Tuft Cells: A New Player in Hirschsprung's Disease

Abstract

Introduction “Tuft” cells, also known as brush or caveolated cells, are characteristically fusiform shaped, with a distinct apical “tuft” of microvilli extending into the lumen. Double cortin-like kinase 1 (DCLK1) is a microtubule kinase and is a specific marker of intestinal tuft cells. DCLK1-positive tuft cells have been shown to play a key role in gastrointestinal chemosensation, inflammation, and neurotransmission. DCLK1 and Choline acetyltransferase (ChAT), the enzymes responsible for acetylcholine production, are reported to be coexpressed within the gastrointestinal tract. We designed this study to investigate the hypothesis that DCLK1 gene expression is altered in Hirschsprung's disease (HSCR). Materials and Methods HSCR tissue specimens (n = 6) were collected at the time of pull-through surgery, while control samples were obtained at the time of colostomy closure in patients with imperforate anus (n = 6). Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was undertaken to quantify DCLK1 gene expression, and immunolabeling of DCLK1-positive tuft cells was visualized using confocal microscopy. Results qRT-PCR analysis revealed significant downregulation of the DCLK1 gene in both aganglionic and ganglionic HSCR specimens compared with controls (p < 0.05). Confocal microscopy revealed DCLK1-positive tuft cell expression within the colonic mucosa, with a reduction in expression in both aganglionic and ganglionic HSCR colon compared with controls. Conclusion DCLK1 is significantly downregulated in HSCR colon, suggesting a role for tuft cells in cholinergic neurotransmission of the distal colon. The marked decrease in DCLK1 expression within ganglionic specimens highlights the physiologically abnormal nature of this segment in HSCR patients.

Tuft cells in the pathogenesis of chronic rhinosinusitis with nasal polyps and asthma

“…However, acetylcholine derived from tuft cells and nonneuronal sources has recently been implicated in the regulation of airway smooth muscle tone. 58 Whereas bronchiolar hyperresponsiveness and allergic inflammation are inhibited by vagotomy of parasympathetic nerves in the lungs in a canine model 59 (suggesting that neuronal acetylcholine plays an essential role in the pathogenesis of asthma), acetylcholine derived from tuft cells is still thought to play a role in the pathogenesis of pulmonary diseases, Hirschsprung's disease 60 and several cancers. 61,62 Given that cholinergic bronchoconstriction is an important clinical feature of asthma, tuft cells and innate immune mechanisms of acetylcholine production could provide a new target for novel therapeutic interventions.…”

Tuft Cells and Their Role in Intestinal Diseases

“…However, the identification and characterization of TCs in the human intestinal tract based on marker expression is still awaiting consensus. Two studies (42,43) describe a population of human colonic DCLK1 + TCs, however, Leppänen et al (44) reported that human colonic epithelial DCLK + cells have a morphology similar to absorptive enterocytes rather than a classical TC shape, thus questioning whether DCLK1 marks human TCs. In this context we recently tested a commercially available antibody (ab31704) on human colonic material, and failed to obtain convincing immunolabeling for DCLK1 (23), a conclusion also reached by Banerjee et al (40).…”

“…However, the identification and characterization of TCs in the human intestinal tract based on marker expression is still awaiting consensus. Two studies ( 42 , 43 ) describe a population of human colonic DCLK1 + TCs, however, Leppänen et al. ( 44 ) reported that human colonic epithelial DCLK + cells have a morphology similar to absorptive enterocytes rather than a classical TC shape, thus questioning whether DCLK1 marks human TCs.…”

Acetylcholine From Tuft Cells: The Updated Insights Beyond Its Immune and Chemosensory Functions

“…With increasing evidence highlighting the role of ACh as an autocrine and paracrine hormone, cholinergic targets have drawn widespread attention in pulmonary diseases ( Meurs et al, 2013 ; Voisin et al, 2017 ), Hirschsprung’s disease ( O’Donnell et al, 2020 ) and cancers ( Westphalen et al, 2014 ; Schütz et al, 2015 ; Pozo et al, 2018 ; Friedman et al, 2019 ; Goto et al, 2019 ). Tuft cells, considered as a crucial non-neuronal ACh source, have also been discussed in several disease models.…”

“…A recent study on Hischsprung’s disease (HSCR) suggested a new role of tuft cells ( O’Donnell et al, 2020 ). Using immunolabeling and qRT-PCR analysis, O’Donnell et al (2020) observed a decrease of DCLK1 + tuft cells in human HSCR tissue specimens. The authors supposed that the reduction of tuft cells is, in part, responsible for the bowel dysmotility.…”