RESUMEN
Overactivation of the mineralocorticoid receptor (MR) is involved in many diseases, such as hypertension, kidney disease, and heart failure. Thus, MR antagonists (MRAs) are expected to be beneficial to patients with these diseases. In order to identify novel nonsteroidal MRAs that overcome the issues of already marketed steroidal MRAs, we searched for new compounds guided by our hypothesis that T-shaped compounds with a hydrophobic core structure, two polar functional groups at both extremities able to interact with MR, and a bulky substituent that can interfere with the folding of the C-terminal helix 12 may exhibit antagonist activity toward MR. We discovered that the novel 1,4-benzoxazin-3-one derivative 19 (apararenone: MT-3995) acted as a highly selective and potent nonsteroidal MRA. Apararenone exhibited a more potent antihypertensive and organ-protective activity than steroidal MRA eplerenone in a primary aldosteronism rat model obtained by infusing aldosterone in uninephrectomized rats.
Asunto(s)
Insuficiencia Cardíaca , Antagonistas de Receptores de Mineralocorticoides , Animales , Antihipertensivos , Eplerenona/farmacología , Humanos , Antagonistas de Receptores de Mineralocorticoides/química , Antagonistas de Receptores de Mineralocorticoides/farmacología , Antagonistas de Receptores de Mineralocorticoides/uso terapéutico , Oxazinas , Ratas , Receptores de Mineralocorticoides , SulfonamidasRESUMEN
The calcium-sensing receptor (CaSR) plays an important role in sensing extracellular calcium ions and regulating parathyroid hormone secretion by parathyroid gland cells, and the receptor is a suitable target for the treatment of hyperparathyroidism. Cinacalcet hydrochloride is a representative CaSR agonist which widely used for the hyperparathyroidism. However, it has several issues to clinical use, such as nausea/vomiting and strong inhibition of CYP2D6. We tried to improve these issues of cinacalcet for a new pharmaceutical agent as a preferable CaSR agonist. Optimization from cinacalcet resulted in the identification of pyrrolidine compounds and successfully led to the discovery of evocalcet as an oral allosteric CaSR agonist. Evocalcet, which exhibited highly favorable profiles such as CaSR agonistic activity and good DMPK profiles, will provide a novel therapeutic option for secondary hyperparathyroidism.
Asunto(s)
Inhibidores Enzimáticos del Citocromo P-450/farmacología , Sistema Enzimático del Citocromo P-450/metabolismo , Descubrimiento de Drogas , Hiperparatiroidismo/tratamiento farmacológico , Pirrolidinas/farmacología , Receptores Sensibles al Calcio/agonistas , Animales , Inhibidores Enzimáticos del Citocromo P-450/síntesis química , Inhibidores Enzimáticos del Citocromo P-450/química , Relación Dosis-Respuesta a Droga , Humanos , Modelos Moleculares , Estructura Molecular , Pirrolidinas/síntesis química , Pirrolidinas/química , Ratas , Relación Estructura-ActividadRESUMEN
Immunoglobulin G4-related disease is a rare immune-mediated disease characterized by the infiltration of IgG4-positive plasma cells and unique storiform fibrosis of multiple organs. The majority of IgG4-related disease patients respond to glucocorticoids, yet the precise mechanism of their action remains unclear. Pathological sections of the submaxillary gland, kidney, and retroperitoneum from 20 patients in total diagnosed with IgG4-related disease were analyzed for glucocorticoid receptor expression and the cell types expressing glucocorticoid receptor. Strong and abundant expression of glucocorticoid receptor was observed in the submaxillary gland, kidney, and retroperitoneum of IgG4-related disease patients, while glucocorticoid receptor was rarely or only faintly observed in the submaxillary gland of patients with Sjögren's syndrome, radicular cysts and sialolithiasis or in the healthy kidney. Glucocorticoid receptor was mainly expressed in fibro/myofibroblasts, CD4-positive T cells and IgG4-positive plasma cells in the submandibular glands and kidneys of IgG4-related disease patients. The abundant expression of glucocorticoid receptor in various types of cells, including resident fibro/myofibroblasts in IgG4-related disease patients might provide clues to the mechanism of steroid responsiveness in IgG4-related disease patients.
