Carotenoids from Starfish Patiria pectinifera: Therapeutic Activity in Models of Inflammatory Diseases.

The carotenoids mixture (MC) isolated from the starfish Patiria. pectinifera contains more than 50% astaxanthin, 4-6% each zeaxanthine and lutein, and less pharmacologically active components such as free fatty acids and their glycerides. Astaxanthin, the major component of MC, belongs to the xanthophyll class of carotenoids, and is well known for its antioxidant properties. In this work, in vitro and in vivo studies on the biological activity of MC were carried out. The complex was shown to exhibit anti-inflammatory, anti-allergic and cancer-preventive activity, without any toxicity at a dose of 500 mg/kg. MC effectively improves the clinical picture of the disease progressing, as well as normalizing the cytokine profile and the antioxidant defense system in the in vivo animal models of inflammatory diseases, namely: skin carcinogenesis, allergic contact dermatitis (ACD) and systemic inflammation (SI). In the skin carcinogenesis induced by 7,12-dimethylbenzanthracene, the incidence of papillomas was decreased 1.5 times; 1% MC ointment form in allergic contact dermatitis showed an 80% reduced severity of pathomorphological skin manifestations. Obtained results show that MC from starfish P. pectinifera is an effective remedy for the treatment and prevention of inflammatory processes.

Comparative Study of the Pharmacological Properties of Luteolin and Its 7,3'-Disulfate.

The global spread of the metabolic syndrome, oncological and viral diseases forces researchers to pay increased attention to the secondary metabolites of marine hydrobionts, which often have a high therapeutic potential in the treatment of these pathologies and are effective components of functional food. The flavone luteolin (LT), as one of the most widely distributed and studied plant metabolites, is distinguished by a diverse spectrum of biological activity and a pleiotropic nature of the mechanism of action at the molecular, cellular and organismal levels. However, there is still practically no information on the spectrum of biological activity of its sulfated derivatives, which are widely represented in seagrasses of the genus Zostera. In the present work, a comparative study of the pharmacological properties of LT and its 7,3'-disulfate was carried out with a brief analysis of the special role of sulfation in the pharmacological activity of flavonoids.

Nicotinic Acetylcholine Receptors Are Novel Targets of APETx-like Toxins from the Sea Anemone Heteractis magnifica.

The nicotinic acetylcholine receptors (nAChRs) are prototypical ligand-gated ion channels, provide cholinergic signaling, and are modulated by various venom toxins and drugs in addition to neurotransmitters. Here, four APETx-like toxins, including two new toxins, named Hmg 1b-2 Metox and Hmg 1b-5, were isolated from the sea anemone Heteractis magnifica and characterized as novel nAChR ligands and acid-sensing ion channel (ASIC) modulators. All peptides competed with radiolabeled α-bungarotoxin for binding to Torpedo californica muscle-type and human α7 nAChRs. Hmg 1b-2 potentiated acetylcholine-elicited current in human α7 receptors expressed in Xenopus laevis oocytes. Moreover, the multigene family coding APETx-like peptides library from H. magnifica was described and in silico surface electrostatic potentials of novel peptides were analyzed. To explain the 100% identity of some peptide isoforms between H. magnifica and H. crispa, 18S rRNA, COI, and ITS analysis were performed. It has been shown that the sea anemones previously identified by morphology as H. crispa belong to the species H. magnifica.

Marine Polyhydroxynaphthoquinone, Echinochrome A: Prevention of Atherosclerotic Inflammation and Probable Molecular Targets.

The effect of low doses of echinochrome A (EchA), a natural polyhydroxy-1,4-naphthoquinone pigment from the sea urchin Scaphechinus mirabilis, has been studied in clinical trials, when it was used as an active substance of the drug Histochrome® and biologically active supplement Thymarin. Several parameters of lipid metabolism, antioxidant status, and the state of the immune system were analyzed in patients with cardiovascular diseases (CVD), including contaminating atherosclerosis. It has been shown that EchA effectively normalizes lipid metabolism, recovers antioxidant status and reduces atherosclerotic inflammation, regardless of the method of these preparations' administrations. Treatment of EchA has led to the stabilization of patients, improved function of the intracellular matrix and decreased epithelial dysfunction. The increased expression of surface human leukocyte antigen DR isotype (HLA-DR) receptors reflects the intensification of intercellular cooperation of immune cells, as well as an increase in the efficiency of processing and presentation of antigens, while the regulation of CD95 + expression levels suggests the stimulation of cell renewal processes. The immune system goes to a different level of functioning. Computer simulations suggest that EchA, with its aromatic structure of the naphthoquinone nucleus, may be a suitable ligand of the cytosolic aryl cell receptor, which affects the response of the immune system and causes the rapid expression of detoxification enzymes such as CYP and DT diaphorase, which play a protective role with CVD. Therefore, EchA possesses not only an antiradical effect and antioxidant activity, but is also a SOD3 mimetic, producing hydrogen peroxide and controlling the expression of cell enzymes through hypoxia-inducible factors (HIF), peroxisome proliferator-activated receptors (PPARs) and aryl hydrocarbon receptor (AhR).

