Biology subjects

Sakanari, J.

Publications and source records attributed to Sakanari, J..

6 recordsLinked to original sources

bioRxiv2025

Fexinidazole and Corallopyronin A target Wolbachia-infected sheath cells present in filarial nematodes

The discovery of the endosymbiotic bacteria Wolbachia as an obligate symbiont of filarial nematodes has led to antibiotic-based treatments for filarial diseases. While lab and clinical studies have yielded promising results, recent animal studies reveal that Wolbachia levels may rebound following treatment with suboptimal doses of the antibiotic rifampicin. Previous work showed that a likely source of the bacterial rebound in females were dense clusters of Wolbachia in ovarian tissue. The number, size, and density of these Wolbachia clusters were not diminished despite antibiotic treatment. Here we define the cellular characteristics of the Wolbachia clusters in Brugia pahangi (wBp) and identify drugs that also target them. We have evidence that the Wolbachia clusters originate from newly formed sheath cells adjacent to the ovarian Distal Tip Cells. The dramatically enlarged volume of an infected sheath cell is strikingly similar to endosymbiont-induced bacteriocytes found in many insect species. Ultrastructural analysis reveals that the clustered Wolbachia present within the sheath cells exhibit a distinct morphology and form direct connections with the oocyte membrane and possibly the cytoplasm. This includes membrane-based channels providing a connection between Wolbachia-infected sheath cells and oocytes. We also determined that the Wolbachia within the sheath cells are either quiescent or replicating at a very low rate. Screens of known antibiotics and other drugs revealed that two drugs, Fexinidazole and Corallopyronin A, significantly reduced the number of clustered Wolbachia located within the sheath cells.

pathology↗

bioRxiv2023

Discovery of New Broad-Spectrum Anti-Infectives for Eukaryotic Pathogens Using Bioorganometallic Chemistry

Drug resistance observed with many anti-infectives clearly highlights the need for new broad-spectrum agents to treat especially neglected tropical diseases (NTDs) caused by eukaryotic parasitic pathogens including fungal infections. Since these diseases target the most vulnerable communities who are disadvantaged by health and socio-economic factors, new agents should be, if possible, easy-to-prepare to allow for commercialization based on their low cost. In this study, we show that simple modification of one of the most well-known antifungal drugs, fluconazole, with organometallic moieties not only improves the activity of the parent drug but also broadens the scope of application of the new derivatives. These compounds were highly effective in vivo against pathogenic fungal infections and potent against parasitic worms such as Brugia, which causes lymphatic filariasis and Trichuris, one of the soil-transmitted helminths that infects millions of people globally. Notably, the identified molecular targets indicate a mechanism of action that differs greatly from the parental antifungal drug, including targets involved in biosynthetic pathways that are absent in humans, offering great potential to expand our armamentarium against drug-resistant fungal infections and NTDs targeted for elimination by 2030. Overall, the discovery of these new compounds with broad-spectrum activity opens new avenues for the development of treatments for several current human infections, either caused by fungi or by parasites, including other NTDs, as well as newly emerging diseases. ONE-SENTENCE SUMMARYSimple derivatives of the well-known antifungal drug fluconazole were found to be highly effective in vivo against fungal infections, and also potent against the parasitic nematode Brugia, which causes lymphatic filariasis and against Trichuris, one of the soil-transmitted helminths that infects millions of people globally.

pharmacology and toxicology↗

bioRxiv2023

Uncovering the essential roles of human GCP 2 orthologs in Caenorhabditis elegans.

Human glutamate carboxypeptidase 2 (GCP2) from the M28B metalloprotease group is an important target for therapy in neurological disorders and an established tumor marker. However, its physiological functions remain unclear. To better understand general roles, we used the model organism Caenorhabditis elegans genetically manipulate its three existing orthologous genes and evaluate the impact on worm physiology. The results of gene knockout studies showed that C. elegans GCP2 orthologs affect the pharyngeal physiology, reproduction, and structural integrity of the organism. Promoter-driven GFP expression revealed distinct localization for each of the three gene paralogs, with gcp-2.1 being most abundant in muscles, intestine, and pharyngeal interneurons, gcp-2.2 restricted to the phasmid neurons, and gcp-2.3 located in the excretory cell. This study provides new insight into the unique phenotypic effects of GCP2 gene knockouts in C. elegans, and the specific tissue localizations. We believe that elucidation of particular roles in a non-mammalian organism can help to explain important questions linked to human GCP2 physiology and in extension to GCP2 involvement in pathophysiological processes.

biochemistry↗

bioRxiv2019

De novo identification of toxicants that cause irreparable damage to parasitic nematode intestinal cells

