Identification of a novel Sp1 splice variant as a strong transcriptional activator.

The transcription factor Sp1 regulates expression of numerous genes involved in many cellular processes. Different post-transcriptional modifications can influence the transcriptional control activity and stability of Sp1. In addition to these modifications, alternative splicing isoforms may also be the basis of its distinct functional activities. In this study, we identified a novel alternative splice isoform of Sp1 named Sp1c. This variant is generated by exclusion of a short domain, which we designate a, through alternative splice acceptor site usage in the exon 3. The existence of this new isoform was confirmed in vivo by Western blotting analysis. Although at very low levels, Sp1c is ubiquitously expressed, as seen in its fulllength Sp1. A preliminary characterization of Sp1c shows that: (a) Sp1c works as stronger activator of transcription than full-length Sp1; (b) percentage of HEK293 Sp1c-overexpressing cells is higher in G1 phase and lower in S phase than percentage of HEK293 Sp1-overexpressing cells

Statins, fibrates and retinoic acid upregulate mitochondrial acylcarnitine carrier gene expression

In this study, we investigated the effects of statins, fibrates, 9-cis-retinoic acid and forskolin on the transcription of the mitochondrial carnitine/acylcarnitine carrier (CAC) gene. Statins, fibrates, retinoic acid and forskolin activate luciferase gene reporter activity driven by the -334/+3 bp region of the human CAC promoter containing wild-type (but not mutated) PPRE. These four agents also increase CAC transcript and protein levels. The combinations of statins and fibrates, retinoic acid and fibrates and fibrates and forskolin act synergistically. Mevalonate abolishes the activation of CAC gene expression by statins; the inhibitor of the PKA pathway H89 suppresses the stimulation of CAC gene expression by forskolin. Because CAC is essential for fatty acid beta-oxidation, the above results on the regulation of CAC gene expression provide a novel contribution to the understanding of the hypolipidemic action of statins, fibrates and retinoic acid

Statins, fibrates and retinoic acid upregulate mitochondrial acylcarnitine carrier gene expression

In this study, we investigated the effects of statins, fibrates, 9-cis-retinoic acid and forskolin on the transcription of the mitochondrial carnitine/acylcarnitine carrier (CAC) gene. Statins, fibrates, retinoic acid and forskolin activate luciferase gene reporter activity driven by the -334/+3 bp region of the human CAC promoter containing wild-type (but not mutated) PPRE. These four agents also increase CAC transcript and protein levels. The combinations of statins and fibrates, retinoic acid and fibrates and fibrates and forskolin act synergistically. Mevalonate abolishes the activation of CAC gene expression by statins; the inhibitor of the PKA pathway H89 suppresses the stimulation of CAC gene expression by forskolin. Because CAC is essential for fatty acid beta-oxidation, the above results on the regulation of CAC gene expression provide a novel contribution to the understanding of the hypolipidemic action of statins, fibrates and retinoic acid

Cancer cell metabolism in hypoxia: Role of HIF-1 as key regulator and therapeutic target

In order to meet the high energy demand, a metabolic reprogramming occurs in cancer cells. Its role is crucial in promoting tumor survival. Among the substrates in demand, oxygen is fundamental for bioenergetics. Nevertheless, tumor microenvironment is frequently characterized by low-oxygen conditions. Hypoxia-inducible factor 1 (HIF-1) is a pivotal modulator of the metabolic reprogramming which takes place in hypoxic cancer cells. In the hub of cellular bioenergetics, mitochondria are key players in regulating cellular energy. Therefore, a close crosstalk between mitochondria and HIF-1 underlies the metabolic and functional changes of cancer cells. Noteworthy, HIF-1 represents a promising target for novel cancer therapeutics. In this review, we summarize the molecular mechanisms underlying the interplay between HIF-1 and energetic metabolism, with a focus on mitochondria, of hypoxic cancer cells

Transcription of the mitochondrial citrate carrier gene: identification of a silencer and its binding protein ZNF224

In the last few years, we have been functionally characterizing the promoter of the human mitochondrial citrate carrier (CIC). In this study we show that CIC silencer activity extends over 26 bp (-595/-569), which specifically bind a protein present in HepG2 cell nuclear extracts. This transcription factor was purified by DNA affinity and identified as ZNF224. Overexpression of ZNF224 decreases LUC transgene activity in cells transfected with a construct containing the CIC silencer region, whereas ZNF224 silencing activates reporter transcription in cells transfected with the same construct. Moreover, overexpression and silencing of ZNF224 diminishes and enhances, respectively, CIC transcript and protein levels. Finally, ZNF224 is abundantly expressed in fetal tissues contrary to CIC. It is suggested that CIC transcriptional repression by ZNF224 explains, at least in part, the low expression of CIC in fetal tissues in which fatty acid synthesis is low

