Journal articles
Stathakos P, Jiménez-Moreno N, Crompton LA, Nistor PA, Badger JL, Barbuti PA, Kerrigan TL, Randall AD, Caldwell MA, Lane JD, et al (2021). A monolayer hiPSC culture system for autophagy/mitophagy studies in human dopaminergic neurons.
Autophagy,
17(4), 855-871.
Abstract:
A monolayer hiPSC culture system for autophagy/mitophagy studies in human dopaminergic neurons.
Macroautophagy/autophagy cytoplasmic quality control pathways are required during neural development and are critical for the maintenance of functional neuronal populations in the adult brain. Robust evidence now exists that declining neuronal autophagy pathways contribute to human neurodegenerative diseases, including Parkinson disease (PD). Reliable and relevant human neuronal model systems are therefore needed to understand the biology of disease-vulnerable neural populations, to decipher the underlying causes of neurodegenerative disease, and to develop assays to test therapeutic interventions in vitro. Human induced pluripotent stem cell (hiPSC) neural model systems can meet this demand: they provide a renewable source of material for differentiation into regional neuronal sub-types for functional assays; they can be expanded to provide a platform for screening, and they can potentially be optimized for transplantation/neurorestorative therapy. So far, however, hiPSC differentiation protocols for the generation of ventral midbrain dopaminergic neurons (mDANs) - the predominant neuronal sub-type afflicted in PD - have been somewhat restricted by poor efficiency and/or suitability for functional and/or imaging-based in vitro assays. Here, we describe a reliable, monolayer differentiation protocol for the rapid and reproducible production of high numbers of mDANs from hiPSC in a format that is amenable for autophagy/mitophagy research. We characterize these cells with respect to neuronal differentiation and macroautophagy capability and describe qualitative and quantitative assays for the study of autophagy and mitophagy in these important cells.Abbreviations: AA: ascorbic acid; ATG: autophagy-related; BDNF: brain derived neurotrophic factor; CCCP: carbonyl cyanide m-chlorophenylhydrazone; dbcAMP: dibutyryl cAMP; DAN: dopaminergic neuron; DAPI: 4',6-diamidino-2-phenylindole; DAPT: N-[N-(3,5-difluorophenacetyl)-L-alanyl]-sphenylglycine; DLG4/PSD95: discs large MAGUK scaffold protein 4; DMEM: Dulbecco's modified eagle's medium; EB: embryoid body; ECAR: extracellular acidification rate; EGF: epidermal growth factor; FACS: fluorescence-activated cell sorting; FCCP: arbonyl cyanide p-triflouromethoxyphenylhydrazone; FGF: fibroblast growth factor; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GDNF: glia cell derived neurotrophic factor; hiPSC: human induced pluripotent stem cell; LAMP2A: lysosomal associated membrane protein 2A; LT-R: LysoTracker Red; MAP1LC3: microtubule associated protein 1 light chain 3; mDAN: midbrain dopaminergic neuron; MEF: mouse embryonic fibroblast; MT-GR: MitoTracker Green; MT-R: MitoTracker Red; NAS2: normal SNCA2; NEM: neuroprogenitor expansion media; NR4A2/NURR1: nuclear receptor subfamily group a member 2; OA: oligomycin and antimycin A; OCR: oxygen consumption rate; PD: Parkinson disease; SHH: sonic hedgehog signaling molecule; SNCA/α-synuclein: synuclein alpha; TH: tyrosine hydroxylase; VTN: vitronectin.
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Imm J, Pishva E, Ali M, Kerrigan TL, Jeffries A, Burrage J, Glaab E, Cope EL, Jones KM, Allen ND, et al (2021). Characterization of DNA Methylomic Signatures in Induced Pluripotent Stem Cells During Neuronal Differentiation.
