Neuroprotective activity of macamides on manganese-induced mitochondrial disruption in U-87 MG glioblastoma cells.

Macamides are a distinct class of secondary metabolites, benzylamides of long chain fatty acids, which were isolated from the Peruvian plant Lepidium meyenii (Maca). As structural analogues of the endocannabinoid anandamide (AEA), they have demonstrated neuroprotective effects in vitro and in vivo. The purpose of this study was to demonstrate the neuroprotective activity of the macamides: N-(3-methoxybenzyl)oleamide (MAC 18:1), N-(3-methoxybenzyl)linoleamide (MAC 18:2) and N-(3-methoxybenzyl)linolenamide (MAC 18:3) in a neurotoxic environment caused by exposure of U-87 MG glioblastoma cells to manganese chloride (MnCl2). The neuroprotective effects of these macamides were reversed by the CB1 antagonist AM251. The mechanism by which manganese (Mn) induces cell damage was investigated by studying its effects on mitochondria. Reactive oxygen species (ROS) increase intracellular calcium and enhance the opening of mitochondrial permeability transition pores (MPTP), which leads to decreased mitochondrial membrane potential (MMP), to disruption of mitochondria and to neuron death in neurodegenerative disorders. In this study, MnCl2 at 50µM was responsible for mitochondrial disruption, which was attenuated by all three of the macamides tested. Human peroxisome proliferator-activated receptor gamma (PPARγ) has been proposed to be a cannabinoid target, and PPARγ has also been demonstrated to mediate some of the longer-term vascular effects of the plant cannabinoid, ∆9-tetrahydrocannabinol. PPARγ activation was observed in response to exposures of cells to MAC 18:2 and MAC 18:3. These findings suggest that macamides achieve their neuroprotective effects by binding to CB1 receptors to protect against Mn-induced toxicity in U-87 MG glioblastoma cells. Additionally these macamides, in a manner similar to the analogous endocannabinoid AEA, interact with other targets such as PPARγ to regulate metabolism and energy homeostasis, cell differentiation and inflammation.

Macamides and their synthetic analogs: evaluation of in vitro FAAH inhibition.

Maca (Lepidium meyenii), a traditional food crop of the Peruvian Andes is now widely touted as a dietary supplement. Among the various chemical constituents isolated from the plant are a unique series of non-polar, long-chain fatty acid N-benzylamides known as macamides. We have synthesized 11 of the 19 reported macamides and have tested each as potential inhibitors of the human enzyme, fatty acid amide hydrolase (FAAH). The five most potent macamides were FAAH inhibitors (IC50=10-17µM). These amides were derivatives of oleic, linoleic and linolenic acids and benzylamine or 3-methoxybenzylamine. Of the three compounds evaluated in a pre-incubation time study, two macamides were not irreversible inhibitors of FAAH. The third, a carbamate structurally related to macamides, was shown to be an irreversible inhibitor of FAAH (IC50=0.153µM).

Cytotoxic Activity of Saponins and Sapogenins Isolated from Chenopodium quinoa Willd. in Cancer Cell Lines.

The cytotoxic properties of two extracts from Chenopodium quinoa Willd. and three synthetic sapogenins were evaluated in different cancer cell lines (A549, SH-SY5Y, HepG2, and HeLa) to investigate their cytotoxic effects and determine if these cell lines activate the caspase pathway for apoptosis in response to saponin and sapogenin treatment. The saponin extracts were isolated from the agro-industrial waste of Chenopodium quinoa Willd., while the sapogenins were identified and quantitatively determined by High-Performance Liquid Chromatography (HPLC). Among these compounds, ursolic acid was the most active compound, with high IC50 values measured in all cell lines. In addition, hederagenin demonstrated higher caspase-3 activity than staurosporine in HeLa cells, suggesting an anti-cytotoxic activity via a caspase-dependent apoptosis pathway. HPLC analysis showed that the concentration of hederagenin was higher than that of oleanolic acid in ethanolic extracts of white and red quinoa. The ethanolic extracts of white and red quinoa did not show cytotoxic activity. On the other hand, the synthetic sapogenins such as ursolic acid, oleanolic acid, and hederagenin significantly decreased the viability of the four cell lines studied. Finally, by Caspase-3 assay, it was found that HeLa undergoes apoptosis during cell death because hederagenin produces a significant increase in PARP-1 hydrolysis in HeLa cells.

Diagnosis of Alzheimer's Disease in Developed and Developing Countries: Systematic Review and Meta-Analysis of Diagnostic Test Accuracy.

