PHLDA1 is a new therapeutic target of oxidative stress and ischemia reperfusion-induced myocardial injury

Egr1 promotes Nlrc4-dependent neuronal pyroptosis through phlda1 in an in-vitro model of intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a fatal brain injury, but the current treatments for it are inadequate to reduce the severity of secondary brain injury. Our study aims to explore the molecular mechanism of Egr1 and Phlda1 in regulating hemin-induced neuronal pyroptosis, and hope to provide novel therapeutic targets for ICH treatment. Mouse hippocampal neuron cells treated with hemin were used to simulate an in-vitro ICH model. Using qRT-PCR and western blot to evaluate mRNA and protein concentrations. MTT assay was utilized to assess cell viability. LDH levels were determined by lactate Dehydrogenase Activity Assay Kit. IL-1β and IL-18 levels were examined by ELISA. The interaction of Egr1 and Phlda1 promoter was evaluated using chromatin immunoprecipitation and dual-luciferase reporter assays. Egr1 and Phlda1 were both upregulated in HT22 cells following hemin treatment. Hemin treatment caused a significant reduction in HT22 cell viability, an increase in Nlrc4 and HT22 cell pyroptosis, and heightened inflammation. However, knocking down Egr1 neutralized hemin-induced effects on HT22 cells. Egr1 bound to the promoter of Phlda1 and transcriptionally activated Phlda1. Silencing Phlda1 significantly reduced Nlrc4-dependent neuronal pyroptosis. Conversely, overexpressing Phlda1 mitigated the inhibitory effects of Egr1 knockdown on Nlrc4 and neuronal pyroptosis during ICH. Egr1 enhanced neuronal pyroptosis mediated by Nlrc4 under ICH via transcriptionally activating Phlda1.

Aucubin protects against myocardial ischemia-reperfusion injury by regulating STAT3/NF-κB/HMGB-1 pathway

The main characteristics of the myocardial ischemia/reperfusion injury (MI/RI) are oxidative stress, apoptosis, and an inflammatory response. Aucubin (AU) is an iridoid glycoside that possesses various biological properties and has been discovered to demonstrate antioxidant and anti-inflammatory impacts in pathological processes, such as ischemia-reperfusion. The objective of this research was to investigate if AU treatment could mitigate myocardial inflammation and apoptosis caused by ischemia/reperfusion (I/R) in both laboratory and animal models, and to elucidate its underlying mechanism. By ligating the coronary artery on the left anterior descending side, a successful MI/RI rat model was created. Additionally, H9C2 cells were subjected to hypoxia/reoxygenation (H/R) in order to imitate the injury caused by ischemia/reperfusion (I/R). Furthermore, various concentrations of AU were administered to H9C2 cells or rats before H/R stimulation or myocardial I/R surgery, respectively. In vitro, the assessment was conducted on cardiac function, inflammatory markers, and myocardial pathology. In vivo, we examined the viability of cells, as well as factors related to apoptosis and oxidative stress. Furthermore, the presence of proteins belonging to the STAT3/NF-κB/HMGB1 signaling pathway was observed both in vivo and in vitro. AU effectively improved cardiomyocyte injury caused by H/R and myocardial injury caused by I/R. Furthermore, AU suppressed the production of reactive oxygen species and inflammatory molecules (TNF-alpha, IL-1β, and IL-6) and proteins associated with cell death (caspase-3 and Bax), while enhancing the levels of anti-inflammatory agents (IL-10) and the anti-apoptotic protein Bcl-2.AU mechanistically affected the phosphorylation of STAT3 at the Ser727 site and Tyr705 following H/R by modulating the signaling pathway involving signal transducer and activator of transcription 3 (STAT3)/nuclear factor-κB (NF-κB)/high mobility group box 1 (HMGB1), while also suppressing the nuclear translocation of NF-κB p65 and HMGB1 exonucleation. In conclusion, the use of AU treatment might offer protection against myocardial infarction and injury by reducing oxidative stress, suppressing apoptosis, and mitigating inflammation. The regulation of the STAT3/NF-κB/HMGB-1 pathway may contribute to this phenomenon by affecting STAT3 phosphorylation and controlling NF-κB and HMGB-1 translocation. Contributes to identifying possible objectives for myocardial ischemia/reperfusion damage.

