Biology subjects

Millen, K. J.

Publications and source records attributed to Millen, K. J..

7 recordsLinked to original sources

bioRxiv2025

Elucidating Neurodevelopmental Trajectories in Cancer with Topic Modeling: Revealing Persistent External Granule Layer Lineages in Medulloblastoma

Single-cell transcriptomics transformed our understanding of cellular heterogeneity, yet cross-dataset comparison remains fundamentally limited by batch effects, technology differences, and inconsistent annotation frameworks. These challenges have impeded efforts to connect developmental programs with disease states which creates a critical gap for understanding pediatric cancers with suspected developmental origins. Here, we demonstrate that topic modeling, an unsupervised natural language processing technique, overcomes these barriers by learning transferable transcriptional genetic signatures that generalize across datasets, technologies, and biological contexts without requiring data integration. Applying this framework to over one million fetal cerebellar nuclei, we identify seven distinct topics that capture the developmental spectrum of rhombic lip progenitors through external granule layer (EGL) differentiation, including transitional states missed by conventional clustering. These topics transfer successfully across sequencing technologies (SPLiT-seq to sci-RNA-seq3), developmental timepoints, species (human to mouse), and from single-cell to bulk RNA sequencing of 876 medulloblastoma tumors. We reveal that Sonic hedgehog (SHH) medulloblastoma subtypes retain these topics, corresponding to distinct stages of EGL development. Our findings highlight that developmental timing at tumor initiation fundamentally shapes tumor biology, with immediate implications for subtype-specific therapeutic strategies in pediatric brain cancer. Our workflow establishes topic modeling as a scalable solution for mining expanding genomic atlases with broad applications across different datasets, technologies, and biological contexts.

bioinformatics↗

bioRxiv2024

The IFIH1-A946T risk variant promotes diabetes in a sex-dependent manner

Type 1 diabetes (T1D) is an autoimmune disease in which pancreatic islet {beta}-cells are attacked by the immune system, resulting in insulin deficiency and hyperglycemia. One of the top non-synonymous single-nucleotide polymorphisms (SNP) associated with T1D is in the interferon-induced helicase C domain-containing protein 1 (IFIH1), which encodes an anti-viral cytosolic RNA sensor. This SNP results in an alanine to threonine substitution at amino acid 946 (IFIH1A946T) and confers an increased risk for several autoimmune diseases, including T1D. We hypothesized that the IFIH1A946T risk variant, (IFIH1R) would promote T1D pathogenesis by stimulating type I interferon (IFN I) signaling leading to immune cell alterations. To test this, we developed Ifih1R knock-in mice on the non-obese diabetic (NOD) mouse background, a spontaneous T1D model. Our results revealed a modest increase in diabetes incidence and insulitis in Ifih1R compared to non-risk Ifih1 (Ifih1NR) mice and a significant acceleration of diabetes onset in Ifih1R females. Ifih1R mice exhibited a significantly enhanced interferon stimulated gene (ISG) signature compared to Ifih1NR, indicative of increased IFN I signaling. Ifih1R mice exhibited an increased frequency of plasma cells as well as tissue-dependent changes in the frequency and activation of CD8+ T cells. Our results indicate that IFIH1R may contribute to T1D pathogenesis by altering the frequency and activation of immune cells. These findings advance our knowledge on the connection between the rs1990760 variant and T1D. Further, these data are the first to demonstrate effects of Ifih1R in NOD mice, which will be important to consider for the development of therapeutics for T1D.

immunology↗

bioRxiv2023

Chromosome-scale genome assembly of the African spiny mouse (Acomys cahirinus)

There is increasing interest in the African spiny mouse (Acomys cahirinus) as a model organism because of its ability for regeneration of tissue after injury in skin, muscle, and internal organs such as the kidneys. A high-quality reference genome is needed to better understand these regenerative properties at the molecular level. Here, we present an improved reference genome for A. cahirinus generated from long Nanopore sequencing reads. We confirm the quality of our annotations using RNA sequencing data from four different tissues. Our genome is of higher contiguity and quality than previously reported genomes from this species and will facilitate ongoing efforts to better understand the regenerative properties of this organism.

genomics↗

bioRxiv2023

Neonatal Subarachnoid Hemorrhage Disrupts Multiple Aspects of Cerebellar Development

