Biology subjects

Okafor, A.

Publications and source records attributed to Okafor, A..

3 recordsLinked to original sources

bioRxiv2026

In vivo Proximity & Spatial Proteomics with CRISPR Screening Identify STXBP1 as a Protective Modifier of a-synuclein Toxicity in Dopamine Neurons.

Parkinsons disease (PD) is a disease of adults involving the loss of dopaminergic neurons after a long, asymptomatic, prodromal period. -synuclein, LRRK2, and VPS35 are linked to familial PD, however, how these mutations predispose dopamine neurons to death during the early prodromal phases remains unclear. Here, we used in vivo native proximity proteomics (iBioID) and dopaminergic neuron-specific subcellular proteomics across multiple PD models to uncover early alterations preceding neuronal loss. Our analyses identified convergent disruptions in synaptic protein abundance, indicating that presynaptic trafficking defects are early events in PD pathogenesis. Using a targeted CRISPR-based genetic screen in dopamine neurons, we demonstrated that mimicking this misregulation of STXBP1 amplifies vulnerability to -synuclein, implicating it as a previously underappreciated toxicity buffering factor. These findings highlight convergent mechanisms that sensitize dopamine neuronal degeneration and that presynaptic vesicle SNARE-complex proteins could serve as key targets for disease-modifying therapies in PD and related neurodegenerative disorders. HighlightsO_LIIn vivo native-BioID mapping of multiple Parkinsons disease (PD) protein interactomes revealed a convergent presynaptic network. C_LIO_LIiBioID analysis on mutant PD proteins (-synuclein A30P, LRRK2 G2019S, VPS35 D620N) uncovered mutation-specific shifts in local proximity networks, notably in endocytic and vesicle recycling pathways. C_LIO_LISpatial proteomics (iBioCoFrac) of dopamine neurons in vivo identified functional modules with reduced levels of key synaptic proteins in PD models. C_LIO_LIComparative proteomics using iBioCoFrac revealed synaptic vesicle regulation as a primary site of molecular convergence and early molecular signatures in dopamine neurons across multiple PD mouse models. C_LIO_LIAn in vivo CRISPR screen pinpointed the presynaptic protein Stxbp1/Munc18-1 as an -synuclein toxicity modifier in dopaminergic neurons. C_LI

neuroscience↗

bioRxiv2024

Transcriptome analysis reveals a novel DNA element that may interact with chromatin-associated proteins in Plasmodium berghei during erythrocytic development

BackgroundThe life cycle of Plasmodium parasites is intricate and multistage, alternating between dynamic environments. Temporal regulation of transcription by stage-specific transcription factor binding at particular regulatory regions within gene promoters facilitates its progression. As a result, each new developmental stage is endowed with its unique gene sets, whose just-in-time expression enables the parasite to completely adapt to the necessary circumstances. Our understanding of these transcriptome-level regulatory processes is limited, and more so, a thorough examination of the entire life cycle in the experimentally tractable rodent model organism P. berghei is lacking. ResultsWe performed a genome-wide analysis of RNA-Seq data from different developmental stages of P. berghei. Integrated data from the human malaria parasites P. falciparum and P. vivax demonstrated that Plasmodium parasites have a unique transcriptional signature. We identified the sets of genes differentially expressed at each stage, clustered them based on similarities of their expression profiles, and predicted the regulatory motifs governing their expression. We interpreted the motifs using known binding sites for established eukaryotic transcription factors, including those of the ApiAP2s, and identified eight potentially novel motifs. Additionally, we expanded the annotation of another motif--AGGTAA--found in genes exclusive to erythrocytic development and identified members of the PfMORC and GCN5 complexes among its possible interacting proteins. ConclusionThis study provides new insights into gene usage and its regulation during P. berghei development.

bioinformatics↗

bioRxiv2023

UBE2N is essential for maintenance of skin homeostasis and suppression of inflammation

UBE2N, a Lys63-ubiquitin conjugating enzyme, plays critical roles in embryogenesis and immune system development and function. However, its roles in adult epithelial tissue homeostasis and pathogenesis are unclear. We generated conditional mouse models that deleted Ube2n in skin cells in a temporally and spatially controlled manner. We found that Ube2n- knockout (KO) in the adult skin keratinocytes induced a range of inflammatory skin defects characteristic of psoriatic and actinic keratosis. These included eczematous inflammation, epidermal and dermal thickening, parakeratosis, and increased immune cell infiltration, as well as signs of edema and blistering. Single cell transcriptomic analyses and RT-qPCR showed that Ube2n KO keratinocytes expressed elevated myeloid cell chemo-attractants such as Cxcl1 and Cxcl2 and decreased the homeostatic T lymphocyte chemo-attractant, Ccl27a. Consistently, the infiltrating immune cells of Ube2n-KO skin were predominantly myeloid-derived cells including neutrophils and M1-like macrophages that were highly inflammatory, as indicated by expression of Il1{beta} and Il24. Pharmacological blockade of the IL-1 receptor associated kinases (IRAK1/4) alleviated eczema, epidermal and dermal thickening, and immune infiltration of the Ube2n mutant skin. Together, these findings highlight a key role of keratinocyte-UBE2N in maintenance of epidermal homeostasis and skin immunity and identify IRAK1/4 as potential therapeutic target for inflammatory skin disorders.

pathology↗