Identification of Shared Signature Genes and Immune Microenvironment Subtypes for Heart Failure and Chronic Kidney Disease Based on Machine Learning

Background

A complex interrelationship exists between Heart Failure (HF) and chronic kidney disease (CKD). This study aims to clarify the molecular mechanisms of the organ-to-organ interplay between heart failure and CKD, as well as to identify extremely sensitive and specific biomarkers.

Methods

Differentially expressed tandem genes were identified from HF and CKD microarray datasets and enrichment analyses of tandem perturbation genes were performed to determine their biological functions. Machine learning algorithms are utilized to identify diagnostic biomarkers and evaluate the model by ROC curves. RT-PCR was employed to validate the accuracy of diagnostic biomarkers. Molecular subtypes were identified based on tandem gene expression profiling, and immune cell infiltration of different subtypes was examined. Finally, the ssGSEA score was used to build the ImmuneScore model and to assess the differentiation between subtypes using ROC curves.

Results

Thirty-three crosstalk genes were associated with inflammatory, immune and metabolism-related signaling pathways. The machine-learning algorithm identified 5 hub genes (PHLDA1, ATP1A1, IFIT2, HLTF, and MPP3) as the optimal shared diagnostic biomarkers. The expression levels of tandem genes were negatively correlated with left ventricular ejection fraction and glomerular filtration rate. The CIBERSORT results indicated the presence of severe immune dysregulation in patients with HF and CKD, which was further validated at the single-cell level. Consensus clustering classified HF and CKD patients into immune and metabolic subtypes. Twelve immune genes associated with immune subtypes were screened based on WGCNA analysis, and an ImmuneScore model was constructed for high and low risk. The model accurately predicted different molecular subtypes of HF or CKD.

Conclusion

Five crosstalk genes may serve as potential biomarkers for diagnosing HF and CKD and are involved in disease progression. Metabolite disorders causing activation of a large number of immune cells explain the common pathogenesis of HF and CKD.

FGF10 mitigates doxorubicin-induced myocardial toxicity in mice via activation of FGFR2b/PHLDA1/AKT axis

Doxorubicin is a common chemotherapeutic agent in clinic, but myocardial toxicity limits its use. Fibroblast growth factor (FGF) 10, a multifunctional paracrine growth factor, plays diverse roles in embryonic and postnatal heart development as well as in cardiac regeneration and repair. In this study we investigated the role of FGF10 as a potential modulator of doxorubicin-induced cardiac cytotoxicity and the underlying molecular mechanisms. Fgf10+/- mice and an inducible dominant negative FGFR2b transgenic mouse model (Rosa26rtTA; tet(O)sFgfr2b) were used to determine the effect of Fgf10 hypomorph or blocking of endogenous FGFR2b ligands activity on doxorubicin-induced myocardial injury. Acute myocardial injury was induced by a single injection of doxorubicin (25 mg/kg, i.p.). Then cardiac function was evaluated using echocardiography, and DNA damage, oxidative stress and apoptosis in cardiac tissue were assessed. We showed that doxorubicin treatment markedly decreased the expression of FGFR2b ligands including FGF10 in cardiac tissue of wild type mice, whereas Fgf10+/- mice exhibited a greater degree of oxidative stress, DNA damage and apoptosis as compared with the Fgf10+/+ control. Pre-treatment with recombinant FGF10 protein significantly attenuated doxorubicin-induced oxidative stress, DNA damage and apoptosis both in doxorubicin-treated mice and in doxorubicin-treated HL-1 cells and NRCMs. We demonstrated that FGF10 protected against doxorubicin-induced myocardial toxicity via activation of FGFR2/Pleckstrin homology-like domain family A member 1 (PHLDA1)/Akt axis. Overall, our results unveil a potent protective effect of FGF10 against doxorubicin-induced myocardial injury and identify FGFR2b/PHLDA1/Akt axis as a potential therapeutic target for patients receiving doxorubicin treatment.

