Chao L.H.,University of California at Berkeley |
Chao L.H.,Howard Hughes Medical Institute |
Stratton M.M.,University of California at Berkeley |
Stratton M.M.,Howard Hughes Medical Institute |
And 15 more authors.
Cell | Year: 2011
Calcium/calmodulin-dependent kinase II (CaMKII) forms a highly conserved dodecameric assembly that is sensitive to the frequency of calcium pulse trains. Neither the structure of the dodecameric assembly nor how it regulates CaMKII are known. We present the crystal structure of an autoinhibited full-length human CaMKII holoenzyme, revealing an unexpected compact arrangement of kinase domains docked against a central hub, with the calmodulin-binding sites completely inaccessible. We show that this compact docking is important for the autoinhibition of the kinase domains and for setting the calcium response of the holoenzyme. Comparison of CaMKII isoforms, which differ in the length of the linker between the kinase domain and the hub, demonstrates that these interactions can be strengthened or weakened by changes in linker length. This equilibrium between autoinhibited states provides a simple mechanism for tuning the calcium response without changes in either the hub or the kinase domains. PaperFlick: © 2011 Elsevier Inc.
Stratton M.M.,University of California at Berkeley |
Stratton M.M.,Howard Hughes Medical Institute |
Chao L.H.,University of California at Berkeley |
Chao L.H.,Howard Hughes Medical Institute |
And 5 more authors.
Current Opinion in Structural Biology | Year: 2013
Ca2+/calmodulin dependent protein kinase II (CaMKII) is a broadly distributed metazoan Ser/Thr protein kinase that is important in neuronal and cardiac signaling. CaMKII forms oligomeric assemblies, typically dodecameric, in which the calcium-responsive kinase domains are organized around a central hub. We review the results of crystallographic analyses of CaMKII, including the recently determined structure of a full-length and autoinhibited form of the holoenzyme. These structures, when combined with other data, allow informed speculation about how CaMKII escapes calcium-dependence when calcium spikes exceed threshold frequencies. © 2013 Elsevier Ltd.
Pellicena P.,Allosteros Therapeutics, Inc. |
Schulman H.,Allosteros Therapeutics, Inc.
Frontiers in Pharmacology | Year: 2014
The cardiac field has benefited from the availability of several CaMKII inhibitors serving as research tools to test putative CaMKII pathways associated with cardiovascular physiology and pathophysiology. Successful demonstrations of its critical pathophysiological roles have elevated CaMKII as a key target in heart failure, arrhythmia, and other forms of heart disease. This has caught the attention of the pharmaceutical industry, which is now racing to develop CaMKII inhibitors as safe and effective therapeutic agents. While the first generation of CaMKII inhibitor development is focused on blocking its activity based on ATP binding to its catalytic site, future inhibitors can also target sites affecting its regulation by Ca2+/CaM or translocation to some of its protein substrates. The recent availability of crystal structures of the kinase in the autoinhibited and activated state, and of the dodecameric holoenzyme, provides insights into the mechanism of action of existing inhibitors. It is also accelerating the design and development of better pharmacological inhibitors. This review examines the structure of the kinase and suggests possible sites for its inhibition. It also analyzes the uses and limitations of current research tools. Development of new inhibitors will enable preclinical proof of concept tests and clinical development of successful lead compounds, as well as improved research tools to more accurately examine and extend knowledge of the role of CaMKII in cardiac health and disease. © 2014 Pellicena and Schulman.
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 279.18K | Year: 2012
DESCRIPTION (provided by applicant): Osteosarcoma is the most common primary bone cancer in children and adolescents. A key feature of osteosarcoma is their inherent high growth rates and the increased vasculature to enable rapid growth. Recent data implicate Ca2+/CaM-dependent protein kinase II (CaMKII), a major mediator of Ca2+ signaling, in both the unregulated proliferation of osteosarcoma and in the angiogenesis that supports its growth. Hyperactivity of CaMKII is associated with cell proliferation and resistance to apoptosis, while inhibition of CaMKII suppresses growth of osteosarcoma in animals. We aim to focus medicinal chemistry and preclinical development to generate improved CaMKII inhibitors that incorporate an allosteric site interaction. Ourstrategy is to start with a potent lead ATP site inhibitor of the kinase and extend it to interact with the helical inhibitory domain of the kinase. Biochemical analysis of inhibitors will measure their interaction with the inactive and active conformations. Medicinal chemistry will be used to develop inhibitors that span the catalytic site with preferential binding to the inactive conformation that is characteristic of allosteric interactions. While our current lead compounds can be used to test efficacyin osteosarcoma, the allosteric inhibitors will be more broadly useful because of greater selectivity. The best inhibitor will be tested for efficacy for its cellular action followed by efficacy on human osteosarcoma xenografted in mice. This will providea clear path for a Phase II proposal to further improve its potency and other drug-like properties up to IND filing. CaMKII inhibitors may present a new paradigm in osteosarcoma-targeted agents that effectively treat the tumor by the dual mechanism of slowing its rapid growth and blocking its access to nutrients. PUBLIC HEALTH RELEVANCE: Osteosarcoma is the most common primary bone cancer in children and adolescents. A key feature of osteosarcomas is their inherent high growth rates and the increased vasculature to enable rapid growth. Recent data implicate Ca2+/CaM-dependent protein kinase II (CaMKII), a major mediator of Ca2+ signaling, in both the unregulated proliferation of osteosarcoma and in the increased blood vessel formation that upports its growth. We aim to modify an existing potent small molecule inhibitor of CaMKII to increase its selectivity, test it biochemically to ensure it has the desired mechanism of action, then test it on xenografted human osteosarcoma.
