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Pelle Modulates dFoxO-Mediated Cell Death in Drosophila.

Wu C, Chen Y, Wang F, Chen C, Zhang S, Li C, Li W, Wu S, Xue L - PLoS Genet. (2015)

Bottom Line: Interleukin-1 receptor-associated kinases (IRAKs) are crucial mediators of the IL-1R/TLR signaling pathways that regulate the immune and inflammation response in mammals.Finally, Pll physically interacts with dFoxO and phosphorylates dFoxO directly.This study not only identifies a previously unknown physiological function of pll in cell death, but also shed light on the mechanism of IRAKs in cell survival/death during tumorigenesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Interventional Radiology, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai, China.

ABSTRACT
Interleukin-1 receptor-associated kinases (IRAKs) are crucial mediators of the IL-1R/TLR signaling pathways that regulate the immune and inflammation response in mammals. Recent studies also suggest a critical role of IRAKs in tumor development, though the underlying mechanism remains elusive. Pelle is the sole Drosophila IRAK homolog implicated in the conserved Toll pathway that regulates Dorsal/Ventral patterning, innate immune response, muscle development and axon guidance. Here we report a novel function of pll in modulating apoptotic cell death, which is independent of the Toll pathway. We found that loss of pll results in reduced size in wing tissue, which is caused by a reduction in cell number but not cell size. Depletion of pll up-regulates the transcription of pro-apoptotic genes, and triggers caspase activation and cell death. The transcription factor dFoxO is required for loss-of-pll induced cell death. Furthermore, loss of pll activates dFoxO, promotes its translocation from cytoplasm to nucleus, and up-regulates the transcription of its target gene Thor/4E-BP. Finally, Pll physically interacts with dFoxO and phosphorylates dFoxO directly. This study not only identifies a previously unknown physiological function of pll in cell death, but also shed light on the mechanism of IRAKs in cell survival/death during tumorigenesis.

No MeSH data available.


