Modulation of the phosphoinositide 3-kinase signaling pathway alters host response to sepsis, inflammation, and ischemia/reperfusion injury

Different types of cell death and their interactions in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion (I/R) injury is a multifaceted process observed in patients with coronary artery disease when blood flow is restored to the heart tissue following ischemia-induced damage. Cardiomyocyte cell death, particularly through apoptosis, necroptosis, autophagy, pyroptosis, and ferroptosis, is pivotal in myocardial I/R injury. Preventing cell death during the process of I/R is vital for improving ischemic cardiomyopathy. These multiple forms of cell death can occur simultaneously, interact with each other, and contribute to the complexity of myocardial I/R injury. In this review, we aim to provide a comprehensive summary of the key molecular mechanisms and regulatory patterns involved in these five types of cell death in myocardial I/R injury. We will also discuss the crosstalk and intricate interactions among these mechanisms, highlighting the interplay between different types of cell death. Furthermore, we will explore specific molecules or targets that participate in different cell death pathways and elucidate their mechanisms of action. It is important to note that manipulating the molecules or targets involved in distinct cell death processes may have a significant impact on reducing myocardial I/R injury. By enhancing researchers' understanding of the mechanisms and interactions among different types of cell death in myocardial I/R injury, this review aims to pave the way for the development of novel interventions for cardio-protection in patients affected by myocardial I/R injury.

Predicting transcriptional responses to novel chemical perturbations using deep generative model for drug discovery

Understanding transcriptional responses to chemical perturbations is central to drug discovery, but exhaustive experimental screening of disease-compound combinations is unfeasible. To overcome this limitation, here we introduce PRnet, a perturbation-conditioned deep generative model that predicts transcriptional responses to novel chemical perturbations that have never experimentally perturbed at bulk and single-cell levels. Evaluations indicate that PRnet outperforms alternative methods in predicting responses across novel compounds, pathways, and cell lines. PRnet enables gene-level response interpretation and in-silico drug screening for diseases based on gene signatures. PRnet further identifies and experimentally validates novel compound candidates against small cell lung cancer and colorectal cancer. Lastly, PRnet generates a large-scale integration atlas of perturbation profiles, covering 88 cell lines, 52 tissues, and various compound libraries. PRnet provides a robust and scalable candidate recommendation workflow and successfully recommends drug candidates for 233 diseases. Overall, PRnet is an effective and valuable tool for gene-based therapeutics screening.

Sulfate-Reducing Bacteria Induce Pro-Inflammatory TNF-α and iNOS via PI3K/Akt Pathway in a TLR 2-Dependent Manner

Desulfovibrio, resident gut sulfate-reducing bacteria (SRB), are found to overgrow in diseases such as inflammatory bowel disease and Parkinson's disease. They activate a pro-inflammatory response, suggesting that Desulfovibrio may play a causal role in inflammation. Class I phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway regulates key events in the inflammatory response to infection. Dysfunctional PI3K/Akt signaling is linked to numerous diseases. Bacterial-induced PI3K/Akt pathway may be activated downstream of toll-like receptor (TLR) signaling. Here, we tested the hypothesis that Desulfovibrio vulgaris (DSV) may induce tumor necrosis factor alpha (TNF-α) and inducible nitric oxide synthase (iNOS) expression via PI3K/Akt in a TLR 2-dependent manner. RAW 264.7 macrophages were infected with DSV, and protein expression of p-Akt, p-p70S6K, p-NF-κB, p-IkB, TNF-α, and iNOS was measured. We found that DSV induced these proteins in a time-dependent manner. Heat-killed and live DSV, but not bacterial culture supernatant or a probiotic Lactobacillus plantarum, significantly caused PI3K/AKT/TNF/iNOS activation. LY294002, a PI3K/Akt signaling inhibitor, and TL2-C29, a TLR 2 antagonist, inhibited DSV-induced PI3K/AKT pathway. Thus, DSV induces pro-inflammatory TNF-α and iNOS via PI3K/Akt pathway in a TLR 2-dependent manner. Taken together, our study identifies a novel mechanism by which SRB such as Desulfovibrio may trigger inflammation in diseases associated with SRB overgrowth.

Trilobatin ameliorates dextran sulfate sodium-induced ulcerative colitis in mice via the NF-κB pathway and alterations in gut microbiota

OBJECTIVE

This study aimed to evaluate the effects of trilobatin (TLB) on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice and further explore the underlying mechanisms from the perspectives of signaling pathway and gut microbiota.

METHODS

A mouse model of UC was established using DSS. Trilobatin was administered via oral gavage. Disease severity was assessed based on body weight, disease activity index (DAI), colon length, histological detection, inflammation markers, and colonic mucosal barrier damage. Alternations in the NF-κB and PI3K/Akt pathways were detected by marker proteins. High-throughput 16S rRNA sequencing was performed to investigate the gut microbiota of mice.

RESULTS

In the DSS-induced UC mice, TLB (30 μg/g) treatment significantly increased the body weight, reduced the DAI score, alleviated colon length shortening, improved histopathological changes in colon tissue, inhibited the secretion and expression of inflammation factors (TNF-α, IL-1β, and IL-6), and increased the expression of tight-junction proteins (ZO-1 and occludin). Furthermore, TLB (30 μg/g) treatment significantly suppressed the activation of NF-κB pathway and altered the composition and diversity of the gut microbiota, as observed in the variations of the relative abundances of Proteobacteria, Actinobacteriota, and Bacteroidota, in UC mice.

CONCLUSION

TLB effectively alleviates DSS-induced UC in mice. Regulation of the NF-κB pathway and gut microbiota contributes to TLB-mediated therapeutic effects. Our study not only identified a novel drug candidate for the treatment of UC, but also enhanced our understanding of the biological functions of TLB.

Glucans: A Therapeutic Alternative for Sepsis Treatment

Sepsis treatment is a challenging condition due to its complexity, which involves host inflammatory responses to a severe and potentially fatal infection, associated with organ dysfunction. The aim of this study was to analyze the scientific literature on the immunomodulatory effects of glucans in a murine model of systemic infection induced by cecal ligation and puncture. This study comprises an integrative literature review based on systematic steps, with searches carried out in the PubMed, ScienceDirect, Scopus, Web of Science, and Embase databases. In most studies, the main type of glucan investigated was β-glucan, at 50 mg/kg, and a reduction of inflammatory responses was identified, minimizing the occurrence of tissue damage leading to increased animal survival. Based on the data obtained and discussed in this review, glucans represent a promising biotechnological alternative to modulate the immune response and could potentially be used in the clinical management of septic individuals.

The Modulation of Phospho-Extracellular Signal-Regulated Kinase and Phospho-Protein Kinase B Signaling Pathways plus Activity of Macrophage-Stimulating Protein Contribute to the Protective Effect of Stachydrine on Acetaminophen-Induced Liver Injury

Stachydrine, a prominent bioactive alkaloid derived from Leonurus heterophyllus, is a significant herb in traditional medicine. It has been noted for its anti-inflammatory and antioxidant characteristics. Consequently, we conducted a study of its hepatoprotective effect and the fundamental mechanisms involved in acetaminophen (APAP)-induced liver injury, utilizing a mouse model. Mice were intraperitoneally administered a hepatotoxic dose of APAP (300 mg/kg). Thirty minutes after APAP administration, mice were treated with different concentrations of stachydrine (0, 2.5, 5, and 10 mg/kg). Animals were sacrificed 16 h after APAP injection for serum and liver tissue assays. APAP overdose significantly elevated the serum alanine transferase levels, hepatic pro-inflammatory cytokines, malondialdehyde activity, phospho-extracellular signal-regulated kinase (ERK), phospho-protein kinase B (AKT), and macrophage-stimulating protein expression. Stachydrine treatment significantly decreased these parameters in mice with APAP-induced liver damage. Our results suggest that stachydrine may be a promising beneficial target in the prevention of APAP-induced liver damage through attenuation of the inflammatory response, inhibition of the ERK and AKT pathways, and expression of macrophage-stimulating proteins.

The PI3K-Akt pathway is a multifaceted regulator of the macrophage response to diverse group B Streptococcus isolates

Group B Streptococcus (GBS), also known as Streptococcus agalactiae, is a common member of the microbial flora in healthy individuals. However, problems may arise when GBS-colonized mothers become pregnant. GBS may be transferred from a colonized mother to her newborn or developing fetus, which may result in complications such as miscarriage, pre-term birth, meningitis, pneumonia, or sepsis. Macrophages play an especially important role in the fetal and newborn response to GBS due to the limited development of the adaptive immune system early in life. The goal of this study was to expand what is currently known about how GBS manipulates macrophage cell signaling to evade the immune system and cause disease. To this end, we investigated whether the PI3K-Akt pathway was involved in several key aspects of the macrophage response to GBS. We explored whether certain GBS strains, such as sequence type (ST)-17 strains, rely on this pathway for the more rapid macrophage uptake they induce compared to other GBS strains. Our findings suggest that this pathway is, indeed, important for macrophage uptake of GBS. Consistent with these findings, we used immunofluorescence microscopy to demonstrate that more virulent strains of GBS induce more actin projections in macrophages than less virulent strains. Additionally, we explored whether PI3K-Akt signaling impacted the ability of GBS to survive within macrophages after phagocytosis and whether this pathway influenced the survival rate of macrophages themselves following GBS infection. The PI3K-Akt pathway was found to promote the survival of both macrophages and intracellular GBS following infection. We also observed that inhibition of the PI3K-Akt pathway significantly reduced GBS-mediated activation of NFκB, which is a key regulator of cell survival and inflammatory responses. Overall, these insights into strain-dependent GBS-mediated manipulation of the PI3K-Akt pathway and its downstream targets in infected macrophages may provide new insights for the development of diagnostic and therapeutic tools to combat severe GBS disease.

