Terlipressin relieves intestinal and renal injuries induced by acute mesenteric ischemia via PI3K/Akt pathway.

Background: To date, the effect of vasopressin on organ damages after acute mesenteric ischemia (MI) remains poorly understood. Aims: To investigate the effect of terlipressin, a selective vasopressin V1 receptor agonist, versus norepinephrine on the intestinal and renal injuries after acute MI, and to explore the underlying mechanism of terlipressin. Methods: Acute MI model was produced by clamping the superior mesenteric artery for 1 hour. Immediately after unclamping, terlipressin or norepinephrine was intravenously administered for 2 hours. Meanwhile, in vitro, RAW264.7 cells were treated with lipopolysaccharide or lipopolysaccharide+terlipressin. In addition, wortmannin was used to determine the role of phosphoinositide 3-kinase (PI3K)/ protein kinase B (Akt) pathway in the potential impacts of terlipressin. Results: MI led to severe hypotension, caused notable intestinal and renal impairments and resulted in high mortality, which were markedly improved by terlipressin or norepinephrine. Terlipressin increased mean arterial pressure, decreased intestinal epithelial cell apoptosis, inhibited the generation of M1 macrophage in intestinal and renal tissues, and hindered the release of inflammatory cytokines after MI. Moreover, in cultured macrophages, terlipressin reduced the mRNA level of specific M1 markers and the release of inflammatory cytokines caused by lipopolysaccharide challenge. Wortmannin decreased the expression of PI3K and Akt induced by terlipressin in cells and in tissues, and abolished the above protective effects conferred by terlipressin. Conclusions: Terlipressin or norepinephrine could effectively improve organ damages and mortality after acute MI. Terlipressin elevates blood pressure and inhibits intestinal epithelial apoptosis and macrophage M1 polarization via the PI3K/Akt pathway.

Application of Cell Impedance as a Screening Tool to Discover Modulators of Intraocular Pressure.

Purpose: To identify new targets and compounds involved in mediating cellular contractility or relaxation in trabecular meshwork (TM) cells and test their efficacy in an ex vivo model measuring outflow facility. Methods: A low-molecular weight compound library composed of 3,957 compounds was screened for cytoskeletal changes using the Acea xCelligence impedance platform in immortalized human NTM5 TM cells. Hits were confirmed by 8-point concentration response and were subsequently evaluated for impedance changes in 2 primary human TM strains, as well as cross-reactivity in bovine primary cells. A recently described bovine whole eye perfusion system was used to evaluate effects of compounds on aqueous outflow facility. Results: The primary screen conducted was robust, with Z' values >0.5. Fifty-two compounds were identified in the primary screen and confirmed to have concentration-dependent effects on impedance in NTM5 cells. Of these, 9 compounds representing distinct drug classes were confirmed to modulate impedance in both human primary TM cells and bovine cells. One of these compounds, wortmannin, an inhibitor of phosphoinositide 3-kinase, increased outflow facility by 11%. Conclusions: A robust phenotypic assay was developed that enabled identification of contractility modulators in immortalized TM cells. The screening hits were translatable to primary TM cells and modulated outflow facility in an ex vivo perfusion assay.

Dexmedetomidine Ameliorates Post-CPB Lung Injury in Rats by Activating the PI3K/Akt Pathway.

Purpose: To investigate the protective effects of dexmedetomidine (Dex) on post cardiopulmonary bypass (CPB) lung injury in rats and to explore the possibility of underlying mechanisms involving phosphatidylinositol 3-kinase (PI3K)/Akt. Materials and Methods: Forty healthy male Sprague-Dawley rats were randomly divided into five groups (n = 8 for each). A left lung ischemia-reperfusion injury model of CPB was established in all five groups. Rats were given saline, dexmedetomidine (Dex), dimethyl sulfoxide (DMSO), wortmannin (Wtm), and Dex plus Wtm during the CPB process, in Group Saline, Dex, DMSO, Wtm, and Dex + Wtm, respectively. Mean arterial pressure, oxygenation index (OI), and respiratory index (RI) were measured at the following three timepoints: before CPB (T1), at the onset of opening of the left hilus pulmonis (T2), and at the end of the CPB process (T3). At T3, hematoxylin and eosin (H&E) staining was conducted to evaluate pathology of lung injury. The rate of lung tissue apoptosis was determined by flow-cytometry. The expression of Akt, p-Akt, caspase-3, and caspase-9 was assessed by Western blot. Results: Dex treatment during CPB protected rat lungs from post-CPB lung injury, manifested by improved lung function, mitigated pathological damage, and reduced lung tissue apoptosis. The expression and phosphorylation of Akt was significantly enhanced by Dex treatment compared to the saline/DMSO-treated group. Wtm, a recognized PI3K inhibitor, abolished the protective effect of Dex. The levels of caspase-3 and caspase-9 were also significantly elevated in the Wtm-treated group. Conclusions: Dex reduces post-CPB lung injury in rats, at least partially, by activating the PI3K/Akt pathway and inhibiting lung tissue apoptosis.