Related in: MedlinePlus

dFoxO is required for loss-of-pll induced wing phenotypes.(A-R) Light micrographs showing Drosophila adult wings, anterior is to the left and distal up. Compared with controls (A, G and M), the wing phenotypes of ptc>pll-IRV2889 (B), Sd>pll-IRV2889 (H) and Omb>pll-IRV2889 (N) flies were suppressed by knocking-down dFoxO (D, J and P) or removing one or both copies of dFoxO (E, F, K, L, Q and R), but not by expressing a GFP-IR (C, I and O). In A-F, the lower panels are high magnification of the boxed areas in upper panels. (S-U) Statistical analysis of the ACV phenotype (S) and the adult wing size/wild type (WT) (T and U) as shown in figures A-F, G-L and M-R respectively. One-way ANOVA with Bonferroni multiple comparison test was used to compute P-values, significance is indicated with asterisks (*** P<0.001). ns stands for not significant. Detailed genotypes: (A) ptc-Gal4/+ (B) ptc-Gal4/UAS-pll-IRV2889 (C) ptc-Gal4/UAS-pll-IRV2889/+; UAS-GFP-IR/+ (D) ptc-Gal4/UAS-pll-IRV2889/+; UAS-dFoxO-IR/+ (E) ptc-Gal4/UAS-pll-IRV2889/+; dFoxOΔ94/+ (F) ptc-Gal4/UAS-pll-IRV2889/+; dFoxOΔ94/Δ94 (G) Sd-Gal4/+ (H) Sd-Gal4/+; UAS-pll-IRV2889/+ (I) Sd-Gal4/+; UAS-pll-IRV2889/+; UAS-GFP-IR/+ (J) Sd-Gal4/+; UAS-pll-IRV2889/+; UAS-dFoxO-IR/+ (K) Sd-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/+ (L) Sd-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/Δ94 (M) Omb-Gal4/+ (N) Omb-Gal4/+; UAS-pll-IRV2889/+ (O) Omb-Gal4/+; UAS-pll-IRV2889/+; UAS-GFP-IR/+ (P) Omb-Gal4/+; UAS-pll-IRV2889/+; UAS-dFoxO-IR/+ (Q) Omb-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/+ (R) Omb-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/Δ94.
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pgen.1005589.g007: dFoxO is required for loss-of-pll induced wing phenotypes.(A-R) Light micrographs showing Drosophila adult wings, anterior is to the left and distal up. Compared with controls (A, G and M), the wing phenotypes of ptc>pll-IRV2889 (B), Sd>pll-IRV2889 (H) and Omb>pll-IRV2889 (N) flies were suppressed by knocking-down dFoxO (D, J and P) or removing one or both copies of dFoxO (E, F, K, L, Q and R), but not by expressing a GFP-IR (C, I and O). In A-F, the lower panels are high magnification of the boxed areas in upper panels. (S-U) Statistical analysis of the ACV phenotype (S) and the adult wing size/wild type (WT) (T and U) as shown in figures A-F, G-L and M-R respectively. One-way ANOVA with Bonferroni multiple comparison test was used to compute P-values, significance is indicated with asterisks (*** P<0.001). ns stands for not significant. Detailed genotypes: (A) ptc-Gal4/+ (B) ptc-Gal4/UAS-pll-IRV2889 (C) ptc-Gal4/UAS-pll-IRV2889/+; UAS-GFP-IR/+ (D) ptc-Gal4/UAS-pll-IRV2889/+; UAS-dFoxO-IR/+ (E) ptc-Gal4/UAS-pll-IRV2889/+; dFoxOΔ94/+ (F) ptc-Gal4/UAS-pll-IRV2889/+; dFoxOΔ94/Δ94 (G) Sd-Gal4/+ (H) Sd-Gal4/+; UAS-pll-IRV2889/+ (I) Sd-Gal4/+; UAS-pll-IRV2889/+; UAS-GFP-IR/+ (J) Sd-Gal4/+; UAS-pll-IRV2889/+; UAS-dFoxO-IR/+ (K) Sd-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/+ (L) Sd-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/Δ94 (M) Omb-Gal4/+ (N) Omb-Gal4/+; UAS-pll-IRV2889/+ (O) Omb-Gal4/+; UAS-pll-IRV2889/+; UAS-GFP-IR/+ (P) Omb-Gal4/+; UAS-pll-IRV2889/+; UAS-dFoxO-IR/+ (Q) Omb-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/+ (R) Omb-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/Δ94.

Mentions: To understand the mechanism by which loss of pll induces caspase-dependent cell death, we considered the transcription factor dFoxO as a putative downstream factor negatively regulated by Pll. Firstly, dFoxO is known to be negatively regulated by other kinase, e.g. Akt [26,28]. Secondly, previous studies reported that dFoxO is required for the apoptotic response and regulates the expression of pro-apoptotic gene hid [30]. Thirdly, we have previously observed a similar loss-of-ACV phenotype resulted from dFoxO expression driven by ptc-Gal4 driver [33]. In support of the assumption, we found that loss-of-pll triggered cell death in the wing pouch, as detected by AO staining (Fig 5B and 5M) and cleaved caspase-3 (CC-3) antibody (Fig 5H and 5N), was notably blocked by RNAi-mediated depletion of dFoxO, and in heterozygous or homozygous dFoxOΔ94 mutants (Fig 5D–5F and 5J–5N). Furthermore, depletion of pll induced various wing defects are suppressed by loss of dFoxO, either by mutation or expression of RNAi (Fig 7; S6 Fig). A GFP RNAi was employed as a negative control (Fig 5C and 5I; Fig 7C, 7I and 7O). The knock-down efficiency of dFoxO RNAi lines and the dFoxO mRNA level in dFoxOΔ94 mutants have been previously verified [33,44,45]. Consistently, expression of dFoxO driven by ptc-Gal4 (ptc>dFoxO) recapitulates the loss-of-ACV phenotype in ptc>pll-IR flies (S7A Fig). However, the ptc>dFoxO triggered loss-of-ACV phenotype cannot be suppressed by co-expressing Pll (S7B and S7C Fig), confirming that dFoxO acts downstream of Pll. Therefore, we conclude that loss of pll induces dFoxO-dependent cell death in wing development.