APETx-Like Peptides from the Sea Anemone Heteractis crispa, Diverse in Their Effect on ASIC1a and ASIC3 Ion Channels.

Currently, five peptide modulators of acid-sensing ion channels (ASICs) attributed to structural class 1b of sea anemone toxins have been described. The APETx2 toxin is the first and most potent ASIC3 inhibitor, so its homologs from sea anemones are known as the APETx-like peptides. We have discovered that two APETx-like peptides from the sea anemone Heteractis crispa, Hcr 1b-3 and Hcr 1b-4, demonstrate different effects on rASIC1a and rASIC3 currents. While Hcr 1b-3 inhibits both investigated ASIC subtypes with IC50 4.95 ± 0.19 µM for rASIC1a and 17 ± 5.8 µM for rASIC3, Hcr 1b-4 has been found to be the first potentiator of ASIC3, simultaneously inhibiting rASIC1a at similar concentrations: EC50 1.53 ± 0.07 µM and IC50 1.25 ± 0.04 µM. The closest homologs, APETx2, Hcr 1b-1, and Hcr 1b-2, previously demonstrated the ability to inhibit hASIC3 with IC50 63 nM, 5.5, and 15.9 µM, respectively, while Hcr 1b-2 also inhibited rASIC1a with IC50 4.8 ± 0.3 µM. Computer modeling allowed us to describe the peculiarities of Hcr 1b-2 and Hcr 1b-4 interfaces with the rASIC1a channel and the stabilization of the expanded acidic pocket resulting from peptides binding which traps the rASIC1a channel in the closed state.

New Insights into the Type II Toxins from the Sea Anemone Heteractis crispa.

Toxins modulating NaV channels are the most abundant and studied peptide components of sea anemone venom. Three type-II toxins, δ-SHTX-Hcr1f (= RpII), RTX-III, and RTX-VI, were isolated from the sea anemone Heteractis crispa. RTX-VI has been found to be an unusual analog of RTX-III. The electrophysiological effects of Heteractis toxins on nine NaV subtypes were investigated for the first time. Heteractis toxins mainly affect the inactivation of the mammalian NaV channels expressed in the central nervous system (NaV1.1-NaV1.3, NaV1.6) as well as insect and arachnid channels (BgNaV1, VdNaV1). The absence of Arg13 in the RTX-VI structure does not prevent toxin binding with the channel but it has changed its pharmacological profile and potency. According to computer modeling data, the δ-SHTX-Hcr1f binds within the extracellular region of the rNaV1.2 voltage-sensing domain IV and pore-forming domain I through a network of strong interactions, and an additional fixation of the toxin at the channel binding site is carried out through the phospholipid environment. Our data suggest that Heteractis toxins could be used as molecular tools for NaV channel studies or insecticides rather than as pharmacological agents.

Biologically active polypeptides from the tropical sea anemone Radianthus macrodactylus.

Some biologically active polypeptides, three high and two low molecular weight cytolysins and four trypsin inhibitors were isolated from the sea anemone Radianthus macrodactylus and characterized. The purification steps involved acetone precipitation, gel filtration, ion-exchange, and affinity chromatography, and ion-exchange and reverse-phase HPLC. The relative molecular weight of high molecular weight Radianthus cytolysins named according to their N-terminal amino acids RTX-A (Ala), RTX-S (Ser) and RTX-G (Gly) was about 20,000. The isoelectric points were 9.8 for RTX-A and RTX-S, and 10.5 for RTX-G. The hemolytic activities of RTX-A, RTX-S and RTX-G were 3.5 x 10(4), 5.0 x10(4), and 1.0 x10(4)HU/mg, respectively, and were inhibited by sphingomyelin. The N-terminal amino acid sequence of RTX-A was determined as ALAGAIIAGAGLGLKILIEVLGEG-VKVKI-. Molecular weight of low molecular weight Radianthus cytolysins RmI, RmII, and of one trypsin inhibitor InI were 5100, 6100 and 7100, respectively. Isoelectric points for RmI and RmII were 9.2 and 9.3. Their hemolytic activity worked out 25 and 20 HU/mg, and was not inhibited by sphingomyelin. Toxicity of RmI and RmII was assessed by their histaminolytic activity. Amino acid composition of RmI and RmII was similar to that of tealiatoxin, histaminolytic cytolysin from the sea anemone Tealia felina.

