PKB and the mitochondria: AKTing on apoptosis

Integrated UPLC-ESI-MS/MS, network pharmacology, and transcriptomics to reveal the material basis and mechanism of Schisandra chinensis Fruit Mixture against diabetic nephropathy

Backgrounds

It has been regarded as an essential treatment option for diabetic nephropathy (DN) in Traditional Chinese medicine. Previous studies have demonstrated the anti-DN efficacy of Schisandra chinensis Fruit Mixture (SM); however, a comprehensive chemical fingerprint is still uncertain, and its mechanism of action, especially the potential therapeutic targets of anti-DN, needs to be further elucidated.

Objective

Potential mechanisms of SM action on DN were explored through network pharmacology and experimental validation.

Methods

The chemical composition of SM was analyzed using UPLC-ESI-MS/MS technology. Active bioactive components and potential targets of SM were identified using TCMSP, SwissDrugDesign, and SymMap platforms. Differentially expressed genes were determined using microarray gene data from the GSE30528 dataset. Related genes for DN were obtained from online databases, which include GeneCards, OMIM and DisGeNET. PPI networks and compound-target-pathway networks were constructed using Cytoscape. Functional annotation was performed using R software for GO enrichment and KEGG pathway analysis. The DN model was built for experimental validation using a high-sugar and high-fat diet combined with STZ induction. Hub targets and critical signaling pathways were detected using qPCR, Western blotting and immunofluorescence.

Results

Utilizing the UPLC-ESI-MS/MS coupling technique, a comprehensive analysis identified 1281 chemical components of SM's ethanol extract, with 349 of these components recognized as potential bioactive compounds through network pharmacology. Through this analysis, 126 shared targets and 15 HUB targets were pinpointed. Of these, JAK2 is regarded as the most critical gene. Enrichment analysis revealed that SM primarily operates within the PI3K/AKT signaling pathway. In vivo experiments confirmed that SM improved pathological injury and renal function in rats with DN while improving mitochondrial morphology and function and modulating the expression of proteins linked to apoptosis (cleaved-caspase-3, Bax, and Bcl-2) and pro-inflammatory factors (IL-6 and TNF-α). Mechanistically, SM alleviates DN primarily by suppressing the PI3K/AKT/mTOR and JAK2/STAT3 signaling pathways to fulfill the energy needs of renal tissues. Furthermore, molecular docking analysis provided direct validation of these findings.

Conclusion

The findings of this study offer initial indications of the active component and robust anti-inflammatory and anti-apoptotic characteristics of SM in the mitigation of DN, along with its capacity to safeguard the integrity and functionality of mitochondria. This research unequivocally validates the favorable anti-DN effects of SM, indicating its potential as a viable pharmaceutical agent for the management of DN.

The Role of Mitochondria in Statin-Induced Myopathy

Statins represent the primary therapy for combatting hypercholesterolemia and reducing mortality from cardiovascular events. Despite their pleiotropic effects in lowering cholesterol synthesis, circulating cholesterol, as well as reducing the risk of other systemic diseases, statins have adverse events in a small, but significant, population of treated patients. The most prominent of these adverse effects is statin-induced myopathy, which lacks precise definition but is characterised by elevations in the muscle enzyme creatine kinase alongside musculoskeletal complaints, including pain, weakness and fatigue. The exact aetiology of statin-induced myopathy remains to be elucidated, although impaired mitochondrial function is thought to be an important underlying cause. This may result from or be the consequence of several factors including statin-induced inhibition of coenzyme Q10 (CoQ10) biosynthesis, impaired Ca2+ signalling and modified reactive oxygen species (ROS) generation. The purpose of this review article is to provide an update on the information available linking statin therapy with mitochondrial dysfunction and to outline any mechanistic insights, which may be beneficial in the future treatment of myopathic adverse events.

Pleiotropy with sex-specific traits reveals genetic aspects of sex differences in Parkinson's disease

Parkinson's disease is an age-related neurodegenerative disorder with a higher incidence in males than females. The causes for this sex difference are unknown. Genome-wide association studies (GWAS) have identified 90 Parkinson's disease risk loci, but the genetic studies have not found sex-specific differences in allele frequency on autosomal chromosomes or sex chromosomes. Genetic variants, however, could exert sex-specific effects on gene function and regulation of gene expression. To identify genetic loci that might have sex-specific effects, we studied pleiotropy between Parkinson's disease and sex-specific traits. Summary statistics from GWASs were acquired from large-scale consortia for Parkinson's disease (n cases = 13 708; n controls = 95 282), age at menarche (n = 368 888 females) and age at menopause (n = 69 360 females). We applied the conditional/conjunctional false discovery rate (FDR) method to identify shared loci between Parkinson's disease and these sex-specific traits. Next, we investigated sex-specific gene expression differences in the superior frontal cortex of both neuropathologically healthy individuals and Parkinson's disease patients (n cases = 61; n controls = 23). To provide biological insights to the genetic pleiotropy, we performed sex-specific expression quantitative trait locus (eQTL) analysis and sex-specific age-related differential expression analysis for genes mapped to Parkinson's disease risk loci. Through conditional/conjunctional FDR analysis we found 11 loci shared between Parkinson's disease and the sex-specific traits age at menarche and age at menopause. Gene-set and pathway analysis of the genes mapped to these loci highlighted the importance of the immune response in determining an increased disease incidence in the male population. Moreover, we highlighted a total of nine genes whose expression or age-related expression in the human brain is influenced by genetic variants in a sex-specific manner. With these analyses we demonstrated that the lack of clear sex-specific differences in allele frequencies for Parkinson's disease loci does not exclude a genetic contribution to differences in disease incidence. Moreover, further studies are needed to elucidate the role that the candidate genes identified here could have in determining a higher incidence of Parkinson's disease in the male population.

Iridium(III) complex induces apoptosis in HeLa cells by regulating mitochondrial and PI3K/AKT signaling pathways: In vitro and in vivo experiments

Cyclometalated iridium complexes with mitochondrial targeting show great potential as substitutes for platinum-based complexes because of their strong anti-cancer properties. Three novel cyclometalated iridium(III) compounds were synthesized and evaluated in five different cell lines as part of the ongoing systematic investigations of these compounds. The complexes were prepared using 4,7-dichloro-1,10-phenanthroline ligands. The cytotoxicity of complexes Ir1-Ir3 towards HeLa cells was shown to be high, with IC50 values of 0.83±0.06, 4.73±0.11, and 4.95±0.62 μM, respectively. Complex Ir1 could be ingested by HeLa cells in 3 h and has shown high selectivity toward mitochondria. Subsequent investigations demonstrated that Ir1 triggered apoptosis in HeLa cells by augmenting the generation of reactive oxygen species (ROS), reducing the mitochondrial membrane potential, and depleting ATP levels. Furthermore, the movement of cells was significantly suppressed and the progression of the cell cycle was arrested in the G0/G1 phase following the administration of Ir1. The Western blot analysis demonstrated that the induction of apoptosis in HeLa cells by Ir1 involves the activation of the mitochondria-dependent channel and the PI3K/AKT signaling pathway. No significant cytotoxicity was observed in zebrafish embryos at concentrations less than or equal to 16 µM, e.g., survival rate and developmental abnormalities. In vivo, antitumor assay demonstrated that Ir1 suppressed tumor growth in mice. Therefore, our work shows that complex Ir1 could be a promising candidate for developing novel antitumor drugs.

Anaphylatoxin C5a receptor signaling induces mitochondrial fusion and sensitizes retinal pigment epithelial cells to oxidative stress

Mitochondrial dynamics is a morphological balance between fragmented and elongated shapes, reflecting mitochondrial metabolic status, cellular damage, and mitochondrial dysfunction. The anaphylatoxin C5a derived from complement component 5 cleavage, enhances cellular responses involved in pathological stimulation, innate immune responses, and host defense. However, the specific response of C5a and its receptor, C5a receptor (C5aR), in mitochondria is unclear. Here, we tested whether the C5a/C5aR signaling axis affects mitochondrial morphology in human-derived retinal pigment epithelial cell monolayers (ARPE-19). C5aR activation with the C5a polypeptide induced mitochondrial elongation. In contrast, oxidatively stressed cells (H2O2) responded to C5a with an enhancement of mitochondrial fragmentation and an increase in the number of pyknotic nuclei. C5a/C5aR signaling increased the expression of mitochondrial fusion-related protein, mitofusin-1 (MFN1) and - 2 (MFN2), as well as enhanced optic atrophy-1 (Opa1) cleavage, which are required for mitochondrial fusion events, whereas the mitochondrial fission protein, dynamin-related protein-1 (Drp1), and mitogen-activated protein kinase (MAPK)-dependent extracellular signal-regulated protein kinase (Erk1/2) phosphorylation were not affected. Moreover, C5aR activation increased the frequency of endoplasmic reticulum (ER)-mitochondria contacts. Finally, oxidative stress induced in a single cell within an RPE monolayer (488 nm blue laser spot stimulation) induced a bystander effect of mitochondrial fragmentation in adjacent surrounding cells only in C5a-treated monolayers. These results suggest that C5a/C5aR signaling produced an intermediate state, characterized by increased mitochondrial fusion and ER-mitochondrial contacts, that sensitizes cells to oxidative stress, leading to mitochondrial fragmentation and cell death.

