Abstract
BackgroundRegnase-1 (MCPIP) has been identified as an anti-inflammatory agent, but little is known about its influence on liver ischemia/reperfusion (I/R) injury. Macrophages can evolve biphasic responses and differentiate into remarkable polarizations, contributing greatly to the uncontrolled inflammatory cascades during liver I/R injury. Therefore, the aim of this study was to explore whether regnase-1 participated in liver I/R via manipulating macrophage polarization.Materials and methodsC57BL/6 mice were randomly divided into five groups: Sham, I/R, Clodronate, Clo + BMDM, and Clo + LV MCPIP BMDM. A liver I/R model was established, and histopathological and immunostaining examinations were performed for the liver specimens; double immunofluorescence staining was used to localize MCPIP in the liver. Primary hepatocytes were isolated to simulate a hypoxia and reoxygenation (H/R) model in vitro. Bone marrow-derived macrophages (BMDM) were extracted and subjected to lentiviral transduction to knockdown MCPIP expression. BMDM with or without MCPIP deletion were exposed to H/R supernatants, and the polarized states were measured by flow cytometry. RT-PCR analysis and Western blot were also conducted.ResultsCompared to those in the Sham group, liver functions and Suzuki’s scores were deteriorated in the I/R group, which were reversed in the Clodronate group. The increased expression of regnase-1 in the I/R group diminished with pretreatment of clodronate liposomes. Subsequent double immunofluorescence staining established the localization of regnase-1 in macrophages in the liver. The insulted lesions in the Clodronate group became progressively aggravated with adoptive transfer of BMDM in the Clo + BMDM group, and they were further exacerbated with the transfusion of BMDM with MCPIP knockdown in the Clo + LV MCPIP BMDM group. Gene expressions of M1 and M2 markers were detected by RT-PCR, suggesting that MCPIP knockdown tended to favor the M1 transformation. Subsequently, ex vivo flow cytometrical detection showed that, upon stimulation by H/R supernatants, LV-MCPIP BMDM posed a higher ratio of M1/M2 than BMDM. Finally, we found that MCPIP participated in macrophage M1/M2 polarization through the NF-κB, C/EBPβ, and PPARγ signaling pathways during liver I/R.ConclusionOur study confirms that regnase-1 plays a critical role in liver I/R via regulation of macrophage polarization and, thus, might offer a potential therapeutic target.
Highlights
The pathogenesis of ischemia/reperfusion (I/R) involves an initial deprivation of blood supply and a subsequent restoration of perfusion, featuring an extensive inflammatory response and exacerbated tissue injury (Qiu et al, 2017; Wan et al, 2020)
Serum ALT and aspartate transaminase (AST) levels were detected to be profoundly increased 6 h after reperfusion in the I/R group compared with corresponding levels in the sham-operated group (Sham) group (Figures 1D,E)
We found that macrophages with MCPIP deletion by lentiviral transduction caused more striking impairments compared to macrophages themselves during liver I/R
Summary
The pathogenesis of ischemia/reperfusion (I/R) involves an initial deprivation of blood supply and a subsequent restoration of perfusion, featuring an extensive inflammatory response and exacerbated tissue injury (Qiu et al, 2017; Wan et al, 2020). Hepatic I/R injury is a very common condition during major liver surgeries, but the complex mechanisms remain enigmatic. It is an acute and dynamic process, throughout which the innate and adaptive immune systems experience unprecedented irritations, persistently driving the ensuing amplified cascades downstream. Kupffer cells (KCs), the liver-resident macrophages, which are representative of the largest fixed population of macrophages for the host, are dedicated to the maintenance of liver homeostasis. They are essentially engaged in the innate immune responses during hepatic I/R. The aim of this study was to explore whether regnase-1 participated in liver I/R via manipulating macrophage polarization
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
