Inhibition of CKLF1 ameliorates hepatic ischemia-reperfusion injury via MAPK pathway

Modafinil lightens apoptosis and inflammatory response in hepatic ischemia-reperfusion injury through inactivation of TLR9/Myd88/p38 signaling

Hepatic ischemia/reperfusion injury (IRI) remains a severe threat during liver surgery and transplantation, accounting for unfavorable clinical outcomes. Modafinil (MOD), a wakefulness-inducing compound, is increasingly disclosed to protect against IRI. However, the specific literatures covering the association between MOD and hepatic IRI are few. Here, this paper is committed to unraveling the role and response mechanism of MOD in hepatic IRI. After the establishment of hepatic IRI mice model and cell model, relevant assay kits measured the concentrations of biochemical indicators of hepatotoxicity and hematoxylin and eosin staining estimated liver morphology. Enzyme-linked immunosorbent assay, reverse-transcription quantitative polymerase chain reaction, and western blot evaluated inflammatory levels. Terminal-deoxynucleoitidyl transferase-mediated nick end labeling assay and western blot appraised apoptosis. Western blot also analyzed the expression of Toll-like receptor 9 (TLR9)/myeloid differentiation primary response gene 88 (MyD88)/p38 signaling-associated proteins. Cell counting kit-8 method judged cell viability. MOD was discovered to mitigate liver dysfunction and morphological damage, inflammatory response, apoptosis in vivo and improve cell viability, suppress inflammatory response and apoptosis in vitro. In addition, MOD inactivated TLR9/Myd88/p38 signaling both in vitro and in vivo. Further, TLR9 elevation reversed the inhibitory role of MOD in inflammatory response and cell apoptosis in vitro. Anyway, MOD blocked TLR9/Myd88/p38 signaling to exhibit anti-inflammatory and anti-apoptotic properties in hepatic IRI.

CKLF1, transcriptionally activated by FOXC1, promotes hypoxia/reoxygenation‑induced oxidative stress and inflammation in H9c2 cells by NLRP3 inflammasome activation

Myocardial ischemia/reperfusion (I/R) injury is a clinical challenge in the treatment of ischemic heart disease. The present study aimed to establish a hypoxia/reoxygenation (H/R)-induced H9c2 cell model to explore the role and mechanism of chemokine-like factor 1 (CKLF1) in myocardial I/R injury. First, CKLF1 expression was measured in H/R-induced H9c2 cells by reverse transcription-quantitative PCR and western blotting. Subsequently, after CKLF1 silencing, cell viability and apoptosis were evaluated by Cell Counting Kit-8 assay and flow cytometry. In addition, 2,7-dichlorodihydrofluorescein diacetate staining was used to assess the levels of cellular reactive oxygen species. Additionally, the levels of superoxide dismutase, glutathione peroxidase and malondialdehyde, and the contents of inflammatory factors IL-6, IL-1β and TNF-α were detected using corresponding commercially available kits. Western blotting was used to examine the expression levels of proteins involved in the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome. The JASPAR database predicted that forkhead box protein C1 (FOXC1) would bind to the CKLF1 promoter region, and dual luciferase and chromatin immunoprecipitation assays were performed to verify it. Subsequently, FOXC1 overexpression and CKLF1 silencing were used to clarify the regulatory mechanism of FOXC1 on CKLF1 in H/R-induced H9c2 cells. The results revealed that CKLF1 expression was markedly enhanced in H/R-stimulated H9c2 cells. CKLF1 knockdown enhanced the viability and inhibited the apoptosis of H9c2 cells exposed to H/R. Moreover, the oxidative stress and inflammation induced by H/R were alleviated following CKLF1 silencing. CKLF1 knockdown also inhibited NLRP3 inflammasome activation. Furthermore, FOXC1 bound to the CKLF1 promoter region to upregulate CKLF1 expression, and FOXC1 overexpression alleviated the effects of CKLF1 knockdown on H9c2 cell damage induced by H/R via activation of the NLRP3 inflammasome. In conclusion, CKLF1 transcriptionally activated by FOXC1 may promote H/R-induced oxidative stress and inflammation in H9c2 cells via NLRP3 inflammasome activation.

