Formation of self-organized Zircaloy-4 oxide nanotubes in organic viscous electrolyte via anodization

This work reports the formation of self-organized Zircaloy-4 (Zr-4) oxide nanotubes in viscous organic ethylene glycol (EG) electrolyte containing a small amount of fluoride salt and deionized (DI) water via an electrochemical anodization. The structure, morphology, and composition of the Zr-4 oxide nanotubes were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), EDX, and XPS. SEM results showed that the length of the nanotubes is approximately 13 μm, and TEM results showed that the inner diameter of the Zr-4 oxide nanotubes is approximately 20 nm with average wall thickness of approximately 7 nm. XRD and selected area electron diffraction pattern (SAED) results confirmed that the as-anodized Zr-4 oxide nanotubes have cubic crystalline structure. Both cubic and monoclinic phases were found after annealing of Zr-4 oxide nanotubes. The tubular structure morphology of Zr-4 oxide nanotubes did not remain intact after annealing which is attributed to the elimination of F species from the annealed nanotubes.     

The Protective Effect of Zebularine,an Inhibitor of DNA Methyltransferase,on Renal Tubulointerstitial Inflammation and Fibrosis

Renal fibrosis, the final pathway of chronic kidney disease, is caused by genetic and epigenetic mechanisms. Although DNA methylation has drawn attention as a developing mechanism of renal fibrosis, its contribution to renal fibrosis has not been clarified. To address this issue, the effect of zebularine, a DNA methyltransferase inhibitor, on renal inflammation and fibrosis in the murine unilateral ureteral obstruction (UUO) model was analyzed. Zebularine significantly attenuated renal tubulointerstitial fibrosis and inflammation. Zebularine decreased trichrome, α-smooth muscle actin, collagen IV, and transforming growth factor-β1 staining by 56.2%. 21.3%, 30.3%, and 29.9%, respectively, at 3 days, and by 54.6%, 41.9%, 45.9%, and 61.7%, respectively, at 7 days after UUO. Zebularine downregulated mRNA expression levels of matrix metalloproteinase (MMP)-2, MMP-9, fibronectin, and Snail1 by 48.6%. 71.4%, 31.8%, and 42.4%, respectively, at 7 days after UUO. Zebularine also suppressed the activation of nuclear factor-κB (NF-κB) and the expression of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-1β, and IL-6, by 69.8%, 74.9%, and 69.6%, respectively, in obstructed kidneys. Furthermore, inhibiting DNA methyltransferase buttressed the nuclear expression of nuclear factor (erythroid-derived 2)-like factor 2, which upregulated downstream effectors such as catalase (1.838-fold increase at 7 days, p < 0.01), superoxide dismutase 1 (1.494-fold increase at 7 days, p < 0.05), and NAD(P)H: quinone oxidoreduate-1 (1.376-fold increase at 7 days, p < 0.05) in obstructed kidneys. Collectively, these findings suggest that inhibiting DNA methylation restores the disrupted balance between pro-inflammatory and anti-inflammatory pathways to alleviate renal inflammation and fibrosis. Therefore, these results highlight the possibility of DNA methyltransferases as therapeutic targets for treating renal inflammation and fibrosis.     

Expression and Characterization of Monomeric Recombinant Isocitrate Dehydrogenases from Corynebacterium glutamicum and Azotobacter vinelandii for NADPH Regeneration

