Platycodon grandiflorus polysaccharide inhibits the inflammatory response of 3D4/21 cells infected with PCV2.

Porcine circovirus type 2 (PCV2) infection cause multi-systemic inflammation in pigs. Platycodon grandiflorus polysaccharide (PGPSt) has been reported to have the effects of immune regulation and disease resistance. Nevertheless, the role and mechanism of PGPSt in the inflammatory response of 3D4/21 cells induced by PCV2 infection remain unclear. The present study aims to investigate effects of PGPSt on inflammatory response and its possible underlying mechanisms in vitro models. Cells were treated with PCV2 for 36 h to construct a cell inflammation model. The 3D4/21 cell lines were pretreated with or without PGPSt, and the changes of inflammation-related markers and the signaling pathway were detected by CCK-8, ELISA, qPCR and Western blot. The results showed that PGPSt was non-toxic to cells and protected PCV2-infected cells from inflammatory damage. PGPSt could significantly inhibit the high acetylation of histone H3 (AcH3) and histone H4 (AcH4), down-regulate HAT and up-regulate HDAC activity, and reduce the expression of pro-inflammatory enzymes iNOS and COX-2 proteins levels. Then the levels of IL-1ß, IL-6 and TNF-α were significantly inhibited, and the level of IL-10 was promoted. We also observed that PGPSt inhibited the phosphorylation of p65, p38 and Erk1/2, which subsequently inhibited nuclear translocation of NF-κB p65 to express pro-inflammatory factors. In conclusion, PGPSt can reduce the inflammatory response by regulating histone acetylation, reducing the release of inflammatory factors, reducing the expression of pro-inflammatory enzymes, and inhibiting the activation of NF-κB and MAPKs signaling pathways. This suggests that PGPSt had an anti-inflammatory effect on the inflammatory response caused by PCV2 infection, which provided theoretical data support for the research.

First Report of Colletotrichum siamense Causing Fruit Anthracnose on Pomegranate (Punica granatum) in China.

As a native crop in central Asia, pomegranate (Punica granatum L.) has been cultivated in China for more than 2000 years (Yuan et al. 2007). In August 2022, typical symptoms of anthracnose were observed on pomegranate fruitlets in the main cultivation area (34°22'36″N, 109°15'58″E) in Shaanxi Province, China. The disease incidence was approximately 10 to 15% in the field. The initial symptoms were slightly small, light, dark, sunken lesions with irregular, circular shapes. As the disease progressed, the necrotic lesions gradually expanded and merged, eventually leading to the abscission of fruits (Figure 1, A). The symptomatic lesion samples of the pomegranate were sterilized for 1.5 min in 75% ethanol and 2 min in 1% NaClO and rinsed for 2 min in sterile water three times. The sterilized samples were dried on sterile filter paper and placed on potato dextrose agar (PDA) media at 25 ℃ for 5 days. The mycelia of the isolate were white, cottony, and diffuse (Figure 1, B and C). The conidia were single-celled, smooth, aseptate, and cylindrical with slightly rounded ends, measured 13.5 to 17.5 µm long and 3.5 to 6.5 µm wide (mean 16.0 × 4.5 µm, n = 50) (Figure 1, D). These morphological characteristics were identical to those of Colletotrichum siamense (Weir et al. 2012; Cannon et al. 2012; Zhuo et al. 2022). For accurate molecular characterization of the fungus, genomic DNA was extracted from the hyphae of the two isolates using microorganism lysis buffer (Takara, Japan). The internal transcribed spacer (ITS), calmodulin (CAL), actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and beta-tubulin (TUB2) regions were amplified and sequenced. All the sequences were submitted to GenBank with accession numbers OQ832556 (ITS), OQ848589 (GAPDH), OQ848590 (ACT), OQ848591 (CAL), and OQ986593 (TUB2). The isolates showed 99 to 100% identity with sequences of Colletotrichum siamense (100% with GAPDH, ACT, CAL, and TUB2; 99.81% with ITS). The morphology of the strain was studied, and multilocus (ITS, GAPDH, ACT, CAL, and TUB2) phylogenetic analysis was performed (Figure 2). Therefore, the causal pathogen was identified as C. siamense based on the results of morphological and molecular analyses. Pathogenicity assays were performed on pomegranate (cv. Lishanhong) fruits. A conidial suspension (1×106 conidia/mL) was sprayed onto 10 unwounded fruits to inoculate them as infected samples, and the controls were inoculated with a sterile water suspension. All the samples were maintained in an artificial climate box at 25 ± 2 ℃ with 70% relative humidity, and the photoperiod was set as 12:12 light:dark. After 5 to 7 days, anthracnose symptoms developed on the surface of the inoculated fruit, whereas the control fruits remained healthy. The diseased fruits exhibited brown necrotic lesions, whereas the upper surfaces of the control fruits remained asymptomatic. The morphological and molecular characteristics of the reisolated pathogen were identical to those of the original fungus isolated from the natural fruit. C. siamense has been reported to cause anthracnose in the southeastern United States (Xavier et al. 2019). The pathogen causing anthracnose on pomegranates has been reported to be Colletotrichum fructicola in China (Hu et al. 2023). To our knowledge, this is the first report of anthracnose on pomegranate fruits caused by C. siamense in China. This disease can directly affect the quality and yield of the fruit. Thus, information about the characteristics of this disease could provide a theoretical basis for its prevention and control.