Isolation, properties and partial amino acid sequence of a new actinoporin from the sea anemone Radianthus macrodactylus.

A new cytolytic toxin, actinoporin RTX-S II, was isolated from the sea anemone Radianthus macrodactylus with a high degree of purity by a combination of gel filtration, ion-exchange and reverse-phase chromatography. RTX-S II has molecular mass of 19,280 Da and isoelectric point of 10.0. The hemolytic activity of RTX-S II is inhibited by sphingomyelin. RTX-S II had an LD(50) of 70 mg/kg, and is lacking in phospholipase activity. The amino acid composition of this protein contains a high amount of basic and non-polar amino acids and no cysteine. The N-terminal sequence of RTX-S II was determined. The partial amino acid sequence (141 aa) of RTX-S II was deduced based on the cDNA sequence obtained with two oligonucleotides encoding the N-terminal portion of RTX-S II and the internal conserved cytolysin peptide by PCR. A comparison of the RTX-S II cDNA sequence and the rtx-s II gene obtained with the same PCR primers indicates that they are 100% identical at the nucleotide level. It shows that no introns are present in the corresponding region of the rtx-s II gene. Multiple alignments of RTX-S II with known sequences of actinoporins show that RTX-S II is highly homologous to magnificalysin II from Heteractis magnifica. The predicted secondary structure of RTX-S II is predominantly anti-parallel beta-structure, which is in good agreement with experimental data obtained from other sea anemones-actinoporins.

A new multigene superfamily of Kunitz-type protease inhibitors from sea anemone Heteractis crispa.

Despite a considerable number of publications devoted to isolation and physicochemical properties of protease inhibitors from sea anemones, virtually nothing is known about the structure of the genes, and the nature of their isoforms diversity. Using the PCR-based cloning approach we discovered the Kunitz-type multigene superfamily composed of distinct gene families (GS-, RG-, GG-, and GN-gene families). It has been identified only three full-length GS-transcripts indicating a much greater variety of Kunitz homologs in Heteractis crispa. We have examined an exon-intron structure of GS-genes; an open reading frame is interrupted by a single intron located at the middle of the signal peptide. 33 deduced mature GS-polypeptides have been categorized into three groups according to the nature of a P1 residue. Some of them corresponded to native Kunitz-type protease inhibitors earlier isolated from H. crispa. The deduced GS-polypeptide sequences demonstrated diverse charge distribution ranging from the local point charges forms to the overall positive ones. We have suggested that the GS-gene family has evolved through gene tandem duplication followed by adaptive divergence of the P1 residue in the reactive site selected for divergent functions in paralogs. The expansion of this Kunitz-type multigene superfamily during evolution is lineage-specific, providing the tropical sea anemone H. crispa with the ability to interact an increasing diversity of the preys and predators. Our results show that the Kunitz-type polypeptides are encoded by a multigene superfamily and realized via a combinatory Kunitz-type library in the H. crispa tentacles venom.

Analgesic compound from sea anemone Heteractis crispa is the first polypeptide inhibitor of vanilloid receptor 1 (TRPV1).

Venomous animals from distinct phyla such as spiders, scorpions, snakes, cone snails, or sea anemones produce small toxic proteins interacting with a variety of cell targets. Their bites often cause pain. One of the ways of pain generation is the activation of TRPV1 channels. Screening of 30 different venoms from spiders and sea anemones for modulation of TRPV1 activity revealed inhibitors in tropical sea anemone Heteractis crispa venom. Several separation steps resulted in isolation of an inhibiting compound. This is a 56-residue-long polypeptide named APHC1 that has a Bos taurus trypsin inhibitor (BPTI)/Kunitz-type fold, mostly represented by serine protease inhibitors and ion channel blockers. APHC1 acted as a partial antagonist of capsaicin-induced currents (32 +/- 9% inhibition) with half-maximal effective concentration (EC(50)) 54 +/- 4 nm. In vivo, a 0.1 mg/kg dose of APHC1 significantly prolonged tail-flick latency and reduced capsaicin-induced acute pain. Therefore, our results can make an important contribution to the research into molecular mechanisms of TRPV1 modulation and help to solve the problem of overactivity of this receptor during a number of pathological processes in the organism.