The enzymatic transformation of various chemicals, especially using NADPH-dependent hydroxylase, into more soluble and/or high value-added products has steadily garnered increasing attention. However, the industrial application of these NADPH-dependent hydroxylases has been limited due to the high cost of the cofactor NADPH. As an alternative, enzymatic NADPH-regeneration systems have been developed and are frequently used in various fields. Here, we expressed and compared two recombinant isocitrate dehydrogenases (IDHs) from Corynebacterium glutamicum and Azotobacter vinelandii in Escherichia coli. Both enzymes were hyper-expressed in the soluble fraction of E. coli and were single-step purified to apparent homogeneity with yields of more than 850 mg/L. These enzymes also functioned well when paired with NADPH consumption systems. Specifically, NADPH was regenerated from NADP⁺ when an NADPH-consuming cytochrome P450 BM3 from Bacillus megaterium was incorporated. Therefore, both enzymes could be used as alternatives to the commonly used regeneration system for NADPH. These enzymes also have promising potential as genetic fusion partners with NADPH-dependent enzymes due to the monomeric nature of their quaternary structure, thereby resulting in self-sufficient biocatalysts via NADPH regeneration in a single polypeptide with NADPH-dependent activity.     

Therapeutic Effects of Saponins for the Prevention and Treatment of Cancer by Ameliorating Inflammation and Angiogenesis and Inducing Antioxidant and Apoptotic Effects in Human Cells

Saponins are natural compounds found in plants and have a diverse range of applications. However, the therapeutic potential of saponins in regulating cytotoxicity, angiogenesis, and inflammation in mammalian cells is yet to be explored. Here, we investigated the therapeutic effects of saponins from green tea by exploring the cytotoxic effects of saponins by inducing apoptosis in the human cancer cell lines hepatocellular carcinoma (HEPG2) and colorectal adenocarcinoma (HT29). The anti-angiogenesis effect of saponins was also investigated in human umbilical vein endothelial cells (HUVEC). We explored the ability of saponins to attenuate inflammation in a dose-dependent manner in normal human cells. It was found that saponins exhibit cytotoxic effects in cancer cells and not in normal cells at the same concentration. Cytotoxicity was measured by inducing apoptosis by enhancing caspase-3 (cas-3) activation and B-cell lymphoma-2 (Bcl-2)-associated X protein (BAX) gene expression and suppressing the antiapoptotic protein, Bcl-2. The inhibition of HUVEC proliferation was due to the suppression of the phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), vascular endothelial growth factor receptor-2 (VEGFR-2), and nuclear factor kappa B (NF-κB). We also observed the antioxidant potential of green tea-derived saponins against free radicals in reactive oxygen species (ROS)-induced cells. Here we observed that the saponins exhibited free radical scavenging activities and activated nuclear factorerythroid 2-related factor 2 (NRF-2) leading to the upregulation of antioxidant-related genes in human embryonic kidney 293 (HEK293) cells. Furthermore, we demonstrated that the anti-inflammatory effects were due to the suppression of pro-inflammatory cytokines interleukin (IL)-1β, IL-6, tumor necrosis factor-alpha (TNF-α), and inducible nitric oxide synthase (iNOS) in HEK293 cells. The significance of the work is we are the first to report on the anti-cancer effects of saponins based on the anti-inflammatory, antioxidant, anti-angiogenesis, and apoptosis induction properties. In conclusion, green tea-derived saponins could be effective therapeutics for the treatment of cancer.     

Inhibitory Activities of Rare Ginsenoside Rg4 on Cecal Ligation and Puncture-Induced Sepsis

Sepsis is an uncontrolled response to inflammatory infection and is associated with high levels of mortality and morbidity. Rg4 is a rare ginsenoside mainly found in the leaves of Panax ginseng C. A. Meyer and the major protopanaxatriol-type ginsenoside of black ginseng. In this study, we determined whether Rg4 affects cecal ligation and puncture (CLP)-induced sepsis. Animals were separated into the following six groups: control group, CLP-operated group, CLP plus maslinic acid (MA), and CLP plus Rg4 (5, 10, or 15 mg/kg). Survival rate, body weight changes, inflammatory cytokines, and histological analyses were assessed. Human endothelial cells were activated with the high-mobility group box 1 (HMGB1) protein and Rg4. Cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Enzyme-linked immunosorbent assay (ELISA) and Western blot analysis were used to assess inflammation and gene expression, respectively. After CLP surgery, the Rg4-administered group exhibited a higher survival rate and body weight compared with the untreated control group. Rg4 treatment reduced cytokine levels, including tumor necrosis factor (TNF)-α and interleukin (IL)-1β, as well as nitric oxide (NO) levels and renal inflammation. After Rg4 treatment of HMGB1-activated cells, the expressions of toll-like receptor (TLR) 4 and TNF-α were decreased, and the activation of phosphoinositide 3-kinase (PI3K)/AKT signaling increased cell viability. In summary, Rg4 inhibited inflammation and exhibited a protective effect against CLP-induced sepsis, thereby reinforcing cell survival against septic responses.     

