A Potent Combination Microbicide that Targets SHIV-RT,HSV-2 and HPV

Prevalent infection with human herpes simplex 2 (HSV-2) or human papillomavirus (HPV) is associated with increased human immunodeficiency virus (HIV) acquisition. Microbicides that target HIV as well as these sexually transmitted infections (STIs) may more effectively limit HIV incidence. Previously, we showed that a microbicide gel (MZC) containing MIV-150, zinc acetate (ZA) and carrageenan (CG) protected macaques against simian-human immunodeficiency virus (SHIV-RT) infection and that a ZC gel protected mice against HSV-2 infection. Here we evaluated a modified MZC gel (containing different buffers, co-solvents, and preservatives suitable for clinical testing) against both vaginal and rectal challenge of animals with SHIV-RT, HSV-2 or HPV. MZC was stable and safe in vitro (cell viability and monolayer integrity) and in vivo (histology). MZC protected macaques against vaginal (p<0.0001) SHIV-RT infection when applied up to 8 hours (h) prior to challenge. When used close to the time of challenge, MZC prevented rectal SHIV-RT infection of macaques similar to the CG control. MZC significantly reduced vaginal (p<0.0001) and anorectal (p = 0.0187) infection of mice when 10⁶ pfu HSV-2 were applied immediately after vaginal challenge and also when 5×10³ pfu were applied between 8 h before and 4 h after vaginal challenge (p<0.0248). Protection of mice against 8×10⁶ HPV16 pseudovirus particles (HPV16 PsV) was significant for MZC applied up to 24 h before and 2 h after vaginal challenge (p<0.0001) and also if applied 2 h before or after anorectal challenge (p<0.0006). MZC provides a durable window of protection against vaginal infection with these three viruses and, against HSV-2 and HPV making it an excellent candidate microbicide for clinical use.     

Changes in the prostaglandin levels in alcohol toxicity: effect of curcumin and N-acetylcysteine

The present study was undertaken to evaluate the potential role of curcumin, the antioxidant principal from Curcuma longa Linn., and the sulphur-containing amino acid N-acetylcysteine against ethanol-induced changes in the levels of prostanoids. Biochemical assessment of liver damage was done by measuring the activities of serum enzymes (i.e., aspartate transaminase and alkaline phosphatase), which were significantly increased in rats fed ethanol, whereas the elevated levels of these enzymes were decreased after curcumin and N-acetylcysteine treatment to rats fed ethanol. We observed a significant increase in the levels of prostaglandins E(1), E(2), F(2alpha), and D(2) in liver, kidney, and brain. Administration of curcumin and N-acetylcysteine was shown to decrease the level of these prostanoids in the tissue studied.     

Curcumin ameliorates oxidative stress during nicotine-induced lung toxicity in Wistar rats

Nicotine, a major toxic component of cigarette smoke has been identified as a major risk factor for lung related diseases. In the present study, we evaluated the protective effects of curcumin on lipid peroxidation and antioxidants status in bronchoalveolar lavage fluid (BALF) and bronchoalveolar lavage (BAL) of nicotine treated Wistar rats. Lung toxicity was induced by subcutaneous injection of nicotine at a dose of 2.5 mg/kg body weight (5 days a week, for 22 weeks) and curcumin (80 mg/kg body weight) was given simultaneously by intragastric intubation for 22 weeks. Measurement of biochemical marker enzymes: alkaline phosphatase, lactate dehydrogenase, lipid peroxidation and antioxidants were used to monitor the antiperoxidative effects of curcumin. The increased biochemical marker enzymes as well as lipid peroxides in BALF and BAL of nicotine treated rats was accompanied by a significant decrease in the levels of glutathione, glutathione peroxidase, superoxide dismutase and catalase. Administration of curcumin significantly lowered the biochemical marker enzymes, lipid peroxidation and enhanced the antioxidant status. The results of the present study suggest that curcumin exert its protective effect against nicotine-induced lung toxicity by modulating the biochemical marker enzymes, lipid peroxidation and augmenting antioxidant defense system.     

Subcellular localization and targeting of N-acetylglucosaminyl phosphatidylinositol de-N-acetylase, the second enzyme in the glycosylphosphatidylinositol biosynthetic pathway

The second step in glycosylphosphatidylinositol biosynthesis is the de-N-acetylation of N-acetylglucosaminylphosphatidylinositol (GlcNAc-PI) catalyzed by N-acetylglucosaminylphosphatidylinositol deacetylase (PIG-L). Previous studies of mouse thymoma cells showed that GlcNAc-PI de-N-acetylase activity is localized to the endoplasmic reticulum (ER) but enriched in a mitochondria-associated ER membrane (MAM) domain. Because PIG-L has no readily identifiable ER sorting determinants, we were interested in learning how PIG-L is localized to the ER and possibly enriched in MAM. We used HeLa cells transiently or stably expressing epitope-tagged PIG-L variants or chimeric constructs composed of elements of PIG-L fused to Tac antigen, a cell surface protein. We first analyzed the subcellular distribution of PIG-L and Glc-NAc-PI-de-N-acetylase activity and then studied the localization of Tac-PIG-L chimeras to identify sequence elements in PIG-L responsible for its subcellular localization. We show that human PIG-L is a type I membrane protein with a large cytoplasmic domain and that, unlike the result with mouse thymoma cells, both PIG-L and GlcNAc-PI-de-N-acetylase activity are uniformly distributed between ER and MAM in HeLa cells. Analyses of a series of Tac-PIG-L chimeras indicated that PIG-L contains two ER localization signals, an independent retention signal located between residues 60 and 88 of its cytoplasmic domain and another weak signal in the luminal and transmembrane domains that functions autonomously in the presence of membrane proximal residues of the cytoplasmic domain that themselves lack any retention information. We conclude that PIG-L, like a number of other ER membrane proteins, is retained in the ER through a multi-component localization signal rather than a discrete sorting motif.     

