The Role of Calcium in Differentiation of Human Adipose-Derived Stem Cells to Adipocytes

Differentiation process of mesenchymal stem cells (MSCs) into adipocyte is involved in obesity. Multiple factors such as Ca²⁺ play important roles in different stages of this process. Because of the complicated roles of Ca²⁺ in adipogenesis, the aim of present investigation was to study the influx and efflux of Ca²⁺ into and out of the cells during adipogenesis. Adipose-derived MSCs were used to differentiate into adipocytes. MSCs were exposed to 2.5 mM Ca²⁺ or 1.8 mM Ca²⁺ plus calcium ionophore, A23187, for 3 days. Lipid staining, triglycerides (TG) content, and glyceraldehyde phosphate dehydrogenase (GAPDH) activity were evaluated to confirm the efficiency of the differentiation. Gene expression of GLUT4, PPARγ2, RAR-α, and calreticulin, as well as the protein levels of GLUT4 and PPARγ2 were determined. Ca²⁺ and in particular Ca²⁺ plus A23187 significantly lowered the efficiency of differentiation accompanied by decrease in intracellular TG deposits, GAPDH activity and alleviation of gene, and protein levels of GLUT4 and PPARγ2. While calreticulin and RAR-α were remarkably upregulated in A23187 group. This study showed the inhibitory effects of calcium in adipogenesis. Additionally, it indicated the greater inhibitory effect of calreticulin and RAR-α in controlling adipogenesis by higher levels of calcium.     

Oritavancin exhibits dual mode of action to inhibit cell-wall biosynthesis in Staphylococcus aureus

Solid-state NMR measurements performed on intact whole cells of Staphylococcus aureus labeled selectively in vivo have established that des-N-methylleucyl oritavancin (which has antimicrobial activity) binds to the cell-wall peptidoglycan, even though removal of the terminal N-methylleucyl residue destroys the d-Ala-d-Ala binding pocket. By contrast, the des-N-methylleucyl form of vancomycin (which has no antimicrobial activity) does not bind to the cell wall. Solid-state NMR has also determined that oritavancin and vancomycin are comparable inhibitors of transglycosylation, but that oritavancin is a more potent inhibitor of transpeptidation. This combination of effects on cell-wall binding and biosynthesis is interpreted in terms of a recent proposal that oritavancin-like glycopeptides have two cell-wall binding sites: the well-known peptidoglycan d-Ala-d-Ala pentapeptide stem terminus and the pentaglycyl bridging segment. The resulting dual mode of action provides a structural framework for coordinated cell-wall assembly that accounts for the enhanced potency of oritavancin and oritavancin-like analogues against vancomycin-resistant organisms.     

Oncofetal antigen/immature laminin receptor protein in pregnancy and cancer

The 37-kDa immature laminin receptor protein (iLRP) is a speciesconserved, universal immunogenic protein that is expressed in all thus-far examined embryonic and early fetal cells of inbred and outbred rodents. It has also been identified in human concepti. It is altered through normal maturation processes to become a non-immunogenic 67-kDa dimeric mature laminin receptor protein (mLRP) in mid-to late gestation in the mammalian fetus. This antigen ceases to be expressed as an active autoimmunogen in the full-term fetus and in the normal differentiating tissues and organs of the neonate or adult organism, apparently due to dimerization, but it is re-expressed as an immunogenic monomer in tumor cells. In this review, we highlight the known mechanisms of immune responses with particular emphasis on the possible role of the 37-kDa oncofetal antigen/immature laminin receptor (OFA/iLRP) in both pregnancy and cancer.     