Neuroprotective effects of novel compound FMDB on cognition, neurogenesis and apoptosis in APP/PS1 transgenic mouse model of Alzheimer's disease

Clinical and experimental studies have shown that the sharp reduction of estrogen is one of the important reasons for the high incidence of Alzheimer's disease (AD) in elderly women, but there is currently no such drug for treatment of AD. Our group first designed and synthesized a novel compound R-9-(4fluorophenyl)-3-methyl-10,10,-Hydrogen-6-hydrogen-benzopyran named FMDB. In this study, our aim is to investigate the neuroprotective effects and mechanism of FMDB in APP/PS1 transgenic mice. 6 months old APP/PS1 transgenic mice were intragastrical administered with FMDB (1.25, 2.5 and 5 mg/kg) every other day for 8 weeks. LV-ERβ-shRNA was injected bilaterally into the hippocampus of APP/PS1 mice to knockdown estrogen receptor β (ERβ). We found that FMDB ameliorated cognitive impairment in the Morris water maze and novel object recognition tests, increased hippocampal neurogenesis and prevented hippocampal apoptotic responses in APP/PS1 mice. Importantly, FMDB activated nuclear ERβ mediated CBP/p300, CREB and brain-derived neurotrophic factor (BDNF) signaling, and membrane ERβ mediated PI3K/Akt, CREB and BDNF signaling in the hippocampus. Our study demonstrated the contributions and mechanism of FMDB to cognition, neurogenesis and apoptosis in APP/PS1 mice. These lay the experimental foundation for the development of new anti-AD drugs.

Towards Kinase Inhibitor Therapies for Fragile X Syndrome: Tweaking Twists in the Autism Spectrum Kinase Signaling Network

Absence of the Fragile X Mental Retardation Protein (FMRP) causes autism spectrum disorders and intellectual disability, commonly referred to as the Fragile X syndrome. FMRP is a negative regulator of protein translation and is essential for neuronal development and synapse formation. FMRP is a target for several post-translational modifications (PTMs) such as phosphorylation and methylation, which tightly regulate its cellular functions. Studies have indicated the involvement of FMRP in a multitude of cellular pathways, and an absence of FMRP was shown to affect several neurotransmitter receptors, for example, the GABA receptor and intracellular signaling molecules such as Akt, ERK, mTOR, and GSK3. Interestingly, many of these molecules function as protein kinases or phosphatases and thus are potentially amendable by pharmacological treatment. Several treatments acting on these kinase-phosphatase systems have been shown to be successful in preclinical models; however, they have failed to convincingly show any improvements in clinical trials. In this review, we highlight the different protein kinase and phosphatase studies that have been performed in the Fragile X syndrome. In our opinion, some of the paradoxical study conclusions are potentially due to the lack of insight into integrative kinase signaling networks in the disease. Quantitative proteome analyses have been performed in several models for the FXS to determine global molecular processes in FXS. However, only one phosphoproteomics study has been carried out in Fmr1 knock-out mouse embryonic fibroblasts, and it showed dysfunctional protein kinase and phosphatase signaling hubs in the brain. This suggests that the further use of phosphoproteomics approaches in Fragile X syndrome holds promise for identifying novel targets for kinase inhibitor therapies.

Research Progress on Targeted Antioxidant Therapy and Vitiligo

Vitiligo is a common acquired depigmenting disease characterized by the loss of functional melanocytes and epidermal melanin. Vitiligo has a long treatment cycle and slow results, which is one of the most difficult challenges for skin diseases. Oxidative stress plays an important role as an initiating and driving factor in the pathogenesis of vitiligo. Antioxidant therapy has recently become a research hotspot in vitiligo treatment. A series of antioxidants has been discovered and applied to the treatment of vitiligo, which has returned satisfactory results. This article briefly reviews the relationship between oxidative stress and vitiligo. We also describe the progress of targeted antioxidant therapy in vitiligo, with the aim of providing a reference for new drug development and treatment options for this condition.

Mammalian AKT, the Emerging Roles on Mitochondrial Function in Diseases

Mitochondrial dysfunction may play a crucial role in various diseases due to its roles in the regulation of energy production and cellular metabolism. Serine/threonine kinase (AKT) is a highly recognized antioxidant, immunomodulatory, anti-proliferation, and endocrine modulatory molecule. Interestingly, increasing studies have revealed that AKT can modulate mitochondria-mediated apoptosis, redox states, dynamic balance, autophagy, and metabolism. AKT thus plays multifaceted roles in mitochondrial function and is involved in the modulation of mitochondria-related diseases. This paper reviews the protective effects of AKT and its potential mechanisms of action in relation to mitochondrial function in various diseases.

Keratins as an Inflammation Trigger Point in Epidermolysis Bullosa Simplex

Epidermolysis bullosa simplex (EBS) is a group of inherited keratinopathies that, in most cases, arise due to mutations in keratins and lead to intraepidermal ruptures. The cellular pathology of most EBS subtypes is associated with the fragility of the intermediate filament network, cytolysis of the basal layer of the epidermis, or attenuation of hemidesmosomal/desmosomal components. Mutations in keratins 5/14 or in other genes that encode associated proteins induce structural disarrangements of different strengths depending on their locations in the genes. Keratin aggregates display impaired dynamics of assembly and diminished solubility and appear to be the trigger for endoplasmic reticulum (ER) stress upon being phosphorylated by MAPKs. Global changes in cellular signaling mainly occur in cases of severe dominant EBS mutations. The spectrum of changes initiated by phosphorylation includes the inhibition of proteasome degradation, TNF-α signaling activation, deregulated proliferation, abnormal cell migration, and impaired adherence of keratinocytes. ER stress also leads to the release of proinflammatory danger-associated molecular pattern (DAMP) molecules, which enhance avalanche-like inflammation. Many instances of positive feedback in the course of cellular stress and the development of sterile inflammation led to systemic chronic inflammation in EBS. This highlights the role of keratin in the maintenance of epidermal and immune homeostasis.

Neuroprotective effects of novel compound Tozan on cognition, neurogenesis and apoptosis in diabetes

Background

Cognitive impairment is a serious complication of diabetes that manifests as an impairment of spatial memory and learning ability. Its pathogenesis is unclear, and effective therapeutic drugs are very limited. Our group designed and synthesized a novel compound named 3-p-tolyl-9H-xanthen-9-one (Tozan). In this study, we sought to investigate the effects and mechanism of Tozan on diabetic cognitive impairment.

Methods

Methylglyoxal (MG)-induced SH-SY5Y cells and streptozotocin (STZ)-induced type 1 diabetic mice were treated with Tozan. Methyl thiazolul tetrazolium (MTT) and lactate dehydrogenase (LDH) were used to test cytotoxicity. Morris water maze (MWM) and Y-maze tests were used to evaluate cognitive function. Immunofluorescence and western blot analyses were used to evaluate neurogenesis, apoptosis, and signal transduction pathway-related proteins. In addition, Lentivirus (LV)-estrogen receptor beta (ERβ)-ribonucleic acid interference (RNAi) was used to knockdown the ERβ gene in SH-SY5Y cells.

Results

We found that Tozan ameliorated MG-induced cytotoxicity in SH-SY5Y cells, improved cognitive dysfunction in STZ-induced type 1 diabetic mice, increased neurogenesis, and prevented apoptotic responses in vitro and in vivo. Importantly, Tozan (2, 4, and 8 mg/kg) mediated phosphatidylinositol-3-kinase and protein kinase B cAMP-response element binding protein (PI3K/Akt-CREB) signaling by activating membrane ERβ, and a high dose of Tozan (8 mg/kg) mediated CREB signaling by activating nuclear ERβ in the hippocampus. Notably, Tozan did not have an anti-apoptosis and regeneration protective role in ERβ gene knockdown cells.

Conclusions

Our study demonstrates Tozan’s contributions to and role in cognition, neurogenesis, and apoptosis in diabetes, and lays an experimental foundation for the development of new anti-diabetic cognitive impairment drugs.

Actinomycin V Induces Apoptosis Associated with Mitochondrial and PI3K/AKT Pathways in Human CRC Cells

Actinomycin (Act) V, an analogue of Act D, presented stronger antitumor activity and less hepatorenal toxicity than Act D in our previous studies, which is worthy of further investigation. We hereby report that Act V induces apoptosis via mitochondrial and PI3K/AKT pathways in colorectal cancer (CRC) cells. Act V-induced apoptosis was characterized by mitochondrial dysfunction, with loss of mitochondria membrane potential (MMP) and cytochrome c release, which then activated cleaved caspase-9, cleaved caspase-3, and cleaved PARP, revealing that it was related to the mitochondrial pathway, and the apoptotic trendency can be reversed by caspase inhibitor Z-VAD-FMK. Furthermore, we proved that Act V significantly inhibited PI3K/AKT signalling in HCT-116 cells using cell experiments in vitro, and it also presented a potential targeted PI3Kα inhibition using computer docking models. Further elucidation revealed that it exhibited a 28-fold greater potency than the PI3K inhibitor LY294002 on PI3K inhibition efficacy. Taken together, Act V, as a superior potential replacement of Act D, is a potential candidate for inhibiting the PI3K/AKT pathway and is worthy of more pre-clinical studies in the therapy of CRC.

