Scholarly Works, Fralin Biomedical Research Institute at VTC

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AEOL-induced NRF2 activation and DWORF overexpression mitigate myocardial I/R injury
Asensio-Lopez, Maria del Carmen; Ruiz-Ballester, Miriam; Pascual-Oliver, Silvia; Bastida-Nicolas, Francisco J.; Sassi, Yassine; Fuster, Jose J.; Pascual-Figal, Domingo; Soler, Fernando; Lax, Antonio (2025-05-15)
Background: The causal relationship between the activation of nuclear factor erythroid 2-related factor 2 (NRF2) and the preservation of SERCA2a function in mitigating myocardial ischemia–reperfusion (mI/R) injury, along with the associated regulatory mechanisms, remains incompletely understood. This study aims to unravel how NRF2 directly or indirectly influences SERCA2a function and its regulators, phospholamban (PLN) and Dwarf Open Reading Frame (DWORF), by testing the pharmacological repositioning of AEOL-10150 (AEOL) in the context of mI/R injury. Methods C57BL6/J, Nrf2 knockout (Nrf2−/−), and wild-type (Nrf2+/+) mice, as well as human induced pluripotent stem cell-derived cardiomyocytes (hiPSCMs) were subjected to I/R injury. Gain/loss of function techniques, RT-qPCR, western blotting, LC/MS/MS, and fluorescence spectroscopy were utilized. Cardiac dimensions and function were assessed by echocardiography. Results: In the early stages of mI/R injury, AEOL administration reduced mitochondrial ROS production, decreased myocardial infarct size, and improved cardiac function. These effects were due to NRF2 activation, leading to the overexpression of the micro-peptide DWORF, consequently enhancing SERCA2a activity. The cardioprotective effect induced by AEOL was diminished in Nrf2−/− mice and in Nrf2/Dworf knockdown models in hiPSCMs subjected to simulated I/R injury. Our data show that AEOL-induced NRF2-mediated upregulation of DWORF disrupts the phospholamban-SERCA2a interaction, leading to enhanced SERCA2a activation and improved cardiac function. Conclusions: Taken together, our study reveals that AEOL-induced NRF2-mediated overexpression of DWORF enhances myocardial function through the activation of the SERCA2a offering promising therapeutic avenues for mI/R injury.
Red blood cell aggregation within a blood clot causes platelet-independent clot shrinkage
Peshkova, Alina; Rednikova, Ekaterina; Khismatullin, Rafael; Kim, Oleg; Muzykantov, Vladimir; Purohit, Prashant; Litvinov, Rustem; Weisel, John (American Society of Hematology, 2025-04-16)
Platelet-driven blood clot contraction (retraction) is important for hemostasis and thrombosis. RBCs occupy about half of the clot volume, but their possible active contribution to contraction is unknown. The work was aimed at elucidating the ability of RBCs to promote clot shrinkage. To distinguish effects of platelets and RBCs, we formed thrombin-induced clots from reconstituted human samples containing platelet-free plasma and platelet-depleted RBCs, followed by tracking the clot size. The clots before and after RBC-induced shrinkage were analyzed using histology and scanning electron microscopy. Tension developed in the RBC-containing plasma clots was measured with rheometry and theoretical modeling was used to elucidate the clot shrinkage mechanisms. Platelet-depleted clots formed in the presence of RBCs exhibited >20% volume shrinkage within one hour. This process was insensitive to blebbistatin, latrunculin A, and abciximab. At a higher RBC count clot shrinkage increased, whereas in the absence of RBCs no plasma clot shrinkage was observed. At low platelet counts RBCs stimulated clot contraction proportionately to the platelet level. Inside the shrunken clots, RBCs formed aggregates. The average tensile force per one RBC was ~120±100 pN. Clots from purified fibrinogen formed in the presence of RBCs did not change in size, but underwent shrinkage in the presence of osmotically active dextran. Blood clot shrinkage can be caused by RBCs alone and this effect is due to the RBC aggregation driven mainly by osmotic depletion. The RBC-induced clot shrinkage may reinforce platelet-driven blood clot contraction and promote clot compaction when there are few and/or dysfunctional platelets.
