Blocking ACAT-1 Activity for Tumor Therapy with Fluorescent Hyperstar Polymer-Encapsulated Avasimible.

Targeting the distinct cholesterol metabolism of tumor cells is proposed as a novel way to treat tumors. Blocking acyl-CoA cholesterol acyltransferase-1 (ACAT-1) by the inhibitor avasimible (Ava), which elevates intracellular free cholesterol levels, is shown to effectively induce apoptosis. However, Ava faces disadvantages of poor water solubility, a short half-life, and no capability for fluorescence detection, which have greatly limited its application. Herein, a fluorescent hyperstar polymer (FHSP) is developed to encapsulate Ava to improve its ability to inhibit HeLa cells and K562 cells. The results of this study show that the obtained Ava-FHSP micelles possess a high drug loading capacity of 22.7% and bright green fluorescence. Ava and Ava-FHSP are cytotoxic to both HeLa and K562 cells and cause reductions in cell size, nuclear lysis, and chromatin condensation and hindered proliferation of both cell types by causing S phase cell cycle arrest. Further mechanistic analysis indicates that Ava-FHSP reduces the protein and messenger RNA expression of ACAT-1 and significantly increases intracellular free cholesterol levels, which can increase endoplasmic reticulum stress and finally cause cell apoptosis. All these results suggest that this fluorescent hyperstar polymer represents a potential therapeutic tumor strategy by changing the cholesterol metabolism of tumor cells.

Grape seed proanthocyanidins suppressed macrophage foam cell formation by miRNA-9 via targeting ACAT1 in THP-1 cells.

Abnormal lipid metabolism in macrophages leads to atherosclerosis (AS). Excessive LDL cholesterol uptake by macrophages in the aortic endothelium leads to formation of foam cells. Previous studies suggested that proanthocyanidins effectively suppress this process, while the in-depth mechanism has not been elucidated. In mononuclear THP-1 cells, we found that the oligomeric fraction of proanthocyanidins was more effective in suppressing foam cell formation and 25 µg ml-1 for 48 h were the optimum conditions. Under these model conditions, we investigated gene expression and for the first time reported expression of regulatory microRNA (miRNA). It was found that the proanthocyanidins restrained macrophage foaming mainly by lowering the expression levels of cholesterol influx-related receptors CD36 and SR-A, and promoting the expression of cholesterol efflux-related receptor ABCA1. Further, it was latest revealed that proanthocyanidins could notably inhibit the expression of ACAT1, a key gene for intracellular cholesterol esterification. Further investigation was performed on the expression of regulatory miRNAs (miR-134 for CD36, miR-134, miR-155 for SR-A, miR-155, let-7g for LOX-1, miR-9 for ACAT1, miR-27a, miR-19b, miR-10b and miR-33a for ABCA1). The relative expression of miR-9, a miRNA targeting ACAT1, was decreased after the treatment of proanthocyanidins. It was most likely that proanthocyanidins suppressed the expression of ACAT1 via up-regulating the expression of miR-9, thus lessening the intracellular lipid accumulation and eventually inhibiting macrophage foam cell formation. This assumption was further verified by use of miR-9 mimic and its inhibitor.

Reverse cholesterol transport-related miRNAs and their regulation by natural functional compounds.

Cardiovascular disease (CVD) is the biggest killer globally and atherosclerosis (AS) is the major trigger to this pathology. Abnormal cholesterol homeostasis is the starting point of AS, especially the aggregation of macrophage foam cells in the intra-arterial subcutaneous region. Reverse cholesterol transport (RCT) can remove excess cholesterol from macrophages and transport it to the liver for excretion, making this process vital to alleviate AS. MicroRNAs (miRNAs) are small, noncoding RNAs that play critical roles in various diseases including AS, by regulating post-transcriptional gene expression. Many natural compounds can exert anti-atherosclerotic effects by regulating different miRNAs that are implicated in RCT. Hence, targeting these miRNAs using natural functional compounds may be a safe, novel, and promising strategy to prevent and treat AS. This review describes the miRNAs involved in RCT and the potential uses of natural compounds to target RCT-related miRNAs to modulate AS.

Anti-tumor potential of cell free culture supernatant of Lactobacillus rhamnosus strains isolated from human breast milk.

