cytoplasmic nucleic acids in directly modulating live cell cardiac performance and raise the possibility that cytoplasmic nucleic acid - protein interactions may alter functionally relevant pathways in other cell types.
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Calcio/metabolismo , Citoplasma/metabolismo , ADN/metabolismo , Miocitos Cardíacos/metabolismo , ARN no Traducido/metabolismo , Sarcómeros/metabolismo , Animales , Contracción Miocárdica , Miocitos Cardíacos/citología , RatasRESUMEN
The heterotrimeric cardiac troponin complex is a key regulator of contraction and plays an essential role in conferring Ca2+ sensitivity to the sarcomere. During ischemic injury, rapidly accumulating protons acidify the myoplasm, resulting in markedly reduced Ca2+ sensitivity of the sarcomere. Unlike the adult heart, sarcomeric Ca2+ sensitivity in fetal cardiac tissue is comparatively pH insensitive. Replacement of the adult cardiac troponin I (cTnI) isoform with the fetal troponin I (ssTnI) isoform renders adult cardiac contractile machinery relatively insensitive to acidification. Alignment and functional studies have determined histidine 132 of ssTnI to be the predominant source of this pH insensitivity. Substitution of histidine at the cognate position 164 in cTnI confers the same pH insensitivity to adult cardiac myocytes. An alanine at position 164 of cTnI is conserved in all mammals, with the exception of the platypus, which expresses a proline. Prolines are biophysically unique because of their innate conformational rigidity and helix-disrupting function. To provide deeper structure-function insight into the role of the TnC-TnI interface in determining contractility, we employed a live-cell approach alongside molecular dynamics simulations to ascertain the chemo-mechanical implications of the disrupted helix 4 of cTnI where position 164 exists. This important motif belongs to the critical switch region of cTnI. Substitution of a proline at position 164 of cTnI in adult rat cardiac myocytes causes increased contractility independent of alterations in the Ca2+ transient. Free-energy perturbation calculations of cTnC-Ca2+ binding indicate no difference in cTnC-Ca2+ affinity. Rather, we propose the enhanced contractility is derived from new salt bridge interactions between cTnI helix 4 and cTnC helix A, which are critical in determining pH sensitivity and contractility. Molecular dynamics simulations demonstrate that cTnI A164P structurally phenocopies ssTnI under baseline but not acidotic conditions. These findings highlight the evolutionarily directed role of the TnI-cTnC interface in determining cardiac contractility.
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Contracción Miocárdica , Troponina C/química , Troponina C/metabolismo , Troponina I/química , Troponina I/metabolismo , Animales , Femenino , Células HEK293 , Humanos , Simulación de Dinámica Molecular , Unión Proteica , Conformación Proteica en Hélice alfa , Ratas , Ratas Sprague-DawleyRESUMEN
Hypothalamic CAMKK2 represents a potential mechanism for chemically affecting satiety and promoting weight loss in clinically obese patients. Single-digit nanomolar inhibitors of CAMKK2 were identified in three related ATP-competitive series. Limited optimization of kinase selectivity, solubility, and pharmacokinetic properties were undertaken on all three series, as SAR was often transferrable. Ultimately, a 2,4-diaryl 7-azaindole was optimized to afford a tool molecule that potently inhibits AMPK phosphorylation in a hypothalamus-derived cell line, is orally bioavailable, and crosses the blood-brain barrier. When dosed orally in rodents, compound 4â¯t limited ghrelin-induced food intake.
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Quinasa de la Proteína Quinasa Dependiente de Calcio-Calmodulina/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/química , Administración Oral , Animales , Encéfalo/metabolismo , Quinasa de la Proteína Quinasa Dependiente de Calcio-Calmodulina/genética , Quinasa de la Proteína Quinasa Dependiente de Calcio-Calmodulina/metabolismo , Ingestión de Alimentos/efectos de los fármacos , Ghrelina/farmacología , Enlace de Hidrógeno , Indoles/química , Indoles/metabolismo , Concentración 50 Inhibidora , Ratones , Mutagénesis , Inhibidores de Proteínas Quinasas/metabolismoRESUMEN
During progression of atherosclerosis, myeloid cells destabilize lipid-rich plaques in the arterial wall and cause their rupture, thus triggering myocardial infarction and stroke. Survivors of acute coronary syndromes have a high risk of recurrent events for unknown reasons. Here we show that the systemic response to ischaemic injury aggravates chronic atherosclerosis. After myocardial infarction or stroke, Apoe-/- mice developed larger atherosclerotic lesions with a more advanced morphology. This disease acceleration persisted over many weeks and was associated with markedly increased monocyte recruitment. Seeking the source of surplus monocytes in plaques, we found that myocardial infarction liberated haematopoietic stem and progenitor cells from bone marrow niches via sympathetic nervous system signalling. The progenitors then seeded the spleen, yielding a sustained boost in monocyte production. These observations provide new mechanistic insight into atherogenesis and provide a novel therapeutic opportunity to mitigate disease progression.