Limits...
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

The YAP-miR-130a-VGLL4 positive feedback loop mediates Hippo signaling. (A, B) Knockdown of YAP, TAZ and TEADs increases VGLL4 protein level. Cells were transfected with siRNAs (A) or infected with shRNA (B) and analyzed by immunoblotting. Cyr61 is a known YAP target and a positive control. (C) miR-130a blocks VGLL4 induction upon YAP and TAZ inhibition in HMLE cells. (D) The miR-130a sponge abrogates VGLL4 inhibition by YAP in HepG2 cells. (E) Knockdown of Lats1/2 represses VGLL4 protein level. Cells were transfected with siRNAs as indicated and analyzed by immunoblotting. (F) Inactivation of the Hippo pathway in vivo increases miR-130a and represses VGLL4 protein level. Control and albumin-Cre-mediated Mst1/2 conditional knockout livers were harvested at 2 months of age for analysis. (G) Loss of cell adhesion represses miR-130a in a Lats1/2-dependent manner. siRNA-transfected HMLE cells were cultured in adhesion “A” or in suspension “S” for 48 h for analysis of miR-130a level. (H, I) Cell suspension induces VGLL4 by inhibiting YAP and miR-130a. HMLE stable cells were transfected and cultured in adhesion or in suspension for 48 h and analyzed by immunoblotting. (J) miR-130a inhibits anoikis in cooperation with YAP. HMLE stable cells were subjected to suspension culture for 48 h. Anoikis rates were determined by Annexin V staining and FACS. (K) Inhibition of miR-130a promotes anoikis. HepG2 cells were transfected and analyzed as in J.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4559818&req=5

fig5: The YAP-miR-130a-VGLL4 positive feedback loop mediates Hippo signaling. (A, B) Knockdown of YAP, TAZ and TEADs increases VGLL4 protein level. Cells were transfected with siRNAs (A) or infected with shRNA (B) and analyzed by immunoblotting. Cyr61 is a known YAP target and a positive control. (C) miR-130a blocks VGLL4 induction upon YAP and TAZ inhibition in HMLE cells. (D) The miR-130a sponge abrogates VGLL4 inhibition by YAP in HepG2 cells. (E) Knockdown of Lats1/2 represses VGLL4 protein level. Cells were transfected with siRNAs as indicated and analyzed by immunoblotting. (F) Inactivation of the Hippo pathway in vivo increases miR-130a and represses VGLL4 protein level. Control and albumin-Cre-mediated Mst1/2 conditional knockout livers were harvested at 2 months of age for analysis. (G) Loss of cell adhesion represses miR-130a in a Lats1/2-dependent manner. siRNA-transfected HMLE cells were cultured in adhesion “A” or in suspension “S” for 48 h for analysis of miR-130a level. (H, I) Cell suspension induces VGLL4 by inhibiting YAP and miR-130a. HMLE stable cells were transfected and cultured in adhesion or in suspension for 48 h and analyzed by immunoblotting. (J) miR-130a inhibits anoikis in cooperation with YAP. HMLE stable cells were subjected to suspension culture for 48 h. Anoikis rates were determined by Annexin V staining and FACS. (K) Inhibition of miR-130a promotes anoikis. HepG2 cells were transfected and analyzed as in J.

Mentions: The above data suggests the possibility of a YAP-miR-130a-VGLL4 positive feedback loop acting downstream of Hippo signaling to mediate potent responses to stimuli. Such a mechanism predicts the Hippo pathway in control of VGLL4 protein level. Indeed, knockdown of YAP and TAZ or TEADs substantially increased VGLL4 protein levels in cancer and noncancerous cell lines from various tissue origins (Figure 5A, 5B and Supplementary information, Figure S5A, S5B), suggesting widespread existence of the mechanism. However, VGLL4 mRNA level and protein stability were not affected by YAP and TAZ knockdown (Supplementary information, Figure S5C, S5D). Furthermore, overexpression of WT YAP or the WW domain mutant but not the S94A mutant repressed VGLL4 protein level (Supplementary information, Figure S5E). In support of that miR-130a is the underlying mechanism for VGLL4 regulation by YAP, miR-130a mimic abrogated VGLL4 induction by YAP and TAZ knockdown (Figure 5C), and miR-130a inhibition rescued VGLL4 expression upon YAP activation (Figure 5D and Supplementary information, Figure S5F). Thus YAP-TEAD actively represses VGLL4 level through miR-130a.


