The present invention fulfills a need in the art for methods that promote hematopoietic and mesenchymal stem and lineage-specific cell proliferation and differentiation by growth in the presence of angiotensinogen, angiotensin I (AI), AI analogues, AI fragments and analogues thereof, angiotensin II (AII), AII analogues, AII fragments and analogues thereof and AII AT.sub.2 type 2 receptor agonists.