RESUMO
Romiplostim, a thrombopoietin (TPO) receptor agonist, is a clinically approved drug that is clearly effective in reconstituting hematopoiesis in refractory aplastic anemia andãidiopathic thrombocytopenic purpura. However, the mechanism underlying its biological effect is unknown, and its differences from other TPO receptor agonists remain unclear. Therefore, we determined the in vitro expansion effect of romiplostim on human CD34 + hematopoietic stem and progenitor cells (HSPCs) versus recombinant human TPO (rhTPO) and another clinically available drug, eltrombopag. We also performed single-cell RNA-seq to determine effects of romiplostim on CD34 + HSPCs at the molecular level. The maximum expansion effect of romiplostim on total CD34 + cells, CD34 + CD38 + progenitor cells, and CD34 + CD38 - immature cells was comparable to that of rhTPO, but higher than that of eltrombopag, particularly on CD34 + CD38 - immature cells. Single-cell RNA-seq analysis revealed that both romiplostim and eltrombopag induced signatures driven by rhTPO, but romiplostim induced molecular changes related to RHOA signaling in the most primitive HSPC subsets that were partially driven or not driven by eltrombopag. Additionally, romiplostim did not induce TFRC expression as was observed with eltrombopag. In conclusion, romiplostim expands and affects human HSPCs similar to rhTPO, but partially different from eltrombopag in terms of induction of gene expression.
RESUMO
The kidney is a complex organ that consists of various types of cells. It is occasionally difficult to resolve molecular alterations and possible perturbations that the kidney experiences due to drug-induced damage. In this study, we performed spatial and single-cell transcriptome analysis of rat kidneys and constructed a precise rat renal cell atlas with spatial information. Using the constructed catalogue, we were able to characterize cells of several minor populations, such as macula densa or juxtaglomerular cells. Further inspection of the spatial gene expression data allowed us to identify the upregulation of genes involved in the renin regulating pathway in losartan-treated populations. Losartan is an angiotensin II receptor antagonist drug, and the observed upregulation of the renin pathway-related genes could be due to feedback from the hypotensive action of the drug. Furthermore, we found spatial heterogeneity in the response to losartan among the glomeruli. These results collectively indicate that integrated single-cell and spatial gene expression analysis is a powerful approach to reveal the detailed associations between the different cell types spanning the complicated renal compartments.
Assuntos
Losartan , Renina , Animais , Expressão Gênica , Perfilação da Expressão Gênica , Rim/metabolismo , Losartan/metabolismo , Losartan/farmacologia , Ratos , Renina/genética , Renina/metabolismoRESUMO
Pertussis, also known as whooping cough, is a contagious respiratory disease caused by the Gram-negative bacterium Bordetella pertussis. This disease is characterized by severe and uncontrollable coughing, which imposes a significant burden on patients. However, its etiological agent and the mechanism are totally unknown because of a lack of versatile animal models that reproduce the cough. Here, we present a mouse model that reproduces coughing after intranasal inoculation with the bacterium or its components and demonstrate that lipooligosaccharide (LOS), pertussis toxin (PTx), and Vag8 of the bacterium cooperatively function to cause coughing. Bradykinin induced by LOS sensitized a transient receptor potential ion channel, TRPV1, which acts as a sensor to evoke the cough reflex. Vag8 further increased bradykinin levels by inhibiting the C1 esterase inhibitor, the major downregulator of the contact system, which generates bradykinin. PTx inhibits intrinsic negative regulation systems for TRPV1 through the inactivation of Gi GTPases. Our findings provide a basis to answer long-standing questions on the pathophysiology of pertussis cough. IMPORTANCE The Gram-negative bacterium Bordetella pertussis causes a respiratory disease called whooping cough, or pertussis. This disease is characterized by paroxysmal coughing, the mechanism of which has not been intensively studied because of a lack of versatile animal models that reproduce the cough. In this study, we present a mouse model that reproduces coughing after intranasal inoculation with the bacterium or its components. Using this model, we demonstrate that lipooligosaccharide, Vag8, and pertussis toxin of the bacteria cooperatively function to cause coughing. Our results also indicate that bradykinin, an inflammatory mediator, and TRPV1, an ion channel linked to nociceptive signaling, are host factors involved in the coughing mechanism.
Assuntos
Coqueluche , Animais , Bordetella pertussis/fisiologia , Bradicinina , Tosse/etiologia , Modelos Animais de Doenças , Humanos , Camundongos , Toxina Pertussis , Fatores de Transcrição , Coqueluche/microbiologiaRESUMO
An autotransporter of Bordetella pertussis, virulence-associated gene 8 (Vag8), binds and inactivates the complement regulator, C1 inhibitor (C1-Inh), and plays a role in evasion of the complement system. However, the molecular interaction between Vag8 and C1-Inh remains unclear. Here, we localized the minimum region of Vag8 required for interaction with C1-Inh by examining the differently truncated Vag8 derivatives for the ability to bind and inactivate C1-Inh. The truncated Vag8 containing amino-acid residues 102-548, but not 102-479 and 202-648, showed the full activity of intact Vag8, suggesting that the separate 102-202 and 548-648 amino-acid regions of Vag8 mediate the interaction with C1-Inh.
Assuntos
Proteínas de Bactérias/genética , Bordetella pertussis/genética , Proteína Inibidora do Complemento C1/imunologia , Sistemas de Secreção Tipo V/genética , Sequência de Aminoácidos , Proteínas de Bactérias/imunologia , Bordetella pertussis/patogenicidade , Interações Hospedeiro-Patógeno , Humanos , Evasão da Resposta Imune , Ligação Proteica , Sistemas de Secreção Tipo V/imunologia , Virulência/genética , Coqueluche/microbiologiaRESUMO
Spontaneous coronary artery dissection (SCAD) is a rare cause of acute myocardial ischemia. Identification of intimal flap, true and false lumens in coronary angiogram (CAG) is the standard method to diagnose SCAD. In cases of obscure intimal flap, intravascular ultrasound (IVUS) is a useful method to diagnose, although crossing the wire and IVUS in the dissected lesion is invasive. Multidetector computed tomography (MDCT) provides valuable information in any clinical setting less invasively. We report here a rare case of spontaneous dissecting coronary artery pseudoaneurysm diagnosed by CAG and MDCT, healed by medical treatment, and followed up by MDCT over a 2-year period.
RESUMO
Cardiac free wall rupture after myocardial infarction is one of the life-threatening complications, which often results in sudden onset of cardiogenic shock caused by cardiac tamponade. Multidetector computed tomography (MDCT) provides valuable information in any clinical setting. There have been a few case reports on detecting cardiac rupture by means of CT. We report here a rare case of postinfarct cardiac free wall rupture, whose myocardial tear could be detected by MDCT.