A CD25×TIGIT bispecific antibody induces anti-tumor activity through selective intratumoral Treg cell depletion.

Intratumoral regulatory T cells (Tregs) express high levels of CD25 and TIGIT, which are also recognized as markers of effector T cell (Teff) activation. Targeting these molecules each alone with monoclonal antibodies (mAbs) poses a risk of concurrently depleting both Teffs and peripheral Tregs, thereby compromising the effectiveness and selectivity of intratumoral Treg depletion. Here, leveraging the increased abundance of CD25+ TIGIT+ double-positive Tregs in the solid tumor microenvironment (but not in peripheral tissues), we explore the feasibility of using a CD25×TIGIT bispecific antibody (bsAb) to selectively deplete intratumoral Tregs. We initially constructed a bsAb co-targeting mouse CD25 and TIGIT, NSWm7210, and found that NSWm7210 conferred enhanced intratumoral Treg depletion, Teff activation, and tumor suppression as compared to the parental monotherapies in mouse models. We subsequently constructed a bsAb co-targeting human CD25 and TIGIT (NSWh7216), which preferentially eliminated CD25+ TIGIT+ double-positive cells over single-positive cells in vitro. NSWh7216 exhibited enhanced anti-tumor activity without toxicity of peripheral Tregs in CD25 humanized mice compared to the parental monotherapies. Our study illustrates the use of CD25×TIGIT bsAbs as effective agents against solid tumors based on selective depletion of intratumoral Tregs.

D-mannose facilitates immunotherapy and radiotherapy of triple-negative breast cancer via degradation of PD-L1.

Breast cancer is the most frequent malignancy in women worldwide, and triple-negative breast cancer (TNBC) patients have the worst prognosis and highest risk of recurrence. The therapeutic strategies for TNBC are limited. It is urgent to develop new methods to enhance the efficacy of TNBC treatment. Previous studies demonstrated that D-mannose, a hexose, can enhance chemotherapy in cancer and suppress the immunopathology of autoimmune diseases. Here, we show that D-mannose can significantly facilitate TNBC treatment via degradation of PD-L1. Specifically, D-mannose can activate AMP-activated protein kinase (AMPK) to phosphorylate PD-L1 at S195, which leads to abnormal glycosylation and proteasomal degradation of PD-L1. D-mannose-mediated PD-L1 degradation promotes T cell activation and T cell killing of tumor cells. The combination of D-mannose and PD-1 blockade therapy dramatically inhibits TNBC growth and extends the lifespan of tumor-bearing mice. Moreover, D-mannose-induced PD-L1 degradation also results in messenger RNA destabilization of DNA damage repair-related genes, thereby sensitizing breast cancer cells to ionizing radiation (IR) treatment and facilitating radiotherapy of TNBC in mice. Of note, the effective level of D-mannose can be easily achieved by oral administration in mice. Our study unveils a mechanism by which D-mannose targets PD-L1 for degradation and provides methods to facilitate immunotherapy and radiotherapy in TNBC. This function of D-mannose may be useful for clinical treatment of TNBC.

Scleral remodeling during myopia development in mice eyes: a potential role of thrombospondin-1.

BACKGROUND: Scleral extracellular matrix (ECM) remodeling plays a crucial role in the development of myopia, particularly in ocular axial elongation. Thrombospondin-1 (THBS1), also known as TSP-1, is a significant cellular protein involved in matrix remodeling in various tissues. However, the specific role of THBS1 in myopia development remains unclear. METHOD: We employed the HumanNet database to predict genes related to myopic sclera remodeling, followed by screening and visualization of the predicted genes using bioinformatics tools. To investigate the potential target gene Thbs1, we utilized lens-induced myopia models in male C57BL/6J mice and performed Western blot analysis to detect the expression level of scleral THBS1 during myopia development. Additionally, we evaluated the effects of scleral THBS1 knockdown on myopia development through AAV sub-Tenon's injection. The refractive status and axial length were measured using a refractometer and SD-OCT system. RESULTS: During lens-induced myopia, THBS1 protein expression in the sclera was downregulated, particularly in the early stages of myopia induction. Moreover, the mice in the THBS1 knockdown group exhibited alterations in myopia development in both refraction and axial length changed compared to the control group. Western blotting analysis confirmed the effectiveness of AAV-mediated knockdown, demonstrating a decrease in COLA1 expression and an increase in MMP9 levels in the sclera. CONCLUSION: Our findings indicate that sclera THBS1 levels decreased during myopia development and subsequent THBS1 knockdown showed a decrease in scleral COLA1 expression. Taken together, these results suggest that THBS1 plays a role in maintaining the homeostasis of scleral extracellular matrix, and the reduction of THBS1 may promote the remodeling process and then affect ocular axial elongation during myopia progression.

