RESUMEN
Early atherosclerosis depends upon responses by immune cells resident in the intimal aortic wall. Specifically, the healthy intima is thought to be populated by vascular dendritic cells (DCs) that, during hypercholesterolemia, initiate atherosclerosis by being the first to accumulate cholesterol. Whether these cells remain key players in later stages of disease is unknown. Using murine lineage-tracing models and gene expression profiling, we reveal that myeloid cells present in the intima of the aortic arch are not DCs but instead specialized aortic intima resident macrophages (MacAIR) that depend upon colony-stimulating factor 1 and are sustained by local proliferation. Although MacAIR comprise the earliest foam cells in plaques, their proliferation during plaque progression is limited. After months of hypercholesterolemia, their presence in plaques is overtaken by recruited monocytes, which induce MacAIR-defining genes. These data redefine the lineage of intimal phagocytes and suggest that proliferation is insufficient to sustain generations of macrophages during plaque progression.
Asunto(s)
Aorta/inmunología , Macrófagos/inmunología , Monocitos/inmunología , Placa Aterosclerótica/inmunología , Túnica Íntima/inmunología , Animales , Diferenciación Celular , Linaje de la Célula , Movimiento Celular , Proliferación Celular , Células Cultivadas , Colesterol/metabolismo , Progresión de la Enfermedad , Humanos , Factor Estimulante de Colonias de Macrófagos/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Parabiosis , FagocitosisRESUMEN
The heart either hypertrophies or dilates in response to familial mutations in genes encoding sarcomeric proteins, which are responsible for contraction and pumping. These mutations typically alter calcium-dependent tension generation within the sarcomeres, but how this translates into the spectrum of hypertrophic versus dilated cardiomyopathy is unknown. By generating a series of cardiac-specific mouse models that permit the systematic tuning of sarcomeric tension generation and calcium fluxing, we identify a significant relationship between the magnitude of tension developed over time and heart growth. When formulated into a computational model, the integral of myofilament tension development predicts hypertrophic and dilated cardiomyopathies in mice associated with essentially any sarcomeric gene mutations, but also accurately predicts human cardiac phenotypes from data generated in induced-pluripotent-stem-cell-derived myocytes from familial cardiomyopathy patients. This tension-based model also has the potential to inform pharmacologic treatment options in cardiomyopathy patients.
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Cardiomiopatía Dilatada/metabolismo , Cardiomiopatía Dilatada/patología , Cardiomiopatía Hipertrófica Familiar/metabolismo , Cardiomiopatía Hipertrófica Familiar/patología , Animales , Aorta/patología , Calcineurina/metabolismo , Calcio/metabolismo , Cardiomiopatía Dilatada/genética , Cardiomiopatía Hipertrófica Familiar/genética , Modelos Animales de Enfermedad , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Células Madre Pluripotentes Inducidas/patología , Ratones , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Mutación , Miofibrillas/metabolismoRESUMEN
Translational readthrough, observed primarily in less complex organisms from viruses to Drosophila, expands the proteome by translating select transcripts beyond the canonical stop codon. Here, we show that vascular endothelial growth factor A (VEGFA) mRNA in mammalian endothelial cells undergoes programmed translational readthrough (PTR) generating VEGF-Ax, an isoform containing a unique 22-amino-acid C terminus extension. A cis-acting element in the VEGFA 3' UTR serves a dual function, not only encoding the appended peptide but also directing the PTR by decoding the UGA stop codon as serine. Heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 binds this element and promotes readthrough. Remarkably, VEGF-Ax exhibits antiangiogenic activity in contrast to the proangiogenic activity of VEGF-A. Pathophysiological significance of VEGF-Ax is indicated by robust expression in multiple human tissues but depletion in colon adenocarcinoma. Furthermore, genome-wide analysis revealed AGO1 and MTCH2 as authentic readthrough targets. Overall, our studies reveal a novel protein-regulated PTR event in a vertebrate system.
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Células Endoteliales/metabolismo , Biosíntesis de Proteínas , Factor A de Crecimiento Endotelial Vascular/genética , Regiones no Traducidas 3' , Secuencia de Aminoácidos , Animales , Aorta/citología , Secuencia de Bases , Bovinos , Línea Celular , Codón de Terminación , Células HEK293 , Ribonucleoproteína Heterogénea-Nuclear Grupo A-B/metabolismo , Humanos , Ratones , Datos de Secuencia Molecular , Isoformas de Proteínas/genética , Alineación de SecuenciaRESUMEN
Inflammatory signals support the birth of hematopoietic stem cells in zebrafish embryos, but their cellular source in mammals is not known. In this issue, Mariani et al. (2019) report that macrophages are a primary source of pro-inflammatory signals that promote blood cell formation in mammalian embryos.