BACKGROUND: The present systematic review and meta-analysis of diagnostic test accuracy summarizes the last three decades in advances on diagnosis of Alzheimer's disease (AD) in developed and developing countries. OBJECTIVE: To determine the accuracy of biomarkers in diagnostic tools in AD, for example, cerebrospinal fluid, positron emission tomography (PET), and magnetic resonance imaging (MRI), etc. METHODS: The authors searched PubMed for published studies from 1990 to April 2020 on AD diagnostic biomarkers. 84 published studies were pooled and analyzed in this meta-analysis and diagnostic accuracy was compared by summary receiver operating characteristic statistics. RESULTS: Overall, 84 studies met the criteria and were included in a meta-analysis. For EEG, the sensitivity ranged from 67 to 98%, with a median of 80%, 95% CI [75, 91], tau-PET diagnosis sensitivity ranged from 76 to 97%, with a median of 94%, 95% CI [76, 97]; and MRI sensitivity ranged from 41 to 99%, with a median of 84%, 95% CI [81, 87]. Our results showed that tau-PET diagnosis had higher performance as compared to other diagnostic methods in this meta-analysis. CONCLUSION: Our findings showed an important discrepancy in diagnostic data for AD between developed and developing countries, which can impact global prevalence estimation and management of AD. Also, our analysis found a better performance for the tau-PET diagnostic over other methods to diagnose AD patients, but the expense of tau-PET scan seems to be the limiting factor in the diagnosis of AD in developing countries such as those found in Asia, Africa, and Latin America.

Effects of Annona muricata Extract on Triple-Negative Breast Cancer Cells Mediated Through EGFR Signaling.

PURPOSE: To evaluate the antiproliferative activity and the mechanisms of action of Annona muricata ethyl acetate (AMEA) extract and one of its active fractions on BT-20 TNBC cells. METHODS: The triple-negative human breast cancer BT-20 cells were used. After the preparation and extraction of Annona muricata ethyl acetate (AMEA), the ethyl acetate extract was exposed to a preparative thin layer chromatography (TLC) plate. From this preparative TLC plate, eight individual bands were collected. Each band was scraped and removed from the plate and soaked in ethyl acetate. After filtration, all eight fractions were then tested on the BT-20 TNBC cells using the MTS cell viability assay. The expressions of EGFR, p-EGFR, AKT, p-AKT, MAPK, p-MAPK, cyclin D1, and NF-κB p65 were measured using Western blot analysis. RESULTS: The AMEA showed a significant decrease in NF-κB p65 protein expression and BT-20 cell viability, as determined via the MTS assay. Furthermore, the AMEA was subjected to preparative thin layer chromatography (TLC), and eight fractions were obtained. From the eight fractions, only fraction 4 (F4) showed a significant reduction in cell viability in the MTS assay. Immunoblotting analysis revealed that AMEA and F4 formed an antiproliferative effect. These effects were complemented by a downregulation of cyclin D1 assembly, causing cell-cycle arrest at the G1/S phase. Furthermore, NF-κB was measured because of its involvement in the progression of cancers. CONCLUSION: The antiproliferative influence is produced through EGFR-mediated signaling pathways, which include AKT, MAPK, NF-κB, and cyclin D1 inhibition. Further studies will be required to demonstrate the possible applications of this natural product in breast cancer therapy.

Inhibition of PAR-1 Receptor Signaling by Enoxaparin Reduces Cell Proliferation and Migration in A549 Cells.

BACKGROUND/AIM: Low-molecular weight heparins (LMWHs) may possess putative antitumoral properties; however, the underlying mechanism(s) remains elusive. We evaluated the antiproliferative and antimigratory effects of enoxaparin (a LMWH) in lung adenocarcinoma A549 cells, and assessed the possible mechanism involved, and the effect on doxorubicin's efficacy. MATERIALS AND METHODS: Proliferation and migration were evaluated using BrdU and transwell assays, respectively. Immunoblotting was used to measure PAR-1, PAR-2, MMP-2, ERK1/2 and Akt proteins. Apoptosis and cell cycle studies examined the combined effect of enoxaparin and doxorubicin. RESULTS: Enoxaparin inhibited A549 cell proliferation and migration. Following PAR-1 gene knock down, enoxaparin's effect on A549 cell proliferation was diminished compared to scrambled siRNA. Our experiments verified that enoxaparin-mediated down-regulation of MAPK and PI3K, reduced MMP-2 expression and inhibited A549 cell migration. Additionally, enoxaparin increased doxorubicin's efficacy by enhancing apoptosis, while no effect on cell-cycle progression was observed. CONCLUSION: Results suggest that the anticancer activity of enoxaparin in A549 cells was mediated by the interference of two major PAR-1 downstream signaling pathways, MAPK/ERK and PI3K/Akt, which in turn inhibit proliferation and migration. Therefore, enoxaparin may be promising as an adjunct to traditional chemotherapy for lung cancer and warrants further investigation.