Integrated Analysis of Per- and Polyfluoroalkyl Substance Exposure and Metabolic Profiling of Elderly Residents Living near Industrial Plants.

Per- and polyfluoroalkyl substances (PFASs) are widely used in industrial production, causing potential health risks to the residents living around chemical industrial plants; however, the lack of data on population exposure and adverse effects impedes our understanding and ability to prevent risks. In this study, we performed screening and association analysis on exogenous PFAS pollutants and endogenous small-molecule metabolites in the serum of elderly residents living near industrial plants. Exposure levels of 11 legacy and novel PFASs were determined. PFOA and PFOS were major contributors, and PFNA, PFHxS, and 6:2 Cl-PFESA also showed high detection frequencies. Association analysis among PFASs and 287 metabolites identified via non-target screening was performed with adjustments of covariates and false discovery rate. Strongly associated metabolites were predominantly lipid and lipid-like molecules. Steroid hormone biosynthesis, primary bile acid biosynthesis, and fatty-acid-related pathways, including biosynthesis of unsaturated fatty acids, linoleic acid metabolism, α-linolenic acid metabolism, and fatty acid biosynthesis, were enriched as the metabolic pathways associated with mixed exposure to multiple PFASs, providing metabolic explanation and evidence for the potential mediating role of adverse health effects as a result of PFAS exposure. Our study achieved a comprehensive screening of PFAS exposure and associated metabolic profiling, demonstrating the promising application for integrated analysis of exposome and metabolome.

Organization of A2-Type Active Composite Nanorods.

Nanorods as building blocks are promising to construct functional superstructures. A paramagnetic Fe3O4-based composite nanorod is large-scale synthesized from the poly(2-vinylpyridine) (P2VP) side chain grafted polymer bottlebrush by electrostatics-mediated intramolecular crosslinking via metallic coordination. Ultrasonication-assisted fracturing of the composite nanorod derives the corresponding A2-type composite nanorods whose two ends are active with the metallic coordinated P2VP exposed. The active ends are prone to connection upon feeding ligands (acidic or alkaline) or metallic ions to trigger the organization of the A2-type nanorods toward functional superstructures. Their microstructure is tunable from linear nanowires to branches, which is dependent on the valent state of the assistant chemicals. The report method is easily extended to derive a family of A2-type active nanorods with varied compositions and functions which are capable to organize functional nanomaterials with tunable microstructure.

Contralateral effect in progression and recovery of lens-induced myopia in mice.