Asunto(s)
Trasplante de Células Madre Hematopoyéticas , Suelo , Animales , Aorta , Hematopoyesis , Células Madre Hematopoyéticas , Macrófagos , Pez CebraRESUMEN
Hematopoietic stem cells (HSCs) develop from a specialized subpopulation of endothelial cells known as hemogenic endothelium (HE). Although the HE origin of HSCs is now well established in different species, the signaling pathways that control this transition remain poorly understood. Here, we show that activation of retinoic acid (RA) signaling in aorta-gonad-mesonephros-derived HE ex vivo dramatically enhanced its HSC potential, whereas conditional inactivation of the RA metabolizing enzyme retinal dehydrogenase 2 in VE-cadherin expressing endothelial cells in vivo abrogated HSC development. Wnt signaling completely blocked the HSC inductive effects of RA modulators, whereas inhibition of the pathway promoted the development of HSCs in the absence of RA signaling. Collectively, these findings position RA and Wnt signaling as key regulators of HSC development and in doing so provide molecular insights that will aid in developing strategies for their generation from pluripotent stem cells.
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Células Madre Hematopoyéticas/citología , Tretinoina/metabolismo , Aldehído Oxidorreductasas/metabolismo , Animales , Aorta/citología , Aorta/embriología , Regulación hacia Abajo , Embrión de Mamíferos , Gónadas/citología , Gónadas/embriología , Células Madre Hematopoyéticas/metabolismo , Mesonefro/citología , Ratones , Receptores de Ácido Retinoico/metabolismo , Vía de Señalización WntRESUMEN
Phospholipase Cε (PLCε) is a multifunctional enzyme implicated in cardiovascular, pancreatic, and inflammatory functions. Here we show that conditional deletion of PLCε in mouse cardiac myocytes protects from stress-induced pathological hypertrophy. PLCε small interfering RNA (siRNA) in ventricular myocytes decreases endothelin-1 (ET-1)-dependent elevation of nuclear calcium and activation of nuclear protein kinase D (PKD). PLCε scaffolded to muscle-specific A kinase-anchoring protein (mAKAP), along with PKCε and PKD, localizes these components at or near the nuclear envelope, and this complex is required for nuclear PKD activation. Phosphatidylinositol 4-phosphate (PI4P) is identified as a perinuclear substrate in the Golgi apparatus for mAKAP-scaffolded PLCε. We conclude that perinuclear PLCε, scaffolded to mAKAP in cardiac myocytes, responds to hypertrophic stimuli to generate diacylglycerol (DAG) from PI4P in the Golgi apparatus, in close proximity to the nuclear envelope, to regulate activation of nuclear PKD and hypertrophic signaling pathways.
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Cardiomegalia/metabolismo , Cardiomegalia/patología , Fosfatos de Fosfatidilinositol/metabolismo , Fosfoinositido Fosfolipasa C/metabolismo , Animales , Aorta/patología , Subunidades alfa de la Proteína de Unión al GTP Gq-G11/metabolismo , Aparato de Golgi/metabolismo , Corazón , Ventrículos Cardíacos/citología , Masculino , Ratones , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Membrana Nuclear/metabolismo , Fosfoinositido Fosfolipasa C/genética , Ratas , Transducción de SeñalRESUMEN
The maintenance of appropriate arterial tone is critically important for normal physiological arterial function. However, the cellular and molecular mechanisms remain poorly defined. Here, we have shown that in the mouse aorta, resident macrophages prevented arterial stiffness and collagen deposition in the steady state. Using phenotyping, transcriptional profiling, and targeted deletion of Csf1r, we have demonstrated that these macrophages-which are a feature of blood vessels invested with smooth muscle cells (SMCs) in both mouse and human tissues-expressed the hyaluronan (HA) receptor LYVE-l. Furthermore, we have shown they possessed the unique ability to modulate collagen expression in SMCs by matrix metalloproteinase MMP-9-dependent proteolysis through engagement of LYVE-1 with the HA pericellular matrix of SMCs. Our study has unveiled a hitherto unknown homeostatic contribution of arterial LYVE-1+ macrophages through the control of collagen production by SMCs and has identified a function of LYVE-1 in leukocytes.
