Biology subjects

Robertson, C. L.

Publications and source records attributed to Robertson, C. L..

4 recordsLinked to original sources

bioRxiv2026

Rapid Intracellular Delivery of Human Heat Shock Protein 72 Prevents Memory Loss and Inhibits Neurodegeneration up to 9 Days After a Blast Injury

Traumatic brain injuries (TBIs) are increasingly prevalent among military service members and are associated with long-term neurological impairment and neurodegeneration. Heat shock protein 72 (HSP72) has demonstrated cytoprotective properties and has been shown to cross the blood brain barrier in rat models of blast injury, remaining in brain tissue for up to 12 hours. In this study, we evaluate engineered Fv-HSP72 variants for their ability to reduce neurodegeneration and preserve short-term memory following blast-induced TBI. Male Sprague-Dawley rats were assigned to 9 groups of n = 8 rats. Animals were either not exposed to blast (Sham), exposed to blast (Blast Only), blast exposed and given buffer (Vehicle), or blast exposed and treated with one of three Fv-HSP72 variants, dosed at 10 or 30mg/kg at 15m post-blast. Blast exposure was generated using an Advanced Blast Simulator (ABS) producing positive static pressure to model moderate to severe blast injury. Animals were euthanized 48 hours post injury for neurodegeneration and immunologic biomarker analysis. After selecting an effective Fv-HSP72 variant using the biomarker data, additional rats were divided into Sham, Vehicle, and Fv-HSP72 treatment groups to evaluate short-term memory function through the Novel Object Recognition (NOR) test on days 2 and 8 post-blast. Analysis of cortical and spinal cord tissues demonstrated a statistically significant reduction in expression of neurodegenerative markers of Tau phosphorylation and glial injury (GFAP) for rats receiving a single dose of our clinical candidate, RBB012-CTB. In fact, the drug drove astrogliosis toward a neuroprotective state in blast exposed rats. In the NOR assay, Fv-HSP72 treated rats showed improved recognition performance, indicating preservation of short-term memory function. With similar biomarker results obtained for a controlled cortical impact injury model published elsewhere (Chan et al. manuscript submitted), the analyses suggest Fv-HSP72 is neuroprotective following a blast injury as well. One sentence summaryThis study describes the effectiveness of a biologic agent, Fv-HSP72, in significantly preventing learning and memory loss in rats for up to 9 days after a blast injury.

neuroscience↗

bioRxiv2026

Rapid Intracellular Delivery of Human Heat Shock Protein 72 Inhibits Neurodegeneration and Oxidative Damage After a Traumatic Brain Injury

Fv-HSP72 is a rapid cell-penetrating human heat shock protein for the treatment of traumatic organ injuries. We have shown this re-engineered protein (HSP72) is capable of crossing the blood brain barrier (BBB) of rats suffering a controlled cortical impact (CCI) and remains in brain tissue for up to 12 hours; long after clearance from the cortex of uninjured rats. Peptide sequences unique to Fv-HSP72 allow for its differential detection from endogenous HSP72. Male Sprague-Dawley rats were divided into 10 groups of n=10 with those animals receiving a CCI subjected to a unilateral cortical contusion simulating a moderate to severe brain injury using an electronically controlled pneumatic impact device. Control groups were either uninjured (Sham), injured (TBI Only), or injured and given buffer (TBI+Vehicle). Rats treated with one of three Fv-HSP72 variants were dosed at 10 or 30mg/kg 15m post-impact, then sacrificed 48 hours later. Cortical tissues were extracted from the ipsilateral and contralateral hemispheres for biomarker analysis. Here we report results of our drug inhibiting neurodegeneration based on five biomarkers (NF-L, pNF-H, pTau [T181, T231, S396]). These results were statistically significant, especially for one of the Fv-HSP72 variants, when comparing differences both between treatment groups and within groups (i.e. when comparing ipsi-vs. contralateral hemispheres). Significant inhibition of oxidative stress (3-NT) and inflammatory (IL-6) biomarkers were also observed (both p<0.0001). With similar results obtained for a blast injury model being published elsewhere, the analyses suggest Fv-HSP72 is neuroprotective following a direct impact brain injury. One sentence summaryThis study describes the effectiveness of a biologic agent, Fv-HSP72, in significantly inhibiting neuronal tissue damage in the brain when administered after a direct cortical impact.

neuroscience↗

bioRxiv2025

CRABS-ROC, A Respirometry Protocol For Overcoming Substrate Limitations, Reveals Excess Brain Mitochondrial Complex I Capacity

Mitochondrial bioenergetic competency in cells is frequently assessed by the Mito Stress Test protocol, which includes uncoupler addition for evaluating respiratory capacity. The uncoupled oxygen consumption rate (OCR) is usually defined as maximal respiration, with little consideration of whether the measured rate is restricted by substrate supply. In this study, we show that the uncoupled OCR is substrate-limited in rat primary cortical neurons and isolated mouse forebrain synaptosomes. We use a different respirometry protocol we name CRABS-ROC (Complex Respirometry Assay Bypassing Substrate-Restricted Oxygen Consumption) that enables evaluation of individual electron transport chain (ETC) complex capacity using saturating levels of substrate to bypass this restriction. Applying CRABS-ROC to primary cortical neurons reveals >2-fold excess Complex I capacity beyond the uncoupled OCR of cells metabolizing glucose and pyruvate. Furthermore, we demonstrate that CRABS-ROC can expose a Complex I deficit in isolated harlequin mutant brain mitochondria that display wild-type levels of Complex I-substrate-linked respiration despite having about half the normal level of Complex I. Thus, CRABS-ROC should be broadly useful for studies on mitochondrial function because it can both reveal excess ETC capacity and unmask ETC alterations that may be missed by the most widely used methods.

cell biology↗

bioRxiv2025

Idebenone Enhances the Early Microglial Response to Traumatic Brain Injury and Mitigates Acute Gene Expression Changes to Ephrin-A and Dopamine Signaling Pathways

Traumatic Brain Injury (TBI) leads to persistent pro-inflammatory microglial activation implicated in neurodegeneration. Idebenone, a coenzyme Q10 analogue that interacts with both mitochondria and the tyrosine kinase adaptor SHC1, inhibits aspects of microglial activation in vitro. We used the NanoString Neuropathology panel to test the hypothesis that idebenone post-treatment mitigates TBI pathology-associated acute gene expression changes by moderating the pro-inflammatory microglial response to injury. Controlled cortical impact to adult male mice increased the microglial activation signature in peri-lesional cortex at 24 hours post-TBI. Unexpectedly, several microglial signature genes upregulated by TBI were further increased by post-injury idebenone administration. However, idebenone significantly attenuated TBI-mediated perturbations to gene expression associated with behavior, particularly in the gene ontology:biological process (GO:BP) pathways "ephrin receptor signaling" and "dopamine metabolic process." Gene co-expression analysis correlated levels of microglial complement component 1q (C1q) and the neurotrophin receptor gene Ntrk1 to large (>3-fold) TBI-induced decreases in dopamine receptor genes Drd1 and Drd2 that were mitigated by idebenone treatment. Bioinformatics analysis identified SUZ12 as a candidate transcriptional regulator of idebenone-modified gene expression changes. Overall, results suggest that idebenone enhances TBI-induced microglial proliferation within the first 24 hours of TBI and identify Ephrin-A and dopamine signaling as novel idebenone targets.

neuroscience↗