Methyl ferulic acid ameliorates ethanol-induced L02 cell steatosis through microRNA-378b-mediated CaMKK2-AMPK pathway / 中国中药杂志

Alcoholic liver disease(ALD), with its increasing morbidity and mortality, has seriously and extensively affected the health of people worldwide. Methyl ferulic acid(MFA) has been proven to significantly inhibit alcohol-induced lipid production in L02 cells through the AMP-activated protein kinase(AMPK) pathway, but its in-depth mechanism remains unclear. This study aimed to further clarify the mechanism of MFA in improving lipid accumulation in L02 cells through the microRNA-378b(miR-378b)-mediated calcium/calmodulin-dependent protein kinase kinase 2(CaMKK2)-AMPK signaling pathway based on existing researches. L02 cells were induced by 100 mmol·L~(-1) ethanol for 48 h to establish the model of ALD in vitro, and 100, 50, and 25 μmol·L~(-1) concentration of MFA was treated. MiR-378b plasmids(containing the overexpression plasmid-miR-378b mimics, silence plasmid-miR-378b inhibitor, and their respective negative control-miR-378b NCs) were transfected into L02 cells by electroporation to up-regulate or down-regulate the levels of miR-378b in L02 cells. The levels of total cholesterol(TC) and triglyceride(TG) in cells were detected by commercial diagnostic kits and automatic biochemical analyzers. The expression levels of miR-378b in L02 cells were detected by real-time quantitative polymerase chain reaction(qRT-PCR). CaMKK2 mRNA levels were detected by PCR, and protein expressions of related factors involved in lipid synthesis, decomposition, and transport in lipid metabolism were detected by Western blot. The results displayed that ethanol significantly increased TG and TC levels in L02 cells, while MFA decreased TG and TC levels. Ethanol up-regulated the miR-378b level, while MFA effectively inhibited the miR-378b level. The overexpression of miR-378b led to lipid accumulation in ethanol-induced L02 cells, while the silence of miR-378b improved the lipid deposition induced by ethanol. MFA activated the CaMKK2-AMPK signaling pathway by lowering miR-378b, thus improving lipid synthesis, decomposition, and transport, which improved lipid deposition in L02 cells. This study shows that MFA improves lipid deposition in L02 cells by regulating the CaMKK2-AMPK pathway through miR-378b.

Effects of AMP-activated Protein Kinase Activating Compounds and Its Mechanism / 영남의대학술지

AMP-activated protein kinase (AMPK) is an important cellular fuel sensor. Its activation requires phosphorylation at Thr-172, which resides in the activation loop of the alpha1 and alpha2 subunits. Several AMPK upstream kinases are capable of phosphorylating AMPK at Thr-172, including LKB1 and CaMKKbeta (Ca2+/calmodulin-dependent protein kinase kinasebeta). AMPK has been implicated in the regulation of physiological signals, such as in the inhibition of cholesterol fatty acid, and protein synthesis, and enhancement of glucose uptake and blood flow. AMPK activation also exhibits several salutary effects on the vascular function and improves vascular abnormalities. AMPK is modulated by numerous hormones and cytokines that regulate the energy balance in the whole body. These hormone and cytokines include leptin, adiponectin, ghrelin, and even thyroid hormones. Moreover, AMPK is activated by several drugs and xenobiotics. Some of these are in being clinically used to treat type 2 diabetes (e.g., metformin and thiazolidinediones), hypertension (e.g., nifedipine and losartan), and impaired blood flow (e.g., aspirin, statins, and cilostazol). I reviewed the precise mechanisms of the AMPK activation pathway and AMPK-modulating drugs.

AMP-activated protein kinase Activating Agent and Its Implication

AMP-activated protein kinase (AMPK) is an important cellular fuel sensor. Activation of AMPK requires phosphorylation at threonine (Thr)-172, which resides in the activation loop of the alpha1 and alpha2 subunits. Several AMPK upstream kinases are capable of phosphorylating AMPK at Thr-172, including LKB1 and CaMKKbeta. AMPK has been implicated in the regulation of physiological signals, such as inhibition of cholesterol, fatty acid, protein synthesis, and enhancement of glucose uptake and blood flow. AMPK activation also exhibits several salutary effects on vascular function and improves vascular abnormalities. AMPK is activated by numerous drugs and xenobiotics. Some of these are in clinical use for the treatment of type 2 diabetes (e.g., metformin and thiazolidinediones), hypertension (e.g., nifedipine and losartan), and impaired blood flow (e.g., aspirin, statins, and cilostazol). Plant-derived xenobiotics or nutraceuticals that were claimed to have health benefits in diabetes or cancer have been reported to activate AMPK. These include resveratrol from red wine, epigallocatechin gallate from green tea, capsaicin from peppers, berberine, which is a yellow dye of the genus berberis, genistein from soy bean, and ginsenoside from ginseng panax. AMPK is also modulated by numerous hormones and cytokines that regulate energy balance at the whole body level, including leptin, adiponectin, ghrelin, and even thyroid hormones. This work shows that the precise mechanisms of AMPK kinase and AMPK interaction.

Effects of W-7 on the expression of GRP78 and neuronal apoptosis in immature rat hippocampus after status convulsion / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the effects of the calmodulin inhibitor W-7 on the expression of the key marker of ERS GRP78 and neuronal apoptosis in the immature rat hippocampus after status convulsion (SC).</p><p><b>METHODS</b>One hundred and seventeen male Sprague-Dawley rats aged 19-21 days were randomly divided into three groups: normal saline control (control), SC with and without W-7 pretreatment. Each of the 3 groups was further subdivided into subgroups sacrificed at 4, 24 and 48 hrs. SC model was prepared using lithium-pilocarpine. GRP78 mRNA expression in the hippocampus was detected by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). GRP78 protein was ascertained by immunohistochemistry. Neuronal apoptosis was observed with TdT-mediated dUTP nick end labeling (TUNEL).</p><p><b>RESULTS</b>The expression of GRP78 mRNA was significantly increased in the non-pretreated SC group compared with the control group 24 hrs after injection of saline or lithium-pilocarpine (P<0.01), and the expression of GRP78 protein also increased markedly in the seizure group compared with the control group 24 and 48 hrs after the injection (P<0.01). The expression of GRP78 mRNA and protein in the W-7 pretreatment group was significantly higher than both the control and the non-pretreated seizure groups 24 and 48 hrs after injection. The TUNEL positive cells in the hippocampus CA1 in the non-pretreated SC group 24 and 48 hrs after injection (21.0 ± 2.5 and 29.4 ± 2.8, respectively) were increased compared to the control group (7.1 ± 1.4 and 7.3 ± 1.6, respectively; P<0.01). W-7 pretreatment decreased TUNEL positive cells to 15.0 ± 2.5 and 20.0 ± 2.9 at 24 and 48 hrs after injection compared to the non-pretreated seizure group (P<0.01), but the number of TUNEL positive cells in the W-7 pretreatment group remained significantly greater than in the control group (P<0.01).</p><p><b>CONCLUSIONS</b>W-7 may up-regulate the expression of GRP78 and reduce the number of apoptotic neurons, thus provides a neuroprotective effect against brain damage following SC.</p>