Overexpression of Brg1 Alleviates Hepatic Ischemia/Reperfusion-Induced Acute Lung Injury through Antioxidative Stress Effects

Impact of propofol versus desflurane anesthesia on postoperative hepatic and renal functions in infants with living-related liver transplantation: a randomized controlled trial

BACKGROUND

The effects of anesthetics on liver and kidney functions after infantile living-related liver transplantation (LRLT) are unclear. This study aimed to investigate the effects of propofol-based total intravenous anesthesia (TIVA) or desflurane-based inhalation anesthesia on postoperative liver and kidney functions in infant recipients after LRLT and to evaluate hepatic ischemia-reperfusion injury (HIRI).

METHODS

Seventy-six infants with congenital biliary atresia scheduled for LRLT were randomly divided into two anesthesia maintenance groups: group D with continuous inhalation of desflurane and group P with an infusion of propofol. The primary focus was to assess alterations of liver transaminase and serum creatinine (Scr) levels within the first 7 days after surgery. And the peak aminotransferase level within 72 h post-surgery was used as a surrogate marker for HIRI.

RESULTS

There were no differences in preoperative hepatic and renal functions between the two groups. Upon the intensive care unit (ICU) arrival, the levels of aspartate aminotransferase (AST, P = 0.001) and alanine aminotransferase (ALT, P = 0.005) in group P were significantly lower than those in group D. These changes persisted until the fourth and sixth days after surgery. The peak AST and ALT levels within 72 h after surgery were also lower in group P than in group D (856 (552, 1221) vs. 1468 (732, 1969) U/L, P = 0.001 (95% CI: 161-777) and 517 (428, 704) vs. 730 (541, 1100) U/L, P = 0.006, (95% CI: 58-366), respectively). Patients in group P had lower levels of Scr upon the ICU arrival and on the first day after surgery, compared to group D (17.8 (15.2, 22.0) vs. 23.0 (20.8, 30.8) μmol/L, P < 0.001 (95% CI: 3.0-8.7) and 17.1 (14.9, 21.0) vs. 20.5 (16.5, 25.3) μmol/L, P = 0.02 (95% CI: 0.0-5.0) respectively). Moreover, the incidence of severe acute kidney injury was significantly lower in group P compared to that in group D (15.8% vs. 39.5%, P = 0.038).

CONCLUSIONS

Propofol-based TIVA might improve liver and kidney functions after LRLT in infants and reduce the incidence of serious complications, which may be related to the reduction of HIRI. However, further biomarkers will be necessary to prove these associations.

Cardiovascular Disease and miRNAs: Possible Oxidative Stress-Regulating Roles of miRNAs

MicroRNAs (miRNAs) have been highlighted as key players in numerous diseases, and accumulating evidence indicates that pathological expressions of miRNAs contribute to both the development and progression of cardiovascular diseases (CVD), as well. Another important factor affecting the development and progression of CVD is reactive oxygen species (ROS), as well as the oxidative stress they may impose on the cells. Considering miRNAs are involved in virtually every biological process, it is not unreasonable to assume that miRNAs also play critical roles in the regulation of oxidative stress. This narrative review aims to provide mechanistic insights on possible oxidative stress-regulating roles of miRNAs in cardiovascular diseases based on differentially expressed miRNAs reported in various cardiovascular diseases and their empirically validated targets that have been implicated in the regulation of oxidative stress.

Single-cell analysis reveals the immune heterogeneity and interactions in lungs undergoing hepatic ischemia-reperfusion

Hepatic ischemia-reperfusion IR (HIR) is an unavoidable pathophysiological process during liver transplantation, resulting in systematic sterile inflammation and remote organ injury. Acute lung injury (ALI) is a serious complication after liver transplantation with high postoperative morbidity and mortality. However, the underlying mechanism is still unclear. To assess the phenotype and plasticity of various cell types in the lung tissue microenvironment after HIR at the single-cell level, single-cell RNA sequencing (scRNA-seq) was performed using the lungs from HIR-induced mice. In our results, we identified 23 cell types in the lungs after HIR and found that this highly complex ecosystem was formed by subpopulations of bone marrow-derived cells that signaled each other and mediated inflammatory responses in different states and different intervals. We described the unique transcriptional profiles of lung cell clusters and discovered two novel cell subtypes (Tspo+Endothelial cells and Vcan+ monocytes), as well as the endothelial cell-immune cell and immune cell-T cell clusters interactome. In addition, we found that S100 calcium binding protein (S100a8/a9), specifically and highly expressed in immune cell clusters of lung tissues and exhibited detrimental effects. Finally, the cellular landscape of the lung tissues after HIR was established, highlighting the heterogeneity and cellular interactions between major immune cells in HIR-induced lungs. Our findings provided new insights into the mechanisms of HIR-induced ALI and offered potential therapeutic target to prevent ALI after liver transplantation.