PHLDA1 knockdown alleviates mitochondrial dysfunction and endoplasmic reticulum stress-induced neuronal apoptosis via activating PPARγ in cerebral ischemia-reperfusion injury

Mitochondrial dysfunction and endoplasmic reticulum (ER) stress occur in ischemic stroke. The disruption of these two organelles can directly lead to cell death through various signaling pathways. Thus, investigation of the associated molecular mechanisms in cerebral ischemia is a prerequisite for stroke treatment. Pleckstrin homology-like domain family A member 1 (PHLDA1) is a multifunctional protein that can modulate mitochondrial function and ER stress in cardiomyocyte and cancer cells. This work studied the role of PHLDA1 in cerebral ischemic/reperfusion (I/R) injury and explored the underlying mechanisms associated with mitochondrial functions and ER stress. Middle cerebral artery occlusion/reperfusion (MCAO/R)-treated mice and oxygen-glucose deprivation/reoxygenation (OGD/R)-stimulated neurons were used as I/R models in vivo and in vitro, respectively. PHLDA1 was upregulated in ischemic penumbra of MCAO/R-induced mice and OGD/R-exposed neurons. In vitro, PHLDA1 knockdown protected neurons from OGD/R-induced apoptosis. In vivo, PHLDA1 silencing facilitated functional recovery and reduced cerebral infarct volume. Mechanistically, PHLDA1 knockdown promoted PPARγ nuclear translocation, which may mediate the effects on reversion of mitochondrial functions and alleviation of ER stress. In summary, PHLDA1 knockdown alleviates neuronal ischemic injuries in mice. PPARγ activation and mitochondrial dysfunction and endoplasmic reticulum stress attenuation are involved in the underlying mechanisms.

TDAG51 deficiency attenuates dextran sulfate sodium-induced colitis in mice

Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is a group of chronic inflammatory diseases of the gastrointestinal tract. Although the multifactorial etiology of IBD pathogenesis is relatively well documented, the regulatory factors that confer a risk of IBD pathogenesis remain less explored. In this study, we report that T-cell death-associated gene 51 (TDAG51/PHLDA1) is a novel regulator of the development of dextran sulfate sodium (DSS)-induced colitis in mice. TDAG51 expression was elevated in the colon tissues of DSS-induced experimental colitis mice. TDAG51 deficiency protected mice against acute DSS-induced lethality and body weight changes and disease severity. DSS-induced structural damage and mucus secretion in colon tissues were significantly reduced in TDAG51-deficient mice compared with wild-type mice. We observed similar results in a DSS-induced chronic colitis mouse model. Finally, we showed that the production of inflammatory mediators, including proinflammatory enzymes, molecules and cytokines, was decreased in DSS-treated TDAG51-deficient mice compared with DSS-treated wild-type mice. Thus, we demonstrated that TDAG51 deficiency plays a protective role against DSS-induced colitis by decreasing the production of inflammatory mediators in mice. These findings suggest that TDAG51 is a novel regulator of the development of DSS-induced colitis and is a potential therapeutic target for IBD.

Loss of Pleckstrin homology like domain, family A, member 1 promotes type Ⅱ alveolar epithelial cell apoptosis in chronic obstructive pulmonary disease emphysematous phenotype via interaction with tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein epsilon

Emphysematous phenotype is the most important phenotypic component of chronic obstructive pulmonary disease and is associated with substantial morbidity and mortality. The current pharmaceutical treatments and therapeutic procedures do not reduce pulmonary damage in patients with emphysematous phenotype. Therefore, it is important to identify effector molecules that can be used as interfering targets in such patients. Apoptosis of type II alveolar epithelial cells plays a key role in the phenotypic formation. This study aimed to further explore the molecular mechanisms involved in this process. The number of type II alveolar epithelial cells was significantly reduced due to increased apoptosis in patients with emphysematous phenotype compared to those with non-emphysematous phenotype. Pleckstrin homology like domain, family A, member 1 (PHLDA1) was mainly distributed in type II alveolar epithelial cells in both groups but was markedly reduced in patients with emphysematous phenotype. Overexpression of PHLDA1 prevented cigarette smoke extract-stimulated apoptosis of type II alveolar epithelial cells, whereas its knockdown worsened the apoptosis. PHLDA1 binding ability to tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein epsilon (YWHAE) was weakened after exposure to cigarette smoke extract, with decreased PHLDA1 level lowering the abundance of YWHAE and attenuating the binding ability of YWHAE to p-Bad. These results demonstrate that considerable apoptosis of type II alveolar epithelial cells occurs in patients with emphysematous phenotype, and PHLDA1 may act as an effective antiapoptotic factor via YWHAE. Moreover, PHLDA1 may serve as a potential interfering target, providing insights into therapeutic strategies for emphysematous phenotype.

