PI3K Inhibitor Group Research Articles

Nesfatin-1 regulates the phenotype transition of cavernous smooth muscle cells by activating PI3K/AKT/mTOR signaling pathway to improve diabetic erectile dysfunction.

This study aims to explore the impact of Nesfatin-1 on type 2 diabetic erectile dysfunction (T2DMED) and its underlying mechanism in regulating the phenotypic switching of corpus cavernosum smooth muscle cells (CCSMCs). Twenty-four 4-week-old male C57 wild-type mice were randomly assigned to the control group, model group, and Nesfatin-1 treatment group. Monitoring included body weight, blood glucose levels, and penile cavernous pressure (ICP). Histochemistry and Western blot analyses were conducted to assess the expressions of α-SMA, OPN, and factors related to the PI3K/AKT/mTOR signaling pathway. CCSMCs were categorized into the control group, high glucose and high oleic acid group (GO group), Nesfatin-1 treatment group (GO+N group), sildenafil positive control group (GO+S group), and PI3K inhibitor group (GO+N+E group). Changes in phenotypic markers, cell morphology, and the PI3K/AKT/mTOR signaling pathway were observed in each group. (1) Nesfatin-1 significantly ameliorated the body size, body weight, blood glucose, glucose tolerance, and insulin resistance in T2DMED mice. (2) Following Nesfatin-1 treatment, the ICP/MSBP ratio and the peak of the ICP curve demonstrated a significant increase. (3) Nesfatin-1 significantly enhanced smooth muscle and reduced collagen fibers in the corpus cavernosum. (4) Nesfatin-1 notably increased α-SMA expression and decreased OPN expression in CCSMCs. (5) Nesfatin-1 elevated PI3K, p-AKT/AKT, and p-mTOR/mTOR levels in penile cavernous tissue. Nesfatin-1 not only effectively improves body weight and blood glucose levels in diabetic mice but also enhances erectile function and regulates the phenotypic switching of corpus cavernosum smooth muscle. The potential mechanism involves Nesfatin-1 activating the PI3K/AKT/mTOR signaling pathway to induce the conversion of CCSMCs to a contractile phenotype.

Nesfatin-1 regulates the phenotype transition of cavernous smooth muscle cells by activating PI3K/AKT/mTOR signaling pathway to improve diabetic erectile dysfunction

ObjectiveThis study aims to explore the impact of Nesfatin-1 on type 2 diabetic erectile dysfunction (T2DMED) and its underlying mechanism in regulating the phenotypic switching of corpus cavernosum smooth muscle cells (CCSMCs). MethodsTwenty-four 4-week-old male C57 wild-type mice were randomly assigned to the control group, model group, and Nesfatin-1 treatment group. Monitoring included body weight, blood glucose levels, and penile cavernous pressure (ICP). Histochemistry and Western blot analyses were conducted to assess the expressions of α-SMA, OPN, and factors related to the PI3K/AKT/mTOR signaling pathway. CCSMCs were categorized into the control group, high glucose and high oleic acid group (GO group), Nesfatin-1 treatment group (GO + N group), sildenafil positive control group (GO + S group), and PI3K inhibitor group (GO + N + E group). Changes in phenotypic markers, cell morphology, and the PI3K/AKT/mTOR signaling pathway were observed in each group. Results(1) Nesfatin-1 significantly ameliorated the body size, body weight, blood glucose, glucose tolerance, and insulin resistance in T2DMED mice. (2) Following Nesfatin-1 treatment, the ICP/MSBP ratio and the peak of the ICP curve demonstrated a significant increase. (3) Nesfatin-1 significantly enhanced smooth muscle and reduced collagen fibers in the corpus cavernosum. (4) Nesfatin-1 notably increased α-SMA expression and decreased OPN expression in CCSMCs. (5) Nesfatin-1 elevated PI3K, p-AKT/AKT, and p-mTOR/mTOR levels in penile cavernous tissue. ConclusionsNesfatin-1 not only effectively improves body weight and blood glucose levels in diabetic mice but also enhances erectile function and regulates the phenotypic switching of corpus cavernosum smooth muscle. The potential mechanism involves Nesfatin-1 activating the PI3K/AKT/mTOR signaling pathway to induce the conversion of CCSMCs to a contractile phenotype.

