Killing Two Birds with One Stone: Discovery of Dual Inhibitors of Oxygen and Fumarate Respiration in Zoonotic Parasite, Echinococcus multilocularis.

Ascofuranone (AF), a meroterpenoid isolated from various filamentous fungi, including Acremonium egyptiacum, has been reported as a potential lead candidate for drug development against parasites and cancer. In this study, we demonstrated that AF and its derivatives are potent anthelminthic agents, particularly against Echinococcus multilocularis, which is the causative agent of alveolar echinococcosis. We measured the inhibitory activities of AF and its derivatives on the mitochondrial aerobic and anaerobic respiratory systems of E. multilocularis larvae. Several derivatives inhibited complex II (succinate:quinone reductase [SQR]; IC50 = 0.037 to 0.135 µM) and also complex I to III (NADH:cytochrome c reductase; IC50 = 0.008 to 0.401 µM), but not complex I (NADH:quinone reductase), indicating that mitochondrial complexes II and III are the targets. In particular, complex II inhibition in the anaerobic pathway was notable because E. multilocularis employs NADH:fumarate reductase (fumarate respiration), in addition to NADH oxidase (oxygen respiration), resulting in complete shutdown of ATP synthesis by oxidative phosphorylation. A structure-activity relationship study of E. multilocularis complex II revealed that the functional groups of AF are essential for inhibition. Binding mode prediction of AF derivatives to complex II indicated potential hydrophobic and hydrogen bond interactions between AF derivatives and amino acid residues within the quinone binding site. Ex vivo culture assays revealed that AF derivatives progressively reduced the viability of protoscoleces under both aerobic and anaerobic conditions. These findings confirm that AF and its derivatives are the first dual inhibitors of fumarate and oxygen respiration in E. multilocularis and are potential lead compounds in the development of anti-echinococcal drugs.

Data on the combined effect of atovaquone, mefloquine, and 3-bromopyruvic acid against Echinococcus multilocularis protoscoleces.

The dataset presented here is related to a previous research article titled "Mitochondrial Complex III in Larval Stage of Echinococcus multilocularis as a Potential Chemotherapeutic Target and in vivo Efficacy of Atovaquone Against Primary Hydatid Cysts"[1]. In this report, data were collected from aerobic and anaerobic culture assays of E. multilocularis protoscoleces in the presence of three anti-echinococcal drug candidates (atovaquone, mefloquine, and 3-bromopyruvic acid). The data were analyzed for viability of the protoscoleces between day 0 and day 7 upon adding drug candidates. In aerobic condition, all drug candidates caused damage to the protoscoleces, as described previously [1], [2], [3], [4], [5], [6]. Mefloquine, alone as well as in combination with atovaquone, immediately eliminated the protoscoleces, whereas combination of atovaquone with 3-bromopyruvic acid did not show clear synergy. In anaerobic condition, mefloquine, alone as well as in combination with atovaquone, eliminated protoscoleces immediately. 3-Bromopyruvic acid showed stronger efficacy in anaerobic condition than in aerobic condition. Combination of atovaquone with 3-bromopyruvic acid eliminated the protoscoleces, indicating that synergy occurred only under anaerobic condition. The data clarified that combined use of the three drugs eliminated protoscoleces in both aerobic and anaerobic conditions, hence suggesting that these could inhibit aerobic and anaerobic respiration pathways of Echinococcus multilocularis in vivo. The obtained data would be useful for the development of new drug dosing method for alveolar echinococcosis.

Longitudinal Glycaemic Profiles during Remission in 6q24-Related Transient Neonatal Diabetes Mellitus.