The role of PI3K/AKT signaling pathway in myocardial ischemia-reperfusion injury

Myocardial ischemia has a high incidence and mortality rate, and reperfusion is currently the standard intervention. However, reperfusion may lead to further myocardial damage, known as myocardial ischemia/reperfusion injury (MIRI). There are currently no effective clinical treatments for MIRI. The PI3K/Akt signaling pathway is involved in cardiovascular health and disease and plays an important role in reducing myocardial infarct size and restoring cardiac function after MIRI. Activation of the PI3K/Akt pathway provides myocardial protection through synergistic upregulation of antioxidant, anti-inflammatory, and autophagy activities and inhibition of mitochondrial dysfunction and cardiomyocyte apoptosis. Many studies have shown that PI3K/Akt has a significant protective effect against MIRI. Here, we reviewed the molecular regulation of PI3K/Akt in MIRI and summarized the molecular mechanism by which PI3K/Akt affects MIRI, the effects of ischemic preconditioning and ischemic postconditioning, and the role of related drugs or activators targeting PI3K/Akt in MIRI, providing novel insights for the formulation of myocardial protection strategies. This review provides evidence of the role of PI3K/Akt activation in MIRI and supports its use as a therapeutic target.

The citrus flavonoid "Nobiletin" impedes STZ-induced Alzheimer's disease in a mouse model through regulating autophagy mastered by SIRT1/FoxO3a mechanism

The prominence of autophagy in the modulation of neurodegenerative disorders has sparked interest to investigate its stimulation in Alzheimer's disease (AD). Nobiletin possesses several bioactivities such as anti-inflammation, antioxidation, and neuroprotection. Consequently, the study's aim was to inspect the possible neurotherapeutic impact of Nobiletin in damping AD through autophagy regulation. Mice were randomly assigned into: Group I which received DMSO, Groups II, III, and IV obtained STZ (3 mg/kg) intracerebroventricularly once with Nobiletin (50 mg/kg/day; i.p.) in Group III and Nobiletin with EX-527 (2 mg/kg, i.p.) in Group IV. Interestingly, Nobiletin ameliorated STZ-induced AD through enhancing the motor performance and repressing memory defects. Moreover, Nobiletin de-escalated hippocampal acetylcholinesterase (AChE) activity and enhanced acetylcholine level while halting BACE1 and amyloid-β levels. Meanwhile, Nobiletin stimulated the autophagy process through activating the SIRT1/FoxO3a, LC3B-II, and ATG7 pathway. Additionally, Nobiletin inhibited Akt pathway and controlled the level of NF-κB and TNF-α. Nobiletin amended the oxidative stress through enhancing GSH and cutting down MDA levels. However, EX527, SIRT1 inhibitor, counteracted the neurotherapeutic effects of Nobiletin. Therefore, the present study provides a strong verification for the therapeutic influence of Nobiletin in AD. This outcome may be assigned to autophagy stimulation through SIRT1/FoxO3a, inhibiting AChE activity, reducing neuroinflammation and oxidative stress.

Inhibition of the NLRP3 Inflammasome Activation/Assembly through the Activation of the PI3K Pathway by Naloxone Protects Neural Stem Cells from Ischemic Condition

Naloxone is a well-known opioid antagonist and has been suggested to have neuroprotective effects in cerebral ischemia. We investigated whether naloxone exhibits anti-inflammatory and neuroprotective effects in neural stem cells (NSCs) injured by oxygen-glucose deprivation (OGD), whether it affects the NOD-like receptor protein 3 (NLRP3) inflammasome activation/assembly, and whether the role of the phosphatidylinositol 3-kinase (PI3K) pathway is important in the control of NLRP3 inflammasome activation/assembly by naloxone. Primary cultured NSCs were subjected to OGD and treated with different concentrations of naloxone. Cell viability, proliferation, and the intracellular signaling proteins associated with the PI3K pathway and NLRP3 inflammasome activation/assembly were evaluated in OGD-injured NSCs. OGD significantly reduced survival, proliferation, and migration and increased apoptosis of NSCs. However, treatment with naloxone significantly restored survival, proliferation, and migration and decreased apoptosis of NSCs. Moreover, OGD markedly increased NLRP3 inflammasome activation/assembly and cleaved caspase-1 and interleukin-1β levels in NSCs, but naloxone significantly attenuated these effects. These neuroprotective and anti-inflammatory effects of naloxone were eliminated when cells were treated with PI3K inhibitors. Our results suggest that NLRP3 inflammasome is a potential therapeutic target and that naloxone reduces ischemic injury in NSCs by inhibiting NLRP3 inflammasome activation/assembly mediated by the activation of the PI3K signaling pathway.

Cardioprotective effect of epigallocatechin gallate in myocardial ischemia/reperfusion injury and myocardial infarction: a meta-analysis in preclinical animal studies

This meta-analysis aims to determine the efficacy of Epigallocatechin gallate (EGCG) in the treatment of myocardial ischemia-reperfusion injury (MIRI) and summarize the mechanisms involved. Literature from six databases including Web of Science, PubMed, Embase, China National Knowledge Infrastructure (CNKI), Wan-Fang database, and VIP database (VIP) were systematically searched. All the analysis were conducted by R. Twenty-five eligible studies involving 443 animals were included in this meta-analysis. The results indicated that compared to controls, EGCG exerts a cardioprotective effect by reducing myocardial infarct size (SMD = -4.06; 95% CI: -5.17, -2.94; P < 0.01; I2 = 77%). The funnel plot revealed publication bias. Moreover, EGCG significantly improves cardiac function, serum myocardial injury enzyme, and oxidative stress levels in MIRI animal models. This meta-analysis demonstrates that EGCG exhibits therapeutic promise in animal models of MIRI. However, further validation is still needed in large animal models and large clinical studies.

Pinellia ternata lectin induces inflammation through TLR4 receptor and mediates PI3K/Akt/mTOR axis to regulate NF-κB signaling pathway

Pinellia ternata, a widely used traditional Chinese medicine, contains a strong mucosal irritant that is connected with Pinellia ternata lectin (PTL) in its tubers. The purpose of this study was to explore the mechanisms by which PTL induces inflammation. We found that in RAW264.7 cells, PTL activated the PI3K/Akt/mTOR and NF-κB pathways, which resulted in the release of proinflammatory cytokines. Flow cytometry and laser confocal microscopy analysis showed that FITC-labeled PTL bound to the macrophages' surface. Based on kinetic analyses and protein-protein docking simulations, PTL was shown to bind toll-like receptor 4 (TLR4).it was demonstrated that PTL binds highly to Toll-like receptor 4 (TLR4). TLR4 knock-down or knockout resulted in a decrease in both cytokine release and PI3K/Akt/mTOR and NF-κB pathway activation in PTL-stimulated macrophages or mice. RNA-seq analysis showed that genes involved in the PI3K/Akt/mTOR signaling pathway were strongly upregulated in response to PTL stimulation, confirming that the PI3K/Akt/mTOR pathway is linked to the inflammatory effect of PTL in RAW264.7 cells. These findings reveal that PTL can mediate inflammation through TLR4 and activating the PI3K/Akt/mTOR to regulate NF-κB signaling pathways.

Panax ginseng against myocardial ischemia/reperfusion injury: A review of preclinical evidence and potential mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng C. A. Meyer (P. ginseng) is effective in the prevention and treatment of myocardial ischemia-reperfusion (I/R) injury. The mechanism by which P. ginseng exerts cardioprotective effects is complex. P. ginseng contains many pharmacologically active ingredients, such as molecular glycosides, polyphenols, and polysaccharides. P. ginseng and each of its active components can potentially act against myocardial I/R injury. Myocardial I/R was originally a treatment for myocardial ischemia, but it also induced irreversible damage, including oxygen-containing free radicals, calcium overload, energy metabolism disorder, mitochondrial dysfunction, inflammation, microvascular injury, autophagy, and apoptosis.

AIM OF THE STUDY

This study aimed to clarify the protective effects of P. ginseng and its active ingredients against myocardial I/R injury, so as to provide experimental evidence and new insights for the research and application of P. ginseng in the field of myocardial I/R injury.

MATERIALS AND METHODS

This review was based on a search of PubMed, NCBI, Embase, and Web of Science databases from their inception to February 21, 2022, using terms such as "ginseng," "ginsenosides," and "myocardial reperfusion injury." In this review, we first summarized the active ingredients of P. ginseng, including ginsenosides, ginseng polysaccharides, and phytosterols, as well as the pathophysiological mechanisms of myocardial I/R injury. Importantly, preclinical models with myocardial I/R injury and potential mechanisms of these active ingredients of P. ginseng for the prevention and treatment of myocardial disorders were generally summarized.

