Background: Excessive activation of matrix metalloproteinase 9 (MMP-9) has been found in several inflammatory diseases. Previous studies have shown that acetylcholine (ACh) reduced the levels of pro-inflammatory cytokines and decreased tissue damage. Therefore, this study was designed to explore the potential effects and mechanisms of ACh on MMP-9 production and cell migration in response to lipopolysaccharide (LPS) stimulation in RAW264.7 cells. Methods: MMP-9 expression and activity were induced by LPS in RAW264.7 cells, and examined by real-time PCR, western blotting and gelatin zymography, respectively. ELISA was used to determine the changes in MMP-9 secretion among the groups. Macrophage migration was evaluated using transwell migration assay. Knockdown of a7 nicotinic acetylcholine receptor (a7 nAChR) expression was performed using siRNA transfection. Results: Pre-treatment with ACh inhibited LPS-induced MMP-9 production and macrophage migration in RAW264.7 cells. These effects were abolished by the a7 nAChR antagonist methyllycaconitine (MLA) and a7 nAChR siRNA. The a7 nAChR agonist PNU282987 was found to have an effect similar to that of ACh. Moreover, ACh enhanced the expression of JAK2 and STAT3, and the JAK2 inhibitor AG490 and the STAT3 inhibitor static restored the effect of ACh. Meanwhile, ACh decreased the phosphorylation and nuclear translocation of NF-κB, and this effect was abrogated in the presence of MLA. In addition, the JAK2 and STAT3 inhibitor abolished the inhibitory effects of ACh on phosphorylation of NF-κB. Conclusions: Activation of a7 nAChR by ACh inhibited LPS-induced MMP-9 production and macrophage migration through the JAK2/STAT3 signaling pathway. These results provide novel insights into the anti-inflammatory effects and mechanisms of ACh.

Spermatogonial stem cells (SSCs), a unique population of male germ cells with self‐renewal ability, are the foundation for maintenance of spermatogenesis throughout the life of the male. Although many regulatory molecules essential for SSC self‐renewal have been identified, the fundamental mechanism underlying how SSCs acquire and maintain their self‐renewal activity remains largely to be elucidated. In recent years, many types of noncoding RNAs (ncRNAs) have been suggested to regulate the SSC self‐renewal through multiple ways, indicating ncRNAs play crucial roles in SSC self‐renewal. In this paper, we mainly focus on four types of ncRNAs including microRNA, long ncRNA, piwi‐interacting RNA, as well as circular RNAs, and reviewed their potential roles in SSC self‐renewal that discovered recently to help us gain a better understanding of molecular mechanisms by which ncRNAs perform their function in regulating SSC self‐renewal.

This is an Open Access article licensed under the terms of the Creative Commons AttributionNonCommercial 3.0 Unported license (CC BY-NC) (www.karger.com/OA-license), applicable to the online version of the article only. Distribution permitted for non-commercial purposes only. Key Words Acetylcholine • Muscarinic receptor • Calpain • Calpastatin • p38-MAPK • ApoptosisAbstract Background: Previous studies have shown that inflammation is associated with excessive activation of calpains. Acetylcholine (ACh) has been reported to inhibit pro-inflammatory cytokine release and protect against cardiomyocyte injury. However, there is no direct evidence regarding whether ACh can regulate calpains to exert cardioprotection. To this end, we investigated the effect of ACh on tumour necrosis factor alpha (TNF-α)-induced cardiomyocyte injury and further explored the underlying mechanism. Methods: Flow cytometry and transmission electron microscopy were performed to evaluate apoptosis and cellular ultrastructure. Western blotting was performed to assess changes in protein expression. siRNA was employed to silence specific proteins. Results: TNF-α treatment increased the expression of cleaved caspase-3, calpain-1 and p38-mitogen-activated protein kinase (p38-MAPK). The calpain inhibitor PD150606 and the p38-MAPK inhibitor SB203580 inhibited apoptosis induced by TNF-α. Moreover, SB203580 decreased the expression and activity of calpain-1, possibly related to the up-regulation of calpastatin. ACh significantly inhibited TNF-α-induced cell apoptosis, as evidenced by decreases in caspase-3 cleavage, p38-MAPK phosphorylation, and calpain-1 expression and activity as well as increases in calpastatin expression. These beneficial effects of ACh were abolished by atropine or M 2 AChR siRNA. Conclusion: Our results suggest that ACh ameliorated TNF-α-induced calpain activation by decreasing p38-MAPK phosphorylation and enhancing calpastatin expression, indicating that calpain may be an important link between inflammatory factors and myocardial cell apoptosis.M. Zhao and Y. Yang contributed equally to this work.