Over the past decade, survival rates for extremely low gestational age neonates (ELGANs; <28 weeks gestation) has markedly improved. Unfortunately, a significant proportion of ELGANs will suffer from neurodevelopmental dysfunction. Cerebellar hemorrhagic injury (CHI) has been increasingly recognized in the ELGANs population and may contribute to neurologic dysfunction; however, the underlying mechanisms are poorly understood. To address this gap in knowledge, we developed a novel model of early isolated posterior fossa subarachnoid hemorrhage (SAH) in neonatal mice and investigated both acute and long-term effects. Following SAH on postnatal day 6 (P6), we found significant decreased levels of proliferation with the external granular layer (EGL), thinning of the EGL, decreased Purkinje cell (PC) density, and increased Bergmann glial (BG) fiber crossings at P8. At P42, CHI resulted in decreased PC density, decreased molecular layer interneuron (MLI) density, and increased BG fiber crossings. Results from both Rotarod and inverted screen assays did not demonstrate significant effects on motor strength or learning at P35-38. Treatment with the anti-inflammatory drug Ketoprofen did not significantly alter our findings after CHI, suggesting that treatment of neuro-inflammation does not provide significant neuroprotection post CHI. Further studies are required to fully elucidate the mechanisms through which CHI disrupts cerebellar developmental programming in order to develop therapeutic strategies for neuroprotection in ELGANs.

developmental biology↗

bioRxiv2021

Suppression of PIK3CA-driven epileptiform activity by acute pathway control

Patients harboring mutations in the PI3K-AKT-MTOR signaling pathway often develop a spectrum of neurodevelopmental disorders including epilepsy. A significant proportion of them remain unresponsive to conventional anti-seizure medications. Understanding mutation-specific pathophysiology is thus critical for molecularly targeted therapies. We previously determined that mouse models expressing patient-related activating mutation in PIK3CA are epileptic and acutely treatable with PI3K inhibition, irrespective of dysmorphology (Roy et al. 2015). Using the same mutant model, we have now identified physiological mechanisms underlying the dysregulated neuronal excitability and its acute attenuation. We show that Pik3ca-driven hyperexcitability in hippocampal pyramidal neurons is mediated by changes in multiple non-synaptic, cell-intrinsic properties. These are distinct from mechanisms driving epilepsy in TSC/RHEB models. Further, we report that acute inhibition of PI3K or AKT, but not MTOR, suppresses the intrinsic epileptiform nature of the mutant neurons. These data represent an important step towards precision therapeutics against intractable epilepsy, using pathway drugs originally developed as anti-cancer agents.

neuroscience↗

bioRxiv2020

Spatial and single-cell transcriptional landscape of human cerebellar development

ABSTRACTCerebellar development and function require precise regulation of molecular and cellular programs to coordinate motor functions and integrate network signals required for cognition and emotional regulation. However, molecular understanding of human cerebellar development is limited. Here, we combined spatially resolved and single-cell transcriptomics to systematically map the molecular, cellular, and spatial composition of early and mid-gestational human cerebellum. This enabled us to transcriptionally profile major cell types and examine the dynamics of gene expression within cell types and lineages across development. The resulting ‘Developmental Cell Atlas of the Human Cerebellum’ demonstrates that the molecular organization of the cerebellar anlage reflects cytoarchitecturally distinct regions and developmentally transient cell types that are insufficiently captured in bulk transcriptional profiles. By mapping disease genes onto cell types, we implicate the dysregulation of specific cerebellar cell types, especially Purkinje cells, in pediatric and adult neurological disorders. These data provide a critical resource for understanding human cerebellar development with implications for the cellular basis of cerebellar diseases.Competing Interest StatementA.B.R, C.R., and G.Se. are shareholders of Split Bioscience.View Full Text

developmental biology↗

bioRxiv2018

Scarless repair of acute and chronic kidney injury in African Spiny mice (Acomys cahirinus)

Solid organ fibrosis is a major burden on global health and medical care costs. Muroid rodents of the genus Acomys (African Spiny mice) are terrestrial mammals that evolved remarkable abilities to regenerate severe skin wounds without scar formation. However, whether scar-free wound repair in Acomys extends beyond skin to vital internal organs is not known. Here, we used two aggressive kidney injury models known to produce severe renal fibrosis and show that despite equivalent acute kidney injury, there was rapid restoration of nephron structure and function without fibrosis in Acomys compared to extensive fibrosis leading to renal failure in Mus musculus. These results suggest Acomys species have evolved genomic adaptations for wound healing that activate regenerative repair pathways not only in skin, but also in vital internal organs. Our findings have important implications for discovering a long-sought evolutionary solution to internal organ injury and regeneration.

pathology↗