Biology subjects

Haeberlein, S.

Publications and source records attributed to Haeberlein, S..

5 recordsLinked to original sources

bioRxiv2026

G protein-coupled receptor SmGPCR9 interacts with neuropeptides and controls spermatogenesis in Schistosoma mansoni

Schistosomiasis is a neglected tropical disease caused by parasitic flatworms of the genus Schistosoma, impacting hundreds of millions of people and animals globally. Disease pathology primarily originates from host immune responses to parasite eggs, which are produced only when female schistosomes are continuously paired with males. Past research focused on pairing-dependent female sexual maturation, while scarce data exist for the males reproductive biology. In this study, we characterized the G protein-coupled receptor Smgpcr9 (Smp_244240), an orphan Class A (Rhodopsin-like) GPCR with a testis-preferential and pairing-influenced expression profile in S. mansoni males. Previous bulk RNA-seq analyses of adult worms and their isolated gonads revealed that Smgpcr9 belongs to a subgroup of GPCR genes with abundant testis-preferential and pairing-influenced transcript levels in males but low and extremely low expression in unpaired and paired females, respectively. This male-/unpaired female-biased expression pattern mirrors that of neuropeptide (npp) genes of S. mansoni such as Smnpp26 and Smnpp41. In a deorphanization approach using yeast-two-hybrid analyses, GPCR internalization experiments, bioluminescence resonance energy transfer assays, and by modeling and docking analyses, we provide first evidence that both NPPs can interact with SmGPCR9. Furthermore, we optimized a GPCR RNAi approach and achieved efficient transcript knockdown (> 90%) enabling robust functional characterization of Smgpcr9. Following RNAi, physiological and morphological analyses revealed that SmGPCR9 regulates key aspects of male reproductive biology like testis morphology and spermatogenesis. Remarkably, ovary structure and egg production were also affected in paired females post RNAi. We observed similar phenotypes plus motility constraints and reduced stem-cell proliferation in both sexes upon RNAi of Smnpp26 and Smnpp41. In all cases, RNAi downstream analyses by RT-qPCR of marker genes substantiated the observed phenotypic effects. These results strongly indicate the importance of SmGPCR9, SmNPP26, and SmNPP41 for spermatogenesis and further physiological processes in male and female S. mansoni. Author SummaryResearch of the reproductive biology of schistosomes focused mainly on females so far, which upon pairing sexually mature to produce eggs that are important for the life cycle maintenance but also for the pathogenesis of schistosomiasis, the infectious disease caused by these parasites. We investigated a yet unknown G protein-coupled receptor, Smgpcr9, which showed a testis-preferential and pairing-influenced expression profile in Schistosoma mansoni males. To this end, we optimized an RNA interference (RNAi) approach for knockdown analysis, identified neuropeptides (NPPs) as potential ligands by different biochemical approaches and modeling and docking analyses, and we investigated the roles of SmGPCR9 and two interacting NPPs, SmNPP26 and SmNPP41, by physiological, microscopical, and molecular techniques. Our results strongly suggest that SmGPCR9 and both NPPs regulate spermatogenesis. Furthermore, we detected effects on ovary morphology, egg production, and stem-cell proliferation of paired females post RNAi. Taken together, we deorphanized SmGPCR9 and showed for the first time the essential role of a so far uncharacterized GPCR and two interacting neuropeptides for spermatogenesis. Our results shed first light on spermatogenesis regulatory processes controlled by GPCRs and neuropeptides in male S. mansoni and thus expand our understanding of the roles of GPCR-NPP signaling for schistosome reproductive biology.

molecular biology↗

bioRxiv2025

Host-specific platelet-activating factor acetylhydrolase selectively remodels diacylglycerophospholipids to control schistosome development

