TmToll-7 Plays a Crucial Role in Innate Immune Responses Against Gram-Negative Bacteria by Regulating 5 AMP Genes in Tenebrio molitor.

Although it is known that the Drosophila Toll-7 receptor plays a critical role in antiviral autophagy, its function in other insects has not yet been reported. Here, we have identified a Toll-like receptor 7 gene, TmToll-7, in the coleopteran insect T. molitor and examined its potential role in antibacterial and antifungal immunity. We showed that TmToll-7 expression was significantly induced in larvae 6 h after infection with Escherichia coli and Staphylococcus aureus and 9 h after infection with Candida albicans. However, even though TmToll-7 was induced by all three pathogens, we found that TmToll-7 knockdown significantly reduced larval survival to E. coli, but not to S. aureus, and C. albicans infections. To understand the reasons for this difference, we examined the effects of TmToll-7 knockdown on antimicrobial peptide (AMP) gene expression and found a significant reduction of E. coli-induced expression of AMP genes such as TmTenecin-1, TmDefensin-1, TmDefensin-2, TmColeoptericin-1, and TmAttacin-2. Furthermore, TmToll-7 knockdown larvae infected with E. coli showed significantly higher bacterial growth in the hemolymph compared to control larvae treated with Vermilion dsRNA. Taken together, our results suggest that TmToll-7 plays an important role in regulating the immune response of T. molitor to E. coli.

Molecular Cloning and Effects of Tm14-3-3ζ-Silencing on Larval Survivability Against E. coli and C. albicans in Tenebrio molitor.

The 14-3-3 family of proteins performs key regulatory functions in phosphorylation-dependent signaling pathways including cell survival and proliferation, apoptosis, regulation of chromatin structure and autophagy. In this study, the zeta isoform of 14-3-3 proteins (designated as Tm14-3-3ζ) was identified from the expressed sequence tags (ESTs) and RNA sequencing (RNA-Seq) database of the coleopteran pest, Tenebrio molitor. Tm14-3-3ζ messenger RNA (mRNA) is expressed at higher levels in the immune organs of the larval and adult stages of the insect and exhibit almost five-fold induction within 3 h post-infection of the larvae with Escherichia coli and Candida albicans. To investigate the biological function of Tm14-3-3ζ, a peptide-based Tm14-3-3ζ polyclonal antibody was generated in rabbit and the specificity was confirmed using Western blot analysis. Immunostaining and confocal microscopic analyses indicate that Tm14-3-3ζ is mainly expressed in the membranes of midgut epithelial cells, the nuclei of fat body and the cytosol of hemocytes. Gene silencing of Tm14-3-3ζ increases mortality of the larvae at 7 days post-infection with E. coli and C. albicans. Our findings demonstrate that 14-3-3ζ in T. molitor is essential in the host defense mechanisms against bacteria and fungi.

Inhibition of glutaminase selectively suppresses the growth of primary acute myeloid leukemia cells with IDH mutations.

The incidence of mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) in de novo acute myeloid leukemia (AML) is approximately 20%. These mutations result in distinct metabolic characteristics including dependency of cancer cells on glutamine as the main source for α-ketoglutarate, which is consumed by leukemia cells to produce a cancer-derived metabolite, 2-hydroxyglutarate. We sought to exploit this glutamine addiction therapeutically in mutant IDH primary AML cells from patients by measuring cell growth after exposure to a small molecule glutaminase inhibitor, BPTES. We found that BPTES only suppressed the growth of AML cells expressing mutant IDH compared with those expressing wild type IDH. This study lays the groundwork for strategies to target a specific subtype of AML metabolically with IDH mutations with a unique reprogramming of intermediary metabolism that culminates in glutamine dependency of cancer cells for survival.