Role and mechanism of ferroptosis in acute lung injury

Ferroptosis is a new non-apoptotic cell death caused by the accumulation of dysregulated metabolism of ferric iron, amino acids or lipid peroxidation. Increasing studies suggest that ferroptosis is involved in the acute lung injury (ALI). This article aims to review the role of ferroptosis in ALI. ALI is a common respiratory disease and presents a high mortality rate. Inhibiting cell ferroptosis of lung improves the ALI. In addition, several signaling pathways are related to ferroptosis in ALI, involving in iron homeostasis, lipid peroxidation, and amino acid metabolism. Moreover, there are various key factors to regulate the occurrence of ferroptosis in ALI, such as ACSL4, NRF2, and P53. The ACSL4 promotes the ferroptosis, while the NRF2 alleviates the ferroptosis in ALI. The main effect of P53 is to promote ferroptosis. Accordingly, ferroptosis is involved in ALI and may be an important therapeutic target for ALI.

MicroRNA-146a Improved Acute Lung Injury Induced by hepatic Ischemia-reperfusion Injury by Inhibiting PRDX1

Hepatic ischemia-reperfusion injury (HIRI)-induced acute lung injury (ALI) is characterized by high incidence and poor prognosis. The regulatory role of microRNA-146a (miR-146a) in HIRI has been reported, but if miR-146a could affect the progression of HIRI-induced ALI has not been reported. The mice HIRI model was established by ligating left hepatic portal vein and hepatic artery for 60 minutes and then treating with reperfusion for 4 hours. Hypoxia-reoxygenation (HR) was performed to establish cell model. The binding site between miR-146a and Peroxidase 1 (PRDX1) was predicted and validated. The levels of inflammation factors and redox markers were detected with commercial kits. Significant lower expression of miR-146a and higher expression of PRDX1 in HIRI animal model were observed. miR-146a inhibited the liver injury after HIRI induction through targeting PRDX1. miR-146a inhibited the lung injury caused by HIRI via regulating PRDX1. The inhibition of cell apoptosis and inflammation factors by miR-146a were reversed by pcDNA-PRDX1. This research demonstrated that miR-146a improved ALI caused by HIRI by inhibiting apoptosis, inflammation, oxidative condition through targeting PRDX1. This study might provide a novel thought for the prevention and treatment of ALI caused by HIRI by regulating miR-146a/PRDX1 axis.

Buyang Huanwu decoction alleviates oxidative injury of cerebral ischemia-reperfusion through PKCε/Nrf2 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ischemic stroke is a significant risk factor for human health, and Buyang Huanwu Decoction is a classical and famous Chinese formula for treating it, but without clear pharmacological mechanism.

AIM OF THE STUDY

The aim of this study was to investigate that the molecular mechanism of BYHWD activation of the PKCε/Nrf2 signaling pathway to attenuate cerebral ischemia-reperfusion (I/R) oxidative damage.

MATERIALS AND METHODS

The MCAO method was used to establish a brain I/R injury model in SD rats, and neurological deficits were evaluated by neurological function score. Neuronal damage was observed by Nissl staining and immunofluorescence detection of MAP2 expression. Oxidative damage was observed by ROS, SOD, GSH-PX, MDA, and 8-OHdG. Changes in mitochondrial membrane potential were detected by using the fluorescent probe JC-1. The Western blot analysis detected protein expression of PKCε, P-PKCε, total Nrf2, nuclear Nrf2, HO-1, and NQO1.

RESULTS

BYHWD significantly enhanced neural function, reduced neuronal damage, inhibited the production of ROS, decreased MDA and 8-OHdG levels, increased SOD and GSH-PX activity to reduce oxidative damage, and restored mitochondrial membrane potential. BYHWD and Nrf2 activator TBHQ increased total Nrf2, nucleus Nrf2 protein expression, and its downstream HO-1 and NQO1 proteins, and the administration of the Nrf2 inhibitor brusatol reduced the enhancing effect of BYHWD. Meanwhile, BYHWD increased the expression of PKCε and P-PKCε and the administration of the PKCε inhibitor εV1-2 reduced the effect of BYHWD in increasing the expression of PKCε, P-PKCε, nuclear Nrf2, and HO-1, as well as promoting the effect of Nrf2 translocation to the nucleus.

CONCLUSION

This study marks the first to demonstrate that BYHWD ameliorates oxidative damage and attenuates brain I/R injury by activating the PKCε/Nrf2/HO-1 pathway.

Risk factors for pulmonary complications after laparoscopic liver resection: a multicenter retrospective analysis

BACKGROUND

Postoperative pulmonary complications (PPCs) are among the most common complications after liver resection. Although the application of laparoscopy has reduced the incidence of PPCs, the rate of PPCs after laparoscopic liver resection (LLR) remains high and the risk factors for the same are unclear. Therefore, this study aimed to determine the risk factors for PPCs after LLR.

METHODS

In this multicenter study, 296 patients underwent LLR from January 2019 to December 2020. Demographic data, pathological variables, and perioperative variables were reviewed. Univariate and multivariate analyses were performed to identify the independent risk factors for PPCs.

