Expression Of PRKAA1 Research Articles

PRKAA1 predicts prognosis and is associated with immune characteristics in gastric cancer.

PRKAA1 is the α-subunit of 5-AMP-activated protein kinase. This study aimed to investigate the role of PRKAA1 expression with multiple clinical parameters, the overall survival rate, blood indexes, and immune infiltration in gastric cancer (GC) patients. We investigated PRKAA1 expression data in GC patients using ELISA, protein atlas, UALCAN, and GEPIA. PRKAA1 expression was associated with immune cell infiltration, and immune cell types were analyzed with the TIMER, DICE, and protein atlas databases. We compared the level of PRKAA1 expression based on the clinical features of GC patients (n = 345). GC patients were divided into two groups based on PRKAA1 expression, and the lymphocyte subsets, overall survival rate, and clinical parameters were compared with peripheral blood mononuclear cell and biochemical indexes. PRKAA1 was highly expressed in the serum of GC patients compared with that of healthy individuals. GC patients with distant metastases, a later TNM stage, and stage IV in UICC exhibited higher PRKAA1 expression. PRKAA1 expression was significantly correlated with circulating T cells. The protein atlas and DICE database results confirmed that PRKAA1 was closely associated with T cells in a single-cell cluster. Furthermore, GC patients with low PRKAA1 expression had better OS rates. PRKAA1 may serve as a potential prognostic biomarker for GC and have an association with immune infiltrates.

Anti-inflammatory Effects of Gallotannin in Combination With Lactobacillus plantarum in a DSS-Induced Colitis Mouse Model

ObjectivesTo establish the synergistic effects of the pre/probiotics on intestinal inflammation and to elucidate the underlying mechanisms, we investigated the anti-inflammatory effects of Gallotannin (TA) and Lactobacillus plantarum (LP) in LPS-treated cells and DSS-treated mice. We hypothesized that simultaneous intake of TA and LP may modulate the intestinal microbiota and increase the conversion rate of TA into its metabolites, which have potent anti-inflammatory properties due to their regulation of the AMPK/mTOR axis in colitis. MethodsMice were given two cycles of DSS (2.5% for 7 days) to induce chronic colitis with oral gavage of gallotannin (0.8 mg/mouse) every other day for 4 weeks. At the end of each DSS cycle, L. plantarum (108 CFU/100 μL; OD600 = 0.6) was fed for 3 days. Body weight, colon length, and histopathological assessment were all assessed on the final day, and blood, feces, and colon samples were taken. ResultsIn LPS-treated macrophage RAW 264.7, TA metabolized by LP significantly decreased the levels of IL-6 and TNF-α. In an experimental murine model of UC, we found that the combination of LP and TA improved weight gain, gut length, enlarged spleen, and histological scores while lowering the levels of TNF-α, lipocalin-2, MPO, IFN-γ, IL-17, and IL-6 in DSS-treated mice. Furthermore, colonic mRNA expression levels of Pik3r1, Akt1, and mTor were reduced in the groups that received both LP and TA. The expression of Prkaa1 (AMPKa1) and Map1lc3a (LC3) mRNA increased considerably after the co-administration of LP and TA, compared to the DSS control group. Additionally, LP and TA decreased the ratio of p-mTOR/mTOR protein expression while increasing the p-AMPK/AMPK ratio in DSS-treated mice. Mouse feces were used to measure compositional changes in the gut microbiota. Compared to the DSS control, the combination of LP and TA increased the levels of probiotics, such as Lactobacillus spp., Lactobacillus reuteri, and Lactococcus lactis in DSS-treated mice. ConclusionsSimultaneous intake of LP and TA showed a synergistic effect in attenuating mucosal damage and decreasing inflammatory cytokines by modulating the AMPK/mTOR axis and restoring intestinal microbiota imbalance. Funding SourcesNational Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2020R1G1A1099851) and Pusan National University Research Grant, 2020.

Inhibition of miR-130b-3p restores autophagy and attenuates intervertebral disc degeneration through mediating ATG14 and PRKAA1.

