PACAP neuropeptide promotes Hepatocellular Protection via CREB-KLF4 dependent autophagy in mouse liver Ischemia Reperfusion Injury.

Organ ischemia reperfusion injury (IRI), associated with acute hepatocyte death, remains an unresolved problem in clinical orthotopic liver transplantation (OLT). Autophagy, an intracellular self-digesting progress, is responsible for cell reprograming required to regain post-stress homeostasis. Methods: Here, we analyzed the cytoprotective mechanism of pituitary adenylate cyclase-activating polypeptide (PACAP)-promoted hepatocellular autophagy in a clinically relevant mouse model of extended hepatic cold storage (4 °C UW solution for 20 h) followed by syngeneic OLT. Results: In contrast to 41.7% of liver graft failure by day 7 post-transplant in control group, PACAP treatment significantly improved graft survival (91.7% by day 14), and promoted autophagy-associated regeneration programs in OLT. In parallel in vitro studies, PACAP-enhanced autophagy ameliorated cellular damage (LDH/ALT levels), and diminished necrosis in H2O2-stressed primary hepatocytes. Interestingly, PACAP not only induced nuclear cAMP response element-binding protein (CREB), but also triggered reprogramming factor Kruppel-like factor 4 (KLF4) expression in IR-stressed OLT. Indeed, CREB inhibition attenuated hepatic autophagy and recreated hepatocellular injury in otherwise PACAP-protected livers. Furthermore, CREB inhibition suppressed PACAP-induced KLF4 expression, whereas KLF4 blockade abolished PACAP-promoted autophagy and neutralized PACAP-mediated hepatoprotection both in vivo and in vitro. Conclusion: Current study documents the essential neural regulation of PACAP-promoted autophagy in hepatocellular homeostasis in OLT, which provides the emerging therapeutic principle to combat hepatic IRI in OLT

Multiple large shareholders, blockholder trading and stock price crash risk

We show that in a setting with a strong concern for controlling shareholder entrenchment, firms with multiple large shareholders (MLS) are more likely to experience stock price crashes. As a result, when anticipating future revelations of bad news concerning corporate misconduct on information disclosure, large shareholders can exploit their information advantage and initiate their sales ex ante as far as eight quarters ahead. The positive association between MLS and crashes is more pronounced in the presence of noncontrolling shareholders' sales. Also, the positive predictive power of MLS on crash risk is more potent in firms with weak internal or external governance.</p

Selectivity of Oxygen Evolution Reaction on Carbon Cloth-Supported δ-MnO₂ Nanosheets in Electrolysis of Real Seawater

Electrolysis of seawater using solar and wind energy is a promising technology for hydrogen production which is not affected by the shortage of freshwater resources. However, the competition of chlorine evolution reactions and oxygen evolution reactions on the anode is a major obstacle in the upscaling of seawater electrolyzers for hydrogen production and energy storage, which require chlorine-inhibited oxygen evolution electrodes to become commercially viable. In this study, such an electrode was prepared by growing δ-MnO2 nanosheet arrays on the carbon cloth surface. The selectivity of the newly prepared anode towards the oxygen evolution reaction (OER) was 66.3% after 30 min of electrolyzer operation. The insertion of Fe, Co and Ni ions into MnO2 nanosheets resulted in an increased number of trivalent Mn atoms, which had a negative effect on the OER selectivity. Good tolerance of MnO2/CC electrodes to chlorine evolution in seawater electrolysis indicates its suitability for upscaling this important energy conversion and storage technology

Inhibition of Cyclin-dependent Kinase 2 Signaling Prevents Liver Ischemia and Reperfusion Injury

BackgroundLiver ischemia and reperfusion injury (IRI) is a major complication of liver transplant, hepatectomy, and hemorrhagic shock. The cyclin-dependent kinase 2 (CDK2) acts as a pivotal regulator of cell cycle and proliferation.MethodsThis study evaluated the modulation and therapeutic potential of CDK2 inhibition in a mouse model of partial liver warm IRI.ResultsLiver IR-triggered intrinsic CDK2 expression, peaking by 0.5 hour of reperfusion and maintaining a high-level throughout 1 to 24 hours. Roscovitine, a specific CDK2 inhibitor, prevented liver IR-mediated damage with abolished serum alanine aminotransferase levels and reserved liver pathology. CDK2 inhibition-mediated liver protection was accompanied by decreased macrophage/neutrophil infiltration, diminished hepatocyte apoptosis, abolished toll like receptor 4 signaling and downstream gene inductions (C-X-C motif ligand-10, Tumor necrosis factor-α, interleukin-1β, and interleukin-6), yet augmented interleukin-10 expression. In vitro, CDK2 inhibition by Roscovitine suppressed macrophage TLR4 activation and further depressed downstream inflammatory signaling (myeloid differentiation factor 88, interferon regulatory transcription factor 3, p38, c-Jun N-terminal kinase, and extracellular-regulated kinase).ConclusionsOur novel findings revealed the critical role of CDK2 in hepatic cytoprotection and homeostasis against liver IRI. As CDK2 inhibition regulated local immune response and prevented hepatocyte death, this study provided the evidence for new treatment approaches to combat IRI in liver transplant

