Different Plasma Markers of Inflammation Are Influenced by Immune Recovery and cART Composition or Intensification in Treated HIV Infected Individuals

Background

HIV-1 infection increases plasma levels of inflammatory markers. Combination antiretroviral therapy (cART) does not restore inflammatory markers to normal levels. Since intensification of cART with raltegravir reduced CD8 T-cell activation in the Discor-Ral and IntegRal studies, we have evaluated the effect of raltegravir intensification on several soluble inflammation markers in these studies.

Methods

Longitudinal plasma samples (0–48 weeks) from the IntegRal (n = 67, 22 control and 45 intensified individuals) and the Discor-Ral studies (44 individuals with CD4 T-cell counts<350 cells/µl, 14 control and 30 intensified) were assayed for 25 markers. Mann-Whitney, Wilcoxon, Spearman test and linear mixed models were used for analysis.

Results

At baseline, different inflammatory markers were strongly associated with HCV co-infection, lower CD4 counts and with cART regimens (being higher in PI-treated individuals), but poorly correlated with detection of markers of residual viral replication. Although raltegravir intensification reduced inflammation in individuals with lower CD4 T-cell counts, no effect of intensification was observed on plasma markers of inflammation in a global analysis. An association was found, however, between reductions in immune activation and plasma levels of the coagulation marker D-dimer, which exclusively decreased in intensified patients on protease inhibitor (PI)-based cART regimens (P = 0.040).

Conclusions

The inflammatory profile in treated HIV-infected individuals showed a complex association with HCV co-infection, the levels of CD4 T cells and the cART regimen. Raltegravir intensification specifically reduced D-dimer levels in PI-treated patients, highlighting the link between cART composition and residual viral replication; however, raltegravir had little effect on other inflammatory markers.     

An amphiphilic, PK/PBAN analog is a selective pheromonotropic antagonist that penetrates the cuticle of a heliothine insect

A linear pyrokinin (PK)/pheromone biosynthesis activating neuropeptide (PBAN) antagonist lead (RYF[dF]PRLa) was structurally modified to impart amphiphilic properties to enhance its ability to transmigrate the hydrophobic cuticle of noctuid moth species and yet retain aqueous solubility in the hemolymph to reach target PK/PBAN receptors within the internal insect environment. The resulting novel PK/PBAN analog, Hex-Suc-A[dF]PRLa (PPK-AA), was synthesized and evaluated as an antagonist in a pheromonotropic assay in Heliothis peltigera against 4 natural PK/PBAN peptide elicitors (PBAN; pheromonotropin, PT; myotropin, MT; leucopyrokinin, LPK) and in a melanotropic assay in Spodoptera littoralis against 3 natural PK/PBAN peptide elicitors (PBAN, PT, LPK). The analog proved to be a potent and efficacious inhibitor of sex pheromone biosynthesis elicited by PBAN (84% at 100 pmol) and PT (54% at 100 pmol), but not by MT and LPK. PPK-AA is a selective pure antagonist (i.e., does not exhibit any agonistic activity) as it failed to inhibit melanization elicited by any of the natural PK/PBAN peptides. The analog was shown to transmigrate isolated cuticle dissected from adult female Heliothis virescens moths to a high extent of 25-30% (130-150 pmol), representing physiologically significant quantities. PPK-AA represents a significant addition to the arsenal of tools available to arthropod endocrinologists studying the endogenous mechanisms of PK/PBAN regulated processes, and a prototype for the development of environmentally friendly pest management agents capable of disrupting the critical process of reproduction.     

Oligodendrocytes depend on MCL-1 to prevent spontaneous apoptosis and white matter degeneration

Neurologic disorders often disproportionately affect specific brain regions, and different apoptotic mechanisms may contribute to white matter pathology in leukodystrophies or gray matter pathology in poliodystrophies. We previously showed that neural progenitors that generate cerebellar gray matter depend on the anti-apoptotic protein BCL-xL. Conditional deletion of Bcl-xL in these progenitors produces spontaneous apoptosis and cerebellar hypoplasia, while similar conditional deletion of Mcl-1 produces no phenotype. Here we show that, in contrast, postnatal oligodendrocytes depend on MCL-1. We found that brain-wide Mcl-1 deletion caused apoptosis specifically in mature oligodendrocytes while sparing astrocytes and oligodendrocyte precursors, resulting in impaired myelination and progressive white matter degeneration. Disabling apoptosis through co-deletion of Bax or Bak rescued white matter degeneration, implicating the intrinsic apoptotic pathway in Mcl-1-dependence. Bax and Bak co-deletions rescued different aspects of the Mcl-1-deleted phenotype, demonstrating their discrete roles in white matter stability. MCL-1 protein abundance was reduced in eif2b5-mutant mouse model of the leukodystrophy vanishing white matter disease (VWMD), suggesting the potential for MCL-1 deficiency to contribute to clinical neurologic disease. Our data show that oligodendrocytes require MCL-1 to suppress apoptosis, implicate MCL-1 deficiency in white matter pathology, and suggest apoptosis inhibition as a leukodystrophy therapy.Subject terms: Cell death in the nervous system, Neurodegeneration, Oligodendrocyte     