Characterization of the structure and the amyloidogenic properties of the Josephin domain of the polyglutamine-containing protein ataxin-3

Expansion of the polyglutamine (polyQ) region in the protein ataxin-3 is associated with spinocerebellar ataxia type 3, an inherited neurodegenerative disorder that belongs to the family of polyQ diseases. Increasing evidence indicates that protein aggregation and fibre formation play an important role in these pathologies. In a previous study, we determined the domain architecture of ataxin-3, suggesting that it comprises a globular domain, named Josephin, and a more flexible C-terminal region, that includes the polyQ tract. Here, we have characterised for the first time the biophysical properties of the isolated Josephin motif, showing that it is an autonomously folded unit and that it has no significant interactions with the C-terminal region. Study of its thermodynamic stability indicates that Josephin has an intrinsic tendency to aggregate and forms temperature-induced fibrils similar to those described for expanded ataxin-3. We show that, under destabilising conditions, the behaviours of the isolated Josephin domain and ataxin-3 are extremely similar. Our data therefore strongly suggest that the stability and aggregation properties of non-expanded ataxin-3 are determined by those of the Josephin domain, which is sufficient to reproduce the behaviour of the full-length protein. Our data support a mechanism in which the thermodynamic stability of ataxin-3 is governed by the properties of the Josephin domain, but the presence of an expanded polyQ tract increases dramatically the protein's tendency to aggregate.     

p38 MAP Kinase and MAPKAP Kinases MK2/3 Cooperatively Phosphorylate Epithelial Keratins

The MAPK-activated protein kinases (MAPKAP kinases) MK2 and MK3 are directly activated via p38 MAPK phosphorylation, stabilize p38 by complex formation, and contribute to the stress response. The list of substrates of MK2/3 is increasing steadily. We applied a phosphoproteomics approach to compare protein phosphorylation in MK2/3-deficient cells rescued or not by ectopic expression of MK2. In addition to differences in phosphorylation of the known substrates of MK2, HSPB1 and Bag-2, we identified strong differences in phosphorylation of keratin 8 (K8). The phosphorylation of K8-Ser⁷³ is catalyzed directly by p38, which in turn shows MK2-dependent expression. Notably, analysis of small molecule p38 inhibitors on K8-Ser⁷³ phosphorylation also demonstrated reduced phosphorylations of keratins K18-Ser⁵² and K20-Ser¹³ but not of K8-Ser⁴³¹ or K18-Ser³³. Interestingly, K18-Ser⁵² and K20-Ser¹³ are not directly phosphorylated by p38 in vitro, but by MK2. Furthermore, anisomycin-stimulated phosphorylations of K20-Ser¹³ and K18-Ser⁵² are inhibited by small molecule inhibitors of both p38 and MK2. MK2 knockdown in HT29 cells leads to reduced K20-Ser¹³ phosphorylation, which further supports the notion that MK2 is responsible for K20 phosphorylation in vivo. Physiologic relevance of these findings was confirmed by differences of K20-Ser¹³ phosphorylation between the ileum of wild-type and MK2/3-deficient mice and by demonstrating p38- and MK2-dependent mucin secretion of HT29 cells. Therefore, MK2 and p38 MAPK function in concert to phosphorylate K8, K18, and K20 in intestinal epithelia.     

beta-Adrenergic receptor-stimulated apoptosis in adult cardiac myocytes involves MMP-2-mediated disruption of beta1 integrin signaling and mitochondrial pathway

Stimulation of -adrenergic receptors (-AR) induces apoptosis in adult rat ventricular myocytes (ARVMs) via the JNK-dependent activation of mitochondrial death pathway. Recently, we have shown that inhibition of matrix metalloproteinase-2 (MMP-2) inhibits -AR-stimulated apoptosis and that the apoptotic effects of MMP-2 are possibly mediated via its interaction with ₁ integrins. Herein we tested the hypothesis that MMP-2 impairs ₁ integrin-mediated survival signals, such as activation of focal adhesion kinase (FAK), and activates the JNK-dependent mitochondrial death pathway. Inhibition of MMP-2 using SB3CT, a selective gelatinase inhibitor, significantly increased FAK phosphorylation (Tyr-397 and Tyr-576). TIMP-2, tissue inhibitor of MMP-2, produced a similar increase in FAK phosphorylation, whereas treatment of ARVMs with purified active MMP-2 significantly inhibited FAK phosphorylation. Inhibition of MMP-2 using SB3CT inhibited -AR-stimulated activation of JNKs and levels of cytosolic cytochrome c. Treatment of ARVMs with purified MMP-2 increased cytosolic cytochrome c release. Furthermore, inhibition of MMP-2 using SB3CT and TIMP-2 attenuated -AR-stimulated decreases in mitochondrial membrane potential. Overexpression of ₁ integrins using adenoviruses expressing the human _1A-integrin decreased -AR-stimulated cytochrome c release and apoptosis. Overexpression of ₁ integrins also inhibited apoptosis induced by purified active MMP-2. These data suggest that MMP-2 interferes with the ₁ integrin survival signals and activates JNK-dependent mitochondrial death pathway leading to apoptosis. matrix metalloproteinases; focal adhesion kinase; c-Jun NH₂-terminal kinase; cytochrome c