Secoeudesma sesquiterpenes lactone A alleviates inflammation and offers adjuvant protection in severe infection of carbapenem-resistant Klebsiella pneumoniae

Dehydrozaluzanin C- derivative protects septic mice by alleviating over-activated inflammatory response and promoting the phagocytosis of macrophages

Host-directed therapy (HDT) is a new adjuvant strategy that interfere with host cell factors that are required by a pathogen for replication or persistence. In this study, we assessed the effect of dehydrozaluzanin C-derivative (DHZD), a modified compound from dehydrozaluzanin C (DHZC), as a potential HDT agent for severe infection. LPS-induced septic mouse model and Carbapenem resistant Klebsiella pneumoniae (CRKP) infection mouse model was used for testing in vivo. RAW264.7 cells, mouse primary macrophages, and DCs were used for in vitro experiments. Dexamethasone (DXM) was used as a positive control agent. DHZD ameliorated tissue damage (lung, kidney, and liver) and excessive inflammatory response induced by LPS or CRKP infection in mice. Also, DHZD improved the hypothermic symptoms of acute peritonitis induced by CRKP, inhibited heat-killed CRKP (HK-CRKP)-induced inflammatory response in macrophages, and upregulated the proportions of phagocytic cell types in lungs. In vitro data suggested that DHZD decreases LPS-stimulated expression of IL-6, TNF-α and MCP-1 via PI3K/Akt/p70S6K signaling pathway in macrophages. Interestingly, the combined treatment group of DXM and DHZD had a higher survival rate and lower level of IL-6 than those of the DXM-treated group; the combination of DHZD and DXM played a synergistic role in decreasing IL-6 secretion in sera. Moreover, the phagocytic receptor CD36 was increased by DHZD in macrophages, which was accompanied by increased bacterial phagocytosis in a clathrin- and actin-dependent manner. This data suggests that DHZD may be a potential drug candidate for treating bacterial infections.

Preventive nasal administration of flagellin restores antimicrobial effect of gentamicin and protects against a multidrug-resistant strain of Pseudomonas aeruginosa

The increasing prevalence of multidrug-resistant Pseudomonas aeruginosa (PA) is a significant concern for chronic respiratory disease exacerbations. Host-directed drugs, such as flagellin, an agonist of toll-like receptor 5 (TLR5), have emerged as a promising solution. In this study, we evaluated the prophylactic intranasal administration of flagellin against a multidrug-resistant strain of PA (PAMDR) in mice and assessed the possible synergy with the antibiotic gentamicin (GNT). The results indicated that flagellin treatment before infection decreased bacterial load in the lungs, likely due to an increase in neutrophil recruitment, and reduced signs of inflammation, including proinflammatory cytokines. The combination of flagellin and GNT showed a synergistic effect, decreasing even more the bacterial load and increasing mice survival rates, in comparison to mice pre-treated only with flagellin. These findings suggest that preventive nasal administration of flagellin could restore the effect of GNT against MDR strains of PA, paving the way for the use of flagellin in vulnerable patients with chronic respiratory diseases.

Fei-Yan-Qing-Hua decoction decreases hyperinflammation by inhibiting HMGB1/RAGE signaling and promotes bacterial phagocytosis in the treatment of sepsis

ETHNOPHARMACOLOGICAL RELEVANCE

Fei-Yan-Qing-Hua decoction (FYQHD), derived from the renowned formula Ma Xing Shi Gan tang documented in Zhang Zhong Jing's "Treatise on Exogenous Febrile Disease" during the Han Dynasty, has demonstrated notable efficacy in the clinical treatment of pneumonia resulting from bacterial infection. However, its molecular mechanisms underlying the therapeutic effects remains elusive.

AIM OF THE STUDY

This study aimed to investigate the protective effects of FYQHD against lipopolysaccharide (LPS) and carbapenem-resistant Klebsiella pneumoniae (CRKP)-induced sepsis in mice and to elucidate its specific mechanism of action.

