Citations

Mechanical stretch associated with respiratory support can impair airway development and function in neonates, but the mechanisms are not fully understood. Using developing human airway smooth muscle cells exposed to cyclic forces with static stretch to mimic continuous positive airway pressure, we found that stretch dysregulates long-term cell proliferation and inflammatory cytokine production, and mechanosensitive Piezo ion channels may play a role in the proliferation response.

Tandem exposure to cannabinoids and nicotine during pregnancy poses significant risks to fetal development and health including low birth weight, preterm birth, and perinatal death. However, the effect of co-exposure with the most prominent cannabinoids found in Cannabis sativa (Trans-Δ-9- tetrahydrocannabinol (THC) and cannabidiol (CBD)) alongside nicotine on fetal lung development is not well understood. This study aims to investigate the combinatorial impact of CBD, THC, and nicotine, on human lung development through investigating cellular senescence and the potential role of senolytics in alleviating these effects. Human fetal lung explants from 10 to 16 weeks gestation were cultured on air-liquid interface and treated with various concentrations of nicotine (1µM), CBD, and THC (5µM, or 2.5µM each when used in combination), for 72 hours. To assess the effect of senolytics, the explants were also treated for 48 hours with a combination of CBD, THC, and nicotine. Subsequently, senolytics, Dasatinib (D, 250nM) and Quercetin (Q, 375nM), were added or not for an additional 24 hours. After the 72-hour treatment, explants were collected and either fixed for immunofluorescence staining (IF) analyses or used for RNA extraction and quantitative reverse transcription PCR (qRT-PCR). Additionally, the supernatants were used to evaluate the expression of the senescence-associated secretory phenotype (SASP), conducted by Eve Technologies Corporation-Canada. This study used Luminex xMAP technology for multiplexed quantification of 96 Human cytokines, chemokines, and growth factors. Our results demonstrated that co-exposure to CBD, THC, and nicotine increases the expression of the senescence markers CDKN1A (0.1163±0.02384, p=0.0094, n=8) and CDKN2A (0.005793±0.002157, p=0.0516, n=8) encoding P21 and P16 respectively. Moreover, the IF staining showed increased expression of the DNA damage marker γH2A.X following treatment with CBD+THC+nicotine (7.375±2.154% vs 2.245±0.8329%, p=0.0604, n=6). Furthermore, the lung explants treated with cannabinoids and nicotine released cytokines and chemokines involved in immune responses and inflammation among others IL-6, IL-8, M-CSF, MCP-3, MIP-1β, TNFα, MIP-3β, and TSLP (p<0.05). The addition of D+Q reduced SASP secretion and showed a decreasing trend in expression of the senescence genes CDKN1A and CDKN2A compared to the triple treatment. Taken together, our results showed that the combinatorial exposure to CBD, THC, and nicotine increases senescence, DNA damage, and the senescence-associated secretory phenotypes (SASP) secretion. The use of senolytics (D+Q) may prove to be a promising therapeutic option, alleviating several of the negative effects induced by the different substances. RO1HL171915-01A1 RO!HL155104 RO1HL158532-03 ROIHL160570 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Background and PurposeThe aryl hydrocarbon receptor (AhR) is a ligand‐activated transcription factor that maintains cellular homeostasis. AhR in airway fibroblasts, epithelial and immune cells inhibit inflammatory responses. Nevertheless, its expression and role in airway smooth muscle (ASM), an airway structural cell indispensable in asthma pathophysiology, are obscure. This study uncovers AhR expression, underlying mechanisms, and activity in ASM during inflammation and asthma.Experimental ApproachCultured primary human nonasthmatic and asthmatic ASM cells were treated with TNFα/IL‐13, with/without pharmacological inhibitors targeting PI3K, p38MAPK, JNK, NFkB, and AP1. AhR expression was analysed using RNA‐sequencing, confocal microscopy, qPCR, and immunoblotting. AP1 specific role was confirmed using c‐JUN (AP1) siRNA and ChIP‐qPCR. AhR activity was determined by Nano luciferase in AhR agonist‐treated cells.Key ResultsWe found ubiquitous expression of AhR in ASM with up‐regulation in asthmatic ASM. TNFα increased AhR expression, whereas IL‐13 did not. Furthermore, p38 and JNK inhibition significantly reduced AhR expression with TNFα exposure, whereas PI3K inhibition had no effect. AP1 inhibition and c‐JUN knockdown significantly down‐regulated AhR expression, whereas NFkB inhibition showed no effect. TNFα promoted c‐JUN binding to AhR promoter and increased AhR mRNA expression. Additionally, AhR agonists significantly increased the xenobiotic response element (XRE) activity, CYP1B1, and AhR nuclear expression. TNFα exposure reduced XRE activity and AhR nuclear expression.Conclusion and ImplicationsOur findings suggest inflammation and asthma transcriptionally up‐regulates AhR through the p38/JNK‐AP1 pathway in ASM, identifying a potential therapeutic target for modulating AhR and its downstream effects in asthma.