Asunto(s)
Enfermedad Relacionada con Inmunoglobulina G4/metabolismo , Riñón/metabolismo , Receptores de Glucocorticoides/metabolismo , Glándula Submandibular/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Enfermedad Relacionada con Inmunoglobulina G4/patología , Riñón/patología , Masculino , Persona de Mediana Edad , Miofibroblastos/metabolismo , Miofibroblastos/patología , Peritoneo/metabolismo , Peritoneo/patología , Síndrome de Sjögren/metabolismo , Síndrome de Sjögren/patología , Glándula Submandibular/patologíaRESUMEN
Epidemiological findings indicate that acute kidney injury (AKI) increases the risk for chronic kidney disease (CKD), although the molecular mechanism remains unclear. Genetic fate mapping demonstrated that nephrons, functional units in the kidney, are repaired by surviving nephrons after AKI. However, the cell population that repairs damaged nephrons and their repair capacity limitations remain controversial. To answer these questions, we generated a new transgenic mouse strain in which mature proximal tubules, the segment predominantly damaged during AKI, could be genetically labelled at desired time points. Using this strain, massive proliferation of mature proximal tubules is observed during repair, with no dilution of the genetic label after the repair process, demonstrating that proximal tubules are repaired mainly by their own proliferation. Furthermore, acute tubular injury caused significant shortening of proximal tubules associated with interstitial fibrosis, suggesting that proximal tubules have a limited capacity to repair. Understanding the mechanism of this limitation might clarify the mechanism of the AKI-to-CKD continuum.
Asunto(s)
Lesión Renal Aguda/fisiopatología , Riñón/fisiología , Regeneración/fisiología , Lesión Renal Aguda/patología , Animales , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proliferación Celular/fisiología , Fibrosis/patología , Fibrosis/fisiopatología , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Riñón/patología , Túbulos Renales Proximales/metabolismo , Túbulos Renales Proximales/patología , Túbulos Renales Proximales/fisiología , Ratones Endogámicos C57BL , Ratones TransgénicosRESUMEN
Diabetic nephropathy is a major complication in diabetes and a leading cause of end-stage renal failure. Glomerular podocytes are functionally and structurally injured early in diabetic nephropathy. A non-obese type 2 diabetes model, the spontaneously diabetic Torii (SDT) rat, is of increasing preclinical interest because of its pathophysiological similarities to human type 2 diabetic complications including diabetic nephropathy. However, podocyte injury in SDT rat glomeruli and the effect of angiotensin II receptor blocker treatment in the early stage have not been reported in detail. Therefore, we have evaluated early stages of glomerular podocyte damage and the beneficial effect of early treatment with losartan in SDT rats using desmin as a sensitive podocyte injury marker. Moreover, we have developed an automated, computational glomerulus recognition method and illustrated its specific application for quantitatively studying glomerular desmin immunoreactivity. This state-of-the-art method enabled automatic recognition and quantification of glomerular desmin-positive areas, eliminating the need to laboriously trace glomerulus borders by hand. The image analysis method not only enabled assessment of a large number of glomeruli, but also clearly demonstrated that glomerular injury was more severe in the juxtamedullary region than in the superficial cortex region. This applied not only in SDT rat diabetic nephropathy but also in puromycin aminonucleoside-induced nephropathy, which was also studied. The proposed glomerulus image analysis method combined with desmin immunohistochemistry should facilitate evaluations in preclinical drug efficacy studies as well as elucidation of the pathophysiology of diabetic nephropathy.
Asunto(s)
Desmina/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Nefropatías Diabéticas/metabolismo , Procesamiento de Imagen Asistido por Computador , Glomérulos Renales/metabolismo , Losartán/uso terapéutico , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Bloqueadores del Receptor Tipo 1 de Angiotensina II/uso terapéutico , Animales , Biomarcadores/metabolismo , Glucemia/metabolismo , Peso Corporal/efectos de los fármacos , Peso Corporal/fisiología , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/patología , Nefropatías Diabéticas/etiología , Nefropatías Diabéticas/patología , Modelos Animales de Enfermedad , Glomérulos Renales/efectos de los fármacos , Glomérulos Renales/patología , Losartán/farmacología , Masculino , Podocitos/efectos de los fármacos , Podocitos/metabolismo , Podocitos/patología , Ratas , Ratas Mutantes , Ratas Sprague-DawleyRESUMEN
Podocyte injury is the first step in the progression of glomerulosclerosis. Previous studies have demonstrated the beneficial effect of bone morphogenetic protein 7 (Bmp7) in podocyte injury and the existence of native Bmp signaling in podocytes. Local activity of Bmp7 is controlled by cell-type specific Bmp antagonists, which inhibit the binding of Bmp7 to its receptors. Here we show that the product of Twisted gastrulation (Twsg1), a Bmp antagonist, is the central negative regulator of Bmp function in podocytes and that Twsg1 null mice are resistant to podocyte injury. Twsg1 was the most abundant Bmp antagonist in murine cultured podocytes. The administration of Bmp induced podocyte differentiation through Smad signaling, whereas the simultaneous administration of Twsg1 antagonized the effect. The administration of Bmp also inhibited podocyte proliferation, whereas simultaneous administration of Twsg1 antagonized the effect. Twsg1 was expressed in the glomerular parietal cells (PECs) and distal nephron of the healthy kidney, and additionally in damaged glomerular cells in a murine model of podocyte injury. Twsg1 null mice exhibited milder hypoalbuminemia and hyperlipidemia, and milder histological changes while maintaining the expression of podocyte markers during podocyte injury model. Taken together, our results show that Twsg1 plays a critical role in the modulation of protective action of Bmp7 on podocytes, and that inhibition of Twsg1 is a promising means of development of novel treatment for podocyte injury.
