bioRxiv Science⌕ 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

Differential requirement for the Ire1 luminal domain in Candida albicans drug susceptibility and pathogenicity

The opportunistic human pathogen Candida albicans depends on the unfolded protein response (UPR) for cell wall integrity, antifungal tolerance, filamentous growth, and virulence. The UPR is driven by the conserved transmembrane sensor Ire1, which is activated either by misfolded proteins through its luminal domain or by lipid bilayer stress (LBS) through its transmembrane domain. In budding yeast, these two activation modes deploy divergent transcriptional programs. Whether the requirement for these two input domains is separable in C. albicans, where the cell membrane and cell wall are themselves the targets of major antifungal drug classes, remains unknown. Here, we engineered a C. albicans strain expressing Ire1 lacking an intact luminal domain (ire1{Delta}LD), which no longer detects proteotoxic stress. The ire1{Delta}LD strain grew in the presence of the azole antifungals fluconazole and miconazole but was highly sensitive to heat shock, cell wall stress, and the echinocandin caspofungin. It was also unable to sustain filamentous growth and showed reduced virulence in a Caenorhabditis elegans infection model. RNA sequencing revealed only modest changes to the steady-state transcriptome of ire1{Delta}LD cells. Together, these findings define a differential requirement for the input domains of C. albicans Ire1, uncoupling growth under azole-induced membrane stress from the cell wall, thermal, and virulence-associated outputs that depend on proteotoxic sensing, a distinction that could inform antifungal strategies targeting the UPR.

cell biology↗

Nucleosome Core Allostery Governs Chromatin Recognition and Cell Fate

Nucleosomes regulate chromatin folding, accessibility, and factor recruitment. Current models primarily attribute these functions to histone tail modifications, while the core is largely viewed as a structural scaffold. Yet subtle changes within the nucleosome core can produce profound functional consequences, and the mechanisms underlying these effects remain unclear. Here, we describe nucleosome core allostery as a fundamental principle of chromatin regulation that amplifies the impact of minimal nucleosome variations. Leveraging natural differences between H2A.Z variants, we show that the nucleosome core encodes distinct conformational dynamics that propagate allosterically, thereby controlling nucleosome accessibility and recognition by chromatin factors. As a result, a single buried amino acid substitution alone is sufficient to reprogram nucleosome dynamics and bias cell identity. Our findings establish the nucleosome core as an allosteric regulatory module and provide a generalizable framework for how subtle variation within nucleosomes is amplified into diverse biological outcomes in development and disease.

cell biology↗

YAP/TAZ-controlled ERK dynamics coordinate progenitor expansion and differentiation commitment

Progenitor cells must proliferate to expand the cell population, yet terminal differentiation requires this proliferative state to end. How signaling controls the duration of this proliferative window remains poorly understood. Using adipogenesis and live single-cell imaging of differentiation, cell-cycle, and ERK-activity reporters, we show that YAP and TAZ coordinate progenitor expansion with differentiation commitment by regulating ERK dynamics. YAP/TAZ maintain cells in a fluctuating high-ERK state that promotes proliferation while actively keeping the differentiation driver PPARG below the threshold for irreversible commitment. Crucially, this differentiation block is not explained by proliferation alone: inhibiting CDK4/6 or AKT suppressed proliferation without restoring differentiation, whereas MEK-ERK inhibition restored differentiation even when YAP/TAZ activity remained high. As YAP/TAZ activity decreases, dampened ERK fluctuations trigger PPARG activation. These findings support a self-limiting model in which YAP/TAZ-driven progenitor expansion progressively increases cell density and contact-dependent Hippo signaling, reducing YAP/TAZ activity and terminating the proliferative phase. Consequently, transient YAP/TAZ activation expands the progenitor pool while preserving subsequent differentiation, whereas sustained activation suppresses commitment. Together, these findings identify YAP/TAZ-controlled ERK dynamics as the nexus coordinating progenitor expansion with terminal differentiation and suggest that slower density-dependent Hippo feedback may set the duration of this proliferative window to regulate differentiated cell-number output.

cell biology↗