Biology subjects

Nolan, E.

Publications and source records attributed to Nolan, E..

5 recordsLinked to original sources

bioRxiv2026

Regulation of sociality and neuronal development by the translation initiation factor eIF4H1 in Drosophila

Most animal species exhibit some level of sociality. However, whether sociality-related traits evolved independently, or are instead derived from common core mechanisms, remains controversial. Nevertheless, an emerging theoretical framework stipulates that key aspects of how animals interact with their social environments may be regulated by a phylogenetically conserved genetic toolkit. Therefore, we hypothesized that mutations that lead to social deficits in specific human disorders may implicate genes that play conserved roles in the regulation of core social traits across Animalia. Specifically, here we focus on genes associated with Williams syndrome (WS), a rare human multi-system disorder characterized in part by hypersocial cognitive traits. WS is caused by a hemizygous chromosomal microdeletion of 25-28 protein-coding genes. Consequently, it has been hypothesized that haploinsufficiency in at least one of these genes plays an important role in the development and/or function of social neural circuits in humans. Because the Drosophila genome encodes orthologs of 17 of the 28 genes deleted in WS, we reasoned that at least some of them may serve a conserved role in the regulation of social traits across flies and humans, as predicted by the genetic toolkit framework. Using a neuron-specific RNAi knockdown screen, we identified eIF4H1, an ortholog of a highly conserved subunit of the eukaryotic translation initiation complex eIF4F, as a candidate gene for neuronal regulation of sociality in the fly. We show that eIF4H1 expression is predominantly neuronal in the adult fly brain, and that its action plays a differential role in the organization of specific dopaminergic neuron subtypes that are associated with sociality and cognitive functions. These results indicate that eIF4H1 may serve a conserved function in regulating the development of the neuronal circuits that regulate social behaviors, thus supporting the idea of a conserved sociality genetic toolkit.

genetics↗

bioRxiv2025

Inhibition of neutrophil degranulation by Nexinhib20 delays the development of radiation-induced pulmonary fibrosis

Despite advances in radiation delivery techniques that enhance tumour targeting and minimise collateral exposure, healthy tissues remain susceptible to radiation-induced fibrosis, a chronic and progressive condition that can severely compromise patient quality of life. Therapeutic options to prevent or treat radiation-induced fibrosis remain limited. Recent work has shown that neutrophils infiltrating healthy lung tissue after irradiation adopt an activated phenotype capable of perturbing cellular responses of both epithelial and mesenchymal cells. However, the contribution of these radiation-educated neutrophils to the development of radiation-induced fibrosis remains unclear. Using targeted, image-guided lung irradiation to deliver a dose sufficient to induce fibrosis within four months, we demonstrate that neutrophils are essential for the efficient development of clinically evident fibrosis. Lung irradiation educates neutrophils, enabling them to promote early alterations in the extracellular matrix shortly after radiation exposure. We further show that this "educated" phenotype depends on neutrophil degranulation activity. Pharmacological inhibition of degranulation with Nexinhib20 redirected these cells toward a pro-angiogenic and anti-fibrotic phenotype. Importantly, this treatment was also associated with a transcriptional shift in mesenchymal cells away from a pro-fibrotic program, resulting in a marked delay in the onset of radiation-induced fibrosis. Importantly, Nexinhib20 did not impair the efficacy of cancer radiotherapy, underscoring its potential as a therapeutic strategy to prevent fibrotic complications without diminishing anti-tumour effectiveness.

cancer biology↗

bioRxiv2025

Mutations in ASH1L cause a neurodevelopmental disorder with sex differences in epilepsy and autism

To understand brain phenotypes associated with ASH1L, we performed both studies in mouse models and clinical phenotyping of human subjects. We found in mice that ASH1L mutations result in seizures, microcephaly, and also less complex dendritic morphology. When we analyzed human subjects based for epilepsy, intellectual disability, and ASD, we found sex differences in epilepsy and autism, with epilepsy predominantly in female and ASD in male subjects. To understand the cellular and molecular mechanisms of the sex-difference, we performed whole cell patch clamp electrophysiology in mice and found hyperexcitability in female compared with male hippocampal CA1 neurons. We report the identification of sex-specific transcriptomic signatures resulting from ASH1L haploinsufficiency. Differentially expressed genes in female mice showed distinct association with epileptic encephalopathy, postnatal microcephaly and autistic behaviors. Thus, the role of ASH1L in specific circuits may be sex-dependent leading to sexual dimorphic effects from disruption of this gene.