Reproductive toxicity of cadmium in pubertal male rats induced by cell apoptosis

Cadmium (Cd) is a heavy metal that is widely present in modern industrial production. It is a known, highly toxic environmental endocrine disruptor. Long-term exposure to Cd can cause varying degrees of damage to the liver, kidney, and reproductive system of organisms, especially the male reproductive system. This study aimed to explore the mechanism of Cd toxicity in the male reproductive system during puberty. Eighteen healthy 6-week-old male Sprague-Dawley rats were randomly divided into three groups (control group, low-dose group, and high-dose group) according to their body weight, with six in each group. Cd (0, 1, and 3 mg/kg/day) was given by gavage for 28 consecutive days. The results showed that Cd exposure to each dose group caused a decrease in the testicular organ coefficient and sperm count, compared with the control group. Cd exposure resulted in significant changes in testicular morphology in the 3 mg/kg/day Cd group. In the 1 and 3 mg/kg/day Cd groups, serum testosterone decreased and apoptosis of testicular cells increased significantly (p < 0.05). In addition, compared with the control group, the activity of glutathione peroxidase and superoxide dismutase in each Cd exposure dose group decreased, but the content of malondialdehyde in the high-dose, 3 mg/kg/day Cd treatment group significantly increased (p < 0.05). Although Cd exposure caused an increase in the messenger RNA (mRNA) levels of Bcl-2, Caspase-3 and Caspase-9 in the testicular tissues (p < 0.05), Bcl-2 expression was unchanged (p > 0.05). The expression level of Akt mRNA in testicular tissue of rats in the high-dose 3 mg/kg/day Cd group was increased (p < 0.05). Our data suggest that Cd affected testosterone levels, and apoptosis was observed in spermatids.

Alogliptin: a novel approach against cyclophosphamide-induced hepatic injury via modulating SIRT1/FoxO1 pathway

Cyclophosphamide (CP) is one of the most potent alkylating agents and is widely used in the treatment of numerous neoplastic conditions, autoimmune diseases and following organ transplantation. Due to its ability to induce oxidative stress and subsequent apoptosis, CP is affiliated with many adverse effects with special emphasis on the highly prevalent hepatotoxicity. Dipeptidyl peptidase 4 (DDP-IV) inhibitors are being rediscovered for new biological effects due to their ability to target multiple pathways, among which is the phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt) axis. This could offer protection to multiple organs against reactive oxygen species (ROS) through modulating sirtuin 1 (SIRT1) expression and, in turn, inactivation of forkhead box transcription factor of the O class 1 (FoxO1), thus inhibiting apoptosis. Accordingly, the current study aimed to investigate the potential therapeutic benefit of alogliptin (Alo), a DPP-IV inhibitor, against CP-induced hepatotoxicity through enhancing PI3K/Akt/SIRT1 pathway. Forty male Wistar rats were randomly divided into four groups. The CP-treated group received a single dose of CP (200 mg/kg; i.p.). The Alo-treated group received Alo (20 mg/kg; p.o.) for 7 days with single CP injection on Day 2. Alo successfully reduced hepatic injury as witnessed through decreased liver function enzymes, increased phospho (p)-PI3K, p-Akt, superoxide dismutase (SOD) levels, SIRT1 expression, p-FoxO1 and anti-apoptotic B-cell lymphoma 2 (Bcl-2). This resulted in decreased apoptosis, as witnessed through decreased caspase-3 levels and improved histopathological picture. In conclusion, the current study succeeded to elaborate, for the first time, the promising impact of Alo in ameliorating chemotherapy-induced liver injury.

Misaligned foveal morphology and sector retinal dysfunction in AKT1-mosaic Proteus syndrome

PURPOSE

Proteus syndrome arises as a result of a post-zygotic mosaic activating mutation in the AKT1 oncogene, causing a disproportionate overgrowth of affected tissues. A small number of ocular complications have been reported. We present the unique findings in a patient who had molecular confirmation of AKT1 mosaicism alongside fulfilling the clinical criteria for Proteus syndrome.

METHODS

Pattern electroretinography, visual evoked potentials and multifocal electroretinography testing were performed alongside detailed retinal imaging and clinical examination to detail the ophthalmic characteristics.

RESULTS

Electrophysiological findings characterised unilateral macular dysfunction alongside sector retinal dysfunction of the right eye. This was demonstrated through optical coherence tomography and ultra-wide-field imaging to be associated with a misaligned foveal morphology and sector retinal dysfunction extending into the temporal retina.

CONCLUSION

We propose this patient has asymmetric foveal development and concomitant sector retinal dysfunction as the result of the mosaic AKT1 mutation, either through disruption in the retinal PI3K-AKT1 signalling pathway or through mechanical distortion of ocular growth, resulting in disproportionate inner retinal development. The findings expand the ocular phenotype of Proteus syndrome and encourage early assessment to identify any incipient ocular abnormalities.

A synthetic coumarin derivative (4-flourophenylacetamide-acetyl coumarin) impedes cell cycle at G0/G1 stage, induces apoptosis, and inhibits metastasis via ROS-mediated p53 and AKT signaling pathways in A549 cells

New chemotherapeutic agents with minimum side effects are indispensable to treat non-small-cell lung cancer (NSCLC) since the mortality rate of patients suffering from NSCLC remains high despite receiving conventional medication. In our previous study, many coumarin derivatives were screened for their anticancer properties in A549, an in vitro NSCLC model. One of these, 4-flourophenylacetamide-acetyl coumarin (4-FPAC), induced cytotoxicity at a concentration as low as 0.16 nM. Herein, initially, the cytotoxic potential of 4-FPAC was tested on a noncancerous cell line NIH3T3 and was found safe at the selected dose of 0.16 nM. Further, we investigated the mechanism by which 4-FPAC induced cytotoxicity and arrested the progression of cell cycle as well as metastasis in A549. Results of ethidium bromide/acridine orange (EtBr/AO), 4,6-diamidino-2-phenylindole, comet, and lactate dehydrogenase assays revealed that 4-FPAC caused cytotoxicity via reactive oxygen species-induced p53-mediated mechanism, which involves both extrinsic and intrinsic pathways of apoptosis. Dichlorodihydrofluorescein diacetate, rhodamine 123, and AO staining confirmed the involvement of both mitochondria and lysosome in inducing apoptosis. However, flow cytometric analysis revealed that it causes cell cycle arrest at the G0/G1 phase by modulating p21, CDK2, and CDK4 expression. Aggregation, soft-agar, clonogenic, and scratch assays as well as gene expression analysis collectively confirmed that 4-FPAC minimizes the metastatic property of A549 by downregulating Snail, matrix metalloproteinase 9, and interleukin-8. Additional studies reaffirmed the above findings and substantiated the role of PI3K/AKT in achieving them. The cell-type-specific selective cytostatic and antimetastatic properties shown by 4-FPAC indicate its potential to emerge as a drug of choice against NSCLC in the future.

Hypoxia induces tumor cell growth and angiogenesis in non-small cell lung carcinoma via the Akt-PDK1-HIF1α-YKL-40 pathway

BACKGROUND

As one of the most common forms of cancer, non-small cell lung carcinoma (NSCLC), is characterized by oxygen deprivation (hypoxia). The transcription factor hypoxia-inducible factor (HIF)-1α is a major mediator which responds hypoxia and regulates many contributing factors. The various modes of hypoxia regulation are frequently the focus of research studies. With reference to previous published research, we hypothesized that hypoxia promotes the growth and angiogenesis of NSCLC via the Akt-PDK1-HIF1α-YKL-40 pathway, and verified it.

METHODS

We mainly investigated changes in related factor expression between differently treated CL1-5 cells. We carried out overexpression and underexpression transfection, Western blot, rt-PCR and ELISA, and observed cellular biological behaviors by CCK-8 migration and invasion assay, and tube formation assay.

RESULTS

A hypoxic environment significantly increased the phosphorylation of Akt and PDK1 in mitochondria. The hypoxia-induced accumulation of p-Akt in mitochondria activated PDK1 phosphorylation, promoted the expression of HIF1α, and the expression of YKL-40. The overexpression of YKL-40 promoted the proliferation, migration, invasion and tubule formation of CL1-5 cells.

CONCLUSIONS

A hypoxic tumor microenvironment can promote the expansion and angiogenesis of NSCLC cells through the Akt-PDK1-HIF1α-YKL-40 pathway. This may provide a new mechanism and potential interventional target for anti-vascular lung cancer therapy.

