Effects of polystyrene microplastics on the metabolic level of Pseudomonas aeruginosa.

Given the widespread presence of Pseudomonas aeruginosa in water and its threat to human health, the metabolic changes in Pseudomonas aeruginosa when exposed to polystyrene microplastics (PS-MPs) exposure were studied, focusing on molecular level. Through non-targeted metabolomics, a total of 64 differential metabolites were screened out under positive ion mode and 44 under negative ion mode. The content of bacterial metabolites changed significantly, primarily involving lipids, nucleotides, amino acids, and organic acids. Heightened intracellular oxidative damage led to a decrease in lipid molecules and nucleotide-related metabolites. The down-regulation of amino acid metabolites, such as L-Glutamic and L-Proline, highlighted disruptions in cellular energy metabolism and the impaired ability to synthesize proteins as a defense against oxidation. The impact of PS-MPs on organic acid metabolism was evident in the inhibition of pyruvate and citrate, thereby disrupting the cells' normal participation in energy cycles. The integration of Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that PS-MPs mainly caused changes in metabolic pathways, including ABC transporters, Aminoacyl-tRNA biosynthesis, Purine metabolism, Glycerophospholipid metabolism and TCA cycle in Pseudomonas aeruginosa. Most of the differential metabolites enriched in these pathways were down-regulated, demonstrating that PS-MPs hindered the expression of metabolic pathways, ultimately impairing the ability of cells to synthesize proteins, DNA, and RNA. This disruption affected cell proliferation and information transduction, thus hampering energy circulation and inhibiting cell growth. Findings of this study supplemented the toxic effects of microplastics and the defense mechanisms of microorganisms, in turn safeguarding drinking water safety and human health.

[Influence of Polystyrene Microplastics on the Formation and Structural Change of Pseudomonas aeruginosa Biofilm].

Microplastic pollution in the water environment is becoming increasingly serious, impacting the growth and development of aquatic organisms. There are limited studies on the mechanisms of microplastic effects on biofilm formation. Therefore, in this study, the effects of polystyrene microplastics (PS-MPs) were investigated on the biofilm formation and development of Pseudomonas aeruginosa. Different concentrations and particle sizes of PS-MPs were selected for exposure tests to explore the effects on biofilm biomass, oxidative stress levels, biofilm structure, and population sensing system. The results showed that PS-MPs induced severe oxidative stress and inhibited biofilm formation and development, and the smaller the particle size, the stronger the inhibitory effect was. The inhibition effect was 0.1 µm>0.5 µm≈1 µm>5 µm. PS-MPs caused severe physical damage through contact with bacteria. The thickness of the biofilm was significantly reduced, damaging the structural stability. The bacteria in the biofilm secreted extracellular polymers to resist the stress of PS-MPs. Meanwhile, PS-MPs interfered with the QS system of P. aeruginosa; down-regulated the expression levels of key genes lasI, lasR, rhlI, and rhlR; inhibited the synthesis and secretion of signal molecules and related virulence factors; and ultimately affected the formation and structural stability of biofilms.

Artepillin C Time-Dependently Alleviates Metabolic Syndrome in Obese Mice by Regulating CREB/CRTC2-BMAL1 Signaling.

Artepillin C (APC), a cAMP-response element-binding (CREB)/CREB regulated transcription coactivator 2 (CRTC2) inhibitor isolated from Brazilian green propolis, can ameliorate metabolic syndrome in obese mice. Because the sensitivity and responsiveness of the body to the drug depend on the time of day and the circadian clock alignment, the optimal administration time of APC for desired efficacy in treating metabolic syndrome remains unclear. In this study, APC (20 mg/kg) or the vehicle was intraperitoneally injected into obese mice once daily for one or three weeks. The results of the insulin tolerance test, pyruvate tolerance test, and histological and biochemical assays showed that APC could improve whole-body glucose homeostasis and decrease hepatic lipid synthesis following a circadian rhythm. Further exploration of the underlying mechanism revealed that APC may disturb the diurnal oscillations of the expression of brain and muscle ARNT-like protein (BMAL1) in primary hepatocytes and the livers of the study subjects. Moreover, APC could inhibit hepatic BMAL1 expression by blocking the CREB/CRTC2 transcription complex. BMAL1 overexpression in primary hepatocytes or the livers of db/db mice antagonized the inhibitory effect of APC on hepatic lipid metabolism. In conclusion, the chronotherapy of APC may relieve metabolic syndrome in obese mice, and the mechanism behind APC-mediated time-of-day effects on metabolic syndrome were unveiled, thereby providing a foundation for optimized APC treatment from a mechanistic perspective.

