Cytokines and alcohol

Cytokines are multifunctional proteins that play a critical role in cellular communication and activation. Cytokines have been classified as being proinflammatory (T helper 1, Th1) or anti-inflammatory (T helper 2, Th2) depending on their effects on the immune system. However, cytokines impact a variety of tissues in a complex manner that regulates inflammation, cell death, and cell proliferation and migration as well as healing mechanisms. Ethanol (alcohol) is known to alter cytokine levels in a variety of tissues including plasma, lung, liver, and brain. Studies on human monocyte responses to pathogens reveal ethanol disruption of cytokine production depending upon the pathogen and duration of alcohol consumption, with multiple pathogens and chronic ethanol promoting inflammatory cytokine production. In lung, cytokine production is disrupted by ethanol exacerbating respiratory distress syndrome with greatly increased expression of transforming growth factor beta (TGFbeta). Alcoholic liver disease involves an inflammatory hepatitis and an exaggerated Th1 response with increases in tumor necrosis factor alpha (TNFalpha). Recent studies suggest that the transition from Th1 to Th2 cytokines contribute to hepatic fibrosis and cirrhosis. Cytokines affect the brain and likely contribute to changes in the central nervous system that contribute to long-term changes in behavior and neurodegeneration. Together these studies suggest that ethanol disruption of cytokines and inflammation contribute in multiple ways to a diversity of alcoholic pathologies.     

Sequence type 1 group B Streptococcus,an emerging cause of invasive disease in adults,evolves by small genetic changes

The molecular mechanisms underlying pathogen emergence in humans is a critical but poorly understood area of microbiologic investigation. Serotype V group B Streptococcus (GBS) was first isolated from humans in 1975, and rates of invasive serotype V GBS disease significantly increased starting in the early 1990s. We found that 210 of 229 serotype V GBS strains (92%) isolated from the bloodstream of nonpregnant adults in the United States and Canada between 1992 and 2013 were multilocus sequence type (ST) 1. Elucidation of the complete genome of a 1992 ST-1 strain revealed that this strain had the highest homology with a GBS strain causing cow mastitis and that the 1992 ST-1 strain differed from serotype V strains isolated in the late 1970s by acquisition of cell surface proteins and antimicrobial resistance determinants. Whole-genome comparison of 202 invasive ST-1 strains detected significant recombination in only eight strains. The remaining 194 strains differed by an average of 97 SNPs. Phylogenetic analysis revealed a temporally dependent mode of genetic diversification consistent with the emergence in the 1990s of ST-1 GBS as major agents of human disease. Thirty-one loci were identified as being under positive selective pressure, and mutations at loci encoding polysaccharide capsule production proteins, regulators of pilus expression, and two-component gene regulatory systems were shown to affect the bacterial phenotype. These data reveal that phenotypic diversity among ST-1 GBS is mainly driven by small genetic changes rather than extensive recombination, thereby extending knowledge into how pathogens adapt to humans.The recent increase in large-scale DNA sequencing feasibility has allowed for significant advances in understanding the population genetics of bacteria that cause disease in humans (1, 2). A major outcome of the rapid expansion of available bacterial genomes has been the appreciation of the marked intraspecies genetic variability present in a wide variety of human bacterial pathogens (3, 4). This genetic variation can have profound impact on host–pathogen interaction by affecting transmissibility, infection severity, and antimicrobial resistance (2, 5, 6). The observed genetic intraspecies variability can arise via many distinct mechanisms including large-scale events such as recombination and bacteriophage-mediated horizontal gene transfer as well as small-scale genetic changes such as short insertions, deletions, and/or single nucleotide changes (2, 3, 5).Group B Streptococcus (GBS) is a common colonizer of humans that emerged in the 1970s as the leading cause of invasive bacterial disease in neonates and infants less than 3 mo of age (7). GBS is divided into 10 serotypes based on the carbohydrate composition of its sialic acid containing capsule, but gene content at the genomic level does not necessarily correlate with capsular serotype (8, 9). A seven-gene multilocus sequence typing (MLST) allows for the classification of the majority of GBS strains isolated from humans into five major clonal complexes (CCs) with a recent study by Da Cunha et al. showing that the major GBS CCs are primarily derived from a limited number of tetracycline-resistant clones, suggesting a key role of tetracycline resistance in GBS strain emergence (10, 11). CC-17 GBS strains have been particularly well studied given their role as the major cause of severe, invasive infant disease (10, 12). In contrast, serotype V strains cause a larger percentage of invasive disease in nonpregnant adults compared with neonates (13–15). Importantly, rates of invasive GBS disease have been increasing during the past 25 y in nonpregnant adults, with a significant part of the rise resulting from serotype V GBS strains (15–17).Despite the clear and increasing impact of serotype V strains, data are limited regarding molecular epidemiology of serotype V GBS causing invasive disease in nonpregnant adults (14, 15, 18). Only a few studies of serotype V strains have investigated the noncapsular genetic makeup of the strains, and those that have done so have included colonizing and invasive GBS strains isolated from infants or have not described the clinical origin of the tested strains (18, 19). Thus, we sought to analyze a large cohort of clinically well-defined, geographically distinct, and temporally disparate GBS isolates by using a whole-genome approach to elucidate the population structure of serotype V GBS causing invasive disease in nonpregnant adults. Data using non–genome-wide level approaches found that many serotype V strains were closely related, suggesting that a particular clone, rather than a genetically diverse array of strains arising from large-scale recombination, might be responsible for the majority of serotype V disease (18). Thus, we specifically sought to test the hypothesis that genetic diversity among invasive serotype V GBS strains is driven by small genetic changes at loci that are critical to GBS host–pathogen interaction.     

