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1.
Clin Appl Thromb Hemost ; 27: 10760296211044723, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34609920

RESUMO

BACKGROUND: An antiplatelet therapy with acetylsalicylic acid (ASA) is prescribed in the prevention of cardiovascular events, but around 24% of ASA takers are resistant to the treatment. AIM: In this prospective, observational cohort study, we aimed to identify the prevalence and risk factors of ASA nonresponse in patients who underwent vascular surgery. METHODS: The study was conducted in the University hospital in Frankfurt am Main. In total, 70 patients were pre-treated with 100 mg of ASA per day and underwent either elective carotid thromboendarterectomy, femoral thromboendarterectomy or endovascular aneurysm repair of the abdominal aorta. The platelet function was measured on the first preoperative and the second or fourth postoperative day with the multiple electrode aggregometry by in-vitro stimulation with arachidonic acid (ASPItest) and thrombin receptor activating peptide 6 (TRAPtest). The primary end point was the in-vitro induced platelet aggregation in the ASPItest. If the ASPItest amounted ≥400 AU × min, the patients were categorized as ASA nonresponders. RESULTS: The total prevalence of ASA nonresponse in our study was 20% preoperatively and 35.7% postoperatively (p = 0.005). As significant predictors for ASA nonresponse, we demonstrated the area under the aggregation curve in the TRAPtest preoperatively (p = 0.04) and postoperatively (p = 0.02), and the two comorbidities arterial hypertension (P < .001; rho 0.44) and diabetes mellitus (p = 0.04; rho 0.39), which are already well known to be associated with ASA nonresponse. CONCLUSION: In conclusion, data of the study indicate a high incidence of perioperative, laboratory ASA nonresponse in patients undergoing vascular surgery.

2.
Artigo em Inglês | MEDLINE | ID: mdl-34609521

RESUMO

PURPOSE: To determine whether internal fixation (IF) or hip arthroplasty (HA) is associated with superior outcomes in geriatric nondisplaced femoral neck fracture (FNF) patients. METHODS: Data from the Registry for Geriatric Trauma of the German Trauma Society (ATR-DGU) were analyzed (IF Group 449 and HA Group 1278 patients). In-hospital care and a 120-day postoperative follow-up were conducted. Primary outcomes, including mobility, residential status, reoperation rate, and a generic health status measure (EQ-5D score), and the secondary outcome of mortality were compared between groups. Multivariable analyses were performed to assess independent treatment group associations (odds ratios, ORs) with the primary and secondary end points. RESULTS: Patients in the HA group were older (83 vs. 81 years, p < 0.001) and scored higher on the Identification of Seniors at Risk screening (3 vs. 2, p < 0.001). We observed no differences in residential status, reoperation rate, EQ-5D score, or mortality between groups. After adjusting for key covariates, including prefracture ambulatory capacity, the mobility of patients in the HA group was more frequently impaired at the 120-day follow-up (OR 2.28, 95% confidence interval = 1.11-4.74). CONCLUSION: Treatment with HA compared to treatment with IF led to a more than twofold increase in the adjusted odds of impaired ambulation at the short-term follow-up, while no significant associations with residential status, reoperation rate, EQ-5D index score, or mortality were observed. Thus, IF for geriatric nondisplaced FNFs was associated with superior mobility 120 days after surgery. However, before definitive treatment recommendations can be made, prospective, randomized, long-term studies must be performed to confirm our findings.

