Biology subjects

White, A. R.

Publications and source records attributed to White, A. R..

17 recordsLinked to original sources

bioRxiv2026

Alzheimer's Disease-Associated Proteomic Changes in Olfactory Stem Cells Show Pathway-Level Transcriptomic Overlap

Alzheimer's disease (AD) is a progressive, neurodegenerative disorder and the leading cause of dementia worldwide. Although recent therapeutic advances have provided some disease-modifying potential, there is currently no curative treatment for AD, highlighting the need for improved disease models and early biomarkers. Olfactory mucosal stem cells, which can be expanded in vitro as olfactory neurosphere-derived (ONS) cells, represent a promising source for biomarker discovery because olfactory tissue is more accessible than central nervous system tissue and has been reported to exhibit AD-related pathological changes. In this study, we used subcellular fractionation-based proteomics, reconstructed bulk proteomics and integrated transcriptomic-proteomic analyses to characterise alterations in ONS cells derived from healthy control, mild cognitive impairment (MCI) and AD individuals. Fraction-specific proteomics identified cytoplasmic and nuclear-enriched protein abundance changes, including alterations in proteins and pathways associated with cytoskeletal organisation, RNA processing, intracellular trafficking, autophagy and mitochondrial/metabolic processes. Reduced LC3B abundance in cytoplasmic AD ONS cells was supported by western blot analysis, although LC3B abundance alone does not indicate altered autophagic flux. Reconstructed bulk proteomics identified 40 FDR-significant proteins in AD compared with HC, defining an AD-associated protein signature enriched for extracellular matrix, cytoskeletal, organelle-associated and RNA-processing pathways. Despite proteomic enrichment of mitochondrial and metabolic pathways, Seahorse Mito Stress Test analysis did not identify significant group-level differences in mitochondrial respiration. Integrated transcriptomic-proteomic analysis revealed partial RNA-protein concordance and pathway-level overlap across disease-associated processes. Together, these findings support the use of patient-derived ONS cells as a model for investigating AD- and MCI-associated molecular changes and highlight protein signatures for further validation.

neuroscience↗

bioRxiv2026

Computational drug repurposing identifies N-acetylglucosamine as a potential therapeutic compound for CLN3 Batten disease

Batten disease, also known as neuronal ceroid lipofuscinoses, is one of the most common causes of childhood dementia. It is characterized by the accumulation of lipofuscin in lysosomes, leading to loss of brain cell function, onset of dementia-like symptoms, vision loss and seizures and has extremely limited treatment options. Here, we performed computational drug repurposing analysis to identify existing compounds that may target Batten disease risk genes. A total of 81 candidate compounds were identified, 6 of which were selected based on clinical tractability for downstream testing in Batten disease (CLN3) iPSC-derived models. After confirming disease phenotype and drug candidate safety, CLN3 brain cell cultures treated with and without drug candidates underwent bulk RNA-seq to identify drug responses. One of the candidate drugs N-acetylglucosamine (GlcNAc) significantly upregulated Batten disease risk gene CLN5 expression and several other lysosomal markers within CLN3 brain cells, and modulated several pathways implicated in lysosomal storage disorders. Importantly, GlcNAc significantly reduced lipofuscin burden in both CLN3 iPSC-derived neurons and astrocytes, supporting its investigation as an additional therapy for Batten disease.

neuroscience↗

bioRxiv2025

CD300LG is a receptor for triglyceride-rich lipoproteins that facilitates postprandial lipid clearance

Circulating triglycerides are principally transported by triglyceride-rich lipoprotein particles (TRLs) including very-low-density-lipoproteins (VLDL) and chylomicrons and require the activity of lipoprotein lipase for appropriate lipid processing and cellular uptake. Despite known genetic links between CD300LG variants and altered lipid profiles, the functional role of CD300LG in lipid metabolism remains unclear. In this study, we identify CD300LG as a crucial receptor for TRLs. Human genetic analyses reveal that reduced CD300LG protein levels are causally linked with CAD risk and increased number, diameter, and TAG concentration of TRLs. In mice, CD300LG deficiency results in postprandial hypertriglyceridemia independent of changes in VLDL secretion, intestinal lipid absorption, or lipoprotein lipase activity. Mechanistically, CD300LG acts as a receptor for TRLs through a direct interaction with ApoA4 to facilitate TRL clearance at the microvascular endothelium. These findings elucidate new functions for both CD300LG and ApoA4 and advance our general understanding of triglyceride metabolism.

