Neuronal microRNAs safeguard ER Ca2+ homeostasis and attenuate the unfolded protein response upon stress.

Ca2+ is a critical mediator of neurotransmitter release, synaptic plasticity, and gene expression, but also excitotoxicity. Ca2+ signaling and homeostasis are coordinated by an intricate network of channels, pumps, and calcium-binding proteins, which must be rapidly regulated at all expression levels. Τhe role of neuronal miRNAs in regulating ryanodine receptors (RyRs) and inositol 1,4,5-triphosphate receptors (IP3Rs) was investigated to understand the underlying mechanisms that modulate ER Ca2+ release. RyRs and IP3Rs are critical in mounting and propagating cytosolic Ca2+ signals by functionally linking the ER Ca2+ content, while excessive ER Ca2+ release via these receptors is central to the pathophysiology of a wide range of neurological diseases. Herein, two brain-restricted microRNAs, miR-124-3p and miR-153-3p, were found to bind to RyR1-3 and IP3R3 3'UTRs, and suppress their expression at both the mRNA and protein level. Ca2+ imaging studies revealed that overexpression of these miRNAs reduced ER Ca2+ release upon RyR/IP3R activation, but had no effect on [Ca2+]i under resting conditions. Interestingly, treatments that cause excessive ER Ca2+ release decreased expression of these miRNAs and increased expression of their target ER Ca2+ channels, indicating interdependence of miRNAs, RyRs, and IP3Rs in Ca2+ homeostasis. Furthermore, by maintaining the ER Ca2+ content, miR-124 and miR-153 reduced cytosolic Ca2+ overload and preserved protein-folding capacity by attenuating PERK signaling. Overall, this study shows that miR-124-3p and miR-153-3p fine-tune ER Ca2+ homeostasis and alleviate ER stress responses.

A combination drug delivery system employing thermosensitive liposomes for enhanced cell penetration and improved in vitro efficacy.

Drug-loaded thermosensitive liposomes are investigated as drug delivery systems in combination with local mild hyperthermia therapy due to their capacity to release their cargo at a specific temperature range (40-42 °C). Additional benefit can be achieved by the development of such systems that combine two different anticancer drugs, have cell penetration properties and, when heated, release their drug payload in a controlled fashion. To this end, liposomes were developed incorporating at low concentration (5 mol%) a number of monoalkylether phosphatidylcholine lipids, encompassing the platelet activating factor, PAF, and its analogues that induce thermoresponsiveness and have anticancer biological activity. These thermoresponsive liposomes were efficiently (>90%) loaded with doxorubicin (DOX), and their thermal properties, stability and drug release were investigated both at 37 ◦C and at elevated temperatures. In vitro studies of the most advantageous liposomal formulation containing the methylated PAF derivative (methyl-PAF, edelfosine), an established antitumor agent, were performed on human prostate cancer cell lines. This system exhibits controlled release of DOX at 40-42 °C, enhanced cell uptake due to the presence of methyl-PAF, and improved cell viability inhibition due to the combined action of both medications.

Gold nanoparticle decorated pH-sensitive polymeric nanocontainers as a potential theranostic agent.

A pH-sensitive system of hollow P(MAA-co-MBA-co-AA) nanocontainers (NCs) modified with gold nanoparticles (GNCs) has been developed for theranostic applications, drug delivery and real time monitoring through imaging. The GNCs were synthesised by the distillation precipitation copolymerization procedure followed by in situ synthesis and embodiment of gold nanoparticles on the polymeric matrix (CSNs). Separately, citrate capped gold nanoparticles (GNPs) were also synthesized and compared with the GNCs for their fluorescence and cellular localization ability. The GNCs were tested for their drug loading and release behavior in response to the anticancer drug doxorubicin (DOX) at different pH values. Sustained drug release was observed at acidic pH. The viability of MCF-7 breast cancer cells and HEK-293 human embryonic kidney cells in relation to the GNCs, GNPs, GNC@DOX and DOX was also evaluated. GNCs and GNPs at the tested concentrations did not inhibit proliferation at either cell lines, whereas the GNCs@DOX presented comparable results. Cellular migration of MCF-7 cells treated with GNCs or GNPs was evaluated through the scratch-wound healing assay but no significant inhibition was detected. GNCs' and GNPs' fluorescence ability was exploited for assessing cellular localization through confocal laser scanning microscopy. GNCs after only 1 h of treatment were found in the cytoplasm of MCF7 cells, whereas GNCs@DOX were localized in the nucleus; the desirable site of action of DOX.

Should I stay or should I go? The settlement-inducing protein complex guides barnacle settlement decisions.

Reproduction in barnacles relies on chemical cues that guide their gregarious settlement. These cues have been pinned down to several sources of settlement pheromones, one of which is a protein termed settlement-inducing protein complex (SIPC), a large glycoprotein acting as a pheromone to induce larval settlement and as an adhesive in surface exploration by the cyprids. Settlement assays in laboratory conditions with Amphibalanus (=Balanus) amphitrite cyprids in the presence of SIPC showed that cyprids exhibit settlement preference behaviour at lower concentrations of SIPC [half maximal effective concentration (EC50)=3.73 nmol l-1] and settlement avoidance behaviour at higher concentrations (EC50=101 nmol l-1). By using truncated fragments of SIPC in settlement assays, we identify that domains at the N-terminus of SIPC transduce settlement preference cues that mask the settlement avoidance cues transduced by domains at its C-terminus. Removing the N-terminal 600 amino acids from SIPC resulted in truncated fragments that transduced only settlement avoidance cues to the cyprids. From the sexual reproduction point of view, this bimodal response of barnacles to SIPC suggests that barnacles will settle gregariously when conspecific cues are sparse but will not settle if conspecific cues inform of overcrowding that will increase reproductive competition and diminish their reproductive chances.

