Homogenized mouse neural retina extracts stimulate an immune response in the mouse monocyte RAW 264.7 cell line

Abstract

There are two main protein products of the Basigin gene. One protein, known as Basiginvariant‐1 is expressed in the neural retina, specifically by the photoreceptor neurons. The other protein, known as Basigin‐variant‐2 is expressed throughout the body, including monocytes, as well as Müller glial cells and the retinal pigmented epithelium of the eye. Studies by this laboratory using recombinant proteins indicate that the two Basigin gene products interact via their extracellular domains and that the region of the Ig0 domain of Basigin‐variant‐1 used to interact with Basigin‐variant‐2 stimulates a proinflammatory response in monocytes. The purpose of the present study was to determine the biological relevance of this proinflammatory response using mouse neural retina samples rather than recombinantly‐generated proteins. It was hypothesized that mouse neural retina extracts would induce an immune response in mouse monocytes. Mouse neural retinas were obtained using an approved protocol and homogenized in phosphate buffered saline (PBS). The mouse neural retina extracts were then incubated with mouse monocytic RAW 264.7 cells. After 24 hours, the cell culture medium was collected and assayed for the expression of the pro‐inflammatory cytokine interleukin‐6 (IL‐6) via an ELISA and the cells were collected for RNA isolation and subsequent quantitative reverse transcription PCR (q‐RT‐PCR). Cells treated with a similar volume of PBS served as the controls. It was determined that incubation of the neural retina extracts with the RAW 264.7 cells elicits a proinflammatory response in the monocytes and that the expression of the innate immune molecule TLR4 significantly increases in expression in those cells, when compared to the response observed with PBS treatment. The data suggest a biological relevance for the observation that recombinant Basigin‐variant‐1 interacts with Basigin‐variant‐2 to stimulate a proinflammatory response in monocytes. This study is important for a better understanding of immune response aspects of diabetic retinopathy and other diseases in which the retinal pigmented epithelium is compromised and can allow the infiltration of monocytes into the neural retina.Support or Funding InformationUNF Office of Academic AffairsThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.