Biology subjects

Gregory, J. M.

Publications and source records attributed to Gregory, J. M..

9 recordsLinked to original sources

bioRxiv2025

Brain Iron as a Surrogate Biomarker of Pathological TDP-43 Identifies Brain Region-Specific Signatures in Ageing, Alzheimer's Disease and Amyotrophic Lateral Sclerosis

BackgroundTDP-43 pathology is a defining feature of several neurodegenerative diseases, but its prevalence and regional distribution in ageing and disease are not well characterised. We investigated the burden of brain TDP-43 pathology across ageing, Alzheimers disease (AD), and amyotrophic lateral sclerosis (ALS), and examined ferritin as a region-specific correlate of TDP-43 pathology. MethodsPathological TDP-43 was detected using an HDGFL2 cryptic exon in situ hybridisation probe and a TDP-43 RNA aptamer, providing greater sensitivity and specificity than antibody-based approaches. Amygdala, hippocampus, and frontal cortex tissue was analysed from non-neurological controls (ages 40-80), AD cases, and ALS cases. Ferritin (as a proxy for iron accumulation) was quantified in parallel to assess its association with TDP-43 pathology. FindingsTDP-43 pathology was detectable from the fourth decade of life, with a 4.5-fold increase in hippocampal involvement after age 60 years. In AD, pathology was present in 90% of cases and distinguished from ageing by selective amygdala involvement. In ALS, TDP-43 pathology was nearly ubiquitous across all regions studied. Regional ferritin strongly predicted TDP-43 burden: amygdala ferritin explained 87% of TDP-43 variance in ALS and 66% in AD, while hippocampal ferritin differentiated AD from controls. Across AD, ferritin explained between 43-81% of regional TDP-43 variance. InterpretationTDP-43 brain pathology emerges in midlife with increased involvement after age 60 years, exhibits disease-specific regional signatures in AD and ALS, and is closely linked to ferritin accumulation. As TDP-43 confers a worse prognosis in AD, the capacity of ferritin, detectable with iron-sensitive MRI, to serve as a proxy for regional TDP-43 burden highlights its promise as a biomarker for disease stratification and prognosis. Short AbstractHere we show that pathological TDP-43 emerges during normal ageing from the fourth decade of life, with a 4.5-fold increase in hippocampal involvement after 60 years. In Alzheimers disease (AD), TDP-43 pathology was present in 90% of cases and distinguished from ageing by disproportionate amygdala involvement, while in amyotrophic lateral sclerosis (ALS) it was nearly ubiquitous across hippocampus, amygdala, and frontal cortex. Using sensitive detection tools, we demonstrate that region-specific ferritin strongly predicts TDP-43 burden: amygdala ferritin explained 87% of variance in ALS and 66% in AD, while hippocampal ferritin differentiated AD from controls. Across AD, ferritin levels in all three regions explained 43-81% of TDP-43 variance. As TDP-43 pathology confers a worse prognosis in AD, the ability of ferritin, quantifiable with iron-sensitive MRI, to serve as a proxy for regional TDP-43 burden highlights its potential as a biomarker for disease stratification and prognostic assessment. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC="FIGDIR/small/680028v1_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@9c54b3org.highwire.dtl.DTLVardef@17cb415org.highwire.dtl.DTLVardef@12dabeorg.highwire.dtl.DTLVardef@1d72f95_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LITDP-43 brain pathology occurs in normal ageing from early in the fourth decade, characterised by a 4.5-fold increase in hippocampus pathology from the sixth decade. C_LIO_LITDP-43 brain pathology is detectable in 90% of AD cases, with a disease-signature of increased amygdala pathology relative to age-matched controls. C_LIO_LIIn ALS, TDP-43 is nearly ubiquitous in amygdala, hippocampus and frontal cortex. C_LIO_LIHippocampus high brain ferritin distinguishes AD from and age-matched controls C_LIO_LIBrain ferritin is a brain region-specific marker of TDP-43 pathology in ageing and disease, with amygdala ferritin explaining 87% of the variance in amygdala TDP-43 pathology in ALS, and 66% of amygdala TDP-43 pathology in AD C_LIO_LIIn AD, ferritin levels for all three brain regions explain between 43-81% of variance in their TDP-43 pathology levels C_LI

neuroscience↗

bioRxiv2025

Improved detection of pre-symptomatic, non-central nervous system TDP-43 pathology in amyotrophic lateral sclerosis using RNA aptamer