A Triphenylphosphonium-Functionalized Mitochondriotropic Nanocarrier for Efficient Co-Delivery of Doxorubicin and Chloroquine and Enhanced Antineoplastic Activity.

Drug delivery systems that target subcellular organelles and, in particular, mitochondria are considered to have great potential in treating disorders that are associated with mitochondrial dysfunction, including cancer or neurodegenerative diseases. To this end, a novel hyperbranched mitochondriotropic nanocarrier was developed for the efficient co-delivery of two different (both in chemical and pharmacological terms) bioactive compounds. The carrier is based on hyperbranched poly(ethyleneimine) functionalized with triphenylphosphonium groups that forms ~100 nm diameter nanoparticles in aqueous media and can encapsulate doxorubicin (DOX), a well-known anti-cancer drug, and chloroquine (CQ), a known chemosensitizer with arising potential in anticancer medication. The anticancer activity of this system against two aggressive DOX-resistant human prostate adenocarcinoma cell lines and in in vivo animal studies was assessed. The co-administration of encapsulated DOX and CQ leads to improved cell proliferation inhibition at extremely low DOX concentrations (0.25 µΜ). In vivo experiments against DU145 human prostate cancer cells grafted on immunodeficient mice resulted in tumor growth arrest during the three-week administration period and no pervasive side effects. The findings put forward the potential of such targeted low dose combination treatments as a therapeutic scheme with minimal adverse effects.

A fragment of the alarmin prothymosin α as a novel biomarker in murine models of bacteria-induced sepsis.

Sepsis is a life-threatening condition that requires urgent care. Thus, the identification of specific and sensitive biomarkers for its early diagnosis and management are of clinical importance. The alarmin prothymosin alpha (proTα) and its decapeptide proTα(100-109) are immunostimulatory peptides related to cell death. In this study, we generated bacterial models of sepsis in mice using two Klebsiella pneumoniae strains (L-78 and ATCC 43816) and monitored sepsis progression using proTα(100-109) as a biomarker. Serum concentration of proTα(100-109) gradually increased as sepsis progressed in mice infected with L-78, a strain which, unlike ATCC 43816, was phagocytosed by monocytes/macrophages. Analysis of splenocytes from L-78-infected animals revealed that post-infection spleen monocytes/macrophages were gradually driven to caspase-3-mediated apoptosis. These results were verified in vitro in L-78-infected human monocytes/macrophages. Efficient phagocytosis of L-78 by monocytes stimulated their apoptosis and the concentration of proTα(100-109) in culture supernatants increased. Human macrophages strongly phagocytosed L-78, but resisted cell death. This is the first report suggesting that high levels of proTα(100-109) correlate, both in vitro and in vivo, with increased percentages of cell apoptosis. Moreover, we showed that low levels of proTα(100-109) early post-infection likely correlate with sepsis resolution and thus, the decapeptide could eventually serve as an early surrogate biomarker for predicting bacteria-induced sepsis outcome.

Formation of an endoplasmic reticulum ring associated with acetylated microtubules in the angiosperm preprophase band.

We investigated the organization of the cortical endoplasmic reticulum (ER) in prophase cells of the angiosperms Zea mays, Triticum turgidum, and Vigna sinensis. In both symmetrically and asymmetrically dividing protodermal leaf cells, cortical ER was enriched in the preprophase band and colocalized there with microtubules, forming a ring-like structure (ER ring). In contrast, ER ring was absent from prophase root-tip cells of the same plants, suggesting that ER ring formation in the preprophase band is organ specific. Immunolabeling of the protodermal leaf cells revealed the presence of acetylated microtubules, which are more stable than the nonacetylated ones. In contrast, neither this post-translational modification of tubulin nor an accumulation of ER in the preprophase band was detected in root-tip cells. Experimentally delaying the maturation/disassembly of the microtubule ring of the preprophase band by taxol or cyclopiazonic acid treatment led to the appearance of ER ring and acetylated microtubules in the preprophase band. Together, our data show that in dividing cells of angiosperms, an ER ring associated with acetylated microtubules forms in the preprophase band.

Rare anatomic variation of left gastric artery and right hepatic artery in a female cadaver.

The present report describes a rare case in which the left gastric artery arises directly from the abdominal aorta and the right hepatic artery from the superior mesenteric artery, as observed during the dissection of a female cadaver. The left gastric artery usually rises as one of the three branches of the celiac trunk, which was originally described by Haller in 1756, whereas the right hepatic artery usually originates from the proper hepatic artery. The knowledge of the typical anatomy of the abdominal arteries, and their variations, is especially important due to the numerous interventions performed in the abdominal area.