Molecular Pharmacology

Research Areas

• Molecular pharmacology
• Drug discovery
• Hypertension
• Computational chemistry

Research Overview 

Led by Dr Nicola J Smith, the Molecular Pharmacology Laboratory studies a family of receptors called G protein-coupled receptors. Receptors are proteins that convey changes in a cell’s environment so that it can respond in an appropriate manner. For example, during the ‘fight or flight’ response, an adrenergic receptor on the heart will respond to increased levels of the circulating hormone, adrenaline, to increase cardiac output. Because they respond to minute-to-minute changes in the cell’s external environment, they are subject to an exquisite set of controls in both space and time. For this and many other reasons, this family of proteins is the most successful source of current drug targets (e.g. treatments of high blood pressure, psychiatric disorders, pain, clotting disorders) and provide exciting potential targets for the treatment of obesity, type 2 diabetes, pulmonary hypertension and many more.

The specific focus of the Molecular Pharmacology Laboratory is the discovery of new drugs for receptors where the partner hormone is still to be found. These are called ‘orphan’ G protein-coupled receptors and make up the majority of all receptors in the family. The team combines in vitro drug screens and computational approaches to drug discovery with animal models of cardiovascular disease to further our understanding of new ways in which we can target cardiovascular disease, particularly high blood pressure. 

There are 3 key projects underway in the Molecular Pharmacology Laboratory, led by Dr Nicola J Smith:

1. Novel signalling paradigm for the orphan G protein-coupled receptor, GPR37L1

Without an endogenous ligand, it is very difficult to decipher the role an orphan GPCR plays in the body. We have used the intrinsic capacity of a receptor to signal in the absence of a ligand, so-called ‘constitutive activity’, to show that the orphan GPCR, GPR37L1, signals via Gαs to increase cAMP in the cell. Using this approach, we discovered an entirely new way for a GPCR to signal: GPR37L1 is constitutively active only if the N-terminus is present (Coleman, Ngo et al. Sci Signalling 2016). We continue to explore this new mechanism of signal transduction using some of the following techniques commonly employed in our laboratory: mammalian cell culture, heterologous expression systems, protein purification, site-directed mutagenesis, confocal microscopy, bioluminescence resonance energy transfer, luciferase reporter assays, yeast culture and primary cell and tissue slice cultures.

2. Cardiovascular role of GPR37L1

The orphan GPCR, GPR37L1, was first identified from a screen of heart failure individuals as being down-regulated in disease. We have generated a series of genetically modified mice that have global, inducible and/or cell type-specific deletion of GPR37L1 and are examining their cardiovascular phenotype both under normal physiological conditions and after cardiovascular stress. Some of the techniques we use in the laboratory are small animal surgeries (TAC banding, micromanometry), cardiac morphometry, RNA extraction and real time PCR, western blotting, immunohistochemistry and ex vivo cerebellar slice cultures.

3. Computational identification of surrogate ligands for orphan GPCRs

The Smith Lab’s work is based upon the hypothesis that we can ‘unlock’ orphan GPCRs by using rational and high throughput computational methods to identify surrogate ligands for each receptor. Upon identifying a surrogate ligand, the orphan then becomes amenable to many pharmacological and physiological approaches. The principal goal of the Smith Laboratory is to establish a pipeline of drug discovery for cardiovascular disease, leveraging an innovative computational method (GPCR-CoINPocket), developed by the Smith Lab, to identify surrogate and then ultimately high affinity ligands for orphan GPCRs. This program combines both surrogate ligand and virtual library screening for novel chemical species with site-directed mutagenesis and molecular modelling of orphan binding sites to make key discoveries about GPCR ligand:receptor interactions. 

Laboratory Members

Meghna Sobti, Senior Research Officer 

James Coleman, PhD student

Margaret Mouat, PhD student

Sean So, PhD student

Collaborators

Prof Ruben Abagyan & Dr Irina Kufareva, UCSD

Prof Thomas Preiss, John Curtin School of Medical Research

Prof Cheol-Hee Kim, Chungnam National University

Prof Marcello Leopoldo, University of Bari

A/Prof Nigel Turner, University of New South Wales

Prof Andrew Allen, University of Melbourne

1. Ngo, T., Ilatovskiy, A.V., Stewart, A.G., Coleman, J.L.J., McRobb, F.M., Riek, R.P., Graham, R.M., Abagyan, R., Kufareva, I.*, Smith, N.J.* (2016) Orphan receptor ligand discovery by pickpocketing pharmacological neighbours. Nature Chemical Biology, 13(2), 235-242. [Research highlight in Nat Rev Drug Discov: Kingwell, K., 16(2) p86, 2017].

2. Coleman, J.L.J.*, Ngo, T.*, Schmidt, J., Mrad, N., Liew, C-K., Jones, N.M., Graham, R.M., Smith, N.J.** (2016) Metalloprotease cleavage of the N terminus of the orphan G protein-coupled receptor GPR37L1 reduces its constitutive activity. Science Signaling, 9(423)ra36. [with accompanying editorial: Gough, N.R., Sci Signal 9 eg6 (2016)]

3. Soetanto R., Hynes C.J., Patel H., Humphreys D.T., Evers M., Duan G.W., Parker B.J., Archer S.K., Clancy J.L., Graham R.M., Beilharz T., Smith N.J., Preiss T. (2016) Role of alternative mRNA 3’ end cleavage and polyadenylation in cardiomyocyte hypertrophy, Biochimica et Biophysica Acta (BBA): Gene Regulatory Mechanisms, 1859(5):744-756. 

4. Coleman, J.L., Brennan, K., Ngo, T., Balaji, P., Graham, R.M.*, Smith, N.J.* (2015) Rapid knockout and reporter mouse line generation and breeding colony establishment using EUCOMM conditional-ready embryonic stem cells: A case study. Frontiers in Endocrinology, June 2015, Vol 6, article 106.      

5. Ngo T., Coleman J.L., Smith N.J.* (2015) Using constitutive activity to define appropriate high-throughput screening assays for orphan G protein-coupled receptors. Methods Mol Biol. 1272:91-106.

6. Coleman, J.L.J.*, Ngo, T., Smith, N.J.* (2017) The G Protein-Coupled Receptor N-terminus and Receptor Signalling: N-tering a new era. Cellular Signalling, in press.

7. Ngo, T., Kufareva, I., Coleman, J.L., Graham, R.M., Abagyan, R., Smith, N.J.* (2016) Identifying ligands at orphan GPCRs: current status using structure-based approaches. British Journal of Pharmacology, 173(20):2934-2951. 

8. Smith, N.J.* Drug discovery opportunities at endothelin B receptor-related orphan G protein-coupled receptors, GPR37 and GPR37L1. (2015) Frontiers in Pharmacology, 6(275).