Transient Lymphatic Remodeling Follows Sub‑Ablative High‑Frequency Irreversible Electroporation Therapy in a 4T1 Murine Model
Esparza, Savieay; Jacobs, Edward; Hammel, Jennifer H.; Michelhaugh, Sharon K.; Alinezhadbalalami, Nastaran; Nagai‑Singer, Margaret; Imran, Khan Mohammad; Davalos, Rafael V.; Allen, Irving C.; Verbridge, Scott S.; Munson, Jennifer M. (Springer, 2025-02-25)
High-frequency irreversible electroporation (H-FIRE) is a minimally invasive local ablation therapy known to activate the adaptive immune system and reprogram the tumor microenvironment. Its predecessor, irreversible electroporation (IRE), transiently increases microvascular density and immune cell infiltration within the surviving non-ablated and non-necrotic tumor region, also known as the viable tumor region. However, the impact of pulse electric field therapies on lymphatic vessels, crucial for T-cell fate and maturation, remains unclear. This study investigates how sub-ablative H-FIRE (SA-HFIRE) affects lymphatic and blood microvascular remodeling in the 4T1 mammary mouse model. We conducted a temporal and spatial analysis to evaluate vascular changes in the viable tumor, peritumoral fat pad, and tumor-draining lymph node posttreatment. Histological examination showed a transient increase in blood vessel density on Day 1 post-treatment, followed by a spike in lymphatic vessel density in the viable tumor region on Day 3 post-treatment, increased lymphatic vessel density in the peripheral fat pad, and minimal remodeling of the tumor-draining lymph node within 3 days following treatment. Gene expression analysis indicated elevated levels of CCL21 and CXCL2 on Day 1 post-treatment, while VEGFA and VEGFC did not appear to contribute to vascular remodeling. Likewise, CCL21 protein content in tumor-draining axillary lymph nodes correlated with gene expression data from the viable tumor region. These findings suggest a dynamic shift in lymphatic and blood microvascular structures post-SA-HFIRE, potentially enhancing the adaptive immune response through CCL21- mediated lymphatic homing and subsequent lymph node microvascular remodeling. Future work will assess the immune and transport function of the microvasculature to inform experiments aimed at the application of adjuvant therapies during scenarios of tumor partial ablation.
Clinical use of ACQUIRE Therapy for Children Diagnosed With CASK-Gene Related Disabilities
Wallace, Dory A.; Trucks, Mary Rebekah; DeLuca, Stephanie C. (Sage, 2024-11)
Objective: To report practice based evidence built on clinical findings where an intensive therapeutic approach called ACQUIRE Therapy was used as a rehabilitation/habilitation tool for children diagnosed with CASK mutations. ACQUIRE Therapy delivery is based on principles of learning and guided by a therapeutic framework often used in the delivery of intensive therapy. Design: Clinical Cohort. Setting: Natural environments (e.g., home-like environment). Participants: A total of 20 females, 12 to 128 months, mean age = 44.75 (SD = 31.64). Intervention: Trained Occupational therapists delivered high-dosage rehabilitation for an average of 64.06 hours (SD = 12.91) across 4 weeks. ACQUIRE Therapy targeted cross-domain intervention targets often associated with executive control and praxis. Main outcome measures: Clinical data was examined from the following sources; therapist daily treatment documentation (eg, therapy goals, video recordings, daily therapy logs, and discharge documentation). Results: Receptive communication improved in all children. The most common motor skill improvements occurred in trunk control occurring in 33% of children; followed by, gross reaching abilities in 21% of children; fine-motor skills in 19%; head control in 15%; and mobility in 12%. Documentation of cognitive-motor pairing of skills was documented in all children. Conclusions: Diagnosis specific intervention targets (eg, attention and cognitive-pairing skills) need to be considered when providing therapeutic services to children with CASK-gene mutations and other forms of Global Developmental Delay.