Frontiers in Cell and Developmental Biology,
9Abstract:
Characterization of DNA Methylomic Signatures in Induced Pluripotent Stem Cells During Neuronal Differentiation
In development, differentiation from a pluripotent state results in global epigenetic changes, although the extent to which this occurs in induced pluripotent stem cell-based neuronal models has not been extensively characterized. In the present study, induced pluripotent stem cell colonies (33Qn1 line) were differentiated and collected at four time-points, with DNA methylation assessed using the Illumina Infinium Human Methylation EPIC BeadChip array. Dynamic changes in DNA methylation occurring during differentiation were investigated using a data-driven trajectory inference method. We identified a large number of Bonferroni-significant loci that showed progressive alterations in DNA methylation during neuronal differentiation. A gene–gene interaction network analysis identified 60 densely connected genes that were influential in the differentiation of neurons, with STAT3 being the gene with the highest connectivity.
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Thei L, Imm J, Kaisis E, Dallas ML, Kerrigan TL (2018). Microglia in Alzheimer's Disease: a Role for Ion Channels.
Front Neurosci,
12Abstract:
Microglia in Alzheimer's Disease: a Role for Ion Channels.
Alzheimer's disease is the most common form of dementia, it is estimated to affect over 40 million people worldwide. Classically, the disease has been characterized by the neuropathological hallmarks of aggregated extracellular amyloid-β and intracellular paired helical filaments of hyperphosphorylated tau. A wealth of evidence indicates a pivotal role for the innate immune system, such as microglia, and inflammation in the pathology of Alzheimer's disease. The over production and aggregation of Alzheimer's associated proteins results in chronic inflammation and disrupts microglial clearance of these depositions. Despite being non-excitable, microglia express a diverse array of ion channels which shape their physiological functions. In support of this, there is a growing body of evidence pointing to the involvement of microglial ion channels contributing to neurodegenerative diseases such as Alzheimer's disease. In this review, we discuss the evidence for an array of microglia ion channels and their importance in modulating microglial homeostasis and how this process could be disrupted in Alzheimer's disease. One promising avenue for assessing the role that microglia play in the initiation and progression of Alzheimer's disease is through using induced pluripotent stem cell derived microglia. Here, we examine what is already understood in terms of the molecular underpinnings of inflammation in Alzheimer's disease, and the utility that inducible pluripotent stem cell derived microglia may have to advance this knowledge. We outline the variability that occurs between the use of animal and human models with regards to the importance of microglial ion channels in generating a relevant functional model of brain inflammation. Overcoming these hurdles will be pivotal in order to develop new drug targets and progress our understanding of the pathological mechanisms involved in Alzheimer's disease.
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Imm J, Kerrigan TL, Jeffries A, Lunnon K (2017). Using induced pluripotent stem cells to explore genetic and epigenetic variation associated with Alzheimer's disease.
Epigenomics,
9(11), 1455-1468.
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Using induced pluripotent stem cells to explore genetic and epigenetic variation associated with Alzheimer's disease.
It is thought that both genetic and epigenetic variation play a role in Alzheimer's disease initiation and progression. With the advent of somatic cell reprogramming into induced pluripotent stem cells it is now possible to generate patient-derived cells that are able to more accurately model and recapitulate disease. Furthermore, by combining this with recent advances in (epi)genome editing technologies, it is possible to begin to examine the functional consequence of previously nominated genetic variants and infer epigenetic causality from recently identified epigenetic variants. In this review, we explore the role of genetic and epigenetic variation in Alzheimer's disease and how the functional relevance of nominated loci can be investigated using induced pluripotent stem cells and (epi)genome editing techniques.
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Tamagnini F, Novelia J, Kerrigan TL, Brown JT, Tsaneva-Atanasova KT, Randall AD (2015). Altered intrinsic excitability of hippocampal CA1 pyramidal neurons in aged PDAPP mice. Front. Cell. Neurosci., 9
Kerrigan TL, Brown JT, Randall AD (2014). Characterization of altered intrinsic excitability in hippocampal CA1 pyramidal cells of the Aβ-overproducing PDAPP mouse.
Neuropharmacology,
79(100), 515-524.
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Characterization of altered intrinsic excitability in hippocampal CA1 pyramidal cells of the Aβ-overproducing PDAPP mouse.
