Functional and structural analysis of AT-specific minor groove binders that disrupt DNA–protein interactions and cause disintegration of the Trypanosoma brucei kinetoplast

Trypanosoma brucei, the causative agent of sleeping sickness (Human African Trypanosomiasis, HAT), contains a kinetoplast with the mitochondrial DNA (kDNA), comprising of >70% AT base pairs. This has prompted studies of drugs interacting with AT-rich DNA, such as the N-phenylbenzamide bis(2-aminoimidazoline) derivatives 1 [4-((4,5-dihydro-1H-imidazol-2-yl)amino)-N-(4-((4,5-dihydro-1H-imidazol-2-yl)amino)phenyl)benzamide dihydrochloride] and 2 [N-(3-chloro-4-((4,5-dihydro-1H-imidazol-2-yl)amino)phenyl)-4-((4,5-dihydro-1H-imidazol-2-yl)amino)benzamide] as potential drugs for HAT. Both compounds show in vitro effects against T. brucei and in vivo curative activity in a mouse model of HAT. The main objective was to identify their cellular target inside the parasite. We were able to demonstrate that the compounds have a clear effect on the S-phase of T. brucei cell cycle by inflicting specific damage on the kinetoplast. Surface plasmon resonance (SPR)–biosensor experiments show that the drug can displace HMG box-containing proteins essential for kDNA function from their kDNA binding sites. The crystal structure of the complex of the oligonucleotide d[AAATTT]2 with compound 1 solved at 1.25 Å (PDB-ID: 5LIT) shows that the drug covers the minor groove of DNA, displaces bound water and interacts with neighbouring DNA molecules as a cross-linking agent. We conclude that 1 and 2 are powerful trypanocides that act directly on the kinetoplast, a structure unique to the order Kinetoplastida

Efficacy of anthelminthic drugs and drug combinations against soil-transmitted helminths: a systematic review and network meta-analysis.

Background: Periodic mass distribution of benzimidazole anthelminthic drugs is the key strategy to control soil-transmitted helminths (STH) globally. However, benzimidazoles have low efficacy against Trichuris trichiura, and there are concerns about benzimidazole resistance potentially emerging in humans. Therefore, identifying alternative drug regimens is a pressing priority. We present a systematic review and network meta-analysis, comparing the efficacy of 21 different anthelminthic drug regimens, including standard, novel, and combination treatments. Methods: We searched PubMed, MEDLINE, Embase, Web of Science, and Cochrane databases and identified studies comparing anthelminthic treatments to each other or placebo. The outcomes calculated were relative risk (RR) of cure and difference in egg reduction rates (dERR). We used an automated generalized pair-wise modelling framework to generate mixed treatment effects against a common comparator, the current standard treatment (single-dose albendazole). This study is registered with PROSPERO (CRD42016050739). Findings: Our search identified 4876 studies, of which 114 were included in meta-analysis. Results identified several drug combinations with higher efficacy than single-dose albendazole for T. trichiura, including albendazole-ivermectin (RR of cure 3.22, 95%CI 1.84-5.63; dERR 0.97, 95%CI 0.21-1.74), albendazole-oxantel pamoate (RR 5.07, 95%CI 1.65-15.59; dERR 0.51, 95%CI 0.450-0.52), mebendazole-ivermectin (RR 3.37, 95%CI 2.20-5.16), and tribendimidine-oxantel pamoate (RR 4.06, 95%CI 1.30-12.64). Interpretation: There are several promising drug combinations that may enhance the impact of STH control programs on T. trichiura, without compromising efficacy against A. lumbricoides and hookworm. We suggest further, large-scale trials of these drug combinations and consideration of their use in STH control programs where T. trichiura is present

マンソン住血吸虫症流行地域の低強度感染に対する組換えタンパク抗原serpin，RP26を用いた抗体検出法の有用性

Schistosomiasis remains a worldwide public health problem, especially in sub-Saharan Africa. The World Health Organization targets the goal for its elimination as a public health problem in the 2030 Neglected Tropical Diseases (NTDs) Roadmap. Concerted action and agile responses to challenges will be necessary to achieve the targets. Better diagnostic tests can accelerate progress towards the elimination by monitoring disease trends and evaluating the effectiveness of interventions; however, current examinations such as Kato–Katz technique are of limited power to detect light-intensity infections. The point-of-care circulating cathodic antigen (POC-CCA) test shows a higher sensitivity compared to the reference standard, Kato-Katz technique, but it still lacks sufficient sensitivity with low infection intensity. In this study, we examined antibody reactions against recombinant protein antigens; Schistosoma mansoni serine protease-inhibitor (SmSerpin) and RP26, by enzyme-linked immunosorbent assay (ELISA) in plasma samples with light-intensity infection. The sensitivity using the cocktail antigen of recombinant SmSerpin and RP26 showed 83.7%. The sensitivity using S. mansoni soluble egg antigen (SmSEA) was 90.8%, but it showed poor specificity (29.7%), while the cocktail antigen presented improved specificity (61.4%). We conclude that antibody detection to the SmSerpin and RP26 protein antigens is effective to detect S. mansoni light-intensity infections. Our study indicates the potential of detecting antibody against recombinant protein antigens to monitor the transmission of schistosomiasis in low endemicity contexts.長崎大学学位論文 学位記番号:博(医歯薬)甲第1356号 学位授与年月日:令和3年6月2日Author: Mio Tanaka, Anna O. Kildemoes, Evans Asena Chadeka, Benard Ngetich Cheruiyot, Miho Sassa, Taeko Moriyasu, Risa Nakamura, Mihoko Kikuchi, Yoshito Fujii, Claudia J. de Dood, Paul L.A.M. Corstjens, Satoshi Kaneko, Haruhiko Maruyama, Sammy M. Njenga, Remco de Vrueh, Cornelis H. Hokke, Shinjiro HamanoCitation: Parasitology International, 83, art.102346; 2021Nagasaki University (長崎大学)課程博