Search results for "beta"
showing 10 items of 3374 documents
β3-Adrenoceptor agonists for overactive bladder syndrome: Role of translational pharmacology in a repositioning clinical drug development project
2016
β3-Adrenoceptor agonists were originally considered as a promising drug class for the treatment of obesity and/or type 2 diabetes. When these development efforts failed, they were repositioned for the treatment of the overactive bladder syndrome. Based on the example of the β3-adrenoceptor agonist mirabegron, but also taking into consideration evidence obtained with ritobegron and solabegron, we discuss challenges facing a translational pharmacology program accompanying clinical drug development for a first-in-class molecule. Challenges included generic ones such as ligand selectivity, species differences and drug target gene polymorphisms. Challenges that are more specific included changin…
β(3)‐Adrenoceptors in the normal and diseased urinary bladder—What are the open questions?
2019
β(3)‐Adrenoceptor agonists are used in the treatment of overactive bladder syndrome. Although the relaxant response to adrenergic stimulation in human detrusor smooth muscle cells is mediated mainly via β(3)‐adrenoceptors, the plasma concentrations of the therapeutic dose of mirabegron, the only clinically approved β(3)‐adrenoceptor agonist, are considerably lower than the EC(50) for causing direct relaxation of human detrusor, suggesting a mechanism of action other than direct relaxation of detrusor smooth muscle. However, the site and mechanism of action of β(3)‐adrenoceptor agonists in the bladder have not been firmly established. Postulated mechanisms include prejunctional suppression o…
Tocotrienol Affects Oxidative Stress, Cholesterol Homeostasis and the Amyloidogenic Pathway in Neuroblastoma Cells: Consequences for Alzheimer’s Dise…
2016
One of the characteristics of Alzheimer´s disease (AD) is an increased amyloid load and an enhanced level of reactive oxidative species (ROS). Vitamin E has known beneficial neuroprotective effects, and previously, some studies suggested that vitamin E is associated with a reduced risk of AD due to its antioxidative properties. However, epidemiological studies and nutritional approaches of vitamin E treatment are controversial. Here, we investigate the effect of α-tocotrienol, which belongs to the group of vitamin E, on AD-relevant processes in neuronal cell lines. In line with the literature, α-tocotrienol reduced the ROS level in SH-SY5Y cells. In the presence of tocotrienols, cholesterol…
Direct Sensing of Nutrients via a LAT1-like Transporter in Drosophila Insulin-Producing Cells
2016
Summary Dietary leucine has been suspected to play an important role in insulin release, a hormone that controls satiety and metabolism. The mechanism by which insulin-producing cells (IPCs) sense leucine and regulate insulin secretion is still poorly understood. In Drosophila, insulin-like peptides (DILP2 and DILP5) are produced by brain IPCs and are released in the hemolymph after leucine ingestion. Using Ca2+-imaging and ex vivo cultured larval brains, we demonstrate that IPCs can directly sense extracellular leucine levels via minidiscs (MND), a leucine transporter. MND knockdown in IPCs abolished leucine-dependent changes, including loss of DILP2 and DILP5 in IPC bodies, consistent wit…
Curcumin-like compounds designed to modify amyloid beta peptide aggregation patterns
2017
International audience; Curcumin is a natural polyphenol able to bind the amyloid beta peptide, which is related to Alzheimer's disease, and modify its self-assembly pathway. This paper focuses on a multi-disciplinary study that starts from the design of curcumin-like compounds with the key chemical features required for inhibiting amyloid beta aggregation, and reports the effects of these compounds on the in vitro aggregation of amyloid beta peptides. Chemoinformatic screening was performed through the calculation of molecular descriptors that were able to highlight the drug-like profile, followed by docking studies with an amyloid beta peptide fibril. The computational design underlined t…
The Blood-Brain Barrier in Alzheimer’s Disease
2020
The accumulation of neurotoxic amyloid-beta (Aβ) in the brain is one of the characteristic hallmarks of Alzheimer's disease (AD). Aβ-peptide brain homeostasis is governed by its production and various clearance mechanisms. The blood-brain barrier provides a large surface area for influx and efflux mechanisms into and out of the brain. Different transporters and receptors have been implicated to play crucial roles in Aβ clearance from brain. Besides Aβ transport, the blood-brain barrier tightly regulates the brain's microenvironment; however, vascular alterations have been shown in patients with AD. Here, we summarize how the blood-brain barrier changes during aging and in disease and focus …
Hsp60, amateur chaperone in amyloid-beta fibrillogenesis
2016
BACKGROUND: Molecular chaperones are a very special class of proteins that play essential roles in many cellular processes like folding, targeting and transport of proteins. Moreover, recent evidence indicates that chaperones can act as potentially strong suppressor agents in Alzheimer's disease (AD). Indeed, in vitro experiments demonstrate that several chaperones are able to significantly slow down or suppress aggregation of Aβ peptide and in vivo studies reveal that treatment with specific chaperones or their overexpression can ameliorate some distinct pathological signs characterizing AD. METHODS: Here we investigate using a biophysical approach (fluorescence, circular dichroism (CD), t…
Beyond Amyloid - Widening the View on Alzheimer's Disease
2017
For 25 years, the amyloid cascade hypothesis, based on the finding that mutations in the amyloid precursor protein are closely linked to familial forms of Alzheimer's disease (AD), dominated the research on this disease. Recent failures of clinical anti-amyloidogenic trials, however, substantially support the reasoning (i) that the pathomechanisms that trigger familial AD, namely the generation, aggregation, and deposition of amyloid beta, cannot necessarily be extrapolated to sporadic cases and (ii) that amyloid beta represents a prominent histopathological feature in AD but not its exclusive causative factor. In autumn 2016, the Volkswagen Foundation hosted the Herrenhausen Symposium ‘Bey…
Crosstalk between angiotensin and the nonamyloidogenic pathway of Alzheimer's amyloid precursor protein.
2017
The association between hypertension and an increased risk for Alzheimer's disease (AD) and dementia is well established. Many data suggest that modulation of the renin-angiotensin system may be meaningful for the prevention and therapy of neurodegenerative disorders, in particular AD. Proteolytic cleavage of the amyloid precursor protein (APP) by α-secretase precludes formation of neurotoxic Aβ peptides and is expected to counteract the development of AD. An established approach for the up-regulation of α-secretase cleavage is the activation of G protein-coupled receptors (GPCRs). Therefore, our study aimed to analyze whether stimulation of angiotensin AT1 or AT2 receptors stably expressed…
Renin-Angiotensin System Inhibition in Cardiovascular Patients at the Time of COVID19: Much Ado for Nothing? A Statement of Activity from the Directo…
2020
Cardiovascular diseases, in particular hypertension, as well as the cardiovascular treatment with Renin-Angiotensin System inhibitors such as Angiotensin Converting Enzyme (ACE) inhibitors and Angiotensin Receptor Blockers (ARBs), are claimed once again as mechanisms of Severe Acute Respiratory Syndrome (SARS) during the COVID-19 outbreak due to Cov-2 epidemics. In vitro studies are available to support the eventual role of ACE inhibitors and ARBs in both the promotion and antagonism of the disease. The available literature, indeed, presents contrasting results, all concentrated in experimental models. Evidence in humans is lacking that those mechanisms are actually occurring in the present…