The Protective Effect of Magnesium Lithospermate B on Hepatic Ischemia/Reperfusion via Inhibiting the Jak2/Stat3 Signaling Pathway

Intraoperative Anesthetic Strategies to Mitigate Early Allograft Dysfunction After Orthotopic Liver Transplantation: A Narrative Review

Orthotopic liver transplantation (OLT) is the most effective treatment for patients with end-stage liver disease (ESLD). Hepatic insufficiency within a week of OLT, termed early allograft dysfunction (EAD), occurs in 20% to 25% of deceased donor OLT recipients and is associated with morbidity and mortality. Primary nonfunction (PNF), the most severe form of EAD, leads to death or retransplantation within 7 days. The etiology of EAD is multifactorial, including donor, recipient, and surgery-related factors, and largely driven by ischemia-reperfusion injury (IRI). IRI is an immunologic phenomenon characterized by dysregulation of cellular oxygen homeostasis and innate immune defenses in the allograft after temporary cessation (ischemia) and later restoration (reperfusion) of oxygen-rich blood flow. The rising global demand for OLT may lead to the use of marginal allografts, which are more susceptible to IRI, and thus lead to an increased incidence of EAD. It is thus imperative the anesthesiologist is knowledgeable about EAD, namely its pathophysiology and intraoperative strategies to mitigate its impact. Intraoperative strategies can be classified by 3 phases, specifically donor allograft procurement, storage, and recipient reperfusion. During procurement, the anesthesiologist can use pharmacologic preconditioning with volatile anesthetics, consider preharvest hyperoxemia, and attenuate the use of norepinephrine as able. The anesthesiologist can advocate for normothermic regional perfusion (NRP) and machine perfusion during allograft storage at their institution. During recipient reperfusion, the anesthesiologist can optimize oxygen exposure, consider adjunct anesthetics with antioxidant-like properties, and administer supplemental magnesium. Unfortunately, there is either mixed, little, or no data to support the routine use of many free radical scavengers. Given the sparse, limited, or at times conflicting evidence supporting some of these strategies, there are ample opportunities for more research to find intraoperative anesthetic strategies to mitigate the impact of EAD and improve postoperative outcomes in OLT recipients.

AhR-STAT3-HO-1/COX-2 signalling pathway may restrict ferroptosis and improve hMSC accumulation and efficacy in mouse liver

BACKGROUND AND PURPOSE

The low efficacy of mesenchymal stem cells (MSCs) has restricted their application in the treatment of liver disease. Emerging evidence suggested that ferroptosis may provoke hepatocyte dysfunction and exacerbate damage to the liver microenvironment. Here, we have investigated the contribution of liver ferroptosis to the elimination and effectiveness of human MSC (hMSC). Furthermore, potential links between liver ferroptosis and aryl hydrocarbon receptors (AhR) were explored.

EXPERIMENTAL APPROACH

Two mouse models, iron supplement-induced hepatic ferroptosis and hepatic ischaemia/reperfusion (I/R) injury, were used to identify effects of ferroptosis on hMSC pharmacokinetics (PK)/pharmacodynamics (PD).

KEY RESULTS

AhR inhibition attenuated hepatic ferroptosis and improved survival of hMSCs. hMSC viability was decreased by iron supplementation or serum from I/R mice. The AhR antagonist CH223191 reversed iron overload and oxidative stress induced by ferroptosis and increased hMSC concentration and efficacy in mouse models. Effects of CH223191 were greater than those of deferoxamine, a conventional ferroptosis inhibitor. Transcriptomic results suggested that the AhR-signal transducer and activator of transcription 3 (STAT3)-haem oxygenase 1/COX-2 signalling pathway is critical to this process. These results were confirmed in a mouse model of hepatic I/R injury. In mice pre-treated with CH223191, hMSC exhibited more potent protective effects, linked to decreased hepatic ferroptosis.

CONCLUSION AND IMPLICATIONS

Our findings showed that ferroptosis was a critical factor in determining the fate of hMSCs. Inhibition of AhR decreased hepatic ferroptosis, thereby increasing survival and therapeutic effects of hMSCs in mouse models of liver disease.

