Austen Milnerwood, PhD
Austen Milnerwood鈥檚 research centers on cell biological, electrophysiological, and optical investigation of neural development, connectivity, transmission and plasticity. Below are examples of the lab themes.
Early pathophysiology of adult-onset degeneration
The world鈥檚 population is aging. By 2025, half of the population may be over 60, and 2% will have Alzheimer鈥檚 or Parkinson鈥檚 disease. There is a pressing societal, and financial, need to learn more about, and to better treat, late-onset neurodegenerative disease. Our projects include behavior and in vivo recording in rodents, electrophysiology and cell biology in acute brain slices, primary neuronal co-cultures, and patient stem cell-derived neurons. Working out how neuronal function goes awry early in disease states can help to intervene and possibly to prevent the onset or progression of degenerative processes.
A strong theme in the lab emerged from studying proteins harbouring gene variants linked to Parkinson鈥檚 disease, in other words, gene signatures transmitted down the family line that are highly predictive for developing PD. There are several proteins that cause 鈥渇amilial PD,鈥� e.g. LRRK2, VPS35 and synuclein. The Milnerwood lab is finding that these proteins are involved in the same cellular functions in neurons, which regulate synaptic function, and are influenced by immune signalling. By learning more about what these proteins are supposed to do, and what goes wrong with disease-linked gene variants, the Milnerwood lab hopes to work out common neuronal dysfunction of many forms of parkinsonism, and help develop appropriate treatments.
Synucleinopathy & LRRK2. 3-week in vitro neurons (dendrites and cell bodies shown in green) were exposed to alpha-synuclein fibrils, which causes aberrant phosphorylation and aggregation of endogenous mouse alpha synuclein (red). This happens in the cell body of some neurons (nuclei in blue, arrowhead), but first and more abundantly in neuronal axons (open arrowheads). The presence of these axonal aggregates is associated with axon degeneration and is likely a key initial step in synucleinopathies such as Parkinson鈥檚 and Lewy Disease. Neurons of LRRK2 Parkinson鈥檚 disease knock-in mice were harder hit, and those from LRRK2 knock-out mice were resistant to this, suggesting LRRK2 silencing could be therapeutically useful for PD. Modified from (click for paper).听
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Dopamine release, PD mice, & LRRK2 inhibition. Striatal dopamine release is electrically stimulated and recorded by ultra-high-speed imaging of dLight biosensor in living brain slices from mice. VPS35 Parkinson鈥檚 disease knock-in mice (VKI) have elevated dopamine release, which is reduced by 2h LRRK2 inhibition of slices. This suggests LRRK2 silencing could be therapeutically useful for PD. Modified from (click for paper).
Synaptic connectivity and plasticity
Synapses form and stabilize during development to form hard-wired pathways between specialized nuclei. But 鈥榟ard-wired鈥� pathways must retain the capacity to change for acquisition of new abilities and higher cognitive processes. This capacity, 鈥榮ynaptic plasticity鈥�, is thought to be the substrate for the formation, storage, and processing of information in the brain. Much is known of plasticity mechanisms, especially those underlying Long-Term Potentiation (LTP) and Depression (LTD), in the hippocampus. However, the interactions of age, sex, and immune status are still areas of intense research activity. In addition to the hippocampus, we investigate synaptic transmission and plasticity in the striatum; the gateway to the basal ganglia. The basal ganglia are a group of subcortical nuclei engaged in action selection for motor learning, emotional responses, skill acquisition, goal-directed, and habitual behavior. These abilities require organismal experience; therefore, striatal plasticity must occur in development, throughout adolescence, and well into adulthood. How LTP & LTD operate in the striatum, and how they are influenced by sex and maturation, is relatively poorly described. We use electrophysiology & optical recording to examine glutamate, acetylcholine, and dopamine function in plasticity processes of developing circuits in cultures, and developing and adult brains. In animals we examine the important role of sex during maturation and ageing.
Synaptic plasticity in complex circuits. Striatal synaptic plasticity can be studied in neuron co-cultures, where glutamate neuron effects on other cell types, such as striatal Drd1 GABAergic projection neurons (red or red and blue filled neuron for morphological assessment) can be examined in isolation from dopamine and other neuromodulators. Rapid, activity-dependent plasticity of striatal neuron dendritic spines and AMPA receptor clusters can be induced. Growth and pruning of dendritic protrusions is an active process, requiring glutamate receptor activity in striatal projection neurons. NMDA receptor activation is sufficient to drive glutamatergic structural plasticity in SPNs, in the absence of dopamine or other neuromodulators. Modified from (click for paper).
