The role of human breast milk mucus and mucins in HIV-AIDS

Includes abstract.Includes bibliographical references.Milk molecules such as mucins, antibodies, bactericidal enzymes like lysozymes and fatty acids that lyse bacteria, viral particles and bacterial peptides, offer anti-microbial activity in milk. Despite human breast milk being rich in anti-microbial substances, such as mucin, that protect against pathogens and viruses, it remains a significant route of HIV transmission from mother to child. ... The objectives of the study were to isolate, purify, identify and investigate the anti-HIV-1 activity of crude breast milk particularly the human milk fat globule material (MFGM) and its purified mucin components, in HIV positive patients (n = 20) compared with those who are not infected (n = 20). This study also tested the effect that heat (80°C, 10 min) might have on breast milk which might release the milk mucins and consequently have an inhibitory effect on HIV-1

Decrease of core 2 O-glycans on synovial lubricin in osteoarthritis reduces galectin-3 mediated crosslinking

The synovial fluid glycoprotein lubricin (also known as proteoglycan 4) is a mucin-type O-linked glycosylated biological lubricant implicated to be involved in osteoarthritis (OA) development. Lubricin\u27s ability to reduce friction is related to its glycosylation consisting of sialylated and unsialylated Tn-antigens and core 1 and core 2 structures. The glycans on lubricin have also been suggested to be involved in crosslinking and stabilization of the lubricating superficial layer of cartilage by mediating interaction between lubricin and galectin-3. However, with the spectrum of glycans being found on lubricin, the glycan candidates involved in this interaction were unknown. Here, we confirm that the core 2 O-linked glycans mediate this lubricin-galectin-3 interaction, shown by surface plasmon resonance data indicating that recombinant lubricin (rhPRG4) devoid of core 2 structures did not bind to recombinant galectin-3. Conversely, transfection of Chinese hamster ovary cells with the core 2 GlcNAc transferase acting on a mucin-type O-glycoprotein displayed increased galectin-3 binding. Both the level of galectin-3 and the galectin-3 interactions with synovial lubricin were found to be decreased in late-stage OA patients, coinciding with an increase in unsialylated core 1 O-glycans (T-antigens) and Tn-antigens. These data suggest a defect in crosslinking of surface-active molecules in OA and provide novel insights into OA molecular pathology

Recombinant mucin-type proteins as tools for studies on the interactions between Helicobacter pylori and its carbohydrate receptors

Glycan-protein interactions are important in pathogen adhesion and infections. H. pylori has adhesins which enables it to bind to glycans on the gastric mucosa and, in the long run, cause gastric cancer. The reported current antibiotic regimen used in the treatment to eradicate H. pylori fails in 20% of the patients. A multivalent glycan inhibitor could offer a suitable alternative to antibiotics by acting as a competitive inhibitor for the cell receptors, leading to the binding and elimination of the microbe. This thesis is focused around the use of genetically engineered CHO-K1 cells producing a recombinant mucin-type fusion protein, P-selectin glycoprotein ligand-1/mouse IgG2b (PSGL-1/mIgG2b), which is used as a scaffold for multivalent presentation of engineered bioactive O-linked glycans. Through the engineering of carbohydrate determinants mediating attachment or affecting the growth of H. pylori, potential inhibitors of H. pylori infection were created (paper I, II and III).In paper I, we show that Β4GALNT3 added a β1,4-linked GalNAc to GlcNAc (LDN) irrespective of whether the latter was carried by a core 2, core 3 or extended core 1 chain. There was no correlation between H. pylori binding and the expression of LDN determinants on gastric mucins or a mucin-type fusion protein carrying core 2, 3 and extended core 1 O-glycans. In paper II, The H. pylori experiments demonstrated that only PSGL-1/mIgG2b proteins with Leb on core 3 inhibited BabA-mediated binding. On the other hand, the series of sialylated PSGL-1/mIgG2b proteins all demonstrated various degrees of inhibition of SabA-mediated binding, suggesting that SabA accepts various substitution of sLex for binding. In paper III, we show by Western blot and LC-MS/MS that core 1, core 2, core 3 and extended core 1 chains could all carry the GlcNAcα4Gal determinant following transient transfection of CHO-K1 cells. Preliminary results showed that PSGL-1/mIgG2b carrying the GlcNAcα4Gal-terminal on core 1 and core 2 O-glycans did not inhibit the growth of H. pylori. In paper IV, we show that the interaction of galectin-3 with the lubricating protein, lubricin, derived from osteoarthritis as opposed to healthy joints is dependent on core 2 O-glycans. In conclusion, we have shown that glyco-engineering of a mucin-type fusion protein in CHO-K1 cells generates a powerful tool for investigations on O-glycan biosynthesis and microbial, in this case H. pylori, adhesion. The use of a mucin-type fusion protein as a carrier of frequent O-glycan substitution not only may increase the avidity of the reporter protein for its binding partner under study, but in addition mimics the structural context in which bioactive carbohydrate determinants are presented and used as microbial attachment sites at our mucosal surfaces