Melatonin Attenuates H2O2-Induced Oxidative Injury by Upregulating LncRNA NEAT1 in HT22 Hippocampal Cells.

More research is required to understand how melatonin protects neurons. The study aimed to find out if and how long non-coding RNA (lncRNA) contributes to melatonin's ability to defend the hippocampus from H2O2-induced oxidative injury. LncRNAs related to oxidative injury were predicted by bioinformatics methods. Mouse hippocampus-derived neuronal HT22 cells were treated with H2O2 with or without melatonin. Viability and apoptosis were detected by Cell Counting Kit-8 and Hoechst33258. RNA and protein levels were measured by quantitative real-time PCR, Western blot, and immunofluorescence. Bioinformatics predicted that 38 lncRNAs were associated with oxidative injury in mouse neurons. LncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) was related to H2O2-induced oxidative injury and up-regulated by melatonin in HT22 cells. The knockdown of NEAT1 exacerbated H2O2-induced oxidative injury, weakened the moderating effect of melatonin, and abolished the increasing effect of melatonin on the mRNA and protein level of Slc38a2. Taken together, melatonin attenuates H2O2-induced oxidative injury by upregulating lncRNA NEAT1, which is essential for melatonin stabilizing the mRNA and protein level of Slc38a2 for the survival of HT22 cells. The research may assist in the treatment of oxidative injury-induced hippocampal degeneration associated with aging using melatonin and its target lncRNA NEAT1.

Transient Receptor Potential Channel, Vanilloid 5, Induces Chondrocyte Apoptosis in a Rat Osteoarthritis Model Through the Mediation of Ca2+ Influx.

BACKGROUND/AIMS: Chondrocyte apoptosis is the most common pathological feature in cartilage in osteoarthritis (OA). Transient receptor potential channel vanilloid 5 (TRPV5) is important in regulating calcium ion (Ca2+) influx. Accumulating evidences suggest that Ca2+ is a major intracellular second messenger that can trigger cell apoptosis. Therefore, we investigate the potential role of TRPV5 in mediating Ca2+ influx to promote chondrocyte apoptosis in OA. METHODS: The monoiodoacetic acid (MIA)-induced rat OA model was assessed by macroscopic and radiographic analyses. Calmodulin protein immunolocalization was detected by immunohistochemistry. The mRNA and protein level of TRPV5, calmodulin and cleaved caspase-8 in articular cartilage were assessed by real time polymerase chain reaction and western blotting. Primary chondrocytes were isolated and cultured in vitro. TRPV5 small interfering RNA was used to silence TRPV5 in chondrocytes. Then, calmodulin and cleaved caspase-8 were immunolocalized by immunofluorescence in chondrocyte. Fluo-4AM staining was used to assess intracellular Ca2+ to reflect TRPV5 function of mediation Ca2+ influx. Annexin V-fluorescein isothiocyanatepropidium iodide flow cytometric analysis was performed to determine chondrocytes apoptosis. Western blotting techniques were used to measure the apoptosis-related proteins in chondrocyte level. RESULTS: Here, we reported TRPV5 was up-regulated in MIA-induced OA articular cartilage. Ruthenium red (a TRPV5 inhibitor) can relieve progression of joint destruction in vivo which promoted us to demonstrate the effect of TRPV5 in OA. We found that TRPV5 had a specific role in mediating extracellular Ca2+ influx leading to chondrocytes apoptosis in vitro. The apoptotic effect was inhibited even reversed by silencing TRPV5. Furthermore, we found that the increase Ca2+ influx triggered apoptosis by up-regulating the protein of death-associated protein, FAS-associated death domain, cleaved caspase-8, cleaved caspase-3, cleaved caspase-6, and cleaved caspase-7, and the up-regulated proteins were abolished by silencing TRPV5 or 1, 2-bis-(o-Aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, tetraacetoxymethyl ester (a Ca2+ chelating agent). CONCLUSION: The up-regulated TRPV5 could used be as an initiating factor that induces extrinsic chondrocyte apoptosis via the mediation of Ca2+ influx. These findings suggested TRPV5 could be an intriguing mediator for drug target in OA.

