- Victoria Timbrell, QUT,
- Saeideh Hajigahsemi, QUT
Pollen allergy is a common seasonal respiratory disease triggered by hypersensitivity to pollen affecting 10-30% of adults and 40% of children, and is a predisposing factor for asthma. The sources of grass pollens differ between climate zones with subtropical grass pollens such as Bahia grass (Paspalum notatum), Johnson grass (Sorghum halepense) and Bermuda grass (Cynodon dactylon) being abundant in Queensland.
Pollens interact with airway epithelium to stimulate both adaptive and innate immunity. Proteolytic activity is one route that stimulates release of alarmins and pro-inflammatory cytokines from mucosal epithelia.
Previous studies have found the expression of Serine/Cysteine (Ser/Cys) proteases in some types of grass pollen grains, but it is not clear whether there occur in Bahia or Johnson grass pollen. Better understanding of the interaction between subtropical grass pollen and airway epithelium may also provide insight into interaction between grass pollen grains and certain infectious agents including SARS CoV 2.
This virus is an enveloped RNA virus being surrounded by Spike (S) proteins on its surface which contribute to viral entry. The S1 subunit encompasses the receptor-binding domain (RBD) and the S2 subunit includes the fusion peptide. After binding to angiotensin-converting enzyme 2 (ACE-2) receptor by the RBD of S1, the fusion peptide is processed by transmembrane protease serine 2 (TMPRSS2).
Evidence suggests that the inhibition of Ser/Cys proteases in vitro reduces SARS-CoV-2 viral infectivity. Separately it was found that there might be a positive relationship between pollen concentration and the number of COVID-19 positive cases in different countries.
The aim of this VRES project is to investigate the presence in the transcriptome of Bahia grass pollen, and possible interactions between Ser/Cys proteases and S proteins on SARS-CoV-2 to better understand the effect of allergen exposure on COVID-19 infection in subtropical regions.
Research activities include:
- Literature search and review
- Laboratory experiments
- Data analysis.
You will start with the field collection of fresh Bahia grass pollen. Then, total RNA will be extracted from the field and and frozen pure pollen samples. The quality of extracted RNA will be visualised by agarose gel electrophoresis and confirmed by an Agilent 2100 Bioanalyzer. You will generate cDNA and use bioinformatic approaches to generate gene specific primers for proteases of related grass pollens to amplify transcripts of interest from Bahia grass pollen cDNA samples. Further, total Bahia grass pollen transcriptome sequencing and analysis will be performed.
Skills and experience
You will need to have prior knowledge of molecular biology techniques and some knowledge of immunology.
You will use bioinformatic analysis, and molecular biology techniques including RNA extraction, cDNA synthesis and PCR. Depending on outcomes, if a new cysteine protease molecule in Bahia grass pollen is discovered then there will be options to develop subsequent studies to determine the biochemical function and immunological significance of the protein with respect to pollen allergy and interaction with respiratory virus entry.
You will be supervised by Prof Janet Davies and will work closely on a day to day basis with co-supervisors Saeideh for project theory and analysis, and Vicky for experimental support in the laboratory.
- ollen allergy
- allergic rhinitis
- allergic asthma
- subtropical grass pollen
- serine protease
- cysteine protease
Contact Professor Janet Davies for more information.