Anti-apoptotic Pathways Research Articles

Integrated metabolomics and lipidomics reveals high accumulation of polyunsaturated lysoglycerophospholipids in human lung fibroblasts exposed to fine particulate matter

Exposure to fine particulate matter (PM) comprising toxic compounds arising from air pollution is a major human health concern. It is linked to increased mortality and incidence of various lung diseases. However, the mechanisms underlying the toxic effects of PM on lung fibroblasts have not been fully explored. We used targeted quantitative metabolomics and lipidomics analysis along with cytotoxicity studies to comprehensively characterize the alterations in the metabolite profiles of human lung fibroblasts (HEL 299) upon exposure to PM2.5 and PM10. This exposure at 50 μg/mL for 72 h induced an abnormally high apoptotic response via triggering intracellular reactive oxygen species (ROS) production and mitochondrial dysfunction through an imbalance between pro- and anti-apoptotic signaling pathways. The cytotoxic effects of PM2.5 were more severe than those of PM10. Metabolomics and lipidomics analyses revealed that PM exposure triggered substantial changes in the cellular metabolite profile, which involved reduced mitochondria-related metabolites such as tricarboxylic acid (TCA) cycle intermediates, amino acids, and free fatty acids as well as increased lysoglycerophospholipids (LPLs) containing polyunsaturated fatty acids. The decrease in mitochondria-related metabolites suggested that PM exposure led to reduced TCA cycle capacity and energy production. Apoptotic and inflammatory responses as well as mitochondrial dysfunction were likely to be accelerated because of excessive accumulation of LPLs, contributing to the disruption of membrane rafts and Ca2+ homeostasis and causing increased mitochondrial ROS formation. These results provide valuable insights regarding the toxic effects of PM exposure. Our study also provides a new direction for research on PM exposure-related health disorders using different cell lines.

Fibroblast–tumor cell signaling limits HER2 kinase therapy response via activation of MTOR and antiapoptotic pathways

Despite the implementation of multiple HER2-targeted therapies, patients with advanced HER2+ breast cancer ultimately develop drug resistance. Stromal fibroblasts represent an abundant cell type in the tumor microenvironment and have been linked to poor outcomes and drug resistance. Here, we show that fibroblasts counteract the cytotoxic effects of HER2 kinase-targeted therapy in a subset of HER2+ breast cancer cell lines and allow cancer cells to proliferate in the presence of the HER2 kinase inhibitor lapatinib. Fibroblasts from primary breast tumors, normal breast tissue, and lung tissue have similar protective effects on tumor cells via paracrine factors. This fibroblast-mediated reduction in drug sensitivity involves increased expression of antiapoptotic proteins and sustained activation of the PI3K/AKT/MTOR pathway, despite inhibition of the HER2 and the RAS-ERK pathways in tumor cells. HER2 therapy sensitivity is restored in the fibroblast cocultures by combination treatment with inhibitors of MTOR or the antiapoptotic proteins BCL-XL and MCL-1. Expression of activated AKT in tumor cells recapitulates the effects of fibroblasts resulting in sustained MTOR signaling and poor lapatinib response. Lapatinib sensitivity was not altered by fibroblasts in tumor cells that exhibited sustained MTOR signaling due to a strong gain-of-function PI3KCA mutation. These findings indicate that in addition to tumor cell-intrinsic mechanisms that cause constitutive PI3K/AKT/MTOR pathway activation, secreted factors from fibroblasts can maintain this pathway in the context of HER2 inhibition. Our integrated proteomic-phenotypic approach presents a strategy for the discovery of protective mechanisms in fibroblast-rich tumors and the design of rational combination therapies to restore drug sensitivity.