Introduction: Throughout the lifetime of an asthmatic, the lung undergoes changes in the composition of its extracellular matrix (ECM) and becomes more fibrotic, a characteristic feature of airway remodeling. Due to this, lung functionality decreases as the lung becomes less elastic and airway resistance increases. The ECM proteins constantly network with their respective mechanosensory receptors and regulatory proteins on the cell membrane. These signaling interactions allow for continuous interactions and feedback between the ECM and airway smooth muscle cells (ASM). ASM cells are one of the major structural cells that regular airway remodeling and are the primary target for treating asthma. In this study, we investigated the specific alterations that occur in the ECM of ASM cells treated with TGF-β1. Methods: Human primary airway smooth muscle (ASM) cells were grown to confluency in DMEM/F-12 with 10% FBS and 1% AbAm in standard conditions. Cells were serum deprived for 48 hours prior to experiments. Cells were treated with TGF-β1 (2 ng/mL) in serum free media. Cells were harvested after 48 hours and 200 µg of protein lysate was prepared. Data-independent acquisition (DIA) mass spectrometry was performed at IDeA National Resource for Quantitative Proteomics. Fold changes for ECM class proteins were collected from DIA results. Pathway analysis was then done using Qiagen ingenuity pathway analysis. Furthermore, expression patterns of select proteins were confirmed via western blotting. Results: The effects of TGF-β1 on specific types of collagens, integrins, laminins, and additional ECM proteins were analyzed. Western blotting confirmed similar changes in expression as measured by DIA. TGF-β1 exposure upregulated LAMA4, LAMB2, and LAMC1 which is likely to increase the prevalence of Laminins 221 and 421. TGF-β1 augmented integrin signaling by upregulating ITGA7, ITGA11, ITGA1, ITGB1 and downregulating ITGA2 and ITGB8. TGF-β1 increased expression of TSP1, TSP2, TSP3, TNS-C, FB, Elastin and Versican while downregulating TNS-X. Several interactions between ECM proteins and their sensors and receptors were highlighted for their enrichment. Conclusion: The DIA analysis shows an upregulation of proteins involved in airway remodeling by TGF-β1 in ASM cells. These findings substantiate our previous results as well as provide insights into a more targeted approach in studying ECM-Cell interactions. NIH R01HL171245 (Venkatachalem), R01HL146705 (Venkatachalem), R01HL142061 (Pabelick, Prakash). and IDeA National Resource for Quantitative Proteomics (R24GM137786). This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Rationale: Asthma is a chronic inflammatory disease of conducting airways characterized by airway hyperresponsiveness and remodeling. Airway smooth muscle (ASM) is a major structural cell in the airway that contributes to airway hyperresponsiveness and remodeling. Mitochondrial dynamics is a fission/fusion process crucial for optimal function and signal transduction. Inflammation alters the mitochondrial dynamics in ASM, thereby disrupt mitochondrial function and contributes to asthma pathophysiology. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that regulates cellular homeostasis. Recently, we found upregulation of AhR in response to inflammation and asthma in ASM. Additionally, AhR activation inhibited inflammation-induced ASM proliferation and remodeling. However, the role of AhR in regulating mitochondrial dynamics in ASM during inflammation and asthma is obscure. Objective: The aim of this work is to unveil the role of AhR in regulating mitochondrial structure and function in human ASM during inflammation and asthma. Methods: Primary non-asthmatic and asthmatic human ASM cells isolated from surgical lung sections were cultured in DMEM-F12 medium supplemented with 10% FBS and 1% AbAm. Cells were serum deprived, treated with AhR agonist 6-Formylindolo[3,2-b]carbazole (FICZ: 10 nM) and antagonist CH223191 (10 μM), with/or without TNFα (20 ng/mL). Mitochondrial bioenergetics was determined by Seahorse XFp analyzer. Mitochondrial morphology was visualized using