RESULTS

Of the 296 patients, 80 (27.0%) developed PPCs. Patients with PPCs had significantly increased total costs, operation costs, length of stays, and postoperative hospital stays. Multivariate analysis identified three independent risk factors for PPCs after LLR: smoking [Odds ratio (OR): 5.413, 95% confidence intervals (CI): 2.446-11.978, P =  < 0.001], location of lesion in segment 7 or 8 (OR 3.134, 95% CI 1.593-6.166, P = 0.001), duration of liver ischemia (OR 1.038, 95% CI 1.022-1.054, P < 0.001), and presence of intraoperative hypothermia (OR 3.134, 95% CI 1.593-6.166, P < 0.001).

CONCLUSION

Smoking, location of lesion in segment 7 or 8, duration of liver ischemia and intraoperative hypothermia were independent risk factors for PPCs which significantly increased the length of stays and burden of healthcare costs.

Effect of silibinin on the expression of MMP2, MMP3, MMP9 and TIMP2 in kidney and lung after hepatic ischemia/reperfusion injury in an experimental rat model

PURPOSE

The protective effect of silibinin on kidney and lung parenchyma during hepatic ischemia/reperfusion injury (IRI) is explored.

METHODS

Sixty-three Wistar rats were separated into three groups: sham; control (45 min IRI); and silibinin (200 μL silibinin administration after 45 min of ischemia and before reperfusion). Immunohistochemistry and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) were used to evaluate the expression levels of MMP2, MMP3, MMP9, and TIMP2 on kidney and lung.

RESULTS

Comparing sham vs. control groups, confirmed that hepatic IRI increased both renal and lung MMP2, MMP3, MMP9 and TIMP2 expressions starting at 180 min (p<0.001). Comparison of the control vs. silibinin groups showed a statistically significant decrease in the expression levels of MMP2, MMP3, and MMP9 and increase of TIMP2 in kidney and lung parenchyma. The starting point of this decrease was at 120 min after reperfusion, both for kidney and lung parameters, and it was statistically significant at 240 min (p<0.001) for kidney, while silibinin showed a peak of lung protection at 180 min after hepatic reperfusion (p<0.001).

CONCLUSIONS

Hepatic IRI causes distant kidney and lung damage, while a statistically significant protective action, both on kidney and lung parenchyma, is conveyed by the intravenous administration of silibinin.

Activation of vagovagal reflex prevents hepatic ischaemia-reperfusion-induced lung injury via anti-inflammatory and antioxidant effects

NEW FINDINGS

What is the central question of this study? Does vagus nerve stimulation have protective effects against both direct liver damage and distant lung injury in a rat model of hepatic ischaemia-reperfusion? What is the main finding and its importance? Vagus nerve stimulation provides protection through anti-inflammatory and anti-oxidative stress effects, possibly achieved by the vagovagal reflex.

ABSTRACT

Hepatic ischaemia-reperfusion (I/R) is not an isolated event; instead, it can result in remote organ dysfunction. The aim of this study was to investigate whether vagus nerve stimulation (VNS) can alleviate hepatic I/R-induced lung injury and to explore the underlying mechanism. Thirty male Sprague-Dawley rats were randomly allocated into five groups (n = 6 each): the sham group (without I/R or VNS), the I/R group (hepatic I/R) and three different VNS treatment groups (hepatic I/R plus VNS). The hepatic I/R group was subjected to occlusion of the portal vein and hepatic artery for 1 h, followed by 6 h of reperfusion. The intact afferent and efferent cervical vagus nerves were stimulated throughout the I/R process. During VNS, cervical neural activity was recorded. At the end of the experiment, liver function, the wet-to-dry lung weight ratio, histology of the liver and lung and inflammatory/oxidative indices were evaluated. We found that VNS significantly mitigated lung injury, as demonstrated by alleviation of pulmonary oedema and pathological alterations, by limiting inflammatory cytokine infiltration and increasing antioxidant capability. This proof-of-concept study suggested that VNS might protect patients from lung injury induced by hepatic I/R related to various circumstances.

The Role of Mitochondria in Liver Ischemia-Reperfusion Injury: From Aspects of Mitochondrial Oxidative Stress, Mitochondrial Fission, Mitochondrial Membrane Permeable Transport Pore Formation, Mitophagy, and Mitochondria-Related Protective Measures