PHLDA1 promotes sevoflurane-induced pyroptosis of neuronal cells in developing rats through TRAF6-mediated activation of Rac1

Sevoflurane anesthesia induces neurocognitive impairment and pyroptosis in the developing brain. Pleckstrin homology-like domain, family A, member 1 (PHLDA1) was involved in neuronal apoptosis, oxidative stress and inflammation during ischemic stroke. The role of PHLDA1 in sevoflurane-induced pyroptosis in developing rats was investigated. Firstly, neonatal rats at day 7 was exposed to 2.0% sevoflurane for 6 h to induce neurotoxicity. Pathological analysis showed that sevoflurane anesthesia induced hippocampal injury and reduced the number of neurons. The expression of PHLDA1 was elevated in hippocampus of sevoflurane-treated rats. Secondly, sevoflurane anesthesia-treated neonatal rats were injected with adeno-associated virus serotype (AAV) to mediate knockdown of PHLDA1. Injection with AAV-shPHLDA1 ameliorated sevoflurane-induced hippocampal injury and neurocognitive impairment in rats. Moreover, knockdown of PHLDA1 increased the number of neurons in sevoflurane-treated rats. Silence of PHLDA1 suppressed neuronal apoptosis, and inhibited pyroptosis in sevoflurane-treated rats. Thirdly, PHLDA1 was also elevated in sevoflurane-treated primary neuronal cells. Loss of PHLDA1 also enhanced cell viability and suppressed pyroptosis of sevoflurane-treated primary neuronal cells. Lastly, silence of PHLDA1 reduced protein expression of TRAF6 and p-Rac1 in sevoflurane-treated rats and neuronal cells. Over-expression of TRAF6 attenuated PHLDA1 silence-induced increase of cell viability and decreased pyroptosis in neuronal cells. In conclusion, loss of PHLDA1 protected against sevoflurane-induced pyroptosis in developing rats through inhibition of TRAF6-mediated activation of Rac1.

Predicting potential biomarkers and immune infiltration characteristics in heart failure

BACKGROUND

Studies have demonstrated that immune cell activation and their infiltration in the myocardium can have adverse effects on the heart, contributing to the pathogenesis of heart failure (HF). The purpose of this study is used by bioinformatics analysis to determine the potential diagnostic markers of heart failure and establish an applicable model to predict the association between heart failure and immune cell infiltration.

METHODS

Firstly, gene expression profiles of dilated heart disease GSE3585 and GSE120895 were obtained in Gene Expression Omnibus (GEO) database. This study then selected differentially expressed genes (DEGs) in 54 patients with HF and 13 healthy controls. In this study, biomarkers were identified using Least Absolute Shrinkage and Selector Operation (LASSO) and Support Vector Machine-Recursive Feature Elimination (SVM-RFE). Additionally, we evaluated the prognostic discrimination performance by the receiver operating characteristic (ROC) curve. Cell type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) was used for analyzing immune cell infiltration in HF tissues. Lastly, immune biomarkers were correlated with each other.

RESULT

After 24 DEGs were analyzed using a combinatorial model of LASSO regression and SVM-RFE analysis, four key genes were obtained, namely NSG1, NPPB, PHLDA1, and SERPINE2.The area under the curve (AUC) of these four genes were greater than 0.8. Subsequently, using CIBERPORT, we also found that compared with normal people, the proportion of M1 macrophages and activated mast cells in heart failure tissues decreased. In addition, correlation analysis showed that NPPB, PHLDA1 and SERPINE2 were associated with immune cell infiltration.