RESULTS

P. ginseng and its active components can regulate oxidative stress related proteins, inflammatory cytokines, and apoptosis factors, while protecting the myocardium and preventing myocardial I/R injury. Therefore, P. ginseng can play a role in the prevention and treatment of myocardial I/R injury.

CONCLUSIONS

P. ginseng has a certain curative effect on myocardial I/R injury. It can prevent and treat myocardial I/R injury in several ways. When ginseng exerts its effects, should be based on the theory of traditional Chinese medicine and with the help of modern medicine; the clinical efficacy of P. ginseng in preventing and treating myocardial I/R injury can be improved.

Dexmedetomidine attenuates renal ischemia-reperfusion injury through activating PI3K/Akt-eNOS signaling via α2 adrenoreceptors in renal microvascular endothelial cells

Renal microvascular endothelial cells (RMECs), which are closely related to regulation of vascular reactivity and modulation of inflammation, play a crucial role in the process of renal ischemia and reperfusion (I/R) injury. Previous studies have reported the protective effects of dexmedetomidine (DEX) against renal I/R injury, but little is known about the role of DEX on RMECs. This study aimed to investigate whether DEX alleviated renal I/R injury via acting on the RMECs. Mice underwent bilateral renal artery clamping for 45 min followed by reperfusion for 48 h, and the cultured neonatal mice RMECs were subjected to hypoxia for 1 h followed by reoxygenation (H/R) for 24 h. The results suggest that DEX alleviated renal I/R injury in vivo and improved cell viability of RMECs during H/R injury in vitro. Gene sequencing revealed that the PI3K/Akt was the top enriched signaling pathway and the endothelial cells were widely involved in renal I/R injury. DEX activated phosphorylation of PI3K and Akt, increased eNOS expression, and attenuated inflammatory responses. In addition, the results confirmed the distribution of α₂ adrenoreceptor (α₂ -AR) in RMECs. Furthermore, the protective effects of DEX against renal I/R injury were abolished by α₂ -AR antagonist (atipamezole), which was partly reversed by the PI3K agonist (740 Y-P). These findings indicated that DEX protects against renal I/R injury by activating the PI3K/Akt-eNOS pathway and inhibiting inflammation responses via α₂ -AR in RMECs.

Network pharmacology analysis and experimental validation to explore the mechanism of Shenlian extract on myocardial ischemia

ETHNOPHARMACOLOGICAL RELEVANCE

Shenlian extract (SL), extracted from Salvia miltiorrhiza Bunge and Andrographis paniculata (Burm. f.) Nees, has been proved to be effective in the prevention and treatment of atherosclerosis. Recently, we have partially elucidated the mechanisms involved in the therapeutic effects of SL on myocardial ischemia (MI). However, the underlying mechanisms remain largely unclear.

AIM OF THE STUDY

This study aims to explore the potential molecular mechanism of SL on MI on the basis of network pharmacology.

MATERIALS AND METHODS

First, the main active ingredients of SL were screened in the Traditional Chinese Medicine Integrated Database, and the MI-associated targets were collected from the DisGeNET database. Then, we used compound-target and target-pathway networks to uncover the therapeutic mechanisms of SL. On the basis of network pharmacology analysis results, we assessed the effects of SL in MI rat model and oxygen glucose deprivation model of H9c2 cells and validated the possible molecular mechanisms of SL on myocardial injury in vivo and in vitro.

RESULTS

The network pharmacology results showed that 37 potential targets were recognized, including TNF-α, Bcl-2, STAT3, PI3K and MMP2. These results revealed that the possible targets of SL were involved in the regulation of inflammation and apoptosis signaling pathway. Then, in vivo experiments indicated that SL significantly reduced the myocardial infarction size of MI rats. Serum CK-MB, cTnT, CK, LDH, and AST levels were significantly decreased by SL (P < 0.05 or P < 0.01). In vitro, SL significantly increased H9c2 cell viability. The levels of inflammation factors including TNF-α and MMP2 were significantly decreased by SL (P < 0.05 or P < 0.01). TUNEL and Annexin V/propidium iodide assays indicated that SL could significantly decrease the cell apoptotic rate in vivo and in vitro (P < 0.05 or P < 0.01). The remarkable upregulation of anti-apoptotic Bcl-2 and downregulation of pro-apoptotic Bax protein level further confirmed this result. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the PI3K-AKT and JAK2-STAT3 pathways were significantly enriched in SL. Compared with the model group, SL treatment significantly activated the PI3K-AKT and JAK2-STAT3 pathways in vivo and in vitro according to Western blot analyses.

CONCLUSION

SL could protect the myocardium from MI injury. The underlying mechanism may be related to the reduction of inflammation and apoptosis by activating the PI3K/AKT and JAK2/STAT3 pathways.

Innate Immune Memory and the Host Response to Infection

Unlike the adaptive immune system, the innate immune system has classically been characterized as being devoid of memory functions. However, recent research shows that innate myeloid and lymphoid cells have the ability to retain memory of prior pathogen exposure and become primed to elicit a robust, broad-spectrum response to subsequent infection. This phenomenon has been termed innate immune memory or trained immunity. Innate immune memory is induced via activation of pattern recognition receptors and the actions of cytokines on hematopoietic progenitors and stem cells in bone marrow and innate leukocytes in the periphery. The trained phenotype is induced and sustained via epigenetic modifications that reprogram transcriptional patterns and metabolism. These modifications augment antimicrobial functions, such as leukocyte expansion, chemotaxis, phagocytosis, and microbial killing, to facilitate an augmented host response to infection. Alternatively, innate immune memory may contribute to the pathogenesis of chronic diseases, such as atherosclerosis and Alzheimer's disease.

Phosphoinositide-3-Kinase/Akt-Endothelial Nitric Oxide Synthase Signaling Pathway Mediates the Neuroprotective Effect of Sevoflurane Postconditioning in a Rat Model of Hemorrhagic Shock and Resuscitation

BACKGROUND

Although extensive reports have demonstrated the neuroprotection of sevoflurane postconditioning in cases of focal and global cerebral ischemia/reperfusion, the underlying mechanisms are not completely elucidated. This study investigated whether this effect is related to endothelial nitric oxide synthase (eNOS) and mediated by the phosphoinositide-3-kinase pathway in a rat model of hemorrhagic shock and resuscitation.

METHODS

Adult male Sprague Dawley rats were subjected to hemorrhagic shock for 60 minutes and then resuscitation for 30 minutes in experimental groups. Sevoflurane postconditioning was performed at the beginning of resuscitation to completion. At 24 hours after resuscitation, the brain infarct volume was evaluated by 2,3,5-triphenyltetrazolium chloride staining. The neuronal morphological changes and apoptosis were determined by hematoxylin and eosin staining and immunohistochemistry analysis, respectively. The activity of phosphorylated Akt and eNOS was evaluated by Western blot analysis.

RESULTS

Brain injuries such as the cerebral infarct volume and pathological neuronal changes as well as cell apoptosis were observed in the hippocampus after hemorrhagic shock and resuscitation. Postconditioning with 2.4% sevoflurane significantly attenuated brain injuries. Wortmannin prevented the improvements of neuronal characteristics elicited by sevoflurane postconditioning as well as the hyperactivity of eNOS and phosphorylated Akt.

CONCLUSIONS

Sevoflurane postconditioning could attenuate brain injury induced by hemorrhagic shock and resuscitation, and this neuroprotective effect may be partly by upregulation of eNOS through the phosphoinositide-3-kinase/Akt signaling pathway.

Epoxyeicosatrienoic acids prevent cardiomyocytes against sepsis by A2AR-induced activation of PI3K and PPARγ

Although epoxyeicosatrienoic acids (EETs) have multiple protective effects against different diseases, whether they can improve the pathogenesis of lipopolysaccharide (LPS)-induced septic cardiac dysfunction remains unknown. We investigated the effects of EETs on the LPS-induced inflammatory response in myocardial dysfunction mice and H9c2 cardiac myocytes. Cardiac-specific CYP2J2 transgenic mice (Tr) showed improved cardiac function and reduced inflammation response after administration with LPS, while the protective effects were not observed in A_2A adenosine receptor (A_2AR/ADORA2A)-deficient mice (knockout/KO). In vitro, EETs prevented LPS-induced inflammation and apoptosis in the cardiomyocytes via A_2AR activation. Moreover, ZM241385 (A_2AR inhibitor) attenuated the cardioprotective properties of EETs. Further investigation demonstrated that A_2AR signal pathway activation partly regulated phosphatidylinositol 3-kinase (PI3K) and peroxisome proliferator-activated receptor-γ (PPARγ) expression. This is the first report on EETs exerting cardioprotective effects against LPS-induced cardiomyocyte injury via A_2AR activation.

Astragalus saponins improves stroke by promoting the proliferation of neural stem cells through phosphorylation of Akt

ETHNOPHARMACOLOGICAL RELEVANCE

As one of major components of Buyang Huanwu decoction, Astragali Radix is broadly used for stroke treatment. Astragalus saponins (AST), the main active compound from Astragali Radix has the potentials for neuroprotection and improving spatial memory without clear pharmacological mechanism.

