Abstract
Purpose :
The immune privilege provided by the blood-retinal barrier can be breached by invading immune cells in response to disease and trauma. However, this immune invasion remains poorly understood, and there is active debate regarding which cells may be harmful and which may be helpful during disease progression, in part because the response of both resident and invading populations can be highly heterogeneous. Advances in high-throughput single-cell sequencing techniques can now disambiguate the heterogeneity and provide an improved understanding of the immune response.
Methods :
We performed single-cell 3’ mRNA sequencing on FACS enriched CD45mid-highCD11b+ cells in the murine retina before and during degeneration in a light-inducible genetic model of photoreceptor cell death (Arr-/-; Chen et al., 1999 IOVS 40, 2978-82).
Results :
Several peripheral immune cell types appear within the degenerating retina, including classical and inflammatory monocytes and monocyte-derived macrophages. Additionally, these results show that the resident microglial population consists of multiple heterogeneous sub-populations during degeneration. Analysis of differentially expressed genes and Gene Ontology biological process enrichment revealed that two of these populations, activated microglia and inflammatory macrophages, are mitotic; these Ki67+ activated macrophage-like cells can be identified in the retina using immunohistochemistry. This dataset can further be used to detect differences between sub-populations of immune cells and identify key signaling pathways driving the inflammatory response.
Conclusions :
Both infiltrating peripheral cells and proliferation of the resident and invading cells drive the dramatic inflammatory immune response during photoreceptor cell death. Single-cell sequencing is a highly effective technique for teasing apart the complex immune response that occurs during disease progression.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.