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Colágeno/metabolismo , Glicoproteínas/metabolismo , Receptores de Hialuranos/metabolismo , Macrófagos/metabolismo , Músculo Liso Vascular/citología , Miocitos del Músculo Liso/metabolismo , Rigidez Vascular/fisiología , Animales , Aorta/fisiología , Femenino , Glicoproteínas/genética , Humanos , Ácido Hialurónico/metabolismo , Masculino , Metaloproteinasa 9 de la Matriz/metabolismo , Proteínas de Transporte de Membrana , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores de Factor Estimulante de Colonias de Granulocitos y Macrófagos/genéticaRESUMEN
Hutchinson-Gilford progeria syndrome (HGPS or progeria) is typically caused by a dominant-negative Câ¢G-to-Tâ¢A mutation (c.1824 C>T; p.G608G) in LMNA, the gene that encodes nuclear lamin A. This mutation causes RNA mis-splicing that produces progerin, a toxic protein that induces rapid ageing and shortens the lifespan of children with progeria to approximately 14 years1-4. Adenine base editors (ABEs) convert targeted Aâ¢T base pairs to Gâ¢C base pairs with minimal by-products and without requiring double-strand DNA breaks or donor DNA templates5,6. Here we describe the use of an ABE to directly correct the pathogenic HGPS mutation in cultured fibroblasts derived from children with progeria and in a mouse model of HGPS. Lentiviral delivery of the ABE to fibroblasts from children with HGPS resulted in 87-91% correction of the pathogenic allele, mitigation of RNA mis-splicing, reduced levels of progerin and correction of nuclear abnormalities. Unbiased off-target DNA and RNA editing analysis did not detect off-target editing in treated patient-derived fibroblasts. In transgenic mice that are homozygous for the human LMNA c.1824 C>T allele, a single retro-orbital injection of adeno-associated virus 9 (AAV9) encoding the ABE resulted in substantial, durable correction of the pathogenic mutation (around 20-60% across various organs six months after injection), restoration of normal RNA splicing and reduction of progerin protein levels. In vivo base editing rescued the vascular pathology of the mice, preserving vascular smooth muscle cell counts and preventing adventitial fibrosis. A single injection of ABE-expressing AAV9 at postnatal day 14 improved vitality and greatly extended the median lifespan of the mice from 215 to 510 days. These findings demonstrate the potential of in vivo base editing as a possible treatment for HGPS and other genetic diseases by directly correcting their root cause.
Asunto(s)
Adenina/metabolismo , Edición Génica/métodos , Mutación , Progeria/genética , Progeria/terapia , Alelos , Empalme Alternativo , Animales , Aorta/patología , Emparejamiento Base , Niño , ADN/genética , Modelos Animales de Enfermedad , Femenino , Fibroblastos/metabolismo , Humanos , Lamina Tipo A/química , Lamina Tipo A/genética , Lamina Tipo A/metabolismo , Longevidad , Masculino , Ratones , Ratones Transgénicos , Proteínas Mutantes/química , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Progeria/patología , ARN/genéticaRESUMEN
Recent studies have highlighted the crucial role of the aorta microenvironment in the generation of the first haematopoietic stem cells (HSCs) from specialized haemogenic endothelial cells (HECs). Despite more than two decades of investigations, we require a better understanding of the cellular and molecular events driving aorta formation and polarization, which will be pivotal to establish the mechanisms that operate during HEC specification and HSC competency. Here, we outline the early mechanisms involved in vertebrate aorta formation by comparing four different species: zebrafish, chicken, mouse and human. We highlight how this process, which is tightly controlled in time and space, requires a coordinated specification of several cell types, in particular endothelial cells originating from distinct mesodermal tissues. We also discuss how molecular signals originating from the aorta environment result in its polarization, creating a unique entity for HSC generation.
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Hemangioblastos , Pez Cebra , Animales , Humanos , Ratones , Pez Cebra/metabolismo , Células Madre Hematopoyéticas/metabolismo , Hemangioblastos/metabolismo , Proteínas de Pez Cebra/metabolismo , Aorta , Diferenciación Celular , HematopoyesisRESUMEN
The emergence of definitive human haematopoietic stem cells (HSCs) from Carnegie Stage (CS) 14 to CS17 in the aorta-gonad-mesonephros (AGM) region is a tightly regulated process. Previously, we conducted spatial transcriptomic analysis of the human AGM region at the end of this period (CS16/CS17) and identified secreted factors involved in HSC development. Here, we extend our analysis to investigate the progression of dorso-ventral polarised signalling around the dorsal aorta over the entire period of HSC emergence. Our results reveal a dramatic increase in ventral signalling complexity from the CS13-CS14 transition, coinciding with the first appearance of definitive HSCs. We further observe stage-specific changes in signalling up to CS17, which may underpin the step-wise maturation of HSCs described in the mouse model. The data-rich resource is also presented in an online interface enabling in silico analysis of molecular interactions between spatially defined domains of the AGM region. This resource will be of particular interest for researchers studying mechanisms underlying human HSC development as well as those developing in vitro methods for the generation of clinically relevant HSCs from pluripotent stem cells.