Ensemble consensus: An unsupervised algorithm for anomaly detection in network security data

Unsupervised network traffic monitoring is of paramount importance in cyber security. It allows to detect suspicious events that are defined as non-normal and report or block them. In this work the Anomaly Consensus algorithm for unsupervised network analysis is presented. The algorithm aim is to fuse the three most important anomaly detection techniques for unsupervised detection of suspicious events. Tests are performed against the KDD Cup'99 dataset, one of the most famous supervised datasets for automatic intrusion detection created by DARPA. Accuracies reveal that Anomaly Consensus performs on-par with respect to state-of-the-art supervised learning techniques, ensuring high generalization power also in borderline tests when small amount of data (5%) is used for training and the rest is for validation and testing

Liposome-mediated inhibition of inflammation by hydroxycitrate

Hydroxycitrate (HCA), a main organic acid component of the fruit rind of Garcinia cambogia, is a natural citrate analog that can inhibit the ATP citrate lyase (ACLY) enzyme with a consequent reduction of inflammatory mediators (i.e., nitric oxide (NO), reactive oxygen species (ROS), and prostaglandin E2 (PGE2)) levels. Therefore, HCA has been proposed as a novel means to prevent, treat, and ameliorate conditions involving inflammation. However, HCA presents a low membrane permeability, and a large quantity is required to have a biological effect. To overcome this problem, HCA was formulated in liposomes in this work, and the enhancement of HCA cell availability along with the reduction in the amount required to downregulate NO, ROS, and PGE2 in macrophages were assessed. The liposomes were small in size (~60 nm), monodispersed, negatively charged (−50 mV), and stable on storage. The in vitro results showed that the liposomal encapsulation increased by approximately 4 times the intracellular accumulation of HCA in macrophages, and reduced by 10 times the amount of HCA required to abolish LPS-induced NO, ROS, and PGE2 increase. This suggests that liposomal HCA can be exploited to target the citrate pathway involved in inflammatory processes

Immunometabolism Modulation by Extracts from Pistachio Stalks Formulated in Phospholipid Vesicles

Several studies have demonstrated the effectiveness of plant extracts against various diseases, especially skin disorders; namely, they exhibit overall protective effects. The Pistachio (Pistacia vera L.) is known for having bioactive compounds that can effectively contribute to a person’s healthy status. However, these benefits may be limited by the toxicity and low bioavailability often inherent in bioactive compounds. To overcome these problems, delivery systems, such as phospholipid vesicles, can be employed. In this study, an essential oil and a hydrolate were produced from P. vera stalks, which are usually discarded as waste. The extracts were characterized by liquid and gas chromatography coupled with mass spectrometry and formulated in phospholipid vesicles intended for skin application. Liposomes and transfersomes showed small size (<100 nm), negative charge (approximately −15 mV), and a longer storage stability for the latter. The entrapment efficiency was determined via the quantification of the major compounds identified in the extracts and was >80%. The immune-modulating activity of the extracts was assayed in macrophage cell cultures. Most interestingly, the formulation in transfersomes abolished the cytotoxicity of the essential oil while increasing its ability to inhibit inflammatory mediators via the immunometabolic citrate pathway

Mitochondria-mediated apoptosis of hcc cells triggered by knockdown of glutamate dehydrogenase 1: Perspective for its inhibition through quercetin and permethylated anigopreissin a

Metabolic reprogramming is a hallmark of cancer cells required to ensure high energy needs and the maintenance of redox balance. A relevant metabolic change of cancer cell bioenergetics is the increase in glutamine metabolism. Hepatocellular carcinoma (HCC), one of the most lethal cancer and which requires the continuous development of new therapeutic strategies, shows an up-regulation of human glutamate dehydrogenase 1 (hGDH1). GDH1 function may be relevant in cancer cells (or HCC) to drive the glutamine catabolism from L-glutamate towards the synthesis of α-ketoglutarate (α-KG), thus supplying key tricarboxylic acid cycle (TCA cycle) metabolites. Here, the effects of hGLUD1 gene silencing (siGLUD1) and GDH1 inhibition were evaluated. Our results demonstrate that siGLUD1 in HepG2 cells induces a significant reduction in cell proliferation (58.8% ± 10.63%), a decrease in BCL2 expression levels, mitochondrial mass (75% ± 5.89%), mitochondrial membrane potential (30% ± 7.06%), and a significant increase in mitochondrial superoxide anion (25% ± 6.55%) compared to control/untreated cells. The inhibition strategy leads us to identify two possible inhibitors of hGDH1: quercetin and Permethylated Anigopreissin A (PAA). These findings suggest that hGDH1 could be a potential candidate target to impair the metabolic reprogramming of HCC cells