Syringic acid attenuates acute lung injury by modulating macrophage polarization in LPS-induced mice

BACKGROUND

Acute lung injury (ALI) is a continuum of lung changes caused by multiple lung injuries, characterized by a syndrome of uncontrolled systemic inflammation that often leads to significant morbidity and death. Anti-inflammatory is one of its treatment methods, but there is no safe and available drug therapy. Syringic acid (SA) is a natural organic compound commonly found in a variety of plants, especially in certain woody plants and fruits. In modern pharmacological studies, SA has anti-inflammatory effects and therefore may be a potentially safe and available compound for the treatment of acute lung injury.

PURPOSE

This study attempts to reveal the protective mechanism of SA against ALI by affecting the polarization of macrophages and the activation of NF-κB signaling pathway. Trying to find a safer and more effective drug therapy for clinical use.

METHODS

We constructed the ALI model using C57BL/6 mice by intratracheal instillation of LPS (10 mg/kg). Histological analysis was performed with hematoxylin and eosin (H&E). The wet-dry ratio of the whole lung was measured to evaluate pulmonary edema. The effect of SA on macrophage M1-type was detected by flow cytometry. BCA protein quantification method was used to determine the total protein concentration in bronchoalveolar lavage fluid (BALF). The levels of Interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α in BALF were determined by the ELISA kits, and RT-qPCR was used to detect the expression levels of IL-6, IL-1β and TNF-α mRNA of lung tissue. Western blot was used to detect the expression levels of iNOS and COX-2 and the phosphorylation of p65 and IκBα in the NF-κB pathway in lung tissue. In vitro experiments were conducted with RAW267.4 cell inflammation model induced by 100 ng/ml LPS and A549 cell inflammation model induced by 10 μg/ml LPS. The effects of SA on M1-type and M2-type macrophages of RAW267.4 macrophages induced by LPS were detected by flow cytometry. The toxicity of compound SA to A549 cells was detected by MTT method which to determine the safe dose of SA. The expressions of COX-2 and the phosphorylation of p65 and IκBα protein in NF-κB pathway were detected by Western blot.

RESULTS

We found that the pre-treatment of SA significantly reduced the degree of lung injury, and the infiltration of neutrophils in the lung interstitium and alveolar space of the lung. The formation of transparent membrane in lung tissue and thickening of alveolar septum were significantly reduced compared with the model group, and the wet-dry ratio of the lung was also reduced. ELISA and RT-qPCR results showed that SA could significantly inhibit the production of IL-6, IL-1β, TNF-α. At the same time, SA could significantly inhibit the expression of iNOS and COX-2 proteins, and could inhibit the phosphorylation of p65 and IκBα proteins. in a dose-dependent manner. In vitro experiments, we found that flow cytometry showed that SA could significantly inhibit the polarization of macrophages from M0 type macrophages to M1-type macrophages, while SA could promote the polarization of M1-type macrophages to M2-type macrophages. The results of MTT assay showed that SA had no obvious cytotoxicity to A549 cells when the concentration was not higher than 80 μM, while LPS could promote the proliferation of A549 cells. In the study of anti-inflammatory effect, SA can significantly inhibit the expression of COX-2 and the phosphorylation of p65 and IκBα proteins in LPS-induced A549 cells.

CONCLUSION

SA has possessed a crucial anti-ALI role in LPS-induced mice. The mechanism was elucidated, suggesting that the inhibition of macrophage polarization to M1-type and the promotion of macrophage polarization to M2-type, as well as the inhibition of NF-κB pathway by SA may be the reasons for its anti-ALI. This finding provides important molecular evidence for the further application of SA in the clinical treatment of ALI.