Vitamin C Suppresses Pancreatic Carcinogenesis through the Inhibition of Both Glucose Metabolism and Wnt Signaling

Cumulative studies have indicated that high-dose vitamin C has antitumor effects against a variety of cancers. However, the molecular mechanisms underlying these inhibitory effects against tumorigenesis and metastasis, particularly in relation to pancreatic cancer, are unclear. Here, we report that vitamin C at high concentrations impairs the growth and survival of pancreatic ductal adenocarcinoma (PDAC) cells by inhibiting glucose metabolism. Vitamin C was also found to trigger apoptosis in a caspase-independent manner. We further demonstrate that it suppresses the invasion and metastasis of PDAC cells by inhibiting the Wnt/β-catenin-mediated epithelial-mesenchymal transition (EMT). Taken together, our results suggest that vitamin C has therapeutic effects against pancreatic cancer.     

Characteristics of Exosomes and the Vascular Landscape Regulate Exosome Sequestration by Peripheral Tissues and Brain

Exosomes mediate intercellular communication, shuttling messages between cells and tissues. We explored whether exosome tissue sequestration is determined by the exosomes or the tissues using ten radiolabeled exosomes from human or murine, cancerous or noncancerous cell lines. We measured sequestration of these exosomes by the liver, kidney, spleen, and lung after intravenous injection into male CD-1 mice. Except for kidney sequestration of three exosomes, all exosomes were incorporated by all tissues, but sequestration levels varied greatly among exosomes and tissues. Species of origin (mouse vs. human) or source (cancerous vs. noncancerous cells) did not influence tissue sequestration. Sequestration of J774A.1 exosomes by liver involved the mannose-6 phosphate (M6P) receptor. Wheatgerm agglutinin (WGA) or lipopolysaccharide (LPS) treatments enhanced sequestration of exosomes by brain and lung but inhibited sequestration by liver and spleen. Response to LPS was not predictive of response to WGA. Path and heat map analyses included our published results for brain and found distinct clusters among the exosomes and the tissues. In conclusion, we found no evidence for a universal binding site controlling exosome-tissue interactions. Instead, sequestration of exosomes by tissues is differentially regulated by both exosomes and tissues and may be stimulated or inhibited by WGA and inflammation.     

PRMT7 Inhibitor SGC8158 Enhances Doxorubicin-Induced DNA Damage and Its Cytotoxicity

Protein arginine methyltransferase 7 (PRMT7) regulates various cellular responses, including gene expression, cell migration, stress responses, and stemness. In this study, we investigated the biological role of PRMT7 in cell cycle progression and DNA damage response (DDR) by inhibiting PRMT7 activity with either SGC8158 treatment or its specific siRNA transfection. Suppression of PRMT7 caused cell cycle arrest at the G₁ phase, resulting from the stabilization and subsequent accumulation of p21 protein. In addition, PRMT7 activity is closely associated with DNA repair pathways, including both homologous recombination and non-homologous end-joining. Interestingly, SGC8158, in combination with doxorubicin, led to a synergistic increase in both DNA damage and cytotoxicity in MCF7 cells. Taken together, our data demonstrate that PRMT7 is a critical modulator of cell growth and DDR, indicating that it is a promising target for cancer treatment.