Dexmedetomidine Improves Cardiovascular and Ventilatory Outcomes in Critically Ill Patients: Basic and Clinical Approaches

Dexmedetomidine (DEX) is a highly selective α2-adrenergic agonist with sedative and analgesic properties, with minimal respiratory effects. It is used as a sedative in the intensive care unit and the operating room. The opioid-sparing effect and the absence of respiratory effects make dexmedetomidine an attractive adjuvant drug for anesthesia in obese patients who are at an increased risk for postoperative respiratory complications. The pharmacodynamic effects on the cardiovascular system are known; however the mechanisms that induce cardioprotection are still under study. Regarding the pharmacokinetics properties, this drug is extensively metabolized in the liver by the uridine diphosphate glucuronosyltransferases. It has a relatively high hepatic extraction ratio, and therefore, its metabolism is dependent on liver blood flow. This review shows, from a basic clinical approach, the evidence supporting the use of dexmedetomidine in different settings, from its use in animal models of ischemia-reperfusion, and cardioprotective signaling pathways. In addition, pharmacokinetics and pharmacodynamics studies in obese subjects and the management of patients subjected to mechanical ventilation are described. Moreover, the clinical efficacy of delirium incidence in patients with indication of non-invasive ventilation is shown. Finally, the available evidence from DEX is described by a group of Chilean pharmacologists and clinicians who have worked for more than 10 years on DEX.

Silencing of soluble epoxide hydrolase 2 gene reduces H2O2-induced oxidative damage in rat intestinal epithelial IEC-6 cells via activating PI3K/Akt/GSK3β signaling pathway

Oxidative stress plays a vital role in the occurrence and development of intestinal injury. Soluble epoxide hydrolase 2 gene (EPHX2) is a class of hydrolytic enzymes. We aim to explore the effects and molecular mechanism of siEPHX2 on H2O2-induced oxidative damage in rat intestinal epithelial IEC-6 cells. IEC-6 cells were transfected with EPHX2-siRNA and control si RNA plasmids by lipofectamine™ 2000 transfection reagent. The transfected samples were treated with H2O2 (50, 100, 200, 300, 400, and 500 µmol/L) for 12, 24, and 48 h, respectively. Cell viability was determined by cell counting kit-8 (CCK-8). Lactate dehydrogenase (LDH), malondialdehyde (MDA), and superoxide dismutase (SOD) were assessed by respective detection kits. Mitochondrial membrane potential (MMP), cell apoptosis and reactive oxygen species (ROS) and the levels of factors were determined by flow cytometer, quantitative real-time PCR (qRT-PCR) and western blot assays, respectively. We found that the IC50 of H2O2 was 200 µmol/L at 24 h, and the transfection of siEHPX2 in H2O2-induced IEC-6 cells significantly promoted the cell viability, SOD activity and MMP rate, and reduced the rates of ROS and apoptosis as well as LDH and MDA contents. siEHPX2 up-regulated the B-cell lymphoma-2 (Bcl-2) level and down-regulated the levels of fibroblast-associated (Fas), Fas ligand (Fasl), Bcl-2 associated X protein (Bax), and Caspase-3. Moreover, the phosphorylation levels of phosphoinositide 3 kinase (PI3K), protein kinase B (Akt), and glycogen synthase kinase3β (GSK3β) were up-regulated. We proved that siEPHX2 had a protective effect on H2O2-induced oxidative damage in IEC-6 cells through activating PI3K/Akt/GSK3β signaling pathway.

Dexmedetomidine protects against sepsis‑associated encephalopathy through Hsp90/AKT signaling

Sepsis‑associated encephalopathy (SAE) is characterized by neuronal apoptosis and changes in mental status. Accumulating evidence has. indicated that dexmedetomidine is capable of protecting the brain against external stimuli and improving cognitive dysfunctions. The aim of the present study was to investigate the possible neuroprotective effects of dexmedetomidine on SAE and the role of heat‑shock protein (Hsp)90/AKT signaling in an experimental model of sepsis. The SAE model was established by cecal ligation and perforation (CLP) in vivo and lipopolysaccharide (LPS) treated hippocampal neuronal cultures in vitro. It was found that dexmedetomidine inhibited caspase‑3, but increased the expression level ofBcl‑2 in CLP rats. CLP rats also exhibited a decreased level of phosphorylated AKT Thr 308 and Hsp90, and their expression could be reversed by treatment with dexmedetomidine. Additionally, application of dexmedetomidine increased cell survival and decreased neuronal apoptosis in vitro. Furthermore, the neuroprotective effects of dexmedetomidine could be reversed by 17‑AAG (a Hsp90 inhibitor), or wortmannin (a PI3K inhibitor). Analysis of TUNEL staining indicated that dexmedetomidine improved LPS‑induced neuronal apoptosis, which could be eradicated by AKT short hairpin RNA transfection, prazosin or yohimbine. Finally, dexmedetomidine ameliorated both the emotional and spatial cognitive disorders without alteration in locomotor activity. The present findings suggested that dexmedetomidine may protect the brain against SAE, and that the Hsp90/AKT pathway may be involved in this process.

RITA induces apoptosis in p53-null K562 leukemia cells by inhibiting STAT5, Akt, and NF-κB signaling pathways

Targeting oncogenic signaling pathways by small molecules has emerged as a potential treatment strategy for cancer. reactivation of p53 and induction of tumor cell apoptosis (RITA) is a promising anticancer small molecule that reactivates p53 and induces exclusive apoptosis in tumor cells. Less well appreciated was the possible effect of small molecule RITA on p53-null leukemia cells. In this study, we demonstrated that RITA has potent antileukemic properties against p53-null chronic myeloid leukemia (CML)-derived K562 cells. RITA triggered apoptosis through caspase-9 and caspase-3 activation and poly (ADP-ribose) polymerase cleavage. RITA decreased STAT5 tyrosine phosphorylation, although it did not inhibit phosphorylation of the direct BCR-ABL substrate CrkL. Real-time PCR analysis showed that RITA downregulates antiapoptotic STAT5 target genes Bcl-xL and MCL-1. The downregulation of nuclear factor-κB (NF-κB), as evidenced by inhibition of IκB-α phosphorylation and its degradation, was associated with inhibition of Akt phosphorylation in RITA-treated cells. Furthermore, consistent with the decrease of mRNA levels, protein levels of the nuclear factor-κB-regulated antiapoptotic (cIAP1, XIAP, and Bcl-2) and proliferative (c-Myc) genes were downregulated by RITA in K562 cells. In conclusion, the ability of RITA to inhibit prosurvival signaling pathways in CML cells suggests a potential application of RITA in CML therapeutic protocols.

GALECTIN-8 Is a Neuroprotective Factor in the Brain that Can Be Neutralized by Human Autoantibodies

Galectin-8 (Gal-8) is a glycan-binding protein that modulates a variety of cellular processes interacting with cell surface glycoproteins. Neutralizing anti-Gal-8 antibodies that block Gal-8 functions have been described in autoimmune and inflammatory disorders, likely playing pathogenic roles. In the brain, Gal-8 is highly expressed in the choroid plexus and accordingly has been detected in human cerebrospinal fluid. It protects against central nervous system autoimmune damage through its immune-suppressive potential. Whether Gal-8 plays a direct role upon neurons remains unknown. Here, we show that Gal-8 protects hippocampal neurons in primary culture against damaging conditions such as nutrient deprivation, glutamate-induced excitotoxicity, hydrogen peroxide (H₂O₂)-induced oxidative stress, and β-amyloid oligomers (Aβo). This protective action is manifested even after 2 h of exposure to the harmful condition. Pull-down assays demonstrate binding of Gal-8 to selected β1-integrins, including α3 and α5β1. Furthermore, Gal-8 activates β1-integrins, ERK1/2, and PI3K/AKT signaling pathways that mediate neuroprotection. Hippocampal neurons in primary culture produce and secrete Gal-8, and their survival decreases upon incubation with human function-blocking Gal-8 autoantibodies obtained from lupus patients. Despite the low levels of Gal-8 expression detected by real-time PCR in hippocampus, compared with other brain regions, the complete lack of Gal-8 in Gal-8 KO mice determines higher levels of apoptosis upon H₂O₂ stereotaxic injection in this region. Therefore, endogenous Gal-8 likely contributes to generate a neuroprotective environment in the brain, which might be eventually counteracted by human function-blocking autoantibodies.

Anti-liver cancer effect and the mechanism of arsenic sulfide in vitro and in vivo

PURPOSE

This study aimed at investigating the anti-tumor effect of arsenic sulfide (As₂S₂) against liver cancer both in vivo and in vitro and to elucidate its underlying mechanisms.

METHODS

Cell viability of the human hepatocellular carcinoma cell lines SMMC-7721, BEL-7402, HepG2 were measured by CCK-8 assay. The effects of As₂S₂ on cell proliferation and apoptosis of SMMC-7721 cells were investigated using Calcein-AM and PI staining, Hoechst 33258 staining, crystal violet staining, and JC-1 staining. Cell cycle and Annexin V/PI assay were analyzed via flow cytometry. The expression of apoptosis-related proteins, phosphorylation of PI3K and AKT were detected by Western blotting. H22-bearing mice model was established to evaluate the anti-tumor effect of As₂S₂ in vivo. HE staining, PCNA was observed via immunohistochemistry, and TUNEL assay was used to assess the anti-proliferation and pro-apoptotic effects of As₂S₂.

