Structural heart papers

Question 1

In Zhou/Wu’s Recounting Cardiac Cellular composition paper, what Ab did they use to label CMs, ECs and fibroblasts?

Answer 1

CMs - MHCa (myosin heavy chain alpha)
ECs - Aka platelet endothelial cell adhesion molecule 1 (PECAM-1)
Fibroblast - DDR2 (Discoidin Domain Receptor 2), receptor tyrosine kinase that binds to fibrillar collagen expressed in mesenchymal cells eg fibroblasts and myofibroblasts

Question 2

Wnt/B-catenin signaling pathway

Answer 2

In canonical Wnt/B-catenin pathway:
- without Wnt, B-catenin is bound to destruction complex (including Axin, APC, GSK-3b, and CK1), promoting B-catenin phosphorylation and targeting for ubiquitination
- with Wnt, Wnt ligand binds to Frizzled receptor (Fzd) and LRP5/6 coreceptor on cell surface, inhibiting the destruction complex, preventing B-catenin degradation. B-catenin translocates to nucleus and binds to TCF/LEF transcription factors, promoting transcription

Question 3

Developmental biology of LV and RV (and which genes they express?) - Dark LV paper

Answer 3

LV - from mid-streak –> coalesce into 1st heart field, expresses TBX5, HCN4, and NKX2.5

RV - from late streak –> 2nd heart filed, expresses ISL1

Question 4

Markers used by Dark et al for atrial CMs

Answer 4

NR2F2 and HOXB4 (downstream of RA signalling)