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Calcium/calmodulin-dependent protein kinase II (CaMKII) is a multifunctional serine/threonine protein kinase that transmits calcium signals in various cellular processes. CaMKII is activated by calcium-bound calmodulin (Ca 2+ /CaM) through a direct binding mechanism involving a regulatory C-terminal α-helix in CaMKII. The Ca 2+ /CaM binding triggers transphosphorylation of critical threonine residues proximal to the CaM-binding site leading to the autoactivated state of CaMKII. The demonstration of its critical roles in pathophysiological processes has elevated CaMKII to a key target in the management of numerous diseases. The molecule KN-93 is the most widely used inhibitor for studying the cellular and in vivo functions of CaMKII. It is widely believed that KN-93 binds directly to CaMKII, thus preventing kinase activation by competing with Ca 2+ /CaM. Herein, we employed surface plasmon resonance, NMR, and isothermal titration calorimetry to characterize this presumed interaction. Our results revealed that KN-93 binds directly to Ca 2+ /CaM and not to CaMKII. This binding would disrupt the ability of Ca 2+ /CaM to interact with CaMKII, effectively inhibiting CaMKII activation. Our findings also indicated that KN-93 can specifically compete with a CaMKIIδ-derived peptide for binding to Ca 2+ /CaM. As indicated by the surface plasmon resonance and isothermal titration calorimetry data, apparently at least two KN-93 molecules can bind to Ca 2+ /CaM. Our findings provide new insight into how in vitro and in vivo data obtained with KN-93 should be interpreted. They further suggest that other Ca 2+ /CaM-dependent, non-CaMKII activities should be considered in KN-93-based mechanism-of-action studies and drug discovery efforts., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Rationale: Ca/calmodulin-dependent protein kinase II (CaMKII) was shown to increase diastolic sarcoplasmic reticulum (SR) Ca leak, which can result in delayed afterdepolarizations and triggered arrhythmias. Since increased CaMKII expression and activity has been mechanistically linked to arrhythmias in human heart failure (HF) and atrial fibrillation (AF), specific strategies aimed at CaMKII inhibition may have therapeutic potential., Objective: We tested the antiarrhythmic and inotropic effects of a novel selective and ATP-competitive CaMKII inhibitor (GS-680)., Methods and Results: Trabeculae were isolated from right atrial appendage biopsies of patients undergoing cardiac surgery. Premature atrial contractions (PACs) were induced by stimulation with isoproterenol (ISO, 100 nM) at increased [Ca] o (3.5 mM). Interestingly, compared to vehicle, PACs were significantly inhibited by exposure to GS-680 (at 100 and 300 nM). GS-680 also significantly decreased early and delayed afterdepolarizations in isolated human atrial myocytes. Moreover, GS-680 (at 100 or 300 nM) significantly inhibited diastolic SR Ca leak, measured as frequency of spontaneous SR Ca release events (Ca sparks) in isolated human atrial myocytes (Fluo-4 loaded) similar to the well-established peptide CaMKII inhibitor AIP. In accordance, GS-680 significantly reduced CaMKII autophosphorylation (Western blot) but enhanced developed tension after 10 or 30 s pause of electrical stimulation (post-rest behavior). Surprisingly, we found a strong negative inotropic effect of GS-680 in atrial trabeculae at 1 Hz stimulation rate, which was not observed at 4 Hz and abolished by beta-adrenergic stimulation. In contrast, GS-680 did not impair systolic force of isolated ventricular trabeculae from explanted hearts of heart transplant recipients at 1 Hz, blunted the negative force-frequency relationship (1-3 Hz) and significantly increased the Ca transient amplitude., Conclusion: The novel ATP-competitive and selective CaMKII inhibitor GS-680 inhibits pro-arrhythmic activity in human atrium and improves contractility in failing human ventricle, which may have therapeutic implications., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

We hereby disclose the discovery of inhibitors of CaMKII (7h and 7i) that are highly potent in rat ventricular myocytes, selective against hERG and other off-target kinases, while possessing good CaMKII tissue isoform selectivity (cardiac γ/δ vs. neuronal α/β). In vitro and in vivo ADME/PK studies demonstrated the suitability of these CaMKII inhibitors for PO (7h rat F = 73%) and IV pharmacological studies., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Late sodium current (late I Na ) is enhanced during ischemia by reactive oxygen species (ROS) modifying the Na v 1.5 channel, resulting in incomplete inactivation. Compound 4 (GS-6615, eleclazine) a novel, potent, and selective inhibitor of late I Na , is currently in clinical development for treatment of long QT-3 syndrome (LQT-3), hypertrophic cardiomyopathy (HCM), and ventricular tachycardia-ventricular fibrillation (VT-VF). We will describe structure-activity relationship (SAR) leading to the discovery of 4 that is vastly improved from the first generation late I Na inhibitor 1 (ranolazine). Compound 4 was 42 times more potent than 1 in reducing ischemic burden in vivo (S-T segment elevation, 15 min left anteriorior descending, LAD, occlusion in rabbits) with EC 50 values of 190 and 8000 nM, respectively. Compound 4 represents a new class of potent late I Na inhibitors that will be useful in delineating the role of inhibitors of this current in the treatment of patients.

We started with a medium throughput screen of heterocyclic compounds without basic amine groups to avoid hERG and β-blocker activity and identified [1,2,4]triazolo[4,3-a]pyridine as an early lead. Optimization of substituents for Late INa current inhibition and lack of Peak INa inhibition led to the discovery of 4h (GS-458967) with improved anti-arrhythmic activity relative to ranolazine. Unfortunately, 4h demonstrated use dependent block across the sodium isoforms including the central and peripheral nervous system isoforms that is consistent with its low therapeutic index (approximately 5-fold in rat, 3-fold in dog). Compound 4h represents our initial foray into a 2nd generation Late INa inhibitor program and is an important proof-of-concept compound. We will provide additional reports on addressing the CNS challenge in a follow-up communication., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Previously we disclosed the discovery of potent Late INa current inhibitor 2 (GS-458967, IC50 of 333nM) that has a good separation of late versus peak Nav1.5 current, but did not have a favorable CNS safety window due to high brain penetration (3-fold higher partitioning into brain vs plasma) coupled with potent inhibition of brain sodium channel isoforms (Nav1.1, 1.2, 1.3). We increased the polar surface area from 50 to 84Å(2) by adding a carbonyl to the core and an oxadiazole ring resulting in 3 GS-462808 that had lower brain penetration and serendipitously lower activity at the brain isoforms. Compound 3 has an improved CNS window (>20 rat and dog) relative to 2, and improved anti-ischemic potency relative to ranolazine. The development of 3 was not pursued due to liver lesions in 7day rat toxicology studies., (Copyright © 2016. Published by Elsevier Ltd.)