The recognition that disease-associated proteinopathies can manifest in peripheral organs outside the central nervous system preceding the onset of neurological symptoms, has transformed our understanding of Parkinsons disease, in wide terms of pathogenesis, detection and diagnosis. For amyotrophic lateral sclerosis, non-motor symptoms, and non-central nervous system pathologies are gaining increased recognition but remain incompletely understood. Here, using a TDP-43 RNA aptamer and a Stathmin-2 cryptic exon transcript BaseScopeTM ISH probe, we identify widespread peripheral organ TDP-43 pathology prior to motor symptom onset in a discovery cohort of ante-mortem tissues from people who went on to develop ALS. Peripheral organs exhibiting both TDP-43 toxic gain- and loss-of function include muscle, lymph node, gallbladder, colon and with notably high incidence, skin. Given the accessibility of skin as a readily biopsiable tissue, representing a promising substrate for the detection of disease-associated proteinopathies and the development of minimally invasive biomarkers, we established an extended cohort of ante-mortem skin samples for TDP-43 pathology validation and further investigation. In skin biopsies taken during life from 17 individuals who went on to develop ALS we identify TDP-43 pathology from all 17 individuals in a wide distribution of anatomical sites, up to 26.5 years before ALS diagnosis - a presymptomatic period comparable to that observed for skin -synucleinopathy in Parkinsons disease. TDP-43 pathology was most abundant in skin biopsies from the back and shoulder, with sweat and sebaceous glands showing the highest involvement. TDP-43 pathology was also associated with structural changes. As skin -synucleinopathy has been established as a biomarker for both the detection of Parkinsons disease and the differentiation of Parkinsons disease from multiple system atrophy, we propose that skin TDP-43 likewise holds diagnostic and discrimination potential for diseases characterised by TDP-43 proteinopathy. Short AbstractPeripheral manifestations of neurodegenerative disease can precede neurological symptoms and serve as biomarkers, as shown by -synuclein in the skin of individuals who later develop Parkinsons disease. In amyotrophic lateral sclerosis (ALS), however, the distribution and diagnostic potential of peripheral TDP-43 pathology remain unclear. Using a TDP-43 RNA aptamer and a cryptic STMN2 BaseScope probe, we examined ante-mortem tissues from individuals who later developed ALS. In a discovery cohort, we detected widespread pre-symptomatic TDP-43 pathology across multiple organs, with skin emerging as the most consistent site. We then validated these findings in a validation cohort comprising 17 individuals, all of whom exhibited TDP-43 pathology enriched in sweat glands and structural changes detectable up to 26.5 years before ALS diagnosis. These findings establish skin as a robust and accessible site of pre-symptomatic TDP-43 pathology, supporting its potential as a minimally invasive biomarker for early diagnosis and disease stratification in ALS. SummaryMuch like skin -synucleinopathy has transformed biomarker development in Parkinsons disease, this study identifies skin TDP-43 pathology as a promising early marker of ALS. The results open avenues for earlier diagnosis and stratification in a disease where intervention is most needed before symptoms appear. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=143 SRC="FIGDIR/small/648122v2_ufig1.gif" ALT="Figure 1"> View larger version (59K): org.highwire.dtl.DTLVardef@14cc6c0org.highwire.dtl.DTLVardef@18c69f7org.highwire.dtl.DTLVardef@1811265org.highwire.dtl.DTLVardef@dea8bc_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIPresymptomatic TDP-43 pathology occurs across a range on non-CNS peripheral organ systems including skin, gastrointestinal tract and lymph nodes prior to motor symptom onset in people who went on to develop ALS. C_LIO_LIIn skin, presymptomatic TDP-43 pathology is associated with structural changes and can be detected up to 26.5 years prior to motor symptoms in ALS. C_LIO_LIAs for Parkinsons disease, shoulder and back represents optimal skin sampling sites for pre-symptomatic pathology in ALS. C_LIO_LISweat and sebaceous glands present with high levels of TDP-43 pathology, offering a promising biomarker target for early pathology detection. C_LI One Sentence SummaryUsing distinct biomarker discovery and validation ante-mortem tissue cohorts, we provide evidence of pre-symptomatic TDP-43 pathology across diverse non-CNS peripheral tissues, including skin decades before ALS symptom onset, highlighting skin TDP-43 pathology as a potential early biomarker for ALS and related TDP-43 proteinopathies

pathology↗

bioRxiv2025

Fingerprinting disease-derived protein aggregates reveals unique signature of Motor Neuron Disease