Molecular characterization and function of JAK/STAT pathway in IPEC-J2 cells during Clostridium perfringens beta2 toxin stimulation

Intestinal infection with C. perfringens is responsible for outbreaks of diarrhea in piglets. Janus kinase / signal transducer and activator of transcription (JAK/STAT) is a vital signaling pathway that regulates cellular activity and inflammatory response, closely correlated with multiple diseases development and advances. Currently, the potential effect of JAK/STAT on C. perfringens beta2 (CPB2) treatment on porcine intestinal epithelial (IPEC-J2) cells has not been explored. The expression of JAK/STAT genes or proteins in IPEC-J2 cells induced by CPB2 were observed by qRT-PCR and Western blot, and further used WP1066 to explore the effect of JAK2/STAT3 on mechanism employed by CPB2 on apoptosis, cytotoxicity, oxidative stress and inflammatory cytokines of IPEC-J2 cells. JAK2, JAK3, STAT1, STAT3, STAT5A and STAT6 were highly expressed in CPB2-induced IPEC-J2 cells, among which STAT3 had the highest expression. Moreover, apoptosis, cytotoxicity and oxidative stress were attenuated via blocking the activation of JAK2/STAT3 by using WP1066 in CPB2-treated IPEC-J2 cells. Furthermore, WP1066 significantly suppressed the secretion of interleukin (IL)-6, IL-1β and TNF-α induced by CPB2 in IPEC-J2 cells.Our findings provide some insights into the functional roles of JAK2/STAT3 in piglets against to C. perfringens infection.

The research development of STAT3 in hepatic ischemia-reperfusion injury

Ischemia-reperfusion injury (IRI) is a common complication of surgery, which can cause rapid deterioration of the liver function, increase the risk of graft rejection, and seriously affect the prognosis of patients. The signal transducer and activator of transcription 3 (STAT3) protein has been implicated in pathogenesis of IRI. STAT3 influences the mitochondria through multiple pathways and is also involved in apoptosis and other forms of programmed cell death. STAT3 is associated with Janus kinase (JAK), phosphoinositide-3 kinase (PI3K), and heme oxygenase-1 (HO-1) in liver IRI. The STAT3 pathway plays a dual role in IRI as it can also regulate lipid metabolism which may have potential for treating IRI fatty liver. In this review, we summarize research on the function of STAT3 in liver IRI to provide references for its application in the clinic.

Inhibition of the JAK2/STAT3 pathway and cell cycle re-entry contribute to the protective effect of remote ischemic pre-conditioning of rat hindlimbs on cerebral ischemia/reperfusion injury

AIMS

Remote ischemic pre-conditioning (RIPC) protects against ischemia/reperfusion (I/R) injury. However, the mechanisms underlying this protection remain unclear. In the present study, we investigated the role of Janus-activated kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway and cell cycle arrest, and their relationship with neuronal apoptosis following RIPC.

METHODS

A rat cerebral I/R injury model was induced by middle cerebral artery occlusion (MCAO), and AG490 was used to investigate the mechanisms of RIPC. p-JAK2-, p-STAT3-, cyclin D1-, and cyclin-dependent kinase 6 (CDK6) expression was assessed by Western blotting and immunofluorescence staining.

RESULTS

RIPC reduced the infarct volume, improved neurological function, and increased neuronal survival. Furthermore, p-JAK2 and p-STAT3 were detected during the initial phase of reperfusion; the expression levels were significantly increased at 3 and 24 h after reperfusion and were suppressed by RIPC. Additionally, the MCAO-induced upregulation of the cell cycle regulators cyclin D1 and CDK6 was ameliorated by RIPC. Meanwhile, cyclin D1 and CDK6 were colocalized with p-STAT3 in the ischemic brain.

CONCLUSION

RIPC ameliorates the induction of the JAK2/STAT3 pathway and cell cycle regulators cyclin D1 and CDK6 by MCAO, and this net inhibition of cell cycle re-entry by RIPC is associated with downregulation of STAT3 phosphorylation.

