Hypothetical granulin-like molecule from Fasciola hepatica identified by bioinformatics analysis

Animal granulins: In the GRN scheme of things

Granulins are conserved in nearly all metazoans, with an intriguing loss in insects. These pleiotropic peptides are involved in numerous physiological and pathological processes yet have been overwhelmingly examined in mammalian systems. While work in other animal models has been informative, a richer understanding of the proteins should be obtained by integrating knowledge from all available contexts. The main bodies of work described here include 1) the structure-function relationships of progranulin and its cleavage products, 2) the role of expanded granulin gene families and different isoforms in fish immunology, 3) the release of granulin peptides to promote host angiogenesis by parasitic worms, 4) a diversity of molluscan uses for granulins, including immune activation in intermediate hosts to trematodes, 5) knowledge gained on lysosomal functions from C. elegans and the stress-related activities of granulins. We provide an overview of functional reports across the Metazoa to inform much-needed future research.

An Update on the Pathogenesis of Fascioliasis: What Do We Know?

Fasciola hepatica is a trematode parasite distributed worldwide. It is known to cause disease in mammals, producing significant economic loses to livestock industry and burden to human health. After ingestion, the parasites migrate through the liver and mature in the bile ducts. A better understanding of the parasite's immunopathogenesis would help to develop efficacious therapeutics and vaccines. Currently, much of our knowledge comes from in vitro and in vivo studies in animal models. Relatively little is known about the host-parasite interactions in humans. Here, we provide a narrative review of what is currently know about the pathogenesis and host immune responses to F. hepatica summarizing the evidence available from the multiple hosts that this parasite infects.

Granulin Expression in Hamsters during Opisthorchis viverrini Infection-Induced Cholangiocarcinogenesis

The secreted growth factor granulin (GRN) is upregulated during diverse epithelial cancers. GRN stimulates cell growth and development while inhibiting apoptosis. Orthologues of vertebrate granulins evolved in other animals including the liver fluke Opisthorchis viverrini. Curiously, liver fluke granulin, termed Ov-GRN-1 promotes cholangiocarcinogenesis during chronic opisthorchiasis but, by contrast, limited information is available concerning mammalian GRN during liver fluke infection-induced cholangiocarcinoma (CCA). Here we investigated the expression of mammalian granulin in the O. viverrini-associated a hamster model of opisthorchiasis and liver fluke infection-induced CCA. Male Syrian golden hamsters were assigned to one of four treatment groups, each group included 30 hamsters: 1) normal (control), 2) infected with O. viverrini (OV); 3) exposed to N-dimethylnitrosamine in drinking water (DMN); and 4) infected with O. viverrini and exposed to DMN (OVDMN). Immunohistochemistry using an anti-granulin specific probe for mammalian granulin was undertaken to monitor expression and location in hepatobiliary tissues of the hamsters. In parallel, cognate studies of transcription of mRNA and protein. Histopathological examination revealed development of proliferative lesions from the onset and eruption of CCA onwards, an outcome that was most prominent in the OVDMN hamsters. Proliferating cell nuclear antigen (PCNA) index rose continuously from initiation of infection and increased with lesion progression in OV, DMN and markedly in OVDMN hamsters. Expression of GRN in biliary was elevated in biliary epithelial cells in CCA lesions in hamsters in the DMN and OVDMN groups. Expression of GRN as assayed by western blot and RT-PCR reflected the same trend as seen with PCNA. Together the histopathogical and molecular assay based findings revealed marked expression of granulin during cholangiocarcinoma in these hamsters, and highlighted the prospect that granulin represents a potential prognostic marker for cholangiocarcinoma.