Oral dosage forms for drug delivery to the colon: an existing gap between research and commercial applications
Martínez, Estefanía; Gamboa, Jennifer; Finkielstein, Carla V.; Cañas, Ana I.; Osorio, Marlon A.; Vélez, Yesid; Llinas, Néstor; Castro, Cristina I. (2025-03-05)
Oral drug administration is the preferred route for pharmaceuticals, accounting for ~90% of the global pharmaceutical market due to its convenience and cost-effectiveness. This study provides a comprehensive scientific and technological analysis of the latest advances in oral dosage forms for colon-targeted drug delivery. Utilizing scientific and patent databases, along with a bibliometric analysis and bibliographical review, we compared the oral dosage forms (technology) with the specific application of the technology (colon delivery) using four search equations. Our findings reveal a gap in the publications and inventions associated with oral dosage forms for colon release compared to oral dosage forms for general applications. While tablets and capsules were found the most used dosage forms, other platforms such as nanoparticles, microparticles, and emulsions have been also explored. Enteric coatings are the most frequently applied excipient to prevent the early drug release in the stomach with pH-triggered systems being the predominant release mechanism. In summary, this review provides a comprehensive analysis of the last advancements and high-impact resources in the development of oral dosage forms for colon-targeted drug delivery, providing insights into the technological maturity of these approaches.
Neural Signatures of Cognitive Control Predict Future Adolescent Substance Use Onset and Frequency
Chen, Ya-Yun; Lindenmuth, Morgan; Lee, Tae-Ho; Lee, Jacob; Casas, Brooks; Kim-Spoon, Jungmeen (Elsevier, 2024-11-29)
BACKGROUND: Adolescent substance use is a significant predictor of future addiction and related disorders. Understanding neural mechanisms underlying substance use initiation and frequency during adolescence is critical for early prevention and intervention. METHODS: The current longitudinal study followed 91 substance-naïve adolescents annually for 7 years from ages 14 to 21 years to identify potential neural precursors that predict substance use initiation and frequency. Cognitive control processes were examined using the Multi-Source Interference Task to assess functional neural connectivity. A questionnaire was used to assess substance use frequency. RESULTS: Stronger connectivity between the dorsal anterior cingulate cortex (dACC) and dorsolateral prefrontal cortex (dlPFC) at time 1 predicted a delayed onset of substance use, indicative of a protective effect. A notable decline in this dACC–dlPFC connectivity was observed 1 year prior to substance use initiation. Conversely, lower connectivity of the dACC with the supplementary motor area and heightened connectivity of the anterior insula with the dorsal medial prefrontal cortex and angular gyrus were predictive of greater frequency of future substance use. These findings remained after controlling for demographic and socioeconomic covariates. CONCLUSIONS: This study highlights the critical role of cognitive control–related neural connectivity in predicting substance use initiation and frequency during adolescence. The results imply that efforts to strengthen and monitor the development of the top-down cognitive control system in the brain from early adolescence can be protective and deter progression into problematic substance use. Furthermore, for adolescents with heightened frequency of substance use, interventions may prove more effective by targeting interoceptive processes in cognitive control training.