Ischemia-reperfusion injury (IRI) has indeed been shown as a main complication of hepatectomy, liver transplantation, trauma, and hypovolemic shock. A large number of studies have confirmed that microvascular and parenchymal damage is mainly caused by reactive oxygen species (ROS), which is considered to be a major risk factor for IRI. Under normal conditions, ROS as a kind of by-product of cellular metabolism can be controlled at normal levels. However, when IRI occurs, mitochondrial oxidative phosphorylation is inhibited. In addition, oxidative respiratory chain damage leads to massive consumption of adenosine triphosphate (ATP) and large amounts of ROS. Additionally, mitochondrial dysfunction is involved in various organs and tissues in IRI. On the one hand, excessive free radicals induce mitochondrial damage, for instance, mitochondrial structure, number, function, and energy metabolism. On the other hand, the disorder of mitochondrial fusion and fission results in further reduction of the number of mitochondria so that it is not enough to clear excessive ROS, and mitochondrial structure changes to form mitochondrial membrane permeable transport pores (mPTPs), which leads to cell necrosis and apoptosis, organ failure, and metabolic dysfunction, increasing morbidity and mortality. According to the formation mechanism of IRI, various substances have been discovered or synthesized for specific targets and cell signaling pathways to inhibit or slow the damage of liver IRI to the body. Here, based on the development of this field, this review describes the role of mitochondria in liver IRI, from aspects of mitochondrial oxidative stress, mitochondrial fusion and fission, mPTP formation, and corresponding protective measures. Therefore, it may provide references for future clinical treatment and research.

Isorhapontigenin ameliorates cerebral ischemia/reperfusion injury via modulating Kinase Cε/Nrf2/HO-1 signaling pathway

BACKGROUND

Isorhapontigenin (ISO) has been shown to have antioxidant activity. This study aimed to investigate the antioxidant effects of ISO on cerebral ischemia/reperfusion (I/R) injury and its possible molecular mechanisms.

METHODS

Focal cerebral ischemia-reperfusion injury (MCAO/R) model and primary cortical neurons were established an oxygen-glucose deprivation (OGD / R) injury model. After 24 hr of reperfusion, the neurological deficits of the rats were analyzed and HE staining was performed, and the infarct volume was calculated by TTC staining. In addition, the reactive oxygen species (ROS) in rat brain tissue, the content of 4-Hydroxynonenal (4-HNE), and 8-hydroxy2deoxyguanosine (8-OHdG) were detected. Neuronal cell viability was determined by MTT assay. Western blot analysis was determined for protein expression.

RESULTS

ISO treatment significantly improved neurological scores, reduced infarct volume, necrotic neurons, ROS production, 4-HNE, and 8-OHdG levels. At the same time, ISO significantly increased the expression of Nrf2 and HO-1. The neuroprotective effects of ISO can be eliminated by knocking down Nrf2 and HO-1. In addition, knockdown of the PKCε blocked ISO-induced nuclear Nfr2, HO-1 expression.

CONCLUSION

ISO protected against oxidative damage induced by brain I/R, and its neuroprotective mechanism may be related to the PKCε/Nrf2/HO-1 pathway.

BRG1 Links TLR4 Trans-Activation to LPS-Induced SREBP1a Expression and Liver Injury

Multiple organ failure is one of the most severe consequences in patients with septic shock. Liver injury is frequently observed during this pathophysiological process. In the present study we investigated the contribution of Brahma related gene 1 (BRG1), a chromatin remodeling protein, to septic shock induced liver injury. When wild type (WT) and liver conditional BRG1 knockout (LKO) mice were injected with lipopolysaccharide (LPS), liver injury was appreciably attenuated in the LKO mice compared to the WT mice as evidenced by plasma ALT/AST levels, hepatic inflammation and apoptosis. Of interest, there was a down-regulation of sterol response element binding protein 1a (SREBP1a), known to promote liver injury, in the LKO livers compared to the WT livers. BRG1 did not directly bind to the SREBP1a promoter. Instead, BRG1 was recruited to the toll-like receptor 4 (TLR4) promoter and activated TLR4 transcription. Ectopic TLR4 restored SREBP1a expression in BRG1-null hepatocytes. Congruently, adenovirus carrying TLR4 or SREBP1a expression vector normalized liver injury in BRG1 LKO mice injected with LPS. Finally, a positive correlation between BRG1 and TLR4 expression was detected in human liver biopsy specimens. In conclusion, our data demonstrate that a BRG1-TLR4-SREBP1a axis that mediates LPS-induced liver injury in mice.

Alleviation of remote lung injury following liver ischemia/reperfusion: Possible protective role of vildagliptin

Lung injury is a serious condition encountered following hepatic ischemia/reperfusion (IR). This study aimed to explore whether a dipeptidyl peptidase-4 inhibitor agent vildagliptin (V) could alleviate the lung injury caused by hepatic IR in a rat model and if so elucidate its molecular protective mechanism. Three groups of rats were used. Sham group: received normal saline and exposed to a sham operation, IR group: received normal saline and subjected to the operation of hepatic I (45 min)/ R (180 min), V+IR group: received for 10 days intraperitoneal injection of V (10 mg/kg/day). After reperfusion, liver and lung were collected for biochemical and histological evaluation. Hepatic IR exhibited significant elevation in serum alanine aminotransferase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) enzyme levels, serum and lung malondialdehyde (MDA) and tumor necrosis factor-alpha (TNF-α) in addition to lung nitric oxide (NO) levels, hypoxia-inducible factor 1-alpha (HIF-1α) mRNA and protein levels, hepatocyte growth factor (HGF) mRNA expression, and inducible nitric oxide synthase (iNOS) mRNA and protein expressions in lung tissue along with a marked reduction in the serum and lung content of catalase in comparison to the sham group. Moreover, liver and lung injury in the IR group was detected by histopathological examination. Vildagliptin ameliorated markedly the biochemical changes as well as liver and lung architecture in comparison to the IR group. Vildagliptin mitigated the induced lung injury by hepatic IR via suppression of oxidative stress markers, pro-inflammatory cytokine TNF-α as well as the HIF1-α/iNOS/HGF expressions in lung tissue.