Regulatory Effect of JAK2/STAT3 on the Immune Function of Endotoxin-tolerant Dendritic Cells and its Involvement in Acute Liver Failure

BACKGROUND AND AIMS

Acute liver failure (ALF) is a potentially fatal clinical syndrome with no effective treatment. This study aimed to explore the role of Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway in modulating the phenotype and immune function of endotoxin-tolerant dendritic cells (ETDCs). In addition, we explored the use of EDTCs in an experimental model of ALF and investigated the associated mechanisms.

METHODS

In the in vitro experiment, ETDCs were transfected with adenovirus to induce SOCS1^+/+ETDCs and SOCS1^-/-ETDCs. Thereafter, costimulatory molecules and mixed lymphocyte reaction were assessed. Experimental mice were randomly divided into normal control, ALF, ALF+mock-ETDCs, ALF+SOCS1^+/+ETDCs, ALF+AG490, and ALF+AG490+SOCS1^+/+ETDCs groups. We examined the therapeutic effect of adoptive cellular immunotherapy by tail-vein injection of target ETDCs 12 h before ALF modeling. AG490, a JAK2/STAT3 inhibitor, was used in the in vivo experiment to further explore the protective mechanism of SOCS1^+/+ETDCs.

RESULTS

Compared with control ETDCs, SOCS1^+/+ETDCs had lower expression of costimulatory molecules, weaker allostimulatory ability, lower levels of IL-6 and TNF-α expression and higher IL-10 secretion. SOCS1^-/-ETDCs showed the opposite results. In the in vivo experiments, the ALF+SOCS1^+/+ETDCs and ALF+AG490+SOCS1^+/+ETDCs groups showed less pathological damage and suppressed activation of JAK2/STAT3 pathway. The changes were more pronounced in the ALF+AG490+SOCS1^+/+ETDCs group. Infusion of SOCS1^+/+ETDCs had a protective effect against ALF possibly via inhibition of JAK2 and STAT3 phosphorylation.

CONCLUSIONS

The SOCS1 gene had an important role in induction of endotoxin tolerance. SOCS1^+/+ETDCs alleviated lipopolysaccharide/D-galactosamine-induced ALF by downregulating the JAK2/STAT3 signaling pathway.

Ac2-26 attenuates hepatic ischemia-reperfusion injury in mice via regulating IL-22/IL-22R1/STAT3 signaling

Hepatic ischemia-reperfusion injury (HIRI) is one of the major sources of mortality and morbidity associated with hepatic surgery. Ac2-26, a short peptide of Annexin A1 protein, has been proved to have a protective effect against IRI. However, whether it exerts a protective effect on HIRI has not been reported. The HIRI mice model and the oxidative damage model of H₂O₂-induced AML12 cells were established to investigate whether Ac2-26 could alleviate HIRI by regulating the activation of IL-22/IL-22R1/STAT3 signaling. The protective effect of Ac2-26 was measured by various biochemical parameters related to liver function, apoptosis, inflammatory reaction, mitochondrial function and the expressions of IL-22, IL-22R1, p-STAT3^Tyr705. We discovered that Ac2-26 reduced the Suzuki score and cell death rate, and increased the cell viability after HIRI. Moreover, we unraveled that Ac2-26 significantly decreased the number of apoptotic hepatocytes, and the expressions of cleaved-caspase-3 and Bax/Bcl-2 ratio. Furthermore, HIRI increased the contents of malondialdehyde (MDA), NADP⁺/NADPH ratio and reactive oxygen species (ROS), whereas Ac2-26 decreased them significantly. Additionally, Ac2-26 remarkably alleviated mitochondria dysfunction, which was represented by an increase in the adenosine triphosphate (ATP) content and mitochondrial membrane potential, a decrease in mitochondrial DNA (mtDNA) damage. Finally, we revealed that Ac2-26 pretreatment could significantly inhibit the activation of IL-22/IL22R1/STAT3 signaling. In conclusion, this work demonstrated that Ac2-26 ameliorated HIRI by reducing oxidative stress and inhibiting the mitochondrial apoptosis pathway, which might be closely related to the inhibition of the IL-22/IL22R1/STAT3 signaling pathway.

