We established that acute adrenergic receptor stimulation in β-cells suppresses oxidative metabolism. This effect provides the basis for understanding how CAs reduce cell proliferation. Furthermore, the effects of acute CA on Min6 cells were distinguished from chronic CA culture using proteomics. Together, the RNAseq, qPCR and proteomic studies support a role for adrenergic receptor signaling in the regulation of proliferaton in β-cells. This work describes the genetic and proteomic profile underlying chronic adrenergic signaling and identifies CA independent suppression of β-cell growth and metabolism. Through the use of multiple models and comparative bioinformatics, we refined the list of molecular dysfunctions associated with the IUGR pathology to a set of specific and testable adrenergic targets.

and keywords The aim of this work was to evaluate the effect on rat myocardial β-adrenergic system of short-term (10 hours and 3 days) and long-term (5 weeks) cold exposure of rats with possible subsequent two-week recovery at normal temperature. The subtypes of β-adrenergic receptors (β-AR), their cognate G-proteins and adenylate cyclase have been characterized. β-AR are important components of cardiac regulatory mechanisms. They are involved in stimulating G-protein (Gs) and adenylate cyclase to increase cardiac contractility and frequency during stressful situations, including cold exposure. Heart tissue contains all three β-AR subtypes (β1-AR, β2-AR, β3-AR). While β1-AR couples with only Gs, β2-AR and β3-AR interact with the inhibitory G-protein (Gi). Electrophoresis and Western blotting showed a significant increase in β1-AR after a three-day exposure to cold. There was also a significant increase in β3-AR concentrations after a five-week cold exposure and this increase lasted for two weeks. There were no significant changes in the amnounts of β-AR cognate G-proteins (Gαs, Gβ, Gαi1/2 a Gαi3). In contrast, expression of adenylyl cyclase isoform V and VI significantly decreased during short-term exposure to cold. Using the saturation experiment with the β-antagonist [3H]CGP 12177, β-AR were...

Acute cold exposure is a significant stressor activating heat production by shivering after the prolonged exposure cellular oxidative stress increases. Chronic exposure to cold lasting at least 2 weeks leads to the development of cold acclimatization. The main thermogenic role is taken over by non-shivering thermogenesis taking place in brown adipose tissue, which significantly increases its weight due to cold. Cardiac hypertrophy, hypertension and impaired renal function are frequently observed pathologies of acclimatization at 4-5 řC. Our laboratory recently introduced a model of mild chronic cold acclimatization at 8 řC, during which no damage to the heart or kidneys occurs and has proven cardioprotective effect on reducing infarct size. Hence, the influence of this cold acclimatization model on the other cellular and molecular processes needs to be investigated. The cardioprotective effect of cold acclimatization includes changes in β-AR signaling, activation of anti-apoptotic pathways or augmentation of the antioxidant system. The aim of this thesis was to investigate the effect of cold acclimation and subsequent reacclimation on proteins regulating Ca2+ levels in the rat heart (SERCA2 and phospholamban) and on the stimulation of regulatory proteins β-arrestin 1/2 and protein kinase PDPK1. The...

yes / Ca2+ release from the Golgi apparatus regulates key functions of the organelle, including vesicle trafficking. However, the signaling pathways that control this form of Ca2+ release are poorly understood and evidence of discrete Golgi Ca2+ release events is lacking. Here, we identified the Golgi apparatus as the source of prolonged Ca2+ release events that originate from the nuclear ‘poles’ of primary cardiac cells. Once initiated, Golgi Ca2+ release was unaffected by global depletion of sarcoplasmic reticulum Ca2+, and disruption of the Golgi apparatus abolished Golgi Ca2+ release without affecting sarcoplasmic reticulum function, suggesting functional and anatomical independence of Golgi and sarcoplasmic reticulum Ca2+ stores. Maximal activation of β1-adrenoceptors had only a small stimulating effect on Golgi Ca2+ release. However, inhibition of phosphodiesterase (PDE) 3 or 4, or downregulation of PDE 3 and 4 in heart failure markedly potentiated β1-adrenergic stimulation of Golgi Ca2+ release, consistent with compartmentalization of cAMP signaling within the Golgi apparatus microenvironment. β1-adrenergic stimulation of Golgi Ca2+ release involved activation of both Epac and PKA signaling pathways and CaMKII. Interventions that stimulated Golgi Ca2+ release induced trafficking of vascular growth factor receptor-1 (VEGFR-1) from the Golgi apparatus to the surface membrane. These data establish the Golgi apparatus as a juxtanuclear focal point for Ca2+ and β1-adrenergic signaling, which functions independently from the sarcoplasmic reticulum and the global Ca2+ transients that underlie the primary contractile function of the cell.