Smp38 MAP Kinase Regulation in Schistosoma mansoni: Roles in Survival, Oviposition, and Protection Against Oxidative Stress

Whole-genomic comparison reveals complex population dynamics and parasitic adaptation of Echinococcus granulosus sensu stricto

Cystic echinococcosis (CE), caused by Echinococcus granulosus sensu stricto (s.s.), poses a substantial risk to both humans and domestic animals globally. Here, we compared the whole genomes of 111 E. granulosus s.s. samples from China. Genomic variation data revealed frequent cross-fertilization in the hermaphroditic E. granulosus. The G1 and G3 genotypes represent distinct mitochondrial lineages, while showing no differentiation in the nuclear genome, suggesting mito-nuclear discordance caused by historical geographic separation and subsequent fusion. Population structure, demographic history, and gene flow among populations reflected the transmission route of E. granulosus s.s. from the Middle East to Qinghai-Xizang Plateau through the migration of nomadic people, followed by introgression during secondary contact. Genomic variations highlighted selection signatures within the genome prone to balancing selection, particularly impacting genes encoding membrane-related proteins, representing a potential evolutionary strategy for adaptation to parasitic life. Balancing selection pressure on the gene-coding sodium/bile acid cotransporter led to its high level of genetic stability, which may play a crucial role in the survival and development of E. granulosus during the parasitic stage, making it a potential drug target for the treatment of CE. Meanwhile, other genomic regions under strong balancing selection may provide potential targets for protective immunity. These findings offer valuable insights into the complex dynamics and adaptive evolution of E. granulosus s.s. in China.IMPORTANCEEchinococcus granulosus sensu stricto (s.s.) is the primary cause of cystic echinococcosis (CE), a parasitic disease affecting humans and livestock with significant health and economic impacts. Previous studies on this parasite relied on mitochondrial DNA to classify its genotypes and understand its genetic diversity. However, these studies cannot capture the full complexity of its evolutionary dynamics and adaptation strategies. Our research employs comprehensive genome-wide sequencing, offering a more nuanced view of its genetic landscape. We discovered that cross-fertilization appears to be a prevalent reproductive strategy in the hermaphroditic E. granulosus, underpinning the observed deep mitochondrial divergence between genotypes G1 and G3, as well as gene flow among populations. The transmission history of E. granulosus s.s. in China and its widespread genetic mixing were likely facilitated by the migrations of nomadic peoples. Furthermore, we identified genes under balancing selection, including the gene involved in the uptake of host bile acids, which play a crucial role in the parasite's survival and development, potentially offering new targets for intervention. Our research advances the understanding of the genetic diversity and evolutionary strategies of E. granulosus, laying the foundation for improved control measures of CE.

A reanalysis and integration of transcriptomics and proteomics datasets unveil novel drug targets for Mekong schistosomiasis

Schistosomiasis, caused by Schistosoma trematodes, is a significant global health concern, particularly affecting millions in Africa and Southeast Asia. Despite efforts to combat it, the rise of praziquantel (PZQ) resistance underscores the need for new treatment options. Protein kinases (PKs) are vital in cellular signaling and offer potential as drug targets. This study focused on focal adhesion kinase (FAK) as a candidate for anti-schistosomal therapy. Transcriptomic and proteomic analyses of adult S. mekongi worms identified FAK as a promising target due to its upregulation and essential role in cellular processes. Molecular docking simulations assessed the binding energy of FAK inhibitors to Schistosoma FAK versus human FAK. FAK inhibitor 14 and PF-03814735 exhibited strong binding to Schistosoma FAK with minimal binding for human FAK. In vitro assays confirmed significant anti-parasitic activity against S. mekongi, S. mansoni, and S. japonicum, comparable to PZQ, with low toxicity in human cells, indicating potential safety. These findings highlight FAK as a promising target for novel anti-schistosomal therapies. However, further research, including in vivo studies, is necessary to validate efficacy and safety before clinical use. This study offers a hopeful strategy to combat schistosomiasis and reduce its global impact.

Naringenin: its chemistry and roles in neuroprotection

According to epidemiological research, as the population ages, neurological illnesses are becoming a bigger issue. Despite improvements in the treatment of these diseases, there are still widespread worries about how to find a long-lasting remedy. Several neurological diseases can be successfully treated with natural substances. As a result, current research has been concentrated on finding effective neuroprotective drugs with improved efficacy and fewer side effects. Naringenin is one potential treatment for neurodegenerative diseases. Many citrus fruits, tomatoes, bergamots, and other fruits are rich in naringenin, a flavonoid. This phytochemical is linked to a variety of biological functions. Naringenin has attracted a lot of interest for its ability to exhibit neuroprotection through several mechanisms. In the current article, we present evidence from the literature that naringenin reduces neurotoxicity and oxidative stress in brain tissues. Also, the literatures that are currently accessible shows that naringenin reduces neuroinflammation and other neurological anomalies. Additionally, we found several studies that touted naringenin as a promising anti-amyloidogenic, antidepressant, and neurotrophic treatment option. This review's major goal is to reflect on advancements in knowledge of the molecular processes that underlie naringenin's possible neuroprotective effects. Furthermore, this article also provides highlights of Naringenin with respect to its chemistry and pharmacokinetics.