Psychopathology as long-term sequelae of maltreatment and socioeconomic disadvantage: Neurocognitive development perspectives
Kim-Spoon, Jungmeen; Brieant, Alexis; Folker, Ann; Lindenmuth, Morgan; Lee, Jacob; Casas, Brooks; Deater-Deckard, Kirby (Cambridge University Press, 2024-03-13)
Neuroscience research underscores the critical impact of adverse experiences on brain development. Yet, there is limited understanding of the specific pathways linking adverse experiences to accelerated or delayed brain development and their ultimate contributions to psychopathology. Here, we present new longitudinal data demonstrating that neurocognitive functioning during adolescence, as affected by adverse experiences, predicts psychopathology during young adulthood. The sample included 167 participants (52% male) assessed in adolescence and young adulthood. Adverse experiences were measured by early maltreatment experiences and low family socioeconomic status. Cognitive control was assessed by neural activation and behavioral performance during the Multi-Source Interference Task. Psychopathology was measured by self-reported internalizing and externalizing symptomatology. Results indicated that higher maltreatment predicted heightened frontoparietal activation during cognitive control, indicating delayed neurodevelopment, which, in turn predicted higher internalizing and externalizing symptomatology. Furthermore, higher maltreatment predicted a steeper decline in frontoparietal activation across adolescence, indicating neural plasticity in cognitive control-related brain development,which was associated with lower internalizing symptomatology. Our results elucidate the crucial role of neurocognitive development in the processes linking adverse experiences and psychopathology. Implications of the findings and directions for future research on the effects of adverse experiences on brain development are discussed.
Long-Term Effects of Adverse Maternal Care on Hypothalamic–Pituitary–Adrenal (HPA) Axis Function of Juvenile and Adolescent Macaques
McCormack, Kai; Bramlett, Sara; Morin, Elyse L.; Siebert, Erin R.; Guzman, Dora; Howell, Brittany; Sanchez, Mar M. (MDPI, 2025-02-15)
Early life adversity (ELA) is a known risk factor for psychopathology, including stress-related anxiety and depressive disorders. The underlying mechanisms and developmental changes remain poorly understood. A likely underpinning is the impact of ELA on the development of stress response systems, including the hypothalamic–pituitary–adrenal (HPA) axis. Our group studied a translational ELA model of spontaneous infant maltreatment by the mother in rhesus macaques, where we used a cross-fostering design to randomly assign infant macaques to either Control or Maltreating (MALT) foster mothers at birth to examine the impact of adverse caregiving on the development of the HPA axis, while controlling for the confounding effects of heritable and prenatal factors. We previously reported higher levels of plasma and hair cortisol (CORT) across the first 6 postnatal months (equivalent to the first 2 years of life in humans) in the MALT than in the Control infants. Here, we followed the same cohort of infants longitudinally to assess the long-term developmental impact of this adverse experience on HPA axis function during the juvenile (12, 18 months) and late adolescent (~5 years) periods. For this, we collected measurements of diurnal CORT rhythm and glucocorticoid negative feedback using the dexamethasone suppression test (DST). At 12 months, we found higher diurnal CORT secretion in MALT females compared to Control females, and impaired negative feedback in response to the DST in both sexes in the MALT group. However, ELA group differences in the HPA axis function disappeared by 18 months and late adolescence, while sex differences in diurnal CORT rhythm emerged or became stronger. These results suggest that infant maltreatment causes dysregulation of the HPA axis during the first year of life, with HPA axis function normalizing later, during the pre-pubertal juvenile period and adolescence. This suggests that the impact of maltreatment on HPA axis function may be transient, at least if the adverse experience stops. Our findings are consistent with human evidence of recalibration/normalization of HPA axis function during adolescence in children that switch from adverse/deprived environments to supportive adoptive families. This research has broad implications regarding the biological processes that translate ELA to psychopathology during development and the pathways to resiliency.