Activation of Akt-dependent Nrf2/ARE pathway by restoration of Brg-1 remits high glucose-induced oxidative stress and ECM accumulation in podocytes

Brahma-related gene 1 (Brg-1) is perceived as a cytoprotective protein due to its role in alleviating oxidative stress and apoptosis. Our study aimed to explore the role and mechanism of Brg-1 in high glucose (HG)-stimulated podocytes. The HG exposure downregulated Brg-1 and inactivated the protein kinase B (Akt) pathway in podocytes. Restoration of Brg-1 inhibited HG-induced viability reduction of podocytes. The HG-induced increase of reactive oxygen species and malondialdehyde levels and decrease of superoxide dismutase activity in podocytes were reversed by the Brg-1 overexpression. The Brg-1 overexpression terminated the HG-induced production of fibronectin, collagen IV, transforming growth factor-β1, and connective tissue growth factor. In addition, the Brg-1 overexpression activated Akt-dependent nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling in HG-stimulated podocytes. However, inhibition of the Akt pathway or Nrf2 silencing counteracted the protective effects of Brg-1 in HG-stimulated podocytes. In conclusion, the Brg-1 overexpression suppressed HG-induced oxidative stress and extracellular matrix accumulation by activation of Akt-dependent Nrf2/ARE signaling in podocytes.

Stabilizing mast cells improves acute lung injury after orthotopic liver transplantation via promotion of apoptosis in polymorphonuclear neutrophils

Postoperative pulmonary complications including acute lung injury (ALI) and acute respiratory distress syndrome have contributed to mortality and morbidity of orthotopic liver transplantation (OLT) with unclear mechanisms. Mast cells (MCs) and polymorphonuclear neutrophils (PMNs) are the main inflammatory cells and participants in the process of ALI. The present study was designed to investigate the role of MCs and PMNs and their potential relation to ALI following OLT. Rat orthotopic autologous liver transplantation (OALT) model was designed to determine lung injury at different time points after liver reperfusion. We also evaluated the function of MCs and the effect of tumor necrosis factor-α (TNF-α) and tryptase on ALI and PMN apoptosis in rats subjected to OALT. Histological scores and inflammatory factor levels as well as PMN apoptosis were measured. Rats suffered from ALI after OALT, which was demonstrated by a collapse of the pulmonary architecture, pulmonary edema, and infiltration of inflammatory cells in alveolar and interstitial spaces, as well as increased levels of proinflammatory cytokines. ALI maximized at 8 h after OALT. However, PMN apoptosis lagged behind the pulmonary injury and maximized at 16 h after OALT, when the acute inflammation resolution initiated. MC stabilization, and tryptase and TNF-α inhibitors could significantly decrease the lung pathophysiologic scores accompanied by an increase in PMN apoptosis. ALI after OALT was associated with MC activation and PMN apoptosis. ALI progression might be affected by delayed PMN apoptosis, which was related to MC activation. Induction of PMN apoptosis might alleviate ALI after OALT.

Effects of Connexin 32-Mediated Lung Inflammation Resolution During Liver Ischemia Reperfusion

BACKGROUND

Hepatic ischemia reperfusion (HIR) leads to a lung inflammatory response and subsequent pulmonary barrier dysfunction. The gap junction communication protein connexin 32 (Cx32), which is widely expressed in the lungs, participates in intercellular signaling. This study determined whether the communication protein Cx32 could affect pulmonary inflammation caused by HIR.

METHODS

Mice were randomly allocated into four groups (n = 8/group): (i) Cx32+/+ sham group; (ii) Cx32+/+ HIR model group; (iii) Cx32-/- sham group; and (iv) Cx32-/- HIR model group. Twenty-four hours after surgery, lung tissues were collected for bright field microscopy, western blot (Cx32, JAK2, p-JAK2, STAT3, p-STAT3), and immunofluorescence (ZO-1, 8-OHDG) analyses. The collected bronchoalveolar fluid was tested for levels of interleukin-6 (IL-6), matrix metalloproteinase 12 (MMP-12), and antitrypsin (α1-AT). Lung mmu-miR-26a/b expression was detected using a PCR assay.

