Quantitative Real-Time PCR Analysis of YKL-40 and Its Comparison with Mammalian Chitinase mRNAs in Normal Human Tissues Using a Single Standard DNA

Abstract

YKL-40 (YKL for the first three N-terminal residues of a 40 kDa protein) belongs to a group of human chitinase-like proteins (CLPs), which are similar to chitinases but lack chitinolytic activity. YKL-40 mRNA and its protein levels have been reported elevated in multiple disorders including asthma, cystic fibrosis, rheumatoid arthritis and malignant tumors. Here, we quantified the YKL-40 mRNA levels and compared them with chitinases and housekeeping genes in normal human tissues. To establish the quantitative real-time PCR (qPCR) system for evaluation of relative YKL-40 mRNA levels, we constructed a human standard DNA molecule by ligating cDNAs of YKL-40, two mammalian chitinases and two housekeeping genes in a one-to-one ratio. We generated cDNAs from various normal human tissues and analyzed the YKL-40 mRNA expression levels using a qPCR system with the standard DNA. We found that YKL-40 mRNA is present widely in human tissues while its expression patterns exhibit clear tissue specificity. Highest YKL-40 mRNA levels were detected in the liver, followed by kidney, trachea and lung. The levels of YKL-40 mRNA in the kidney and liver were more than 100-times higher than those of chitotriosidase mRNA. Our study provides for the first time a comprehensive analysis of the relative expression levels of YKL-40 mRNA versus mammalian chitinases in normal human tissues.

Changes in serum chitinase 3‐like 1 levels correlate with changes in liver fibrosis measured by two established quantitative methods in chronic hepatitis B patients following antiviral therapy

“…Also known as YKL‐40, CHI3L1 belongs to the chitinase family but lacks chitinolytic activity, which highly enriches in the liver . It was reported to act as a growth factor for fibroblasts and to be involved in matrix remodeling .…”

“…Also known as YKL-40, CHI3L1 belongs to the chitinase family but lacks chitinolytic activity, which highly enriches in the liver. 8,9 It was reported to act as a growth factor for fibroblasts and to be involved in matrix remodeling. 10,11 Serum CHI3L1 levels were reported to be associated with the severity of liver fibrosis caused by non-alcoholic fatty liver disease, schistosomiasis, hepatitis C virus, and HBV.…”

The clinical significance of serum chitinase 3‐like 1 in hepatitis B–related chronic liver diseases

“…Chitinase 3‐like 1 (CHI3L1) is a member of the chitinase family, which can combine with chitin but lacks chitinolytic activity . CHI3L1 makes a difference in the process of inflammation and tissue remodeling Recently, CHI3L1 mRNA expression was characterized by tissue specificity, which level was highest in the liver . Johansen et al reported that the expression level of CHI3L1 in serum could evaluate the degree of liver fibrosis.…”

Chitinase-3-like 1 is a biomarker of acute kidney injury and mortality in paediatric severe malaria

“…Chitinase-3-like 1 protein (CHI3L1) is a 39 kDa secreted glycoprotein produced by a variety of cell types in response to inflammation, including activated macrophages, neutrophils, and fibroblasts. CHI3L1 is highly expressed in healthy kidney tissue [ 19 ] and is freely filtered by the glomerulus. CHI3L1 is also secreted by activated macrophages in the kidney upon stress or damage [ 20 ].…”