Genetic Variation in Response to Global Warming in a Coral Reef Species, Porites lobata

Climate change due to global warming is one of the worst environmental disasters in the world, which affects all ecosystems and has led to increasing degradation of coral reefs. The increase of sea surface temperature is inversely related to the resistance of corals and is directly associated with their bleaching. High temperature disrupts the symbiotic relationship between coral and algal symbiont and results in coral bleaching. To evaluate the adaptation of corals to heat stress, in this study, we investigated the thermal stress effect on the expression of genes involved in programmed cell death (PCD), cysteinyl aspartate proteases 3 (will be mentioned as Caspas3 hereafter) and anti-apoptotic pathway, B-cell lymphoma 2 (will be mentioned as Bcl2 hereafter) in Porites lobata (Dana, 1846). Corals were incubated at 25°C for 2 weeks (adaptation period) and then exposed to 34°C (heat shock) for 24 and 48 hours. Then, the expression of genes was measured using real-time PCR. The results revealed that both genes were up-regulated at 24 hours after heat induction. Bcl-2 expression (anti-apoptotic gene) was induced at 24 hours and was down-regulated at 48 hours. In contrast, Caspase3 (apoptotic gene) continued to be expressed up to 48 hours. These results might indicate that coral cells are headed towards bleaching and death with increased temperature. The results of this study, regarding the observed expression patterns, can clarify the response of different genes to a thermal stress in coral reefs. The exposure of corals to acute conditions with high temperatures presented the behavior of the desired genes in the studied conditions.

Combination therapy with anti-CD20 mAb and IL-10 gene to reverse type 1 diabetes by attenuating pancreatitis and inhibiting apoptosis in NOD mice

AimsTo assess the combination therapy of anti-CD20 mabs and adenovirus-mediated interleukin-10 (IL-10) gene delivery on the prevention of type 1 diabetes (T1D) in non-obese diabetes (NOD) mice. Main methodsIn present study, we simultaneously blocked the B cell interactions and recovered the Th cell subset proportion by using through anti-CD20 Mab and adenovirus-mediated gene delivery of IL-10, respectively. After 9 consecutive days of combination therapy, various measurements, including hematoxylin-eosin staining (HE), terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling assay (TUNEL), immunohistochemistry, ELISA, PCR and western blot were applied to further assess the efficacy. Key findingsThe results suggested that the combination intervention reduced the T1D-associated morbidity of NOD mice, promote insulin secretion, control blood glucose and ease pancreatitis. Moreover, the combination therapy might play a protective role in pancreatic β cells by suppressing the expression of TNF-α and Fas, blocking the Caspase-8 and Caspase-3 apoptotic pathways and activating the Bcl-2 anti-apoptotic pathway. Finally, the combination intervention may up-regulate the gene expression of CK-19 and PDX-1 and further accelerate the differentiation and proliferation of pancreatic β cells. SignificanceTherefore, the combination intervention with anti-CD20 mabs and the IL-10 gene plays a role in the prevention of T1D to some extent in NOD mice.

Oxypaeoniflorin improves myocardial ischemia/reperfusion injury by activating the Sirt1/Foxo1 signaling pathway.

Myocardial ischemia/reperfusion (MI/R) injury is a leading cause of damage to cardiac tissues and is associated with high mortality and disability rates worldwide. Oxypaeoniflorin (OPA) has been found to be the main constituent of Paeonia veitchii Lynch. This study was conducted to explore the effect of OPA on MI/R injury and its potential mechanism. An in vivo MI/R injury model was established by transient coronary ligation in BALB/c mice, and an in vitro hypoxia/reoxygenation (H/R) injury model was established with rat cardiomyocyte H9c2 cells. Echocardiographic assessments demonstrated that OPA significantly reduced disruption of cardiac function and improved the indicators of ejection fraction (EF) and fractional shortening (FS). The enzyme-linked immunosorbent assay (ELISA) results suggested that OPA significantly reduced the release of myocardial infarction-related factors, such as the creatine kinase (CK-MB), cardiac troponin I (cTnI) and cardiac troponin T (cTnT). Additionally, hematoxylin-eosin (HandE) staining demonstrated that OPA markedly inhibited the myocardial apoptosis and necrosis caused by MI/R. Consistently, the results obtained from the cell counting kit-8 (CCK-8) and flow cytometry assays revealed that OPA obviously reversed the H/R-induced decrease in cell activity and increase in apoptosis of H9c2 cells. Furthermore, western blot assays indicated that OPA inhibited apoptosis by activating the Sirt1 (silent information regulator factor 2 related enzyme 1)/Foxo1(forkhead transcription factor FKHR) signaling pathway in myocardial tissues and H9c2 cells. Collectively, these novel findings are the first to provide strong evidence that OPA attenuates MI/R injury by activating the Sirt1 (silent information regulator factor 2 related enzyme 1)/Foxo1(forkhead transcription factor FKHR) signaling-mediated anti-apoptotic pathway.

