Diphtheria toxin receptor–mediated conditional and targeted cell ablation in transgenic mice

Abstract The hematopoietic stem cell (HSC) niche is composed of many different types of support cells including endothelial cells, stromal cells, and osteoblast. Studies that ablated mature osteoblast showed that they might be important to support maintenance of HSCs. These studies used Col2.3ΔTK to ablate differentiated osteoblast with daily treatments of ganciclovir after which the samples were analyzed immediately. Two opposing studies have been done using this system one showing a decrease in HSC and another showing an increase thus the role of osteoblast in HSC maintenance is still unclear. We have used a different method of ablating cells using Osteocalcin (Oc) and Osterix (Osx) Cre to drive expression of a diphtheria toxin receptor (iDTR), in mature osteoblast and osteoprogenitors, respectively. We injected eight week old mice with three doses of diphtheria toxin and analyzed the LSK and LT-HSC populations a month after cell ablation. There was no effect when the osteoprogenitors were ablated using Osx-Cre; suggesting ablation at postnatal stages is likely necessary to see an effect using Oxs-Cre. On the other hand, we found that a month after ablation of the Oc expressing cells the osteoblast population had recovered but the LSK and LT-HSC populations were still affected with an increase in both populations, suggesting that being exposed to a defective niche might have long-term effects on the HSC population. Disclosures No relevant conflicts of interest to declare.

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CD206+ macrophage is an accelerator of endometriotic-like lesion via promoting angiogenesis in the endometriosis mouse model

Scientific Reports ◽

10.1038/s41598-020-79578-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yosuke Ono ◽

Osamu Yoshino ◽

Takehiro Hiraoka ◽

Erina Sato ◽

Akiko Furue ◽

...

Keyword(s):

Mouse Model ◽

Diphtheria Toxin ◽

Immunohistochemical Study ◽

Mrna Levels ◽

Cytokines And Chemokines ◽

Diphtheria Toxin Receptor ◽

Endothelial Cell Marker ◽

Toxin Receptor ◽

Group A

AbstractIn endometriosis, M2 MΦs are dominant in endometriotic lesions, but the actual role of M2 MΦ is unclear. CD206 positive (+) MΦ is classified in one of M2 type MΦs and are known to produce cytokines and chemokines. In the present study, we used CD206 diphtheria toxin receptor mice, which enable to deplete CD206+ cells with diphtheria toxin (DT) in an endometriosis mouse model. The depletion of CD206+ MΦ decreased the total weight of endometriotic-like lesions significantly (p < 0.05). In the endometriotic-like lesions in the DT group, a lower proliferation of endometriotic cells and the decrease of angiogenesis were observed. In the lesions, the mRNA levels of VEGFA and TGFβ1, angiogenic factors, in the DT group significantly decreased to approximately 50% and 30% of control, respectively. Immunohistochemical study revealed the expressions of VEGFA and an endothelial cell marker CD31 in lesions of the DT group, were dim compared to those in control. Also, the number of TGFβ1 expressing MΦ was significantly reduced compared to control. These data suggest that CD206+ MΦ promotes the formation of endometriotic-like lesions by inducing angiogenesis around the lesions.

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