Biology subjects

Hollingsworth, T.

Publications and source records attributed to Hollingsworth, T..

6 recordsLinked to original sources

bioRxiv2026

BXD51: A Robust and Translational Mouse Model for Studying the Pathophysiology of Glaucoma

The aim of this study was to characterize the BXD51 mouse strain as a reproducible model of chronic progressive glaucoma. Unlike the highly susceptible DBA/2J (D2) mutant strain, BXD51 is a genetically stable recombinant inbred line derived from C57BL/6J (B6) and D2 parental lines. Longitudinal assessments of intraocular pressure (IOP), visual acuity (VA), contrast sensitivity (CS), and pattern electroretinogram (pERG) demonstrated that BXD51 mice undergo a delayed decline in visual and retinal ganglion cell (RGC) function. Their decline is biphasic, with a period of initial ocular stress followed by a late-onset, accelerated structural and functional deterioration of RGCs. Anterior segment structural analysis by optical coherence tomography (OCT) and histology demonstrated increasing pigment dispersion and subsequent iridocorneal angle closure. Immunofluorescence analysis of structural neuronal markers (TUBB3 and MAP1A/2) exhibited thinning of the ganglion cell layer (GCL) and inner plexiform layer (IPL) together with axonal degeneration, mirroring the laminar degeneration seen in human glaucoma patients. BXD51 also revealed marked spatial heterogeneity between peripheral and central retina. Multivariate analysis confirmed that BXD51 follows a distinct clinical trajectory that separates it from both wild-type (B6) and a severe glaucoma model (D2). By spanning the range between resistance and extreme susceptibility to glaucomatous neurodegeneration, this study establishes the BXD51 mouse as a translational platform for mechanistic studies and for evaluating long-term neuroprotective strategies.

neuroscience↗

bioRxiv2026

Perinatal Semaglutide Treatment Improves Maternal Health and Mitigates Offspring Metabolic Dysfunction in a Mouse Model of Maternal Obesity

Early-life exposures during critical periods of development significantly impact lifelong metabolic risk and likely contribute to the rising rates of obesity, type 2 diabetes, and metabolic dysfunction-associated steatotic liver disease (MASLD) in children. Here, we evaluated the safety and metabolic effects of semaglutide, a GLP-1 receptor agonist (GLP-1 RA), administered from preconception through lactation in dams fed a high-fat diet (HFD) or standard diet, and assessed metabolic outcomes in dams and their offspring. Offspring were weaned to a standard diet. We found that semaglutide improved body composition and glucose metabolism in HFD-fed dams during pregnancy. These maternal changes persisted 10 weeks after weaning despite discontinuation of semaglutide treatment. HFD exposure impaired glucose homeostasis and promoted hepatic steatosis in offspring at 18 weeks. These effects were ameliorated by maternal semaglutide treatment. Importantly, metabolic improvements in dams and offspring occurred without adverse effects on conception rate or fetal viability. These findings suggest that GLP-1 RA during the perinatal period can improve maternal and offspring metabolic health in a mouse model of obesity and support further investigation of GLP-1-based therapies to mitigate maternal metabolic dysfunction and improve metabolic risk in children. ARTICLE HIGHLIGHTS* Rates of obesity, type 2 diabetes, and fatty liver disease are rising in children, in part due to maternal obesity and insulin resistance that program offspring metabolic risk during the perinatal period. * We asked whether the GLP-1 receptor agonist (GLP-1 RA), semaglutide, administered during critical developmental windows could prevent adverse outcomes in offspring using a diet-induced mouse model of maternal obesity. * Semaglutide, given to dams from preconception through lactation, improved maternal metabolism and ameliorated metabolic dysfunction in offspring caused by maternal high-fat diet. * These findings highlight a potential role for perinatal GLP-1 receptor agonism to improve maternal metabolic health and reduce metabolic risk in offspring.