T-cell immunoglobulin and mucin domain 4 (TIM-4) signaling in innate immune-mediated liver ischemia-reperfusion injury.

UnlabelledHepatic ischemia-reperfusion injury (IRI), an innate immunity-driven inflammation response, occurs in multiple clinical settings including liver resection, transplantation, trauma, and shock. T-cell immunoglobulin and mucin (TIM)-4, the only TIM protein not expressed on T cells, is found on macrophages and dendritic cells. The regulatory function of macrophage TIM-4 in the engulfment of apoptotic/necrotic bodies in innate immunity-mediated disease states remains unknown. This study focuses on the putative role of TIM-4 signaling in a model of liver warm ischemia (90 minutes) and reperfusion. The ischemia insult triggered TIM-4 expression by stressed hepatocellular phosphatidylserine (PS) presentation, peaking at 6 hours of reperfusion, and coinciding with the maximal hepatocellular damage. TIM-4-deficient or wild-type WT mice treated with antagonistic TIM-4 monoclonal antibody (mAb) were resistant against liver IRI, evidenced by diminished serum alanine aminotransferase (sALT) levels and well-preserved hepatic architecture. Liver hepatoprotection rendered by TIM-4 deficiency was accompanied by diminished macrophage infiltration/chemoattraction, phagocytosis, and activation of Toll-like receptor (TLR)2/4/9-dependent signaling. Correlating with in vivo kinetics, the peak of TIM-4 induction in lipopolysaccharide (LPS)-activated bone marrow derived-macrophages (BMM) was detected in 6-hour cultures. To mimic liver IRI, we employed hydrogen peroxide-necrotic hepatocytes, which readily present PS. Indeed, necrotic hepatocytes were efficiently captured/engulfed by WT (TIM-4+) but not by TIM-4-deficient BMM. Finally, in a newly established model of liver IRI, adoptive transfer of WT but not TIM-4-deficient BMM readily recreated local inflammation response/hepatocellular damage in the CD11b-DTR mouse system.ConclusionThese findings document the importance of macrophage-specific TIM-4 activation in the mechanism of hepatic IRI. Macrophage TIM-4 may represent a therapeutic target to minimize innate inflammatory responses in IR-stressed organs

Activation of YAP attenuates hepatic damage and fibrosis in liver ischemia-reperfusion injury.

Background &amp; aimsHepatic ischemia-reperfusion injury (IRI) is a major complication of hemorrhagic shock, liver resection and transplantation. YAP, a key downstream effector of the Hippo pathway, is essential for determining cell fate and maintaining homeostasis in the liver. We aimed to elucidate its role in IRI.MethodsThe role of YAP/Hippo signaling was systematically studied in biopsy specimens from 60 patients after orthotopic liver transplantation (OLT), and in a mouse model of liver warm IRI. Human biopsy specimens were collected after 2-10 h of cold storage and 3 h post-reperfusion, before being screened by western blot. In the mouse model, the role of YAP was probed by activating or inhibiting YAP prior to ischemia-reperfusion.ResultsIn human biopsies, high post-OLT YAP expression was correlated with well-preserved histology and improved hepatocellular function at postoperative day 1-7. In mice, the ischemia insult (90 min) triggered intrinsic hepatic YAP expression, which peaked at 1-6 h of reperfusion. Activation of YAP protected the liver against IR-stress, by promoting regenerative and anti-oxidative gene induction, while diminishing oxidative stress, necrosis/apoptosis and the innate inflammatory response. Inhibition of YAP aggravated hepatic IRI and suppressed repair/anti-oxidative genes. In mouse hepatocyte cultures, activating YAP prevented hypoxia-reoxygenation induced stress. Interestingly, YAP activation suppressed extracellular matrix synthesis and diminished hepatic stellate cell (HSC) activation, whereas YAP inhibition significantly delayed hepatic repair, potentiated HSC activation, and enhanced liver fibrosis at 7 days post-IRI. Notably, YAP activation failed to protect Nrf2-deficient livers against IR-mediated damage, leading to extensive fibrosis.ConclusionOur novel findings document the crucial role of YAP in IR-mediated hepatocellular damage and liver fibrogenesis, providing evidence of a potential therapeutic target for the management of sterile liver inflammation in transplant recipients.Lay summaryIn the clinical arm, graft YAP expression negatively correlated with liver function and tissue damage after human liver transplantation. YAP activation attenuated hepatocellular oxidative stress and diminished the innate immune response in mouse livers following ischemia-reperfusion injury. In the mouse model, YAP inhibited hepatic stellate cell activation, and abolished injury-mediated fibrogenesis up to 7 days after the ischemic insult