RESULTS

Increased expression of Cx32 mRNA and protein was noted in the lungs after HIR. Cx32 deletion significantly aggravated pulmonary function from acute lung injury induced by HIR. In addition, Cx32 deletion decreased the protein level of ZO-1 (pulmonary function) and increased the level of the oxidative stress marker 8-OHDG in the lungs. Moreover, in the Cx32-/- HIR model group, the levels of IL-6 and MMP-12 in bronchoalveolar lavage fluid were significantly increased leading to activation of the JAK2/STAT3 pathway, and decreased α1-AT levels. Furthermore, we found mmu-miR-26a/b was significantly downregulated in the Cx32-/- HIR model group.

CONCLUSION

HIR leads to acute lung inflammatory injury. Cx32 deletion aggravates hepatic-derived lung inflammation, partly through blocking the transferring of mmu-miR-26a/b and leading to IL-6-related JAK2/STAT3 pathway activation.

The Role of BRG1 in Antioxidant and Redox Signaling

Redox homeostasis is regulated by critical molecules that modulate antioxidant and redox signaling (ARS) within the cell. Imbalances among these molecules can lead to oxidative stress and damage to cell functions, causing a variety of diseases. Brahma-related gene 1 (BRG1), also known as SMARCA4, is the central ATPase catalytic subunit of the switch/sucrose nonfermentable (SWI/SNF) chromatin remodeling complex, which plays a core role in DNA replication, repair, recombination, and transcriptional regulation. Numerous recent studies show that BRG1 is involved in the regulation of various cellular processes associated with ARS. BRG1, as a major factor in chromatin remodeling, is essential for the repair of oxidative stress-induced DNA damage and the activation of antioxidant genes under oxidative stress. Consequently, a comprehensive understanding of the roles of BRG1 in redox homeostasis is crucial to understand the normal functioning as well as pathological mechanisms. In this review, we summarized and discussed the role of BRG1 in the regulation of ARS.

Nrf2 and the Nrf2-Interacting Network in Respiratory Inflammation and Diseases

Atmospheric pollutants and cigarette smoke influence the human respiratory system and induce airway inflammation, injury, and pathogenesis. Activation of the NF-E2-related factor 2 (Nrf2) transcription factor and downstream antioxidant response element (ARE)-mediated transcriptions play a central role in protecting respiratory cells against reactive oxidative species (ROS) that are induced by airway toxins and inflammation. Recent studies have revealed that Nrf2 can also target and activate many genes involved in developmental programs such as cell proliferation, cell differentiation, cell death, and metabolism. Nrf2 is closely regulated by the interaction with kelch-like ECH-associated protein 1 (Keap1), while also directly interacts with a number of other proteins, including inflammatory factors, transcription factors, autophagy mediators, kinases, epigenetic modifiers, etc. It is believed that the multiple target genes and the complicated interacting network of Nrf2 account for the roles of Nrf2 in physiologies and pathogeneses. This chapter summarizes the molecular functions and protein interactions of Nrf2, as well as the roles of Nrf2 and the Nrf2-interacting network in respiratory inflammation and diseases, including acute lung injury (ALI), asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis (PF), cystic fibrosis (CF), viral/bacterial infections, and lung cancers. Therapeutic applications that target Nrf2 and its interacting proteins in respiratory diseases are also reviewed.

Neutrophil Elastase Inhibitors Suppress Oxidative Stress in Lung during Liver Transplantation

Background

Neutrophil infiltration plays a critical role in the pathogenesis of acute lung injury following liver transplantation (LT). Neutrophil elastase is released from neutrophils during pulmonary polymorphonuclear neutrophil activation and sequestration. The aim of the study was to investigate whether the inhibition of neutrophil elastase could lead to the restoration of pulmonary function following LT.

Methods

In in vivo experiments, lung tissue and bronchoalveolar lavage fluid (BALF) were collected at 2, 4, 8, and 24 h after rats were subjected to orthotopic autologous LT (OALT), and neutrophil infiltration was detected. Next, neutrophil elastase inhibitors, sivelestat sodium hydrate (exogenous) and serpin family B member 1 (SERPINB1) (endogenous), were administered to rats before OALT, and neutrophil infiltration, pulmonary oxidative stress, and barrier function were measured at 8 h after OALT.

Results

Obvious neutrophil infiltration occurred from 2 h and peaked at 8 h in the lungs of rats after they were subjected to OALT, as evidenced by an increase in naphthol-positive cells, BALF neutrophil elastase activity, and lung myeloperoxidase activity. Treatment with neutrophil elastase inhibitors, either sivelestat sodium hydrate or SERPINB1, effectively reduced lung naphthol-positive cells and BALF inflammatory cell content, increased expression of lung HO-1 and tight junction proteins ZO-1 and occludin, and increased the activity of superoxide dismutase.

Conclusion

Neutrophil elastase inhibitors, sivelestat sodium hydrate and SERPINB1, both reduced lung neutrophil infiltration and pulmonary oxidative stress and finally restored pulmonary barrier function.

