Chitinase mRNA Levels Determined by QPCR in Crab-Eating Monkey (Macaca fascicularis) Tissues: Species-Specific Expression of Acidic Mammalian Chitinase and Chitotriosidase

Abstract

Mice and humans express two active chitinases: acidic mammalian chitinase (AMCase) and chitotriosidase (CHIT1). Both chitinases are thought to play important roles in specific pathophysiological conditions. The crab-eating monkey (Macaca fascicularis) is one of the most frequently used nonhuman primate models in basic and applied biomedical research. Here, we performed gene expression analysis of two chitinases in normal crab-eating monkey tissues by way of quantitative real-time polymerase chain reaction (qPCR) using a single standard DNA molecule. Levels of AMCase and CHIT1 messenger RNAs (mRNAs) were highest in the stomach and the lung, respectively, when compared to other tissues. Comparative gene expression analysis of mouse, monkey, and human using monkey–mouse–human hybrid standard DNA showed that the AMCase mRNA levels were exceptionally high in mouse and monkey stomachs while very low in the human stomach. As for the CHIT1 mRNA, we detected higher levels in the monkey lung when compared with those of mouse and human. The differences of mRNA expression between the species in the stomach tissues were basically reflecting the levels of the chitinolytic activities. These results indicate that gene expression of AMCase and CHIT1 differs between mammalian species and requiring special attention in handling data in chitinase-related studies in particular organisms.

Noninsect-Based Diet Leads to Structural and Functional Changes of Acidic Chitinase in Carnivora

“…Acidic chitinase (Chia; also referred to acidic mammalian chitinase, “AMCase”; Boot et al 2001 , 2005 ) hydrolyzes the β-1, 4 glycoside bonds of chitin, a major structural polysaccharide in insects ( Bueter et al 2013 ; Wysokowski et al 2015 ; Van Dyken and Locksley 2018 ). Chia is expressed in the stomachs of insectivorous and omnivorous animals including bat ( Strobel et al 2013 ), mouse ( Ohno et al 2016 ), pangolin ( Ma et al 2018 ), crab-eating monkey ( Uehara et al 2018 , 2021 ), and common marmoset ( Tabata, Kashimura, et al 2019 ). In addition, omnivorous livestock animals, such as chicken and pig, express Chia at high levels in their stomachs and are able to degrade chitin and chitin-containing materials such as shrimp shells and mealworm larvae shells under normal gastrointestinal conditions ( Tabata, Kashimura, Wakita, Ohno, Sakaguchi, Sugahara, Imamura, et al 2017 ; Tabata, Kashimura, Wakita, Ohno, Sakaguchi, Sugahara, Kino, et al 2017 ; Tabata, Kashimura, Wakita, et al 2018 ; Tabata, Wakita, et al 2019 ).…”

<p>Chitinases and Chitinase-Like Proteins in Obstructive Lung Diseases – Current Concepts and Potential Applications</p>

“…31 This may suggest that the highest enzymatic activity can be found in gastric mucosa. 20 AMCase is expressed by lung epithelial cells and macrophages. AMCase mRNA expression and the number of AMCase-positive cells are upregulated during Th2 inflammation.…”

“…Higher AMCase enzyme and mRNA levels were found in omnivores (eg, pigs, chickens, monkeys) than in herbivores (eg, bovines) and carnivores (eg, dogs). 19,20 The highest levels of chitinase expression were reported in the lungs, stomach, kidney, and liver. 19,20 It may be hypothesized that a higher exposure to chitin-containing organisms results in the overexpression of chitinase genes.…”

“…19,20 The highest levels of chitinase expression were reported in the lungs, stomach, kidney, and liver. 19,20 It may be hypothesized that a higher exposure to chitin-containing organisms results in the overexpression of chitinase genes. 21 It is worth to note, however, that chitinase genes are not always present in the genome (ie, according to the National Center for Biotechnology Information (NCBI) genome database, the CHIT1 gene is absent in the dog genome).…”

Crab-Eating Monkey Acidic Chitinase (CHIA) Efficiently Degrades Chitin and Chitosan under Acidic and High-Temperature Conditions

“…These primates feed on crabs and other chitin-containing organisms such as crustaceans and insects [41]. Previously, we performed a gene expression analysis and showed that the monkey expresses a high level of CHIA mRNA in the stomach [42]. Crab-eating monkey CHIA is 50 times more active than the human analogue [43].…”