Biology subjects

Lee, R. J.

Publications and source records attributed to Lee, R. J..

At least 19 recordsLinked to original sources

bioRxiv2026

Targeting cyclic-AMP/phosphodiesterase signaling to quiet nasal tuft cell calcium responses

Background: Airway tuft cells, also called solitary chemosensory cells, are enriched in nasal polyps and are likely the main epithelial source of interleukin-25 (IL-25) in chronic rhinosinusitis with nasal polyps (CRSwNP). Tuft cells are activated through G protein-coupled receptors (GPCRs) that signal through Ca2+. These receptors may also lower cyclic AMP (cAMP), but whether the cAMP pathway can be used to suppress tuft cell responses is unknown. Methods: Ca2+ and cAMP were measured by live cell imaging in isolated Trpm5-GFP mouse nasal tuft cells, and Ca2+ responses were measured in primary human nasal epithelial air-liquid interface (ALI) cultures from patients with CRSwNP. Defensin and IL-25 release were measured by ELISA and ciliary beat frequency (CBF) by high-speed imaging. Phosphodiesterase (PDE) expression was assessed using publicly available single cell RNA sequencing datasets. Results: Agonists of bitter taste receptors (T2Rs), the succinate receptor SUCNR1, and the A1 adenosine receptor increased Ca2+ in GFP-positive mouse nasal tuft cells. T2R and A1 receptor stimulation also lowered cAMP, and these decreases were blocked by pertussis toxin. Glucose, which activates taste family 1 receptors, increased cAMP. Tuft cells were enriched for Pde2a. PDE2A-selective inhibitors (PF-05180999 and BAY 60-7550) increased cAMP and reduced agonist-evoked Ca2+ responses in mouse tuft cells. In human nasal ALIs, both compounds reduced denatonium-evoked Ca2+ responses, defensin release, and IL-25 release without increasing CBF. Conclusions: GPCRs that activate nasal tuft cells also lower cAMP, and by raising cAMP through PDE2A inhibition, tuft cell Ca2+ signaling and IL-25 release were reduced in vitro.

physiology↗

bioRxiv2026

The functional neuronal lipotype is specified by activity and PS synthesis using dietary and lysosomal inputs

Neurons maintain specialized membranes necessary for lifelong circuit function. While neuronal membranes thus contain unique lipidomes, how and why specific lipids become synaptically enriched remains mysterious. Here, we identify a conserved hallmark of mature neurons, phosphatidylserines containing omega-3 fatty acids (n-3 PS), which dynamically accumulate during synaptogenesis from Drosophila to humans. This neuronal lipotype depends on dietary n-3 and lysosomal catabolism mediated by Saposin, the phospholipase PLA2G15, and the lysophospholipid transporter spin/SPNS1. Reducing neuronal PS biosynthesis by targeting the PS synthase (Pss) caused lipidomic, synaptic, and behavioral deficits exacerbated by impaired glycerophospholipid catabolism. While dietary, lysosomal, and lipoprotein manipulations broadly altered n-3 levels, silencing developmental activity-templating neurons selectively reduced n-3 PS. Remarkably, pathogenic Pss variants lacking feedback inhibition similarly reduced n-3 PS and impaired circuit function. As n-3 PS is reduced during neurodegeneration but absent from iPSC-derived neurons, important relationships between lipotype and physiology may not be recapitulated in vitro.

neuroscience↗

bioRxiv2026

Ciliary regulation of melanogenesis unveils moonlighting roles for Joubert Syndrome proteins

We previously found that skin tone correlates with intronic polymorphisms influencing the expression of the Joubert Syndrome (JS) ciliopathy gene TMEM138, suggesting that primary cilia might regulate pigment production in skin melanocytes. Herein, we show that many ciliary proteins regulate basal pigmentation in wild-type mouse and human melanocytes by facilitating primary cilium-dependent Melanocortin-1 receptor signaling, and downstream activation of the Microphthalmia transcription factor and melanogenic gene expression. Additionally, we identify an extra-ciliary moonlighting role for TMEM138 and other JS proteins in endolysosomal organization required for the biogenesis of melanosomes, the pigment-producing lysosome-related organelle in melanocytes. Our results provide new mechanistic insights into the physiological regulation of pigmentation and suggest that JS-specific pathology might be mediated by ciliary-independent mechanisms.

