11.1. 2016, Neurochemie

PhD project1:

Molecular mechanisms of signalling bias at muscarinic receptors.

Muscarinic acetylcholine receptors are G-protein coupled receptors (GPCRs) located in the plasma membrane of many cell types of various tissues. These receptors mediate extracellular to intracellular signalling. Alterations in signalling via muscarinic receptors play an important role in a variety of neurological and psychiatric disorders, e.g. Alzheimer's disease, schizophrenia, and also in other internal diseases, e.g. asthma and overactive bladder.

A biased agonist is a ligand which stabilizes a particular active conformation of a receptor, thus stimulating some responses but not others. Biased agonists might represent a novel and uniquely effective type of therapeutic agent with reduced side-effects. Several lines of evidence suggest that some muscarinic agonists although they bind with the same affinity to all subtypes of muscarinic receptor activate individual subtypes to different extent and display signalling bias. Understanding of the molecular mechanisms of signalling bias at muscarinic receptors may facilitate development of desired functionally-selective antagonists and agonists.

 

Candidate’s profile (requirements):

MD or MSc or equivalent degree in physiology, cellular biology, biochemistry, molecular biology or pharmacology. Practice at laboratory of biochemistry, pharmacology or molecular biology.

 

Relavant publications:

R.M. Eglen, Overview of muscarinic receptor subtypes, in: A.D. Fryer, Arthur Christopoulos, N.M. Nathanson (Eds.), Handb Exp Pharmacol, Springer 2012: pp. 3–28.

T. Kenakin, A. Christopoulos, Signalling bias in new drug discovery: detection, quantification and therapeutic impact, Nat Rev Drug Discov. 12 (2013) 205–216.

E. Šantrůčková, V. Doležal, E.E. El-Fakahany, J. Jakubík, Long-Term Activation upon Brief Exposure to Xanomleline Is Unique to M1 and M4 Subtypes of Muscarinic Acetylcholine Receptors, PLoS One. 9 (2014) e88910.

A. Randáková, E. Dolejší, V. Rudajev, P. Zimčík, V. Doležal, E.E. El-Fakahany, J. Jakubík, Classical and atypical agonists activate M1 muscarinic acetylcholine receptors through common mechanisms, Pharmacol Res. 97 (2015) 27–39.

 

Supervisor: Jan Jakubík PhD

 

PhD project 2: 

Molecular mechanisms of membrane cholesterol effects on function of muscarinic receptors.

Muscarinic acetylcholine receptors are G-protein coupled receptors (GPCRs) located in the plasma membrane of many cell types of various tissues. These receptors mediate extracellular to intracellular signalling. Alterations in signalling via muscarinic receptors play an important role in a variety of neurological and psychiatric disorders, e.g. Alzheimer's disease, schizophrenia, and also in other internal diseases, e.g. asthma and overactive bladder.

Cholesterol has been found to co-crystallize with a number of GPCRs.  Our current experiments show that membrane cholesterol specifically binds to muscarinc receptor and slows down their activation. Aim of the project is to delineate the molecular mechanisms of cholesterol action at muscarinic receptors and to identify putative differences among subtypes of muscarinic receptors

 

Candidate’s profile (requirements):

MD or MSc or equivalent degree in physiology, cellular biology, biochemistry, molecular biology or pharmacology. Practice at laboratory of biochemistry, pharmacology or molecular biology.

 

Relavant publications:

R.M. Eglen, Overview of muscarinic receptor subtypes, in: A.D. Fryer, Arthur Christopoulos, N.M. Nathanson (Eds.), Handb Exp Pharmacol, Springer 2012: pp. 3–28.

G. Gimpl, Interaction of G protein coupled receptors and cholesterol, Chem Phys Lipids. 199 (2016) 61–73.

P. Michal, E.E. El-Fakahany, V. Doležal, Changes in Membrane Cholesterol Differentially Influence Preferential and Non-preferential Signaling of the M1 and M3 Muscarinic Acetylcholine Receptors, Neurochem Res. 40 (2014) 2068–2077.

M. Manna, M. Niemelä, J. Tynkkynen, M. Javanainen, W. Kulig, D.J. Müller, T. Rog, I. Vattulainen, Mechanism of allosteric regulation of β2-adrenergic receptor by cholesterol, Elife. 5 (2016) 1–21.

 

Supervisor: Jan Jakubík PhD

 

PhD project 3: 

Cholinergic modulation of striatum-based behaviour.

The striatum is the main input nucleus of the basal ganglia, a complex structure controlling motor and executive functions, reward related processes and learning. The striatum is composed of GABAergic output neurons and two types of interneurons, cholinergic (CINs) and GABAergic. CINs, due to their rich axonal branching and semi-synchronized activity, have a large impact on striatal circuits. CINs can modulate activity of striatal output neurons and they control release of glutamate and dopamine through the nicotinic acetylcholine receptors (nAChRs) expressed by striatal projection terminals. While these mechanisms have been extensively studied, little is known about cholinergic activation of striatal GABAergic interneurons expressing alpha4beta2 nAChRs. Aim of the project is to determine how disruption of cholinergic activation of striatal GABAergic interneurons alters striatal signalling and striatum-based behaviour. To do that, we will develop a mouse model with deletion of the b2 nAChR subunit in striatal GABAergic interneurons and characterize this model with special focus on striatum-based behaviour and biochemical alterations in the striatum.

 

Candidate’s profile (requirements):

MD or MSc or equivalent degree in physiology, behavioural biology, biochemistry, molecular biology or pharmacology. Experience in animal handling. Practice at laboratory of behavioural biology, biochemistry, pharmacology or molecular biology.

 

Relevant publications:

Faust TW, Assous M, Tepper JM, Koos T.: Neostriatal GABAergic Interneurons Mediate Cholinergic Inhibition of Spiny Projection Neurons. J Neurosci. 2016, 36: 9505-11.
Rapanelli M, Frick LR, Xu M, Groman SM, Jindachomthong K, Tamamaki N, Tanahira C, Taylor JR, Pittenger C.: Targeted Interneuron Depletion in the Dorsal Striatum Produces Autism-like Behavioral Abnormalities in Male but Not Female Mice. Biol Psychiatry 2017, 82: 194-203.
Munoz-Manchado AB, Foldi C, Szydlowski S, Sjulson J, Farries M, Wilson C, Silberberg G, Hjerling-Leffler J.: Novel striatal GABAergic interneuron populations labeled in the 5HT3aEGFP mouse. Cereb Cortex 2016, 26: 96-105.  

Kljakic O, Janickova H, Prado VF, Prado MAM.: Cholinergic/glutamatergic co-transmission in striatal cholinergic interneurons: new mechanisms regulating striatal computation. J Neurochem. 2017, 142 Suppl. 2: 90-102. Review.

Janickova H, Prado VF, Prado MAM, El Mestikawy S, Bernard V.: Vesicular acetylcholine transporter (VAChT) over-expression induces major modifications of striatal cholinergic interneuron morphology and function. J Neurochem. 2017, doi: 10.1111/jnc.14105 (Epub ahead of print)

 

Supervisor: MUDr. Helena Janíčková, PhD