(B) Cx43 expression in the bronchial epithelium (white arrows) and in the surrounding pulmonary alveoli (yellow arrows) gradually rose from 8 h after the first challenge in the OVA/OVA group. Results == The OVA-induced mice exhibited typical pathological features of asthma, including airway hyper-responsiveness; strong inflammatory cell infiltration surrounding the bronchia and vessels; many inflammatory cells in the bronchoalveolar lavage fluid (BALF); higher IL-4, IL-5 and IL-13 levels; and high OVA specific IgE levels. Low Cx43 expression was detected in the lungs of control (PBS) mice. A dramatic increase in the Cx43 mRNA and protein levels was found in the asthmatic mice. Cx43 mRNA and protein expression levels increased in a time-dependent manner in asthma mice, and Cx43 was mostly localized in the alveolar and bronchial epithelial layers. Moreover, lung Cx43 protein levels showed a significant positive correlation with inflammatory cell infiltration in the airway and IL-4 Rabbit polyclonal to HSL.hormone sensitive lipase is a lipolytic enzyme of the ‘GDXG’ family.Plays a rate limiting step in triglyceride lipolysis.In adipose tissue and heart, it primarily hydrolyzes stored triglycerides to free fatty acids, while in steroidogenic tissues, it pr and IL-5 levels in the BALF at different time points after challenge. Interestingly, the increase in Cx43 mRNA and protein levels occurred prior to the appearance of the inflammatory cell infiltration. == Conclusion == Our data suggest that there is a strong upregulation of Cx43 mRNA and protein levels in the lungs in asthma. Cx43 levels also exhibited a positive correlation with allergic airway inflammation. Cx43 may represent a target to treat allergic airway diseases in the future. == Introduction == Asthma is a common heterogeneous respiratory disease that has increased over the past 50 years [1]. Asthma is caused by allergen inhalation, leading to airway hyper-responsiveness, inflammation infiltration, mucous production, structural changes in the airway walls and airway obstruction [2]. Recently, a substantial body of evidence suggested the importance of epithelial cells [3, 4] and innate lymphoid cells [5, 6] in initiating and sustaining the allergic cascade. Despite increasing evidence regarding the import role of epithelial cells in airway allergy inflammation, including contribution of activation and survival of mast cells, basophil and eosinophils [7], the underlying molecular mechanisms remain incompletely characterized, especially regarding the cell-cell interactions and the molecules involved. Direct cell-to-cell communication mediated by gap junction channels (GJCs) plays several central roles in cell growth and differentiation, cell cycle regulation and carcinogenesis [810]. GJCs are essential for coordinating tissue homeostasis and regulating inflammatory responses, which directly link the cytoplasm, which allows for conduction of intercellular signals between adjacent cells. This behavior enables the lung, which is composed of many types of cells, to behave as an integrated system [1113]. Connexins from both cells dock to form a GJC and allow the passage of metabolites (i. e., ATP), second messengers and small soluble molecules between the cell interior and Eltrombopag Olamine the interstitial space, thereby coupling the cells both electrically and metabolically [14, 15]. More than twenty types of connexins have been characterized in humans, Eltrombopag Olamine including Cx26, Cx32, Cx37, Cx40, Cx43 and Cx46. Cx43 is one of the most frequently expressed connexins [11, 12]. As an inflammatory mediator and signal conductor, Cx43 plays an important role in the pathogenesis of many lung diseases, including acute lung injury (ALI), cystic fibrosis (CF), pulmonary arterial hypertension (PAH) and cancer [11]. Cx43 expression is increased at the alveolar level in ALI [16] and in the pulmonary arterial wall during PAH [17]. The pro-inflammatory role of Cx43 was also confirmed by lipopolysaccharide (LPS)-mediated inflammation using Cx43+/- mice [18]. Recently, a study showed that OVA challenged mice developed typical asthma, accompanying decrease of connexin37, another family member of connexins [19]. These studies lead us to investigate the importance of Cx43 in asthma-mediated airway abnormality [20]. In the present study, we used a murine ovalbumin (OVA)-induced asthma model to examine the expression and location of Cx43 during allergic disease and the correlation between Cx43 expression and airway allergic inflammation. == Materials and Methods == == Animals Eltrombopag Olamine and experimental protocol == Female BALB/c mice (4- to 6-wk-old) were purchased from the Guangdong Medical Laboratory Animal Center (Guangzhou, China) and acclimatized for 1 week prior to starting the experiments. The animals were maintained under specific pathogen-free conditions and fed by professional technicians in The Animal Center, Sun Yat-sen University. All procedures were approved by the Institutional Animal Care and Use Committee, Sun Yat-sen University (No. IACUC 20110228002). OVAinduced asthma was performed as described in our previous report with a minor modification (Fig 1) [20]. Briefly, the mice were sensitized with an i. p. injection of 40 g/mouse of OVA (grade V, Sigma, St . Louis, MO, USA) and 4 mg of aluminum hydroxide (Thermo Scientific, Rockford, MD, USA) in 100 l of pyrogen-free phosphate-buffered saline (PBS, PH = 7. 3) or equal amounts of PBS on days 1, 7 and 14. Then,.