cell biology↗

bioRxiv2026

MS4A8B regulates Orai1-dependent Ca2+ influx to control motile cilia function in human nasal epithelial cells

Motile cilia demonstrate coordinated beating to propel fluids across epithelial tissues, and changes to their beating frequency are largely regulated by intracellular second messengers including Ca2+. In the airway epithelium, ciliary beating is essential to mucociliary clearance. Mucociliary clearance involves trapping inhaled pathogens and irritants in sticky mucus lining the airways for motile cilia to sweep away contaminated mucus, preventing infection and reducing general airway inflammation. Many chronic respiratory diseases, including chronic rhinosinusitis and asthma, are characterized by an acquired ciliary dysfunction. Despite the importance of Ca2+ signaling in cilia physiology, the identity and molecular mechanisms governing localized ciliary Ca2+ transport remain poorly understood. MS4A8B is an uncharacterized cilia-localized transmembrane protein. Other MS4A homologs have been indirectly linked to Ca2+ signaling via uncharacterized mechanisms. Using primary human nasal epithelial cells differentiated at air-liquid interface, we demonstrated that MS4A8B regulates motile cilia function. MS4A8B knockdown impairs ciliary beating and impacts cilia structure. Live-cell imaging combined with genetic analysis revealed that MS4A8B potentiates Orai1-mediated Ca2+ influx. Co-immunoprecipitation and FRET microscopy in ectopic expression systems demonstrated that MS4A8B interacts with Orai1 channels. Orai1 was further identified to reside in motile cilia of primary human nasal epithelial cells, allowing ciliary beat frequency to be stimulated by Orai1 agonists including arachidonic acid. MS4A8B functional coupling with Orai1 acts as an autonomous cilia signaling network. Targeting this compartmentalized signaling pathway offers a novel therapeutic approach to restore or enhance mucociliary clearance in airway diseases.

physiology↗

bioRxiv2026

TAS2R10 Suppresses ABCG2 Transporter-Associated Chemoresistance and Enhances Cisplatin Sensitivity in Head and Neck Squamous Cell Carcinoma

Cisplatin resistance remains a major barrier in head and neck squamous cell carcinoma (HNSCC) treatment. ATP-binding cassette (ABC) transporters contribute to chemoresistance by limiting intracellular drug accumulation. Bitter taste receptor 10 (T2R10) has been implicated in ABC transporter regulation, but its role in HNSCC remains undefined. HNSCC cell lines were treated with T2R10-agonist caffeine (100 or 200 M), cisplatin, or a combination, and viability was assessed by crystal violet assay. T2R10 promoter activity and expression following caffeine exposure were evaluated using a promoter-driven mCherry reporter and RT-qPCR. ABC transporter expression was measured after caffeine treatment and T2R10 gene (TAS2R10) knockdown or overexpression. Associations between tumor TAS2R10 expression and survival were assessed using TCGA data through GEPIA2. Caffeine enhanced the cisplatin-associated reduction in viability in a cell line- and concentration-dependent manner, with the strongest effect seen in UM-SCC47. A significant effect was observed in FaDu at 200 M of caffeine, and minimal response in RPMI 2650. RPMI 2650 cells and FaDu cells exhibited lower baseline TAS2R10 expression and RPMI 2650 cells did not demonstrate enhanced cisplatin sensitivity following caffeine treatment. Caffeine treatment increased TAS2R10 promoter activity and expression and was associated with decreased ABCG2 expression. TAS2R10 knockdown increased ABCG2 and ABCF1 expression, whereas TAS2R10 overexpression reduced ABCG2 and ABCC1 expression. High tumor TAS2R10 expression was associated with improved disease-free survival (log-rank p=0.0071; HR=0.61) but not overall survival. Caffeine enhances cisplatin sensitivity in selected HNSCC models. Caffeine exposure is associated with increased TAS2R10 expression and reduced expression of chemoresistance-associated transporters, particularly ABCG2.