3.
Front Cardiovasc Med ; 8: 749022, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34631841

RESUMO

Background: Bruton tyrosine kinase inhibitors (BTKi) are used in B-cell malignancies and in development against various autoimmune diseases. Since Btk is also involved in specific pathways of platelet activation, BTKi might be considered to target platelet GPVI/GPIb-mediated atherothrombosis and platelet FcγRIIA-dependent immune disorders. However, BTKi treatment of patients with B-cell malignancies is frequently associated with mild bleeding events caused possibly by off-target inhibition of Tec. Here, we compared the platelet effects of two novel BTKi that exhibit a high (remibrutinib) or low (rilzabrutinib) selectivity for Btk over Tec. Methods and Results: Remibrutinib and rilzabrutinib were pre-incubated with anticoagulated blood. Platelet aggregation and in vitro bleeding time (closure time) were studied by multiple electrode aggregometry (MEA) and platelet-function analyzer-200 (PFA-200), respectively. Both BTKi inhibited atherosclerotic plaque-stimulated GPVI-mediated platelet aggregation, remibrutinib being more potent (IC50 = 0.03 µM) than rilzabrutinib (IC50 = 0.16 µM). Concentrations of remibrutinib (0.1 µM) and rilzabrutinib (0.5 µM), >80% inhibitory for plaque-induced aggregation, also significantly suppressed (>90%) the Btk-dependent pathways of platelet aggregation upon GPVI, von Willebrand factor/GPIb and FcγRIIA activation stimulated by low collagen concentrations, ristocetin and antibody cross-linking, respectively. Both BTKi did not inhibit aggregation stimulated by ADP, TRAP-6 or arachidonic acid. Remibrutinib (0.1 µM) only slightly prolonged closure time and significantly less than rilzabrutinib (0.5 µM). Conclusion: Remibrutinib and rilzabrutinib inhibit Btk-dependent pathways of platelet aggregation upon GPVI, VWF/GPIb, and FcγRIIA activation. Remibrutinib being more potent and showing a better profile of inhibition of Btk-dependent platelet activation vs. hemostatic impairment than rilzabrutinib may be considered for further development as an antiplatelet drug.

5.
Clin Lab ; 67(8)2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34383400

RESUMO

BACKGROUND: Acquired platelet dysfunction is a common element of trauma-induced coagulopathy and has been linked to increased mortality. The aim of the study was to describe the prevalence of platelet dysfunction in patients with acute intracranial bleeding. METHODS: Patients diagnosed with acute intracranial bleeding were screened for eligibility. Patients with an urgent need for craniotomy were enrolled in this prospective monocentric study. Platelet function analyses using multiple electrode aggregometry (TRAPtest, ASPItest and ADPtest) and conventional coagulation tests were performed. The area under the aggregation curves of the ASPItest and ADPtest were defined as primary outcome variables. RESULTS: Seventy-seven patients were screened for eligibility, and 49 patients were ultimately enrolled in the study. In 14 patients (29%), clinically relevant platelet dysfunction was observed. Of those, 8 patients were treated with antiaggregatory medication at the time of study inclusion. Six patients (12%) were diagnosed with acute acquired platelet dysfunction. CONCLUSIONS: Decreased platelet function was present in nearly one-third of patients with acute intracranial bleeding. Hemotherapy algorithms for the treatment of coagulopathy in this cohort should incorporate aggregometric measures to enable rapid goal-directed therapy.


Assuntos
Agregação Plaquetária , Testes de Função Plaquetária , Humanos , Hemorragias Intracranianas/diagnóstico , Hemorragia Pós-Operatória , Estudos Prospectivos
6.
BMC Genom Data ; 22(1): 23, 2021 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-34193044

RESUMO

BACKGROUND: MicroRNAs (miRNAs) are short (20-24 nt) non-coding RNAs that are involved in post-transcriptional regulation of gene expression in multicellular organisms by affecting both the stability and translation of mRNAs. One of the miRNAs that has been shown to play a role in various pathologies like cancer, neurological disorders and cardiovascular diseases is miRNA-26b. However, these studies only demonstrated rather ambiguous associations without revealing a causal relationship. Therefore, the aim of this study is to establish and validate a mouse model which enables the elucidation of the exact role of miRNA-26b in various pathologies. RESULTS: A miRNA-26b-deficient mouse model was established using homologous recombination and validated using PCR. miRNA-26b-deficient mice did not show any physiological abnormalities and no effects on systemic lipid levels, blood parameters or tissue leukocytes. Using next generation sequencing, the gene expression patterns in miRNA-26b-deficient mice were analyzed and compared to wild type controls. This supported the already suggested role of miRNA-26b in cancer and neurological processes, but also revealed novel associations of miRNA-26b with thermogenesis and allergic reactions. In addition, detailed analysis identified several genes that seem to be highly regulated by miRNA-26b, which are linked to the same pathological conditions, further confirming the role of miRNA-26b in these pathologies and providing a strong validation of our mouse model. CONCLUSIONS: miRNA-26b plays an important role in various pathologies, although causal relationships still have to be established. The described mouse model of miRNA-26b deficiency is a crucial first step towards the identification of the exact role of miRNA-26b in various diseases that could identify miRNA-26b as a promising novel diagnostic or even therapeutic target in a broad range of pathologies.