Inappropriate aggregation of TAR DNA-binding protein 43 (TDP-43) is a hallmark of motor neuron disease (MND). Current methods for quantifying heterogeneous aggregate populations in biofluids are limited, precluding their routine use in diagnosis and disease monitoring. Single molecule microscopy methods overcome these limitations to deliver quantitative morphological and compositional fingerprinting of molecular assemblies containing TDP-43. Here, we demonstrate the application of such methods to extracts from donor brain tissues. We show the number and morphology of aggregates derived from frontal cortex and cerebellar samples is sufficient to distinguish MND donors from neurologically normal controls, as well as between different MND cohorts. In addition, we compare proteomic and microscopic compositional profiles, demonstrating how complementary insights delivered by each technique can enhance our understanding of disease mechanisms. These single molecule assays will inform future diagnostic and stratification technologies, improving our ability to deliver patient care in a timely and targeted manner.

molecular biology↗

bioRxiv2025

Differential Cellular Mechanisms Underlie Language and Executive Decline in Amyotrophic Lateral Sclerosis

Cognitive manifestations, including impairment in language and executive functions, are seen in amyotrophic lateral sclerosis (ALS), but the mechanisms that underlie these deficits remain unclear. To address this, we mapped prefrontal cortex regions from ALS patients by integrating spatial and single-nucleus transcriptomics in a cognitively stratified patient cohort. We uncover that cognitive impairment in ALS is associated with distinct patterns of neuronal dysfunction and glial-vascular dysregulation that vary by region and cognitive subtype. Executive dysfunction is linked to reduced mitochondrial and synaptic activity in neurons localized to the deeper layers of the dorsolateral prefrontal cortex, whereas language-related deficits track with a more diffuse, pan-regional response involving both glial and vascular abnormalities. Our analyses also identify signatures in the prefrontal cortex that span both motor and cognitive phenotypes, including a multicellular gliosis response. The findings reveal that the clinical heterogeneity of ALS is driven by phenotype-specific molecular and cellular interactions in motor and non-motor regions of the brain.

genomics↗

bioRxiv2025

Machine learning identifies routine blood tests as accurate predictive measures of pollution-dependent poor cognitive function

BackgroundSeveral modifiable risk factors for dementia and related neurodegenerative diseases have been identified including education level, socio-economic status, and environmental exposures - however, how these population-level risks relate to individual risk remains elusive. To address this, we assess over 450 potential risk factors in one deeply clinically and demographically phenotyped cohort using random forest classifiers to determine predictive markers of poor cognitive function. This study aims to understand early risk factors for dementia by identifying predictors of poor cognitive performance amongst a comprehensive battery of imaging, blood, atmospheric pollutant and socio-economic measures. MethodsRandom forest modelling was used to determine significant predictors of poor cognitive performance in a cohort of 324 individuals (age 61.6 {+/-} 4.8 years; 150 males, 174 females) without extant neurological disease. 457 features were assessed including brain imaging measures of volume and iron deposition, blood measures of anaemia, inflammation, and heavy metal levels, social deprivation indicators and atmospheric pollution exposure. ResultsRoutinely assessed markers of anaemia including mean corpuscular haemoglobin concentration were identified as robust predictors of poor general cognition, where both extremes (low and high) were associated with poor cognitive performance. The strongest, most consistent predictors of poor cognitive performance were environmental measures of atmospheric pollution, in particular, lead, carbon monoxide, and particulate matter. Feature analysis demonstrated a significant negative relationship between low mean corpuscular haemoglobin concentration and high levels of atmospheric pollutants highlighting the potential of routinely assessed blood tests as a predictive measure of pollution-dependent cognitive functioning, at an individual level. ConclusionsTaken together, these data demonstrate how routine, inexpensive medical testing and local authority initiatives could help to identify and protect at-risk individuals. These findings highlight the potential to identify individuals for targeted, cost effective medical and social interventions to improve population cognitive health. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=66 SRC="FIGDIR/small/632396v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@1cda09org.highwire.dtl.DTLVardef@2e9243org.highwire.dtl.DTLVardef@1849bfcorg.highwire.dtl.DTLVardef@11cf9aa_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2023

A High-Fat and Fructose Diet in Dogs Mirrors Insulin Resistance and β-cell Dysfunction Characteristic of Impaired Glucose Tolerance in Humans