mitotracker dye. Expressions of fission and fusion mRNA and protein were determined by qPCR and immunoblotting. Additionally, AhR role in fusion and fission was confirmed in shRNA mediated AhR knockdown and AhR overexpressed ASM cells. Results: AhR activation by FICZ alleviated TNFα-induced disrupted mitochondrial bioenergetics in non-asthmatic ASM cells as well as in asthmatic ASM. Furthermore, TNFα-induced increased mitochondrial fission and reduced fusion was restored by AhR activation in both asthmatic and non-asthmatic ASM. AhR inhibition by CH223191 and knockdown promoted mitochondrial fission and blunted fusion in non-asthmatic ASM cells. Interestingly, AhR overexpression and activation by FICZ restored the mitochondrial dynamics altered by inflammation and asthma in ASM cells. Conclusion: Collectively, AhR activation promotes mitochondrial fusion and abolishes fission induced by inflammation and asthma in human ASM, thereby maintains mitochondrial structure and homeostasis. Therefore, AhR is a potential therapeutic target to mitigate altered mitochondrial dynamics in ASM during inflammation and asthma. Supported by NIH grants R01-HL171245 (Venkatachalem and Britt), R01-HL146705 (Venkatachalem), R01-HL155095 (Britt), R01-HL142061 (Pabelick, Prakash) This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Abstract Rationale: Tandem exposure to cannabinoids and nicotine during pregnancy poses significant risks to fetal development and health including low birth weight, preterm birth, and perinatal death. However, the effect of co-exposure with the most prominent cannabinoids found in Cannabis sativa (Trans-Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD)) alongside nicotine on fetal lung development is not well understood. This study aims to investigate the combinatorial impact of CBD, THC, and nicotine, on human lung development through investigating cellular senescence and the potential role of senolytics in alleviating these effects.Methods: Human fetal lung explants from 10 to 16 weeks gestation were cultured on air-liquid interface and treated with various concentrations of nicotine (1µM), CBD, and THC (5µM, or 2.5µM each when used in combination), for 72 hours. To assess the effect of senolytics, the explants were also treated for 48 hours with a combination of CBD, THC, and nicotine. Subsequently, senolytics, Dasatinib (D, 250nM) and Quercetin (Q, 375nM), were added or not for an additional 24 hours. After the 72-hour treatment, explants were collected and either fixed for immunofluorescence staining (IF) analyses or used for RNA extraction and quantitative reverse transcription PCR (qRT-PCR). Additionally, the supernatants were used to evaluate the expression of the senescence-associated secretory phenotype (SASP), conducted by Eve Technologies Corporation-Canada. This study used Luminex xMAP technology for multiplexed quantification of 96 Human cytokines, chemokines, and growth factors.Results: Our results demonstrated that co-exposure to CBD, THC, and nicotine increases the expression of the senescence markers CDKN1A (0.1163±0.02384, p=0.0094, n=8) and CDKN2A (0.005793±0.002157, p=0.0516, n=8) encoding P21 and P16 respectively. Moreover, the IF staining showed increased expression of the DNA damage marker ɣH2A.X following treatment with CBD+THC+nicotine (7.375±2.154% vs 2.245±0.8329%, p=0.0604, n=6). Furthermore, the lung explants treated with cannabinoids and nicotine released cytokines and chemokines involved in immune responses and inflammation among others IL-6, IL-8, M-CSF, MCP-3, MIP-1β, TNFα, MIP-3β, and TSLP (p&lt;0.05). The addition of D+Q reduced SASP secretion and showed a decreasing trend in expression of the senescence genes CDKN1A and CDKN2A compared to the triple treatment.Conclusion: Taken together, our results showed that the combinatorial exposure to CBD, THC, and nicotine increases senescence, DNA damage, and the senescence-associated secretory phenotypes (SASP) secretion. The use of senolytics (D+Q) may prove to be a promising therapeutic option, alleviating several of the negative effects induced by the different substances.

