Month: March 2018

Mitochondria are multifunctional organelles and mitochondrial activity is important for cellular proliferation and physiology. For example, the mitochondria play essential roles in cellular energy production via the tricarboxylic acid cycle coupled to oxidative phosphorylation, as well as Axitinib during apoptosis via reactive oxygen species generation and cytochrome c release. Several studies have indicated that mitochondrial dysfunction contributes to the development and progression of various human diseases, including cancer. A hallmark of tumor cells is altered metabolism supporting rapid cellular proliferation. Many metabolic intermediates that support cell growth are provided by the mitochondria ; consequently, the identification of proteins that regulate mitochondrial metabolic pathways is of great interest, and we sought to understand whether the VDR may modulate these pathways. In the present study, using our previously described model, we genetically silenced the receptor and examined the effects on cell growth, mitochondrial metabolism and biosynthetic pathways. The collected data provide evidence of a novel role of the VDR as a negative regulator of respiratory chain activity, and we highlight the repercussions for cellular anabolism and growth produced by the VDR on mitochondrial respiration. Based on our observations, we conclude that the VDR, by restraining mitochondrial respiratory activity, allows the cell to spare metabolic intermediates, which may be diverted from oxidative metabolism toward a biosynthetic fate, supporting cell growth. We validated the general role of the VDR as an enhancer of cellular proliferation extending our observations to several human cancer cell lines. The differentiating and antiproliferative action of vitamin D in vitro has been previously described in literature. Such effects are mediated by transcriptional control, which is preceded by BIBW2992 nuclear translocation and does not occur in vitamin D-stimulated HaCaT cells. HaCaT cells appear to be resistant to the nuclear antiproliferative effects of vitamin D, and accordingly, we found that vitamin D treatment did not alter the growth rate of HaCaT cells. Thus, HaCaT cells represent a model of resistance to the differentiating properties of vitamin D, and there is not any incongruity between the nuclear antiproliferative role of vitamin D described in literature and the proliferative effects exerted by VDR in our cell model. The results of our silencing experiments show that VDR in HaCaT cells enhances cell growth.

While numerous studies have evaluated the cell death inducing effect of several flavonoids in cancer cells, the effects of flavonoids on autophagy are poorly documented. However, massive acidic vacuolization was observed upon in vitro treatment of cells with prenylflavonoids, Quercetin and Curcimin. Induction of autophagy by flavonoids or flavonoid-containing multiherbal preparation was seen to induce apoptotic and non-apoptotic, caspase independent celldeath. Moreover, blocking of autophagosome maturation by flavonoids was seen to result in apoptosis recently. Considering these opposite effects, specified research is necessary to unravel the diverse effects of flavonoids on autophagy and apoptosis. We report for the first time the induction of autophagy in a metastatic SCC cell line following treatment with the flavonoid LUT. Furthermore, we assessed the contribution of LUT-dependent autophagy induction to the increased survival of MET4 cells using the lysosomotropic agent chloroquine, which prevents lysosomal degradation. The marked increase of cell death detected upon CQ co-treatment, suggested that addition of a late phase autophagy inhibitor to LUT reduced chemoresistance of metastatic SCC. Notably, addition of 3-MA, an early stage autophagy inhibitor, diminished the improved apoptosis induction by CQ in LUT treated cells, suggesting that accumulation of lysosomes is necessary for the cell death inducing effect of LUT. A different outcome of autophagy inhibition depending on the stage of autophagy inhibition, has been reported earlier in an Imatinib study. The combination of an autophagy inhibitor with agents that induce autophagy in cancer cells as a survival response has been proposed recently as a novel cancer therapeutic strategy. For instance, combination of CQ or hydroxychloroquine with chemotherapy, targeted therapy or radiotherapy is currently under intensive investigation in preclinical as well as clinical trials. Thus, cancer appears to be a promising indication for this old drug CQ, which is widely used as an anti-malarial and anti-rheumatic drug. In summary, different human malignant keratinocyte cell lines treated with LUT showed increased apoptotic cell death, while normal human keratinocytes remained unaffected. In addition, the efficacy of LUT to induce apoptosis appeared to be tumor progression dependent. Whereas primary MET1 tumor cells were very sensitive to AKT-inhibition by LUT, complete inhibition of AKT signaling in metastatic MET4 cells was not sufficient for notable cell death induction. However, LUT induced massive autophagy in MET4 cells, which was paralleled by a vast increase in acidic vacuoles. We showed that simultaneous inhibition of late phase autophagy SB431542 resulted in a sensitization of the resistant MET4-cells to LUT-induced cell death. Altogether, our in vitro data suggest that LUT may provide a therapeutic tool for the treatment of patients with advanced SCC and that resistance may be circumvented by supplementation of autophagy inhibitors, like CQ. Additional studies are MK-0683 warranted to further investigate the therapeutic value and clinical usefulness of LUT.