MATERIALS AND METHODS

Sepsis models were established in mice through intraperitoneal injection of LPS or CRKP. FYQHD was administered via gavage at low and high doses. Serum cytokines, bacterial load, and pathological damage were assessed using enzyme-linked immunosorbent assay (ELISA), minimal inhibitory concentration (MIC) detection, and hematoxylin and eosin staining (H&E), respectively. In vitro, the immunoregulatory effects of FYQHD on macrophages were investigated through ELISA, MIC, quantitative real-time PCR (Q-PCR), immunofluorescence, Western blot, and a network pharmacological approach.

RESULTS

The application of FYQHD in the treatment of LPS or CRKP-induced septic mouse models revealed significant outcomes. FYQHD increased the survival rate of mice exposed to a lethal dose of LPS to 33.3%, prevented hypothermia (with a rise of 3.58 °C), reduced pro-inflammatory variables (including TNF-α, IL-6, and MCP-1), and mitigated tissue damage in LPS or CRKP-induced septic mice. Additionally, FYQHD decreased bacterial load in CRKP-infected mice. In vitro, FYQHD suppressed the expression of inflammatory cytokines in macrophages activated by LPS or HK-CRKP. Mechanistically, FYQHD inhibited the PI3K/AKT/mTOR/4E-BP1 signaling pathway, thereby suppressing the translational level of inflammatory cytokines. Furthermore, it reduced the expression of HMGB1/RAGE, a positive feedback loop in the inflammatory response. Moreover, FYQHD was found to enhance the phagocytic activity of macrophages by upregulating the expression of phagocytic receptors such as CD169 and SR-A1.

CONCLUSION

FYQHD provides protection against bacterial sepsis by concurrently inhibiting the inflammatory response and augmenting the phagocytic ability of immune cells.

Cytokine Storm in Acute Viral Respiratory Injury: Role of Qing-Fei-Pai-Du Decoction in Inhibiting the Infiltration of Neutrophils and Macrophages through TAK1/IKK/NF-[Formula: see text]B Pathway

COVID-19 has posed unprecedented challenges to global public health since its outbreak. The Qing-Fei-Pai-Du decoction (QFPDD), a Chinese herbal formula, is widely used in China to treat COVID-19. It exerts an impressive therapeutic effect by inhibiting the progression from mild to critical disease in the clinic. However, the underlying mechanisms remain obscure. Both SARS-CoV-2 and influenza viruses elicit similar pathological processes. Their severe manifestations, such as acute respiratory distress syndrome (ARDS), multiple organ failure (MOF), and viral sepsis, are correlated with the cytokine storm. During flu infection, QFPDD reduced the lung indexes and downregulated the expressions of MCP-1, TNF-[Formula: see text], IL-6, and IL-1[Formula: see text] in broncho-alveolar lavage fluid (BALF), lungs, or serum samples. The infiltration of neutrophils and inflammatory monocytes in lungs was decreased dramatically, and lung injury was ameliorated in QFPDD-treated flu mice. In addition, QFPDD also inhibited the polarization of M1 macrophages and downregulated the expressions of IL-6, TNF-[Formula: see text], MIP-2, MCP-1, and IP-10, while also upregulating the IL-10 expression. The phosphorylated TAK1, IKK[Formula: see text]/[Formula: see text], and I[Formula: see text]B[Formula: see text] and the subsequent translocation of phosphorylated p65 into the nuclei were decreased by QFPDD. These findings indicated that QFPDD reduces the intensity of the cytokine storm by inhibiting the NF-[Formula: see text]B signaling pathway during severe viral infections, thereby providing theoretical and experimental support for its clinical application in respiratory viral infections.

SESLA suppresses the activation of macrophages and dendritic cells after Gram-positive bacterial challenge

BACKGROUND

Secoeudesma sesquiterpenes lactone A (SESLA) is a sesquiterpene derived from Inula japonica Thunb. and is known to possess many pharmacological properties, e.g., anti-tumor and anti-inflammatory activities. However, the immunomodulatory role of SESLA in gram-positive (G⁺) bacterial infection is not clear.

MATERIALS AND METHODS

To set up a G⁺ bacterial infection model in vitro, we carried out a bacterial mimic (PGN or Pam3CSK4) or Methicillin-resistant Staphylococcus aureus (MRSA) stimulated experiment using macrophages or dendritic cells (DCs). ELISA and qPCR were performed to measure the expression of inflammatory cytokines. Flow cytometry was used to detect the expression of MHC II and co-stimulatory molecules on the surface of DCs. The network pharmacology was used to identify the molecular mechanism and potential targets of SESLA that are predicted to be involved in the MRSA-elicited inflammation. Western blot and dual luciferase reporter assay were adopted to certify possible molecular mechanism of SESLA.