RESULTS

As₂S₂ significantly inhibited the growth of human hepatoma cells SMMC-7721, BEL-7402 and HepG2. As₂S₂ inhibited cell proliferation effectively by inducing G0/G1 cell cycle arrest in SMMC-7721 cells. As₂S₂ could increase Bax/Bcl-2 ratio, decrease mitochondrial membrane potential, promote the release of cytochrome c, increase the levels of cleaved caspase-3 and PARP, indicating that As₂S₂ induced apoptosis in SMMC-7721 cells via mitochondrial-mediated apoptosis pathway. Further research showed that As₂S₂ inhibited the PI3K/AKT signaling pathway leading to apoptotic cell death. In addition, As₂S₂ significantly inhibited tumor growth in H22-bearing mice and induced apoptosis by deactivating PI3K/AKT pathway, which was consistent with the in vitro results.

CONCLUSION

These findings suggested that As₂S₂ could induce apoptosis of liver cancer cells in vitro and in vivo, which was related to PI3K/AKT-mediated mitochondrial pathway and may provide a novel promising therapeutic agent for liver cancer treatment.

Orthognathic surgery induces genomewide changes longitudinally in DNA methylation in saliva

OBJECTIVE

Orthognathic surgery dramatically changes morphology of the maxillofacial deformity and improves the malocclusion morphologically and functionally. We investigated the influence of orthognathic surgery on genomewide DNA methylation in saliva.

METHODS

Saliva was obtained from nine patients undergoing orthognathic surgery and two healthy reference individuals before and 3 months after orthognathic surgery. Genomewide DNA methylation profiling of saliva (341,482 CpG dinucleotides) was conducted using Infinium HumanMethylation450 BeadChips.

RESULTS

Comparison between pre- and postsurgery saliva samples revealed significant changes in DNA methylation patterns at 2,381 CpG sites (p < 0.01) with suggestive significance. The differentially methylated probe sets were significantly associated with the cancer pathway (p = 2.8 × 10^-7 ; a false discovery rate q-value = 3.7 × 10^-4 ) and PI3K-Akt signalling pathway (p = 2.4 × 10^-5 ; a false discovery rate q-value = 3.1 × 10^-2 ).

CONCLUSION

Pathway enrichment analysis of genes with suggestive significance demonstrated that altered DNA methylation in saliva of patients undergoing orthognathic surgery, possibly as a response to surgical stress or bone injury. Further studies with a large sample size and long-term observation are needed to validate the phenomena identified in this study.

ERα and/or ERβ activation ameliorates cognitive impairment, neurogenesis and apoptosis in type 2 diabetes mellitus mice

Estrogen receptors (ERs) are thought to be associated with the onset and progression of neurodegenerative injuries and diseases, but the relationship and mechanisms underlying between ERs and cognition in type 2 diabetes remain elusive. In the current study, we investigated the effects of ERα and ERβ on the cognition, neurogenesis and apoptosis in high-fat diet and streptozocin-induced diabetic mice. We found that ERα and/or ERβ activation using their agonists (0.5 mg/kg E2, PPT or DPN) ameliorate memory impairment in the Morris water maze and Y-maze tests, increase hippocampal neurogenesis and prevent hippocampal apoptotic responses. Importantly, treatment with the pharmacologic ERs agonists caused significant increases in the membrane ERα and ERβ expression and subsequent PI3K/Akt, CREB and BDNF activation in the hippocampus of type 2 diabetes mellitus mice. Our data indicate that ERα and ERβ are involved in the cognitive impairment in type 2 diabetes, and that activated ERs, such as application of ERs agonists, could be a novel and promising strategy for the treatment of diabetic cognitive impairment.

Activation of ERα and/or ERβ ameliorates cognitive impairment and apoptosis in streptozotocin-induced diabetic mice

Estrogen receptors (ERs) are thought to be associated with the onset and progression of neurodegenerative injuries and diseases, but the relationship and mechanisms underlying between ERs and cognition in type 1 diabetes remain elusive. In the current study, we investigated the effects of ERα and ERβ on the memory impairment and apoptosis in streptozotocin-induced diabetic mice. We found that ERα and/or ERβ activation using their agonists (0.5 mg/kg E2, PPT or DPN) ameliorate memory impairment in the Morris water maze (MWM) and Y-maze tests and suppress apoptosis as evidenced by decreased caspase-3 activity and increased ratio of Bcl-2/Bax. Importantly, treatment with the pharmacologic ERs agonists caused significant increases in the membrane ERα and ERβ expression and subsequent PI3K/Akt, CREB and BDNF activation in the hippocampus of diabetic mice. Our data indicate that ERα and ERβ are involved in the cognitive impairment of type 1 diabetes and that activation of ERs via administration of ERs agonists could be a novel and promising strategy for the treatment of diabetic cognitive impairment.

The protective effects of total paeony glycoside on ischemia/reperfusion injury in H9C2 cells via inhibition of the PI3K/Akt signaling pathway

At present, cardiovascular disease is the global leading cause of mortality. Total paeony glycoside (TPG) is a traditional Chinese medicine, which serves a pivotal role in the cardiovascular system. In the present study, the effects and underlying mechanisms of TPG on ischemia/reperfusion (I/R) injury-induced apoptosis of cardiomyocytes were investigated in vitro. Cell Counting kit-8 and flow cytometry were used to assess the viability, reactive oxygen species (ROS) content and apoptosis of H9C2 cells. The activities of lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPX) were analyzed by commercial detection kits. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were conducted to evaluate the expression levels of various factors. The results demonstrated that the viability of H9C2 cells was not significantly altered in response to various concentrations of TPG. However, following I/R injury, TPG markedly enhanced cell viability in a time- and dose-dependent manner. Furthermore, TPG decreased the rate of apoptosis and ROS levels, and reduced the activities of MDA and LDH. Conversely, TPG increased SOD and GPX activities. In addition, TPG upregulated the expression levels of pro-caspase-3 and B-cell lymphoma2 (Bcl-2), whereas it downregulated cleaved-caspase-3, poly (ADP-ribose) polymerase 1, Bcl-2-associated X protein, phosphorylated (p)-phosphatidylinositol 3 kinase (PI3K) and p-protein kinase B (Akt) expression. Treatment with insulin-like growth factor-1 increased the apoptosis of H9C2 cells, thus suggesting that activation of the PI3K/Akt signaling pathway reversed the protective effects of TPG. Taken together, TPG may suppress I/R-induced apoptosis and oxidative stress of H9C2 cells possibly by inhibiting the PI3K/Akt signaling pathway; such a phenomenon may have a therapeutic effect on cardiovascular disease.

Sex steroid hormones as neuroprotective elements in ischemia models

Among sex steroid hormones, progesterone and estradiol have a wide diversity of physiological activities that target the nervous system. Not only are they carried by the blood stream, but also they are locally synthesized in the brain and for this reason, estradiol and progesterone are considered 'neurosteroids'. The physiological actions of both hormones range from brain development and neurotransmission to aging, illustrating the importance of a deep understanding of their mechanisms of action. In this review, we summarize key roles that estradiol and progesterone play in the brain. As numerous reports have confirmed a substantial neuroprotective role for estradiol in models of neurodegenerative disease, we focus this review on traumatic brain injury and stroke models. We describe updated data from receptor and signaling events triggered by both hormones, with an emphasis on the mechanisms that have been reported as 'rapid' or 'cytoplasmic actions'. Data showing the therapeutic effects of the hormones, used alone or in combination, are also summarized, with a focus on rodent models of middle cerebral artery occlusion (MCAO). Finally, we draw attention to evidence that neuroprotection by both hormones might be due to a combination of 'cytoplasmic' and 'nuclear' signaling.

Inhibitory effect of PDGF-BB and serum-stimulated responses in vascular smooth muscle cell proliferation by hinokitiol via up-regulation of p21 and p53

INTRODUCTION

Vascular smooth muscle cell (VSMC) proliferation plays a major role in the progression of vascular diseases. In the present study, we established the efficacy and the mechanisms of action of hinokitiol, a tropolone derivative found in Chamaecyparis taiwanensis, Cupressaceae, in relation to platelet-derived growth factor-BB (PDGF-BB) and serum-dependent VSMC proliferation.

MATERIAL AND METHODS

Primary cultured rat VSMCs were pre-treated with hinokitiol and then stimulated by PDGF-BB (10 ng/ml) or serum (10% fetal bovine serum). Cell proliferation and cytotoxicity were determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and lactose dehydrogenase assay, respectively. The degree of DNA synthesis was evaluated by BrdU-incorporation measurements and observed using confocal microscopy. Immunoblotting was utilized to determine the protein level of p-extracellular signal-regulated kinase (ERK) 1/2, p-Akt, p-phosphoinositide 3-kinase (PI3K), p-Janus kinase 2 (JAK2), p-p53, and p21^Cip1. The promoter activity of p21 and p53 activity were measured by dual luciferase reporter assay.

RESULTS

Treatment with hinokitiol (1-10 μM) inhibited PDGF-BB and serum-induced VSMC proliferation and DNA synthesis in a concentration-dependent manner. Cytotoxicity was not observed in hinokitiol-treated VSMCs at the studied concentrations. Pre-incubation of VSMCs with hinokitiol did not alter PDGF-BB-induced phosphorylation of ERK1/2, Akt, PI3K or JAK2. Interestingly, hinokitiol induced promoter activity of p21 and p21 protein expression in VSMCs. Furthermore, hinokitiol augmented p53 protein phosphorylation and subsequently led to enhanced p53 activity.