Propofol alleviates oxidative stress via upregulating lncRNA-TUG1/Brg1 pathway in hypoxia/reoxygenation hepatic cells

Reducing oxidative stress is an effective method to prevent hepatic ischaemia/reperfusion injury (HIRI). This study focuses on the role of propofol on the oxidative stress of hepatic cells and the involved lncRNA-TUG1/Brahma-related gene 1 (Brg1) pathway in HIRI mice. The mouse HIRI model was established and was intraperitoneally injected with propofol postconditioning. Hepatic injury indexes were used to evaluate HIRI. The oxidative stress was indicated by increasing 8-isoprostane concentration. Mouse hepatic cell line AML12 was treated with hypoxia and subsequent reoxygenation (H/R). The targeted regulation of lncRNA-TUG1 on Brg1 was proved by RNA pull-down, RIP (RNA-binding protein immunoprecipitation) and the expression level of Brg1 responds to silencing or overexpression of lncRNA-TUG1. Propofol alleviates HIRI and induces the upregulation of lncRNA-TUG1 in the mouse HIRI model. Propofol increases cell viability and lncRNA-TUG1 expression level in H/R-treated hepatic cells. In H/R plus propofol-treated hepatic cells, lncRNA-TUG1 silencing reduces cell viability and increased oxidative stress. LncRNA-TUG1 interacts with Brg1 protein and keeps its level via inhibiting its degradation. Brg1 overexpression reverses lncRNA-TUG1 induced the reduction of cell viability and the increase in oxidative stress. LncRNA-TUG1 silencing abrogates the protective role of propofol against HIRI in the mouse HIRI model. LncRNA-TUG1 has a targeted regulation of Brg1, and thereby affects the oxidative stress induced by HIRI. This pathway mediates the protective effect of propofol against HIRI of hepatic cell.

Phycocyanin/PEG-b-(PG-g-PEI) attenuated hepatic ischemia/reperfusion-induced pancreatic islet injury and enlarged islet functionality

Background

Hepatic ischemia/reperfusion-induced pancreatic islet injury (HI/RIPII) was an important pathophysiological phenomenon in clinics. In the present study, we observed the effects of phycocyanin on HI/RIPII. However, the half-life of phycocyanin was extremely short and limited its use in vivo.

Materials and methods

In order to overcome this shortcoming, poly(ethylene glycol)-b-(poly(l-glutamic acid)-g-polyethylenimine) (PEG-b-(PG-g-PEI)) was synthesized and estimated as a nanocarrier for lengthening delivery of phycocyanin through the abdominal subcutaneous injection in rats. Phycocyanin (isoelectric point=4.3) was encapsulated with PEG-b-(PG-g-PEI) via electrostatic interactions at pH 7.4.

Results

In vitro phycocyanin was fast and efficiently encapsulated and showing efficient loading and sustained release. In vivo the anti-HI/RIPII function of phycocyanin/PEG-b-(PG-g-PEI) complex was surveyed in rats using free phycocyanin as the controls, and the results showed that phycocyanin/PEG-b-(PG-g-PEI) complex reduced HI/RIPII property and enlarged islet functionality.

Conclusion

These results suggested that PEG-b-(PG-g-PEI) might be treated as a potential phycocyanin nanocarrier.

Dexmedetomidine Attenuates Orthotopic Liver Transplantation-Induced Acute Gut Injury via α 2-Adrenergic Receptor-Dependent Suppression of Oxidative Stress

Patients with orthotopic liver transplantation (OLT) frequently develop acute gut injury (AGI), and dexmedetomidine (Dex) has been reported to exert a protective effect against AGI. We investigated whether Dex protects against AGI through antioxidative stress effects by the Nrf2/HO-1 antioxidative signaling pathway. Rats were randomly allocated into a sham group and six orthotopic autologous liver transplantation (OALT) groups receiving different doses of Dex together with/without α ₂-adrenergic receptor (AR) blockers. Intestinal tissues were collected to visualize the barrier damage and to measure the indexes of oxidative stress. For in vitro studies, rat intestinal recess epithelial cells (IEC-6) underwent hypoxia/reoxygenation (H/R), and the protective role of Dex was evaluated after α _2A-AR siRNA silencing. OALT resulted in increased oxidative stress, significant intestinal injury, and barrier dysfunction. Dex attenuated OALT-induced oxidative stress and intestinal injury, which was abolished by the pretreatment with the nonspecific α _2A-AR siRNA blocker atipamezole and the specific α _2A-AR siRNA blocker BRL-44408, but not by the specific _2B/C-AR siRNA blocker ARC239. Silencing of α _2A-AR siRNA also attenuated the protective role of Dex on alleviating oxidative stress in IEC-6 cells subjected to H/R. Dex exerted its protective effects by activating Nrf2/HO-1 antioxidative signaling. Collectively, Dex attenuates OALT-induced AGI via α _2A-AR-dependent suppression of oxidative stress, which might be a novel potential therapeutic target for OALT-induced AGI.