physiology↗

bioRxiv2026

Multi-omic profiling of early pregnancy small and large plasma extracellular vesicles reveals placental, metabolic, and structural adaptation signatures

Early human pregnancy is a critical period characterized by rapid growth and extensive maternal-fetal communication that influence maternal and fetal outcomes. Circulating extracellular vesicles (EVs) have the capacity to capture cargo that reflect these processes in real-time; however, signatures of EV subtypes during early pregnancy are poorly defined. Here we quantified mitochondrial DNA (mtDNA) and performed transcriptomic and proteomic profiling of small ([~]100 nm) and large ([~]200 nm) plasma EVs from n=10 normal pregnancies (11-15 weeks) to define subtype-specific molecular signatures. mtDNA and mitochondrial protein content were more abundant in large EVs (lEVs). lEVs also contained a more complex set of long RNAs enriched for placental, immune, and mitochondrial-related transcripts compared with small EVs (sEVs). Proteomic profiling showed enrichment of canonical EV markers and extracellular matrix proteins in sEVs, whereas lEVs were preferentially associated with pregnancy-specific proteins, including proteins related to placental hormone production. MicroRNAs (miRNAs) accounted for [~]25% of small RNAs in both EV subtypes with miR-223 and miR-16 enriched in lEVs and miR-639 enriched in sEVs. These data together, support a model where small and large plasma EVs have distinct, yet complementary signatures reporting systemic adaptations during the critical 11-15 week transition period. This work establishes a foundational framework for future studies linking EV signatures to placental dysfunction and adverse outcomes.

physiology↗

bioRxiv2026

MONICA: A Web Application for Automated Whole Optic Nerve Contour Extraction and Morphometric Analysis Validated Across Taxonomic Orders and Image Quality Levels

Quantitative assessment of optic nerve health requires metrics beyond axon counts alone. Axon density and glial coverage fraction correlate with clinical measures of visual function, yet no existing automated tool extracts optic nerve cross-sectional boundaries to enable their calculation. We developed MONICA (Morphometrics from Optic Nerve Imaging Contour Analysis), a web application that integrates AxonDeepSeg deep learning segmentation with a novel morphology-based contour extraction algorithm to automatically derive whole nerve boundaries alongside axon and myelin masks. The contour extraction algorithm was validated against manual ground truth annotations using 15 optic nerve cross-sections spanning two taxonomic orders (mouse, rabbit), two mouse strains (BXD29, BXD51), and varying preparation quality levels (modern and archival samples). Automated contour extraction demonstrated excellent agreement with manual annotations, achieving an overall Dice similarity coefficient (a measure of segmentation overlap) of 0.987 {+/-} 0.009. Balanced precision (0.985) and recall (0.989) values indicated that the algorithm neither systematically over-segments nor under-segments nerve boundaries. MONICA requires no local software installation and runs entirely in-browser, providing batch processing for high-throughput phenotyping alongside a full suite of per-axon morphometrics. MONICA provides researchers with an accessible tool for complete nerve cross-section morphometry.

neuroscience↗

bioRxiv2024

Brown adipose tissue thermogenesis rhythms are driven by the SCN independent of adipocyte clocks

