An anticomplement homogeneous polysaccharide from Hedyotis diffusa attenuates lipopolysaccharide-induced acute lung injury and inhibits neutrophil extracellular trap formation.

BACKGROUND: Owing to the involvement of the overactivated complement system in acute lung injury (ALI) development, anticomplement components may attenuate ALI. Hedyotis diffusa is a traditional Chinese medicine for treating lung heat and its crude polysaccharides (HDP) exhibit significant anticomplement activity in vitro. PURPOSE: To obtain an anticomplement homogeneous polysaccharide from HDP and verify its therapeutic effect and mechanism on ALI. METHODS: Diethylaminoethyl-52 (DEAE-52) cellulose and gel permeation columns were used to isolate a homogeneous polysaccharide HD-PS-3, which was then characterized using nuclear magnetic resonance (NMR) and methylation analysis. In vitro, the anticomplement activities of HD-PS-3 through classical and alternative pathways were determined using a hemolytic test. The therapeutic effects of HDP and HD-PS-3 on ALI were evaluated in lipopolysaccharide (LPS) intratracheal instilled mice. Hematoxylin and eosin (H&E) staining, enzyme-linked immunosorbent assay (ELISA), and immunohistochemical staining were used to assess histological changes, measure cytokine levels, and evaluate the degree of complement component 3c (C3c) deposition and neutrophil infiltration, respectively. ELISA, western blotting, and immunofluorescence were used to analyze neutrophil extracellular trap (NET) formation. RESULTS: From HDP, 1.5 g of the homogeneous polysaccharide HD-PS-3 was obtained. HD-PS-3 was an acidic heteropolysaccharide with an acetyl group, which was composed of →4,6)-α-Glcp-(1→, →3,4)-α-Glcp-(1→, →4)-α-Glcp-(1→, →4,6)-α-Galp-(1→, →5)-α-Araf-(1→, α-Rhap-(1→, α-Araf-(1→, α-GlcpA-(1→, →4)-ß-Manp-(1→, ß-Manp-(1→ and →3)-ß-Manp-(1→. The in vitro results suggest that HD-PS-3 exhibited anticomplement activity with CH50 and AP50 values of 115 ± 12 µg/ml and 307 ± 11 µg/ml, respectively. After confirming the efficacy of HDP (200 mg/kg) in attenuating lung injury, the effect of HD-PS-3 on ALI was also investigated. HD-PS-3 (75 and 150 mg/kg) attenuated LPS-induced ALI as well, evidenced by lung pathology, lung injury scores, protein concentration, leukocyte counts, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) contents in bronchoalveolar lavage fluid (BALF). Mechanistically, HD-PS-3 inhibited complement activation, manifested in reduced pulmonary C3c deposition in lung tissue and complement component 3a (C3a) content in BALF. Neutrophil recruitment was also reduced by HD-PS-3, with significantly reduced pulmonary neutrophil infiltration and lower levels of C-X-C motif chemokine ligand 1 (CXCL1) and myeloperoxidase (MPO) in BALF. In addition, HD-PS-3 reduced the levels of MPO-DNA complex in BALF, decreased citrullinated histone H3 (Cit H3) expression and NET formation (colocalization of MPO, Cit H3, and DNA) in lung tissue. CONCLUSION: An anticomplement homogeneous polysaccharide HD-PS-3 was isolated from H. diffusa. HD-PS-3 exhibited a therapeutic effect against ALI, and the mechanism might be related to its inhibitory effects on complement activation, neutrophil recruitment, and NET formation.

Altered glycan accessibility on native immunoglobulin G complexes in early rheumatoid arthritis and its changes during therapy.

The goal of this study was to investigate the glycosylation profile of native immunoglobulin (Ig)G present in serum immune complexes in patients with rheumatoid arthritis (RA). To accomplish this, lectin binding assays, detecting the accessibility of glycans present on IgG-containing immune complexes by biotinylated lectins, were employed. Lectins capturing fucosyl residues (AAL), fucosylated tri-mannose N-glycan core sites (LCA), terminal sialic acid residues (SNA) and O-glycosidically linked galactose/N-acetylgalactosamine (GalNac-L) were used. Patients with recent-onset RA at baseline and after 3-year follow-up were investigated. We found that native IgG was complexed significantly more often with IgM, C1q, C3c and C-reactive protein (CRP) in RA patients, suggesting alterations of the native structure of IgG. The total accessibility of fucose residues on captured immune complexes to the respective lectin was significantly higher in patients with RA. Moreover, fucose accessibility on IgG-containing immune complexes correlated positively with the levels of antibodies to cyclic citrullinated peptides (anti-CCP). We also observed a significantly higher accessibility to sialic acid residues and galactose/GalNAc glyco-epitopes in native complexed IgG of patients with RA at baseline. While sialic acid accessibility increased during treatment, the accessibility of galactose/GalNAc decreased. Hence, successful treatment of RA was associated with an increase in the SNA/GalNAc-L ratio. Interestingly, the SNA/GalNAc-L ratio in particular rises after glucocorticoid treatment. In summary, this study shows the exposure of glycans in native complexed IgG of patients with early RA, revealing particular glycosylation patterns and its changes following pharmaceutical treatment.