Abstract Rationale: Asthma involves airway inflammation, hyperresponsiveness (AHR), and remodeling (cell proliferation and fibrosis), with both aspects not fully alleviated by current therapies. GPCR-based drugs represent a major aspect of current asthma therapy. Asthmatic airways express several orphan receptors with unknown physiological roles, highlighting a potentially novel and significant area for therapeutic exploration. Herein, we focus on orphan retinoic acid (RA)-induced Class C GPCR members GPRC5A (RAIG1; 5A) and GPRC5B (RAIG2; 5B). We leveraged recently identified 5A agonists to test the hypothesis that these GPCRs have alleviating effects in airways. Methods: Primary human airway smooth muscle cells (ASM) originating from non-asthmatic (NA) and asthmatic (Asth) individuals were obtained post-surgery from lung tissues after approval by the Mayo Clinic Institutional Review Board. PRESTO-Tango assay was used to determine 5A and 5B activity. cADDis assay was used to assess cAMP levels. Fluorescence imaging was used to determine calcium regulation. Recently identified 5A agonists [tryptamine, 7 fluoro-tryptamine (7FT), L-tryptophan, N-methyltryptamine, and indole-3-acetic acid] were used in assays, along with RA and 5A vs. 5B siRNAs. Results: PRESTO-Tango assay showed that tryptamine (10/100 µM) and 7FT (1/10/100 µM) increased 5A activity while high concentrations of 7FT (100 µM) increased 5B activity as well. cADDis assay showed 100 µM tryptamine increased cAMP more than 1/10 µM tryptamine and that 10 µM 7FT increased cAMP more than 1/100 µM 7FT in NA ASM.Calcium imaging showed that 5A agonist blunts responses to histamine, especially in Asth ASM. Calcium responses were higher in Asth ASM and 5A siRNA-treated ASM while 5B siRNA had an alleviating effect. Conclusions: Class C GPCRs 5A and 5B interestingly have opposing effects in human ASM towards blunting calcium responses to bronchoconstrictor agonists in the context of asthma. Thus, 5A agonists and 5B antagonists may represent novel GPCR-based approaches in airway diseases.