Two structurally distinct series of SCD (Delta9 desaturase) inhibitors (1 and 2) have been previously reported by our group. In the present work, we merged the structural features of the two series. This led to the discovery of compound 5b (CVT-12,012) which is highly potent in a human cell-based (HEPG2) SCD assay (IC(50)=6nM). This compound has 78% oral bioavailability in rats and is preferentially distributed into liver (76 times vs plasma) with relatively low brain penetration. In a five-day study (sucrose fed rats) compound 5b significantly reduced SCD activity in a dose-dependent manner as determined by GC analysis of fatty acid composition in plasma and liver, and significantly reduced liver triglycerides versus the control group ( approximately 50%).

We discovered a structurally novel SCD (Delta9 desaturase) inhibitor 4a (CVT-11,563) that has 119 nM potency in a human cell-based (HEPG2) SCD assay and selectivity against Delta5 and Delta6 desaturases. This compound has 90% oral bioavailability (rat) and excellent plasma exposure (dAUC 935 ng h/mL). Additionally, 4a shows moderately selective liver distribution (three times vs plasma and adipose tissue) and relatively low brain penetration. In a five-day study (high sucrose diet, rat) compound 4a significantly reduced SCD activity as determined by GC analysis of fatty acid composition in plasma and liver. We describe the discovery of 4a from HTS hit 1 followed by scaffold replacement and SAR studies focused on DMPK properties.

We identified a series of structurally novel SCD (Delta9 desaturase) inhibitors via high-throughput screening and follow-up SAR studies. Modification of the central bicyclic scaffold has proven key to our potency optimization effort. The most potent analog (8g) had IC(50) value of 50 pM in a HEPG2 SCD assay and has been shown to be metabolically stable and selective against Delta5 and Delta6 desaturases.

New inhibitors of palmitoyl-CoA oxidation are based on the introduction of nitrogen heterocycles in the 'Western Portion' of the molecule. SAR studies led to the discovery of CVT-4325 (shown), a potent FOXi (IC50=380 nM rat mitochondria) with favorable PK properties (F=93%, t(1/2)=13.6h, dog).

New inhibitors of palmitoylCoA oxidation were synthesized based on a structurally novel lead, CVT-3501 (1). Investigation of structure-activity relationships was conducted with respect to potency of inhibition of cardiac mitochondrial palmitoylCoA oxidation and metabolic stability. Potent and metabolically stable analogues 33, 42, and 43 were evaluated in vitro for cytochrome P450 inhibition and potentially adverse electrophysiological effects. Compound 33 was also found to have favorable pharmacokinetic properties in rat.

[structure: see text] The stereoselectivity of N-methylputrescine (3) oxidation to pyrrolinium ion 4 in Erythroxylum coca during cocaine (1) biosynthesis was studied. The remote isotope method was used to advantage. Each enantiomer of 4-monodeuterated N-methylputrescine served as a precursor for plant feeding. To facilitate mass-spectrometric analysis of products, a 2H3 13C-methyl group was also incorporated into the 4-deuterio-N-methylputrescines. Oxidative deamination of N-methylputrescine was found to be stereoselective; the pro-S hydrogen atom is removed with 6-10:1 selectivity.

The aim of this study were to estimate associations of sarcopenic status with depressive symptoms. We used mixed-effects linear model to estimate longitudinal association between sarcopenic status and rate of change in 10-item Center for Epidemiologic Studies Depression (CES-D) scores, and used Cox regression model to estimate the association between sarcopenic status and incident depression (CES-D ≥ 10). Stratification analyses were performed when the interactions between sarcopenic status and covariates were significant. A total of 6522 participants were ultimately included. After adjusting for covariates, participants with possible sarcopenia (β = 0.117; 95% CI 0.067 to 0.166; P < 0.001) and sarcopenia (β: 0.093; 95% CI 0.027–0.159; P < 0.001) had a faster increase in CES-D scores compared with normal individuals. Interactions between smoking and sarcopenic status were significant (Pinteraction < 0.05). We found significantly positive associations of sarcopenic status with CES-D scores in nonsmokers, but not in current and past smokers. Besides, compared with normal participants, those with possible sarcopenia (HR 1.15; 95% CI 1.05 to 1.27) and sarcopenia (HR 1.28; 95% CI 1.12 to 1.46) (Ptrend < 0.001) had elevated risks of incident depression. Sarcopenia is associated with a faster increase in CES-D scores and increased risks of depression among Chinese middle-aged and older adults. Stronger associations between sarcopenia and trajectory of CES-D scores were found in nonsmokers than in smokers. [ABSTRACT FROM AUTHOR]

