Biology subjects

Cole, D. C.

Publications and source records attributed to Cole, D. C..

5 recordsLinked to original sources

bioRxiv2025

Cyfip2 mediates sensorimotor integration of visual input through Rac1-dependent actin remodeling

Sensorimotor integration of visual input is essential for adaptive behaviors such as navigation, hunting, and escape from danger, yet our understanding of the developmental mechanisms that assemble these visuomotor circuits remains incomplete. Cytoplasmic FMRP-interacting protein 2 (cyfip2) is a key factor in retinotectal axon guidance in zebrafish larvae, and it has conserved roles in regulating actin dynamics and mRNA translation. Variants in human CYFIP2 cause neurodevelopmental disabilities including vision deficits, but how it functions to shape visually-driven behavior is unclear. Here we measured multiple visually-mediated behaviors, brain-wide activity, and conditional rescue of behavioral defects in larval zebrafish to define cyfip2s roles in assembling visual sensorimotor circuits. cyfip2 mutants display severe deficits in prey capture and dark and light flash responses, despite normal optokinetic responses, indicating intact retinal phototransduction but disrupted downstream sensorimotor integration. Both spontaneous and stimulus-evoked neuronal activity are reduced in the optic tectum of cyfip2 mutants, as measured by phospho-ERK immunostaining and pan-neuronal calcium, consistent with impaired functional input from retinal ganglion cells. Finally, using conditional transgenic alleles to temporally control Cyfip2 expression, we identified a critical window from 30-50 hours post-fertilization during which Cyfip2 acts through Rac1-dependent actin polymerization but not FMRP-mediated translation to establish visual behavior circuits. Together, these findings define how and when Cyfip2 acts as a critical organizer of vertebrate visual circuit development, providing mechanistic insight into the visual and motor deficits in human subjects with variants in CYFIP2.

neuroscience↗

bioRxiv2025

Multi-omic analyses identify molecular targets of Chd7 that mediate CHARGE syndrome model phenotypes

CHARGE syndrome is a developmental disorder that affects 1 in 10,000 births, and patients exhibit both physical and behavioral characteristics. De novo mutations in CHD7 (chromodomain helicase DNA binding protein 7) cause 67% of CHARGE syndrome cases. CHD7 is a DNA-binding chromatin remodeler with thousands of predicted binding sites in the genome, making it challenging to define molecular pathways linking loss of CHD7 to CHARGE phenotypes. To address this problem, here we used a previously characterized zebrafish CHARGE model to generate transcriptomic and proteomic datasets from larval zebrafish head tissue at two developmental time points. By integrating these datasets with differential expression, pathway, and upstream regulator analyses, we identified multiple consistently dysregulated pathways and defined a set of candidate genes that link loss of chd7 with disease-related phenotypes. Finally, to functionally validate the roles of these genes, CRISPR/Cas9-mediated knockdown of capgb, nefla, or rdh5 phenocopies behavioral defects seen in chd7 mutants. Our data provide a resource for further investigation of molecular mediators of CHD7 and a template to reveal functionally relevant therapeutic targets to alleviate specific aspects of CHARGE syndrome. Summary StatementWe have identified Chd7 target genes capgb, nefla, and rdh5 that mediate CHARGE model phenotypes from transcriptomic and proteomic analysis of chd7 wild type, heterozygous, and homozygous mutant zebrafish brain tissue at two developmental time points.

neuroscience↗

bioRxiv2023

Cyfip2 controls the acoustic startle threshold through FMRP, actin polymerization, and GABAB receptor function.

Animals process a constant stream of sensory input, and to survive they must detect and respond to dangerous stimuli while ignoring innocuous or irrelevant ones. Behavioral responses are elicited when certain properties of a stimulus such as its intensity or size reach a critical value, and such behavioral thresholds can be a simple and effective mechanism to filter sensory information. For example, the acoustic startle response is a conserved and stereotyped defensive behavior induced by sudden loud sounds, but dysregulation of the threshold to initiate this behavior can result in startle hypersensitivity that is associated with sensory processing disorders including schizophrenia and autism. Through a previous forward genetic screen for regulators of the startle threshold a nonsense mutation in Cytoplasmic Fragile X Messenger Ribonucleoprotein (FMRP)-interacting protein 2 (cyfip2) was found that causes startle hypersensitivity in zebrafish larvae, but the molecular mechanisms by which Cyfip2 establishes the acoustic startle threshold are unknown. Here we used conditional transgenic rescue and CRISPR/Cas9 to determine that Cyfip2 acts though both Rac1 and FMRP pathways, but not the closely related FXR1 or FXR2, to establish the acoustic startle threshold during early neurodevelopment. To identify proteins and pathways that may be downstream effectors of Rac1 and FMRP, we performed a candidate-based drug screen that indicated that Cyfip2 can also act acutely to maintain the startle threshold branched actin polymerization and N-methyl D-aspartate receptors (NMDARs). To complement this approach, we used unbiased discovery proteomics to determine that loss of Cyfip2 alters cytoskeletal and extracellular matrix components while also disrupting oxidative phosphorylation and GABA receptor signaling. Finally, we functionally validated our proteomics findings by showing that activating GABAB receptors, which like NMDARs are also FMRP targets, restores normal startle sensitivity in cyfip2 mutants. Together, these data reveal multiple mechanisms by which Cyfip2 regulates excitatory/inhibitory balance in the startle circuit to control the processing of acoustic information.