With respect to the role of the Msr proteins, it is well documented that these enzymes contribute to the ability of a pathogen to adhere to host tissue, evade immune system, form biofilms, survive inside macrophages, and resist oxidative killing.MsrA protein contributes to cell wall integrity and maintenance of adhesion properties in Streptococcus gordonii. Msr proteins have also been shown to affect adherence properties of pathogenic Neisseria. In S. gordonii, the MsrA enzyme was shown to maintain the integrity of bacterial adhesins during oxidative stress. The current study confirms the role of Msr proteins, particularly the MsrAs in the adherence of S. aureus to human cells. The MsrA1-deficient S. aureus, the triple msrA and the quadruple msrAB null-mutants, all showed reduced adherence to lung MK-4827 PARP inhibitor epithelial cells. The role of Msr proteins in virulence of the bacterial pathogens is also well documented. Both MsrA and MsrB contributed to the enzymatic defenses of Mycobacterium tuberculosis from reactive oxygen species. In Pseudomonas aeruginosa, inactivation of either msrA or msrB or both reduced virulence and increased its killing by oxidants. In Campylobacter jejuni, the single msrA or msrB mutants showed no growth defect, but the msrA-msrB double mutant showed increased sensitivity to oxidative stress conditions. Mutation in the msrA or msrB gene in Enterococcus faecalis resulted in increased sensitivity to H2O2. In addition, an msrA msrB double mutant showed further increase in sensitivity suggesting that the effect of mutations were additive. In a later study, however, the msrA and msrB mutants were shown to behave differently; the msrA mutant was more sensitive to oxidative stress LEE011 conditions whereas the msrB mutant showed stimulated growth under similar conditions. In Salmonella Typhimurium, deletion of msrA increased bacterial susceptibility to H2O2 and reduced its virulence, but a mutation in msrB had no apparent phenotype. In Mycobacterium smegmatis also, MsrB was shown to have a limited role in protection from oxidative stress conditions. Thus, the role of MsrB protein in defense from oxidative stress is questionable in many bacterial species. It is possible that under oxidative stress the majority of the oxidized methionine is S-MetO and the MsrB protein has no activity against this epimer. This may be the reason why the MsrA-deficient bacteria showed a high sensitivity to conditions that impose oxidative stress. MsrB of S. aureus, seems to some extent, counterbalance the effect of MsrA1. For example, lack of MsrA1 reduces pigmentation and this may be due to previously shown higher level of MsrB in MsrA1-deficient S. aureus.

