Degenerative Suspensory Ligament Desmitis (DSLD) in Peruvian Paso Horses Is Characterized by Altered Expression of TGFβ Signaling Components in Adipose-Derived Stromal Fibroblasts.

This study investigates Degenerative Suspensory Ligament Desmitis (DSLD), a disease in Peruvian Paso horses, and its connection to lowered expression of genes that are targeted by TGFβ signaling in the horse’s adipose-derived stromal fibroblasts. The aim is to create a disease risk test that can be used prior to breeding these horses.

Background

• Equine Degenerative Suspensory Ligament Desmitis (DSLD) is a debilitating illness found in Peruvian Paso horses. The disease typically appears when the horse is between 7-15 years old and is characterized by lameness, disorganization of collagen fibers, and chondroid deposition (the presence of cartilage-like material) in the ligament’s body.
• The purpose of the study was to develop a risk assessment test which could be used to examine horses’ risk for DSLD prior to breeding.

Method

• Researchers quantified the expression of 76 genes that are targeted by TGFβ signaling in the animals’ adipose-derived stromal fibroblasts (ADSCs). ADSCs are a type of cell in the horse’s fat tissue.
• The study involved six DSLD-affected horses and five unaffected horses.

Key Findings

• A majority (35) of the observed genes had lower expression in cells from the DSLD-affected horses. This difference was largely eliminated by the addition of exogenous TGFβ1, a growth factor that controls a variety of cellular functions.
• The impact of TGFβ1 on gene expression was blocked by the inhibitor LY2109761, which demonstrated that the signaling was via a TGFβR1/2 complex.
• The pattern of genes affected suggests that the pathology of DSLD is tied to a general metabolic disturbance. The most significantly altered genes in DSLD-affected cells — ATF3, MAPK14, ACVRL1 (ALK1), SMAD6, FOS, CREBBP, NFKBIA, and TGFBR2 — control a variety of cellular metabolic responses.

Implications

• These findings provide potential biomarkers for developing a risk test for DSLD, which could allow for earlier intervention and potentially reduce the incidence of the disease by making informed breeding decisions.
• The results also give some insight into the mechanisms of DSLD at the molecular level, enhancing our understanding of the disease and opening potential avenues of treatment.