Abstract Rationale: Moderate hyperoxia (&lt;60% O2) in premature infants promotes bronchial airway hyperresponsiveness (AHR) and impaired bronchodilation involving airway smooth muscle (ASM). Understanding mechanisms by which hyperoxia initiates long-term bronchial airway changes in prematurity is critical for novel therapies for wheezing disorders and asthma in children. Underdeveloped lungs in prematurity have immature antioxidant systems, which may be due to disrupted dynamics that promote susceptibility to oxidative stress from O2. Cytoplasmic and mitochondrial calcium signaling mechanisms and O2 metabolism are pathways highly relevant to ASM and airway disease. We propose that the novel gasotransmitter hydrogen sulfide (H2S) attenuates effects of O2 in developing ASM and hypothesize that hyperoxia in prematurity promotes cellular and mitochondrial calcium signaling dysfunction, effects which are counteracted by H2S.Methods: Human fetal (fASM) cells isolated from tracheobronchial samples of de-identified 18-22 week fetuses following fetal demise (Mayo IRB approved as exempt) were exposed to 21% vs 40% O2. fASM were treated 24-72 hours with H2S donor GYY4137, mitochondrial-specific H2S donor AP39, cystathione-β-synthase (CBS) stabilizer AdoMet, cAMP inhibitors SQ22536 or KT5720, or vehicle control (DMSO). CBS shRNA lentiviral particles were used to generate stable knockdown cell lines. Protein markers were measured by Western blot. Intracellular calcium ([Ca2+]i) was measured using 5μM Fura-2/AM and mitochondrial calcium ([Ca2+]m) with 1μM Rhod-2 AM using fluorescence microscopy. Results: CBS expression was lower in fASM exposed to 40% O2 compared to 21% O2. Lentivirus induced CBS KD was exacerbated by 40% O2. Hyperoxia increased [Ca2+]i and [Ca2+]m response to histamine (10μM) in vehicle and Scr controls compared to normoxia. CBS KD increased [Ca2+]i and [Ca2+]m responses to histamine compared to Scr fASM in 21% O2. CBS KD fASM exposed to hyperoxia showed increased [Ca2+]i and [Ca2+]m responses to histamine, but the effect was not amplified by CBS KD. [Ca2+]i and [Ca2+]m responses to histamine were decreased in normoxia by H2S donors GYY4137 (50μM) and AP39 (100nM) and CBS stabilizer AdoMet (100nM); effects which also blunted hyperoxia induced increases. SQ22536 and KT5720 inhibited effects of AP39 and GYY4137 in hyperoxia. Conclusions:Our findings suggest hyperoxia leads to [Ca2+]i and [Ca2+]m dysfunction in developing airway cells, which can be alleviated through modulation of H2S pathways, offering potential targets for future therapies to blunt hyperoxia effects on bronchoconstriction and bronchodilation. Acknowledgment: Supported by AHA Postdoctoral Fellowship 20POST35210002 (Bartman), NIH R01 HL-056470 (Prakash), and HL-160570 (Pabelick).

Abstract Background: Kisspeptins (Kp) are a group of hypothalamic peptides that aid in regulating pubertal development and sex hormone signaling. In our recent studies, we observed the important role of Kp-10 (Kp peptide) and its receptor KISS1R signaling in regulating the airway smooth muscle (ASM) structure and function. In these studies, we observed significantly reduced expression of KISS1R during asthma pathophysiology suggesting a loss of protective mechanism and exogeneous Kp-10 may be protective in the context of asthma. Studies have shown that specific modifications to the amino acids of Kp peptides can result in increased binding efficiency and receptor activation. Accordingly, we developed three novel Kp peptides, named KpSATs (13A, 13B, and 13C), and tested the potential effects/efficiency on ASM cell remodeling. Methods: The Molecular docking of the KpSAT peptides (13A, 13B and 13C) with the receptor KISS1R were performed using HPEPDOCK. KpSATs were synthesized by GenScript (New Jersey, US) with purity of ≥97%. Primary human ASM cells isolated from surgical lung resections (Mayo Clinic IRB-approved) were cultured in DMEM-F12. Cells were treated with PDGF (2ng/mL) and/or TGF-β (2ng/mL) with/without treatments of KpSATs (13A, 13B, and 13C: 250nM-1µM) and Kp-10 (1µM). ASM cell proliferation