BackgroundSchistosomiasis, a major neglected tropical disease, is currently treated with only one drug, praziquantel (PZQ), effective only against adult worms. However, high reinfection rates and potential development of drug resistance following widespread use of PZQ emphasize the need for a deeper molecular understanding of the host-parasite crosstalk as a basis for urgently needed novel drugs. Here, we identify and characterize a soluble host-derived schistosomicidal phospholipase that influences the diacylglycerophospholipid metabolism and, thereby, the survival and development of Schistosoma mansoni. MethodsLarge-scale proteomic screening identified host platelet-activating factor acetylhydrolase (PAFAH) as a potential schistosomicidal factor. Ultra-performance tandem mass spectrometry and electron microscopy imaging were employed to demonstrate the relevance and the lethal effects of recombinant expressed mouse PAFAH (MsPAFAH) on all juvenile stages and adult parasites from a mouse model of schistosomiasis. Quantitative lipidomic analysis revealed MsPAFAH-impaired glycerophospholipid distribution and metabolism and following free fatty acid supplementation. ResultsMsPAFAH was upregulated in schistosome-infected mice and exhibited potent schistosomicidal activity against all parasite life stages ex vivo. In contrast, human PAFAH had no effect on parasite viability. MsPAFAH treatment led to profound impairments in worm fecundity, pairing stability, reproductive organ integrity, and stem cell development. This activity was associated with substantial sex-dependent changes in ether-phospholipid composition and distribution within the schistosome tegument. MsPAFAH specifically decreased the availability of phospholipid species containing unsaturated fatty acids, namely eicosenoic (20:1) and docosatetraenoic acid (22:4), while increasing levels of respective hydrolysis (lyso) products of diacyl- and ether-phospholipids (carrying 20:1 or stearic acid (18:0)), predominantly in males. Supplementation of metabolized fatty acids C20:1/eicosenoic acid and 22:4/adrenic acid rescued the viability of female worms, confirming the essential role of the metabolism of these diacylglycerophospholipids in schistosome survival. ConclusionsThese findings unravel how a host phospholipase interferes with schistosome biology and development by regulating diacylglycerophospholipid availability and can thus open new avenues for schistosomiasis drug development and control.

systems biology↗

bioRxiv2024

Single-cell transcriptomics identifies a p21-activated kinase important for survival of the zoonotic parasite Fasciola hepatica

Knowledge on the cell types and cell-specific gene expression of multicellular pathogens facilitates drug discovery and allows gaining a deeper understanding of pathogen biology. By utilizing single-cell RNA sequencing (scRNA-seq), we analyzed 19,581 cells of a globally prevalent parasitic flatworm, the liver fluke Fasciola hepatica, which causes a neglected tropical disease and zoonosis known as fascioliasis. We identified 15 distinct clusters, including cells of the reproductive tract and gastrodermis, and report the identification and transcriptional characterization of potential differentiation lineages of stem cells within this parasite. Furthermore, a previously unrecognized ELF5- and TRPMPZQ-expressing muscle cell type was discovered, characterized by high expression of protein kinases. Among these, the p21-activated kinase PAK4 was essential for parasite survival. These data provide novel insight into the cellular composition of a complex multicellular parasite and demonstrate how gene expression at single-cell resolution can serve as a resource for the identification of new drug targets.

molecular biology↗

bioRxiv2023

Spatial transcriptomics of a parasitic flatworm provides a molecular map of vaccine candidates, drug targets and drug resistance genes

The spatial organization of gene expression dictates tissue functions in multicellular parasites. Here, we present the first spatial transcriptome of a parasitic flatworm, the common liver fluke Fasciola hepatica. We identified gene expression profiles and marker genes for eight distinct tissues and validated the latter by in situ hybridization. To demonstrate the power of our spatial atlas, we focused on genes with substantial medical importance, including vaccine candidates (Ly6 proteins), drug targets ({beta}-tubulins, protein kinases) and drug resistance genes (glutathione S-transferases, ABC transporters). Several of these genes exhibited unique expression patterns, indicating tissue-specific biological functions. Notably, the prioritization of tegumental protein kinases identified a PKC{beta}, for which small-molecule targeting caused parasite death. Our comprehensive gene expression map provides unprecedented molecular insights into the organ systems of this complex parasitic organism, serving as a valuable tool for both basic and applied research.

molecular biology↗

bioRxiv2023

Target-based discovery of a broad spectrum flukicide

Diseases caused by parasitic flatworms impart a considerable healthcare burden worldwide. Many of these diseases - for example, the parasitic blood fluke infection, schistosomiasis - are treated with the drug praziquantel (PZQ). However, PZQ is ineffective against disease caused by liver flukes from the genus Fasciola. This is due to a single amino acid change within the target of PZQ, a transient receptor potential ion channel (TRPMPZQ), in Fasciola species. Here we identify benzamidoquinazolinone analogs that are active against Fasciola TRPMPZQ. Structure-activity studies define an optimized ligand (BZQ) that caused protracted paralysis and damage to the protective tegument of these liver flukes. BZQ also retained activity against Schistosoma mansoni comparable to PZQ and was active against TRPMPZQ orthologs in all profiled species of parasitic fluke. This broad spectrum activity was manifest as BZQ adopts a pose within the binding pocket of TRPMPZQ dependent on a ubiquitously conserved residue. BZQ therefore acts as a universal activator of trematode TRPMPZQ and a first-in-class, broad spectrum flukicide.

microbiology↗