cancer biology↗

bioRxiv2026

When the brightest is not the best: illuminant estimation from the geometry of specular highlights

Colour constancy supports stable object-colour perception across changes in illumination. Illuminant colour can be inferred from white surfaces or specular highlights, and many models adopt a "brightest is white" heuristic to identify illuminant colour. We tested an alternative: observers use structured changes in the proximal image to locate highlights even when they are not the brightest elements. Using computer-rendered scenes, we manipulated the reliability of two cues--brightest element and highlight geometry. Each scene showed a single textured sphere lit by multiple point lights with identical spectra. The sphere had uniform spectral reflectance, while a noise texture attenuated the reflectance by a variable scale factor. We tested three specularity levels (matte, low, mid). Observers viewed a 1.5 s animation and judged whether chromatic changes reflected an illuminant or material change. Performance for matte surfaces was near chance but improved sharply with increasing specularity. Observers outperformed an ideal observer relying solely on the brightest element. When highlights landed on darker texture regions, performance improved further, contrary to the brightest-element prediction. Phase scrambling, which disrupted highlight geometry while preserving global statistics, substantially reduced performance. Overall, observers do not rely solely on the brightest element; they exploit diffuse-specular regularities to resolve surface-illuminant ambiguity.

neuroscience↗

bioRxiv2025

Quercetin as a Bitter Taste Receptor Agonist with Anticancer Effects in Head and Neck Cancer Cells

Background/ObjectivesQuercetin is a bitter compound with demonstrated anticancer effects in preclinical models of head and neck squamous cell carcinoma (HNSCC). In taste transduction, bitter compounds activate bitter taste receptors (T2Rs), a group of G protein-coupled receptors with downstream signaling that includes cytosolic calcium (Ca2+) release. T2Rs are expressed in HNSCC cells, where their activation induces apoptosis in vitro. Increased T2R expression in HNSCC also correlates with improved patient survival. The objective of this study was to investigate the role of quercetin as an anticancer T2R agonist in HNSCC cells in vitro and ex vivo. MethodsQuercetin-mediated Ca2+ responses were assessed using live cell Ca2+ imaging in the presence of the T2R14 antagonist LF1 and G-protein inhibitor YM-254980 (YM) in UM-SCC-47 and FaDu HNSCC cell lines. Cell viability was evaluated using crystal violet assays in cell lines and MTS assays in patient-derived tumor slices. Mitochondrial depolarization was measured with TMRE in the presence and absence of T2R pathway inhibitors. ResultsQuercetin induced a Ca2+ response in HNSCC cells, which was significantly reduced by LF1 and YM. Quercetin also decreased cell viability in vitro and showed a potential decrease in viability in tumor slices but was not statistically significant. Finally, quercetin caused mitochondrial depolarization, which was reduced in the presence of LF1 but not by YM. ConclusionsIn HNSCC cells, quercetin causes a Ca2+ response that is likely mediated by T2R14, decreases viability, and causes mitochondrial depolarization.

cancer biology↗

bioRxiv2025

T2R5 agonist phendione decreases cell viability and induces apoptosis in head and neck squamous cell carcinoma

Bitter taste receptors (T2Rs), a family of G-protein coupled receptors, are emerging as potential therapeutic targets in head and neck squamous cell carcinoma (HNSCC). Phendione, a known T2R5 agonist, has not been previously investigated in HNSCC. Here, we show that phendione activates endogenously expressed T2R5 in HNSCC cells and ex vivo tumor samples, inducing sustained calcium responses, reducing cell viability, and promoting apoptosis through a T2R5-dependent mechanism. Analysis of The Cancer Genome Atlas data revealed that high T2R5 expression in HNSCC tumors correlates with improved long-term disease-specific survival, suggesting a potential tumor-suppressive role for T2R5. These findings highlight T2R5 as a promising therapeutic target in HNSCC and support further investigation of phendione or other T2R5 agonists as potential anti-cancer agents.

