Genotoxic effects induced by iprodione and tebuconazole in meristematic cells of Allium cepa: responses dependent on concentration and exposure time.

The present work explores the genotoxicity of the fungicides iprodione (IP) and tebuconazole (TB) using the Allium cepa assay as an in vivo biological model. Both short-term and long-term exposures were studied, revealing concentration- and time-dependent cytological and genotoxic effects. IP exhibited genotoxicity over a wider concentration range (5-50 µg/ml) and required 30 h of exposure, while TB showed genotoxicity at higher concentrations (10 and 30 µg/ml) within a 4-h exposure period. The study highlights the importance of assessing potential risks associated with fungicide exposure, including handling, disposal practices, and concerns regarding food residue. Moreover, the research underscores the genotoxic effects of IP and TB on plant cells and provides valuable insights into their concentration and time-response patterns.

Iprodione induces hepatotoxicity in zebrafish by mediating ROS generation and upregulating p53 signalling pathway.

Iprodione is an effective and broad-spectrum fungicide commonly used for early disease control in fruit trees and vegetables. Due to rainfall, iprodione often finds its way into water bodies, posing toxicity risks to non-target organisms and potentially entering the human food chain. However, there is limited information available regarding the developmental toxicity of iprodione specifically on the liver in existing literature. In this study, we employed larval and adult zebrafish as models to investigate the toxicity of iprodione. Our findings revealed that iprodione exposure led to yolk sac edema and increased mortality in zebrafish. Notably, iprodione exhibited specific effects on zebrafish liver development. Additionally, zebrafish exposed to iprodione experienced an overload of reactive oxygen species, resulting in the upregulation of p53 gene expression. This, in turn, triggered hepatocyte apoptosis and disrupted carbohydrate/lipid metabolism as well as energy demand systems. These results demonstrated the substantial impact of iprodione on zebrafish liver development and function. Furthermore, the application of astaxanthin (an antioxidant) and p53 morpholino partially mitigated the liver toxicity caused by iprodione. To summarize, iprodione induces apoptosis through the upregulation of p53 mediated by oxidative stress signals, leading to liver toxicity in zebrafish. Our study highlights that exposure to iprodione can result in hepatotoxicity in zebrafish, and it may potentially pose toxicity risks to other aquatic organisms and even humans.

AICAR attenuates postoperative abdominal adhesion formation by inhibiting oxidative stress and promoting mesothelial cell repair.

BACKGROUND: Postoperative abdominal adhesion is one of most common complications after abdominal operations. 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) is an adenosine 5'-monophosphate activated protein kinase (AMPK) pathway agonist that inhibits inflammation, reduces cell fibrosis and cellular reactive oxygen species (ROS) injury, promotes autophagy and mitochondrial function. This study aimed to explore the mechanism of AICAR in inhibiting adhesion formation. MATERIALS AND METHODS: Forty rats were randomly divided into five groups. All of the rats except the sham group received cecal abrasion to establish an adhesion model. The rats in the sodium hyaluronate group were treated with 2 mL sodium hyaluronate before closing the peritoneal cavity. The AICAR 1 and 2 groups were treated with 100 mg/kg and 200 mg/kg AICAR, respectively. Seven days after the operation, all of the rats were euthanized, and the adhesion condition was evaluated by Nair's system. Inflammation was assessed by Eosin-hematoxylin (HE) staining and transforming growth factor-ß (TGF-ß1) detection. Oxidative stress effect was determined by ROS, nitric oxide (NO) level, superoxide dismutase (SOD), catalase, glutathione peroxidase (Gpx) and malondialdehyde (MDA) levels in adhesion tissue. Then, Sirius red picric acid staining was used to detect the fiber thickness. Immunohistochemical staining of cytokeratin-19 (CK-19), alpha-smooth muscle actin (α-SMA) and nuclear factor erythroid 2-related factor 2 (Nrf2) was also performed. Finally, HMrSV5 cells were treated with TGF-ß1 and AICAR, the mRNA expression of E-cadherin, α-SMA and vimentin was assessed by q-PCR and cellular immunofluorescent staining. RESULTS: The rats in the AICAR-treated group had fewer adhesion formation incidences and a reduced Nair's score. The inflammation was determined by HE staining and TGF-ß1 concentration. The ROS, SOD, Catalase, Gpx, MDA levels and fiber thickness were decreased by AICAR treatments compared to the control. However, the NO production, Nrf2 levels and peritoneal mesothelial cell integrity were promoted after AICAR treatments. In vitro work, AICAR treatments reduced E-cadherin, α-SMA and vimentin mRNA level compared to that in the TGF-ß1 group. CONCLUSION: AICAR can inhibit postoperative adhesion formation by reducing inflammation, decreasing oxidative stress response and promoting peritoneal mesothelial cell repair.