physiology↗

bioRxiv2024

Impact of wildfire smoke and diesel exhaust on inflammatory response in aging human microglia

BackgroundAir pollution, particularly from Diesel Exhaust Particles (DEP) and Wildfire Smoke (WFS), is increasingly recognised as a significant driver of neuroinflammation linked to brain diseases. However, the role of microglia in mediating these neuroinflammatory responses remains poorly understood. This study aimed to investigate the effects of air pollution on monocyte-derived microglia-like cells (MDMi) from both young (< 40 years of age), and (older > 60 years of age) healthy individuals, focusing on immune response, cytokine secretion, nitrosative stress, and phagocytic activity. ResultsOur study demonstrated that DEP and WFS extract (WFSE) significantly upregulated expression of the oxidative stress marker, heme-oxygenase-1 (HO-1) in MDMi after 24 hr, with levels normalising by 96 hr, indicating a transient oxidative stress response. Both DEP and WFSE elicited distinct inflammatory cytokine profiles. DEP induced a rapid response, increasing TNF-, IL-6, IL-23, and IL-33 within 2 hr in young MDMi and 24 hr in aged MDMi. In contrast, WFSE triggered a delayed but sustained inflammatory response, with TNF-, IFN-{gamma}, IL-23, and IL-33 levels persisting at 96 hr in aged MDMi, highlighting an age-related vulnerability to air pollutant-induced inflammation. Both pollutants activated p38, ERK, and NF-{kappa}B pathways, with p38 activity resolving by 96 hours and ERK activation persisting, reflecting their distinct roles in cellular stress and inflammation. NF-{kappa}B p65 nuclear translocation, observed at 24 hours, highlighted its critical role in cytokine release and inflammation following exposure to DEP and WFSE. This is the first report of NF-{kappa}B activation in human microglia exposed to air pollutants. ConclusionsThese results highlight the distinct and potentially harmful effects of DEP and WFSE on immune and inflammatory responses in MDMi, particularly in ageing populations, with significant implications for brain health. DEP triggers acute oxidative stress and inflammatory responses, while WFSE induces more prolonged effects, especially in aged microglia. Both pollutants activate the MAPK and NF-{kappa}B pathways and exhibit unique cytokine profiles, underscoring their overlapping yet distinct mechanisms of action. These findings advance our understanding of air pollutant-induced neuroinflammation and its contribution to neurodegeneration, providing a foundation for developing targeted interventions to mitigate the neurotoxic effects of air pollution.

cell biology↗

bioRxiv2024

A patient-derived amyotrophic lateral sclerosis blood-brain barrier cell model reveals focused ultrasound-mediated anti-TDP-43 antibody delivery.

BackgroundAmyotrophic lateral sclerosis (ALS) is a rapidly progressing neurodegenerative disorder with minimally effective treatment options. An important hurdle in ALS drug development is the non-invasive therapeutic access to the motor cortex currently limited by the presence of the blood-brain barrier (BBB). Focused ultrasound and microbubble (FUS+MB) treatment is an emerging technology that was successfully used in ALS patients to temporarily open the cortical BBB. However, FUS+MB-mediated drug delivery across ALS patients BBB has not yet been reported. Similarly, the effects of FUS+MB on human ALS BBB cells remain unexplored. MethodsHere we established the first FUS+MB-compatible, fully-human ALS patient-cell-derived BBB model based on induced brain endothelial-like cells (iBECs) to study anti-TDP-43 antibody delivery and FUS+MB bioeffects in vitro. ResultsGenerated ALS iBECs recapitulated disease-specific hallmarks of BBB pathology, including changes to BBB integrity, permeability and TDP-43 proteinopathy. Our results also identified differences between sporadic ALS and familial (C9orf72 expansion carrying) ALS iBECs reflecting patient heterogeneity associated with disease subgroups. Studies in these models revealed successful ALS iBEC monolayer opening in vitro with a lack of adverse cellular effects of FUS+MB. This was accompanied by the molecular bioeffects of FUS+MB in ALS iBECs including changes in expression of tight and adherens junction markers, and drug transporter and inflammatory mediators, with sporadic and C9orf72 ALS iBECs generating transient specific responses. Additionally, we demonstrated an effective increase in the delivery of anti-TDP-43 antibody with FUS+MB in C9orf72 (2.7-fold) and sporadic (1.9-fold) ALS iBECs providing the first proof-of-concept evidence that FUS+MB can be used to enhance the permeability of large molecule therapeutics across the BBB in a human ALS in vitro model. ConclusionsTogether, our study describes the first characterisation of cellular and molecular responses of ALS iBECs to FUS+MB and provides a fully-human platform for FUS+MB-mediated drug delivery screening on an ALS BBB in vitro model.

