Research and Publications

**NEW**I have recently started a research stream to evaluate substance use education in pharmacy (and other health professional). We are working to develop educational content that will be used to explore opportunities for clinial harm reduction research.

My basic research lab is interested in the basic mechanisms of neuronal physiology as well as the molecular pharmacology of drugs that affect CNS function. Our research involves protein biochemical techniques, the use of primary cultured neurons and ex vivo hippocampal slice, fluorescent and confocal imaging, and electrophysiology. Specifically, we are interested in the role of RTKs in neuronal signaling. Many of these receptors are crucial for neuronal development, yet their role in the adult CNS remains poorly characterized. Although they are not targeted directly by therapeutic agents, these receptors have been implicated in the pathophysiology and treatment of several CNS disorders including Alzheimer’s disease, depression, and schizophrenia. Despite these linkages, there are several impediments to the clinical use of growth factors in CNS disease. Thus we are interested in novel mechanisms of RTK activation. RTKs are typically activated by growth factors: large, often dimeric proteins that bring two RTKs together, allowing them to activate each other via protein phosphorylation. However, many G protein-coupled receptors (GPCRs) are able to increase RTK expression or to activate RTKs through a process called transactivation. The mechanism(s) of GPCR transactivation of RTKs remain to fully elucidated but we have made significant contributions to understanding these pathways.

Ongoing Projects

RTK transactivation in the context of acute and chronic stress


Short vs. longterm 5-HT7 receptor regulation of RTKs and NMDA receptor activity: implications for neuroprotection

Acute (5 min) activation of 5-HT7 receptors increases NMDA-evoked currents in isolated hippocampal neurons. Interestingly, long-term (2-24 h) exposure to 5-HT7 receptor agonists downregulates the NR1 and NR2B NMDA receptor subunits and upregulates the PDGFβ receptor, a negative regulator of NMDA receptor signaling, and TrkB, often associated as a positive regulator of NMDA receptorsignaling. Thus, thereis aretemporally different regulatory pathways of NMDA receptors after 5-HT7 receptor activation. We have recently demonstrated that 5-HT7 receptor activation was able to protect hippocampal neurons against NMDA-induced excitotoxicity via its ability to increasePDGFβ receptorsignalling.


Receptor tyrosine kinase transactivation by GPCRs and the heterologous desensitization of transactivation

Application of 5-HT to primary cortical neurons or SH-SY5Y results in the transactivation of the PDGFβ receptor and TrkB. Many of the intracellular signaling steps in this pathway are similar to other transactivation pathways. However an interesting difference is that in this system compared to other transactivation pathways is that ERK1/2 phosphorylation is not dependent upon transactivation of the RTK. We recently demonstrated that such GPCR-RTK pathways can undergo a desensitization process.

Transactivated vs. ligand-activated RTKs

There is a growing number of examples of GPCR-RTK transactivation pathways. We are taking a step back and asking some fundamental questions about transactivation. Is a transactivated RTK the same as a ligand-activated RTK? Are the same tyrosine residues phosphorylated? Is the magnitude of transactivation sufficient to initiate signaling events (often the maximal increase in tyrosine phosphorylation is 2-3 fold, compared to up to 100 fold increases with ligands)?

Current Research Support

National Science and Engineering Research Council, Discovery Grant, 2013-2018, "Molecular mechanisms and physiological consequences of growth factor receptor transactivation in the central nervous system"

CFI-LOF and ORF, 2012, “Direct and indirect regulation of NMDA receptors by 5-HT7 receptor signaling”

Recent Publications

Kruk JS, Vasefi MS, Gondora N, Ahmed N, Heikkila JJ, Beazely MA. Fluoxetine-induced transactvation of the platelet-derived growth factor typeβ receptor reveals a novel heterologous desensitization process. Mol Cell Neurosci, accepted manuscript.