Acadesine alleviates acute pancreatitis-related lung injury by mediating the barrier protective function of pulmonary microvascular endothelial cells.

Severe acute pancreatitis (SAP) is a condition characterized by highly fatal acute inflammation and is usually associated with multiple organ dysfunction syndrome. Acute lung injury (ALI) is the most common complications of SAP, which is the accelerator of other organ dysfunction caused by SAP and the primary cause of early death due to SAP. Acadesine, an adenosine analog and an AMPK activator, has been discovered to modulate glucose and lipid metabolism, and inhibit the production of pro-inflammatory cytokines and iNOS. However, its role in SAP-ALI and its mechanism remains unclear and need to be explored. Herein, we discovered that acadesine mitigated the generation of reactive oxygen species (ROS) in human pulmonary microvascular endothelial cells (HPMECs), alleviated apoptosis and recovered barrier integrity, thereby contributing to anti-inflammatory effects in vitro and in vivo. Moreover, Nrf2 deficiency partially eliminated the effects of acadesine-induced antioxidant effects and thus weakened the protective effects on cells and Nrf2-knockout (Nrf2-/-) mice. This study demonstrates that acadesine attenuated SAP-ALI associated inflammation and tissue damage by modulating the Nrf2-dependent antioxidant pathway by triggering AMPK. These findings are of great significance for the treatment of SAP-related lung injury.

Exposure to iprodione induces ROS production and mitochondrial dysfunction in porcine trophectoderm and uterine luminal epithelial cells, leading to implantation defects during early pregnancy.

Iprodione is a well-known fungicide used in the cultivation of strawberries, tomatoes, grapes, and green beans. In recent studies, neurotoxicity, cardiotoxicity, and endocrine toxicity of iprodione have been reported. Although reproductive toxicity of iprodione has been identified in animal studies, its effects are limited to male fertility. Also, the toxic effects of iprodione on pregnancy, especially the implantation process, have not been elucidated. This study demonstrated a series of cytotoxic responses of iprodione along with the alteration of implantation-related gene expression in porcine trophectoderm (pTr) and luminal epithelium (pLE) cells. In this study, iprodione suppressed cell viability, proliferation, and migration of these cells. Iprodione induced G1 phase arrest and attenuated spheroid formation by pTr and pLE cells. Furthermore, iprodione caused mitochondrial dysfunction and excessive reactive oxygen species generation, which resulted in an increase in mitochondrial calcium levels. Consequently, DNA damage and apoptotic cell death were induced by iprodione treatment in pTr and pLE cells. This stress-induced cell death was mediated by alterations in intracellular signal transduction, including the PI3K/AKT and MAPK signaling pathways. This finding suggests the potential of iprodione to impair the implantation capacity by exerting cytotoxic effects on fetal and maternal cells.

Case report of a rare purine synthesis disorder due to 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase (AICAR) deficiency.