neuroscience↗

bioRxiv2023

Increased tau expression in the APOE4 blood-brain barrier model is associated with reduced anti-tau therapeutic antibody delivery in vitro.

Tau protein is a critical driver of neurodegeneration and an important drug target in Alzheimers disease (AD). Tau-specific immunotherapy has emerged as a promising treatment strategy for AD, however the therapeutic efficacy of anti-tau antibodies may be limited by their insufficient delivery across the blood-brain barrier (BBB). The apolipoprotein E4 allele (APOE4) is the strongest genetic risk factor for sporadic AD and is known to influence tau-mediated neurodegeneration. Interestingly, both tau and APOE4 have been implicated in the cerebrovascular pathology observed in AD. Yet, the crosstalk between APOE4 and tau at the level of the BBB and its consequences for anti-tau immunotherapeutics delivery, remain poorly understood. Here, we utilised APOE3- and APOE4-carrying human iPSC-derived induced brain endothelial-like cells (iBECs) as a sporadic AD BBB model, determined the levels of endogenous tau in iBECs, and explored the transport of two novel monoclonal anti-tau antibodies, RNF5 and RN2N, across the in vitro barrier. Our results demonstrate that MAPT gene transcription, tau protein levels and tau phosphorylation are increased in iBECs in an APOE4-related manner and are associated with reduced iBEC monolayer integrity and increased permeability to biologically inert fluorescent tracers. Additionally, elevated levels of intracellular tau in APOE4 cells were accompanied by the reduced passive permeability of therapeutic anti-tau antibodies through the APOE4 iBEC monolayer, which could be improved by the application of focused ultrasound and microbubble drug-delivery technology. Together, our study illustrates a new role for APOE4 and tau in human iBECs with potential implications for BBB dysfunction and anti-tau therapeutic antibody delivery.

cell biology↗

bioRxiv2023

A patient-derived blood-brain barrier model for screening copper bis(thiosemicarbazone) complexes as potential therapeutics in Alzheimer's disease

Alzheimers disease (AD) is the most prevalent cause of dementia characterised by progressive cognitive decline. Addressing neuroinflammation represents a promising therapeutic avenue to treat AD, however, the development of effective anti-neuroinflammatory compounds is often hindered by their limited blood-brain barrier (BBB) permeability. Consequently, there is an urgent need for accurate, preclinical AD patient-specific BBB models to facilitate the early identification of immunomodulatory drugs capable of efficiently crossing human AD BBB. This study presents a unique approach to BBB drug permeability screening as it utilises the familial AD patient-derived induced brain endothelial-like cells (iBEC)-based model, which exhibits increased disease relevance and serves as an improved BBB drug permeability assessment tool when compared to traditionally employed in vitro models. To demonstrate its utility as a small molecule drug candidate screening platform, we investigated the effects of CuII(atsm) and a library of novel metal bis(thiosemicarbazone) complexes - a class of compounds exhibiting anti-neuroinflammatory therapeutic potential in neurodegenerative disorders. By evaluating the toxicity, cellular accumulation and permeability of those compounds in the AD patient-derived iBEC, we have identified CuII(dtsm) as an emerging drug candidate with enhanced transport across the AD BBB. Furthermore, we have developed a multiplex approach where AD patient-derived iBEC were combined with immune modulators TNF and IFN{gamma} to establish an in vitro model representing the characteristic neuroinflammatory phenotype at the patients BBB. Here we observed that treatment with CuII(dtsm) not only reduced the expression of proinflammatory cytokine genes but also reversed the detrimental effects of TNF and IFN{psi} on the integrity and function of the AD iBEC monolayer. This suggests a novel pathway through which copper bis(thiosemicarbazone) complexes may exert neurotherapeutic effects in AD by mitigating BBB neuroinflammation and related BBB integrity impairment. Together, the presented model provides an effective and easily scalable in vitro BBB platform for screening AD drug candidates. Its improved translational potential makes it a valuable tool for advancing the development of metal-based compounds aimed at modulating neuroinflammation in AD. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=199 HEIGHT=200 SRC="FIGDIR/small/554047v1_ufig1.gif" ALT="Figure 1"> View larger version (71K): org.highwire.dtl.DTLVardef@1d949b5org.highwire.dtl.DTLVardef@7629ccorg.highwire.dtl.DTLVardef@1b2125dorg.highwire.dtl.DTLVardef@1d3cde1_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2023

