A Perfused In Vitro Human iPSC-Derived Blood-Brain Barrier Faithfully Mimics Transferrin Receptor-Mediated Transcytosis of Therapeutic Antibodies.

Delivering biologics to elicit a therapeutic response in the central nervous system (CNS) remains challenging due to the presence of the blood-brain barrier (BBB). Receptor-mediated transcytosis is a strategy to improve brain exposure after systemic drug administration. The availability of a clinically relevant in vitro BBB model is crucial to investigate transcytosis pathways and to predict the penetration of biologics into the CNS.

Humanized zebrafish as a tractable tool for in vivo evaluation of pro-myelinating drugs.

Therapies that promote neuroprotection and axonal survival by enhancing myelin regeneration are an unmet need to prevent disability progression in multiple sclerosis. Numerous potentially beneficial compounds have originated from phenotypic screenings but failed in clinical trials. It is apparent that current cell- and animal-based disease models are poor predictors of positive treatment options, arguing for novel experimental approaches.

Ligand-Specific Allosteric Coupling Controls G-Protein-Coupled Receptor Signaling.

Allosteric coupling describes a reciprocal process whereby G-protein-coupled receptors (GPCRs) relay ligand-induced conformational changes from the extracellular binding pocket to the intracellular signaling surface. Therefore, GPCR activation is sensitive to both the type of extracellular ligand and intracellular signaling protein. We hypothesized that ligand-specific allosteric coupling may result in preferential (i.

Direct targeting of Gα and Gα oncoproteins in cancer cells.

Somatic gain-of-function mutations of and , which encode α subunits of heterotrimeric Gα proteins, occur in about 85% of cases of uveal melanoma (UM), the most common cancer of the adult eye. Molecular therapies to directly target these oncoproteins are lacking, and current treatment options rely on radiation, surgery, or inhibition of effector molecules downstream of these G proteins. A hallmark feature of oncogenic Gα proteins is their reduced intrinsic rate of hydrolysis of guanosine triphosphate (GTP), which results in their accumulation in the GTP-bound, active state.

Repurposing HAMI3379 to Block GPR17 and Promote Rodent and Human Oligodendrocyte Differentiation.

Identification of additional uses for existing drugs is a hot topic in drug discovery and a viable alternative to de novo drug development. HAMI3379 is known as an antagonist of the cysteinyl-leukotriene CysLT receptor, and was initially developed to treat cardiovascular and inflammatory disorders. In our study we identified HAMI3379 as an antagonist of the orphan G protein-coupled receptor GPR17.

Allosteric modulators targeting CNS muscarinic receptors.

Muscarinic acetylcholine receptors are G protein-coupled receptors (GPCRs) which are broadly expressed in the central nervous system (CNS) and other tissues in the periphery. They emerge as important drug targets for a number of diseases including Alzheimer's disease, Parkinson's disease, and schizophrenia. Muscarinic receptors are divided into five subtypes (M-M) of which M-M have been crystalized.

The Orphan Receptor GPR17 Is Unresponsive to Uracil Nucleotides and Cysteinyl Leukotrienes.

Pairing orphan G protein–coupled receptors (GPCRs) with their cognate endogenous ligands is expected to have a major impact on our understanding of GPCR biology. It follows that the reproducibility of orphan receptor ligand pairs should be of fundamental importance to guide meaningful investigations into the pharmacology and function of individual receptors. GPR17 is an orphan receptor characterized by some as a dualistic uracil nucleotide/cysteinyl leukotriene receptor and by others as inactive toward these stimuli altogether.

A New Molecular Mechanism To Engineer Protean Agonism at a G Protein-Coupled Receptor.

