Biology subjects

Lee, N. S.

Publications and source records attributed to Lee, N. S..

6 recordsLinked to original sources

bioRxiv2026

Transcription Factor-Mediated Reprogramming of Cancer-Associated Fibroblasts Reveals Targetable Vulnerabilities in Solid Tumors

Cancer-associated fibroblasts (CAFs) contribute to immune exclusion and therapy resistance in solid tumors, limiting the efficacy of chimeric antigen receptor (CAR) T cell and immune cell therapy. To overcome this, we developed a transcription factor (TF)-based strategy to reprogram prostate-derived CAFs (pCAFs) into normal fibroblast-like cells (NFs). We prioritized TFs enriched in quiescent stellate cells--Vitamin D receptor (VDR), Peroxisome Proliferator-Activated Receptor gamma (PPAR{gamma}), and p53--and selected VDR for proof-of-concept studies. Lentiviral VDR expression in pCAFs produced VDR-reprogrammed NFs (VDR-rpNFs) with reduced CAF markers, increased ATP, and suppressed TGF-{beta} and IL6, indicating phenotypic and metabolic reversion. In both in vitro 3D co-cultures and in vivo, VDR-rpNFs disrupted tumor architecture, enhanced CAR T cell infiltration, and reduced necrosis. PPAR{gamma}- and p53-rpNFs showed similar reprogramming effects. These results suggest TF-guided fibroblast reprogramming as a viable strategy to remodel the tumor microenvironment and improve CAR T cell efficacy in solid tumors.

cancer biology↗

bioRxiv2025

Multiple ammonium transporters in fission yeast are coordinated by transcriptional and localization regulation in response to nitrogen starvation

Ammonium is a preferred nitrogen source for microorganisms. We investigated the regulation of ammonium transporters Amt1, Amt2, and Amt3 in the fission yeast Schizosaccharomyces pombe. Expression of the amt1+ gene increases under nitrogen starvation as well as in the TORC1-deficient mutant tor2-287, suggesting the negative regulation of amt1+ by TORC1. This regulation depends on the GATA transcription factor Gaf1, whose phosphorylation is regulated by Ppe1 and PP2A phosphatases. Ppe1 is required for the nuclear accumulation of Gaf1, partly contributing to the controlled expression of amt1+. On the other hand, PP2A phosphatase is essential for the amt1+ induction upon starvation, indicating distinct roles for Ppe1 and PP2A in Gaf1 regulation. Nitrogen starvation also promotes the plasma membrane translocation of Amt1 and Amt2 in a manner dependent on the Tsc-Rhb1 pathway. Intriguingly, the amt1{Delta} amt2{Delta} tsc{Delta} mutant is more sensitive to low-ammonium conditions than the amt1{Delta} amt2{Delta} amt3{Delta} triple mutant. Thus, there may be an unidentified ammonium transporter whose plasma membrane localization is also dependent on the Tsc-Rhb1 pathway.

cell biology↗

bioRxiv2025

Structural basis for proton inhibition of the two-pore domain K+ channel TASK-1

TASK-1 is a pH-sensitive two-pore domain K+ channel inhibited by external protons. TASK-1 is widely expressed, including in cardiomyocytes and chemosensitive neurons in the brain. Altered channel expression and activity are implicated in diseases including atrial fibrillation, pulmonary arterial hypertension, and developmental delay with sleep apnea. Structures of TASK-1 have been captured with an open external and closed internal gate. The structural basis for external proton inhibition and potential for communication between inner and outer gates are incompletely understood. Here, we determine a cryo-EM structure of TASK-1 at low pH with a closed extracellular gate and assess pH sensitivity of mutated channels. Proton inhibition of TASK-1 involves a C-type selectivity filter gate similar to TASK-3, but distinct from other proton-inhibited K2Ps TASK-2 and TWIK-1. Protonation of an extracellular histidine leads to formation of a hydrophobic seal above the selectivity filter and dilation of the outer two K+ coordination sites to close the channel pore. We find that a pulmonary arterial hypertension-associated loss-of-function mutation near the outer gate increases proton sensitivity, while gain-of-function mutations near the inner X-gate and intracellular cavity reduce proton sensitivity. These data reveal the structural basis for extracellular pH-gating of TASK-1, suggest allosteric communication between the inner and outer gates, and illustrate differences in C-type gating among related K+ channels.

