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Tony K.Y. Lim, Ph.D.

RNA Therapeutics, Neuroscience, Pharmacology and Immunology

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I am a scientist working at the intersection of RNA therapeutics, neuroscience, pharmacology, and immunology. My research focuses on creating self-amplifying RNA for safe and effective gene therapy that avoids harmful cell damage or triggering unwanted immune responses. This technology allows for long-lasting but reversible production of therapeutic proteins. With experience in studying pain and neuroinflammation—and skills in techniques such as self-amplifying RNA engineering, image-based microplate assays, video-based analysis of animal behaviour, and 2-photon microscopy—I aim to develop new treatments for neurological diseases.

Research
RESEARCH
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Gene therapy introduces genetic material into cells to help them produce therapeutic proteins that can restore or improve their function. Two main approaches currently dominate the field: mRNA therapy and viral gene therapy. mRNA therapy is effective for short-term protein expression, typically lasting a few days, whereas viral gene therapy offers long-term expression, sometimes for years or a lifetime. However, viral gene therapy has significant drawbacks, including risks of genomic damage that could lead to cancer, immune responses against the viral vector, limitations on the size of the genetic material it can deliver, and the inability to reverse the treatment if needed. Currently, there is no middle-ground therapy that combines the safety of mRNA with the durability of viral gene therapy. Self-amplifying RNA (saRNA) fills this gap by replicating itself inside cells, enabling prolonged protein production. This makes saRNA a promising candidate for therapies requiring intermediate-duration gene expression.

 

Despite its potential, using saRNA for gene therapy presents a key challenge: cells perceive RNA replication as a sign of viral infection. In response, they activate antiviral pathways that limit protein production, trigger inflammation, and induce programmed cell death. These responses restrict therapeutic protein production and cause tissue damage. My research addresses this issue by engineering saRNA to include proteins that suppress the cell’s ability to detect RNA replication and inhibit the associated immune pathways. With these proteins encoded in the saRNA, cells no longer perceive it as a threat, allowing therapeutic protein production without triggering inflammation or cell death. This adaptation makes saRNA suitable for gene therapy applications.​

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A unique feature of this approach is its reversibility. A small molecule inhibitor can prevent the saRNA from replicating, effectively halting its activity. This adds an important layer of safety and control, enabling the therapy to be turned off if adverse effects occur or if the therapy is no longer needed. It also facilitates the testing of new therapies by allowing fine-tuned control over their duration.

 

I have validated this system in cell culture experiments using fibroblast-like synoviocytes, which are cells that line the inside of joints and play critical roles in joint health and inflammation. My next goal is to optimize this platform for use in living organisms and expand its application to other cell types, such as neurons and immune cells. I believe this work has the potential to broaden the gene therapy toolbox and lead to new treatments for chronic pain, neuroinflammation, and aging.

EXPERTISE
EXPERTISE
  • Self amplifying RNA engineering

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Design of self-amplifying RNA constructs that inhibit diverse double-stranded RNA sensing and inflammatory signaling pathways using proteins expressed via cap-independent translation.

Learn more about this approach for transient gene therapy here:

http://biorxiv.org/content/10.1101/2024.09.24.614636

  • Microplate assay development and image-based analysis

BioTracker

EGFP

mScarlet3

Mock Transfection

Native saRNA

E3

E3-NSs-L*

moxBFP

srIκBα

srIκBα-Smad7-SOCS1

animation g1_2.gif

Development of a microplate assay for longitudinal monitoring of self-amplifying RNA translational control and cell number. (BioTracker = cell number, EGFP = cap-independent saRNA expression, mScarlet3 = cap-dependent saRNA expression)

This assay uses the Odyssey M plate imager. Spectral unmixing software for EGFP and mScarlet3 was coded by Dr. Larissa Ferguson and can be found here:

https://github.com/lariferg/spectral_unmixing

  • 2-photon intravital microscopy

10-neurophagy

Microglial cells phagocytosing neurons (neurophagy) in the developing brain. Timestamp=HH:MM

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Microglial cell (red) trogocytosing a pH-stable GFP-labelled axon (green). The colocalization of green and red is shown as white.

04-laser_injury.gif

Microglial cells (red) responding to a laser irradiation injury. Timestamp=HH:MM

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Microglial cells (red) extending processes to contact axons (green). Timestamp=HH:MM

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Left: Microglial cells (red) surveil the brain in the presence of an eGFP-labelled axon (green).

Right: Tracking of the microglial cells on the left panel in 3D.