Transgenic mice that accumulate Aβ peptides in the CNS are commonly used to interrogate functional consequences of Alzheimer's disease-associated amyloidopathy. In addition to changes to synaptic function, there is also growing evidence that changes to intrinsic excitability of neurones can arise in these models of amyloidopathy. Furthermore, some of these alterations to intrinsic properties may occur relatively early within the age-related progression of experimental amyloidopathy. Here we report a detailed comparison between the intrinsic excitability properties of hippocampal CA1 pyramidal neurones in wild-type (WT) and PDAPP mice. The latter is a well-established model of Aβ accumulation which expresses human APP harbouring the Indiana (V717F) mutation. At the age employed in this study (9-10 months) CNS Abeta was elevated in PDAPP mice but significant plaque pathology was absent. PDAPP mice exhibited no differences in subthreshold intrinsic properties including resting potential, input resistance, membrane time constant and sag. When CA1 cells of PDAPP mice were given depolarizing stimuli of various amplitudes they initially fired at a higher frequency than WT cells. Commensurate with this, PDAPP cells exhibited a larger fast afterdepolarizing potential. PDAPP mice had narrower spikes but action potential threshold, rate of rise and peak were not different. Thus not all changes seen in our previous studies of amyloidopathy models were present in PDAPP mice; however, narrower spikes, larger ADPs and the propensity to fire at higher frequencies were consistent with our prior work and thus may represent robust, cross-model, indices of amyloidopathy. This article is part of a Special Issue entitled 'Neurodevelopment Disorder'.
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Kerrigan TL, Randall AD (2013). A new player in the "synaptopathy" of Alzheimer's disease - arc/arg 3.1.
Front Neurol,
4Abstract:
A new player in the "synaptopathy" of Alzheimer's disease - arc/arg 3.1.
Alzheimer's disease (AD) is increasingly referred to as a "synaptopathy." This moniker reflects the loss or damage of synapses that occurs as the disease progresses, which in turn produces functional degeneration of specific neuronal circuits and consequent aberrant activity in neural networks. Accumulating evidence supports the functional importance of the early-expression activity-regulated cytoskeletal (Arc) gene in regulating memory consolidation. Interestingly, AD patients express anomalously high levels of Arc protein. Arc physically associates with presenilin1, a pivotal protease for the generation of Amyloid β (Aβ) peptides. Arc expression itself is disrupted in the vicinity of Aβ oligomers and plaques. Such alterations result in the interruption of neuronal network integration in vivo. It is not clear what the impacts of these alterations are on the functional neurophysiology of transgenic mouse models of AD-associated amyloidopathy. Our group and others have described alterations to neuronal excitability and thus intrinsic firing within these transgenic mice models. This brief review will emphasize the rising role of Arc and its involvement in neurophysiological alterations of current AD models.
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Whitehead G, Jo J, Hogg EL, Piers T, Kim D-H, Seaton G, Seok H, Bru-Mercier G, Son GH, Regan P, et al (2013). Acute stress causes rapid synaptic insertion of Ca2+ -permeable AMPA receptors to facilitate long-term potentiation in the hippocampus.
Brain,
136(Pt 12), 3753-3765.
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Acute stress causes rapid synaptic insertion of Ca2+ -permeable AMPA receptors to facilitate long-term potentiation in the hippocampus.
The neuroendocrine response to episodes of acute stress is crucial for survival whereas the prolonged response to chronic stress can be detrimental. Learning and memory are particularly susceptible to stress with cognitive deficits being well characterized consequences of chronic stress. Although there is good evidence that acute stress can enhance cognitive performance, the mechanism(s) for this are unclear. We find that hippocampal slices, either prepared from rats following 30 min restraint stress or directly exposed to glucocorticoids, exhibit an N-methyl-d-aspartic acid receptor-independent form of long-term potentiation. We demonstrate that the mechanism involves an NMDA receptor and PKA-dependent insertion of Ca2+ -permeable AMPA receptors into synapses. These then trigger the additional NMDA receptor-independent form of LTP during high frequency stimulation.