Oxidative stress-induced autophagy dysfunction is involved in the pathogenesis of intervertebral disc degeneration (IVDD). MicroRNAs (miRNAs) not only have been regarded as important regulators of IVDD but also reported to be related to autophagy. This research was aimed to explore the role of miR-130b-3p in IVDD and its regulation on autophagy mechanism. The miR-130b-3p expression in the patient's degenerative nucleus pulposus (NP) samples and rat NP tissues was detected by qRT-PCR and FISH assay. The miR-130b-3p was knocked down or overexpressed in the human NP cells by lentivirus transfection. TBHP was used to induce oxidative stress in the human NP cells. Apoptosis, senescence, and autophagy were evaluated by flow cytometry, β-gal staining, immunofluorescence, electron microscopy, and Western blot in the miR-130b-3p knocked down human NP cells under TBHP treatment. The relationship between the miR-130b-3p and ATG14 or PRKAA1 was confirmed by luciferase assay. The siRNA transfection was used to knock down the ATG14 and PRKAA1 expression, and then the human NP cells functions were further determined. In the in vivo experiment, the IVDD rat model was constructed and an adeno-associated virus (AAV)-miR-130b-3p inhibitor was intradiscally injected. After that, MRI and histological staining were conducted to evaluate the role of miR-130b-3p inhibition in the IVDD rat model. We found that the miR-130b-3p was upregulated in the degenerative NP samples from humans and rats. Interestingly, the inhibition of miR-130b-3p rescued oxidative stress-induced dysfunction of the human NP cells, and miR-130b-3p inhibition upregulated autophagy. Mechanistically, we confirmed that the miR-130b-3p regulated the ATG14 and PRKAA1 directly and the knockdown of the ATG14 or PRKAA1 as well as the treatment of autophagy inhibitor blockaded the autophagic flux and reversed the protective effects of miR-130b-3p inhibition in the TBHP-induced human NP cells. Furthermore, the inhibition of the miR-130b-3p via AAV- miR-130b-3p injection ameliorated the IVDD in a rat model. These data demonstrated that the miR-130b-3p inhibition could upregulate the autophagic flux and alleviate the IVDD via targeting ATG14 and PRKAA1.The translational potential of this article: The suppression of miR-130b-3p may become an effective therapeutic strategy for IVDD.

Impact of Different Physical Exercises on the Expression of Autophagy Markers in Mice

Although physical exercise-induced autophagy activation has been considered a therapeutic target to enhance tissue health and extend lifespan, the effects of different exercise models on autophagy in specific metabolic tissues are not completely understood. This descriptive investigation compared the acute effects of endurance (END), exhaustive (ET), strength (ST), and concurrent (CC) physical exercise protocols on markers of autophagy, genes, and proteins in the gastrocnemius muscle, heart, and liver of mice. The animals were euthanized immediately (0 h) and six hours (6 h) after the acute exercise for the measurement of glycogen levels, mRNA expression of Prkaa1, Ppargc1a, Mtor, Ulk1, Becn1, Atg5, Map1lc3b, Sqstm1, and protein levels of Beclin 1 and ATG5. The markers of autophagy were measured by quantifying the protein levels of LC3II and Sqstm1/p62 in response to three consecutive days of intraperitoneal injections of colchicine. In summary, for gastrocnemius muscle samples, the main alterations in mRNA expressions were observed after 6 h and for the ST group, and the markers of autophagy for the CC group were increased (i.e., LC3II and Sqstm1/p62). In the heart, the Beclin 1 and ATG5 levels were downregulated for the ET group. Regarding the markers of autophagy, the Sqstm1/p62 in the heart tissue was upregulated for the END and ST groups, highlighting the beneficial effects of these exercise models. The liver protein levels of ATG5 were downregulated for the ET group. After the colchicine treatment, the liver protein levels of Sqstm1/p62 were decreased for the END and ET groups compared to the CT, ST, and CC groups. These results could be related to diabetes and obesity development or liver dysfunction improvement, demanding further investigations.

Therapeutic inhibition of miR-802 protects against obesity through AMPK-mediated regulation of hepatic lipid metabolism.