[Short needling for knee osteoarthritis with blood stasis obstruction and its effect on serum inflammatory factors].

OBJECTIVE: To compare the clinical efficacy and its effect on serum levels of tumor necrosis factor α(TNF-α), interleukin 1ß(IL-1ß), interleukin 6 (IL-6) and prostaglandin E2 (PGE2) between short needling (close-to-bone needling) and conventional acupuncture for knee osteoarthritis (KOA) with blood stasis obstruction. METHODS: A total of 68 KOA patients with blood stasis obstruction were randomized into a short needling group (34 cases, 3 cases dropped off) and a conventional acupuncture group (34 cases, 3 cases dropped off). The same acupoints (Dubi [ST 35], Neixiyan [EX-LE 4], Binzhong [Extra], Liangqiu [ST 34], etc. on the affected side) were selected in the two groups. In the short needling group, short needling technique was adopted, the needles were slowly inserted and the needle bodies were shaken, thus gradually penetrated to the bone. In the conventional acupuncture group, conventional acupuncture was adopted, the needles were penetrated to the muscle. After qi-arrival, Dubi (ST 35) and Neixiyan (EX-LE 4), Zusanli (ST 36) and Liangqiu (ST 34) were connected with CMNS6-1 electronic acupuncture instrument, with disperse-dense wave, 2 Hz/10 Hz in frequency, the current intensity was based on patients' feeling, the needles were retained for 30 min, at the same time, the knee joint was irradiated for 30 min with a special electromagnetic wave apparatus in the two groups. Once every other day, 3 times a week for 4 weeks. Before and after treatment, the Western Ontario and McMaster Universities osteoarthritis index (WOMAC) score, knee joint pain visual analogue scale (VAS) score, inflammatory response related indexes (serum TNF-a, IL-1ß, IL-6 and PGE2) and knee joint ultrasound were observed，and the clinical effect was evaluated in the two groups. RESULTS: After treatment，the pain, stiffness, function scores and total scores of WOMAC were decreased as compared with those before treatment in the two groups (P<0.05), except for the pain score, the changes of above scores in the short needling group were greater than the conventional acupuncture group (P<0.05). After treatment, the VAS scores, serum levels of TNF-a, IL-1ß, IL-6, PGE2 and knee joint synovium thickness, intra-articular effusion were decreased as compared with those before treatment in the two groups (P<0.05), the levels of TNF-a, IL-1ß, IL-6 in the short needling group were lower than the conventional acupuncture group (P<0.05). The total effective rate in the short needling group was 87.1% (27/31), which was superior to 83.9% (26/31) in the conventional acupuncture group (P<0.05). CONCLUSION: Short needling could improve the knee joint function, relieve the pain and inflammatory response, improve the knee joint synovium inflammatory response, reduce the knee joint intra-articular effusion for KOA patients, its effect is better than conventional acupuncture.

Deposition of polystyrene microplastics on bare or biofilm-coated silica analysed via QCM-D.

The mobility of microplastics (MPs) in aqueous media is closely related to their environmental risk. The naturally occurring silica substrate surface in the aquatic environment is easily colonized by microorganisms and forms a biofilm, which may affect the migration and distribution of MPs. Herein, a typical MP, polystyrene (PS), and Pseudomonas fluorescens (P. fluorescens) biofilms were selected to study the deposition and release of pristine or ultraviolet (UV)-aged PS MPs on silica and biofilms under different ionic strengths using a quartz crystal microbalance dissipation (QCM-D) system. Statistical analyses of the deposition experiments revealed a significant impact of P. fluorescens biofilms on deposition (p = 0.0042). The deposition rate of weathered MPs on the biofilms was 4.0 ± 0.1 to 16.3 ± 0.6 times that on silica. A release experiment revealed that the biofilm reduced the release fraction (fr) of weathered MPs by 34.5 ± 0.3 % compared to bare silica. In addition, the UV-ageing treatment reduced the deposition mass of MPs on the surface of silica by 27.6 ± 0.21 % compared to pristine microspheres. The analysis of the deposition mechanism revealed that the promotion and inhibition of biofilm or UV-ageing treatment on the deposition of microspheres could be attributed to the non-Derjaguin-Landau-Verwey-Overbeek (DLVO) force and the decreased electrostatic repulsion or the increased hydration repulsion, respectively.

