Sex-specific IL-6-associated signaling activation in ozone-induced lung inflammation

Abstract

BackgroundAcute ozone (O3) exposure has known deleterious effects on the respiratory system and has been linked with respiratory disease and infection. Inflammatory lung disease induced by air pollution has demonstrated greater severity and poorer prognosis in women vs. men. Both severe damage to the bronchial-alveolar epithelium and malfunctioning of bronchial-blood barrier have been largely attributed to the pathobiology of O3-induced inflammatory response, but the associated mechanisms in the male and female lung remain unknown.MethodsHere, we investigated sex-based differential regulation of lung interleukin-6 (IL-6) and its downstream signaling pathways JAK2/STAT3 and AKT1/NF-κB in response to O3 exposure in a mouse model. We exposed male and female mice (in different stages of the estrous cycle) to 2 ppm of O3 or filtered air (FA) for 3 h, and we harvested lung tissue for protein expression analysis by Western blot.ResultsWe found significant up-regulation of IL-6 and IL-6R in females and IL-6 in males in response to O3 vs. FA. Ozone exposure induced a significant increase in STAT3-Y705 phosphorylation in both females and males. Males exposed to O3 had decreased levels of JAK2, but increased JAK2 (Y1007+Y1008) phosphorylation, while females exposed to O3 showed significant up-regulation of both proteins. Both NF-κB (p105/p50) and AKT1 protein levels were significantly increased only in females exposed to O3. In addition, females exposed to O3 during proestrus displayed increased expression of selected genes when compared to females exposed to O3 in other estrous cycle stages.ConclusionsTogether, our observations indicate a sex-based and estrous cycle-dependent differential lung inflammatory response to O3 and involvement of two converging JAK2/STAT3 and AKT1/NF-κB pathways. To our knowledge, this is the first study specifically addressing the impact of the estrous cycle in O3-associated lung inflammatory pathways.Electronic supplementary materialThe online version of this article (doi:10.1186/s13293-016-0069-7) contains supplementary material, which is available to authorized users.

Transcriptional profiling of the murine airway response to acute ozone exposure

“…This approach would also address the challenge of interpreting whether gene expression in isolated airways of O3-exposed mice is primarily due to altered transcriptional activity or a result of changes in cell composition. We also opted to use only female mice, and sex is known to have an impact on gene expression responses in many contexts, including after O3 exposure (CABELLO et al 2015;MISHRA et al 2016;FUENTES et al 2018). Thus, additional studies will be required to determine the impact of sex on transcriptional responses in the airway epithelium and macrophages.…”

Modulation of the lung inflammatory response to ozone by the estrous cycle

“…Estrous cycle stages were assessed daily for a minimum of 2 weeks prior to exposure experiments. As described by us in the past, cycle stages were determined by the amount of nucleated epithelial cells, leukocytes, and cornified cells in vaginal smears following traditional protocols (Caligioni 2009;Mishra et al 2016;Fuentes and Silveyra 2019). In addition, stages were confirmed by serum determinations of estradiol, LH, and progesterone via ELISA (cats.…”

“…Furthermore, we reported differences in signaling cascades activated in female mice exposed to ozone in different estrous cycle stages (Mishra et al. ). Based on these data, we hypothesized that the stage of the estrous cycle, and more specifically the circulating levels of female hormones in each cycle phase can influence the inflammatory response to ozone.…”

Role of Estrogen Receptors α and β in a Murine Model of Asthma: Exacerbated Airway Hyperresponsiveness and Remodeling in ERβ Knockout Mice

“…In addition to genetic and environmental factors, sex/gender difference plays a pivotal role in the pathophysiology of asthma (Clough, 1993;Weiss and Gold, 1995;de Marco et al, 2000;Caracta, 2003;Carey et al, 2007b;Card and Zeldin, 2009;Woods et al, 2010;Townsend et al, 2012a;Cabello et al, 2015;Mishra et al, 2016;Fuentes and Silveyra, 2019b;Kalidhindi et al, 2019b). Incidence of asthma is more common in pre-pubescent boys and adult women and the severity of asthma is increased during pregnancy (de Marco et al, 2000;Caracta, 2003;Carey et al, 2007b;Bonds and Midoro-Horiuti, 2013).…”