Personalized Medicine for Bipolar Disorder
Although psychiatric conditions such as bipolar disorder (BD) affect a great many individuals and families, we still have a poor understanding of the underlying biology of these conditions. There do exist some highly effective treatments, but we fundamentally don鈥檛 understand how they work. Many of the most effective treatments work very well for some patients but not at all for others, even in cases where the clinical circumstances are virtually identical. In bipolar disorder, 30% of patients respond well to lithium and are effectively cured, yet other patients do not respond at all.
Cell and animal models are very helpful when manipulating genes identified as casual to disease. While there is strong evidence that BD is genetic component, mutations in single genes have not been found. In collaboration with Professors Guy Rouleau (麻豆色情片) and Martin Alda (Dalhousie), a group effort led by lead scientist Dr Anouar Khayachi, has focussed on reprogramming cells from patient blood samples into iPSCs (induced pluripotent stem cells), which we then differentiate into neurons to interrogate the underlying neurobiological basis of BD. By comparing groups of patients with excellent medical history, we can investigate the patients鈥� response to specific treatments, to that of their neurons in a dish i.e., watch what treatment does in the neurons of people who respond well to treatment in comparison it to what it does (and doesn鈥檛 do) in neurons of patients with the same condition who do not respond.
This allows us to identify the biological basis of effective treatments, by working out what is happening in the neurons of people who have a positive response to a drug. Knowing this meant we could try reproduce this same positive response with other drugs, all in a dish, without subjecting patients to drugs that won鈥檛 work for them. In this way, we hope to provide new effective treatments for psychiatric patients based on reproducible science, with foundations in human neuronal biology.
Human neuron circuits and neuropsychiatric disease. Blood samples are taken from patients and control volunteers at clinics and used to make stem cells. Stem cells can be transformed into neural progenitor cells (top left) and then neurons in connected networks (top right). We measure activity of the whole network by imaging calcium / voltage dyes and optogenetic indicators, in comparison to recordings from individual neurons using whole-cell patch clamp electrodes (bottom left). Differences in electrical activity (action potential firing 鈥� bottom right) are detected in patient neural networks, which also respond differently to the drugs that worked in the source patients. Modified from (click for paper).
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Some Lab Photos
Kamesh*, Kadgien*, Kuhlmann*, Coady*, A. Pietrantonio*, Cousineau*, Khayachi*, Jurado-Santos, Hurley, Barron, Parsons & Milnerwood*. (2025). Emergent glutamate & dopamine dysfunction in VPS35(D620N) knock-in mice and rapid reversal by LRRK2 inhibition. Nature Parkinson's Disease.
Nguyen, Collier, Ignatenko, Morin, Goyon, Janer, Tiefensee-Ribeiro*, Milnerwood*, Huang, Desjardins & McBride. (2025). Mitochondrial Anchored Protein Ligase MAPL is an inflammatory rheostat that regulates pyroptotic cell death. Nature Cell Biology.
Pei, Oliveira, Recinto, Kazanova, Queiroz-Junior, Li, Couto, Westfall, Fahmy, Ribeiro*, King, Milnerwood*, Desjardins, Thanabalasuriar, Stratton & Gruenheid. (2025). LRRK2 G2019S mutation incites increased cell-intrinsic neutrophil effector functions and intestinal inflammation in a model of infectious colitis. Nature Parkinson's Disease.
Khayachi*, Abuzgaya*, Liu, Jiao, Dejgaard, Schorova, Kamesh*, He, Cousineau*, Pietrantonio*, Farhangdoost, Castonguay, Chaumette, Alda, Rouleau & Milnerwood*. (2024). Akt and AMPK activators rescue hyperexcitability in neurons from patients with bipolar disorder. Lancet eBiomedicine.
Jones-Tabah, He, Karpilovsky, Senkevich, Deyab, Pietrantonio, Goiran, Cousineau*, Nikanorova, Goldsmith, del Cid Pellitero, Chen, Luo, You, Abdian, Ahmad, Ruskey, Asayesh, Spiegelman, Fahn, Waters, Monchi, Dauvilliers, Dupr茅, Miliukhina, Timofeeva, Emelyanov, Pchelina, Greenbaum, Hassin-Baer, Alcalay, Milnerwood*, Durcan, Gan-Or & Fon (2024). The Parkinson's disease risk gene cathepsin B promotes fibrillar alpha-synuclein clearance, lysosomal function and glucocerebrosidase activity in dopaminergic neurons. Molecular Neurodegeneration.