Allosteros Therapeutics, Inc. | Date: 2014-03-05
The present invention provides compounds useful as inhibitors of Ca^(2+)/calmodulin-dependent protein kinase (CaMKII), compositions thereof, and methods of using the same.
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 257.36K | Year: 2012
DESCRIPTION (provided by applicant): Ventricular arrhythmias have diverse and complex etiologies that include excessive stimulation of multiple neurohumoral pathological pathways, suggesting that no single upstream blocker will be sufficiently efficacious.Ca[2+]/calmodulin-dependent protein kinase II (CaMKII) is a common downstream mediator of these neurohumoral pathways and its hyperactivity contributes to the mechanisms of ventricular arrhythmia. We propose that the kinase is a novel therapeutic target,an idea supported by the demonstration that pharmacological and genetic reduction of CaMKII activity decreases arrhythmia in animal models and in human cardiomyocytes from patients with arrhythmia and elevated CaMKII. We have developed small molecule inhibitors of CaMKII and propose to increase potency and selectivity of the lead compound then test the best compounds for inhibition of arrhythmia in a robust mouse model. Guided by insights we developed from docking inhibitors to its active site in our new crystal structures we propose a set of compounds designed for lead optimization. Our goal is to improve potency 10-fold and reach IC50s below 15 nM. The preclinical proof-of concept study will test the in vivo efficacy of the top inhibitors using a calcineurin over expressing mouse model that is relevant to larger animal models, and likely to diseased human myocardium as well. The mice have severe heart failure and high levels of ambient arrhythmias resulting from increased CaMKII expression and our milestoneis to show efficacy with at least one CaMKII inhibitor. If successful we will be positioned to extend the preclinical development by optimizing the inhibitors for ADME/Tox and other drug-like properties, testing their efficacy in other animal models, andperform IND enabling studies for an IND application aimed at arrhythmia in heart failure. PUBLIC HEALTH RELEVANCE: Sudden cardiac death is a major public health problem, which is estimated to kill 500,000 Americans each year. Most sudden cardiacdeath is due to rapid ventricular arrhythmias and patients with heart failure are at highest risk. Evidence now supports that pharmacological targeting of intracellular signaling, in particular of Ca2+/calmodulin-dependent protein kinase II, a sensor of dysregulated calcium homeostasis, will inhibit arrhythmia in heart failure, and it is thus a novel target in arrhythmia. We propose to modify a small molecule inhibitor we developed for this protein kinase in ways that increase its potency, analyze the new inhibitors biochemically to ensure they have the desired properties, and then test for inhibition of arrhythmia in a mouse model as a proof-of-concept.
