Grant's research is in the area of cardiovascular and chronic kidney disease with a specific focus on understanding the roles of oxidative stress, the immune system and the gut microbiome in promoting the vascular, cardiac and renal inflammation that contributes to these conditions. Grant's work has provided novel insights into the roles of NADPH oxidase-derived reactive oxygen species as signalling molecules under physiological conditions, and mediators of oxidative damage in vascular disease. His studies have also shed new light on the involvement of both innate (e.g. NLRP3 inflammasome, interleukin-18), and adaptive (B cells, autoantibodies) immune signalling pathways in the development of hypertension and kidney damage. More recently, Grant's team have been exploring the relationship between gut health and cardiovascular disease, with a particular focus on the gut virome. His work is funded by the National Health and Medical Research Council of Australia and the Heart Foundation of Australia.