Synthetic cationic helical polypeptides for the stimulation of antitumour innate immune pathways in antigen-presenting cells
Lee, DaeYong; Huntoon, Kristin; Wang, Yifan; Kang, Minjeong; Lu, Yifei; Jeong, Seong Dong; Link, Todd M.; Gallup, Thomas D.; Qie, Yaqing; Li, Xuefeng; Dong, Shiyan; Schrank, Benjamin R.; Grippin, Adam J.; Antony, Abin; Ha, Jonghoon; Chang, Mengyu; An, Yi; Wang, Liang; Jiang, Dadi; Li, Jing; Koong, Albert C.; Tainer, John A.; Jiang, Wen; Kim, Betty Y. S. (Nature Portfolio, 2024-04-19)
Intracellular DNA sensors regulate innate immunity and can provide a bridge to adaptive immunogenicity. However, the activation of the sensors in antigen-presenting cells (APCs) by natural agonists such as double-stranded DNAs or cyclic nucleotides is impeded by poor intracellular delivery, serum stability, enzymatic degradation and rapid systemic clearance. Here we show that the hydrophobicity, electrostatic charge and secondary conformation of helical polypeptides can be optimized to stimulate innate immune pathways via endoplasmic reticulum stress in APCs. One of the three polypeptides that we engineered activated two major intracellular DNA-sensing pathways (cGAS-STING (for cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes) and Toll-like receptor 9) preferentially in APCs by promoting the release of mitochondrial DNA, which led to the efficient priming of effector T cells. In syngeneic mouse models of locally advanced and metastatic breast cancers, the polypeptides led to potent DNA-sensor-mediated antitumour responses when intravenously given as monotherapy or with immune checkpoint inhibitors. The activation of multiple innate immune pathways via engineered cationic polypeptides may offer therapeutic advantages in the generation of antitumour immune responses.
MCU expression in hippocampal CA2 neurons modulates dendritic mitochondrial morphology and synaptic plasticity
Pannoni, Katy E.; Fischer, Quentin S.; Tarannum, Renesa; Cawley, Mikel L.; Alsalman, Mayd M.; Acosta, Nicole; Ezigbo, Chisom; Gil, Daniela V.; Campbell, Logan A.; Farris, Shannon (Nature Research, 2025-02-06)
Neuronal mitochondria are diverse across cell types and subcellular compartments in order to meet unique energy demands. While mitochondria are essential for synaptic transmission and synaptic plasticity, the mechanisms regulating mitochondria to support normal synapse function are incompletely understood. The mitochondrial calcium uniporter (MCU) is proposed to couple neuronal activity to mitochondrial ATP production, which would allow neurons to rapidly adapt to changing energy demands. MCU is uniquely enriched in hippocampal CA2 distal dendrites compared to proximal dendrites, however, the functional significance of this layer-specific enrichment is not clear. Synapses onto CA2 distal dendrites readily express plasticity, unlike the plasticity-resistant synapses onto CA2 proximal dendrites, but the mechanisms underlying these different plasticity profiles are unknown. Using a CA2-specific MCU knockout (cKO) mouse, we found that MCU deletion impairs plasticity at distal dendrite synapses. However, mitochondria were more fragmented and spine head area was diminished throughout the dendritic layers of MCU cKO mice versus control mice. Fragmented mitochondria might have functional changes, such as altered ATP production, that could explain the structural and functional deficits at cKO synapses. Differences in MCU expression across cell types and circuits might be a general mechanism to tune mitochondrial function to meet distinct synaptic demands.
Circadian clock gene polymorphisms implicated in human pathologies
Janoski, Jesse R.; Aiello, Ignacio; Lundberg, Clayton W.; Finkielstein, Carla V. (Cell Press, 2024-06-12)
Circadian rhythms, ~24 h cycles of physiological and behavioral processes, can be synchronized by external signals (e.g., light) and persist even in their absence. Consequently, dysregulation of circadian rhythms adversely affects the well-being of the organism. This timekeeping system is generated and sustained by a genetically encoded endogenous mechanism composed of interlocking transcriptional/translational feedback loops that generate rhythmic expression of core clock genes. Genome-wide association studies (GWAS) and forward genetic studies show that SNPs in clock genes influence gene regulation and correlate with the risk of developing various conditions. We discuss genetic variations in core clock genes that are associated with various phenotypes, their implications for human health, and stress the need for thorough studies in this domain of circadian regulation.