neuroscience↗

bioRxiv2022

A palmitate-rich metastatic niche enables metastasis growth via p65 acetylation

Cancer cells outgrowing in distant organs of metastasis rewire their metabolism to fuel on the available nutrients. While this is often considered an adaptive pressure limiting metastasis formation, some nutrients available at the metastatic site naturally or through changes in organ physiology may inherently promote metastatic growth. We find that the lung, a frequent site of metastasis, is a lipid-rich environment. Moreover, we observe that pathological conditions such as pre-metastatic niche formation and obesity further increase the availability of the fatty acid palmitate in the lung. We find that targeting palmitate processing inhibits spheroid growth in vitro and metastasis formation in lean and obese mice. Mechanistically, we discover that breast cancer cells use palmitate to synthesize acetyl-CoA in a carnitine palmitoyltransferase 1a (CPT1a)-dependent manner. Lysine acetyltransferase 2a (KAT2a), whose expression is promoted by palmitate availability, relies on the available acetyl-CoA to acetylate the NF-{kappa}B subunit p65. This favors nuclear location of p65 and activates a pro-metastatic transcriptional program. Accordingly, deletion of KAT2a phenocopies CPT1a silencing in vitro as well as in vivo and patients with breast cancer show co-expression of both proteins in metastases across palmitate-rich metastatic sites. In conclusion, we find that palmitate-rich environments foster metastasis growth by increasing p65 acetylation resulting in elevated NF-{kappa}B signaling.

cancer biology↗

bioRxiv2021

The human innate immune protein calprotectin elicits a multi-metal starvation response in Pseudomonas aeruginosa

To combat infections, the mammalian host limits availability of essential transition metals such as iron (Fe), zinc (Zn), and manganese (Mn) in a strategy termed "nutritional immunity". The innate immune protein calprotectin (CP) contributes to nutritional immunity by sequestering these metals to exert antimicrobial activity against a broad range of microbial pathogens. One such pathogen is Pseudomonas aeruginosa, which causes opportunistic infections in vulnerable populations including individuals with cystic fibrosis. CP was previously shown to withhold Fe(II) and Zn(II) from P. aeruginosa and induce Fe- and Zn-starvation responses in this pathogen. In this work, we performed quantitative, label-free proteomics to further elucidate how CP impacts metal homeostasis pathways in P. aeruginosa. We report that CP induces an incomplete Fe-starvation response, as many Fe-containing proteins that are repressed by Fe limitation are not affected by CP treatment. The Zn-starvation response elicited by CP seems to be more complete than the Fe-starvation response and includes increases in Zn transporters and Zn-independent proteins. CP also induces the expression of membrane-modifying proteins, and metal-depletion studies indicate this response results from the sequestration of multiple metals. Moreover, the increased expression of membrane-modifying enzymes upon CP treatment correlates with increased resistance to polymyxin B. Thus, response of P. aeruginosa to CP treatment includes both single and multi-metal starvation responses and includes many factors related to virulence potential, broadening our understanding of this pathogens interaction with the host. ImportanceTransition metals are critical for growth and infection by all pathogens, and the innate immune system withholds these metals from pathogens to limit their growth in a strategy termed "nutritional immunity". While multi-metal depletion by the host is appreciated, the majority of metal depletion studies have focused on individual metald. Here we use the innate immune protein calprotectin (CP), which complexes with several metals including iron (Fe), zinc (Zn), and manganese (Mn), and the opportunistic pathogen Pseudomonas aeruginosa to investigate multi-metal starvation. Using an unbiased label-free proteomics response, we demonstrate that multi-metal withholding by CP induces a regulatory response that is not merely additive of individual metal starvation responses, including the induction of Lipid A modification enzymes.

microbiology↗