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A miR-130a-YAP positive feedback loop promotes organ size and tumorigenesis.

Shen S, Guo X, Yan H, Lu Y, Ji X, Li L, Liang T, Zhou D, Feng XH, Zhao JC, Yu J, Gong XG, Zhang L, Zhao B - Cell Res. (2015)

Bottom Line: Organ size determination is one of the most intriguing unsolved mysteries in biology.Here we report that the YAP signaling is sustained through a novel microRNA-dependent positive feedback loop. miR-130a, which is directly induced by YAP, could effectively repress VGLL4, an inhibitor of YAP activity, thereby amplifying the YAP signals.Furthermore, the Drosophila Hippo pathway target bantam functionally mimics miR-130a by repressing the VGLL4 homolog SdBP/Tgi.

View Article: PubMed Central - PubMed

Affiliation: Life Sciences Institute and Innovation Center for Cell Signaling Network Hangzhou, Zhejiang 310058, China.

ABSTRACT
Organ size determination is one of the most intriguing unsolved mysteries in biology. Aberrant activation of the major effector and transcription co-activator YAP in the Hippo pathway causes drastic organ enlargement in development and underlies tumorigenesis in many human cancers. However, how robust YAP activation is achieved during organ size control remains elusive. Here we report that the YAP signaling is sustained through a novel microRNA-dependent positive feedback loop. miR-130a, which is directly induced by YAP, could effectively repress VGLL4, an inhibitor of YAP activity, thereby amplifying the YAP signals. Inhibition of miR-130a reversed liver size enlargement induced by Hippo pathway inactivation and blocked YAP-induced tumorigenesis. Furthermore, the Drosophila Hippo pathway target bantam functionally mimics miR-130a by repressing the VGLL4 homolog SdBP/Tgi. These findings reveal an evolutionarily conserved positive feedback mechanism underlying robustness of the Hippo pathway in size control and tumorigenesis.

No MeSH data available.


Related in: MedlinePlus

miR-130a in liver tumorigenesis and size control. (A) Schematic of liver tumorigenesis model by the hydrodynamic injection method. (B) YAP-5SA induces liver tumorigenesis. Control and YAP-5SA-injected livers 100 days post-injection are shown. Arrowheads indicate tumors. (C) Activation of miR-130a and inhibition of VGLL4 protein levels in YAP-induced liver tumors. YAP-5SA-induced tumors and adjacent normal tissues from 3 mice were processed for analysis. (D) YAP-induced tumorigenesis is repressed by VGLL4 and promoted by miR-130a. YAP-5SA was expressed alone or together with VGLL4 or pre-miR130a by hydrodynamic injection. Tumorigenesis was analyzed at 70 or 110 days after injection. Boxed areas are enlarged on the right. H&E-stained D70 liver sections are also shown. Green arrowheads indicate lesions. (E, F) miR-130a sponge abrogates liver enlargement (E) and hepatocyte proliferation (F) induced by Mst1/2 knockout. Mice of the indicated genotypes were transduced with adenoviral Cre and miR-130a sponge as indicated. Mice were sacrificed 9 days after injection for liver/body weight ratios (E) and Ki67 staining (F, green). P-values were calculated by student's t-test. (G) miR-130a sponge abrogates VGLL4 repression and YAP target gene induction by Mst1/2 knockout. Livers from experiments described in E were analyzed. Compare control and Mst1/2 knockout groups, the change of all three target genes have a P-value < 0.001. Compare Mst1/2 knockout with Mst1/2 knockout plus Ad-130a sp groups, the P-values for gene expression changes are as follows: CTGF, < 0.001; Cyr61, < 0.05; Inhba, < 0.01.
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fig6: miR-130a in liver tumorigenesis and size control. (A) Schematic of liver tumorigenesis model by the hydrodynamic injection method. (B) YAP-5SA induces liver tumorigenesis. Control and YAP-5SA-injected livers 100 days post-injection are shown. Arrowheads indicate tumors. (C) Activation of miR-130a and inhibition of VGLL4 protein levels in YAP-induced liver tumors. YAP-5SA-induced tumors and adjacent normal tissues from 3 mice were processed for analysis. (D) YAP-induced tumorigenesis is repressed by VGLL4 and promoted by miR-130a. YAP-5SA was expressed alone or together with VGLL4 or pre-miR130a by hydrodynamic injection. Tumorigenesis was analyzed at 70 or 110 days after injection. Boxed areas are enlarged on the right. H&E-stained D70 liver sections are also shown. Green arrowheads indicate lesions. (E, F) miR-130a sponge abrogates liver enlargement (E) and hepatocyte proliferation (F) induced by Mst1/2 knockout. Mice of the indicated genotypes were transduced with adenoviral Cre and miR-130a sponge as indicated. Mice were sacrificed 9 days after injection for liver/body weight ratios (E) and Ki67 staining (F, green). P-values were calculated by student's t-test. (G) miR-130a sponge abrogates VGLL4 repression and YAP target gene induction by Mst1/2 knockout. Livers from experiments described in E were analyzed. Compare control and Mst1/2 knockout groups, the change of all three target genes have a P-value < 0.001. Compare Mst1/2 knockout with Mst1/2 knockout plus Ad-130a sp groups, the P-values for gene expression changes are as follows: CTGF, < 0.001; Cyr61, < 0.05; Inhba, < 0.01.