Role of Exosomal miRNAs and the Tumor Microenvironment in Drug Resistance.

Tumor microenvironment (TME) is composed of different cellular populations, such as stromal, immune, endothelial, and cancer stem cells. TME represents a key factor for tumor heterogeneity maintenance, tumor progression, and drug resistance. The transport of molecules via extracellular vesicles emerged as a key messenger in intercellular communication in the TME. Exosomes are small double-layered lipid extracellular vesicles that can carry a variety of molecules, including proteins, lipids, and nucleic acids. Exosomal miRNA released by cancer cells can mediate phenotypical changes in the cells of TME to promote tumor growth and therapy resistance, for example, fibroblast- and macrophages-induced differentiation. Cancer stem cells can transfer and enhance drug resistance in neighboring sensitive cancer cells by releasing exosomal miRNAs that target antiapoptotic and immune-suppressive pathways. Exosomes induce drug resistance by carrying ABC transporters, which export chemotherapeutic agents out of the recipient cells, thereby reducing the drug concentration to suboptimal levels. Exosome biogenesis inhibitors represent a promising adjunct therapeutic approach in cancer therapy to avoid the acquisition of a resistant phenotype. In conclusion, exosomal miRNAs play a crucial role in the TME to confer drug resistance and survivability to tumor cells, and we also highlight the need for further investigations in this promising field.

CFTR promotes malignant glioma development via up-regulation of Akt/Bcl2-mediated anti-apoptosis pathway.

Cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP‐activated Cl‐ channel, is extensively expressed in the epithelial cells of various tissues and organs. Accumulating evidence indicates that aberrant expression or mutation of CFTR is related to carcinoma development. Malignant gliomas are the most common and aggressive intracranial tumours; however, the role of CFTR in the development of malignant gliomas is unclear. Here, we report that CFTR is expressed in malignant glioma cell lines. Suppression of CFTR channel function or knockdown of CFTR suppresses glioma cell viability whereas overexpression of CFTR promotes it. Additionally, overexpression of CFTR suppresses apoptosis and promotes glioma progression in both subcutaneous and orthotopic xenograft models. Cystic fibrosis transmembrane conductance regulator activates Akt/Bcl2 pathway, and suppression of PI3K/Akt pathway abolishes CFTR overexpression–induced up‐regulation of Bcl2 (MK‐2206 and LY294002) and cell viability (MK‐2206). More importantly, the protein expression level of CFTR is significantly increased in glioblastoma patient samples. Altogether, our study has revealed a mechanism by which CFTR promotes glioma progression via up‐regulation of Akt/Bcl2‐mediated anti‐apoptotic pathway, which warrants future studies into the potential of using CFTR as a therapeutic target for glioma treatment.

Mesenchymal stem cells combined with liraglutide relieve acute lung injury through apoptotic signaling restrained by PKA/\u03b2-catenin

BackgroundARDS and ALI are life-threatening diseases with extremely high mortality in patients. Different sources of MSCs could mitigate the symptoms of ALI from diverse mechanisms. Liraglutide is an activator of glucagon-like peptide-1 receptor (GLP-1R) that activates anti-apoptotic pathways and exerts anti-inflammatory effects. We mainly compared the effects of human chorionic villus-derived mesenchymal stem cells (hCMSCs), human bone marrow-derived mesenchymal stem cells (hBMSCs), and human adipose-derived mesenchymal stem cells (hAMSCs) on the treatment of ALI and explored the apoptosis mechanism of combination MSCs of liraglutide.MethodsThe proliferation of MSCs was detected by MTT assay. Western blot and RT-qPCR were used to detect the expression of GLP-1R, SPC, Ang-1, and KGF in MSCs stimulated by LPS and liraglutide. By using flow cytometry and TUNEL assay to compare the apoptosis of three MSCs under the action of LPS and liraglutide, we selected hCMSCs as the target cells to study the expression of apoptotic protein through the PKA/β-catenin pathway. In ALI animal models, we observed the effects of liraglutide alone, MSCs alone, and MSCs combined with liraglutide by H&E staining, cell counting, immunohistochemistry, and ELISA assay.ResultsWe demonstrated that LPS attenuates the proliferation of the three MSCs and the expression of GLP-1R. Liraglutide could reverse the effects of LPS; increase the expression of SPC, Ang-1, and KGF; and can reduce the apoptosis of three MSCs through the PKA/β-catenin pathway. In the LPS-induced ALI model, MSCs combined with liraglutide showed a significant therapeutic effect, and hCMSCs combined with liraglutide have advantages in the treatment of ALI.ConclusionsThe therapeutic effect of combination MSCs of liraglutide on ALI was higher than that of MSCs alone or liraglutide alone, and liraglutide could alleviate the symptoms of ALI by reducing MSCs apoptosis.

