Grant: DRA : Canada Graduate Research Scholarship - Doctoral Program (CGRS D)

Spinal cord injury (SCI) is a life-changing condition that affects over 86,000 Canadians, with almost 5,000 new cases annually. This injury often leads to paralysis at and below the site of injury, along with other complications including sexual dysfunction, loss of bladder control, and pain. After the initial damage, the body's immune system responds to clear tissue debris and initiate the repair response. While this process is important for healing, it can also cause additional "secondary" damage to healthy tissue, limiting recovery. Monocyte-derived macrophages (MDMs) are key immune cells involved in this response that drive much of the tissue damage. These circulating cells reside in reservoirs such as the bone, spleen, gut, and blood, before being recruited to the spinal cord. Previous work from other labs found that eliminating splenic MDMs did not alter recovery, so another source must be responsible for the destructive nature of these cells. We propose using a photoconvertible mouse to track MDMs across tissues. We will examine the contribution of cells across organs to tissue damage and inflammation. By selectively targeting the different sources of harmful cells, such as by splenectomy, genetic inhibition of circulating monocytes, or modulation of the gut immune environment with probiotics, we aim to determine the populations responsible for secondary tissue damage. Understanding and manipulating these key immune sources could provide new strategies to protect spinal cord tissue and improve functional recovery after SCI.