Kisspeptin Reduces Airway Hyperreactivity and Remodeling in Asthmatic Ovariectomized Mice

Abstract

RationaleEpidemiological data show changes in asthma occurrence with age and sex. After puberty, increased severity in women shows sex‐skewed occurrence of asthma in females vs. males. This implies the importance of female sex‐steroids, particularly estrogen in asthma pathophysiology. Greater asthma in women may represent detrimental mechanisms upstream to or independent of estrogen. Moreover, data from CNS studies show kisspeptin (Kp) signaling is modulated by estrogen. Our recent in vitro studies show Kp via its receptor, KISS1R regulates airway smooth muscle (ASM) cell proliferation. However, the relevance of endogenous estrogen on Kp/KISS1R signaling and their effect on regulating airway hyperresponsiveness (AHR) and remodeling is not yet explored. Accordingly, in this present study, we utilized intact female vs. ovariectomized (OVX) mice to isolate estrogen influence from the Kp effect in regulating AHR and remodeling in a murine model of allergic asthma.MethodsWild Type C57BL/6J intact female and OVX mice were procured from Jackson Laboratory, USA, and challenged intranasally with a mixed‐allergen (MA) for 28 days. On alternate days, animals from the treatment group received intranasal Kp‐10 (1.2mg/kg), vehicle group received PBS alone. On day 29, mice were anesthetized and subjected to SCIREQ flexiVent to measure lung mechanics like airway resistance (Rrs), elastance (Ers), compliance (Crs), tissue damping (G), and tissue‐elasticity (H). Following this, bronchoalveolar lavage (BAL) was performed for differential leukocyte count (DLC) and lung tissues were processed for histology using hematoxylin and eosin (H&E) and trichrome staining. Additionally, laser‐capture microdissection (LCM) assisted qRT‐PCR analysis in ASM cells was performed for genes relevant to airway remodeling.ResultsMA‐challenged intact female and OVX mice showed a significant increase in Rrs, Ers, G, H, and reduced Crs compared to PBS, more pronounced effects were observed in intact females. Kp‐10 treatment significantly reversed the MA‐induced changes with a decrease in Rrs, Ers, G, H, and increased Crs. Interestingly, in OVX mice we observed significant effects of Kp‐10 to improve the lung mechanics compared to intact females. Notably, Kp‐10 alone exposed group did not show any changes in lung mechanics compared to PBS. DLC in BAL showed Kp‐10 treatment significantly reduced MA‐induced inflammatory cell infiltration. Futhermore, histology studies showed Kp‐10 treatment significantly reduced MA‐induced smooth muscle mass and collagen deposition in airways.ConclusionOverall, this study shows the modulatory role of estrogen in regulating kisspeptin signaling, thereby AHR and remodeling. Thus, providing the relevance to higher asthma incidence and severity in women compared to men.