Temporal and regional morphological differences as a consequence of FGF-2 deficiency are mirrored in the myenteric proteome

Abstract

The enteric nervous system with its intricate network of neurons and glia shows a high plasticity, which not only changes during pre- and postnatal development, but also with disease or changing dietary habits. FGF as a potent neurotrophic factor in the central nervous system might also play a specific role for the ENS development, FGF-2 knockout and corresponding wild-type mice were histologically and functionally analyzed. FGF-2 knockout mice are viable and thrive normally and do apparently not display any obvious neurological deficit. Morphological differences were studied on whole mount preparations of muscle and submucous layer using either cuprolinic blue or immunohistochemical stainings for the neuronal marker PGP 9.5. Ussing-chamber and isometric muscle contraction experiments were performed on isolated gut wall, respectively muscle preparations. Intravital microscopy with GFP-transfected E. coli bacteria was used to investigate influences upon bacterial translocation. In additional experiments the protein pattern of the isolated myenteric plexus of knockout and wild-type mice were compared using 2D-DIGE technology. The morphometric analysis of the myenteric plexus revealed significant differences between FGF-2 knockout and wild-type animals, resulting in larger neurons in the knock out animals, embedded in less densely packed enteric ganglia. While muscle contractility appeared not to be affected, there was a significant difference in bacterial translocation as well as differences in basal chloride secretion to be seen. The observed morphological differences were reflected in the varying protein patterns, which were revealed by 2D-DIGE. A large number of differentially expressed proteins were found in both colonic and duodenal samples. FGF obviously influences the development of well established gastrointestinal functions by various means, thus leading to minor but significant deficiencies. Whether the revealed deficits in the mucous barrier are indebted to the morphological alterations in the ENS cannot yet be proved, but is very likely.

Transplantation of Enteric Cells into the Aganglionic Rodent Small Intestines

“…Hirschsprung's disease, a congenital aganglionosis that occurs in 1 in 5000 births, results from the failure of neural crest stem cells (NCSCs) migrating from the vagal and sacral neural crests to colonize the gut. This may be due to a loss of function of the receptor tyrosine kinase [5], endothelin-3, or the endothelin receptor-B (EDNRB) [4,[6][7][8][9][10][11][12][13][14][15][16]. Patients with Hirschsprung's disease require surgical intervention and possible long-term parenteral nutrition if the segment of aganglionosis is long enough to cause short bowel syndrome.…”

Balancing on the crest – Evidence for disruption of the enteric ganglia via inappropriate lineage segregation and consequences for gastrointestinal function

“…Mutations in Sprouty2 , an FGF2 antagonist, have been associated with intestinal neuronal dysplasia (IND) in humans (Borghini et al, 2009) and Fgf-2 −/− (Fgf2 tm1Zllr/tm1Zllr ) mice similarly exhibit abnormally large ganglia that contain fewer, but larger, neurons than wild-type mice (Hagl et al, 2008). (Hagl et al, 2012) classified enteric neurons in Fgf-2 −/− mice based on morphology (Hanani and Reichenbach, 1994) and found a significant decrease in calbindin expressing Dogiel Type 2 neurons.…”

“…Additionally, Fgf-2 −/− mice exhibit alterations in chloride secretion and translocation of bacteria across the mucosal barrier. How the ENS modulates permeability to bacterial penetration has not been determined (Hagl et al, 2008). …”

Spiking rate of myenteric neurons recorded from multi‐electrode arrays depending on local microenvironment

“…Escherichia coli bacteria are able to translocate through the gut wall, i.e. in the terminal ileum into the submucosal layer as well as the lamina propria of the intestinal wall [6]. The purpose of the study is to demonstrate the maintenance of extracellular conditions for myenteric neurons in vitro.…”