Biology subjects

Denton, H.

Publications and source records attributed to Denton, H..

4 recordsLinked to original sources

bioRxiv2026

Oxidative Stress Susceptibility, Complement Dysregulation, and Metabolic Reprogramming in CFH Y402H Patient-Derived Choriocapillaris Endothelial Cells

Age-related macular degeneration (AMD) is a leading cause of central vision loss. Immunofluorescence and gene expression studies in human donor eyes have shown that choriocapillaris endothelial cells (CECs) are lost before retinal pigment epithelium (RPE) degeneration, leaving extracellular matrix-filled empty lumens known as "ghost vessels." To investigate disease mechanisms, we generated CECs from patient-specific induced pluripotent stem cells (iPSCs) carrying the high-risk CFH Y402H variant and CRISPR-Cas9-corrected isogenic controls. The iPSC-derived CECs expressed canonical endothelial markers, formed fenestrations, maintained barrier function, and assembled capillary-like structures. Although baseline metabolism was preserved, Y402H CECs showed heightened sensitivity to hydroquinone-induced oxidative stress, with increased cytotoxicity and deposition of the complement membrane attack complex (C5b-9). RNA sequencing revealed oxidative stress-driven upregulation of lipid biosynthesis, mTORC signalling, endothelial-to-mesenchymal transition, and angiogenic pathways, alongside an imbalance in the complement pathway. These findings demonstrate that the CFH Y402H polymorphism increases CEC vulnerability to environmental stress, linking complement dysregulation and metabolic reprogramming to choriocapillaris dysfunction in AMD and highlighting CECs as a potential therapeutic target.

Cell Biology↗

bioRxiv2025

Neuronal differentiation enhances a cytoplasmic pool of tousled-like kinase 2 (TLK2)

Mental retardation autosomal dominant 57 (MRD57) is a rare neurodevelopmental disorder characterised by delayed language and psychomotor development, intellectual disability, hypotonia, gastrointestinal issues and facial dysmorphia. It is linked to genetic mutations in the serine/threonine kinase TLK2, characterised by haploinsufficiency and in some cases, its loss or impaired kinase function. TLK2 is an established cell cycle regulator that has been extensively studied in mitotic cells. It is upregulated in cancers, driving tumour growth, however, the role of TLK2 in postmitotic neurons is not understood. We therefore aimed to gain insight into how TLK2 mutations cause MRD57 by determining where TLK2 is expressed in the brain and its subcellular localisation during neuronal differentiation. Public human and mouse brain transcriptomic data revealed splice variant diversity in the N-terminus of TLK2, which contains its nuclear localisation sequence (NLS). Using splice-specific in situ hybridisation probes, we observed expression of TLK2 isoforms that contain and lack the NLS in the mouse hippocampus and cerebellum. We confirmed these findings in human SH-SY5Y neuroblastoma cells, and found that neuronal differentiation of these cells enhances a cytoplasmic pool of TLK2 by two mechanisms: nuclear export of full length TLK2 and increased expression of TLK2 splice variants lacking the NLS. Finally, acute stimuli that mimic synaptic activity were sufficient to elicit nuclear export of TLK2. Our data highlight the need to establish the neuronal cytoplasmic substrates of TLK2 and determine how the loss of TLK2 activity in MRD57 might impact their function in the developing and mature brain.

neuroscience↗

bioRxiv2024

The Alzheimers Disease Risk Genes MS4A4A And MS4A6A Cooperate to Negatively Regulate Trem2 and Microglia states

Genetic variations in MS4A4A and MS4A6A are linked to the regulation of cerebrospinal fluid soluble TREM2 (sTREM2) levels and are associated with Alzheimers disease (AD) risk and progression. Using CRISPR knockout and MS4A4A-degrading antibodies in primary human microglia, non-human primates (NHP), and a xenotransplantation model of amyloid pathology, we provide evidence that MS4A4A and MS4A6A are negative regulators of both the transmembrane and soluble TREM2 proteins. They also negatively regulate microglia proliferation, survival, metabolism, lysosomal function, energetics, phagocytosis, and disease-fighting states. Mechanistically, we find that MS4A4A exerts negative regulation by interacting with MS4A6A and protecting it from degradation. MS4A6A in turn forms a complex with and blocks the co-receptor DAP12, which is required for the stability, cell surface localization, and signaling of TREM2 and other receptors. Taken together, the data indicate that MS4A4A and MS4A6A are cooperating, post-transcriptional negative regulators of TREM2 and microglial function, and potential drug targets for AD.

neuroscience↗

bioRxiv2018

Utilisation of staphylococcal immune evasion protein Sbi as a novel vaccine adjuvant

Co-ligation of the B cell antigen receptor with complement receptor 2 on B-cells via a C3d-opsonised antigen complex significantly lowers the threshold required for B cell activation. Consequently, fusions of antigens with C3d polymers have shown great potential in vaccine design. However, these linear arrays of C3d multimers do not mimic the natural opsonisation of antigens with C3d. Here we investigate the potential of using the unique complement activating characteristics of Staphylococcal immune-evasion protein Sbi to develop a pro-vaccine approach that spontaneously coats antigens with C3 degradation products in a natural way. We show that Sbi rapidly triggers the alternative complement pathway through recruitment of complement regulators, forming a tripartite complex that acts as a competitive antagonist of factor H, resulting in enhanced complement consumption. These functional results are corroborated by the structure of this complement activating Sbi-III-IV:C3d:FHR-1 complex. Finally, we demonstrate that Sbi, fused with Mycobacterium tuberculosis antigen Ag85b, causes efficient opsonisation with C3 fragments, thereby enhancing the immune response significantly beyond that of Ag85b alone, providing proof of concept for our pro-vaccine approach.

biochemistry↗