It should also be mentioned that if the idea of chronicles as 'parallel lines' is taken seriously, then there is no proper branching in the Leibnizian model.
The sensation of the fingertip or pulp was re-established through coaptation of the proper branches of the digital dorsal nerves to the digital nerves.
Eosinophils have a function restricted to postnatal mammary development, where they may interact with macrophages to induce proper branching morphogenesis.
These RBPs may serve to modulate expression of components of the cell death/engulfment machinery, achieving a balance between dendrite growth and retraction necessary for proper branching morphogenesis.
As a downstream consequence, epimorphin stimulates the expression of MMPs 2 and 3, which are also required for proper branching morphogenesis.
The VEGF-A receptor, Flk1, promotes angioblast differentiation and is a critical signaling component of epithelial-endothelial cross talk, which is necessary for proper branching morphogenesis (14).
Using a lung explants culture system, we confirmed the causal involvement of WNT signaling mediating the effect of Hmga2-loss-of-function (LOF) and showed that Hmga2 is required for proper branching morphogenesis during the formation of the bronchial tree.
Indeed, recent reports have shown that innervation is required for proper branching (Bower et al., 2014), and while vasculature may not be important for lung branching (Havrilak and Shannon, 2015), others have shown the vascular endothelium is required to induce a branching-like program of isolated airway epithelium in 3D cultures (Franzdóttir et al., 2010).
In contrast, α6β4 integrin is not essential for proper branching morphogenesis in vivo, although in mice lacking α6β4 integrin the rapid advancement of end buds generates a fragile glandular epithelium due to deficiencies in cell BM adhesion, exacerbated in tissue areas of shear stress [ 25].
Notwithstanding this uncertainty, proper branching morphogenesis hinges on the spatial and temporal expression of α2β1 integrin, and its major ligands: types I and IV collagen and laminin, all of which peak during puberty and pregnancy, as shown in a mouse model [ 22].