PURPOSE: Apart from genetic factors, recent animal studies on myopia have focused on localised mechanisms. In this study, we aimed to examine the contralateral effects of monocular experimental myopia and recovery, which cannot be explained by a mere local mechanism. METHODS: One eye of 3-week-old C57BL/6 male mice was fitted with a -30 dioptre (D) lens. The mice were distributed into two groups based on different conditions in the contralateral eye: either no lens (NLC) (n = 10) or a Plano lens on the contralateral eye (PLC) group (n = 6). Mice receiving no treatment on either eye were set as a control group (n = 6). Lenses were removed after 3 weeks of myopia induction. All mice were allowed to recover for 1 week in the same environment. Refractive status, axial length (AL) and choroidal thickness were measured before myopia induction, after 1 and 3 weeks of lens wear and after 1 week of recovery. RESULTS: One week after removing the lenses, complete recovery was observed in the eyes that wore the -30 D lenses. In both the PLC and NLC groups, the refractive status showed a myopic shift after lens removal. Additionally, the choroid was significantly thinned in these eyes. The -30 D wearing eye showed a significant increase in AL after 3 weeks of lens wear. While the AL of the -30 D wearing eye ceased to grow after the lens was removed, the AL in the PLC and NLC contralateral eyes increased, and the binocular ALs gradually converged. CONCLUSIONS: Recovery of lens-induced myopia was observed in mouse models. In the fellow eyes, the effects, including thinning of the choroid and changes in refractive status, were triggered by contralateral visual cues.

Anticoagulant Property of a Sulfated Polysaccharide with Unique Structural Characteristics from the Green Alga Chaetomorpha aerea.

Sulfated polysaccharides from marine algae have attracted a great amount of attentions for the development of marine drugs due to their unique structural features, and they are great potential sources of naturally occurring anticoagulant agents. The genus Chaetomorpha is one of the largest genera in green algae and has a worldwide distribution. In the present study, a homogeneous polysaccharide from Chaetomorpha aerea, designated as PCA, was obtained by alkali extraction, anion-exchange and size-exclusion chromatography. Based on the results of chemical and spectroscopic analyses, PCA was a sulfated galactoarabinan which was mainly constituted of a backbone of →4)-ß-l-Arap-(1→ unit, partially sulfated at C-3 of →4)-ß-l-Arap-(1→ and C-4 of →6)-α-d-Galp-(1→. The side chains consisting of →6)-α-d-Galp-(1→ and →5)-α-l-Araf-(1→ residues were in C-2 of →4)-ß-l-Arap-(1→ unit. PCA had a strong anticoagulant activity in vitro as evaluated by the assays of activated partial thromboplastin time, thrombin time and fibrinogen level. The obvious anticoagulant activity in vivo of PCA was also found. PCA significantly inhibited the activities of the intrinsic coagulation factors XII, XI, IX and VIII, and exhibited weak inhibition effects on the common coagulation factors II and X. The anticoagulant mechanism of PCA was attributed to strong thrombin inhibition potentiated by heparin cofactor II or antithrombin III, and it also possessed an apparent inhibition effect on coagulation factor Xa mediated by antithrombin III. The investigation demonstrated that PCA could be a promising anticoagulant agent for health promotion and the treatment of thrombotic diseases.

Application and Molecular Mechanisms of Extracellular Vesicles Derived from Mesenchymal Stem Cells in Osteoporosis.

Osteoporosis (OP) is a chronic bone disease characterized by decreased bone mass, destroyed bone microstructure, and increased bone fragility. Accumulative evidence shows that extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) (MSC-EVs), especially exosomes (Exos), exhibit great potential in the treatment of OP. However, the research on MSC-EVs in the treatment of OP is still in the initial stage. The potential mechanism has not been fully clarified. Therefore, by reviewing the relevant literature of MSC-EVs and OP in recent years, we summarized the latest application of bone targeted MSC-EVs in the treatment of OP and further elaborated the potential mechanism of MSC-EVs in regulating bone formation, bone resorption, bone angiogenesis, and immune regulation through internal bioactive molecules to alleviate OP, providing a theoretical basis for the related research of MSC-EVs in the treatment of OP.

A Cross-Species Reactive TIGIT-Blocking Antibody Fc Dependently Confers Potent Antitumor Effects.