Find out more about this work by checking out the article, published in eLife: https://elifesciences.org/articles/62167

  • Behavioural assay development and video analysis

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Simultaneous presentation of looming stimuli and recording of behavioural responses using Python.

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Automated tracking of a microglia-depleted tadpole making an escape response to bright looming stimuli.

  • CAD design and 3D printing

During the COVID-19 pandemic, nasopharyngeal swabs were in short supply. With a team that included 3D printing hobbyists, medical doctors, and bioengineers, we designed and developed a nasopharyngeal swab that could be made using low-cost FDM 3D printers, making it ideal for manufacturing in low resource settings.

  • Bioinformatics

Fig 3 cyspresso v2-2.png

CysPresso, a tool that utilizes machine learning of deep-learning protein representations to predict the compatibility of therapeutic peptides for use in gene therapy.

This software was developed by Sébastien Ouellet.

Code is available at: https://github.com/Zebreu/cyspresso

​

Try it out yourself here:

https://colab.research.google.com/github/Zebreu/cyspresso/blob/main/CysPresso.ipynb​

PUBLICATIONS
PUBLICATIONS
Researching and Writing

Peer-reviewed publications

 

Ouellet S, Ferguson L, Lau AZ, Lim TK. “CysPresso: a classification model utilizing deep learning protein representations to predict recombinant expression of cysteine-dense peptides.” BMC Bioinformatics, 21(1):200, 2023.

​

Lim TK, Ruthazer ES. “Microglial trogocytosis and the complement system regulate axonal pruning in vivo.” eLife, 10:e62167, 2021.


Solek CM, Farooqi N, Verly M, Lim TK, Ruthazer ES. “Maternal immune activation and neurodevelopmental disorders.” Dev Dyn, 247(4):588-619, 2018.

​

Lim TK, Anderson KM, Hari P, Di Falco M, Reihsen TE, Wilcox GL, Belani KG, LaBoissiere S, Pinto MR, Beebe DS, Kehl L, Stone LS. “Evidence for a role of nerve injury in painful intervertebral disc degeneration: A cross-sectional proteomic analysis of human cerebrospinal fluid.” J Pain, 18(10):1253-69, 2017.

​

Lim TK, Rone MB, Lee SH, Antel JP, Zhang J. “Mitochondrial and bioenergetic dysfunction in trauma-induced painful peripheral neuropathy.” Mol Pain, 11(1):58-67, 2015.

​

Lim TK, Shi XQ, Johnson J, Rone MB, Antel JP, David S, Zhang J. “Peripheral nerve injury induces persistent vascular dysfunction and endoneurial hypoxia, contributing to the genesis of neuropathic pain.” J Neurosci, 35(8):3346-59, 2015.

​

Zhang J, Echeverry S, Lim TK, Lee SH, Shi XQ, Huang H. “Can modulating inflammatory response be a good therapeutic strategy for treating neuropathic pain?” Curr Pharm Des, 21(7):831-9, 2014.

​

Lim TK, Shi XQ, Martin HC, Huang H, Luheshi G, Rivest S, Zhang J. “Blood-nerve barrier dysfunction contributes to the generation of neuropathic pain and allows targeting of injured nerves for pain relief.” Pain, 155(5):954-67, 2014.

​

Symons FJ, Wolff JJ, Stone LS, Lim TK, Bodfish JW. “Salivary biomarkers of HPA access and autonomic activity in adults with intellectual disability with and without stereotyped and self-injurious behaviour disorders.” J Neurodev Disord, 3(2):144-51, 2011.

​

Shi XQ*, Lim TK*, Lee S, Zhao YQ, Zhang J. “Statins alleviate experimental nerve-injury induced neuropathic pain.” Pain. 152(5):1033-43, 2011. (*co-first author)

​

Lim TK, MacLeod BA, Ries CR, Schwarz SK. “The quaternary lidocaine derivative, QX-314, produces long-lasting local anesthesia in animal models in vivo.” Anesthesiology, 107(2):305-11, 2007.

​

Book chapters


Echeverry S, Lee SH, Lim TK, Zhang J. “Contribution of inflammation to chronic pain triggered by nerve injury.” Basic Principles of Peripheral Nerve Disorders, Intech, 2012.
 

