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Extra-Virgin Olive Oil and Blood Pressure
Published in Catherina Caballero-George, Natural Products and Cardiovascular Health, 2018
Ana Belén Segarra, Magdalena Martínez-Cañamero, Germán Domínguez-Vías, Marina Hidalgo, Manuel Ramírez-Sánchez, Isabel Prieto
When mice fed diets with different degrees of dietary fatty acid saturation, serum total cholesterol levels are higher in mice fed diets containing saturated fat (lard and coconut) than in those fed diets with unsaturated fat (sunflower, fish and olive oil). Serum Aspartyl and Glutamyl Aminopeptidase activities are increased progressively also with the degree of saturation of the dietary fatty acids. Glutamyl and Aspartyl Aminopeptidases play a major role in the regulation of RAS. Glutamyl Aminopeptidase (Angiotensinase A) metabolizes Angiotensin II in Angiotensin III, and Aspartyl Aminopeptidase converts Angiotensin I in Angiotensin 2–10, which is further converted in Angiotensin III by the ACE enzyme. Therefore, the increase of serum Glutamyl and Aspartyl Aminopeptidase activities suggest a heightened metabolism of Ang I and II, which leads to an increase in Ang III levels (Arechaga et al., 2001).
Peptidases and Peptides at the Blood-Brain Barrier
Published in Gerard O’Cuinn, Metabolism of Brain Peptides, 2020
Janet Brownlees, Carvell Williams
This enzyme, also known as glutamyl aminopeptidase, will only cleave N-terminal acidic amino acids i.e. Asp or Glu. Bausback et al.127 showed the presence of a membrane bound aminopeptidase associated with the cerebral microvasculature of the pig that was immunologically indistinguishable from renal aminopeptidase A. Activity towards the synthetic fluorogenic substrate α–Glu-2-naphthylamide showed an enrichment of more than 12-fold over that in whole brain homogenate. The enzyme was shown to be sensitive to puromycin, amastatin and metalchelating agents and was found to hydrolyze α–glutamyl-2-naphthylamide five times faster than the corresponding α–aspartyl derivative, though it is not clear whether or not these data were obtained at saturating concentrations of substrate. A similar activity has recently been found in cerebral microvessels from the rat where it was enriched 23-fold, compared to total brain homogenate128 - see Table 2. An immunocytochemical study by Healy and Wilk129 using four antibodies raised to the purified rat kidney enzyme, revealed that aminopeptidase A in the rat brain is primarily associated with cerebral microvessels and, more precisely, to their abluminal surface. The staining suggested a localization in the perivascular pericytes. Staining was not exclusive to BBB microvessels, but was also found associated with vessels containing fenestrated endothelia and was most intense in the circumventricular organs, an area known to contain high levels of angiotensin II receptors. The BBB also contains such receptors, via which the peptide exerts effects on cerebral blood flow and permeability. The presence of aminopeptidase A on the abluminal side of the BBB suggests that one of its functions may be to metabolize peptides released from neurones. This raises the possibility that the enzyme may have a role in regulating the activity of angiotensins because both angiotensins I and II have Asp at position 1 and removal of this amino acid destroys biological activity.
Recent developments in pharmacotherapy for hypertriglyceridemia: what’s the current state of the art?
Published in Expert Opinion on Pharmacotherapy, 2020
Matilda Florentin, Michael S Kostapanos, Panagiotis Anagnostis, George Liamis
Pemafibrate is a newly developed fibrate, characterized by high potency and selectivity against PPARα, as a corollary of the addition of unique benzoxazole and phenoxyalkyl side-chains, which deliver a Y-shaped molecule [106,109]. This structure results in a PPARα conformation (after its binding with pemafibrate) which binds to PPARγ coactivator-1α (PGC-1α) and, finally, leads to complete activation of PPARα. This high selectivity of pemafibrate is interwoven with a > 2,500-fold higher potency than fenofibrate at a cellular level [106,109]. Except for its high affinity for VLDL and ABCA1 genes, pemafibrate also suppresses the activation of pro-inflammatory mediators in endothelial cells, such as vascular cell adhesion molecule 1 (VCAM-1) and monocyte chemoattractant protein-1 (MCP-1), whereas fenofibrate has no effect on them [110]. Its unique anti-inflammatory effect may be also due to the upregulation of mannose-binding lectin 2 (MBL2) gene [111]. Moreover, pemafibrate may upregulate genes implicated in blood pressure modulation [such as the glutamyl aminopeptidase (ENPEP) gene] [112] and glucose homeostasis [such as the fibroblast growth factor 21 (FGF21) gene] [113]. There is also evidence for a decreased expression of Niemann Pick C1-like 1 (NPC1L1) protein (small intestine), which further explains the beneficial effect of pemafibrate on atherogenic dyslipiaemia [114].
Discovery of differentially expressed genes in the intestines of Pelteobagrus vachellii within a light/dark cycle
Published in Chronobiology International, 2020
Chuanjie Qin, Jiaxian Sun, Jun Wang, Yongwang Han, He Yang, Qingchao Shi, Yunyun Lv, Peng Hu
Similar to mammals, the digestion and absorption of proteins in fish includes the hydrolysis of proteins and amino acid transport. In rats, Völkl and Poort (1983) indicated the existence of a clear-cut circadian rhythm in protein synthesis. Alkaline protease activity in the midgut of Nile tilapia (Oreochromis niloticus) showed a daily rhythm whose achrophase occurred at the beginning of the dark phase (Guerra-Santos et al. 2016). The present study showed that 34 DEGs were found within a light/dark cycle, which include genes encoding digestive enzymes, aminopeptidases, and amino acid transporters. The mRNA expression in ZT0 was higher than that at ZT6, ZT12, and ZT18, for genes encoding chymotrypsinogen 2, trypsin-3, chymotrypsin-C, puromycin-sensitive aminopeptidase, and glutamyl aminopeptidase. These enzymes are involved of the cleavage of lysine, arginine, tyrosine, tryptophan, phenylalanine, glutamate, aspartate, and methionine (Gregory and Dagmar 2004; Polgár 2005). The upregulated expression of these digestive enzymes in ZT0 might suggest that the maximum proteolysis of these amino acids occurs at night. Similarly, pancreatic protease activities (trypsinogen and chymotrypsinogen) in chicken showed a 24-hour cyclic rhythm (Rideau et al. 1983). The highest tryptic activities were found at 19:00, and the activities were lowest from 01:00 to 07:00 (Fujii et al. 2007). However, the expression of pepsin A mRNA was upregulated during the day. This enzyme efficiently in cleaves peptide bonds between hydrophobic amino acids, phenylalanine, tryptophan, and tyrosine. Similarly, a significant circadian rhythm was observed for pepsin efflux in the rat, with an acrophase value at 06:49 h after lights on, which continued during the lights-on resting phase (Barattini et al. 1993).