CONCLUSION

NSG1, NPPB, PHLDA1 and SERPINE2 were identified as potential biomarkers of heart failure. It reveals the comprehensive role of relevant central genes in immune infiltration, which provides a new research idea for the treatment and early detection in heart failure.

Identification of candidate biomarkers and pathways associated with type 1 diabetes mellitus using bioinformatics analysis

Type 1 diabetes mellitus (T1DM) is a metabolic disorder for which the underlying molecular mechanisms remain largely unclear. This investigation aimed to elucidate essential candidate genes and pathways in T1DM by integrated bioinformatics analysis. In this study, differentially expressed genes (DEGs) were analyzed using DESeq2 of R package from GSE162689 of the Gene Expression Omnibus (GEO). Gene ontology (GO) enrichment analysis, REACTOME pathway enrichment analysis, and construction and analysis of protein–protein interaction (PPI) network, modules, miRNA-hub gene regulatory network and TF-hub gene regulatory network, and validation of hub genes were performed. A total of 952 DEGs (477 up regulated and 475 down regulated genes) were identified in T1DM. GO and REACTOME enrichment result results showed that DEGs mainly enriched in multicellular organism development, detection of stimulus, diseases of signal transduction by growth factor receptors and second messengers, and olfactory signaling pathway. The top hub genes such as MYC, EGFR, LNX1, YBX1, HSP90AA1, ESR1, FN1, TK1, ANLN and SMAD9 were screened out as the critical genes among the DEGs from the PPI network, modules, miRNA-hub gene regulatory network and TF-hub gene regulatory network. Receiver operating characteristic curve (ROC) analysis confirmed that these genes were significantly associated with T1DM. In conclusion, the identified DEGs, particularly the hub genes, strengthen the understanding of the advancement and progression of T1DM, and certain genes might be used as candidate target molecules to diagnose, monitor and treat T1DM.

Reactive oxygen species in cardiovascular diseases: an update

Cardiovascular diseases are among the leading causes of death worldwide, imposing major health threats. Reactive oxygen species (ROS) are one of the most important products from the process of redox reactions. In the onset and progression of cardiovascular diseases, ROS are believed to heavily influence homeostasis of lipids, proteins, DNA, mitochondria, and energy metabolism. As ROS production increases, the heart is damaged, leading to further production of ROS. The vicious cycle continues on as additional ROS are generated. For example, recent evidence indicated that connexin 43 (Cx43) deficiency and pyruvate kinase M2 (PKM2) activation led to a loss of protection in cardiomyocytes. In this context, a better understanding of the mechanisms behind ROS production is vital in determining effective treatment and management strategies for cardiovascular diseases.

TDAG51-Deficiency Podocytes are Protected from High-Glucose-Induced Damage Through Nrf2 Activation via the AKT-GSK-3β Pathway

T cell death-associated gene 51 (TDAG51) has been implicated in the development of various pathological conditions. However, whether TDAG51 plays a role in diabetic renal disease remains unknown. The current work investigated the possible function of TDAG51 in diabetic renal disease using high-glucose (HG)-stimulated podocytes in vitro. The elevation of TDAG51 was observed in podocytes in response to HG exposure and the glomeruli of diabetic mice. The siRNAs targeting TDAG51 were applied to deplete TDAG51 in HG-stimulated podocytes. Crucially, TDAG51 deficiency was sufficient to decrease the apoptosis, oxidative stress, and inflammation caused by HG. Mechanically, the inhibition of TDAG51 was capable of enhancing the activation of nuclear factor E2-related factor 2 (Nrf2) associated with the upregulation of AKT-glycogen synthase kinase-3β (GSK-3β) pathway. The reduction of AKT abolished the activation of Nrf2 elicited by TDAG51 deficiency. Additionally, the reduction of Nrf2 diminished the anti-HG injury effect elicited by TDAG51 deficiency. Overall, these data demonstrate that TDAG51 deficiency defends against HG-induced podocyte damage through Nrf2 activation by regulating AKT-GSK-3β pathway. This study suggests that TDAG1 may have a potential role in diabetic renal disease by affecting HG-induced podocyte damage.