Organ-Protective Effects and the Underlying Mechanism of Dexmedetomidine.

Dexmedetomidine (DEX) is a highly selective α2 adrenergic receptor (α2AR) agonist currently used in clinical settings. Because DEX has dose-dependent advantages of sedation, analgesia, antianxiety, inhibition of sympathetic nervous system activity, cardiovascular stabilization, and significant reduction of postoperative delirium and agitation, but does not produce respiratory depression and agitation, it is widely used in clinical anesthesia and ICU departments. In recent years, much clinical study and basic research has confirmed that DEX has a protective effect on a variety of organs, including the nervous system, heart, lungs, kidneys, liver, and small intestine. It acts by reducing the inflammatory response in these organs, activating antiapoptotic signaling pathways which protect cells from damage. Therefore, based on wide clinical application and safety, DEX may become a promising clinical multiorgan protection drug in the future. In this article, we review the physiological effects related to organ protection in α2AR agonists along with the organ-protective effects and mechanisms of DEX to understand their combined application value.

OR24-04 Ovarian Follicle Survival Is Determined by Follicle-Stimulating Hormone Receptor (FSHR) and Estrogen Receptor (GPER) Heteromers

Mechanisms regulating the selection of antral ovarian follicles are poorly understood and supposed to rely on low estrogen levels, decline of follicle-stimulating hormone (FSH) levels and receptor (FSHR) expression. These concepts are challenged in vitro, where apoptosis of human granulosa cells (hGLC) and transfected cell lines is induced by high doses of FSH or FSHR overexpression, while estrogens induce anti-apoptotic signals via nuclears and a G protein-coupled estrogen receptor (GPER). Therefore, in vitro data suggest that antral follicle selection may be driven by underestimated, FSH/FSHR-dependent apoptotic signals due to transiently maximized FSHR expression and overload of cAMP signalling, prevailing on estrogen-dependent signals. Here we demonstrate how FSHR/GPER physical interaction rescue ovarian follicles from FSH-mediated death. 10 nM FSH induces high intracellular levels of cAMP, measured by bioluminescence resonance energy transfer (BRET), and apoptosis in cultured hGLC under conditions where GPER levels are depleted by siRNA. This result was confirmed in transfected HEK293 cells overexpressing FSHR. Using BRET, photo-activated localization microscopy (PALM) and bioinformatics prodiction, we also demonstrate FSHR/GPER heteromers at the cell surface. The role of FSHR/GPER heteromers may be relevant to inhibit FSH-induced death signals, since increasing GPER expression levels in HEK293 cells co-expressing FSHR results in displacement of the Gαs-protein to FSHR, blockade of FSH-induced cAMP production and inhibition of apoptosis. However, in HEK293 cells coexpressing GPER/FSHR, FSH-induced activation of the anti-apoptotic AKT-pathway via a Gβγ-dependent mechanism, as demonstrated by Western blotting in cells treated using the inhibitor gallein. Inhibition of both FSH-induced cAMP production and apoptosis was lost when FSHR is coexpressed together with a mutant GPER, unable to heteromerize with FSHR, as well as in KO HEK293 cells unable to produce a molecular complex associated with GPER inhibiting cAMP. GPER/FSHR coexpression is confirmed in secondary follicles from paraffin-embedded tissues of human ovary by immunohistochemistry, suggesting that FSHR-GPER heterodimers could be physiologically relevant in vivo for inhibiting cAMP-linked apoptosis. Most importantly, FSHR and GPER co-expression correlates in hGLC from FSH-normo-responder women undergoing assisted reproduction, while it is not in hGLC from FSH-poor-responders, where increasing FSHR mRNA levels do not correspond to increasing GPER mRNA levels. We demonstrate that death signals in atretic follicles are delivered through overexpressed FSHR and inhibited by FSHR/GPER heteromerization, activating anti-apoptotic pathways. This finding unveils a novel working model of the physiology of dominant follicle selection and the relationship between FSH and estrogens.