Lactobacilli rhamnosus has been characterized as a probiotic and plays an important role in human health by stimulating the supplement of nutrients, preventing the colonization of pathogens, and influencing the immune system. This study investigated the anticancer activity of the three Lactobacillus rhamnosus strains SHA111, SHA112, and SHA113 isolated from human breast milk. The cell-free supernatant of a liquid culture of the three strains showed excellent antioxidant activities against DPPH free radicals, superoxide anion radicals, and hydroxyl radicals; furthermore, significant anticancer activity was found on cervix cancer cells (HeLa) via cytotoxicity and induction of apoptosis. RT-qPCR and western blot analysis showed the induction of apoptosis was achieved via the up-regulation of BAD, BAX, Caspase3, Caspase8, Caspase9, and down-regulation of BCL-2 genes in HeLa cells. The results suggest that these strains have potential anticancer capability.

Conversion of DON to 3-epi-DON in vitro and toxicity reduction of DON in vivo by Lactobacillus rhamnosus.

Deoxynivalenol (DON) is a mycotoxin that contaminates grains and feed. Degradation and toxicity reduction of DON by probiotics benefit human and animal health. Lactobacillus rhamnosus is an FDA-approved probiotic that can be used in children. After screening seven L. rhamnosus strains isolated from human milk, SHA113 showed the highest DON degradation rate of 60% under the optimal conditions of 37 °C, pH 6.0, OD600 = 1.5, 5 mg L-1 DON, and 48 h. When dead and live SHA113 cells were used separately, only the live cells reduced the DON concentration and transformed it into 3-epi-DON. Mice feeding experiments showed that pretreatment with SHA113 for 48 h reduced the toxicity of DON to the immunological system and organs. Directly feeding SHA113 cells could also slightly reduce the DON toxicity. Both in vitro and in vivo experiments indicated that L. rhamnosus has potential to reduce DON toxicity.

Capability of iturin from Bacillus subtilis to inhibit Candida albicans in vitro and in vivo.

Candida albicans is a fungal pathogen that is difficult to cure clinically. The current clinic C. albicans-inhibiting drugs are very harmful to humans. This study revealed the potential of iturin fractions from Bacillus subtilis to inhibit C. albicans in free status (MIC = 32 µg/mL) and natural biofilm in vitro. The inhibition mechanism was identified as an apoptosis pathway via the decrease of mitochondrial membrane potential, the increase of the reactive oxygen species (ROS) accumulation, and the induction of nuclear condensation. For in vivo experiments, the C. albicans infection model was constructed via intraperitoneal injection of 1 × 108C. albicans cells into mice. One day after the infection, iturin was used to treat infected mice at different concentrations alone and in combination with amphotericin B (AmB) by intraperitoneal injection. The treatment with AmB alone could cause the death of infected mice, whereas treatment with 15 mg/kg iturin per day alone led to the survival of all infected mice throughout the study. After continuously treated for 6 days, all mice were sacrificed and analyzed. As results, the combination of 15 mg/kg iturin and AmB at a ratio of 2:1 had the most efficient effect to remove the fungal burden in the kidney and cure the infected mice by reversing the symptoms caused by C. albicans infection, such as the loss of body weight, change of immunology cells in blood and cytokines in serum, and damage of organ structure and functions. Overall, iturin had potential in the development of efficient and safe drugs to cure C. albicans infection.

Origination, change, and modulation of geriatric disease-related gut microbiota during life.

The age-related changes in the diversity and composition of the gut microbiota are well described in recent studies. These changes have been suggested to be influenced by age-associated weakening of the immune system and low-grade chronic inflammation, resulting in numerous age-associated pathological conditions. Gut microbiota homeostasis is important throughout the life of the host by providing vital functions to regulate various immunological functions and homeostasis. Based on published results, we summarize the relationship between the gut microbiota and aging-related diseases, especially Parkinson's disease, immunosenescence, rheumatoid arthritis, bone loss, and metabolic syndrome. The change in composition of the gut microbiota and gut ecosystem during life and its influence on the host immunologic and metabolic phenotype are also analyzed to determine factors that affect aging-related diseases. Approaches to maintain host health and prevent or cure geriatric diseases are also discussed.