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It is well-accepted that inflammation plays an important role in the development of cardiac remodelling and that therapeutic approaches targeting inflammation can inhibit cardiac remodelling. Although a large amount of evidence indicates that activation of α7 nicotinic acetylcholine receptor (α7nAChR) causes an anti-inflammatory effect, the role of α7nAChR in cardiac remodelling and the underlying mechanism have not been established. To investigate the effect of the specific α7nAChR agonist, PNU282987, on cardiac remodelling induced by isoproterenol (ISO 60 mg/kg per day) in mice, the cardiomyocyte cross-sectional area (CSA) and collagen volume fraction were evaluated by hematoxylin and eosin (HE) and Masson staining, respectively. Cardiac function and ventricular wall thickness were measured by echocardiography. The protein expressions of collagen I, matrix metalloproteinase 9 (MMP-9), transforming growth factor β1 (TGF-β1), and Smad3 were analyzed by Western blot. ISO-induced cardiac hypertrophy, characterized by an increase in the heart weight/body weight ratio, CSA and ventricular wall thickness. Moreover, cardiac fibrosis indices, such as collagen volume fraction, MMP-9 and collagen I protein expression, were also increased by ISO. PNU282987 not only attenuated cardiac hypertrophy but also decreased the cardiac fibrosis induced by ISO. Furthermore, PNU282987 suppressed TGF-β1 protein expression and the phosphorylation of Smad3 induced by ISO. In conclusion, PNU282987 ameliorated the cardiac remodelling induced by ISO, which may be related to the TGF-β1/Smad3 pathway. These data imply that the α7nAChR may represent a novel therapeutic target for cardiac remodelling in many cardiovascular diseases.

The general toxicity of fine particulate matter (PM2.5) has been intensively studied, but its pulmonary toxicities are still not fully understood. To investigate the changes of lung tissue after PM2.5 exposure and identify the potential mechanisms of pulmonary toxicity, PM2.5 samples were firstly collected and analyzed. Next, different doses of PM2.5 samples (5 mg/kg, 10 mg/kg, 20 mg/kg) were intratracheally instilled into rats to simulate lung inhalation of polluted air. After instillation for eight weeks, morphological alterations of the lung were examined, and the levels of oxidative stress were detected. The data indicated that the major contributors to PM2.5 mass were organic carbon, elemental carbon, sulfate, nitrate, and ammonium. Different concentrations of PM2.5 could trigger oxidative stress through increasing reactive oxygen species (ROS) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels, and decreasing expression of antioxidant-related proteins (nuclear factor erythroid 2-related factor 2 (Nrf2), superoxide dismutase 1 (SOD1) and catalase). Histochemical staining and transmission electron microscopy displayed pulmonary inflammation, collagen deposition, mitochondrial swelling, and a decreasing number of multilamellar bodies in alveolar type II cells after PM2.5 exposure, which was related to PM2.5-induced oxidative stress. These results provide a basis for a better understanding of pulmonary impairment in response to PM2.5.

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Introduction: Oligopeptides exhibit great prospects for clinical application and its separation is of great importance in new drug development.Methods: To accurately predict the retention of pentapeptides with analogous structures in chromatography, the retention times of 57 pentapeptide derivatives in seven buffers at three temperatures and four mobile phase compositions were measured via reversed-phase high-performance liquid chromatography. The parameters (kHA, kA, and pKa) of the acid–base equilibrium were obtained by fitting the data corresponding to a sigmoidal function. We then studied the dependence of these parameters on the temperature (T), organic modifier composition (φ, methanol volume fraction), and polarity (PmN parameter). Finally, we proposed two six-parameter models with (1) pH and T and (2) pH and φ or PmN as the independent variables. These models were validated for their prediction capacities by linearly fitting the predicted retention factor k-value and the experimental k-value.Results: The results showed that logkHA and logkA exhibited linear relationships with 1/T, φ or PmN for all pentapeptides, especially for the acid pentapeptides. In the model of pH and T, the correlation coefficient (R2) of the acid pentapeptides was 0.8603, suggesting a certain prediction capability of chromatographic retention. Moreover, in the model of pH and φ or PmN, the R2 values of the acid and neutral pentapeptides were greater than 0.93, and the average root mean squared error was approximately 0.3, indicating that the k-values could be effectively predicted.Discussion: In summary, the two six-parameter models were appropriate to characterize the chromatographic retention of amphoteric compounds, especially the acid or neutral pentapeptides, and could predict the chromatographic retention of pentapeptide compounds.