cancer biology↗

bioRxiv2025

Glia phagocytose neuronal sphingolipids to infiltrate developing synapses

The complex morphologies of mature neurons and glia emerge through profound rearrangements of cell membranes during development. Despite being integral components of these membranes, it is unclear whether lipids might actively sculpt these morphogenic processes. By analyzing lipid levels in the developing fruit fly brain, we discover dramatic increases in specific sphingolipids coinciding with neural circuit establishment. Disrupting this sphingolipid bolus via genetic perturbations of sphingolipid biosynthesis and catabolism leads to impaired glial autophagy. Remarkably, glia can obtain sphingolipid precursors needed for autophagy by phagocytosing neurons. These precursors are then converted into specific long-chain ceramide phosphoethanolamines (CPEs), invertebrate analogs of sphingomyelin. These lipids are essential for glia to arborize and infiltrate the brain, a critical step in circuit maturation that when disrupted leads to reduced synapse numbers. Taken together, our results demonstrate how spatiotemporal tuning of sphingolipid metabolism during development plays an instructive role in programming brain architecture. HighlightsO_LIBrain sphingolipids (SLs) remodel to very long-chain species during circuit maturation C_LIO_LIGlial autophagy requires de novo SL biosynthesis coordinated across neurons and glia C_LIO_LIGlia evade a biosynthetic blockade by phagolysosomal salvage of neuronal SLs C_LIO_LICeramide Phosphoethanolamine is critical for glial infiltration and synapse density C_LI

neuroscience↗

bioRxiv2024

Effects of Pseudomonas aeruginosa pyocyanin and 1-hydroxyphenazine on intracellular calcium, mitochondrial function, and viability in human nasal epithelial cells

Pseudomonas aeruginosa is an opportunistic pathogen that produces phenazine metabolites pyocyanin and 1-hydroxyphenazine that have been suggested to have detrimental effects on mitochondrial function and reactive oxygen species (ROS) production. Prior studies have suggested activation of Ca2+ signaling by pyocyanin in an airway cell line, while others have shown apoptotic effects on cancer cells. Ca2+ is tightly linked to both normal mitochondrial function as well as mitochondrial ROS and apoptosis during mitochondrial Ca2+ overload. We found that pyocyanin but not 1-hydroxyphenazine induced both cytosolic and mitochondrial Ca2+ increases in RPMI 2650 and primary human nasal epithelial cells (HNEC). Similar results were seen in HNEC air-liquid interface (ALI) cells, but these cells did not display a cytosolic Ca2+ response after treatment with pyocyanin. In RPMI 2650, activation of PKC, ER Ca2+ release, and PLC inhibition, indicated potential GPCR activation from pyocyanin. Similarly, ROS production increased after treatment with pyocyanin, but not 1-hydroxyphenazine in all 3 cell types, but with stark differences in CF and non-CF ALIs. In HNEC ALI, pyocyanin reduced ciliary beat frequency (CBF) after 4 hours, while 1-hydroxpyhenazine did not. Despite this, both pyocyanin and 1-hydroxyphenazine decreased in cell viability in RPMI 2650 nasal carcinoma cells but not in HNEC at 24 hours. However, in both RPMI 2650 and HNEC, mitochondrial membrane potential acutely decreased after treatment with either pyocyanin or 1-hydroxyphenazine. Finally, 24-hour pyocyanin treatment decreased expression of ER stress genes in some cancer cells, but not in non-cancerous HNEC. Our data suggest that Ca2+ signaling is not required for acute effects of 1-hydroxyphenazine or pyocyanin on mitochondrial function. The greater sensitivity of RPMI 2650 cells to pyocyanin-induced and 1-hydroxyphenzine-induced cytotoxicity compared with primary cells suggests that these compounds might have some applicability in treating nasal squamous carcinomas or other types of head and neck squamous carcinomas. Although the exact mechanisms of pyocyanin induced apoptosis remains uncertain, the downregulation of the ER stress response may play a role.

physiology↗

bioRxiv2024

Pseudomonas aeruginosa metabolite 3-oxo-C12HSL induces apoptosis through T2R14 and the mitochondrial calcium uniporter

