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Chemical Structure of the Core Region of Lipopolysaccharides
Published in Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison, Endotoxin in Health and Disease, 2020
For the structure and function of Chlamydia LPS, the reader is referred to Chapter 13 of this book, which includes all aspects of chlamydia core regions. Briefly, we established the structures of the core regions of C. trachomatis and C. psittaci by analysis of LPS of recombinant deep-rough E. coli bacteria, which express the respective chlamydia Kdo transferase (Table 10) (17,18,228–234). Chlamydial Kdo transferases are multifunctional enzymes that transfer three Kdo residues in C. trachomatis and C. pneumoniae (235) and at least four in C. psittaci. In the last case, the characterized branched tetrasaccharide represents the first oligosaccharide consisting of a cluster of four Kdo residues (see Acinetobacter, Table 8).
Heparin and Related Molecules: Antiproliferative and Anti-Inflammatory Effects in the Airways
Published in Alastair G. Stewart, AIRWAY WALL REMODELLING in ASTHMA, 2020
Stephen A. Kilfeather, Clive Page
The antiproliferative activity of heparin against vascular smooth muscle is dependent upon both charge and chain length of the molecule without requiring the antithrombin III–binding site.25,35 Hyaluronic acid, dermatan sulphate, protamine sulphate, and chondroitin sulphate do not inhibit VSMC division,103,104 indicating that chain length, charge, and sulphation together are insufficient and specific distribution of charged groups is required for expression of antiproliferative activity. Tetrasaccharides generated from nitrous acid treatment of heparin are not antiproliferative,35 but antiproliferative tetrasaccharides lacking the pentasaccharide antithrombin III-binding site can be released from endothelial cells.105 This demonstrates the importance of uptake and subsequent secretion of modified GAGs and shows that observed antiproliferative effects of smooth muscle tissue-conditioned media102 could be endothelial derived. The expansion of vascular and endothelial networks in asthmatic airways and potential reciprocal regulation between airway smooth muscle and endothelial cells warrant exploration.
Mass Spectrometric Analysis
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
A total of eight minor factors of the nebramycin complex have been identified with the aid of El and FD mass spectrometry [149]. The FD spectra exhibited molecular ions; the El spectra displayed fragment ions useful for determining the carbohydrate components, including some derived by reverse Diels-Alder rearrangements. Protonated molecular ions were also observed in some of the El spectra. The complex includes di-, tri-, and tetrasaccharides.
Hyaluronic acid-based nanoparticles to deliver drugs to the ocular posterior segment
Published in Drug Delivery, 2023
Both in vitro and in vivo studies have shown that the MW of HA determines its biological activity via its different effects on cellular signaling and function. Monslow et al. (2015) divided HA into high MW (with a MW higher than 1000 kDa), medium MW (250–1000 kDa), low MW (10–250 kDa), and oligo-HA (with a MW lower than 10 kDa) to investigate the biological activity in different tissues. In vivo, high-MW HA plays a positive role, such as inhibiting vascular injury with pathological significance, inhibiting cell migration and tumor growth in cancer, and enhancing immunosuppression in inflammation. Medium- and low-MW HA can act on vascular endothelial cells to inhibit angiogenesis. They can indirectly cause lung epithelial cells, chondrocytes, liver endothelial cells, and vascular smooth muscle cells to produce more inflammatory substances. Oligo-HA can enhance vascular tube formation, endothelial cell proliferation, and cytokine release. Stren and coworkers came to the same conclusion that small HA polymer fragments are angiogenic, inflammatory, and immunostimulatory (Stern et al., 2006). Inflammation is mainly induced by tetrasaccharide HA, whereas disaccharide HA may be able to inhibit it through Toll-like receptor 4 (Han et al., 2022). A wide range of different and often contradictory impacts on a variety of biological activities have been demonstrated in the literature, but this has not been explored in ophthalmology.
Novel approaches to glycomimetic design: development of small molecular weight lectin antagonists
Published in Expert Opinion on Drug Discovery, 2021
Vishnu C. Damalanka, Amarendar Reddy Maddirala, James W. Janetka
Using a fragment-based approach guided by NMR, Ernst and coworkers discovered a tetrasaccharide sLex based compound 47 (IC50 = 1 mM) (Figure 9). Subsequently, through multiple studies, they increased affinity by an amazing >30,000 fold and have identified optimized compounds like 48 (Figure 9) with low nanomolar affinity (KD = 30 nM) [174–178]. Subsequent studies were conducted at the company Glycomimetics focused on targeting the sulfate-binding domain in the L- and P-selectins. This work led to the discovery of the pan-selectin antagonist GMI-1070 (Rivipansel, 49) which was evaluated in clinical trials for treating vaso-occlusive anemia in hospitalized patients with sickle cell disease [179–181] but was unsuccessful in Phase III due to lack of efficacy.
Mucoadhesive films based on gellan gum/pectin blends as potential platform for buccal drug delivery
Published in Pharmaceutical Development and Technology, 2020
Fabíola Garavello Prezotti, Izabel Siedle, Fernanda Isadora Boni, Marlus Chorilli, Ingrid Müller, Beatriz Stringhetti Ferreira Cury
P has a linear structure, mainly constituted of α-(1–4)-D-galacturonic acid residues that can be partially methyl and acetyl esterified, occasionally interrupted by α-(1–2)-L-rhamnose residues, and neutral sugars such as L-rhamnose, L-arabinose, L-fucose, D-galactose and D-xylose are present in side chains (Yapo 2011; Carbinatto et al. 2012). Its pKa is between 3 and 4 (Sriamornsak et al. 2010). GG structure is composed by repeating units of the tetrasaccharide (β-1,3-D-glucose, β-1,4-D-glucuronic acid, β-1,4-D-glucose and α-1,4-L-rhamnose) (Chandrasekaran et al. 1988; Giavasis et al. 2000), with pKa near 3.5 due to presence of glucuronic acid residues (Picone and Cunha 2013). Both of these polysaccharide present well-known mucoadhesive properties (Narkar et al. 2010; Prezotti et al. 2014).