Efficient induction of motor neuron disease in transgenic G93A SOD1 mice by prion-like seeding

Prion · 2026-02-17

Mutations in superoxide dismutase 1 (SOD1) cause paralysis in familial amyotrophic lateral sclerosis and promote its misfolding into neurotoxic aggregates. Previous studies have shown that mice expressing the ALS-causing G85R variant of SOD1 develop paralysis much faster after intraspinal injection of spinal homogenates from paralysed G85R SOD1 mice. These findings, and other studies in cell models, established the prionoid templating properties of misfolded mutant SOD1. Previously, however, we noted that the widely used Gur1-G93A SOD1 mice, which express at high levels and develop paralysis by 6 months of age, were resistant to seeding by homogenates from paralysed G93A mice. A line of G93A mice that expresses at very low levels (VLE-G93A) was responsive to seeding but at low efficiency. The poor susceptibility of G93A-SOD1 mice to seeding was not what we expected if prion-like propagation is essential to SOD1 ALS pathogenesis. In our prior studies, seeding homogenates from paralysed G93A-SOD1 mice were injected into the spine of newborn mice, leading us to question whether older G93A SOD1 mice might be more susceptible to seeding. Here, we establish that adult VLE G93A SOD1 mice (up to 12 months of age) injected intrathecally with seeding homogenates containing misfolded G93A or G85R SOD1 developed accelerated motor neuron disease efficiently. Thus, we demonstrate that both the route and age of inoculation can influence the efficiency of SOD1 seeding to induce motor neuron disease in VLE G93A-SOD1 mice. These data, together with our earlier reports, suggest that prion-like templating contributes to disease progression in SOD1-ALS.

Efficient induction of motor neuron disease in transgenic G93A SOD1 mice by prion-like seeding

Figshare · 2026-01-01

Mutations in superoxide dismutase 1 (SOD1) cause paralysis in familial amyotrophic lateral sclerosis and promote its misfolding into neurotoxic aggregates. Previous studies have shown that mice expressing the ALS-causing G85R variant of SOD1 develop paralysis much faster after intraspinal injection of spinal homogenates from paralysed G85R SOD1 mice. These findings, and other studies in cell models, established the prionoid templating properties of misfolded mutant SOD1. Previously, however, we noted that the widely used Gur1-G93A SOD1 mice, which express at high levels and develop paralysis by 6 months of age, were resistant to seeding by homogenates from paralysed G93A mice. A line of G93A mice that expresses at very low levels (VLE-G93A) was responsive to seeding but at low efficiency. The poor susceptibility of G93A-SOD1 mice to seeding was not what we expected if prion-like propagation is essential to SOD1 ALS pathogenesis. In our prior studies, seeding homogenates from paralysed G93A-SOD1 mice were injected into the spine of newborn mice, leading us to question whether older G93A SOD1 mice might be more susceptible to seeding. Here, we establish that adult VLE G93A SOD1 mice (up to 12 months of age) injected intrathecally with seeding homogenates containing misfolded G93A or G85R SOD1 developed accelerated motor neuron disease efficiently. Thus, we demonstrate that both the route and age of inoculation can influence the efficiency of SOD1 seeding to induce motor neuron disease in VLE G93A-SOD1 mice. These data, together with our earlier reports, suggest that prion-like templating contributes to disease progression in SOD1-ALS.

Fast and slow strains of misfolded mutant superoxide dismutase 1 in familial amyotrophic lateral sclerosis

Acta Neuropathologica Communications · 2026-02-25

Mutations in superoxide dismutase 1 (SOD1) account for ~ 10% of familial amyotrophic lateral sclerosis (fALS) cases. Most SOD1 ALS cases show a 2–5 year clinical course, but a subset of patients exhibit a slowly progressing illness lasting 10–20 years. Substantial evidence indicates that disease-causing mutations in SOD1 promote misfolding and aggregation. Spinal tissue homogenates from paralyzed transgenic mice containing misfolded mutant SOD1 accelerate paralysis when injected into the spine or sciatic nerve of young mutant SOD1 transgenic mice. Using this prion-like seeding model in G85R-SOD1:YFP transgenic mice to initiate the disease process, we show that human SOD1 variants associated with rapidly progressing ALS produce SOD1-ALS strains that cause paralysis earlier than mutations associated with slowly progressing disease. Our findings suggest that the heterogeneous clinical presentations of different SOD1 mutations in ALS could be linked to prion-like strain attributes that govern the templating and propagation kinetics of misfolded SOD1.