Early brain injury (EBI) is the leading cause of poor prognosis for patients suffering from subarachnoid hemorrhage (SAH), particularly learning and memory deficits in the repair phase. A recent report has involved calcium/calmodulin-dependent protein kinase II (CaMKII) in the pathophysiological process underlying SAH-induced EBI. Alpha-asarone (ASA), a major compound isolated from the Chinese medicinal herb Acorus tatarinowii Schott, was proven to reduce secondary brain injury by decreasing CaMKII over-phosphorylation in rats' model of intracerebral hemorrhage in our previous report. However, the effect of ASA on SAH remains unclear, and the role of CaMKII in both acute and recovery stages of SAH needs further investigation. In this work, we first established a classic SAH rat model by endovascular perforation and intraperitoneally administrated different ASA doses (10, 20, and 40 mg/kg) 2 h after successful modeling. Then, the short- and long-term neurobehavioral performances were blindly evaluated to confirm ASA's efficacy against SAH. Subsequently, we explored ASA's therapeutic mechanism in both acute and recovery stages using histopathological examination, TUNEL staining, flow cytometry, Western-blot, double-immunofluorescence staining, and transmission electron microscopy (TEM) observation. Finally, KN93, a selective CaMKII inhibitor, was applied in oxyhemoglobin-damaged HT22 cells to explore the role of CaMKII in ASA's neuroprotective effect. The results demonstrated that ASA alleviated short- and long-term neurological dysfunction, reduced mortality and seizure rate within 24 h, and prolonged 14-day survival in SAH rats. Histopathological examination showed a reduction of neuronal damage and a restoration of the hippocampal structure after ASA treatment in both acute and recovery phases of SAH. In the acute stage, the Western-blot and flow cytometer analyses showed that ASA restored E/I balance, reduced calcium overload and CaMKII phosphorylation, and inhibited mitochondrion-involved apoptosis, thus preventing neuronal damage and apoptosis underlying EBI post-SAH. In the recovery stage, the TEM observation, double-immunofluorescence staining, and Western-blot analyses indicated that ASA increased the numbers of synapses and enhanced synaptic plasticity in the ipsilateral hippocampi, probably by promoting NR2B/CaMKII interaction and activating subsequent CREB/BDNF/TrkB signaling pathways. Furthermore, KN93 notably reversed ASA's neuroprotective effect on oxyhemoglobin-damaged HT22 cells, confirming CaMKII a potential target for ASA's efficacy against SAH. Our study confirmed for the first time that ASA ameliorated the SAH rats' neurobehavioral deterioration, possibly via modulating CaMKII-involved pathways. These findings provided a promising candidate for the clinical treatment of SAH and shed light on future drug discovery against SAH. [ABSTRACT FROM AUTHOR]

Short-chain fatty acids (SCFAs) are essential molecules produced by gut bacteria that fuel intestinal cells and may also influence overall health. An imbalance of SCFAs can result in various acute and chronic diseases, including diabetes, obesity and colorectal cancer (CRC). This review delves into the multifaceted roles of SCFAs, including a brief discussion on their source and various gut-residing bacteria. Primary techniques used for detection of SCFAs, including gas chromatography, high-performance gas chromatography, nuclear magnetic resonance and capillary electrophoresis are also discussed through this article. This review study also compiles various synthesis pathways of SCFAs from diverse substrates such as sugar, acetone, ethanol and amino acids. The different pathways through which SCFAs enter cells for immune response regulation are also highlighted. A major emphasis is the discussion on diseases associated with SCFA dysregulation, such as anaemia, brain development, CRC, depression, obesity and diabetes. This includes exploring the relationship between SCFA levels across ethnicities and their connection with blood pressure and CRC. In conclusion, this review highlights the critical role of SCFAs in maintaining gut health and their implications in various diseases, emphasizing the need for further research on SCFA detection, synthesis and their potential as diagnostic biomarkers. Future studies of SCFAs will pave the way for the development of novel diagnostic tools and therapeutic strategies for optimizing gut health and preventing diseases associated with SCFA dysregulation., (© 2024 John Wiley & Sons Ltd.)

Aims Atrial fibrillation (AF), the most prevalent clinical arrhythmia, is associated with atrial remodelling manifesting as acute and chronic alterations in expression, function, and regulation of atrial electrophysiological and Ca2+-handling processes. These AF-induced modifications crosstalk and propagate across spatial scales creating a complex pathophysiological network, which renders AF resistant to existing pharmacotherapies that predominantly target transmembrane ion channels. Developing innovative therapeutic strategies requires a systems approach to disentangle quantitatively the pro-arrhythmic contributions of individual AF-induced alterations. Methods and results Here, we built a novel computational framework for simulating electrophysiology and Ca2+-handling in human atrial cardiomyocytes and tissues, and their regulation by key upstream signalling pathways [i.e. protein kinase A (PKA), and Ca2+/calmodulin-dependent protein kinase II (CaMKII)] involved in AF-pathogenesis. Populations of atrial cardiomyocyte models were constructed to determine the influence of subcellular ionic processes, signalling components, and regulatory networks on atrial arrhythmogenesis. Our results reveal a novel synergistic crosstalk between PKA and CaMKII that promotes atrial cardiomyocyte electrical instability and arrhythmogenic triggered activity. Simulations of heterogeneous tissue demonstrate that this cellular triggered activity is further amplified by CaMKII- and PKA-dependent alterations of tissue properties, further exacerbating atrial arrhythmogenesis. Conclusions Our analysis reveals potential mechanisms by which the stress-associated adaptive changes turn into maladaptive pro-arrhythmic triggers at the cellular and tissue levels and identifies potential anti-AF targets. Collectively, our integrative approach is powerful and instrumental to assemble and reconcile existing knowledge into a systems network for identifying novel anti-AF targets and innovative approaches moving beyond the traditional ion channel-based strategy. [ABSTRACT FROM AUTHOR]