INTRODUCTION: Transient neonatal diabetes mellitus (TNDM) is a rare condition that is characterized by the presence of diabetes mellitus during the first 6 months of life and remission by 18 months of age. It usually relapses at a median age of 14 years. Hyperinsulinaemic hypoglycaemia is a relatively common complication during remission. Although ß-cell function is reported to be impaired at relapse, the clinical course of glycaemic profiles during remission in patients with TNDM remains largely unknown. CASE PRESENTATION: Longitudinal glycaemic profiles were investigated annually from remission (185 days) to relapse (14.5 years) in a patient with TNDM due to paternal 6q24 duplication using the oral glucose tolerance test (glucose intake: 1.75 g/kg to a maximum of 75 g). The patient's ß-cell function and insulin sensitivity were assessed by calculating the insulinogenic index, homeostasis model assessment of ß-cell function (HOMA-ß), homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index, and Matsuda index. Early insulin response to glucose intake was impaired throughout remission, whereas fasting insulin and ß-cell function by HOMA-ß gradually increased in the first few years since remission, followed by a gradual decline in function. In contrast, HOMA-IR fluctuated and peaked at 6.5 years of age. CONCLUSION: This is the first report of annual longitudinal glycaemic profiles in a patient with 6q24-related TNDM during remission. We identified fluctuations in ß-cell function and insulin resistance during remission.

In vivo efficacy of combination therapy with albendazole and atovaquone against primary hydatid cysts in mice.

Alveolar echinococcosis (AE) is caused by the larval stage of Echinococcus multilocularis. Chemotherapy for AE involves albendazole (ABZ), which has shown insufficient efficacy. More effective chemotherapy for AE is needed. Previously, we have demonstrated that atovaquone (ATV), an antimalarial, inhibits mitochondrial complex III of E. multilocularis and restricts the development of larval cysts in in vivo experiments. Therefore, in this study, we evaluated the efficacy of ABZ and ATV combination therapy on E. multilocularis in culture and in vivo experiments. Protoscoleces were treated with 50 µM ABZ and/or ATV in the medium; the duration of parasite elimination was determined under aerobic and anaerobic culture. In the in vivo experiment, the effects of ABZ and ATV combination treatment in BALB/c mice infected orally with eggs from the feces of an adult-stage E. multilocularis-infected dog were compared with those of standard oral ABZ therapy. In the culture assay, the duration of elimination associated with ABZ and ATV combination treatment was shorter than that associated with ATV alone under aerobic conditions. Protoscolex viability progressively reduced owing to the combination treatment under anaerobic conditions; however, either drug used singly did not exhibit antiparasitic effects under hypoxia. Furthermore, compared with ABZ alone, the combination treatment significantly reduced the growth of the primary cyst in the liver of mice infected orally with parasite eggs (P = .011). ATV enhances the effect of ABZ in the treatment of AE in mice.

Effect of the anti-parasitic compounds pyrvinium pamoate and artemisinin in enzymatic and culture assays: Data on the search for new anti-echinococcal drugs.

The dataset presented herein is related to a previous research article titled "Mitochondrial Complex III in Larval Stage of Echinococcus multilocularis as a Potential Chemotherapeutic Target and in vivo Efficacy of Atovaquone Against Primary Hydatid Cysts" [1]. In this report, data were collected by screening drugs for echinococcosis. We investigated the inhibitory activities of artemisinin and pyrvinium pamoate against the mitochondrial respiratory enzymes in E. multilocularis protoscoleces. Artemisinin did not inhibit mitochondrial complexes I, II, and III. However, pyrvinium pamoate inhibited complex I at 11 µM, although complexes II and III were not inhibited. In the culture assay, E. multilocularis protoscoleces were treated with atovaquone (ATV), rotenone, praziquantel, artemisinin, and pyrvinium pamoate at a final concentration of 50 µM in different culture media. The viability of protoscoleces was compared under aerobic and anaerobic conditions via culture experiments. The survival days of E. multilocularis protoscoleces were evaluated in the drug-treated group compared with those in the non-treated group. The results of these culture assays revealed that praziquantel and artemisinin did not eliminate the protoscoleces under both aerobic and anaerobic conditions. However, a stronger elimination ability was observed with the co-administration of praziquantel or artemisinin with ATV than with ATV alone under aerobic conditions. Pyrvinium pamoate completely killed protoscoleces at 5 and 7 days under aerobic and anaerobic conditions, respectively. Pyrvinium pamoate behaved identically to rotenone, the complex I inhibitor, in the culture treatment assay. The data serve as a reference for the development of novel anti-echinococcal drugs.

Mitochondrial complex III in larval stage of Echinococcus multilocularis as a potential chemotherapeutic target and in vivo efficacy of atovaquone against primary hydatid cysts.

