Edible blue-green algae reduce the production of pro-inflammatory cytokines by inhibiting NF-κB pathway in macrophages and splenocytes

Background

Chronic inflammation contributes to the development of pathological disorders including insulin resistance and atherosclerosis. Identification of anti-inflammatory natural products can prevent the inflammatory diseases.

Methods

Anti-inflammatory effects of blue-green algae (BGA), i.e., Nostoc commune var. sphaeroides Kützing (NO) and Spirulina platensis (SP), were compared in RAW 264.7 and mouse bone marrow-derived macrophages (BMM) as well as splenocytes from apolipoprotein E knockout (apoE^−/−) mice fed BGA.

Results

When macrophages pretreated with 100 μg/ml NO lipid extract (NOE) or SP lipid extract (SPE) were activated by lipopolysaccharide (LPS), expression and secretion of pro-inflammatory cytokines, such as tumor necrosis factor α (TNFα), interleukin 1β (IL-1β), and IL-6, were significantly repressed. NOE and SPE also significantly repressed the expression of TNFα and IL-1β in BMM. LPS-induced secretion of IL-6 was lower in splenocytes from apoE^−/− fed an atherogenic diet containing 5% NO or SP for 12 weeks. In RAW 264.7 macrophages, NOE and SPE markedly decreased nuclear translocation of NF-κB. The degree of repression of pro-inflammatory gene expression by algal extracts was much stronger than that of SN50, an inhibitor of NF-κB nuclear translocation. Trichostatin A, a pan histone deacetylase inhibitor, increased basal expression of IL-1β and attenuated the repression of the gene expression by SPE. SPE significantly down-regulated mRNA abundance of 11 HDAC isoforms, consequently increasing acetylated histone 3 levels.

Conclusion

NOE and SPE repress pro-inflammatory cytokine expression and secretion in macrophages and splenocytes via inhibition of NF-κB pathway. Histone acetylation state is likely involved in the inhibition.

General significance

This study underscores natural products can exert anti-inflammatory effects by epigenetic modifications such as histone acetylation.     

Dendrocalamus longiligulatus sp. nov. (Poaceae: Bambusoideae) from Son La,Dien Bien province,Vietnam

A new species of Dendrocalamus, D. longiligulatus N. H. Xia & V. T. Nguyen, is described and illustrated. This species is distinguished from D. pachystachys Hsueh & D. Z. Li and D. jianshuiensis Hsueh & D. Z. Li by its inconspicuous culm sheath auricles, margins with 8–10 mm long fimbriations, fimbriate ligules of culm sheath 11–14 mm long, palea with 3 veins between and 1 vein on either side of the keels, and blunt paleaceous apex.     

Injections,Cocktails and Diviners: Therapeutic Flexibility in the Context of Malaria Elimination and Drug Resistance in Northeast Cambodia

Background

Adherence to effective malaria medication is extremely important in the context of Cambodia’s elimination targets and drug resistance containment. Although the public sector health facilities are accessible to the local ethnic minorities of Ratanakiri province (Northeast Cambodia), their illness itineraries often lead them to private pharmacies selling “cocktails” and artemether injections, or to local diviners prescribing animal sacrifices to appease the spirits.

Methods

The research design consisted of a mixed methods study, combining qualitative (in-depth interviews and participant observation) and quantitative methods (household and cross-sectional survey).

Results

Three broad options for malaria treatment were identified: i) the public sector; ii) the private sector; iii) traditional treatment based on divination and ceremonial sacrifice. Treatment choice was influenced by the availability of treatment and provider, perceived side effects and efficacy of treatments, perceived etiology of symptoms, and patient-health provider encounters. Moreover, treatment paths proved to be highly flexible, changing mostly in relation to the perceived efficacy of a chosen treatment.

Conclusions

Despite good availability of anti-malarial treatment in the public health sector, attendance remained low due to both structural and human behavioral factors. The common use and under-dosage of anti-malaria monotherapy in the private sector (single-dose injections, single-day drug cocktails) represents a threat not only for individual case management, but also for the regional plan of drug resistance containment and malaria elimination.     

Genetic status of Asiatic black bear (Ursus thibetanus) reintroduced into South Korea based on mitochondrial DNA and microsatellite loci analysis

The Asiatic black bear is one of the most endangered mammals in South Korea owing to population declines resulting from human exploitation and habitat fragmentation. To restore the black bear population in South Korea, 27 bear cubs from North Korea and Russian Far East (Primorsky Krai) were imported and released into Jirisan National Park, a reservoir of the largest wild population in South Korea, in 2004. To monitor the success of this reintroduction, the genetic diversity and population structure of the reintroduced black bears were measured using both mitochondrial and nuclear DNA markers. Mitochondrial D-loop region DNA sequences (615 bp) of 43 Japanese black bears from previous study and 14 Southeast Asian black bears in this study were employed to obtain phylogenetic inference of the reintroduced black bears. The mitochondrial phylogeny indicated Asiatic black bear populations from Russian Far East and North Korea form a single evolutionary unit distinct from populations from Japan and Southeast Asia. Mean expected heterozygosity (H(E)) across 16 microsatellite loci was 0.648 for Russian and 0.676 for North Korean populations. There was a moderate but significant level of microsatellite differentiation (F(ST) = 0.063) between black bears from the 2 source areas. In addition, genetic evidences revealed that 2 populations are represented as diverging groups, with lingering genetic admixture among individuals of 2 source populations. Relatedness analysis based on genetic markers indicated several discrepancies with the pedigree records. Implication of the phylogenetic and genetic evidences on long-term management of Asiatic black bears in South Korea is discussed.     