Influence of iron metabolism on manganese transport and toxicity.

Although manganese (Mn) is critical for the proper functioning of various metabolic enzymes and cofactors, excess Mn in the brain causes neurotoxicity. While the exact transport mechanism of Mn has not been fully understood, several importers and exporters for Mn have been identified over the past decade. In addition to Mn-specific transporters, it has been demonstrated that iron transporters can mediate Mn transport in the brain and peripheral tissues. However, while the expression of iron transporters is regulated by body iron stores, whether or not disorders of iron metabolism modify Mn homeostasis has not been systematically discussed. The present review will provide an update on the role of altered iron status in the transport and toxicity of Mn.

High Concentrations of Rosiglitazone Reduce mRNA and Protein Levels of LRP1 in HepG2 Cells.

Low-density lipoprotein receptor-related protein 1 (LRP1) is an endocytic receptor involved in the uptake of a variety of molecules, such as apoE, α2-macroglobulin, and the amyloid ß peptide (Aß), for either transcellular transport, protein trafficking or lysosomal degradation. The LRP1 gene can be transcribed upon activation of peroxisome proliferator receptor activated-γ (PPARγ) by the potent PPARγ agonist, rosiglitazone (RGZ). In previous studies, RGZ was shown to upregulate LRP1 levels in concentrations between 0.1 and 5 µM in HepG2 cells. In this study, we sought to replicate previous studies and to investigate the molecular mechanism by which high concentrations of RGZ reduce LRP1 levels in HepG2 cells. Our data confirmed that transcriptional activation of LRP1 occurred in response to RGZ at 3 and 10 µM, in agreement with the study reported by Moon et al. (2012a). On the other hand, we found that high concentrations of RGZ decreased both mRNA and protein levels of LRP1. Mechanistically, transcriptional dysregulation of LRP1 was affected by the downregulation of PPARγ in a time- and concentration-dependent manner. However, downregulation of PPARγ was responsible for only 40% of the LRP1 reduction and thereby the remaining loss of LRP1 (60%) was found to be through degradation in the lysosomal system. In conclusion, our findings demonstrate the mechanisms by which high concentrations of RGZ caused LRP1 levels to be reduced in HepG2 cells. Taken together, this data will be helpful to better explain the pharmacological modulation of this pivotal membrane receptor by PPARγ agonists.

The macamide N-3-methoxybenzyl-linoleamide is a time-dependent fatty acid amide hydrolase (FAAH) inhibitor.

The Peruvian plant Lepidium meyenii (Maca) has been shown to possess neuroprotective activity both in vitro and in vivo. Previous studies have also demonstrated the activity of the pentane extract and its macamides, the most representative lipophilic constituents of Maca, in the endocannabinoid system as fatty acid amide hydrolase (FAAH) inhibitors. One of the most active macamides, N-3-methoxybenzyl-linoleamide, was studied to determine its mechanism of interaction with FAAH and whether it has inhibitory activity on mono-acyl glycerol lipase (MAGL), the second enzyme responsible for endocannabinoid degradation. Macamide concentrations from 1 to 100 µM were tested using FAAH and MAGL inhibitor assay methods and showed no effect on MAGL. Tests with other conditions were performed in order to characterize the inhibitory mechanism of FAAH inhibition. N-3-methoxybenzyl-linoleamide displayed significant time-dependent and dose-dependent FAAH inhibitory activity. The mechanism of inhibition was most likely irreversible or slowly reversible. These results suggest the potential application of macamides isolated from Maca as FAAH inhibitors, as they might act on the central nervous system to provide analgesic, anti-inflammatory, or neuroprotective effects, by modulating the release of neurotransmitters.

Neuroprotective effects of Lepidium meyenii (Maca).

The neuroprotective activity of the plant Lepidium meyenii (Maca) was studied in two experimental models: in vitro and in vivo. Crayfish neurons were pretreated with vehicle or the pentane extract from Maca, subjected to H(2)O(2), and their viability determined microscopically and chemically. A significant concentration-neuroprotective effect relationship was demonstrated. The pentane extract was then administered intravenously to rats prior to and following middle cerebral artery occlusion. While infarct volumes were decreased for the lower dose, higher doses increased infarct volumes compared to controls. These results suggest a potential application of Maca as a neuroprotectant.