Regulation of human polymorphonuclear leukocytes functions by the neuropeptide pituitary adenylate cyclase-activating polypeptide after activation of MAPKs

Anti-inflammatory activities of pituitary adenylate cyclase-activating protein (PACAP) are mediated in part through specific effects on lymphocytes and macrophages. This study shows that in human polymorphonuclear neutrophils (PMNs), PACAP acts as a proinflammatory molecule. In PMNs, vaso-intestinal peptide/PACAP receptor 1 (VPAC-1) was the only receptor found to be expressed by RT-PCR. Using VPAC-1 Ab, we found that VPAC-1 mRNA was translated into proteins. In PMNs, PACAP increases cAMP, inositol triphosphate metabolites, and calcium. It activates two of the three members of the MAPK superfamily, the ERK and the stress-activated MAPK p38. U73122, an inhibitor of phospholipase C (PLC), inhibits PACAP-induced ERK activation, whereas p38 MAPK phosphorylation was unaffected. Using specific pharmalogical inhibitors of ERK (PD098059) and p38 MAPK (SB203580), we found that PACAP-mediated calcium increase was ERK and PLC dependent and p38 independent. PACAP primes fMLP-associated calcium increase; it also primes fMLP activation of the respiratory burst as well as elastase release, these last two processes being ERK and PLC dependent and p38 MAPK independent. PACAP also increases membrane expression of CD11b and release of lactoferrin and metallo proteinase-9 (MMP-9). These effects were PLC dependent (CD 11b, lactoferrin, MMP-9), ERK dependent (CD 11b, lactoferrin, MMP-9), and p38 dependent (CD11b, lactoferrin). We conclude that PACAP is a direct PMN activator as well as an effective PMN priming agent that requires PLC, ERK, and p38 MAPK activities.     

A green biocide enhancer for the treatment of sulfate-reducing bacteria (SRB) biofilms on carbon steel surfaces using glutaraldehyde

Generally speaking, a much higher concentration of biocide is needed to treat biofilms compared to the dosage used to for planktonic bacteria. With increasing restrictions of environmental regulations and safety concerns on large-scale biocide uses such as oil field applications, it is highly desirable to make more effective use of biocides. In this paper a green biocide enhancer ethylenediaminedisuccinate (EDDS) that is a biodegradable chelator, was found to enhance the efficacy of glutaraldehyde in its treatment of sulfate-reducing bacteria (SRB) biofilms. Experiments were carried out in 100 ml anaerobic vials with carbon steel coupons. The ATCC 14563 strain of Desulfovibrio desulfuricans was used. Biofilms on coupon surfaces were visualized using scanning electron microscopy (SEM). Experimental results showed that EDDS reduced the glutaraldehyde dosages considerably in the inhibition of SRB biofilm establishment and the treatment of established biofilms on carbon steel coupon surfaces.     

Automated NMR resonance assignment strategy for RNA via the phosphodiester backbone based on high-dimensional through-bond APSY experiments

A fast, robust and reliable strategy for automated sequential resonance assignment for uniformly [¹³C, ¹⁵N]-labeled RNA via its phosphodiester backbone is presented. It is based on a series of high-dimensional through-bond APSY experiments: a 5D HCP-CCH COSY, a 4D H1′C1′CH TOCSY for ribose resonances, a 5D HCNCH for ribose-to-base connection, a 4D H6C6C5H5 TOCSY for pyrimidine resonances, and a 4D H8C8(C)C2H2 TOCSY for adenine resonances. The utilized pulse sequences are partially novel, and optimized to enable long evolution times in all dimensions. The highly precise APSY peak lists derived with these experiments could be used directly for reliable automated resonance assignment with the FLYA algorithm. This approach resulted in 98 % assignment completeness for all ¹³C–¹H, ¹⁵N1/9 and ³¹P resonances of a stem-loop with 14 nucleotides.     

Changes in content and fatty acid profiles of total lipids of two halophytes: Sesuvium portulacastrum and Mesembryanthemum crystallinum under cadmium stress

Changes in lipid content and fatty acid composition were determined in leaves of two halophytes: Sesuvium portulacastrum and Mesembryanthemum crystallinum exposed to cadmium (Cd). Experiments were carried out using young small-sized plants grown hydroponically (S. portulacastrum) or aseptically germinated seeds (M. crystallinum). Cd treatment was applied at different concentrations (0, 50, 100 and 200microM) for 30 days. At high cadmium doses (200microM), contents of total lipids (TL) and lipid fractions including galactolipids (GL), phospholipids (PL) and neutral lipids (NL) decreased more in M. crystallinum leaves than in S. portulacastrum leaves. Moreover, there were no significant changes in the total fatty acid composition of S. portulacastrum leaves during metal treatment. In contrast, M. crystallinum leaves showed a decrease in the percentage of the tri-unsaturated fatty acid (C18:3), and a corresponding increase in the percentage of di-unsaturated fatty acid (C18:2). These different responses suggested that S. portulacastrum seems to be more feasible for phytoremediation.     