Background/Aim: Cartilage tissue engineering has been popularly applied in the treatment of articular cartilage defect because it is more effective in generating functional engineered cartilage than traditional methods. Although the chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells (BM-MSCs) is well established, it is often accompanied by undesired hypertrophy. Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a crucial mediator in the ion channel pathway which is known to be involved in chondrogenic hypertrophy. Therefore, this study aimed to reduce the hypertrophy of BMMSCs by inhibiting CaMKII activation. Materials and Methods: BM-MSCs were cultured in three-dimensional (3D) scaffold under chondrogenic induction with and without CaMKII inhibitor, KN-93. After cultivation, markers of chondrogenesis and hypertrophy were investigated. Results: KN-93 at a concentration of 2.0 µM had no effect on the viability of BM-MSCs, while the activation of CaMKII was suppressed. A long period of KN-93 treatment significantly up-regulated the expression of SRY-box transcription factor 9 and aggrecan on day 28 compared to untreated BM-MSCs, Furthermore, KN-93 treatment significantly down-regulated the expression of RUNX family transcription factor 2 and collagen type X alpha 1 chain on days 21 and 28. Immunohistochemistry showed increased expression of aggrecan and type II collagen while the expression of type X collagen was reduced. Conclusion: A CaMKII inhibitor, KN-93 is able to enhance chondrogenesis of BM-MSCs and suppress chondrogenic hypertrophy, suggesting its potential applicability in cartilage tissue engineering. [ABSTRACT FROM AUTHOR]

Purpose of Review: Cognitive impairment is associated with obesity, sarcopenia, and osteoporosis. However, no critical appraisal of the literature on the relationship between musculoskeletal deficits and cognitive impairment, focusing on the epidemiological evidence and biological mechanisms, has been published to date. Herein, we critically evaluate the literature published over the past 3 years, emphasizing interesting and important new findings, and provide an outline of future directions that will improve our understanding of the connections between the brain and the musculoskeletal system. Recent Findings: Recent literature suggests that musculoskeletal deficits and cognitive impairment share pathophysiological pathways and risk factors. Cytokines and hormones affect both the brain and the musculoskeletal system; yet, lack of unified definitions and standards makes it difficult to compare studies. Summary: Interventions designed to improve musculoskeletal health are plausible means of preventing or slowing cognitive impairment. We highlight several musculoskeletal health interventions that show potential in this regard. [ABSTRACT FROM AUTHOR]

After a single extracellular 100 mM calcium pulse (final concentration), wild type S. cerevisiae exhibits a sharp peak in cytosolic calcium. The concentration drops rapidly in these cells as the calcium is sequestered away in the endoplasmic reticulum, Golgi, and vacuoles leaving resting cytosolic levels higher than their original state, followed by changes in gene expression. In cells lacking calmodulin kinase 2 (Cmk2p), a secondary rise in cytosolic calcium concentration is seen after extracellular calcium increases and the cytosolic calcium is subsequently sequestered. Utilizing double deletions, we demonstrate that Cmk2p is modulating the activity of Rch1p, a known inhibitor of Channel X which is a yeast plasma membrane channel through which calcium ions are transported after an extracellular calcium pulse. We hypothesize that Cmk2p is acting as a regulator of Channel X by activating Rch1p and without CMK2, Channel X inactivation does not occur fully. [ABSTRACT FROM AUTHOR]

Summary : Stearoyl-CoA desaturase (SCD) is a potential therapeutic target for Parkinson's and related neurodegenerative diseases. SCD inhibition ameliorates neuronal toxicity caused by aberrant α-synuclein, a lipid-binding protein implicated in Parkinson's disease. Its inhibition depletes monounsaturated fatty acids, which may modulate α-synuclein conformations and membrane interactions. Herein, we characterize the pharmacokinetic and pharmacodynamic properties of YTX-7739, a clinical-stage SCD inhibitor. Administration of YTX-7739 to rats and monkeys for 15 days caused a dose-dependent increase in YTX-7739 concentrations that were well-tolerated and associated with concentration-dependent reductions in the fatty acid desaturation index (FADI), the ratio of monounsaturated to saturated fatty acids. An approximate 50% maximal reduction in the carbon-16 desaturation index was observed in the brain, with comparable responses in the plasma and skin. A study with a diet supplemented in SCD products indicates that changes in brain C16 desaturation were due to local SCD inhibition, rather than to changes in systemic fatty acids that reach the brain. Assessment of pharmacodynamic response onset and reversibility kinetics indicated that approximately 7 days of dosing were required to achieve maximal responses, which persisted for at least 2 days after cessation of dosing. YTX-7739 thus achieved sufficient concentrations in the brain to inhibit SCD and produce pharmacodynamic responses that were well-tolerated in rats and monkeys. These results provide a framework for evaluating YTX-7739 pharmacology clinically as a disease-modifying therapy to treat synucleinopathies. [ABSTRACT FROM AUTHOR]

Aims There is a lack of diagnostic and therapeutic options for patients with atrial cardiomyopathy and paroxysmal atrial fibrillation. Interestingly, an abnormal P-wave terminal force in electrocardiogram lead V1 (PTFV1) has been associated with atrial cardiomyopathy, but this association is poorly understood. We investigated PTFV1 as a marker for functional, electrical, and structural atrial remodelling. Methods and results Fifty-six patients with acute myocardial infarction and 13 kidney donors as control cohort prospectively underwent cardiac magnetic resonance imaging to evaluate the association between PTFV1 and functional remodelling (atrial strain). To further investigate underlying pathomechanisms, right atrial appendage biopsies were collected from 32 patients undergoing elective coronary artery bypass grafting. PTFV1 was assessed as the product of negative P-wave amplitude and duration in lead V1 and defined as abnormal if ≥4000 ms*μV. Activity of cardiac Ca/calmodulin-dependent protein kinase II (CaMKII) was determined by a specific HDAC4 pull-down assay as a surrogate for electrical remodelling. Atrial fibrosis was quantified using Masson's trichrome staining as a measure for structural remodelling. Multivariate regression analyses were performed to account for potential confounders. A total of 16/56 (29%) of patients with acute myocardial infarction, 3/13 (23%) of kidney donors, and 15/32 (47%) of patients undergoing coronary artery bypass grafting showed an abnormal PTFV1. In patients with acute myocardial infarction, left atrial (LA) strain was significantly reduced in the subgroup with an abnormal PTFV1 (LA reservoir strain: 32.28 ± 12.86% vs. 22.75 ± 13.94%, P = 0.018; LA conduit strain: 18.87 ± 10.34% vs. 10.17 ± 8.26%, P = 0.004). Abnormal PTFV1 showed a negative correlation with LA conduit strain independent from clinical covariates (coefficient B: −7.336, 95% confidence interval −13.577 to −1.095, P = 0.022). CaMKII activity was significantly increased from (normalized to CaMKII expression) 0.87 ± 0.17 to 1.46 ± 0.15 in patients with an abnormal PTFV1 (P = 0.047). This increase in patients with an abnormal PTFV1 was independent from clinical covariates (coefficient B: 0.542, 95% confidence interval 0.057 to 1.027, P = 0.031). Atrial fibrosis was significantly lower with 12.32 ± 1.63% in patients with an abnormal PTFV1 (vs. 20.50 ± 2.09%, P = 0.006), suggesting PTFV1 to be a marker for electrical but not structural remodelling. Conclusions Abnormal PTFV1 is an independent predictor for impaired atrial function and for electrical but not for structural remodelling. PTFV1 may be a promising tool to evaluate patients for atrial cardiomyopathy and for risk of atrial fibrillation [ABSTRACT FROM AUTHOR]

