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Reactive oxygen species (ROS) are considered a major cause of ageing and ageing‐related diseases through protein carbonylation. Little is known about the molecular mechanisms that confer protection against ROS. Here, we observed that, compared with nondiapause‐destined pupae, high protein carbonyl levels are present in the brains of diapause‐destined pupae, which is a 'non‐ageing' phase in the moth Helicoverpa armigera. Protein carbonyl levels respond to ROS and decrease metabolic activity to induce diapause in order to extend lifespan. However, protein carbonylation in the brains of diapause‐destined pupae still occurs at a physiological level compared to young adult brains. We find that ROS activate Akt, and Akt then phosphorylates the transcription factor CREB to facilitate its nuclear import. CREB binds to the promoter of carbonyl reductase 1 (CBR1) and regulates its expression. High CBR1 levels reduce protein carbonyl levels to maintain physiological levels. This is the first report showing that the moth brain can naturally control protein carbonyl levels through a distinct ROS‐Akt‐CREB‐CBR1 pathway to extend lifespan. [ABSTRACT FROM AUTHOR]

Previous studies have shown that high physiological levels of reactive oxygen species (ROS) in the brain promote pupal diapause, which extends the pupal lifespan. However, the molecular mechanisms of ROS generation are unclear. In this paper, we found that mitochondrial ROS (mtROS) levels in the brains of Helicoverpa armigera diapause‐destined pupae (DP) were higher and that the expression of cytochrome oxidase subunit IV (COXIV) was lower than in NP. In addition, downregulating COXIV caused mitochondrial dysfunction which elevated mtROS levels. Protein kinase A (PKA) was downregulated in DP, which led to the downregulated expression of the mitochondrial transcription factor TFAM. Low TFAM activity failed to promote COXIV expression and resulted in the high ROS levels that induced diapause. In addition, low sirtuin 2 expression suppressed glucose‐6‐phosphate dehydrogenase (G6PD) deacetylation at K382, which led to reduced G6PD activity and low NADPH levels, thereby maintaining high levels of ROS. Two proteins, COXIV and G6PD, thus play key roles in the elevated accumulation of ROS that induce diapause and extend the pupal lifespan. [ABSTRACT FROM AUTHOR]

BACKGROUND: Diapause is the arrest of the development of insects and can be used for the development of effective agricultural pest management strategies. Heat shock protein 70 (Hsp70) is reported to be up‐regulated during diapause to maintain survival in some insect species. However, its regulatory mechanism is unknown. RESULTS: Expression of hsp70 in Helicoverpa armigera was found to be up‐regulated in diapause pupal brains. To elucidate the molecular regulatory mechanisms of hsp70, we focused our attention on its transcription factor, heat shock factor 1 (HSF1). Four alternative splicing variants of HSF1 from pupal brains of H. armigera were identified, and subcellular localization analysis indicated that these variants were exclusively expressed in the nucleus. Real‐time PCR analysis showed that all of these variants were up‐regulated in diapause pupal brains, and their expression patterns were consistent with that of hsp70. Finally, promoter activity assay and Western blotting detection demonstrated that hsp70 was activated and up‐regulated by these variants. CONCLUSION: Expression of hsp70 in H. armigera during diapause is regulated by multiple alternatively spliced isoforms of HSF1. The results of this study may provide important information for understanding the regulatory mechanisms of hsps during insect diapause. © 2018 Society of Chemical Industry The aim of this study was to provide the basic information required to elucidate the role of HSF1 in pupal diapause of H. armigera, which could lay a foundation for the development of new pest control strategies. [ABSTRACT FROM AUTHOR]