Head and neck squamous cell carcinomas (HNSCCs) arise in the mucosal lining of the upper aerodigestive tract. HNSCCs have high mortality rates and current treatments can be associated with severe morbidities. It is vital to discover effective, minimally invasive therapies that improve survival and quality of life. We previously discovered that bitter taste receptor 14 (T2R14), a GPCR, kills HNSCC cells when activated by bitter agonists. We are now investigating endogenous bitter ligands that exist in HNSCC tumor microenvironment (TME). The TME includes cells, signaling molecules, and microbes that can greatly influence treatment responses and overall prognosis in HNSCC. Pseudomonas aeruginosa is a gram-negative bacterium that colonizes/infects HNSCC patients. 3-oxo-C12SHL is a quorum-sensing N-acyl homoserine lactone (AHL) secreted by P. aeruginosa which is also a bitter compound. 3-oxo-C12HSL induces apoptosis but this has never been linked to T2R activation. We hypothesized that 3-oxo-C12HSL induces apoptosis in HNSCC via T2R14. We show that 3-oxo-C12HSL activates intracellular Ca2+ responses in HNSCC cells. This is inhibited with T2R14 antagonization. 3-oxo-C12HSL may activate additional Ca2+ channels as the Ca2+ dynamics are independent from store-operated calcium entry (SOCE). 3-oxo-C12HSL inhibits cell viability, depolarizes mitochondria, and produces ROS. This induces apoptosis in HNSCC cells. In a comparative screen of quorum-sensing AHLs, 3-oxo-C12HSL was the only AHL that elicited both a Ca2+ response and reduced cell viability. These results suggest that P. aeruginosa may play a significant role in modulating an anti-tumor TME through 3-oxo-C12HSL. Moreover, 3-oxo-C12HSL could be a novel, higher-affinity bitter therapeutic for HNSCC. Further research is warranted to elucidate the mechanisms of other endogenous T2R agonists present in the TME.

physiology↗

bioRxiv2024

Human Satellite 3 DNA encodes megabase-scale transcription factor binding platforms

Eukaryotic genomes frequently contain large arrays of tandem repeats, called satellite DNA. While some satellite DNAs participate in centromere function, others do not. For example, Human Satellite 3 (HSat3) forms the largest satellite DNA arrays in the human genome, but these multi-megabase regions were almost fully excluded from genome assemblies until recently, and their potential functions remain understudied and largely unknown. To address this, we performed a systematic screen for HSat3 binding proteins. Our work revealed that HSat3 contains millions of copies of transcription factor (TF) motifs bound by over a dozen TFs from various signaling pathways, including the growth-regulating transcription effector family TEAD1-4 from the Hippo pathway. Imaging experiments show that TEAD recruits the co-activator YAP to HSat3 regions in a cell-state specific manner. Using synthetic reporter assays, targeted repression of HSat3, inducible degradation of YAP, and super-resolution microscopy, we show that HSat3 arrays can localize YAP/TEAD inside the nucleolus, enhancing RNA Polymerase I activity. Beyond discovering a direct relationship between the Hippo pathway and ribosomal DNA regulation, this work demonstrates that satellite DNA can encode multiple transcription factor binding motifs, defining an important functional role for these enormous genomic elements.

cell biology↗

bioRxiv2024

Bitter Taste Receptor Agonists Induce Apoptosis in Papillary Thyroid Cancer

BackgroundPapillary thyroid carcinoma (PTC) is the most common thyroid malignancy, with a 20% recurrence rate. Bitter taste receptors (T2Rs) and their genes (TAS2Rs) may regulate survival in solid tumors. This study examined T2R expression and function in PTC cells. MethodsThree PTC cell lines (MDA-T32, MDA-T68, MDA-T85) were analyzed for expression using RT-qPCR and immunofluorescence. Live cell imaging measured calcium responses to six bitter agonists. Viability and apoptosis effects were assessed using crystal violet and caspase 3/7 activation assays. Genome analysis of survival was conducted. ResultsTAS2R14 was consistently highly expressed in all cell lines. Five bitter agonists produced significant calcium responses across all cell lines. All bitter agonists significantly decreased viability and induced apoptosis. Higher TAS2R14 expression correlated with better progression-free survival in patients (p<0.05). ConclusionsT2R activation by bitter agonists induces apoptosis and higher TAS2R expression is associated with survival, suggesting potential therapeutic relevance in thyroid cancer management.

