Foam cell formation from macrophages with subsequent fatty streak formation plays a key role in early atherogenesis. Foam cell formation is thought to be induced by Low Density Lipoproteins (LDL), including oxidized LDL (OxLDL) or minimally modified LDL (mmLDL). Understanding the molecular mechanisms involved in OxLDL-and mmLDL-induced foam cell formation is of fundamental importance for atherosclerosis and cardiovascular disease. The expression of many genes is likely modulated during macrophage transformation into a foam cell. In this mini-review we describe functional consequences of modulation of three groups of genes: Scavenger Receptors (SR-A, CLA-1/SR-BI, CD36, CD68, LOX-1, and SR-PSOX), the PPAR family of nuclear receptors, and a number of genes involved in eicosanoid biosynthesis, including lipoxygenases and leukotriene receptors. Scavenger receptors appear to play a key role in uptake of OxLDL, while mmLDL appears to interact with CD14/TLR4. The regulation of scavenger receptors is, in part, mediated by the PPAR family of nuclear receptors. PPARα and PPARγ agonists, such as thiazolidinediones and fibrates, and PPARδ agonists were tested as atheroprotective drugs and showed some beneficial effects. Eicosanoids are naturally occuring agonists for PPARs. Recent observations indicate a role of the components of the eicosanoid cascade, such as 5-lipoxygenase, 15-lipoxygenase and the leukotriene receptors in foam cell formation. Selective inhibitors of lipoxygenases and leukotriene receptors could be useful in the treatment of atherosclerosis by preventing or reducing foam cell formation.

Platelets express TLR4 receptors, but its ligand LPS does not directly activate thrombotic functions nor, obviously, transcription by these anucleate cells. Platelets, however, store information that changes their phenotype over a few hours in the form of unprocessed RNA transcripts. We show even low concentrations of LPS in the presence of soluble CD14 initiated splicing of unprocessed IL-1β RNA, with translation and accumulation of IL-1β protein. LPS was a more robust agonist for this response than thrombin. Platelets also contained cyclooxygenase-2 pre-mRNA, which also was spliced and translated after LPS stimulation. Flow cytometry and immunocytochemistry of platelets extensively purified by negative immunodepletion showed platelets contained IL-1β, and quantitative assessment of white blood cell contamination by CD14 real time PCR confirms that leukocytes were not the IL-1β source, nor were they required for platelet stimulation. LPS did not initiate rapid platelet responses, but over time did prime platelet aggregation to soluble agonists, induced actin rearrangement, and initiated granule secretion with P-selectin expression that resulted the coating of quiescent leukocytes with activated platelets. LPS is a direct agonist for platelets that allows these cells to directly participate in the innate immune response to bacteria.

Background-Mice

Foam cell formation from monocyte-derived macrophages is a hallmark of atherosclerotic lesions. Aspects of this process can be recapitulated in vitro by exposing M-CSF-induced or platelet factor 4 (CXCL4)-induced macrophages to oxidized (ox) or minimally modified (mm) low density lipoprotein (LDL). We measured gene expression in peripheral blood mononuclear cells, monocytes, and macrophages treated with CXCL1 (GRO-alpha) or CCL2 (MCP-1), as well as foam cells induced by native LDL, mmLDL, or oxLDL using 22 Affymetrix gene chips. Using an advanced Bayesian error-pooling approach and a heterogeneous error model with a false discovery rate <0.05, we found 5,303 of 22,215 probe sets to be significantly regulated in at least one of the conditions. Among a subset of 917 candidate genes that were preselected for their known biological functions in macrophage foam-cell differentiation, we found that 290 genes met the above statistical criteria for significant differential expression patterns. While many expected genes were found to be upregulated by LDL and oxLDL, very few were induced by mmLDL. We also found induction of unexpected genes, most strikingly MHC-II and other dendritic cell markers such as CD11c. The gene expression patterns in response to oxLDL were similar in M-CSF-induced and CXCL4-induced macrophages. Our findings suggest that LDL and oxLDL, but not mmLDL, induce a dendritic cell-like phenotype in macrophages, suggesting that these cells may be able to present antigens and support an immune response.

