ZYZ-803, a novel hydrogen sulfide-nitric oxide conjugated donor, promotes angiogenesis via cross-talk between STAT3 and CaMKII

Endothelial angiogenesis plays a vital role in recovery from chronic ischemic injuries. ZYZ-803 is a hybrid donor of hydrogen sulfide (H₂S) and nitric oxide (NO). Previous studies showed that ZYZ-803 stimulated endothelial cell angiogenesis both in vitro and in vivo. In this study, we investigated whether the signal transducer and activator of transcription 3 (STAT3) and Ca²⁺/CaM-dependent protein kinase II (CaMKII) signaling was involved in ZYZ-803-induced angiogenesis. Treatment with ZYZ-803 (1 μM) significantly increased the phosphorylation of STAT3 (Tyr705) and CaMKII (Thr286) in human umbilical vein endothelial cells (HUVECs), these two effects had a similar time course. Pretreatment with WP1066 (STAT3 inhibitor) or KN93 (CAMKII inhibitor) blocked ZYZ-803-induced STAT3/CAMKII activation and significantly suppressed the proliferation and migration of HUVECs. In addition, pretreatment with the inhibitors significantly decreased ZYZ-803-induced tube formations along with the outgrowths of branch-like microvessels in aortic rings. In the mice with femoral artery ligation, administration of ZYZ-803 significantly increased the blood perfusion and vascular density in the hind limb, whereas co-administration of WP1066 or KN93 abrogated ZYZ-803-induced angiogenesis. By using STAT3 siRNA, we further explored the cross-talk between STAT3 and CaMKII in ZYZ-803-induced angiogenesis. We found that STAT3 knockdown suppressed ZYZ-803-induced HUVEC angiogenesis and affected CaMKII expression. ZYZ-803 treatment markedly enhanced the interaction between CaMKII and STAT3. ZYZ-803 treatment induced the nuclear translocation of STAT3. We demonstrated that both STAT3 and CaMKII functioned as positive regulators in ZYZ-803-induced endothelial angiogenesis and STAT3 was important in ZYZ-803-induced CaMKII activation, which highlights the beneficial role of ZYZ-803 in STAT3/CaMKII-related cardiovascular diseases.