Biology subjects

Lane, A. R.

Publications and source records attributed to Lane, A. R..

5 recordsLinked to original sources

bioRxiv2026

Distinct signaling mechanisms and proteome phenotypes are elicited by compartment-specific genetic defects of copper homeostasis

Impairments to the complex machinery regulating copper homeostasis lead to neurodevelopmental diseases, demonstrating the importance of copper for neuronal health and maintenance. The exact mechanisms by which the brain responds to copper deficiency following disruptions to the copper transporters ATP7A and CTR1 in conditions such as Menkes disease remain unclear, though failure to supply complex IV of the respiratory chain with copper is suspected to account for substantial pathology. Here, we studied mechanisms of copper deficiency using systems biology approaches to contrast isogenic CTR1- and COX17-deficient cells, which model copper deficiency at the level of the whole cell or complex IV, respectively. Multiomics approaches revealed distinct signaling mechanisms elicited by compartment-specific genetic defects of copper homeostasis, spanning multiple organelles and biological functions. Specifically, COX17 KO cells exhibited elevated AMPK activity and blunted mTOR activity relative to CTR1-null cells. Manipulating mTOR activity elicited inverse effects on survival in CTR1-deficient cells and flies as compared to their COX17-deficient counterparts. Increased mTOR activity and downstream protein synthesis is adaptive in models of copper deficiency but deleterious in COX17-deficient cells and flies. We propose that mTOR activation represents a resilience mechanism that fails following sustained copper deficiency and impairments to mitochondrial respiration. SignificanceO_LIComparative proteomics reveals distinct molecular mechanisms downstream of compartmentalized copper deficiency C_LIO_LICOX17- and CTR1-deficient cells exhibit distinct patterns of AMPK/mTOR pathway activity C_LIO_LImTOR and downstream S6K activity is protective in cellular copper deficiency but not in compartmentalized mitochondrial copper deficiency C_LI

cell biology↗

bioRxiv2025

Lead (Pb) exposure alters neural cell fate in the developing human brain

The heavy metal lead (Pb) is a developmental neurotoxicant associated with cognitive and behavioral deficits, but the cellular mechanisms underlying these impairments remain unclear. Here we show that prenatal Pb exposure biases human radial glia fate, prolonging neurogenesis and suppressing astrogenesis. We used hiPSC-derived cortical organoids, primary human fetal tissue, and in vivo xenografts to demonstrate that Pb exposure alters radial glial differentiation. Pb-exposed organoids contain a higher proportion of neurons and fewer astrocytes. We validated this differentiation bias in primary radial glia from human cortices (GW16-20), observing Pb-associated reductions in astrocyte commitment via genetic lineage tracing. This correlated with increased H3K27me3, a repressive histone modification deposited by the histone methyltransferase complex PRC2, suggesting epigenetic reprogramming as a mechanistic link between Pb and neural cell fate commitment. Our findings indicate that prenatal Pb exposure impacts lineage commitment in the developing brain, which may contribute to cognitive and behavioral impairment.

neuroscience↗

bioRxiv2024

Adaptive protein synthesis in genetic models of copper deficiency and childhood neurodegeneration

Rare inherited diseases caused by mutations in the copper transporters SLC31A1 (CTR1) or ATP7A induce copper deficiency in the brain, causing seizures and neurodegeneration in infancy through poorly understood mechanisms. Here, we used multiple model systems to characterize the molecular mechanisms by which neuronal cells respond to copper deficiency. Targeted deletion of CTR1 in neuroblastoma cells produced copper deficiency that was associated with a metabolic shift favoring glycolysis over oxidative phosphorylation. Proteomic and transcriptomic analysis of CTR1 KO cells revealed simultaneous upregulation of mTORC1 and S6K signaling and reduced PERK signaling. Patterns of gene and protein expression and pharmacogenomics show increased activation of the mTORC1-S6K pathway as a pro-survival mechanism, ultimately resulting in increased protein synthesis. Spatial transcriptomic profiling of Atp7aflx/Y :: Vil1Cre/+ mice identified upregulated protein synthesis machinery and mTORC1-S6K pathway genes in copper-deficient Purkinje neurons in the cerebellum. Genetic epistasis experiments in Drosophila demonstrated that copper deficiency dendritic phenotypes in class IV neurons are partially rescued by increased S6k expression or 4E-BP1 (Thor) RNAi, while epidermis phenotypes are exacerbated by Akt, S6k, or raptor RNAi. Overall, we demonstrate that increased mTORC1-S6K pathway activation and protein synthesis is an adaptive mechanism by which neuronal cells respond to copper deficiency. SignificanceO_LICopper deficiency is present in rare conditions such as Menkes disease and CTR1 deficiency and in more common diseases like Alzheimers. The mechanisms of resilience and ultimate susceptibility to copper deficiency and associated pathology in the brain remain unknown. C_LIO_LIWe demonstrate that in a human cell line, Drosophila, and the mouse cerebellum, copper-deficient neuronal cells exhibit increased protein synthesis through mTORC1 activation and decreased PERK (EIF2AK3) activity. C_LIO_LIUpregulation of protein synthesis facilitates resilience of neuronal cells to copper deficiency, including partial restoration of dendritic arborization. Our findings offer a new framework for understanding copper deficiency-related pathology in neurological disorders. C_LI