cancer biology↗

bioRxiv2024

Tumor cell-based liquid biopsy using high-throughput microfluidic enrichment of entire leukapheresis product

Circulating Tumor Cells (CTCs), interrogated by sampling blood from patients with cancer, contain multiple analytes, including intact RNA, high molecular weight DNA, proteins, and metabolic markers. However, the clinical utility of tumor cell-based liquid biopsy has been limited since CTCs are very rare, and current technologies cannot process the blood volumes required to isolate a sufficient number of tumor cells for in-depth assays. We previously described a high-throughput microfluidic prototype utilizing high-flow channels and amplification of cell sorting forces through magnetic lenses. Here, we apply this technology to analyze patient-derived leukapheresis products, interrogating a mean blood volume of 5.83 liters from patients with metastatic cancer, with a median of 2,799 CTCs purified per patient. Isolation of many CTCs from individual patients enables characterization of their morphological and molecular heterogeneity, including cell and nuclear size and RNA expression. It also allows robust detection of gene copy number variation, a definitive cancer marker with potential diagnostic applications. High-volume microfluidic enrichment of CTCs constitutes a new dimension in liquid biopsies.

bioengineering↗

bioRxiv2023

Macrophage-targeted lipid nanoparticle delivery of microRNA-146a to mitigate hemorrhagic shock-induced acute respiratory distress syndrome

The pro-inflammatory response of alveolar macrophages to injurious physical forces during mechanical ventilation is regulated by the anti-inflammatory microRNA, miR-146a. Increasing miR-146a expression to supraphysiologic levels using untargeted lipid nanoparticles reduces ventilator-induced lung injury, but requires a high initial dose of miR-146a making it less clinically applicable. In this study, we developed mannosylated lipid nanoparticles that can effectively mitigate lung injury at the initiation of mechanical ventilation with lower doses of miR-146a. We used a physiologically relevant humanized in vitro co-culture system to evaluate the cell-specific targeting efficiency of the mannosylated lipid nanoparticle. We discovered that mannosylated lipid nanoparticles preferentially deliver miR-146a to alveolar macrophages and reduce force-induced inflammation in vitro. Our in vivo study using a clinically relevant mouse model of hemorrhagic shock-induced acute respiratory distress syndrome demonstrated that delivery of a low dose miR-146a (0.1 nmol) using mannosylated lipid nanoparticles dramatically increases miR-146a in mouse alveolar macrophages and decreases lung inflammation. These data suggest that mannosylated lipid nanoparticles may have therapeutic potential to mitigate lung injury during mechanical ventilation.

pharmacology and toxicology↗

bioRxiv2022

Savory Signaling: T1R umami receptor modulates endoplasmic reticulum calcium store content and release dynamics in airway epithelial cells

T1Rs are expressed in solitary chemosensory cells of the upper airway where they detect apical glucose levels and repress bitter taste receptor Ca2+ signaling pathways. Microbial growth leads to a decrease in apical glucose levels. T1Rs detect this change and liberate bitter taste receptor signaling, initiating an innate immune response to both kill and expel pathogens through releasing antimicrobial peptides and increasing nitric oxide production and ciliary beat frequency. However, chronic inflammation due to disease, smoking, or viral infections causes a remodeling of the airway epithelial. The resulting squamous metaplasia causes a loss of multi-ciliated cells and solitary chemosensory cells, replaced by basal epithelial cells. To understand how T1R function is altered during disease, we used basal epithelial cells as a model to study the function of T1R3 on Ca2+ signaling dynamics. We found that both T1R1 and T1R3 detect amino acids and signal via cAMP, increasing the responsiveness of the cells to Ca2+ signaling stimuli. Either knocking down T1R1/3 or treating wild-type cells with MEM amino acids caused a reduction in ER Ca2+ content through a non-cAMP signaled pathway. Treatment with amino acids led to a reduction in downstream denatonium-induced Ca2+-signaled caspase activity. Thus, amino acids may be used to reduce unwanted apoptosis signaling in treatments containing bitter compounds.