The T cell immunoreceptor with Ig and ITIM domains (TIGIT) has been shown to exert inhibitory roles in antitumor immune responses. In this study, we report the development of a human mAb, T4, which recognizes both human and mouse TIGIT and blocks the interaction of TIGIT with its ligand CD155 in both species. The T4 Ab targets the segment connecting F and G strands of TIGIT's extracellular IgV domain, and we show in studies with mouse tumor models that the T4 Ab exerts strong antitumor activity and induces durable immune memory against various tumor types. Mechanistically, we demonstrate that the T4 Ab's antitumor effects are mediated via multiple immunological impacts, including a CD8+ T immune response and Fc-mediated effector functions, through NK cells that cause significant reduction in the frequency of intratumoral T regulatory cells (Tregs). Notably, this Treg reduction apparently activates additional antitumor CD8+ T cell responses, targeting tumor-shared Ags that are normally cryptic or suppressed by Tregs, thus conferring cross-tumor immune memory. Subsequent engineering for Fc variants of the T4 Ab with enhanced Fc-mediated effector functions yielded yet further improvements in antitumor efficacy. Thus, beyond demonstrating the T4 Ab as a promising candidate for the development of cancer immunotherapies, our study illustrates how the therapeutic efficacy of an anti-TIGIT Ab can be improved by enhancing Fc-mediated immune effector functions. Our insights about the multiple mechanisms of action of the T4 Ab and its Fc variants should help in developing new strategies that can realize the full clinical potential of anti-TIGIT Ab therapies.

Immunomodulatory Activity In Vitro and In Vivo of a Sulfated Polysaccharide with Novel Structure from the Green Alga Ulvaconglobata Kjellman.

Algae accumulate large amounts of polysaccharides in their cell walls or intercellular regions. Polysaccharides from algae possess high potential as promising candidates for marine drug development. In this study, a sulfated polysaccharide, UCP, from the green alga Ulva conglobata Kjellman was obtained by water extraction, anion-exchange, and size-exclusion chromatography purification, and its structure was characterized by a combination of chemical and spectroscopic methods. UCP mainly consisted of →4)-α/ß-l-Rhap-(1→, →4)-ß-d-Xylp-(1→ and →4)-ß-d-GlcAp-(1→ residues. Sulfate ester groups were substituted mainly at C-3 of →4)-l-Rhap-(1→ and C-2 of →4)-ß-d-Xylp-(1→. Partial glycosylation was at C-2 of →4)-α-l-Rhap-(1→ residues. UCP possessed a potent immunomodulatory effect in vitro, evaluated by the assays of lymphocyte proliferation and macrophage phagocytosis. The immunomodulatory activity of UCP in vivo was further investigated using immunosuppressive mice induced by cyclophosphamide. The results showed that UCP markedly increased the spleen and thymus indexes and ameliorated the cyclophosphamide-induced damage to the spleen and thymus. UCP could increase the levels of white blood cells, lymphocytes, and platelets, and improve the hematopoietic inhibition caused by cyclophosphamide. Moreover, UCP significantly promoted the secretions of the immunoglobulin (Ig)G, IgE, and IgM. The data demonstrated that UCP is a novel sulfated polysaccharide and may be a promising immunomodulatory agent.

Fluorescence spectral shape analysis for nucleotide identification.

We report a conjugated polyelectrolyte fluorescence-based biosensor P-C-3 and a general methodology to evaluate spectral shape recognition to identify biomolecules using artificial intelligence. By using well-defined analytes, we demonstrate that the fluorescence spectral shape of P-C-3 is sensitive to minor structural changes and exhibits distinct signature patterns for different analytes. A method was also developed to select useful features to reduce computational complexity and prevent overfitting of the data. It was found that the normalized intensity of 3 to 5 selected wavelengths was sufficient for the fluorescence biosensor to classify 13 distinct nucleotides and distinguish as little as single base substitutions at distinct positions in the primary sequence of oligonucleotides rapidly with nearly 100% classification accuracy. Photophysical studies led to a model to explain the mechanism of these fluorescence spectral shape changes, which provides theoretical support for applying this method in complicated biological systems. Using the feature selection algorithm to measure the relative intensity of a few selected wavelengths significantly reduces measurement time, demonstrating the potential for fluorescence spectrum shape analysis in high-throughput and high-content screening.

Structural Characterization, Antioxidant and Antitumor Activities of the Two Novel Exopolysaccharides Produced by Debaryomyces hansenii DH-1.

