Plk1 regulates contraction of postmitotic smooth muscle cells and is required for vascular homeostasis

Polo-like kinase 1 (PLK1), an essential regulator of cell division, is currently undergoing clinical evaluation as a target for cancer therapy. We report an unexpected function of Plk1 in sustaining cardiovascular homeostasis. Plk1 haploinsufficiency in mice did not induce obvious cell proliferation defects but did result in arterial structural alterations, which frequently led to aortic rupture and death. Specific ablation of Plk1 in vascular smooth muscle cells (VSMCs) led to reduced arterial elasticity, hypotension, and an impaired arterial response to angiotensin II in vivo. Mechanistically, we found that Plk1 regulated angiotensin II-dependent activation of RhoA and actomyosin dynamics in VSMCs in a mitosis-independent manner. This regulation depended on Plk1 kinase activity, and the administration of small-molecule Plk1 inhibitors to angiotensin II-treated mice led to reduced arterial fitness and an elevated risk of aneurysm and aortic rupture. We thus conclude that a partial reduction of Plk1 activity that does not block cell division can nevertheless impair aortic homeostasis. Our findings have potentially important implications for current approaches aimed at PLK1 inhibition for cancer therapy.This work-was supported by the Marie Curie activities of the European Commission (Oncotrain program; fellowship to P.W), the Spanish Ministry of Economy and Competitiveness (MINECO; fellowship to A.G.-L.), the CENIT AMIT Project "Advanced Molecular Imaging Technologies" (TEC2008-06715-C02-1, RD07/0014/2009 to F.M.), the Red de investigacion Cardiovascular (RIC), cofunded by FEDER (grant RD12/004240022 to J.M.R.; grant RD12/0042/0056 to L.J.J.-B), Fundacio La Marato TV3 (grant 20151331 to J.M.R.), the Castilla-Leon Autonomous Government (BIO/SA01/15, CS049U16 to X.R.B.), the Solorzano and Ramon Areces Foundations (to X.R.B.), MINECO (grants RD12/0036/0002 and SAF2015-64556-R to X.R.B.; SAF2015-63633-R to J.M.R.; and SAF2015-69920-R to M.M.), Consolider-Ingenio 2010 Programme (grant SAF2014-57791-REDC to M.M.), Red Tematica CellSYS (grant BFU2014-52125-REDT to M.M.), Comunidad de Madrid (OncoCycle Programme; grant S2010/BMD-2470 to M.M.), Worldwide Cancer Research (grants 14-1248 to X.R.B., and 15-0278 to M.M.) and the MitoSys project (European Union Seventh Framework Programme; grant HEALTH-F5-2010-241548 to M.M.). CNIC is supported by MINECO and the Pro-CNIC Foundation. CNIO and CNIC are Severo Ochoa Centers of Excellence (MINECO awards SEV-2015-0510 and SEV-2015-0505, respectively).S

In COVID-19 Health Messaging, Loss Framing Increases Anxiety with Little-to-No Concomitant Benefits: Experimental Evidence from 84 Countries

The COVID-19 pandemic (and its aftermath) highlights a critical need to communicate health information effectively to the global public. Given that subtle differences in information framing can have meaningful effects on behavior, behavioral science research highlights a pressing question: Is it more effective to frame COVID-19 health messages in terms of potential losses (e.g., "If you do not practice these steps, you can endanger yourself and others") or potential gains (e.g., "If you practice these steps, you can protect yourself and others")? Collecting data in 48 languages from 15,929 participants in 84 countries, we experimentally tested the effects of message framing on COVID-19-related judgments, intentions, and feelings. Loss- (vs. gain-) framed messages increased self-reported anxiety among participants cross-nationally with little-to-no impact on policy attitudes, behavioral intentions, or information seeking relevant to pandemic risks. These results were consistent across 84 countries, three variations of the message framing wording, and 560 data processing and analytic choices. Thus, results provide an empirical answer to a global communication question and highlight the emotional toll of loss-framed messages. Critically, this work demonstrates the importance of considering unintended affective consequences when evaluating nudge-style interventions

A global experiment on motivating social distancing during the COVID-19 pandemic

Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

A global experiment on motivating social distancing during the COVID-19 pandemic

Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e. a controlling message) compared to no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly-internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared to the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly-internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing: Controlled motivation was associated with more defiance and less long-term behavioral intentions to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

Modeling plk1 function in the mouse

Tesis doctoral inédita realizada en la Universidad Autónoma de Madrid, Facultad de Medicina. Departamento de Bioquímica y Centro Nacional de Investigaciones Oncológicas. Fecha de lectura: 28 de Junio de 2010

Activation of the endomitotic spindle assembly checkpoint and thrombocytopenia in Plk1-deficient mice.

