Machilin D Promotes Apoptosis and Autophagy, and Inhibits Necroptosis in Human Oral Squamous Cell Carcinoma Cells.

Oral squamous cell carcinoma (OSCC) accounts for about 90% of all head and neck cancers, the prognosis is very poor, and there are no effective targeted therapies. Herein, we isolated Machilin D (Mach), a lignin, from the roots of Saururus chinensis (S. chinensis) and assessed its inhibitory effects on OSCC. Herein, Mach had significant cytotoxicity against human OSCC cells and showed inhibitory effects against cell adhesion, migration, and invasion by inhibiting adhesion molecules, including the FAK/Src pathway. Mach suppressed the PI3K/AKT/mTOR/p70S6K pathway and MAPKs, leading to apoptotic cell death. We investigated other modes of programmed cell death in these cells and found that Mach increased LC3I/II and Beclin1 and decreased p62, leading to autophagosomes, and suppressed the necroptosis-regulatory proteins RIP1 and MLKL. Our findings provide evidence that the inhibitory effects of Mach against human YD-10B OSCC cells are related to the promotion of apoptosis and autophagy and inhibition of necroptosis and are mediated via focal adhesion molecules.

Collismycin C reduces HMGB1-mediated septic responses and improves survival rate in septic mice.

We examined the effects of a 2,2'-bipyridine containing natural product, collismycin C on high mobility group box 1 (HMGB1, septic mediator)-mediated septic responses and survival rate in a mouse sepsis model. Collismycin C inhibited the HMGB1 release and downregulated HMGB1-mediated inflammatory responses in human endothelial cells. Collismycin C also inhibited HMGB1-induced hyperpermeability and leukocyte migration in mice. In addition, collismycin C treatment reduced CLP-induced HMGB1 release and sepsis-related mortality and pulmonary damage in vivo. Our results indicate that collismycin C is a potential therapeutic agent for the treatment of severe vascular inflammatory diseases by inhibiting HMGB1 signaling pathway.

Ilimaquinone Induces the Apoptotic Cell Death of Cancer Cells by Reducing Pyruvate Dehydrogenase Kinase 1 Activity.

In cancer cells, aerobic glycolysis rather than oxidative phosphorylation (OxPhos) is generally preferred for the production of ATP. In many cancers, highly expressed pyruvate dehydrogenase kinase 1 (PDK1) reduces the activity of pyruvate dehydrogenase (PDH) by inducing the phosphorylation of its E1α subunit (PDHA1) and subsequently, shifts the energy metabolism from OxPhos to aerobic glycolysis. Thus, PDK1 has been regarded as a target for anticancer treatment. Here, we report that ilimaquinone (IQ), a sesquiterpene quinone isolated from the marine sponge Smenospongia cerebriformis, might be a novel PDK1 inhibitor. IQ decreased the cell viability of human and murine cancer cells, such as A549, DLD-1, RKO, and LLC cells. The phosphorylation of PDHA1, the substrate of PDK1, was reduced by IQ in the A549 cells. IQ decreased the levels of secretory lactate and increased oxygen consumption. The anticancer effect of IQ was markedly reduced in PDHA1-knockout cells. Computational simulation and biochemical assay revealed that IQ interfered with the ATP binding pocket of PDK1 without affecting the interaction of PDK1 and the E2 subunit of the PDH complex. In addition, similar to other pyruvate dehydrogenase kinase inhibitors, IQ induced the generation of mitochondrial reactive oxygen species (ROS) and depolarized the mitochondrial membrane potential in the A549 cells. The apoptotic cell death induced by IQ treatment was rescued in the presence of MitoTEMPO, a mitochondrial ROS inhibitor. In conclusion, we suggest that IQ might be a novel candidate for anticancer therapeutics that act via the inhibition of PDK1 activity.

Indole-associated predator-prey interactions between the nematode Caenorhabditis elegans and bacteria.

