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Hunter, G.

Publications and source records attributed to Hunter, G..

4 recordsLinked to original sources

Integrative Computational and Experimental Analysis of Curly Su Mutations in Drosophila melanogaster

The Curly Su (dMPO) protein, a homolog of the human myeloperoxidase (hMPO), is critical for wing development in Drosophila melanogaster. Like human peroxidases, dMPO is involved in various cellular and physiological processes, producing significant quantities of reactive oxygen species that contribute to both development and immunity in the fruit fly. Given the significant sequence and structural similarities between dMPO and hMPO, dMPO serves an ideal model for studying peroxidase functions and related pathologies. We performed saturated computational mutagenesis on dMPO, analyzing the effects of 11,191 missense mutations on its stability. Notably, the G378W mutation exhibited the greatest destabilizing effect, while the W621R, potentially pathogenic, also reduced dMPO stability. To investigate these effects in vivo, we used genome editing to generate the transgenic Drosophila with G378W, W621R, and deletion of residues 305-687. Remarkably, G378W mutants displayed significant alterations in wing morphology and reduced lifespan. RNA-seq analysis of transgenic and wild-type flies revealed differentially expressed genes (DEGs), as interpreted through gene ontology analysis. Our integrated computational and genetic approach identified dMPO mutations that disrupt protein stability and alter gene expression. These findings offer new insight into how single-point mutations can lead to systemic biological changes. Author SummaryProteins are the molecular machines that drive almost every process in living organisms, and even small genetic changes can disrupt their structure and function. In this study, we focused on Curly Su, a protein in fruit flies that is similar to human myeloperoxidase. We used a computational approach called saturation mutagenesis to model over 11,000 possible single mutations in the Curly Su protein and predict how they would affect its stability. We then used genome editing to introduce several destabilizing and potential disease-causing mutations into flies. These mutant flies developed abnormal wings, had shorter lifespans, and showed widespread changes in gene activity, particularly in metabolism and immune pathways. By combining computational predictions with experimental validation, our work demonstrates a powerful and generalizable strategy for linking specific genetic mutations to whole-organism outcomes. This approach not only sheds light on the biological role of Curly Su but also provides a framework that can be applied to other genes and organisms, offering insights relevant to human health and disease.

bioinformatics↗

Heme overdrive rewires pan-cancer cell metabolism

Porphyrin overdrive rewires pan-cancer cell metabolismAll cancer cells reprogram metabolism to support aberrant growth. Here, we report that cancer cells employ and depend on imbalanced and dynamic heme metabolic pathways for their oncogenic growth. We coined this essential metabolic rewiring porphyrin overdrive and determined that it is cancer-universal, cancer-essential, and cancer-specific. While porphyrin overdrive is absent in differentiated cells or somatic stem cells, it is present in patient-derived tumor progenitor cells, demonstrated by single cell RNAseq, and in early embryogenesis. Among the major drivers are proteins involved in biosynthesis of heme intermediates and heme trafficking. CRISPR/Cas9 editing to engineer leukemia cells with impaired heme biosynthetic steps confirmed our whole genomic data analyses that porphyrin overdrive is linked to oncogenic states and cellular differentiation. In conclusion, we identified a dependence of cancer cells on non-homeostatic heme metabolism, and we targeted this cancer metabolic vulnerability with a novel "bait-and-kill" strategy to eradicate malignant cells. One-Sentence SummaryPorphyrin overdrive reprograms cancer cellular metabolism.

cancer biology↗

Ipsilesional motor cortex activation with high-force unimanual handgrip contractions of the less-affected limb in participants with stroke

Stroke is a leading cause of severe disability that often presents with unilateral motor impairment. Conventional rehabilitation approaches focus on motor practice of the affected limb and aim to suppress brain activity in the contralesional hemisphere to facilitate ipsilesional hemispheric neuroplasticity subserving motor recovery. Previous research has also demonstrated that exercise of the less-affected limb can promote motor recovery of the affected limb through the interlimb transfer of the trained motor task, termed cross-education. One of the leading theories for cross-education proposes that the interlimb transfer manifests from ipsilateral cortical activity during unimanual motor tasks, and that this ipsilateral cortical activity results in motor related neuroplasticity giving rise to contralateral improvements in motor performance. Conversely, exercise of the less-affected limb promotes contralesional brain activity which is typically viewed as contraindicated in stroke recovery due to the interhemispheric inhibitory influence onto the ipsilesional hemisphere. High-force unimanual handgrip contractions are known to increase ipsilateral brain activation in control participants, but it remains to be determined if this would be observed in participants with stroke. Therefore, this study aimed to determine how parametric increases in handgrip force during repeated contractions with the less-affected limb impacts brain activity bilaterally in participants with stroke and in a cohort of neurologically intact controls. In this study, higher force contractions were found to increase brain activation in the ipsilesional/ipsilateral hemisphere in both groups (p = .002), but no between group differences were observed. These data suggest that high-force exercise with the less-affected limb may promote ipsilesional cortical plasticity to promote motor recovery of the affected-limb in participants with stroke.

neuroscience↗

Long-range Notch-mediated tissue patterning requires actomyosin contractility

Dynamic, actin-based protrusions function in cell-cell signaling in a variety of systems. In the dorsal thorax of the developing fly, basal protrusions enable non-neighboring epithelial cells to touch, extending the range over which Notch-mediated lateral inhibition can occur during bristle patterning. Given that actin-based cell protrusions can exert mechanical forces on their environment and Notch receptor activation is mechanically sensitive, how might cytoskeletal contractility contribute to Notch signaling? We identify a pool of basal non-muscle myosin II (myosin II) that regulates protrusion dynamics, promotes Notch signaling, and is required in signal sending and receiving cells for Notch-dependent patterning. We show that interactions between protrusions are extensive and subject to actomyosin contractility. The effects of reducing myosin II activity are more pronounced for protrusion-mediated signaling than for signaling at lateral cell contacts. Together, these results reveal a role for actomyosin contractility in Notch activation, signaling, and patterning in a developmental context.

developmental biology↗