Spatio-temporal scales of dispersal limitation in the recolonization of a semi-arid mediterranean old-field

Dispersal and establishment limitations have been proposed as important mechanisms that control vegetation colonization processes. While many studies have emphasized the role of dispersal limitation in the dynamics of plant communities, little is known about the spatial and temporal scales at which dispersal limitation affects plant population dynamics. In this study we investigate spatial and temporal scales of dispersal limitation in a system of semi-arid Mediterranean old-fields recolonized by the dominating dwarf shrub Sarcopoterium spinosum (Rosaceae). Our analysis was based on a combination of two complementary approaches: 1) age analysis of S. spinosum shrubs growing at different distances from source populations, and 2) a corresponding analysis of changes in vegetation cover since recolonization onset (ca 55 yr ago), based on information obtained from historical aerial-photographs. Shrubs sampled in plots near the source populations were similar in their age distribution to the source populations, but significantly different from shrubs sampled far from the source populations. Increasing distance from source populations was associated with a decrease in median age of the shrubs, and in the density and relative frequency of adult shrubs (>15 yr). These patterns of changes in age structure occurred over distances of several tenths of meters. Young age groups (<5 yr) were scarcely represented in all plots, suggesting that establishment limitation was also important in determining recolonization rates. Analysis of the aerial photographs supported the results of the age analysis, showing evidence for both distance effect and establishment limitation. We conclude that dispersal limitation may have a long-term impact on vegetation patterns, even at small spatial scales, and that dispersal limitation interacts with establishment limitation in determining recolonization processes.     

High level expression in Escherichia coli of isopenicillin N synthase genes from Flavobacterium and Streptomyces, and recovery of active enzyme from inclusion bodies

A T7 promoter-based vector was used to express the isopenicillin N synthase (IPNS) genes of Flavobacterium sp. 12,154 and Streptomyces jumonjinensis in Escherichia coli. Most of the IPNS synthesized at 37 degrees C, and representing some 22% and 51% of the total cell protein respectively, occurred in an insoluble, enzymatically inactive form. Active IPNS was recovered in a rapid and simple two-step procedure in which the insoluble material was first denatured in 5 M urea and then refolded by passing the solubilized IPNS through a G-25 Sephadex sizing column. Further chromatography on DEAE-Sepharose resulted in highly active IPNS preparations. This procedure was found to be well suited for scaling up to produce large amounts of IPNS.     

Halofuginone improves muscle-cell survival in muscular dystrophies

Halofuginone has been shown to prevent fibrosis via the transforming growth factor-β/Smad3 pathway in muscular dystrophies. We hypothesized that halofuginone would reduce apoptosis—the presumed cause of satellite-cell depletion during muscle degradation—in the mdx mouse model of Duchenne muscular dystrophy. Six-week-old mdx mouse diaphragm exhibited fourfold higher numbers of apoptotic nuclei compared with wild-type mice as determined by a TUNEL assay. Apoptotic nuclei were found in macrophages and in Pax7-expressing cells; some were located in centrally-nucleated regenerating myofibers. Halofuginone treatment of mdx mice reduced the apoptotic nuclei number in the diaphragm, together with reduction in Bax and induction in Bcl2 levels in myofibers isolated from these mice. A similar effect was observed when halofuginone was added to cultured myofibers. No apparent effect of halofuginone was observed in wild-type mice. Inhibition of apoptosis or staurosporine-induced apoptosis by halofuginone in mdx primary myoblasts and C2 myogenic cell line, respectively, was reflected by less pyknotic/apoptotic cells and reduced Bax expression. This reduction was reversed by a phosphinositide-3-kinase and mitogen-activated protein kinase/extracellular signal-regulated protein kinase inhibitors, suggesting involvement of these pathways in mediating halofuginone's effects on apoptosis. Halofuginone increased apoptosis in α smooth muscle actin- and prolyl 4-hydroxylase β-expressing cells in mdx diaphragm and in myofibroblasts, the major source of extracellular matrix. The data suggest an additional mechanism by which halofuginone improves muscle pathology and function in muscular dystrophies.