Cancer remains the second leading cause of mortality worldwide. In the course of this multistage and multifactorial disease, a set of alterations takes place, with genetic and environmental factors modulating tumorigenesis and disease progression. Metabolic alterations of tumors are well-recognized and are considered as one of the hallmarks of cancer. Cancer cells adapt their metabolic competences in order to efficiently supply their novel demands of energy to sustain cell proliferation and metastasis. At present, there is a growing interest in understanding the metabolic switch that occurs during tumorigenesis. Together with the Warburg effect and the increased glutaminolysis, lipid metabolism has emerged as essential for tumor development and progression. Indeed, several investigations have demonstrated the consequences of lipid metabolism alterations in cell migration, invasion, and angiogenesis, three basic steps occurring during metastasis. In addition, obesity and associated metabolic alterations have been shown to augment the risk of cancer and to worsen its prognosis. Consequently, an extensive collection of tumorigenic steps has been shown to be modulated by lipid metabolism, not only affecting the growth of primary tumors, but also mediating progression and metastasis. Besides, key enzymes involved in lipid-metabolic pathways have been associated with cancer survival and have been proposed as prognosis biomarkers of cancer. In this review, we will analyze the impact of obesity and related tumor microenviroment alterations as modifiable risk factors in cancer, focusing on the lipid alterations co-occurring during tumorigenesis. The value of precision technologies and its application to target lipid metabolism in cancer will also be discussed. The degree to which lipid alterations, together with current therapies and intake of specific dietary components, affect risk of cancer is now under investigation, and innovative therapeutic or preventive applications must be explored. [ABSTRACT FROM AUTHOR]

The adipocytokine resistin is released from epicardial adipose tissue (EAT). Plasma resistin and EAT deposition are independently associated with atrial fibrillation. The EAT secretome enhances arrhythmia susceptibility and inotropy of human myocardium. Therefore, we aimed to determine the effect of resistin on the function of human myocardium and how resistin contributes to the proarrhythmic effect of EAT. EAT biopsies were obtained from 25 cardiac surgery patients. Resistin levels were measured by ELISA in 24-h EAT culture media (n = 8). The secretome resistin concentrations increased over the culture period to a maximal level of 5.9 ± 1.2 ng/mL. Coculture with β-adrenergic agonists isoproterenol (n = 4) and BRL37344 (n = 13) had no effect on EAT resistin release. Addition of resistin (7, 12, 20 ng/mL) did not significantly increase the spontaneous contraction propensity of human atrial trabeculae (n = 10) when given alone or in combination with isoproterenol. Resistin dose-dependently increased trabecula-developed force (maximal 2.9-fold increase, P < 0.0001), as well as the maximal rates of contraction (2.6-fold increase, P = 0.002) and relaxation (1.8-fold increase, P = 0.007). Additionally, the postrest potentiation capacity of human trabeculae was reduced at all resistin doses, suggesting that the inotropic effect induced by resistin might be due to altered sarcoplasmic reticulum Ca2+ handling. EAT resistin release is not modulated by common arrhythmia triggers. Furthermore, exogenous resistin does not promote arrhythmic behavior in human atrial trabeculae. Resistin does, however, induce an acute dose-dependent positive inotropic and lusitropic effect. [ABSTRACT FROM AUTHOR]

Triazolopyridinone derivatives are of high value in both medicinal and material chemistry. However, the chiral or hindered triazolopyridinone derivatives remain an underexplored area of chemical space because they are difficult to prepare via conventional methods. Here we report an electrochemical rearrangement for the efficient synthesis of otherwise inaccessible triazolopyridinones with diverse alkyl carboxylic acids as starting materials. This enables the efficient preparation of more than 60 functionalized triazolopyridinones under mild conditions in a sustainable manner. This method is evaluated for the late stage modification of bioactive natural products, amino acids and pharmaceuticals, and it is further applied to the decagram scale preparation of enantiopure triazolopyridinones. The control experiments support a mechanism involving an oxidative cyclization and 1,2-carbon migration. This facile and scalable rearrangement demonstrates the power of electrochemical synthesis to access otherwise-inaccessible triazolopyridinones and may find wide application in organic, material and medicinal chemistry. Chiral and hindered triazolopyridinone derivatives are an underexplored area of chemical space mainly due to their challenging synthesis via classical methods. Here, the authors report an electrochemical rearrangement for the synthesis of triazolopyridinones using diverse, available alkyl carboxylic acids as starting materials. [ABSTRACT FROM AUTHOR]

