Bmapaf-1 is Involved in the Response against BmNPV Infection by the Mitochondrial Apoptosis Pathway

Wang, Xue-Yang; Ding, Xinyi; Chen, Qian-Ying; Zhang, Kai-Xiang; Zhao, Chunli; Tang, Xudong; Wu, Yueming; Li, Muwang

doi:10.3390/insects11090647

Cited by 17 publications

(17 citation statements)

References 31 publications

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“…Biochemical tests showed that the expression of the CARD dimer of Apaf-1 could bind and activate the caspase-9 protein [ 12 ], and the expression of Apaf-1 without WD40 motif could lead to apoptosis independent of the presence of cytochrome c [ 13 ]. The Apaf-1 gene in Plutella xylostella and Bombyx mori have been cloned [ 14 , 15 ], but the structure and functions of Apaf-1 in Lepidopteran have not been investigated to date.…”

Section: Introductionmentioning

confidence: 99%

“…Apoptosis also plays an important role in insect physiology, e.g., development, tissue homeostasis, DNA damage response, and immune response [ 16 ]. Evidence suggests that the mitochondrial apoptosis pathway also exists in lepidopteran insects (e.g., Spodoptera frugiperda , Spodoptera exigua , Spodoptera litura , and Bombyx mori ), and studies from different laboratories have shown that cytochrome c plays an essential role during apoptosis [ 15 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Furthermore, two important caspases in the mitochondrial apoptosis pathway were identified in Lepidoptera.…”

Section: Introductionmentioning

confidence: 99%

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Identification and Functional Analysis of Apoptotic Protease Activating Factor-1 (Apaf-1) from Spodoptera litura

Yan

Lin

et al. 2021

Insects

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Apoptotic protease activating factor-1 (Apaf-1) is an adaptor molecule, essential for activating initiator caspase and downstream effector caspases, which directly cause apoptosis. In fruit flies, nematodes, and mammals, Apaf-1 has been extensively studied. However, the structure and function of Apaf-1 in Lepidoptera remain unclear. This study identified a novel Apaf-1 from Spodoptera litura, named Sl-Apaf-1. Sl-Apaf-1 contains three domains: a CARD domain, as well as NOD and WD motifs, and is very similar to mammalian Apaf-1. Interference of Sl-apaf-1 expression in SL-1 cells blocked apoptosis induced by actinomycin D. Overexpression of Sl-apaf-1 significantly enhances apoptosis induced by actinomycin D in Sf9/SL-1/U2OS cells, suggesting that the function of Sl-Apaf-1 is evolutionarily conserved. Furthermore, Sl-Apaf-1 could interact with Sl-caspase-5 (a homologue of mammalian caspase-9) and yielded a binding affinity of 1.37 × 106 M–1 according isothermal titration calorimetry assay. Initiator caspase (procaspase-5) of S. litura could be activated by Sl-Apaf-1 (without WD motif) in vitro, and the activated Sl-caspase-5 could cleave Sl-procaspase-1 (a homologue of caspase-3 in mammals), which directly caused apoptosis. This study demonstrates the key role of Sl-Apaf-1 in the apoptosis pathway, suggesting that the apoptosis pathway in Lepidopteran insects and mammals is conserved.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Identification and Functional Analysis of Apoptotic Protease Activating Factor-1 (Apaf-1) from Spodoptera litura

Yan

Lin

et al. 2021

Insects

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“…Once BVs enter a host cell via clathrin‐mediated endocytosis (Long et al, 2006), the permeability of the mitochondrial cell membrane will be changed (Sedlic et al, 2009) by some kind of unknown signal stimulated from BV, which further leads to the release of BmCytc into the cytoplasm (Pan et al, 2009). The released BmCytc activates BmApaf‐1 (Wang et al, 2020) and BmNc (Figures ). BmCas‐1 will be activated by the activated BmNc and will subsequently activate apoptosis to protect the host from virus infection (Figure 7).…”

Section: Discussionmentioning

confidence: 99%

“…The MAP, as one kind of apoptosis pathway, was involved in host defense BV‐eGFP infection by the release of Cytc into the cytoplasm from mitochondria to activate apoptosis (Wang, Wu, et al, 2019). Moreover, once Bmcytc enters the cytoplasm, its downstream genes are activated to defend BmNPV by regulating Bmapaf‐1 (Wang et al, 2020) and Bmcas‐Nc (Figures ). To confirm whether Bmcas‐1 is the final effector in charge of the activation of apoptosis in silkworm to defend against BmNPV, a series of experiments were designed and performed in this study.…”