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 249.70K | Year: 2012
DESCRIPTION (provided by applicant): Stroke is a major public health problem, with a US mortality rate that ranks third behind other diseases involving the cardiovascular system and cancer. We propose to pursue neuroprotection in ischemic stroke by targeting a key regulator of Ca2+ homeostasis, Ca2+/CaM-dependent protein kinase II (CaMKII). Inhibition of CaMKII represents a novel paradigm in ischemic stroke-neuroprotection based on blocking the effects of CaMKII on Ca2+ overload as well as its more direct effect on mediators of neurotoxicity. Two developments provide us with the rationale and opportunity to test potent small molecule CaMKII inhibitors in ischemic stroke. First, hyperactivity of CaMKII has been shown to promote cell death in glutamate excitotoxicity while inhibitors of the kinase are neuroprotective in situ and in the middle cerebral artery occlusion (MCAO) model. Second we have taken the opportunity to restart a CaMKII inhibitor program initially advanced at a pharm and which we are now accelerating based on insights from the first crystal structures of the human enzyme. Our proposal is relatively straightforward, to increase CNS penetration of the potent inhibitors we developed and test the optimized lead compound in a permanent occlusion MCAO model. We have designed a number of modifications that increase lipophilicity of our compounds with the aim of increasing their CNS penetration. The compounds will be analyzed for kinase inhibition and selectivity in vitro, and for inhibition and protection from glutamate excitotoxicity in neuronal cultures. The inhibitor with the greatest potential for CNS penetration will be selected based on bidirectional permeability through MDR----MDCK monolayers and its brain/plasma distribution in vivo will be quantified. The lead CNS penetrating inhibitor will be tested in the rat permanent occlusion MCAO model. We will monitor the degree of CaMKII inhibition achieved in vivo using biomarkers of kinase activity and quantify the effect of the inhibitor on infarct size. A successfully proof----of----concept in ischemic stroke will position us for a Phase II SBIR proposal to optimize the drug----like properties and conduct IND enabling studies of the lead compound. PUBLIC HEALTH RELEVANCE: Stroke is a major public health problem with a US mortality rate that ranks third behind other diseases involving the cardiovascular system and cancer. Recent data implicate hyperactivity of Ca2+/CaM- dependent protein kinase II (CaMKII), a major mediator of Ca2+ signaling, inischemic damage. We aim to increase the brain penetration of our potent CaMKII inhibitors and test the optimized lead compound for efficacy in an animal model of human ischemic stroke.ischemic stroke.
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 212.92K | Year: 2011
DESCRIPTION (provided by applicant): Heart disease converts to the clinical syndrome of heart failure when the cardiac output is inadequate to meet metabolic requirements. Evidence now supports that pharmacological targeting of Ca2???? dependent protein kinase II (CaMKII), a sensor of dysregulated calcium homeostasis, will inhibit conversion of early stages of cellular pathophysiology to symptomatic heart failure and sudden death. Inhibition of the kinase with research inhibitors, or by genetic knock-out ofthe major cardiac isoform, blocks this chain of events in animal models. We propose a strategy to modify a small molecule inhibitor of CaMKII to increase its potency and selectivity, test it biochemically to ensure it has the desired mechanism of action,then test for inhibition of characterized markers of hypertrophy and for apoptosis in neonatal mouse cardiomyocytes. We start with an allosteric CaMKII inhibitor used to demonstrate its cardiovascular functions but has never been pharmacologically optimized and thus have low potency. Guided by our analysis of new crystal structures and structural insights we have developed from docking inhibitors to its active site we have designed a set of compounds that target a unique feature of the allosteric pocket inthe active site of CaMKII. Our overall goals for Phase I are to retain and improve the selectivity of the inhibitor while markedly increasing its potency, and to test the lead inhibitor compounds for efficacy then test for inhibition of characterized markers of hypertrophy and for apoptosis it in neonatal mouse cardiomyocytes PUBLIC HEALTH RELEVANCE: Heart failure is a global burden, with the lifetime risk in the developed world above 20% and a consuming focus for patients, clinicians, scientists, and policymakers. Heart disease converts to the clinical syndrome of heart failure when the cardiac output is inadequate to meet metabolic requirements. Evidence now supports that pharmacological targeting of intracellular signaling, in particular of Ca2????dependent protein kinase II, a sensor of dysregulated calcium homeostasis will inhibit conversion to symptomatic heart failure and sudden death. We propose a strategy to modify a small molecule inhibitor of this protein kinase in ways that increase its potency, analyze it biochemically to ensure it has the desired mechanism of action, then test for inhibition of characterized markers of hypertrophy and for apoptosis it in neonatal mouse cardiomyocytes.