Sinomenine ameliorates collagen-induced arthritis in mice by targeting GBP5 and regulating the P2X7 receptor to suppress NLRP3-related signaling pathways

Sinomenine (SIN) is an isoquinoline alkaloid isolated from Sinomenii Caulis, a traditional Chinese medicine used to treat rheumatoid arthritis (RA). Clinical trials have shown that SIN has comparable efficacy to methotrexate in treating patients with RA but with fewer adverse effects. In this study, we explored the anti-inflammatory effects and therapeutic targets of SIN in LPS-induced RAW264.7 cells and in collagen-induced arthritis (CIA) mice. LPS-induced RAW264.7 cells were pretreated with SIN (160, 320, 640 µM); and CIA mice were administered SIN (25, 50 and 100 mg·kg-1·d-1, i.p.) for 30 days. We first conducted a solvent-induced protein precipitation (SIP) assay in LPS-stimulated RAW264.7 cells and found positive evidence for the direct binding of SIN to guanylate-binding protein 5 (GBP5), which was supported by molecular simulation docking, proteomics, and binding affinity assays (KD = 3.486 µM). More importantly, SIN treatment markedly decreased the expression levels of proteins involved in the GBP5/P2X7R-NLRP3 pathways in both LPS-induced RAW264.7 cells and the paw tissue of CIA mice. Moreover, the levels of IL-1β, IL-18, IL-6, and TNF-α in both the supernatant of inflammatory cells and the serum of CIA mice were significantly reduced. This study illustrates a novel anti-inflammatory mechanism of SIN; SIN suppresses the activity of NLRP3-related pathways by competitively binding GBP5 and downregulating P2X7R protein expression, which ultimately contributes to the reduction of IL-1β and IL-18 production. The binding specificity of SIN to GBP5 and its inhibitory effect on GBP5 activity suggest that SIN has great potential as a specific GBP5 antagonist.

Determination of sparstolonin B by ultra-high performance liquid chromatography coupled with triple quadrupole mass spectrometry: application to pharmacokinetic study of sparstolonin B in rat plasma

Sparstolonin B (SsnB), a spontaneous isocoumarin compound isolated from the tuber of Scirpus yagara Ohwi. (Cyperaceae), possesses potent anti-inflammatory and antitumor activity. In the present study, a rapid and simple UHPLC/MS/MS method for determination of SsnB in rat plasma was developed and validated. Plasma samples were pretreated by liquid-liquid extraction with ethyl acetate containing rhein as an internal standard and separated on a C18 column at 35 °C, with a gradient mobile phase consisting of acetonitrile and water containing 0.2% (v/v) formic acid within 2.1 min. MS/MS detection was accomplished in multiple reaction monitoring mode with negative electrospray ionization. The precursor-product ion transitions were m/z 266.9 [M-H](-)  → m/z 211.0 for SsnB and m/z 283.2 [M-H](-)  → m/z 239.0 for IS. The intra- and inter-day precision (RSD) was <8.98% and the accuracy (RE) ranged from -7.40 to 4.50%. The extraction recoveries ranged from 96.28 to 97.30%. The pharmacokinetic parameters were calculated using Win Nonlin53 software. The absolute bioavailability of SsnB was estimated to be 6.98%. The proposed method was successfully applied to a pharmacokinetic study of SsnB in rats after intravenous administration with a dose of 0.5 mg/kg and oral administration at a dose of 5 mg/kg.

Oridonin suppresses the proliferation of human pancreatic carcinoma SW1990 cells

AIM: To investigate whether oridonin has antiproliferation effects against human pancreatic carcinoma SW1990 cells and to explore possible mechanisms involved.

METHODS: SW1990 cells were treated with different concentrations of oridonin. Cell proliferation was measured by MTT assay. Cell morphological changes were observed by laser confocal microscopy after double immunofluorescence staining. Cell apoptosis was detected by flow cytometry (FCM).