Progressive Supranuclear Palsy PERK Haplotype B Selectively Translates DLX1 Promoting Tau Toxicity

Journal of Neuroscience · 2026-02-18

The unfolded protein response (UPR) sensor PERK exists in haplotypes A and B. PERK-B confers increased risk for tauopathies like progressive supranuclear palsy (PSP), but the mechanisms distinguishing its function from PERK-A and contributing to its association with tauopathy remain unknown. Here, we developed a controlled cellular model for a pair-wise comparison of the two PERK haplotypes, finding their UPR functions nearly indistinguishable. Puromycin-based proteomics highlighted a subset of mRNA translation events that was permissible under the PERK-B-dependent, but not the PERK-A-dependent, UPR. One of the targets that escaped PERK-B suppression was the transcription factor DLX1, which is genetically linked to PSP risk. We found that DLX1 solubility shifted to a detergent-insoluble fraction in the human brain tissue from male and female PSP donors. Furthermore, silencing the fly homolog of DLX1 was sufficient to decrease tau-induced toxicity in vivo. Our results detail the haplotype-specific PERK-B/DLX-1 pathway as a novel driver of tau pathology in cells, flies, and likely the human brain, revealing new insights into PSP pathogenesis and potential therapeutic targets.

Optimization of Pre-Clinical Rodent Research Models of Human Shock: Part 2 Trauma, Burn, and the Gut Microbiome

Shock · 2026-05-07

Rodent models are critical tools in the study of trauma and burn injury, giving mechanistic insights into the unique pathophysiological response and the systemic complications that follow. These models allow researchers to control injury patterns, longitudinally assess immune and metabolic responses, and evaluate therapeutic strategies in ways that are not feasible in human subjects. In this second part of our review, we examine how experimental trauma and burn models have evolved to better replicate the clinical trajectory of critically ill patients, with emphasis on polytrauma, burn injury, and translational relevance. We also highlight the role of the gut microbiome in the pathogenesis of shock within sepsis, trauma and burn, and review how rodent models have been used to investigate dysbiosis and test microbiome-targeted interventions. Although interspecies differences pose translational challenges, ongoing refinements in model selection, injury models, microbiome characterization, and reverse-translational approaches continue to expand the utility of rodent models, allowing researchers to discover vital insights into the complex pathophysiology of these critically ill patients and potential therapeutic targets that guide further investigation.

Efficient induction of motor neuron disease in transgenic G93A SOD1 mice by prion-like seeding

Figshare · 2026-01-01

Mutations in superoxide dismutase 1 (SOD1) cause paralysis in familial amyotrophic lateral sclerosis and promote its misfolding into neurotoxic aggregates. Previous studies have shown that mice expressing the ALS-causing G85R variant of SOD1 develop paralysis much faster after intraspinal injection of spinal homogenates from paralysed G85R SOD1 mice. These findings, and other studies in cell models, established the prionoid templating properties of misfolded mutant SOD1. Previously, however, we noted that the widely used Gur1-G93A SOD1 mice, which express at high levels and develop paralysis by 6 months of age, were resistant to seeding by homogenates from paralysed G93A mice. A line of G93A mice that expresses at very low levels (VLE-G93A) was responsive to seeding but at low efficiency. The poor susceptibility of G93A-SOD1 mice to seeding was not what we expected if prion-like propagation is essential to SOD1 ALS pathogenesis. In our prior studies, seeding homogenates from paralysed G93A-SOD1 mice were injected into the spine of newborn mice, leading us to question whether older G93A SOD1 mice might be more susceptible to seeding. Here, we establish that adult VLE G93A SOD1 mice (up to 12 months of age) injected intrathecally with seeding homogenates containing misfolded G93A or G85R SOD1 developed accelerated motor neuron disease efficiently. Thus, we demonstrate that both the route and age of inoculation can influence the efficiency of SOD1 seeding to induce motor neuron disease in VLE G93A-SOD1 mice. These data, together with our earlier reports, suggest that prion-like templating contributes to disease progression in SOD1-ALS.

Age- and Sex- Driven Transcriptional and Metabolic Diversity in Myeloid-Derived Suppressor Cells After Mouse Sepsis

bioRxiv (Cold Spring Harbor Laboratory) · 2025-10-07

Sepsis induces profound immune dysregulation, often resulting in chronic critical illness characterized by persistent immunosuppression and poor outcomes. Myeloid-derived suppressor cells (MDSCs) are central mediators of this immunosuppressive phenotype, yet the influence of age and sex on their transcriptional and metabolic states remain poorly understood. Here, we employed single-cell RNA sequencing of splenic leukocytes from young (3-4 months) and older (18-24 months) adult male and female mice subjected to a clinically relevant murine sepsis model to define age- and sex-specific MDSC phenotypes. We identified significant differences regarding age and sex in MDSC expansion, transcriptome, canonical pathway activation, RNA velocity, mitochondrial metabolism, and predicted cell-cell communication after sepsis. Using drug2cell analysis of total leukocytes we also identified cohort-specific drug target profiles. These findings underscore the importance of age and sex in shaping sepsis-induced MDSC biology and suggest that personalized immunomodulatory strategies targeting MDSCs could improve sepsis outcomes.