The Nox1/Nox4 inhibitor attenuates acute lung injury induced by ischemia-reperfusion in mice

Lung ischemia and reperfusion injury (LIRI) were mediated by several processes including over-production of reactive oxygen species (ROS) and inflammatory activation. ROS generated by nicotinamide adenine dinucletide phosphate (NADPH) oxidase (Nox) may play a pivotal role in pathophysiological changes in a range of disease. However, it was poorly understood in LIRI. Thus, the purpose of our study was to explore whether GKT137831, as a special dual inhibitor of Nox1 and 4, could alleviate LIRI in mice model and explore the minimal dose. According to the protocol, this study was divided into two parts. The first part was to determine the minimal dose of Nox1/4 inhibitor in attenuating LIRI via histopathology and apoptosis analysis. Eighteen C57BL/6J male wild-type mice were randomly divided in to sham, 2.5Nox+sham, 5.0Nox+sham, IR, 2.5Nox+IR and 5.0Nox+IR groups. According to the different group, mice were pretreated with corresponding dose of Nox1/4 inhibitors or normal saline. After LIRI, the results showed 5.0mg/kg Nox1/4 inhibitor could be considered as the minimal dose to alleviate injury by decreasing of lung injury score and the number of TUNEL-positive cells. The second part was to further verify the benefit of 5.0mg/kg Nox1/4 inhibitor in lung protective effects. Thirty-seven C57BL/6J male wild-type mice were divided in to sham, IR and 5.0Nox+IR groups randomly. The results showed that expressions of inflammatory, autophagy cytokines were markedly elevated and PH value was declined after LIRI. However, 5.0 mg/kg Nox1/4 inhibitor significantly attenuated cytokine production as reflected by immunohistochemistry, western blotting and Q-PCR analysis. In conclusion, our findings suggested that 5.0mg/kg Nox1/4 inhibitor contributed to protect lung tissue damage after LIRI via the suppression of inflammatory and autophagy activation.

Connexin32 plays a crucial role in ROS-mediated endoplasmic reticulum stress apoptosis signaling pathway in ischemia reperfusion-induced acute kidney injury

BACKGROUND

Ischemia-reperfusion (I/R)-induced acute kidney injury (AKI) not only prolongs the length of hospital stay, but also seriously affects the patient's survival rate. Although our previous investigation has verified that reactive oxygen species (ROS) transferred through gap junction composed of connexin32 (Cx32) contributed to AKI, its underlying mechanisms were not fully understood and viable preventive or therapeutic regimens were still lacking. Among various mechanisms involved in organs I/R-induced injuries, endoplasmic reticulum stress (ERS)-related apoptosis is currently considered to be an important participant. Thus, in present study, we focused on the underlying mechanisms of I/R-induced AKI, and postulated that Cx32 mediated ROS/ERS/apoptosis signal pathway activation played an important part in I/R-induced AKI.

METHODS

We established renal I/R models with Cx32+/+ and Cx32-/- mice, which underwent double kidneys clamping and recanalization. ROS scavenger (N-acetylcysteine, NAC) and ERS inhibitors (4-phenyl butyric acid, 4-PBA, and tauroursodeoxycholic acid, TUDCA) were used to decrease the content of ROS and attenuate ERS activation, respectively.

RESULTS

Renal damage was progressively exacerbated in a time-dependent manner at the reperfusion stage, that was consistent with the alternation of ERS activation, including glucose regulated protein 78 (BiP/GRP78), X box-binding protein1, and C/EBP homologous protein expression. TUDCA or 4-PBA application attenuated I/R-induced ERS activation and protected against renal tubular epithelial cells apoptosis and renal damage. Cx32 deficiency decreased ROS generation and distribution between the neighboring cells, which attenuated I/R-induced ERS activation, and improved cell apoptosis and renal damage.

CONCLUSION

Cx32 mediated ROS/ERS/apoptosis signal pathway activation played an important part in I/R-induced AKI. Cx32 deficiency, ROS elimination, and ERS inhibition all could protect against I/R-induced AKI.

Suppression of microRNA-144-3p attenuates oxygen-glucose deprivation/reoxygenation-induced neuronal injury by promoting Brg1/Nrf2/ARE signaling

Accumulating evidence has reported that microRNA-144-3p (miR-144-3p) is highly related to oxidative stress and apoptosis. However, little is known regarding its role in cerebral ischemia/reperfusion-induced neuronal injury. Herein, our results showed that miR-144-3p expression was significantly downregulated in neurons following oxygen-glucose deprivation and reoxygenation (OGD/R) treatment. Overexpression of miR-144-3p markedly reduced cell viability, promoted cell apoptosis, and increased oxidative stress in neurons with OGD/R treatment, whereas downregulation of miR-144-3p protected neurons against OGD/R-induced injury. Brahma-related gene 1 (Brg1) was identified as a potential target gene of miR-144-3p. Moreover, downregulation of miR-144-3p promoted the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and increased antioxidant response element (ARE) activity. However, knockdown of Brg1 significantly abrogated the neuroprotective effects of miR-144-3p downregulation. Overall, our results suggest that miR-144-3p contributes to OGD/R-induced neuronal injury in vitro through negatively regulating Brg1/Nrf2/ARE signaling.