Eupatorium lindleyanum DC. flavonoids fraction attenuates lipopolysaccharide-induced acute lung injury in mice.

Eupatorium lindleyanum DC., "Ye-Ma-Zhui" called by local residents in China, showed anti-inflammatory activity and is used to treat tracheitis. We had isolated and identified the flavonoids, diterpenoids and sesquiterpenes compounds from the herb. In the present study, we evaluated the protective effects of the flavonoids fraction of E. lindleyanum (EUP-FLA) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice and the possible underlying mechanisms of action. EUP-FLA could significantly decrease lung wet-to-dry weight (W/D) ratio, nitric oxide (NO) and protein concentration in BALF, lower myeloperoxidase (MPO) activity, increase superoxide dismutase (SOD) activity and down-regulate the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1ß (IL-1ß). Additionally, EUP-FLA attenuated lung histopathological changes and significantly reduced complement deposition with decreasing the levels of Complement 3 (C3) and Complement 3c (C3c) in serum. These results demonstrated that EUP-FLA may attenuate LPS-induced ALI via reducing productions of pro-inflammatory mediators, decreasing the level of complement and affecting the NO, SOD and MPO activity.

The IgG "lupus-band" deposition pattern of pemphigus erythematosus: association with the desmoglein 1 ectodomain as revealed by 3 cases.

BACKGROUND: Pemphigus foliaceus is an autoimmune skin disease characterized by subcorneal blistering and IgG antibodies directed against desmoglein 1. In the skin, these antibodies deposit intraepidermally. On rare occasions,an additional "lupus band" of granular depositions of IgG and complement is seen along the epidermal basement membrane zone. This combined pattern has been connected with a variant of pemphigus foliaceus named pemphigus erythematosus. OBSERVATIONS: We describe 3 pemphigus foliaceus cases in which phototherapy was administered after a misdiagnosis of psoriasis. This treatment resulted in a flare of skin lesions. Direct immunofluorescence of skin biopsy specimens that were obtained several weeks later demonstrated intraepidermal and granular basement membrane zone depositions. The basement membrane zone depositions consisted of IgG, complement, and the ectodomain of desmoglein 1 and were located below the lamina densa. CONCLUSIONS: High doses of UV light are likely to induce the cleaving of the desmoglein 1 ectodomain. In patients with pemphigus foliaceus, the circulating anti­desmoglein 1 antibodies precipitate this cleaved-off ectodomain along the basement membrane zone, resulting in a lupus band­like appearance. In pemphigus erythematosus, a similar mechanism may be active, which might explain the lupus-band phenomenon.

Characterization of estrogenicity of phytoestrogens in an endometrial-derived experimental model.

Severe developmental and reproductive disorders in wild animals have been linked to high exposure to persistent environmental chemicals with hormonal activity. These adverse effects of environmental estrogens have raised considerable concern and have received increasing attention. Although numerous chemicals with the capacity to interfere with the estrogen receptor (ER) have been identified, information on their molecular mechanism of action and their relative potency is rather limited. For the endometrium, the lack of information is due to the lack of a suitable experimental model. We investigated the functions of phytoestrogens in an endometrial-derived model, RUCA-I rat endometrial adenocarcinoma cells. The cells were cultured on a reconstituted basement membrane to preserve their functional differentiation and estrogen responsiveness. We assessed the relative binding affinity to the estrogen receptor of the selected phytoestrogens coumestrol, genistein, daidzein, and the putative phytoestrogen mangostin compared to estradiol by a competitive Scatchard analysis. The following affinity ranking was measured: 17beta-estradiol >>> coumestrol > genistein > daidzein >>> mangostin. In addition, we investigated the capacity of these compounds to promote the increased production of complement C3, a well-known estradiol-regulated protein of the rat endometrium. All substances tested increased the production of complement C3, although different concentrations were necessary to achieve equivalent levels of induction compared to estradiol. Mechanistically we were able to demonstrate that the increase of complement C3 production was mediated by primarily increasing its steady-state mRNA level. These findings indicate that RUCA-I cells represent a sensitive model system to elucidate relative potencies and functions of environmental estrogens in an endometrium-derived model.

Enhancing effect of antitumor polysaccharide from Astragalus or Radix hedysarum on C3 cleavage production of macrophages in mice.

Effects of Astragalus polysaccharide (APS) and Radix hedysari polysaccharide (RHPS) on the third component of complement (C3) cleavage production of macrophages in ICR mouse were investigated by the immunofluorescent method. By two hours after intraperitoneal injection of 500 mg/kg of APS or RHPS, there was an obvious increase in the deposition of C3 on peritoneal macrophages. When APS or RHPS was injected 5 times (1 time/day), the proportion of C3 positive macrophages was more than that of 1-time injection. At the same time, the number of peritoneal macrophages also increased. Since C3 cleavage product occurred with the activation of C3, the results suggest that the immuno-potentiating action of APS and RHPS may be related to the activity of mouse complement C3.