Samarajeewa S, Goldemann L, Khanderia C, Vasefi SM, Ahmed N, Gondora N, Mielke J, Beazely MA. 5-HT7 receptor activation promotes an increase in TrkB receptor expres-sion and phosphorylation. Front Behav Neurosci 2014;8:391. Special issue: “Further Understanding of Serotonin 7 Receptors’ Neuro-Psycho-Pharmacology”

Alqawlaq S, Sivak JM, Huzil TJ, Ivanova MV, Flanagan J, Beazely MA, Foldvari M. Preclinical development and ocular biodistribution of Gemini-DNA nanoparticles after intravitrieal and topical administration: towards non-invasive glaucoma gene therapy. Nanomedicine 2014 Epub June 3.

Kruk JS,Vasefi MS, Heikkila JJ, Beazely MA. Reactive oxygen species are required for 5-HT-induced transactivation of the neuronal platelet-derived growth factor and TrkB receptors, but not for ERK1/2 activation. PLoS One 2013;8:e77027.

Vasefi SM, Yang K, Li J,Kruk JS, Heikkila JJ, Jackson MF, MacDonald JF, Beazely MA. Acute 5-HT7 receptor activation increases NMDA-evoked currents and differentially alters NMDA receptor subunit phosphorylation and trafficking in hippocampal neurons. Mol Brain 2013;6:24.

Vasefi SM,Kruk JS, Heikkila JJ, Beazely MA. 5-HT7 receptor neuroprotection against NMDA- induced excitotoxicity is PDGFβ receptor-dependent. J Neurochem 2013;125:26-36.

Kruk JS,Vasefi SM,Liu H, Heikkila JJ, Beazely MA. 5-HT(1A) receptors transactivated the platelet-derived growth factor receptor type beta in neuronal cells. Cell Signal 2013;25:133-43.

Mohamed T, Yeung JCK,Vasefi MS, Beazely MA, Rao PN. Development and Evaluation of Multifunctional Agents for Potential Treatment of Alzheimer’s Disease: Application to a Pyrimidine-2,4-Diamine Template. Bioorg and Med Chem Lett 2012;22:4707-12.

Vasefi SM,Kruk JS,Liu H, Heikkila JJ, Beazely MA. Activation of 5-HT7 receptors increases neuronal platelet-derived growth factor beta receptor expression. Neurosci Lett 2012;511:65-9.

Peng F, Yao H, Bai X, Zhu X, Reiner BC, Beazely MA, Funa K, Xiong H, Buch S. Platelet- derived growth factor-mediated induction of the synaptic plasticity gene Arc/Arg3.1. J Biol Chem 2010;285:21615-24.

For full listclick here.

*underlined indicates Beazely lab member

Book Chapters, Review Articles, and other publications:

Kruk JS, Kouchmeshky A, Grimburg N, Rezkella M, Beazely MA. Transactivation of receptor tyrosine kinases by dopamine receptors. In: Neuromethods, Dopamine Receptor Tech-nologies. Tiberi M, ed.Humana Press 2014

MacDonald JF, Kotecha S, Jackson MF, Beazely MA. Chapter 4: Postsynaptic Excitatory Transmission. In:Molecular Pain. Zhuo M, ed. Higher Education Press, 2007.

MacDonald JF, Jackson MF, Beazely MA. Hippocampal Long-Term Synaptic Plasticity and Signal Amplification of NMDA Receptors. Critical Rev Neurobiol 2006;18:71-84.

MacDonald JF, Jackson MF, Beazely MA. G protein-Coupled Receptors Control NMDARs and Metaplasticity in the Hippocampus Review G Protein-Coupled Receptors. Biochim Biophys Acta 2007;1768:941-51.

Beazely MA, Watts VJ. Regulation of adenylate cyclases type 5 and 6: A progress report. Eur J Pharmacol. 2006;535(1-3):1-12.

Recent Posters and Presentations:

Poster, Beazely MA. Removing the barriers to managing both medical and illicit substance use in community practice settings: a thought experiment and educational tool development. Society for Neuroscience, Chicago IL, 2015.