Efforts to identify new drugs for therapeutic and preventive treatments against parasitic nematodes have gained increasing interest with expanding pathogen omics databases and drug databases from which new anthelmintic compounds might be identified. Here, a novel approach focused on integrating a pan-Nematoda multi-omics data targeted to a specific nematode organ system (the intestinal tract) with evidence-based filtering and chemogenomic screening was undertaken. Based on de novo computational target prioritization of the 3,564 conserved intestine genes in A. suum, exocytosis was identified as a high priority pathway, and predicted inhibitors of exocytosis were tested using the large roundworm (Ascaris suum larval stages), a filarial worm (Brugia pahangi adult and L3), a whipworm (Trichuris muris adult), and the non-parasitic nematode Caenorhabditis elegans. 10 of 13 inhibitors were found to cause rapid immotility in A. suum L3 larvae, and five inhibitors were effective against the three phylogenetically diverse parasitic nematode species, indicating potential for a broad spectrum anthelmintics. Several distinct pathologic phenotypes were resolved related to molting, motility, or intestinal cell and tissue damage using conventional and novel histologic methods. Pathologic profiles characteristic for each inhibitor will guide future research to uncover mechanisms of the anthelmintic effects and improve on drug designs. This progress firmly validates the focus on intestinal cell biology as a useful resource to develop novel anthelmintic strategies. Author summaryThe intestinal cells of parasitic nematodes are not known to regenerate, therefore disruption of essential processes that cause irreparable damage to intestinal cells is expected to promote worm expulsion. To facilitate improved methods of therapy we need to better understand the basic intestinal cell and tissue functions of this critical organ. To that end have undertaken a comprehensive analysis of multi-omics omics data and identify and prioritize intestinal genes/pathways with essential functions and associated drugs and established a foundational model of the STH intestinal system using the large roundworm Ascaris suum to test and validate inhibitors of these functions. We found 10 inhibitors to impacted motility, and seven of those showed severe pathology and an apparent irreparable damage to intestinal cells. Furthermore, five inhibitors were effective against the three phylogenetically diverse parasitic nematode species, indicating potential for a broad spectrum anthelmintics. Our results firmly validate the focus on intestinal cell biology as a useful resource to develop novel anthelmintic strategies.

pathology↗

bioRxiv2019

Chagas disease serological test performance in United States blood donor specimens

BackgroundChagas disease affects an estimated 300,000 individuals in the US. Diagnosis in the chronic phase requires positive results by two different IgG serological tests. Three ELISAs (Hemagen, Ortho, Wiener) and one rapid test (InBios) are FDA-cleared, but comparative data in US populations are sparse.\n\nMethodsWe evaluated 500 seropositive and 300 seronegative blood donor plasma samples. Country of birth was known for 255 seropositive specimens and grouped into regions: Mexico (n=94), Central America (n=88) and South America (n=73). Specimens were tested by the four FDA-cleared IgG serological assays. Test performance was evaluated by two comparators and latent class analysis.\n\nResultsInBios had the highest sensitivity (97.4-99.3%), but lowest specificity (87.5-92.3%). Hemagen had the lowest sensitivity (88.0-92.0%), but high specificity (99.0-100.0%). Sensitivity was intermediate for Ortho (92.4-96.5%) and Wiener (94.0-97.1%); both had high specificity (98.8-100.0% and 96.7-99.3%, respectively). Antibody reactivity and clinical sensitivity was lowest in donors from Mexico, intermediate in those from Central America and highest in those from South America.\n\nConclusionsOur findings provide an initial evidence base to improve laboratory diagnosis of Chagas disease in the US. The best current testing algorithm would employ a high sensitivity screening test followed by a high specificity confirmatory test.

microbiology↗

bioRxiv2018

Repurposing the quinoline antibiotic nitroxoline to treat infections caused by the brain-eating amoeba Balamuthia mandrillaris

Balamuthia mandrillaris is a pathogenic free-living amoeba that causes a rare but almost always fatal infection of the central nervous system called granulomatous amoebic encephalitis (GAE). Two distinct forms of B. mandrillaris - a proliferative trophozoite form and a non-proliferative cyst form, which is highly resistant to harsh physical and chemical conditions - have been isolated from environmental samples worldwide and are both observed in infected tissue. Patients suffering from GAE are typically treated with aggressive and prolonged multi-drug regimens often including the antimicrobial agents miltefosine and pentamidine isethionate. However, survival rates remain low and studies evaluating the susceptibility of B. mandrillaris to these compounds and other potential therapeutics are limited. To address the need for more effective treatments, we screened 2,177 clinically-approved compounds for in vitro activity against B. mandrillaris. The quinoline antibiotic nitroxoline, which has safely been used in humans to treat urinary tract infections, was identified as a lead compound. We show that nitroxoline inhibits both trophozoites and cysts at low micromolar concentrations, which are within a physiologically relevant range. We compare the in vitro efficacy of nitroxoline to drugs currently used in the standard of care for GAE and find that nitroxoline is the most potent and selective inhibitor of B. mandrillaris tested. Furthermore, we demonstrate that nitroxoline prevents B. mandrillaris-mediated destruction of host cells in cultured fibroblast and primary brain explant models also at physiologically relevant concentrations. Together, our findings indicate that nitroxoline is a promising candidate for repurposing as a novel treatment of B. mandrillaris infections.\n\nImportanceBalamuthia mandrillaris is responsible for hundreds of reported cases of amoebic encephalitis, the majority of which have been fatal. Despite being an exceptionally deadly pathogen, B. mandrillaris is understudied, leaving many open questions regarding epidemiology, diagnosis, and treatment. Due to the lack of effective drugs to fight B. mandrillaris infections, mortality rates remain high even for patients receiving intensive care. This study addresses the need for new anti-amoebic drugs using a high-throughput screening approach to identify novel B. mandrillaris inhibitors. The most promising candidate identified was the quinoline antibiotic nitroxoline, which has a long history of safe use in humans. We show that nitroxoline kills B. mandrillaris at physiologically relevant concentrations and exhibits greater potency and selectivity than drugs commonly used in the current standard of care. The findings we present demonstrate the potential of nitroxoline to be an important new tool in the treatment of life threatening B. mandrillaris infections.

pharmacology and toxicology↗