PDK1 Activity Regulates Proliferation, Invasion and Growth of Hemangiomas.

BACKGROUND: Hemangiomas are common vascular endothelial cell tumors. Abnormally activated PI3K/Akt signaling pathway is one of the most important biological characteristics of Hemangioma. 3-phosphoinositide-dependent kinase 1(PDK1), an upstream protein of Akt, regulates the activity of Akt and its downstream kinases. The objective of this study is to explore the effect of PDK1 on malignant vascular tumors and their cell signaling mechanism in mice. METHODS: Mouse Hemangioendothelioma Endothelial Cells (EOMA cells) and Nu/Nu mice were used. The silencing of PDK1 was mediated by lentiviral shRNA. Western blotting, WST-1 proliferation assay, Matrigel invasion assay, and Xenograft vascular tumor model were utilized to examine the effects and mechanism of PDK1 growth, proliferation, and invasion of an Hemangioma. RESULTS: PDK1 deficiency significantly reduced the proliferation and invasion of EOMA cells in vitro, and depressed the growth of vascular tumor in vivo by decreasing the activity of Akt signaling pathway. CONCLUSION: We hypothesize that PDK1 plays a significant role in the progression and growth of vascular tumors and targeting PDK1 may thus be considered in their treatment.

Low concentration of rapamycin inhibits hemangioma endothelial cell proliferation, migration, and vascular tumor formation in mice.

BACKGROUND: Vascular endothelial cell excessive proliferation is the main biological behavior of hemangioma. Rapamycin regulates the growth of endothelial cells by inhibiting mammalian target of rapamycin (mTOR). Thus hemangioma accompanied by excessive mTOR activation should be sensitive to rapamycin. We aimed to illustrate the effect of low-concentration rapamycin on hemangioma and provide a safe and effective drug therapy. METHODS: Mouse hemangioendothelioma endothelial cells and Nu/Nu mice were used. Rapamycin was applied in a concentration from 1 nM to 20 nM. WST-1 cell proliferation and transwell migration assays were used to analyze vascular tumor proliferation and migration in vitro. Xenograft mouse models were used to test vascular tumor growth in vivo. RESULTS: Low-concentration rapamycin (1 nM) inhibited hemangioendothelioma endothelial cell proliferation and migration in vitro and vascular tumor growth in vivo. The mechanism was decreased activation of the protein kinase B/mTOR/S6 ribosomal protein (S6) signaling pathway. CONCLUSIONS: Rapamycin used in vitro was analogous to low serum concentration rapamycin (7-16 nM) and also significantly inhibited the growth of hemangioma. These results demonstrate a low-toxic drug therapy for hemangioma and encourage continued development of rapamycin and its analogs for use in vascular tumor therapy.

Sirtuin 1 regulates matrix metalloproteinase-13 expression induced by Porphyromonas endodontalis lipopolysaccharide via targeting nuclear factor-κB in osteoblasts.

Porphyromonas endodontalis lipopolysaccharide (P.e LPS) is an important initiating factor for periapical inflammation and bone destruction. Matrix metalloproteinase-13 (MMP-13) has been shown to participate in the formation and diffusion of periapical bone lesion in chronic apical periodontitis. Sirtuin 1 (SIRT1) is a key regulator of inflammation in mammalian cells which suppresses the release of inflammatory mediators. This study aimed to explore the role of SIRT1 in regulating MMP-13 expression induced by P.e LPS in osteoblasts. P.e LPS stimulated MMP-13 expression in MC3T3-E1 cells. Knockdown of SIRT1 reinforced the increase of MMP-13mRNA expression induced by P.e LPS. SIRT1 activator resveratrol significantly reduced the expression of MMP-13 and SIRT1 inhibitor EX-527 enhanced the expression of MMP-13. Moreover, SIRT1 activation with resveratrol inhibited acetylation of NF-κB p65 and NF-κB transcriptional activity, which were enhanced by P.e LPS. In addition, NF-κB p65 was involved in P.e LPS-induced MMP-13 expression via directly binding to the MMP-13 promoter. However, SIRT1 activation significantly interfered with this binding. These findings strongly suggest that P.e LPS induces MMP-13 expression in osteoblasts, and SIRT1 suppresses this expression of MMP-13 through targeting NF-κB p65. This provides new insights into understanding the actions of SIRT1 on anti-inflammatory and anti-bone resorption activity.

Coccomyxa Gloeobotrydiformis Improves Learning and Memory in Intrinsic Aging Rats.

Declining in learning and memory is one of the most common and prominent problems during the aging process. Neurotransmitter changes, oxidative stress, mitochondrial dysfunction and abnormal signal transduction were considered to participate in this process. In the present study, we examined the effects of Coccomyxa gloeobotrydiformis (CGD) on learning and memory ability of intrinsic aging rats. As a result, CGD treated (50 mg/kg·d or 100 mg/kg ·d for a duration of 8 weeks) 22-month-old male rats, which have shown significant improvement on learning and spatial memory ability compared with control, which was evidently revealed in both the hidden platform tasks and probe trials. The following immunohistochemistry and Western blot experiments suggested that CGD could increase the content of Ach and thereby improve the function of the cholinergic neurons in the hippocampus, and therefore also improving learning and memory ability of the aged rats by acting as an anti-inflammatory agent. The effects of CGD on learning and memory might also have an association with the ERK/CREB signalling. The results above suggest that the naturally made drug CGD may have several great benefit as a multi-target drug in the process of prevention and/or treatment of age-dependent cognitive decline and aging process.

The neuroprotective effects of Coccomyxa gloeobotrydiformis on the ischemic stroke in a rat model.

Stroke is a major cause of mortality and the leading cause of permanent disability. In this study, we adopted the classic middle cerebral artery occlusion(MCAO) stroke model to observe the therapeutic effects of coccomyxa gloeobotrydiformis(CGD) on ischemic stroke, and discuss the underlying mechanisms. Low dose (50 mg/kg.day) and high dose (100 mg/kg.day) concentrations of the drug CGD were intragastrically administrated separately for 8 weeks. Infarct volumes, neurologic deficits and degree of stroke-induced brain edema were measured 24 hours after reperfusion. Furthermore, oxidative stress related factors (SOD and MDA), mitochondrial membrane potential, and apoptosis regulatory factors (mitochondrial Cyt-C, Bcl-2, Bax, and caspase-3) were all investigated in this research. We found that CGD attenuated cerebral infarction, brain edema and neurologic deficits; CGD maintained the mitochondrial membrane potential and decreased mitochondrial swelling. It also prevented oxidative damage by reducing MDA and increasing SOD. In addition, CGD could effectively attenuate apoptosis by restoring the level of mitochondrial Cyt C and regulating the expression of Bcl-2, Bax and caspase 3. These results revealed that CGD has a therapeutic effect on ischemic stroke, possibly by inducing mitochondrial protection and anti-apoptotic mechanisms.