# Developmental Regulation of MUC5B
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## Hypothesis:
MUC5B expression is intrinsically attenuated in the infant airway epithelium

## Preliminary data:

1. Time course study
Findings: MUC5B expression expression after 3 weeks of differentiation is significantly higher in adults compared to infants

2. [Immunofluorescence for MUC5B](https://ucdavis.app.box.com/folder/95576691435)
Findings: MUC5B protein expression agrees with mRNA expression results found in 1

## Experiments

### 1. Immunofluorescence
[Protocol](https://ucdavis.app.box.com/file/612080892171)
**Rational**: The human conducting airway is primarily lined with a pseudostratified epithelium consisting of cilliated, club, and goblet cells. These and other epithelial cells expressed in the airways are involved in mucocilliary clearance-- a mechanism that actively removes microbes and particulate matter for the lung. We recently found MUC5B expression in adult (age > 3 years) TBEs following 3 weeks of differentiation is significantly higher than infants (age <12 months). It was originally thought that adults have a higher propensity to express MUC5B however, we have not ruled out whether adults are more prone to differentiation compared to infants. If true it is possible that adults express more MUC5B solely because they express more mucous secreting cells, goblet cells.

**Proposal**: Conduct Immunofluorescence for alpha-tubulin (commonly used identify differentiating cells)

Pros:
1. We have slides prepared from animals over varying ages
2. I have a lot of experience doing Immunofluorescence

Cons:
1. expense of purchasing a new antibody

**Alternative Proposal**:: Conduct as western blot from protein isolated from medcull animals. If I use this experiment I would need at least 3 infant and adult TBE samples to indicate a trend may be a physiological one

Cons:
1. Will take longer
2. I have less experience with this technique
3. We will not able to observe a site specific phenomena (goblet cells are primarily expressed in the large airways)

**What information can this gain?**

## [Animals](https://ucdavis.app.box.com/file/571626956230)

|RDU ID|MMU ID|Project ID|Age (yrs)|Prior Treatments|Experiment|
| --------- | --------- | ---------- | --------- | ---------------- | ------------------ |
|33009|98 |IAM04|1|None|MUCBIF|
|33016|100|IAM04|1|None|MUCBIF|
|29028|01 |MAM01|3|None|MUCB, α-Tubulin IF|
|28776|03 |MAM01|3|None|MUCB IF|
|30537|50 |MAM02|3|None|MUCB IF|
|33015|99 |IAM04|1|None|MUCB IF|

## References
1. [Rayner et al., 2019](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6346027/pdf/41598_2018_Article_36735.pdf)
2. [Whitsett et al., 2018](https://www.atsjournals.org/doi/pdf/10.1513/AnnalsATS.201802-128AW)