Section: Discussionmentioning

confidence: 99%

Bmcas‐1 plays an important role in response against BmNPV infection in vitro

Wang

Zhao

Huang

et al. 2021

Arch Insect Biochem Physiol

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Apoptosis, as one kind of innate immune system, is involved in host response against pathogens innovation. Caspases play a vital role in the execution stage of host cell apoptosis. It has been reported that Bmcaspase‐1 (Bmcas‐1) has a close relationship with Bombyx mori nucleopolyhedrovirus (BmNPV) infection for its differentially expressed patterns after viral infection. However, its underlying response mechanism is still unclear. The significant differential expression of Bmcas‐1 in different tissues of differentially resistant strains revealed its vital role in BmNPV infection. To further validate its role in BmNPV infection, budded virus (BV)‐eGFP was analyzed after knockdown and overexpression of Bmcas‐1 by small interfering RNA and the pIZT‐mCherry vector, respectively. The reproduction of BV‐eGFP obviously increased at 72 h after knockdown of Bmcas‐1, and decreased after overexpression in BmN cells. Moreover, the conserved functional domain of Cas‐1 among different species and the closed evolutionary relationship of Cas‐1 in Lepidoptera hinted that Bmcas‐1 might be associated with apoptosis, and this was also validated by the apoptosis inducer, Silvestrol, and the inhibitor, Z‐DEVD‐FMK. Therefore, Bmcas‐1 plays an essential antiviral role by activating apoptosis, and this result lays a fundament for clarifying the molecular mechanism of silkworm in response against BmNPV infection and breeding of resistant strains.

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“…It has been proved that, Nosema bombycis infection inhibited the apoptosis of BmN cells, mainly by down‐regulating the expression of Apaf‐1 and cytochrome C to prevent the formation of apoptosomes, consequentially created a suitable intracellular environment for the proliferation of N. bombycis (He et al, 2015). In another report, BmApaf‐1 was involved in the response of silkworm against BmNPV ( B. mori nucleopolyhedrovirus) infection by the mitochondrial apoptosis pathway (Wang et al, 2020). Overexpression of BmApaf‐1 significantly inhibited the BmNPV infection in BmN cells, while knockdown of BmApaf‐1 with siRNA promoted the BmNPV infection.…”

Section: Discussionmentioning

confidence: 99%

Functional analysis of a putative Bombyx mori cypovirus miRNA BmCPV‐miR‐10 and its effect on virus replication

Wang

Zhao

et al. 2021

Insect Molecular Biology

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Bombyx mori cypovirus (BmCPV) is an important pathogen of silkworm (B. mori), the economically beneficial insect. The mechanism of its interaction with host immune defence system in the process of infection is still not yet completely clear. Researches have demonstrated that virus‐encoded microRNAs (miRNA) play a crucial role in regulating host–pathogen interaction, but few reports are available so far on miRNAs encoded by insect viruses, especially the RNA viruses. In this study, a putative miRNA encoded by the 10th segment of BmCPV genomic RNA, BmCPV‐miR‐10, was identified and functionally analysed. The expression of the putative BmCPV‐miR‐10 could be detected via stem‐loop RT‐PCR (reverse transcription‐Polymerase Chain Reaction) in the midgut of silkworm larvae infected with BmCPV. BmCSDE1 (B. mori cold shock domain E1 protein) gene was predicted to be a candidate target gene for BmCPV‐miR‐10 with the miRNA binding site located in 3′ untranslated region of its mRNA. The regulation effect of the putative BmCPV‐miR‐10 on BmCSDE1 was verified in HEK293 cells by lentiviral expression system, in BmN cells by transfecting BmCPV‐miR‐10 mimics. The qRT‐PCR (quantitative real‐time PCR) results showed that the putative BmCPV‐miR‐10 could suppress the expression of BmCSDE1. By injection of BmCPV‐miR‐10 mimics into the silkworm larvae infected with BmCPV, it was further proved that the putative BmCPV‐miR‐10 could suppress the expression of BmCSDE1 in vivo, then inhibit the expression of BmApaf‐1 (B. mori apoptotic protease activating factor 1), while enhance the replication of BmCPV genomic RNAs to a certain extent. These results implied that the putative BmCPV‐miR‐10 could down‐regulate the expression of BmCSDE1, then suppress the expression of BmApaf‐1, thereby created a favourable intracellular environment for virus replication and proliferation.

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Bmapaf-1 is Involved in the Response against BmNPV Infection by the Mitochondrial Apoptosis Pathway

Cited by 17 publications

References 31 publications

Identification and Functional Analysis of Apoptotic Protease Activating Factor-1 (Apaf-1) from Spodoptera litura

Identification and Functional Analysis of Apoptotic Protease Activating Factor-1 (Apaf-1) from Spodoptera litura

Bmcas‐1 plays an important role in response against BmNPV infection in vitro

Functional analysis of a putative Bombyx mori cypovirus miRNA BmCPV‐miR‐10 and its effect on virus replication

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