Pelle Modulates dFoxO-Mediated Cell Death in Drosophila.

Wu C, Chen Y, Wang F, Chen C, Zhang S, Li C, Li W, Wu S, Xue L - PLoS Genet. (2015)

dFoxO is required for loss-of-pll induced wing phenotypes.(A-R) Light micrographs showing Drosophila adult wings, anterior is to the left and distal up. Compared with controls (A, G and M), the wing phenotypes of ptc>pll-IRV2889 (B), Sd>pll-IRV2889 (H) and Omb>pll-IRV2889 (N) flies were suppressed by knocking-down dFoxO (D, J and P) or removing one or both copies of dFoxO (E, F, K, L, Q and R), but not by expressing a GFP-IR (C, I and O). In A-F, the lower panels are high magnification of the boxed areas in upper panels. (S-U) Statistical analysis of the ACV phenotype (S) and the adult wing size/wild type (WT) (T and U) as shown in figures A-F, G-L and M-R respectively. One-way ANOVA with Bonferroni multiple comparison test was used to compute P-values, significance is indicated with asterisks (*** P<0.001). ns stands for not significant. Detailed genotypes: (A) ptc-Gal4/+ (B) ptc-Gal4/UAS-pll-IRV2889 (C) ptc-Gal4/UAS-pll-IRV2889/+; UAS-GFP-IR/+ (D) ptc-Gal4/UAS-pll-IRV2889/+; UAS-dFoxO-IR/+ (E) ptc-Gal4/UAS-pll-IRV2889/+; dFoxOΔ94/+ (F) ptc-Gal4/UAS-pll-IRV2889/+; dFoxOΔ94/Δ94 (G) Sd-Gal4/+ (H) Sd-Gal4/+; UAS-pll-IRV2889/+ (I) Sd-Gal4/+; UAS-pll-IRV2889/+; UAS-GFP-IR/+ (J) Sd-Gal4/+; UAS-pll-IRV2889/+; UAS-dFoxO-IR/+ (K) Sd-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/+ (L) Sd-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/Δ94 (M) Omb-Gal4/+ (N) Omb-Gal4/+; UAS-pll-IRV2889/+ (O) Omb-Gal4/+; UAS-pll-IRV2889/+; UAS-GFP-IR/+ (P) Omb-Gal4/+; UAS-pll-IRV2889/+; UAS-dFoxO-IR/+ (Q) Omb-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/+ (R) Omb-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/Δ94.
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pgen.1005589.g007: dFoxO is required for loss-of-pll induced wing phenotypes.(A-R) Light micrographs showing Drosophila adult wings, anterior is to the left and distal up. Compared with controls (A, G and M), the wing phenotypes of ptc>pll-IRV2889 (B), Sd>pll-IRV2889 (H) and Omb>pll-IRV2889 (N) flies were suppressed by knocking-down dFoxO (D, J and P) or removing one or both copies of dFoxO (E, F, K, L, Q and R), but not by expressing a GFP-IR (C, I and O). In A-F, the lower panels are high magnification of the boxed areas in upper panels. (S-U) Statistical analysis of the ACV phenotype (S) and the adult wing size/wild type (WT) (T and U) as shown in figures A-F, G-L and M-R respectively. One-way ANOVA with Bonferroni multiple comparison test was used to compute P-values, significance is indicated with asterisks (*** P<0.001). ns stands for not significant. Detailed genotypes: (A) ptc-Gal4/+ (B) ptc-Gal4/UAS-pll-IRV2889 (C) ptc-Gal4/UAS-pll-IRV2889/+; UAS-GFP-IR/+ (D) ptc-Gal4/UAS-pll-IRV2889/+; UAS-dFoxO-IR/+ (E) ptc-Gal4/UAS-pll-IRV2889/+; dFoxOΔ94/+ (F) ptc-Gal4/UAS-pll-IRV2889/+; dFoxOΔ94/Δ94 (G) Sd-Gal4/+ (H) Sd-Gal4/+; UAS-pll-IRV2889/+ (I) Sd-Gal4/+; UAS-pll-IRV2889/+; UAS-GFP-IR/+ (J) Sd-Gal4/+; UAS-pll-IRV2889/+; UAS-dFoxO-IR/+ (K) Sd-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/+ (L) Sd-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/Δ94 (M) Omb-Gal4/+ (N) Omb-Gal4/+; UAS-pll-IRV2889/+ (O) Omb-Gal4/+; UAS-pll-IRV2889/+; UAS-GFP-IR/+ (P) Omb-Gal4/+; UAS-pll-IRV2889/+; UAS-dFoxO-IR/+ (Q) Omb-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/+ (R) Omb-Gal4/+; UAS-pll-IRV2889/+; dFoxOΔ94/Δ94.
Mentions: To understand the mechanism by which loss of pll induces caspase-dependent cell death, we considered the transcription factor dFoxO as a putative downstream factor negatively regulated by Pll. Firstly, dFoxO is known to be negatively regulated by other kinase, e.g. Akt [26,28]. Secondly, previous studies reported that dFoxO is required for the apoptotic response and regulates the expression of pro-apoptotic gene hid [30]. Thirdly, we have previously observed a similar loss-of-ACV phenotype resulted from dFoxO expression driven by ptc-Gal4 driver [33]. In support of the assumption, we found that loss-of-pll triggered cell death in the wing pouch, as detected by AO staining (Fig 5B and 5M) and cleaved caspase-3 (CC-3) antibody (Fig 5H and 5N), was notably blocked by RNAi-mediated depletion of dFoxO, and in heterozygous or homozygous dFoxOΔ94 mutants (Fig 5D–5F and 5J–5N). Furthermore, depletion of pll induced various wing defects are suppressed by loss of dFoxO, either by mutation or expression of RNAi (Fig 7; S6 Fig). A GFP RNAi was employed as a negative control (Fig 5C and 5I; Fig 7C, 7I and 7O). The knock-down efficiency of dFoxO RNAi lines and the dFoxO mRNA level in dFoxOΔ94 mutants have been previously verified [33,44,45]. Consistently, expression of dFoxO driven by ptc-Gal4 (ptc>dFoxO) recapitulates the loss-of-ACV phenotype in ptc>pll-IR flies (S7A Fig). However, the ptc>dFoxO triggered loss-of-ACV phenotype cannot be suppressed by co-expressing Pll (S7B and S7C Fig), confirming that dFoxO acts downstream of Pll. Therefore, we conclude that loss of pll induces dFoxO-dependent cell death in wing development.