AWARDS & FELLOWSHIPS
AWARDS
Trophies

Awards

 

2023        Next Pharma Phenomenon team pitching competition, Department of                                    Pharmacology, University of Cambridge

2018        Best Poster Award, EMBO Workshop: Microglia 2018
2015        1st Place Basic Science Poster Award, McGill Pain Day
2014        2nd Place Basic Science Poster Award, McGill Pain Day
2014        Oral Presentation Open Prize, McGill Anesthesia Research Day
2013        Poster Award, International Brain Barriers Society
2013        1st Place Oral Presentation, CIHR Neuroinflammation Training Program
2011        3rd Place Poster Presentation, CIHR Neuroinflammation Training Program
2011        Best Basic Science Poster Award, McGill Pain Day
2006        Esther R. Anderson Memorial Prize, UBC Department of Pharmacology

Fellowships

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2022-2024

 

​2017–2020

​​​2016–2017

​​​2012–2014

​​​2009–2012

​​​2006

Marie Skłodowska-Curie Actions European Postdoctoral Fellowship (UKRI Guarantee)

CIHR Postdoctoral Fellowship

​McLaughlin McGill Faculty of Medicine Fellowship

​The Edwards Foundation PhD Studentship in Pain Research 

​CIHR Frederick Banting and Charles Best Doctoral Fellowship

​McGill Graduate Studies Fellowship
 

PRESENTATIONS
PRESENTATIONS
Presentation

Selected oral presentations

​​​

​“CysPresso: Predicting cysteine-dense peptide expression utilizing deep learning protein
representations.” PEGS Protein Engineering & Cell TherapySummit. Boston, MA. May 2024. (*Presented by co-author)
​

​​

​“Poster Highlight: Long-lasting expression of transgenes in mouse primary fibroblast-like
synoviocytes with self-amplifying RNA.” PEGS Protein Engineering & Cell Therapy
Summit. Boston, MA. May 2023.

​

“Microglial trogocytosis and the complement system regulate axonal pruning in vivo.” Canadian Neurophotonics Platform: Neuro Light Lunch Seminar Series, Virtual seminar, Jul 2020.

 

In vivo imaging of microglial-mediated synaptic pruning in the Xenopus laevis retinotectal circuit and modulation by the complement system.” Xenopus Gene Editing Workshop, Woods Hole, MA, Oct 2019.

 

In vivo imaging of microglial-mediated synaptic pruning in the developing retinotectal system.” Neuron-Glia Seminar Series, Montreal, Canada, Jun 2018.

 

“Do microglia eat synapses? An investigation by 2-photon live imaging.” University of Tokyo seminar, Tokyo, Japan, Mar 2018.

 

“Do microglia eat synapses? An investigation by 2-photon live imaging.” Kyoto University iCeMS seminar, Kyoto, Japan, Mar 2018.

 

“Do microglia eat synapses? An investigation by 2-photon live imaging.” Osaka University Frontier Bioscience Seminar, Osaka, Japan, Mar 2018.

 

“Do microglia eat synapses? Seeing is believing.” BRaIN Boost Symposium, Montreal, Canada, Feb 2018.

 

“The role of hypoxia in the generation of neuropathic pain.” Anesthesia Research Day, Montreal, Canada, May 2014.

 

“The vascular basis of neuropathic pain.” Quebec Network of Junior Pain Investigators, Montreal, Canada, Jul 2013.

 

“The vascular basis of neuropathic pain.” Integrated Program in Neuroscience Retreat, Montreal, Canada, Jun 2013

 

“A vascular hypothesis for neuropathic pain.” CIHR Neuroinflammation Training Program Symposium, Montreal, Canada, 2013.

RESEARCH EXPERIENCE
EXPERIENCE
Test Tubes
2022–2024
Research Associate

Engineered self-amplifying RNA constructs for non-immunostimulatory, sustained, reversible
transgene expression in fibroblast-like synoviocytes.

University of Cambridge

Cambridge, United Kingdom

Lab of Prof. Ewan St. John Smith

  • Engineered self-amplifying RNA constructs for non-immunostimulatory, sustained, reversible transgene expression in fibroblast-like synoviocytes.​​

2021–2022
Independent Scientist

CysPresso: a classification model utilizing deep learning protein representations to predict recombinant expression of cysteine-dense peptides

Unaffiliated

Vancouver, Canada

  • Led a bioinformatics project utilizing machine learning to predict the recombinant expression of cysteine-dense peptides in mammalian cells.​​

2016–2020

Postdoctoral Scholar

The role of microglial trogocytosis and the complement system in axonal pruning

The Montreal Neurological institute

Montreal, Canada

Lab of Dr Edward S. Ruthazer

  • Conducted in vivo studies using 2-photon microscopy to visualize microglial-mediated axonal
    pruning in Xenopus laevis.