7.
Circulation ; 144(13): 1059-1073, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34233454

RESUMO

BACKGROUND: The necrotic core partly formed by ineffective efferocytosis increases the risk of an atherosclerotic plaque rupture. Microribonucleic acids contribute to necrotic core formation by regulating efferocytosis and macrophage apoptosis. Atherosclerotic plaque rupture occurs at increased frequency in the early morning, indicating diurnal changes in plaque vulnerability. Although circadian rhythms play a role in atherosclerosis, the molecular clock output pathways that control plaque composition and rupture susceptibility are unclear. METHODS: Circadian gene expression, necrotic core size, apoptosis, and efferocytosis in aortic lesions were investigated at different times of the day in Apoe-/-Mir21+/+ mice and Apoe-/-Mir21-/- mice after consumption of a high-fat diet for 12 weeks. Genome-wide gene expression and lesion formation were analyzed in bone marrow-transplanted mice. Diurnal changes in apoptosis and clock gene expression were determined in human atherosclerotic lesions. RESULTS: The expression of molecular clock genes, lesional apoptosis, and necrotic core size were diurnally regulated in Apoe-/- mice. Efferocytosis did not match the diurnal increase in apoptosis at the beginning of the active phase. However, in parallel with apoptosis, expression levels of oscillating Mir21 strands decreased in the mouse atherosclerotic aorta. Mir21 knockout abolished circadian regulation of apoptosis and reduced necrotic core size but did not affect core clock gene expression. Further, Mir21 knockout upregulated expression of proapoptotic Xaf1 (XIAP-associated factor 1) in the atherosclerotic aorta, which abolished circadian expression of Xaf1. The antiapoptotic effect of Mir21 was mediated by noncanonical targeting of Xaf1 through both Mir21 strands. Mir21 knockout in bone marrow cells also reduced atherosclerosis and necrotic core size. Circadian regulation of clock gene expression was confirmed in human atherosclerotic lesions. Apoptosis oscillated diurnally in phase with XAF1 expression, demonstrating an early morning peak antiphase to that of the Mir21 strands. CONCLUSIONS: Our findings suggest that the molecular clock in atherosclerotic lesions induces a diurnal rhythm of apoptosis regulated by circadian Mir21 expression in macrophages that is not matched by efferocytosis, thus increasing the size of the necrotic core.

8.
Eur Heart J ; 42(39): 4077-4088, 2021 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-34279021

RESUMO

AIMS: Mental stress substantially contributes to the initiation and progression of human disease, including cardiovascular conditions. We aim to investigate the underlying mechanisms of these contributions since they remain largely unclear. METHODS AND RESULTS: Here, we show in humans and mice that leucocytes deplete rapidly from the blood after a single episode of acute mental stress. Using cell-tracking experiments in animal models of acute mental stress, we found that stress exposure leads to prompt uptake of inflammatory leucocytes from the blood to distinct tissues including heart, lung, skin, and, if present, atherosclerotic plaques. Mechanistically, we found that acute stress enhances leucocyte influx into mouse atherosclerotic plaques by modulating endothelial cells. Specifically, acute stress increases adhesion molecule expression and chemokine release through locally derived norepinephrine. Either chemical or surgical disruption of norepinephrine signalling diminished stress-induced leucocyte migration into mouse atherosclerotic plaques. CONCLUSION: Our data show that acute mental stress rapidly amplifies inflammatory leucocyte expansion inside mouse atherosclerotic lesions and promotes plaque vulnerability.


Assuntos
Aterosclerose , Placa Aterosclerótica , Animais , Modelos Animais de Doenças , Células Endoteliais , Inflamação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
9.
Sensors (Basel) ; 21(13)2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34210063

RESUMO

A photoacoustic gas detector for SO2 was developed for ship exhaust gas emission monitoring. The basic measurement setup is based on the absorption of electromagnetic radiation of SO2 at 285 nm wavelength. A commercially available ultraviolet (UV) light-emitting diode (LED) is used as the light source and a micro-electro-mechanical system (MEMS) microphone as the detector. In order to achieve the required detection limits in marine applications, a measuring cell which allows an acoustically resonant amplification of the photoacoustic signal was developed and characterized. A limit of detection of 1 ppm was achieved in lab conditions during continuous gas flow. Long-term measurements on a container ship demonstrated the application relevance of the developed system.