BACKGROUND: AICA (5-aminoimidazole-4-carboxamide) ribosiduria is an inborn error in purine biosynthesis caused due to biallelic pathogenic variants in the 5-aminoimidazole-4-carboxamide ribonucleotide-formyltransferase/imp cyclohydrolase (ATIC) gene located on chromosome 2q35. ATIC codes for a bifunctional enzyme, AICAR transformylase and inosine monophosphate (IMP) cyclohydrolase, which catalyse the last two steps of de novo purine synthesis. This disorder has been previously reported in only 4 cases worldwide, and herein, we report the first from India. CASE REPORT: The proband presented with global developmental delay, developmental hip dysplasia (DDH), acyanotic heart disease and nystagmoid eye movements. Whole exome sequencing (WES) identified compound heterozygous pathogenic variants in the ATIC. A novel splice site variant; c.1321-2A > G and a previously reported missense variant; c.1277A > G (p.Lys426Arg) were identified. Segregation analysis of parents showed the father to be a heterozygous carrier for the splice site variant and the mother, a heterozygous carrier for the missense variant. CONCLUSION: This case of a rare genetic disorder of purine biosynthesis of ATIC deficiency is the first case reported from India. Early diagnosis lead to early interventional therapy and genetic counselling.

5-Amino-4-Imidazolecarboxamide Ribonucleotide Transformylase/IMP Cyclohydrolase Polymorphisms Affect the Susceptibility to Multiple Myeloma.

OBJECTIVE: The upregulation of 5-amino-4-imidazolecarboxamide ribonucleotide transformylase/IMP cyclohydrolase (ATIC) may affect tumorigenesis and multiple myeloma (MM) development. MATERIALS AND METHODS: A total of 97 patients with MM and 102 healthy control patients were included in the study. The SNaPshot technique was used to detect the ATIC gene polymorphisms. Linkage disequilibrium (LD) and haplotype analyses were conducted using SHEsis software. RESULTS: The genotype distribution or allele frequency of rs3772078 and rs16853834 was significantly different between the patients with MM and the healthy control patients (all P < .05). The rs16853834 A allele, rs3772078 CT genotype, and C allele were associated with a decreased risk of MM (all P < .05). Five single-nucleotide polymorphism combinations showed strong LD. Three haplotypes were associated with MM risk (all P < .05). We found that ATIC rs7604984 was significantly associated with serum lactate dehydrogenase levels (P = .050). CONCLUSION: We determined that the rs3772078 and rs16853834 polymorphisms are associated with a decreased risk of MM.

Anti-cancer Effects of 5-Aminoimidazole-4-Carboxamide-1-ß-D-Ribofuranoside (AICAR) on Triple-negative Breast Cancer (TNBC) Cells: Mitochondrial Modulation as an Underlying Mechanism.

BACKGROUND: Triple-negative breast cancer (TNBC) is known for Warburg effect and defects in the mitochondria. AMP-dependent kinase (AMPK) activates the downstream transcription factors PGC-1α, PGC-1ß, or FOXO1, which participate in mitochondrial biogenesis. 5- aminoimidazole-4-carboxamide riboside (AICAR) is an analog of adenosine monophosphate and is a direct activator of AMPK. OBJECTIVES: In the present study, we have made an attempt to understand the influence of AICAR on TNBC cells, MDA-MB-231, and the underlying changes in mitochondrial biogenesis, if any. METHODS: We investigated AICAR induced changes in cell viability, apoptosis, migratory potential, and changes in the sensitivity of doxorubicin. RESULTS: In response to the treatment of MDA-MB-231 breast cancer cells with 750 µM of AICAR for 72 hours, followed by 48 hours in fresh media without AICAR, we observed a decrease in viability via MTT assay, reduction in cell numbers along with the apoptotic appearance, increased cell death by ELISA, decreased lactate in conditioned medium and decrease in migration by scratch and transwell migration assays. These changes in the cancer phenotype were accompanied by an increase in mitochondrial biogenesis, as observed by increased mitochondrial DNA to nuclear DNA ratio, a decrease in lactic acid concentration, an increase in MitoTracker green and red staining, and increased expression of transcription factors PGC-1α, NRF-1, NRF-2, and TFAM, contributing to mitochondrial biogenesis. Pre-treatment of cells with AICAR for 72 hours followed by 48 hours treatment with 1 µM doxorubicin showed an increased sensitivity to doxorubicin as assessed by the MTT assay. CONCLUSION: Our results show that AICAR exerts beneficial effects on TNBC cells, possibly via switching off the Warburg effect and switching on the anti-Warburg effect through mitochondrial modulation.