RESULTS

This study demonstrated that SESLA treatment significantly reduced the levels of inflammatory cytokines stimulated by PGN, Pam3CSK4 or even MRSA in vitro, and it also reduced PGN-induced expression of MHC II and co-stimulatory molecules on the surface of DCs. Mechanistically, the inhibition of IκBα phosphorylation and the suppression of T cells activation could account for its anti-inflammatory activity.

CONCLUSION

The present study validated the notable anti-inflammatory activity of SESLA and discovered its previously uncharacterized immunoregulatory role and the underlying mechanism in G⁺ bacterial infections. Overall, SESLA has a potential to be an antibiotic adjuvant for the treatment of G⁺ bacterial infections.

Anti-Inflammatory and Immunoregulatory Action of Sesquiterpene Lactones

Sesquiterpene lactones (SL), characterized by their high prevalence in the Asteraceae family, are one of the major groups of secondary metabolites found in plants. Researchers from distinct research fields, including pharmacology, medicine, and agriculture, are interested in their biological potential. With new SL discovered in the last years, new biological activities have been tested, different action mechanisms (synergistic and/or antagonistic effects), as well as molecular structure–activity relationships described. The review identifies the main sesquiterpene lactones with interconnections between immune responses and anti-inflammatory actions, within different cellular models as well in in vivo studies. Bioaccessibility and bioavailability, as well as molecular structure–activity relationships are addressed. Additionally, plant metabolic engineering, and the impact of sesquiterpene lactone extraction methodologies are presented, with the perspective of biological activity enhancement. Sesquiterpene lactones derivatives are also addressed. This review summarizes the current knowledge regarding the therapeutic potential of sesquiterpene lactones within immune and inflammatory activities, highlighting trends and opportunities for their pharmaceutical/clinical use.

Japonicone A and related dimeric sesquiterpene lactones: molecular targets and mechanisms of anticancer activity

OBJECTIVE AND DESIGN

Japonicone A (Jap-A) is a sesquiterpene lactone (SL) dimer isolated from the plant Inula japonica Thunb. and the leading compound in the japonicone series of SL dimers which comprises 25 members (Jap-A to Jap-Y). We have analyzed the anticancer properties of Jap-A and the associated molecular targets.

METHODS

All literature data on japonicones and related SL dimers, including inulanolide A (Inu-A) and lineariifolianoid A (Lin-A) have been analyzed. Molecular models of the compound/target interactions were constructed to support our analysis.

RESULTS

Inulae Flos (Xuan Fu Hua) is used in traditional medicine in China and Korea to treat inflammatory diseases. The plant contains diverse japonicones and structurally related SL dimers. The interactions of Jap-A with the two main proteins, the pro-inflammatory cytokine TNF-α and the ubiquitin ligase MDM2, are at the origin of the anti-inflammatory and anticancer effects. Molecular docking analyses suggest that Inu-A is better adapted than Lin-A and Jap-A to form stable complexes with both TNF-α and MDM2. Jap-A exhibits marked capacities to inhibit cancer cell proliferation and dissemination and to trigger apoptosis, both in vitro and in vivo in several tumor models in mice. Its analogue Inu-A is more potent, functioning as a dual inhibitor of the MDM2-NFAT1 pathway.

CONCLUSION

This review shed some new light on the molecular targets and potential therapeutic benefits of these SL dimers and should help the design of novel anticancer agents derived from these compounds.

A review of the botany, traditional uses, phytochemistry, and pharmacology of the Flos Inulae

ETHNOPHARMACOLOGICAL RELEVANCE

Plants of the genus Inula have long been used as an ethnomedicine in Asia, Europe, and North America for its high medicinal value and health benefits. Inula japonica Thunb. (I. japonica) and Inula britanica L. (I. britanica) are included in Chinese Pharmacopoeia (2020 edition) as the traditional Chinese medicine Flos inulae (FI). In TCM, FI tastes bitter, pungent, and salt, with warm nature and has the functions of water removal, reduction in nausea, and prevention of vomiting and is often used for cold-related coughs, sputum, wheezing coughs, vomiting, belching and other related diseases. In addition, Inula japonica Thunb is used as a botanical medicine in Korea and Inula britannica L. is also used as a traditional plant medicine in Iran.