Structure-activity relationship and pathway of antioxidant shrimp peptides in a PC12 cell model

Abstract This study aimed to investigate that the antioxidant capacity of the peptides Met-Thr-Thr-Asp-Ile (MTTNI) and Met-Thr-Thr-Asp-Leu (MTTNL) purified from shrimp protein hydrolysate (SPH), identified by UPLC-Q-TOF-MS, and the related signaling pathways that inhibit oxidative stress. The results indicated that the inhibition ratios of MTTNI and MTTNL hydroxyl radical scavenging activities were 10.71 ± 3.27% and 8.94 ± 0.97%, respectively, and those of their DPPH radical scavenging activities were 43.21 ± 3.55% and 38.74 ± 2.82%, respectively. The two peptides significantly decreased ROS content in PC12 cells and upregulated SOD activity to the level of the scopolamine group. Moreover, MTTNL and MTTNI could modulate oxidative stress in vitro, and the presence of Leu in the peptide sequence may be the critical factor contributing to stronger antioxidant activity than peptide sequences with Ile. MTTNL western blot analysis showed Leu suppresses Bax, Caspase-3, and p53 expression, as well as BCL-XL overexpression, thus protecting PC12 cells from oxidative stress. Overall, the peptides protected neurons from oxidative damage through the anti-apoptotic pathway.

Application of mesoporous silica nanoparticles for drug delivery to cancer cells

Cancer is one of the main causes of death worldwide. Chemotherapy is the most common method for cancer therapy which represent non-specific side effects on normal cells and tissues and drug resistance in cancer cells. There are two main mechanisms for Multi Drug Resistance (MDR) in cancer cells including: drug efflux pump and activation of anti-apoptotic pathways. Cancer chemotherapy disadvantages can be overcome by using nanoparticulate drug delivery systems like Mesoporous Silica Nanoparticles (MSNs) that have been used as drug delivery system since 2001. The present review included synthesis, targeted (active or passive) drug delivery to cancer cells, co-delivery of anticancer drugs and siRNA by MSNs and its toxicity. This review revealed that MSNs are good candidate for drug delivery to cancer cells due to its unique properties including: controllable pore and particle sizes, thermal and chemical stability, modifications of outer and inner surfaces of nanoparticles for drug and siRNA loading, attachment of ligand for targeted drug delivery, high drug loading capacity and controlled drug release, biocompatibility and biodegradation in aqueous medium.

Neuroprotective Effect of Nilotinib on Cortical Pyramidal Cells, Histological, Morphometric and Biochemical Study

Introduction: Death of neuronal cell and gliosis are the two main pathological hallmarks induced by nervous tissue stress like conditions such as status epilepticus. Previous studies have mentioned that neuronal cell death occur as a result of different mechanisms, namely, necrosis and apoptosis. Although more recent studies have explained the cell death on the basis of autophagy. Many antiepileptic drugs are marketed, taking into consideration the antioxidant role of nilotinib and support its use as a favorable antiepileptic drug. The aim of the present study is to assess the neuroprotective effect of antiepileptic drug nilotinib on cortical tissue in rats.
 Materials and Methods: Sixty adult male rats were divided into three groups: (1) Control group, (2) pentylenetetrazol group (injected with pentylenetetrazol 60 mg/kg, subcutaneously), (3) nilotinib and pentylenetetrazol group (pretreated with nilotinib, 25 mg/kg daily for seven days prior to pentylenetetrazol administration). Latency of seizure and level of either oxidant or antioxidant enzymes in the cortical tissue was assessed. The histopathological changes in the cerebral cortex were studied also using hematoxylin and eosin stain.
 Results: Nilotinib increased the latency period of convulsions, increased the antioxidant enzymes levels with regain of the normal histological features.
 Conclusions: Nilotinib proved to promote the antioxidant, antiapoptotic pathways, anti-inflammatory and inhibiting autophagy which favor its use as an anti-epileptic drug.