Magnesium in renal fibrosis

PURPOSE

Renal fibrosis (RF) is the main pathological feature of chronic kidney disease (CKD). The main focus of research on treatment for CKD is to develop strategies that delay or prevent RF from progressing to end-stage renal disease (ESRD). Inflammation and oxidative stress occur during all stages of CKD. The magnesium cation (Mg²⁺) can reduce inflammation and oxidative stress, regulate apoptosis, and improve RF, and magnesium-based therapies are promising new treatments that can prevent RF. We reviewed the current evidence on the effects of magnesium in RF and examined the possible mechanism of magnesium in delaying RF.

METHODS

We searched PubMed, Web of Science, and EMBASE for articles on magnesium and fibrosis, with a focus on magnesium and RF.

RESULTS

Inflammation, oxidative stress, and apoptosis are related to the occurrence of CKD. Previous research showed that Mg²⁺ inhibits the differentiation of inflammatory cells, down-regulates the production of inflammatory cytokines, reduces inflammation, and reduces the production of reactive oxygen species (ROS) and oxidative stress. In addition, Mg²⁺ also regulates apoptosis and protects renal tubular function. Magnesium may also regulate TRPM6/7, promote the secretion of klotho protein and improve renal fibrosis. Therefore, Mg²⁺ can protect the kidney from damage and slow down the progression of RF through many molecular and cellular effects. Some of the anti-fibrotic effects of Mg²⁺ may be related to its antagonism of intracellular Ca²⁺.

CONCLUSION

Magnesium may prevent the progression of renal fibrosis and delay CKD by reducing renal inflammation and oxidative stress, and by regulating fibrosis-related signaling pathways and cytokines.

Genistein-3'-sodium sulfonate ameliorates cerebral ischemia injuries by blocking neuroinflammation through the α7nAChR-JAK2/STAT3 signaling pathway in rats

BACKGROUND

Neuroinflammation plays a pivotal role in the acute progression of cerebral ischemia/reperfusion injury (I/RI). We previously reported that genistein-3'-sodium sulfonate (GSS), a derivative from the extract of the phytoestrogen genistein (Gen), protects cortical neurons against focal cerebral ischemia. However, the molecular mechanism underlying the neuroprotective effects exerted by GSS remains unclear.

PURPOSE

The present study focused on the anti-inflammatory effects of GSS following I/RI in rats.

STUDY DESIGN

Randomized controlled trial.

METHODS

The tMCAO rat model and LPS-stimulated BV2 in vitro model were used. Longa's scare was used to observe neurological function. TTC staining and Nissl staining were used to evaluate brain injury. ELISA, qRT-PCR, Western blotting and immunofluorescent staining methods were used to detect cytokine concentration, mRNA level, protein expression and location.

RESULTS

GSS treatment improves neurological function, reduces the volume of cerebral infarction, attenuates proinflammatory cytokines and inactivates the phosphorylation of JAK2 and STAT3 in I/RI rats. Furthermore, GSS increased the expression of α7nAChR. More importantly, the neuroprotective, anti-inflammatory and inhibiting JAK2/STAT3 signaling pathway effects of GSS were counteracted in the presence of alpha-bungarotoxin (α-BTX), an α7nAChR inhibitor, suggesting that α7nAChR is a potential target associated with the anti-inflammatory effects of GSS in the I/RI rats. GSS also inhibited BV2 cells from releasing IL-1β via the α7nAChR pathway after LPS stimulation.

CONCLUSION

GSS protects against cerebral I/RI through the expression of α7nAChR and inhibition of the JAK2/STAT3 pathway. Our findings provide evidence for the role of the cholinergic anti-inflammatory pathway in neuroinflammation and uncover a potential novel mechanism for GSS treatment in ischemic stroke. The downstream signals of GSS, α7nAChR- JAK2/STAT3 could also be potential targets for the treatment of I/RI.