Durotaxis and extracellular matrix degradation promote clustering of cancer cells
Potomkin, Mykhailo; Kim, Oleg V.; Klymenko, Yuliya; Alber, Mark; Aronson, Igor S. (Elsevier, 2025-01-24)
Early stages of metastasis depend on the collective behavior of cancer cells and their interaction 23 with the extracellular matrix (ECM). Cancer cell clusters are known to exhibit higher metastatic 24 potential than single cells. To explore clustering dynamics, we developed a calibrated computa- 25 tional model describing how motile cancer cells biochemically and biomechanically interact with 26 the ECM during the initial invasion phase, including ECM degradation and mechanical remod- 27 eling. The model reveals that cluster formation time, size, and shape are influenced by ECM 28 degradation rates and cellular responsiveness to external stresses (durotaxis). The results align 29 with experimental observations, demonstrating distinct cell trajectories and cluster morphologies 30 shaped by biomechanical parameters. These simulations provide valuable insights into cancer 31 invasion dynamics and may suggest potential therapeutic strategies targeting early-stage inva- 32 sive cells.
Reinforcement learning processes as forecasters of depression remission
Bansal, Vansh; McCurry, Katherine L.; Lisinski, Jonathan; Kim, Dong-Youl; Goyal, Shivani; Wang, John M.; Lee, Jacob; Brown, Vanessa M.; LaConte, Stephen M.; Casas, Brooks; Chiu, Pearl H. (Elsevier, 2024-09-11)
Background: Aspects of reinforcement learning have been associated with specific depression symptoms and may inform the course of depressive illness. Methods: We applied support vector machines to investigate whether blood‑oxygen-level dependent (BOLD) responses linked with neural prediction error (nPE) and neural expected value (nEV) from a probabilistic learning task could forecast depression remission. We investigated whether predictions were moderated by treatment use or symptoms. Participants included 55 individuals (n = 39 female) with a depression diagnosis at baseline; 36 of these individuals completed standard cognitive behavioral therapy and 19 were followed during naturalistic course of illness. All participants were assessed for depression diagnosis at a follow-up visit. Results: Both nPE and nEV classifiers forecasted remission significantly better than null classifiers. The nEV classifier performed significantly better than the nPE classifier. We found no main or interaction effects of treatment status on nPE or nEV accuracy. We found a significant interaction between nPE-forecasted remission status and anhedonia, but not for negative affect or anxious arousal, when controlling for nEV-forecasted remission status. Limitations: Our sample size, while comparable to that of other studies, limits options for maximizing and evaluating model performance. We addressed this with two standard methods for optimizing model performance (90:10 train and test scheme and bootstrapped sampling). Conclusions: Results support nEV and nPE as relevant biobehavioral signals for understanding depression outcome independent of treatment status, with nEV being stronger than nPE as a predictor of remission. Reinforcement learning variables may be useful components of an individualized medicine framework for depression healthcare.
Stabilizing milk-derived extracellular vesicles (mEVs) through lyophilization: a novel trehalose and tryptophan formulation for maintaining structure and Bioactivity during long-term storage
Dogan, Alan B.; Marsh, Spencer R.; Tschetter, Rachel J.; Beard, Claire E.; Amin, Md R.; Jourdan, L. Jane; Gourdie, Robert G. (2025-01-13)
Extracellular vesicles (EVs) are widely investigated for their implications in cell-cell signaling, immune modulation, disease pathogenesis, cancer, regenerative medicine, and as a potential drug delivery vector. However, maintaining integrity and bioactivity of EVs between Good Manufacturing Practice separation/filtration and end-user application remains a consistent bottleneck towards commercialization. Milk-derived extracellular vesicles (mEVs), separated from bovine milk, could provide a relatively low-cost, scalable platform for large-scale mEV production; however, the reliance on cold supply chain for storage remains a logistical and financial burden for biologics that are unstable at room temperature. Herein, we aim to characterize and engineer a freeze-dried, mEV formulation that can be stored at room temperature without sacrificing structure/bioactivity and can be reconstituted before delivery. In addition to undertaking established mEV assays of structure and function on our preparations, we introduce a novel, efficient, high throughput assay of mEV bioactivity based on Electric Cell Substrate Impedance Sensing (ECIS) in Human dermal fibroblast monolayers. By adding appropriate excipients, such as trehalose and tryptophan, we describe a protective formulation that preserves mEV bioactivity during long-term, room temperature storage. Our identification of the efficacy of tryptophan as a novel additive to mEV lyophilization solutions could represent a significant advancement in stabilizing small extracellular vesicles outside of cold storage conditions.
