Stroke-Homing Peptide-DNase1 Alleviates Intestinal Ischemia Reperfusion Injury by Selectively Degrading Neutrophil Extracellular Traps.

Neutrophil extracellular traps (NETs) act as a vital first line of defence against tissue damage and pathogens, playing a significant role in improving diseases such as intestinal ischemia reperfusion injury (IRI). However, we observed that after intestinal injury, intestinal bacteria and lipopolysaccharides (LPS) can enter the circulatory system, leading to a significant secondary increase in NETs production and the subsequent activation of a coagulation cascade. This phenomenon contributes to a pathological process known as the 'second strike' of NETs, which exaggerates intestinal damage and microcirculation disturbance. Selectively mitigating the detrimental effects associated with this second strike presents a promising therapeutic strategy. We developed an innovative conjugate of stroke-homing peptide (SHp) and DNase1 (SHp-DNase1) to enhance the stability of DNase in the bloodstream while selectively targeting NETs in thromboembolic events. The effects of SHp-DNase1 on blood flow, ischemia, and vascular leakage were evaluated in a mouse model using laser Doppler flowmetry and an in vivo imaging system. Levels of LPS and NETs were elevated in patients with IRI. Similarly, the expression of NETs and LPS was upregulated in mice with intestinal IRI. In vivo imaging revealed disturbances in intestinal microcirculation, accompanied by intestinal leakage, which were effectively reversed by the administration of SHp-DNase1. Almost all of the SHp-DNase1 localised to the gastrointestinal tract, demonstrating the effective targeting of DNase1 to the site of intestinal injury via SHp guidance. Furthermore, the combination of SHp-DNase1 and CRO significantly reduced the expression of ischemia-inducible factors, leading to a marked decrease in mortality in the mouse model. These findings suggest that intestinal LPS leakage correlated with NETs exacerbation plays a critical role in IRI. The combination of SHp-DNase1 and CRO is an effective treatment strategy by simultaneously controlling inflammation and addressing microcirculatory disorders induced by NETs in the therapy of IRI.