Cloning of equine type II procollagen and the modulation of its expression in cultured equine articular chondrocytes.

This research provides the complete nucleotide sequence of equine type II procollagen, a protein essential for the formation and health of horses’ cartilage, the expression of which has been found to be related to the age of the animal and can be reduced by particular cell signaling proteins.

Objective of the Research

• The main aim of this research is to discover the complete nucleotide sequence of equine (horse) type II procollagen mRNA. Type II procollagen is a vital protein in the formation and health of cartilage – the connective, supportive tissue in joints.
• This study also focuses on understanding the molecular characteristics of this equine specific-protein, factors that affect its expression, and its similarities with the human version of this protein.

Nucleotide Sequencing and Homology Comparison

• The researchers successfully isolated the mRNA for equine type II procollagen from horse articular chondrocytes (cartilage cells) and prepared a cDNA library to clone its sequence.
• The sequenced gene is 4257 bp (base pairs) long and showed high homology (similarity in genetic sequence) to the human version of the gene – 92.4% identical for the coding sequence and 97% identical for the propeptide, a part of the protein that often has regulatory functions.

Expression of Procollagen is Age-Linked

• The study also found that the level of expression of type II procollagen in horses is linked to the animal’s age when the chondrocytes are grown in cultures that maintain their natural phenotype (characteristics).

Impact of IL1-beta and TNF-alpha on Procollagen Expression

• The researchers also discovered that in cultures of young horse chondrocytes, the signaling proteins IL1-beta and TNF-alpha are capable of reducing the expression of type II procollagen mRNA in a dose-dependent manner.

Significance of the Study

• This study provides a milestone in genetic studies of horses, contributing a crucial equine gene’s complete sequence, essential for healthy joint and cartilage function.
• Moreover, understanding the factors that regulate the expression of this gene could lead to advances in managing disorders of cartilage in horses and potentially in humans given the high homology.
• The finding that the expression of type II procollagen in horses decreases in response to certain proteins could open new avenues for treating conditions where the production of collagen is compromised, such as osteoarthritis.