Identification of potent schistosomicidal compounds predicted as type II-kinase inhibitors against Schistosoma mansoni c-Jun N-terminal kinase SMJNK

Introduction

Schistosomiasis has for many years relied on a single drug, praziquantel (PZQ) for treatment of the disease. Immense efforts have been invested in the discovery of protein kinase (PK) inhibitors; however, given that the majority of PKs are still not targeted by an inhibitor with a useful level of selectivity, there is a compelling need to expand the chemical space available for synthesizing new, potent, and selective PK inhibitors. Small-molecule inhibitors targeting the ATP pocket of the catalytic domain of PKs have the potential to become drugs devoid of (major) side effects, particularly if they bind selectively. This is the case for type II PK inhibitors, which cause PKs to adopt the so-called DFG-out conformation, corresponding to the inactive state of the enzyme.

Methods

The goal was to perform a virtual screen against the ATP pocket of the inactive JNK protein kinase. After virtually screening millions of compounds, Atomwise provided 85 compounds predicted to target c-Jun N-terminal kinase (JNK) as type II inhibitors. Selected compounds were screened in vitro against larval stage (schistosomula) of S. mansoni using the XTT assay. Adult worms were assessed for motility, attachment, and pairing stability. Active compounds were further analyzed by molecular docking against SmJNK.

Results

In total, 33 compounds were considered active in at least one of the assays, and two compounds were active in every in vitro screening assay. The two most potent compounds presented strong effects against both life stages of the parasite, and microscopy analysis showed phenotypic alterations on the tegument, in the gonads, and impairment of cell proliferation.

Conclusion

The approach to screen type II kinase inhibitors resulted in the identification of active compounds that will be further developed against schistosomiasis.

Human growth factor-mediated signalling through lipid rafts regulates stem cell proliferation, development and survival of Schistosoma mansoni

Although the mechanisms by which schistosomes grow and develop in humans are poorly defined, their unique outer tegument layer, which interfaces with host blood, is considered vital to homeostasis of the parasite. Here, we investigated the importance of tegument lipid rafts to the biology of Schistosoma mansoni in the context of host-parasite interactions. We demonstrate the temporal clustering of lipid rafts in response to human epidermal growth factor (EGF) during early somule development, concomitant with the localization of anteriorly orientated EGF receptors (EGFRs) and insulin receptors, mapped using fluorescent EGF/insulin ligand. Methyl-β-cyclodextrin (MβCD)-mediated depletion of cholesterol from lipid rafts abrogated the EGFR/IR binding at the parasite surface and led to modulation of protein kinase C, extracellular signal-regulated kinase, p38 mitogen-activated protein kinase and Akt signalling pathways within the parasite. Furthermore, MβCD-mediated lipid raft disruption, and blockade of EGFRs using canertinib, profoundly reduced somule motility and survival, and attenuated stem cell proliferation and somule growth and development particularly to the fast-growing liver stage. These findings provide a novel paradigm for schistosome development and vitality in the host, driven through host-parasite interactions at the tegument, that might be exploitable for developing innovative therapeutic approaches to combat human schistosomiasis.

Form and Function in the Digenea, with an Emphasis on Host-Parasite and Parasite-Bacteria Interactions

This review covers the general aspects of the anatomy and physiology of the major body systems in digenetic trematodes, with an emphasis on new knowledge of the area acquired since the publication of the second edition of this book in 2019. In addition to reporting on key recent advances in the morphology and physiology of tegumentary, sensory, neuromuscular, digestive, excretory, and reproductive systems, and their roles in host-parasite interactions, this edition includes a section discussing the known and putative roles of bacteria in digenean biology and physiology. Furthermore, a brief discussion of current trends in the development of novel treatment and control strategies based on a better understanding of the trematode body systems and associated bacteria is provided.

