Prakash, Y. S.

Abstract Airway remodeling is a cardinal feature of asthma, associated with increased airway smooth muscle (ASM) cell mass and upregulation of extracellular matrix deposition. Exaggerated ASM cell migration contributes to excessive ASM mass. Previously, we demonstrated the alleviating role of Kp (kisspeptin) receptor (KISS1R) activation by Kp-10 in mitogen (PDGF [platelet-derived growth factor])-induced human ASM cell proliferation in vitro and airway remodeling in vivo in a mouse model of asthma. Here, we examined the mechanisms by which KISS1R activation regulates mitogen-induced ASM cell migration. KISS1R activation using Kp-10 significantly inhibited PDGF-induced ASM cell migration, further confirmed using KISS1R shRNA. Furthermore, KISS1R activation modulated F/G actin dynamics and the expression of promigration proteins like CDC42 (cell division control protein 42) and cofilin. Mechanistically, we observed reduced ASM RhoA-GTPAse with KISS1R activation. The antimigratory effect of KISS1R was abolished by PKA (protein kinase A)-inhibitory peptide. Conversely, KISS1R activation significantly increased cAMP and phosphorylation of CREB (cAMP-response element binding protein) in PDGF-exposed ASM cells. Overall, these results highlight the alleviating properties of Kp-10 in the context of airway remodeling.

Rhythms in lung function and time-of-day-dependent exacerbation in disease symptoms have been noted dating back to the 5th century. Today, we recognize the 24-hour variation in normal lung function and how these fluctuations are associated with the circadian component of lung pathophysiology. Diseases of the airway such as allergic asthma, COPD, pulmonary fibrosis, pneumonia and sepsis, and lung cancer all have documented correlations with circadian rhythm and the peripheral molecular clock. Additionally, chronic exposure to particulate matter and other pollutants can induce alterations in clock genes/proteins, and disruption of the circadian system increases susceptibility to poor outcomes following insult to the airway. Investigations into targets of the molecular clock have shed light on chronotherapeutics that can be used to optimize therapeutic approaches in the clinic or leverage endogenous circadian networks to enhance efficacy of currently available treatments.

Alveolar type I (ATI) epithelial cells perform essential roles in maintaining lung function but have been challenging to study. We explored the signals that promote ATI fate in 3-D organoid cultures generated from either mixed distal human lung cells or purified alveolar type II (ATII) cells. This work fills an important void in our experimental repertoire for studying alveolar epithelial cells and identifies signals that promote human ATII to ATI cell differentiation.

AbstractPulmonary hypertension (PH) associated with chronic kidney disease (CKD) (PH‐CKD) affects approximately 20%–40% of CKD patients and is associated with increased morbidity and mortality. PH and CKD are both pathophysiologically associated with nitric oxide (NO) deficiency. The NO pathway, an important therapeutic domain in pulmonary arterial hypertension (PAH), is an intriguing but unexplored target in PH‐CKD. We sought to improve understanding of the clinical significance of the NO pathway in patients with PH‐CKD by assessing the hemodynamic response to inhaled NO (iNO) during right heart catheterization (RHC). In this retrospective cohort study, patients with diagnosis codes of PH and stage IV/V CKD or end‐stage renal disease and estimated glomerular filtration rate < 60 mL/min/body surface area who underwent RHC and hemodynamic drug study between July 2011 and June 2021 were eligible. Patients with mean pulmonary artery pressure (mPAP) > 20 mmHg and pulmonary vascular resistance (PVR) > 3 Wood units were included. The final cohort included 37 patients (45.9% female, mean age 72.5 ± 9.7 years). A total of 56.7% of the cohort (21/37) had precapillary PH, while 43.2% (16/37) had combined precapillary postcapillary PH (Cpc‐PH). Median survival was 3.1 years after RHC. iNO was associated with a significant decrease in both mPAP and PVR. Hemodynamic changes in mPAP and PVR were similar in precapillary and Cpc‐PH groups. Among a small subset (n = 14) who were subsequently treated with PAH‐targeted therapy, treatment response was mixed and did not reveal significant benefit. Further studies are warranted to better define the potential role of PAH therapy in PH‐CKD.

