Biology subjects

Brown, E. G.

Publications and source records attributed to Brown, E. G..

5 recordsLinked to original sources

bioRxiv2026

Synergistic Combination of Bioengineered MicroRNA and Chemotherapy Across High-Risk Neuroblastoma Subtypes

Despite intensive treatment, high-risk neuroblastoma (HRNB) remains a leading cause of cancer-related mortality in children. Current treatment paradigms include multimodal systemic treatments and multi-agent chemotherapy, which is limited by substantial acute and long-term toxicities. Platinum-based chemotherapy is a cornerstone of this treatment but is fraught with side effects and stands to benefit from dose reduction strategies. MicroRNA (miR)-based therapeutics represent an attractive strategy to simultaneously moderate multiple oncogenic pathways, providing a potential avenue to enhance the efficacy of current treatment regimens. However, the development of miR therapeutics has largely relied on chemically synthesized ones, which are limited by issues of inconsistency and poor in vivo stability. Biologically produced, tRNA/pre-miR containing bioengineered miRs (bioRNAs) address these limitations. We investigated the therapeutic potential of bioRNA encoding miR-124 and miR-34a across molecularly distinct HRNB models and evaluated their ability to enhance cisplatin efficacy. Both bioRNAs significantly suppressed neuroblastoma cell viability in vitro, with proteomic analyses demonstrating preferential induction of neuronal differentiation by miR-124 and apoptotic signaling by miR-34a. Combining bioRNA with cisplatin produced robust synergy across multiple HRNB lines, enhancing apoptosis while simultaneously promoting differentiation-associated phenotypes. In vivo, both bioRNAs suppressed tumor growth as monotherapies, while combination with low-dose cisplatin produced the strongest responses across multiple xenograft models with different HRNB subtypes. Notably, low-dose cisplatin combined with bioRNA therapy frequently achieved tumor control comparable to, or greater than, that observed with high-dose cisplatin monotherapy while maintaining favorable tolerability. These findings establish bioRNAs as potent cisplatin sensitizers and support bioRNA-based combination therapy as a strategy for improving HRNB treatment while reducing chemotherapy-associated toxicity in children.

bioengineering↗

bioRxiv2025

Elevated brain α-synuclein, phosphorylated-tau, and oxidative stress in mice that survived influenza A pneumonitis

Background: Influenza virus exposure elevates the incidence of parkinsonism. We and others previously discovered that allelic variants at the Parkinson's-linked LRRK2 locus modulate host responses to virulent microbes. Objective: We asked whether Lrrk2 mutations modify disease outcomes in adult animals following a nasally acquired lung infection. Methods: We inoculated C57BL/6J mice of mutant knock-in Lrrk2 genotypes with influenza A virus, H1N1-serotype (1 x LD 50 = 2,000 plaque-forming units). Results: During H1N1-induced pneumonitis neither homozygous nor heterozygous mutations of kinase activity-increasing Lrrk2G2019S or kinase-dead Lrrk2D1994S altered the course of sickness in mice when compared to wild-type littermates, as determined by survival rates, viral titres and weight changes in both sexes. However, six weeks after inoculation brains of H1N1-exposed, homozygous Lrrk2 p.G2019S animals showed higher pSer129 -synuclein and pSer199 tau levels than mock-treated, mutant mice (P<0.01). The ratios of phosphorylated tau-to-total tau and phosphorylated -synuclein-to-total -synuclein also rose in H1N1-exposed Lrrk2 p.G2019S mice (P<0.05). Further, we found that nitrotyrosination of the brain proteome was significantly increased in Lrrk2G2019S survivors vs. mock-exposed littermates (P<0.05). Brain H2O2 concentrations were elevated in male, H1N1-inoculated wild-type animals (with a trend seen in females and Lrrk2G2019S mice), an effect that was abrogated in kinase-dead Lrrk2D1994S mice. Conclusion: Homozygous Lrrk2G2019S-mutant mice that survived infection by a life-threatening, pneumotropic RNA virus show changes in brain levels of oxidative stress, pSer199 tau and pSer129 -synuclein. These results could be of relevance to the initiation of neurodegeneration-linked changes in humans and may help explain differences in the penetrance rate and expressivity of LRRK2 mutants.

