scholarly journals The Hippo Pathway in Cardiac Regeneration and Homeostasis: New Perspectives for Cell-Free Therapy in the Injured Heart

Biomolecules ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1024
Author(s):  
Mingjie Zheng ◽  
Joan Jacob ◽  
Shao-Hsi Hung ◽  
Jun Wang

Intractable cardiovascular diseases are leading causes of mortality around the world. Adult mammalian hearts have poor regenerative capacity and are not capable of self-repair after injury. Recent studies of cell-free therapeutics such as those designed to stimulate endogenous cardiac regeneration have uncovered new feasible therapeutic avenues for cardiac repair. The Hippo pathway, a fundamental pathway with pivotal roles in cell proliferation, survival and differentiation, has tremendous potential for therapeutic manipulation in cardiac regeneration. In this review, we summarize the most recent studies that have revealed the function of the Hippo pathway in heart regeneration and homeostasis. In particular, we discuss the molecular mechanisms of how the Hippo pathway maintains cardiac homeostasis by directing cardiomyocyte chromatin remodeling and regulating the cell-cell communication between cardiomyocytes and non-cardiomyocytes in the heart.

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Masahide Sakabe ◽  
Aishlin Hassan ◽  
Mei Xin

Introduction: The regeneration potential in the adult mammalian heart is very limited due to the cessation of cardiomyocyte proliferation shortly after birth. Recent studies have revealed that changes after birth such as metabolic state, oxygen level, cardiomyocyte structure and maturity, immune system and polyploidy are among the factors contributing to the loss of the regenerative potential in the heart. The mechanisms that regulate the cardiac regenerative window are not well understood. Here we report that G-protein mediated signaling regulates Hippo-YAP in neonatal cardiomyocyte proliferation and heart regeneration through Rho activity. Hypothesis: Gas encoded by the Gnas gene, a downstream effector of beta-adrenergic receptor (βAR) inhibits cardiomyocyte proliferation via regulation of YAP activity. Methods: We pharmacologically inhibited the G protein coupled receptor mediated β adrenergic signaling with a β-blocker (metoprolol) at early postnatal stages, and genetically by deleting Gnas in the heart with αMHC-Cre. We accessed the cardiomyocyte proliferation, heart regeneration in these mice and elucidated molecular mechanisms. Results: We found that β-blocker enhanced cardiomyocyte proliferation and promoted cardiac regeneration post cardiac injury with improved cardiac function. Consistent with β-blocker treated mice, mice lacking Gnas in cardiomyocytes exhibited enlarged hearts with an increase in cardiomyocyte proliferation. RNA-seq analysis revealed that these cardiomyocytes maintained an immature status even at young-adult age. The genes associated with mitochondrial oxidative metabolism, the major energy source for mature cardiomyocytes, were downregulated. Moreover, YAP activity was upregulated in both cases. We also found that loss of Gαs function caused upregulation of RhoA activity, and inhibitor of Rho signaling pathway suppressed the YAP activity in cardiomyocytes. Conclusions: Our study reveals that Gαs negatively regulate cardiomyocyte proliferation and provides mechanistic insight for β-blocker treatment as a strategy for inducing cardiac dedifferentiation and proliferation in injured heart.


2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Yuka Morikawa ◽  
John Leach ◽  
Todd Heallen ◽  
Ge Tao ◽  
James F Martin

Regeneration in mammalian hearts is limited due to the extremely low renewal rate of cardiomyocytes and their inability to reenter the cell cycle. In rodent hearts, endogenous regenerative capacity exists during development but is rapidly repressed after birth, at which time growth is by hypertrophy. During the developmental and neonatal periods, heart regeneration occurs through proliferation of pre-existing cardiomyocytes. Our approach of activating heart regeneration is to uncover the mechanisms responsible for repression of cardiomyocyte proliferation. The Hippo pathway controls heart size by repressing cardiomyocyte proliferation during development. By deleting Salv , a modulator of the Hippo pathway, we found that myocardial damage in postnatal and adult hearts was repaired both anatomically and functionally. This heart repair occurred primary through proliferation of preexisting cardiomyocytes. During repair, cardiomyocytes reenter the cell cycle; de novo DNA synthesis, karyokinesis, and cytokinesis all take place. The dystrophin glycoprotein complex (DGC) is essential for muscle maintenance by anchoring the cytoskeleton and extracellular matrix. Disruption of the DGC results in muscular dystrophies, including Duchenne muscular dystrophy, resulting in both skeletal and cardiac myopathies. Recently the DGC was shown to regulate cardiomyocyte proliferation and we found that the DGC and the Hippo pathway components directly interact. To address if the DGC and the Hippo pathway coordinately regulate cardiomyocyte proliferation, we conditionally deleted Salv in the mouse model of muscular dystrophy, the mdx line. We found that simultaneous disruption of both the DGC and Hippo pathway leads an increased de novo DNA synthesis and cytokinesis in cardiomyocytes after heart damage. Our findings provide new insights into the mechanisms leading to heart repair through proliferation of endogenous cardiomyocytes.