Protective effects and mechanisms of Xingnaojing Injection on early global brain ischemic-induced deep coma in rats

To study the protective effect of Xingnaojing Injection on early global brain ischemia-induced deep coma in rats. Methods: The deep coma model was induced by global brain ischemia by using four-vessel occlusion method in male SD rats. According to the body weight, the rats were randomly divided into 8 groups: a model control group, three different dose of Xingnaojing Injection (1.8, 3.6 and 5.4 mL.kg-1) groups, a Xingnaojing Injection (3.6 mL.kg-1) plus PI3K inhibitor group, a naloxone injection (0.04 mL.kg-1) group and a naloxone injection (0.04 mL.kg-1) plus Xingnaojing Injection (3.6 mL.kg-1) group (n=8 per group). In addition, eight animals served as the sham group were performed same operation with the model group excepting no blockage of the blood vessels. After the operation, three different doses of Xingnaojing Injection and/or naloxone injection were given intravenously once a day for three days. Ten μL PI3K inhibitor (LY294002, 10 mmol/L) was injected via anterior cerebral ventricle at once after global brain ischemia. The awakening time after the first drug treatment, the grasping power and the autonomous activity within 10 min after the last drug treatment were recorded. The levels of both dopamine (DA) and glutamate (Glu) in cerebrospinal fluid were detected by ELISA. The pathological changes were observed in brain tissue slices with HE staining and the protein levels of Akt/p-Akt and cAMP-response element binding protein (CREB)/p-CREB in hippocampus were detected by Western blotting. Results: Comparing with the model group, single administration of Xingnaojing Injection could significantly shorten the waking time (P<0.05) and continuous administration of Xingnaojing Injection for 3 d could increase grasping power, distance, frequency and duration of autonomous activities (P<0.05 or P<0.01) in the deep coma rat. Also, Xingnaojing Injection could inhibit these increases in neurotransmitters DA and Glu contents (P<0.05 or P<0.01), and improve pathological changes of hippocampal tissue. Xingnaojing Injection significantly induced protein phosphorylation of both Akt and CREB (P<0.05 or P<0.01); this effect was inhibited by PI3K inhibitor (P<0.05 or P<0.01). Moreover, the protective effects of naloxone on awakening time, grasping power, the autonomous activity and hippocampus damage in global brain ischemia-induced deep coma could be enhanced by joint use of Xingnaojing Injection (P<0.05 or P<0.01). Conclusion: Xingnaojing Injection could significantly improve deep coma induced by global brain ischemia in rat, which is related to inducing PI3K/Akt-dependent protein phosphorylation of CREB, and reducing hippocampal damage. The protective effect of Xingnaojing Injection is synergistically enhanced by naloxone.

Effect and mechanisms of sacral nerve stimulation on visceral hypersensitivity mediated by nerve growth factor.