AIM OF THE STUDY

The aim of this study was to investigate that pretreatment of AST is beneficial to protect against focal ischemic stroke in mouse model and its related underlying mechanism.

MATERIALS AND METHODS

The neurological and motor function of MCAO mice were assessed by TTC staining and CatWalk gait analysis. The effect of AST on proliferation of NSCs was showed by the expression of Ki67 of MCAO mice and the number and size of primary neurospheres cultured from adult SVZ. The intersection of stroke-related targets, neurogenesis targets and drug-related targets were identified by the online website (https://www.omicstudio.cn/index). Then GO functional annotation and KEGG pathway enrichment analysis were performed. Candidate target Akt was confirmed to increase proliferation of cultured NSCs from adult SVZ by CCK8 assay and Western blot.

RESULTS

We found that with the prolongation of administration time, AST improved neurological and motor function of MCAO mice, by promoting the proliferation of NSCs both in vivo and in vitro. Then, the primary network among drug, genes and biological pathway was established by using compound-target-disease & function-pathway analysis of astragalus membranaceus. PI3K/Akt which plays a key role in cell proliferation was among the top 10 most significant GO terms from above three aspects. Further analysis using cultured NSCs from adult SVZ confirmed that AST, astragaloside I (A1) and astragaloside III (A3) increased the proliferation of NSCs through targeting Akt.

CONCLUSION

The present study elucidated that Astragalus saponins pretreatment could provide a protective effect on experimental stroke mainly by enhancing proliferation of NSCs through targeting Akt. The findings provided a basis for the development of novel strategies for the treatment of stroke.

Medicarpin Protects Cerebral Microvascular Endothelial Cells Against Oxygen-Glucose Deprivation/Reoxygenation-Induced Injury via the PI3K/Akt/FoxO Pathway: A Study of Network Pharmacology Analysis and Experimental Validation

Medicarpin, a pterocarpan class of naturally occurring phytoestrogen possesses various biological functions. However, the effect of medicarpin on oxygen-glucose deprivation-reoxygenation (OGD/R)-induced injury in human cerebral microvascular endothelial cells (HCMECs) remains largely unknown. Target genes of medicarpin were predicted from PharmMapper. Target genes of ischemic stroke were predicted from public databases GeneCards and DisGeNET. Kyoto Encyclopedia of Genes and Genomes pathway enrichment of the intersecting targets was analyzed via DAVID 6.8. Cell viability was evaluated using CCK-8 assay. Malondialdehyde content, superoxide dismutase activity, and glutathione level were detected using corresponding commercially available kits. Cell death was assessed by TUNEL assays. Expression of protein kinase B (Akt), phosphorylated-Akt, forkhead box protein O1, phosphorylated-FoxO1, FoxO3a, and phosphorylated-FoxO3a (p-FoxO3a) was detected by western blot analysis. The intersecting targets of medicarpin and ischemic stroke were significantly enriched in phosphatidylinositol 3-kinase (PI3K)/Akt and FoxO pathways. Medicarpina attenuated OGD/R-evoked viability inhibition, oxidative stress, and cell death in HCMECs. Additionally, medicarpin activated the PI3K/Akt and FoxO pathways in OGD/R-induced HCMECs. Inhibition of PI3K/Akt pathway abrogated the neuroprotective effect of medicarpin on OGD/R-induced injury and activation of FoxO pathway in HCMECs. In conclusion, medicarpin suppressed OGD/R-induced injury in HCMECs by activating PI3K/Akt/FoxO pathway.

Cardiac Shock Wave Therapy Improves Ventricular Function by Relieving Fibrosis Through PI3K/Akt Signaling Pathway: Evidence From a Rat Model of Post-infarction Heart Failure

Objection: Cumulative studies have identified the effectiveness of cardiac shock wave therapy (CSWT) in treating heart failure after acute myocardial infarction (AMI), but little have been discussed with regard to the beneficial effects of CSWT on anti-fibrosis along with the underlying mechanism. In this study, we investigated whether CSWT could reduce post-AMI fibrosis and further explored the molecular mechanism.

Methods: Rat heart failure (HF) models induced by ligating the left anterior descending coronary artery were established and validated by echocardiography. Eligible animals were randomly categorized into five groups: the sham group, the HF group, the HF + CSWT group, the HF + LY294002 group, and the HF + CSWT + LY294002 group. The cardiac weight, serum level of BNP, NT-pro BNP and echocardiography parameters were measured to assess cardiac function in different groups. Masson's trichrome staining was used to assess the proportions of the fibrotic area. The expression level of CD34, αSMA was measured by RT-PCR, Immunohistochemistry and Immunofluorescent analyses and the level of PI3K/Akt was quantified by Immunohistochemistry and Western blotting.

Results: The application of CSWT significantly improved cardiac function and reduced myocardial fibrosis and level of CD34 and αSMA, compared to the HF group. CSWT led to significant elevations of p-PI3K and p-Akt expression levels compared to that of the HF group and the inhibition of the PI3K/Akt pathway abolished the observed beneficial effects of CSWT.

Conclusion: CSWT can facilitate the alleviation of cardiac fibrosis induced by AMI through the activation of PI3K/Akt signaling pathway.

Toll-Like Receptor 4 Activation Prevents Rat Cardiac Fibroblast Death Induced by Simulated Ischemia/Reperfusion

Death of cardiac fibroblasts (CFs) by ischemia/reperfusion (I/R) has major implications for cardiac wound healing. In in vivo models of myocardial infarction, toll-like receptor 4 (TLR4) activation has been reported as a cardioprotector; however, it remains unknown whether TLR4 activation can prevent CF death triggered by simulated I/R (sI/R). In this study, we analyzed TLR4 activation in neonate CFs exposed to an in vitro model of sI/R and explored the participation of the pro-survival kinases Akt and ERK1/2. Simulated ischemia was performed in a free oxygen chamber in an ischemic medium, whereas reperfusion was carried out in normal culture conditions. Cell viability was analyzed by trypan blue exclusion and the MTT assay. Necrotic and apoptotic cell populations were evaluated by flow cytometry. Protein levels of phosphorylated forms of Akt and ERK1/2 were analyzed by Western blot. We showed that sI/R triggers CF death by necrosis and apoptosis. In CFs exposed only to simulated ischemia or only to sI/R, blockade of the TLR4 with TAK-242 further reduced cell viability and the activation of Akt and ERK1/2. Preconditioning with lipopolysaccharide (LPS) or treatment with LPS in ischemia or reperfusion was not protective. However, LPS incubation during both ischemia and reperfusion periods prevented CF viability loss induced by sI/R. Furthermore, LPS treatment reduced the sub-G1 population, but not necrosis of CFs exposed to sI/R. On the other hand, the protective effects exhibited by LPS were abolished when TLR4 was blocked and Akt and ERK1/2 were inhibited. In conclusion, our results suggest that TLR4 activation protects CFs from apoptosis induced by sI/R through the activation of Akt and ERK1/2 signaling pathways.

Therapeutic modulation of the phosphatidylinositol 3-kinases (PI3K) pathway in cerebral ischemic injury

The cerebral ischemic reperfusion injury may leads to morbidity and mortality in patients. phosphatidylinositol 3-kinase (PI3K) signaling pathway has been believed to work in association with its downstream targets, other receptors, and pathways that may offer antioxidant, anti-inflammatory, anti-apoptotic effects, neuroprotective role in neuronal excitotoxicity. This review elaborates the mechanistic interventions of the PI3K pathway in cerebral ischemic injury in context to nuclear factor erythroid 2-related factor 2 (Nrf2) regulation, Hypoxia-inducible factor 1 signaling (HIF-1), growth factors, Endothelial NOS (eNOS) proinflammatory cytokines, Erythropoietin (EPO), Phosphatase and tensin homologous protein of chromosome 10 gene (PTEN) signaling, NF-κB/Notch signaling, c-Jun N-terminal kinase (JNK) and Glycogen synthase kinase-3β (GSK-3β) signaling pathway. Evidences showing the activation of PI3K inhibits apoptotic pathway, which results in its neuroprotective effect in ischemic injury. Despite discussing the therapeutic role of the PI3K pathway in treating cerebral ischemic injury, the review also enlighten the selective modulation of PI3K pathway with activators and inhibitors which may provide promising results in clinical and preclinical settings.