Mentions: We further investigated the miR-130a-mediated positive feedback mechanism in mouse liver. Genetic inactivation of Hippo pathway components such as Mst1/2, Sav and NF2 potently induces liver tumorigenesis26,32,39,40,41,42. However, except for NF2, germline mutations of these genes have not been reported in human cancer. This suggests that defects in this pathway in cancer are more commonly somatic and mosaic. To more accurately model this situation, we used the hydrodynamic injection method to deliver transposon plasmids encoding YAP and the piggyBac transposase, which led to stable mosaic YAP expression in hepatocytes (Figure 6A). Despite recent report using similar method suggesting that YAP-S127A alone was not tumorigenic43, the YAP-5SA mutant induced large tumors 100 days post-injection (Figure 6B and Supplementary information, Figure S6A). This result indicates that aberrant YAP activation alone is sufficient to drive liver tumorigenesis in a normal tissue microenvironment. Obviously, the repression imposed on YAP by VGLL4 must be circumvented. Indeed, in YAP-induced tumors, the expression of miR-130a was elevated and VGLL4 protein but not mRNA level was repressed (Figure 6C and Supplementary information, Figure S6B). To investigate the role of VGLL4 and miR-130a in YAP-induced liver tumorigenesis, we co-expressed YAP-5SA with VGLL4 or miR-130a. In YAP-5SA injected livers, small tumors were often obvious at day 70 (D70) after injection and several big tumors were often seen at D110 after injection (Figure 6D). However, co-expression of VGLL4 eliminated tumors at D70 and small tumors were only occasionally seen at D110 (Figure 6D). The lack of VGLL4 expression in these tumors suggested an origin from cells expressing only YAP-5SA (Supplementary information, Figure S6C). Thus VGLL4 markedly repressed YAP-induced liver tumorigenesis. In contrast, co-injection of YAP-5SA and pre-miR-130a induced not only small tumors but also numerous hyperplastic foci by D70 (Figure 6D). Consistently, these livers also showed much more tumors at D110 and some mice were moribund at the time (Figure 6D). Thus miR-130a promoted liver tumorigenesis induced by YAP.


A miR-130a-YAP positive feedback loop promotes organ size and tumorigenesis.

Shen S, Guo X, Yan H, Lu Y, Ji X, Li L, Liang T, Zhou D, Feng XH, Zhao JC, Yu J, Gong XG, Zhang L, Zhao B - Cell Res. (2015)