Data on the chemical composition and pharmacological activity of chaga (Inonotus obliquus) are reviewed. The possible mechanisms of action and factors responsible for the discrepancy of data available in the literature are discussed. The physical and chemical characteristics of melanin (polyphenolic chromogenic humin-like complex present in chaga) and its role in the regulation of physiological processes are considered.The curative properties of chaga have been known from ancient times. Despite many ages of use in folk medicine and a broad spectrum of biological action, chaga has found only restricted use in the officinal medicine. Numerous attempts to elucidate the therapeutic potential of chaga preparations for the prophylaxis and treatment of cancer and other disorders gave rather ambiguous results. This review presents an attempt at systematizing available published data on the chemical nature of components isolated from chaga, their pharmacological activity, and the mechanism of biological action.According to the botanic classification, Chaga -also known as birch fungus (Fungus betulinus) -represent terrestrial polypore fungi Inonotus obliquus (Fr.) Pil of Polyporaceae (or Gymenochaetaceae) family belonging to Basidiomycota phylum (basidiomycetes) [1,2]. About 25000 species of basidiomycetes have been described, including about 500 polypore fungi that are widely occurring in Europe, Asia, North America, and Africa. However, only a small fraction of these species have been evaluated with respect to biological properties, of which 75% show strong antimicrobial activity, and these may constitute a good source for developing new antibiotics. These fungi contain numerous components exhibiting antiviral, cytotoxic, immunomodulatory, antidiabetic, and antioxidant properties. In Japan, some of the protein-bound polysaccharides from polypores and other basidiomycetes have found their way into the market as anticancer drugs [3].In Russia, Poland, and Belarus, medicinal preparations are more frequently made of chaga (birch fungus) [1, 2, 4], which represents a product of the fruitless (sterile) stage of development of a wood-destroying fungus parasitizing on trunks, mostly of birch and less frequently of alder, witchen, and bird cherry. Chaga is a shapeless formation [2, 4], differing from the fruiting body (basidiocarp) of a polypore that typically has a hoof shape. The cycle of birch fungus development and the formation of chaga have unique features. Basidiospores of Inonotus obliquus spread in air to fall onto damaged sites of the crust of living birch trees (frost-induced damage, broken branches, etc.), grow into the wood, and form a mycelium that consumes the plant juice. The threads (hyphae) of mycelium penetrate into the wood, destroy it, and lead to the formation of a structureless white touchwood. Simultaneously, a fruiting body (basidiocarp) producing spores is formed under the crust (at the sites of initial penetration). On the fourth year, this mycelium emerges at the crust surface, where the fruitless myce...

The role of calmodulin in control of carbohydrate metabolism in the absence and presence of insulin in isolated mouse soleus muscle was investigated. The calmodulin antagonist CGS 9343B had no effect on basal glycogen synthase activity, the contents of high energy phosphates, glucose-6-P, or glycogen synthesis. However, CGS 9343B inhibited the basal rates of 2-deoxyglucose uptake and 3-O-methylglucose transport by 30% (p < 0.05) and 40% (p < 0.001), respectively. Insulin activated glycogen synthase by almost 40% (p < 0.01) and this increase was not altered in the presence of CGS 9343B. Insulin increased the muscle content of glucose-6-P (Ϸ2-fold), as well as glycogen synthesis (Ϸ8-fold), 2-deoxyglucose uptake (Ϸ3-fold), and 3-O-methylglucose transport (Ϸ2-fold), and these increases were inhibited by CGS 9343B. In additional experiments on isolated rat epitrochlearis muscle, it was found that the hypoxiamediated activation of 3-O-methylglucose transport was also inhibited by CGS 9343B. These data demonstrate that: 1) hexose transport, both in the absence and presence of external stimuli (insulin and hypoxia), requires functional calmodulin; and 2) insulin-mediated activation of glycogen synthase does not require functional calmodulin, nor can it be accounted for by increases in glucose transport or glucose-6-P.

Insulin generates/releases chemical substances that alter the activities of purified enzymes [1,2] and the metabolism of intact cells [3,4] in an insulin mimetic fashion. These substances have therefore been termed mediators or second messengers of insulin [5]. Two different insulin mediators have been separated from rat liver [6]. These mediators have been identified as inositol phosphoglycans (IPGs), containing inositol, non-acetylated amino sugars, neutral sugars, ethanolamine, phosphate and, possibly, amino acids [5]. One contains d -chiro-inositol and activates pyruvate dehydrogenase (PDH) phosphatase, whereas another contains myo-inositol and inhibits cyclic AMP-dependent protein kinase (PKA). Injection of each of these IPGs into low-dose streptozotocin-diabetic rats lowers blood glucose [7].Body fluids of patients with non-insulin-dependent diabetes mellitus (NIDDM) have abnormally low levels of Summary Insulin mediators (inositol phosphoglycans) have been shown to mimic insulin action in vitro and in intact mammals, but it is not known which mediator is involved in insulin action under physiological conditions, nor is it known whether insulin resistance alters the mediator profile under such conditions. We therefore investigated the effects of glucose ingestion on changes in the bioactivity of serum inositol phosphoglycan-like substances (IPG) in healthy men and insulin resistant (obese, non-insulin-dependent diabetic) men. Two classes of mediators were partially purified from serum before and after glucose ingestion. The first was eluted from an anion exchange resin with HCl pH 2.0, and bioactivity was determined by activation of pyruvate dehydrogenase in vitro. The second was eluted with HCl pH 1.3, and bioactivity was determined by inhibition of cyclic AMP-dependent protein kinase. In healthy men, the bioactivity of the pH 1.3 IPG was not altered by glucose ingestion, whereas bioactivity of the pH 2.0 IPG increased to approximately 120 % of the pre-glucose ingestion value at 60-240 min post-glucose ingestion (p < 0.05 vs pre-glucose). There was no change in either IPG after glucose ingestion in the insulin-resistant group. These data suggest that the pH 2.0 IPG plays an important role in mediating insulin's effect on peripheral glucose utilization in man under physiological conditions. The data further show, for the first time, a defective change in the bioactivity of an insulin mediator isolated from insulin-resistant humans after hyperinsulinaemia, suggesting that inadequate generation/release of IPGs is associated with insulin resistance. [Diabetologia (1997) 40: 557-563] Keywords Inositol phosphoglycans, non-insulin dependent diabetes mellitus, pyruvate dehydrogenase, cyclic AMP dependent protein kinase.

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