Exopolysaccharides produced by edible microorganisms exhibit excellent constructive physicochemical and significant biological activity, which provide advantages for the food or pharmaceutical industries. Two novel exopolysaccharides produced by Debaryomyces hansenii DH-1 were characterized, named S1 and S2, respectively. S1, with a molecular weight of 34.594 kDa, primarily consisted of mannose and glucose in a molar ratio of 12.19:1.00, which contained a backbone fragment of α-D-Manp-(1→4)-α-D-Manp-(1→2)-α-D-Glcp-(1→3)-α-D-Manp-(1→3)-ß-D-Glcp-(1→4)-ß-D-Manp-(1→. S2, with a molecular weight of 24.657 kDa, was mainly composed of mannose and galactose in a molar ratio of 4.00:1.00, which had a backbone fragment of α-D-Manp-(1→6)-ß-D-Manp-(1→2)-α-D-Manp-(1→4)-α-D-Galp-(1→3)-ß-D-Manp-(1→6)-α-D-Manp-(1→. Both S1 and S2 exhibited good thermal stability and potent hydroxyl radical scavenging activity, with ~98%. Moreover, S1 possessed an additional strong iron-reducing capacity. In vitro antitumor assays showed that S1 and S2 significantly inhibited the proliferation of Hela, HepG2, and PC-9 cancer cells. Moreover, PC-9 was more sensitive to S1 compared with S2. The above results indicate that S1 and S2 have great potential to be utilized as natural antioxidants and candidates for cancer treatment in the food and pharmaceutical industries.

Photoinduced Intramolecular Electron Transfer in Phenylene Ethynylene Naphthalimide Oligomers.

This paper reports a photophysical investigation of a series of phenylene ethynylene oligomers (OPE) that are end-substituted with a 1,8-naphthalene imide (NI) acceptor. The NI acceptor is attached to the terminus of the OPEs via an ethynylene (-C≡C-) unit that is linked at the 4-position of the NI unit. A series of three oligomers is investigated, OPE1-NI, OPE3-NI, and OPE5-NI, which contain 1, 3, and 5 phenylene ethynylene repeat units, respectively. The properties of the OPEn-NI series are compared to a corresponding set of unsubstituted OPEs, OPE3 and OPE5, which contain 3 and 5 phenylene ethynylene repeats, respectively. The photophysics of all the compounds are interrogated using a variety of techniques including steady-state absorption, steady-state fluorescence, two-photon absorption, time-resolved fluorescence, and transient absorption spectroscopy on femtosecond-to-microsecond time scales. The effect of solvent polarity on the properties of the oligomers is examined. The results show that the NI-substituted oligomers feature a lowest charge transfer (CT) excited state, where the OPE segment acts as the donor and the NI moiety is the acceptor (OPEn•+-NI•-). The absorption spectra in one-photon and two-photon exhibit a clear manifold of absorption features that can be attributed to direct CT absorption. In moderately polar solvents, the emission is dominated by a broad, solvatochromic band that is due to radiative decay from the CT excited state. Ultrafast transient absorption provides evidence for initial population of a locally excited state (LE) which in moderately polar solvents rapidly (∼1 ps) evolves into the CT excited state. The structure, spectroscopy, and dynamics of the CT state are qualitatively similar for OPE3-NI and OPE5-NI, suggesting that delocalization in the OPE segment does not have much effect on the structure or energetics of the CT excited state.

Comparison between estimated and measured myopia progression in Hong Kong children without myopia control intervention.