miR-130a in liver tumorigenesis and size control. (A) Schematic of liver tumorigenesis model by the hydrodynamic injection method. (B) YAP-5SA induces liver tumorigenesis. Control and YAP-5SA-injected livers 100 days post-injection are shown. Arrowheads indicate tumors. (C) Activation of miR-130a and inhibition of VGLL4 protein levels in YAP-induced liver tumors. YAP-5SA-induced tumors and adjacent normal tissues from 3 mice were processed for analysis. (D) YAP-induced tumorigenesis is repressed by VGLL4 and promoted by miR-130a. YAP-5SA was expressed alone or together with VGLL4 or pre-miR130a by hydrodynamic injection. Tumorigenesis was analyzed at 70 or 110 days after injection. Boxed areas are enlarged on the right. H&E-stained D70 liver sections are also shown. Green arrowheads indicate lesions. (E, F) miR-130a sponge abrogates liver enlargement (E) and hepatocyte proliferation (F) induced by Mst1/2 knockout. Mice of the indicated genotypes were transduced with adenoviral Cre and miR-130a sponge as indicated. Mice were sacrificed 9 days after injection for liver/body weight ratios (E) and Ki67 staining (F, green). P-values were calculated by student's t-test. (G) miR-130a sponge abrogates VGLL4 repression and YAP target gene induction by Mst1/2 knockout. Livers from experiments described in E were analyzed. Compare control and Mst1/2 knockout groups, the change of all three target genes have a P-value < 0.001. Compare Mst1/2 knockout with Mst1/2 knockout plus Ad-130a sp groups, the P-values for gene expression changes are as follows: CTGF, < 0.001; Cyr61, < 0.05; Inhba, < 0.01.
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fig6: miR-130a in liver tumorigenesis and size control. (A) Schematic of liver tumorigenesis model by the hydrodynamic injection method. (B) YAP-5SA induces liver tumorigenesis. Control and YAP-5SA-injected livers 100 days post-injection are shown. Arrowheads indicate tumors. (C) Activation of miR-130a and inhibition of VGLL4 protein levels in YAP-induced liver tumors. YAP-5SA-induced tumors and adjacent normal tissues from 3 mice were processed for analysis. (D) YAP-induced tumorigenesis is repressed by VGLL4 and promoted by miR-130a. YAP-5SA was expressed alone or together with VGLL4 or pre-miR130a by hydrodynamic injection. Tumorigenesis was analyzed at 70 or 110 days after injection. Boxed areas are enlarged on the right. H&E-stained D70 liver sections are also shown. Green arrowheads indicate lesions. (E, F) miR-130a sponge abrogates liver enlargement (E) and hepatocyte proliferation (F) induced by Mst1/2 knockout. Mice of the indicated genotypes were transduced with adenoviral Cre and miR-130a sponge as indicated. Mice were sacrificed 9 days after injection for liver/body weight ratios (E) and Ki67 staining (F, green). P-values were calculated by student's t-test. (G) miR-130a sponge abrogates VGLL4 repression and YAP target gene induction by Mst1/2 knockout. Livers from experiments described in E were analyzed. Compare control and Mst1/2 knockout groups, the change of all three target genes have a P-value < 0.001. Compare Mst1/2 knockout with Mst1/2 knockout plus Ad-130a sp groups, the P-values for gene expression changes are as follows: CTGF, < 0.001; Cyr61, < 0.05; Inhba, < 0.01.
Mentions: We further investigated the miR-130a-mediated positive feedback mechanism in mouse liver. Genetic inactivation of Hippo pathway components such as Mst1/2, Sav and NF2 potently induces liver tumorigenesis26,32,39,40,41,42. However, except for NF2, germline mutations of these genes have not been reported in human cancer. This suggests that defects in this pathway in cancer are more commonly somatic and mosaic. To more accurately model this situation, we used the hydrodynamic injection method to deliver transposon plasmids encoding YAP and the piggyBac transposase, which led to stable mosaic YAP expression in hepatocytes (Figure 6A). Despite recent report using similar method suggesting that YAP-S127A alone was not tumorigenic43, the YAP-5SA mutant induced large tumors 100 days post-injection (Figure 6B and Supplementary information, Figure S6A). This result indicates that aberrant YAP activation alone is sufficient to drive liver tumorigenesis in a normal tissue microenvironment. Obviously, the repression imposed on YAP by VGLL4 must be circumvented. Indeed, in YAP-induced tumors, the expression of miR-130a was elevated and VGLL4 protein but not mRNA level was repressed (Figure 6C and Supplementary information, Figure S6B). To investigate the role of VGLL4 and miR-130a in YAP-induced liver tumorigenesis, we co-expressed YAP-5SA with VGLL4 or miR-130a. In YAP-5SA injected livers, small tumors were often obvious at day 70 (D70) after injection and several big tumors were often seen at D110 after injection (Figure 6D). However, co-expression of VGLL4 eliminated tumors at D70 and small tumors were only occasionally seen at D110 (Figure 6D). The lack of VGLL4 expression in these tumors suggested an origin from cells expressing only YAP-5SA (Supplementary information, Figure S6C). Thus VGLL4 markedly repressed YAP-induced liver tumorigenesis. In contrast, co-injection of YAP-5SA and pre-miR-130a induced not only small tumors but also numerous hyperplastic foci by D70 (Figure 6D). Consistently, these livers also showed much more tumors at D110 and some mice were moribund at the time (Figure 6D). Thus miR-130a promoted liver tumorigenesis induced by YAP.

Bottom Line: Organ size determination is one of the most intriguing unsolved mysteries in biology.Here we report that the YAP signaling is sustained through a novel microRNA-dependent positive feedback loop. miR-130a, which is directly induced by YAP, could effectively repress VGLL4, an inhibitor of YAP activity, thereby amplifying the YAP signals.Furthermore, the Drosophila Hippo pathway target bantam functionally mimics miR-130a by repressing the VGLL4 homolog SdBP/Tgi.

View Article: PubMed Central - PubMed

Affiliation: Life Sciences Institute and Innovation Center for Cell Signaling Network Hangzhou, Zhejiang 310058, China.

ABSTRACT
Organ size determination is one of the most intriguing unsolved mysteries in biology. Aberrant activation of the major effector and transcription co-activator YAP in the Hippo pathway causes drastic organ enlargement in development and underlies tumorigenesis in many human cancers. However, how robust YAP activation is achieved during organ size control remains elusive. Here we report that the YAP signaling is sustained through a novel microRNA-dependent positive feedback loop. miR-130a, which is directly induced by YAP, could effectively repress VGLL4, an inhibitor of YAP activity, thereby amplifying the YAP signals. Inhibition of miR-130a reversed liver size enlargement induced by Hippo pathway inactivation and blocked YAP-induced tumorigenesis. Furthermore, the Drosophila Hippo pathway target bantam functionally mimics miR-130a by repressing the VGLL4 homolog SdBP/Tgi. These findings reveal an evolutionarily conserved positive feedback mechanism underlying robustness of the Hippo pathway in size control and tumorigenesis.

No MeSH data available.


Related in: MedlinePlus