A novel patient-derived cellular platform for validating microglia-targeted therapeutics for Alzheimer's disease

The scarcity of effective biomarkers and therapeutic strategies for predicting disease onset and progression in Alzheimers disease (AD) is a major challenge to improve much-needed therapeutic outcomes. Conventional drug discovery approaches have been unsuccessful in providing efficient interventions due to their one-size-fits-all nature. As an alternative, personalised drug development holds promise to pre-select responders and identify suitable drug efficacy indicators. In this study, we established a preclinical drug testing strategy by assessing the efficacy of anti-inflammatory drugs in 2D and 3D in vitro models of monocyte-derived microglia-like cells (MDMi) derived from AD and mild cognitive impairment (MCI) patients, and matched healthy individuals. We observed that the cytokine inflammatory profiles of MDMi in response to drugs clustered separately between cohorts, with the 3D model showing a more defined separation between healthy and patient donors than 2D. By ranking donor and cytokine responses to drugs, we identified that drug efficacy was limited in AD patients and involved cohort-specific responsive cytokines. Our findings suggest that MDMi models have the potential to predict disease progression, stratify responders and identify biomarkers for estimating the efficacy of microglia-targeted drugs. Together, our pipeline could serve as a valuable tool to enhance the clinical translational value of preclinical drug screens and ultimately improve drug outcomes for AD.

cell biology↗

bioRxiv2022

An Alzheimer's disease patient-derived olfactory cell model identifies gene expression changes associated with cognition

An early symptom of Alzheimers disease (AD) is an impaired sense of smell, for which the molecular basis remains elusive. Here, we generated human olfactory neurosphere-derived (ONS) cells from people with AD and mild cognitive impairment (MCI), and performed global RNA sequencing to determine gene expression changes. ONS cells expressed markers of neuroglial differentiation, providing a unique cellular model to explore early AD-associated disease pathways. Our transcriptomics data from ONS cells revealed differentially expressed genes (DEGs) associated with cognitive processes in AD cells compared to MCI, or matched healthy controls (HC). A-Kinase Anchoring Protein 6 (AKAP6) was the most significantly altered gene in AD compared to both MCI and HC, and has been linked to cognitive function. The greatest change in gene expression of all DEGs occurred between AD and MCI. Gene pathway analysis revealed defects in multiple cellular processes with aging, intellectual deficiency and alternative splicing being the most significantly dysregulated in AD ONS cells. Our results demonstrate that ONS cells can provide a cellular model for AD that recapitulates disease-associated differences. We have revealed potential novel genes, including AKAP6 that may have a role in AD, particularly MCI to AD transition, and should be further examined.