Asunto(s)
Células Madre Hematopoyéticas , Transducción de Señal , Ratones , Animales , Humanos , Transducción de Señal/genética , Comunicación Celular , Perfilación de la Expresión Génica , Aorta , Mesonefro , Gónadas , Hematopoyesis/genéticaRESUMEN
BACKGROUND: Endothelial cell (EC) generation and turnover by self-proliferation contributes to vascular repair and regeneration. The ability to accurately measure the dynamics of EC generation would advance our understanding of cellular mechanisms of vascular homeostasis and diseases. However, it is currently challenging to evaluate the dynamics of EC generation in large vessels such as arteries because of their infrequent proliferation. METHODS: By using dual recombination systems based on Cre-loxP and Dre-rox, we developed a genetic system for temporally seamless recording of EC proliferation in vivo. We combined genetic recording of EC proliferation with single-cell RNA sequencing and gene knockout to uncover cellular and molecular mechanisms underlying EC generation in arteries during homeostasis and disease. RESULTS: Genetic proliferation tracing reveals that ≈3% of aortic ECs undergo proliferation per month in adult mice during homeostasis. The orientation of aortic EC division is generally parallel to blood flow in the aorta, which is regulated by the mechanosensing protein Piezo1. Single-cell RNA sequencing analysis reveals 4 heterogeneous aortic EC subpopulations with distinct proliferative activity. EC cluster 1 exhibits transit-amplifying cell features with preferential proliferative capacity and enriched expression of stem cell markers such as Sca1 and Sox18. EC proliferation increases in hypertension but decreases in type 2 diabetes, coinciding with changes in the extent of EC cluster 1 proliferation. Combined gene knockout and proliferation tracing reveals that Hippo/vascular endothelial growth factor receptor 2 signaling pathways regulate EC proliferation in large vessels. CONCLUSIONS: Genetic proliferation tracing quantitatively delineates the dynamics of EC generation and turnover, as well as EC division orientation, in large vessels during homeostasis and disease. An EC subpopulation in the aorta exhibits more robust cell proliferation during homeostasis and type 2 diabetes, identifying it as a potential therapeutic target for vascular repair and regeneration.
Asunto(s)
Diabetes Mellitus Tipo 2 , Factor A de Crecimiento Endotelial Vascular , Animales , Ratones , Factor A de Crecimiento Endotelial Vascular/metabolismo , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Aorta/metabolismo , Células Endoteliales/metabolismo , Homeostasis , Canales Iónicos/metabolismoRESUMEN
BACKGROUND: Ascending aorta dilation and aortic valve degeneration are common complications in patients with bicuspid aortic valve. Several retrospective studies have suggested the benefit of statins in reducing these complications. This study aimed to determine whether atorvastatin treatment is effective in reducing the growth of aortic diameters in bicuspid aortic valve and if it slows the progression of valve calcification. METHODS: In a randomized clinical trial, 220 patients with bicuspid aortic valve (43 women; 46±13 years of age) were included and treated with either 20 mg of atorvastatin per day or placebo for 3 years. Inclusion criteria were ≥18 years of age, nonsevere valvular dysfunction, nonsevere valve calcification, and ascending aorta diameter ≤50 mm. Computed tomography and echocardiography studies were performed at baseline and after 3 years of treatment. RESULTS: During follow-up, 28 patients (12.7%) discontinued medical treatment (15 on atorvastatin and 13 taking placebo). Thus, 192 patients completed the 36 months of treatment. Low-density lipoprotein cholesterol levels decreased significantly in the atorvastatin group (median [interquartile range], -30 mg/dL [-51.65 to -1.75 mg/dL] versus 6 mg/dL [-4, 22.5 mg/dL]; P<0.001). The maximum ascending aorta diameter increased with no differences between groups: 0.65 mm (95% CI, 0.45-0.85) in the atorvastatin group and 0.74 mm (95% CI, 0.45-1.04) in the placebo group (P=0.613). Similarly, no significant differences were found for the progression of the aortic valve calcium score (P=0.167) or valvular dysfunction. CONCLUSIONS: Among patients with bicuspid aortic valve without severe valvular dysfunction, atorvastatin treatment was not effective in reducing the progression of ascending aorta dilation and aortic valve calcification during 3 years of treatment despite a significant reduction in low-density lipoprotein cholesterol levels. REGISTRATION: URL: https://www.clinicaltrialsregister.eu; Unique identifier: 2015-001808-57. URL: https://www.clinicaltrials.gov; Unique identifier: NCT02679261.