biophysics↗

bioRxiv2024

Tumor Priming by Ultrasound Mechanogenetics for with SynNotch CAR T Therapy

Cell-based cancer immunotherapy holds potential as a therapeutic approach, yet its application for solid tumor treatment remains challenging. We created a system where focused ultrasound (FUS) is able to remotely stimulate gene expressions in a specific tissue area through mechanical induction, gated by a chemical inducer to minimize the background noise. This system, known as CaDox, integrates FUS-triggered mechanical and calcium stimulation with doxycycline-responsive genetic circuits, which allows the localized expression of the clinically validated and specific antigen CD19 within a subpopulation of cancer cells upon FUS stimulation. These CD19-expressing cells can then function as "training centers" that activate synNotch chimeric antigen receptor (CAR) T cells to generate CARs that recognize a less specific but widespread antigen in cancer cells, thereby attacking and suppress the whole cancer cell population nearby at the tumor site. We validated the functionality of this CaDox system in vitro, in organoids, and in vivo, demonstrating its potential for various cell types and as a versatile platform for precisely controllable immunotherapy. Our combinatorial approach thus offers a FUS-controlled remote and non-invasive priming of solid tumors for effective and safe CAR T immunotherapy via the induced production of clinically validated antigens.

synthetic biology↗

bioRxiv2021

Social selectivity and social motivation in voles

Selective relationships are fundamental to humans and many other animals, but relationships between mates, family members, or peers may be mediated differently. We examined connections between social reward and social selectivity, aggression, and oxytocin receptor signaling pathways in rodents that naturally form enduring, selective relationships with mates and peers (prairie voles) or peers (meadow voles). Female prairie and meadow voles worked harder to access familiar vs. unfamiliar individuals, regardless of sex, and huddled extensively with familiar subjects. Male prairie voles also displayed strongly selective huddling preferences for familiar animals, but worked hardest to repeatedly access females vs. males, with no difference in effort by familiarity. This demonstrates a fundamental disconnect between motivation and social selectivity in males, and reveals a striking sex difference in pathways underlying social monogamy. Meadow voles exhibited social preferences but low social motivation, consistent with tolerance rather than reward supporting social groups in this species. Natural variation in oxytocin receptor genotype was associated with oxytocin receptor density, and both genotype and receptor binding predicted individual variation in prosocial and aggressive behaviors. These results provide a basis for understanding species, sex, and individual differences in the mechanisms underlying the role of social reward in social preference.

neuroscience↗

bioRxiv2020

Focused ultrasound stimulates ER localized mechanosensitive PANNEXIN-1 to mediate intracellular calcium release in invasive cancer cells

Focused ultrasound (FUS) is a rapidly developing stimulus technology with the potential to uncover novel mechanosensory dependent cellular processes. Since it is noninvasive, it holds great promise for future therapeutic applications in patients used either alone or as a complement to boost existing treatments. For example, FUS stimulation causes invasive but not noninvasive cancer cell lines to exhibit marked activation of calcium signaling pathways. Here, we identify the membrane channel PANNEXIN1 (PANX1) as a mediator for activation of calcium signaling in invasive cancer cells. Knockdown of PANX1 decreases calcium signaling in invasive cells, while PANX1 overexpression enhances calcium elevations in non-invasive cancer cells. We demonstrate that FUS may directly stimulate mechanosensory PANX1 localized in endoplasmic reticulum to evoke calcium release from internal stores. This process does not depend on mechanosensory stimulus transduction through an intact cytoskeleton and does not depend on plasma membrane localized PANX1. Plasma membrane localized PANX1 however plays a different role in mediating the spread of intercellular calcium waves via ATP release. Additionally, we show that FUS stimulation evokes cytokine/chemokine release from invasive cancer cells, suggesting that FUS could be an important new adjuvant treatment to improve cancer immunotherapy.

cell biology↗