Pathway-specific effects of ADSL deficiency on neurodevelopment.

Adenylosuccinate lyase (ADSL) functions in de novo purine synthesis (DNPS) and the purine nucleotide cycle. ADSL deficiency (ADSLD) causes numerous neurodevelopmental pathologies, including microcephaly and autism spectrum disorder. ADSLD patients have normal serum purine nucleotide levels but exhibit accumulation of dephosphorylated ADSL substrates, S-Ado, and SAICAr, the latter being implicated in neurotoxic effects through unknown mechanisms. We examined the phenotypic effects of ADSL depletion in human cells and their relation to phenotypic outcomes. Using specific interventions to compensate for reduced purine levels or modulate SAICAr accumulation, we found that diminished AMP levels resulted in increased DNA damage signaling and cell cycle delays, while primary ciliogenesis was impaired specifically by loss of ADSL or administration of SAICAr. ADSL-deficient chicken and zebrafish embryos displayed impaired neurogenesis and microcephaly. Neuroprogenitor attrition in zebrafish embryos was rescued by pharmacological inhibition of DNPS, but not increased nucleotide concentration. Zebrafish also displayed phenotypes commonly linked to ciliopathies. Our results suggest that both reduced purine levels and impaired DNPS contribute to neurodevelopmental pathology in ADSLD and that defective ciliogenesis may influence the ADSLD phenotypic spectrum.

The Fairy Chemical Imidazole-4-carboxamide Inhibits the Expression of Axl, PD-L1, and PD-L2 and Improves Response to Cisplatin in Melanoma.

The leading cause of death worldwide is cancer. Many reports have proved the beneficial effect of mushrooms in cancer. However, the precise mechanism is not completely clear. In the present study, we focused on the medicinal properties of biomolecules released by fairy ring-forming mushrooms. Fairy chemicals generally stimulate or inhibit the growth of surrounding vegetation. In the present study, we evaluated whether fairy chemicals (2-azahypoxanthine, 2-aza-8-oxohypoxanthine, and imidazole-4-carboxamide) exert anticancer activity by decreasing the expression of Axl and immune checkpoint molecules in melanoma cells. We used B16F10 melanoma cell lines and a melanoma xenograft model in the experiments. Treatment of melanoma xenograft with cisplatin combined with imidazole-4-carboxamide significantly decreased the tumor volume compared to untreated mice or mice treated cisplatin alone. In addition, mice treated with cisplatin and imidazole-4-carboxamide showed increased peritumoral infiltration of T cells compared to mice treated with cisplatin alone. In vitro studies showed that all fairy chemicals, including imidazole-4-carboxamide, inhibit the expression of immune checkpoint molecules and Axl compared to controls. Imidazole-4-carboxamide also significantly blocks the cisplatin-induced upregulation of PD-L1. These observations point to the fairy chemical imidazole-4-carboxamide as a promising coadjuvant therapy with cisplatin in patients with cancer.

AMP-activated protein kinase-dependent nuclear localization of glyceraldehyde 3-phosphate dehydrogenase in senescent human diploid fibroblasts.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key glycolytic enzyme that participates in various cellular events, such as DNA repair and apoptosis. The functional diversity of GAPDH depends on its intracellular localization. Because AMP-activated protein kinase (AMPK) regulates the nuclear translocation of GAPDH in young cells and AMPK activity significantly increases during aging, we investigated whether altered AMPK activity is involved in the nuclear localization of GAPDH in senescent cells. Age-dependent nuclear translocation of GAPDH was confirmed by confocal laser scanning microscopy in human diploid fibroblasts (HDFs) and by immunohistochemical analysis in aged rat skin cells. Senescence-induced nuclear localization was reversed by lysophosphatidic acid but not by platelet-derived growth factor. The extracellular matrix from young cells also induced the nuclear export of GAPDH in senescent HDFs. An activator of AMPK, 5-Aminoimidazole-4-carboxamide-1-ß-D-ribofuranoside (AICAR), increased the level of nuclear GAPDH, whereas an inhibitor of AMPK, Compound C, decreased the level of nuclear GAPDH in senescent HDFs. Transfection with AMPKα siRNA prevented nuclear translocation of GAPDH in senescent HDFs. The stimulatory effect of AICAR and serum depletion on GAPDH nuclear translocation was reduced in AMPKα1/α2-knockout mouse embryonic fibroblasts. Overall, increased AMPK activity may play a role in the senescence-associated nuclear translocation of GAPDH.

