Expression and Localization of Aquaporin-1 Along the Intestine of Colostrum Suckling Buffalo Calves

Abstract

Aquaporin-1 (AQP1), a six-transmembrane domain protein, belongs to a highly conserved group of proteins called aquaporins known to regulate permeability across cell membranes. Although the role of AQP1 has been extensively studied, its specific activity along the gastrointestinal tract in animals during early postnatal development is poorly known. This study investigates the expression of AQP1 mRNA and protein in the small and large intestine of water buffalo calves after colostrum ingestion using reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and cellular localization of AQP1 by immunohistochemistry. Our results revealed AQP1 immunoreactivity and the presence of the corresponding mRNA in all the examined tracts of the intestine but with a different cellular localization. Western blotting confirmed the presence of AQP1, with a more intense band in colostrum-suckling animals. These findings offer insights into AQP1 expression in the small and large intestine, suggesting its involvement in osmoregulation in gastrointestinal physiology particularly during the first week after birth in relation to specific maturation of intestinal structures.

Aquaporins in Health and Disease: An Overview Focusing on the Gut of Different Species

“…In addition, in our previous study conducted on buffalo calves fed with colostrum for one week, a different pattern of AQP1, 4, and 5 expression was observed with respect to the control group fed milk. These data indicate that a specific regulation of AQP function and distribution could be achieved according to the nutritional level or the food preference [77,78,79]. …”

“…AQP1-immunoreactivity (IR) was found in endothelial cells of capillaries, small vessels, and central lacteals in the villi of the small intestine in the pig, rat, mouse, and buffalo [10,26,60,70,77,103,104]. In addition, AQP1-IR was also found in the enterocytes of the crypts in the buffalo small intestine [77], in the apical and basolateral membranes of Brunner’s gland cells in the rat duodenum [30], and in enteric neurons of the buffalo, rat, and sheep small intestine [77,105,106].…”

“…In addition, AQP1-IR was also found in the enterocytes of the crypts in the buffalo small intestine [77], in the apical and basolateral membranes of Brunner’s gland cells in the rat duodenum [30], and in enteric neurons of the buffalo, rat, and sheep small intestine [77,105,106]. RT-PCR and Northern blot analysis confirmed AQP1 mRNA expression in the small intestine of buffalo, pigs, and rodents [10,77,103].…”

Expression of AQP1 Was Associated with Apoptosis and Survival of Patients in Gastric Adenocarcinoma

“…AQP1 may also be involved in promoting differentiation of gastric adenocarcinoma [14] . To date, studies have focused on the regulation of AQP1 expression in tumor cells and its role in pathogenesis, growth, metastatic potential and tumor progression [2,20] .…”

“…Exogenous expression of AQP1 in a cell line derived from poorly differentiated human gastric adenocarcinoma, suggesting AQP1 may be involved in differentiation of human gastric adenocarcinoma [12] . AQP1 is widely distributed in endothelial cells of capillaries and small vessels as well as in the central lacteals in the small intestine [12][13][14] . AQP1 is also present in the ductal systems of the pancreas and liver, including the bile duct [13] .…”