Heparanase and Syndecan-4 Are Involved in Low Molecular Weight Fucoidan-Induced Angiogenesis

Multi-Pharmaceutical Activities of Chinese Herbal Polysaccharides in the Treatment of Pulmonary Fibrosis: Concept and Future Prospects

Pulmonary fibrosis is a fatal chronic progressive respiratory disease, characterized by continuous scarring of the lung parenchyma, leading to respiratory failure and death. The incidence of PF has increased over time. There are drugs, yet, there are some limitations. Hence, it is of importance to find new therapies and new drugs to replace the treatment of pulmonary fibrosis. In recent years, there have been a great number of research reports on the treatment of traditional Chinese medicine polysaccharides in various system fields. Among them, the treatment of PF has also gained extensive attention. This review summarized the source of polysaccharides, the drug activity of traditional Chinese medicine, and the protective effects on targets of Pulmonary fibrosis. We hope it can inspire researchers to design and develop polysaccharides, serving as a reference for potential clinical therapeutic drugs.

Distribution of heparan sulfate correlated with the expression of heparanase-1 and matrix metalloproteinase-9 in an ovariectomized rats skin

There are few studies on heparan sulfate (HS) in the skin, during aging, when estrogen is suppressed. The enzyme heparanase-1 (HPSE-1), has its 17β-estrogen-regulated expression in pathological conditions such as cancer and chronic inflammatory diseases. HPSE-1 is correlated with the matrix metalloproteinase-9 (MMP-9), an endopeptidase that also undergoes estrogen action. We investigated the distribution of HS, expression HPSE-1 and MMP-9 in the skin of adult rats at different ages and in the age-matched ovariectomized rats to evaluate the influence of low estrogen on the distribution of HS. Thirty female Wistar rats were used. Rats underwent to a sham surgery (ctr, n = 15) or to a bilateral ovariectomy (ovx, n = 15) and were euthanized after 45, 75, and 90 days after ovariectomy. Morphological, morphometric, biochemical, and reverse transcriptase polymerase chain reaction (RT-PCR) methodologies were used. A significant decrease (P < 0.001) in total skin thickness was observed in the ctr and ovx animals, being higher in the older animals. The thickness of the epidermis and dermis decreased; however, the proportion in the total skin remained similar comparing ctr and ovx. An increase of HS with increasing age and ovariectomy was observed. The expression of the HPSE-1 and MMP-9 enzymes decreased, being higher in old animals. A correlation between the increase of HS and the decrease of the HPSE-1 was demonstrated in both groups. Overall, these data suggested that estrogen acts in the regulation of the expression of the HPSE-1, not only in pathological states, as already established, but also in aging.

A low-molecular-weight galactofucan from the seaweed, Spatoglossum schröederi, binds fibronectin and inhibits capillary-like tube formation in vitro

A low-molecular-weight (LMW) heterofucan (designated fucan B) was obtained from the brown seaweed, Spatoglossum schröederi, and its activity as an inhibitor of capillary-like tube formation by endothelial cells (ECs) was analyzed. Chemical, infrared and electrophoretic analyses confirmed the identity of fucan B. In contrast to other LMW fucans, fucan B (0.012-0.1 mg/mL) inhibited ECs capillary-like tube formation in a concentration-dependent manner. In addition, fucan B (0.01-0.05 mg/mL) did not affect ECs proliferation. Fucan B also inhibited ECs migration on a fibronectin-coated surface, but not on laminin- or collagen-coated surfaces. Biotinylated fucan B was used as a probe to identify its localization. Confocal microscopy experiments revealed that biotinylated fucan did not bind to the cell surface, but rather only to fibronectin. Our findings suggest that fucan B inhibits ECs capillary-like tube formation and migration by binding directly to fibronectin and blocking fibronectin sites recognized by cell surface ligands. However, further studies are needed to evaluate the in vivo effects of fucan B.

The Role of Endothelial Surface Glycocalyx in Mechanosensing and Transduction

The endothelial cells (ECs) forming the inner wall of every blood vessel are constantly exposed to the mechanical forces generated by blood flow. The EC responses to these hemodynamic forces play a critical role in the homeostasis of the circulatory system. A variety of mechanosensors and transducers, locating on the EC surface, intra- and trans-EC membrane, and within the EC cytoskeleton, have thus been identified to ensure proper functions of ECs. Among them, the most recent candidate is the endothelial surface glycocalyx (ESG), which is a matrix-like thin layer covering the luminal surface of the EC. It consists of various proteoglycans, glycosaminoglycans, and plasma proteins and is close to other prominent EC mechanosensors and transducers. This chapter summarizes the ESG composition, thickness, and structure observed by different labeling and visualization techniques and in different types of vessels. It also presents the literature in determining the ESG mechanical properties by atomic force microscopy and optical tweezers. The molecular mechanisms by which the ESG plays the role in EC mechanosensing and transduction are described as well as the ESG remodeling by shear stress, the actin cytoskeleton, the membrane rafts, the angiogenic factors, and the sphingosine-1-phosphate.