Aims Despite improvements in patient identification and management, heart failure (HF) remains a major public health burden and an important clinical challenge. A variety of animal and human studies have provided evidence suggesting a central role of calcium/calmodulin-dependent protein kinase II (CaMKII) in the development of pathological cardiac remodelling and HF. Here, we describe a new potent, selective, and orally available CaMKII inhibitor. Methods and results Chemical optimization led to the identification of RA306 as a selective CaMKII inhibitor. This compound was found potent on the cardiac CaMKII isoforms delta and gamma (IC50 in the 10 nM range), with pharmacokinetic properties allowing oral administration in animal models of HF. RA306 was administered to diseased mice carrying a mutation in alpha-actin that is responsible for dilated cardiomyopathy (DCM) in humans. In two separate studies, RA306 was orally administered at 30 mg/kg either for 2 weeks (twice a day) or for 2 months (once a day). Echocardiography monitoring showed that RA306 significantly improved cardiac function (ejection fraction and cardiac output) as compared to vehicle. These disease modifying effects of RA306 were associated with inhibition of cardiac phosphorylation of phospholamban (PLN) at threonine-17, indicating reduced cardiac CaMKII activity. Conclusion This work supports the feasibility of identifying potent orally available CaMKII inhibitors suitable for clinical use to treat heart disease. [ABSTRACT FROM AUTHOR]

Epicardial adipose tissue (EAT) deposition has a strong clinical association with atrial arrhythmias; however, whether a direct functional interaction exists between EAT and the myocardium to induce atrial arrhythmias is unknown. Therefore, we aimed to determine whether human EAT can be an acute trigger for arrhythmias in human atrial myocardium. Human trabeculae were obtained from right atrial appendages of patients who have had cardiac surgery (n = 89). The propensity of spontaneous contractions (SCs) in the trabeculae (proxy for arrhythmias) was determined under physiological conditions and during known triggers of SCs (high Ca2+, β-adrenergic stimulation). To determine whether EAT could trigger SCs, trabeculae were exposed to superfusate of fresh human EAT, and medium of 24 h-cultured human EAT treated with β1/2 (isoproterenol) or β3 (BRL37344) adrenergic agonists. Without exposure to EAT, high Ca2+ and β1/2-adrenergic stimulation acutely triggered SCs in, respectively, 47% and 55% of the trabeculae that previously were not spontaneously active. Acute β3-adrenergic stimulation did not trigger SCs. Exposure of trabeculae to either superfusate of fresh human EAT or untreated medium of 24 h-cultured human EAT did not induce SCs; however, specific β3-adrenergic stimulation of EAT did trigger SCs in the trabeculae, either when applied to fresh (31%) or cultured (50%) EAT. Additionally, fresh EAT increased trabecular contraction and relaxation, whereas media of cultured EAT only increased function when treated with the β3-adrenergic agonist. An acute functional interaction between human EAT and human atrial myocardium exists that increases the propensity for atrial arrhythmias, which depends on β3-adrenergic rather than β1/2-adrenergic stimulation of EAT. [ABSTRACT FROM AUTHOR]

Background: Familial hemiplegic migraine (FHM) is a group of genetic migraine, associated with hemiparesis and aura. Three causative different genes have been identified, all of which are involved in membrane ion transport. Among these, SCN1A encodes the voltage-gated Na+ channel Nav1.1, and FHM caused by mutations of SCN1A is named FHM3. For 7 of the 12 known FHM3-causing SCNA1 mutations functional consequences have been investigated, and even if gain of function effect seems to be a predominant phenotype, for several mutations conflicting results have been obtained and the available data do not reveal a univocal FHM3 pathomechanism. Methods: To obtain a more complete picture, here, we characterized by patch clamp approach the remaining 5 mutations (Q1489H, I1498M, F1499 L, M1500 V, F1661 L) in heterologous expression systems. Results: With the exception of I1498M, all mutants exhibited the same current density as WT and exhibited a shift of the steady state inactivation to more positive voltages, an accelerated recovery from inactivation, and an increase of the persistent current, revealing that most FHM3 mutations induce a gain of function. We also determined the effect of GS967, a late Na+ current blocker, on the above mentioned mutants as well as on previously characterized ones (L1649Q, L1670 W, F1774S). GS967 inhibited persistent currents of all SCNA1 FMH3-related mutants and dramatically slowed the recovery from fast inactivation of WT and mutants, consistent with the hypothesis that GS967 specifically binds to and thereby stabilizes the fast inactivated state. Simulation of neuronal firing showed that enhanced persistent currents cause an increase of ionic fluxes during action potential repolarization and consequent accumulation of K+ and/or exhaustion of neuronal energy resources. In silico application of GS967 largely reduced net ionic currents in neurons without impairing excitability. Conclusion: In conclusion, late Na+ current blockers appear a promising specific pharmacological treatment of FHM3. [ABSTRACT FROM AUTHOR]

Urinary bladder neoplasm is one of the most common cancers worldwide. Cancer stem cells (CSCs) have been proven to be an important cause of cancer progression and poor prognosis. In the present study, we established bladder CSCs and identified the crucial differentially expressed genes (DEGs) between these cells and parental bladder cancer cells. Analyses of bioinformatics data and clinical samples from local hospitals showed that stearoyl CoA desaturase‐1 (SCD) was the key factor among the DEGs. A significant correlation between SCD gene expression and poor prognosis among patients with bladder cancer was observed in our data. Loss‐of‐function experiments further revealed that the SCD inhibitor A939572 and SCD gene interference reduced cell proliferation and invasion. The above data suggest that SCD may serve as a novel marker for the prediction of tumour progression and poor prognosis in patients with bladder cancer. [ABSTRACT FROM AUTHOR]

Ca2+/calmodulin-dependent protein kinase II (CAMKIIδ) belongs to the serine/threonine kinase family, which is involved in a broad range of cellular events in cell survival and proliferation as well as a number of other signal transduction pathways. Thus, it is regarded a promising target for treatment of cancers. In the present paper, a three-dimensional quantitative structure-activity relationship and molecular docking were applied to investigate a series of new CAMKIIδ inhibitors of pyrazolopyrimidine derivatives. The determination coefficient (R2) and leave-one-out cross-validation coefficient (Q2) of CoMSIA model are 0.676 and 0.956, respectively. The predictive ability of this model was evaluated by the external validation using a test set of eight compounds with a predicted determination coefficient Rtest2 of 0.80, besides the mean absolute error of the test set was 0.328 log units. Docking results are in concordance with CoMSIA contour maps, gave the information for interactive mode exploration. Based on those satisfactory results, newly designed molecules were predicted with highly potent CAMKIIδ inhibitory activity, additionally, they have showed promising results in the preliminary in silico ADMET evaluations. This study could expand our understanding of pyrazolopyrimidine derivatives as inhibitors of CAMKIIδ and would be of great help in lead optimization for early drug discovery of highly potent CAMKIIδ inhibitors. [ABSTRACT FROM AUTHOR]