Corrigendum to “Functional connectivity within sensorimotor cortical and striatal regions is regulated by sepsis in a sex-dependent manner” [NeuroImage 305 (2025) 120995]

NeuroImage · 2025-01-19

Sepsis Induces Age- and Sex-Specific Chromatin Remodeling in Myeloid-Derived Suppressor Cells

bioRxiv (Cold Spring Harbor Laboratory) · 2025-05-30

Sepsis survivors frequently develop long-term immune dysfunction, but the epigenetic mechanisms underlying persistent myeloid suppression remain unclear. Myeloid-derived suppressor cells (MDSCs), whose function is shaped by host age and sex, are key contributors to post-sepsis immune dysregulation. Here, we present a high-resolution epigenetic map targeting gene promoters of MDSCs after sepsis using MAPit-FENGC, a single-molecule assay that simultaneously profiles DNA methylation and chromatin accessibility. In a clinically relevant murine model including young and older adult male and female mice, splenic MDSCs were isolated for MAPit-FENGC and single-cell RNA sequencing. Unsupervised clustering identified nine promoter classes reflecting chromatin dynamics: age- and sex-dependent sepsis-induced opening (Classes 1-4), persistent closure with varying levels of DNA methylation (Classes 5-7), and constitutive openness post-sepsis (Classes 8, 9). Transcriptomic profiling corroborated these promoter states, linking accessibility with gene expression. These findings establish how epigenetic reprogramming of MDSCs may shape age- and sex-specific immune trajectories in sepsis survivors.

Functional connectivity within sensorimotor cortical and striatal regions is regulated by sepsis in a sex-dependent manner

NeuroImage · 2025-01-01 · 5 citations

• Using a surgical model of intra-abdominal sepsis, we examined the coupling between peripheral immune mechanisms, central neuroimmune activity, and functional network connectivity. • In female mice, systemic CD4 T-cell responses to sepsis were coupled with dorsal striatal microglial abundance and changes in functional connectivity in dorsal striatum and and somatosensory regions. • In male mice, systemic B cell and myeloid cell responses to sepsis involved astrocytosis in cortical, hippocampal, and dorsal striatal regions, which was coupled to similar alterations in functional connectivity in limbic prefrontal areas. • The results indicate sex-specific interactions between peripheral-central immune systems and brain functional networks that determine sepsis outcomes. Sepsis is a state of systemic immune dysregulation and organ failure that is frequently associated with severe brain disability. Epidemiological studies have indicated that younger females have better prognosis and clinical outcomes relative to males, though the sex-dependent response of the brain to sepsis during post-sepsis recovery remains largely uncharacterized. Using a modified polymicrobial intra-abdominal murine model of surgical sepsis, we characterized the acute effects of intra-abdominal sepsis on peripheral inflammation, brain inflammation and brain functional connectivity in young adult mice of both sexes. Following sepsis, both male and female mice survived the procedure, regained body weight within 7 days post-sepsis and showed reduced diversity in their gut microbiome. Interestingly, compared to the sepsis-induced changes observed in female mice, the post-septic male mice exhibited a comparatively robust profile of splenic cell expansion and intracerebral glial proliferation relative to their healthy counterparts. Analysis of resting-state functional Magnetic Resonance Imaging (fMRI) data collected from the post-septic mice revealed that while connectivity to the somatosensory cortex were affected equally in both sexes, intra-network connectivity strength in the striatum preferentially increased in post-septic males but remained near baseline in post-septic female mice. Additionally, the female mice showed reduced network connectivity alterations in the projections from periaqueductal gray to the superior colliculus as also between the anterior cingulate cortex and the striatum. Coupled with the sustained intracerebral gliosis response, the intra-striatal fMRI response patterns in males could signify a delayed recovery from sepsis. Together, our study provides evidence that peripheral sepsis influences peripheral immunity, brain immunity and brain connectivity in a sex-dependent manner, with the fMRI response strongly indicating cognitive benefits in young females recovering from sepsis relative to their male counterparts.