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)

The YAP-miR-130a-VGLL4 positive feedback loop mediates Hippo signaling. (A, B) Knockdown of YAP, TAZ and TEADs increases VGLL4 protein level. Cells were transfected with siRNAs (A) or infected with shRNA (B) and analyzed by immunoblotting. Cyr61 is a known YAP target and a positive control. (C) miR-130a blocks VGLL4 induction upon YAP and TAZ inhibition in HMLE cells. (D) The miR-130a sponge abrogates VGLL4 inhibition by YAP in HepG2 cells. (E) Knockdown of Lats1/2 represses VGLL4 protein level. Cells were transfected with siRNAs as indicated and analyzed by immunoblotting. (F) Inactivation of the Hippo pathway in vivo increases miR-130a and represses VGLL4 protein level. Control and albumin-Cre-mediated Mst1/2 conditional knockout livers were harvested at 2 months of age for analysis. (G) Loss of cell adhesion represses miR-130a in a Lats1/2-dependent manner. siRNA-transfected HMLE cells were cultured in adhesion “A” or in suspension “S” for 48 h for analysis of miR-130a level. (H, I) Cell suspension induces VGLL4 by inhibiting YAP and miR-130a. HMLE stable cells were transfected and cultured in adhesion or in suspension for 48 h and analyzed by immunoblotting. (J) miR-130a inhibits anoikis in cooperation with YAP. HMLE stable cells were subjected to suspension culture for 48 h. Anoikis rates were determined by Annexin V staining and FACS. (K) Inhibition of miR-130a promotes anoikis. HepG2 cells were transfected and analyzed as in J.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4559818&req=5

fig5: The YAP-miR-130a-VGLL4 positive feedback loop mediates Hippo signaling. (A, B) Knockdown of YAP, TAZ and TEADs increases VGLL4 protein level. Cells were transfected with siRNAs (A) or infected with shRNA (B) and analyzed by immunoblotting. Cyr61 is a known YAP target and a positive control. (C) miR-130a blocks VGLL4 induction upon YAP and TAZ inhibition in HMLE cells. (D) The miR-130a sponge abrogates VGLL4 inhibition by YAP in HepG2 cells. (E) Knockdown of Lats1/2 represses VGLL4 protein level. Cells were transfected with siRNAs as indicated and analyzed by immunoblotting. (F) Inactivation of the Hippo pathway in vivo increases miR-130a and represses VGLL4 protein level. Control and albumin-Cre-mediated Mst1/2 conditional knockout livers were harvested at 2 months of age for analysis. (G) Loss of cell adhesion represses miR-130a in a Lats1/2-dependent manner. siRNA-transfected HMLE cells were cultured in adhesion “A” or in suspension “S” for 48 h for analysis of miR-130a level. (H, I) Cell suspension induces VGLL4 by inhibiting YAP and miR-130a. HMLE stable cells were transfected and cultured in adhesion or in suspension for 48 h and analyzed by immunoblotting. (J) miR-130a inhibits anoikis in cooperation with YAP. HMLE stable cells were subjected to suspension culture for 48 h. Anoikis rates were determined by Annexin V staining and FACS. (K) Inhibition of miR-130a promotes anoikis. HepG2 cells were transfected and analyzed as in J.
Mentions: The above data suggests the possibility of a YAP-miR-130a-VGLL4 positive feedback loop acting downstream of Hippo signaling to mediate potent responses to stimuli. Such a mechanism predicts the Hippo pathway in control of VGLL4 protein level. Indeed, knockdown of YAP and TAZ or TEADs substantially increased VGLL4 protein levels in cancer and noncancerous cell lines from various tissue origins (Figure 5A, 5B and Supplementary information, Figure S5A, S5B), suggesting widespread existence of the mechanism. However, VGLL4 mRNA level and protein stability were not affected by YAP and TAZ knockdown (Supplementary information, Figure S5C, S5D). Furthermore, overexpression of WT YAP or the WW domain mutant but not the S94A mutant repressed VGLL4 protein level (Supplementary information, Figure S5E). In support of that miR-130a is the underlying mechanism for VGLL4 regulation by YAP, miR-130a mimic abrogated VGLL4 induction by YAP and TAZ knockdown (Figure 5C), and miR-130a inhibition rescued VGLL4 expression upon YAP activation (Figure 5D and Supplementary information, Figure S5F). Thus YAP-TEAD actively represses VGLL4 level through miR-130a.

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