Indole is an intercellular and interkingdom signalling molecule found in diverse ecological niches. Caenorhabditis elegans is a bacterivorous nematode that lives in soil and compost environments and a useful model host for studies of host-microbe interactions. Although various bacteria and some plants produce large quantities of extracellular indole, little is known about the effects of indole, its derivatives, or of indole-producing bacteria on the behaviours of C. elegans or other animals. Here, they show that C. elegans senses and moves toward indole and several indole-producing bacteria, but avoids non-indole producing pathogenic bacteria. Furthermore, it was found indole-producing and non-indole-producing bacteria exert divergent effects on the egg-laying behaviour of C. elegans, and that various indole derivatives also modulate chemotaxis, egg-laying behaviour and the survival of C. elegans. In contrast, indole at high concentration can kill C. elegans, which in turn, has the ability to detoxify indole by oxidation and glucosylation. Transcriptional analysis showed indole markedly up-regulated the gene expressions of cytochrome P450s, UDP-glucuronosyltransferases and glutathione S-transferase, which well explained the modification of indole by C. elegans while indole down-regulated the expressions of collagen and F-box genes. Their findings suggest that indole and its derivatives are important signalling molecules during bacteria-nematode interactions.

Collismycin C from the Micronesian Marine Bacterium Streptomyces sp. MC025 Inhibits Staphylococcus aureus Biofilm Formation.

Biofilm formation plays a critical role in antimicrobial resistance in Staphylococcus aureus. Here, we investigated the potential of crude extracts of 79 Micronesian marine microorganisms to inhibit S. aureus biofilm formation. An extract of Streptomyces sp. MC025 inhibited S. aureus biofilm formation. Bioactivity-guided isolation led to the isolation of a series of 2,2'-bipyridines: collismycin B (1), collismycin C (2), SF2738 D (3), SF2738 F (4), pyrisulfoxin A (5), and pyrisulfoxin B (6). Among these bipyridines, collismycin C (2) was found to be the most effective inhibitor of biofilm formation by methicillin-sensitive S. aureus and methicillin-resistant S. aureus (MRSA), and this compound inhibited MRSA biofilm formation by more than 90% at a concentration of 50 µg/mL. The antibiofilm activity of collismycin C was speculated to be related to iron acquisition and the presence and position of the hydroxyl group of 2,2'-bipyridines.

Isolation of Indole Utilizing Bacteria Arthrobacter sp. and Alcaligenes sp. From Livestock Waste.

Indole is an interspecies and interkingdom signaling molecule widespread in different environmental compartment. Although multifaceted roles of indole in different biological systems have been established, little information is available on the microbial utilization of indole in the context of combating odor emissions from different types of waste. The present study was aimed at identifying novel bacteria capable of utilizing indole as the sole carbon and energy source. From the selective enrichment of swine waste and cattle feces, we identified Gram-positive and Gram-negative bacteria belonging to the genera Arthrobacter and Alcaligenes. Bacteria belonging to the genus Alcaligenes showed higher rates of indole utilization than Arthrobacter. Indole at 1.0 mM for growth was completely utilized by Alcaligenes sp. in 16 h. Both strains produced two intermediates, anthranilic acid and isatin, during aerobic indole metabolism. These isolates were also able to grow on several indole derivatives. Interestingly, an adaptive response in terms of a decrease in cell size was observed in both strains in the presence of indole. The present study will help to explain the degradation of indole by different bacteria and also the pathways through which it is catabolized. Furthermore, these novel bacterial isolates could be potentially useful for the in situ attenuation of odorant indole and its derivatives emitted from different types of livestock waste.

Vanillin Promotes Osteoblast Differentiation, Mineral Apposition, and Antioxidant Effects in Pre-Osteoblasts.

Antioxidant vanillin (4-hydroxy-3-methoxybenzaldehyde) is used as a flavoring in foods, beverages, and pharmaceuticals. Vanillin possesses various biological effects, such as antioxidant, anti-inflammatory, antibacterial, and anticancer properties. This study aimed to investigate the biological activities of vanillin purified from Adenophora triphylla var. japonica Hara on bone-forming processes. Vanillin treatment induced mineralization as a marker for mature osteoblasts, after stimulating alkaline phosphatase (ALP) staining and activity. The bone-forming processes of vanillin are mainly mediated by the upregulation of the bone morphogenetic protein 2 (BMP2), phospho-Smad1/5/8, and runt-related transcription factor 2 (RUNX2) pathway during the differentiation of osteogenic cells. Moreover, vanillin promoted osteoblast-mediated bone-forming phenotypes by inducing migration and F-actin polymerization. Furthermore, we validated that vanillin-mediated bone-forming processes were attenuated by noggin and DKK1. Finally, we demonstrated that vanillin-mediated antioxidant effects prevent the death of osteoblasts during bone-forming processes. Overall, vanillin has bone-forming properties through the BMP2-mediated biological mechanism, indicating it as a bone-protective compound for bone health and bone diseases such as periodontitis and osteoporosis.

