Equine bone marrow-derived mesenchymal stromal cells inhibit reactive oxygen species production by neutrophils.

The research article discusses how horse bone marrow-derived mesenchymal stromal cells (MSCs) can reduce the amount of reactive oxygen species (ROS) produced by neutrophils, which are a type of white blood cell. This finding suggests that horse MSCs could be beneficial in cases of extreme or chronic inflammation where neutrophils are major contributors.

Study Background

• The research focuses on Polymorphonuclear neutrophils (PMN), a type of leukocyte present in the bloodstreams of most mammals, including horses. PMNs are crucial for defense against many infectious diseases.
• However, the same pathways that bolster PMN numbers to fight pathogens could also contribute to unchecked inflammation, causing harm to the body.
• Mesenchymal stem/stromal cells (MSCs) are a diverse group of cells notable for their anti-inflammatory properties. MSCs can interact with virtually every cell type in the immune system, including PMNs.
• This study aims to analyze how horse bone marrow-derived MSCs influence the processes of PMN phagocytosis (the engulfing and destruction of pathogens), ROS production (a byproduct of PMN action that can cause damage when overproduced), and NETs generation (neutrophil extracellular traps are a defense mechanism of PMNs).

Research Findings

• The research found that when PMNs were co-cultured with MSCs, they produced significantly less ROS than PMN cultured alone. Hence, the MSCs have a modulating effect, reducing the ROS production of PMNs.
• Notably, this change in behavior remained even after stimulation with Phorbol Myristate Acetate (PMA), proving that the MSCs conditioned the PMNs to produce fewer ROS consistently.
• Furthermore, it was discovered that exposing PMNs to the supernatant of MSCs significantly inhibited ROS production without impacting their phagocytic ability or NETosis capacity–their ability to form neutrophil extracellular traps to catch and kill microbes.

Implications of the Study

• The research indicates that horse bone marrow-derived MSCs can regulate the production of ROS by PMNs without negatively impacting their function. This implies that they may be able to maintain the essential defense capabilities of neutrophils while curbing their harmful overactivity.
• Given these results, MSCs could be a potential therapeutic treatment in excessive or chronic inflammation conditions where neutrophils are primarily responsible. This opens a new possibility for managing inflammation-related conditions in veterinary medicine.