Background: The host-parasite relationship is based on subtle interplay between parasite survival strategies and host defense mechanisms. It is well known that helminth infection, which afflicts more than one billion people globally, correlates with a decreased prevalence of obesity. Dissecting the underlying mechanisms can provide new targets for treating obesity from the host-parasite interaction perspective.Methods: C57BL/6 mice received a normal or high-fat diet (HFD) with or without Sjp40 (one main component of schistosome-derived soluble egg antigens) treatment. Both the loss and gain-of-function experiments by the inhibitor suppression and lentivirus treatment of miR-802 were utilized to elucidate the role of miR-802/AMPK axis in host lipid metabolism. Hepatocyte lipogenesis assay and metabolic parameters were assessed both in vivo and in vitro. The potential interactions among Sjp40, CD36, miR-802, Prkab1, and AMPK were clarified by pull-down, miRNA expression microarray, quantitative RT-PCR, dual-luciferase reporter assay, and western blotting analysis.Results: We showed a link between decreased miR-802 and impaired lipid metabolism in Schistosoma japonicum infected mice. The decreased miR-802 promotes murine Prkab1 or human Prkaa1 expression, respectively, which increases levels of phosphorylated AMPK, resulting in a decrease in hepatic lipogenesis. Also, injection with schistosome-derived soluble egg antigens (SEA) attenuated metabolism. We demonstrated that Sjp40 as a main component of SEA interacted with CD36 on hepatocytes to inhibit miR-802, resulting in the activation of AMPK pathway and subsequent attenuation of lipogenesis.Collectively: Our study reveals the significant role of miR-802/AMPK axis in hepatic lipid metabolism and identifies the therapeutic potential of Sjp40 in treating obesity-related fatty liver.

LINC00473/miR-497-5p Regulates Esophageal Squamous Cell Carcinoma Progression Through Targeting PRKAA1

Background: Esophageal squamous cell carcinoma (ESCC) is one of the esophageal cancers known as an aggressive malignant tumor. Long noncoding RNAs (lncRNAs) can be involved in the progression and development of cancers. lncRNA LINC00473 (LINC00473) was reported to exert an oncogenic influence on diverse cancers. However, neither the biological function nor the underlying mechanism of LINC00473 has been explored in ESCC. Aim of the Study: The aim of investigation is to explore the role of LINC00473 in ESCC. Methods: The expression of LINC00473, miR-497-5p, and protein kinase AMP-activated alpha 1 catalytic subunit (PRKAA1) was detected by reverse-transcription quantitative polymerase chain reaction assay. Cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays were carried out to measure cell proliferation. Cell migration was tested by transwell assay. Western blot assay was performed to examine the protein expression of PRKAA1, E-cadherin, N-cadherin, and Vimentin. The binding capacity between miR-497-5p and LINC00473 (or PRKAA1) was, respectively, studied by luciferase reporter and RNA immunoprecipitation assays. Pearson correlation analysis was adopted to analyze the correlation between miR-497-5p (or LINC00473) and PRKAA1. Results: LINC00473 presented much higher expression and LINC00473 suppression restrained the proliferation, migration, and epithelial-mesenchymal transition (EMT) process in ESCC cells. MiR-497-5p presented lower expression, binding with and negatively regulated by LINC00473 in ESCC. PRKAA1 was confirmed as a downstream target gene for miR-497-5p. PRKAA1 could combine with miR-497-5p, and LINC00473 knockdown or miR-497-5p overexpression downregulated the mRNA and protein expression of PRKAA1. At last, the inhibitory effects of LINC00473 knockdown on proliferation, migration, and EMT process were reversed by PRKAA1 overexpression in vitro and in vivo. Conclusions: LINC00473 regulates ESCC progression through miR-497-5p/PRKAA1 axis, which provides a new therapeutic strategy for ESCC patients.

Involvement of NF-κB signaling pathway in the regulation of PRKAA1-mediated tumorigenesis in gastric cancer

AMP-activated alpha 1 catalytic subunit (PRKAA1) is one of the subunits of the mammalian 5′-AMP-activated protein kinase (AMPK) playing an important role in maintaining intracellular energy metabolism and associating with the risk of gastric cancer (GC). This paper aims to uncover the influences of PRKAA1 on the tumorigenesis of GC, as well as the underlying mechanisms. We found that Helicobacter pylori (H. pylori) infection markedly increased p-NF-κBp50 and NF-κBp50 expression, along with the PRKAA1 expression, which was inhibited by NF-κBp50 knockdown. NF-κBp50 and PRKAA1 expression were lower in non-tumor gastric tissues compared with that in GC tumor tissues. Up-regulation of PRKAA1 expression was correlated with poor survival in GC patients. MKN-45 and BGC-823 cells stably knockdown of PRKAA1 were transplanted into nude mice and observed the decreased cell metastasis in the lungs. PRKAA1 knockdown in GC cells showed significant decreases in the cell invasion and migration and inhibited MMP-2 expression and NF-κB activation, whereas PRKAA1 involved in NF-κBp50 mediated GC cell invasion and migration. In conclusion, our findings suggest the involvement of NF-κBp50 in the regulation of PRKAA1 in GC tumorigenesis.

