Yao-Jen Liang

Amelioration of LPS-induced inflammation response in microglia by AMPK activation.

Adenosine 5′-monophosphate-activated protein kinase (AMPK) is a key regulator of cellular energy homeostasis via modulating metabolism of glucose, lipid, and protein. In addition to energy modulation, AMPK has been demonstrated to associate with several important cellular events including inflammation. The results showed that ENERGI-F704 identified from bamboo shoot extract was nontoxic in concentrations up to 80u2009μM and dose-dependently induced phosphorylation of AMPK (Thr-172) in microglia BV2 cells. Our findings also showed that the treatment of BV2 with ENERGI-F704 ameliorated the LPS-induced elevation of IL-6 and TNF-α production. In addition, ENERGI-F704 reduced increased production of nitric oxide (NO) and prostaglandin E2 (PGE2) via downregulating the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2), respectively. Moreover, ENERGI-F704 decreased activated nuclear translocation and protein level of NF-κB. Inhibition of AMPK with compound C restored decreased NF-κB translocation by ENERGI-F704. In conclusion, ENERGI-F704 exerts inhibitory activity on LPS-induced inflammation through manipulating AMPK signaling and exhibits a potential therapeutic agent for neuroinflammatory disease.

Astaxanthin Protects Steroidogenesis from Hydrogen Peroxide-Induced Oxidative Stress in Mouse Leydig Cells

Androgens, especially testosterone produced in Leydig cells, play an essential role in development of the male reproductive phenotype and fertility. However, testicular oxidative stress may cause a decline in testosterone production. Many antioxidants have been used as reactive oxygen species (ROS) scavengers to eliminate oxidative stress to protect steroidogenesis. Astaxanthin (AST), a natural extract from algae and plants ubiquitous in the marine environment, has been shown to have antioxidant activity in many previous studies. In this study, we treated primary mouse Leydig cells or MA-10 cells with hydrogen peroxide (H2O2) to cause oxidative stress. Testosterone and progesterone production was suppressed and the expression of the mature (30 kDa) form of StAR protein was down-regulated in MA-10 cells by H2O2 and cAMP co-treatment. However, progesterone production and expression of mature StAR protein were restored in MA-10 cells by a one-hour pretreatment with AST. AST also reduced ROS levels in cells so that they were lower than the levels in untreated controls. These results provide additional evidence of the potential health benefits of AST as a potential food additive to ease oxidative stress.

AMP-activated protein kinase activators in diabetic ulcers: from animal studies to Phase II drugs under investigation

Introduction: Diagnosed cases of diabetes have gradually increased year by year, and research on diabetes mellitus (DM) has attracted greater attention from the medical profession. Diabetic ulcers present persistent pain and the risk of bacterial infection. However, no promising treatment methods have been found. As a regulator of cellular energy balance, 5’ adenosine monophosphate-activated protein kinase (AMPK) has been suggested as a drug target for DM, including such drugs as metformin. Areas covered: This review summarizes the current research and clinical trials of AMPK activators on diabetic wound healing and diabetic ulcers. Furthermore, it discusses the feasibility of AMPK activators in the treatment of diabetic wounds. Expert opinion: Animal studies have demonstrated that AMPK activators are a potential treatment for diabetic ulcers. AMPK activators alleviate tissue inflammation and promote re-epithelialization in diabetic wounds. However, due to the complicated pathological mechanism of diabetic foot ulcers, AMPK activators should be combined with other approaches. The new strategies for combination therapy with AMPK activator may provide a therapeutic advantage for patients with diabetic ulcers.

Activation of AMP-Activated Protein Kinase by Adenine Alleviates TNF-Alpha-Induced Inflammation in Human Umbilical Vein Endothelial Cells.