Asunto(s)
Válvula Aórtica , Atorvastatina , Enfermedad de la Válvula Aórtica Bicúspide , Calcinosis , Progresión de la Enfermedad , Enfermedades de las Válvulas Cardíacas , Inhibidores de Hidroximetilglutaril-CoA Reductasas , Humanos , Atorvastatina/uso terapéutico , Femenino , Masculino , Persona de Mediana Edad , Válvula Aórtica/diagnóstico por imagen , Válvula Aórtica/patología , Válvula Aórtica/anomalías , Válvula Aórtica/efectos de los fármacos , Calcinosis/tratamiento farmacológico , Calcinosis/diagnóstico por imagen , Calcinosis/patología , Enfermedad de la Válvula Aórtica Bicúspide/diagnóstico por imagen , Enfermedad de la Válvula Aórtica Bicúspide/tratamiento farmacológico , Enfermedades de las Válvulas Cardíacas/tratamiento farmacológico , Enfermedades de las Válvulas Cardíacas/diagnóstico por imagen , Enfermedades de las Válvulas Cardíacas/patología , Adulto , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Dilatación Patológica/tratamiento farmacológico , Estudios de Seguimiento , Método Doble Ciego , Resultado del Tratamiento , Aorta/diagnóstico por imagen , Aorta/patología , Aorta/efectos de los fármacos , Enfermedad de la Válvula Aórtica/tratamiento farmacológico , Estenosis de la Válvula AórticaRESUMEN
Hematopoietic stem and progenitor cells (HSPCs) are multipotent cells that self-renew or differentiate to establish the entire blood hierarchy. HSPCs arise from the hemogenic endothelium of the dorsal aorta (DA) during development in a process called endothelial-to-hematopoietic transition. The factors and signals that control HSPC fate decisions from the hemogenic endothelium are not fully understood. We found that Vegfc has a role in HSPC emergence from the zebrafish DA. Using time-lapse live imaging, we show that some HSPCs in the DA of vegfc loss-of-function embryos display altered cellular behavior. Instead of typical budding from the DA, emergent HSPCs exhibit crawling behavior similar to myeloid cells. This was confirmed by increased myeloid cell marker expression in the ventral wall of the DA and the caudal hematopoietic tissue. This increase in myeloid cells corresponded with a decrease in HSPCs that persisted into larval stages. Together, our data suggest that Vegfc regulates HSPC emergence in the hemogenic endothelium, in part by suppressing a myeloid cell fate. Our study provides a potential signal for modulation of HSPC fate in stem cell differentiation protocols.
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Aorta/citología , Diferenciación Celular , Células Madre Hematopoyéticas/metabolismo , Factor C de Crecimiento Endotelial Vascular/metabolismo , Proteínas de Pez Cebra/metabolismo , Animales , Aorta/embriología , Células Cultivadas , Endotelio Vascular/citología , Endotelio Vascular/embriología , Células Madre Hematopoyéticas/citología , Mutación con Pérdida de Función , Células Mieloides/citología , Células Mieloides/metabolismo , Factor C de Crecimiento Endotelial Vascular/genética , Pez Cebra , Proteínas de Pez Cebra/genéticaRESUMEN
The human cardiovascular system has evolved to accommodate the gravity of Earth. Microgravity during spaceflight has been shown to induce vascular remodeling, leading to a decline in vascular function. The underlying mechanisms are not yet fully understood. Our previous study demonstrated that miR-214 plays a critical role in angiotensin II-induced vascular remodeling by reducing the levels of Smad7 and increasing the phosphorylation of Smad3. However, its role in vascular remodeling evoked by microgravity is not yet known. This study aimed to determine the contribution of miR-214 to the regulation of microgravity-induced vascular remodeling. The results of our study revealed that miR-214 expression was increased in the forebody arteries of both mice and monkeys after simulated microgravity treatment. In vitro, rotation-simulated microgravity-induced VSMC migration, hypertrophy, fibrosis, and inflammation were repressed by miR-214 knockout (KO) in VSMCs. Additionally, miR-214 KO increased the level of Smad7 and decreased the phosphorylation of Smad3, leading to a decrease in downstream gene expression. Furthermore, miR-214 cKO protected against simulated microgravity induced the decline in aorta function and the increase in stiffness. Histological analysis showed that miR-214 cKO inhibited the increases in vascular medial thickness that occurred after simulated microgravity treatment. Altogether, these results demonstrate that miR-214 has potential as a therapeutic target for the treatment of vascular remodeling caused by simulated microgravity.