Development of a surface plasmon resonance-based immunosensor for the rapid detection of cardiac troponin I.

The concentration of cardiac troponin I (cTnI) in blood is an important marker for heart muscle cell damage. A surface plasmon resonance (SPR)-based immunosensor was devised for the rapid and specific detection of cTnI. It was constructed by crosslinking a monoclonal antibody P-II-13, which was generated against a loop region (aa 84-94) of cTnI protein as an epitope peptide, onto a chemically modified thin gold film. The performance of the sensor was examined with respect to the SPR signal intensity versus cTnI concentration. The signal intensity was directly correlated with the cTnI concentration in the range of 0-160 µg/l. The sensor signal was saturated when the concentration of cTnI approached 660 µg/l with the SPR intensity of 172 RU. The lower detection limit of the sensor was 68 ng/l cTnI, which was comparable to ELISA-based commercial cTnI detection systems.

Antioxidant, Pancreatic Lipase Inhibitory, and Tyrosinase Inhibitory Activities of Extracts of the Invasive Plant Spartina anglica (Cord-Grass).

Since 2016, the invasive halophyte Spartina anglica has been colonizing mudflats along the western coast of South Korea. In order to minimize costs on S. anglica expansion management and waste-treatment of collected biomass, the potential application of the collected biomass of S. anglica was investigated. Ethanolic extracts and subfractions thereof (hexanes, methylene chloride, ethyl acetate, 1-butanol, and water-soluble) of the aerial and belowground parts of S. anglica showed free radical-scavenging [2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)], tyrosinase inhibitory, and pancreatic lipase inhibitory activities. An ethyl acetate fraction derived from aerial parts (EA-a) showed the most potent radical-scavenging and pancreatic lipase inhibitory activities, whereas tyrosinase inhibition was mainly observed in the methylene chloride soluble fractions (MC-bg) and other lipophilic fractions (ethyl acetate and hexanes layers) obtained from belowground parts. The major EA-a compound isolated and identified was 1,3-di-O-trans-feruloyl quinic acid (1) based on spectroscopic analysis, whereas the two major MC-bg compounds were identified as p-hydroxybenzaldehyde (2) and N-trans-feruloyltyramine (3). Compounds 1 and 3 scavenged both DPPH and ABTS radicals, whereas 1 and 2 inhibited pancreatic lipase activity. These results indicate that extracts and fractions of S. anglica have antioxidant, anti-obesity, and whitening properties with potential pharmaceutical, cosmeceutical, and functional food applications.

Suppressive functions of collismycin C in TGFBIp-mediated septic responses.

Transforming growth factor ß-induced protein (TGFBIp) is an extracellular matrix protein; its expression by several cell types is greatly increased by TGF-ß. TGFBIp is released by primary human umbilical vein endothelial cells (HUVECs) and functions as a mediator of experimental sepsis. 2,2'-Bipyridine-containing natural products are generally accepted to have antimicrobial, cytotoxic and anti-inflammatory properties. We hypothesized that a 2,2'-bipyridine containing natural product, collismycin C, could reduce TGFBIp-mediated severe inflammatory responses in human endothelial cells and mice. Here we investigated the effects and underlying mechanisms of collismycin C against TGFBIp-mediated septic responses. Collismycin C effectively inhibited lipopolysaccharide-induced release of TGFBIp and suppressed TGFBIp-mediated septic responses. In addition, collismycin C suppressed TGFBIp-induced sepsis lethality and pulmonary injury. This suppression of TGFBIp-mediated and CLP-induced septic responses indicates that collismycin C is a potential therapeutic agent for various severe vascular inflammatory diseases, with inhibition of the TGFBIp signaling pathway as the mechanism of action.

Inhibitory effects of collismycin C and pyrisulfoxin A on particulate matter-induced pulmonary injury.