To investigate the efficacy of sacral nerve stimulation (SNS) on nerve growth factor (NGF) mediated visceral sensitivity in normal rat and visceral hypersensitivity model rats. 120 male newborn rats were randomly divided into 6 groups: group A was normal model group; group B ~ F were all sensitized with acetic acid enema and grouped again. Group c2 was given NGF antagonist, d2 group was given NGF agonist, e2 group was given PI3K inhibitor, and f2 group was given PLC‐γ inhibitor. After treatment, the expression of NGF, TrKA, PI3K, AKT, PLC‐γ, NF‐κB, TRPV1, pTRPV1 and intracellular Ca2+ content were detected. The expression of protein TRPV1 and pTRPV1 was increased, and Ca2+ was increased in the visceral hypersensitive group. NGF, TrKA in NGF antagonist group, PI3K, AKT, NF‐κB in PI3K inhibitor group, PLC‐γ in PLC‐γ inhibitor group were all almost not expressed. The relative expression of NGF, TrKA, PI3K, AKT, PLC‐γ and NF‐κB in NGF antagonist group was lower than that in visceral hypersensitivity group and NGF activator group (P < .01). The relative expression of NGF, TrKA, PI3K and AKT mRNA in NGF antagonist group was lower than that in the normal model group (P < .01). There was no significant difference in the relative expression of PLC‐γ and NF‐κB mRNA (P > .05). The expression level of MAPK, ERK1 and ERK2 in visceral hypersensitivity group was higher than that in PI3K inhibitor group and PLC‐γ inhibitor group. The normal group Ca2+ curve was flat, and the NGF agonist group had the highest Ca2+ curve peak. Calcium concentration in visceral hypersensitivity group was higher than that in PI3K inhibitor group and that in PLC‐γ inhibitor group was higher than that in NGF antagonist group. The binding of TrkA receptor to NGF activates the MAPK/ERK pathway, the PI3K/Akt pathway and the PLC‐γ pathway, causing changes in the fluidity of intracellular and extracellular Ca2+, resulting in increased sensitivity of visceral tissues and organs.

The bone marrow mononuclear cells reduce the oxidative stress of cerebral infarction through PI3K/AKT/NRF2 signaling pathway.

To evaluate the mechanism of bone marrow mononuclear cells (BMMNCs) in reducing the oxidative stress after cerebral infarction through PI3K/AKT/NRF2 signaling pathway. 96 healthy SD rats, which were 6-8-week old, weighting about 250-280 g, were selected for the study. The middle cerebral artery occlusion model (MCAO) was established in SD rats using the suture method. The rats were randomly divided into sham operation group, model group, BMMNCs group and PI3K inhibitor group. 24 rats in each group were selected. 200 μl phosphate-buffered saline (PBS) solution was injected into the caudal vein of the rats in the model group, 200 μl PBS solution containing 5×106 BMMNCs that obtained by gradient centrifugation was injected into the rats in the BMMNCs group, meanwhile, in the PI3K inhibitor group, LY294002 (10 mmol/L/kg) was injected into the lateral ventricle of the brain. After the 3d, 7d and 14d, the modified neurological severity scores (mNSS) were used to evaluate the neurological function. The volume of cerebral infarction was assessed by TTC staining, the VEGF, BDNF, TNF-α, IL-1β, malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels were detected by ELISA. The mNSS and the volume of cerebral infarction of the model group were significantly higher than those of the sham operation group (p<0.05), while the mNSS and the volume of cerebral infarction of the BMMNCs group were lower than those of the model group, higher than those of the sham operation group (p<0.05). The VEGF, BDNF, TNF-α, IL-1β, MDA, SOD and GSH-Px levels of the model group were significantly higher than those of the sham operation group (p<0.05). BMMNCs can reduce the oxidative stress, apoptosis, and inflammatory reaction through PI3K/AKT/NRF2 signaling pathway, thus promoting the secretion of nerve and vascular cytokines, improving the neurological function and reducing the infarct scope.

Ginsenoside-Rb3 inhibits endothelial-mesenchymal transition of cardiac microvascular endothelial cells.