Noel, Madranges, Gothi茅, Ewald, Milnerwood*, Kennedy & Scott. (2024). Maternal gastrointestinal nematode infection alters hippocampal neuroimmunity, promotes synaptic plasticity, and improves resistance to direct infection in offspring. Science Reports.
Bu, Follett, Tatarnikov, Wall, Guenther, Deng, Wimsatt, Milnerwood*, Moehle, Khoshbouei & Farrer. (2023). Inhibition of LRRK2 kinase activity rescues deficits in striatal dopamine dynamics in VPS35 p.D620N knock-in mice. Nature Parkinson's Disease.
Clement, Al-Alwan, Glasgow, Stolow, Ding, Quevedo-Melo*, Khayachi*, Liu, Hellmund, Haag, Milnerwood*, Gru虉tter & Kennedy. (2022). Dendritic Polyglycerol Amine: An Enhanced Substrate to Support Long-Term Neural Cell Culture. ASN Neuro.
Kuhlmann*, Volladolid*, Quesada-Ramirez*, Farrer & Milnerwood. (2021). Chronic and Acute Manipulation of Cortical Glutamate Transmission Induces Structural and Synaptic Changes in Co-cultured Striatal Neurons. Front Cell Neurosci.
Khayachi*, Ase, Liao, Kamesh*, Kuhlmann*, Schorova, Chaumette, Dion, Alda, S茅gu茅la, Rouleau & Milnerwood. (2021). Chronic lithium treatment alters the excitatory/ inhibitory balance of synaptic networks and reduces mGluR5-PKC signalling in mouse cortical neurons. J Psychiatry Neurosci.
Kadgien*, Kamesh*, Milnerwood*. (2021). Endosomal traffic and glutamate synapse activity are increased in VPS35 D620Nmutant knock-in mouse neurons, and resistant to LRRK2 kinase inhibition. Molecular Brain.
Singh, Khayachi*, Milnerwood* & DeMarco. (2020). Quantitative Profiling of Synuclein Species: Application to Transgenic Mouse Models of Parkinson's Disease. J Parkinsons Dis.
MacIsaac*, Quevedo-Melo*, Zhang*, Volta*, Farrer & Milnerwood *. (2020). Neuron autonomous susceptibility to induced synuclein aggregation is exacerbated by endogenous Lrrk2 mutations and ameliorated by Lrrk2 genetic knock-out. Brain Communications.
Kuhlmann* & Milnerwood *. (2020). A critical LRRK at the synapse? The neurobiological function & pathophysiological dysfunction of LRRK2. Front. Mol. Neurosci.
Volpicelli-Daley LA, Abdelmotilib H, Liu Z, Stoyka L, Daher JP,听Milnerwood听AJ, Unni VK, Hirst WD, Yue Z, Zhao HT, Fraser K, Kennedy RE, West AB.(2016)听G2019S-LRRK2 Expression Augments 伪-Synuclein Sequestration into Inclusions in Neurons.听J Neurosci.听
Volta M., Cataldi, S., Beccano-Kelly D.A., Munsie L.N., Tatarnikov I., Chou P., Bergeron S., Mitchell E., Lim R., Khinda, J.,听Lloret A., Bennett C.F., Paradiso C., Morari M., Farrer M.J. &听Milnerwood听A.J. (2015)听Chronic and acute LRRK2 silencing has no long-term behavioral effects, whereas wild-type and mutant LRRK2 overexpression induce motor and cognitive deficits and altered regulation of dopamine release.听Parkin. & Rel. dis.听
Volta M,听Milnerwood听AJ, Farrer MJ. (2015)听Insights from late-onset familial parkinsonism on the pathogenesis of idiopathic Parkinson's disease.听Lancet Neurol.听
Beccano-Kelly D.A., Volta M., Munsie L.N., Paschall S. A., Tatarnikov I., Co K., Chou P., Cao L.P., Bergeron S., Mitchell E., Han H., Melrose H.L., Tapia L., Raymond L.A., Farrer M.J. &听Milnerwood听A.J. (2015)听LRRK2 overexpression alters presynaptic glutamatergic plasticity, striatal dopamine tone, postsynaptic signal transduction, behavioral activity and long-term memory.听Hum Mol Gen.