Regulatory role of hippocampal PI3K and mTOR signaling pathway in NMDA-induced infant spasm rats.

Objectives: To explore the role of mTOR signaling pathway in modulating epileptogenesis in an N-methyl-D-aspartic acid (NMDA)-induced infant spasm (IS) rat model. Methods: After inducing IS successfully, the phosphorylation status of PI3K, Akt, mTOR and S6K of brain and hippocampus tissues was assessed using western blot and immunochemistry analysis, respectively. The possible mechanism of mTOR signaling pathway was evaluated by the, inhibitors for mTOR and PI3K, rapamycin and wortmannin, respectively. The inhibitors were injected into the intraperitoneal space of the rats to examine the effects of PI3K and mTOR in IS rat model. Results: The phosphorylated levels of mTOR and PI3K in hippocampus increased significantly (P < 0.05) 7 days after IS induction in rats. After administration of wortmannin, the phosphorylated levels of PI3K and mTOR decreased. However, only the phosphorylated level of mTOR decreased obviously after rapamycin administration. No obvious neurogenesis was found after IS induction. Discussion: Results of the present study suggest that hippocampal PI3K may be another potential target for IS treatment.

Adenovirus type 36 regulates adipose stem cell differentiation and glucolipid metabolism through the PI3K/Akt/FoxO1/PPARγ signaling pathway.

BACKGROUND: This study aims to investigate the molecular mechanism of Adenovirus type 36 (Ad36) in adipocyte differentiation and glucolipid metabolism. METHODS: Rat obesity model was established by Ad36 infection and high-fat diet, respectively. Comparison of the body weight, clinical biochemical indicators, insulin sensitivity and lipid heterotopic deposition between these two models was performed. Ad36-induced adipocyte in vitro model was also established. The binding rate of FoxO1, PPARγ and its target gene promoter was detected using ChIP. The mRNA and protein expression levels of PPARγ and downstream target genes were detected by RT-PCR and Western blot, respectively. Oil red O staining was used to measure differentiation into adipocyte. Wortmannin (WM), inhibitor of PI3K, was used to act on Ad36-induced hADSCs. RESULTS: Ad36-induced obese rats did not exhibit disorders in blood glucose and blood TG, insulin resistance and lipid ectopic deposition. The expression of Adipoq, Lpin1 and Glut4 in the adipose tissue increased. Oil red O staining showed that Ad36 induced the differentiation of hAMSCs into human adipocytes in vitro. During this process, the binding rate of FoxO1 and PPARγ promoter regions was weakened. However, the binding rate of the transcription factor PPARγ to its target genes Acc, Adipoq, Lpin1 and Glut4 was enhanced, and thus increased the protein expression of P-FoxO1, PPARγ2, ACC, LPIN1, GLUT4 and ADIPOQ. The PI3K inhibitor Wortmannin reduced the expression of P-Akt, P-FoxO1 and PPARγ2, thereby inhibiting adipogenesis of hADSC. CONCLUSION: Ad36 may promote fatty acid and triglyceride synthesis, and improve insulin sensitivity by affecting the PI3K/Akt/FoxO1/PPARγ signaling pathway.

Melatonin Attenuates Acute Pancreatitis-Induced Liver Damage Through Akt-Dependent PPAR-γ Pathway.

BACKGROUND: Despite melatonin treatment diminishes inflammatory mediator production and improves organ injury after acute pancreatitis (AP), the mechanisms remain unknown. This study explores whether melatonin improves liver damage after AP through protein kinase B (Akt)-dependent peroxisome proliferator activated receptor (PPAR)-γ pathway. METHODS: Male Sprague-Dawley rats were subjected to cerulein-induced AP. Animals were treated with vehicle, melatonin, and melatonin plus phosphoinositide 3-kinase (PI3K)/Akt inhibitor wortmannin 1 h following the onset of AP. Various indicators and targeted proteins were checked at 8 h in the sham and AP groups. RESULTS: At 8 h after AP, serum alanine aminotransferase/aspartate aminotransferase levels, histopathology score of hepatic injury, liver myeloperoxidase activity, and proinflammatory cytokine production were significantly increased and liver tissue adenosine triphosphate concentration was lower compared with shams. AP resulted in a marked decrease in liver Akt phosphorylation and PPAR-γ expression in comparison with the shams (relative density, 0.442 ± 0.037 versus. 1.098 ± 0.069 and 0.390 ± 0.041 versus ± 1.080 0.063, respectively). Melatonin normalized AP-induced reduction in liver tissue Akt activation (1.098 ± 0.054) and PPAR-γ expression (1.145 ± 0.083) as well as attenuated the increase in liver injury markers and proinflammatory mediator levels, which was abolished by coadministration of wortmannin. CONCLUSIONS: Collectively, our findings suggest that melatonin improves AP-induced liver damage in rats, at least in part, via Akt-dependent PPAR-γ pathway.

