Rocha-Hasler Marianne, de Oliveira Gabriel Melo, da Gama Aline Nefertiti, Fiuza Ludmila Ferreira de Almeida, Fesser Anna Frieda, Cal Monica, Rocchetti Romina, Peres Raiza Brandão, Guan Xue Li, Kaiser Marcel, Soeiro Maria de Nazaré Correia, Mäser Pascal
Laboratório de Biologia Celular, Instituto Oswaldo Cruz (IOC/Fiocruz), Pavilhão Cardoso Fontes, Rio de Janeiro, Brazil.
Parasite Chemotherapy Unit, Swiss Tropical and Public Health Institute, Medical Parasitology and Infection Biology, Basel, Switzerland.
Front Cell Infect Microbiol. 2021 Mar 4;11:617917. doi: 10.3389/fcimb.2021.617917. eCollection 2021.
Azoles such as posaconazole (Posa) are highly potent against . However, when tested in chronic Chagas disease patients, a high rate of relapse after Posa treatment was observed. It appears that inhibition of cytochrome CYP51, the target of azoles, does not deliver sterile cure in monotherapy. Looking for suitable combination partners of azoles, we have selected a set of inhibitors of sterol and sphingolipid biosynthetic enzymes. A small-scale phenotypic screening was conducted against the proliferative forms of , extracellular epimastigotes and intracellular amastigotes. Against the intracellular, clinically relevant forms, four out of 15 tested compounds presented higher or equal activity as benznidazole (Bz), with EC values ≤2.2 μM. Ro48-8071, an inhibitor of lanosterol synthase (ERG7), and the steroidal alkaloid tomatidine (TH), an inhibitor of C-24 sterol methyltransferase (ERG6), exhibited the highest potency and selectivity indices (SI = 12 and 115, respectively). Both were directed to combinatory assays using fixed-ratio protocols with Posa, Bz, and fexinidazole. The combination of TH with Posa displayed a synergistic profile against amastigotes, with a mean ΣFICI value of 0.2. assays using an acute mouse model of infection demonstrated lack of antiparasitic activity of TH alone in doses ranging from 0.5 to 5 mg/kg. As observed , the best combo proportion was the ratio 3 TH:1 Posa. The combination of Posa at 1.25 mpk plus TH at 3.75 mpk displayed suppression of peak parasitemia of 80% and a survival rate of 60% in the acute infection model, as compared to 20% survival for Posa at 1.25 mpk alone and 40% for Posa at 10 mpk alone. These initial results indicate a potential for the combination of posaconazole with tomatidine against .
泊沙康唑（Posa）等唑类药物对……具有高度活性。然而，在慢性恰加斯病患者中进行测试时，观察到Posa治疗后复发率很高。似乎抑制唑类药物的靶点细胞色素CYP51并不能通过单一疗法实现无菌治愈。为了寻找唑类药物合适的联合用药伙伴，我们选择了一组甾醇和鞘脂生物合成酶抑制剂。针对……的增殖形式，即细胞外无鞭毛体和细胞内无鞭毛体进行了小规模表型筛选。针对细胞内具有临床相关性的形式，15种受试化合物中有4种表现出与苯硝唑（Bz）相同或更高的活性，其半数有效浓度（EC）值≤2.2 μM。羊毛甾醇合酶（ERG7）抑制剂Ro48 - 8071和C - 24甾醇甲基转移酶（ERG6）抑制剂甾体生物碱番茄碱（TH）表现出最高的效力和选择性指数（SI分别为12和115）。二者都采用固定比例方案与Posa、Bz和非昔硝唑进行联合试验。TH与Posa的组合对无鞭毛体表现出协同作用，平均联合抑菌系数（ΣFICI）值为0.2。使用急性小鼠感染模型进行的试验表明，单独使用TH在0.5至5 mg/kg剂量范围内缺乏抗寄生虫活性。如前所述，最佳组合比例是3 TH:1 Posa。在急性感染模型中，1.25 mpk的Posa加3.75 mpk的TH组合显示出对最高血虫率的抑制率为80%，存活率为60%，而单独使用1.25 mpk的Posa存活率为20%，单独使用10 mpk的Posa存活率为40%。这些初步结果表明泊沙康唑与番茄碱联合使用对……具有潜在作用。