Machine learning-based identification and immune characterization of ferroptosis-related molecular clusters in osteoarthritis and validation.

Osteoarthritis (OA), a degenerative joint disease, involves synovial inflammation, subchondral bone erosion, and cartilage degeneration. Ferroptosis, a regulated non-apoptotic programmed cell death, is associated with various diseases. This study investigates ferroptosis-related molecular subtypes in OA to comprehend underlying mechanisms. The Gene Expression Omnibus datasets GSE206848, GSE55457, GSE55235, GSE77298 and GSE82107 were used utilized. Unsupervised clustering identified the ferroptosis-related gene (FRG) subtypes, and their immune characteristics were assessed. FRG signatures were derived using LASSO and SVM-RFE algorithms, forming models to evaluate OA's ferroptosis-related immune features. Three FRG clusters were found to be immunologically heterogeneous, with cluster 1 displaying robust immune response. Models identified nine key signature genes via algorithms, demonstrating strong diagnostic and prognostic performance. Finally, qRT-PCR and Western blot validated these genes, offering consistent results. In addition, some of these genes may have implications as new therapeutic targets and can be used to guide clinical applications.

Flame Retardancy of Nylon 6 Fibers: A Review.

As synthetic fibers with superior performances, nylon 6 fibers are widely used in many fields. Due to the potential fire hazard caused by flammability, the study of the flame retardancy of nylon 6 fibers has been attracting more and more attention. The review has summarized the present research status of flame-retarded nylon 6 fibers from three aspects: intrinsic flame-retarded nylon 6, nylon 6 composites, and surface strategies of nylon 6 fibers/fabrics. The current main focus is still how to balance the application performances, flame retardancy, and production cost. Moreover, melt dripping during combustion remains a key challenge for nylon 6 fibers, and the further developing trend is to study novel flame retardants and new flame-retardancy technologies for nylon 6 fibers.

Analysis of the shape characteristics and nutritional components of Akebia trifoliata in Qinba Mountains.

Akebia trifoliata (A. trifoliata) is a widely distributed wild vine that has attracted much attention in recent years due to the edible fruit of food and medicinal value. In this paper, the fruits of A. trifoliata, which are derived from Qinling Mountains (12 genotypes) and Bashan Mountains (4 genotypes) and have been artificially domesticated and cultivated for many years, are taken as the research object to study the fruit characteristics and pulp components of 16 genotypes of A. trifoliata. The results show that the pulp of the 16 genotypes contain a variety of nutrients, among which the average contents of total sugar, total acid, vitamin C, soluble solids and starch are 14.68g/100g, 0.14g/100g, 26.40mg/100g, 17.95% and 5.29g/100g. The fruit contains 17 amino acids, including 7 essential amino acids and 4 organic acids. The latter refers to malic acid, lactic acid, citric acid and fumaric acid, the average contents of which are 1.03g/kg, 3.38g/kg, 0.33g/kg and 0.0149g/kg. Besides, 8 mineral elements in the fruit include 4 macro elements and 4 micro elements. The average contents of the former are potassium (1.83g/kg), calcium (0.23g/kg), phosphorus (0.28g/kg) and magnesium (0.21g/kg), and the average contents of the latter are iron (2.29mg/kg), zinc (2.23mg/kg), copper (1.37mg/kg) and manganese (5.52mg/kg). During the ripening process of A. trifoliata fruit (using HY-9 as the material), the main nutrients in the pulp such as total sugar, soluble solids, starch, amino acids and various mineral elements reach the maximum in stage 3, indicating that stage 3 is the best edible period of A. trifoliata fruit. Through the assignment analysis and comprehensive evaluation of 9 quality indicators (3 apparent characters and 6 main chemical components) of the fruits of the 16 A. trifoliata genotypes from Qinba Mountains, HY-1, HY-2 and HY-9 were finally screened out as the three superior genotypes. This study aims to provide reference for the development and utilization of A. trifoliata wild germplasm resources and the selection of new varieties.

