Antibody-Decorated Nanoplatform to Reprogram Macrophage and Block Immune Checkpoint LSECtin for Effective Cancer Immunotherapy.

Repolarizing tumor-associated macrophages (TAMs) into tumor-inhibiting M1 macrophages has been considered a promising strategy for enhanced cancer immunotherapy. However, several immunosuppressive ligands (e.g., LSECtin) can still be highly expressed on M1 macrophages, inducing unsatisfactory therapeutic outcomes. We herein developed an antibody-decorated nanoplatform composed of PEGylated iron oxide nanoparticles (IONPs) and LSECtin antibody conjugated onto the surface of IONPs via the hydrazone bond for enhanced cancer immunotherapy. After intravenous administration, the tumor microenvironment (TME) pH could trigger the hydrazone bond breakage and induce the disassociation of the nanoplatform into free LSECtin antibodies and IONPs. Consequently, the IONPs could repolarize TAMs into M1 macrophages to remodel immunosuppressive TME and provide an additional anticancer effect via secreting tumoricidal factors (e.g., interlukin-12). Meanwhile, the LSECtin antibody could further block the activity of LSECtin expressed on M1 macrophages and relieve its immunosuppressive effect on CD8+ T cells, ultimately leading to significant inhibition of tumor growth.

Evaluation of candidate reference genes for gene expression analysis in the brassica leaf beetle, Phaedon brassicae (Coleoptera: Chrysomelidae).

The brassica leaf beetle Phaedon brassicae is a notorious defoliator of cruciferous vegetables. However, few molecular studies of this pest have been conducted due to limited sequence data. Recently, RNA sequencing has offered a powerful platform to generate numerous transcriptomic data, which require RT-qPCR to validate target gene expression. The selection of reliable reference genes to normalize RT-qPCR data is a prerequisite for gene expression analysis. In the present study, the expression stabilities of eight candidate reference genes under biotic conditions (development stages and various tissues) and abiotic perturbations (thermal stress and pesticide exposure) were evaluated using four different statistical algorithms. The optimal suites of reference genes were recommended for the respective experimental conditions. For tissue expression analysis, RPL32 and EF-1α were recommended as the suitable reference genes. RPL19 and TBP were the optimal reference genes across different developmental stages. RPL32 and TBP were identified as the most suitable references for thermal stress. Furthermore, RPL32 and RPL19 were ranked as the best references for insecticide exposure. This work provides a systematic exploration of the optimal reference genes for the respective experimental conditions, and our findings would facilitate molecular studies of P. brassicae.

Dissecting the roles of FTZ-F1 in larval molting and pupation, and the sublethal effects of methoxyfenozide on Helicoverpa armigera.

BACKGROUND: In holometabolous insects, the major developmental transitions - larval molting and pupation - are triggered by a pulse of 20-hydroxyecdysone (20E) and coordinated by juvenile hormone. Methoxyfenozide (MF), an ecdysteroid agonist, represents a new class of insect growth regulators and is effective against lepidopteran pests. Fushi-tarazu factor 1 (FTZ-F1) is an ecdysone-inducible transcription factor. To date, the effect of MF on 20E-response genes remains unclear, and we speculate the involvement of FTZ-F1 in MF's growth regulating effect. RESULTS: MF at LC25 and LC10 caused severe ecdysis failure in Helicoverpa armigera, extended their larval duration, lowered their pupal weight, and reduced the respiratory, pupation and emergence rates. Furthermore, sublethal doses of MF inhibited ecdysteroidogenesis and lowered the intrinsic 20E titer, but showed an inductive effect on 20E-response genes including HaFTZ-F1. HaFTZ-F1, predominantly expressed in larval epidermis, was markedly upregulated before or right after larval ecdysis, and maintained a high level in prepupal stage. Knockdown of HaFTZ-F1 in 4th-instar larvae severely impaired larval ecdysis, whereas its knockdown in final-instar larvae caused abnormal pupation. Moreover, knocking down HaFTZ-F1 downregulated three critical ecdysteroidogenesis genes, lowered 20E titer, and suppressed the expression of 20E receptors and 20E-response genes. The introduction of 20E into HaFTZ-F1-RNAi larvae partly relieved the negative effects on the 20E-induced signaling cascade. CONCLUSION: Our findings reveal the adverse effects of sublethal doses of MF on the development of H. armigera and elucidate the resulting perturbations on the 20E-induced signaling cascade; we propose that HaFTZ-F1 regulates ecdysis and pupation by mediating 20E titer and its signaling pathway. © 2020 Society of Chemical Industry.

Effects of starvation on respiratory metabolism and energy metabolism in the cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae).

Intermittent food shortages are commonly encountered in the wild. To cope with the threat of starvation, insects initiate a suite of behavioral activities and physiological countermeasures. The cotton bollworm, Helicoverpa armigera, is a major agricultural pest worldwide, but how H. armigera modulates its metabolism under starvation remains ambiguous. In the present study, the respiratory rates (V̇O2; ml g-1 h-1) from the third-larval instar to the pupal stage were first determined. Our results highlighted a transient rise during the larval-larval molt and larval-pupal transition, followed by a sharp decline in the pupal stage and, finally, an upward trend before eclosion. When subjected to food deprivation, the starved larvae experienced a significant decline in the rates of O2 consumed and CO2 produced, as well as in respiratory quotient (RQ) values, indicative of severe metabolic depression during starvation and a shift of metabolic substrates with prolonged starvation. For metabolic substrate analysis, an apparent decline in triglyceride and glycogen contents was observed in the starved larvae, and the hemolymph trehalose content was significantly reduced throughout starvation. In addition, comparative transcriptome analysis showed that 48 h of larval starvation caused substantial transcriptional regulations in several energetically costly processes, wherein the marked up-regulations were detected in the pathways of glycolysis and fatty acid metabolism. Overall, our work makes a comprehensive study on the respiratory rate and energy metabolism in the starved H. armigera larvae, and provides a deep insight into the physiological adaptive strategies to alleviate nutritional stress.