Distinct transthyretin oxidation isoform profile in spinal fluid from patients with Alzheimer’s disease and mild cognitive impairment

Background

Transthyretin (TTR), an abundant protein in cerebrospinal fluid (CSF), contains a free, oxidation-prone cysteine residue that gives rise to TTR isoforms. These isoforms may reflect conditions in vivo. Since increased oxidative stress has been linked to neurodegenerative disorders such as Alzheimer’s disease (AD) it is of interest to characterize CSF-TTR isoform distribution in AD patients and controls. Here, TTR isoforms are profiled directly from CSF by an optimized immunoaffinity-mass spectrometry method in 76 samples from patients with AD (n = 37), mild cognitive impairment (MCI, n = 17)), and normal pressure hydrocephalus (NPH, n = 15), as well as healthy controls (HC, n = 7). Fractions of three specific oxidative modifications (S-cysteinylation, S-cysteinylglycinylation, and S-glutathionylation) were quantitated relative to the total TTR protein. Results were correlated with diagnostic information and with levels of CSF AD biomarkers tau, phosphorylated tau, and amyloid β_1-42 peptide.

Results

Preliminary data highlighted the high risk of artifactual TTR modification due to ex vivo oxidation and thus the samples for this study were all collected using strict and uniform guidelines. The results show that TTR is significantly more modified on Cys(10) in the AD and MCI groups than in controls (NPH and HC) (p ≤ 0.0012). Furthermore, the NPH group, while having normal TTR isoform distribution, had significantly decreased amyloid β peptide but normal tau values. No obvious correlations between levels of routine CSF biomarkers for AD and the degree of TTR modification were found.

Conclusions

AD and MCI patients display a significantly higher fraction of oxidatively modified TTR in CSF than the control groups of NPH patients and HC. Quantitation of CSF-TTR isoforms thus may provide diagnostic information in patients with dementia symptoms but this should be explored in larger studies including prospective studies of MCI patients. The development of methods for simple, robust, and reproducible inhibition of in vitro oxidation during CSF sampling and sample handling is highly warranted. In addition to the diagnostic information the possibility of using TTR as a CSF oxymeter is of potential value in studies monitoring disease activity and developing new drugs for neurodegenerative diseases.     

Shear-induced endothelial mechanotransduction: the interplay between reactive oxygen species (ROS) and nitric oxide (NO) and the pathophysiological implications

Hemodynamic shear stress, the blood flow-generated frictional force acting on the vascular endothelial cells, is essential for endothelial homeostasis under normal physiological conditions. Mechanosensors on endothelial cells detect shear stress and transduce it into biochemical signals to trigger vascular adaptive responses. Among the various shear-induced signaling molecules, reactive oxygen species (ROS) and nitric oxide (NO) have been implicated in vascular homeostasis and diseases. In this review, we explore the molecular, cellular, and vascular processes arising from shear-induced signaling (mechanotransduction) with emphasis on the roles of ROS and NO, and also discuss the mechanisms that may lead to excessive vascular remodeling and thus drive pathobiologic processes responsible for atherosclerosis. Current evidence suggests that NADPH oxidase is one of main cellular sources of ROS generation in endothelial cells under flow condition. Flow patterns and magnitude of shear determine the amount of ROS produced by endothelial cells, usually an irregular flow pattern (disturbed or oscillatory) producing higher levels of ROS than a regular flow pattern (steady or pulsatile). ROS production is closely linked to NO generation and elevated levels of ROS lead to low NO bioavailability, as is often observed in endothelial cells exposed to irregular flow. The low NO bioavailability is partly caused by the reaction of ROS with NO to form peroxynitrite, a key molecule which may initiate many pro-atherogenic events. This differential production of ROS and RNS (reactive nitrogen species) under various flow patterns and conditions modulates endothelial gene expression and thus results in differential vascular responses. Moreover, ROS/RNS are able to promote specific post-translational modifications in regulatory proteins (including S-glutathionylation, S-nitrosylation and tyrosine nitration), which constitute chemical signals that are relevant in cardiovascular pathophysiology. Overall, the dynamic interplay between local hemodynamic milieu and the resulting oxidative and S-nitrosative modification of regulatory proteins is important for ensuing vascular homeostasis. Based on available evidence, it is proposed that a regular flow pattern produces lower levels of ROS and higher NO bioavailability, creating an anti-atherogenic environment. On the other hand, an irregular flow pattern results in higher levels of ROS and yet lower NO bioavailability, thus triggering pro-atherogenic effects.     