Immunity and inflammatory signaling in alcoholic liver disease

The pathogenesis of alcoholic liver disease (ALD) is multifactorial and characterized by steatosis, steatohepatitis and cirrhosis. Several signaling pathways in different liver cell types that contribute to the development and progression of alcoholic liver injury have been identified. Among these, immune cells and signaling pathways are the most prominent and central to ALD. Both innate and adaptive immune responses contribute to ALD. The key features of inflammatory pathways in ALD including liver innate and adaptive immune cell types, signaling receptors/pathways, and pro- and antiinflammatory/protective responses are summarized here.     

A critical review on Nepal Dock(Rumex nepalensis):A tropical herb with immense medicinal importance

Rumex nepalensis Spreng.(Polygonaceae) commonly known as Nepal Dock has wide-spectrum therapeutic potencies and is extensively used for centuries in traditional medicine systems. The leaves of this plant are edible and a rich source of natural antioxidants. They act as a possible food supplement and are largely used in pharmaceutical industry. Extracts and metabolites from this plant exhibits pharmacological activities including anti-inflammatory, antioxidant, antibacterial, antifungal, antiviral, insecticidal, purgative, analgesic, antipyretic, anti-algal, central nervous system depressant, genotoxic, wound healing and skeletal muscle relaxant activity. Due to its remarkable biological activities, it has the potential to act as a rich source of drug against life threatening diseases. However, more studies are needed to scientifically validate the traditional uses of this plant, beside isolating and identifying their active principles and characterizing the mechanisms of action. We present herein a critical account of its botany, ecology, traditional uses, phytoconstituent profile and major pharmacological activities reported in recent years and therefore will provide a source of information on this plant for further studies.     

Selective priming to Toll-like receptor 4 (TLR4), not TLR2, ligands by P. acnes involves up-regulation of MD-2 in mice

Lipopolysaccharide (LPS) triggers cytokine production through Toll-like receptor 4 (TLR4), which shares downstream signaling pathways with TLR2. We investigated the roles of TLR2 and TLR4 in Propionibacterium acnes (P. acnes)-primed, LPS-induced liver damage using selective TLR ligands. Stock LPS induced interleukin 8 in both TLR4- and TLR2-expressing human embryonic kidney (HEK) 293 cells. Purified LPS (TLR4 ligand) activated HEK/TLR4 cells, while peptidoglycan and lipoteichoic acid (TLR2 ligands) activated HEK/TLR2 cells, respectively. In mice, P. acnes priming resulted in increased liver messenger RNA (mRNA) and serum levels of tumor necrosis factor alpha, interleukin 12, and interferon gamma (IFN-gamma) by both stock LPS and purified LPS challenges compared with nonprimed controls. In contrast, P. acnes failed to sensitize to TLR2 ligands (peptidoglycan + lipoteichoic acid). In the liver, P. acnes-priming was associated with up-regulation of TLR4 and MD-2 proteins, and subsequent LPS challenge further increased MD-2 and CD14 mRNA levels. The lack of sensitization to TLR2 ligands by P. acnes correlated with no increase in hepatic TLR1 or TLR6 mRNA. In vitro, P. acnes pretreatment desensitized RAW macrophages to a secondary stimulation via both TLR2 and TLR4. However, IFN-gamma could selectively prevent desensitization to TLR4 but not to TLR2 ligands. Furthermore, P. acnes induced production of IFN-gamma in vivo as well as in isolated splenocytes. In vitro, P. acnes-primed Hepa 1-6 hepatocytes but not RAW macrophages produced increased MD-2 and CD14 mRNA levels after an LPS challenge. In conclusion, P. acnes priming to selective TLR4-mediated liver injury is associated with up-regulation of TLR4 and MD-2 and is likely to involve IFN-gamma and prevent TLR4 desensitization by P. acnes.     

Acute ethanol treatment modulates Toll-like receptor-4 association with lipid rafts

BACKGROUND: Alcohol, a substance that is most frequently abused, suppresses innate immune responses to microbial pathogens. The host senses pathogens via Toll-like receptors (TLRs). Recent studies indicate that alcohol affects TLR signaling. METHODS: Here, we hypothesized that acute alcohol treatment may interfere with early steps of membrane-associated TLR2 and TLR4 signaling at the level of lipid rafts. Human monocytes and Chinese hamster ovary (CHO) cells, transfected with human TLR2, TLR4, or CD14, were stimulated with peptidoglycan (PGN, TLR2 ligand) or lipopolysaccharide (LPS, TLR4 ligand) with or without alcohol (50 mM) and analyzed for cytokine production (enzyme-linked immunosorbent assay), nuclear factor-kappaB (NF-kappaB) activation (electrophoretic mobility shift assay), membrane fluidity (fluorescent pyrene eximer formation), and partition of cellular membrane into cholesterol-rich, detergent-resistant domains (DRMs; Western blot). RESULTS: We determined that both TLR2 and TLR4 were located outside the rafts; flotillin, a DRM marker, was resident in the rafts, while CD14 was equally distributed in and outside the rafts in a steady-state condition. PGN forced TLR2 to migrate into DRMs. Engagement of TLR4 and CD14 with LPS induced their migration into the rafts. Alcohol prevented TLR4 partitioning; however, it did not affect TLR2 migration into the rafts. Furthermore, alcohol downregulated TLR4-induced, but not TLR2-induced, NF-kappaB activation and cytokine production in monocytes. We found that alcohol increased membrane fluidity and depleted cellular cholesterol in CHO cells without affecting cell viability. CONCLUSIONS: These data demonstrate for the first time that alcohol disturbs TLR4 and CD14 association with lipid rafts. We propose that alcohol-induced effects on lipid rafts may contribute to modulation of TLR4-CD14-triggered early cellular responses.