Cancers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 422 ◽  
Author(s):  
Liqing Wu ◽  
Xiaolong Yang

Breast cancer (BC) is one of the most prominent diseases in the world, and the treatments for BC have many limitations, such as resistance and a lack of reliable biomarkers. Currently the Hippo pathway is emerging as a tumor suppressor pathway with its four core components that regulate downstream transcriptional targets. In this review, we introduce the present targeted therapies of BC, and then discuss the roles of the Hippo pathway in BC. Finally, we summarize the evidence of the small molecule inhibitors that target the Hippo pathway, and then discuss the possibilities and future direction of the Hippo-targeted drugs for BC therapy.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Yuka Morikawa ◽  
James F Martin

Regeneration of the mammalian heart is limited in adults. In rodents, endogenous regenerative capacity exists during development and in neonate but is rapidly repressed after birth. We are elucidating the mechanisms responsible for regenerative repression and applying this knowledge to reactivate cardiac regeneration in adult hearts. We have previously shown that the Hippo pathway is responsive for regenerative repression, however, the molecular and cellular mechanism responsible remain unclear. The Hippo pathway controls heart size by repressing myocardial cell proliferation during development. By deleting Salv, a modulator of Hippo pathway, we found myocardial damage in the postnatal and adult heart was repaired anatomically and functionally. This heart repair occurred primarily through proliferation of preexisting cardiomyocyte. We observed that cardiomyocytes in border the zone protrude and fill the damage area during Hippo-mediated cardiac regeneration and thus preventing formation of fibrotic scars. The molecular analysis identified components of dystrophin glycoprotein complex (DGC) as downstream targets of Hippo pathway. The DGC anchors the cytoskeleton and extracellular matrix and is involved in cell migration. The studies using the muscular dystrophy mouse model, mdx, reveals that DGC is required for endogenous cardiac regeneration and cardiomyocyte protrusion. Taken together, we show that cardiomyocyte protrusion is an essential process for cardiac regeneration and the Hippo pathway regulates it through regulating DGC. Our studies provide insights into the mechanisms leading to repair of damaged hearts from endogenous cardiomyocytes and novel information into DGC function.


2019 ◽  
Vol 116 (37) ◽  
pp. 18455-18465 ◽  
Author(s):  
Zhaoning Wang ◽  
Miao Cui ◽  
Akansha M. Shah ◽  
Wenduo Ye ◽  
Wei Tan ◽  
...  

The adult mammalian heart has limited capacity for regeneration following injury, whereas the neonatal heart can readily regenerate within a short period after birth. To uncover the molecular mechanisms underlying neonatal heart regeneration, we compared the transcriptomes and epigenomes of regenerative and nonregenerative mouse hearts over a 7-d time period following myocardial infarction injury. By integrating gene expression profiles with histone marks associated with active or repressed chromatin, we identified transcriptional programs underlying neonatal heart regeneration, and the blockade to regeneration in later life. Our results reveal a unique immune response in regenerative hearts and a retained embryonic cardiogenic gene program that is active during neonatal heart regeneration. Among the unique immune factors and embryonic genes associated with cardiac regeneration, we identified Ccl24, which encodes a cytokine, and Igf2bp3, which encodes an RNA-binding protein, as previously unrecognized regulators of cardiomyocyte proliferation. Our data provide insights into the molecular basis of neonatal heart regeneration and identify genes that can be modulated to promote heart regeneration.


2013 ◽  
Vol 58 ◽  
pp. S14-S15
Author(s):  
G. Loforese ◽  
N. Lugli ◽  
K. Breu ◽  
A. Keogh ◽  
D. Candinas ◽  
...  