Bottom Line: Interleukin-1 receptor-associated kinases (IRAKs) are crucial mediators of the IL-1R/TLR signaling pathways that regulate the immune and inflammation response in mammals.Finally, Pll physically interacts with dFoxO and phosphorylates dFoxO directly.This study not only identifies a previously unknown physiological function of pll in cell death, but also shed light on the mechanism of IRAKs in cell survival/death during tumorigenesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Interventional Radiology, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai, China.

ABSTRACT
Interleukin-1 receptor-associated kinases (IRAKs) are crucial mediators of the IL-1R/TLR signaling pathways that regulate the immune and inflammation response in mammals. Recent studies also suggest a critical role of IRAKs in tumor development, though the underlying mechanism remains elusive. Pelle is the sole Drosophila IRAK homolog implicated in the conserved Toll pathway that regulates Dorsal/Ventral patterning, innate immune response, muscle development and axon guidance. Here we report a novel function of pll in modulating apoptotic cell death, which is independent of the Toll pathway. We found that loss of pll results in reduced size in wing tissue, which is caused by a reduction in cell number but not cell size. Depletion of pll up-regulates the transcription of pro-apoptotic genes, and triggers caspase activation and cell death. The transcription factor dFoxO is required for loss-of-pll induced cell death. Furthermore, loss of pll activates dFoxO, promotes its translocation from cytoplasm to nucleus, and up-regulates the transcription of its target gene Thor/4E-BP. Finally, Pll physically interacts with dFoxO and phosphorylates dFoxO directly. This study not only identifies a previously unknown physiological function of pll in cell death, but also shed light on the mechanism of IRAKs in cell survival/death during tumorigenesis.

No MeSH data available.


Related in: MedlinePlus