CONCLUSIONS

These data suggest that the anti-proliferative effects of hinokitiol in VSMCs may be mediated by activation of p21 and p53 signaling pathways, and it may contribute to the prevention of vascular diseases associated with VSMC proliferation.

Treadmill exercise activates PI3K/Akt signaling pathway leading to GSK-3β inhibition in the social isolated rat pups

Social isolation is known to precipitate depression-like symptoms in rodents and has emerged as a dependable paradigm to screen the behavioral and neurobiological changes observed in humans. In the present study, the undying mechanisms of treadmill exercise on social isolation-induced depression was evaluated. The rat pups in the social isolation groups were housed individually. The social isolation procedures started on the postnatal day 14. The rat pups in the exercise groups were forced to run on treadmill for 30 min once a day from postnatal day 21 to postnatal day 34. The expression of phosphoinositide 3 kinase (PI3K), tyrosine kinase B (Akt), and glycogen synthase kinase 3β (GSK-3β) in the hippocampus were determined by using western blot analysis. The ratio phosphorylated PI3K (p-PI3K)/PI3K and phosphorylated Akt (p-Akt)/Akt were decreased and the ratio of phosphorylated-GSK-3 (p-GSK-3β)/GSK-3β was increased by social isolation. Treadmill exercise increased the ratio p-PI3K/PI3K and p-Akt/Akt and suppressed the ratio of p-GSK-3β/GSK-3β in the hippocampus of social isolated rat pups. Treadmill exercise activates PI3K/Akt signaling pathway leading to GSK-3β inhibition in social isolated rats. These results suggested that treadmill exercise may improve depressive symptoms via activation of PI3K/Akt signaling pathway.

Systems pharmacological analysis of mitochondrial cardiotoxicity induced by selected tyrosine kinase inhibitors

Tyrosine kinase inhibitors (TKIs) are targeted therapies rapidly becoming favored over conventional cytotoxic chemotherapeutics. Our study investigates two FDA approved TKIs, DASATINIB; indicated for IMATINIB-refractory chronic myeloid leukemia, and SORAFENIB; indicated for hepatocellular carcinoma and advanced renal cell carcinoma. Limited but crucial evidence suggests that these agents can have cardiotoxic side effects ranging from hypertension to heart failure. A greater understanding of the underlying mechanisms of this cardiotoxicity are needed as concerns grow and the capacity to anticipate them is lacking. The objective of this study was to explore the mitochondrial-mediated cardiotoxic mechanisms of the two selected TKIs. This was achieved experimentally using immortalized human cardiomyocytes, AC16 cells, to investigate dose- and time-dependent cell killing, along with measurements of temporal changes in key signaling proteins involved in the intrinsic apoptotic and autophagy pathways upon exposure to these agents. Quantitative systems pharmacology (QSP) models were developed to capture the toxicological response in AC16 cells using protein dynamic data. The developed QSP models captured well all the various trends in protein signaling and cellular responses with good precision on the parameter estimates, and were successfully qualified using external data sets. An interplay between the apoptotic and autophagic pathways was identified to play a major role in determining toxicity associated with the investigated TKIs. The established modeling platform showed utility in elucidating the mechanisms of cardiotoxicity of SORAFENIB and DASATINIB. It may be useful for other small molecule targeted therapies demonstrating cardiac toxicities, and may aid in informing alternate dosing strategies to alleviate cardiotoxicity associated with these therapies.

Crosstalk between the IGF-1R/AKT/mTORC1 pathway and the tumor suppressors p53 and p27 determines cisplatin sensitivity and limits the effectiveness of an IGF-1R pathway inhibitor

The insulin-like growth factor-1 receptor (IGF-1R) signaling pathway is aberrantly activated in multiple cancers and can promote proliferation and chemotherapy resistance. Multiple IGF-1R inhibitors have been developed as potential therapeutics. However, these inhibitors have failed to increase patient survival when given alone or in combination with chemotherapy agents. The reason(s) for the disappointing clinical effect of these inhibitors is not fully understood. Cisplatin (CP) activated the IGF-1R/AKT/mTORC1 pathway and stabilized p53 in osteosarcoma (OS) cells. p53 knockdown reduced IGF-1R/AKT/mTORC1 activation by CP, and IGF-1R inhibition reduced the accumulation of p53. These data demonstrate positive crosstalk between p53 and the IGF-1R/AKT/mTORC1 pathway in response to CP. Further studies showed the effect of IGF-1R inhibition on CP response is dependent on p53 status. In p53 wild-type cells treated with CP, IGF-1R inhibition increased p53s apoptotic function but reduced p53-dependent senescence, and had no effect on long term survival. In contrast, in p53-null/knockdown cells, IGF-1R inhibition reduced apoptosis in response to CP and increased long term survival. These effects were due to p27 since IGF-1R inhibition stabilized p27 in CP-treated cells, and p27 depletion restored apoptosis and reduced long term survival. Together, the results demonstrate 1) p53 expression determines the effect of IGF-1R inhibition on cancer cell CP response, and 2) crosstalk between the IGF-1R/AKT/mTORC1 pathway and p53 and p27 can reduce cancer cell responsiveness to chemotherapy and may ultimately limit the effectiveness of IGF-1R pathway inhibitors in the clinic.

Ketamine, a Clinically Used Anesthetic, Inhibits Vascular Smooth Muscle Cell Proliferation via PP2A-Activated PI3K/Akt/ERK Inhibition

Abnormal proliferation of vascular smooth muscle cells (VSMCs) gives rise to major pathological processes involved in the development of cardiovascular diseases. The use of anti-proliferative agents for VSMCs offers potential for the treatment of vascular disorders. Intravenous anesthetics are firmly established to have direct effects on VSMCs, resulting in modulation of blood pressure. Ketamine has been used for many years in the intensive care unit (ICU) for sedation, and has recently been considered for adjunctive therapy. In the present study, we investigated the effects of ketamine on platelet-derived growth factor BB (PDGF-BB)-induced VSMC proliferation and the associated mechanism. Ketamine concentration-dependently inhibited PDGF-BB-induced VSMC proliferation without cytotoxicity, and phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated protein kinase (ERK) inhibitors, LY294002 and PD98059, respectively, have similar inhibitory effects. Ketamine was shown to attenuate PI3K, Akt, and ERK1/2 phosphorylation induced by PDGF-BB. Okadaic acid, a selective protein phosphatase 2A (PP2A) inhibitor, significantly reversed ketamine-mediated PDGF-BB-induced PI3K, Akt, and ERK1/2 phosphorylation; a transfected protein phosphatse 2a (pp2a) siRNA reversed Akt and ERK1/2 phosphorylation; and 3-O-Methyl-sphingomyeline (3-OME), an inhibitor of sphingomyelinase, also significantly reversed ERK1/2 phosphorylation. Moreover, ketamine alone significantly inhibited tyrosine phosphorylation and demethylation of PP2A in a concentration-dependent manner. In addition, the pp2a siRNA potently reversed the ketamine-activated catalytic subunit (PP2A-C) of PP2A. These results provide evidence of an anti-proliferating effect of ketamine in VSMCs, showing activation of PP2A blocks PI3K, Akt, and ERK phosphorylation that subsequently inhibits the proliferation of VSMCs. Thus, ketamine may be considered a potential effective therapeutic agent for reducing atherosclerotic process by blocking the proliferation of VSMCs.

The IGF-1R/AKT pathway has opposing effects on Nutlin-3a-induced apoptosis

Nutlin-3a is a small molecule MDM2 antagonist and potent activator of wild-type p53. Nutlin-3a disrupts MDM2 binding to p53, thus increasing p53 levels and allowing p53 to inhibit proliferation or induce cell death. Factors that control sensitivity to Nutlin-3a-induced apoptosis are incompletely understood. In this study we isolated cisplatin-resistant clones from MHM cells, an MDM2-amplified and p53 wild-type osteosarcoma cell line. Cisplatin resistance in these clones resulted in part from heightened activation of the IGF-1R/AKT pathway. Interestingly, these cisplatin resistant clones showed hyper-sensitivity to Nutlin-3a induced apoptosis. Increased Nutlin-3a sensitivity was associated with reduced authophagy flux and a greater increase in p53 levels in response to Nutlin-3a treatment. IGF-1R and AKT inhibitors further increased apoptosis by Nutlin-3a in parental MHM cells and the cisplatin-resistant clones, confirming IGF-1R/AKT signaling promotes apoptosis resistance. However, IGF-1R and AKT inhibitors also reduced p53 accumulation in Nutlin-3a treated cells and increased autophagy flux, which we showed can promote apoptosis resistance. We conclude the IGF-1R/AKT pathway has opposing effects on Nutlin-3a-induced apoptosis. First, it can inhibit apoptosis, consistent with its well-established role as a survival-signaling pathway. Second, it can enhance Nutlin-3a induced apoptosis through a combination of maintaining p53 levels and inhibiting pro-survival autophagy.

