Weingartner, M. | Search bioRxiv

bioRxiv2026

The eIF4E-homologous protein 4EHP (nCBP) regulates thermotolerance by modulating heat-responsive mRNAs and the HSP repertoire in Arabidopsis thaliana

Translation initiation factors of the eIF4E family play a crucial role in regulating translation and the cellular metabolism of mRNAs. Research has addressed the role of canonical 4E family isoforms in development, stress response, and during viral infection. Nevertheless, the class-II eIF4E family member cap-binding protein 4EHP (nCBP), has remained poorly characterized in plant stress responses. In this study, we show that loss of 4EHP confers enhanced basal and acquired thermotolerance and causes a mild flowering delay without major root defects. Under heat stress, 4EHP-GFP re-localizes from a diffuse cytosolic pattern to cytoplasmatic foci, co-localizing with canonical stress granule (SG) markers. Transcriptomic analysis under control, acclimation and heat stress conditions reveals that 4EHP limits the accumulation of heat-responsive mRNAs, especially those encoding heat shock proteins (HSPs), which remain constitutively expressed in 4ehp-1 mutant under control and heat stress conditions. Proteomic analysis also indicates that the absence of 4EHP alters the repertoire of HSPs compared with wild type (Col-0), especially upon heat stress, without significantly impairing the recruitment of corresponding mRNAs to translationally active polysomes. Together, our results indicate that 4EHP negatively modulates the accumulation of a specific subset of heat-responsive mRNAs fine-tuning chaperone production, via heat-responsive SG regulatory pathways.

plant biology↗

bioRxiv2021

Albendazole reduces endoplasmic reticulum stress induced by Echinococcus multilocularis in mice

BackgroundEchinococcus multilocularis causes alveolar echinococcosis (AE), a rising zoonotic disease in the northern hemisphere. Treatment of this fatal disease is limited to chemotherapy using benzimidazoles and surgical intervention, with relatively frequent disease recurrence in cases without radical surgery. Elucidating the molecular mechanisms underlying E. multilocularis infections and host-parasite interactions aids developing novel therapeutic options. This study explored an involvement of unfolded protein response (UPR) and endoplasmic reticulum-stress (ERS) during E. multilocularis infection in mice. MethodsE. multilocularis- and mock-infected C57BL/6 mice were subdivided six weeks after infection into vehicle and albendazole (ABZ) treated groups. Eight weeks later, liver tissue was collected to examine mRNA, microRNA (miR) and protein expression of UPR- and ERS-related genes. ResultsE. multilocularis infection upregulated UPR- and ERS-related proteins, including ATF6, CHOP, GRP78, ERP72, H6PD and calreticulin, whilst PERK and its target eIF2 were not affected, and IRE1 and ATF4 were downregulated. ABZ treatment in E. multilocularis infected mice reversed the increased ATF6 and calreticulin protein expression, tended to reverse increased CHOP, GRP78, ERP72 and H6PD expression, and decreased ATF4 and IRE1 expression to levels seen in mock-infected mice. The expression of miR-146a-5p (downregulated by IRE1) and miR-1839-5p (exhibiting a unique target site in the IRE1 3UTR) were significantly increased in E. multilocularis infected mice, an effect reversed by ABZ treatment. Other miRs analyzed were not altered in E. multilocularis infected mice. Conclusions and SignificanceAE causes UPR activation and ERS in mice. The E. multilocularis-induced ERS was ameliorated by ABZ treatment, indicating its effectiveness to inhibit parasite proliferation and downregulate its activity status. ABZ itself did not affect UPR in control mice. Identified miR-146a-5p and miR-1839-5p might represent biomarkers of E. multilocularis infection. Modulation of UPR and ERS, in addition to ABZ administration, could be exploited to treat E. multilocularis infection. Author summaryAlveolar echinococcosis is a zoonotic disease caused by the fox tapeworm Echinococcus multilocularis. Treatment of this fatal disease is limited to surgical intervention, preferably radical curative surgery if possible, and the use of parasitostatic benzimidazoles. It is not yet fully understood how the parasite can remain in the hosts tissue for prolonged periods, complicating the development of therapeutic applications. This work investigated an involvement of the unfolded protein response (UPR) and endoplasmic reticulum-stress (ERS) during E. multilocularis infection and upon treatment with albendazole (ABZ) in mice. The results revealed increased expression levels of the ERS sensor ATF6 and of downstream target genes in liver tissue of E. multilocularis- compared to mock-infected mice. Additionally, H6PD, generating NADPH within the endoplasmic reticulum, and the lectin-chaperone calreticulin were increased in E. multilocularis infected liver tissue while the expression of the ERS associated genes ATF4 and IRE1 were decreased. The miR-1839-5p and miR-146-p, linked to IRE1, were elevated upon E. multilocularis infection, offering potential as novel biomarkers of alveolar echinococcosis. The observed gene expression changes were at least partially reversed by ABZ treatment. Whether modulation of UPR and ERS targets can improve the therapy of alveolar echinococcosis remains to be investigated.

pathology↗