Reconstruction of the TGF-β signaling pathway of Fasciola gigantica

In the present study, we reconstructed the transforming growth factor beta (TGF-β) signaling pathway for Fasciola gigantica, which is a neglected tropical pathogen. We defined the components involved in the TGF-β signaling pathway and investigated the transcription profiles of these genes for all developmental stages of F. gigantica. In addition, the presence of these components in excretory and secretory products (FgESP) was predicted via signal peptide annotation. The core components of the TGF-β signaling pathway have been detected in F. gigantica; classical and nonclassical single transduction pathways were constructed. Four ligands have been detected, which may mediate the TGF-β signaling pathway and BMP signaling pathway. Two ligand-binding type II receptors were detected, and inhibitory Smad7 was not detected. TLP, BMP-3, BMP-1, and ActRIb showed higher transcription in 42-day juvenile and 70-day juvenile, while ActRIIa, Smad1, ActRIIb, Smad8, KAT2B, and PP2A showed higher transcription in egg. TLM, Ski, Smad6, BMPRI, p70S6K, Smad2, Smad3, TgfβRI, Smad4, and p300 showed higher transcription in metacercariae. Four ligands, 2 receptors and 3 Smads are predicted to be present in the FgESP, suggesting their potential extrinsic function. This study should help to understand signal transduction in the TGF-β signaling pathway in F. gigantica. In addition, this study helps to illustrate the complex mechanisms involved in developmental processes and F. gigantica - host interaction and paves the way for further characterization of the signaling pathway in trematodes.

Schistosoma mansoni excretory-secretory products induce protein kinase signalling, hyperkinesia, and stem cell proliferation in the opposite sex

Adult male and female schistosomes in copula dwell within human blood vessels and lay eggs that cause the major Neglected Tropical Disease human schistosomiasis. How males and females communicate to each other is poorly understood; however, male-female physical interaction is known to be important. Here, we investigate whether excretory-secretory products (ESPs), released into the external milieu by mature Schistosoma mansoni, might induce responses in the opposite sex. We demonstrate that ESPs adhere to the surface of opposite sex worms inducing the activation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (p38 MAPK) pathways, particularly in the parasite tegument. Furthermore, we show that mature worms stimulated signalling in juvenile worms. Strikingly, we demonstrate that ESPs from the opposite sex promote stem cell proliferation, in an ERK- and p38 MAPK-dependent manner, in the tegument and within the testes of males, and the ovaries and vitellaria of females. Hyperkinesia also occurs following opposite sex ESP exposure. Our findings support the hypothesis that male and female schistosomes may communicate over distance to modulate key processes underlying worm development and disease progression, opening unique avenues for schistosomiasis control.

Inhibition of signal peptidase complex expression affects the development and survival of Schistosoma japonicum

Background

Schistosomiasis, the second most neglected tropical disease defined by the WHO, is a significant zoonotic parasitic disease infecting approximately 250 million people globally. This debilitating disease has seriously threatened public health, while only one drug, praziquantel, is used to control it. Because of this, it highlights the significance of identifying more satisfactory target genes for drug development. Protein translocation into the endoplasmic reticulum (ER) is vital to the subsequent localization of secretory and transmembrane proteins. The signal peptidase complex (SPC) is an essential component of the translocation machinery and functions to cleave the signal peptide sequence (SP) of secretory and membrane proteins entering the ER. Inhibiting the expression of SPC can lead to the abolishment or weaker cleavage of the signal peptide, and the accumulation of uncleaved protein in the ER would affect the survival of organisms. Despite the evident importance of SPC, in vivo studies exploring its function have yet to be reported in S. japonicum.

Methods

The S. japonicum SPC consists of four proteins: SPC12, SPC18, SPC22 and SPC25. RNA interference was used to investigate the impact of SPC components on schistosome growth and development in vivo. qPCR and in situ hybridization were applied to localize the SPC25 expression. Mayer's carmalum and Fast Blue B staining were used to observe morphological changes in the reproductive organs of dsRNA-treated worms. The effect of inhibitor treatment on the worm's viability and pairing was also examined in vitro.

Results

Our results showed that RNAi-SPC delayed the worm's normal development and was even lethal for schistosomula in vivo. Among them, the expression of SPC25 was significantly higher in the developmental stages of the reproductive organs in schistosomes. Moreover, SPC25 possessed high expression in the worm tegument, testes of male worms and the ovaries and vitellarium of female worms. The SPC25 knockdown led to the degeneration of reproductive organs, such as the ovaries and vitellarium of female worms. The SPC25 exhaustion also reduced egg production while reducing the pathological damage of the eggs to the host. Additionally, the SPC-related inhibitor AEBSF or suppressing the expression of SPC25 also impacted cultured worms' pairing and viability in vitro.

Conclusions

These data demonstrate that SPC is necessary to maintain the development and reproduction of S. japonicum. This research provides a promising anti-schistosomiasis drug target and discovers a new perspective on preventing worm fecundity and maturation.

