Biology subjects

Abbey, M.

Publications and source records attributed to Abbey, M..

4 recordsLinked to original sources

bioRxiv2026

Neuroinflammation and metabolic dysfunction in POLG-related mitochondrial epilepsy

Super-refractory status epilepticus is a common neurological manifestation of mitochondrial disease caused by bi-allelic pathogenic variants in POLG. Epilepsy in POLG-related disease typically presents with an explosive onset of status epilepticus, often from an occipital focus, and is associated with extensive neurodegeneration. The neuropathological mechanisms underlying POLG-related mitochondrial epilepsy remain poorly understood, however, neuroinflammation and glial dysfunction are hypothesised to play a significant role. In this study, we performed a neuropathological and proteomic investigation of post-mortem brain tissues from 12 patients with POLG-related mitochondrial epilepsy (age range: 3 - 28 years) and matched control cases. Given that the primary visual cortex is prominently involved in this epileptic disorder, occipital cortical tissues (Brodmann area 17) were compared to frontal cortical tissues (Brodmann area 9). Liquid chromatography-mass spectrometry (LC-MS/MS) analysis identified a distinct immunometabolic signature in the occipital cortex, and to a lesser extent in the frontal cortex, in POLG-related epilepsy. This was characterised by decreased abundance of mitochondrial proteins coupled to an increased expression of innate immune and inflammatory proteins, consistent with neuroinflammation. To validate these observations, we confirmed an increased density of cells immunoreactive for acute phase proteins (C-reactive protein, osteopontin and serpin A3), immune co-receptors (CD14 and HLA-DR), the inflammatory glycoprotein YKL40, the cytokine TNF-alpha, and mitochondrial translocator protein (TSPO). We also demonstrate a decreased expression of mitochondrial oxidative phosphorylation (OXPHOS) subunits within POLG patient microglia, indicative of mitochondrial dysfunction. Finally, we show enrichment of mitochondrial OXPHOS and interneuron proteins in the control primary visual cortex compared with the frontal cortex, which may underlie the selective regional vulnerability observed in POLG-related mitochondrial disease. Overall, these findings provide strong neuropathological evidence implicating neuroinflammation and glial dysfunction in POLG-related epilepsy.

neuroscience↗

bioRxiv2025

Septin7 is essential in early hematopoiesis, but redundant at later stages

The unique cytoskeletal protein Septin7 is generally considered to be required for cytokinesis in yeast and mammals. Whole body genetic ablation of Septin7 in mice is embryonic lethal. Septin7-deficient fibroblasts and HeLa cells are defective in cytokinesis and undergo obligate multinucleation. Surprisingly, lymphocyte- and myeloid-specific deletion of Septin7 in mice did not result in any detectable abnormalities in blood lineage development, suggesting that Septin7 is dispensable for steady-state hematopoiesis. In contrast, Septin7-deficient hematopoietic stem cells failed to engraft and establish donor chimerism following transplantation, indicating that Septin7 is essential for hematopoietic stem cell function under stress conditions. To reconcile these contradictory findings, we analyzed the effects of Septin7 deletion in hematopoietic cells from mice with either pan-hematopoietic or lymphoid lineage-specific Septin7 deletion. Our results demonstrate that Cre-induced deletion of the floxed Septin7 allele is inefficient during the early stages of hematopoiesis, suggesting strong selection pressure against Septin7 deficiency at this stage. In contrast, deletion of Septin7 at the common lymphoid progenitor stage, as well as in Hoxb8-immortalized hematopoietic progenitors, is efficient and does not result in any noticeable defects in cell division. Taken together, our findings indicate that Septin7 is essential during early hematopoiesis but becomes dispensable at later stages.

biochemistry↗

bioRxiv2022

Discovery of small molecule antagonists of human Retinoblastoma Binding Protein 4 (RBBP4)

RBBP4 is a nuclear WD40 motif-containing protein widely implicated in various cancers and a putative drug target. It interacts with multiple proteins within diverse complexes such as nucleosome remodeling and deacetylase (NuRD) complex and polycomb repressive complex 2 (PRC2), as well as histone H3 and H4 through two distinct binding sites. B-cell lymphoma/leukemia 11A (BCL11A), friend of GATA-1 (FOG-1), plant homeodomain finger protein 6 (PHF6) and histone H3 bind to the top of the donut-shaped seven-bladed {beta}-propeller fold of RBBP4, while suppressor of zeste 12 (SUZ12), metastasis associated protein 1 (MTA1) and histone H4 bind to a pocket on the side of the WD40 repeats of this protein. Here, we report the discovery of the first small molecule antagonists of the RBBP4 top pocket, competing with interacting peptides from proteins such as BCL11A and histone H3. We also determined the first crystal structure of RBBP4 in complex with a small molecule (OICR17251), paving the path for structure-guided design and optimization towards more potent antagonists.

biochemistry↗

bioRxiv2018

Targeting Human Retinoblastoma Binding Protein 4 (RBBP4) and 7 (RBBP7)

RBBP4 and RBBP7 (RBBP4/7) are highly homologous nuclear WD40 motif containing proteins widely implicated in various cancers and are valuable drug targets. They interact with multiple proteins within diverse complexes such as NuRD and PRC2, as well as histone H3 and H4 through two distinct binding sites. FOG-1, PHF6 and histone H3 bind to the top of the donut shape seven-bladed {beta}-propeller fold, while SUZ12, MTA1 and histone H4 bind to a pocket on the side of the WD40 repeats. Here, we briefly review these six interactions and present binding assays optimized for medium to high throughput screening. These assays enable screening of RBBP4/7 toward the discovery of novel cancer therapeutics.

biochemistry↗