AIM OF THE STUDY

This paper collects the relevant research literature (1970-2021) and provides a systematic summary of the botany, ethnopharmacology, processing, phytochemistry, pharmacology, toxicity, analytical methods and quality control of FI to explore its potential and expand its scope for better clinical application.

MATERIALS AND METHODS

Information on Inula japonica Thunb. and Inula britanica L. was collected from scientific databases (1970-2021), including Google Scholar, Baidu Scholar, Springer, PubMed, CNKI and Wan Fang DATA. Information was also collected from classic books of Chinese herbal medicine and Ph.D. and M.Sc. theses.

RESULTS

More than 200 chemical compounds have been isolated from Inula japonica Thunb. and Inula britanica L., including sesquiterpenes, flavonoids, volatile oils, triterpenoids, diterpenoid glycosides, monoterpenoids, polysaccharides, steroid and small molecule acids. Based on a wide variety of chemically active ingredients, FI has a wide range of pharmacological effects. Modern pharmacological research has proven that the pharmacological effects of FI include anti-inflammatory, antitumor, antioxidant, antiallergy, antidiabetic, blood lipid reduction, skin whitening, liver protection, anticonstipation, and antinociceptive effects.

CONCLUSIONS

FI is a very important traditional Chinese herbal medicine with anti-inflammatory antitumor, antioxidant, antiallergy, antidiabetic and other pharmacological effects that can treat a variety of related diseases. This paper summarizes the botany, ethnopharmacology, processing, phytochemistry, pharmacology, toxicity, analytical methods, and quality control of FI. However, the research on the processing, toxicity and quality control of FI is currently too shallow, especially concerning the relationship between the changes in active components before and after processing and the changes in its pharmacological action, which remains unclear. There are few toxicity experiments conducted with FI, so it is impossible to evaluate the safety of FI objectively and impartially. There are also few studies on the material basis and doses of FI causing toxicity and side effects, and more in-depth and concrete researches should be carried out in the future regarding these aspects. Furthermore, to ensure effective and safe clinical medication, we should also pay attention to the mixed use of FI in various regions of China to control the quality of the FI plant.

Baicalin protects mice from infection with methicillin-resistant Staphylococcus aureus via alleviating inflammatory response

Sepsis was redefined as life-threatening organ dysfunction caused by a dysregulated host response to infection in 2016. One of its most common causes is Staphylococcus aureus, especially methicillin-resistant Staphylococcus aureus (MRSA), which leads to a significant increase in morbidity and mortality. Therefore, innovative and effective approaches to combat MRSA infection are urgently needed. Recently, host-directed therapy (HDT) has become a new strategy in the treatment of infectious diseases, especially those caused by antibiotic-resistant bacteria. Baicalin (BAI) is the predominant flavonoid and bioactive compound isolated from the roots of Radix Scutellariae (Huang Qin), a kind of traditional Chinese medicine. It has been reported that BAI exhibits multiple biological properties such as anti-oxidant, antitumor, and anti-inflammatory activities. However, the therapeutic role of BAI in MRSA infection is still unknown. In this study, it is found that BAI treatment inhibited the production of IL-6, TNF-α, and other cytokines from MRSA- or bacterial mimics-stimulated Mϕs and dendritic cells (DCs). BAI played an anti-inflammatory role by inhibiting the activation of ERK, JNK MAPK, and NF-κB pathways. Moreover, the serum level of TNF-α was decreased, whereas IL-10 was increased, in mice injected with MRSA. Furthermore, the bacterial load in livers and kidneys were further decreased by the combination of BAI and vancomycin (VAN), which might account for the amelioration of tissue damage. BAI reduced the high mortality rate caused by MRSA infection. Collectively, the results suggested that BAI may be a viable candidate of HDT strategy against severe sepsis caused by antibiotic-resistant bacteria such as MRSA.