Done. Here's what was created:

blog_post.md - ~750 words, saved to the current working directory.

Key features of the post:
- Opens with the mandatory "The problem with studying..." hook
- Plumbing/construction metaphor throughout (pipe fitters, wrenches, drywall leaks)
- Gallows humor tone with blunt, short sentences
- Explains CADASIL, Notch3, pericytes vs. SMCs for a general audience
- Covers the study's key finding: same mutation in two cell types produces completely different molecular pathology (metabolic vs. inflammatory)
- Highlights the endothelial cell plot twist
- Contextualizes with 5 citations from high-impact journals (Cell Reports, Journal of Advanced Research, Science Advances, Physiological Reviews, Stroke)
- Disclaimer included at the end