Improved diagnostic yield of symptom association probability involving only cough for gastroesophageal reflux-induced chronic cough.

Background: Use of symptom association probability (SAP) is recommended for identifying gastroesophageal reflux-induced chronic cough (GERC). This study aimed to compare the diagnostic yield of SAPs involving only cough (C-SAP) or total symptoms (T-SAP) for GERC identification. Methods: Patients with both chronic cough and other reflux-related symptoms underwent multichannel intraluminal impedance-pH monitoring (MII-pH) between January 2017 and May 2021. C-SAP and T-SAP were calculated based on the patient-reported symptoms. GERC was definitively diagnosed by the favorable response to anti-reflux therapy. The diagnostic yield of C-SAP in identifying GERC was evaluated by receiver operating characteristic curve analysis and compared with that of T-SAP. Results: MII-pH was performed in 105 patients with chronic cough, and GERC was confirmed in 65 (61.9%), including 27 (41.5%) cases of acid GERC and 38 (58.5%) cases of non-acid GERC. The positive rates of C-SAP and T-SAP were comparable (34.3% vs. 23.8%, P>0.05), but C-SAP exhibited a higher sensitivity (53.85% vs. 33.85%, χ2=8.117, P=0.004) and similar high specificities (97.5% vs. 92.5%, P>0.05) compared with T-SAP for GERC identification. C-SAP was also more sensitive for recognition of acid GERC (51.85% vs. 33.33%, χ2=7.386, P=0.007) and non-acid GERC (65.79% vs. 39.47%, χ2=14.617, P<0.001). More GERC patients with positive C-SAP needed intensified anti-reflux therapy for cough resolution when compared with those with negative C-SAP (82.9% vs. 46.7%, χ2=9.449, P=0.002). Conclusions: C-SAP was superior to T-SAP for the identification of GERC and may improve the diagnostic yield of GERC.

Type II, but not type I, cGMP-dependent protein kinase reverses bFGF-induced proliferation and migration of U251 human glioma cells.

Previous data have shown that the type II cGMP­dependent protein kinase (PKG II) inhibits the EGF­induced MAPK signaling pathway. In order to thoroughly investigate PKG, it is necessary to elucidate the function of another type of PKG, PKG I. The aim of this study was to investigate the possible inhibitory effect of PKG II and PKG I activity on the basic fibroblast growth factor (bFGF)­induced proliferation and migration of U251 human glioma cells and the possible underlying mechanisms. U251 cells were infected with adenoviral constructs encoding cDNA of PKG I (Ad­PKG I) or PKG II (Ad­PKG II) to increase the expression levels of PKG I or PKG II and then treated with 8­Br­cGMP and 8­pCPT­cGMP, respectively, to activate the enzyme. An MTT assay was used to detect the proliferation of the U251 cells. The migration of the U251 cells was analyzed using a Transwell migration assay. Western blot analysis was used to detect the phosphorylation/activation of the fibroblast growth factor receptor (FGFR), MEK and ERK and the nuclear distribution of p-ERK. The results showed that bFGF treatment increased the proliferation and migration of U251 cells, accompanied by increased phosphorylation of FGFR, MEK and ERK. Furthermore, the nuclear distribution of p-ERK increased following bFGF treatment. Increasing the activity of PKG II through infection with Ad-PKG II and stimulation with 8-pCPT-cGMP significantly attenuated the aforementioned effects of the bFGF treatment, while increased PKG I activity did not inhibit the effects of bFGF treatment. These data suggest that increased PKG II activity attenuates bFGF­induced proliferation and migration by inhibiting the MAPK/ERK signaling pathway, whereas PKG I does not.

Endogenous cGMP-dependent protein kinase reverses EGF-induced MAPK/ERK signal transduction through phosphorylation of VASP at Ser239.

In our previous study, we demonstrated that type II cGMP-dependent protein kinase (PKG II) was expressed at lower levels in different human cancer cell lines and that exogenous PKG II inhibited epidermal growth factor (EGF)-induced MAPK/ERK signaling. In order to investigate its functions further in this signaling pathway, it is necessary to elucidate whether endogenous PKG has the same effect or not. This study aimed to investigate the possible inhibitory effect of endogenous PKG activity on EGF-induced MAPK/ERK signal transduction in human lung cancer cells and its mechanism. Human small cell lung carcinoma cells (SCLCs) were treated with the PKG-selective cGMP analog 8-pCPT-cGMP to activate endogenous PKG, EGF and cGMP followed by EGF, respectively. The results showed that increased endogenous PKG activity inhibited the EGF-induced phosphorylation of the epidermal growth factor receptor (EGFR) and the binding between Sos1 and Grb2. In addition, EGF-triggered Ras activation was reversed by increased endogenous PKG activity. While the EGF-induced phosphorylation of MEK and ERK were inhibited by increased endogenous PKG activity, there was a significant increase of phosphorylated vasodilator-stimulated phosphoprotein (p-VASP) at Ser239. Furthermore, we investigated whether endogenous PKG exerted its effects on EGF-induced MAPK/ERK signaling through phosphorylation of VASP at Ser239. Downregulation of the levels of p-VASP Ser239 by point mutation blocked the effects of endogenous PKG on EGF-induced MAPK/ERK signal transduction. The data shown here suggest that endogenous PKG reverses the EGF-induced MAPK/ERK signaling pathway by phosphorylating VASP at Ser239.