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Crompton LA, Byrne ML, Taylor H, Kerrigan TL, Bru-Mercier G, Badger JL, Barbuti PA, Jo J, Tyler SJ, Allen SJ, et al (2013). Stepwise, non-adherent differentiation of human pluripotent stem cells to generate basal forebrain cholinergic neurons via hedgehog signaling.
Stem Cell Res,
11(3), 1206-1221.
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Stepwise, non-adherent differentiation of human pluripotent stem cells to generate basal forebrain cholinergic neurons via hedgehog signaling.
Basal forebrain cholinergic neurons (bfCNs) which provide innervation to the hippocampus and cortex, are required for memory and learning, and are primarily affected in Alzheimer's Disease (AD), resulting in related cognitive decline. Therefore generation of a source of bfCNs from human pluripotent stem cells (hPSCs) is crucial for in vitro disease modeling and development of novel AD therapies. In addition, for the advancement of regenerative approaches there is a requirement for an accurate developmental model to study the neurogenesis and survival of this population. Here we demonstrate the efficient production of bfCNs, using a novel embryoid body (EB) based non-adherent differentiation (NAdD) protocol. We establish a specific basal forebrain neural stem cell (NSC) phenotype via expression of the basal forebrain transcription factors NKX2.1 and LHX8, as well as the general forebrain marker FOXG1. We present evidence that this lineage is achieved via recapitulation of embryonic events, with induction of intrinsic hedgehog signaling, through the use of a 3D non-adherent differentiation system. This is the first example of hPSC-derived basal forebrain-like NSCs, which are scalable via self-renewal in prolonged culture. Furthermore upon terminal differentiation these basal forebrain-like NSCs generate high numbers of cholinergic neurons expressing the specific markers ChAT, VACht and ISL1. These hPSC-derived bfCNs possess characteristics that are crucial in a model to study AD related cholinergic neuronal loss in the basal forebrain. Examples are expression of the therapeutic target p75(NTR), the release of acetylcholine, and demonstration of a mature, and functional electrophysiological profile. In conclusion, this work provides a renewable source of human functional bfCNs applicable for studying AD specifically in the cholinergic system, and also provides a model of the key embryonic events in human bfCN development.
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Watt NT, Taylor DR, Kerrigan TL, Griffiths HH, Rushworth JV, Whitehouse IJ, Hooper NM (2012). Prion protein facilitates uptake of zinc into neuronal cells.
Nat Commun,
3Abstract:
Prion protein facilitates uptake of zinc into neuronal cells.
Zinc is released into the synaptic cleft upon exocytotic stimuli, although the mechanism for its reuptake into neurons is unresolved. Here we show that the cellular prion protein enhances the uptake of zinc into neuronal cells. This prion-protein-mediated zinc influx requires the octapeptide repeats and amino-terminal polybasic region in the prion protein, but not its endocytosis. Selective antagonists of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors block the prion protein-mediated zinc uptake, and the prion protein co-immunoprecipitates with both GluA1 and GluA2 AMPA receptor subunits. Zinc-sensitive intracellular tyrosine phosphatase activity is decreased in cells expressing prion protein and increased in the brains of prion-protein-null mice, providing evidence of a physiological consequence of this process. Prion protein-mediated zinc uptake is ablated in cells expressing familial associated mutants of the protein and in prion-infected cells. These data suggest that alterations in the cellular prion protein-mediated zinc uptake may contribute to neurodegeneration in prion and other neurodegenerative diseases.
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Kerrigan TL, Daniel J W, Regan PL, Cho K (2012). The role of neuronal calcium sensors in balancing synaptic plasticity and synaptic dysfunction.
Front Mol Neurosci,
5Abstract:
The role of neuronal calcium sensors in balancing synaptic plasticity and synaptic dysfunction.