Modulation of transcriptional mineralocorticoid receptor activity by casein kinase 1

The mineralocorticoid receptor (MR) with its ligand aldosterone (aldo) physiologically regulates electrolyte homeostasis and blood pressure but it can also lead to pathophysiological effects in the cardiovascular system. Previous results show that posttranslational modifications (PTM) can influence MR signaling and function. Based on in silico and in vitro data, casein kinase 1 (CK1) was predicted as a candidate for MR phosphorylation. To gain a deeper mechanistic insight into MR activation, we investigated the influence of CK1 on MR function in HEK cells. Co-immunoprecipitation experiments indicated that the MR is located in a protein-protein complex with CK1α and CK1ε. Reporter gene assays with pharmacological inhibitors and MR constructs demonstrated that especially CK1ε acts as a positive modulator of GRE activity via the C-terminal MR domains CDEF. CK1 enhanced the binding affinity of aldosterone to the MR, facilitated nuclear translocation and DNA interaction of the MR, and led to expression changes of pathophysiologically relevant genes like Per-1 and Phlda1. By peptide microarray and site-directed mutagenesis experiments, we identified the highly conserved T800 as a direct CK1 phosphorylation site of the MR, which modulates the nuclear import and genomic activity of the receptor. Direct phosphorylation of the MR was unable to fully account for all of the CK1 effects on MR signaling, suggesting additional phosphorylation of MR co-regulators. By LC/MS/MS, we identified the MR-associated proteins NOLC1 and TCOF1 as candidates for such CK1-regulated co-factors. Overall, we found that CK1 acts as a co-activator of MR GRE activity through direct and indirect phosphorylation, which accelerates cytosolic-nuclear trafficking, facilitates nuclear accumulation and DNA binding of the MR, and increases the expression of pathologically relevant MR-target genes.

VCAM1 expression in the myocardium is associated with the risk of heart failure and immune cell infiltration in myocardium

Ischemic heart disease (IHD) and dilated cardiomyopathy (DCM) are the two most common etiologies of heart failure (HF). Both forms share common characteristics including ventricle dilation in the final stage. Immune mechanisms in HF are increasingly highlighted and have been implicated in the pathogeneses of IHD and DCM. A better understanding of adhesion molecule expression and correlated immune cell infiltration could enhance disease detection and improve therapeutic targets. This study was performed to explore the common mechanisms underlying IHD and DCM. After searching the Gene Expression Omnibus database, we selected the GSE42955, GSE76701, GSE5406, GSE133054 and GSE57338 datasets for different expressed gene (DEGs) selection and new cohort establishment. We use xcell to calculate immune infiltration degree, ssGSEA and GSEA to calculate the pathway and biological enrichment score, consensus cluster to identify the m6A modification pattern, and LASSO regression to make risk predicting model and use new combined cohort to validate the results. The screening stage revealed that vascular cell adhesion molecule 1 (VCAM1) play pivotal roles in regulating DEGs. Subsequent analyses revealed that VCAM1 was differentially expressed in the myocardium and involved in regulating immune cell infiltration. We also found that dysregulated VCAM1 expression was associated with a higher risk of HF by constructing a clinical risk-predicting model. Besides, we also find a connection among the m6A RNA modification ,expression of VCAM1 and immune regulation. Those connection can be linked by the Wnt pathway enrichment alternation. Collectively, our results suggest that VCAM-1 have the potential to be used as a biomarker or therapy target for HF and the m6A modification pattern is associated with the VCAM1 expression and immune regulation.

