Examination of Placenta and Child Saliva Samples Associated with Childhood Allergy Development

Allergic disease has risen to epidemic proportions during recent years. Evidence shows that prenatal events play a critical role in determining disease susceptibility via environmental influences on placental function and fetal programming. We hypothesised that childhood susceptibility to allergy is increased through significant alterations in placental gene expression involved in regulating immune system development. Furthermore, we hypothesised that products of altered placental genes are indirect measures of altered protein concentrations in the saliva of children with allergies. The aim of this PhD thesis was to identify proteins associated with childhood allergy using two sources of biological tissue: placental tissue and child saliva. The long term objectives were to identify proteins that could be measures of allergic risk in placenta and saliva, develop an assay for detection of allergic risk in newborns and target proteins for interventions that prevent allergy onset. Placental tissue and child saliva samples were examined using a proteomic approach involving quantitative label-free comparative mass spectrometry. Data analysis were performed using Mascot database and MaxLFQ software. Placental tissue and saliva from children with no allergy were compared with children with allergic diseases (placenta, n= 16; saliva, n= 18). Using placental samples, 1223 proteins were identified from MaxLFQ analysis. Nineteen proteins were significantly altered in allergic male placentae and 21 proteins were altered in allergic female placentae, relative to non-allergic children. Of these proteins, five candidate placental proteins associated with allergic diseases were validated with Western blot (n=68), which include chloride intracellular channel protein 3, peroxiredoxin-2, haptoglobin and complement C3. Moreover, 14-3-3 protein had very high expression in allergic children and very low expression in the non-allergic group. Using child saliva samples, 177 proteins were identified from MaxLFQ analysis. Of these proteins, six candidate proteins with significant ratio in specific allergic phenotypes were validated with Western blot (n=62). These proteins include salivary 14-3-3, cornulin, involucrin, transferrin, haptoglobin and desmoglein 1. Based on Western blot findings, 14-3-3, cornulin and involucrin proteins were further validated using the Blitz system that uses crude saliva sample for rapid identification and quantitation as a potential non-invasive bedside allergy biomarker screening (n=126). Blitz results demonstrated that these proteins were significantly altered in allergic children with asthmatic mother (high risk of allergy), as compared to non-allergic children with asthmatic mother. Only salivary cornulin was significantly altered in allergic children as compared to non-allergic children regardless of maternal asthma status. Findings revealed that in both placental and saliva samples, 14-3-3 proteins were significantly altered in female allergic children as compared with female non-allergic children. Interestingly, altered expression of some proteins varies in a sex-specific manner, such as observed in haptoglobin and involucrin, and in relation to presence or absence of maternal asthma. In conclusion, our findings indicate that protein expression can be altered in-utero in children who subsequently develop an allergy and altered expression of these proteins is detectable in saliva in early life.

Author dc:creator

• Mohamad Zainal, Nurul Hayati

Advisors dc:contributor.advisor

• Clifton, Vicki
• Hoffmann, Peter
• Tuck, Astrud

• childhood allergy
• prenatal events
• fetal programming
• child sailva
• mass spectrometry
• placental proteins
• salivary proteins

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/2440/132227

OAI identifier oai:identifier

oai:digital.library.adelaide.edu.au:2440/132227