The protection effects of survivin in the cell model of CVB3-induced viral myocarditis.

Viral myocarditis (VMC) is a widely studied but poorly understood inflammatory cardiomyopathy which mainly affects children and young adults and results in adverse outcomes. Cardiomyocyte apoptosis was reported important in the progress of coxsackievirus B3 (CVB3)-induced VMC and the blocking of this process may contribute to the therapeutic effect towards VMC. Therefore, this study was designed to explore whether survivin, one of the strongest antiapoptotic proteins, can protect cardiomyocytes from apoptosis in VMC and to discover its related mechanisms. Here, the cultured neonatal mouse cardiomyocytes (NMCs) were exposed to CVB3 to establish the cell model of VMC and the results of Western Blot showed that the protein expression of survivin in CVB3-infected NMCs varied at different post-infection time. Lentivirus was next used to examine the function of survivin in CVB3-infected NMCs. TUNEL assay demonstrated that the overexpression of survivin interrupted CVB3-induced apoptosis. It was next examined whether caspase-3 and -9 were involved in the antiapoptotic pathway initiated by survivin via Western Blot. The results showed a reverse relationship between the protein expression of survivin and that of cleaved caspase-3 and cleaved caspase-9, suggesting that survivin may attenuate apoptosis through restraining the activity of caspase-3 and -9. Moreover, the supernatant fluid of cultured NMCs was extracted to detect the quantitation of released lactate dehydrogenase (LDH) and a sharp decrease was discovered in the survivin-overexpressed group compared to the CVB3-infected group, indicating a protective role of survivin in the cell model of CVB3-induced myocarditis. This study demonstrated that survivin was triggered by CVB3 infection in NMCs and survivin executed its antiapoptotic effects via caspase-3- and caspase-9-dependent signaling pathway.

MicroRNA profiling in the Weddell seal suggests novel regulatory mechanisms contributing to diving adaptation

BackgroundThe Weddell Seal (Leptonychotes weddelli) represents a remarkable example of adaptation to diving among marine mammals. This species is capable of diving > 900 m deep and remaining underwater for more than 60 min. A number of key physiological specializations have been identified, including the low levels of aerobic, lipid-based metabolism under hypoxia, significant increase in oxygen storage in blood and muscle; high blood volume and extreme cardiovascular control. These adaptations have been linked to increased abundance of key proteins, suggesting an important, yet still understudied role for gene reprogramming.In this study, we investigate the possibility that post-transcriptional gene regulation by microRNAs (miRNAs) has contributed to the adaptive evolution of diving capacities in the Weddell Seal.ResultsUsing small RNA data across 4 tissues (brain, heart, muscle and plasma), in 3 biological replicates, we generate the first miRNA annotation in this species, consisting of 559 high confidence, manually curated miRNA loci. Evolutionary analyses of miRNA gain and loss highlight a high number of Weddell seal specific miRNAs.Four hundred sixteen miRNAs were differentially expressed (DE) among tissues, whereas 80 miRNAs were differentially expressed (DE) across all tissues between pups and adults and age differences for specific tissues were detected in 188 miRNAs. mRNA targets of these altered miRNAs identify possible protective mechanisms in individual tissues, particularly relevant to hypoxia tolerance, anti-apoptotic pathways, and nitric oxide signal transduction. Novel, lineage-specific miRNAs associated with developmental changes target genes with roles in angiogenesis and vasoregulatory signaling.ConclusionsAltogether, we provide an overview of miRNA composition and evolution in the Weddell seal, and the first insights into their possible role in the specialization to diving.

TBHQ Attenuates Neurotoxicity Induced by Methamphetamine in the VTA through the Nrf2/HO-1 and PI3K/AKT Signaling Pathways.