We investigated the effect of Ginsenoside-Rb3 (Rb3) on the endothelial-to-mesenchymal transition (EMT) of cardiac microvascular endothelial cells (CMVECs) following coxsackievirus B3 (CVB3) infection. CMVECs were infected with 100 TCID50 CVB3 (CVB3 group) or treated with Rb3 (Rb3 group); stably cultured CMVECs were used as control. Cells treated with the Pyk2 inhibitor TAE226 and PI3K inhibitor LY294002 were used for additional experiments. Cell viability was assessed with the Cell Counting Kit-8 (CCK8). Expression of CD31 and α‑smooth muscle actin (α-SMA) was evaluated by immunofluorescence (IF) and Western blotting (WB). Expression of Pyk2, PI3K, and AKT was assessed by real-time polymerase chain reaction (RT-PCR) and WB. Cell morphology, including cell pyknosis, and viability were significantly impaired by CVB3 infection (p< 0.05). However, the morphology of the Rb3 group was unaffected. The CCK8 assay showed that viability in the Rb3 group was increased compared with the CVB3 group (p< 0.05). Expression of CD31 decreased and α‑SMA increased in the CVB3 group compared with the control group (p< 0.05), but CD31 increased while α‑SMA decreased in the Rb3 group compared with the CVB3 group (p< 0.05). IF staining showed the same trends. The levels of Pyk2, PI3K, AKT, and CD31 were up-regulated in the Rb3 group compared with the CVB3 group, whereas α‑SMA decreased (p< 0.05). In the Pyk2-inhibitor group, PI3K, AKT, and CD31 expression was down-regulated while α‑SMA expression increased in comparison with the Rb3 group (p< 0.05). In the PI3K-inhibitor group, the levels of AKT and CD31 decreased while α‑SMA increased (p< 0.05), although the level of Pyk2 expression showed no obvious change in comparison with the Rb3 group. Rb3 inhibited EMT in CMVECs following CVB3 infection via the Pyk2-PI3K-AKT signaling pathway.

The effect of AdipoRon on insulin sensitivity of mouse skeletal muscle cells and its mechanism

To observe the effect of AdipoRon, an adiponin receptor agonist, on insulin sensitivity in mouse myoblast cell line (C2C12) and to explore its mechanism. C2C12 was induced to differentiate into myoblasts by using horse serum. Then the cells were divided into 6 groups (9 double wells):blank control group, high dose AdipoRon group, low dose AdipoRon group, insulin group and the low dose AdipoRon with PI3K inhibitor (phosphatidylinositol 3 kinase) group and the insulin with PI3K inhibitor group. After cultured for 12 h, the supernatant was collected and glucose consumption was measured. Cell proliferation was tested by using CCK8. In the 6-well plate, C2C12 was induced to differentiate into myoblasts. The drug was incubated for 12 h and the mRNA level of GLUT4 was detected by RT-PCR. Compared with the blank control group, the levels of glucose consumption in high dose AdipoRon group, low dose AdipoRon group and insulin group was increased significantly (P<0.05). After adding PI3K inhibitor, the levels of glucose consumption in the above mentioned three groups were not different from that in blank control group. high dose AdipoRon group, low dose AdipoRon group and insulin group had proliferation, but only the insulin group was statistically significant (P<0.05). Compared with the control group, the levels of GLUT4 mRNA in AdipoRon high dose group, low dose AdipoRon group and insulin group were all higher than those in control group (P<0.05). After adding PI3K inhibitor, GLUT4 mRNA level was not statistically significant compared with blank control group. AdipoRon can increase the consumption of glucose without affecting cell proliferation, which may play a role in improving insulin sensitivity, but the specific mechanism remains to be further studied.

Growth inhibition of combined pathway inhibitors on KRAS mutated non-small cell lung cancer cell line