The bidirectional role of the JAK2/STAT3 signaling pathway and related mechanisms in cerebral ischemia-reperfusion injury

The Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway, a well-conserved and basic intracellular signaling cascade, is mostly inactivated under basal conditions, although it can be phosphorylated under extracellular stimulation; in addition, it can influence the transcription and expression of multiple genes involved in biological processes such as cellular growth, metabolism, differentiation, degradation and angiogenesis. The inflammatory response, apoptosis, oxidative stress and angiogenesis are the main factors involved in the pathogenesis of ischemic stroke. Numerous studies have confirmed that the JAK2/STAT3 axis can be activated rapidly by ischemic stress, which is closely related to the regulation of these important pathological processes. However, different opinions on the specific role of this signaling pathway remain. In this paper, we review and summarize previous studies on the JAK2/STAT3 pathway in ischemic stroke.

Anti-Fibrosis Effects of Magnesium Lithospermate B in Experimental Pulmonary Fibrosis: By Inhibiting TGF-βRI/Smad Signaling

Pulmonary fibrosis is a severe and irreversible interstitial pulmonary disease with high mortality and few treatments. Magnesium lithospermate B (MLB) is a hydrosoluble component of Salvia miltiorrhiza and has been reported to have antifibrotic effects in other forms of tissue fibrosis. In this research, we studied the effects of MLB on pulmonary fibrosis and the underlying mechanisms. Our results indicated that MLB treatment (50 mg/kg) for seven days could attenuate bleomycin (BLM)-induced pulmonary fibrosis by reducing the alveolar structure disruption and collagen deposition in the C57 mouse model. MLB was also found to inhibit transforming growth factor-beta (TGF-β)-stimulated myofibroblastic transdifferentiation of human lung fibroblast cell line (MRC-5) cells and collagen production by human type II alveolar epithelial cell line (A549) cells, mainly by decreasing the expression of TGF-β receptor I (TGF-βRI) and regulating the TGF-β/Smad pathway. Further studies confirmed that the molecular mechanisms of MLB in BLM-induced pulmonary fibrosis mice were similar to those observed in vitro. In summary, our results demonstrated that MLB could alleviate experimental pulmonary fibrosis both in vivo and in vitro, suggesting that MLB has great potential for pulmonary fibrosis treatment.

Gigantol ameliorates CCl4-induced liver injury via preventing activation of JNK/cPLA2/12-LOX inflammatory pathway

Arachidonic acid (AA) signaling pathway is an important constituent of inflammatory processes. In our previous study, it was found that dihydro-stilbene gigantol relieved hepatic inflammation in mice with CCl₄-induced acute liver injury. This study aimed to investigate the involvement of arachidonate metabolic cascade in this process. Our results showed CCl₄ activated AA metabolism with the evidence of cPLA2 phosphorylation, which was dependent on the MAPK/JNK activation. Pretreatment with JNK inhibitor SU3327 or gigantol abolished the cPLA2 activation, along with the attenuation of liver damage. Besides, gigantol markedly decreased immune cells activation. Metabolomic analysis revealed that gigantol universally reversed the upregulation of major AA metabolites in injured mouse livers induced by CCl₄, especially 12-hydroxyeicosatetraenoic acid (12-HETE). Gigantol also decreased the mRNA and protein expression of platelet-, and leukocyte-type 12-lipoxxygenase (LOX) in the liver. Furthermore, pan-LOX inhibitor nordihydroguaiaretic acid (NDGA) and specific 12-LOX inhibitors baicalein and ML351 attenuated the liver injury to the same extent as gigantol. Overall, our study elucidated a comprehensive profile of AA metabolites during hepatic inflammation caused by CCl₄, highlighting the role of 12-LOX-12-HETE pathway in this process. And gigantol alleviated liver inflammation partly through inhibiting the JNK/cPLA2/12-LOX pathway.