Methamphetamine (METH) leads to nervous system toxicity. Long-term exposure to METH results in damage to dopamine neurons in the ventral tegmental area (VTA), and depression-like behavior is a clinical symptom of this toxicity. The current study was designed to investigate whether the antioxidant tertiary butylhydroquinone (TBHQ) can alleviate neurotoxicity through both antioxidative stress and antiapoptotic signaling pathways in the VTA. Rats were randomly divided into a control group, a METH-treated group (METH group), and a METH+TBHQ-treated group (METH+TBHQ group). Intraperitoneal injections of METH at a dose of 10 mg/kg were administered to the rats in the METH and METH+TBHQ groups for one week, and METH was then administered at a dose that increased by 1 mg/kg per week until the sixth week, when the daily dosage reached 15 mg/kg. The rats in the METH+TBHQ group received 12.5 mg/kg TBHQ intragastrically. Chronic exposure to METH resulted in increased immobility times in the forced swimming test (FST) and tail suspension test (TST) and led to depression-like behavior. The production of reactive oxygen species (ROS) and apoptosis levels were increased in the VTA of animals in the METH-treated group. METH downregulated Nrf2, HO-1, PI3K, and AKT, key factors of oxidative stress, and the apoptosis signaling pathway. Moreover, METH increased the caspase-3 immunocontent. These changes were reversed by treatment with the antioxidant TBHQ. The results indicate that TBHQ can enhance Nrf2-induced antioxidative stress and PI3K-induced antiapoptotic effects, which can alleviate METH-induced ROS and apoptosis, and that the crosstalk between Nrf2 and PI3K/AKT is likely the key factor involved in the protective effect of TBHQ against METH-induced chronic nervous system toxicity.

Deacetylase-independent function of SIRT6 couples GATA4 transcription factor and epigenetic activation against cardiomyocyte apoptosis.

SIRT6 deacetylase activity improves stress resistance via gene silencing and genome maintenance. Here, we reveal a deacetylase-independent function of SIRT6, which promotes anti-apoptotic gene expression via the transcription factor GATA4. SIRT6 recruits TIP60 acetyltransferase to acetylate GATA4 at K328/330, thus enhancing its chromatin binding capacity. In turn, GATA4 inhibits the deacetylase activity of SIRT6, thus ensuring the local chromatin accessibility via TIP60-promoted H3K9 acetylation. Significantly, the treatment of doxorubicin (DOX), an anti-cancer chemotherapeutic, impairs the SIRT6–TIP60–GATA4 trimeric complex, blocking GATA4 acetylation and causing cardiomyocyte apoptosis. While GATA4 hyperacetylation-mimic retains the protective effect against DOX, the hypoacetylation-mimic loses such ability. Thus, the data reveal a novel SIRT6–TIP60–GATA4 axis, which promotes the anti-apoptotic pathway to prevent DOX toxicity. Targeting the trimeric complex constitutes a new strategy to improve the safety of DOX chemotherapy in clinical application.

The loss of endogenous Neuregulin‐4 impairs intestinal epithelial recovery from LPS‐induced injury.