Circadian Rhythms of Circulating NK Cells in Healthy and Human Immunodeficiency Virus-Infected Men

Antiviral immunity involves NK cells, which circulate rhythmically every 24 hours. We have investigated circadian and 12-hour rhythms in the peripheral count of circulating NK cells in 15 men infected with human immunodeficiency virus (HIV) and 13 healthy controls. We analyzed three phenotypes using double-labeling with monoclonal antibodies and flow cytometry assessment: CD3^? CD16⁺, CD3^?CD57⁺, and CD2⁺CD3^?. A statistical validation of time-dependent differences was achieved if significance (p < 0.05) was validated both with analysis of variance and cosinor. The circadian rhythm had a similar asymmetric waveform for the three phenotypes and is homogeneous on an individual basis. The circulating NK cell count peaked in the early morning and was low at night. A circadian rhythm and a circahemidian harmonic characterized all phenotypes in healthy subjects. We considered two groups of HIV-infected men: those who were asymptomatic (eight) and those with acquired immune deficiency syndrome (AIDS) (seven). Circadian changes in NK cell count were similar in both subgroups and in healthy controls. The circadian pattern was also consistent among individual patients. Asymptomatic HIV-infected men (early-stage disease) exhibited more pronounced 12-hour rhythmicity than did patients with AIDS or controls. The circulation of NK cells does not appear to share the same synchro-nizer(s) as other circulating T- or B-lymphocyte subsets. Thus, HIV infection gradually abolished circadian rhythmicity in circulating T and B cells, whereas it did not disturb that in NK cells.     

Impaired TGF-β signaling and a defect in resolution of inflammation contribute to delayed wound healing in a female rat model of type 2 diabetes

Wound healing (WH) impairment is a well-documented phenomenon in clinical and experimental diabetes. Sex hormones, in addition to a number of signaling pathways including transforming growth factor-β1 (TGF-β1)/Smads and TNF-α/NF-κB in macrophages and fibroblasts, appear to play a cardinal role in determining the rate and nature of WH. We hypothesized that a defect in resolution of inflammation and an enhancement in TNF-α/NF-κB activity induced by estrogen deficiency contribute to the impairment of TGF-β signaling and delayed WH in diabetes models. Goto-Kakizaki (GK) rats and full thickness excisional wounds were used as models for type 2 diabetes (T2D) and WH, respectively. Parameters related to the various stages of WH were assessed using histomorphometry, western blotting, real-time PCR, immunofluorescence microscopy and ELISA-based assays. Retarded re-epithelialization, suppressed angiogenesis, delayed wound closure, reduced estrogen level and heightened states of oxidative stress were characteristic features of T2D wounds. These abnormalities were associated with a defect in resolution of inflammation, shifts in macrophage phenotypes, increased β3-integrin expression, impaired wound TGF-β1 signaling (↓p-Smad2/↑Smad7) and enhanced TNF-α/NFκB activity. Human/rat dermal fibroblasts of T2D, compared to corresponding control values, displayed resistance to TGF-β-mediated responses including cell migration, myofibroblast formation and p-Smad2 generation. A pegylated form of soluble TNF receptor-1 (PEG-sTNF-RI) or estrogen replacement therapy significantly improved re-epithelialization and wound contraction, enhanced TGFβ/Smad signaling, and polarized the differentiation of macrophages toward an M2 or "alternatively" activated phenotype, while limiting secondary inflammatory-mediated injury. Our data suggest that reduced estrogen levels and enhanced TNF-α/NF-κB activity delayed WH in T2D by attenuating TGFβ/Smad signaling and impairing the resolution of inflammation; most of these defects were ameliorated with estrogen and/or PEG-sTNF-RI therapy.     

