AQP1 in the Gastrointestinal Tract of Mice: Expression Pattern and Impact of AQP1 Knockout on Colonic Function

Abstract

Aquaporin 1 (AQP1) is one of thirteen known mammalian aquaporins. Its main function is the transport of water across cell membranes. Lately, a role of AQP has been attributed to other physiological and pathological functions including cell migration and peripheral pain perception. AQP1 has been found in several parts of the enteric nervous system, e.g., in the rat ileum and in the ovine duodenum. Its function in the intestine appears to be multifaceted and is still not completely understood. The aim of the study was to analyze the distribution and localization of AQP1 in the entire intestinal tract of mice. AQP1 expression was correlated with the hypoxic expression profile of the various intestinal segments, intestinal wall thickness and edema, as well as other aspects of colon function including the ability of mice to concentrate stools and their microbiome composition. AQP1 was found in a specific pattern in the serosa, the mucosa, and the enteric nervous system throughout the gastrointestinal tract. The highest amount of AQP1 in the gastrointestinal tract was found in the small intestine. AQP1 expression correlated with the expression profiles of hypoxia-dependent proteins such as HIF-1α and PGK1. Loss of AQP1 through knockout of AQP1 in these mice led to a reduced amount of bacteroidetes and firmicutes but an increased amount of the rest of the phyla, especially deferribacteres, proteobacteria, and verrucomicrobia. Although AQP-KO mice retained gastrointestinal function, distinct changes regarding the anatomy of the intestinal wall including intestinal wall thickness and edema were observed. Loss of AQP1 might interfere with the ability of the mice to concentrate their stool and it is associated with a significantly different composition of the of the bacterial stool microbiome.

Aquaporins: Gatekeepers of Fluid Dynamics in Traumatic Brain Injury

“…In the peripheral nervous system, AQP1 expression is observed in a subset of primary sensory neurons located in the dorsal root and nodose ganglia of mice [ 48 ]. Furthermore, AQP1 is present in enteric neurons of both mice and rats, indicating its role in the gastrointestinal nervous system, where it likely contributes to fluid transport and neuronal function [ 49 ]. It was also described in the human trigeminal system [ 50 ].…”

AQP1 Deficiency Drives Phthalate-Induced Epithelial Barrier Disruption through Intestinal Inflammation

“…The expression of AQP1 in the villi and the crypt of enterocytes otherwise suggests its role in absorption and secretion . Several studies have demonstrated that the highest level of AQP1 in the gastrointestinal tract was observed in the small intestine, and AQP1 expression was associated with the intestinal wall thickness and other aspects of intestinal function . A recent study found that DEHP exposure induced renal damage through targeted inhibition of AQPs, especially AQP1 .…”

“…17 Several studies have demonstrated that the highest level of AQP1 in the gastrointestinal tract was observed in the small intestine, and AQP1 expression was associated with the intestinal wall thickness and other aspects of intestinal function. 18 A recent study found that DEHP exposure induced renal damage through targeted inhibition of AQPs, especially AQP1. 19 Although the function of AQP1 in the intestine appears to be diverse, the role of AQP1 in DEHP-induced intestinal inflammation and damage is not completely established.…”

Effect of vitamin D₃ and a stinging nettle extract on the gastric tissue of rats administered with trinitrobenzene sulfonic acid

“…2020 ). AQP-1 has been identified in the gastrointestinal tract from the oesophagus to the colon, and in glial cells and neurons in the enteric nervous system ( Volkart et al. 2023 ).…”

“…AQPs are present in almost all living systems and viruses (Ishibashi et al 2020). AQP-1 has been identified in the gastrointestinal tract from the oesophagus to the colon, and in glial cells and neurons in the enteric nervous system (Volkart et al 2023). Although the exact role of AQP-1 in the enteric nervous system remains unclear, it has been linked to pathological mechanisms such as pain https://doi.org/10.17221/111/2023-VETMED sensation, inflammatory responses, hypoxic conditions, and diabetes (Wagner et al 2022).…”