To investigate the effect of the selective PI3K inhibitor and MEK inhibitor on KRAS and PTEN co-mutated non-small cell lung cancer cell line NCI-H157 and the relevant mechanisms. NCI-H157 was cultured routinely and treated with different concentrations of the two inhibitors. Cell proliferation was detected by MTT cell cycle assay. Based on the MTT results the cells were divided into four groups: the control group, PI3K inhibitor group (GDC-0941, 0.5 and 5.0 µmol/L), combination group I (0.5 µmol/L AZD6244 + 0.5 µmol/L GDC-0941) and combination group II (5.0 µmol/L AZD6244 + 5.0 µmol/L GDC-0941). Colony formation assay was performed to detect colony formation efficiency. The cell cycle and apoptosis were analyzed by flow cytometry. The expression of protein related to apoptosis was tested with Western blot. Cell growth was inhibited by the two inhibitors. Combination groups led to stronger cell proliferation inhibition: combination group Ishowed synergistic effect of their actions and combination group II showed an additive effect; in both groups, there were decreased colony number [(77.2 ± 1.54)/well vs (61.50 ± 2.12)/well, P < 0.01] and [(51.00 ± 4.00)/ well vs (22.50 ± 3.53)/well, P < 0.01]; and enhanced apoptotic ratios [(18.30 ± 0.82)% vs (21.32 ± 0.56)%, P < 0.01] and [(27.14 ± 1.58)% vs (42.45 ± 4.42)%, P < 0.01]. In addition, compared to the PI3K inhibitor alone group, the NCI-H157 cells in the combination groups showed increased G0/G1 phase and decreased S phase (P < 0.01). Western blotting showed that the combination groups demonstrated significantly decreased expression of cyclin D1 and cyclin B1, increased p21 and cleaved PARP and decreased bcl-2/bax ratio, compared to the PI3K inhibitor only group. The combined inhibition of PI3K (AZD6244) and MEK (GDC-0941) has synergistic effects on the proliferation of NCI-H157 cells, but such effects appear to be in a dose-dependent manner.

Effects and mechanisms of ghrelin on cardiac microvascular endothelial cells in rats

Ghrelin is thought to directly exert a protective effect on the cardiovascular system, specifically by promoting vascular endothelial cell function. Our study demonstrates the ability of ghrelin to promote rat CMEC (cardiac microvascular endothelial cell) proliferation, migration and NO (nitric oxide) secretion. CMECs were isolated from left ventricle of adult male Sprague-Dawley rat by enzyme digestion and maintained in endothelial cell medium. Dil-ac-LDL (1,1'-dioctadecyl-3,3,3',3'- tetramethylindocarbocyanine-labelled acetylated low-density lipoprotein) intake assays were used to identify CMECs. Cells were split into five groups and treated with varying concentrations of ghrelin as follows: one control non-treated group; three ghrelin dosage groups (1×10-9, 1×10-8, 1×10-7 mol/l) and one ghrelin+PI3K inhibitor group (1×10-7 mol/l ghrelin+20 μmol/l LY294002). After 24 h treatment, cell proliferation capability was measured by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay and Western blot for PCNA (proliferating cell nuclear antigen) protein expression. Migration of CMECs was detected by transwell assays, and NO secretion of CMECs was measured via nitrate reduction. Protein expression of AKT and phosphorylated AKT in CMECs was measured by Western blot after exposure to various concentrations of ghrelin and the PI3K inhibitor LY294002. Our results indicate that ghrelin significantly enhanced cell growth at concentrations of 10-8 mol/l (0.271±0.041 compared with 0.199±0.021, P = 0.03) and 10-7 mol/l (0.296±0.039 compared with 0.199±0.021, P<0.01). However, addition of the PI3K/AKT inhibitor LY294002 inhibited the ghrelin-mediated enhancement in cell proliferation (0.227±0.042 compared with 0.199±0.021, P = 0.15). At a concentration between 10-8 and 10-7 mol/l, ghrelin caused a significant increase in the number of migrated cells compared with the control group (126±9 compared with 98±7, P = 0.02; 142±6 compared with 98±7, P<0.01), whereas no such change could be observed in the presence of 20 μmol/l of the PI3K/Akt inhibitor LY294002 (103±7 compared with 98±7, P = 0.32). Ghrelin treatment significantly enhanced NO production in a dose-dependent fashion compared with the untreated control group [(39.93±2.12) μmol/l compared with (30.27±2.71) μmol/l, P = 0.02; (56.80±1.98) μmol/l compared with (30.27±2.71) μmol/l, P<0.01]. However, pretreatment with 20 μmol/l LY294002 inhibited the ghrelin-stimulated increase in NO secretion [(28.97±1.64) μmol/l compared with (30.27±2.71) μmol/l, P = 0.37]. In summary, we have found that ghrelin treatment promotes the proliferation, migration and NO secretion of CMECs through activation of PI3K/AKT signalling pathway.