RESULTS: Treatment with oridonin significantly inhibited the growth of SW1990 cells. After treatment with oridonin, apoptosis-related morphological changes, such as condensation of chromatin and nuclear fragmentation, were observed in SW1990 cells. The fluorescence intensity of β-actin in the cytoplasm was increased, especially in the perinuclear area. The early apoptotic rates of SW1990 cells treated with 12.5, 25.0 and 50.0 µmol/L oridonin were significantly higher than those of control cells (2.17% ± 0.57%, 5.83% ± 0.57%, 4.43% ± 0.78% vs 0.30% ± 0.17%, all P < 0.05). The late apoptotic and cell necrosis rates were also significantly higher in oridonin-treated cells than in control cells (5.10% ± 0.98%, 7.03% ± 1.52%, 10.13% ± 0. 70% vs 2.63% ± 0.06%, all P < 0.05).

CONCLUSION: Oridonin can significantly inhibit proliferation and induce apoptosis of SW1990 cells perhaps by altering β-actin depolymerization/polymerization.

Chemical correlation between Gegen Qinlian dispensing granule and its four raw herbs by LC fingerprint

Gegen Qinlian dispensing granule, a favorite composite formula, is a combination of Radix Puerariae Lobatae, Radix Scutellariae, Rhizoma Coptidis and Radix et Rhizoma Glycyrrhizae Praeparata cum Melle. To develop a method to overall evaluate correlation between the formula and its four raw herbs, LC fingerprints of the formula and its raw herbs were developed and LC-DAD-MS was employed to identify the components in the formula fingerprint. According to the characteristic fragmentation behavior of known flavonoids, alkaloids and saponins isolated from the four raw herbs as well as retention time, UV and MS data of detected compounds, a total of 23 constituents in the formula fingerprint were structurally characterized. Chemical correlation between the formula and the four crude herbs was evaluated qualitatively and quantitatively by the developed LC fingerprints. The results showed that 8 components in the formula fingerprint were addressed to Radix Puerariae Lobatae, 11 to Radix Scutellariae, 7 to Rhizoma Coptidis, 3 to Radix et Rhizoma Glycyrrhizae Praeparata cum Melle, and that the relative area ratios of the common peaks in the formula vary slightly in comparison with corresponding ratios in its crude herbs, demonstrating the chemical constituents in the formula have patterns similar to those in its crude herbs.

Screening and analyzing the potential bioactive components from Shaofu Zhuyu decoction, using human umbilical vein endothelial cell extraction and high-performance liquid chromatography coupled with mass spectrometry

In this paper, a useful method for screening and analyzing the potential bioactive components in bioassay-guided fraction (SF-11) from Shaofu Zhuyu decoction was developed using human umbilical vein endothelial cell (HUVEC) extraction and high-performance liquid chromatography coupled with Q-TOF/MS spectrometry. In addition, the protective effects on HUVEC damage induced by adrenaline in vitro were also investigated. The results showed that SF-11 significantly inhibited the endothelin (ET) release and reversed the NO secretion of HUVEC (p < 0.05), and promoted the PGI(2) release of HUVEC (p < 0.05). Two effective components, paeoniflorin and typhaneoside, from SF-11 were screened and identified using live cell extract and HPLC coupled with Q-TOF/MS spectrometry. The compounds, paeoniflorin and typhaneoside, showed significantly inhibiting effects on the ET release and reversing of NO secretion of HUVEC (p < 0.05), with similar effects to SF-11, and promoting the PGI(2) release of HUVEC at the concentration of 0.208 and 0.013 micromol/mL, respectively (p < 0.05). These data indicated that the method of live cell extraction coupled with HPLC-MS technology is feasible, rapid and useful for screening and analyzing potential bioactive components from TCMs.

A report of two cases of chronic serious manganese poisoning treated with sodium para-aminosalicylic acid

Two cases of chronic manganese poisoning were treated with sodium para-aminosalicylic acid (PAS-Na; 6 g/day in 500 ml of 10% glucose solution by intravenous drip). The results indicated that one had been clinically cured and that the other had obviously improved in clinical symptoms and signs. Thus PAS-Na appears to be an effective drug for treatment of serious chronic manganese poisoning.