Biology subjects

Crowley, N.

Publications and source records attributed to Crowley, N..

3 recordsLinked to original sources

bioRxiv2025

Tryptophan and IFN-γ Differentially Modulate Cellular Uptake, Intracellular Trafficking, and Gene Expression of Messenger RNA-Loaded Lipid Nanoparticles in Dendritic Cells

Lipid nanoparticle (LNP)-mediated mRNA delivery has emerged as a powerful platform for both immunostimulatory and immunomodulatory applications. However, the influence of local immunometabolic cues on the intracellular fate and translational efficiency of mRNA-LNPs remains poorly understood. In this study, we investigated how interferon-gamma (IFN-{gamma}), a potent inducer of indoleamine 2,3-dioxygenase 1 (IDO1), and tryptophan (Trp) deprivation independently and combinatorially affect mRNA-LNP function in DC2.4 dendritic cells. These two cues are canonical drivers of immunoregulatory microenvironments, particularly those that favor tolerogenic dendritic cell programming and the induction of regulatory T cells. Using dual-reporter mRNA constructs and high-resolution confocal imaging, we show that IFN-{gamma} stimulation reduces total cellular mRNA uptake and lysosomal accumulation without affecting translation efficiency and endosomal escape efficiency. Whereas Trp deprivation also reduces the overall cellular uptake of mRNA-LNPs, it also significantly impairs protein synthesis from mRNA-LNPs and modestly reduces endosomal escape, despite having minimal impact on lysosomal mRNA levels. Spatial compartmentalization analysis revealed that IFN-{gamma} and Trp limitation disrupt distinct steps in the delivery-translation cascade, acting independently but additively to suppress the ultimate protein translation from mRNA-LNPs in DC2.4 dendritic cells. These findings highlight the importance of considering local metabolic and cytokine contexts when deploying mRNA-LNPs for immunological applications. Our work provides mechanistic insights into how immunoregulatory environments impair the delivery and translation of mRNA-LNPs, suggesting strategies to tune delivery outcomes for tolerogenic purposes.

biochemistry↗

bioRxiv2025

Type-I nNOS neurons orchestrate cortical neural activity and vasomotion

It is unknown how the brain orchestrates coordination of global neural and vascular dynamics. We sought to uncover the role of a sparse but unusual population of genetically distinct interneurons known as type-I nNOS neurons, using a novel pharmacological strategic to unilaterally ablate these neurons from the somatosensory cortex of mice. Region-specific ablation produced changes in both neural activity and vascular dynamics, decreased power in the delta-band of the local field potential, reduced sustained vascular responses to prolonged sensory stimulation, and abolished the post-stimulus undershoot in cerebral blood volume. Coherence between the left and right somatosensory cortex gamma-band power envelope and blood volume at ultra-low frequencies was decreased, suggesting type-1 nNOS neurons integrate long-range coordination of brain signals. Lastly, we observed decreases in the amplitude of resting-state blood volume oscillations and decreased vasomotion following the ablation of type-I nNOS neurons. This demonstrates that a small population of nNOS-positive neurons are indispensable for regulating both neural and vascular dynamics in the whole brain, raising the possibility that loss of these neurons could contribute to the development of neurodegenerative diseases and sleep disturbances.

neuroscience↗

bioRxiv2020

Forced Abstinence from Alcohol Induces Sex-Specific Depression-like Behavioral and Neural Adaptations in Somatostatin Neurons in Cortical and Amygdalar Regions

Forced abstinence (FA) from alcohol has been shown to produce a variety of anxiety- and depression- like symptoms in animal models. Somatostatin (SST) neurons, a subtype of GABAergic neurons found throughout the brain, are a novel neural target with potential treatment implications in affective disorders, yet their role in alcohol use disorders (AUD) remains to be explored. Here, we examined the neuroadaptations of SST neurons during forced abstinence from voluntary alcohol consumption. Following six weeks of two-bottle choice alcohol consumption and protracted forced abstinence, male and female C57BL/6J mice exhibited a heightened, but sex-specific, depressive-like behavioral profile in the sucrose preference test (SPT) and forced swim test (FST), without changes in anxiety-like behaviors in the elevated plus maze (EPM) and open field test (OFT). FST-induced cFos expressions in the prefrontal cortex (PFC) and ventral bed nucleus of the stria terminalis (vBNST) were altered in FA-exposed female mice only, suggesting a sex-specific effect of forced abstinence on the neural response to acute stress. SST immunoreactivity in these regions was unaffected by forced abstinence, while differences were seen in SST/cFos co-expression in the vBNST. No differences in cFos or SST immunoreactivity were seen in the lateral central nucleus of the amygdala (CEA) and the basolateral amygdala (BLA). Additionally, SST neurons displayed opposing alterations in the PFC and vBNST, with heightened intrinsic excitability in the PFC and diminished intrinsic excitability in the vBNST. These findings provide an overall framework of forced abstinence-induced neuroadaptations in these key brain regions involved in emotional regulation and processing.

neuroscience↗