Chinese herbal decoction of Wenshen Yangxue formula improved fertility and pregnancy rate in mice through PI3K/Akt signaling.

OBJECTIVE: Traditional Chinese medicine (TCM) is an effective management to infertility. The association between TCM-mediated fertility and inhibition of phosphatidylinositol-3-kinase (PI3K) would be investigated. METHODS: Institute of Cancer Research mice were treated with three herbal decoctions, named Wenshen Yangxue formula, Wenshen formula, and Yangxue formula, plus with human gonadotropins. PI3K inhibitor wortmannin was administrated to half of mice. Some index such as body weight, fertility ability would be investigated. The expression of P13K/Akt signaling was detected by using Western blot analysis. RESULTS: No difference was observed in body weight among groups. Mice receiving the administration of human gonadotropins and herbal decoctions showed increased follicle numbers, percentage of fertilization, and promoted embryonic development. The treatment of Wenshen Yangxue formula decoction showed the highest efficiency, significant higher than Wenshen and Yangxue formulas. And increased the expression of p-PI3K and p-Akt proteins. CONCLUSION: These results suggested the herbal decoctions promoted the fertilization of mice, which was related to the charge of PI3K/Akt activation.

Invasive Colon Cancer Cells Induce Transdifferentiation of Endothelium to Cancer-Associated Fibroblasts through Microtubules Enriched in Tubulin-ß3.

Colon cancer, the second leading cause of cancer-related deaths in the world, is usually diagnosed in invasive stages. The interactions between cancer cells and cells located in their niche remain the crucial mechanism inducing tumor metastasis. The most important among those cells are cancer-associated fibroblasts (CAFs), the heterogeneous group of myofibroblasts transdifferentiated from numerous cells of different origin, including endothelium. The endothelial-to-mesenchymal transition (EndMT) is associated with modulation of cellular morphology, polarization and migration ability as a result of microtubule cytoskeleton reorganization. Here we reveal, for the first time, that invasive colon cancer cells regulate EndMT of endothelium via tubulin-ß3 upregulation and its phosphorylation. Thus, we concluded that therapies based on inhibition of tubulin-ß3 expression or phosphorylation, or blocking tubulin-ß3's recruitment to the microtubules, together with anti-inflammatory chemotherapeutics, are promising means to treat advanced stages of colon cancer.

Nanoparticle co-delivery of wortmannin and cisplatin synergistically enhances chemoradiotherapy and reverses platinum resistance in ovarian cancer models.

Most ovarian cancer patients respond well to initial platinum-based chemotherapy. However, within a year, many patients experience disease recurrence with a platinum resistant phenotype that responds poorly to second line chemotherapies. As a result, new strategies to address platinum resistant ovarian cancer (PROC) are needed. Herein, we report that NP co-delivery of cisplatin (CP) and wortmannin (Wtmn), a DNA repair inhibitor, synergistically enhances chemoradiotherapy (CRT) and reverses CP resistance in PROC. We encapsulated this regimen in FDA approved poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG) NPs to reduce systemic side effects, enhance cellular CP uptake, improve Wtmn stability, and increase therapeutic efficacy. Treatment of platinum-sensitive ovarian cancer (PSOC) and PROC murine models with these dual-drug loaded NPs (DNPs) significantly reduced tumor burden versus treatment with combinations of free drugs or single-drug loaded NPs (SNPs). These results support further investigation of this NP-based, synergistic drug regimen as a means to combat PROC in the clinic.

Colorectal cancer lung metastasis treatment with polymer-drug nanoparticles.