PURPOSE: To compare myopia progression estimated by the Brien Holden Vision Institute (BHVI) Myopia Calculator with cycloplegic measures in Hong Kong children wearing single-vision distance spectacles over a 1- and 2-year period. METHODS: Baseline age, spherical equivalent refraction (SER) and ethnicity of control participants from previous longitudinal myopia studies were input into the BHVI Myopia Calculator to generate an estimate of the SER at 1 and 2 years. Differences between the measured and estimated SER (116 and 100 participants with 1- and 2-year subjective refraction data, respectively, and 111 and 95 participants with 1- and 2-year objective refraction, respectively) were analysed, and the measured SER compared with the 95% confidence interval (CI) of the estimated SER. RESULTS: In children aged 7-13 years, 36% progressed within the 95% CI of the Myopia Calculator's estimate, whereas 33% became less myopic than predicted (range 0.31 to 1.92 D less at 2 years) and 31% became more myopic than predicted (range 0.25 to 2.33 D more myopic at 2 years). The average difference between the estimated and measured subjective or objective SER at 1 and 2 years of follow-up was not clinically significant (<0.25 D). CONCLUSIONS: On average, the BHVI Myopia Calculator estimated SER was in close agreement with measured cycloplegic SER after 1 and 2 years of follow-up (mean differences < 0.25 D). However, the measured myopia progression only fell within the 95% CI of the estimated SER for 32%-38% of children, suggesting that the BHVI 'without management' progression data should be interpreted with caution. The inclusion of additional data, modified to include axial elongation, from longitudinal studies of longer duration with larger sample sizes and a range of racial backgrounds may improve the Calculator's ability to predict future myopia progression for individual children.

Chemical Structure and Anticoagulant Property of a Novel Sulfated Polysaccharide from the Green Alga Cladophora oligoclada.

Marine macroalgae are efficient producers of sulfated polysaccharides. The algal sulfated polysaccharides possess diverse bioactivities and peculiar chemical structures, and represent a great potential source to be explored. In the present study, a heparinoid-active sulfated polysaccharide was isolated from the green alga Cladophora oligoclada. Results of chemical and spectroscopic analyses indicated that the sulfated polysaccharide was composed of →6)-ß-d-Galp-(1→, ß-d-Galp-(1→, →6)-α-d-Glcp-(1→ and →3)-ß-d-Galp-(1→ units with sulfate esters at C-2/C-4 of →6)-ß-d-Galp-(1→, C-6 of →3)-ß-d-Galp-(1→ and C-3 of →6)-α-d-Glcp-(1→ units. The branches consisting of ß-d-Galp-(1→ and →6)-ß-d-Galp-(1→ units were located in C-3 of →6)-ß-d-Galp-(1→ units. The sulfated polysaccharide exhibited potent anticoagulant activity in vitro and in vivo as evaluated by activated partial thromboplastin time (APTT), thrombin time, and the fibrinogen level. For the APTT, the signal for clotting time was more than 200 s at 100 µg/mL in vitro and at 15 mg/kg in vivo. The obvious thrombolytic activity of the sulfated polysaccharide in vitro was also found. The mechanism analysis of anticoagulant action demonstrated that the sulfated polysaccharide significantly inhibited the activities of all intrinsic coagulation factors, which were less than 1.0% at 50 µg/mL, but selectively inhibited common coagulation factors. Furthermore, the sulfated polysaccharide strongly stimulated the inhibition of thrombin by potentiating antithrombin-III (AT-III) or heparin cofactor-II, and it also largely promoted the inhibition of factor Xa mediated by AT-III. These results revealed that the sulfated polysaccharide from C. oligoclada had potential to become an anticoagulant agent for prevention and therapy of thrombotic diseases.

An Application Exploiting Aurophilic Bonding and iClick to Produce White Light Emitting Materials.