Structure dissection of zebrafish progranulins identifies a well-folded granulin/epithelin module protein with pro-cell survival activities

The ancient and pluripotent progranulins contain multiple repeats of a cysteine-rich sequence motif of ∼60 amino acids, called the granulin/epithelin module (GEM) with a prototypic structure of four β-hairpins zipped together by six inter-hairpin disulfide bonds. Prevalence of this disulfide-enforced structure is assessed here by an expression screening of 19 unique GEM sequences of the four progranulins in the zebrafish genome, progranulins 1, 2, A and B. While a majority of the expressed GEM peptides did not exhibit uniquely folded conformations, module AaE from progranulin A and AbB from progranulin B were found to fold into the protopypic 4-hairpin structure along with disulfide formation. Module AaE has the most-rigid three-dimensional structure with all four β-hairpins defined using high-resolution (H-¹⁵ N) NMR spectroscopy, including 492 inter-proton nuclear Overhauser effects, 23 ³ J(HN,H_α ) coupling constants, 22 hydrogen bonds as well as 45 residual dipolar coupling constants. Three-dimensional structure of AaE and the partially folded AbB re-iterate the conformational stability of the N-terminal stack of two beta-hairpins and varying degrees of structural flexibility for the C-terminal half of the 4-hairpin global fold of the GEM repeat. A cell-based assay demonstrated a functional activity for the zebrafish granulin AaE in promoting the survival of neuronal cells, similarly to what has been found for the corresponding granulin E module in human progranulin. Finally, this work highlights the remaining challenges in structure-activity studies of proteins containing the GEM repeats, due to the apparent prevalence of structural disorder in GEM motifs despite potentially a high density of intramolecular disulfide bonds.

Clonorchis sinensis granulin: identification, immunolocalization, and function in promoting the metastasis of cholangiocarcinoma and hepatocellular carcinoma

Background

Long-term infections by Clonorchis sinensis are associated with cholangitis, cholecystitis, liver fibrosis, cirrhosis, and even liver cancer. Molecules from the worm play vital roles in disease progress. In the present study, we identified and explored molecular characterization of C. sinensis granulin (CsGRN), a growth factor-like protein from C. sinensis excretory/secretory products (CsESPs).

Methods

The encoding sequence and conserved domains of CsGRN were identified and analysed by bioinformatics tools. Recombinant CsGRN (rCsGRN) protein was expressed in Escherichia coli BL21 (DE3). The localisation of CsGRN in adult worms and Balb/c mice infected with C. sinensis was investigated by immunofluorescence and immunohistochemistry, respectively. Stable CsGRN-overexpressed cell lines of hepatoma cells (PLC-GRN cells) and cholangiocarcinoma cells (RBE-GRN cells) were constructed by transfection of eukaryotic expression plasmid of pEGFP-C1-CsGRN. The effects on cell migration and invasion of CsGRN were assessed through the wound-healing assay and transwell assay. The levels of matrix metalloproteinase 2 and 9 (MMP2 and MMP9) in PLC-GRN or RBE-GRN cells were detected by real-time PCR (qRT-PCR). The levels of E-cadherin, vimentin, N-cadherin, zona occludens proteins (ZO-1), β-catenin, phosphorylated ERK (p-ERK) and phosphorylated AKT (p-AKT) were analysed by Western blotting.

Results

CsGRN, including the conserved GRN domains, was confirmed to be a member of the granulin family. CsGRN was identified as an ingredient of CsESPs. CsGRN was localised in the tegument and testes of the adult worm. Furthermore, it appeared in the cytoplasm of hepatocytes and biliary epithelium cells from infected Balb/c mouse. The enhancement of cell migration and invasion of PLC-GRN and RBE-GRN cells were observed. In addition, CsGRN upregulated the levels of vimentin, N-cadherin, β-catenin, MMP2 and MMP9, while it downregulated the level of ZO-1 in PLC-GRN/RBE-GRN cells. In total proteins of liver tissue from rCsGRN immunised Balb/c mice, vimentin level decreased, while E-cadherin level increased when compared with the control groups. Meanwhile, the levels of p-ERK reached a peak at 4 weeks post immunisation and the level of p-AKT did at 2 weeks after immunisation.

Conclusions

The encoding sequence and molecular characteristics of CsGRN were identified. As a member of granulin superfamily, CsGRN induced mesenchymal characteristics of PLC and RBE cells and was found to regulate the activities of the downstream molecules of the ERK and PI3K/AKT signalling pathways, which could contribute to the enhancement of cell migration and invasion.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-017-2179-4) contains supplementary material, which is available to authorized users.