Circadian misalignment has been associated with obesity both in rodents and humans. Brown adipose tissue (BAT) thermogenesis contributes to energy expenditure and can be activated in adults to reduce body weight. Although previous studies suggest control of BAT thermogenesis by the circadian clock, the site and mechanisms of regulation remain unclear. We used mice with genetic disruption of the circadian clock in the suprachiasmatic nucleus (SCN) and peripheral tissues to delineate their role in BAT thermogenesis. Global post-natal deletion of Bmal1 in adult mice (Bmal1-/-) abolishes the rhythms of interscapular BAT temperature, a measure of thermogenesis, while normal locomotor activity rhythms are maintained under a regular 12h light-12h dark schedule. Activation of thermogenesis either by exposure to cold or adrenergic stimulation of BAT displays a diurnal rhythm with higher activation during the active period. Both the rhythm and the magnitude of the thermogenic response is preserved in Bmal1-/- mice. In contrast to mice with global deletion of Bmal1, mice with brown adipocyte (Ucp1-Bmal1-/-) or brown and white adipocyte (Ad-Bmal1-/-) deletion of Bmal1 show intact rhythms of BAT thermogenic activity. The capacity of Ucp1-Bmal1-/- mice to activate thermogenesis in response to exposure to cold is identical to WT mice, independent of time of stimulation. Circadian rhythmicity of interscapular BAT temperature is lost in mice with SCN deletion of Bmal1 (SCN-Bmal1-/-), indicating control of BAT thermogenesis rhythms by the SCN. Control mice exhibit rhythmic BAT glucose and fatty acid uptake - a rhythm that is not recapitulated in Bmal1-/- and SCN-Bmal1-/- mice but is present in Ucp1-Bmal1-/- and Ad-Bmal1-/- mice. BAT cAMP and phosphorylated hormone-sensitive lipase (pHSL) is reduced during the active period in Bmal1-/- and SCN-Bmal1-/- mice consistent with reduced sympathetic tone. Furthermore, sympathetic denervation of BAT ablates BAT temperature rhythms in WT mice. Taken together, our findings suggest that the SCN drives rhythms of BAT thermogenesis through adipocyte clock-independent, sympathetic signaling to the BAT.

physiology↗

bioRxiv2022

Genome-Wide Association Study Finds Multiple Loci Associated with Intraocular Pressure in HS Rats

Elevated intraocular pressure (IOP) is influenced by environmental and genetic factors. Increased IOP is a major risk factor for most types of glaucoma, including primary open angle glaucoma (POAG). Investigating the genetic basis of IOP may lead to a better understanding of the molecular mechanisms of POAG. The goal of this study was to identify genetic loci involved in regulating IOP using outbred heterogeneous stock (HS) rats. HS rats are a multigenerational outbred population derived from eight inbred strains that have been fully sequenced. This population is ideal for genome-wide association studies (GWASs) owing to the accumulated recombinations among well-defined haplotypes, the relatively high allele frequencies, the accessibility to a large collection of tissue samples, and the large allelic effect size compared to human studies. Both male and female HS rats (N=1,812) were used in the study. Genotyping-by-sequencing was used to obtain ~3.5 million single nucleotide polymorphisms (SNP) from each individual. SNP heritability for IOP in HS rats was 0.32, which agrees with other studies. We performed a GWAS for the IOP phenotype using a linear mixed model and used permutation to determine a genome-wide significance threshold. We identified three genome-wide significant loci for IOP on chromosomes 1, 5, and 16. Next, we sequenced the mRNA of 51 whole eye samples to find cis-eQTLs to aid in identification of candidate genes. We report 5 candidate genes within those loci: Tyr, Ctsc, Plekhf2, Ndufaf6 and Angpt2. Tyr, Ndufaf6 and Angpt2 genes have been previously implicated by human GWAS of IOP-related conditions. Ctsc and Plekhf2 genes represent novel findings that may provide new insight into the molecular basis of IOP. This study highlights the efficacy of HS rats for investigating the genetics of elevated IOP and identifying potential candidate genes for future functional testing. Contribution to the field statementGlaucoma is the leading cause of irreversible blindness worldwide. Intraocular pressure (IOP) is the only known modifiable risk factor. This study describes results of the genome-wide association study (GWAS) performed in outbred rats that identifies known and novel genes involved in IOP regulation. To our knowledge, this is the first GWAS performed for IOP in a rat model. Identifying novel candidate genes in the rat model provides insight into the risk factors for glaucoma in humans and potential pharmacological targets for regulating IOP. The rat model is advantageous for studying natural variations in IOP, controlling environmental exposures, and providing easier access to tissue that can be used in phenotyping and gene expression in future studies.

genomics↗