2015 ◽  
Vol 309 (8) ◽  
pp. H1237-H1250 ◽  
Author(s):  
Marina Leone ◽  
Ajit Magadum ◽  
Felix B. Engel

The newt and the zebrafish have the ability to regenerate many of their tissues and organs including the heart. Thus, a major goal in experimental medicine is to elucidate the molecular mechanisms underlying the regenerative capacity of these species. A wide variety of experiments have demonstrated that naturally occurring heart regeneration relies on cardiomyocyte proliferation. Thus, major efforts have been invested to induce proliferation of mammalian cardiomyocytes in order to improve cardiac function after injury or to protect the heart from further functional deterioration. In this review, we describe and analyze methods currently used to evaluate cardiomyocyte proliferation. In addition, we summarize the literature on naturally occurring heart regeneration. Our analysis highlights that newt and zebrafish heart regeneration relies on factors that are also utilized in cardiomyocyte proliferation during mammalian fetal development. Most of these factors have, however, failed to induce adult mammalian cardiomyocyte proliferation. Finally, our analysis of mammalian neonatal heart regeneration indicates experiments that could resolve conflicting results in the literature, such as binucleation assays and clonal analysis. Collectively, cardiac regeneration based on cardiomyocyte proliferation is a promising approach for improving adult human cardiac function after injury, but it is important to elucidate the mechanisms arresting mammalian cardiomyocyte proliferation after birth and to utilize better assays to determine formation of new muscle mass.


2020 ◽  
Vol 26 (9) ◽  
pp. 653-664
Author(s):  
Challis Karasek ◽  
Mohamed Ashry ◽  
Chad S Driscoll ◽  
Jason G Knott

Abstract In mammals, the first cell-fate decision occurs during preimplantation embryo development when the inner cell mass (ICM) and trophectoderm (TE) lineages are established. The ICM develops into the embryo proper, while the TE lineage forms the placenta. The underlying molecular mechanisms that govern lineage formation involve cell-to-cell interactions, cell polarization, cell signaling and transcriptional regulation. In this review, we will discuss the current understanding regarding the cellular and molecular events that regulate lineage formation in mouse preimplantation embryos with an emphasis on cell polarity and the Hippo signaling pathway. Moreover, we will provide an overview on some of the molecular tools that are used to manipulate the Hippo pathway and study cell-fate decisions in early embryos. Lastly, we will provide exciting future perspectives on transcriptional regulatory mechanisms that modulate the activity of the Hippo pathway in preimplantation embryos to ensure robust lineage segregation.


Cancers ◽  
2018 ◽  
Vol 10 (2) ◽  
pp. 45 ◽  
Author(s):  
Sayan Chakraborty ◽  
Wanjin Hong

In addition to the structural and scaffolding role, the extracellular matrix (ECM) is emerging as a hub for biomechanical signal transduction that is frequently relayed to intracellular sensors to regulate diverse cellular processes. At a macroscopic scale, matrix rigidity confers long-ranging effects contributing towards tissue fibrosis and cancer. The transcriptional co-activators YAP/TAZ, better known as the converging effectors of the Hippo pathway, are widely recognized for their new role as nuclear mechanosensors during organ homeostasis and cancer. Still, how YAP/TAZ senses these “stiffness cues” from the ECM remains enigmatic. Here, we highlight the recent perspectives on the role of agrin in mechanosignaling from the ECM via antagonizing the Hippo pathway to activate YAP/TAZ in the contexts of cancer, neuromuscular junctions, and cardiac regeneration.


2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Sandra Muñoz-Galván ◽  
Blanca Felipe-Abrio ◽  
Eva M. Verdugo-Sivianes ◽  
Marco Perez ◽  
Manuel P. Jiménez-García ◽  
...  

Abstract Background Ovarian cancer is one of the most common and malignant cancers, partly due to its late diagnosis and high recurrence. Chemotherapy resistance has been linked to poor prognosis and is believed to be linked to the cancer stem cell (CSC) pool. Therefore, elucidating the molecular mechanisms mediating therapy resistance is essential to finding new targets for therapy-resistant tumors. Methods shRNA depletion of MYPT1 in ovarian cancer cell lines, miRNA overexpression, RT-qPCR analysis, patient tumor samples, cell line- and tumorsphere-derived xenografts, in vitro and in vivo treatments, analysis of data from ovarian tumors in public transcriptomic patient databases and in-house patient cohorts. Results We show that MYPT1 (PPP1R12A), encoding myosin phosphatase target subunit 1, is downregulated in ovarian tumors, leading to reduced survival and increased tumorigenesis, as well as resistance to platinum-based therapy. Similarly, overexpression of miR-30b targeting MYPT1 results in enhanced CSC-like properties in ovarian tumor cells and is connected to the activation of the Hippo pathway. Inhibition of the Hippo pathway transcriptional co-activator YAP suppresses the resistance to platinum-based therapy induced by either low MYPT1 expression or miR-30b overexpression, both in vitro and in vivo. Conclusions Our work provides a functional link between the resistance to chemotherapy in ovarian tumors and the increase in the CSC pool that results from the activation of the Hippo pathway target genes upon MYPT1 downregulation. Combination therapy with cisplatin and YAP inhibitors suppresses MYPT1-induced resistance, demonstrating the possibility of using this treatment in patients with low MYPT1 expression, who are likely to be resistant to platinum-based therapy.


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