The AMP-activated protein kinase (AMPK) signaling system plays a key role in cellular stress by repressing the inflammatory responses induced by the nuclear factor-kappa B (NF-κB) system. Previous studies suggest that the anti-inflammatory role of AMPK involves activation by adenine, but the mechanism that allows adenine to produce these effects has not yet been elucidated. In human umbilical vein endothelial cells (HUVECs), adenine was observed to induce the phosphorylation of AMPK in both a time- and dose-dependent manner as well as its downstream target acetyl Co-A carboxylase (ACC). Adenine also attenuated NF-κB targeting of gene expression in a dose-dependent manner and decreased monocyte adhesion to HUVECs following tumor necrosis factor (TNF-α) treatment. The short hairpin RNA (shRNA) against AMPK α1 in HUVECs attenuated the adenine-induced inhibition of NF-κB activation in response to TNF-α, thereby suggesting that the anti-inflammatory role of adenine is mediated by AMPK. Following the knockdown of adenosyl phosphoribosyl transferase (APRT) in HUVECs, adenine supplementation failed to induce the phosphorylation of AMPK and ACC. Similarly, the expression of a shRNA against APRT nullified the anti-inflammatory effects of adenine in HUVECs. These results suggested that the role of adenine as an AMPK activator is related to catabolism by APRT, which increases the cellular AMP levels to activate AMPK.

CIP2A is a poor prognostic factor and can be a diagnostic marker in papillary thyroid carcinoma.

Papillary thyroid carcinoma (PTC) is the most common type of thyroid carcinoma. CIP2A has recently been described as a prognostic marker in many cancers. In this study, we assessed the value of this novel prognostic marker in PTC. A total of 178 surgical specimens of both benign and malignant thyroid tumors were collected. Immunohistochemical staining for CIP2A, HBME‐1, galectin‐3, and CK19 was performed. Western blotting for CIP2A was also performed. CIP2A was expressed in 85.3% of malignant tumors and 12.1% of benign tumors. ROC analysis showed that the AUC for CIP2A was higher than those for other tumor markers. Western blotting showed that CIP2A expression was higher in PTC than in other tumors. Poor progression‐free survival was observed in the high‐CIP2A expression group. High CIP2A expression is a poor prognostic factor and can be a diagnostic marker in PTC. The presence of any two of the three indicated makers (CIP2A, galectin‐3, and HBME‐1) is strongly correlated with the diagnosis of PTC.

VEGF-D as a marker in the aid of malignant metastatic pleural effusion diagnosis.

Background:The sensitivity in cytology diagnosis of malignant metastatic pleural effusion (MMPE) is insufficient nowadays due to the similarity of the reactive mesothelial cells and malignant cells. Vascular endothelial growth factor (VEGF) is one of the key factors in tumor lymphangiogenesis and metastasis. Therefore, the aim of this study was to evaluate the value of VEGF and its homologs in the aid of MMPE diagnosis. Methods:A total of 217 pleural effusions samples were eligible for analysis. Among them, 81 malignant and 22 benign cases were made into the cell blocks for the immunocytochemical (ICC) staining of VEGF-A, VEGF-C, VEGF-D, VEGFR-2, and VEGFR-3 expression. Another 114 samples (41 malignant and 73 benign cases) were subjected to the ELISA test for the protein level of VEGF-D. Results:In a total of 156 MMPE, only VEGF-D expression by ICC stain was significantly different between malignant (92.6%) and benign cases (9.1%) with P<0.001 in either nuclear or cytoplasmic staining. Only 6 malignant cases showed negative stain results. In addition, 3 of the 4 lung small cell carcinoma were immunoreactive for VEGF-D. However, some lymphocytes also showed nuclear staining pattern of VEGF-D. In contrast, the ELISA test for the VEGF-D protein levels failed to demonstrate the difference between malignant and benign pleural effusions. Conclusions:Among VEGF homologs, MMPE from various kinds of tumor origin, VEGF-D showed 92.6% rate of positive expression. ICC stain of VEGF-D is a useful marker in the aid of MMPE diagnosis.

Adenine accelerated the diabetic wound healing by PPAR delta and angiogenic regulation

Abstract Wound healing is one of the major complications of diabetes, and problems with wound healing in diabetics often lead to amputation and even death. AMP‐activated protein kinase (AMPK) is a protein involved in intracellular metabolism. Activated AMPK can reduce visceral fat and cholesterol synthesis and even inhibit hepatic gluconeogenesis. Activation of AMPK has been widely used in the treatment of type II diabetes. We applied an AMPK activator (Adenine) to human fibroblasts and to the wounds of streptozotocin‐induced diabetic mice. We applied Adenine ointment to the wounds on 7 consecutive days and observed the healing status as well as activation of AMPK and angiogenic factors. Based on the appearance of the wounds, the results showed that after 7 days of treatment the wound area was smaller in the Adenine‐treated group relative to the control group. The results for tissue protein expression showed that, compared to the control group, angiogenic related protein, PPAR&dgr; were increased and receptor for advanced glycation endproducts (RAGE) was decreased in the Adenine‐treated group. Our studies indicate that Adenine has the potential to become a useful drug in the treatment of diabetic wound healing.