Maternal Overfeeding during Lactation Impairs the Metabolic Response to Fed/Fasting Changing Conditions in the Postweaning Offspring.

The metabolic response to fed/fasting changing conditions at early age in rats with different predisposition to obesity-related alterations due to maternal conditions during the perinatal period is studied. Offspring of dams made obese by a cafeteria diet and moved to a normal-fat diet 1 month before gestation (O-PCaf, with an apparently normal phenotype in adulthood), and offspring of cafeteria diet-fed dams during lactation (O-CAF, with a thin-outside-fat inside phenotype), together with the offspring of control dams (O-C), are studied at early age. Fasting is associated with downregulation of lipogenesis-related genes in liver and rpWAT, and upregulation of genes related to lipolysis and fatty acid uptake in rpWAT in O-C animals. The response to fed/fasting conditions is impaired in O-CAF, but not in O-PCaf animals. The fasting-induced increase in the expression of Prkaa1 in liver and rpWAT, and the corresponding increase of hepatic AMPKα1 protein levels of O-C animals are attenuated in O-CAF rats, while no alterations are found in O-PCaf animals versus controls. Maternal intake of a cafeteria diet during lactation causes early alterations in the offspring, impairing their metabolic flexibility in response to fed/fasting changing conditions, which may contribute to hindering energy homeostasis maintenance.

Bta-miR-152 affects intracellular triglyceride content by targeting the UCP3 gene.

According to our previous studies, bta-miR-152, PRKAA1 and UCP3 are differentially expressed in mammary gland tissues of high milk fat and low milk fat cows, and the trend in bta-miR-152 expression is opposite from those of PRKAA1 and UCP3. To further identify the function and regulatory mechanism of bta-miR-152 in milk fat metabolism, we investigated the effect of bta-miR-152 on cellular triglyceride content in bovine mammary epithelial cells cultured in vitro, on the basis of bta-miR-152 overexpression and inhibition assays. The target genes of bta-miR-152 were identified through qPCR, Western blotting and dual luciferase reporter gene detection. Compared with that in the control group, the expression of UCP3 was significantly lower in the bta-miR-152 mimic group, the expression of PRKAA1 was decreased, and the intracellular TAG content was significantly increased. After transfection with bta-miR-152 inhibitor, the expression of UCP3 increased significantly, and the expression of PRKAA1 decreased, but the difference was not significant; in addition, the intracellular TAG content decreased significantly. Therefore, we concluded that bta-miR-152 affects the intracellular TAG content by targeting UCP3.