Tetrandrine attenuates SNI-induced mechanical allodynia by inhibiting spinal CKLF1

Neuropathic pain (NP) is a prevalent clinical problem for which satisfactory treatment options are unavailable. Tetrandrine (TET), a bisbenzylisoquinoline alkaloid extracted from Stephania tetrandra S. Moore, possesses anti-inflammatory and immune-modulatory properties. Chemokine-like factor 1 (CKLF1) is known to play a crucial role in both peripheral and central inflammatory processes. This study aimed to investigate the potential anti-NP effects of TET and the involvement of CKLF1 in the action of TET. A male C57BL/6J mice model of NP caused by spared nerve injury (SNI) was established and mechanical withdrawal thresholds were measured using von Frey filaments. The results showed that TET improved mechanical allodynia in SNI mice and the propofol-induced sleep assay demonstrated that the TET group did not exhibit central inhibition, while the pregabalin (PGB) group showed significant central inhibition. Western blotting and immunofluorescence staining showed that TET significantly inhibited spinal protein expression levels of CKLF1, p-NF-κB/NF-κB, p-IKK/IKK, pro-inflammatory cytokines IL-1β and TNF-α, and increased protein expression levels of the anti-inflammatory cytokine IL-10, while inhibiting the expression levels of microglia and astrocyte markers IBA-1 and GFAP of SNI mice. Moreover, immunofluorescence double-labeling results revealed that CKLF1 was predominantly colocalized with microglia of the spinal cord (SC) in SNI mice. C19 (an antagonism peptide of CKLF1) alleviated SNI-induced mechanical pain hypersensitivity, while C27 (an analog peptide of CKLF1) induced mechanical allodynia in normal mice. TET significantly attenuated mechanical allodynia induced by C27 in mice. TET may effectively alleviate NP by reducing neuroinflammation and decreasing CKLF1.

Mitogen activated protein kinase phosphatase 5 alleviates liver ischemia-reperfusion injury by inhibiting TAK1/JNK/p38 pathway

Mitogen activated protein kinase phosphatase 5 (MKP5) is a member of the MKP family and has been implicated in diverse biological and pathological conditions. However, it is unknown what role MKP5 plays in liver ischemia/reperfusion (I/R) injury. In the present study, we used MKP5 global knockout (KO) and MKP5 overexpressing mice to establish a liver I/R injury model in vivo, and MKP5 knockdown or MKP5 overexpressing HepG2 cells to establish a hypoxia-reoxygenation (H/R) model in vitro. In this study we demonstrated that protein expression of MKP5 was significantly downregulated in liver tissue of mice after I/R injury, and HepG2 cells subjected to H/R injury. MKP5 KO or knockdown significantly increased liver injury, as demonstrated by elevated serum transaminases, hepatocyte necrosis, infiltrating inflammatory cells, secretion of pro-inflammatory cytokines, apoptosis, oxidative stress. Conversely, MKP5 overexpression significantly attenuated liver and cell injury. Furthermore, we showed that MKP5 exerted its protective effect by inhibiting c-Jun N-terminal kinase (JNK)/p38 activity, and its action was dependent on Transforming growth factor-β-activated kinase 1 (TAK1) activity. According to our results, MKP5 inhibited the TAK1/JNK/p38 pathway to protect liver from I/R injury. Our study identifies a novel target for the diagnosis and treatment of liver I/R injury.

Dexmedetomidine attenuates hepatic ischemia-reperfusion injury-induced apoptosis via reducing oxidative stress and endoplasmic reticulum stress

Dexmedetomidine (DEX) affords a hepatoprotective effect during ischemia-reperfusion (IR) injury (IRI); however, the underlying mechanism remains elusive. In this work, using a rat liver IR model and a BRL-3A cell hypoxia-reoxygenation (HR) model, we explored whether DEX protects the liver against IRI by decreasing oxidative stress (OS), endoplasmic reticulum stress (ERS), and apoptotic pathways. We found that DEX significantly increased SOD and GSH activity while decreasing ROS and MDA levels in BRL-3A cells, successfully preventing HR-induced OS damage. DEX administration reduced JNK, ERK, and P38 phosphorylation and blocked HR-induced MAPK signaling pathway activation. Additionally, DEX administration reduced the expression of GRP78, IRE1α, XBP1, TRAF2, and CHOP, which reduced HR-induced ERS. NAC prevented the MAPK pathway from being activated and inhibited the ERS pathway. Further research showed that DEX significantly reduced HR-induced apoptosis by suppressing the expression of Bax/Bcl-2 and cleaved caspase-3. Similarly, animal studies demonstrated DEX exerted a protective effect of the liver by alleviating histopathological injury and enhancing liver function, mechanically DEX reduced cell apoptosis in liver tissue by reducing oxidative stress and ERS. In conclusion, DEX mitigates OS and ERS during IR, thereby suppressing cell apoptosis, thus providing protection to the liver.