Assuntos
Navios , Análise Espectral
10.
QJM ; 2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34293177

RESUMO

As current therapies for cardiovascular disease (CVD), predominantly based on lipid lowering, still face an unacceptable residual risk, novel treatment strategies are being explored. Besides lipids, inflammatory processes play a major role in the pathogenesis of atherosclerosis, the underlying cause of the majority of CVD. The first clinical trials targeting the interleukin-1ß-inflammasome axis have shown that targeting this pathway is successful in reducing cardiovascular events but did not decrease overall CVD mortality. Hence, novel and improved immunotherapeutics to treat CVD are being awaited. In this review we highlight novel immunotherapeutic approaches in CVD as well as future challenges ahead.

11.
Atherosclerosis ; 330: 95-106, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34247863

RESUMO

Chemokines and their receptors represent a potential target for immunotherapy in chronic inflammation. They comprise a large family of cytokines with chemotactic activity, and their cognate receptors are expressed on all cells of the body. This network dictates leukocyte recruitment and activation, angiogenesis, cell proliferation and maturation. Dysregulation of chemokine and chemokine receptor expression as well as function participates in many pathologies including cancer, autoimmune diseases and chronic inflammation. In atherosclerosis, a lipid-driven chronic inflammation of middle-sized and large arteries, chemokines and their receptors participates in almost all stages of the disease from initiation of fatty streaks to mature atherosclerotic plaque formation. Atherosclerosis and its complications are the main driver of mortality and morbidity in cardiovascular diseases (CVD). Hence, exploring new fields of therapeutic targeting of atherosclerosis is of key importance. This review gives an overview of the recent advances on the role of key chemokines and chemokine receptors in atherosclerosis, addresses chemokine-based biomarkers at biochemical, imaging and genetic level in human studies, and highlights the clinial trials targeting atherosclerosis.


Assuntos
Aterosclerose , Placa Aterosclerótica , Quimiocinas , Humanos , Imunoterapia , Receptores de Quimiocinas
12.
Life (Basel) ; 11(6)2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-34200546

RESUMO

Large (>3 cm2), focal osteochondral lesions (OCL) may result in poor functional outcomes and early secondary osteoarthritis of the knee. The surgical management of these OCL remains challenging. The treatment strategy must be tailored to various aspects, including lesion-specific (e.g., size, location, chronicity), joint-specific (e.g., instability, limb alignment, meniscal status), and patient-specific factors (e.g., age, activity level, comorbidities). Simple chondroplasty and bone marrow stimulation (BMS) techniques should be reserved for smaller lesions, as they only realize midterm clinical benefits, related to inferior wear characteristics of the induced fibrocartilage (type I collagen). Therefore, much attention has been focused on surgical restoration with hyaline cartilage (type II collagen), based on chondrocyte transplantation and matrix-assisted autologous chondrocyte implantation (MACI). Limited graft availability, staged procedures (MACI), and high treatment costs are limitations of these techniques. However, acute traumatic OCL of the femoral condyles and patellofemoral joint may also be suitable for preservation by surgical fixation. Early detection of the fragment facilitates primary repair with internal fixation. The surgical repair of the articular surface may offer promising clinical and cost-effective benefits as a first-line therapy but remains under-investigated and potentially under-utilized. As a unique characteristic, the fixation technique allows the anatomic restoration of the hyaline articular surface with native cartilage and the repair of the subchondral bone. In this manuscript, we present a case series of large OCL around the knee that were preserved by surgical fixation. Furthermore, various implants and techniques reported for this procedure are reviewed.