Munsie L.N.,听Milnerwood听A.J.,听Seibler, P.听Beccano-Kelly D.A.,听Tatarnikov I.T.,听Kindah, J.,听Volta M.,听Kadgien C., Cao L.P., Tapia L. Klein C.听& Farrer M.J. (2015)听Retromer-dependent neurotransmitter receptor trafficking to synapses is altered by the Parkinson鈥檚 Disease VPS35 mutation p.D620N.听Hum Mol Gen.听
Beccano-Kelly D.A., Kuhlmann, N., Tatarnikov I., Volta M., Munsie L.N., Chou P., Cao L.P., Han H., Tapia L.,Farrer M.J. &听Milnerwood听A.J.听(2014)听Synaptic function is modulated by LRRK2 and glutamate release is increased in cortical neurons of G2019S LRRK2 knock-in mice.听Front. Cell. Neurosci.听
Brigidi G.S., Sun Y.,听Beccano-Kelly D.A., Pitman K., Borgland S.L.,听Milnerwood听A.J.听& Bamji S.X. Delta-catenin Palmitoylation is Essential for Activity-dependent Enhancements of Synapse Structure and Efficacy听(2014).听Nat Neurosci.听
Milnerwood听A. J., Parsons M., Young F., Singaraja, R.,听Volta M.,听Bergeron S., Hayden, M.R. & Raymond, L. A. (2013) Cognitive deficits and severe disruption of synaptic transmission and plasticity in HIP14 palmitoyl transferase knock-out mice.听PNAS听
Milnerwood听A.J., *Kaufman A.M., Sepers M., Gladding C.M., Fan, J., Coquinco, A., Zhang L.Y., Wang L., Qoi J., Lee H., Cynader, M. & Raymond L.A. (2012) Mitigation of augmented extrasynaptic NMDAR signaling and apoptosis in cortico-striatal co-cultures from Huntington鈥檚 disease mice.Neurobiol Dis.听
Kaufman A.M., *Milnerwood听A.J., Sepers M., Coquinco A., She K., Wang L., Lee H., Craig A.M., Cynader M. & Raymond L.A. (2012) Opposing roles of synaptic and extrasynaptic NMDA receptor signaling in striatal and cortical neurons.听J. Neurosci.听
Petkau T., Neal S.J.,听Milnerwood听A. J., Mew A., Hill A.M., Orban P., Gregg J., Lu H., Feldman H.H., Mackenzie I.R.A., Raymond L.A. & Leavitt B.R. (2012). Synaptic dysfunction in progranulin-deficient mice.听Neurobiol.Dis.
Tapia L.,听Milnerwood听A. J., Guo A., Mills F., Yoshida E., Vasuta O.C, Mackenzie I., Raymond, L. A., Cynader M., Jia W., Bamji S.X. (2011).听PGRN Deficiency Decreases Neural Connectivity But Enhances Synaptic Transmission at Individual Synapses.听J. Neurosci.听
Raymond LA, Andr茅 VM, Cepeda C, Gladding CM,听Milnerwood听AJ, Levine MS. (2011)听Pathophysiology of Huntington's disease: time-dependent alterations in synaptic and receptor function.听Neuroscience.听
Milnerwood听A. J.听, Gladding C. M., Pouladi M. A., Kaufman A.M., Hines R. M., Boyd听 J., Ko R.W.Y., Vasuta O. C., Graham R. K., Hayden M. R., Murphy T. H. & Raymond L. A. (2010). Early increase in extrasynaptic NMDA receptor signalling and expression contributes to phenotype onset in Huntington's disease mice.听Neuron
Milnerwood听A. J.听& Raymond L. A. (2010). Early Synaptic Pathophysiology in Neurodegeneration: Insights from Huntington鈥檚 disease.听Trends in Neurosciences听
Milnerwood听A. J.听& Raymond, L. A. (2007). Corticostriatal Synaptic Function in Mouse Models of Huntington's Disease: Early Effects of Huntingtin Repeat Length and Protein Load.听J. Physiol.听
Cummings D. M.,听Milnerwood听A. J., Dall茅rac G.M., Vatsavayai S. C., Hirst M. C. & Murphy, K. P. (2007). Abnormal cortical synaptic plasticity in mice transgenic for human Huntington's disease mutation.听Brain. Res. Bull.
Milnerwood听A. J., Cummings D. M., Dall茅rac G.M., Brown J. Y., Vatsavayai S. C., Hirst M. C., Rezaie P. & Murphy, K. P. (2006). Early development of aberrant synaptic plasticity in a mouse model of Huntington鈥檚 disease.听Hum. Mol. Gen.
