RESUMEN
Distinct populations of Trypanosoma cruzi interact with mammalian cardiac muscle cells causing different inflammation patterns and low heart functionality. During T. cruzi infection, the extracellular ATP is hydrolyzed to tri- and/or diphosphate nucleotides, based on the infectivity, virulence, and regulation of the inflammatory response. T. cruzi carries out this hydrolysis through the T. cruzi ectonucleotidase, NTPDase-1 (TcNTPDase-1). This study aimed to evaluate the role of TcNTPDase-1 in culture rich in metacyclic trypomastigote forms (MT) and cell culture-derived trypomastigote forms (CT) from Colombiana (discrete typing unit - DTU I), VL-10 (DTU II), and CL (DTU VI) strains of T. cruzi. For this, we measured TcNTPDase-1 activity in suramin-treated and untreated parasites and infected J774 cells and C57BL/6 mice with suramin pre-treated parasites to assess parasitic and inflammatory cardiac profile in the acute phase of infection. Our data indicated a higher TcNTPDase-1 activity for ATP in culture rich in metacyclic trypomastigote forms from Colombiana strain in comparison to those from VL-10 and CL strains. The cell culture-derived trypomastigote forms from CL strain presented higher capacity to hydrolyze ATP than those from Colombiana and VL-10 strains. Suramin inhibited ATP hydrolysis in all studied parasite forms and strains. Suramin pre-treated parasites reduced J774 cell infection and increased nitrite production in vitro. In vivo studies showed a reduction of inflammatory infiltrate in the cardiac tissues of animals infected with cell culture-derived trypomastigote forms from suramin pre-treated Colombiana strain. In conclusion, TcNTPDase-1 activity in trypomastigotes forms drives part of the biological characteristics observed in distinct DTUs and may induce cardiac pathogenesis during T. cruzi infection.
Asunto(s)
Antígenos CD , Apirasa , Enfermedad de Chagas , Proteínas Protozoarias , Trypanosoma cruzi , Factores de Virulencia , Animales , Antígenos CD/genética , Antígenos CD/metabolismo , Apirasa/genética , Apirasa/metabolismo , Línea Celular Tumoral , Enfermedad de Chagas/enzimología , Enfermedad de Chagas/genética , Ratones , Ratones Endogámicos BALB C , Proteínas Protozoarias/genética , Proteínas Protozoarias/metabolismo , Especificidad de la Especie , Trypanosoma cruzi/enzimología , Trypanosoma cruzi/genética , Trypanosoma cruzi/patogenicidad , Factores de Virulencia/genética , Factores de Virulencia/metabolismoRESUMEN
PURPOSE: The objective is to analyze the antiangiogenic mechanism of suramab, a pharmaceutical compound of bevacizumab and suramin, in a rabbit model of corneal angiogenesis. MATERIAL AND METHODS: Corneal neovascularization was induced in four groups of six New Zealand White rabbits by applying a filter paper disk soaked in 1 M Na (OH) on the central cornea. Group one was treated after injury with intravenous suramab at a dose equivalent to 3 mg/kg of bevacizumab and 10 mg/kg of suramin. Group two was treated with intravenous bevacizumab (5 mg/kg). Group three was treated with 10 mg/kg of suramin while the control group received no treatment. Digital photographs were taken at days 9, 15, 21, and 35. Neovessel formation was quantified giving a 0-4 score to each quadrant according to the centripetal growth of the longest vessel (neovessel index, NVI). Animals were sacrificed at day 35. Corneas were processed for histology, immunohistochemistry, and Western-blot using primary antibodies against P2X2, basic fibroblast growth factor (bFGF), LYVE-1, PECAM-1, and vascular endothelial growth factor-A (VEGF-A). RESULTS: Suramab significantly reduced neovessel growth (mean NVI: 4.2) compared to bevacizumab (8.4), suramin (7.22), and control animals (12.2) at 35 days post-injury (p < 0.01). A lower protein expression of P2X2, bFGF, LYVE-1, PECAM-1, and VEGF-A was found in the cornea of suramab animals than in the other groups of animals. CONCLUSIONS: Joint downregulation of bFGF, P2X2, bFGF, and LYVE-1 constitutes a mechanism that induces greater and longer inhibition of corneal angiogenesis. Results might be relevant to ophthalmic care. Ocular administration of suramab is currently being investigated.
Asunto(s)
Bevacizumab/farmacología , Córnea/patología , Neovascularización de la Córnea/tratamiento farmacológico , Regulación hacia Abajo/efectos de los fármacos , Factor 2 de Crecimiento de Fibroblastos/biosíntesis , Receptores Purinérgicos P2X2/biosíntesis , Suramina/farmacología , Animales , Western Blotting , Córnea/metabolismo , Neovascularización de la Córnea/metabolismo , Neovascularización de la Córnea/patología , Modelos Animales de Enfermedad , Combinación de Medicamentos , Inmunohistoquímica , ConejosRESUMEN
The involvement of purinergic signaling in several brain functions has been recognized, but the modulation on maternal behavior by the purinergic system is not established, even though there are functional interactions between the purinergic and oxytocinergic systems. Therefore, the aim of our study was to investigate whether central administration of P2 receptor antagonists affected the maternal behavior of lactating rats and c-Fos immunoreactivity in the forebrain. On day 7 of lactation, female rats were treated with vehicle (5µL; i.c.v.), suramin (9.4-75.0µg/5µL; i.c.v.) or PPADS (9.4-75.0µg/5µL; i.c.v.) 30min before the experiment began. The maternal behavior was evaluated during the 30min following suramin or PPADS administration. In addition, c-Fos-positive nuclei were counted in the medial preoptic area (MPOA) and in the bed nucleus of the stria terminalis (BNST), and neurons that were double-labeled for c-Fos/OT were counted in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus of lactating rats. The results show that P2 receptor antagonists decreased maternal care and decreased neuronal activation in the MPOA and BNST and activation of oxytocinergic neurons in hypothalamic nuclei. Our results indicate that the purinergic system modulates maternal behavior and neuronal activation induced by suckling during lactation.
