Intestinal tuft cells regulate the ATM mediated DNA Damage response via Dclk1 dependent mechanism for crypt restitution following radiation injury

Abstract

Crypt epithelial survival and regeneration after injury require highly coordinated complex interplay between resident stem cells and diverse cell types. The function of Dclk1 expressing tuft cells regulating intestinal epithelial DNA damage response for cell survival/self-renewal after radiation-induced injury is unclear. Intestinal epithelial cells (IECs) were isolated and purified and utilized for experimental analysis. We found that small intestinal crypts of VillinCre;Dclk1f/f mice were hypoplastic and more apoptotic 24 h post-total body irradiation, a time when stem cell survival is p53-independent. Injury-induced ATM mediated DNA damage response, pro-survival genes, stem cell markers, and self-renewal ability for survival and restitution were reduced in the isolated intestinal epithelial cells. An even greater reduction in these signaling pathways was observed 3.5 days post-TBI, when peak crypt regeneration occurs. We found that interaction with Dclk1 is critical for ATM and COX2 activation in response to injury. We determined that Dclk1 expressing tuft cells regulate the whole intestinal epithelial cells following injury through paracrine mechanism. These findings suggest that intestinal tuft cells play an important role in regulating the ATM mediated DNA damage response, for epithelial cell survival/self-renewal via a Dclk1 dependent mechanism, and these processes are indispensable for restitution and function after severe radiation-induced injury.

Optimized multiplex immunofluorescence single-cell analysis reveals tuft cell heterogeneity

“…Despite this, little change was observed in tuft cell protein expression profiles. Tuft cell stability under these conditions is consistent with the long-lived nature of tuft cells relative to other differentiated intestinal cell types (16); tuft cell resistance to apoptosis following other insults, such as radiation (38), compared with other the other differentiated intestinal cell types; and the role of DCLK1-positive tuft cells in intestinal regeneration (42)(43)(44). Therefore, the enrichment of tuft cells in the intestinal epithelium after fasting is likely due to tuft cell persistence, compared with other intestinal cells, rather than proliferation of existing tuft cells.…”

“…Other studies have observed increased oxidative stress following fasting in other organ sites (45), which can lead to increased Cox2 expression (46). Furthermore, Chandrakesan et al showed that tuft cells regulate Cox2 signaling through a DCLK1-dependent paracrine response to intestinal injury (44).…”

The Immune Function of Tuft Cells at Gut Mucosal Surfaces and Beyond

“…Based on Trpm5-GFP reporter, all tuft cells in intestine (63,68) and nasal cavity (75,80) express TRPM5. GNAT3…”

“…In particular, how is the circuit regulated if IL-25 expression is constitutive, and what do tuft cells do besides secrete IL-25? Besides cytokines, tuft cells also express enzymes for eicosanoid biosynthesis, such as Cox-1, Cox-2, 5-lipoxygenase (Alox5), and hematopoietic PG-D synthase (Hpgds) (7,14,46,(66)(67)(68). How eicosanoid biosynthesis is regulated in tuft cells and the physiologic function of tuft cell-derived eicosanoids remains unknown.…”

DCLK1 Expression in Colorectal Polyps Increases with the Severity of Dysplasia

“…In a study on CRC metastasis, Gao et al reported that DCLK1 expression was significantly increased in primary CRC and in lymphatic metastases compared with normal colorectal specimens, and moreover, DCLK1 mRNA levels in CRC were significantly correlated with lymph node metastasis and TNM stage (10). DCLK1 expression has also been strongly associated with EMT (18,20). Although a number of genetic studies on DCLK1 have been reported, only few reports have investigated the behavior and distribution of DCLK1 expression in human CRC tissues.…”