Chitin and chitinase: Role in pathogenicity, allergenicity and health

Interleukin-6 Neutralization by Antibodies Immobilized at the Surface of Polymeric Nanoparticles as a Therapeutic Strategy for Arthritic Diseases

Arthritic diseases are disabling conditions affecting millions of patients worldwide. Pro-inflammatory cytokines, particularly interleukin-6 (IL-6), plays a crucial role in inflammation and cartilage destruction. Although the beneficial effects of antibody therapy, its efficacy is limited. Therefore, this work proposes the immobilization of antibodies at the surface of biodegradable polymeric nanoparticles (NPs) to capture and neutralize IL-6. Our system is intended to protect, extend and enhance the therapeutic efficacy after delivery. Chitosan-hyaluronic acid NPs are synthesized as a stable monodisperse population. After determining the maximum immobilization capacity (10 μg/mL), the capture ability was confirmed. Biological assays demonstrate the NPs cytocompatibility with human articular chondrocytes (hACs) and human macrophages. hACs stimulated with macrophage conditioned medium shows the beneficial role of IL-6 capture and neutralization. Biofunctionalized NPs exhibit a prolonged action and stronger efficacy than the free antibody. In conclusion, this system can be an effective and long lasting treatment for arthritic diseases.

Immuno-enhancement effect of polysaccharide extracted from Stichopus japonicus on cyclophosphamide-induced immunosuppression mice

Polysaccharide (SJP) was extracted from Sea cucumber, Stichopus japonicas, and its immune-enhancing activities were evaluated in vivo immune-suppressed mice systems. Cyclophosphamide(CY)-treated mice were orally administrated with SJP according to different concentrations. The results showed that administration of SJP significantly increased spleen index without variation of the body weight, compared to only CY treatment group. The proliferation of splenic lymphocyte and NK activity was also stimulated by SJP. In addition, the oral administration of SJP up-regulated COX-2 and TLR-4 as well as cytokines such as IL-1β, IL-4, IL-6, IL-10, TNF-α and IFN-γ, which are secreted from splenic lymphocytes in cyclophosphamide-treated mice. Moreover, our results showed that SJP stimulated macrophages via NF-κB and MAPK signaling pathways. These findings provided the potential use of SJP as an alternative means under immune-suppressed conditions, and furthermore can be utilized as a functional material for food and pharmaceutical industries.

Microglial/macrophage markers CHI3L1, sCD14, and sCD163 in CSF and serum of pediatric inflammatory and non-inflammatory neurological disorders: A case-control study and reference ranges

OBJECTIVE

To assess the role of microglia and macrophages in neuroinflammatory disorders in children via biomarkers, and establish control reference ranges.

METHODS

In an IRB-approved case-control study of 98 children, the concentrations of CSF/serum CHI3L1, sCD14, and sCD163 were measured by ELISA. Groups were controls (non-inflammatory neurological disorders, NIND, n=37), opsoclonus-myoclonus syndrome (OMS, n=37), and other inflammatory neurological disorders (OIND, n=24).

RESULTS

In control CSF, median concentrations (ng/ml) were 25 (IQR 16,41) for CHI3L1 and 42 (26,160) for sCD14; in serum, 16 (12,22) for CHI3L1, and 431 (270,957) for sCD163. The median CSF concentration of CHI3L1 in OIND was significantly higher than controls (2.9-fold, P<0.0001) and OMS (1.6-fold higher than controls, NS). The CSF sCD14 concentration was 1.9-fold higher in OIND (P=0.008) and 1.4-fold higher in OMS than controls. sCD163, below detection limits in CSF, was not significantly increased in OIND or OMS sera.

CONCLUSIONS

CSF CHI3L1 and sCD14 elevations hold promise as immunomarkers in pediatric OIND, especially in high-expression individuals. These results provide evidence of innate immune system involvement in several pediatric neuroinflammatory disorders. Pediatric control data on CSF microglia/macrophage activation markers are hereby available for other investigators.