Asunto(s)
Conducta Animal , Lactancia , Antagonistas del Receptor Purinérgico P2/farmacología , Animales , Femenino , Prosencéfalo/efectos de los fármacos , Prosencéfalo/metabolismo , Proteínas Proto-Oncogénicas c-fos/metabolismo , Fosfato de Piridoxal/análogos & derivados , Fosfato de Piridoxal/farmacología , Ratas , Ratas Wistar , Suramina/farmacologíaRESUMEN
INTRODUCTION: In Duchenne muscular dystrophy (DMD) and in the mdx mouse model of DMD, the lack of dystrophin leads to increased calcium influx and muscle necrosis. Patients suffer progressive muscle loss, and cardiomyopathy is an important determinant of morbidity. P2 purinergic receptors participate in the increased calcium levels in dystrophic skeletal muscles. METHODS: In this study, we evaluated whether P2 receptors are involved in cardiomyopathy in mdx mice at later stages of the disease. RESULTS: Western blotting revealed that P2Y2 receptor levels were upregulated (54%) in dystrophic heart compared with a normal heart. Suramin reduced the levels of P2Y2 to almost normal values. Suramin also decreased heart necrosis (reduced CK-MB) and the expression of the stretch-activated calcium channel TRPC1. CONCLUSIONS: This study suggests that P2Y2 may participate in cardiomyopathy in mdx mice. P2-selective drugs with specific actions in the dystrophic heart may ameliorate cardiomyopathy in dystrophinopathies. Muscle Nerve 55: 116-121, 2017.
Asunto(s)
Antinematodos/farmacología , Diafragma/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Miocardio/metabolismo , Receptores Purinérgicos P2Y2/metabolismo , Suramina/farmacología , Animales , Calcio/metabolismo , Creatina Quinasa/sangre , Diafragma/metabolismo , Modelos Animales de Enfermedad , Regulación de la Expresión Génica/genética , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos mdx , Distrofia Muscular Animal/genética , Distrofia Muscular Animal/patología , Receptores Purinérgicos P2Y2/genética , Canales Catiónicos TRPC/metabolismoRESUMEN
Local myonecrosis resulting from snakebite envenomation is not efficiently neutralized by regular antivenom administration. This limitation is considered to be a significant health problem by the World Health Organization. Phospholipase A2-like (PLA2-like) proteins are among the most important proteins related to the muscle damage resulting from several snake venoms. However, despite their conserved tertiary structure compared with PLA2s, their biological mechanism remains incompletely understood. Different oligomeric conformations and binding sites have been identified or proposed, leading to contradictory data in the literature. In the last few years, a comprehensive hypothesis has been proposed based on fatty-acid binding, allosteric changes and the presence of two different interaction sites. In the present study, a combination of techniques were used to fully understand the structural-functional characteristics of the interaction between suramin and MjTX-II (a PLA2-like toxin). In vitro neuromuscular studies were performed to characterize the biological effects of the protein-ligand interaction and demonstrated that suramin neutralizes the myotoxic activity of MjTX-II. The high-resolution structure of the complex identified the toxin-ligand interaction sites. Calorimetric assays showed two different binding events between the protein and the inhibitor. It is demonstrated for the first time that the inhibitor binds to the surface of the toxin, obstructing the sites involved in membrane docking and disruption according to the proposed myotoxic mechanism. Furthermore, higher-order oligomeric formation by interaction with interfacial suramins was observed, which may also aid the inhibitory process. These results further substantiate the current myotoxic mechanism and shed light on the search for efficient inhibitors of the local myonecrosis phenomenon.
Asunto(s)
Antivenenos/farmacología , Bothrops/metabolismo , Venenos de Crotálidos/antagonistas & inhibidores , Venenos de Crotálidos/metabolismo , Fosfolipasas A/antagonistas & inhibidores , Fosfolipasas A/metabolismo , Suramina/farmacología , Animales , Sitios de Unión , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Venenos de Crotálidos/química , Venenos de Crotálidos/toxicidad , Cristalografía por Rayos X , Masculino , Ratones , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Fosfolipasas A/química , Fosfolipasas A/toxicidadRESUMEN
INTRODUCTION: The purpose of this study was to determine the effects of suramin, an antifibrotic agent, on cardiac function and remodeling in mdx mice. METHODS: mdx mice (8 months old) received intraperitoneal injections of suramin twice a week for 3 months. Control mdx mice (8 months old) were injected with saline. RESULTS: Suramin improved the electrocardiography profile with the main corrections seen in S- to R-wave ratio, PR interval, and Q amplitude, and a significant decrease in the cardiomyopathy index. Suramin decreased myocardial fibrosis, inflammation, and myonecrosis. CONCLUSIONS: These findings suggest that suramin may be a new adjunctive therapy to help improve cardiomyopathy in DMD.