Potassium bromate is a food additive that is extensively used as a maturing agent for flour and as a dough conditioner. It is also used in cosmetics and is a component of permanent hair weaving solutions. Disinfection of drinking water by ozonation, which has emerged as a promising alternative to chlorination since it does not result in the production of hazardous agents like trihalomethanes, also generates bromate as a by-product. During ozonation, the bromide contained in water naturally is oxidized to bromate which is thus frequently detected in tap and even bottled water. Exposure to KBrO3 results in multiple organ toxicity with kidney being the primary target organ of this compound. KBrO3 has been shown to alter gene expression in renal tissues and chronic administration of KBrO3 induces carcinomas in rats, hamsters and mice. Bromate is now considered as a probable human carcinogen and a complete carcinogen in animals. Increased production of reactive oxygen species and free SAR131675 radicals has been implicated in mediating KBrO3-induced toxicity. These radicals can cause extensive tissue damage by reacting with macromolecules like proteins, nucleic acids and membrane lipids which causes an imbalance in homeostasis and leads to tissue injury. Supporting the Crizotinib involvement of ROS in its action, several antioxidants have been shown to ameliorate the bromate-induced multiple organ toxicity. Taurine is a conditionally essential amino acid found in large concentrations in all mammalian tissues and accounts for approximately 0.1% of total human body weight. It is present in various foods like eggs, milk and is especially abundant in seafood and meat. Taurine is involved in a number of crucial physiological processes including modulation of calcium flux and neuronal excitability, osmoregulation, detoxification, membrane stabilization, reproduction and immunity. It is essential for the development and survival of mammalian cells, particularly those of the cerebellum, retina and kidney. Taurine is also an AO and a potent scavenger of the hydroxyl radical suggesting that it may be useful in treating oxygen radical mediated toxicity. Taurine protects tissues from various pathological conditions resulting from free radicals generated upon exposure to various xenobiotics. We have recently shown that administration of KBrO3 to rats induces oxidative stress and lowers the activities of several enzymes in the intestinal brush border membrane. It causes alterations in the activities of various antioxidant and metabolic enzymes and damages the intestinal DNA. In the present work, we have used taurine to attenuate the KBrO3-induced intestinal damage using rats as the animal model. This was done in view of the effectiveness of taurine in mitigating toxicities involving ROS and OS.

In the present study, we show that i.v. infusion of young monocytes does not have a significant effect on overall plaque load, however, does result in significant reductions of specific plaque sizes. These data suggest that young monocytes are able to gain entry into the brain or activate other pathways that result in plaque remodeling and possible clearance in the brain. However, it could be possible that monocyte entry into the brain is somewhat diminished due to the loss of certain surface markers immediately following bead isolation. However, we have shown that this expression reappears after 24 h, however, such findings could explain why we observe less positive effects on plaque deposition and cognition. In addition, it could be possible that monthly infusions of 5 x 106 monocytes might not be frequent enough to induce a significant reduction in amyloid plaque load. A previous study demonstrated that twice weekly infusions of CD11b+ bone marrow cells could arrest amyloid deposition in an AD transgenic mouse model. Thus, more frequent infusions may be required to attenuate amyloid deposition or a longer ICG-001 experimental set-up that provides more time for cells to rid the brain of amyloid. Others have shown that bone marrowderived cells are detected in mice as soon as 24 h and up to four weeks following hypoxic-ischemic brain injury despite injection 6 months prior. Further, we were interested in determining whether these alterations also translated into changes in cortical APP protein levels. Here, we report that no significant differences in APP expression were found in the cortex between APPSwDI mice given monocyte or saline infusions. This data suggests that monocyte infusions do not alter APP processing or expression in the cortex, however, it could also be possible that changes in APP protein levels are present at earlier stages of the disease. Microglia are considered the resident immune cells of the CNS, responsible for surveying the brain and responding to first signs of insult or injury. In both human AD and mouse transgenic AD models, activated microglia are found closely associated to amyloid plaques, indicating their potentially important role in A�� and plaque pathology. However, delineating the role of these cells in AD has proven difficult. In vitro and in vivo studies have shown that microglia can phagocytose A��, whereas, others have demonstrated that complete ablation of these cells has little to no effect on plaque deposition. Moreover, studies indicate that microglia might develop a proinflammatory or neurotoxic phenotype in response to A�� exposure, contributing to further disease aggravation and progression. Here, we show that Iba1 staining, a marker for microglial/SCH772984 abmole macrophage activation, is significantly reduced in animals receiving monocyte infusions. The observable morphological changes of these cells also points to diminished cell activation. These findings indicate that monocyte infusions could play a role in suppressing microglial activation. However, further investigations are needed to understand whether this also includes altering properties involved in phagocytosis, the release of neurotoxic species, and the release of proinflammatory cytokines. In addition to microglial activation, we were also interested in determining whether monocyte infusions could have a detrimental effect on cytotoxicity and neuroinflammation in the APPSwDI mouse brain. In this study, we demonstrated that monthly i.v. monocyte infusions do not significantly alter catalase, MMP-2 or proinflammatory cytokines in the cortices or plasma of APPSwDI mice.