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Biology subjects

Anderson, T. R.

Publications and source records attributed to Anderson, T. R..

4 recordsLinked to original sources

A human-specific genetic modifier reconfigures large-scale cortical network dynamics underlying behavioral performance

Cortical expansion in the human lineage was accompanied by alterations in cortical circuit architecture, including an elaboration of cortico-cortical connectivity. Yet how these changes reshape network computation to support behavior remains poorly understood. Here we leverage a mouse model expressing SRGAP2C, a human-specific gene duplication that modifies cortical circuit development and increases cortico-cortical connectivity, to ask how this remodeled architecture shapes network dynamics during learning. As mice acquire expertise on a sensory discrimination task, SRGAP2C drives broader interhemispheric correlation, distributed task-relevant encoding, and enhanced directed influence from frontal and associative regions. Texture representations in primary sensory cortex become more separable during motor preparation, supporting improved discrimination under demanding conditions. These findings demonstrate that human-specific changes in cortical circuit architecture do not simply scale up but rather reconfigure the cortical dynamics that organize sensory-to-motor transformation in a manner that tracks behavioral performance under demanding conditions, linking genomic innovations in the Homo lineage to large-scale cortical network function.

neuroscience↗

PI5P4Kα Regulates Iron Balance to Promote Metabolic Fitness in Pancreatic Cancer

Phosphoinositide kinases generate distinct phosphoinositides that regulate processes that maintain cellular fitness. Phosphatidylinositol 5-phosphate 4-kinases (PI5P4Ks) have garnered interest for their role in cancer metabolism and cellular trafficking; however, their function in pancreatic ductal adenocarcinoma (PDAC) remains unexplored. Given the unique metabolic demands of PDAC cells, which heavily rely on altered trafficking pathways to support their growth, investigating PI5P4Ks in this context may reveal critical insights. We identify PI5P4K as a regulator of PDAC cell fitness through its key role in maintaining iron homeostasis. PI5P4K depletion causes metabolic disruptions and reduced intracellular iron import, leading to the induction of apoptosis in PDAC cells that is reversed by iron supplementation. Notably, we find that PI5P4K knockdown suppresses tumor growth in a xenograft mouse model of PDAC. These results not only illuminate the mechanistic underpinnings of PI5P4K function in PDAC but also position it as a promising therapeutic target for this disease. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=165 SRC="FIGDIR/small/647654v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@17f52e5org.highwire.dtl.DTLVardef@1b78c1org.highwire.dtl.DTLVardef@194e09aorg.highwire.dtl.DTLVardef@125b3c9_HPS_FORMAT_FIGEXP M_FIG C_FIG Schematic representation of the novel function and implication of PI5P4K in PDAC. PI5P4K is upregulated in PDAC to support the ferro-addiction and heightened metabolic requirements of the tumor. When PI5P4K is inhibited, the PDAC cells undergo apoptotic cell death due to iron depletion. PI5P4K-depleted PDAC cells upregulate autophagy as an adaptive response but is not sufficient to defend against apoptotic cell death.

cancer biology↗

Sex-dependent macromolecule and nanoparticle delivery in experimental brain injury

Development of effective therapeutics for brain disorders is challenging, in particular, the blood-brain barrier (BBB) severely limits access of the therapeutics into the brain parenchyma. Traumatic brain injury (TBI) may lead to transient BBB permeability that affords a unique opportunity for therapeutic delivery via intravenous administration ranging from macromolecules to nanoparticles (NP) for developing precision therapeutics. In this regard, we address critical gaps in understanding the range/size of therapeutics, delivery window(s), and moreover the potential impact of biological factors for optimal delivery parameters. Here we show, for the first time, to the best of our knowledge, that 24 h post-focal TBI female mice exhibit a heightened macromolecular tracer and NP accumulation compared to male mice, indicating sex-dependent differences in BBB permeability. Furthermore, we report for the first time the potential to deliver NP-based therapeutics within 3 d after focal injury in both female and male mice. The delineation of injury-induced BBB permeability with respect to sex and temporal profile is essential to more accurately tailor time-dependent precision and personalized nanotherapeutics.

bioengineering↗

Hyperactive MEK1 signaling in cortical GABAergic interneurons causes embryonic parvalbumin-neuron death and deficits in behavioral inhibition

Abnormal ERK/MAPK pathway activity is an important contributor to the neuropathogenesis of many disorders including Fragile X, Rett, 16p11.2 Syndromes, and the RASopathies. Individuals with these syndromes often present with intellectual disability, ADHD, autism, and epilepsy. However, the pathological mechanisms that underly these deficits are not fully understood. Here, we examined whether hyperactivation of MEK1 signaling modifies the development of GABAergic cortical interneurons (CINs), a heterogeneous population of inhibitory neurons necessary for cortical function. We show that GABAergic-neuron specific MEK1 hyperactivation in vivo leads to increased cleaved caspase-3 labeling in a subpopulation of immature neurons in the embryonic subpallium. Adult mutants displayed a significant loss of mature parvalbumin-expressing (PV) CINs, but not somatostatin-expressing CINs, during postnatal development and a modest reduction in perisomatic inhibitory synapse formation on excitatory neurons. Surviving mutant PV-CINs maintained a typical fast-spiking phenotype and minor differences in intrinsic electrophysiological properties. These changes coincided with an increased risk of seizure-like phenotypes. In contrast to other mouse models of PV-CIN loss, we discovered a robust increase in the accumulation of perineuronal nets, an extracellular structure thought to restrict plasticity in the developing brain. Indeed, we found that mutants exhibit a significant impairment in the acquisition of a behavioral test that relies on behavioral response inhibition, a process linked to ADHD-like phenotypes. Overall, our data suggests PV-CIN development is particularly sensitive to hyperactive MEK1 signaling which may underlie neurological deficits frequently observed in ERK/MAPK-linked syndromes.\n\nSignificance StatementThe RASopathies are a family of neurodevelopmental syndromes caused by mutations that lead to increased RAS/RAF/MEK/ERK signaling and are associated with intellectual disability, epilepsy, and ADHD. We do not fully understand how distinct neuronal subtypes are affected in these syndromes. Here, we show that increased MEK signaling in developing mice promotes the embryonic death of a specific subset of cortical inhibitory neurons that express parvalbumin. Surviving mutant parvalbumin neurons also show significant changes in crucial maturation processes, which coincide with increased seizure susceptibility and profound deficits in behavioral inhibition. These data suggest that deficits in inhibitory circuit development contribute to RASopathy neuropathogenesis and indicate that therapeutic strategies targeting inhibitory interneuron dysfunction may be beneficial for these individuals.

neuroscience↗