Protective effects of the neurosteroid allopregnanolone in a mouse model of spontaneous motoneuron degeneration

Amyotrophic lateral sclerosis (ALS) is a devastating disorder characterized by progressive death of motoneurons. The Wobbler (WR) mouse is a preclinical model sharing neuropathological similarities with human ALS. We have shown that progesterone (PROG) prevents the progression of motoneuron degeneration. We now studied if allopregnanolone (ALLO), a reduced metabolite of PROG endowed with gabaergic activity, also prevents WR neuropathology. Sixty-day old WRs remained untreated or received two steroid treatment regimens in order to evaluate the response of several parameters during early or prolonged steroid administration. ALLO was administered s.c. daily for 5days (4mg/kg) or every other day for 32days (3, 3mg/kg), while another group of WRs received a 20mg PROG pellet s.c. for 18 or 60days. ALLO administration to WRs increased ALLO serum levels without changing PROG and 5 alpha dihydroprogesterone (5α-DHP), whereas PROG treatment increased PROG, 5α-DHP and ALLO. Untreated WRs showed higher basal levels of serum 5α-DHP than controls. In the cervical spinal cord we studied markers of oxidative stress or associated to trophic responses. These included nitric oxide synthase (NOS) activity, motoneuron vacuolation, MnSOD immunoreactivity (IR), brain derived neurotrophic factor (BDNF) and TrkB mRNAs, p75 neurotrophin receptor (p75NTR) and, cell survival or death signals such as pAKT and the stress activated kinase JNK. Untreated WRs showed a reduction of MnSOD-IR and BDNF/TrkB mRNAs, associated to high p75NTR in motoneurons, neuronal and glial NOS hyperactivity and neuronal vacuolation. Also, low pAKT, mainly in young WRs, and a high pJNK in the old stage characterized WŔs spinal cord. Except for MnSOD and BDNF, these alterations were prevented by an acute ALLO treatment, while short-term PROG elevated MnSOD. Moreover, after chronic administration both steroids enhanced MnSOD-IR and BDNF mRNA, while attenuated pJNK and NOS in glial cells. Long-term PROG also increased pAKT and reduced neuronal NOS, parameters not modulated by chronic ALLO. Clinically, both steroids improved muscle performance. Thus, ALLO was able to reduce neuropathology in this model. Since high oxidative stress activates p75NTR and pJNK in neurodegeneration, steroid reduction of these molecules may provide adequate neuroprotection. These data yield the first evidence that ALLO, a gabaergic neuroactive steroid, brings neuroprotection in a model of motoneuron degeneration.

Cordycepin induces apoptosis in human bladder cancer cells via activation of A3 adenosine receptors

Bladder cancer is a neoplasm originated from bladder epithelial cells. The therapy for bladder cancer is so far not satisfactory. In this study, we examined the effects of Cordyceps militaris hot water extracts containing cordycepin on human bladder cells. Cordyceps militaris hot water extracts containing cordycepin was used to treat human T24 bladder carcinoma cells, and we found that Cordyceps militaris hot water extracts containing cordycepin decreased T24 cell survival in a dose-dependent manner, which was seemingly mediated by activation of A3 adenosine receptor and the subsequent inactivation of Akt pathways, resulting in increases in cleaved Caspase-3 and apoptosis. Overexpression of A3 adenosine receptor in T24 cells mimicked the effects of Cordyceps militaris hot water extracts, while A3 adenosine receptor depletion abolished the effects of Cordyceps militaris hot water extracts containing cordycepin. Together, these data suggest that Cordyceps militaris hot water extracts containing cordycepin may be a promising treatment for bladder cancer via A3 adenosine receptor activation.

Up-regulation of Vps4A promotes neuronal apoptosis after intracerebral hemorrhage in adult rats

Vps4, vacuolar protein sorting 4, belongs to ATPases Associated with diverse cellular Activities (AAA) protein family which is made up of Vps4A and Vps4B. Previous studies demonstrated that Vps4A plays vital roles in diverse aspects such as virus budding, the efficient transport of H-Ras to the PM (plasma membrane) and the involvement in the MVB (multivesiculate bodies) pathway. Interestingly, Vps4A is also expressed in the brain. However, the distribution and function of Vps4A in ICH diseases remain unclear. In this study, we show that Vps4A may be involved in neuronal apoptosis during pathophysiological processes of intracerebral hemorrhage (ICH). Based on the results of Western blot and immunohistochemistry, we found a remarkable up-regulation of Vps4A expression surrounding the hematoma after ICH. Double labeled immunofluorescence showed that Vps4A was co-expressed with NeuN but rarely with astrocytes and microglia. Morever, we detected that neuronal apoptosis marker active caspase-3 had co-localizations with Vps4A. Additionaly, Vps4A knockdown in vitro specifically leads to decreasing neuronal apoptosis coupled with increased Akt phosphorylation. All datas suggested that Vps4A was involved in promoting neuronal apoptosis via inhibiting Akt phosphorylation after ICH.

Noninvasive Bioluminescence Imaging of AKT Kinase Activity in Subcutaneous and Orthotopic NSCLC Xenografts: Correlation of AKT Activity with Tumor Growth Kinetics

Aberrant signaling through the AKT kinase mediates oncogenic phenotypes including cell proliferation, survival, and therapeutic resistance. Here, we utilize a bioluminescence reporter for AKT kinase activity (BAR) to noninvasively assess the therapeutic efficacy of the EGFR inhibitor erlotinib in KRAS-mutated lung cancer therapy. A549 non–small cell lung cancer cell line, engineered to express BAR, enabled the evaluation of compounds targeting the EGFR/PI3K/AKT pathway in vitro as well as in mouse models. We found that erlotinib treatment of resistant A549 subcutaneous and orthotopic xenografts resulted in significant AKT inhibition as determined by an 8- to 13-fold (P < .0001) increase in reporter activity 3 hours after erlotinib (100 mg/kg) administration compared to the control. This was confirmed by a 25% (P < .0001) decrease in pAKT ex vivo and a decrease in tumor growth. Treatment of the orthotopic xenograft with varying doses of erlotinib (25, 50, and 100 mg/kg) revealed a dose- and time-dependent increase in reporter activity (10-, 12-, and 23-fold). Correspondingly, a decrease in phospho-AKT levels (0%, 16%, and 28%, respectively) and a decrease in the AKT dependent proliferation marker PCNA (0%, 50%, and 50%) were observed. We applied μ-CT imaging for noninvasive longitudinal quantification of lung tumor load which revealed a corresponding decrease in tumor growth in a dose-dependent manner. These findings demonstrate the utility of BAR to noninvasively monitor AKT activity in preclinical studies in response to AKT modulating agents. These results also demonstrate that BAR can be applied to study drug dosing, drug combinations, and treatment efficacy in orthotopic mouse lung tumor models.

Fis1 depletion in osteoarthritis impairs chondrocyte survival and peroxisomal and lysosomal function

Cumulative evidence suggests the importance of organelle homeostasis in regulating metabolic functions in response to various cellular stresses. Particularly, the dynamism and health of the mitochondria-peroxisome network through fission and fusion are essential for cellular function; dysfunctional dynamism underlies the pathogenesis of several degenerative diseases including Parkinson's disease. Here, we investigated the role of Fis1 in cartilage homeostasis and its relevance to osteoarthritis (OA). We found that Fis1 is significantly suppressed in human OA chondrocytes compared to that in normal chondrocytes. Fis1 depletion through siRNA induced peroxisomal dysfunction. Moreover, Fis1 suppression altered miRNA profiles, especially those implicated in lysosomal regulation. Lysosomal destruction using LAMP-1-specific targeted nanorods or lysosomal dysfunction through chloroquine treatment resulted in enhanced chondrocyte apoptosis and/or suppression of autophagy. Accordingly, lysosomal activity and autophagy were severely decreased in OA chondrocytes despite abundant LAMP-1-positive organelles. Moreover, Fis1 morpholino-injected zebrafish embryos displayed lysosome accumulation, mitochondrial dysfunction, and peroxisome reduction. Collectively, these data suggest interconnected links among Fis1-modulated miRNA, lysosomes, and autophagy, which contributes to chondrocyte survival/apoptosis. This study represents the first functional study of Fis1 with its pathological relevance to OA. Our data suggest a new target for controlling cartilage-degenerative diseases, such as OA.

KEY MESSAGE

Fis1 suppression in OA chondrocytes induces accumulation and inhibition of lysosomes. Fis1 suppression alters miRNAs, especially those implicated in lysosomal regulation. Lysosomal destruction results in chondrocyte apoptosis and suppression of autophagy. Fis1 depletion in zebrafish causes lysosome accumulation, mitochondrial dysfunction, and peroxisome reduction. This is the first functional study of Fis1 and its pathological relevance to OA.

The IGF-1R/AKT pathway determines cell fate in response to p53

p53 that is activated in response to DNA-damaging stress can induce apoptosis or either transient or permanent cell cycle arrests. Apoptosis and permanent cell cycle arrest (senescence) are bona-fide tumor suppressor mechanisms through which p53 inhibits cancer cell survival. In contrast, transient cell cycle arrests induced by p53 can increase survival by allowing cells time to repair their DNA before proceeding with cell division. Mechanisms that control the choice of response to p53 (apoptosis vs arrest) are not fully understood. There is abundant crosstalk between p53 and the IGF-1R/AKT/mTORC1 signaling pathway. Recent studies indicate this crosstalk can determine the choice of response to p53. These findings have clear implications for the potential use of IGF-1R pathway inhibitors against p53 wild-type or p53-null or mutant cancers.