Icariside II ameliorates myocardial ischemia and reperfusion injury by attenuating inflammation and apoptosis through the regulation of the PI3K/AKT signaling pathway

Icariside II (ICAII) is a bioflavonoid compound which has demonstrated anti-oxidative, anti-inflammatory and anti-apoptotic biological activities. However, to the best of our knowledge, whether ICAII can alleviate myocardial ischemia and reperfusion injury (MIRI) remains unknown. The aim of the present study was to determine whether ICAII exerted a protective effect on MIRI and to investigate the potential underlying mechanism of action. A rat MIRI model was established by ligation of the left anterior descending coronary artery for 30 min, followed by a 24 h reperfusion. Pretreatment with ICAII with or without a PI3K/AKT inhibitor was administered at the beginning of reperfusion. Morphological and histological analyses were detected using hematoxylin and eosin staining; the infarct size was measured using Evans blue and 2,3,5-triphenyltetrazolium chloride staining; and plasma levels of lactate dehydrogenase (LDH) and creatine kinase-myocardial band (CK-MB) were analyzed using commercialized assay kits. In addition, the cardiac function was evaluated by echocardiography and the levels of cardiomyocyte apoptosis were determined using a TUNEL staining. The protein expression levels of Bax, Bcl-2, cleaved caspase-3, interleukin-6, tumor necrosis factor-α, PI3K, phosphorylated (p)-PI3K, AKT and p-AKT were analyzed using western blotting analysis. ICAII significantly reduced the infarct size, decreased the release of LDH and CK-MB and improved the cardiac function induced by IR injury. Moreover, ICAII pretreatment significantly inhibited myocardial apoptosis and the inflammatory response. ICAII also upregulated the expression levels of p-PI3K and p-AKT. However, the protective effects of ICAII were abolished by an inhibitor (LY294002) of the PI3K/AKT signaling pathway. In conclusion, the findings of the present study suggested that ICAII may mitigate MIRI by activating the PI3K/AKT signaling pathway.

Dexmedetomidine Ameliorates Lung Injury Induced by Intestinal Ischemia/Reperfusion by Upregulating Cannabinoid Receptor 2, Followed by the Activation of the Phosphatidylinositol 3-Kinase/Akt Pathway

Intestinal ischemia/reperfusion (I/R) is a clinical emergency, which often causes lung injury with high morbidity and mortality. Although dexmedetomidine has been identified to have a protective effect on lung injury caused by intestinal I/R, its specific mechanism is still elucidated. In recent years, the cannabinoid (CB₂) receptor pathway has been found to be involved in I/R injury of some organs. In the current study, we investigated whether the CB₂ receptor pathway contributes to the protective effect of dexmedetomidine on the intestinal I/R-induced lung injury in rats. Dexmedetomidine treatment upregulated the expression of CB₂ receptor and suppressed the I/R-induced increases in lung injury scores, inflammatory cell infiltration, lung wet/dry ratio, MPO activity, MDA level, inflammatory cytokines, and caspase-3 expression while augmenting SOD activity and Bcl-2 expression, indicating attenuation of lung injury. Dexmedetomidine treatment also increased the expression of Akt. The protective effects of dexmedetomidine treatment were reversed by the CB₂ receptor antagonist AM630 or the PI3K inhibitor wortmannin. And the CB₂ receptor antagonist AM630 also downregulated the expression of Akt. Thus, our findings suggest that treatment with dexmedetomidine provides a protective role against lung injury caused by intestinal I/R in rats, possibly due to the upregulation of the CB₂ receptor, followed by the activation of the PI3K/Akt pathway.

The Effect of the Ultra-Marathon Run at a Distance of 100 Kilometers on the Concentration of Selected Adipokines in Adult Men

Pro-inflammatory adipokines have a multifunctional role in adipogenesis, angiogenesis, glucose homeostasis, and inflammation. The aim of the present study is to evaluate the effect of running a 100 km ultra-marathon on serum levels of two adipokines: resistin and chemerin. Fifteen male participants complete a medical questionnaire and their body composition is assessed. Serum resistin, chemerin, high sensitivity C-reactive protein (hs-CRP), glucose, and lactate levels are measured at baseline and post-race. During-race data on fluid and food consumption and energy expenditure are calculated. There is a higher (p < 0.001) post-race concentration of resistin and hs-CRP compared with resting values, with no change in chemerin levels. There is an inverse correlation of the change in resistin levels with post-run glucose values (r = 0.742, p < 0.001) and a positive correlation between changes in hs-CRP and energy expenditure (r = 0.782, p < 0.001). The present results show the impact of running an ultra-marathon on serum levels of pro-inflammatory markers released by adipose tissue. It is difficult to establish whether these results may be due to the stress of exercise, high energy expenditure or caloric deficit. However, we suggest that an addition of resistin to traditional pro-inflammatory markers (including CRP) may improve the assessment of inflammation in conditions of high-energy expenditure.

C1q/TNF-related protein 6 (CTRP6) attenuates renal ischaemia-reperfusion injury through the activation of PI3K/Akt signalling pathway

C1q/TNF-related protein 6 (CTRP6) is a member of the CTRP family that has been reported to exhibit a nephroprotective effect. However, the role of CTRP6 in renal ischaemia/reperfusion (I/R) injury (IRI) remains unclear. In the present study, we aimed to explore the protective effect of CTRP6 in renal IRI and the potential mechanism. We found that CTRP6 expression was markedly decreased in the kidneys of mice subjected to I/R and HK-2 cells in response to hypoxia/reoxygenation (H/R) stimulation. Recombinant CTRP6 protein protected against renal I/R injury by the reduction of blood urea nitrogen (BUN) and creatinine levels. The increased production of ROS and malondialdehyde (MDA), as well the decreased activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD) caused by H/R induction were mitigated by CTRP6 in HK-2 cells. The caspase-3 activity and apoptotic rate were both decreased in CTRP6-overexpressing HK-2 cells. In addition, we also found that knockdown of CTRP6 aggravated H/R-caused oxidative stress and cell apoptosis in HK-2 cells. Moreover, CTRP6 overexpression enhanced the H/R-stimulated activation of PI3K/Akt pathway in HK-2 cells. Inhibition of PI3K reversed the nephroprotective effects of CTRP6 in HK-2 cells. Taken together, CTRP6 exerted protective effects against H/R-caused oxidative injury in HK-2 cells via activating the PI3K/Akt pathway.

Downregulation of DLGAP1-Antisense RNA 1 Alleviates Vascular Endothelial Cell Injury Via Activation of the Phosphoinositide 3-kinase/Akt Pathway Results from an Acute Limb Ischemia Rat Model

OBJECTIVE

This study aimed to investigate the effect of long non-coding RNA (lncRNA) DLGAP1 antisense RNA 1 (DLGAP1-AS1) on vascular endothelial cell (VEC) injury via the phosphoinositide 3-kinase (PI3K)/Akt pathway in rat models of acute lower limb ischaemia-reperfusion (I/R).

METHODS

Differentially expressed lncRNAs related to I/R were screened using the gene expression omnibus database. Acute lower limb I/R models were induced in male Wistar rats, in which the regulatory mechanisms of DLGAP1-AS1 silencing were analysed after the treatment of small interfering RNA (siRNA) against DLGAP1-AS1 or an inhibitor of the PI3K/Akt pathway. The relationship between DLGAP1-AS1 and the PI3K/Akt pathway was analysed. The levels of tumour necrosis factor (TNF)-α and vascular cell adhesion molecule-1 (VCAM-1), as well as malondialdehyde (MDA) concentration and creatine kinase (CK) activity, were measured. The number of circulating endothelial cells (CECs) and apoptosis of VECs were identified.

RESULTS

Microarray based analysis indicated that DLGAP1-AS1 was highly expressed in I/R, which was further confirmed by detection of expression in rat models of acute lower limb I/R. Notably, the treatment of siRNA against DLGAP1-AS1 led to the activation of the PI3K/Akt pathway. In response to siRNA against DLGAP1-AS1, the levels of TNF-α and VCAM-1 were decreased, and MDA concentration and CK activity was downregulated. Reduced CEC numbers and suppressed VEC apoptosis were also observed.

CONCLUSION

DLGAP1-AS1 silencing could further suppress the oxidative stress, exert an anti-apoptosis effect, and reduce inflammatory reaction, whereby VEC injury is alleviated by activation of the PI3K/Akt pathway in rats with acute lower limb I/R.

Monophosphoryl lipid A induces protection against LPS in medullary thick ascending limb through induction of Tollip and negative regulation of IRAK-1

LPS inhibits HCO3- absorption in the medullary thick ascending limb (MTAL) through a Toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88)-extracellular signal-regulated kinase (ERK) pathway that is upregulated by sepsis. Pretreatment with the nontoxic immunomodulator monophosphoryl lipid A (MPLA) prevents inhibition by LPS through activation of a TLR4-TIR-domain-containing adaptor-inducing interferon-β (TRIF)-phosphatidylinositol 3-kinase (PI3K) pathway that prevents LPS-induced ERK activation. Here, we identified the molecular mechanisms that underlie the protective inhibitory interaction between the MPLA-PI3K and LPS-ERK pathways. Treatment of mouse MTALs with LPS in vitro increased phosphorylation of IL-1 receptor-associated kinase (IRAK)-1, a critical mediator of LPS signaling downstream of TLR4-MyD88. Activation of ERK by LPS was eliminated by a selective IRAK-1 inhibitor, establishing IRAK-1 as the upstream mediator of ERK activation. Pretreatment of MTALs with MPLA in vitro prevented LPS-induced IRAK-1 activation; this effect was dependent on PI3K. Treatment of MTALs with MPLA increased expression of Toll-interacting protein (Tollip), an inducible protein that negatively regulates LPS signaling by inhibiting IRAK-1. The MPLA-induced increase in Tollip protein level was prevented by PI3K inhibitors. In coimmunoprecipitation experiments, MPLA increased the amount of Tollip stably bound to IRAK-1, an interaction that inhibits IRAK-1 activation. These results support a mechanism whereby MPLA increases Tollip expression in the MTAL through a PI3K-dependent pathway. Tollip, in turn, inhibits LPS-induced TLR4 signaling by suppressing activation of IRAK-1, thereby preventing activation of ERK that inhibits HCO3- absorption. These studies show that MPLA induces reprogramming of MTAL cells that protects against LPS stimulation and identify IRAK-1 and Tollip as new therapeutic targets to prevent renal tubule dysfunction in response to infectious and inflammatory stimuli.