The paper focuses on exploiting aurophilic bonding to produce white light emitting materials. Inorganic Click (iClick) is employed to link two or four Au(I) metal ions through a triazolate bridge. Depending on the choice of phosphine ligand (PEt3 or PPh3), dinuclear Au2-FO or tetranuclear Au4-FO complexes can be controllably synthesized (FO = 2-(9,9-dioctylfluoreneyl-)). The iClick products Au2-FO and Au4-FO are characterized by combustion analysis and multinuclear NMR, TOCSY 1D, 1H-13C gHMBC, and 1H-13C gHSQC. In addition, the photophysical properties of Au2-FO and Au4-FO were examined in THF solution. Transient absorption spectroscopy was employed to elucidate the excited state features of the gold compounds. Solution processed OLEDs were fabricated and characterized, which gave white light electroluminescence with CIE coordinates (0.34, 0.36), as seen referenced to CIE standard illuminant D65 (0.31, 0.32). TDDFT computational analysis of Au2-FO and Au4-FO reveals the origin of light emission. In the case of Au4-FO, direct excitation leads to increased aurophilic bonding in the excited state, and as a result the emission profile is broadened to cover a larger region of the visible spectrum, thus giving white light emission. Designing molecules that can access or increase aurophilic bonding in the excited state provides another tool for fine-tuning the emission profiles of gold complexes.

Anticoagulant and Antithrombotic Properties in Vitro and in Vivo of a Novel Sulfated Polysaccharide from Marine Green Alga Monostroma nitidum.

Sulfated polysaccharides from marine algae have high potential as promising candidates for marine drug development. In this study, a homogeneous sulfated polysaccharide from the marine green alga Monostroma nitidum, designated MS-1, was isolated using water extraction and anion-exchange and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that MS-1 mainly consisted of →3)-α-l-Rhap-(1→ and →2)-α-l-Rhap-(1→ residues, with additional branches consisting of 4-linked ß-d-xylose, 4-/6-linked d-glucose, terminal ß-d-glucuronic acid, and 3-/2-linked α-l-rhamnose. Sulfate ester groups substituted mainly at C-2/C-4 of →3)-α-l-Rhap-(1→ and C-4 of →2)-α-l-Rhap-(1→ residues, slightly at C-2 of terminal ß-d-glucuronic residues. MS-1 exhibited strong anticoagulant activity in vitro and in vivo as evaluated by the activated partial thromboplastin time and thrombin time assays, and significantly decreased platelet aggregation. The anticoagulant activity mechanism of MS-1 was mainly attributed to strong potentiation thrombin by heparin cofactor-II, and it also hastened thrombin and coagulation factor Xa inhibitions by potentiating antithrombin-III. MS-1 possessed markedly thrombolytic activity evaluated by plasminogen activator inhibitior-1, fibrin degradation products, and D-dimer levels using rats plasma, and recanalization rate by FeCl3-induced carotid artery thrombosis in mice. MS-1 exhibited strong antithrombotic activity in vitro and in vivo evaluated by the wet weighs and lengths of thrombus, and thrombus occlusion time by electrically-induced carotid artery thrombosis in rats. These results suggested that MS-1 could be a promising marine drug for prevention and therapy of thromboembolic disease.

Structural Characteristics and Anticoagulant Property In Vitro and In Vivo of a Seaweed Sulfated Rhamnan.

Great diversity and metabolite complexity of seaweeds offer a unique and exclusive source of renewable drug molecules. Polysaccharide from seaweed has potential as a promising candidate for marine drug development. In the present study, seaweed polysaccharide (SPm) was isolated from Monostroma angicava, the polymeric repeat units and anticoagulant property in vitro and in vivo of SPm were investigated. SPm was a sulfated polysaccharide which was mainly constituted by 3-linked, 2-linked-α-l-rhamnose residues with partially sulfate groups at C-2 of 3-linked α-l-rhamnose residues and C-3 of 2-linked α-l-rhamnose residues. Small amounts of xylose and glucuronic acid exist in the forms of ß-d-Xylp(4SO4)-(1→ and ß-d-GlcA-(1→. SPm effectively prolonged clotting time as evaluated by the activated partial thromboplastin time and thrombin time assays, and exhibited strong anticoagulant activity in vitro and in vivo. The fibrin(ogen)olytic and thrombolytic properties of SPm were evaluated by plasminogen activator inhibitior-1, fibrin degradation products, D-dimer and clot lytic rate assays using rats plasma, and the results showed that SPm possessed high fibrin(ogen)olytic and thrombolytic properties. These results suggested that SPm has potential as a novel anticoagulant agent.