RESUMEN
Doublecortin-like kinase 1 (DCLK1) is a microtubule-associated kinase. In murine intestine, DCLK1 marks tuft cells with characteristic microvilli, features of neuroendocrine cells and also quiescent stem cell-like properties. The occurrence and pathological role of DCLK1-positive cells in human intestinal mucosa is unknown. We analysed DCLK1 expression in healthy duodenal, jejunal and colorectal mucosa samples (n = 35), and in duodenal specimens from patients with coeliac disease (n = 20). The samples were immunohistochemically double-stained with DCLK1, and synaptophysin, chromogranin A and Ki-67. Ultrastructure of DCLK1-expressing duodenal cells was assessed using correlative light and electron microscopy. DCLK1 expression was seen in about 1% of epithelial cells diffusely scattered through the intestinal epithelium. Electron microscopy showed that the duodenal DCLK1-positive cells had short apical microvilli similar to neighbouring enterocytes and cytoplasmic granules on the basal side. DCLK1-positive cells were stained with synaptophysin. The number of DCLK1-positive cells was decreased in villus atrophy in coeliac disease. Our findings indicate that in human intestinal epithelium, DLCK1-positive cells form a subpopulation of non-proliferating neuroendocrine cells with apical brush border similar to that in enterocytes, and their number is decreased in untreated coeliac disease.
Asunto(s)
Duodeno/citología , Enterocitos/química , Enterocitos/clasificación , Mucosa Intestinal/citología , Intestino Grueso/citología , Péptidos y Proteínas de Señalización Intracelular/análisis , Yeyuno/citología , Proteínas Serina-Treonina Quinasas/análisis , Adulto , Anciano , Enfermedad Celíaca/patología , Cromogranina A/análisis , Gránulos Citoplasmáticos/ultraestructura , Quinasas Similares a Doblecortina , Enterocitos/ultraestructura , Femenino , Humanos , Inmunohistoquímica , Antígeno Ki-67/análisis , Masculino , Microscopía , Microvellosidades/ultraestructura , Persona de Mediana Edad , Sinaptofisina/análisis , Adulto JovenRESUMEN
The enterocyte brush border of the small intestine is a highly specialized membranedesigned to function both as a high capacity digestive/absorptive surface ofdietary nutrients and a permeability barrier towards lumenal pathogens. It is characterizedby an unusually high content of glycolipids (~30% of the total microvillarmembrane lipid), enabling the formation of liquid ordered microdomains, betterknown as lipid rafts. The glycolipid rafts are stabilized by galectin-4, a 36 kDa divalentlectin that cross-links galactosyl (and other carbohydrate) residues present onmembrane lipids and several brush border proteins, including some of the majorhydrolases. These supramolecular complexes are further stabilized by intelectin, a 35kDa trimeric lectin that also functions as an intestinal lactoferrin receptor. As a result,brush border hydrolases, otherwise sensitive to pancreatic proteinases, are protectedfrom untimely release into the gut lumen. Finally, anti-glycosyl antibodies, synthesizedby plasma cells locally in the gut, are deposited on the brush border glycolipidrafts, protecting the epithelium from lumenal pathogens that exploit lipid rafts asportals for entry to the organism (AU)
No disponible