GPR 30 reduces myocardial infarct area and fibrosis in female ovariectomized mice by activating the PI3K/AKT pathway

AIMS

Estrogen plays an important role in cardioprotection. Animal experiments showed that the G-protein coupled estrogen receptor 30 (GPR30) specific agonist G1 could reduce post-ischemic dysfunction and inhibit cardiac fibroblast proliferation. However, the underlying mechanism of action is not clear. The current study tests the hypothesis that GPR30 reduces myocardial infarct area and fibrosis in female ovariectomized (OVX) mice by activating the PI3K/AKT pathway.

MAIN METHODS

In this study, we established a myocardial infarction (MI) animal model derived from OVX C57BL/6 female mice, and investigated the effect of G1 on cardiac function by echocardiography and Hemodynamics, morphology and expression of fibrosis-related and apoptosis-related proteins by Masson's trichrome and H&E, Immunofluorescence, Western blotting and TUNEL.

KEY FINDINGS

Combination with OVX significantly increased myocardial fibrosis and MI area compared to MI treatment alone, as determined by echocardiography and hemodynamics. Further addition of G1 changed the expression of apoptosis-related proteins, decreased the levels of tumor necrosis factor-α and interleukin-10, and reduced the degree of myocardial fibrosis and myocardial infarct area. Primary cultured cardiac fibroblasts (CFs) were subjected to hypoxia/serum deprivation (H/SD) simulating the in vivo ischemia model. When the PI3K/AKT pathway was inhibited by wortmanin in H/SD CFs, G1 failed to induce significant changes in the expression of apoptosis-related proteins.

SIGNIFICANCE

It suggested that GPR30 may improve cardiac function in female OVX mice by activating the PI3K/AKT pathway and reducing myocardial infarct size and fibrosis.

Phenylephrine Attenuated Sepsis-Induced Cardiac Inflammation and Mitochondrial Injury Through an Effect on the PI3K/Akt Signaling Pathway

OBJECTIVE

To investigate whether phenylephrine (PE) inhibits sepsis-induced cardiac dysfunction, cardiac inflammation, and mitochondrial injury through the PI3K/Akt signaling pathway.

METHODS

A rat model of sepsis was established by cecal ligation and puncture. PE and/or wortmannin (a PI3K inhibitor) were administered to investigate the role of PI3K/Akt signaling in mediating the effects of PE on inhibiting sepsis-induced cardiac dysfunction, cardiac inflammation, and mitochondrial injury. Hematoxylin-eosin staining, echocardiography, and Langendorff system were used to examine the myocardial injury and function. The concentrations of TNF-α and IL-6 were analyzed by enzyme-linked immunosorbent assay. Intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), myeloperoxidase, mitochondria-related fusion/fission proteins, and PI3K/Akt signaling pathway-associated proteins were analyzed by Western blotting.

RESULTS

PE improved the cardiac function and survival in septic rats. PE decreased TNF-α, IL-6, ICAM-1, VCAM-1, and myeloperoxidase contents in the myocardium of septic rats. Meanwhile, PE increased the fusion-related proteins and decreased the fission-related proteins in the myocardial mitochondria of septic rats. On the other hand, PE activated the PI3K/Akt signaling pathway in the cecal ligation and puncture-treated rats, and all the protective effects of PE were abolished by wortmannin.

CONCLUSIONS

PE attenuated sepsis-induced cardiac dysfunction, cardiac inflammation, and mitochondrial injury through the PI3K/Akt signaling pathway.

Hydrothermal processing of β-glucan from Aureobasidium pullulans produces a low molecular weight reagent that regulates inflammatory responses induced by TLR ligands

The Kururu no β-glu^® (KBG) is a commercial hydrothermal-treated Aureobasidium pullulans β-glucan produced by a unique hydrothermal process that results in high solubility of the β-glucan. In this study, we examined the biological activities of this reagent. RAW264.7 cells do not express Dictin-1 on the cell surface, but cells still respond to various pathogen molecular patterns. Lipopolysaccharide (LPS) induced nitrogen oxide (NO) synthesis and TNF-α production in RAW264.7 cells, and those were suppressed by KBG in a dose-dependent manner. The major signaling cell surface receptor respond to LPS is the TLR4/MD-2 complex. The UT12 antibody against to the TLR4/MD-2 complex mimics LPS function and induces cell responses. NO generation and TNF-α production were similarly induced in cells by stimulation with the antibody, but those were not suppressed by KBG. Cell responses induced by other TLR ligands, such as CPG (TLR9 ligand) and Pam3CSK4 (TLR1/TLR2 ligand), were also suppressed by KBG. Therefore, the target molecule for KBG is different from TLR receptors and Dictin-1. Although we also examined the suppressive activities of several other β-glucan products, comparable activities were not detected with other reagents. A unique hydrothermal process may produce the active reagent. Reprocessing KBG increased low molecular weight fractions, and suppressive activities were markedly enhanced. Therefore, low molecular weight fractions obtained by hydrothermal processing of KBG may result in potential reagents that control inflammation induced by various pathogens.

Insulin promotes macrophage phenotype transition through PI3K/Akt and PPAR-γ signaling during diabetic wound healing

Overactivation and persistent chronic inflammation are the major pathogenic characteristics of diabetic-impaired healing, and diabetic wound healing can be promoted by stimulating the transition of macrophage phenotype from pro-inflammatory (M1) to anti-inflammatory (M2). Our previous studies found that the application of insulin induced an advanced initiation and resolution of inflammatory response. To further explore the mechanism, we have investigated the effect of insulin on macrophage phenotype switch utilizing a diabetic rat model and a human monocytic THP-1 cell. We have utilized the high glucose (HG) and HG plus insulin to stimulate the M1 macrophages derived from lipopolysaccharide-treated THP-1 cells. We studied the secretion of inflammatory mediator and related signaling pathways by using western blot test, immunofluorescence, and Rac1 pull-down assay. We have found that the production of pro-inflammatory mediators, which thereafter induced macrophage polarization toward M1 phenotype, has been elevated due to consistent HG exposure. HG plus insulin stimulation, on the other hand, promoted anti-inflammatory effects. Experiments performed on diabetic burn wounds indicated that the insulin modulated macrophages transition from M1 to M2 phenotype. We found that PI3K/Akt/Rac-1 and PPAR-γ signaling pathways are involved in the anti-inflammatory effect of insulin. Insulin inhibited HG-induced activation of p38, NF-κB, and STAT1 transcriptional activity by activating Akt-Rac-1 signaling. Moreover, insulin performs anti-inflammatory effects through upregulation of PPAR-γ expression and induced P38-mediated dephosphorylation of PPAR-γ (Ser112). In conclusion, insulin downregulates inflammatory response, regulates M1 macrophage transition in response to HG, and thus improves chronic wound healing.

Role of PI3K/Akt/NF-κB and GSK-3β pathways in the rat model of cardiopulmonary bypass-related lung injury

BACKGROUND

Apoptosis is a cellular mechanism contributing to cardiac surgery using cardiopulmonary bypass (CPB)-induced lung injury. The ubiquitous PI3K/Akt pathway regulates proliferation, apoptosis and differentiation by controlling a broad range of target proteins including NF-κB and GSK-3β. The roles of the PI3K/Akt/NF-κB and PI3K/Akt/GSK-3β pathways in CPB-related lung injury are unclear.

METHODS

Seventy-two male Sprague-Dawley rats were assigned into sham, CPB, Wortmannin (Wtn) and insulin-like growth factor-I (IGF-I) groups (n = 18, each). Six subjects per group were evaluated at each of three time points: Prior to CPB (T1); opening of the left hilus pulmonis (T2); and 90 min after CPB (T3). Arterial blood specimens were obtained at each time point to test respiratory and oxygenation indices. Left lung tissues were processed for H&E and TUNEL staining. Western blot was employed to evaluate protein levels and activities of Akt, phospho-Akt (p-Akt), GSK-3β, phospho-GSK-3β (p-GSK-3β) and nuclear NF-κB.

RESULTS

Lung ischemia/reperfusion and CPB caused notable lung injury, as evidenced by lung functional decline and pathological deterioration, accompanied by increases in apoptosis and expression levels of p-Akt, p-GSK-3β and nuclear NF-κB in lungs (all P < 0.05 vs. Sham). At T3, Wtn-treated CPB subjects showed worsened lung function and pathological lung structures, as well as apoptosis in lungs (all P < 0.05 vs. CPB); additionally, Wtn inhibited Akt phosphorylation and slightly, but significantly increased expression of nuclear NF-κB (both P < 0.001 vs. CPB). Conversely, treatment of subjects with IGF-I increased Akt phosphorylation (P < 0.001 vs. CPB), inhibited expression of nuclear NF-κB (P = 0.008 vs. CPB), improved lung function and tissue morphology (both P < 0.05 vs. CPB), and reduced apoptosis in lungs (P < 0.001 vs. CPB). Neither Wtn nor IGF-I did alter GSK-3β phosphorylation levels (P =  0.836 and P =  0.669 vs. CPB, respectively).