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 249.17K | Year: 2011
DESCRIPTION (provided by applicant): Asthma is a major public health problem affecting 25 million American adults and children in the US and over 300 million people globally. It is characterized by reversible airflow obstruction due to bronchial smooth muscle contraction and a diseased epithelial cell phenotype of airway hyper-reactivity (AHR) to environmental stimuli, increase in goblet cell, and increased luminal mucous secretion. The allergic response is associated with an increase in reactive oxygen species (ROS) in bronchial epithelium that precedes and promotes epithelial cell dysfunction. There is an unmet need for disease modifying therapy that reduces reliance on glucocorticoids, potentially by targeting pathways of oxidative damage. Our recent studies position Ca2???? (CaM)-dependent protein kinase II (CaMKII) as a key sensor, amplifier, and mediator of pathological ROS responses in asthma. We aim to optimize a small molecule inhibitor of CaMKII based on new insights from CaMKII crystal structures and thereby improve its drug-like properties. We will increase its potency and then test our lead compound in a validated mouse model of allergic asthma. Our overall goals for Phase I are to perform sufficient lead optimization to conduct a pre-clinical proof-of-concept that CaMKII inhibition suppresses AHR and other asthma phenotypes. We have designed inhibitors based on new crystal structure of the enzyme that together with prior SAR suggests how it binds the kinase and identifies nearby residues that newcompounds can interact with to produce more potent and more selective inhibitors. Optimized lead inhibitors will then be tested for efficacy in the ovalbumin mouse model of allergic asthma, monitoring its efficacy in AHR, goblet cell metaplasia, and mucoussecretion. This previously unrecognized disease pathway offers a novel and innovative therapeutic opportunity for asthma. Our overall Phase I aim is to test an improved lead compound in the ovalbumin model, that if successful would justify a Phase II proposal to optimize drug-like properties of the lead compound and perform the ADME/Tox and other studies necessary to reach IND. PUBLIC HEALTH RELEVANCE: Asthma is a major public health problem affecting 25 million American adults and children in theUS and over 300 million people globally. The reduced lung function and disease phenotype of airway hyper-reactivity to environmental stimuli and increased luminal mucous secretion is preceded by oxidation and inflammation of bronchial epithelium. Our recent studies implicate Ca2????dependent protein kinase II (CaMKII) as a key sensor, amplifier, and mediator of pathological oxidation and inflammation in asthma. We aim to optimize a small molecule inhibitor of CaMKII based on new insights of its structure tofill an unmet need for disease modifying therapy that reduces reliance on glucocorticoids, potentially by targeting pathways of oxidative damage.
Agency: Department of Health and Human Services | Branch: National Institutes of Health | Program: SBIR | Phase: Phase I | Award Amount: 249.03K | Year: 2016
DESCRIPTION provided by applicant Atrial fibrillation AF is the most common cardiac arrhythmia a condition that predisposes individuals to heart failure and stroke and is a major contributor to cardiovascular mortality There is an unmet need to treat AF and the underlying electrical and structural changes in heart There is a long unsuccessful history of ion channel blockers in AF invariably they are proarrhythmic We have identified a new target for atrial fibrillation Ca CaM dependent protein kinase II CaMKII whose hyperactivity is pro arrhythmic via multiple pathways and systems implicated in the genesis of AF and ventricular arrhythmia VA Targeting CaMKII is an innovative new paradigm treating AF while also being anti arrhythmic in ventricle In humans and mice CaMKII made hyperactivity by autophosphorylation and oxidation elicits a diastolic Ca andapos leakandapos from the sarcoplasmic reticulum via the ryanodine receptor RyR hyperphosphorylation leading to AF Atrial tissue from patients with AF is marked by elevated CaMKII activity while CaMKII inhibition prevents aberrant RyR Ca release Furthermore inhibition of the kinase with our lead compound or genetic ablation of CaMKII or its phosphorylation site on RyR blocks this chain of events and reduces the frequency of AF in mice We aim to modify our potent and selective lead compound to i reduce its rapid liver microsomal metabolism in rodents which will facilitate preclinical development toward IND and ii limit any central nervous system CNS penetration to mitigate concerns regarding CaMKII inhibition in brain Following lead optimization we will test efficacy in an established in vivo mouse model of induced AF and in an isolated rabbit heart model The Ryr R Q AF mouse model exhibits a Ca leak and susceptibility to ectopic activity reentry and AF triggered by atrial pacing Importantly these models share mechanisms with post op AF a significant inpatient indication and an achievable entry point for Allosteros Therapeutics in cardiovascular therapeutics The study will also include assay of biomarkers to assess in vivo inhibition of CaMKII and reduction in site specific phosphorylation of its targets RyR and phospholamban The Phase I work will position us for lead selection and IND enabling studies and enable us to reach metabolic and drug disposition milestones sought by investors and pharma who now recognize that CaMKII is a consensus target in AF and VA PUBLIC HEALTH RELEVANCE Atrial fibrillation is the most common cardiac arrhythmia a condition that predisposes individuals to heart failure and stroke and is a major contributor to cardiovascular mortality There is an unmet need to treat atrial fibrillation and the underlying electrical and structural changes in heart We have identified a new target Ca CaM dependent protein kinase CaMKII whose hyperactivity is associated with atrial fibrillation in human patients and in animal models We have a small molecule inhibitor of CaMKII that markedly reduces the frequency of atrial fibrillation in animal models We aim to optimize it so that it acts in the periphery and not the brain and that it is not quickly metabolized We will the test the optimized inhibitors in animal models of atrial fibrillation