13.
Cardiovasc Res ; 117(10): 2161-2174, 2021 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-34114614

RESUMO

We review some of the important discoveries and advances made in basic and translational cardiac research in 2020. For example, in the field of myocardial infarction (MI), new aspects of autophagy and the importance of eosinophils were described. Novel approaches, such as a glycocalyx mimetic, were used to improve cardiac recovery following MI. The strategy of 3D bio-printing was shown to allow the fabrication of a chambered cardiac organoid. The benefit of combining tissue engineering with paracrine therapy to heal injured myocardium is discussed. We highlight the importance of cell-to-cell communication, in particular, the relevance of extracellular vesicles, such as exosomes, which transport proteins, lipids, non-coding RNAs, and mRNAs and actively contribute to angiogenesis and myocardial regeneration. In this rapidly growing field, new strategies were developed to stimulate the release of reparative exosomes in ischaemic myocardium. Single-cell sequencing technology is causing a revolution in the study of transcriptional expression at cellular resolution, revealing unanticipated heterogeneity within cardiomyocytes, pericytes and fibroblasts, and revealing a unique subpopulation of cardiac fibroblasts. Several studies demonstrated that exosome- and non-coding RNA-mediated approaches can enhance human induced pluripotent stem cell (iPSC) viability and differentiation into mature cardiomyocytes. Important details of the mitochondrial Ca2+ uniporter and its relevance were elucidated. Novel aspects of cancer therapeutic-induced cardiotoxicity were described, such as the novel circular RNA circITCH, which may lead to novel treatments. Finally, we provide some insights into the effects of SARS-CoV-2 on the heart.


Assuntos
Pesquisa Biomédica , Cardiologia , Proliferação de Células , Insuficiência Cardíaca/patologia , Infarto do Miocárdio/patologia , Traumatismo por Reperfusão Miocárdica/patologia , Miócitos Cardíacos/patologia , Regeneração , Animais , COVID-19/patologia , COVID-19/virologia , Comunicação Celular , Microambiente Celular , Exossomos/metabolismo , Exossomos/patologia , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Humanos , Mitocôndrias Cardíacas/metabolismo , Mitocôndrias Cardíacas/patologia , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/fisiopatologia , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/virologia , Fenótipo , RNA não Traduzido/metabolismo , SARS-CoV-2/patogenicidade
14.
Pract Lab Med ; 26: e00238, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34095419

RESUMO

Background: Acute bleeding requires fast and targeted therapy. Therefore, knowledge of the patient's potential to form a clot is crucial. Point-of-care testing (POCT) provides fast and reliable information on coagulation. Structural circumstances, such as person-bound sample transport, can prolong the reporting of the results. The aim of the present study was to investigate the diagnostic quality and accuracy between POCT INR diagnostics and standard laboratory analysis (SLA) as well as the time advantage between a pneumatic tube and a personal-based transport system. Methods: Two groups of haemorrhagic patients (EG: emergency department; OG: delivery room; each n = 12) were examined in the context of bleeding emergencies using POCT and SLA. Samples were transported via a pneumatic tube system or by a personal transport service. Results: INR results between POCT and SLA showed a high and significant correlation (EG: p < 0.001; OG: p < 0.001). POCT results were reported significantly more quickly (EG: 1.1 vs. 39.6 min; OG: 2.0 vs. 75.0 min; p < 0.001) and required less time for analysis (EG: 0.3 vs. 24.0 min; OG: 0.5 vs. 45.0 min; p < 0.001) compared to SLA. The time for transportation with the pneumatic tube was significantly shorter (8.0 vs. 18.5 min; p < 0.001) than with the personal-based transport system. Conclusion: The results of the present study suggest that POCT may be a suitable method for the emergency diagnosis and may be used as prognostic diagnostic elements in haemotherapy algorithms to initiate targeted haemotherapy at an early point in time.