CONCLUSION

The PI3K/Akt/NF-κB pathway played a role in CPB-related lung injury, possibly through mediating apoptosis in lungs. GSK-3β, a signaling effector that also participated in CPB-induced apoptosis in lungs, but was not regulated by the PI3K/Akt pathway in this context.

Hepatoprotective Effects of Corilagin Following Hemorrhagic Shock are Through Akt-Dependent Pathway

Corilagin, a component of Phyllanthus urinaria extract, possesses antioxidant, thrombolytic, antiatherogenic, and hepatoprotective properties, but the mechanism underlying these effects remains unclear. Previous studies showed that the Akt (protein kinase B) signaling pathway exerts anti-inflammatory and organ protective effects. The aim of this study was to investigate the mechanism of action of corilagin and determine whether these effects are mediated through the Akt-dependent pathway in a trauma-hemorrhagic shock-induced liver injury rodent model. Hemorrhagic shock was induced in male Sprague–Dawley rats; mean blood pressure was maintained at 35 mm Hg to 40 mm Hg for 90 min, followed by fluid resuscitation. During resuscitation, three doses of corilagin alone (1 mg/kg, 5 mg/kg, or 10 mg/kg, intravenously) were administered. Furthermore, a single dose of corilagin (5 mg/kg) with and without Wortmannin (1 mg/kg, PI3K inhibitor), Wortmannin alone, or vehicle was administered. Twenty-four hours after resuscitation, plasma alanine aminotransferase and aspartate aminotransferase concentration and hepatic parameters were measured. One-way ANOVA was used for statistical analysis. Hepatic myeloperoxidase activity and the concentrations of plasma alanine aminotransferase and aspartate aminotransferase, interleukin-6, tumor necrosis factor-α, intercellular adhesion molecule-1, and cytokine-induced neutrophil chemoattractant-1 (CINC-1) and CINC-3 increased following hemorrhagic shock. These parameters were significantly attenuated in corilagin-treated rats following hemorrhagic shock. Hepatic phospho-Akt expression was also higher in corilagin-treated rats than in vehicle-treated rats. The elevation of phospho-Akt was abolished by combined treatment with Wortmannin and corilagin. Our results suggest that corilagin exerts its protective effects on hemorrhagic shock-induced liver injury, at least, via the Akt-dependent pathway.

Analysis of long non-coding RNA expression profiles following focal cerebral ischemia in mice

Long noncoding RNAs (lncRNAs) have a variety of biological functions and play key roles in many diseases. However, the knowledge of lncRNA function during a stroke is limited. We analyzed the expression profiles of lncRNAs in the brain ischemic region of mice after a 45min middle cerebral artery occlusion (MCAO) with a 48h reperfusion. Gene ontology and pathway analysis were used to elucidate the potential functions of the differentially expressed mRNAs. A total of 255 lncRNAs (217 up-regulated and 38 down-regulated) and 894 mRNAs (870 up-regulated and 24 down-regulated) showed significantly altered expression in the ischemic brain compared to the sham controls (fold change ≫>2, P≪0.05). The gene ontology terms were mainly associated with neutrophil chemotaxis, positive regulation of inflammatory response, cell cycle, positive regulation of apoptotic process, and apoptotic process. The pathway analysis indicated that the mRNAs were mainly associated with inflammatory pathways. Additionally, the interactions between the differentially expressed lncRNAs and mRNAs are revealed by a dynamic lncRNA-mRNA network. Our findings provide an overview of aberrantly expressed lncRNAs in stroke and further broaden the understanding of stroke pathogenesis.

The Effects of Agaricus blazei Murill Polysaccharides on Cadmium-Induced Apoptosis and the TLR4 Signaling Pathway of Peripheral Blood Lymphocytes in Chicken

In this study, we investigated the effects of Agaricus blazei Murill polysaccharides (ABP) on cadmium (Cd)-induced apoptosis and the TLR4 signaling pathway of chicken peripheral blood lymphocytes (PBLs). Seven-day-old healthy chickens were randomly divided into four groups, and each group contained 20 males. The cadmium-supplemented diet group (Cd group) was fed daily with full feed that contained 140 mg cadmium chloride (CdCl₂)/kg and 0.2 mL saline. The A. blazei Murill polysaccharide diet group (ABP group) was fed daily with full feed with 0.2 mL ABP solution (30 mg/mL) by oral gavage. The cadmium-supplemented plus A. blazei Murill polysaccharide diet group (Cd + ABP group) was fed daily with full feed containing 140 mg CdCl₂/kg and 0.2 mL ABP solution (30 mg/mL) by gavage. The control group was fed daily with full feed with 0.2 mL saline per day. We measured the apoptosis rate and messenger RNA (mRNA) levels of apoptosis genes (caspase-3, Bax, and Bcl-2), the mRNA levels of TLR4 and TLR4 signaling pathway-related factors (MyD88, TRIF, NF-κB, and IRF3), the TLR4 protein expression, and the concentrations of inflammatory cytokines (IL-1β, IL-6, and TNF-α) in chicken PBLs. The results showed that the PBL apoptosis rate was significantly increased, the mRNA levels of caspase-3 and Bax were significantly increased, while that of Bcl-2 was significantly reduced. The Bax/Bcl-2 ratio was significantly increased in the Cd group at 20, 40, and 60 days after treatment compared with that in the control group. After treatment with ABP, the above changes were clearly suppressed. At the same time, ABP reduced the concentrations of IL-1β, IL-6, and TNF-α induced by Cd. We also found that ABP inhibited the TLR4 mRNA level and protein expression and inhibited the mRNA levels of MyD88, TRIF, NF-κB, and IRF3. The results demonstrated that Cd could induce apoptosis, activate the TLR4 signaling pathway, and induce the expression of inflammatory cytokines in chicken PBLs, and that the administration of ABP clearly inhibited Cd-induced effects on chicken PBLs.

The grapes and wrath: using resveratrol to treat the pathophysiology of hemorrhagic shock

Resveratrol, a naturally occurring polyphenol found in grapes, has been shown to reduce oxidative stress and inflammation in a variety of conditions. Recently, resveratrol has been investigated as a potential adjunct to resuscitation therapy for hemorrhagic shock-a condition characterized by tissue hypoxia, mitochondrial dysfunction, and inflammation. Although standard resuscitation restores tissue perfusion, it can exacerbate oxidative stress and organ damage. In rodent models of severe hemorrhagic shock, resveratrol mitigates reperfusion injury, preserves organ function, and improves survival. While many of these benefits can be attributed to its ability to activate sirtuin 1, resveratrol interacts with many targets that are relevant to ischemia-reperfusion. Here, we explore the probable mechanisms, potential benefits, and possible problems associated with administering resveratrol as an adjunct during resuscitation of hemorrhagic shock.

Neuroglobin Protects Rats from Sepsis-Associated Encephalopathy via a PI3K/Akt/Bax-Dependent Mechanism

Sepsis-associated encephalopathy (SAE) is a common complication of sepsis, and has no generally accepted treatment due to its complicated pathophysiology. Previously, we demonstrated the protective role of neuroglobin (Ngb) in SAE rats, but the exact mechanism has not been determined. To investigate the potential neuroprotective roles and mechanisms of Ngb, Sprague-Dawley rats were used. Overexpression of Ngb via intracerebroventricular injection with Ngb plasmids attenuated brain damage assessed by hematoxylin and eosin (HE) staining and neurological dysfunction assessed by Morris water maze test. Western blot analysis also showed that the phosphorylation of Akt increased and the protein level of Bax decreased. Furthermore, the protective effect can be abolished by PI3K/Akt pathway inhibitor LY294002. Our results demonstrate that Ngb can protect rats from SAE via a PI3K/Akt/Bax-dependent mechanism.

Monophosphoryl lipid A induces protection against LPS in medullary thick ascending limb through a TLR4-TRIF-PI3K signaling pathway

Monophosphoryl lipid A (MPLA) is a detoxified derivative of LPS that induces tolerance to LPS and augments host resistance to bacterial infections. Previously, we demonstrated that LPS inhibits [Formula: see text] absorption in the medullary thick ascending limb (MTAL) through a basolateral Toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88)-ERK pathway. Here we examined whether pretreatment with MPLA would attenuate LPS inhibition. MTALs from rats were perfused in vitro with MPLA (1 µg/ml) in bath and lumen or bath alone for 2 h, and then LPS was added to (and MPLA removed from) the bath solution. Pretreatment with MPLA eliminated LPS-induced inhibition of [Formula: see text] absorption. In MTALs pretreated with MPLA plus a phosphatidylinositol 3-kinase (PI3K) or Akt inhibitor, LPS decreased [Formula: see text] absorption. MPLA increased Akt phosphorylation in dissected MTALs. The Akt activation was eliminated by a PI3K inhibitor and in MTALs from TLR4^-/- or Toll/IL-1 receptor domain-containing adaptor-inducing IFN-β (TRIF)^-/- mice. The effect of MPLA to prevent LPS inhibition of [Formula: see text] absorption also was TRIF dependent. Pretreatment with MPLA prevented LPS-induced ERK activation; this effect was dependent on PI3K. MPLA alone had no effect on [Formula: see text] absorption, and MPLA pretreatment did not prevent ERK-mediated inhibition of [Formula: see text] absorption by aldosterone, consistent with MPLA's low toxicity profile. These results demonstrate that pretreatment with MPLA prevents the effect of LPS to inhibit [Formula: see text] absorption in the MTAL. This protective effect is mediated directly through MPLA stimulation of a TLR4-TRIF-PI3K-Akt pathway that prevents LPS-induced ERK activation. These studies identify detoxified TLR4-based immunomodulators as novel potential therapeutic agents to prevent or treat renal tubule dysfunction in response to bacterial infections.

