Immunofluorescent staining of colon of Holstein; Nestin-CreERT2; R26R-YFP mice at P20.
The mice were treated with tamoxifen (2mg/ml; 50 μl) by oral gavage from P3 to P8 (P: Post-natal Day). The efficacy of tamoxifen treatment to induce Cre recombinase was tested at P20. We see some Nestin+ cells that are GFP+ (YFP+). Thus, at the molecular level, the dose of tamoxifen introduced by oral gavage appears to be capable of activating Cre recombinase in some Nestin+ cells.
Project description
Hirschsprung’s disease is characterized by the absence of ganglia of enteric nervous system in the colon. To avoid death by constipation and enterocolitis, the only strategy applicable to treat this disease is the surgical removal of the affected area.
The Pilon laboratory has developed an alternative regenerative strategy of enteric ganglia at the aganglionnal zone in different mouse models and in human patient tissues. This approach is based on the administration of GDNF, a powerful neurotrophic factor. We found that about 35% of the neoformed ganglia are derived from Schwann cells. We therefore seek to identify the other cell types that generate 65 % of ganglia by a cell tracking using the Cre/Loxp genetic system. Enteric glial cells are suspected to be a target of GDNF. To confirm this, three triple-transgenic mouse lines with tamoxifen-inducible Cre-ERT2 recombinase expression were generated. Studies are underway to determine optimal tamoxifen doses. Ganglia formation is evaluated by immunofluorescence.
We are also studying the effect of GDNF on the immune system of the colon by flow cytometry. The choice of the optimal method of cell dissociation of mouse colons as well as markers of myeloid and lymphoid cells was made. At the same time, we aim to continue studying the other curative aspects of GDNF, including the composition of the intestinal flora in our mice models. This allows us to consider that our treatment will be effective for patients with Hirschsprung’s disease.
Research team
Name: Neija Lassoued, M.Sc
Supervisor: Nicolas Pilon (UQAM)
Laureate: Doctoral scholarship 2019 and 2020