Curvature effect on hemodynamic conditions at the inner bend of the carotid siphon and its relation to aneurysm formation

Although high-impact hemodynamic forces are thought to lead to cerebral aneurysmal change, little is known about the aneurysm formation on the inner aspect of vascular bends such as the internal carotid artery (ICA) siphon where wall shear stress (WSS) is expected to be low. This study evaluates the effect of vessel curvature and hemodynamics on aneurysm formation along the inner carotid siphon. Catheter 3D-rotational angiographic volumes of 35 ICA (10 aneurysms, 25 controls) were evaluated in 3D for radius of curvature and peak curvature of the siphon bend, followed by univariate statistical analysis. Computational fluid dynamic (CFD) simulations were performed on patient-derived models after aneurysm removal and on synthetic variants of increasing curvature. Peak focal siphon curvature was significantly higher in aneurysm bearing ICAs (0.36±0.045 vs. 0.30±0.048 mm⁻¹, p=0.003), with no difference in global radius of curvature (p=0.36). In CFD simulations, increasing parametric curvature tightness (from 5 to 3 mm radius) resulted in dramatic increase of WSS and WSS gradient magnitude (WSSG) on the inner wall of the bend. In patient-derived data, the location of aneurysms coincided with regions of low WSS (<4 Pa) flanked by high WSS and WSSG peaks. WSS peaks correlated with the aneurysm neck. In contrast, control siphon bends displayed low, almost constant, WSS and WSSG profiles with little spatial variation. High bend curvature induces dynamically fluctuating high proximal WSS and WSSG followed by regions of flow stasis and recirculation, leading to local conditions known to induce destructive vessel wall remodeling and aneurysmal initiation.     

Delivery of cytoplasmic proteins to autophagosomes

Autophagy represents a signaling-dependent regulated process that allows the degradation of some cellular proteins in autophagosomes, and plays a critical role in the management of cellular homeostasis under various stress conditions. In recent years, selective degradation of cytoplasmic proteins during stress has attracted considerable scientific interest. Here we examined the ability of resveratrol to induce autophagy in a variety of human cancer cell lines. We found that resveratrol-induced autophagy is accompanied by colocalization of proline-, glutamic acid-, and leucine-rich protein-1 (PELP1) with the green fluorescent protein-microtubule-associated protein 1 light chain 3 (GFP-LC3) in autophagosomes. In addition, we found that hepatocyte growth factor-regulated tyrosine kinase substrate (HRS), a previously shown PELP1-interacting protein, is co-recruited to autophagosomes in the presence of resveratrol. Although autophagy has been assumed to be a bulk and non-selective degradation process, in recent years, evidence of selective degradation of cytosolic proteins and organelles by autophagy is mounting. These observations suggest that the interaction of the target protein(s) with the delivery protein or proteins such as HRS facilitates the transport of certain cytoplasmic proteins to autophagosomes for their selective degradation, and thus, could influence the cytoplasmic as well as nuclear functions of nuclear receptor coregulators. Since PELP1 and, perhaps, other nuclear receptor coregulators are widely dysregulated in human cancers, these findings highlight the significance of the autophagic selective degradation of PELP1 following resveratrol (or other phytoestrogens) treatment in developing future strategies to use resveratrol under cancer prevention and therapeutic settings.     

The use of otolith shape to determine stock structure of <Emphasis Type="Italic">Engraulis encrasicolus</Emphasis> along the Tunisian coast

Engraulis encrasicolus is of great economic importance in the Mediterranean. However, little is known about its stock structure. Otolith shape analysis has been successfully used for fish stock identification. In this study, the stock structure of anchovy caught off the open sea and the coastal area of the Gulf of Tunis, lagoon of Bizerte and Lake of Ichkeul were investigated using otolith shape. Otolith shape was determined by Fourier analysis and then compared among specimens sampled from different areas with forward stepwise canonical discriminant analysis. Significant differences in otolith shape between the open sea and inshore anchovy groups were detected. Otolith shape of anchovy collected in the Lake of Ichkeul was distinct from the other groups. This finding suggests a clear discreteness of the open sea and the continental groups. The data highlighted the potential for using otolith shape analysis for anchovy stock identification, as well as the role of oceanographic features in determining stock separation. These findings will have major implications for anchovy fisheries management in Tunisia. By using a precautionary approach and considering the three areas as separate stocks, fisheries management strategies should be adjusted to achieve optimum sustainable production from each stock and to avoid decreases in genetic variety.