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MicroARNs , Ingravidez , Humanos , Ratones , Animales , Músculo Liso Vascular/metabolismo , MicroARNs/metabolismo , Remodelación Vascular/genética , Aorta/metabolismo , Miocitos del Músculo Liso/metabolismoRESUMEN
BACKGROUND: Giant cell arteritis (GCA) causes severe inflammation of the aorta and its branches and is characterized by intense effector T-cell infiltration. The roles that immune checkpoints play in the pathogenesis of GCA are still unclear. Our aim was to study the immune checkpoint interplay in GCA. METHODS: First, we used VigiBase, the World Health Organization international pharmacovigilance database, to evaluate the relationship between GCA occurrence and immune checkpoint inhibitors treatments. We then further dissected the role of immune checkpoint inhibitors in the pathogenesis of GCA, using immunohistochemistry, immunofluorescence, transcriptomics, and flow cytometry on peripheral blood mononuclear cells and aortic tissues of GCA patients and appropriated controls. RESULTS: Using VigiBase, we identified GCA as a significant immune-related adverse event associated with anti-CTLA-4 (cytotoxic T-lymphocyte-associated protein-4) but not anti-PD-1 (anti-programmed death-1) nor anti-PD-L1 (anti-programmed death-ligand 1) treatment. We further dissected a critical role for the CTLA-4 pathway in GCA by identification of the dysregulation of CTLA-4-derived gene pathways and proteins in CD4+ (cluster of differentiation 4) T cells (and specifically regulatory T cells) present in blood and aorta of GCA patients versus controls. While regulatory T cells were less abundant and activated/suppressive in blood and aorta of GCA versus controls, they still specifically upregulated CTLA-4. Activated and proliferating CTLA-4+ Ki-67+ regulatory T cells from GCA were more sensitive to anti-CTLA-4 (ipilimumab)-mediated in vitro depletion versus controls. CONCLUSIONS: We highlighted the instrumental role of CTLA-4 immune checkpoint in GCA, which provides a strong rationale for targeting this pathway.
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Antígeno CTLA-4 , Arteritis de Células Gigantes , Humanos , Aorta , Inhibidores de Puntos de Control Inmunológico , Leucocitos Mononucleares , Linfocitos T Reguladores , Antígeno CTLA-4/metabolismoRESUMEN
Clinical imaging modalities are a mainstay of modern disease management, but the full utilization of imaging-based data remains elusive. Aortic disease is defined by anatomic scalars quantifying aortic size, even though aortic disease progression initiates complex shape changes. We present an imaging-based geometric descriptor, inspired by fundamental ideas from topology and soft-matter physics that captures dynamic shape evolution. The aorta is reduced to a two-dimensional mathematical surface in space whose geometry is fully characterized by the local principal curvatures. Disease causes deviation from the smooth bent cylindrical shape of normal aortas, leading to a family of highly heterogeneous surfaces of varying shapes and sizes. To deconvolute changes in shape from size, the shape is characterized using integrated Gaussian curvature or total curvature. The fluctuation in total curvature (δK) across aortic surfaces captures heterogeneous morphologic evolution by characterizing local shape changes. We discover that aortic morphology evolves with a power-law defined behavior with rapidly increasing δK forming the hallmark of aortic disease. Divergent δK is seen for highly diseased aortas indicative of impending topologic catastrophe or aortic rupture. We also show that aortic size (surface area or enclosed aortic volume) scales as a generalized cylinder for all shapes. Classification accuracy for predicting aortic disease state (normal, diseased with successful surgery, and diseased with failed surgical outcomes) is 92.8±1.7%. The analysis of δK can be applied on any three-dimensional geometric structure and thus may be extended to other clinical problems of characterizing disease through captured anatomic changes.