MAPK Signaling Pathways in Hepatic Ischemia/Reperfusion Injury

The mitogen-activated protein kinase signaling pathway can be activated by a variety of growth factors, cytokines, and hormones, and mediates numerous intracellular signals related to cellular activities, including cell proliferation, motility, and differentiation. It has been widely studied in the occurrence and development of inflammation and tumor. Hepatic ischemia-reperfusion injury (HIRI) is a common pathophysiological phenomenon that occurs in surgical procedures such as lobectomy and liver transplantation, which is characterized by severe inflammatory reaction after ischemia and reperfusion. In this review, we mainly discuss the role of p38, ERK1/2, JNK in MAPK family and TAK1 and ASK1 in MAPKKK family in HIRI, and try to find an effective treatment for HIRI.

Role of chemokine-like factor 1 as an inflammatory marker in diseases

Immunoinflammatory mechanisms have been incrementally found to be involved in the pathogenesis of multiple diseases, with chemokines being the main drivers of immune cell infiltration in the inflammatory response. Chemokine-like factor 1 (CKLF1), a novel chemokine, is highly expressed in the human peripheral blood leukocytes and exerts broad-spectrum chemotactic and pro-proliferative effects by activating multiple downstream signaling pathways upon binding to its functional receptors. Furthermore, the relationship between CKLF1 overexpression and various systemic diseases has been demonstrated in both in vivo and in vitro experiments. In this context, it is promising that clarifying the downstream mechanism of CKLF1 and identifying its upstream regulatory sites can yield new strategies for targeted therapeutics of immunoinflammatory diseases.

New insights into ischemia-reperfusion injury signaling pathways in organ transplantation

PURPOSE OF REVIEW

Ischemia-reperfusion injury (IRI) leading to allograft rejection in solid organ transplant recipients is a devastating event that compromises graft and patient survival. As our clinical knowledge regarding its definition and presentation has significantly improved over the last years, adequate biomarkers translating to important therapeutic intervention remains a challenge. This review will summarize recent findings in this area.

RECENT FINDINGS

In the past 18 months, our understanding of organ transplantation IRI has improved. IRI involves a positive amplification feedback loop encompassing damaged cells at the graft site, the activity of redox-sensitive damage-associated molecular patterns, and local sequestration of recipient-derived monocytes, lymphocytes and polymorphonuclear leukocytes, like neutrophils, to sustain the immunological cascade and to enhance the destruction of the foreign tissue. Recent studies have identified critical components leading to IRI, including the oxidation state of high mobility group box 1, a classic danger signal, its role in the Toll-like receptor 4-interleukin (IL)-23-IL-17A signaling axis, and the role of neutrophils and CD321, a marker for transmigration of circulating leukocytes into the inflamed tissue. In addition, recent findings imply that the protective functions mediated by autophagy activation counterbalance the detrimental nucleotide-binding domain-like receptor family, pyrin domain containing 3 inflammasome pathway. Finally, clinical studies reveal the posttransplant variables associated with early allograft dysfunction and IRI.

SUMMARY

The future challenge will be understanding how crosstalk at the molecular and cellular levels integrate prospectively to predict which peri-transplant signals are essential for long-term clinical outcomes.

The Preventive Effect of Cardiac Sympathetic Denervation Induced by 6-OHDA on Myocardial Ischemia-Reperfusion Injury: The Changes of lncRNA/circRNAs-miRNA-mRNA Network of the Upper Thoracic Spinal Cord in Rats

In this study, we investigated whether chemical 6-hydroxydopamine (6-OHDA) stimuli caused cardiac sympathetic denervation (SD), and we analyzed gene expression profiles to determine the changes in the lncRNA/circRNAs-miRNA-mRNA network in the affected spinal cord segments to identify putative target genes and molecular pathways in rats with myocardial ischemia–reperfusion injury (MIRI). Our results showed that cardiac sympathetic denervation induced by 6-OHDA alleviated MIRI. Compared with the ischemia reperfusion (IR, MIRI model) group, there were 148 upregulated and 51 downregulated mRNAs, 165 upregulated and 168 downregulated lncRNAs, 70 upregulated and 52 downregulated circRNAs, and 12 upregulated and 11 downregulated miRNAs in the upper thoracic spinal cord of the SD-IR group. Furthermore, we found that the differential genes related to cellular components were mainly enriched in extracellular and cortical cytoskeleton, and molecular functions were mainly enriched in chemokine activity. Pathway analysis showed that the differentially expressed genes were mainly related to the interaction of cytokines and cytokine receptors, sodium ion reabsorption, cysteine and methionine metabolism, mucoglycan biosynthesis, cGMP-PKG signaling pathway, and MAPK signaling pathway. In conclusion, the lncRNA/circRNAs-miRNA-mRNA networks in the upper thoracic spinal cord play an important role in the preventive effect of cardiac sympathetic denervation induced by 6-OHDA on MIRI, which offers new insights into the pathogenesis of MIRI and provides new targets for MIRI.