15.
J Am Coll Cardiol ; 77(23): 2923-2935, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34112319

RESUMO

BACKGROUND: Pathological cardiac hypertrophy is a result of afterload-increasing pathologies including untreated hypertension and aortic stenosis. It features progressive adverse cardiac remodeling, myocardial dysfunction, capillary rarefaction, and interstitial fibrosis often leading to heart failure. OBJECTIVES: This study aimed to establish a novel porcine model of pressure-overload-induced heart failure and to determine the effect of inhibition of microribonucleic acid 132 (miR-132) on heart failure development in this model. METHODS: This study developed a novel porcine model of percutaneous aortic constriction by implantation of a percutaneous reduction stent in the thoracic aorta, inducing progressive remodeling at day 56 (d56) after pressure-overload induction. In this study, an antisense oligonucleotide specifically inhibiting miR-132 (antimiR-132), was regionally applied via intracoronary injection at d0 (percutaneous transverse aortic constriction induction) and d28. RESULTS: At d56, antimiR-132 treatment diminished cardiomyocyte cross-sectional area (188.9 ± 2.8 vs. 258.4 ± 9.0 µm2 in untreated hypertrophic hearts) and improved global cardiac function (ejection fraction 48.9 ± 1.0% vs. 36.1 ± 1.7% in control hearts). Moreover, at d56 antimiR-132-treated hearts displayed less increase of interstitial fibrosis compared with sham-operated hearts (Δsham 1.8 ± 0.5%) than control hearts (Δsham 10.8 ± 0.6%). Of note, cardiac platelet and endothelial cell adhesion molecule 1+ capillary density was higher in the antimiR-132-treated hearts (647 ± 20 cells/mm2) compared with in the control group (485 ± 23 cells/mm2). CONCLUSIONS: The inhibition of miR-132 is a valid strategy in prevention of heart failure progression in hypertrophic heart disease and may be developed as a treatment for heart failure of nonischemic origin.

16.
Vascul Pharmacol ; 139: 106884, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34102305

RESUMO

Atherosclerosis is a lipid-driven, chronic inflammatory disease. In spite of efficient lipid lowering treatments, such as statins and PCSK9 inhibitors, patients, especially those with elevated inflammatory biomarkers, still have a significant residual cardiovascular disease risk. Novel drugs targeting inflammatory mediators are needed to further reduce this residual risk. Agonistic immune checkpoint proteins, including CD86, CD40L and CD40, have been shown to be drivers of atherosclerosis. Recently, glucocorticoid-induced tumour necrosis factor receptor family-related protein (GITR), a co-stimulatory immune checkpoint protein, was identified to be pivotal in cardiovascular disease. Cardiovascular patients have elevated soluble GITR plasma levels compared to healthy controls. Furthermore, in human carotid endarterectomy plaques, GITR expression was higher in plaques from symptomatic compared to asymptomatic patients and correlated with features of plaque vulnerability. Moreover, depleting GITR reduced atherosclerotic plaque development in mice. GITR-deficient monocytes and macrophages exhibited less inflammatory potential and reduced migratory capacity. In this review, we discuss GITR's effects on various immune cells, mechanisms, signalling pathways and finally GITR's potential as a novel drug target in atherosclerosis.

17.
Nat Commun ; 12(1): 3754, 2021 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-34145241

RESUMO

Atherosclerosis is a major underlying cause of cardiovascular disease. Previous studies showed that inhibition of the co-stimulatory CD40 ligand (CD40L)-CD40 signaling axis profoundly attenuates atherosclerosis. As CD40L exerts multiple functions depending on the cell-cell interactions involved, we sought to investigate the function of the most relevant CD40L-expressing cell types in atherosclerosis: T cells and platelets. Atherosclerosis-prone mice with a CD40L-deficiency in CD4+ T cells display impaired Th1 polarization, as reflected by reduced interferon-γ production, and smaller atherosclerotic plaques containing fewer T-cells, smaller necrotic cores, an increased number of smooth muscle cells and thicker fibrous caps. Mice with a corresponding CD40-deficiency in CD11c+ dendritic cells phenocopy these findings, suggesting that the T cell-dendritic cell CD40L-CD40 axis is crucial in atherogenesis. Accordingly, sCD40L/sCD40 and interferon-γ concentrations in carotid plaques and plasma are positively correlated in patients with cerebrovascular disease. Platelet-specific deficiency of CD40L does not affect atherogenesis but ameliorates atherothrombosis. Our results establish divergent and cell-specific roles of CD40L-CD40 in atherosclerosis, which has implications for therapeutic strategies targeting this pathway.