Neuronal calcium sensors (NCS) readily bind calcium and undergo conformational changes enabling them to interact and regulate specific target molecules. These interactions lead to dynamic alterations in protein trafficking that significantly impact upon synaptic function. Emerging evidence suggests that NCS and alterations in Ca(2+) mobilization modulate glutamate receptor trafficking, subsequently determining the expression of different forms of synaptic plasticity. In this review, we aim to discuss the functional relevance of NCS in protein trafficking and their emerging role in synaptic plasticity. Their significance within the concept of "translational neuroscience" will also be highlighted, by assessing their potential as key molecules in neurodegeneration.
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Jo J, Whitcomb DJ, Olsen KM, Kerrigan TL, Lo S-C, Bru-Mercier G, Dickinson B, Scullion S, Sheng M, Collingridge G, et al (2011). Aβ(1-42) inhibition of LTP is mediated by a signaling pathway involving caspase-3, Akt1 and GSK-3β.
Nat Neurosci,
14(5), 545-547.
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Aβ(1-42) inhibition of LTP is mediated by a signaling pathway involving caspase-3, Akt1 and GSK-3β.
Amyloid-β(1-42) (Aβ) is thought to be a major mediator of the cognitive deficits in Alzheimer's disease. The ability of Aβ to inhibit hippocampal long-term potentiation provides a cellular correlate of this action, but the underlying molecular mechanism is only partially understood. We found that a signaling pathway involving caspase-3, Akt1 and glycogen synthase kinase-3β is an important mediator of this effect in rats and mice.
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Dallas ML, Boyle JP, Milligan CJ, Sayer R, Kerrigan TL, McKinstry C, Lu P, Mankouri J, Harris M, Scragg JL, et al (2011). Carbon monoxide protects against oxidant-induced apoptosis via inhibition of Kv2.1.
FASEB J,
25(5), 1519-1530.
Abstract:
Carbon monoxide protects against oxidant-induced apoptosis via inhibition of Kv2.1.
Oxidative stress induces neuronal apoptosis and is implicated in cerebral ischemia, head trauma, and age-related neurodegenerative diseases. An early step in this process is the loss of intracellular K(+) via K(+) channels, and evidence indicates that K(v)2.1 is of particular importance in this regard, being rapidly inserted into the plasma membrane in response to apoptotic stimuli. An additional feature of neuronal oxidative stress is the up-regulation of the inducible enzyme heme oxygenase-1 (HO-1), which catabolizes heme to generate biliverdin, Fe(2+), and carbon monoxide (CO). CO provides neuronal protection against stresses such as stroke and excitotoxicity, although the underlying mechanisms are not yet elucidated. Here, we demonstrate that CO reversibly inhibits K(v)2.1. Channel inhibition by CO involves reactive oxygen species and protein kinase G activity. Overexpression of K(v)2.1 in HEK293 cells increases their vulnerability to oxidant-induced apoptosis, and this is reversed by CO. In hippocampal neurons, CO selectively inhibits K(v)2.1, reverses the dramatic oxidant-induced increase in K(+) current density, and provides marked protection against oxidant-induced apoptosis. Our results provide a novel mechanism to account for the neuroprotective effects of CO against oxidative apoptosis, which has potential for therapeutic exploitation to provide neuronal protection in situations of oxidative stress.
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Kerrigan TL, Atkinson L, Peers C, Pearson HA (2008). Modulation of 'A'-type K+ current by rodent and human forms of amyloid beta protein.
Neuroreport,
19(8), 839-843.
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Modulation of 'A'-type K+ current by rodent and human forms of amyloid beta protein.
The Alzheimer's disease related peptide amyloid beta (Abeta) might have a physiological role in upregulating K channel currents in neurones. Earlier studies used the human form of Abeta1-40 on rat neurones. We sought to confirm our hypothesis by use of rat Abeta, which has no Alzheimer's association. In rat cerebellar granule neurones and HEK293 cells expressing Kv4.2 subunits, whole-cell patch clamp of K currents revealed that preincubation of cells with recombinant human or rat Abeta1-40 (10 nM for 24 h) significantly increased K channel current density. This was accompanied by increased mRNA levels for Kv4.2. These data indicate that rodent and human Abeta are effective in modulating K currents. The effectiveness of nonaggregating rat Abeta also strongly supports a physiological role for the peptide.
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