Search bioRxiv⌕ Search

bioRxiv · 10.1101/2022.10.04.510778

Effects of protoscoleces excretory-secretory products of Echinococcus granulosus on hepatocyte growth, function, and glucose metabolism

Abstract

Cystic echinococcosis (CE) is one of the most widespread and harmful zoonotic parasitic diseases and it most commonly affects the liver. In this study, we characterized multiple changes in mouse hepatocytes following treatment with excretory-secretory (ES) products of Echinococcus granulosus protoscoleces by a factorial experiment. The cell counting kit-8 assay (CCK-8), the 5-ethynyl-2-deoxyuridine (EdU) assay, and flow cytometry were used to detect the growth of hepatocytes. Inverted microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to observe the morphology and ultrastructure of hepatocytes. An automatic biochemical analyzer and an ELISA detection kit were used to determine six conventional hepatocyte enzymatic indices, the levels of five hepatocyte-synthesized substances, and the contents of glucose and lactate. Western blot analysis was conducted to analyze the protein expression of six rate-limiting enzymes in the glucose metabolism pathway in hepatocytes: glutamic-pyruvic transaminase (ALT), glutamic-oxalacetic transaminase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), gamma-glutamyl transpeptidase (GGT), and leucine arylamidase (LAP). The results of the CCK-8 and EdU assays both showed that ES could inhibit the proliferation of hepatocytes, and flow cytometry indicated that ES could promote apoptosis of hepatocytes. After ES treatment, the ultrastructure of hepatocytes was disrupted to a certain extent. The changes in the cell membrane and microvilli were observed through SEM, and the changes in the nucleus, mitochondria, and rough endoplasmic reticulum were observed through TEM. After ES treatment, the enzymatic activities of the six hepatocyte enzymes were increased in addition to the Fe metabolism and the synthesis of albumin (ALB), uric acid (UA), and urea, whereas the synthesis of transferrin (TRF) was decreased. The expression levels of all six key enzymes in the glucose metabolism pathway in hepatocytes were decreased, and the biological effects were significantly inhibited. We analyzed the causes and possible complications caused by various changes and advocate corresponding measures. We also propose possible mechanisms by which protoscoleces cause hepatocyte necrosis, but the specific mechanism requires further study. Author SummaryEchinococcus granulosus, the most widely distributed and most infected tapeworm, has caused serious economic and social burdens to pastoral areas in China. The metacestodes of Echinococcus granulosus mainly infect the liver of intermediate hosts (humans, cattle, sheep, etc.). Currently, the effects of Echinococcus granulosus on hepatocytes ultrastructure, enzymology, function, and glucose metabolism have not been characterized, and accurate characterization is crucial in the study of related pathogenesis and preventive therapy. Here, we characterize multiple changes in hepatocytes using excretory-secretory (ES) products of Echinococcus granulosus protoscoleces and mouse hepatocyte action by a factorial experiment. We found that ES inhibited hepatocyte proliferation and promoted hepatocyte apoptosis. ES can cause a certain degree of damage to the cell membrane, nucleus, mitochondria, and endoplasmic reticulum of hepatocytes. After ES treatment, six enzymatic indexes of hepatocytes were elevated, they were ALT, AST, LDH, ALP, GGT, and LAP, and Fe, ALB, UA, and urea levels synthesized by hepatocytes were significantly higher and TRF levels were significantly lower. Reduced expression of rate-limiting enzymes in six pathways of glucose metabolism in hepatocytes, including PFK-1, IDH, G-6-PD, GS, GP, and GLUT-2, indicating that ES inhibits glucose metabolism in hepatocytes. Our study not only characterized the effects of ES on hepatocytes in detail but also proposed the possible mechanisms causing these effects, which provided a basis for subsequent studies on related pathogenesis and prevention, and treatment.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Luo, G., Li, H., Lu, Q., Cao, J., Lv, H., Jiang, Y.. 2022-10-04. Effects of protoscoleces excretory-secretory products of Echinococcus granulosus on hepatocyte growth, function, and glucose metabolism. https://doi.org/10.1101/2022.10.04.510778

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Functional characterization of Rho GTPase activating proteins SYDE1 and SYDE2

The human genome encodes more than 60 proteins containing Rho GTPase activating protein (RhoGAP) domains, many of which remain understudied with respect to their target specificity and biological roles. SYDE1 and SYDE2 are two such orphan RhoGAPs, for which there are few studies characterizing their biochemical and cellular functions and conflicting reports identifying their cognate GTPases. We previously identified SYDE1 and SYDE2 in a screen for substrates of the c-Jun N-terminal kinases. Here, we show that SYDE1 and SYDE2 are preferentially phosphorylated by JNK1 relative to other mitogen-activated protein kinases (MAPKs) at sites proximal to a kinase docking region. Purified SYDE1 and SYDE2 are shown to have significant catalytic GAP activity toward RhoA, Rac1, and Cdc42. However, neither up- nor down-regulation of SYDE1/2 expression leads to detectable changes in bulk GTP loading of any of these GTPases. Nevertheless, we demonstrate that SYDE1 and SYDE2, in a partially GAP-dependent manner, increase cell spreading and number of focal adhesions, and promote more directionally persistent migration in HEK293 cells. Together, these findings establish SYDE1 and SYDE2 as robust JNK substrates with catalytic activity toward a set of Rho GTPases and reveal basic functions of SYDE1 and SYDE2 in regulating cell morphology, adhesion, and migration.

cell biology↗

The filopodial scaffold polyphosphate dictates cell adhesion-versus-invasion decisions

Inorganic polyphosphate (polyP) is an ancient polymer conserved across all life, serving cell type and location specific functions in every major compartment. Yet its role at the plasma membrane, where it accumulates to peak levels in many primary cells, is largely unknown. Here we identify polyP as a stabilizing component of filopodia, actin based membrane protrusions that govern cell adhesion, contact inhibition, and chemotaxis. Elevating cellular polyP increases filopodial stability and enhances cell adhesion, whereas reducing polyP accelerates filopodial disassembly and promotes cell migration. Mechanistically, we find that polyP acts as a structural filopodial scaffold, recruiting and organizing IRSp53, a membrane curvature inducing protein. We show that metastatic fibroblasts and breast cancer organoids carry markedly reduced and intracellularly reorganized polyP levels relative to their non transformed counterparts. Restoring endogenous polyP via lipid nanoparticle delivery suppresses their invasive phenotypes and reverses prometastatic gene expression signatures, implicating polyP as a primordial tumor suppressor.

cell biology↗

Mitochondrial transfer mediates metabolic communication between beta cells and islet macrophages

Pancreatic islet macrophages support islet homeostasis and adapt their metabolic program in response to environmental cues, including beta cell released factors. Intercellular mitochondrial transfer is a biological process that modulates cellular responses. To test whether beta cells, which are strongly secretory, transfer mitochondria to islet macrophages, we generated mice with beta cell-specific expression of mitochondrial GFP (PhAMfloxIns1Cre). We demonstrate that beta cells transfer mitochondria to islet macrophages in vivo and in vitro. Diabetogenic stressors did not alter the frequency of mitochondrial transfer and macrophages containing beta cell-derived GFP exhibit increased protein synthesis rates. RNA-seq identified upregulation of activity-regulated cytoskeleton associated protein (Arc) in macrophages receiving beta cell-derived mitochondria, while disruption of actin cytoskeleton dynamics prevented mitochondrial transfer. Together, these findings identify mitochondrial transfer as a previously unrecognized mechanism of beta cell-macrophage communication that may contribute to islet homeostasis and immune regulation.

cell biology↗