Hypoxanthine guanine phosphoribosyl transferases SmHGPRTases functional roles in Schistosoma mansoni

Introduction

Extracellular/environmental stimuli trigger cellular responses to allow Schistosoma sp. parasites adaptation and decide development and survival fate. In this context, signal transduction involving eukaryotic protein kinases (ePKs) has an essential role in regulatory mechanisms. Functional studies had shown the importance of MAPK pathway for Schistosoma mansoni development. In addition, early studies demonstrated that Smp38 MAPK regulates the expression of a large set of genes, among them the hypoxanthine-guanine phosphoribosyl transferase 1 (SmHGPRTase 1, Smp_103560), a key enzyme in the purine salvage pathway that is part of a family comprising five different proteins.

Methods

First, the regulation of this gene family by the MAPKs pathways was experimentally verified using Smp38-predicted specific inhibitors. In silico analysis showed significant differences in the predicted structure and the domain sequence among the schistosomal HGPRTase family and their orthologs in humans. In order to interrogate the HGPRTases (Smp_103560, Smp_148820, Smp_168500, Smp_312580 and Smp_332640, henceforth SmHGPRTase -1, -2, -3, -4, -5) functional roles, schistosomula, sporocysts, and adult worms were knocked-down using specific dsRNAs.

Results

Our results suggest that SmHGPRTases activity has an essential role in sporocysts and schistosomula development since significant differences in viability, size, and/ or shape were observed after the in vitro knockdown. Also, the knockdown of SmHGPRTases in schistosomula influenced the ovary development and egg maturation in female adult worms during mammalian infection. We also observed alterations in the movement of female adult worms knocked-down in vitro. Most of these results were shown when all gene family members were knocked-down simultaneously, suggesting a redundant function among them.

Discussion

Thus, this study helps to elucidate the functional roles of the SmHGPRTase gene family in the S. mansoni life cycle and provides knowledge for future studies required for schistosomiasis treatment and control.

SmTAL-9, a Member of the Schistosoma mansoni Tegument Allergen-Like Family, Is Important for Parasite Survival and a Putative Target for Drug/Vaccine Development

The tegument of Schistosoma mansoni is involved in essential functions for parasite survival and is known to stimulate immune responses in pre-clinical vaccine trials. Smtal-9, a member of the tegument-allergen-like (TAL) family, is one of the components of the tegument of schistosomula recognized by sera from immunized and protected mice. In this work, we assessed the role of Smtal-9 in parasite survival using the RNAi approach. Also, we cloned and expressed a recombinant form of Smtal-9 and evaluated its ability to induce protection in mice. Smtal-9 knockdown did not impact parasite survival in vitro, but significantly decreased schistosomula size. Additionally, significant reduction in both parasite and egg burdens were observed in mice inoculated with Smtal-9-knockdown schistosomula. Immunization using the Smtal-9 as an antigen conferred partial protection against challenge infection. Overall, our results indicate that Smtal-9 is a candidate target for drug and/or vaccine development due to its important role in parasite biology and survival.

Docking-Based Virtual Screening Enables Prioritizing Protein Kinase Inhibitors With In Vitro Phenotypic Activity Against Schistosoma mansoni

Schistosomiasis is a parasitic neglected disease with praziquantel (PZQ) utilized as the main drug for treatment, despite its low effectiveness against early stages of the worm. To aid in the search for new drugs to tackle schistosomiasis, computer-aided drug design has been proved a helpful tool to enhance the search and initial identification of schistosomicidal compounds, allowing fast and cost-efficient progress in drug discovery. The combination of high-throughput in silico data followed by in vitro phenotypic screening assays allows the assessment of a vast library of compounds with the potential to inhibit a single or even several biological targets in a more time- and cost-saving manner. Here, we describe the molecular docking for in silico screening of predicted homology models of five protein kinases (JNK, p38, ERK1, ERK2, and FES) of Schistosoma mansoni against approximately 85,000 molecules from the Managed Chemical Compounds Collection (MCCC) of the University of Nottingham (UK). We selected 169 molecules predicted to bind to SmERK1, SmERK2, SmFES, SmJNK, and/or Smp38 for in vitro screening assays using schistosomula and adult worms. In total, 89 (52.6%) molecules were considered active in at least one of the assays. This approach shows a much higher efficiency when compared to using only traditional high-throughput in vitro screening assays, where initial positive hits are retrieved from testing thousands of molecules. Additionally, when we focused on compound promiscuity over selectivity, we were able to efficiently detect active compounds that are predicted to target all kinases at the same time. This approach reinforces the concept of polypharmacology aiming for “one drug-multiple targets”. Moreover, at least 17 active compounds presented satisfactory drug-like properties score when compared to PZQ, which allows for optimization before further in vivo screening assays. In conclusion, our data support the use of computer-aided drug design methodologies in conjunction with high-throughput screening approach.