Emotional words evoke region- and valence-specific patterns of concurrent neuromodulator release in human thalamus and cortex
Batten, Seth R.; Hartle, Alec E.; Barbosa, Leonardo S.; Hadj-Amar, Beniamino; Bang, Dan; Melville, Natalie; Twomey, Tom; White, Jason P.; Torres, Alexis; Celaya, Xavier; McClure, Samuel M.; Brewer, Gene A.; Lohrenz, Terry; Kishida, Kenneth T.; Bina, Robert W.; Witcher, Mark R.; Vannucci, Marina; Casas, Brooks; Chiu, Pearl; Montague, P. Read; Howe, William M. (Elsevier, 2025-01-28)
Words represent a uniquely human information channel—humans use words to express thoughts and feelings and to assign emotional valence to experience. Work from model organisms suggests that valence assignments are carried out in part by the neuromodulators dopamine, serotonin, and norepinephrine. Here, we ask whether valence signaling by these neuromodulators extends to word semantics in humans by measuring sub-second neuromodulator dynamics in the thalamus (N = 13) and anterior cingulate cortex (N = 6) of individuals evaluating positive, negative, and neutrally valenced words. Our combined results suggest that valenced words modulate neuromodulator release in both the thalamus and cortex, but with regionand valence-specific response patterns, as well as hemispheric dependence for dopamine release in the anterior cingulate. Overall, these experiments provide evidence that neuromodulator-dependent valence signaling extends to word semantics in humans, but not in a simple one-valence-per-transmitter fashion.
Molecular Basis of Oncogenic PI3K Proteins
Sheng, Zhi; Beck, Patrick; Gabby, Maegan; Habte-Mariam, Semhar; Mitkos, Katherine (MDPI, 2024-12-30)
The dysregulation of phosphatidylinositol 3-kinase (PI3K) signaling plays a pivotal role in driving neoplastic transformation by promoting uncontrolled cell survival and proliferation. This oncogenic activity is primarily caused by mutations that are frequently found in PI3K genes and constitutively activate the PI3K signaling pathway. However, tumorigenesis can also arise from nonmutated PI3K proteins adopting unique active conformations, further complicating the understanding of PI3K-driven cancers. Recent structural studies have illuminated the functional divergence among highly homologous PI3K proteins, revealing how subtle structural alterations significantly impact their activity and contribute to tumorigenesis. In this review, we summarize current knowledge of Class I PI3K proteins and aim to unravel the complex mechanism underlying their oncogenic traits. These insights will not only enhance our understanding of PI3K-mediated oncogenesis but also pave the way for the design of novel PI3K-based therapies to combat cancers driven by this signaling pathway.
Cerebellar nuclei cells produce distinct pathogenic spike signatures in mouse models of ataxia, dystonia, and tremor
van der Heijden, Meike E.; Brown, Amanda M.; Kizek, Dominic J.; Sillitoe, Roy (eLife, 2024-07-29)
The cerebellum contributes to a diverse array of motor conditions, including ataxia, dystonia, and tremor. The neural substrates that encode this diversity are unclear. Here, we tested whether the neural spike activity of cerebellar output neurons is distinct between movement disorders with different impairments, generalizable across movement disorders with similar impairments, and capable of causing distinct movement impairments. Using in vivo awake recordings as input data, we trained a supervised classifier model to differentiate the spike parameters between mouse models for ataxia, dystonia, and tremor. The classifier model correctly assigned mouse phenotypes based on single-neuron signatures. Spike signatures were shared across etiologically distinct but phenotypically similar disease models. Mimicking these pathophysiological spike signatures with optogenetics induced the predicted motor impairments in otherwise healthy mice. These data show that distinct spike signatures promote the behavioral presentation of cerebellar diseases.