Echinococcus multilocularis employs aerobic and anaerobic respiration pathways for its survival in the specialized environment of the host. Under anaerobic conditions, fumarate respiration has been identified as a promising target for drug development against E. multilocularis larvae, although the relevance of oxidative phosphorylation in its survival remains unclear. Here, we focused on the inhibition of mitochondrial cytochrome bc1 complex (complex III) and evaluated aerobic respiratory activity using mitochondrial fractions from E. multilocularis protoscoleces. An enzymatic assay revealed that the mitochondrial fractions possessed NADH-cytochrome c reductase (mitochondrial complexes I and III) and succinate-cytochrome c reductase (mitochondrial complexes II and III) activities in the aerobic pathway. Enzymatic analysis showed that atovaquone, a commercially available anti-malarial drug, inhibited mitochondrial complex III at 1.5 nM (IC50). In addition, culture experiments revealed the ability of atovaquone to kill protoscoleces under aerobic conditions, but not under anaerobic conditions, indicating that protoscoleces altered their respiration system to oxidative phosphorylation or fumarate respiration depending on the oxygen supply. Furthermore, combined administration of atovaquone with atpenin A5, a quinone binding site inhibitor of complex II, completely killed protoscoleces in the culture. Thus, inhibition of both complex II and complex III was essential for strong antiparasitic effect on E. multilocularis. Additionally, we demonstrated that oral administration of atovaquone significantly reduced primary alveolar hydatid cyst development in the mouse liver, compared with the untreated control, indicating that complex III is a promising target for development of anti-echinococcal drug.

Case of an infant with hepatic cirrhosis caused by mitochondrial respiratory chain disorder.

The patient had hepatomegaly with liver dysfunction at the age of 1 month. Magnetic resonance imaging performed at the age of 1 year showed multiple nodules of varying size in his liver. We were able to examine the mitochondrial respiratory chain function in the liver biopsy samples because all other differential diagnoses for hepatic cirrhosis had been ruled out. Complex I and IV activities were below the normal level (<30%) of the citrate synthase (CS) ratio. Liver blue native polyacrylamide gel electrophoresis showed an extremely weak complex I and IV band. Liver respiratory chain complexes I and IV were found to be deficient in this patient. The histologic findings were highly suggestive of mitochondrial respiratory chain disorder. Findings of progressive liver cirrhosis changes were observed in magnetic resonance imaging at the age of 5 years. An examination of the mitochondrial respiratory chain function should be performed along with a liver biopsy if mitochondrial respiratory chain disorder is suspected as a possible differential diagnosis of idiopathic hepatitis.

[A case of disseminated BCG infection found during treatment of an infant with Crohn's disease].

Bloody stools, diarrhea and perianal abscesses were observed from the age of two months infant. The boy received a BCG vaccination at the age of four months. The patient was diagnosed as having Crohn's disease at the age of six months by intestinal endoscopy. Based on the diagnosis, he was treated with nutrition therapy, salazosulfapyridine, and prednisolone. Fever of unknown origin occurred two months after he had taken azathioprine at the age of two years and two months. Mycobacterium tuberculosis was detected from a gastric aspirate, and he was diagnosed as having disseminated BCG infection by means of the multiplex PCR method. Chest CT showed miliary pulmonary nodules in both lungs on admission. Physical examination revealed enlarged lymphnodes, which were palpable around the neck and groin, and hepatomegaly. Laboratory data were within normal ranges except a slightly increased peripheral white blood cell and serum CRP level. He was treated with rifampicin (15 mg/kg/day), isoniazid (15 mg/kg/day) for 12 months, and streptomycin (25 mg/kg/day) for two months. He became afebrile a week after starting the treatment, and the miliary pulmonary nodules in both lungs had disappeared by 5 months after starting the treatment. An abnormality of the NEMO gene, which is the gene responsible for ectodermal dysplasia and immunodeficiency, was identified at the age of three years. It is assumed that an abnormality of the NEMO gene caused a latent BCG infection over a period of one year and ten months, and immunosuppressive medicine (azathioprine) induced a disseminated BCG infection. This case report supports that anti-tuberculosis medicine should be given to prevent disseminated BCG infection if an infant who receive immunosuppressive therapy is found to have an immune deficiency characterized by a mycobacterium infection after BCG vaccination.