Comparative proteome analysis of the tegument of male and female adult Schistosoma mansoni

The tegument, as the surface layer of adult male and female Schistosoma spp. represents the protective barrier of the worms to the hostile environment of the host bloodstream. Here we present the first comparative analysis of sex-specific tegument proteins of paired or virgin Schistosoma mansoni. We applied a new and highly sensitive workflow, allowing detection of even low abundance proteins. Therefore, a streptavidin–biotin affinity purification technique in combination with single pot solid-phase enhanced sample preparation was established for subsequent LC–MS/MS analysis. We were able to identify 1519 tegument proteins for male and female virgin and paired worms and categorized them by sex. Bioinformatic analysis revealed an involvement of female-specific tegument proteins in signaling pathways of cellular processes and antioxidant mechanisms. Male-specific proteins were found to be enriched in processes linked to phosphorylation and signal transduction. This suggests a task sharing between the sexes that might be necessary for survival in the host. Our datasets provide a basis for further studies to understand and ultimately decipher the strategies of the two worm sexes to evade the immune system.

The Potential Role of MicroRNA‐124‐3p in Growth, Development, and Reproduction of Schistosoma japonicum

The microRNA‐124‐3p plays an important role in regulating development and neurogenesis. Previous microRNA sequencing analyses of Schistosoma japonicum revealed sja-miR-124-3p differential expression patterns in schistosomes from different hosts and at different developmental stages. This study explores the regulatory role of sja-miR-124-3p in S. japonicum development and reproduction. Quantitative reverse-transcription PCR (qRT-PCR) showed that the expression level of sja-miR-124-3p in S. japonicum from resistant hosts, such as Microtus fortis, and unsuitable hosts, such as rats and water buffalo, was significantly higher than that in mice and yellow cattle at the same developmental stage. Overexpressing sja-miR-124-3p in infected mice led to a hepatic egg reduction rate of 36.97%, smaller egg granulomas in the livers, increased liver weight, subsided hepatocyte necrosis, and diminished inflammatory cell infiltration. The width of female worms increased but decreased in males. The vitelline cells were irregular, swollen, or fused. The teguments and ventral sucker of males and females were swollen and broken, but the morphological changes were particularly notable in males. qRT-PCR and dual-luciferase reporter assay system were used to confirm the in-silico-predicted target genes, S. japonicum DEAD-box ATP-dependent RNA helicase 1 (sjDDX1) and DNA polymerase II subunit 2 (sjPOLE2). Our results showed that RNA interference (RNAi)-mediated sjDDX1 silencing in mice provided a 24.55% worm reduction rate and an 18.36% egg reduction rate, but the difference was not significant (p > 0.05). Thus, our findings suggest that sja-miR-124-3p has an important role in growth, development, and reproduction in S. japonicum. All these results will greatly contribute toward providing important clues for searching vaccine candidates and new drug targets against schistosomiasis.

Drug Repurposing and De Novo Drug Discovery of Protein Kinase Inhibitors as New Drugs against Schistosomiasis

Schistosomiasis is a neglected tropical disease affecting more than 200 million people worldwide. Chemotherapy relies on one single drug, praziquantel, which is safe but ineffective at killing larval stages of this parasite. Furthermore, concerns have been expressed about the rise in resistance against this drug. In the absence of an antischistosomal vaccine, it is, therefore, necessary to develop new drugs against the different species of schistosomes. Protein kinases are important molecules involved in key cellular processes such as signaling, growth, and differentiation. The kinome of schistosomes has been studied and the suitability of schistosomal protein kinases as targets demonstrated by RNA interference studies. Although protein kinase inhibitors are mostly used in cancer therapy, e.g., for the treatment of chronic myeloid leukemia or melanoma, they are now being increasingly explored for the treatment of non-oncological conditions, including schistosomiasis. Here, we discuss the various approaches including screening of natural and synthetic compounds, de novo drug development, and drug repurposing in the context of the search for protein kinase inhibitors against schistosomiasis. We discuss the status quo of the development of kinase inhibitors against schistosomal serine/threonine kinases such as polo-like kinases (PLKs) and mitogen-activated protein kinases (MAP kinases), as well as protein tyrosine kinases (PTKs).

Regulation of Melanophilin (Mlph) gene expression by the glucocorticoid receptor (GR)

Mlph plays a crucial role in regulating skin pigmentation through the melanosome transport process. Although Mlph is a major component involved in melanosome transport, the mechanism that regulates the expression of the Mlph gene has not been identified. In this study, we demonstrate that Mlph expression is regulated by the glucocorticoid receptor (GR). Alteration of GR activity using a specific GR agonist or antagonist only regulated the expression of Mlph among the 3 key melanosome transport proteins. Translocation of GR from the cytosol into the nucleus following Dex treatment was confirmed by separating the cytosol and nuclear fractions and by immunofluorescence staining. In ChIP assays, Dex induced GR binding to the Mlph promoter and we determined that Dex induced the GR binding motif on the Mlph promoter. Our findings contribute to understanding the regulation of Mlph expression and to the novel role of GR in Mlph gene expression.