This study examined the impact of a hypercaloric high-fat high-fructose diet (HFFD) in dogs as a potential model for human impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM). The HFFD not only led to weight gain but also triggered metabolic alterations akin to the precursors of human T2DM, notably insulin resistance and {beta}-cell dysfunction. Following the HFFD intervention, the dogs exhibited a 50% decrease in insulin sensitivity within the first four weeks, paralleling observations in the progression from normal to IGT in humans. Calculations of the insulinogenic index using both insulin and C-peptide revealed a significant and sustained decrease in early-phase insulin release, with partial compensation in the later phase, predominantly stemming from reduced hepatic insulin clearance. In addition, the Disposition Index, representing the {beta}-cells capacity to compensate for diminished insulin sensitivity, fell dramatically. These results confirm that a HFFD can instigate metabolic changes in dogs akin to the early stages of progression to T2DM in humans. The study underscores the potential of using dogs subjected to a HFFD as a model organism for studying human IGT and T2DM.

physiology↗

bioRxiv2023

Distinct neuroinflammatory signatures exist across genetic and sporadic ALS cohorts

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by progressive loss of upper and lower motor neurons. ALS is on a pathogenetic disease spectrum with frontotemporal dementia (FTD), with patients sometimes experiencing elements of both conditions (ALS-FTSD). For mutations associated with ALS-FTSD, such as the C9orf72 hexanucleotide repeat expansion (HRE), the factors influencing where an individual may lie on this spectrum require further characterisation. Here, using NanoString molecular barcoding with a panel of 770 neuroinflammatory genes, we interrogate inflammatory dysregulation at the level of gene expression. We identified 20 dysregulated neuroinflammatory genes in the motor cortex of deeply clinically phenotyped C9-ALS post-mortem cases, with enrichment of microglial and inflammatory response gene sets. Our analyses also revealed two distinct ALS-related neuroinflammatory panel signatures (NPS), NPS1 and NPS2, delineated by the direction of expression of proinflammatory, axonal transport and synaptic signalling pathways. Two genes with significant correlations to available clinical metrics were selected for validation: FKBP5 and BDNF. FKBP5 and its signalling partner, NF-{kappa}B, appeared to have a cell-type-specific staining distribution, with activated (i.e., nuclear) NF-{kappa}B immunoreactivity in C9-ALS. Expression of BDNF, a correlate of disease duration, was confirmed to be higher in individuals with long compared to short disease duration using BaseScope in situ hybridisation. Finally, we compared NPS between C9-ALS cases and those from deeply clinically phenotyped sporadic ALS (sALS) and SOD1-ALS cohorts, with NPS1 and NPS2 appearing across all cohorts. A subset of these signatures was also detected in publicly available RNA-sequencing data from independent C9-ALS and sALS cohorts, underscoring the relevance of these pathways across cohorts. Our findings highlight the importance of tailoring therapeutic approaches based on distinct molecular signatures that exist between and within genetic and sporadic cohorts.

neuroscience↗

bioRxiv2022

pTDP-43 aggregates accumulate in the gut and other non-central nervous system tissues prior to symptom onset in amyotrophic lateral sclerosis