alpha-N-acetylgalactosamine-capping of chondroitin sulfate core region oligosaccharides primed on xylosides

We previously reported that cultured mammalian cells incubated with 4- methylumbelliferyl (MU) or p -nitrophenyl (pNP) beta-xyloside synthesize an alpha-GalNAc-terminated pentasaccharide resembling the glycosaminoglycan-core protein linkage region. Here we show that human melanoma M21 cells and human neuroblastoma cells incubated with Xylbeta- MU/pNP also make an alpha-GalNAc-terminated heptasaccharide containing one chondroitin disaccharide repeat. High performance liquid chromatography and matrix-assisted laser desorption ionization mass spectrometry analysis of intact or glycosidase-digested xyloside showed the structure as: GalNAcalphaGlcAbeta1,3GalNAcbeta1,4GlcAbeta1,3Galbe ta1,3Galbeta1, 4Xylbeta-MU/pNP. The alpha-GalNAc-terminated xylosides can account for approximately 10% of the total Xylbeta-MU/pNP products ( approximately 1.5 nmol/h/mg). These results show that GalNAcalphaGlcAbeta-modification is relatively abundant, but not unique to the GAG-linkage tetrasaccharide. alpha-GalNAc addition to the GlcA residue does not appear to be an extension of general phase II detoxification of xenobiotics that involve glucuronidation, since M21 cells incubated with MU synthesize only 0.3 pmol GlcAbeta-MU/h/mg protein, and undetectable amount of GalNAcalphaGlcAbeta-MU (<40 fmol/h/mg). Further, subcellular fractionation shows that the alpha- N- acetylgalactosaminyltransferase activity colocalizes in the Golgi with other glycosyl transferases and not in the ER, where xenobiotic detoxification glucuronosyltransferases are found. Although GalNAcalphaGlcAbeta-terminal modification has not been detected on naturally occurring GAG chains, the substantial amount of alpha-GalNAc transferase activity suggests that the alpha-GalNAc transferase could utilize other GlcA-containing glycoconjugates as acceptors.      

Vascular dysfunction in aged mice contributes to persistent lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive disease thought to result from impaired lung repair following injury and is strongly associated with aging. While vascular alterations have been associated with IPF previously, the contribution of lung vasculature during injury resolution and fibrosis is not well understood. To compare the role of endothelial cells (ECs) in resolving and non‐resolving models of lung fibrosis, we applied bleomycin intratracheally to young and aged mice. We found that injury in aged mice elicited capillary rarefaction, while injury in young mice resulted in increased capillary density. ECs from the lungs of injured aged mice relative to young mice demonstrated elevated pro‐fibrotic and reduced vascular homeostasis gene expression. Among the latter, Nos3 (encoding the enzyme endothelial nitric oxide synthase, eNOS) was transiently upregulated in lung ECs from young but not aged mice following injury. Young mice deficient in eNOS recapitulated the non‐resolving lung fibrosis observed in aged animals following injury, suggesting that eNOS directly participates in lung fibrosis resolution. Activation of the NO receptor soluble guanylate cyclase in human lung fibroblasts reduced TGFβ‐induced pro‐fibrotic gene and protein expression. Additionally, loss of eNOS in human lung ECs reduced the suppression of TGFβ‐induced lung fibroblast activation in 2D and 3D co‐cultures. Altogether, our results demonstrate that persistent lung fibrosis in aged mice is accompanied by capillary rarefaction, loss of EC identity, and impaired eNOS expression. Targeting vascular function may thus be critical to promote lung repair and fibrosis resolution in aging and IPF.     

Population density, water supply, and the risk of dengue fever in Vietnam: cohort study and spatial analysis

Background

Aedes aegypti, the major vector of dengue viruses, often breeds in water storage containers used by households without tap water supply, and occurs in high numbers even in dense urban areas. We analysed the interaction between human population density and lack of tap water as a cause of dengue fever outbreaks with the aim of identifying geographic areas at highest risk.

Methods and Findings

We conducted an individual-level cohort study in a population of 75,000 geo-referenced households in Vietnam over the course of two epidemics, on the basis of dengue hospital admissions (n = 3,013). We applied space-time scan statistics and mathematical models to confirm the findings. We identified a surprisingly narrow range of critical human population densities between around 3,000 to 7,000 people/km² prone to dengue outbreaks. In the study area, this population density was typical of villages and some peri-urban areas. Scan statistics showed that areas with a high population density or adequate water supply did not experience severe outbreaks. The risk of dengue was higher in rural than in urban areas, largely explained by lack of piped water supply, and in human population densities more often falling within the critical range. Mathematical modeling suggests that simple assumptions regarding area-level vector/host ratios may explain the occurrence of outbreaks.

Conclusions

Rural areas may contribute at least as much to the dissemination of dengue fever as cities. Improving water supply and vector control in areas with a human population density critical for dengue transmission could increase the efficiency of control efforts. Please see later in the article for the Editors'' Summary