Converging and Diverging Cerebellar Pathways for Motor and Social Behaviors in Mice
van der Heijden, Meike E. (Springer, 2024-05-23)
Evidence from clinical and preclinical studies has shown that the cerebellum contributes to cognitive functions, including social behaviors. Now that the cerebellum’s role in a wider range of behaviors has been confirmed, the question arises whether the cerebellum contributes to social behaviors via the same mechanisms with which it modulates movements. This review seeks to answer whether the cerebellum guides motor and social behaviors through identical pathways. It focuses on studies in which cerebellar cells, synapses, or genes are manipulated in a cell-type specific manner followed by testing of the effects on social and motor behaviors. These studies show that both anatomically restricted and cerebellar cortex-wide manipulations can lead to social impairments without abnormal motor control, and vice versa. These studies suggest that the cerebellum employs different cellular, synaptic, and molecular pathways for social and motor behaviors. Future studies warrant a focus on the diverging mechanisms by which the cerebellum contributes to a wide range of neural functions.
More Than a Small Brain: The Importance of Studying Neural Function during Development
Dooley, James C.; van der Heijden, Meike E. (Society for Neuroscience, 2024-11-27)
The nervous system contains complex circuits comprising thousands of cell types and trillions of connections. Here, we discuss how the field of "developmental systems neuroscience" combines the molecular and genetic perspectives of developmental neuroscience with the (typically adult-focused) functional perspective of systems neuroscience. This combination of approaches is critical to understanding how a handful of cells eventually produce the wide range of behaviors necessary for survival. Functional circuit development typically lags behind neural connectivity, leading to intermediate stages of neural activity that are either not seen in adults or, if present, are considered pathophysiological. Developmental systems neuroscience examines these intermediate stages of neural activity, mapping out the critical phases and inflection points of neural circuit function to understand how neural activity and behavior emerge across development. Beyond understanding typical development, this approach provides invaluable insight into the pathophysiology of neurodevelopmental disorders by identifying when and how functional development diverges between health and disease. We argue that developmental systems neuroscience will identify important periods of neural development, reveal novel therapeutic windows for treatment, and set the stage to answer fundamental questions about the brain in health and disease.
Gradient descent optimization of acoustic holograms for transcranial focused ultrasound
Sallam, Ahmed; Cengiz, Ceren; Pewekar, Mihir; Hoffmann, Eric; Legon, Wynn; Vlaisavljevich, Eli; Shahab, Shima (AIP Publishing, 2024-10-08)
Acoustic holographic lenses, also known as acoustic holograms, can change the phase of a transmitted wavefront in order to shape and construct complex ultrasound pressure fields, often for focusing the acoustic energy on a target region. These lenses have been proposed for transcranial focused ultrasound (tFUS) to create diffraction-limited focal zones that target specific brain regions while compensating for skull aberration. Holograms are currently designed using time-reversal approaches in full-wave time-domain numerical simulations. Such simulations need time-consuming computations, which severely limits the adoption of iterative optimization strategies. In the time-reversal method, the number and distribution of virtual sources can significantly influence the final sound field. Because of the computational constraints, predicting these effects and determining the optimal arrangement is challenging. This study introduces an efficient method for designing acoustic holograms using a volumetric holographic technique to generate focused fields inside the skull. The proposed method combines a modified mixed-domain method for ultrasonic propagation with a gradient descent iterative optimization algorithm. The findings are further validated in underwater experiments with a realistic 3D-printed skull phantom. This approach enables substantially faster holographic computation than previously reported techniques. The iterative process uses explicitly defined loss functions to bias the ultrasound field’s optimization parameters to specific desired characteristics, such as axial resolution, transversal resolution, coverage, and focal region uniformity, while eliminating the uncertainty associated with virtual sources in time-reversal techniques. The proposed techniques enable more rapid hologram computation and more flexibility in tailoring ultrasound fields for specific therapeutic requirements.

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