Anticancer potential against cervix cancer (HeLa) cell line of probiotic Lactobacillus casei and Lactobacillus paracasei strains isolated from human breast milk.

Lactic acid bacteria have been categorized as probiotics and play a crucial role in human health by stimulating the supply of nutrients, shaping the immune system, and preventing the colonization of pathogenic microbes. This study investigated the mechanisms for the action of three potential probiotic Lactobacillus strains: Lactobacillus casei SR1, Lactobacillus casei SR2, and Lactobacillus paracasei SR4 isolated from human breast milk. These Lactobacillus strains were identified via 16S DNA sequencing and characterized via biochemical assays including acid resistance, bile resistance, antioxidant activity, and antibiotic susceptibility. The bioactivity of the cell-free culture supernatant (CFCS) secreted by these strains on the cervix cancer (HeLa) cell line was also evaluated via cytotoxicity assay and apoptosis analysis. The mechanism of anticancer activity was also investigated via RT-qPCR and western blotting. The results demonstrated that these newly isolated Lactobacillus strains from human milk displayed noticeable probiotic characteristics such as excellent antibiotic susceptibility, outstanding antioxidant activity, and promising resistance to low pH and high concentration of bile salts. The results of the conducted bioactivity assays verified that the CFCSs had acceptable anticancer effects on cervix cancer (HeLa) cells by upregulating the expression of apoptotic genes BAX, BAD, caspase3, caspase8, and caspase9 and by downregulating the expression of the BCl-2 gene. Overall, these results indicate that the Lactobacillus strains isolated from human breast milk could be considered as a topical medication with a potential therapeutic index due to their efficacy against cervix cancer cells.

Dietary compounds have potential in controlling atherosclerosis by modulating macrophage cholesterol metabolism and inflammation via miRNA.

Atherosclerosis (AS) is a typical example of a widespread fatal cardiovascular disease. Accumulation of cholesterol-laden macrophages in the artery wall forms the starting point of AS. Increased influx of oxidized low-density lipoprotein to macrophages and decreased efflux of free cholesterol out of macrophages constitute major factors promoting the development of AS. Inflammation further aggravates the development of AS along or via interaction with the cholesterol metabolism. Many microRNAs (miRNAs) are related to the regulation of macrophage in AS in aspects of cholesterol metabolism and inflammation signaling. Dietary compounds perform AS inhibitory effects via miRNAs in the cholesterol metabolism (miR-19b, miR-378, miR-10b, miR-33a, and miR-33b) and two miRNAs in the inflammation signaling (miR-155 and miR-146a). The targeted miRNAs in the cholesterol metabolism vary greatly among different food compounds; however, in inflammation signaling, most food compounds target miR-155. Many receptors are involved in macrophages via miRNAs, including ABCA1 and ABCG1 as major receptors in the cholesterol metabolism, while nuclear factor-κB (NF-κB) and Nrf2 signaling and PI3K/AKT signaling pathways are targeted during inflammation. This article reviews current literature to investigate possible AS therapy with dietary compounds via targeting miRNAs. Currently existing problems were also discussed to guide further studies.

Analysis of a piezoelectric power harvester with adjustable frequency by precise electric field method.

A power harvester with adjustable frequency, which consists of a hinged-hinged piezoelectric bimorph and a concentrated mass, is studied by the precise electric field method (PEFM), taking into account a distribution of the electric field over the thickness. Usually, using the equivalent electric field method (EEFM), the electric field is approximated as a constant value in the piezoelectric layer. Charge on the upper electrode (UEC) of the bimorph is often assumed as output charge. However, different output charge can be obtained by integrating on electric displacement over the electrode with different thickness coordinates. Therefore, an average charge (AC) on thickness is often assumed as the output value. This method is denoted EEFM AC. The flexural vibration of the bimorph is calculated by the three methods and their results are compared. Numerical results illustrate that EEFM UEC overestimates resonant frequency, output power, and efficiency. EEFM AC can accurately calculate the output power and efficiency, but underestimates resonant frequency. The performance of the harvester, which depends on concentrated mass weight, position, and circuit load, is analyzed using PEFM. The resonant frequency can be modulated 924 Hz by moving the concentrated mass along the bimorph. This feature suggests that the natural frequency of the harvester can be adjusted conveniently to adapt to frequency fluctuation of the ambient vibration.