The surface morphology of Platycodon grandiflorus polysaccharide and its anti-apoptotic effect by targeting autophagy.

BACKGROUND: Fumonisin B1 is categorised as possible carcinogenic to humans which commonly contaminate maize and maize-based products worldwide, FB1, like other environmental pollutants, may activate apoptosis, autophagy, the inflammatory response and oxidative stress. Platycodon grandiflorus polysaccharide (PGPSt) is prepared from a traditional herbal medicine in Asia with tremendous pharmacological activities. However, whether PGPSt could relieve FB1-induced apoptosis has not been elucidated. The study aimed to evaluate the surface morphology of PGPSt and its protective effect on fumonisin B1-induced apoptosis. METHODS: The surface morphology of PGPSt was evaluated by SEM and AFM. Expressions of proteins involved in autophagy and apoptosis were detected by western blot analysis. Western blot, transient transfection, JC-1 and Annexin V-FITC/PI staining, CCK8, Live-cell imaging and autophagy inhibitor were used to observe the effect and explore the mechanism of PGPSt on FB1-induced apoptosis of 3D4/21 cells. RESULTS: PGPSt had triple helix conformation, and had the characteristics of compact, polyporous and agglomerated morphology. PGPSt promoted the expression of LC3-II and Beclin1, reduced the expression of p62, and significantly activated autophagy. PGPSt inhibited the Akt/mTOR signaling pathway at 24 h. Besides, PGPSt increased the expression of Bcl-2 and decreased the expression of Cleaved Caspase-3. PGPSt-mediated autophagy was inhibited by 3-MA, accompanied by the upregulation of Caspase-3 and Cleaved Caspase-3, suggesting that enhanced autophagy inhibited apoptosis. CONCLUSION: PGPSt can activate autophagy, which in turn protects FB1-induced apoptosis. Targeting autophagy may provide a new way to improve the health of humans or animals in FB1 contaminated areas.

Melatonin Protects HT22 Hippocampal Cells from H2O2-induced Injury by Increasing Beclin1 and Atg Protein Levels to Activate Autophagy.

BACKGROUND: The aging of hippocampal neurons leads to a substantial decline in memory formation, storage and processing. The neuroprotective effect of melatonin has been confirmed, however, its protective mechanism remains unclear. OBJECTIVE: In this study, mouse hippocampus-derived neuronal HT22 cells were used to investigate whether melatonin protects the hippocampus from hydrogen peroxide (H2O2)-induced injury by regulating autophagy. METHODS: Rapamycin (an activator of autophagy) and 3-methyladenine (3MA, an inhibitor of autophagy) were used to induce or inhibit autophagy, respectively. HT22 cells were treated with 200 µM H2O2 in the presence or absence of 50 µM melatonin. Cell counting kit 8 (CCK-8), ß-galactosidase and Hoechst staining were used to measure the viability, aging and apoptosis of cells, respectively. Western blot analysis was used to detect the levels of autophagy-related proteins. RESULTS: The activation of autophagy by rapamycin alleviated H2O2-induced oxidative injury, as evidenced by morphological changes and decreased viability, while the inhibition of autophagy by 3MA exacerbated H2O2- induced injury. The inhibitory effect of melatonin on H2O2-induced injury was similar to that of rapamycin. Melatonin also alleviated H2O2-induced aging and apoptosis. Melatonin activated autophagy in the presence or absence of H2O2, as evidenced by an increased Lc3b 14/16 kd ratio and a decreased P62 level. In addition, H2O2 decreased the levels of Beclin1 and Atg5/12/16, which were reversed by rapamycin or melatonin. The effects of melatonin on H2O2-induced injury, autophagy and protein expressions were effectively reversed by 3MA. CONCLUSION: In conclusion, these results demonstrate that melatonin protects HT22 hippocampal neurons from H2O2-induced injury by increasing the levels of the Beclin1 and Atg proteins to activate autophagy.

Influence of modified atmosphere treatment on post-harvest reactive oxygen metabolism of pomegranate peels.