Vasoactive intestinal peptide attenuates liver ischemia/reperfusion injury in mice via the cyclic adenosine monophosphate-protein kinase a pathway.

Hepatic ischemia/reperfusion injury (IRI), an exogenous, antigen-independent, local inflammation response, occurs in multiple clinical settings, including liver transplantation, hepatic resection, trauma, and shock. The nervous system maintains extensive crosstalk with the immune system through neuropeptide and peptide hormone networks. This study examined the function and therapeutic potential of the vasoactive intestinal peptide (VIP) neuropeptide in a murine model of liver warm ischemia (90 minutes) followed by reperfusion. Liver ischemia/reperfusion (IR) triggered an induction of gene expression of intrinsic VIP; this peaked at 24 hours of reperfusion and coincided with a hepatic self-healing phase. Treatment with the VIP neuropeptide protected livers from IRI; this was evidenced by diminished serum alanine aminotransferase levels and well-preserved tissue architecture and was associated with elevated intracellular cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) signaling. The hepatocellular protection rendered by VIP was accompanied by diminished neutrophil/macrophage infiltration and activation, reduced hepatocyte necrosis/apoptosis, and increased hepatic interleukin-10 (IL-10) expression. Strikingly, PKA inhibition restored liver damage in otherwise IR-resistant VIP-treated mice. In vitro, VIP not only diminished macrophage tumor necrosis factor α/IL-6/IL-12 expression in a PKA-dependent manner but also prevented necrosis/apoptosis in primary mouse hepatocyte cultures. In conclusion, our findings document the importance of VIP neuropeptide-mediated cAMP-PKA signaling in hepatic homeostasis and cytoprotection in vivo. Because the enhancement of neural modulation differentially regulates local inflammation and prevents hepatocyte death, these results provide the rationale for novel approaches to managing liver IRI in transplant patients

Pituitary Adenylate Cyclase-Activating Polypeptides Prevent Hepatocyte Damage by Promoting Yes-associated Protein in Liver Ischemia/Reperfusion Injury.

BACKGROUND:Hepatic ischemia-reperfusion injury (IRI) is a severe complication in liver transplantation, hepatectomy and hemorrhagic shock. As neuropeptides transmit the regulatory signal between nervous-immune systems communication, our previous study documented that pituitary adenylate cyclase-activating polypeptides (PACAP) depressed hepatic TLR4 immune response in liver IRI. METHODS:Here, we focused on how PACAP suppressed hepatocellular damage and enhanced hepatocyte regeneration in a murine model of partial liver warm IRI. RESULTS:Yes-associated protein (YAP), a cellular modulator of tissue regeneration, was readily induced in WT IR-livers. As its induction was failed in PACAP-deficient livers, PACAP supplement enhanced YAP expression in WT mouse, promoted its nuclear translocation and downstream anti-oxidative/regenerative genes expression both in vivo and in vitro. Further, verteporfin (VP), a YAP transcriptional inhibitor, abolished PACAP-mediated hepatoprotection significantly. Meanwhile, blockade of PKA-CREB signaling recreated liver damage in PACAP-protected liver, as well as impeded stimulation on YAP and its downstream gene expressions. Consistently, inhibition of PKA-CREB decreased PACAP promoted YAP expression in primary hepatocytes culture, and made them vulnerable to H2O2 stress in vitro. In addition, lysophosphatidic acid (LPA), another Hippo pathway inhibitor, failed to affect PACAP-mediated hepatoprotection or hepatocellular YAP induction. This implies that PACAP regulated YAP through PKA-CREB pathway at the transcriptional level rather than canonical hippo pathway. CONCLUSION:Our study discovered the neural modulation of PACAP-YAP axis in hepatic cytoprotection and homeostasis in liver IRI. These reveal a novel insight of neuropeptide PACAP in combating liver IRI in clinical patients