SIRT1 alleviates hepatic ischemia-reperfusion injury via the miR-182-mediated XBP1/NLRP3 pathway

The hepatoprotection of histone deacetylase sirtuin 1 (SIRT1) has been identified to attenuate ischemia-reperfusion (IR)-triggered inflammation and liver damage. This study was performed to characterize the function of SIRT1 in hepatic IR injury. In in vivo assays on liver-specific knockout mice of SIRT1, we first validated the effect of SIRT1 knockout on liver damage and XBP1/NLRP3 inflammasome activation. Next, we examined whether knockdown of XBP1/NLRP3 or miR-182 agomir could reverse the effect of SIRT1 knockout. In in vitro assays, NCTC1469 cells subjected to hypoxia/reoxygenation (H/R) were transduced with small interfering RNA (siRNA)/activator of SIRT1 or miR-182 agomir to confirm the effect of SIRT1 on NCTC1469 cell behaviors as well as the regulation of miR-182 and the XBP1/NLRP3 signaling pathway. Hepatic IR injury was appreciably aggravated in SIRT1 knockout mice, and SIRT1 knockdown abolished the inhibition of XBP1/NLRP3 inflammasome activation, which was reversed by NLRP3 knockdown, XBP1 knockdown, or miR-182 agomir. Mechanistically, miR-182 expression was positively regulated by SIRT1 in hepatic IR injury in mice, and miR-182 inhibited the expression of XBP1 by binding to the 3' untranslated region (UTR) of XBP1. The histone deacetylase SIRT1 inhibits the downstream XBP1/NLRP3 inflammatory pathway by activating miR-182, thus alleviating hepatic IR injury in mice.

Magnesium Lithospermate B Downregulates the Levels of Blood Pressure, Inflammation, and Oxidative Stress in Pregnant Rats with Hypertension

Background

Magnesium lithospermate B (MLB) was shown to suppress oxidative stress and reduce hypertension, but the role of MLB in pregnancy-induced hypertension (PIH) remains unknown. The objective of this study was to demonstrate the effects of MLB on rats with PIH.

Methods

A total of 40 pregnant SD rats were selected, and 30 rats were orally given NG-nitro-L-arginine methyl ester (L-NAME, 60 mg/kg/day) to establish PIH rat models. Rats were equally divided into four groups: control, PIH, 5 mg/kg MLB, and 10 mg/kg MLB. MLB was consecutively administered into PIH rats for one week. The effects of MLB on mean arterial blood pressure (MAP), urine protein level, inflammation, and oxidative stress together with angiogenesis were analyzed.

Results

MLB prevented the elevation in MAP and urine protein levels induced by L-NAME. The activities of inflammatory cytokines were highly increased in serum and placental tissues of PIH rats, while cotreatment with MLB partially reversed the activities of these cytokines. MLB also recovered the expression of reactive oxygen species (ROS) in plasma of PIH rats together with levels of oxidative stress and antioxidant capacity in the placenta of PIH rats. The decreased expressions of vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), and NO observed in PIH rats were increased by MLB. In addition, 10 mg/kg MLB exhibited higher protective effects as compared to lower doses of 5 mg/kg.

Conclusion

This study demonstrated that pretreatment with MLB decreased MAP, inflammation, and oxidative stress in rats with gestational hypertension.

Geraniol activates Nrf-2/HO-1 signaling pathway mediating protection against oxidative stress-induced apoptosis in hepatic ischemia-reperfusion injury

Geraniol (GOH) is a natural essential oil that possesses antioxidant, anti-inflammatory, and antiapoptotic properties by various signaling pathways. Liver ischemia-reperfusion injury (IRI) is a serious event that triggers liver dysfunction or even failure. Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcriptional factor, maintains cellular defense mechanism through antioxidant and anti-inflammatory properties. To detect GOH effect against liver IRI through the activation of the Nrf2/HO-1 antioxidant pathway, five groups of rats were randomized to normal, sham, IR, GOH, and GOH/IR. Blood samples and liver tissues were collected to measure various biochemical parameters related to liver function, and oxidative stress as well as inflammatory and apoptotic indicators besides liver tissue histopathology was evaluated by light microscopy. GOH induces activation of Nrf2 along with the upregulation of HO-1 expression. Also, the antioxidant activity of GOH was shown by the elevation of total antioxidant capacity and GSH levels, together with normalizing malondialdehyde. Regarding the anti-inflammatory effect of GOH, it suppresses the levels of TNF-α, iNOS, and COX-2. Additionally, the antiapoptotic effect of GOH, Bax, and caspase-3, 9 were reduced in liver tissue. GOH is a promising hepatoprotective agent in liver IRI through the activation of Nrf2/HO-1 antioxidant pathway.