Kumar, Ashish

This review identifies the menopausal transition as a critical yet underrecognized determinant of asthma heterogeneity in midlife women. It synthesizes evidence that fluctuating sex hormones may shape distinct asthma phenotypes and endotypes, influencing clinical manifestations, disease modifiers, and therapeutic responses. By framing menopause-associated asthma as a biologically distinct, hormone-driven condition, the article highlights key research priorities for precision medicine approaches tailored to women’s respiratory health.

Abstract In asthma, pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNFα) drive excessive mitochondrial fission in ASM cells through activating dynamin-related protein 1 (DRP1). Recently, we demonstrated that aryl hydrocarbon receptor (AhR) is expressed in human ASM and is upregulated during inflammation and asthma. This study explores the role of AhR in regulating mitochondrial fission in human ASM cells under pro-inflammatory and asthmatic conditions. Primary human nonasthmatic and asthmatic ASM cells were treated with 6-formylindolo[3,2-b]carbazole (FICZ: AhR agonist), with or without TNFα. Mitochondrial morphology was assessed using MitoTracker staining. DRP1 expression was evaluated in whole-cell and mitochondrial fractions. Loss- and gain-of-function studies (AhR inhibition, knockdown, and overexpression) were performed. AhR binding on the DRP1 promoter and promoter activity were assessed by ChIP-qPCR and luciferase reporter. The effects of AhR activation on oxygen consumption rate (OCR) were analyzed using seahorse XF-Pro. AhR activation significantly inhibited TNFα- and asthma-induced mitochondrial fission in ASM cells via inhibiting DRP1 in both inactive and active forms. In contrast, AhR inhibition or knockdown aggravated mitochondrial fission, while AhR overexpression failed to prevent TNFα-induced fission without ligand activation. Mechanistically, AhR bound the DRP1 promoter and suppressed its promoter activity, consistent with a genomic mode of action, while failing to alter ERK1/2 phosphorylation. Additionally, AhR activation also reduced TNFα- and asthma-induced increase in OCR. Collectively, this study shows that AhR activation prevents mitochondrial fission by inhibiting DRP1 in ASM during inflammation and highlights AhR as a promising therapeutic target for asthma and other airway diseases associated with mitochondrial dysfunction.

This novel study deciphered the expression and function of protein phosphatase 2Aα (PP2Aα) in airway smooth muscle (ASM) during asthma and/or inflammation. We showed robust expression of PP2Aα in human ASM while its downregulation in asthmatic ASM. Similarly, we demonstrated reduced PP2Aα expression in ASM exposed to proinflammatory cytokines. PP2Aα activation inhibited bronchoconstriction of isolated mouse bronchi. In addition, we unveiled that PP2Aα activation inhibits the intracellular calcium release and myosin light chain phosphorylation in human ASM.

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.