The reaction of methyl 2-isothiocyanatobenzoate and 1-azido-3-(4-substituted phenyl)propan-2-ones in the presence of triphenyl phosphine in dioxane by heating produced tricyclic (Z)-2-(4-substituted benzylidene)-2,3-dihydro-5H-oxazolo[2,3-b]quinazolin-5-ones instead of the expected methyl 2-{[5-(4-substituted benzyl)oxazol-2-yl]amino}benzoates. A one-pot procedure for the synthesis of 2-substituted 5H-oxazolo[2,3-b]quinazolin-5-ones from appropriate azidomethyl ketones and 2-isothiocyanatobenzoate was developed. [ABSTRACT FROM AUTHOR]

Purpose: Mechanical stretch increases sodium and calcium entry into myocytes and activates the late sodium current. GS967, a triazolopyridine derivative, is a sodium channel blocker with preferential effects on the late sodium current. The present study evaluates whether GS967 inhibits or modulates the arrhythmogenic electrophysiological effects of myocardial stretch.Methods: Atrial and ventricular refractoriness and ventricular fibrillation modifications induced by acute stretch were studied in Langendorff-perfused rabbit hearts (n = 28) using epicardial multiple electrodes and high-resolution mapping techniques under control conditions and during the perfusion of GS967 at different concentrations (0.03, 0.1, and 0.3 μM).Results: On comparing ventricular refractoriness, conduction velocity and wavelength obtained before stretch had no significant changes under each GS967 concentration while atrial refractoriness increased under GS967 0.3 μM. Under GS967, the stretch-induced changes were attenuated, and no significant differences were observed between before and during stretch. GS967 0.3 μM diminished the normal stretch-induced changes resulting in longer (less shortened) atrial refractoriness (138 ± 26 ms vs 95 ± 9 ms; p < 0.01), ventricular refractoriness (155 ± 18 ms vs 124 ± 16 ms; p < 0.01) and increments in spectral concentration (23 ± 5% vs 17 ± 2%; p < 0.01), the fifth percentile of ventricular activation intervals (46 ± 8 ms vs 31 ± 3 ms; p < 0.05), and wavelength of ventricular fibrillation (2.5 ±0.5 cm vs 1.7 ± 0.3 cm; p < 0.05) during stretch. The stretch-induced increments in dominant frequency during ventricular fibrillation (control = 38%, 0.03 μM = 33%, 0.1 μM = 33%, 0.3 μM = 14%; p < 0.01) and the stretch-induced increments in arrhythmia complexity index (control = 62%, 0.03μM = 41%, 0.1 μM = 32%, 0.3 μM = 16%; p < 0.05) progressively decreased on increasing the GS967 concentration.Conclusions: GS967 attenuates stretch-induced changes in cardiac electrophysiology. [ABSTRACT FROM AUTHOR]

While it is understood that body composition impacts on physical conditions, such as diabetes and cardiovascular disease, it is only now apparent that body composition might play a role in the genesis of common mental disorders, depression and anxiety. Sarcopenia occurs in ageing and comprises a progressive decline in muscle mass, strength and function, leading to frailty, decreased independence and poorer quality of life. This review presents an emerging body of evidence to support the hypothesis that shared pathophysiological pathways for sarcopenia and the common mental disorders constitute links between skeletal muscle and brain function. Contracting skeletal muscle secretes neurotrophic factors that are known to play a role in mood and anxiety, and have the dual role of nourishing neuronal growth and differentiation, while protecting the size and number of motor units in skeletal muscle. Furthermore, skeletal muscle activity has important immune and redox effects that impact behaviour and reduce muscle catabolism. [ABSTRACT FROM AUTHOR]

The pathway for unsaturated fatty acid biosynthesis is essential in trypanosomatid parasites and has been a key target in our work on the discovery and analysis of several inhibitory compounds. Here, we show the effect of novel inhibitors of stearoyl-CoA desaturase (SCD) and oleate desaturase (OD), alone and in combination, on the growth rate of parasite cultures. GS-456332, an inhibitor of human Δ9 desaturase, efficiently inhibited growth of both Trypanosoma cruzi epimastigotes and Trypanosoma brucei bloodstream form cells, with EC values of 136.9 ± 24.2 and 9.4 ± 3.1 nM, respectively. This effect was specific for SCD. Stearolic acid (9-octadecynoic acid) was also able to arrest T. cruzi and T. brucei growth by specific inhibition of their OD, with EC values of 1.0 ± 0.2 μM and 0.1 ± 0.01 μM, respectively. When these compounds were administered simultaneously, a clearly synergistic effect was observed for both Trypanosoma species, with EC values in the low nanomolar range. These results demonstrate the feasibility of using combinations of drugs, inhibiting different enzymes on the same metabolic pathway, for the development of more efficient chemotherapeutic strategies against neglected diseases caused by these parasites. [ABSTRACT FROM AUTHOR]

Endoplasmic reticulum (ER) stress sensors use a related luminal domain to monitor the unfolded protein load and convey the signal to downstream effectors, signaling an unfolded protein response (UPR) that maintains compartment-specific protein folding homeostasis. Surprisingly, perturbation of cellular lipid composition also activates the UPR, with important consequences in obesity and diabetes. However, it is unclear if direct sensing of the lipid perturbation contributes to UPR activation. We found that mutant mammalian ER stress sensors, IRE1a and PERK, lacking their luminal unfolded protein stress-sensing domain, nonetheless retained responsiveness to increased lipid saturation. Lipid saturation-mediated activation in cells required an ER-spanning transmembrane domain and was positively regulated in vitro by acyl-chain saturation in reconstituted liposomes. These observations suggest that direct sensing of the lipid composition of the ER membrane contributes to the UPR. [ABSTRACT FROM AUTHOR]