Asunto(s)
Aorta , Disección Aórtica , Humanos , Aorta/diagnóstico por imagen , Aorta/cirugía , Disección Aórtica/diagnóstico por imagen , Disección Aórtica/cirugíaRESUMEN
BACKGROUND: RAB27A is a member of the RAS oncogene superfamily of GTPases and regulates cell secretory function. It, is expressed within blood vessels and perivascular adipose tissue. We hypothesized that loss of RAB27A would alter cardiovascular function. METHODS: Body weight of Rab27aash mice was measured from 2 to 18 months of age, along with glucose resorption at 6 and 12 months of age and glucose sensitivity at 18 months of age. Body weight and cellular and molecular features of perivascular adipose tissue and aortic tissue were examined in a novel C57BL/6J Rab27a null strain. Analyses included morphometric quantification and proteomic analyses. Wire myography measured vasoreactivity, and echocardiography measured cardiac function. Comparisons across ages and genotypes were evaluated via 2-way ANOVA with multiple comparison testing. Significance for myography was determined via 4-parameter nonlinear regression testing. RESULTS: Genome-wide association data linked rare human RAB27A variants with body mass index and glucose handling. Changes in glucose tolerance were observed in Rab27aash male mice at 18 months of age. In WT (wild-type) and Rab27a null male mice, body weight, adipocyte lipid area, and aortic area increased with age. In female mice, only body weight increased with age, independent of RAB27A presence. Protein signatures from male Rab27a null mice suggested greater associations with cardiovascular and metabolic phenotypes compared with female tissues. Wire myography results showed Rab27a null males exhibited increased vasoconstriction and reduced vasodilation at 8 weeks of age. Rab27a null females exhibited increased vasoconstriction and vasodilation at 20 weeks of age. Consistent with these vascular changes, male Rab27a null mice experienced age-related cardiomyopathy, with severe differences observed by 21 weeks of age. CONCLUSIONS: Global RAB27A loss impacted perivascular adipose tissue and thoracic aorta proteomic signatures, altered vasocontractile responses, and decreased left ventricular ejection fraction in mice.
Asunto(s)
Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas rab27 de Unión a GTP , Animales , Proteínas rab27 de Unión a GTP/genética , Proteínas rab27 de Unión a GTP/metabolismo , Masculino , Femenino , Ratones , Fenotipo , Tejido Adiposo/metabolismo , Vasodilatación , Vasoconstricción , Factores de Edad , Proteómica , Factores Sexuales , Aorta/metabolismo , Aorta/fisiopatología , HumanosRESUMEN
BACKGROUND: Smooth muscle cells (SMCs), which make up the medial layer of arteries, are key cell types involved in cardiovascular disease, the leading cause of mortality and morbidity worldwide. In response to microenvironment alterations, SMCs dedifferentiate from a contractile to a synthetic phenotype characterized by an increased proliferation, migration, production of ECM (extracellular matrix) components, and decreased expression of SMC-specific contractile markers. These phenotypic changes result in vascular remodeling and contribute to the pathogenesis of cardiovascular disease, including coronary artery disease, stroke, hypertension, and aortic aneurysms. Here, we aim to identify the genetic variants that regulate ECM secretion in SMCs and predict the causal proteins associated with vascular disease-related loci identified in genome-wide association studies. METHODS: Using human aortic SMCs from 123 multiancestry healthy heart transplant donors, we collected the serum-free media in which the cells were cultured for 24 hours and conducted liquid chromatography-tandem mass spectrometry-based proteomic analysis of the conditioned media. RESULTS: We measured the abundance of 270 ECM and related proteins. Next, we performed protein quantitative trait locus mapping and identified 20 loci associated with secreted protein abundance in SMCs. We functionally annotated these loci using a colocalization approach. This approach prioritized the genetic variant rs6739323-A at the 2p22.3 locus, which is associated with lower expression of LTBP1 (latent-transforming growth factor beta-binding protein 1) in SMCs and atherosclerosis-prone areas of the aorta, and increased risk for SMC calcification. We found that LTBP1 expression is abundant in SMCs, and its expression at mRNA and protein levels was reduced in unstable and advanced atherosclerotic plaque lesions. CONCLUSIONS: Our results unravel the SMC proteome signature associated with vascular disorders, which may help identify potential therapeutic targets to accelerate the pathway to translation.