Wide distribution of resistance to the fungicides fludioxonil and iprodione in Penicillium species.

Fludioxonil and iprodione are effective fungicides widely used for crop protection and are essential for controlling plant pathogenic fungi. The emergence of fungicide-resistant strains of targeted pathogens is regularly monitored, and several cases have been reported. Non-targeted fungi may also be exposed to the fungicide residues in agricultural fields. However, there are no comprehensive reports on fungicide-resistant strains of non-targeted fungi. Here, we surveyed 99 strains, representing 12 Penicillium species, that were isolated from a variety of environments, including foods, dead bodies, and clinical samples. Among the Penicillium strains, including non-pathogenic P. chrysogenum and P. camembertii, as well as postharvest pathogens P. expansum and P. digitatum, 14 and 20 showed resistance to fludioxonil and iprodione, respectively, and 6 showed multi-drug resistance to the fungicides. Sequence analyses revealed that some strains of P. chrysogenum and Penicillium oxalicum had mutations in NikA, a group III histidine kinase of the high-osmolarity glycerol pathway, which is the mode of action for fludioxonil and iprodione. The single nucleotide polymorphisms of G693D and T1318P in P. chrysogenum and T960S in P. oxalicum were only present in the fludioxonil- or iprodione-resistant strains. These strains also exhibited resistance to pyrrolnitrin, which is the lead compound in fludioxonil and is naturally produced by some Pseudomonas species. This study demonstrated that non-targeted Penicillium strains distributed throughout the environment possess fungicide resistance.

Novel 4-phenoxypyridine derivatives bearing imidazole-4-carboxamide and 1,2,4-triazole-3-carboxamide moieties: Design, synthesis and biological evaluation as potent antitumor agents.

Two series of novel 4-phenoxypyridine derivatives containing imidazole-4-carboxamide and 4-methyl-5-oxo-4,5-dihydro-1,2,4-triazole-3-carboxamide moieties were synthesized and evaluated for their in vitro inhibitory activities against c-Met kinase and antiproliferative activities against MKN-45, A549 and H460 cancer cell lines. The results indicated that most of the compounds showed moderate to good antitumor activities. The most promising compound T14 (with c-Met IC50 value of 0.012 µM) showed remarkable antiproliferative activities against MKN-45, A549 and H460 cell lines with IC50 values of 0.64 µM, 1.92 µM and 2.68 µM, respectively. Their preliminary structure-activity relationships (SARs) studies indicate that imidazole-4-carboxamide was more preferred as linker part, and electron-withdrawing groups (especially halogen groups) on the terminal phenyl rings were beneficial for improving the antitumor activities.

AICAR stimulates mitochondrial biogenesis and BCAA catabolic enzyme expression in C2C12 myotubes.

