Androgens stimulate erythropoiesis through the DNA-binding activity of the androgen receptor in non-hematopoietic cells

Background: Androgens function through DNA and non-DNA binding-dependent signalling of the androgen receptor (AR). How androgens promote erythropoiesis is not fully understood. Design and methods: To identify the androgen signalling pathway, we treated male mice lacking the second zinc finger of the DNA-binding domain of the AR (AR^ΔZF2) with non-aromatizable 5α-dihydrotestosterone (5α-DHT) or aromatizable testosterone. To distinguish direct hematopoietic and non-hematopoietic mechanisms, we performed bone marrow reconstitution experiments. Results: In wild-type mice, 5α-DHT had greater erythroid activity than testosterone, which can be aromatized to estradiol. The erythroid response in wild-type mice following 5α-DHT treatment was associated with increased serum erythropoietin (EPO) and its downstream target erythroferrone, and hepcidin suppression. 5α-DHT had no erythroid activity in AR^ΔZF2 mice, proving the importance of DNA binding by the AR. Paradoxically, testosterone, but not 5α-DHT, suppressed EPO levels in AR^ΔZF2 mice, suggesting testosterone following aromatization may oppose the erythroid-stimulating effects of androgens. Female wild-type mice reconstituted with AR^ΔZF2 bone marrow cells remained responsive to 5α-DHT. In contrast, AR^ΔZF2 mice reconstituted with female wild-type bone marrow cells showed no response to 5α-DHT. Conclusion: Erythroid promoting effects of androgens are mediated through DNA binding-dependent actions of the AR in non-hematopoietic cells, including stimulating EPO expression.