The emerging role of Toll-like receptor 4 in myocardial inflammation

Toll-like receptors (TLRs) are a family of pattern recognition receptors involved in cardiovascular diseases. Notably, numerous studies have demonstrated that TLR4 activates the expression of several of pro-inflammatory cytokine genes that play pivotal roles in myocardial inflammation, particularly myocarditis, myocardial infarction, ischemia-reperfusion injury, and heart failure. In addition, TLR4 is an emerging target for anti-inflammatory therapies. Given the significance of TLR4, it would be useful to summarize the current literature on the molecular mechanisms and roles of TLR4 in myocardial inflammation. Thus, in this review, we first introduce the basic knowledge of the TLR4 gene and describe the activation and signaling pathways of TLR4 in myocardial inflammation. Moreover, we highlight the recent progress of research on the involvement of TLR4 in myocardial inflammation. The information reviewed here may be useful to further experimental research and to increase the potential of TLR4 as a therapeutic target.

4'-O-β-D-Glucosyl-5-O-Methylvisamminol, A Natural Histone H3 Phosphorylation Epigenetic Suppressor, Exerts a Neuroprotective Effect Through PI3K/Akt Signaling Pathway on Focal Cerebral Ischemia in Rats

BACKGROUND

A bursting inflammation has been observed that compromises neurologic function in patients who experience stroke. We sought to examine the neuroprotective efficacy of 4'-O-β-D-glucosyl-5-O-methylvisamminol (OGOMV), a novel histone H3 phosphorylation epigenetic suppressor) in a transient middle cerebral artery occlusion (tMCAO).

METHODS

A rodent tMCAO model was used. Administration with 400 μg/kg/day OGOMV was initiated 12 hours before (prevention) and 1 hour after animals were subjected to tMCAO (reversal). The cerebral cortex was harvested to examine protein kinase B (PI3D/Akt), 5-bromo-2'-deoxyuridine (Western blot), and caspases (reverse-transcription polymerase chain reaction). In addition, cerebrospinal fluid samples were collected to examine interleukin 1-β, interleukin-6, monocyte chemoattractant protein-1, and tumor necrosis factor-α (reverse-transcription polymerase chain reaction).

RESULTS

Cortical 5-bromo-2'-deoxyuridine and phospho-PI3D/Akt were reduced in tMCAO animals, compared with the healthy controls but increased in the OGOMV treatment and prevention groups. Activated cortical caspase-3,-6, and -9a as well as increased IL-1β and TNF-α levels were observed in the tMCAO animals (P < 0.05). Both prevention and treatment with OGOMV significantly reduced cleaved caspase-3 and -9a groups, but no significant change in caspase-6 was noted. Perifosine, an Akt inhibitor, was added to reduce the bioexpression of phospho-P13D/Akt, and Bcl-2 level and increased cleaved caspase-9a level in both OGOMV prevention and treatment tMCAO groups (P > 0.05).

CONCLUSION

Our study suggests that OGOMV could exert a neuroprotective effect by inhibiting the P13D/Akt protein, attenuating inflammation, and cleaved caspase-3- and -9a-related apoptosis. This study also lends credence to support the notion that the prevention of OGOMV could attenuate proinflammatory cytokine mRNA and late-onset caspases in tMCAO and merits further study.

Hepatoprotective effect of casodex after trauma hemorrhage in a rodent model

Casodex (bicalutamide), an androgen receptor antagonist, is used for the treatment of prostate cancer. Recent evidences show that Akt signaling pathway exerts organ-protective effects after injury. The aim of this study was to investigate whether Akt plays any role in the casodex-mediated attenuation of hepatic injury after trauma-hemorrhagic shock. Male Sprague-Dawley rats underwent trauma hemorrhage (mean blood pressure kept at approximately 35-40 mm Hg for 90 min), followed by fluid resuscitation. During resuscitation, a single dose of casodex (5 mg/kg, intravenous) with and without a phosphatidylinositol 3-kinase inhibitor wortmannin (1 mg/kg, intravenous), wortmannin or vehicle was administered. Plasma aspartate aminotransferase and alanine aminotransferase levels and various hepatic parameters were measured at 24 h after resuscitation. One-way analysis of variance and the Tukey test were used for statistical analysis. These results showed that trauma hemorrhage increased hepatic myeloperoxidase activity, interleukin 6 and intercellular adhesion molecule 1 levels, and plasma aspartate aminotransferase and alanine aminotransferase concentrations. In the trauma hemorrhage rats treated with casodex, these parameters were significantly improved. Casodex treatment also increased hepatic phospho-Akt expression compared with vehicle-treated trauma hemorrhaged rats. Coadministration of wortmannin with casodex abolished the casodex-induced advantageous effects on the aforementioned parameters and hepatic injury. Our results suggest that the protective effect of casodex administration on attenuation of hepatic injury after trauma hemorrhage, which is, at least in part, through Akt-dependent pathway.

Melatonin attenuates sepsis-induced cardiac dysfunction via a PI3K/Akt-dependent mechanism

Myocardial dysfunction is an important manifestation of sepsis. Previous studies suggest that melatonin is protective against sepsis. In addition, activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway has been reported to be beneficial in sepsis. However, the role of PI3K/Akt signaling in the protective effect of melatonin against sepsis-induced myocardial dysfunction remains unclear. Here, LY294002, a PI3K inhibitor, was used to investigate the role of PI3K/Akt signaling in mediating the effects of melatonin on sepsis-induced myocardial injury. Cecal ligation and puncture (CLP) surgery was used to establish a rat model of sepsis. Melatonin was administrated to rats intraperitoneally (30 mg/kg). The survival rate, measures of myocardial injury and cardiac performance, serum lactate dehydrogenase level, inflammatory cytokine levels, oxidative stress level, and the extent of myocardial apoptosis were assessed. The results suggest that melatonin administration after CLP surgery improved survival rates and cardiac function, attenuated myocardial injury and apoptosis, and decreased the serum lactate dehydrogenase level. Melatonin decreased the production of the inflammatory cytokines TNF-α, IL-1β, and HMGB1, increased anti-oxidant enzyme activity, and decreased the expression of markers of oxidative damage. Levels of phosphorylated Akt (p-Akt), unphosphorylated Akt (Akt), Bcl-2, and Bax were measured by Western blot. Melatonin increased p-Akt levels, which suggests Akt pathway activation. Melatonin induced higher Bcl-2 expression and lower Bax expression, suggesting inhibition of apoptosis. All protective effects of melatonin were abolished by LY294002, the PI3K inhibitor. In conclusion, our results demonstrate that melatonin mitigates myocardial injury in sepsis via PI3K/Akt signaling activation.

Sodium tanshinone IIA silate inhibits oxygen-glucose deprivation/recovery-induced cardiomyocyte apoptosis via suppression of the NF-κB/TNF-α pathway

BACKGROUND AND PURPOSE

Inhibition of apoptosis may attenuate the irreversible injury associated with reperfusion. In the current study, we focused on the cytoprotective effects and the underlying mechanism of sodium tanshinone IIA silate (STS) against damage induced by oxygen-glucose deprivation/recovery (OGD/R). in H9c2 cardiomyocytes and the underlying mechanisms.

EXPERIMENTAL APPROACH

We used a model of cardiac ischaemia/reperfusion, OGD/R in H9c2 cardiomyocytes, to assess the cardioprotective effects of STS. Apoptosis of cells was measured with Hoechst 33342-based fluorescence microscopy, and annexin V-FITC-based flow cytometry. Caspase-3 and caspase-8 activities and mitochondrial membrane potential were also measured using commercial kits. TNF-α in the cell culture supernatant fractions were measured with sandwich elisa, and protein levels assayed using Western blot.

KEY RESULTS

STS inhibited OGD/R-induced apoptosis by suppressing JNK-mediated activation of NF-κB, TNF-α expression, activation of caspase-3 and caspase-8 and the Bax/Bcl-2 ratio. Additionally, positive feedback between NF-κB and TNF-α and amplification of TNF-α were inhibited, suggesting that STS plays a protective role against apoptosis in cardiomyocytes, even upon activation of pro-inflammatory cytokines. Interestingly, the cytoprotective effects of STS on OGD/R-induced apoptosis and promotion of cell survival were attenuated after inhibition of PI3K.

CONCLUSION AND IMPLICATIONS

The inhibitory effects of STS on TNF-α and positive feedback signalling of the NF-κB/TNF-α pathways may play important roles in myocardial protection against ischaemia/reperfusion. These protective effects of STS are mediated by suppressing JNK activity through activation of the PI3K-Akt pathway.