  • Discovered an endogenous synapse-associated molecule that inhibits axonal pruning and engineered a synapse-associated fusion protein that enhances axonal pruning.

  • Developed a novel behavioral assay integrating programming, 3D printing, and computer vision for assessing visuomotor function.​​

2009–2015

Doctoral  Student

The role of vascular dysfunction in neuropathic pain

McGill University

Montreal, Canada

Lab of Dr Ji Zhang

  • Investigated the response of peripheral nerve vasculature to nerve injury, focusing on endoneurial microvascular dysfunction, hypoxia, and metabolic disturbances.

  • Discovered three different mechanisms to target analgesics to injured peripheral nerves.​

2007–2008

Master's Student

Evidence for a role of nerve injury in painful intervertebral disc degeneration: a cross-sectional proteomic analysis of human cerebrospinal fluid

McGill University

Montreal, Canada

Lab of Dr Laura S. Stone

  • Uncovered biomarkers that distinguish painful and asymptomatic phenotypes of degenerative disc disease in human cerebrospinal fluid using proteomics.

  • Uncovered biomarkers in the saliva of adults with self-injurious behaviour.

2006

Undergraduate Summer Research Project

The Quaternary Lidocaine Derivative, QX-314, Produces Long-lasting Local Anesthesia in Animal Models In Vivo

University of British Columbia

Vancouver, Canada

Labs of Dr Bernard A. MacLeod & Stephan K.W. Schwarz

  • Investigated the in vivo local anesthetic properties of the quaternary ammonium lidocaine derivative, QX-314.

2005-2006

Honour's Thesis Student

2005

Co-op Intern

2004

Co-op Intern

Summary of the discovery and development of RSD-921: From molecule to man

University of British Columbia

Vancouver, Canada

Lab of Dr Michael J.A. Walker

  • Summarized the discovery and development of RSD-921, a novel anti-arrhythmic.

​

Conventional and semi-high throughput electrophysiology of HCN ion channels

Johnson & Johnson Research & Development

La Jolla, San Diego, USA

Pain and Related Disorders Group

  • Performed conventional and high-throughput patch clamp electrophysiology on TRPV1, HCN, and hERG ion channels in primary rat dorsal root ganglion neurons and HEK293 cells.

​

Development of a clinically relevant rodent of allergic rhinitis

University of British Columbia

Vancouver, Canada

Supervisor: Michael J.A. Walker

  • Contributed to developing a guinea pig model of allergic rhinitis, facilitating in vivo drug screening.​

EDUCATION
EDUCATION
Circular Library
2009–2015

Doctor of Philosophy (PhD), Integrated Program in Neuroscience

2006–2008

Master of Science (MSc), Pharmacology & Therapeutics

2001–2006

Bachelor of Science (Hons), 

Pharmacology & Therapeutics

McGill University

Thesis: The role of vascular dysfunction in neuropathic pain

McGill University

Thesis: Proteomic analysis of human cerebrospinal fluid from patients with painful and non-painful degenerative disc disease

The University of British Columbia

Thesis: A summary of the discovery and development of RSD-921, a novel anti-arrhythmic

TEACHING
TEACHING & MENTORING
Chalkboard Drawings

Teaching

2023 - 2024

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2023 - 2024

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2023 - 2024

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2022 - 2023

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2022 - 2023

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2022 - 2023

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2019

Cambridge "supervisions" (small group tutorials)
Pharmacology NST Part IB
​

Laboratory practical demonstrator

Pharmacology NST Part IB

Laboratory practical demonstrator

Mechanisms of Drug Action MedST/VetST IB​

Cambridge "supervisions" (small group tutorials)
Pharmacology NST Part II
​

Cambridge "supervisions" (small group tutorials)
Pharmacology NST Part IB
​

Laboratory practical demonstrator

Mechanisms of Drug Action MedST/VetST IB​

Workshop: "Practical 3D printing for Life Scientists"
McGill University, Montreal Neurological Institute

  • Organized, created and presented a 3 hour workshop on 3D printing

Student supervision

2024

 

2020​

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2014​

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2013​

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2012​

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2011

T. Abdul (Undergraduate student, University of Cambridge)

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J. Ho (Undergraduate student, McGill University)

​

J. Jang (Undergraduate student, McGill University)

​

J. Lou (Undergraduate student, University of Alberta)

​

J. Johnson (Undergraduate student, University of Alberta)

​

H. Martin (Undergraduate student, Memorial University)

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