With continued smoking of tobacco products and expanded use of nicotine delivery devices worldwide, understanding the impact of smoking and vaping on respiratory health remains a major global unmet need. Although multiple studies have shown a strong association between smoking and asthma, there is a relative paucity of mechanistic understanding of how elements in cigarette smoke impact the airway. Recognizing that nicotine is a major component in both smoking and vaping products, it is critical to understand the mechanisms by which nicotine impacts airways and promotes lung diseases such as asthma. There is now increasing evidence that α7 nicotinic acetylcholine receptors (α7nAChRs) are critical players in nicotine effects on airways, but the mechanisms by which α7nAChR influences different airway cell types have not been widely explored. In this review, we highlight and integrate the current state of knowledge regarding nicotine and α7nAChR in the context of asthma and identify potential approaches to alleviate the impact of smoking and vaping on the lungs.

Introduction Asthma is acutely aggravated and chronically worsened by cigarette smoke (CS), as well as secondhand smoke exposure. In this regard, studies show significant differences between women vs. men in their response to the detrimental effects of CS, suggesting that female sex steroids (particularly estrogen) may be involved. Airway smooth muscle (ASM) cell proliferation and airway remodeling is a key feature of asthma and COPD. Surprisingly, there is little information regarding sex steroid effects on cigarette smoke‐induced changes of airway structure and function. In the current study, we hypothesize that estrogen interferes with CSE exposure‐induced proliferation, thereby contributing to airway smooth muscle remodeling. Methods and Results Human ASM tissues (epithelium‐denuded) and isolated ASM cells were from lung samples of patients with known smoking histories undergoing thoracic surgery for non‐infectious, focal pathology. Exposure of human ASM to cigarette smoke extract (CSE, Kentucky research cigarette 1RF4) 1%CSE or 2%CSE for 24h significantly increased ASM proliferation (proliferation assay: Cell Titer Aueous One, and Cyquant). Exposure of physiological concentrations of 17‐β‐estradiol (E 2, 1nM) did not alter ASM proliferation at baseline. Interestingly, E 2 pre‐treatment (1 h prior to CSE exposure) significantly reduced CSE‐induced human ASM proliferation. This was further confirmed by Western blot analysis for proliferative markers PCNA and Cyclin E. In addition, to explore the mechanistic bases of differential effects of E 2 on ASM proliferation under basal and CSE‐exposed conditions, the estrogen receptor profile in ASM tissue was screened in parallel for patients with and without smoking histories. Human ASM tissue from smokers samples showed substantial increased ERα and β expression compared to non‐smokers. Inhibition of ERα and β prevented the effects of estrogen on CSE‐induced increases in proliferation. Conclusions Collectively, estrogen exposure decreased human ASM proliferation induced by CSE. ER expression and signaling is enhanced in CSE induced inflamed ASM, with a potential beneficial role in reducing remodeling with CS exposure. These results will lay the foundation for examining the role of estrogen signaling in pathogenesis of cigarette smoke‐induced airway remodeling and possible sex based therapeutic targets in smoking‐related diseases. Support or Funding Information Supported by Flight Attendants Medical Research Institute (VS) and NIH R01 grant HL123494 (VS)

Local production of growth factors within the airway with autocrine/paracrine effects can promote features of asthma. Here, we show that glial-derived neurotrophic factor (GDNF) is a procontractile and proremodeling factor that contributes to allergen-induced airway hyperreactivity and tissue remodeling in a mouse model of asthma. Blocking GDNF signaling attenuates allergen-induced airway hyperreactivity and remodeling, suggesting a novel approach to alleviating structural and functional changes in the asthmatic airway.

Chronic airway disease is a short- and long-term consequence of premature birth. Understanding effects of O2 exposure during the perinatal period is key to identify targetable mechanisms that initiate and sustain adverse airway changes. Our findings show a beneficial effect of exogenous H2S on developing mouse airway structure and function with notable sex differences. H2S donors alleviate effects of O2 on airway hyperreactivity, contractility, airway smooth muscle thickness, and extracellular matrix deposition.

Asthma is a major healthcare burden, which is further exacerbated by smoking. Recognizing the smoking risk of asthma, understanding the effects of nicotine on asthmatic airways becomes critical. Surprisingly, the mechanisms of nicotine action, even in normal and especially asthmatic airways, are understudied. Accordingly, the goal of this research is to investigate how nicotine influences asthmatic airways in terms of mitochondrial structure and function, via the a7nAChR.