Challenges and opportunities experienced by people with a physical disability in Alexandra, Gauteng

School of human and community development, faculty of humanities department of social work, university of Witwatersrand, Johannesburg, South Africa.Physical disability can interfere significantly with the functional adaptation and emotional wellbeing of people with disability and their families. While adjustment to physical disability varies across people, research has shown that physical disability can contribute to widespread disability and impairment in physical functioning for most people over time. Research evidence indicates that people with a physical disability are frequently exposed to marginalisation and stigmatisation within society. However, limited research focused on both the challenges and opportunities experienced by people with physical disability, especially in disadvantaged communities. The primary aim for this study was to explore the challenges and opportunities encountered by people with a physical disability residing in Alexandra, Gauteng. This study adopted the qualitative research design to gather information or data. The type of qualitative design that was employed in this study was the phenomenological approach where the researcher focused on lived experiences of the participants related to topic being researched. The method used to gather data was face-to-face where the research tool was the semi-structured interviews were employed to collect information from research participants. Findings were analysed using a thematic analysis. Approximately 10 adults with a physical disability were purposively selected from Alexandra Disability Centre, which is sanctioned to render services to people with a physical disability. It is envisaged that the research findings will yield to insights to people with physical disability challenges and recommendations that can assist people who render services to people with physical disability were made regarding how they can be treated and encouraged in communities. Keywords: physical disability, challenges, opportunities, empowerment, employmentGR201

Mucus and Mucins: do they have a role in the inhibition of the human immunodeficiency virus?

Background: Mucins are large O-linked glycosylated proteins which give mucus their gel-forming properties. There are indications that mucus and mucins in saliva, breast milk and in the cervical plug inhibit the human immunodeficiency virus (HIV-1) in an in vitro assay. Main body of abstract: Crude mucus gels form continuous layers on the epithelial surfaces of the major internal tracts of the body and protect these epithelial surfaces against aggressive luminal factors such as hydrochloric acid and pepsin proteolysis in the stomach lumen, the movement of hard faecal pellets in the colon at high pressure, the effects of shear against the vaginal epithelium during intercourse and the presence of foreign substances in the respiratory airways. Tumour-associated epitopes on mucins make them suitable as immune-targets on malignant epithelial cells, rendering mucins important as diagnostic and prognostic markers for various diseases, even influencing the design of mucin-based vaccines. Sub-Saharan Africa has the highest prevalence of HIV-AIDS in the world. The main points of viral transmission are via the vaginal epithelium during sexual intercourse and mother-to-child transmission during breast-feeding. There have been many studies showing that several body fluids have components that prevent the transmission of HIV-1 from infected to non-infected persons through various forms of contact. Crude saliva and its purified mucins, MUC5B and MUC7, and the purified mucins from breast milk, MUC1 and MUC4 and pregnancy plug cervical mucus (MUC2, MUC5AC, MUC5B and MUC6), inhibit HIV-1 in an in vitro assay. There are conflicting reports of whether crude breast-milk inhibits HIV-1 in an in vitro assay. However studies with a humanised BLT mouse show that breast-milk does inhibit HIV and that breast-feeding is still advisable even amongst HIV-positive women in under-resourced areas, preferably in conjunction with anti-retroviral treatment. Conclusion: These findings raise questions of how such a naturally occurring biological substance such as mucus, with remarkable protective properties of epithelial surfaces against aggressive luminal factors in delicate locations, could be used as a tool in the fight against HIV-AIDS, which has reached epidemic proportions in sub-Saharan Africa