neuroscience↗

bioRxiv2024

A Protocol for Neuralized Murine Olfactory Organoids

Chronic olfactory dysfunction can be associated with parkinsonism, dementia, demyelinating disorders and schizophrenia. The olfactory epithelium (OE) represents an interface between the environment and the central nervous system. Mounting evidence implicates environmental factors in neurodegenerative disease processes, necessitating investigations into their interactions with the hosts genome. In Parkinson disease, hyposmia often precedes motor symptoms, raising the possibility that the OE could be involved in disease initiation. We previously demonstrated abundant -synuclein expression in mammalian OE as well as aggregate formation in the olfactory nerve. Current in vitro models of OE are limited, relying primarily on post-mitotic cultures established from biopsies. To address this gap, we present a method for generating olfactory organoids of OE from adult mice. These organoids comprise neuronal and non-neuronal cell types, including sustentacular cells, thus encompassing structural elements of OE in situ. Expression of the olfactory sensory neuron marker OMP and Parkinsons-linked -synuclein was also detected in olfactory organoids, highlighting their potential usefulness to mechanistic research. We established OE organoids that were kept in culture for up to 3 weeks. In addition, we inoculated organoids with the neurotropic vesicular stomatitis virus to model infections. We conclude that this olfactory organoid model system offers a new platform for studying airborne environmental factors in their interactions with a genetically defined host; this, to study OE biology and enable the exploration of disease processes within olfactory tissue.

neuroscience↗

bioRxiv2024

Variants in Lrrk2 and Snca deficiency do not alter the course of primary encephalitis due to neurotropic reovirus T3D in newborn mice

Variants of the leucine-rich repeat kinase-2 (LRRK2) and -synuclein (SNCA) genes are associated with Parkinsons disease risk. We previously demonstrated that two Lrrk2 knock-in variants as well as Snca expression alter survival rates from combined pneumonitis and encephalitis following intranasal inoculation of newborn mice with a double-stranded RNA virus: respiratory-enteric-orphan virus, serotype-3 strain Dearing (reovirus T3D). Here, we examined whether outcomes of direct inoculation of the brain by reovirus T3D, which invariably causes lethal encephalitis within 15 days, would also be modified by variants in Lrrk2 and Snca. When we inoculated newborn mice intracerebrally with 5x102 plaque-forming units of reovirus T3D, we found that, when compared to wild-type littermates, Lrrk2 p.G2019S mutant mice and kinase-dead p.D1994S mutant animals showed the same time-to-death intervals post-infection, revealed no sex difference, and had similar viral titres in the brain. Furthermore, the reduction or absence of endogenous -synuclein also did not alter the course of encephalitis in parallel studies. These outcomes are in contrast to those following the intranasal inoculation paradigm of newborn mice, in which Lrrk2 and wild-type -synuclein were both protective in infection outcomes. Together, these findings suggest that the Parkinsons disease-linked Lrrk2 and Snca genes contribute predominantly to systemic, innate responses by the host following reovirus T3D exposure.

immunology↗

bioRxiv2019

An alternative AUG codon that produces an N-terminally extended form of the influenza A virus NP is a virulence factor for a swine-derived virus.

The 2009 influenza A virus (IAV) pandemic (pdm2009) was caused by a swine H1N1 virus with several atypical genetic features. Here, we investigate the origin and significance of an upstream AUG (uAUG) codon in the 5-untranslated region of the NP gene. Phylogeny indicated that the uAUG codon arose in the classical swine IAV lineage in the mid 20th Century, and has become fixed in the current triple reassortant, variant pdm2009 swine IAV and human pdm2009 lineages. Functionally, it supports leaky ribosomal initiation in vitro and in vivo to produce two isoforms of NP: canonical, and a longer \"eNP\". The uAUG codon had little effect on viral gene expression or replication in vitro. However, in both murine and porcine models of IAV infection, removing the uAUG codon gene attenuated pdm2009 virus pathogenicity. Thus, the NP uAUG codon is a virulence factor for swine IAVs with proven zoonotic ability.

microbiology↗