Loss of PHLDA1 has a protective role in OGD/R-injured neurons via regulation of the GSK-3β/Nrf2 pathway

Pleckstrin homology-like domain, family A, member 1 (PHLDA1) is a multifunctional protein that plays a role in diverse pathological conditions. However, whether PHLDA1 participates in cerebral ischemia-reperfusion injury has not been reported. The goals of the present work were to assess the possible relationship between PHLDA1 and cerebral ischemia-reperfusion injury. Hippocampal neurons were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate cerebral ischemia-reperfusion injury in vitro, which led to significant increases in the expression of PHLDA1. Cellular functional studies showed that the knockdown of PHLDA1 produced a protective role in OGD/R-injured neurons via the down-regulation of neuronal apoptosis, oxidative stress and proinflammatory cytokine release. On the contrary, the overexpression of PHLDA1 rendered neurons more vulnerable to OGD/R injury. In-depth research revealed that the inhibition of PHLDA1 resulted in the enhancement of nuclear factor erythroid 2 like 2 (Nrf2) signaling in OGD/R-injured neurons. The reactivation of glycogen synthase kinase 3β (GSK-3β) abolished the PHLDA1-inhibition-mediated activation of Nrf2 signaling. Moreover, the restraint of Nrf2 signaling diminished the PHLDA1-knockdown-induced neuroprotective effects in OGD/R-injured neurons. In summary, the data of our work show that the loss of PHLDA1 protects against OGD/R injury via potentiating Nrf2 signaling via the regulation of GSK-3β. This work underscores a potential role of PHLDA1 in cerebral ischemia-reperfusion injury and proposes PHLDA1 as an attractive target for the development of neuroprotective therapy.

PHLDA3 inhibition attenuates endoplasmic reticulum stress-induced apoptosis in myocardial hypoxia/reoxygenation injury by activating the PI3K/AKT signaling pathway

Endoplasmic reticulum stress (ERS)-induced apoptosis serves a crucial role in the pathogenesis of myocardial ischemia/reperfusion injury (MIRI). Previous studies have confirmed that pleckstrin homology-like domain family A member 3 (PHLDA3) is an important mediator in ERS-associated apoptosis. The aim of the current study focused on whether PHLDA3 served protective effects on hypoxia/reoxygenation (H/R)-injured cardiomyocytes by inhibiting ERS-induced apoptosis. Furthermore, the molecular mechanisms associated with the PI3K/AKT signaling pathway were investigated. Primary neonatal rat cardiomyocytes were isolated and randomized into four groups: i) Control + adenovirus encoding scrambled short hairpin RNA (AdshRNA); ii) control + adenoviral vectors encoding PHLDA3 shRNA (AdshPHLDA3); iii) H/R+ AdshRNA and iv) H/R+AdshPHLDA3. AdshPHLDA3 was used to knock down PHLDA3. An H/R injury model was constructed by treatment with hypoxia for 4 h followed by reoxygenation for 6 h. A PI3K/AKT inhibitor, LY294002, was supplemented in mechanistic studies. Cell viability and LDH/CK releases were detected to evaluate myocardial damage. Flow cytometry assays were used to assess apoptotic response. Western blotting assays were used to detect protein expression. The results demonstrated that H/R induced myocardial damage and increased PHLDA3 expression. ERS-induced apoptosis was significantly increased following H/R injury, as indicated by increased apoptotic rates and ERS-associated protein expression, including those of CHOP, 78 kDa glucose-regulated protein and caspase-12. However, PHLDA3 inhibition following AdshPHLDA3 transfection reversed cell damage and ERS-associated apoptosis on H/R injury. Studies for molecular mechanisms concluded that the apoptosis-inhibition effects and cardioprotective roles of PHLDA3 inhibition were induced partly by the activation of the PI3K/AKT pathway, which was verified by LY294002 treatment. In conclusion, in the process of H/R injury, PHLDA3 inhibition reduced ERS-induced apoptosis and H/R injury by activating the PI3K/AKT pathway. PHLDA3 may be a therapeutic target for the treatment of MIRI.

miR-194 ameliorates hepatic ischemia/reperfusion injury via targeting PHLDA1 in a TRAF6-dependent manner