Type 2 diabetes is characterized by reduced insulin sensitivity, elevated blood metabolites, and reduced mitochondrial metabolism. Insulin resistant populations often exhibit reduced expression of genes governing mitochondrial metabolism such as peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). Interestingly, PGC-1α regulates the expression of branched-chain amino acid (BCAA) metabolism, and thus, the consistently observed increased circulating levels of BCAA in diabetics may be partially explained by reduced PGC-1α expression. Conversely, PGC-1α upregulation appears to increase BCAA catabolism. PGC-1α activity is regulated by 5'-AMP-activated protein kinase (AMPK), however, only limited experimental data exists on the effect of AMPK activation in the regulation of BCAA catabolism. The present report examined the effects of the commonly used AMPK activator 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) on the metabolism and expression of several related targets (including BCAA catabolic enzymes) of cultured myotubes. C2C12 myotubes were treated with AICAR at 1 mM for up to 24 h. Mitochondrial and glycolytic metabolism were measured via oxygen consumption and extracellular acidification rate, respectively. Metabolic gene and protein expression were assessed via qRT-PCR and western blot, respectively. AICAR treatment significantly increased mitochondrial content and peak mitochondrial capacity. AICAR treatment also increased AMPK activation and mRNA expression of several regulators of mitochondrial biogenesis but reduced glycolytic metabolism and mRNA expression of several glycolytic enzymes. Interestingly, branched-chain alpha-keto acid dehydrogenase a (BCKDHa) protein was significantly increased following AICAR-treatment suggesting increased overall BCAA catabolic capacity in AICAR-treated cells. Together, these experiments demonstrate AICAR/AMPK activation can upregulate BCAA catabolic machinery in a model of skeletal muscle.

A Multi-enzyme Cascade for the Biosynthesis of AICA Ribonucleoside Di- and Triphosphate.

AICA (5'-aminoimidazole-4-carboxamide) ribonucleotides with different phosphorylation levels are the pharmaceutically active metabolites of AICA nucleoside-based drugs. The chemical synthesis of AICA ribonucleotides with defined phosphorylation is challenging and expensive. In this study, we describe two enzymatic cascades to synthesize AICA derivatives with defined phosphorylation levels from the corresponding nucleobase and the co-substrate phosphoribosyl pyrophosphate. The cascades are composed of an adenine phosphoribosyltransferase from Escherichia coli (EcAPT) and different polyphosphate kinases: polyphosphate kinase from Acinetobacter johnsonii (AjPPK), and polyphosphate kinase from Meiothermus ruber (MrPPK). The role of the EcAPT is to bind the nucleobase to the sugar moiety, while the kinases are responsible for further phosphorylation of the nucleotide to produce the desired phosphorylated AICA ribonucleotide. The selected enzymes were characterized, and conditions were established for two enzymatic cascades. The diphosphorylated AICA ribonucleotide derivative ZDP, synthesized from the cascade EcAPT/AjPPK, was produced with a conversion up to 91 %. The EcAPT/MrPPK cascade yielded ZTP with conversion up to 65 % with ZDP as a side product.

Synthesis and evaluation of 2-(4-[4-acetylpiperazine-1-carbonyl] phenyl)-1H-benzo[d]imidazole-4-carboxamide derivatives as potential PARP-1 inhibitors and preliminary study on structure-activity relationship.

Although 1H-benzo[d]imidazole-4-carboxamide derivatives have been explored for a long time, the structure-activity relationship of the substituents in the hydrophobic pocket (AD binding sites) has not thoroughly discovered. Here in, a series of 2-(4-[4-acetylpiperazine-1-carbonyl]phenyl)-1H-benzo[d]imidazole-4-carboxamide derivatives have been designed, synthesized, and successful characterization as novel and effective poly ADP-ribose polymerases (PARP)-1 inhibitors to improve the structure-activity relationships about the substituents in the hydrophobic pocket. These derivatives were evaluated for their PARP-1 inhibitory activity and cellular inhibitory against BRCA-1 deficient cells (MDA-MB-436) and wild cells (MCF-7) using PARP kit assay and MTT method. The results indicated that compared with other heterocyclic compounds, furan ring-substituted derivatives 14n-14q showed better PARP-1 inhibitory activity. Among this derivatives, compound 14p displayed the strongest inhibitory effects on PARP-1 enzyme (IC50  = 0.023 µM), which was close to that of Olaparib. 14p (IC50  = 43.56 ± 0.69 µM) and 14q (IC50  = 36.69 ± 0.83 µM) displayed good antiproliferation activity on MDA-MB-436 cells and inactivity on MCF-7 cells, indicating that 14p and 14q have high selectivity and targeting. The molecular docking method was used to explore the binding mode of compound 14p and PARP-1, and implied that the formation of hydrogen bond was essential for PARP-1 inhibition activities. This study also showed that in the hydrophobic pocket (AD binding sites), the introduction of strong electronegative groups (furan ring, e.g.) or halogen atoms in the side chain of benzimidazole might improve its inhibitory activity and this strategy could be applied in further research.