Protein Kinases: Potential Drug Targets Against Schistosoma japonicum

Schistosoma japonicum (S. japonicum) infection can induce serious organ damage and cause schistosomiasis japonica which is mainly prevalent in Asia and currently one of the most seriously neglected tropical diseases. Treatment of schistosomiasis largely depends on the drug praziquantel (PZQ). However, PZQ exhibits low killing efficacy on juvenile worms and the potential emergence of its drug resistance is a continual concern. Protein kinases (PKs) are enzymes that catalyze the phosphorylation of proteins and can participate in many signaling pathways in vivo. Recent studies confirmed the essential roles of PKs in the growth and development of S. japonicum, as well as in schistosome-host interactions, and researches have screened drug targets about PKs from S. japonicum (SjPKs), which provide new opportunities of developing new treatments on schistosomiasis. The aim of this review is to present the current progress on SjPKs from classification, different functions and their potential to become drug targets compared with other schistosomes. The efficiency of related protein kinase inhibitors on schistosomes is highlighted. Finally, the current challenges and problems in the study of SjPKs are proposed, which can provide future guidance for developing anti-schistosomiasis drugs and vaccines.

Long non-coding RNA levels can be modulated by 5-azacytidine in Schistosoma mansoni

Schistosoma mansoni is a flatworm that causes schistosomiasis, a neglected tropical disease that affects more than 200 million people worldwide. There is only one drug indicated for treatment, praziquantel, which may lead to parasite resistance emergence. The ribonucleoside analogue 5-azacytidine (5-AzaC) is an epigenetic drug that inhibits S. mansoni oviposition and ovarian development through interference with parasite transcription, translation and stem cell activities. Therefore, studying the downstream pathways affected by 5-AzaC in S. mansoni may contribute to the discovery of new drug targets. Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides with low or no protein coding potential that have been involved in reproduction, stem cell maintenance and drug resistance. We have recently published a catalog of lncRNAs expressed in S. mansoni life-cycle stages, tissues and single cells. However, it remains largely unknown if lncRNAs are responsive to epigenetic drugs in parasites. Here, we show by RNA-Seq re-analyses that hundreds of lncRNAs are differentially expressed after in vitro 5-AzaC treatment of S. mansoni females, including intergenic, antisense and sense lncRNAs. Many of these lncRNAs belong to co-expression network modules related to male metabolism and are also differentially expressed in unpaired compared with paired females and ovaries. Half of these lncRNAs possess histone marks at their genomic loci, indicating regulation by histone modification. Among a selected set of 8 lncRNAs, half of them were validated by RT-qPCR as differentially expressed in females, and some of them also in males. Interestingly, these lncRNAs are also expressed in other life-cycle stages. This study demonstrates that many lncRNAs potentially involved with S. mansoni reproductive biology are modulated by 5-AzaC and sheds light on the relevance of exploring lncRNAs in response to drug treatments in parasites.

Research Progress on Oviposition-Related Genes in Insects

Oviposition-related genes have remained a consistent focus of insect molecular biology. Previous research has gradually clarified our mechanistic understanding of oviposition-related genes, including those related to oviposition-gland-related genes, oogenesis-related genes, oviposition-site-selection-related genes, and genes related to ovulation and hatching. Moreover, some of this research has revealed how the expression of single oviposition-related genes affects the expression of related genes, and more importantly, how individual node genes function to link the expression of upstream and downstream genes. However, the research to date is not sufficient to completely explain the overall interactions among the genes of the insect oviposition system. Through a literature review of a large number of studies, this review provides references for future research on oviposition-related genes in insects and the use of RNAi or CRISPR/Cas9 technology to verify the functions of oviposition-related genes and to prevent and control harmful insects.

Schistosoma mansoni FES Tyrosine Kinase Involvement in the Mammalian Schistosomiasis Outcome and Miracidia Infection Capability in Biomphalaria glabrata