Hepatic ischemia/reperfusion injury (IRI) is an inevitable pathological process in liver resection, shock and transplantation. However, the internal mechanism of hepatic IRI, including inflammatory transduction of multiple signaling pathways, is not fully understood. In the present study, we identified pleckstrin homology-like domain family member 1 (PHLDA1), suppressed by microRNA (miR)-194, as a critical intersection of dual inflammatory signals in hepatic IRI. PHLDA1 was upregulated in hepatic IRI with a concomitant downregulation of miR-194. Overexpression of miR-194 diminished PHLDA1 and inhibitors of the nuclear factor kappa-B kinase (IKK) pathway, thus leading to remission of hepatic pathological injury, apoptosis and release of cytokines. Further enrichment of PHLDA1 reversed the function of miR-194 both in vivo and in vitro. For an in-depth query, we verified PHLDA1 as a direct target of miR-194. Notably, inflammatory signal transduction of PHLDA1 was induced by activating TNF receptor-associated factor 6 (TRAF6), sequentially initiating IKK and mitogen-activated protein kinase (MAPK), both of which aggravate stress and inflammation in hepatic IRI. In conclusion, the miR-194/PHLDA1 axis was a key upstream regulator of IKK and MAPK in hepatic IRI. Targeting PHLDA1 might be a potential strategy for hepatic IRI therapy.

Comparative transcriptomic analysis of vascular endothelial cells after hypoxia/re-oxygenation induction based on microarray technology

OBJECTIVE

To provide comprehensive data to understand mechanisms of vascular endothelial cell (VEC) response to hypoxia/re-oxygenation.

METHODS

Human umbilical vein endothelial cells (HUVECs) were employed to construct hypoxia/re-oxygenation-induced VEC transcriptome profiling. Cells incubated under 5% O₂, 5% CO₂, and 90% N₂ for 3 h followed by 95% air and 5% CO₂ for 1 h were used in the hypoxia/re-oxygenation group. Those incubated only under 95% air and 5% CO₂ were used in the normoxia control group.

RESULTS

By using a well-established microarray chip consisting of 58 339 probes, the study identified 372 differentially expressed genes. While part of the genes are known to be VEC hypoxia/re-oxygenation-related, serving as a good control, a large number of genes related to VEC hypoxia/re-oxygenation were identified for the first time. Through bioinformatic analysis of these genes, we identified that multiple pathways were involved in the reaction. Subsequently, we applied real-time polymerase chain reaction (PCR) and western blot techniques to validate the microarray data. It was found that the expression of apoptosis-related proteins, like pleckstrin homology-like domain family A member 1 (PHLDA1), was also consistently up-regulated in the hypoxia/re-oxygenation group. STRING analysis found that significantly differentially expressed genes SLC38A3, SLC5A5, Lnc-SLC36A4-1, and Lnc-PLEKHJ1-1 may have physical or/and functional protein-protein interactions with PHLDA1.

CONCLUSIONS

The data from this study have built a foundation to develop many hypotheses to further explore the hypoxia/re-oxygenation mechanisms, an area with great clinical significance for multiple diseases.

LHPP exerts a tumor-inhibiting role in glioblastoma via the downregulation of Akt and Wnt/β-catenin signaling

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) has been recently identified as a novel inhibitor of multiple tumors; however, its role in glioblastoma (GBM) has not been investigated. This study aimed to evaluate whether LHPP exerts a potential tumor-inhibiting role in GBM. Compared with that in normal tissues, LHPP expression was lower in GBM tissues and various GBM cell lines. LHPP up-regulation in GBM cells markedly reduced their proliferation and invasion, and its knockdown had an oncogenic effect on these cells. Further studies revealed that overexpressed LHPP decreased the levels of Akt and glycogen synthase-3β phosphorylation and down-regulated Wnt/β-catenin signaling. By contrast, LHPP knockdown produced opposite effects. Akt suppression markedly abrogated the activation of Wnt/β-catenin signaling induced by LHPP knockdown. The reactivation of Wnt/β-catenin signaling partially reversed the inhibition of tumor growth in GBM mediated by LHPP overexpression. In addition, LHPP overexpression markedly retarded the tumorigenesis of GBM cells in vivo. These findings revealed that LHPP acts a potential inhibitor of tumor growth in GBM, and its overexpression represses GBM proliferation and invasion by down-regulating Akt and Wnt/β-catenin signaling. This work highlights the crucial role of LHPP in GBM progression and suggests its potential as an anticancer target for the treatment of this disease.