The inhibitory effect of AMP-activated protein kinase (AMPK) on chemokine and prostaglandin production in human endometrial stromal cells.

BACKGROUND: To investigate the role of adenosine monophosphate (AMP)-activated protein kinase (AMPK) on the production of interleukin (IL)-8, monocyte chemoattractant protein (MCP)-1, prostaglandin E2 and F2α induced by IL-1ß in endometrial stromal cells (ESCs) following treatment with 5-aminoimidazole-4- carboxamide ribonucleoside (AICAR). METHODS: Endometrial specimens were obtained and cultured. We examined the effects of IL-1ß, IL-1 ra and AICAR on the production of IL-8, MCP-1, PGE2 and PGF2α in human ESCs. The phosphorylations of AMPK, IκB, 4EBP-1, p70S6K and S6 ribosomal protein were analyzed by Western immunoblotting. RESULTS: Following stimulation by IL-1ß, the production of IL-8, MCP-1, PGE2 and PGF2α showed significant increases, and these increases were suppressed by AICAR. The expression of cyclooxygenase-2 (COX-2) induced by IL-1ß and suppressed by AICAR. The phosphorylation of IκB, 4EBP-1, p70S6K and S6 ribosomal protein were inhibited via an AMPK-dependent signal transduction. CONCLUSIONS: The production of IL-8, MCP-1, PGE2 and PGF2α induced by IL-1ß in ESCs were involved in the negative regulatory mechanisms of AMPK. The substances that activate AMPK may be promising agents for the treatment of pathological problems such as dysmenorrhea.

Medium & long-chain acylcarnitine's relation to lipid metabolism as potential predictors for diabetic cardiomyopathy: a metabolomic study.

BACKGROUND: Acylcarnitine is an intermediate product of fatty acid oxidation. It is reported to be closely associated with the occurrence of diabetic cardiomyopathy (DCM). However, the mechanism of acylcarnitine affecting myocardial disorders is yet to be explored. This current research explores the different chain lengths of acylcarnitines as biomarkers for the early diagnosis of DCM and the mechanism of acylcarnitines for the development of DCM in-vitro. METHODS: In a retrospective non-interventional study, 50 simple type 2 diabetes mellitus patients and 50 DCM patients were recruited. Plasma samples from both groups were analyzed by high throughput metabolomics and cluster heat map using mass spectrometry. Principal component analysis was used to compare the changes occurring in the studied 25 acylcarnitines. Multivariable binary logistic regression was used to analyze the odds ratio of each group for factors and the 95% confidence interval in DCM. Myristoylcarnitine (C14) exogenous intervention was given to H9c2 cells to verify the expression of lipid metabolism-related protein, inflammation-related protein expression, apoptosis-related protein expression, and cardiomyocyte hypertrophy and fibrosis-related protein expression. RESULTS: Factor 1 (C14, lauroylcarnitine, tetradecanoyldiacylcarnitine, 3-hydroxyl-tetradecanoylcarnitine, arachidic carnitine, octadecanoylcarnitine, 3-hydroxypalmitoleylcarnitine) and factor 4 (octanoylcarnitine, hexanoylcarnitine, decanoylcarnitine) were positively correlated with the risk of DCM. Exogenous C14 supplementation to cardiomyocytes led to increased lipid deposition in cardiomyocytes along with the obstacles in adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) signaling pathways and affecting fatty acid oxidation. This further caused myocardial lipotoxicity, ultimately leading to cardiomyocyte hypertrophy, fibrotic remodeling, and increased apoptosis. However, this effect was mitigated by the AMPK agonist acadesine. CONCLUSIONS: The increased plasma levels in medium and long-chain acylcarnitine extracted from factors 1 and 4 are closely related to the risk of DCM, indicating that these factors can be an important tool for DCM risk assessment. C14 supplementation associated lipid accumulation by inhibiting the AMPK/ACC/CPT1 signaling pathway, aggravated myocardial lipotoxicity, increased apoptosis apart from cardiomyocyte hypertrophy and fibrosis were alleviated by the acadesine.