neuroscience↗

bioRxiv2022

Microglial ferroptotic stress causes non-cell autonomous neuronal death

BackgroundFerroptosis is a form of regulated cell death characterised by lipid peroxidation as the terminal endpoint and a requirement for iron. Although it protects against cancer and infection, ferroptosis is also implicated in causing neuronal death in degenerative diseases of the central nervous system (CNS). The precise role for ferroptosis in causing neuronal death is yet to be fully resolved. MethodsTo elucidate the role of ferroptosis in neuronal death we utilised co-culture and conditioned medium transfer experiments involving microglia, astrocytes and neurones. We ratified clinical significance of our cell culture findings via assessment of human CNS tissue from cases of the fatal, paralysing neurodegenerative condition of amyotrophic lateral sclerosis (ALS). Finally, we utilised the SOD1G37R mouse model of ALS and a novel CNS-permeant ferroptosis inhibitor to verify pharmacological significance in vivo. ResultsWe found that sublethal ferroptotic stress selectively affecting microglia triggers an inflammatory cascade that results in non-cell autonomous neuronal death. Central to this cascade is the conversion of astrocytes to a neurotoxic state. We show that spinal cord tissue from cases of ALS exhibits a signature of ferroptosis that encompasses atomic, molecular and biochemical features. Moreover, a molecular correlation between ferroptosis and neurotoxic astrocytes evident in ALS-affected spinal cord is recapitulated in the SOD1G37R mouse model where treatment with the novel, CNS-permeant ferroptosis inhibitor, CuII(atsm), ameliorated these markers and was neuroprotective. ConclusionsBy showing that microglia responding to sublethal ferroptotic stress culminates in non-cell autonomous neuronal death, our results implicate microglial ferroptotic stress as a rectifiable cause of neuronal death in neurodegenerative disease. As ferroptosis is currently primarily regarded as an intrinsic cell death phenomenon, these results introduce an entirely new pathophysiological role for ferroptosis in disease.

neuroscience↗

bioRxiv2022

A sporadic Alzheimer's blood-brain barrier model for developing ultrasound-mediated delivery of Aducanumab and anti-Tau antibodies.

RationaleThe blood-brain barrier (BBB) is a major impediment to therapeutic intracranial drug delivery for the treatment of neurodegenerative diseases, including Alzheimers disease (AD). Focused ultrasound applied together with microbubbles (FUS+MB) is a novel technique to transiently open the BBB and increase drug delivery. Evidence suggests that FUS+MB is safe, however the effects of FUS+MB on human BBB cells, especially in the context of AD, remain sparsely investigated. MethodsHere we generated BBB cells (induced brain endothelial cells (iBECs) and astrocytes (iAstrocytes)) from apolipoprotein E gene allele E4 (APOE4, high AD risk) and allele E3 (APOE3, lower AD risk) carrying patient-derived induced pluripotent stem cells (iPSCs). We then developed a human sporadic AD BBB cell platform to investigate the effects of FUS+MB on BBB cells and screen for the delivery of two potentially therapeutic AD antibodies. ResultsWe utilized this robust and reproducible human BBB model to demonstrate increased delivery of therapeutic AD antibodies across the BBB following FUS+MB treatment, including an analogue of Aducanumab (AduhelmTM; anti-amyloid-{beta}) and a novel anti-Tau antibody RNF5. Our results also demonstrate the safety of FUS+MB indicated by minimal changes in the cell transcriptome as well as little or no changes in cell viability and inflammatory responses within the first 24 h post FUS+MB. Finally, we report a more physiologically relevant hydrogel-based 2.5D BBB model as a key development for FUS+MB-mediated drug delivery screening, with potentially higher translational utility. ConclusionOur results demonstrate an important translatable patient BBB cell model for identifying FUS+MB-deliverable drugs and screening for cell- and patient-specific effects of FUS+MB, accelerating the use of FUS+MB as a therapeutic modality in AD. One Sentence SummaryFocused ultrasound increases the in vitro delivery of therapeutic antibodies Aducanumab and anti-Tau in a sporadic Alzheimers disease patient-derived blood-brain barrier cell model.

neuroscience↗

bioRxiv2021

Alzheimer's disease alters astrocytic functions related to neuronal support andtranscellular internalization of mitochondria

Under physiological conditions in vivo astrocytes internalize and degrade neuronal mitochondria in a process called transmitophagy. Mitophagy is widely reported to be impaired in neurodegeneration but it is unknown whether and how transmitophagy is altered in Alzheimers disease (AD). Here we report that the internalization and degradation of neuronal mitochondria are significantly increased in astrocytes isolated from aged AD mouse brains. We also demonstrate for the first time a similar phenomenon between human neurons and AD astrocytes, and in murine hippocampi in vivo. The results suggest the involvement of S100a4 in impaired mitochondrial transfer between neurons and aged AD astrocytes. Significant increases in the mitophagy regulator Ambra1 were observed in the aged AD astrocytes. These findings demonstrate altered neuron-supporting functions of aged AD astrocytes and provide a starting point for studying the molecular mechanisms of transmitophagy in AD.