A propolis-derived small molecule ameliorates metabolic syndrome in obese mice by targeting the CREB/CRTC2 transcriptional complex.

The molecular targets and mechanisms of propolis ameliorating metabolic syndrome are not fully understood. Here, we report that Brazilian green propolis reduces fasting blood glucose levels in obese mice by disrupting the formation of CREB/CRTC2 transcriptional complex, a key regulator of hepatic gluconeogenesis. Using a mammalian two-hybrid system based on CREB-CRTC2, we identify artepillin C (APC) from propolis as an inhibitor of CREB-CRTC2 interaction. Without apparent toxicity, APC protects mice from high fat diet-induced obesity, decreases fasting glucose levels, enhances insulin sensitivity and reduces lipid levels in the serum and liver by suppressing CREB/CRTC2-mediated both gluconeogenic and SREBP transcriptions. To develop more potential drugs from APC, we designed and found a novel compound, A57 that exhibits higher inhibitory activity on CREB-CRTC2 association and better capability of improving insulin sensitivity in obese animals, as compared with APC. In this work, our results indicate that CREB/CRTC2 is a suitable target for developing anti-metabolic syndrome drugs.

[Internal circadian clock and liver metabolism].

Circadian clock is an internal autonomous time-keeping system, including central clocks located in the suprachiasmatic nucleus (SCN) and peripheral clocks. The molecular circadian clock consists of a set of interlocking transcriptional-translational feedback loops that take the clock-controlled genes 24 h to oscillate. The core mechanism of molecular circadian clock is that CLOCK/BMAL1 dimer activates the transcription of cryptochromes (CRYs) and Periods (PERs), which act as transcriptional repressors of further CLOCK/BMAL1-mediated transcription. In addition to this basic clock, there is an additional sub-loop of REV-ERBα and RORα regulating the transcription of BMAL1. Approximately 80% protein-coding genes demonstrate significant rhythmicity. The earth rotation is responsible for the generation of the daily circadian rhythms. To coordinate metabolic balance and energy availability, almost all organisms adapt to the rhythm. Studies have shown that circadian clock integrating with metabolic homeostasis increases the efficiency of energy usage and coordinates with different organs in order to adapt to internal physiology and external environment soon. As the central organ of metabolism, the liver performs various physiological activities nearly all controlled by the circadian clock. There are multiple interactive regulation mechanisms between the circadian clock and the regulation of liver metabolism. The misalignment of metabolism with tissue circadian is identified as a high-risk factor of metabolic diseases. This article reviews the recent studies on circadian physiological regulation of liver glucose, lipid and protein metabolism and emphasizes oscillation of mitochondrial function. We also take an outlook for new methods and application of circadian clock research in the future.

Myristoylation-mediated phase separation of EZH2 compartmentalizes STAT3 to promote lung cancer growth.

N-myristoylation is a crucial signaling and pathogenic modification process that confers hydrophobicity to cytosolic proteins. Although different large-scale approaches have been applied, a large proportion of myristoylated proteins remain to be identified. EZH2 is overexpressed in lung cancer cells and exerts oncogenic effects via its intrinsic methyltransferase activity. Using a well-established click chemistry approach, we found that EZH2 can be modified by myristoylation at its N-terminal glycine in lung cancer cells. Hydrophobic interaction is one of the main forces driving or stabilizing liquid-liquid phase separation (LLPS), raising the possibility that myristoylation can modulate LLPS by mediating hydrophobic interactions. Indeed, myristoylation facilitates EZH2 to form phase-separated liquid droplets in lung cancer cells and in vitro. Furthermore, we provide evidence that myristoylation-mediated LLPS of EZH2 compartmentalizes its non-canonical substrate, STAT3, and activates STAT3 signaling, ultimately resulting in accelerated lung cancer cell growth. Thus, targeting EZH2 myristoylation may have significant therapeutic efficacy in the treatment of lung cancer. Altogether, these observations not only extend the list of myristoylated proteins, but also indicate that hydrophobic lipidation may serve as a novel incentive to induce or maintain LLPS.