Correlation between growth hormone/insulin-like growth factor-1 resistance and insulin resistance in non catch-up growth rats born small for gestational age

To investigate the post-receptor signaling mechanism responsible for insulin resistance-induced growth hormone (GH) resistance in non-catch-up (NCU) growth rats born small for gestational age (SGA). Twenty pregnant female SD rats were fed with restricted food (40% of normal intake, 9 g/d) throughout the pregnancy so as to develop NCU-SGA rats. The rats with their length and body weight < or = -2SD were out into the NCU-SGA group, and those with their length and body weight > -2SD were out into the catch-up (CU) growth group. Rats born to normally-fed pregnant rats were set as normal control (control Group, C Group, n = 17). The body weight and length were measured every 2 weeks. At the age of 4 weeks, 24 h urine was collected to measure the urine GH (U-GH). Then blood samples were collected to measure the serum insulin-like growth factor-1 (IGF-1), fasting insulin (FINS), and glucose levels, and the liver was taken out to detect the expression of STAT5 signal. Twelve 3-week NCU-SGA rats were divided into 2 equal groups: P13K blocking group, undergoing intraperitoneal injection of LY294002, blocker of P13K twice every 3 days, and solvent control group, undergoing intraperitoneal injection of DMSO. At the age of 4 weeks, blood samples were collected and then the liver was taken out to detect the IGF-1 mRNA and STAT5 signal. (1) The body weight and length at birth of the NCU-SGA group were (4.4 +/- 0.5) g and (4.5 +/- 0.2) cm, both significantly lower than those of Group C [(6.8 +/- 0.6) g and (5.3 +/- 0.2) cm respectively], and the body weight and length at 4 weeks of age of the NCU-SGA group were (63 +/- 12) g and (13.2 +/- 1.0) cm respectively, both significantly lower than those of the C group [(88 +/- 12) g and (15.3 +/- 0.5) cm respectively, all P < 0.01]. The serum IGF-1 level, IGF-1 mRNA expression, and total and phosphate STAT5 level in liver of the NCU-SGA group were (248 +/- 58) ng/ml, (6.1 +/- 0.3) copies, and (61 +/- 22)% respectively, all significantly lower than those of the C group [(383 +/- 62) ng/ml, (6.6 +/- 0.4) copies, and (91 +/- 29)%, all P < 0.01]. There was no statistic difference in 24 h U-GH between the NCU-SGA and C groups (P > 0.05). The FINS and glucose level of the NCU-SGA group were (24.7 +/- 9.6) mU/ml and (5.4 +/- 0.3) mmol/L respectively, both significantly higher than those of the C group [(9.8 +/- 2.8) mU/ml and (4.5 +/- 1.7) mmol/L respectively, both P < 0.05]. The level of 24 h U-GH was positively correlated with FINS (r = 0.680, P = 0.000). No correlation was found between IGF-1 and fasting insulin level. (2) After the PI3K pathway was chronically blocked, the NCU-SGA rats lost weight and developed a more severe insulin resistance, decreased serum IGF-1 level and the IGF-1 mRNA expression level of the PI3K inhibitor group were (218 +/- 60) ng/ml and (6.1 +/- 0.3) copies respectively, both significantly lower than those of the solvent control group [(286 +/- 45) ng/ml and (6.3 +/- 0.3) copies, both P < 0.05]. No statistically significant difference in total and phosphate STAT5 levels in liver between the P13K blocker and solvent groups. GH resistance is closely associated with insulin resistance in the NCU-SGA rats. GH resistance-induced failure of catch-up growth is related to the impairment of JAK2-STAT5 pathway. Insulin resistance exacerbates growth axis resistance and growth retardation in NCU-SGA rats via a non-STAT5 dependent pathway.