ObjectiveNeurodegenerative diseases such as Parkinsons disease (PD), Alzheimers disease (AD) and amyotrophic lateral sclerosis (ALS) are traditionally considered strictly neurological disorders. However, clinical presentation is not restricted to neurological systems, and non-central nervous system (CNS) manifestations, particularly gastrointestinal (GI) symptoms, are common. Our objective was to understand the systemic distribution of pathology in archived non-CNS tissues, taken as part of routine clinical practice during life from people with ALS. DesignWe requested all surgical specimens of non-CNS tissue taken during life from 48 people with ALS, for whom evidence of the characteristic proteinopathy associated with ALS had been identified in the CNS after death (i.e., the pathological cytoplasmic accumulation of phosphorylated TDP-43 (pTDP-43) aggregates). Of the 48 patients, 13 had sufficient tissue for evaluation: 12 patients with sporadic ALS and 1 patient with a C9orf72 hexanucleotide repeat expansion. The final cohort consisted of 68 formalin-fixed paraffin embedded tissue samples from 22 surgical cases (some patients having more than one case over their lifetimes), representing 8 organ systems, which we examined for evidence of pTDP-43 pathology. The median age of tissue removal was 62.4 years old and median tissue removal to death was 6.3 years. ResultsWe identified pTDP-43 aggregates in multiple cell types of the GI tract (i.e., colon and gallbladder), including macrophages and dendritic cells within the lamina propria, as well as neuronal and glial cells of the myenteric plexus. Aggregates were also noted within lymph node parenchyma, blood vessel endothelial cells, and chondrocytes. We note that in all cases with non-CNS pTDP-43 pathology, aggregates were present prior to ALS diagnosis (median=3years) and, in some instances, preceded neurological symptom onset by more than 10 years. ConclusionThese data imply that patients with non-CNS symptoms may have occult protein aggregation that could be detected many years prior to neurological involvement. SummaryNeurodegenerative diseases such as Parkinsons disease (PD), Alzheimers disease (AD) and amyotrophic lateral sclerosis (ALS) are traditionally considered strictly neurological disorders. However, clinical presentation is not restricted to neurological systems, and non-central nervous system (CNS) manifestations, particularly gastrointestinal (GI) symptoms, are common. Our objective was to understand the systemic distribution of TDP-43 pathology in archived non-CNS tissues, taken as part of routine clinical practice during life from people with ALS. We identified pTDP-43 aggregates in multiple cell types of the GI tract (i.e., colon and gallbladder), and within lymph node parenchyma, blood vessel endothelial cells, and chondrocytes. We note that in all cases with non-CNS pTDP-43 pathology, aggregates were present prior to ALS diagnosis (median=24months) and, in some instances, preceded neurological symptom onset by more than 10years. These data imply that patients with non-CNS symptoms may have occult protein aggregation tha could be detected many years prior to neurological involvement. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=159 SRC="FIGDIR/small/484805v1_ufig1.gif" ALT="Figure 1"> View larger version (67K): org.highwire.dtl.DTLVardef@1f568c6org.highwire.dtl.DTLVardef@b1d99dorg.highwire.dtl.DTLVardef@45e643org.highwire.dtl.DTLVardef@1106d29_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical Abstract.C_FLOATNO Ante-mortem tissue cohort comprised of tissue taken from people with ALS demonstrates non-CNS accumulation of pTDP-43 aggregates prior to symptom onset. Schematic of workflow to identify pTDP-43 aggregates indicative of non-central nervous system (CNS) manifestations of ALS. Lower panel left: cartoon depicting organs and cell types that had evidence of pTDP-43 aggregation in ALS patient non-CNS ante-mortem tissue. Lower panel right: cartoon depicting organs with no evidence of pTDP-43 aggregation in ALS patient non-CNS ante-mortem tissue. C_FIG

neuroscience↗

bioRxiv2021

Random forest modelling of neuropathological features identifies microglial activation as an accurate pathological classifier of C9orf72-related amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are regarded as two ends of a pathogenetic spectrum, termed ALS-frontotemporal spectrum disorder (ALS-FTSD). However, it is currently difficult to predict where on the spectrum an individual will lie, especially for patients with C9orf72 hexanucleotide repeat expansions (HRE), a mutation associated with both ALS and FTD. It has been shown that both inflammation and protein misfolding influence aspects of ALS and ALS-FTSD disease pathogenesis, such as the manifestation or severity of motor or cognitive symptoms. Previous studies have highlighted markers which may influence C9orf72-associated disease presentation in a targeted fashion, though there has yet to be a systematic and quantitative assessment of common immunohistochemical markers to investigate the significance of these pathways in an unbiased manner. Here we report the first extensive digital pathological assessment with random forest modelling of pathological markers often used in neuropathology practice. This study profiles glial activation and protein misfolding in a cohort of deeply clinically profiled post-mortem tissue from patients with a C9orf72 HRE, who either met the criteria for a diagnosis of ALS or ALS-FTSD. We show that microglial immunohistochemical staining features, both morphological and spatial, are the best independent classifiers of disease status and that clinicopathological associations exist between microglial activation status and cognitive dysfunction in ALS-FTSD patients with C9orf72 HRE. Furthermore, we show that spatially resolved changes in FUS staining are also an accurate predictor of disease status, implying that liquid-liquid phase shift of this aggregation-prone RNA-binding protein may be important in ALS caused by a C9orf72 HRE. Our findings provide further support to the hypothesis of dysfunctional immune regulation and proteostasis in the pathogenesis of C9orf72 ALS and provide a framework for digital analysis of commonly used neuropathological stains as a tool to enrich our understanding of clinicopathological associations between cohorts.

neuroscience↗