AICAR enhances the cytotoxicity of PFKFB3 inhibitor in an AMPK signaling-independent manner in colorectal cancer cells.

Numerous studies have shown that 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoform 3 (PFKFB3), a pivotal enzyme in modulating glycolysis, plays vital roles in various physiological processes. PFKFB3 activity could be regulated by several factors, such as hypoxia and AMPK signaling; however, it could also function as upstream of AMPK signaling. Here, we showed that PFKFB3 inhibitor PFK-15 induced cell viability loss and apoptosis. Deprivation of PFKFB3 inhibited autophagy, while enhanced the ubiquitin-proteasome degradation pathway. Furthermore, PFK-15 reduced both the AMPK and AKT-mTORC1 signaling pathways, as the attenuated phosphorylation level of kinases themselves and their substrates. The addition of AICAR rescued the AMPK activity and autophagy, but enhanced PFK-15-induced cell viability loss. In fact, AICAR promoted the cytotoxicity of PFK-15 even in the AMPKα1/2-silenced cells, indicating AICAR might function in an AMPK-independent manner. Nevertheless, AICAR further reduced the AKT-mTORC1 activity down-regulated by PFK-15. Moreover, it failed to enhance PFK-15's cytotoxicity in the AKT1/2-silenced cells, indicating AKT-mTORC1 participated during these processes. Collectively, the presented data demonstrated that PFK-15 inhibited cell viability, AMPK, and AKT-mTORC1 signaling, and AICAR probably enhanced the cell viability loss aroused by PFK-15 in an AKT-dependent and AMPK-independent manner, thereby revealing a more intimate relationship among PFKFB3, AMPK, and AKT-mTORC1 signaling pathways.

AICAR upregulates ABCA1/ABCG1 expression in the retinal pigment epithelium and reduces Bruch's membrane lipid deposit in ApoE deficient mice.

The etiology of age-related macular degeneration (AMD) is diverse; however, recent evidence suggests that the lipid metabolism-cholesterol pathway might be associated with the pathophysiology of AMD. The ATP-binding cassette (ABC) transporters, ABCA1 and ABCG1, are essential for the formation of high-density lipoprotein (HDL) and the regulation of macrophage cholesterol efflux. The failure of retinal or retinal pigment epithelium (RPE) cholesterol efflux to remove excess intracellular lipids causes morphological and functional damage to the retina. In this study, we investigated whether treatment with 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an AMP-activated protein kinase (AMPK) activator, improves RPE cholesterol efflux and Bruch's membrane (BM) lipid deposits. The protein and mRNA levels of ABCA1 and ABCG1 in ARPE-19 cells and retinal and RPE/choroid tissue from apolipoprotein E-deficient (ApoE-/-) mice were evaluated after 24 weeks of AICAR treatment. The cholesterol efflux capacity of ARPE-19 cells and the cholesterol-accepting capacity of apoB-depleted serum from mice were measured. The thickness of the BM and the degree of lipid deposition were evaluated using electron microscopy. AICAR treatment increased the phosphorylation of AMPK and the protein and mRNA expression of ABCA1 and ABCG1 in vitro. It promoted cholesterol efflux from ARPE-19 cells and upregulated the protein and mRNA levels of ABCA1 and ABCG1 in the retina and RPE in vivo. ApoB-depleted serum from the AICAR-treated group showed enhanced cholesterol-accepting capacity. Long-term treatment with AICAR reduced BM thickening and lipid deposition in ApoE-/- mice. In conclusion, AICAR treatment increased the expression of lipid transporters in the retina and RPE in vivo, facilitated intracellular cholesterol efflux from the RPE in vitro, and improved the functionality of HDL to accept cholesterol effluxed from the cell, possibly via AMPK activation. Collectively, these effects might contribute to the improvement of early age-related pathologic changes in the BM. Pharmacological improvement of RPE cholesterol efflux via AMPK activation may be a potential treatment strategy for AMD.