The Role of AMPK in Chemotherapy Response in AML

Introduction: Acute myeloid leukemia is an aggressive malignancy characterized by relapse and resistance to therapy. When treated with standard chemotherapy 60-80% of patients will achieve a remission however most will suffer a relapsed and once relapsed the disease is much more resistant to repeated treatment. Despite the central role of resistance little is known about the mechanism of chemotherapy responsiveness in AML. Our laboratory has previous shown a metabolic shift occurs in AML cells following chemotherapy exposure with increased mitochondrial oxygen consumption leading to resistance. Adenosine monophosphate activated protein kinase (AMPK) is a central metabolic regulator and leading candidate to coordinate this metabolic shift. However, the role of AMPK in chemotherapy response in AML is unknown.Methods: A Cas9 expressing AML model was generated and partially infected with a lentiviral vector coding an sgRNA targeting the alpha 1 subunit of AMPK, PRKAA1. This subunit was chosen as cell line and clinical expression datasets demonstrated that AML cells expressed little or none of the second alpha subunit PRKAA2. PRKAA1 deleted clones (AMPK KO) were isolated and loss of PRKAA1 expression and AMPK activity were confirmed. AMPK KO cells were characterized for responsiveness to chemotherapy, metabolic inhibitors and the DNA damage response.Results: Consistent with a role in response to chemotherapy AML cells treated with cytarabine demonstrated a significant increase in AMPK activation. When partially AMPK deleted populations were treated with cytarabine or doxorubicin a significant enrichment was seen in the deleted cells suggesting that loss of AMPK promotes therapy resistance. To confirm this finding isogeneic AML cell lines were treated with chemotherapy. AMPK KO cells were significantly more resistant to doxorubicin and cytarabine compared to isogeneic controls expressing an sgRNA targeting the ROSA26 (ROSA KO) safe harbor locus. When the mechanism of this resistance was explored AMPK KO cells were found to have diminished H2AX, p53 and p21 induction following exposure to doxorubicin culminating in a decrease in apoptosis. To assess if this resistant phenotype was present in vivo, AMPK KO or ROSA KO cells were tail vein injected into sub-lethally irradiated mice. Upon confirmation of engraftment mice were treated with a combination of cytarabine and doxorubicin. AMPK KO mice had a significantly decreased survival following treatment then treated ROSA controls. Additionally, AMPK KO and ROSA KO cells were treated with the glycolysis inhibitor 2-Deoxyglucose, the autophagy inhibitor chloroquine and the fatty acid oxidation inhibitor extomoxir. In all cases AMPK KO cells were significantly more resistant to these agents than the ROSA KO cells suggesting a proapoptotic role of AMPK following exposure to metabolic inhibitors. Finally, the clinical relevance of these findings was assessed by examining outcomes of AML patients treated with chemotherapy in relationship to their levels of PRKAA1 expression. Patients with the lowest expression of PRKAA1 had a significantly worse overall survival consistent with our findings.Conclusions: In AML cells activated AMPK provides pro-apoptotic signaling in response to DNA damaging agents allowing incorporation of metabolic status into cell fate decisions following treatment. Utilization of metabolic inhibitors that activate AMPK in combination with chemotherapy should be explored in the treatment of AML. DisclosuresPardee:Karyopharm: Research Funding; Novartis: Speakers Bureau; Rafael Pharmaceuticals: Employment; Celgene: Speakers Bureau; Amgen: Speakers Bureau.

Do polymorphisms in protein kinase catalytic subunit alpha-1 gene associated with cancer susceptibility? a meta-analysis and systematic review

BackgroundCurrently, several studies have demonstrated that PRKAA1 polymorphisms conduce to the development of cancer. PRKAA1 gene encodes the AMP-activated protein kinase summit-α1, and plays an important role in cell metabolism. Thus, we performed a systematic review and meta-analysis of all enrolled eligible case-control studies to obtain a precise correlation between PRKAA1 polymorphism and cancer susceptibility.MethodsExtensive retrieve was performed in Web of Science, Google Scholar, PubMed, EMbase, CNKI and Wanfang databases up to August 26, 2018. Odds ratios (ORs) and 95% CIs were performed to evaluate the overall strength of the associations in five models, as well as in subgroup analyses, stratified by ethnicity, cancer type or source of control. Q-test, Egger’s test and Begg’s funnel plot were applied to evaluate the heterogeneity and publication bias. In-silico analysis was performed to demonstrate the relationship of PRKAA1 expression correlated with cancer tissues and survival time.ResultsTwenty-two case-control studies from 14 publications were enrolled, with 17,068 cases and 20,871 controls for rs13361707, and 2514 cases and 3193 controls for rs10074991. Overall, we identified that the PRKAA1 rs13361707 polymorphism is not significantly associated with cancer susceptibility under all five genetic models. For rs10074991, we revealed a significant decrease risk in allelic comparison model (B vs. A: OR = 0.774, 95% CI = 0.642–0.931, PAdjust = 3.376*10− 2), heterozygote comparison model (BA vs. AA: OR = 0.779 95%CI = 0.691–0.877, PAdjust = 9.86*10− 10;), and dominant genetic model (BB + BA vs. AA: OR = 0.697 95%CI = 0.533–0.912, PAdjust = 4.211*10− 2;). Evidence from TCGA database and GTEx projects indicated that the expression of PRKAA1 in gastric cancer tissue is higher, compared to normal stomach tissue, as well as it in breast cancer and esophageal squamous cell carcinoma. However, the Kaplan-Meier estimate showed that there is no significant difference of OS and RFS between the low and high PRKAA1 TPM groups in gastric cancer, breast cancer, and esophageal carcinoma.ConclusionsTo sum up, PRKAA1 rs13361707 polymorphism is not participant with the increased risk of cancer, while the A allele of PRKAA1 rs10074991 revealed a significant decrease risk.

Allyl Isothiocyanate Exhibits No Anticancer Activity in MDA-MB-231 Breast Cancer Cells.