was measured using MTT. Extracellular matrix (ECM) deposition (fibronectin and collagen-I/III) studies were performed using In-Cell Western (LiCor-odyssey). The mechanistic signaling pathway (phospho-PKC-δ) were measured using Western blot analysis. Results: In the novel KpSATs, we substituted three amino acids in the endogenous Kp-13 sequence, Y10W and P12T for KpSAT-13A; S6A and P12T for KpSAT-13B; and S6A and Y10W for KpSAT-13C. The peptides dock in the orthosteric ligand binding pocket attained with docking scores ranging from -250 to -280. The MTT assay indicated a reduction in PDGF-induced ASM cell proliferation upon exposure to KpSATs. Notably, we found that KpSAT-13A and KpSAT-13B had significant effects in reducing proliferation at lower concentrations of 500nM compared to 1µM of Kp-10. Furthermore, ECM deposition studies showed a significant reduction of TGF-β1-induced collagen-I/III and fibronectin in ASM cells exposed to KpSAT-13A and 13B. In addition, we observed significant inhibition of PDGF-induced phospho-PKC-δ by KpSAT-13A and 13B. Conclusion: Overall, these findings highlight that modification in amino acid sequence in endogenous Kp-13 sequence significantly increases the potency of synthesized novel KpSATs on ASM cells. In addition, KpSATs showed better inhibitory effects with a lower concentration compared to Kp-10 and could be considered as a promising therapeutic strategy to mitigate asthma.

Abstract Rationale: With an increasing elderly population, understanding mechanisms that contribute to structural and functional changes in aging lung is important in the context of healthy aging and diseases such as asthma and pulmonary fibrosis that disproportionately affect the elderly. Asthma in the elderly (AIE) is a particular challenge, with thickened fibrotic bronchial airways (remodeling) and inflammation compared to non-asthmatic elderly: issues not addressed by current therapies. Factors such as iron regulation that are critical for normal physiology can become dysregulated in disease. Iron overload can catalyze a Fenton reaction that increases ROS which oxidizes lipids and proteins, i.e. iron-mediated lipid peroxidation cell death (ferroptosis).The goal of this study was to determine iron regulation in aging- and AIE-associated in human ASM (hASM), a cell type important in airway contractility and remodeling. Methods: hASM cells and lung tissues from young (&lt;45y), and aged (&gt;65y) male/female patients with/without asthma were used (approved by Mayo IRB #16-009655). Cells were treated with ferroptosis inhibitor deferoxamine (DFO) [100µM], inducer RSL3 [125 nM] or vehicle (DMSO) for 24 hrs. Levels of intracellular iron (Fe2+) were determined using FerroOrange. Cell lysates were examined for iron accumulation and ferroptosis markers (4-HNE, FTH1, TfR1, SLC7A11, and KEAP1), cell proliferation, and ECM production (COL1A1 and FN1), and supernatants analyzed for proinflammatory mediators IL-6 and IL-8. Results: Non-asthmatic and asthmatic elderly hASM cells showed a higher cytosolic Fe2+ and lower end-product of lipid peroxidation (4-HNE), higher level of SLC7A11 and KEAP1 (regulators of redox systems) compared to cells from young individuals. High level of iron storage (FTH1) was observed in asthmatics compared to non-asthmatic elderly, but no difference was observed for iron transporters (TfR1). Furthermore, COL1A1 and FN1 were higher in AIE hASM, compared to young hASM. COL1A1 was higher in aging hASM compared to young. DFO reduced COL1A1 in elderly, but upregulated in AIE. Cell proliferation was inhibited by DFO in aging hASM but not in young and AIE. The ferroptosis inducer RLS3 impaired antioxidant system and increased lipid peroxidation and IL-8 levels. Conclusions: Our findings suggest that iron regulation is impaired in aging and AIE hASM, resulting in iron accumulation which modulates airway remodeling via cell proliferation and ECM production. While ferroptosis per se can be targeted, it will be important to explore modulation of specific iron regulatory pathways in alleviating the impact of aging and asthma.