C5AR1 and Hypertension: An animal model study [13] showed that hypertension induced by angiotensin II (Ang II) in a mouse model leads to an increase in the expression of complement component 3a receptor (C3aR) and complement component 5a receptor (C5aR) in forkhead box P3 (Foxp3) + regulatory cells (Tregs) (Table 1).