Sinupret Activates CFTR and TMEM16A-Dependent Transepithelial Chloride Transport and Improves Indicators of Mucociliary Clearance

Abstract

IntroductionWe have previously demonstrated that Sinupret, an established treatment prescribed widely in Europe for respiratory ailments including rhinosinusitis, promotes transepithelial chloride (Cl−) secretion in vitro and in vivo. The present study was designed to evaluate other indicators of mucociliary clearance (MCC) including ciliary beat frequency (CBF) and airway surface liquid (ASL) depth, but also investigate the mechanisms that underlie activity of this bioflavonoid.MethodsPrimary murine nasal septal epithelial (MNSE) [wild type (WT) and transgenic CFTR−/−], human sinonasal epithelial (HSNE), WT CFTR-expressing CFBE and TMEM16A-expressing HEK cultures were utilized for the present experiments. CBF and ASL depth measurements were performed. Mechanisms underlying transepithelial Cl− transport were determined using pharmacologic manipulation in Ussing chambers, Fura-2 intracellular calcium [Ca2+]i imaging, cAMP signaling, regulatory domain (R-D) phosphorylation of CFTR, and excised inside out and whole cell patch clamp analysis.ResultsSinupret-mediated Cl− secretion [ΔISC(µA/cm2)] was pronounced in WT MNSE (20.7+/−0.9 vs. 5.6+/−0.9(control), p<0.05), CFTR−/− MNSE (10.1+/−1.0 vs. 0.9+/−0.3(control), p<0.05) and HSNE (20.7+/−0.3 vs. 6.4+/−0.9(control), p<0.05). The formulation activated Ca2+ signaling and TMEM16A channels, but also increased CFTR channel open probability (Po) without stimulating PKA-dependent pathways responsible for phosphorylation of the CFTR R-domain and resultant Cl− secretion. Sinupret also enhanced CBF and ASL depth.ConclusionSinupret stimulates CBF, promotes transepithelial Cl− secretion, and increases ASL depth in a manner likely to enhance MCC. Our findings suggest that direct stimulation of CFTR, together with activation of Ca2+-dependent TMEM16A secretion account for the majority of anion transport attributable to Sinupret. These studies provide further rationale for using robust Cl− secretagogue based therapies as an emerging treatment modality for common respiratory diseases of MCC including acute and chronic bronchitis and CRS.

Hyaluronan mediates airway hyperresponsiveness in oxidative lung injury

“…During exposure, the medium was changed as described above without inhibitors. Measurements of TMEM16A Cl Ϫ activity in HASM cells: current-voltage (I-V) relationships of Cl Ϫ channels of air or Cl2-exposed HASM cells were recorded in the whole cell mode of the patch-clamp technique as described recently (79). During the experiments, cells were perfused at a rate of 1 ml/min with an external solution of the following ionic composition (in mM): 145 CsCl, 2 MgCl 2, 2 CaCl2, 5.5 glucose, 10 HEPES, pH 7.4 (1 N CsOH).…”

Sinupret® as add-on therapy to saline irrigation for children with acute Post-Viral Rhinosinusitis

“…There were also parallel reductions in the expression of the enzyme cyclooxygenase-2, which forms pro-inflammatory prostaglandin E 2 . Zhang et al [7] showed that Sinupret promotes transepithelial chloride transport, and enhances ciliary beat frequency and airway surface liquid depth. Taken together, these activities would tend to enhance mucus clearance.…”

“…One of these preparations is the complex herbal medicine Sinupret which is based on gentian, evening primrose, elder, verbena and sorrel. This herbal medicine has been shown to enhance ciliary activity in vitro [7] and to have anti-inflammatory activity in animal experiments [8]. It has a wide spectrum of pharmacological properties, including secretolytic, secretomotoric, antiviral, anti-inflammatory, and immunomodulatory effects.…”

Sinupret® oral drops protect against respiratory epithelium atrophy in experimental acute rhinitis

“…Mucosal thickening has been described after experimental acute sinusitis (bacterial Staphylococcus aureus induction) in an animal model (rabbits) [15]. However, potential therapeutic effects of Sinupret on mucociliary clearance via the recently described mechanisms of hydration of airway surface liquid and stimulation of ciliary beat frequency [10,12] were not assessed in our model which focused on histological alterations. It can therefore be concluded that the herbal medicinal product Sinupret® partially prevents atrophy of the olfactory epithelium present in the course of acute experimental rhinitis in rats.…”

“…The herbal medicinal product Sinupret®, composed of Gentianae radix, Primulae flos cum calycibus, Sambuci flos, Rumicis herba and Verbenae herba, is frequently used for the treatment of acute or chronic rhinosinusitis [6,7] due to its pleiotropic effects directed against viral replication [8], bacterial infection, and inflammation [9]. In addition, its beneficial impact on mucociliary clearance was demonstrated in vivo in mice and in in vitro experiments using respiratory epithelial cells [10][11][12].…”