Schistosomiasis is a neglected tropical disease (NTD) caused by helminthes from the Schistosoma genus. This NTD can cause systemic symptoms induced by the deposition of parasite eggs in the host liver, promoting severe complications. Functional studies to increase knowledge about parasite biology are required for the identification of new drug targets, because the treatment is solely based on praziquantel administration, a drug in which the mechanism of action is still unknown. Protein kinases are important for cellular adaptation and maintenance of many organisms homeostasis and, thus, are considered good drug targets for many pathologies. Accordingly, those proteins are also important for Schistosoma mansoni, as the parasite relies on specific environmental signals to develop into its different stages. However, the specific roles of protein kinases in S. mansoni biology are not well understood. This work aims at investigating the tyrosine-protein kinase FES (Feline Sarcoma) functions in the maintenance of S. mansoni life cycle, especially in the establishment of mammalian and invertebrate hosts' infection. In this regard, the verification of Smfes expression among S. mansoni stages showed that Smfes is more expressed in infective free-living stages: miracidia and cercariae. Schistosomula exposed to SmFES-dsRNA in vitro presented a reduction in movement and size and increased mortality. Mice infected with Smfes-knocked-down schistosomula exhibited a striking reduction in the area of liver granuloma and an increased rate of immature eggs in the intestine. Female adult worms recovered from mice presented a reduced size and changes in the ovary and vitellarium; and males exhibited damage in the gynecophoral canal. Subsequently, miracidia hatched from eggs exposed to SmFES-dsRNA presented changes in its capability to infect and to sense the snail mucus. In addition, the SmFES RNAi effect was stable from miracidia to cercariae. The establishment of infection with those cercariae reproduced the same alterations observed for the knocked-down schistosomula infection. Our findings show that SmFES tyrosine kinase (1) is important in schistosomula development and survival; (2) has a role in adult worms pairing and, consequently, female maturation; (3) might be essential for egg antigen expression, thus responsible for inducing granuloma formation and immunomodulation; and (4) is essential for miracidia infection capability. In addition, this is the first time that a gene is kept knocked down during three different S. mansoni life stages and that a tyrosine kinase is implicated in the parasite reproduction and infection establishment in the mammalian host. Accordingly, SmFES should be explored as an alternative to support schistosomiasis treatment and morbidity control.

Slight temperature changes cause rapid transcriptomic responses in Trypanosoma cruzi metacyclic trypomastigotes

Background

Severe changes in temperature can affect the behavior and ecology of some infectious agents. Trypanosoma cruzi is a protozoan that causes Chagas disease. This parasite has high genetic variability and can be divided into six discrete typing units (DTUs). Trypanosoma cruzi also has a complex life-cycle, which includes the process of metacyclogenesis when non-infective epimastigote forms are differentiated into infective metacyclic trypomastigotes (MT). Studies in triatomines have shown that changes in temperature also affect the number and viability of MT.

Methods

The objective of this study was to evaluate how temperature affects the transcriptional profiles of T. cruzi I and II (TcI and TcII) MT by exposing parasites to two temperatures (27 °C and 28 °C) and comparing those to normal culture conditions at 26 °C. Subsequently, RNA-seq was conducted and differentially expressed genes were quantified and associated to metabolic pathways.

Results

A statistically significant difference was observed in the number of MT between the temperatures evaluated and the control, TcII DTU was not strongly affected to exposure to high temperatures compared to TcI. Similar results were found when we analyzed gene expression in this DTU, with the greatest number of differentially expressed genes being observed at 28 °C, which could indicate a dysregulation of different signaling pathways under this temperature. Chromosome analysis indicated that chromosome 1 harbored the highest number of changes for both DTUs for all thermal treatments. Finally, gene ontology (GO) analyses showed a decrease in the coding RNAs involved in the regulation of processes related to the metabolism of lipids and carbohydrates, the evasion of oxidative stress, and proteolysis and phosphorylation processes, and a decrease in RNAs coding to ribosomal proteins in TcI and TcII, along with an increase in the expression of surface metalloprotease GP63 in TcII.

Conclusions

Slight temperature shifts lead to increased cell death of metacyclic trypomastigotes because of the deregulation of gene expression of different processes essential for the TcI and TcII DTUs of T. cruzi.

Deep phosphoproteome analysis of Schistosoma mansoni leads development of a kinomic array that highlights sex-biased differences in adult worm protein phosphorylation

Although helminth parasites cause enormous suffering worldwide we know little of how protein phosphorylation, one of the most important post-translational modifications used for molecular signalling, regulates their homeostasis and function. This is particularly the case for schistosomes. Herein, we report a deep phosphoproteome exploration of adult Schistosoma mansoni, providing one of the richest phosphoprotein resources for any parasite so far, and employ the data to build the first parasite-specific kinomic array. Complementary phosphopeptide enrichment strategies were used to detect 15,844 unique phosphopeptides mapping to 3,176 proteins. The phosphoproteins were predicted to be involved in a wide range of biological processes and phosphoprotein interactome analysis revealed 55 highly interconnected clusters including those enriched with ribosome, proteasome, phagosome, spliceosome, glycolysis, and signalling proteins. 93 distinct phosphorylation motifs were identified, with 67 providing a ‘footprint’ of protein kinase activity; CaMKII, PKA and CK1/2 were highly represented supporting their central importance to schistosome function. Within the kinome, 808 phosphorylation sites were matched to 136 protein kinases, and 68 sites within 37 activation loops were discovered. Analysis of putative protein kinase-phosphoprotein interactions revealed canonical networks but also novel interactions between signalling partners. Kinomic array analysis of male and female adult worm extracts revealed high phosphorylation of transformation:transcription domain associated protein by both sexes, and CDK and AMPK peptides by females. Moreover, eight peptides including protein phosphatase 2C gamma, Akt, Rho2 GTPase, SmTK4, and the insulin receptor were more highly phosphorylated by female extracts, highlighting their possible importance to female worm function. We envision that these findings, tools and methodology will help drive new research into the functional biology of schistosomes and other helminth parasites, and support efforts to develop new therapeutics for their control.

