YB-1 Recruits Drosha to Promote Splicing of pri-miR-192 to Mediate the Proangiogenic Effects of H2S

Aims: The genes targeted by miRNAs have been well studied. However, little is known about the feedback mechanisms to control the biosynthesis of miRNAs that are essential for the miRNA feedback networks in the cells. In this present study, we aimed at examining how hydrogen sulfide (H₂S) promotes angiogenesis by regulating miR-192 biosynthesis. Results: H₂S promoted in vitro angiogenesis and angiogenesis in Matrigel plugs embedded in mice by upregulating miR-192. Knockdown of the H₂S-generating enzyme cystathionine γ-lyase (CSE) suppressed in vitro angiogenesis, and this suppression was rescued by exogenous H₂S donor NaHS. Plakophilin 4 (PKP4) served as a target gene of miR-192. H₂S up-regulated miR-192 via the VEGFR2/Akt pathway to promote the splicing of primary miR-192 (pri-miR-192), and it resulted in an increase in both the precursor- and mature forms of miR-192. H₂S translocated YB-1 into the nuclei to recruit Drosha to bind with pri-miR-192 and promoted its splicing. NaHS treatment promoted angiogenesis in the hindlimb ischemia mouse model and the skin-wound-healing model in diabetic mice, with upregulated miR-192 and downregulated PKP4 on NaHS treatment. In human atherosclerotic plaques, miR-192 levels were positively correlated with the plasma H₂S concentrations. Innovation and Conclusion: Our data reveal a role of YB-1 in recruiting Drosha to splice pri-miR-192 to mediate the proangiogenic effect of H₂S. CSE/H₂S/YB-1/Drosha/miR-192 is a potential therapeutic target pathway for treating diseases, including organ ischemia and diabetic complications. Antioxid. Redox Signal. 36, 760-783. The Clinical Trial Registration number is 2016-224.

Renal Transplant Artery Inflow Stenosis Treated with Femorofemoral Bypass

In this case report we describe a novel and successful revascularization approach in instances of allograft and distal limb ischemia after kidney transplantation. Stenosis proximal to transplant renal artery anastomoses is a complication leading to allograft dysfunction and/or loss. We present a femorofemoral bypass graft with ringed polytetrafluoroethylene (PTFE). In this occasion, revascularization was achieved by a backflow mechanism. The approach described achieved its goal of revascularizing the allograft as well as the distal extremity, with both short- and long-term successful outcomes. Benefits of this approach when compared with re-implantation or procedures directly involving the transplant renal artery include minimization of ischemic time, no need to repair the stenosis, anastomoses with vessels of greater diameter, no need to perfuse the kidney, no need to take down the renal artery anastomosis, no need to dissect the transplanted kidney, and no further lower extremity ischemia. This approach does not require any proximal temporary inflow occlusion (as seen with stent placement) or clamping of the arterial inflow to the kidney. This procedure was completed without having to infuse any preservation fluid into the kidney.

Immunothrombolytic monocyte-neutrophil axes dominate the single-cell landscape of human thrombosis and correlate with thrombus resolution

Thrombotic diseases remain the major cause of death and disability worldwide, and the contribution of inflammation is increasingly recognized. Thromboinflammation has been identified as a key pathomechanism, but an unsupervised map of immune-cell states, trajectories, and intercommunication at a single-cell level has been lacking. Here, we reveal innate leukocyte substates with prominent thrombolytic properties by employing single-cell omics measures on human stroke thrombi. Using in vivo and in vitro thrombosis models, we propose a pro-resolving monocyte-neutrophil axis, combining two properties: (1) NR4A1hi non-classical monocytes acquire a thrombolytic and neutrophil-chemoattractive phenotype, and (2) blood neutrophils are thereby continuously recruited to established thrombi through CXCL8-CXCR1 and CXCR2 and adopt a hypoxia-induced thrombus-resolving urokinase receptor (PLAUR)+ phenotype. This immunothrombolytic axis results in thrombus resolution. Together, with this immune landscape of thrombosis, we provide a valuable resource and introduce the concept of "immunothrombolysis" with broad mechanistic and translational implications at the crossroad of inflammation and thrombosis.