Protean agonists are of great pharmacological interest as their behavior may change in magnitude and direction depending on the constitutive activity of a receptor. Yet, this intriguing phenomenon has been poorly described and understood, due to the lack of stable experimental systems and design strategies. In this study, we overcome both limitations: First, we demonstrate that modulation of the ionic strength in a defined experimental set-up allows for analysis of G protein-coupled receptor activation in the absence and presence of a specific amount of spontaneous receptor activity using the muscarinic M acetylcholine receptor as a model.

Functional selectivity and dualsteric/bitopic GPCR targeting.

Functional selectivity provides a new avenue to selectively engage particular pathways of the pleiotropic signaling repertoire of a G protein-coupled receptor. First examples for signaling biased compounds at the angiotensin II receptor and the μ opioid receptor have progressed to clinical trials and are promising in regard to selective activation of signaling pathways that can be linked to beneficial clinical outcomes. Dualsteric/bitopic hybrid compounds which consist of at least two pharmacophores combined in one single ligand are more recent examples for functionally selective ligands.

The experimental power of FR900359 to study Gq-regulated biological processes.

Despite the discovery of heterotrimeric αβγ G proteins ∼25 years ago, their selective perturbation by cell-permeable inhibitors remains a fundamental challenge. Here we report that the plant-derived depsipeptide FR900359 (FR) is ideally suited to this task. Using a multifaceted approach we systematically characterize FR as a selective inhibitor of Gq/11/14 over all other mammalian Gα isoforms and elaborate its molecular mechanism of action.

Superagonism at G protein-coupled receptors and beyond.

Ligands targeting GPCRs can be categorized according to their intrinsic efficacy to trigger a specific, receptor-mediated response. A ligand endowed with the same level of efficacy as the endogenous agonist can be classified as a full agonist, whereas a compound that displays greater efficacy, that is, higher receptor signalling output than the endogenous agonist, can be called a superagonist. Subsequent to GPCR activation, an intracellular signalling cascade is set in motion, which may generate substantial amplification of the signal.

Rational design of partial agonists for the muscarinic m1 acetylcholine receptor.

Aiming to design partial agonists for a G-protein-coupled receptor based on dynamic ligand binding, we synthesized three different series of bipharmacophoric ligands composed of the orthosteric building blocks iperoxo and 1 linked to allosteric modulators (BQCA-derived compounds, BQCAd; TBPB-derived compound, TBPBd). Their interactions were studied with the human muscarinic acetylcholine M1-receptor (hM1) with respect to receptor binding and Gq-protein signaling. Results demonstrate that iperoxo/BQCAd (2, 3) and 1/BQCAd hybrids (4) act as M1 partial agonists, whereas 1/TBPBd hybrids (5) did not activate M1-receptors.

Dualsteric muscarinic antagonists--orthosteric binding pose controls allosteric subtype selectivity.

Bivalent ligands of G protein-coupled receptors have been shown to simultaneously either bind to two adjacent receptors or to bridge different parts of one receptor protein. Recently, we found that bivalent agonists of muscarinic receptors can simultaneously occupy both the orthosteric transmitter binding site and the allosteric vestibule of the receptor protein. Such dualsteric agonists display a certain extent of subtype selectivity, generate pathway-specific signaling, and in addition may allow for designed partial agonism.

A cell-permeable inhibitor to trap Gαq proteins in the empty pocket conformation.

In spite of the crucial role of heterotrimeric G proteins as molecular switches transmitting signals from G protein-coupled receptors, their selective manipulation with small molecule, cell-permeable inhibitors still remains an unmet challenge. Here, we report that the small molecule BIM-46187, previously classified as pan-G protein inhibitor, preferentially silences Gαq signaling in a cellular context-dependent manner. Investigations into its mode of action reveal that BIM traps Gαq in the empty pocket conformation by permitting GDP exit but interdicting GTP entry, a molecular mechanism not yet assigned to any other small molecule Gα inhibitor to date.

New insight into active muscarinic receptors with the novel radioagonist [³H]iperoxo.