Schistosomes are formidable parasites that cause the debilitating and life-threatening disease human schistosomiasis. We need to better understand the cellular biology of these parasites to develop novel strategies for their control. Within cells, a process called protein phosphorylation controls many aspects of molecular communication or ‘signalling’ and is central to cellular function and homeostasis. Here, using complementary strategies, we have performed the first in-depth characterisation and functional annotation of protein phosphorylation events in schistosomes, providing one of the richest phosphoprotein resources for any parasite to date. Using this knowledge, we have developed a novel tool to simultaneously evaluate signalling processes in these worms and highlight sex-biased differences in adult worm protein phosphorylation. Several proteins were found to be more greatly phosphorylated by female worm extracts, suggesting their possible importance to female worm function. This work will help drive new research into the fundamental biology of schistosomes, as well as related parasites, and will support efforts to develop new drug or vaccine-based therapeutics for their control.

Sm16, A Schistosoma mansoni Immunomodulatory Protein, Fails to Elicit a Protective Immune Response and Does Not Have an Essential Role in Parasite Survival in the Definitive Host

Sm16 is an immunomodulatory protein that seems to play a key role in the suppression of the cutaneous inflammatory response during Schistosoma mansoni penetration of the skin of definitive hosts. Therefore, Sm16 represents a potential target for protective immune responses induced by vaccination. In this work, we generated the recombinant protein rSm16 and produced polyclonal antibodies against this protein to evaluate its expression during different parasite life-cycle stages and its location on the surface of the parasite. In addition, we analyzed the immune responses elicited by immunization with rSm16 using two different vaccine formulations, as well as its ability to induce protection in Balb/c mice. In order to explore the biological function of Sm16 during the course of experimental infection, RNA interference was also employed. Our results demonstrated that Sm16 is expressed in cercaria and schistosomula and is located in the schistosomula surface. Despite humoral and cellular immune responses triggered by vaccination using rSm16 associated with either Freund's or alum adjuvants, immunized mice presented no reduction in either parasite burden or parasite egg laying. Knockdown of Sm16 gene expression in schistosomula resulted in decreased parasite size in vitro but had no effect on parasite survival or egg production in vivo. Thus, our findings demonstrate that although the vaccine formulations used in this study succeeded in activating immune responses, these failed to promote parasite elimination. Finally, we have shown that Sm16 is not vital for parasite survival in the definitive host and hence may not represent a suitable target for vaccine development.

Profiling Transcriptional Regulation and Functional Roles of Schistosoma mansoni c-Jun N-Terminal Kinase

Mitogen-activated protein kinases (MAPKs) play a regulatory role and influence various biological activities, such as cell proliferation, differentiation, and survival. Our group has demonstrated through functional studies that Schistosoma mansoni c-Jun N-terminal kinase (SmJNK) MAPK is involved in the parasite's development, reproduction, and survival. SmJNK can, therefore, be considered a potential target for the development of new drugs. Considering the importance of SmJNK in S. mansoni maturation, we aimed at understanding of SmJNK regulated signaling pathways in the parasite, correlating expression data with S. mansoni development. To better understand the role of SmJNK in S. mansoni intravertebrate host life stages, RNA interference knockdown was performed in adult worms and in schistosomula larval stage. SmJNK knocked-down in adult worms showed a decrease in oviposition and no significant alteration in their movement. RNASeq libraries of SmJNK knockdown schistosomula were sequenced. A total of 495 differentially expressed genes were observed in the SmJNK knockdown parasites, of which 373 were down-regulated and 122 up-regulated. Among the down-regulated genes, we found transcripts related to protein folding, purine nucleotide metabolism, the structural composition of ribosomes and cytoskeleton. Genes coding for proteins that bind to nucleic acids and proteins involved in the phagosome and spliceosome pathways were enriched. Additionally, we found that SmJNK and Smp38 MAPK signaling pathways converge regulating the expression of a large set of genes. C. elegans orthologous genes were enriched for genes related to sterility and oocyte maturation, corroborating the observed phenotype alteration. This work allowed an in-depth analysis of the SmJNK signaling pathway, elucidating gene targets of regulation and functional roles of this critical kinase for parasite maturation.