Growth factor receptors such as EGFR/erbB family members can preserve intestinal integrity by the activation of anti‐apoptotic pathways and stabilization of epithelial tight junction components. Previously we have shown that the activation of ErbB4 by its specific ligand Neuregulin‐4 (NRG4) promotes epithelial cell survival through Src and PI3 kinase/AKT pathways and reduces intestinal inflammation. However, it is unclear whether ErbB4 is an essential regulator of the intestinal barrier and if endogenous NRG4 is required for the response to intestinal inflammation. In this study we investigated the role of endogenous NRG4 as it pertains to intestinal barrier function and cell survival in vivo.METHODSNRG4 knockout mice and wild type littermates were challenged with lipopolysaccharide (LPS) injection. Intestinal permeability was determined by gavaging with 4‐kDa FITC‐dextran and collecting blood for fluorescence analysis after 4 or 24 h. The relative mRNA level of inflammatory cytokines was determined by taqman gene assays using full thickness ileal homogenates. Fixed ileal tissue for analysis of apoptosis was assessed by TUNEL and cleaved caspase‐3 staining, proliferation was evaluated by KI67 staining, and tight junction localization was determined by ZO‐1 staining.RESULTSThe loss of endogenous NRG4 in unchallenged mice did not alter baseline intestinal permeability, apoptosis, or proliferation. Interestingly, baseline inflammatory cytokine levels were reduced in the NRG4‐null mice compared to WT littermates. NRG4 KO mice showed significantly increased permeability to 4‐kDa FITC‐dextran (P<0.05) and enterocyte apoptosis (P<0.05) 24 hours after LPS‐induced injury, which was not seen 4 hours after LPS challenge. Furthermore, ZO‐1 redistribution was apparent within the base of the crypt 24 hours after LPS challenge in the NRG4 KO mice, while redistribution was only visible after 4 hours in WT mice.CONCLUSIONThe loss of endogenous NRG4 impairs the recovery of intestinal epithelial barrier after LPS‐induced injury. Further investigation of this recovery mechanism may reveal more effective strategies for targeting epithelial barrier dysfunction seen in intestinal diseases such as inflammatory bowel disease.Support or Funding Information2 R01 DK095004 06A1

Regulation of Protein Synthesis and Apoptosis in Lymphocytes of Parkinson Patients: The Effect of Dopaminergic Treatment

Background: Parkinson disease (PD) is a neurodegenerative disorder characterized by progressive degeneration of the dopaminergic neurons in the substantia nigra, presumably due to increased apoptosis. In previous studies, we showed altered expression of proteins involved in mammalian target of rapamycin (mTOR) antiapoptotic and double-stranded RNA-dependent protein kinase (PKR) apoptotic pathways of translational control in experimental cellular and animal models of PD. Results: In this work, our results showed clear modifications in the expression of kinases involved in mTOR and PKR apoptosis pathways, in lymphocytes of PD patients treated or not with anti-PD treatment (levodopa), which confirmed the role played by apoptosis in the pathogenesis of this disease and the positive effect of treatment with medication on this parameter. Others proteins involved in apo­ptosis were also evaluated in lymphocytes of patients as the expression of the peripheral benzodiazepine receptor and caspase-3. Conclusion: Translational control is altered in PD and hence its evaluation in peripheral blood mononuclear cells may serve as an early marker of apoptosis and indicate the efficacy of the dopaminergic treatment.

CIRBP Ameliorates Neuronal Amyloid Toxicity via Antioxidative and Antiapoptotic Pathways in Primary Cortical Neurons.

It is generally accepted that the amyloid β (Aβ) peptide toxicity contributes to neuronal loss and is involved in the initiation and progression of Alzheimer's disease (AD). Cold-inducible RNA-binding protein (CIRBP) is reported to be a general stress-response protein, which is induced by different stress conditions. Previous reports have shown the neuroprotective effects of CIRBP through the suppression of apoptosis via the Akt and ERK pathways. The objective of this study is to examine the effect of CIRBP against Aβ-induced toxicity in cultured rat primary cortical neurons and attempt to uncover its underlying mechanism. Here, MTT, LDH release, and TUNEL assays showed that CIRBP overexpression protected against both intracellular amyloid β- (iAβ-) induced and Aβ25-35-induced cytotoxicity in rat primary cortical neurons. Electrophysiological changes responsible for iAβ-induced neuronal toxicity, including an increase in neuronal resting membrane potentials and a decrease in K+ currents, were reversed by CIRBP overexpression. Western blot results further showed that Aβ25-35 treatment significantly increased the level of proapoptotic protein Bax, cleaved caspase-3, and cleaved caspase-9 and decreased the level of antiapoptotic factor Bcl-2, but were rescued by CIRBP overexpression. Furthermore, CIRBP overexpression prevented the elevation of ROS induced by Aβ25-35 treatment by decreasing the activities of oxidative biomarker and increasing the activities of key enzymes in antioxidant system. Taken together, our findings suggested that CIRBP exerted protective effects against neuronal amyloid toxicity via antioxidative and antiapoptotic pathways, which may provide a promising candidate for amyloid-based AD prevention or therapy.