neuroscience↗

bioRxiv2021

Rapid analysis of strigolactone receptor activity in a Nicotiana benthamiana dwarf14 mutant

DWARF14 (D14) is an [a]/{beta}-hydrolase and receptor for the plant hormone strigolactone (SL) in angiosperms. Upon SL perception, D14 works with MORE AXILLARY GROWTH2 (MAX2) to trigger polyubiquitination and degradation of DWARF53(D53)-type proteins in the SUPPRESSOR OF MAX2 1-LIKE (SMXL) family. We used CRISPR-Cas9 to generate knockout alleles of the two homoeologous D14 genes in the Nicotiana benthamiana genome. The Nbd14a,b double mutant had several phenotypes that are consistent with the loss of SL perception in other plants, including increased axillary bud outgrowth, reduced height, shortened petioles, and smaller leaves. A ratiometric fluorescent reporter system was used to monitor degradation of SMXL7 from Arabidopsis thaliana (AtSMXL7) after transient expression in N. benthamiana and treatment with the strigolactone analog GR24. AtSMXL7 was degraded after treatment with GR245DS, which has the stereochemical configuration of SLs, as well as its enantiomer GR24ent-5DS . In Nbd14a,b leaves, AtSMXL7 abundance was unaffected by GR24. Transient coexpression of AtD14 with the AtSMXL7 reporter in Nbd14a,b restored the degradation response to GR24, but required an active catalytic triad. With this platform, we evaluated the ability of several AtD14 mutants that had not been characterized in plants to target AtSMXL7 for degradation.

plant biology↗

bioRxiv2021

3D models of Alzheimer's disease patient microglia recapitulate disease phenotype and show differential drug responses compared to 2D

Alzheimers disease (AD) is an incurable neurodegenerative disorder with a rapidly increasing prevalence worldwide. Current approaches targeting hallmark pathological features of AD have had no consistent clinical benefit. Neuroinflammation is a major contributor to neurodegeneration and hence, microglia, the brains resident immune cells, are an attractive target for potentially more effective therapeutic strategies. However, there is no current in vitro model system that faithfully recapitulates patient-specific microglial characteristics. To address this shortcoming, we developed novel 3D models of monocyte-derived microglia-like cells (MDMi) from AD patients. MDMi in 3D exhibited mature microglial features, including a highly branched morphology and enhanced bonafide microglial marker expression compared to 2D. Moreover, AD MDMi in 3D co-cultures with neuro-glial cells showed altered cell-to-cell interactions, growth factor and cytokine secretion profiles and responses to amyloid-{beta}. Drug screening assays in 3D AD MDMi revealed different cytokine responses compared to 2D. Our study demonstrates disease- and drug-specific responses in 3D MDMi models that are not apparent in 2D and presents a new 3D platform for more effective and personalised drug testing.

neuroscience↗

bioRxiv2020

Disease specific alterations in the olfactory mucosa of patients with Alzheimer's disease

Olfactory dysfunction manifests early in several neurodegenerative disorders. Olfaction is orchestrated by olfactory mucosal cells located in the upper nasal cavity. However, it is unclear how this tissue reflects key neurodegenerative features in Alzheimers disease. Here we report that Alzheimers disease olfactory mucosal cells obtained from live individuals secrete toxic amyloid-beta. We detail cell-type-specific gene expression patterns, unveiling 147 differentially expressed disease-associated genes compared to the cognitively healthy controls, and 5 distinct populations in globose basal cell -, myofibroblast-, and fibroblast/ stromal - like cells in vitro. Overall, coordinated alteration of RNA and protein metabolism, inflammatory processes and signal transduction were observed in multiple cell populations, suggesting a key role in pathophysiology. Our results demonstrate the potential of olfactory cell cultures in modelling Alzheimers disease advocate their use for diagnostic purposes. Moreover, for the first time we provide single cell data on olfactory mucosa in Alzheimers disease for investigating molecular and cellular mechanisms associated with the disease.

neuroscience↗

bioRxiv2020

ALS monocyte-derived microglia reveal cytoplasmic TDP-43 accumulation, DNA damage, and cell-specific impairment of phagocytosis associated with disease progression.