BACKGROUND: Inhalation of fine particulate matter (PM2.5) is associated with elevated pulmonary injury caused by the loss of vascular barrier integrity. Marine microbial natural products isolated from microbial culture broths were screened for pulmonary protective effects against PM2.5. Two 2,2'-bipyridine compounds isolated from a red alga-associated Streptomyces sp. MC025-collismycin C (2) and pyrisulfoxin A (5)-were found to inhibit PM2.5-mediated vascular barrier disruption. PURPOSE: To confirm the inhibitory effects of collismycin C and pyrisulfoxin A on PM2.5-induced pulmonary injury STUDY DESIGN: In this study, we investigated the beneficial effects of collismycin C and pyrisulfoxin A on PM-induced lung endothelial cell (EC) barrier disruption and pulmonary inflammation. METHODS: Permeability, leukocyte migration, proinflammatory protein activation, reactive oxygen species (ROS) generation, and histology were evaluated in PM2.5-treated ECs and mice. RESULTS: Collismycin C and pyrisulfoxin A significantly scavenged PM2.5-induced ROS and inhibited the ROS-induced activation of p38 mitogen-activated protein kinase as well as activated Akt, which helped in maintaining endothelial integrity, in purified pulmonary endothelial cells. Furthermore, collismycin C and pyrisulfoxin A reduced vascular protein leakage, leukocyte infiltration, and proinflammatory cytokine release in the bronchoalveolar lavage fluid of PM-treated mice. CONCLUSION: These data suggested that collismycin C and pyrisulfoxin A might exert protective effects on PM-induced inflammatory lung injury and vascular hyperpermeability.

Cinnamomulactone, a new butyrolactone from the twigs of Cinnamomum cassia and its inhibitory activity of matrix metalloproteinases.

Cinnamomum cassia (Lauraceae) has long been used as one of the most frequently used traditional oriental medicines for the treatment of gastritis, diabetes, blood circulation disturbance and inflammatory diseases. Cinnamomulactone (1), a new butyrolactone was isolated from the twigs of C. cassia together with nine known compounds, coumarin (2), trans-cinnamic acid (3), cinnamaldehyde (4), 2-hydroxycinnamaldehyde (5), 2-methoxycinnamaldehyde (6), 2-hydroxy-cinnamyl alcohol (7), benzoic acid (8), (+)-syringaresinol (9) and phenethyl (E)-3-[4-methoxyphenyl]-2-propenoate (10). The planar structure of 1 was elucidated on the basis of spectroscopic data analysis and its configurations were determined by coupling constant (3 J HH) analysis and a comparison with specific rotation data of related compounds on the literatures. The structures of known compounds were confirmed by the comparison of their spectroscopic data to the reported values. Compound 10 was isolated for the first time from this plant. Compounds 1, 2, 4, and 9 showed inhibitory activity against matrix metalloproteinases (MMPs) gene expression. Among them, compound 1 has been revealed to suppress the gene expression of MMP-3 and interleukin (IL)-1ß as well as MMP-1 in tumor necrosis factor (TNF)-α stimulated rheumatoid arthritis synovial fibroblasts.

Isolation of Bacteria Associated with the King Oyster Mushroom, Pleurotus eryngii.

Eight distinct bacteria were isolated form diseased mycelia of the edible mushroom, Pleurotus eryngii. 16S rDNA sequence analysis showed that the isolates belonged to a variety of bacterial genera including Bacillus (LBS5), Enterobacter (LBS1), Sphingomonas (LBS8 and LBS10), Staphylococcus (LBS3, LBS4 and LBS9) and Moraxella (LBS6). Among them, 4 bacterial isolates including LBS1, LBS4, LBS5, and LBS9 evidenced growth inhibitory activity on the mushroom mycelia. The inhibitory activity on the growth of the mushroom fruiting bodies was evaluated by the treatment of the bacterial culture broth or the heat-treated cell-free supernatant of the broth. The treatment of the culture broths or the cell-free supernatants of LBS4 or LBS9 completely inhibited the formation of the fruiting body, thereby suggesting that the inhibitory agent is a heat-stable compound. In the case of LBS5, only the bacterial cell-containing culture broth was capable of inhibiting the formation of the fruiting body, whereas the cell-free supernatant did not, which suggests that an inhibitory agent generated by LBS5 is a protein or a heat-labile chemical compound, potentially a fungal cell wall-degrading enzyme. The culture broth of LBS1 was not inhibitory. However, its cell-free supernatant was capable of inhibiting the formation of fruiting bodies. This indicates that LBS1 may produce an inhibitory heat-stable chemical compound which is readily degraded by its own secreted enzyme.