Identification of a Pro-Angiogenic Potential and Cellular Uptake Mechanism of a LMW Highly Sulfated Fraction of Fucoidan from Ascophyllum nodosum

Herein we investigate the structure/function relationships of fucoidans from Ascophyllum nodosum to analyze their pro-angiogenic effect and cellular uptake in native and glycosaminoglycan-free (GAG-free) human endothelial cells (HUVECs). Fucoidans are marine sulfated polysaccharides, which act as glycosaminoglycans mimetics. We hypothesized that the size and sulfation rate of fucoidans influence their ability to induce pro-angiogenic processes independently of GAGs. We collected two fractions of fucoidans, Low and Medium Molecular Weight Fucoidan (LMWF and MMWF, respectively) by size exclusion chromatography and characterized their composition (sulfate, fucose and uronic acid) by colorimetric measurement and Raman and FT-IR spectroscopy. The high affinities of fractionated fucoidans to heparin binding proteins were confirmed by Surface Plasmon Resonance. We evidenced that LMWF has a higher pro-angiogenic (2D-angiogenesis on Matrigel) and pro-migratory (Boyden chamber) potential on HUVECs, compared to MMWF. Interestingly, in a GAG-free HUVECs model, LMWF kept a pro-angiogenic potential. Finally, to evaluate the association of LMWF-induced biological effects and its cellular uptake, we analyzed by confocal microscopy the GAGs involvement in the internalization of a fluorescent LMWF. The fluorescent LMWF was mainly internalized through HUVEC clathrin-dependent endocytosis in which GAGs were partially involved. In conclusion, a better characterization of the relationships between the fucoidan structure and its pro-angiogenic potential in GAG-free endothelial cells was required to identify an adapted fucoidan to enhance vascular repair in ischemia.

Fucoidans in Nanomedicine

Fucoidans are widespread cost-effective sulfated marine polysaccharides which have raised interest in the scientific community over last decades for their wide spectrum of bioactivities. Unsurprisingly, nanomedicine has grasped these compounds to develop innovative therapeutic and diagnostic nanosystems. The applications of fucoidans in nanomedicine as imaging agents, drug carriers or for their intrinsic properties are reviewed here after a short presentation of the main structural data and biological properties of fucoidans. The origin and the physicochemical specifications of fucoidans are summarized in order to discuss the strategy of fucoidan-containing nanosystems in Human health. Currently, there is a need for reproducible, well characterized fucoidan fractions to ensure significant progress.

Syndecan-4 shedding impairs macrovascular angiogenesis in diabetes mellitus

PURPOSE

Syndecan-4 (synd4) is a ubiquitous heparan sulfate proteoglycan cell surface receptor that modulates cell proliferation, migration, mechanotransduction, and endocytosis. The extracellular domain of synd4 sheds heavily in acute inflammation, but the shedding of synd4 in chronic inflammation, such as diabetes mellitus (DM), is still undefined. We investigated the alterations of synd4 endothelial expression in DM and the influence of impaired synd4 signaling on angiogenesis in human umbilical vein endothelial cells (HUVECs), diabetic rats, synd4 null mice, and db/db mice.

MATERIAL AND METHODS

HUVECs were incubated with advanced glycation end products (AGEs). Western blot analysis was used to determine synd4 protein expression and ELISA was used to detect soluble synd4 fragments. The concentration of synd4 in the aortic endothelia of diabetic rats was detected by immunohistochemical staining. Aortic ring assays were performed to study the process of angiogenesis in the diabetic rats and in synd4 null and db/db mice. Recombinant adenoviruses containing the synd4 gene or null were constructed to enhance synd4 aortic expression in db/db mice.

RESULTS

Western blot analysis showed decreased expression of the synd4 extracellular domain in HUVECs, and ELISA detected increased soluble fragments of synd4 in the media. Synd4 endothelial expression in the aortas of diabetic rats was decreased. Aortic ring assay indicated impaired angiogenesis in synd4 null and db/db mice, which was partially reversed by synd4 overexpression in db/db mice.

CONCLUSION

Synd4 shedding from vascular endothelial cells played an important role in the diabetes-related impairment of angiogenesis.