Berkeleyacetal C, a meroterpenoid isolated from the fungus Penicillium purpurogenum MHZ 111, exerts anti-inflammatory effects via inhibiting NF-κB, ERK1/2 and IRF3 signaling pathways

Angesinenolide B, A Phthalide Dimeric Peroxide, Exerts Anti-Inflammatory Properties by Suppressing MAPK/STATs Signaling Pathways and ROS Production

Purpose

Angesinenolide B (ASB), a phthalide dimer with a peroxy bridge, is uniquely isolated from Chinese medicine Angelica sinensis radix and demonstrates significant anti-inflammatory properties. The objective of the current study was to evaluate the anti-inflammatory function of ASB and the potential mechanism in lipopolysaccharide (LPS)-stimulated macrophages and CuSO4-induced zebrafish models.

Methods

The level of nitric oxide (NO), a proinflammatory mediator, in LPS-stimulated RAW264.7 cells was quantified using Griess method. ELISA was employed to investigate the generation of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), while qRT-PCR was utilized to analyze the mRNA expressions of TNF-α, IL-6, inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2). Fluorescence microscopy and flow cytometry were employed for the determination of ROS generation. Western blot and immunofluorescence techniques were utilized to assess the impact of ASB on iNOS and COX-2, and on the NF-κB, MAPK and STATs signaling pathways. Moreover, the affinities between ASB and the target proteins were verified by molecular docking analysis. In vivo, ROS generation was explored using fluorescent probe DCFH-DA, and the TNF-α and IL-6 mRNA expressions were also evaluated in CuSO4-induced zebrafish inflammation model.

Results

ASB treatment was found to suppress the levels of NO, TNF-α, IL-6 and ROS, restrain the expressions of iNOS and COX-2 proteins and mRNA, as well as down-regulate MAPK and STATs signaling pathways in LPS-stimulated RAW264.7 cells. Furthermore, the administration of ASB effectively attenuated the overproduction ROS and the high mRNA expressions of TNF-α and IL-6 in a zebrafish model of inflammation induced by CuSO4.

Conclusion

ASB has the potentiality to reduce the levels of proinflammatory mediators and cytokines, decrease ROS production, and also down-regulate the MAPK and STATs signaling pathways, thereby exerting an anti-inflammatory effect. This implies that ASB could potentially serve as a viable approach for addressing inflammatory conditions.

Target Discovery of Dhilirane-Type Meroterpenoids by Biosynthesis Guidance and Tailoring Enzyme Catalysis

Dhilirane-type meroterpenoids (DMs) featuring a 6/6/6/5/5 ring system represent a rare group of fungal meroterpenoids. To date, merely 11 DMs have been isolated or derived, leaving their chemical diversity predominantly unexplored. Herein, we leverage an understanding of biosynthesis to develop a workflow for discovery of DMs by genome mining, metabolite analysis, and tailoring enzyme catalysis. Twenty-three new DMs, including seven unprecedented scaffolds, were consequently identified. An α-ketoglutarate (α-KG)-dependent oxygenase DhiD was found to catalyze the stereodivergent ring contraction of dhilirolide D to form the dhilirane skeleton; while the cytochrome P450 DhiH reshaped the structural diversity by establishing diverse C-C bonds and oxidation. Crystallographic and mutagenesis experiments provide a molecular basis for the DhiD reaction and its stereodivergent products. Notably, DhiD exhibits substrate-controlled catalytic versatility in the chemical expansion of DMs through ring contraction, hydroxylation, dehydrogenation, epoxidation, isomerization, epimerization, and α-ketol cleavage. Bioassay results demonstrated that the obtained meroterpenoids exhibited anti-inflammatory and insecticidal activities. Our work provides insight into nature's arsenal for DM biosynthesis and the functional versatility of α-KG-dependent oxygenase and P450, which can be applied for target discovery and diversification of DM-type natural products.

Seco and Nor-seco Isodhilarane-Type Meroterpenoids from Penicillium purpurogenum and the Configuration Revisions of Related Compounds

Seco and nor-seco isodhilarane-type meroterpenoids (SIMs and NSIMs) are mainly found in Penicillium fungi and have been characterized by highly congested polycyclic skeletons and a broad range of bioactivities. However, the literature reports inconsistent configuration assignments for some SIMs and NSIMs, due to their complex polycyclic systems and multichiral centers. Herein, we described eight SIMs and NSIMs isolated from the EtOAc extract of Penicillium purpurogenum, which led to the configuration revisions of purpurogenolide C (1a), berkeleyacetal B (2a), chrysogenolide F (3a), and berkeleyacetal C (4a) as compounds 1-4, respectively. Furthermore, extensive re-evaluation of the experimental and computational ¹³C NMR chemical shifts of the reported 39 SIMs and NSIMs provided an empirical approach for determining the C-9 relative configuration, according to the ¹³C NMR chemical shifts of C-9, which contributed to the configuration revisions of another three SIMs (5a and 6a) and NSIMs (7a), denoted as compounds 5-7, respectively. Biological assays indicated that compound 3 exhibited cytotoxic activity against HepG2 and A549 cell lines with IC₅₀ values of 5.58 and 6.80 μM, respectively. Compounds 2-4, 8, 9, and 32 showed moderate hepatoprotective activity at 10 μM in the APAP-induced HepG2 cell injury model.