neuroscience↗

bioRxiv2023

SPINAL V1 INHIBITORY INTERNEURON CLADES DIFFER IN BIRTHDATE, PROJECTIONS TO MOTONEURONS AND HETEROGENEITY

Spinal cord interneurons play critical roles shaping motor output, but their precise identity and connectivity remain unclear. Focusing on the V1 interneuron cardinal class we defined four major V1 subsets according to neurogenesis timing, genetic lineage-tracing, synaptic output to motoneurons, and synaptic inputs from muscle afferents. Birthdate delineates two early born (Renshaw and Pou6f2) and two late born (Foxp2 and Sp8) V1 clades, showing that sequential neurogenesis produces different V1 subsets. Early born Renshaw cells and late born Foxp2-V1 interneurons are tightly coupled to motoneurons, while early born Pou6f2-V1 and late born Sp8-V1 interneurons are not, indicating that timing of neurogenesis does not correlate with motoneuron targeting. V1 clades also differ in cell numbers and diversity. Lineage labeling shows that the Foxp2-V1 clade contains over half of all V1 interneurons, provides the largest inhibitory input to motoneuron cell bodies and includes subgroups that differ in birthdate, location, and proprioceptive input. Notably, one Foxp2-V1 subgroup, defined by postnatal Otp expression is positioned near the lateral motor column and receives substantial input from proprioceptors, consistent with an involvement in reciprocal inhibitory pathways. Combined tracing of ankle flexor sensory afferents and interneurons monosynaptically connected to ankle extensors confirmed placement of Foxp2-V1 interneurons in reciprocal inhibitory pathways. Our results validate previously proposed V1 clades as unique functional subtypes that differ in circuit placement, with Foxp2-V1 cells forming the most heterogeneous subgroup. We discuss how V1 organizational diversity enables understanding of their roles in motor control, with implications for their diverse ontogenetic and phylogenetic origins. SIGNIFICANCE STATEMENTThe complexity of spinal interneuron diversity and circuit organization represents a challenge to understand neural control of movement in normal adults as well as during motor development and in disease. Inhibitory interneurons are a core element of these spinal circuits. V1 interneurons comprise the largest group of inhibitory interneurons in the ventral horn, and their organization remains unclear. Here we present a comprehensive examination of V1 subtypes according to neurogenesis, placement in spinal motor circuits, and motoneuron synaptic targeting. V1 diversity increases during evolution from axial-swimming fishes to limb-based mammalian terrestrial locomotion. This increased diversity is reflected in the size and heterogeneity of the Foxp2-V1 clade, a group closely associated with limb motor pools. We show that Foxp2-V1 interneurons establish the densest direct inhibitory input to motoneurons, especially on cell bodies. These findings are particularly significant because recent studies have shown that motor neurodegenerative diseases like amyotrophic lateral sclerosis (ALS) affect inhibitory V1 synapses on motoneuron cell bodies and Foxp2-V1 interneurons themselves in the earliest stages of pathology.

neuroscience↗

bioRxiv2022

APOE Expression and Secretion are Modulated by Copper-Dependent and -Independent Mitochondrial Dysfunction

Mitochondria influence cellular function through both cell-autonomous and non-cell autonomous mechanisms, such as production of paracrine and endocrine factors. Here, we demonstrate that mitochondrial regulation of the secretome is more extensive than previously appreciated, as both genetic and pharmacological disruption of the electron transport chain caused upregulation of the Alzheimers disease risk factor apolipoprotein E (APOE) and other secretome components. This upregulation of secretory proteins was of a similar extent as modifications to the mitochondrial annotated proteome. Indirect disruption of the electron transport chain by gene editing of SLC25A mitochondrial membrane transporters as well as direct genetic and pharmacological disruption of either complexes I, III, or the copper-containing complex IV of the electron transport chain, elicited upregulation of APOE transcript, protein, and secretion, up to 49-fold. These APOE phenotypes were robustly expressed in diverse cell types and iPSC-derived human astrocytes as part of an inflammatory gene expression program. Moreover, age- and genotype-dependent decline in brain levels of respiratory complex I preceded an increase in APOE in the 5xFAD mouse model. We propose that mitochondria act as novel upstream regulators of APOE-dependent cellular processes in health and disease.

cell biology↗