Activation of G protein-coupled receptors involves major conformational changes of the receptor protein ranging from the extracellular transmitter binding site to the intracellular G protein binding surface. GPCRs such as the muscarinic acetylcholine receptors are commonly probed with radioantagonists rather than radioagonists due to better physicochemical stability, higher affinity, and indifference towards receptor coupling states of the former. Here we introduce tritiated iperoxo, a superagonist at muscarinic M₂ receptors with very high affinity.

Decoding signaling and function of the orphan G protein-coupled receptor GPR17 with a small-molecule agonist.

Replacement of the lost myelin sheath is a therapeutic goal for treating demyelinating diseases of the central nervous system (CNS), such as multiple sclerosis (MS). The G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor (GPCR) GPR17, which is phylogenetically closely related to receptors of the "purinergic cluster," has emerged as a modulator of CNS myelination. However, whether GPR17-mediated signaling positively or negatively regulates this critical process is unresolved.

Molecular alliance-from orthosteric and allosteric ligands to dualsteric/bitopic agonists at G protein coupled receptors.

Cell-membrane-spanning G protein coupled receptors (GPCRs) belong to the most important therapeutic target structures. Endogenous transmitters bind from the outer side of the membrane to the "orthosteric" binding site either deep in the binding pocket or at the extracellular N-terminal end of the receptor protein. Exogenous modulators that utilize a different, "allosteric", binding site unveil a pathway to receptor subtype-selectivity.

Agonists with supraphysiological efficacy at the muscarinic M2 ACh receptor.

Background And Purpose: Artificial agonists may have higher efficacy for receptor activation than the physiological agonist. Until now, such 'superagonism' has rarely been reported for GPCRs. Iperoxo is an extremely potent muscarinic receptor agonist.

The allosteric vestibule of a seven transmembrane helical receptor controls G-protein coupling.

Seven transmembrane helical receptors (7TMRs) modulate cell function via different types of G proteins, often in a ligand-specific manner. Class A 7TMRs harbour allosteric vestibules in the entrance of their ligand-binding cavities, which are in the focus of current drug discovery. However, their biological function remains enigmatic.

[Psammoma bodies in cytological vaginal smears in metastatic ovarian carcinoma].

The case of a 37-year old patient with ovarian cancer stage FIGO IV and vaginal metastasis is reported. The vaginal smear showed psammoma bodies, which are rarely found. The value of the diagnosis "psammoma bodies" is discussed, via a review of the literature.

[The value of colposcopy and portio biopsy in preventive examination].

133 patients attending the colposcopy-laser outpatient consultations were examined simultaneously by cytology, colposcopy and punch biopsy. A cone biopsy was taken 25 patients and one patient was hysterectomised later. A comparison between cytology and histology revealed 17.

[Attitude of patients to chorionic villi biopsy: motivation for the decision and perception].

56 patients with CVS were asked with a standardized questionnaire why they decided to undergo that surgical procedure and how they felt about it. 52 patients said, that their main motivation for CVS was the early diagnosis of a healthy baby. The low health risk of an early performed abruption in case of fetal abnormalities played a secondary role.

[Suspected abortion: morphologic aspects--value of histological examination of curettage specimen in suspected abortion and extra-uterine pregnancy].

Curettage specimens of 104 patients with clinically suspected abortion and unknown localization have been examined histologically. 50 patients with defined ectopic pregnancy, 51 patients with proved abortion and 50 patients with legal abortion had been used to compare with. In two cases syncytial cells could be proved histologically and by this an abortion could be verified.

[Cancer register problems--modified reporting law model for the improvement of data protection].

The author suggests creating a "Reporting Law Model with Peripheral Part Anonymisation" that preserves the advantages of the reporting law model which are internationally recognised in respect of reliability of registration, on the one hand, while on the other hand the general and individual requirements of sufficient protection of sensitive data are also taken care of. This is achieved by separating the personal data from the factual data at the reporting office level. These data are transmitted separately to the registration offices and their confidential files.