Synthetic Studies toward the Berkeleyacetal Core Architecture

Berkeleyacetals are structurally complex natural products that have shown potent anti-inflammatory activity. The presence of a highly dense oxygen functionality and a polycyclic ring system presents significant synthetic challenges. Herein, we report an efficient strategy for the construction of the tetracyclic core system of berkeleyacetal. Our synthetic strategy features two cycloadditions ([4+2] and [5+2]) to forge the tetracyclic core and Achmatowicz rearrangement for the preparation of the cyclization substrates containing B and E rings.

Marine-Derived Penicillium purpurogenum Reduces Tumor Size and Ameliorates Inflammation in an Erlich Mice Model

Background: This study addresses the antitumoral properties of Penicillium purpurogenum isolated from a polluted lagoon in Northeastern Brazil. Methods: Ethyl Acetate Extracellular Extract (EAE) was used. The metabolites were studied using direct infusion mass spectrometry. The solid Ehrlich tumor model was used for antitumor activity. Female Swiss mice were divided into groups (n = 10/group) as follows: The negative control (CTL−), treated with a phosphate buffered solution; the positive control (CTL+), treated with cyclophosphamide (25 mg/kg); extract treatments at doses of 4, 20, and 100 mg/kg; animals without tumors or treatments (Sham); and animals without tumors treated with an intermediate dose (EAE20). All treatments were performed intraperitoneally, daily, for 15 days. Subsequently, the animals were euthanized, and the tumor, lymphoid organs, and serum were used for immunological, histological, and biochemical parameter evaluations. Results: The extract was rich in meroterpenoids. All doses significantly reduced tumor size, and the 20 and 100 mg/kg doses reduced tumor-associated inflammation and tumor necrosis. The extract also reduced the cellular infiltration of lymphoid organs and circulating TNF-α levels. The extract did not induce weight loss or renal and hepatic toxic changes. Conclusions: These results indicate that P. purpurogenum exhibits immunomodulatory and antitumor properties in vivo. Thus, fungal fermentation is a valid biotechnological approach to the production of antitumor agents.

Remifentanil upregulates hepatic IL-18 binding protein (IL-18BP) expression through transcriptional control

Interleukin (IL)-18 plays an important role in liver ischemia/reperfusion (I/R) injury. We have previously demonstrated that remifentanil protects against liver I/R injury by upregulating the hepatic expression of IL-18-binding protein (IL-18BP), a natural IL-18 inhibitor. The current study was performed to further clarify the effects of remifentanil on IL-18BP expression in the liver as well as investigate the underlying mechanisms. In Sprague-Dawley (SD) rats, we demonstrated that remifentanil significantly increased the expression of IL-18BP in normal rat liver tissue over a 24-h time period with maximal expression at 24 h after treatment. The upregulation of remifentanil on IL-18BP expression displayed similar trends in in vitro cellular studies, including mouse primary hepatocytes, normal human hepatocyte LO2, and mouse hepatoma cells Hep1-6. In LO2 cells, preexposure of the cells to remifentanil significantly inhibited IL-18-activated p65 NF-κB phosphorylation, and the inhibition was absent when the cells were transfected with IL-18BP siRNA, indicating the functional effects of IL-18BP induced by remifentanil. Pretreatment with actinomycin D abolished remifentanil-induced upregulation of IL-18BP mRNA, suggesting that the induction occurred at the transcriptional level. This was further supported by the luciferase reporter assay, which demonstrated that remifentanil treatment significantly increased transcription of the IL-18BP promoter. Both western blot analysis and ChIP assays showed that STAT1 and C/EBP β were activated by remifentanil. Furthermore, remifentanil failed to upregulate IL-18BP expression after silencing STAT1 or C/EBP β gene expression. These findings demonstrate that remifentanil could upregulate hepatic IL-18BP expression through transcriptional activation of the IL-18BP promoter, and STAT1 and C/EBP β are two key transcriptional factors involved in this process.

COPD rat model is more susceptible to cold stress and PM2.5 exposure and the underlying mechanism

The purpose of this study is to verify the hypothesis that chronic obstructive pulmonary disease (COPD) model rat is more susceptible to cold stress and fine particulate matter (PM_2.5) exposure than the healthy rat, and explore the related mechanism. COPD rat model, established with cigarette smoke and lipopolysaccharide intratracheal instillation, were exposed to cold stress (0 °C) and PM_2.5 (0, 3.2, 12.8 mg/ml). After that, the levels of superoxide dismutase, inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), monocyte chemotactic protein 1 (MCP-1) and angiotensin Ⅱ (Ang-Ⅱ) in lung were measured, as well as the expression levels of lung 8-hydroxy-2-deoxyguanosine (8-OHdG), nuclear factor kappa B (NF-κB), heme-oxygenase-1 (HO-1) and nuclear factor erythroid-2-related factor 2 (Nrf2). There were significant positive relationships between PM_2.5 and lung level of iNOS, TNF-α, MCP-1 and Ang-Ⅱ, lung function and pathologic damage in COPD rats. The HO-1, NF-κB and 8-OHdG were found highly expressed in COPD rat lung, particularly at the higher PM_2.5 dose of cold stress groups, while Nrf2 was found declined. Thus, COPD rats may be more susceptible to cold stress and PM_2.5 exposure. Cold stress may aggravate PM_2.5-induced toxic effects in the lung of COPD rats through increasing Ang-Ⅱ/NF-κB signaling pathway and suppressing Nrf2 signaling pathway.