Asunto(s)
Aterosclerosis , Enfermedades Cardiovasculares , Humanos , Enfermedades Cardiovasculares/metabolismo , Estudio de Asociación del Genoma Completo , Proteómica , Músculo Liso Vascular/metabolismo , Aorta/metabolismo , Aterosclerosis/patología , Miocitos del Músculo Liso/metabolismo , Células CultivadasRESUMEN
BACKGROUND: The metabolic alterations occurring within the arterial architecture during atherosclerosis development remain poorly understood, let alone those particular to each arterial tunica. We aimed first to identify, in a spatially resolved manner, the specific metabolic changes in plaque, media, adventitia, and cardiac tissue between control and atherosclerotic murine aortas. Second, we assessed their translatability to human tissue and plasma for cardiovascular risk estimation. METHODS: In this observational study, mass spectrometry imaging (MSI) was applied to identify region-specific metabolic differences between atherosclerotic (n=11) and control (n=11) aortas from low-density lipoprotein receptor-deficient mice, via histology-guided virtual microdissection. Early and advanced plaques were compared within the same atherosclerotic animals. Progression metabolites were further analyzed by MSI in 9 human atherosclerotic carotids and by targeted mass spectrometry in human plasma from subjects with elective coronary artery bypass grafting (cardiovascular risk group, n=27) and a control group (n=27). RESULTS: MSI identified 362 local metabolic alterations in atherosclerotic mice (log2 fold-change ≥1.5; P≤0.05). The lipid composition of cardiac tissue is altered during atherosclerosis development and presents a generalized accumulation of glycerophospholipids, except for lysolipids. Lysolipids (among other glycerophospholipids) were found at elevated levels in all 3 arterial layers of atherosclerotic aortas. LPC(18:0) (lysophosphatidylcholine; P=0.024) and LPA(18:1) (lysophosphatidic acid; P=0.025) were found to be significantly elevated in advanced plaques as compared with mouse-matched early plaques. Higher levels of both lipid species were also observed in fibrosis-rich areas of advanced- versus early-stage human samples. They were found to be significantly reduced in human plasma from subjects with elective coronary artery bypass grafting (P<0.001 and P=0.031, respectively), with LPC(18:0) showing significant association with cardiovascular risk (odds ratio, 0.479 [95% CI, 0.225-0.883]; P=0.032) and diagnostic potential (area under the curve, 0.778 [95% CI, 0.638-0.917]). CONCLUSIONS: An altered phospholipid metabolism occurs in atherosclerosis, affecting both the aorta and the adjacent heart tissue. Plaque-progression lipids LPC(18:0) and LPA(18:1), as identified by MSI on tissue, reflect cardiovascular risk in human plasma.
Asunto(s)
Enfermedades de la Aorta , Aterosclerosis , Enfermedades Cardiovasculares , Placa Aterosclerótica , Humanos , Animales , Ratones , Placa Aterosclerótica/metabolismo , Enfermedades Cardiovasculares/diagnóstico , Enfermedades Cardiovasculares/metabolismo , Factores de Riesgo , Aterosclerosis/diagnóstico , Aterosclerosis/metabolismo , Aorta/diagnóstico por imagen , Aorta/metabolismo , Enfermedades de la Aorta/genética , Enfermedades de la Aorta/metabolismo , Glicerofosfolípidos/metabolismo , Factores de Riesgo de Enfermedad CardiacaRESUMEN
BACKGROUND: Atherosclerosis is driven by the infiltration of the arterial intima by diverse immune cells and smooth muscle cells (SMCs). CD8+ T cells promote lesion growth during atherosclerotic lesion development, but their role in advanced atherosclerosis is less clear. Here, we studied the role of CD8+ T cells and their effects on SMCs in established atherosclerosis. METHODS: CD8+ T cells were depleted in (SMC reporter) low-density lipoprotein receptor-deficient (Ldlr-/-) mice with established atherosclerotic lesions. Atherosclerotic lesion formation was examined, and single-cell RNA sequencing of aortic SMCs and their progeny was performed. Additionally, coculture experiments with primary aortic SMCs and CD8+ T cells were conducted. RESULTS: Although we could not detect differences in atherosclerotic lesion size, an increased plaque SMC content was noted in mice after CD8+ T-cell depletion. Single-cell RNA sequencing of aortic lineage-traced SMCs revealed contractile SMCs and a modulated SMC cluster, expressing macrophage- and osteoblast-related genes. CD8+ T-cell depletion was associated with an increased contractile but decreased macrophage and osteoblast-like gene signature in this modulated aortic SMC cluster. Conversely, exposure of isolated aortic SMCs to activated CD8+ T cells decreased the expression of genes indicative of a contractile SMC phenotype and induced a macrophage and osteoblast-like cell state. Notably, CD8+ T cells triggered calcium deposits in SMCs under osteogenic conditions. Mechanistically, we identified transcription factors highly expressed in modulated SMCs, including Runx1, to be induced by CD8+ T cells in cultured SMCs in an IFNγ (interferon-γ)-dependent manner. CONCLUSIONS: We here uncovered CD8+ T cells to control the SMC phenotype in atherosclerosis. CD8+ T cells promote SMC dedifferentiation and drive SMCs to adopt features of macrophage-like and osteoblast-like, procalcifying cell phenotypes. Given the critical role of SMCs in atherosclerotic plaque stability, CD8+ T cells could thus be explored as therapeutic target cells during lesion progression.