Asunto(s)
Proteína Morfogenética Ósea 7/antagonistas & inhibidores , Proteína Morfogenética Ósea 7/metabolismo , Podocitos/metabolismo , Proteínas/metabolismo , Animales , Diferenciación Celular/fisiología , Células Cultivadas , Glomérulos Renales/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Nefronas/metabolismo , Transducción de Señal/fisiología , Proteínas Smad/metabolismoRESUMEN
BACKGROUND: Viral protein R (Vpr), a protein of human immunodeficiency virus type-1 (HIV-1) with various biological functions, was shown to be present in the blood of HIV-1-positive patients. However, it remained unclear whether circulating Vpr in patients' blood is biologically active. Here, we examined the activity of blood Vpr using an assay system by which retrotransposition of long interspersed element-1 (L1-RTP) was detected. We also investigated the in vivo effects of recombinant Vpr (rVpr) by administrating it to transgenic mice harboring human L1 as a transgene (hL1-Tg mice). Based on our data, we discuss the involvement of blood Vpr in the clinical symptoms of acquired immunodeficiency syndrome (AIDS). RESULTS: We first discovered that rVpr was active in induction of L1-RTP. Biochemical analyses revealed that rVpr-induced L1-RTP depended on the aryl hydrocarbon receptor, mitogen-activated protein kinases, and CCAAT/enhancer-binding protein ß. By using a sensitive L1-RTP assay system, we showed that 6 of the 15 blood samples from HIV-1 patients examined were positive for induction of L1-RTP. Of note, the L1-RTP-inducing activity was blocked by a monoclonal antibody specific for Vpr. Moreover, L1-RTP was reproducibly induced in various organs, including the kidney, when rVpr was administered to hL1-Tg mice. CONCLUSIONS: Blood Vpr is biologically active, suggesting that its monitoring is worthwhile for clarification of the roles of Vpr in the pathogenesis of AIDS. This is the first report to demonstrate a soluble factor in patients' blood active for L1-RTP activity, and implies the involvement of L1-RTP in the development of human diseases.
Asunto(s)
Productos del Gen vpr/sangre , Productos del Gen vpr/metabolismo , VIH-1/enzimología , Elementos de Nucleótido Esparcido Largo , Recombinación Genética , Adulto , Animales , Humanos , Masculino , Ratones , Ratones Transgénicos , Adulto JovenRESUMEN
APJ is a G-protein-coupled receptor with seven transmembrane domains, and its endogenous ligand, apelin, was identified recently. They are highly expressed in the cardiovascular system, suggesting that APJ is important in the regulation of blood pressure. To investigate the physiological functions of APJ, we have generated mice lacking the gene encoding APJ. The base-line blood pressure of APJ-deficient mice is equivalent to that of wild-type mice in the steady state. The administration of apelin transiently decreased the blood pressure of wild-type mice and a hypertensive model animal, a spontaneously hypertensive rat. On the other hand, this hypotensive response to apelin was abolished in APJ-deficient mice. This apelin-induced response was inhibited by pretreatment with a nitric-oxide synthase inhibitor, and apelin-induced phosphorylation of endothelial nitric-oxide synthase in lung endothelial cells from APJ-deficient mice disappeared. In addition, APJ-deficient mice showed an increased vasopressor response to the most potent vasoconstrictor angiotensin II, and the base-line blood pressure of double mutant mice homozygous for both APJ and angiotensin-type 1a receptor was significantly elevated compared with that of angiotensin-type 1a receptor-deficient mice. These results demonstrate that APJ exerts the hypotensive effect in vivo and plays a counterregulatory role against the pressor action of angiotensin II.