Colorectal cancer (CRC) is the second leading cause of cancer deaths in the United States; the predominant cause for mortality is metastasis to distant organs (e.g., lung). A major problem limiting the success of chemotherapy in metastatic CRC is the inability to target tumor tissues selectively and avoid severe side effects to normal tissues and organs. Here, we demonstrate polymeric nanoparticles (PNPs) entrapping chemotherapeutic agents provide a new therapeutic option for treating CRC that has metastasized to the lung. PNPs assembled from FDA approved biocompatible block copolymer accumulated predominantly in lung tissue. PNPs showed negligible accumulation in liver, spleen and kidneys, which was confirmed by fluorescent nanoparticle imaging and analysis of PI3K inhibition in the organs. PNPs entrapping PI3K inhibitors (i.e., wortmannin and PX866) suppressed CRC lung metastasis growth, and SN-38-loaded PNPs completely eliminated CRC lung metastasis. Our results demonstrate that polymer-drug nanoparticles offer a new approach to reduce toxicity of cancer therapy and has the potential to improve outcomes for patients with lung metastasis.

Inhibition of Phosphatidylinositol 3-kinease suppresses formation and progression of experimental abdominal aortic aneurysms.

Accumulating evidence suggests an important role of Phosphatidylinositol 3-kinease (PI3K) pathway in inflammatory cells infiltration. Given the essential role of inflammatory cells infiltration during the formation and progression of abdominal aortic aneurysm (AAA), to investigate the possibility of preventing AAA formation and progression via targeting PI3K is anticipated. Here, experimental AAAs was created in rats by transient intraluminal porcine pancreatic elastase (PPE) infusion into the infrarenal aorta firstly. AAAs rats were administrated with vehicle or Wortmannin during the period of day 0 to day 28 after PPE infusion. The aortic diameter of rats treated with Wortmannin was significantly smaller than those treated with vehicle. Meanwhile, Elastin destruction score and SMC destruction score were significantly decreased in rats treated with Wortmannin. Furthermore, histological analysis revealed infiltration of inflammatory cells were significantly reduced in rats treated with Wortmannin. Finally, the mRNA expression of PI3K and protein expression of pAKT in human abdominal aneurismal aorta tissues was elevated as compare to normal aorta. Our study revealed that PI3K inhibitor suppresses experimental AAAs formation and progression, through mechanisms likely related to impairing inflammation cells infiltration and median elastin degradation. These findings indicated that PI3K inhibitor may hold substantial translation value for AAA diseases.

Exendin-4 reduces food intake via the PI3K/AKT signaling pathway in the hypothalamus.

Exendin-4 (EX-4), a glucagon-like peptide-1 (GLP-1) receptor agonist, has been shown to reduce food intake and to increase proopiomelanocortin (POMC) gene expression in the hypothalamus. In this study, we examined the potential neural mechanisms by which these effects occur. Male Sprague Dawley rats were implanted with a cannula in the third ventricle of the brain through which an inhibitor of phosphatidylinositol-3 kinase (PI3K) (wortmannin) was administered, and EX-4 or vehicle was administered via intraperitoneal (IP) injection. The activity of PI3K/protein kinase B (AKT) and insulin receptor substrate-1 (IRS-1) in the hypothalamic arcuate was determined. We found that EX-4 treatment significantly decreased food intake and body weight. However, there were almost no changes in food intake and body weight when wortmannin injection (into the third ventricle) occurred prior to EX-4 IP injection. EX-4 not only increased the activity of PI3K/AKT, but it also increased IRS-1 activity. These results show that EX-4 likely suppresses food intake due to its ability to enhance insulin signaling.

Reversal of cisplatin resistance by inhibiting PI3K/Akt signal pathway in human lung cancer cells.

Cisplatin is regularly used in the treatment of lung cancer. However, its efficacy is limited because of drug resistance. In this study, we found that Akt expression and activity was increased in lung cancer cells with acquired cisplatin resistance (A549/DDP cells and H460/DDP cells) when compared to their parental cells. Inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt kinase activity by its natural inhibitor, Wortmannin, could sensitize DDP-resistant cells to DDP and reverse DDP resistance. Combination treatment of Wortmannin with cisplatin is capable of increasing the mortality rate of both A549/DDP cells and H460/DDP cells. The present study also demonstrated that hyperactivation of PI3K/Aktpathway is closely associated with cisplatin resistance by regulating the Bax-mitochondria-mediated apoptosis pathway in human lung cancer. Inhibition of PI3K/Aktactivity in A549/DDP cells and H460/DDP cells could reverse cisplatin resistance by enhancing the effect of cisplatin on Bax oligomerization and release of Cytochrome C, allowing activation of the caspase-mediated apoptosis pathway. In conclusion, cisplatin resistance of lung cancer can be reversed via the inhibition of the PI3K/Akt signaling pathway. Therefore, both PI3K and Akt may be potential targets for overcoming cisplatin resistance in lung cancer.