Biochemical characterization of a novel thermostable chitinase from Hydrogenophilus hirschii strain KB-DZ44

An extracellular acido-thermostable endo-chitinase (called ChiA-Hh59) from thermophilic Hydrogenophilus hirschii strain KB-DZ44, was purified and characterized. The maximum chitinase activity recorded after 36-h of incubation at 60°C was 3000U/ml. Pure enzyme was obtained after heat and acidic treatment, precipitation by ammonium sulphate and acetone, respectively, followed by sequential column chromatographies on Sephacryl S-200 and Mono Q-Sepharose. Based on Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis, the purified enzyme is a monomer with a molecular mass of 59103.12-Da. The 22 residue NH₂-terminal sequence of the enzyme showed high homology with family-18 bacterial chitinases. The optimum pH and temperature values for chitinase activity were pH 5.0 and 85°C, respectively. The pure enzyme was completely inhibited by p-chloromercuribenzoic acid (p-CMB) and N-ethylmaleimide (NEM). The obtained results suggest that ChiA-Hh59 might be an endo-chitinase. The studied chitinase exhibited high activity towards colloidal chitin, chitin azure, glycol chitin, while it did not hydrolyse chitibiose and amylose. Its K_m and k_cat values were 0.298mg colloidal chitin/ml and 14400s^-1, respectively. Its catalytic efficiency was higher than those of chitodextrinase and ChiA-65. Additionally, Thin-layer chromatography (TLC) analysis from chitin-oligosaccharides showed that ChiA-Hh59 acted as an endo-splitting enzyme. In conclusion, this chitinase may have great potential for the enzymatic degradation of chitin.

In silico analysis of ChtBD3 domain to find its role in bacterial pathogenesis and beyond

Chitin binding domain 3, known by the acronym ChtBD3, is a domain in the enzymes and proteins of several pathogenic virus, bacteria and fungi. As this domain is evolutionarily-conserved in virulence factors of these infectious agents, its detailed investigation is of clinical interest. In this regard, the current in silico study analyzed ChtBD3 domain distribution in bacterial proteins present in publicly-available SMART (simple modular architecture research tool) database. Also, the co-occurring domains of ChtBD3 in the studied proteins were mapped to understand positional rearrangement of the domain and consequent functional diversity. Custom-made scripts were used to interpret the data and to derive patterns. As expected, interesting results were obtained. ChtBD3 domain co-occurred with other critical domains like peptidase, glycol_hydrolase, kinase, hemagglutinin-acting, collagen-binding, among others. The findings are expected to be of clinical relevance.

Inflammasomes, the cardinal pathology mediators are activated by pathogens, allergens and mutagens: A critical review with focus on NLRP3

Inflammation is a pivotal defense system of body. Unfortunately, when homeostasis falters, the same inflammatory mechanism acts as a double-edged sword, and turns offensive, paving the path for a broad array of pathologies. A multi-protein complex termed as inflammasome perceives the PAMPs (pathogen associated molecular patterns) and DAMPs (danger associated molecular patterns), executing immune responses. This activation predominantly encompasses the elaboration of effector cytokines IL-1β, IL-18, and the cysteine proteases (caspase 1 and 11). Extensive study on an inflammasome NLRP3 has revealed its role in the onset and progression of pathogenic, metabolic, autoimmune, neural, and geriatric diseases. In this regard, this inflammasome's immune activation mechanisms and inhibition strategies have been discussed. Through this rigorous literature analysis, the superficial diversity between pathogens/allergens and mutagens, and NLRP3 activity towards them has been emphasized. Though there is a scope for inhibition of aberrant inflammasomes, including that of NLRP3, given their complexity and unpredictability, prevention of their activation by lifestyle correction has been suggested.

Biomedical applications of natural-based polymers combined with bioactive glass nanoparticles

The combination of natural polymers with nanoparticles allowed the development of functional bioinspired constructs. This review discusses the composition, design, and applications of bioinspired nanocomposite constructs based on bioactive glass nanoparticles (BGNPs).