Rosuvastatin safety: An experimental study of myotoxic effects and mitochondrial alterations in rats

Myopathy is the most commonly reported adverse effect of statins. All statins are associated with myopathy, though with different rates. Rosuvastatin is a potent statin reported to induce myopathy comparable to earlier statins. However, in clinical practice most patients could tolerate rosuvastatin over other statins. This study aimed to evaluate the myopathic pattern of rosuvastatin in rats using biochemical, functional and histopathological examinations. The possible deleterious effects of rosuvastatin on muscle mitochondria were also examined. The obtained results were compared to myopathy induced by atorvastatin in equimolar dose. Results showed that rosuvastatin induced a rise in CK, a slight increase in myoglobin level together with mild muscle necrosis. Motor activity, assessed by rotarod, showed that rosuvastatin decreased rats' performance. All these manifestations were obviously mild compared to the prominent effects of atorvastatin. Parallel results were obtained in mitochondrial dysfunction parameters. Rosuvastatin only induced a slight increase in LDH and a minor decrease in ATP (∼14%) and pAkt (∼12%). On the other hand, atorvastatin induced an increase in LDH, lactate/pyruvate ratio and a pronounced decline in ATP (∼80%) and pAkt (∼65%). These findings showed that rosuvastatin was associated with mild myotoxic effects in rats, especially when compared to atorvastatin.

CSPGs inhibit axon branching by impairing mitochondria-dependent regulation of actin dynamics and axonal translation

Chondroitin sulfate proteoglycans (CSPGs) inhibit the formation of axon collateral branches. The regulation of the axonal cytoskeleton and mitochondria are important components of the mechanism of branching. Actin-dependent axonal plasticity, reflected in the dynamics of axonal actin patches and filopodia, is greatest along segments of the axon populated by mitochondria. It is reported that CSPGs partially depolarize the membrane potential of axonal mitochondria, which impairs the dynamics of the axonal actin cytoskeleton and decreases the formation and duration of axonal filopodia, the first steps in the mechanism of branching. The effects of CSPGs on actin cytoskeletal dynamics are specific to axon segments populated by mitochondria. In contrast, CSPGs do not affect the microtubule content of axons, or the localization of microtubules into axonal filopodia, a required step in the mechanism of branch formation. It is also reported that CSPGs decrease the mitochondria-dependent axonal translation of cortactin, an actin associated protein involved in branching. Finally, the inhibitory effects of CSPGs on axon branching, actin cytoskeletal dynamics and the axonal translation of cortactin are reversed by culturing neurons with acetyl-l-carnitine, which promotes mitochondrial respiration. Collectively these data indicate that CSPGs impair mitochondrial function in axons, an effect which contributes to the inhibition of axon branching. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 419-437, 2017.

Insulin Postconditioning Reduces Infarct Size in the Porcine Heart in a Dose-Dependent Manner

AIM

Insulin and glucose may have opposite effects when used to reduce ischemia-reperfusion injury. When insulin is administered alone, feeding state determines tolerance and further induces metabolic and hormonal changes. Higher insulin doses are needed for similar activation of cardioprotective Akt signaling in the fed compared to the fasted pig heart. Thus, the aim of the study was to investigate the effects of 2 prespecified insulin doses on infarct size, apoptosis, metabolism, and cardiac function in a clinically relevant, randomized large animal model using conventional percutaneous catheter intervention techniques and including different fasting states.

METHODS AND RESULTS

Twenty-seven female pigs were subjected to 40-minute ischemia and 120-minute reperfusion. Pharmacological postconditioning with intracoronary infusions administered over 3 × 30 seconds was performed at immediate reperfusion. Animals were randomly assigned to 3 groups-preexperimental fasting and intracoronary saline ( controls), preexperimental fasting and 0.1U of insulin ( fasted Ins_0.1U), and preexperimental feeding and 1.0U of insulin ( fed Ins_1.0U). A significant reduction in infarct size was demonstrated in the fed Ins_1.0U group ( P = .047) but not in the fasted Ins_0.1U group ( P = .531) compared to controls (infarct size normalized to area at risk ± standard deviation: controls 70.2% ± 12.9%, fasted Ins_0.1U 65.0% ± 9.4%, and fed Ins_1.0U 54.4% ± 7.3%). Infarct limitation was associated with more uncleaved caspase-3 in the area of risk and the infarcted area, lower circulating free fatty acids, and less increase in heart rate during reperfusion. Fed animals had higher levels of glucose, carnitine, potassium, and normetanephrine and higher heart rate at baseline compared to controls.

CONCLUSION

Insulin postconditioning reduced infarct size in the in vivo pig heart, but the beneficial effects were restricted to the highest dose, which is limited by side effects and can only be given to nonfasted animals. The finding challenges successful general use of insulin in the treatment of reperfusion injury in clinical acute myocardial infarction.

Elucidation of the mechanism of atorvastatin-induced myopathy in a rat model

Myopathy is among the well documented and the most disturbing adverse effects of statins. The underlying mechanism is still unknown. Mitochondrial dysfunction related to coenzyme Q10 decline is one of the proposed theories. The present study aimed to investigate the mechanism of atorvastatin-induced myopathy in rats. In addition, the mechanism of the coenzyme Q10 protection was investigated with special focus of mitochondrial alterations. Sprague-Dawely rats were treated orally either with atorvastatin (100mg/kg) or atorvastatin and coenzyme Q10 (100mg/kg). Myopathy was assessed by measuring serum creatine kinase (CK) and myoglobin levels together with examination of necrosis in type IIB fiber muscles. Mitochondrial dysfunction was evaluated by measuring muscle lactate/pyruvate ratio, ATP level, pAkt as well as mitochondrial ultrastructure examination. Atorvastatin treatment resulted in a rise in both CK (2X) and myoglobin (6X) level with graded degrees of muscle necrosis. Biochemical determinations showed prominent increase in lactate/pyruvate ratio and a decline in both ATP (>80%) and pAkt (>50%) levels. Ultrastructure examination showed mitochondrial swelling with disrupted organelle membrane. Co-treatment with coenzyme Q10 induced reduction in muscle necrosis as well as in CK and myoglobin levels. In addition, coenzyme Q10 improved all mitochondrial dysfunction parameters including mitochondrial swelling and disruption. These results presented a model for atorvastatin-induced myopathy in rats and proved that mitochondrial dysfunction is the main contributor in statin-myopathy pathophysiology.

Estrogen modulation of calretinin and BDNF expression in midbrain dopaminergic neurons of ovariectomised mice

Estrogen attenuates the loss of dopamine neurons from the substantia nigra in animal models of Parkinson's disease (PD) and excitatory amino-acid induced neurotoxicity by interactions with brain-derived neurotrophic factor (BDNF), and calretinin (CR) containing dopaminergic (DA) neurons. To examine this interaction more closely, we treated the ovariectomised (OVX) mice with estrodial for 10days, and compared these mice to those OVX mice injected with the vehicle or control mice. Estrogen treatment in OVX mice had significantly more tyrosine hydroxylase (TH) positive neurons in the substantia nigra pars compacta (SNpc). Dopamine transporter (DAT) mRNA and BDNF mRNA levels in the midbrain were also significantly increased by estrogen treatment (P<0.05). OVX markedly decreased the number of TH/CR double stained cells in the SNpc (P<0.05), a trend which could be reversed by estrogen treatment. However, the number of GFAP positive cells in the substantia nigra did not show significant changes (P >0.05) after vehicle or estrodial treatment. Furthermore, we found that estrogen treatment abrogated the OVX-induced decrease in the phosphorylated AKT (p-AKT), but not p-ERK. We hypothesize that short-term treatment with estrogen confers neuroprotection to DA neurons by increasing CR in the DA neurons and BDNF in the midbrain, which possibly related to activation of the PI3K/Akt signaling pathway.

The anti-hypertensive drug prazosin inhibits glioblastoma growth via the PKCδ-dependent inhibition of the AKT pathway

A variety of drugs targeting monoamine receptors are routinely used in human pharmacology. We assessed the effect of these drugs on the viability of tumor-initiating cells isolated from patients with glioblastoma. Among the drugs targeting monoamine receptors, we identified prazosin, an α1- and α2B-adrenergic receptor antagonist, as the most potent inducer of patient-derived glioblastoma-initiating cell death. Prazosin triggered apoptosis of glioblastoma-initiating cells and of their differentiated progeny, inhibited glioblastoma growth in orthotopic xenografts of patient-derived glioblastoma-initiating cells, and increased survival of glioblastoma-bearing mice. We found that prazosin acted in glioblastoma-initiating cells independently from adrenergic receptors. Its off-target activity occurred via a PKCδ-dependent inhibition of the AKT pathway, which resulted in caspase-3 activation. Blockade of PKCδ activation prevented all molecular changes observed in prazosin-treated glioblastoma-initiating cells, as well as prazosin-induced apoptosis. Based on these data, we conclude that prazosin, an FDA-approved drug for the control of hypertension, inhibits glioblastoma growth through a PKCδ-dependent mechanism. These findings open up promising prospects for the use of prazosin as an adjuvant therapy for glioblastoma patients.