Biology subjects

Carter, B. M.

Publications and source records attributed to Carter, B. M..

4 recordsLinked to original sources

bioRxiv2026

Extrahepatic, cell-specific delivery of LNPs through competitive inhibition of ApoE-mediated uptake

Targeted lipid nanoparticles (LNPs) for extrahepatic drug delivery are limited by apolipoprotein E (ApoE)-mediated hepatic accumulation. We developed NanoPilot, a modular fusion protein platform comprising antibodies and anchors blocking the low density lipoprotein receptor (LDLR) ApoE binding site, to block LNP liver uptake and redirect to target cells. NanoPilot can be applied to preformulated LNPs in 10 minutes with two pipetting steps. In vitro, an anti-CD3{varepsilon} NanoPilot increased T-cell transfection 40-fold and reduced monocyte transfection 10-fold in human peripheral blood mononucleocytes. In immunocompetent mouse models, NanoPilot-coated LNPs achieved 30-40% splenic and hepatic T-cell transfection whilst bulk liver accumulation was reduced 3-fold. An anti-c-Kit NanoPilot was further shown to enhance delivery to a haematopoietic stem cell-like cell line in an in-vitro co-culture assay. NanoPilot establishes a versatile framework for the systemic delivery of genetic therapies through concomitant cell-specific targeting and off-target blocking. Further research will assess potential clinical applications.

biochemistry↗

bioRxiv2020

Targeting ischemia-induced KCC2 hypofunction rescues refractory neonatal seizures and mitigates epileptogenesis in a mouse model

Neonatal seizures pose a clinical challenge for their early detection, acute management, and mitigation of long-term comorbidities. A major cause of neonatal seizures is hypoxic-ischemic encephalopathy that results in seizures that are frequently refractory to the first-line anti-seizure medication phenobarbital (PB). One proposed mechanism for PB-inefficacy during neonatal seizures is the reduced expression and function of the neuron-specific K+/Cl- cotransporter 2 (KCC2), the main neuronal Cl- extruder that maintains chloride homeostasis and influences the efficacy of GABAergic inhibition. To determine if PB-refractoriness after ischemic neonatal seizures is dependent upon KCC2 hypofunction and can be rescued by KCC2 functional enhancement, we investigated the recently developed KCC2 functional enhancer CLP290 in a CD-1 mouse model of refractory ischemic neonatal seizures quantified with vEEG. We report that acute CLP290 intervention can rescue PB-resistance, KCC2 expression, and the development of epileptogenesis after ischemic neonatal seizures. KCC2 phosphorylation sites have a strong influence over KCC2 activity and seizure susceptibility in adult experimental epilepsy models. Therefore, we investigated seizure susceptibility in two different knock-in mice in which either phosphorylation of S940 or T906/T1007 was prevented. We report that KCC2 phosphorylation regulates both neonatal seizure susceptibility and CLP290-mediated KCC2 functional enhancement. Our results validate KCC2 as a clinically relevant target for refractory neonatal seizures and provide insights for future KCC2 drug development.

neuroscience↗

bioRxiv2020

Controlling protein nanocage assembly with hydrostatic pressure

Controlling the assembly and disassembly of nanoscale protein cages for the capture and internalisation of protein or non-proteinaceous components is fundamentally important to a diverse range of bionanotechnological applications. Here, we study the reversible, pressure-induced dissociation of a natural protein nanocage, E. coli bacterioferritin (Bfr), using synchrotron radiation small angle X-ray scattering (SAXS) and circular dichroism (CD). We demonstrate that hydrostatic pressures of 450 MPa are sufficient to completely dissociate the Bfr icositetramer into protein dimers, and the reversibility and kinetics of the reassembly process can be controlled by selecting appropriate buffer conditions. We also demonstrate that the heme B prosthetic group present at the subunit dimer interface influences the stability and pressure lability of the cage, despite its location being discrete from the inter-dimer interface that is key to cage assembly. This indicates a major cage-stabilising role for heme within this family of ferritins.

biophysics↗

bioRxiv2019

TrkB agonists prevent post-ischemic BDNF-TrkB mediated emergence of refractory neonatal seizures in CD-1 pups.

Refractory neonatal seizures do not respond to first-line anti-seizure medications (ASMs) like phenobarbital (PB), a positive allosteric modulator for GABAA receptors, the most widely used ASM to treat neonatal seizures. GABAA receptor-mediated inhibition is dependent upon neuronal chloride regulation. The electroneutral cation-chloride transporter KCC2 mediates neuronal chloride extrusion; an age-dependent increase of KCC2 expression enables the shift of GABAergic signaling from depolarizing to hyperpolarizing. BDNF-TrkB activation following excitotoxic injury recruits downstream targets like PLC{gamma}1, leading to KCC2 hypofunction. This study investigated the efficacy of partial and full TrkB agonists; LM22A-4 (LM), HIOC and Deoxygedunin (DG) respectively, on PB-refractory seizures, post-ischemic TrkB-pathway activation, and KCC2 membrane stability in a P7 CD-1 mouse model of refractory neonatal seizures. Anti-seizure efficacy was determined by quantifying seizure burdens with continuous video-EEG. LM rescued PB-refractory seizures in a sexually dimorphic manner. LM anti-seizure efficacy was associated with a significant reduction in the post-ischemic phosphorylation of TrkB at Y816, a site known to mediate post-ischemic KCC2 hypofunction via PLC{gamma}1 activation. LM additionally rescued ischemia-induced pKCC2-S940 dephosphorylation preserving its membrane stability. HIOC and DG, two novel full TrkB agonists, also rescued PB-refractoriness and post-ischemic TrkB-PLC{gamma}1 pathway activation. Additionally, chemogenetic inactivation of TrkB significantly reduced post-ischemic neonatal seizure burdens at P7. Developmental expression profiles of TrkB and KCC2 in naive pups identified developmental differences that may underlie the sex-dependent variance in anti-seizure efficacy. These results support a novel role for the TrkB receptor in the emergence of age-dependent refractory neonatal seizures.

neuroscience↗