neuroscience↗

bioRxiv2022

Structure-guided synthesis of FK506 and FK520 analogs with increased selectivity exhibit in vivo therapeutic efficacy against C. neoformans

Calcineurin is an essential virulence factor that is conserved across human fungal pathogens including Cryptococcus neoformans, Aspergillus fumigatus, and Candida albicans. Although an excellent target for antifungal drug development, the serine-threonine phosphatase activity of calcineurin is conserved in mammals and inhibition of this activity results in immunosuppression. FK506 (tacrolimus) is a naturally produced macrocyclic compound that inhibits calcineurin by binding to the immunophilin FKBP12. Previously, our fungal calcineurin-FK506-FKBP12 structure-based approaches identified a non-conserved region of FKBP12 that can be exploited for fungal-specific targeting. These studies led to the design of an FK506 analog, APX879, modified at the C22 position that was less immunosuppressive yet maintained antifungal activity. We now report high resolution protein crystal structures of fungal FKBP12 and a human truncated calcineurin-FKBP12 bound to a natural FK506 analog, FK520 (ascomycin). Based on information from these structures and the success of APX879, we synthesized and screened a novel panel of C22-modified compounds derived from both FK506 and FK520. One compound, JH-FK-05 demonstrates broad-spectrum antifungal activity in vitro and is non-immunosuppressive in vivo. In murine models of pulmonary and disseminated C. neoformans infection, JH-FK-05 treatment significantly reduced fungal burden and extended animal survival alone and in combination with fluconazole. Furthermore, molecular dynamic simulations performed with JH-FK-05 binding to fungal and human FKBP12 identified additional residues outside of the C22 and C21 positions that could be modified to generate novel FK506 analogs with improved antifungal activity. SignificanceDue to rising rates of antifungal drug resistance and a limited armamentarium of antifungal treatments, there is a paramount need for novel antifungal drugs to treat systemic fungal infections. Calcineurin has been established as an essential and conserved virulence factor in several fungi, making it an attractive antifungal target. However, due to the immunosuppressive action of calcineurin inhibitors, they have not been successfully utilized clinically for antifungal treatment in humans. Recent availability of crystal structures of fungal calcineurin bound inhibitor complexes have enabled the structure-guided design of FK506 analogs and led to a breakthrough in the development of a compound increased for fungal specificity. The development of a calcineurin inhibitor with reduced immunosuppressive activity and therapeutic antifungal activity would add a significant tool to the treatment options for these invasive fungal infections with exceedingly high rates of mortality.

microbiology↗

bioRxiv2020

Glutamatergic adaptation to stress in medial prefrontal cortex underlies risk and resilience for pessimistic beliefs

Stress is a major risk factor for the development of mental illness, including major depressive disorder (MDD), yet the underlying biological mechanisms remain unclear. Particular challenges lie in disentangling adaptive versus maladaptive responses to repeated stress exposure. Preclinically, stress-induced changes in glutamatergic function have been frequently observed in the medial prefrontal cortex (mPFC), a key region for mediating adaptive stress responses. Here, we examined stress-induced changes in mPFC glutamate using magnetic resonance spectroscopy (MRS) in four human samples varying in perceived stress exposure. Changes in mPFC glutamate following an acute stressor were reliably moderated by recent perceived stress in healthy controls. This adaptive glutamate response was absent in unmedicated individuals with MDD and was associated with excessively pessimistic beliefs as assessed via ecological momentary assessments over a 1-month follow-up period. Taken together, these data provide novel evidence for glutamatergic adaptation to stress in mPFC that is significantly disrupted in MDD.

neuroscience↗