Modified atmosphere storage can regulate the reactive oxygen metabolism of fruits and vegetables, reduce the accumulation of hazardous free radicals, and mitigate the peroxidation degree of fruit membrane lipids. In this study, different gas matching ratios were adopted for the modified atmosphere treatment of pomegranate fruits. Up to 120 d of storage, compared with the control treatment, the H2O2 and malonaldehyde (MDA) contents in treatment 2 decreased by 8.88% and 18.28%, respectively, when the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbic acid peroxidase (APX) in treatment 2 increased by 21.44%, 117.38% and 114.95%, the ascorbic acid (ASA) and glutathione (GSH) contents in treatment 2 also increased by 116.83% and 50%, these results showed that treatment 2 (6.0% O2, 6.0% CO2) could effectively regulate various indexes of the reactive oxygen metabolism of pomegranate peels, maintain the normal physiological actions of the fruits, and postpone the ripening and senescence of histocytes. Under treatment 4 (10.0% O2, 10.0% CO2), H2O2 contents in the pomegranate peel significantly increased, and the activities of SOD, CAT and APX significantly reduced. ASA and GSH were degraded, the MDA content abruptly increased, the membrane lipid peroxidation accelerated, and the cytomembrane structure was destroyed.

Decreased ovarian function and autophagy gene methylation in aging rats.

BACKGROUND: Degeneration of ovarian function is an obvious feature of female aging. In addition, studies have shown that autophagy decreases with age, and DNA methylation is a hallmark epigenetic pattern during aging. However, it is not clear whether the expression and DNA methylation of autophagy genes are involved in the declines in ovarian function that occur during aging. RESULTS: Three groups of rats were used: 6-month-old (6 M) rats, 12-month-old (12 M) rats and 24-month-old (24 M) rats. Serum E2 levels and the mRNA and protein expression levels of Atg5, Atg12, Atg16L, Beclin1 and Lc3B were significantly decreased in aged rats. In addition, the methylation levels of the Atg5 gene were significantly increased in aged rats. The expression of the Dnmt1 and Dnmt2 genes decreased with aging; however, the expression of the Dnmt3A and Dnmt3B genes gradually increased with aging. CONCLUSIONS: Decreased autophagic activity was involved in the declines in ovarian function in aging rats. Upregulation of the DNA methyltransferases Dnmt3A and Dnmt3B may have led to methylation of the autophagy genes Atg5 and Lc3B to ultimately cause the observed decreases in autophagic activity.

Correction: Identification of Optimal Insertion Site in Recombinant Newcastle Disease Virus (rNDV) Vector Expressing Foreign Gene to Enhance Its Anti-Tumor Effect.

[This corrects the article DOI: 10.1371/journal.pone.0164723.].

Identification of Optimal Insertion Site in Recombinant Newcastle Disease Virus (rNDV) Vector Expressing Foreign Gene to Enhance Its Anti-Tumor Effect.

Recombinant Newcastle disease virus (rNDV) is tumor selective and intrinsically oncolytic, which has been developed as a vector to express exogenous genes to enhance its oncolytic efficacy. Our previous studies found that insertion sites of foreign gene in rNDV vector affected its expression and anti-tumor activities. However, the optimal insertion site for foreign genes remains unknown. In this study, we inserted the enhanced green fluorescence protein (EGFP) and IL2 genes into four different intergenic regions of the rNDV using reverse genetics technology. Recombinants rNDV-EGFPs and rNDV-IL2s were successfully rescued, which displayed the similar growth kinetics with parental virus. Both EGFP mRNA and protein levels were most abundant in HepG2 cells, when EGFP gene was inserted between the NP/P site of the rNDV. Similarly, the IL-2 expressed by HepG2 cells infected with rNDV-IL2 was highest, when IL2 was inserted into NP/P site. To test whether these rNDVs that express higher foreign genes could induce stronger anti-tumor response, we treated the H22-oxter-tumor-bearing C57BL/6J mice with rNDV-IL2s and then examined the oncolytic efficacy. The results showed that rNDV-IL2-NP/P had the strongest inhibition of murine hepatoma carcinoma tumors. The splenocytes isolated from the mice treated with rNDV-IL2-NP/P reached the highest degrees of CD4+ T and CD8+ T cells. In addition, animals' survival rate in rNDV-IL2-NP/P-treated group was higher than that of other groups. Taken together, these results demonstrate that NP and P gene junction in rNDV is the optimal insertion site for foreign genes expression to enhance rNDV's anti-tumor effects.