Assuntos
Aterosclerose/patologia , Linfócitos T CD4-Positivos/metabolismo , Antígenos CD40/metabolismo , Ligante de CD40/metabolismo , Interferon gama/metabolismo , Placa Aterosclerótica/patologia , Animais , Plaquetas/metabolismo , Linfócitos T CD4-Positivos/citologia , Doenças Cardiovasculares/patologia , Células Dendríticas/imunologia , Camundongos , Camundongos Knockout , Miócitos de Músculo Liso/citologia , Transdução de Sinais/fisiologia , Trombose/patologia
19.
Genome Biol ; 22(1): 150, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33975635

RESUMO

BACKGROUND: The 3D organization of the chromatin fiber in cell nuclei plays a key role in the regulation of gene expression. Genome-wide techniques to score DNA-DNA contacts, such as Hi-C, reveal the partitioning of chromosomes into epigenetically defined active and repressed compartments and smaller "topologically associated" domains. These domains are often associated with chromatin loops, which largely disappear upon removal of cohesin. Because most Hi-C implementations average contact frequencies over millions of cells and do not provide direct spatial information, it remains unclear whether and how frequently chromatin domains and loops exist in single cells. RESULTS: We combine 3D single-molecule localization microscopy with a low-cost fluorescence labeling strategy that does not denature the DNA, to visualize large portions of single human chromosomes in situ at high resolution. In parallel, we develop multi-scale, whole nucleus polymer simulations, that predict chromatin structures at scales ranging from 5 kb up to entire chromosomes. We image chromosomes in G1 and M phase and examine the effect of cohesin on interphase chromatin structure. Depletion of cohesin leads to increased prevalence of loose chromatin stretches, increased gyration radii, and reduced smoothness of imaged chromatin regions. By comparison to model predictions, we estimate that 6-25 or more purely cohesin-dependent chromatin loops coexist per megabase of DNA in single cells, suggesting that the vast majority of the genome is enclosed in loops. CONCLUSION: Our results provide new constraints on chromatin structure and showcase an affordable non-invasive approach to study genome organization in single cells.

20.
Cell Death Dis ; 12(6): 516, 2021 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-34016957

RESUMO

Bone marrow-derived human mesenchymal stem cells (hMSCs) are recruited to damaged or inflamed tissues where they contribute to tissue repair. This multi-step process involves chemokine-directed invasion of hMSCs and on-site release of factors that influence target cells or tumor tissues. However, the underlying molecular mechanisms are largely unclear. Previously, we described that microRNA let-7f controls hMSC differentiation. Here, we investigated the role of let-7f in chemotactic invasion and paracrine anti-tumor effects. Incubation with stromal cell-derived factor-1α (SDF-1α) or inflammatory cytokines upregulated let-7f expression in hMSCs. Transfection of hMSCs with let-7f mimics enhanced CXCR4-dependent invasion by augmentation of pericellular proteolysis and release of matrix metalloproteinase-9. Hypoxia-induced stabilization of the hypoxia-inducible factor 1 alpha in hMSCs promoted cell invasion via let-7f and activation of autophagy. Dependent on its endogenous level, let-7f facilitated hMSC motility and invasion through regulation of the autophagic flux in these cells. In addition, secreted let-7f encapsulated in exosomes was increased upon upregulation of endogenous let-7f by treatment of the cells with SDF-1α, hypoxia, or induction of autophagy. In recipient 4T1 tumor cells, hMSC-derived exosomal let-7f attenuated proliferation and invasion. Moreover, implantation of 3D spheroids composed of hMSCs and 4T1 cells into a breast cancer mouse model demonstrated that hMSCs overexpressing let-7f inhibited tumor growth in vivo. Our findings provide evidence that let-7f is pivotal in the regulation of hMSC invasion in response to inflammation and hypoxia, suggesting that exosomal let-7f exhibits paracrine anti-tumor effects.


Assuntos
Quimiocina CXCL12/metabolismo , Neoplasias Mamárias Experimentais/metabolismo , Células-Tronco Mesenquimais/metabolismo , MicroRNAs/genética , Hipóxia Tumoral/fisiologia , Animais , Comunicação Celular/fisiologia , Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Modelos Animais de Doenças , Feminino , Humanos , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/patologia , Células-Tronco Mesenquimais/patologia , Camundongos , Camundongos Endogâmicos BALB C , MicroRNAs/biossíntese , Transfecção
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