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Xie YC, Zhang HH, Li HJ, Zhang XY, Luo XM, Jiang MX, Zhang CX. Molting-related proteases in the brown planthopper, Nilaparvata lugens. Insect Biochem Mol Biol 2023; 152:103893. [PMID: 36513274 DOI: 10.1016/j.ibmb.2022.103893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 11/24/2022] [Accepted: 12/08/2022] [Indexed: 06/17/2023]
Abstract
Digestion and absorption of old cuticles during insect molting are necessary for new cuticle formation, during which complicated enzyme catalysis is essential. To date, a few carboxypeptidases, aminopeptidases and serine proteases (mostly trypsins) connected with cuticle digestion, zymogen activation and histological differentiation during the ecdysis of lepidopteran, dipteran and hymenopteran insects have been identified. However, little is known about these proteins in hemimetabolous insects. In this study, we identified 33 candidate trypsin and trypsin-like homologs, 14 metallocarboxypeptidase and 32 aminopeptidase genes in the brown planthopper Nilaparvata lugens, a hemipteran rice pest. Among the proteins encoded by these genes, 9 trypsin-like proteases, 3 metallocarboxypeptidases and 1 aminopeptidase were selected as potential procuticle hydrolases by bioinformatics analysis and in vivo validation. RNA interference targeting these genes demonstrated that 3 trypsin-like proteases (NlTrypsin-8, NlTrypsin-29 and NlTrypsin-32) genes and 1 metallocarboxypeptidase (NlCpB) gene were found to be essential for ecdysis in N. lugens; specifically, gene silencing led to incomplete cuticle degradation and arrested ecdysis, causing lethal morphological phenotype acquisition. Spatiotemporal expression profiling by quantitative PCR and western blotting revealed their specific expression in the integument and their periodic expression during each stadium, with a peak before ecdysis and eclosion. Transmission electron microscopy demonstrated corresponding ultrastructural defects after RNAi targeting, with NlCpB-silenced specimens having the most undigested old procuticles. Immunohistochemical staining revealed that NlTrypsin-8, NlTrypsin-29 and NlCpB were predominantly located in the exuvial space. This research further adds to our understanding of proteases and its potential role in insect ecdysis.
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Affiliation(s)
- Yu-Cheng Xie
- Institute of Insect Science, Zhejiang University, Hangzhou, 310058, China
| | - Hou-Hong Zhang
- Institute of Insect Science, Zhejiang University, Hangzhou, 310058, China
| | - Han-Jing Li
- Institute of Insect Science, Zhejiang University, Hangzhou, 310058, China
| | - Xiao-Ya Zhang
- Institute of Insect Science, Zhejiang University, Hangzhou, 310058, China
| | - Xu-Mei Luo
- Institute of Insect Science, Zhejiang University, Hangzhou, 310058, China
| | - Ming-Xing Jiang
- Institute of Insect Science, Zhejiang University, Hangzhou, 310058, China
| | - Chuan-Xi Zhang
- Institute of Insect Science, Zhejiang University, Hangzhou, 310058, China; State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China.
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Fricker LD, Lemos Duarte M, Jeltyi A, Lueptow L, Fakira AK, Tashima AK, Hochgeschwender U, Wetsel WC, Devi LA. Mice heterozygous for a null mutation of Cpe show reduced expression of carboxypeptidase E mRNA and enzyme activity but normal physiology, behavior, and levels of neuropeptides. Brain Res 2022; 1789:147951. [PMID: 35618016 DOI: 10.1016/j.brainres.2022.147951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/18/2022] [Accepted: 05/19/2022] [Indexed: 11/02/2022]
Abstract
Carboxypeptidase E (CPE) is an essential enzyme that contributes to the biosynthesis of the vast majority of neuropeptides and peptide hormones. There are several reports claiming that small decreases in CPE activity cause physiological changes in animals and/or cultured cells, but these studies did not provide evidence that neuropeptide levels were affected by decreased CPE activity. In the present study, we tested if CPE is a rate-limiting enzyme in neuropeptide production using CpeNeo mice, which contain a neomycin cassette within the Cpe gene that eliminates enzyme expression. Homozygous CpeNeo/Neo mice show defects found in Cpefat/fat and/or Cpe global knockout (KO) mice, including greatly decreased levels of most neuropeptides, severely impaired fertility, depressive-like behavior, adult-onset obesity, and anxiety-like behavior. Removal of the neomycin cassette with Flp recombinase under a germline promoter restored expression of CPE activity and resulted in normal behavioral and physiological properties, including levels of neuropeptides. Mice heterozygous for the CpeNeo allele have greatly reduced levels of Cpe mRNA and CPE-like enzymatic activity. Despite the decreased levels of Cpe expression, heterozygous CpeNeo mice are behaviorally and physiologically identical to wild-type mice, with normal levels of most neuropeptides. These results indicate that CPE is not a rate-limiting enzyme in the production of most neuropeptides, casting doubt upon studies claiming small decreases in CPE activity contribute to obesity or other physiological effects.
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Affiliation(s)
- Lloyd D Fricker
- Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461.
| | - Mariana Lemos Duarte
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, NY, NY, 10029.
| | - Andrei Jeltyi
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, NY, NY, 10029.
| | - Lindsay Lueptow
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, NY, NY, 10029.
| | - Amanda K Fakira
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, NY, NY, 10029.
| | - Alexandre K Tashima
- Department of Biochemistry, Escola Paulista de Medicina, Federal University of Sao Paulo, Sao Paulo, SP 04023-901, Brazil.
| | | | - William C Wetsel
- Departments of Psychiatry and Behavioral Sciences, Neurobiology, and Cell Biology, Duke University Medical Center, Durham, NC, 27710.
| | - Lakshmi A Devi
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, NY, NY, 10029.
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