Although the role of the Hippo signaling pathway in development and tumorigenesis has been extensively studied in multiple organs, its role in ovarian follicle development remains largely unknown. Here, we report that Yes‐Associated Protein 1 (YAP1), the major effector of Hippo signaling, is spatiotemporally expressed in ovarian granulosa cells and plays a critical role in the regulation of follicle development. We found that the active form of YAP1 (nuclear YAP1) was predominantly expressed in proliferative granulosa cells, whereas the inactive form of YAP1 (cytoplasmic YAP1) was mainly detected in luteal cells (terminally differentiated granulosa cells). Pharmacological inhibition of YAP1 activity disrupted mouse ovarian follicle development in vitro and in vivo. Foxl2 promoter–driven knockout of Yap1 in ovarian granulosa cells resulted in increased apoptosis of granulosa cells, decreased number of corpora lutea, reduced ovarian size, and subfertility in transgenic mice. However, Cyp19a1 promoter–driven knockout of Yap1 in differentiated granulosa cells of preovulatory follicles and luteal cells of corpora lutea had no effect on ovarian morphology and fertility. Mechanistic studies demonstrated that YAP1 interacted with epidermal growth factor receptor and TGF‐β signaling pathways to regulate granulosa cell proliferation, differentiation, and survival. Results from this study identify YAP1 as a critical regulator of granulosa cell proliferation and differentiation. Balanced expression and activation of YAP1 is essential for follicle development and successful reproduction. YAP1 is a promising target for treatment of subfertility associated with abnormal granulosa cell function.—Lv, X., He, C., Huang, C., Wang, H., Hua, G., Wang, Z., Zhou, J., Chen, X., Ma, B., Timm, B. K., Maclin, V., Dong, J., Rueda, B. R., Davis, J. S., Wang, C. Timely expression and activation of YAP1 in granulosa cells is essential for ovarian follicle development. FASEB J. 33, 10049–10064 (2019). www.fasebj.org

HPV infections are common in healthy women and only rarely cause cervical cancer, suggesting that individual genetic susceptibility may play a critical role in the establishment of persistent HPV infection and the development of cervical cancer. Here, we provide convincing in vitro and in vivo evidence showing that differential expression and activation of YAP1 oncogene determine individual susceptibility to HPV infection and cervical carcinogenesis. We found that hyperactivation of YAP1 in mouse cervical epithelium was sufficient to induce invasive cervical cancer. Cervical epithelial cell-specific HPV16 E6/E7 and YAP1 double-knockin mouse model demonstrated that high-risk HPV synergized with hyperactivated YAP1 to promote the initiation and progression of cervical cancer. Our mechanistic studies indicated that hyperactivation of YAP1 in cervical epithelial cells facilitated HPV infection by increasing the putative HPV receptor molecules and disrupting host cell innate immunity. Our finding reveals an unconventional mechanism for cervical carcinogenesis.

The poor efficacy of chimeric antigen receptor T-cell therapy (CAR T) for solid tumors is due to insufficient CAR T cell tumor infiltration, in vivo expansion, persistence, and effector function, as well as exhaustion, intrinsic target antigen heterogeneity or antigen loss of target cancer cells, and immunosuppressive tumor microenvironment (TME). Here we describe a broadly applicable nongenetic approach that simultaneously addresses the multiple challenges of CAR T as a therapy for solid tumors. The approach reprograms CAR T cells by exposing them to stressed target cancer cells which have been exposed to the cell stress inducer disulfiram (DSF) and copper (Cu)(DSF/Cu) plus ionizing irradiation (IR). The reprogrammed CAR T cells acquire early memory-like characteristics, potent cytotoxicity, enhanced in vivo expansion, persistence, and decreased exhaustion. Tumors stressed by DSF/Cu and IR also reprogram and reverse the immunosuppressive TME in humanized mice. The reprogrammed CAR T cells, derived from peripheral blood mononuclear cells of healthy donors or metastatic female breast cancer patients, induce robust, sustained memory and curative anti-solid tumor responses in multiple xenograft mouse models, establishing proof of concept for empowering CAR T by stressing tumor as a promising therapy for solid tumors.

Female subfertility is an increasing reproductive issue worldwide, which is partially related to abnormal ovarian follicular development. Granulosa cells (GCs), by providing the necessary physical support and microenvironment for follicular development, play critical roles in maintaining female fertility. We previously showed that ectopic expression of four and a half LIM domains 2 (FHL2) promoted ovarian granulosa cell tumor progression. However, its function in follicular development and fertility remains unknown. Here, we confirmed that FHL2 is highly expressed in human and mouse ovaries. FHL2 immunosignals were predominantly expressed in ovarian GCs. A Fhl2 knockout (KO) mouse model was generated to examine its roles in follicular development and fertility. Compared with wildtype, knockout of Fhl2 significantly decreased female litter size and offspring number. Furthermore, Fhl2 deficiency reduced ovarian size and impaired follicular development. RNA-sequencing analysis of GCs isolated from either KO or WT mice revealed that, Fhl2 deletion impaired multiple biological functions and signaling pathways, such as Ovarian Putative Early Atresia Granulosa Cell, ErbB, Hippo/YAP, etc. In vitro studies confirmed that FHL2 silencing suppressed GCs growth and EGF-induced GCs proliferation, while its overexpression promoted GC proliferation and decreased apoptosis. Mechanistic studies indicated that FHL2, via forming complexes with transcriptional factors AP-1 or NF-κB, regulated Egf and Egfr expression, respectively. Besides, FHL2 depletion decreased YAP1 expression, especially the active form of YAP1 (nuclear YAP1) in GCs of growing follicles. EGF, serving as an autocrine/paracrine factor, not only induced FHL2 expression and nuclear accumulation, but also stimulated YAP1 expression and activation. Collectively, our study suggests that FHL2 interacts with EGFR and Hippo/YAP signaling to regulate follicular development and maintain fertility. This study illuminates a novel mechanism for follicular development and a potential therapeutic target to address subfertility.