Invited Lecture,“Heterologous desensitization of RTK transactivation” Discovery on Target Conference, Boston, MA, 2015

Invited Lecture,“A systematic approach to understanding GPCR transactivation of receptor tyrosine kinases” Department of Physiology and Pharmacology, Western University, London ON, 2014

Poster, Beazely MA,Liu H,Saffi G,Vasefi SM,Ahmed N,Gondora N. “Beta-amyloid inhibits PDGFβ receptor activation and prevents PDGF-BB-induced neuroprotection” Canadian Association for Neuroscience 2014, Montreal QE

Poster, Beazely MA,Kruk JS. “Serotonin transactivation of PDGFβ receptors results in a heterologous desensitization to subsequent transactivation stimuli”Experimental Biology 2013, Boston, MA, USA

Invited Lecture, “Expanded scopes of practice for pharmacists and pharmacy technicians” Ontario Health Human Resources Research Network Symposium (OHHRRN, with co-investigator Rishma Walji), Toronto ON, 2013

Invited Lecture,“Determining the physiological relevance of GPCR-induced growth factor receptor transactivation” Drug Safety and Effectiveness Cross-Disciplinary Training Program (DSECT, “tag-team” presentation with graduate student Azita Kouchmeshky), Hamilton ON, 2013

Poster,Kruk JS,Vasefi SM, Heikkila J, Beazely MA. “Fluoxetine-induced transactivation of the platelet-derived growth factor type β in serotonergic signaling reveals heterologous desensitization in neurons” Canadian Pharmacy Education and Research Conference 2013,Niagara-on-the-Lake, ON

Poster,Kruk JS,Vasefi SM, Beazely MA.“Fluoxetine-induced transactivation of the platelet-derived growth factor type β in serotonergic neurons” Southern Ontario Neuroscience Association Conference 2013, Wilfrid Laurier University, Waterloo, ON

Poster,Vasefi SM, Beazely MA.Regulation of NMDA receptors by the 5-HT7 receptor” Southern Ontario Neuroscience Association Conference 2013, Wilfrid Laurier University, Waterloo, ON

Poster,Kouchmeshky A,Saffi G, Beazely MA.“Determining the physiological relevance of GPCR-induced growth factor receptor transactivation” Southern Ontario Neuroscience Association Conference 2013, Wilfrid Laurier University, Waterloo, ON

Poster,Saffi G,Liu H,Kruk JS,Vasefi SM, Beazely MA. “Aβ42 prevents PDGF-β receptor Tyr1021 phosphorylation and reduces cell viability in presence of PDGF-BB” Southern Ontario Neuroscience Association Conference 2013, Wilfrid Laurier University, Waterloo, ON

Poster,Samarajeewa A,Kouchmeshky, A,Vasefi SM, Beazely MA. “Prospective intervention forglaucoma: 5-HT7 receptor activation increases TrkB expression and phosphorylation” Southern Ontario Neuroscience Association Conference 2013, Wilfrid Laurier University, Waterloo, ON

Poster,Vasefi SM, Beazely MA. “5-HT7 receptor-induced neuroprotection is PDGF receptor-dependent” Great Lakes GPCR Conference 2012, London, ON

Invited Lecture, “Policy analysis of scope of practice changes for pharmacists and optometrists and regulation of pharmacy technicians” OHHRRN Fireside Chat (online presentation and Q+A forum), 2012

Poster,Kruk JS, Beazely MA. “Monoamine transporter inhibitors can transactivate the platelet-derived growth factor receptor type beta in neuronal cells” Great Lakes GPCR Conference 2012, London ON

Poster,Vasefi SM, Beazely MA. “5-HT7 receptor neuroprotection against excitotoxicity in the hippocampus” Association of Faculties of Pharmacy in Canada, Annual Meeting 2012

Poster,Liu H, Beazely MA. “Platelet-derived growth factor (PDGF) neuroprotection against beta-amyloid induced neurotoxicity and beta-amyloid inhibition of PDGF receptor signaling”Drug Safety and Effectiveness Cross-Disciplinary Training Program Conference2012, Hamilton, ON

Michael Beazely 2016