Effects of CaCl2 pretreatment on antioxidant enzyme and leaf lipid content of faba bean (Vicia faba L.) seedlings under cadmium stress

Most polyploids can survive better under multiple stress conditions than their corresponding diploid; however, there is no established theory that can adequately explain this phenomenon at the molecular or physiological level. Here, we attempt to explain this interesting but puzzling problem from the perspectives of resource requirement and antioxidant response. In this experiment, we compared the antioxidative response and stomatal behavior of two ploidy levels of tobacco plants (tetraploid and its colchicine-induced octaploid) under drought, cold and nutrient deficit stress conditions. In comparison to tetraploid, less H₂O₂ accumulation and stronger reactive oxygen scavenging capacity (antioxidant enzyme activities and DPPH radical scavenging capacity) were observed in octaploid under stress free or stressful conditions. In accordant with these, less oxidative damage and higher redox values (ASC/DHA and GSH/GSSG) were also monitored in the octaploid than in the tetraploid under same conditions. In addition, a higher net rate of photosynthesis (Pn) and slower decline in the concentration of intercellular CO₂(Ci) were measured in the octaploid compared to the tetraploid following high concentration ABA treatment (20 mg L⁻¹), with more severe oxidative damage observed in the tetraploid than in the octaploid. On the basis of the resource acquisition theory, we consider that any environmental stress that can lower plant resource availability would favor survival in a slow-growing polyploid compared with that in a fast-growing diploid.     

Acadesine Kills Chronic Myelogenous Leukemia (CML) Cells through PKC-Dependent Induction of Autophagic Cell Death

CML is an hematopoietic stem cell disease characterized by the t(9;22) (q34;q11) translocation encoding the oncoprotein p210BCR-ABL. The effect of acadesine (AICAR, 5-Aminoimidazole-4-carboxamide-1-β-D-ribofuranoside) a compound with known antileukemic effect on B cell chronic lymphoblastic leukemia (B-CLL) was investigated in different CML cell lines. Acadesine triggered loss of cell metabolism in K562, LAMA-84 and JURL-MK1 and was also effective in killing imatinib-resistant K562 cells and Ba/F3 cells carrying the T315I-BCR-ABL mutation. The anti-leukemic effect of acadesine did not involve apoptosis but required rather induction of autophagic cell death. AMPK knock-down by Sh-RNA failed to prevent the effect of acadesine, indicating an AMPK-independent mechanism. The effect of acadesine was abrogated by GF109203X and Ro-32-0432, both inhibitor of classical and new PKCs and accordingly, acadesine triggered relocation and activation of several PKC isoforms in K562 cells. In addition, this compound exhibited a potent anti-leukemic effect in clonogenic assays of CML cells in methyl cellulose and in a xenograft model of K562 cells in nude mice. In conclusion, our work identifies an original and unexpected mechanism by which acadesine triggers autophagic cell death through PKC activation. Therefore, in addition to its promising effects in B-CLL, acadesine might also be beneficial for Imatinib-resistant CML patients.     

Exogenous nitric oxide alleviates manganese toxicity in bean plants by modulating photosynthesis in relation to leaf lipid composition

Nitric oxide (NO) is a signaling molecule controlling several steps of plant development and defense process under stress conditions. NO-induced alleviation of manganese (Mn) toxicity was investigated on bean plants submitted for 28 days to 500 µM MnCl₂. Manganese excess decreased plant dry weight and elongation and increased levels of reactive oxygen species and lipid peroxidation leading to up-regulation of superoxide dismutase, catalase, and ascorbate peroxidase activities. The inhibitory effects of Mn on plant growth were associated to reduction of light-saturated carbon assimilation (A_max), stomatal conductance (g_s), and transpiration (E). By contrast, Mn induced significant increase in the apparent quantum yield (ɸ) and light compensation point (LCP). Interestingly, intracellular CO₂ (Ci) remains stable under Mn stress. Concomitantly, leaf membrane lipids have drastically reduced under high Mn concentration. After Mn exposition, leaf fatty acids exhibited a significant loss of linolenic acid, accompanied by an accumulation of palmitoleic, stearic, and linoleic acids leading to alteration of lipid desaturation. NO supply reversed Mn toxicity as evidenced by enhancement of growth biomass and recovery of A_max, E, ɸ, and LCP. Similarly, NO addition has positive effects on leaf lipid content and composition leading to restoration of lipid unsaturation. The modulation of fatty acid composition can be a way to reduce leaf membrane damages and maintain optimal photosynthesis and plant growth. Despite the absence of enough evidences in how NO is involved in lipid and photosynthesis recovery under Mn stress conditions, it is assumed that NO beneficial effects are attributable to NO/Mn cross-talk.