Correction: Effect of body mass index on diabetogenesis factors at a fixed fasting plasma glucose level

[This corrects the article DOI: 10.1371/journal.pone.0189115.].

High normotension is associated with future metabolic syndrome but not cardiovascular disease: A 10-year longitudinal study

Abstract Hypertension and prehypertension can increase the risk of developing cardiovascular disease (CVD) and diabetes. However, whether the harmful effects of high blood pressure (BP) are also seen with high normotension remains unknown. This 10-year longitudinal follow-up study aimed to investigate the relationships among normal-range BP, metabolic syndrome (MetS), and CVD. A total of 9133 nonmedicated normotensive participants, 4634 males and 4499 females, aged 60 years or older were enrolled in a standard health examination program at 2 academic hospitals and a health screening center in Taiwan. The study subjects were divided into 3 groups according to their BP. The systolic BP (SBP) ranges of groups 1, 2, and 3 were 91 to 100, 101 to 110, and 111 to 119u200ammHg, whereas the diastolic BP (DBP) ranges of groups 1, 2, and 3 were 51 to 60, 61 to 70, and 71 to 79u200ammHg, respectively. In the SBP3 group, both sexes had a higher odds ratio (OR) for having MetS or abnormal MetS components, except for triglycerides. Females in the DBP3 group had a higher OR for having MetS at baseline. After the follow-up period, the SBP3 group had a significantly higher hazard ratio (HR) for developing MetS. Males in the DBP3 group and females in the DBP2 and DBP3 groups had a significantly higher HR for developing MetS. Neither the SBP3 group nor the DBP3 group had a higher HR for developing nonfatal CVD. In the Kaplan-Meier analysis, SBP and DBP in both sexes showed statistical significance as predictors of MetS, but not of nonfatal CVD. High normotensive elderly individuals have an elevated risk of developing MetS at baseline and within 10 years of follow-up, but they are not at increased risk of CVD. Preventive interventions, such as life-style modification, should be offered early even to the apparently healthy elderly.

Peroxisome Proliferator-Activated Receptor Delta Agonists and AMP-Activated Protein Kinase Activators Reverse Interleukin 6-Inhibited Erythropoietin Receptor Expression

BACKGROUND: Interleukin-6 (IL-6) was shown to inhibit erythropoietin receptor (EpoR) expression in erythroid progenitor cells. The anti-inflammatory effects of peroxisome proliferator-activated receptor (PPAR) agonists and AMP-activated protein kinase (AMPK) activators have been proven in previous studies. This study is going to evaluate the effects of PPAR agonists and AMPK activators on IL-6- induced inhibition of EpoR expression and possible mechanisms. METHODS: Human erythroleukemia cells (K562) were incubated with IL-6 (5 ng/mL) for 18 hours in the presence and then absence of an AMPK activator HybriMore (200 μM) and peroxisome proliferatoractivated receptor δ (PPARδ) agonists L-165,041 (1 μM). The expression of EpoR and two downstream substances of AMPK, phosphorylated acetyl-CoA carboxylase (ACC), and glycogen synthase kinase (GSK) in K562 cells was measured. RESULTS: IL-6 significantly inhibited EpoR expression in K562 cells. HybriMore (200 μM) and L-165,041 (1 μM) significantly reversed IL-6 induced inhibition of EpoR expression with similar potency. IL-6 also significantly inhibited phosphorylated glycogen synthase kinase 3 (GSK3) and ACC expression. HybriMore showed no effect on IL-6-induced inhibition of phosphorylated GSK3 and ACC. L-165,041, however, reversed the inhibition of ACC, but had no effect on GSK3. CONCLUSION: Both PPAR agonists and AMPK activators significantly reverse IL-6-inhibited EpoR expression in K562 cells. The effect of AMPK activators may have no relationship with ACC or GSK3.