It was reported recently that allyl isothiocyanate (AITC) could inhibit various types of cancer cell growth. In the present study, we further investigated whether AITC could inhibit the growth of human breast cancer cells. Unexpectedly, we found that AITC did not inhibit, rather slightly promoted, the proliferation of MDA-MB-231 breast cancer cells, although it did have inhibitory effect on MCF-7 breast cancer cells. Cytofluorimetric analysis revealed that AITC (10 µM) did not induce apoptosis and cell cycle arrest in MDA-MB-231 cells. In addition, AITC significantly (p < 0.05) increased the expression of BCL-2 and mTOR genes and Beclin-1 protein in MDA-MB-231 cells. No significant changes in expression of PRKAA1 and PER2 genes, Caspase-8, Caspase-9, PARP, p-mTOR, and NF-κB p65 proteins were observed in these AITC-treated cells. Importantly, AITC displayed cytotoxic effect on MCF-10A human breast epithelial cell line. These observations suggest that AITC may not have inhibitory activity in MDA-MB-231 breast cancer cells. This in vitro study warrants more preclinical and clinical studies on the beneficial and harmful effects of AITC in healthy and cancer cells.

LINC00152/miR-139-5p regulates gastric cancer cell aerobic glycolysis by targeting PRKAA1

Gastric cancer is one of the most common cancers in the world and glycolysis is a major feature of gastric cancer. MicroRNAs (miRNAs) involve in gastric cancer cell proliferation, glycolysis and other cellular processes. MiR-139-5p is reported as a tumor suppressor in cancers, however, the role of miR-139-5p including glycolytic metabolism is unclear in gastric cancer. So, the purpose of the present study is to elucidate the underlying mechanism in gastric cancer metabolism mediated by miR-139-5p. Our results revealed that miR-139-5p inhibited glycolysis by regulating AMP-activated, alpha 1 catalytic subunit (PRKAA1) expression in gastric cancer cells. We also found that miR-139-5p was down-regulated by long intergenic non-coding RNA 152 (LINC00152) in gastric cancer cells. Our results indicate that LINC00152/miR-139-5p facilitates gastric cancer cell glycolysis by regulating PRKAA1 expression.

Correlation between protein kinase catalytic subunit alpha-1 gene rs13361707 polymorphism and gastric cancer susceptibility in asian populations.

A single nucleotide polymorphism (SNP) of the protein kinase catalytic subunit alpha-1 gene (PRKAA1) that confers susceptibility to gastric cancer (GC) was identified by genome-wide association in several case-control studies. However, the results remained controversial and ambiguous. Therefore, we performed a larger meta-analysis to confirm this association. We searched the PubMed, Embase, WanFang, and CNKI databases, without any restriction on language, covering all papers published until Feb 22, 2017. Overall, 14 case-control studies with 14,485 cases and 14,792 controls were retrieved based on the search criteria. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to quantify the strength of the association. Publication bias was assessed by Egger’s and Begg’s tests. We found that the PRKAA1 rs13361707 C/T polymorphism had no association with GC risk in any of the pooled genetic models (for example, the T-allele vs. C-allele allelic contrast model yielded the following estimates: OR = 0.87, 95% CI = 0.73–1.05, Pheterogeneity = 0.000). Furthermore, in analyses stratified by either source of control or geographical origin of subjects, a statistically significant inverse relationship was detected between PRKAA1 rs13361707 C/T polymorphism and GC risk. No obvious evidence of publication bias was detected in the pooled meta-analysis. Furthermore, we observed that individuals carrying T-allele (TT or TC) genotypes had a lower expression of PRKAA1. Our present study indicated that PRKAA1 rs13361707 C/T was not significantly associated with GC risk, despite few positive results in the subgroups.

SiRNA-mediated AMPK.ALPHA.1 subunit gene PRKAA1 silencing enhances methylmercury toxicity in HEK293 cells

The environmental pollutant methylmercury is a potent neurotoxin. The mechanisms of toxicity and biological defense remain largely unknown. We found that inhibiting the expression of PRKAA1 (AMPKalpha1), an activated subunit of AMP-activated protein kinase (AMPK), increased susceptibility of HEK293 cells to methylmercury toxicity. Treatment of the cells with AICAR (5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside), an AMPK activator, reduced the methylmercury toxicity. Here, we suggest for the first time that the activation (phosphorylation) of AMPK may play an important role in reducing the toxicity of methylmercury.