AimsAmyotrophic lateral sclerosis (ALS) is a multifactorial neurodegenerative disease characterised by the loss of upper and lower motor neurons. Neuroinflammation mediated by microglial activation is evident in post-mortem brain tissues, and in brain imaging of patients with ALS. However, the exact role of microglia in ALS remains to be elucidated partly due to the lack of an accurate microglial model system that is able to recapitulate the clinical pathology of ALS. Moreover, direct sampling of microglia from patients with ALS is not feasible, further limiting the study of microglial function in ALS. To address this shortcoming, we describe an approach that generates monocyte-derived microglia (MDMi) that are capable of expressing molecular markers, and functional characteristics similar to resident human brain microglia. Importantly, MDMi can be routinely and reproducibly generated from ALS patient blood, and reveal patient heterogeneity associated with age, sex and disease subgroup. MethodsMDMi were successfully established from all 30 ALS patients, including 15 patients with slow disease progression, 6 with intermediate progression, and 9 with rapid progression, together with 20 non-affected heathy controls (HC). ResultsOur ALS MDMi model recapitulated canonical pathological features of ALS including non-phosphorylated and phosphorylated-TDP-43-positive pathological inclusions. We further observed significantly impaired phagocytosis, altered cytokine expression and microglial morphology, as well as elevated DNA damage in ALS compared to HC MDMi. Abnormal phagocytosis was observed in all ALS cases, and was correlated to the progression of disease. Moreover, in-depth analysis of individual microglia revealed cell-specific variation in phagocytic function that was significantly altered, and exacerbated in rapid disease progression. ConclusionsOur approach enabled us to generate ALS patient microglia from peripheral blood samples using a rapid, robust, cost-effective, and reproducible protocol. We have shown that ALS monocyte-derived microglia have significantly altered functional behaviour compared to age-matched HCs, with a major deficit in phagocytic activity. This is also the first demonstration of abnormal TDP-43 localisation in microglia grown from ALS patients. Overall, this approach is highly applicable to monitor disease progression and can be applied as a functional readout in clinical trials for anti-neuroinflammatory agents. Additionally, this model system can be used as a basis for personalised therapeutic treatment for ALS, as well as other neurodegenerative diseases.

neuroscience↗

bioRxiv2020

Disrupted copper availability in sporadic ALS: Implications for CuII(atsm) as a treatment option

ObjectiveThe copper compound CuII(atsm) is in phase 2/3 testing for treatment of the neurodegenerative disease amyotrophic lateral sclerosis (ALS). CuII(atsm) consistently and reproducibly ameliorates neurodegeneration in mutant SOD1 mouse models of ALS where its neuroprotective activity has been ascribed in part to improving availability of copper to essential cuproenzymes. However, SOD1 mutations cause only ~2% of ALS cases with most cases being of unknown aetiology. Therapeutic pertinence of CuII(atsm) to sporadic ALS is therefore unclear. MethodsWe assayed post-mortem spinal cord tissue from sporadic cases of ALS for the anatomical and biochemical distribution of copper, the expression of genes involved in copper handling, and the activities of cuproenzymes. ResultsThe natural distribution of copper is disrupted in sporadic ALS. The ALS-affected tissue has a molecular signature consistent with an unsatiated requirement for copper and cuproenzyme activity is affected. Copper levels are decreased in the ventral grey matter, the primary anatomical site of neuronal loss in ALS. InterpretationMice expressing mutant SOD1 recapitulate salient features of ALS. The unsatiated requirement for copper that is evident in these mice is a biochemical target for CuII(atsm). Evidences provided here for disrupted copper bioavailability in human cases of sporadic ALS indicate that a therapeutic mechanism for CuII(atsm) involving copper bioavailability is pertinent to sporadic cases of ALS, and not just those involving mutant SOD1.

neuroscience↗