Biology subjects

Mead, R. J.

Publications and source records attributed to Mead, R. J..

3 recordsLinked to original sources

bioRxiv2025

Comparison of AAV9-driven motor neuron transduction following different CNS-directed delivery methods in mice

AbstractO_ST_ABSBackgroundC_ST_ABSGene therapies are promising for diseases previously considered incurable. Adeno-associated virus serotype 9 (AAV9) demonstrates remarkable tropism for motor neurons (MNs) and represents an exciting candidate to target genetic causes of motor neuron diseases like amyotrophic lateral sclerosis (ALS). However, systemic delivery risks immunogenicity and off-target effects, therefore localised delivery to the CNS is advantageous. New methodWe assessed MN transduction in wild-type mice using AAV9-controlled, cytomegalovirus-promoter driven, enhanced GFP expression. Intra-cisterna magna (ICM) and intra-cerebroventricular (ICV) methods were compared. Four weeks post-delivery, GFP positivity in MN and astrocytes were quantified via immunohistochemical approaches and viral genome copy number determined by qPCR. ResultsAll delivery methods achieved high MN transduction in lumbar spinal cord (>68%). Unilateral ICV delivery provided the highest and most consistent levels (89 {+/-} 3%), and minimal peripheral viral copies. ICV delivery resulted in higher astrocytic transduction, most notably in the cortex. Brainstem MN transduction was high with all methods (>55%). We failed to find evidence of neuronal transduction in motor cortex. Viral genome copies trended higher in spinal cord and brainstem with ICV approaches, however further work is required to understand how bilateral delivery leads to such profound increases. Comparison to existing methodsWhilst several routes of administration into cerebrospinal fluid exist, direct comparisons for targeting MNs in vivo remain limited. ConclusionsOverall, consideration of gene therapy delivery methods is critical to ensure that the most appropriate administration route is chosen to reach MNs effectively, selectively, and at high levels to exact biological effects. HighlightsO_LICSF delivery of AAV9 targets >68% of lumbar spinal cord (SC) motor neurons C_LIO_LIUnilateral ICV yields high and consistent lumbar SC motor neuron transduction (>88%) C_LIO_LIUnilateral ICV results in the lowest number of peripheral viral copies C_LIO_LIICV targets significantly more astrocytes, particularly in cortex C_LIO_LIBilateral ICV leads to significantly higher viral copies in the liver C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC="FIGDIR/small/662642v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@bd83a5org.highwire.dtl.DTLVardef@df63aorg.highwire.dtl.DTLVardef@a09142org.highwire.dtl.DTLVardef@1a0887a_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

M102, a combined NRF2 and HSF-1 activator for neuroprotection in amyotrophic lateral sclerosis.

M102 is a central nervous system (CNS) penetrant small molecule electrophile which activates in vivo the NFE2-related factor 2 antioxidant response element (NRF2-ARE) pathway, as well as transcription of heat-shock element (HSE) associated genes. In the TDP-43Q331K transgenic mouse model of ALS dosed subcutaneously at 5mg/kg OD or 2.5mg/kg BD with M102, significant improvements in compound muscle action potential (CMAP) amplitude of hind limb muscles and gait parameters were observed at 6 months of age, with associated target engagement. An oral dose response study of M102 in SOD1G93A transgenic mice showed a dose-dependent improvement in the CMAP of hindlimb muscles which correlated with preservation of lumbar spinal motor neurons at the same time point. These data enabled prediction of human efficacious exposures and doses, which were well within the safety margin predicted from Good Laboratory Practice (GLP) toxicology studies. A parallel program of work in vitro showed that M102 rescued motor neuron survival in co-culture with patient-derived astrocytes from sporadic, C9orf72 and SOD1 cases. Markers of oxidative stress, as well as indices of TDP-43 proteinopathy were also reduced by exposure to M102 in these in vitro models. This comprehensive package of preclinical efficacy data across two mouse models as well as patient-derived astrocyte toxicity assays, provides a strong rationale for clinical evaluation of M102 in ALS patients. Combined with the development of target engagement biomarkers and the completed preclinical toxicology package, a clear translational pathway to testing in ALS patients has been developed. One Sentence SummaryM102, a dual NRF2/HSF1 activator, slows disease progression in 2 mouse models and exerts neuroprotection in human cellular models of ALS.

neuroscience↗

bioRxiv2024

Glutathione Oxidation in Cerebrospinal Fluid as a Biomarker of Oxidative Stress in Amyotrophic Lateral Sclerosis

BackgroundOxidative stress is a key feature of several neurodegenerative diseases, including Amyotrophic Lateral Sclerosis (ALS). Identification of reliable biomarkers of oxidative stress would be beneficial for drug-target engagement studies. MethodsWe performed unbiased quantitative mass spectrometry (MS)-based analysis to measure changes in protein abundance and oxidation in cerebrospinal fluid (CSF) from a cohort of ALS patients and healthy controls at two time points (approximately four months apart) to capture disease progression. In addition, we developed a sensitive and targeted quantitative MS method to measure glutathione oxidation state in the same sets of CSF samples. ResultsProteomic analysis of CSF revealed statistically significant changes in the abundance of several proteins, including CHIT1, CHI3L1, CHI3L2 and COL18A1 in ALS patients compared to healthy controls at both time points. Several sites of protein oxidation were significantly altered in ALS compared to healthy controls, and total levels of reversible protein oxidation were elevated in ALS patients. Given that glutathione oxidation could be a useful biomarker of oxidative stress, we also measured glutathione and its oxidation state in CSF in the same cohorts of samples. Total GSH (tGSH), GSSG levels and the GSSG/GSH ratio were significantly higher in the ALS than in the healthy control group for both time points. For the first visit, fold changes of tGSH, GSSG, and GSSG/GSH ratio in ALS compared to HC were 1.33 (p = 0.0215), 1.54 (p = 0.0041) and 1.80 (p = 0.0454), respectively. For the second visit, these values were 1.50 (p = 0.0143), 2.00 (p = 0.0018) and 2.14 (p = 0.0120), respectively. Furthermore, we found positive correlations between disease duration until the first visit and total glutathione (tGSH), GSSG and GSSG/GSH ratio. Finally, there was a strong positive correlation between the total intensity of reversibly oxidised proteins and the ratio of GSSG/GSH in ALS patients at both visits. ConclusionWe propose that measuring levels of glutathione oxidation in CSF could act as a stratification biomarker to select ALS patients for antioxidant therapy and an approach to monitor the treatment response to therapeutic agents targeting oxidative stress.

neuroscience↗