physiology↗

bioRxiv2022

Lidocaine Induces Apoptosis in Head and Neck Squamous Cell Carcinoma Cells Through Activation of Bitter Taste Receptor T2R14

Head and neck squamous cell carcinomas (HNSCCs) have high mortality and significant treatment-related morbidity. It is vital to discover effective, minimally invasive therapies that improve survival and quality of life. Bitter taste receptors (T2Rs) are expressed in HNSCCs and their activation can induce apoptosis. Lidocaine is a local anesthetic used in various clinical applications which can also activate bitter taste receptor 14 (T2R14). Lidocaine may have some anti-tumor effects in other cancers, but the mechanism has been mysterious. Here, we found that lidocaine causes intracellular Ca2+ mobilization through activation of T2R14 in HSNCC cells. T2R14 activation with lidocaine depolarizes the mitochondrial membrane, inhibits cell proliferation, and induces apoptosis. Concomitant mitochondrial Ca2+ influx, ROS production causes T2R14-dependent accumulation of poly-ubiquinated proteins, suggesting inhibition of the proteasome as a novel component of T2R14-induced apoptosis. Lidocaine may have therapeutic potential in HNSCC as a topical gel or intratumor injection, warranting future clinical studies. HIGHLIGHTSO_LILidocaine activates bitter taste receptor 14 (T2R14) to increase intracellular Ca2+ and decrease cAMP in head and neck squamous cell carcinoma (HSNCC) cells C_LIO_LILidocaine decreases cell viability and cell proliferation, depolarizes the mitochondrial membrane, and causes production of reactive oxygen species (ROS) C_LIO_LIT2R14 activation with lidocaine induces apoptosis and inhibits the ubiquitin proteasome system (UPS) C_LIO_LILung squamous cell carcinoma (SCC) cells and HNSCC tumor spheroids undergo apoptosis or structural disbandment, respectively, with lidocaine C_LI

cancer biology↗

bioRxiv2022

Akt activator SC79 stimulates antibacterial nitric oxide production from human nasal epithelial cells and increases macrophage phagocytosis in vitro

BackgroundThe role of the Akt serine/threonine kinase family in airway innate immunity is relatively unstudied compared with other pathways. Akt can phosphorylate and activate the endothelial nitric oxide synthase (eNOS) isoform expressed in airway epithelial ciliated cells. NO production by nasal epithelial cells often has antibacterial and antiviral effects. Increasing nasal epithelial NO production may be a useful anti-pathogen strategy for respiratory infections in diseases like chronic rhinosinusitis. We hypothesized that a small molecule Akt activator, SC79, might induce nasal epithelial cell NO production with bactericidal effects. MethodsWe tested the antibacterial-stimulatory effects of SC79 in primary nasal epithelial cells isolated from residual surgical material and grown at air-liquid interface. Because macrophages also use NO signaling to enhance phagocytosis, we also tested effects of SC79 in human macrophages differentiated from monocytes obtained from healthy apheresis donors. ResultsLive cell imaging of an NO-sensitive fluorescent dye revealed that SC79 induced dose-dependent NO production. Pharmacology and genetic knockdown revealed that this NO production is dependent on eNOS and Akt. The NO released into the airway surface liquid was sufficient to kill both lab and clinical strains of P. aeruginosa in a co-culture bacterial killing assay. SC79 enhanced bacterial phagocytosis in a NO-dependent and Akt-dependent manner. No overt toxicity (LDH release) or inflammatory effects (IL8 transcription) were observed in nasal cells or macrophages over 24 hrs. ConclusionsTogether, these data suggest that multiple innate immune pathways might be stimulated by SC79 delivered via topical nasal rinse or spray. Activating Akt using SC79 or another compound might have beneficial antipathogen effects in respiratory infections.

physiology↗