Polyploidization in megakaryocytes is achieved by endomitosis, a specialized cell cycle in which DNA replication is followed by aberrant mitosis. Typical mitotic regulators such as Aurora kinases or Cdk1 are dispensable for megakaryocyte maturation, and inhibition of mitotic kinases may in fact promote megakaryocyte maturation. However, we show here that Polo-like kinase 1 (Plk1) is required for endomitosis, and ablation of the Plk1 gene in megakaryocytes results in defective polyploidization accompanied by mitotic arrest and cell death. Lack of Plk1 results in defective centrosome maturation and aberrant spindle pole formation, thus impairing the formation of multiple poles typically found in megakaryocytes. In these conditions, megakaryocytes arrest for a long time in mitosis and frequently die. Mitotic arrest in wild-type megakaryocytes treated with Plk1 inhibitors or Plk1-null cells is triggered by the spindle assembly checkpoint (SAC), and can be rescued in the presence of SAC inhibitors. These data suggest that, despite the dispensability of proper chromosome segregation in megakaryocytes, an endomitotic SAC is activated in these cells upon Plk1 inhibition. SAC activation results in defective maturation of megakaryocytes and cell death, thus raising a note of caution in the use of Plk1 inhibitors in therapeutic strategies based on polyploidization regulators.This work was supported by a fellowship from the Foundation La Caixa (M.T.), and the Cell Division and Cancer group of the CNIO was funded by the Ministry of Economy and Competitiveness (SAF2012-38215), Consolider-Ingenio 2010 Programme (SAF2014-57791-REDC), Red Tematica CellSYS (BFU2014-52125-REDT), Comunidad de Madrid (OncoCycle Programme, S2010/BMD-2470), Worldwide Cancer Research (WCR #15-0278), and the MitoSys project (HEALTH-F5-2010-241548, European Union Seventh Framework Programme).S

Genetic depletion of Polo-like kinase 1 leads to embryonic lethality due to mitotic aberrancies

Polo-like kinase 1 (PLK1) is a serine/threonine kinase that plays multiple and essential roles during the cell division cycle. Its inhibition in cultured cells leads to severe mitotic aberrancies and cell death. Whereas previous reports suggested that Plk1 depletion inmice leads to a non-mitotic arrest in early embryos, we show here that the bi-allelic Plk1 depletion in mice certainly results in embryonic lethality due to extensive mitotic aberrations at the morula stage, including multi-and mono-polar spindles, impaired chromosome segregation and cytokinesis failure. In addition, the conditional depletion of Plk1 during mid-gestation leads also to severe mitotic aberrancies. Our data also confirms that Plk1 is completely dispensable for mitotic entry in vivo. On the other hand, Plk1 haploinsufficient mice are viable, and Plk1-heterozygous fibroblasts do not harbor any cell cycle alterations. Plk1 is overexpressed in many human tumors, suggesting a therapeutic benefit of inhibiting Plk1, and specific small-molecule inhibitors for this kinase are now being evaluated in clinical trials. Therefore, the different Plk1 mouse models here presented are a valuable tool to reexamine the relevance of the mitotic kinase Plk1 during mammalian development and animal physiology

Activation of the endomitotic spindle assembly checkpoint and thrombocytopenia in Plk1-deficient mice

Polyploidization in megakaryocytes is achieved by endomitosis, a specialized cell cycle in which DNA replication is followed by aberrant mitosis. Typical mitotic regulators such as Aurora kinases or Cdk1 are dispensable for megakaryocyte maturation, and inhibition of mitotic kinases may in fact promote megakaryocyte maturation. However, we show here that Polo-like kinase 1 (Plk1) is required for endomitosis, and ablation of the Plk1 gene in megakaryocytes results in defective polyploidization accompanied by mitotic arrest and cell death. Lack of Plk1 results in defective centrosome maturation and aberrant spindle pole formation, thus impairing the formation of multiple poles typically found in megakaryocytes. In these conditions, megakaryocytes arrest for a long time in mitosis and frequently die. Mitotic arrest in wild-type megakaryocytes treated with Plk1 inhibitors or Plk1-null cells is triggered by the spindle assembly checkpoint (SAC), and can be rescued in the presence of SAC inhibitors. These data suggest that, despite the dispensability of proper chromosome segregation in megakaryocytes, an endomitotic SAC is activated in these cells upon Plk1 inhibition. SAC activation results in defective maturation of megakaryocytes and cell death, thus raising a note of caution in the use of Plk1 inhibitors in therapeutic strategies based on polyploidization regulators.Depto. de Bioquímica y Biología MolecularFac. de Ciencias BiológicasTRUEpu

Model construction and optimization workflow.

<p>The Prior Knowledge Network (PKN) is constructed after collecting relevant information from various sources, including network databases and literature. The PKN is translated into logical functions, describing the regulatory relations among gene products. The logical model is simulated under the preferred conditions, resulting in one or more steady states, where all logical rules are satisfied. The model goes then through an optimization procedure, where the goal is to fit the resulting steady states with available experimental data by altering regulatory rules. The optimization typically includes removing outdated / low confidence links, adjusting their representation and adding new regulatory rules. The process is iterated until the simulation fits the available data. The model can then be used as a predictive tool, by performing <i>in silico</i> perturbations. Validation of the predictions can lead to discovery of missing regulatory links that are then added to the PKN.</p