Astragalus polysaccharides exerts anti‐infective activity by inducing human cathelicidin antimicrobial peptide LL‐37 in respiratory epithelial cells

Abstract

Astragalus polysaccharides (APS), one of the major active components in Astragalus membranaceus, is an effective immunomodulator used in the treatment of immunological diseases in China. However, the anti-infective action and mechanism of APS is not fully known. In the present study, we found that APS induced the expression of human cathelicidin antimicrobial peptide LL-37, a key host anti-infective molecule, in both mRNA and protein levels in respiratory epithelial cells HBE16 and A549. Furthermore, the lysate and supernatant from APS-treated HBE16 cells both exhibited an obvious antibacterial action, which was partially neutralizated by LL-37 monoclonal antibody. In addition, APS also significantly elevated the phosphorylation of p38 MAPK and JNK and caused the degradation of IκBα. Specific inhibitors of p38 MAPK, JNK, or NF-κB obviously abolished APS-induced LL-37 synthesis and antibacterial activity, respectively. Taken together, our results confirmed the enhancement of APS on LL-37 induction and antibacterial action in respiratory epithelial cells, which may be attributed to activation of p38 MAPK/JNK and NF-κB pathways. Furthermore, these results also supported the clinical application of APS in the treatment of infectious diseases.

Total flavonoids from sea buckthorn ameliorates lipopolysaccharide/cigarette smoke‐induced airway inflammation

“…Traditionally, medicinal plants and foods have been generally used to treat various human diseases for thousands in China (Zhao, Tan, et al, ; Zhao, Wang, et al, ). Furthermore, medicinal plants and foods are also the main resource of bioactive compounds, including flavonoids.…”

“…Traditional Chinese medicine plays an important role in the prevention and treatment of a variety of acute and chronic lung diseases, including chronic bronchitis (Liao, Hu, Chen, & Hung, ; Zhao, Tan, et al, ). Traditionally, sea buckthorn ( Hippophaë rhamnoides L.) fruit, a dual‐use resource of medicine and food, is used to treat cardiovascular diseases and lung disorders in traditional Chinese medicine and Tibetan medicine for a long history (Sayegh, Miglio, & Ray, ; Xu, Kaur, Dhillon, Tappia, & Dhalla, ).…”

A Systematic Review of Phytochemistry, Pharmacology and Pharmacokinetics on Astragali Radix: Implications for Astragali Radix as a Personalized Medicine

“…Moreover, APS can inhibit the expression of inflammatory factors by inhibiting NF-κB signaling pathway [161] (Figure 5⑤). Thus, it was concluded that APS could effectively inhibit asthma by inhibiting ER stress and reduce the excessive secretion of respiratory mucus and respiratory inflammation in ovalbumin-induced severe asthma mice [162].…”

Astragalus membranaceus–Derived Anti-Programmed Death-1 Monoclonal Antibodies with Immunomodulatory Therapeutic Effects against Tumors

“…Administration of APS in experimental animals can promote the expression of cytokine interleukin-(IL-) 1β, tumor necrosis factor α (TNF-α), and interferon-γ (IFN-γ) genes and proteins [5,6], which can effectively activate and increase the number of macrophages [7] and stimulate the proliferation of peripheral blood T cells [8]. Recently, one study showed that APS can enhance immunity by inducing the production of the cathelicidin-derived antimicrobial peptide LL-37 in human respiratory epithelial cells through the activation of the pathways of p38 MAPK/JNK and NF-κ [9]. Studies have demonstrated that in vaccine immunization, APS has great potential as a potent adjuvant, enhancing the effect of antigen presentation by improving the performance of class II major histocompatibility complex molecules, which facilitates lymphocyte proliferation, increases the number of antibodies in serum, and increases the secretion of cytokine [10,11].…”