Background: Cancer cells present a sustained de novo fatty acid synthesis with an increase of saturated and monounsaturated fatty acid (MUFA) production. This change in fatty acid metabolism is associated with overexpression of stearoyl-CoA desaturase 1 (Scd1), which catalyses the transformation of saturated fatty acids into monounsaturated fatty acids (e.g., oleic acid). Several reports demonstrated that inhibition of Scd1 led to the blocking of proliferation and induction of apoptosis in cancer cells. Nevertheless, mechanisms of cell death activation remain to be better understood. Principal Findings: In this study, we demonstrated that Scd1 extinction by siRNA triggered abolition of de novo MUFA synthesis in cancer and non-cancer cells. Scd1 inhibition-activated cell death was only observed in cancer cells with induction of caspase 3 activity and PARP-cleavage. Exogenous supplementation with oleic acid did not reverse the Scd1 ablation-mediated cell death. In addition, Scd1 depletion induced unfolded protein response (UPR) hallmarks such as Xbp1 mRNA splicing, phosphorylation of eIF2α and increase of CHOP expression. However, the chaperone GRP78 expression, another UPR hallmark, was not affected by Scd1 knockdown in these cancer cells indicating a peculiar UPR activation. Finally, we showed that CHOP induction participated to cell death activation by Scd1 extinction. Indeed, overexpression of dominant negative CHOP construct and extinction of CHOP partially restored viability in Scd1-depleted cancer cells. Conclusion: These results suggest that inhibition of de novo MUFA synthesis by Scd1 extinction could be a promising anticancer target by inducing cell death through UPR and CHOP activation. [ABSTRACT FROM AUTHOR]

Lung cancer is the most frequent form of cancer. The survival rate for patients with metastatic lung cancer is ∼5%, hence alternative therapeutic strategies to treat this disease are critically needed. Recent studies suggest that lipid biosynthetic pathways, particularly fatty acid synthesis and desaturation, are promising molecular targets for cancer therapy. We have previously reported that inhibition of stearoylCoA desaturase-1 (SCD1), the enzyme that produces monounsaturated fatty acids (MUFA), impairs lung cancer cell proliferation, survival and invasiveness, and dramatically reduces tumor formation in mice. In this report, we show that inhibition of SCD activity in human lung cancer cells with the small molecule SCD inhibitor CVT-11127 reduced lipid synthesis and impaired proliferation by blocking the progression of cell cycle through the G1/S boundary and by triggering programmed cell death. These alterations resulting from SCD blockade were fully reversed by either oleic (18:1n-9), palmitoleic acid (16:1n-7) or cis-vaccenic acid (18:1n-7) demonstrating that cis-MUFA are key molecules for cancer cell proliferation. Additionally, co-treatment of cells with CVT-11127 and CP-640186, a specific acetylCoA carboxylase (ACC) inhibitor, did not potentiate the growth inhibitory effect of these compounds, suggesting that inhibition of ACC or SCD1 affects a similar target critical for cell proliferation, likely MUFA, the common fatty acid product in the pathway. This hypothesis was further reinforced by the observation that exogenous oleic acid reverses the anti-growth effect of SCD and ACC inhibitors. Finally, exogenous oleic acid restored the globally decreased levels of cell lipids in cells undergoing a blockade of SCD activity, indicating that active lipid synthesis is required for the fatty acid-mediated restoration of proliferation in SCD1-inhibited cells. Altogether, these observations suggest that SCD1 controls cell cycle progression and apoptosis and, consequently, the overall rate of proliferation in cancer cells through MUFA-mediated activation of lipid synthesis. [ABSTRACT FROM AUTHOR]

Cancer cells activate the biosynthesis of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) in order to sustain an increasing demand for phospholipids with appropriate acyl composition during cell replication. We have previously shown that a stable knockdown of stearoyl-CoA desaturase 1 (SCD1), the main Δ9-desaturase that converts SFA into MUFA, in cancer cells decreases the rate of lipogenesis, reduces proliferation and in vitro invasiveness, and dramatically impairs tumor formation and growth. Here we report that pharmacological inhibition of SCD1 with a novel small molecule in cancer cells promoted the activation of AMP-activated kinase (AMPK) and the subsequent reduction of acetylCoA carboxylase activity, with a concomitant inhibition of glucose-mediated lipogenesis. The pharmacological inhibition of AMPK further decreased proliferation of SCD1-depleted cells, whereas AMPK activation restored proliferation to control levels. Addition of supraphysiological concentrations of glucose or pyruvate, the end product of glycolysis, did not reverse the low proliferation rate of SCD1-ablated cancer cells. Our data suggest that cancer cells require active SCD1 to control the rate of glucose-mediated lipogenesis, and that when SCD1 activity is impaired cells downregulate SFA synthesis via AMPK-mediated inactivation of acetyl-CoA carboxylase, thus preventing the harmful effects of SFA accumulation. [ABSTRACT FROM AUTHOR]

Ventricular arrhythmia (VA) is a highly fatal arrhythmia that involves multiple ion channels. Of all sudden cardiac death events, ~85% result from VAs, including ventricular tachycardia and ventricular fibrillation. Calcium/calmodulin-dependent pro-tein kinase II (CaMKII) is an important ion channel regulator that participates in the excitation-contraction coupling of the heart, and as such is important for regulating its electrophysiological function. CaMKII can be activated in a Ca2+/calmodulin (CaM)-dependent or Ca2+/CaM-independent manner, serving a key role in the occurrence and development of VA. The present review aimed to determine whether activated CaMKII induces early afterdepolarizations and delayed afterdepolarizations that result in VA by regulating sodium, potassium and calcium ions. Assessing VA mechanisms based on the CaMKII pathway is of great significance to the clinical treatment of VA and the de-velopment of effective drugs for use in clinical practice. [ABSTRACT FROM AUTHOR]