Pollen,diatom and plant macrofossil assemblages indicate a low water level phase of Lake Peipsi at the beginning of the Holocene

During the Fennoscandian ice recession from the eastern Baltic area, the water level in the Lake Peipsi basin was decreasing and reached a minimum at the end of the Younger Dryas Chronozone. The low lake level episode is represented in the basal deposits by a ca. 0.8 m thick bed of coarse detritus gyttja dated to 9.6–9.1 ka ¹⁴C BP. The gyttja lies at an elevation of 20–21 m a.s.l., i.e. about 9 m below the present lake level (30 m a.s.l.), and is buried under a 1.5–2 m bed of fine to medium-grained sand. The overall pollen data indicate a shallow-water littoral environment during the gyttja accumulation in the area studied. The diatom flora in the gyttja is dominated by shallow-water benthic and epiphytic taxa, indicating eutrophic littoral conditions at the time of gyttja accumulation. In the uppermost portion of the gyttja sequence the pollen and diatom successions indicate a short period of land emergence when swampy conditions prevailed in the surroundings.     

Identification of a Receptor for Neuropeptide VGF and Its Role in Neuropathic Pain

VGF (nonacronymic) is a neuropeptide precursor that plays multiple roles in regulation of energy balance, reproduction, hippocampal synaptic plasticity, and pain. Data from a number of pain models showed significant up-regulation of VGF in sensory neurons. TLQP-21, one of the VGF-derived neuropeptides, has been shown to induce a hyperalgesic response when injected subcutaneously into the hind paw of mice. However, the precise role of VGF-derived neuropeptides in neuropathic pain and the molecular identity of the receptor for VGF-derived peptides are yet to be investigated. Here we identified gC1qR, the globular heads of the C1q receptor, as the receptor for TLQP-21 using chemical cross-linking combined with mass spectrometry analysis. TLQP-21 caused an increase in intracellular Ca²⁺ levels in rat macrophages and microglia. Inoculation of TLQP-21-stimulated macrophages into rat hind paw caused mechanical hypersensitivity. The increase in intracellular Ca²⁺ levels in macrophages was attenuated by either siRNA or neutralizing antibodies against gC1qR. Furthermore, application of the gC1qR-neutralizing antibody to rats with partial sciatic nerve ligation resulted in a delayed onset of nerve injury-associated mechanical hypersensitivity. These results indicate that gC1qR is the receptor for TLQP-21 and plays an important role in chronic pain through activation of macrophages. Because direct association between TLQP-21 and gC1qR is required for activation of macrophages and causes hypersensitivity, disrupting this interaction may be a useful new approach to develop novel analgesics.     

Activation of transcription function in lymphocytes after irradiation with He-Ne-laser

The influence of He-Ne-laser irradiation (lambda = 632.8 nm) in dose 56 J/m2 on the ultrastructure of the nucleolus from human peripheral lymphocytes was studied electronmicroscopically. After 1 h irradiation a well-expressed reaction of the nucleolus was observed in 70% of the lymphocytes under examination. Changes consist in the appearance of a wrong-shaped fibrillar center or in its fragmentation, the increase of RNP-containing fibrillar and granular components, and also in expansion of vacuoli. In a number of irradiated lymphocytes nucleoli with several fibrillar centres and with a strand-like organization of RNP part were observed. The size of these nucleoli increases. Following the accepted functional interpretations the observed changes can be connected with the intensification of RNA metabolism including the synthesis, processing of pre-rRNA and preribosome transport from the nucleolus. Similar rearrangements of the nucleoli were revealed in parallel experiments with phytohemagglutinin-treated lymphocytes. They were observed 1 h after the stimulation of lymphocytes. Taking into account the absence of mitogenic action of He-Ne-laser irradiation on lymphocytes, the ultrastructural changes of nucleoli under the action of irradiation are considered as functional activation of rRNA synthesis in the Go-period.     

Novel anti-apoptotic effect of the retinoblastoma protein: implications for polyamine analogue toxicity

The retinoblastoma protein (pRb) pathway is frequently altered in breast cancer cells. pRb is involved in the regulation of cell proliferation and cell death. The breast cancer cell line L56Br-C1 does not express pRb and is extremely sensitive to treatment with the polyamine analogue N ¹,N ¹¹-diethylnorspermine (DENSPM) which causes apoptosis. Polyamines are essential for the regulation of cell proliferation, cell differentiation and cell death. DENSPM depletes cells of polyamines, e.g., by inducing the activity of the polyamine catabolic enzyme spermidine/spermine N ¹-acetyltransferase (SSAT). In this study, L56Br-C1 cells were transfected with human pRb–cDNA. Overexpression of pRb inhibited DENSPM-induced cell death and DENSPM-induced SSAT activity. This suggests that the pRb protein level is a promising marker for polyamine depletion sensitivity and that there is a connection between pRb and the regulation of SSAT activity. We also show that SSAT protein levels and SSAT activity do not always correlate, suggesting that there is an unknown regulation of SSAT.     

Blood flow dynamics of one cardiac cycle and relationship to mechanotransduction and trabeculation during heart looping

Analyses of form-function relationships during heart looping are directly related to technological advances. Recent advances in four-dimensional optical coherence tomography (OCT) permit observations of cardiac dynamics at high-speed acquisition rates and high resolution. Real-time observation of the avian stage 13 looping heart reveals that interactions between the endocardial and myocardial compartments are more complex than previously depicted. Here we applied four-dimensional OCT to elucidate the relationships of the endocardium, myocardium, and cardiac jelly compartments in a single cardiac cycle during looping. Six cardiac levels along the longitudinal heart tube were each analyzed at 15 time points from diastole to systole. Using image analyses, the organization of mechanotransducing molecules, fibronectin, tenascin C, α-tubulin, and nonmuscle myosin II was correlated with specific cardiac regions defined by OCT data. Optical coherence microscopy helped to visualize details of cardiac architectural development in the embryonic mouse heart. Throughout the cardiac cycle, the endocardium was consistently oriented between the midline of the ventral floor of the foregut and the outer curvature of the myocardial wall, with multiple endocardial folds allowing high-volume capacities during filling. The cardiac area fractional shortening is much higher than previously published. The in vivo profile captured by OCT revealed an interaction of the looping heart with the extra-embryonic splanchnopleural membrane providing outside-in information. In summary, the combined dynamic and imaging data show the developing structural capacity to accommodate increasing flow and the mechanotransducing networks that organize to effectively facilitate formation of the trabeculated four-chambered heart.     

Metabolic remodeling in human colorectal cancer and surrounding tissues: alterations in regulation of mitochondrial respiration and metabolic fluxes

The aim of the work was to evaluate whether or not there is glycolytic reprogramming in the neighboring cells of colorectal cancer (CRC). Using postoperative material we have compared the functional capacity of oxidative phosphorylation (OXPHOS) in CRC cells, their glycolytic activity and their inclination to aerobic glycolysis, with those of the surrounding and healthy colon tissue cells. Experiments showed that human CRC cannot be considered a hypoxic tumor, since the malignancy itself and cells surrounding it exhibited even higher rates of OXPHOS than healthy large intestine. The absence of acute hypoxia in colorectal carcinomas was also confirmed by their practically equal glucose-phosphorylating capacity as compared with surrounding non-tumorous tissue and by upregulation of VEGF family and their ligands. Studies indicated that human CRC cells in vivo exert a strong distant effect on the energy metabolism of neighboring cells, so that they acquire the bioenergetic parameters specific to the tumor itself. The growth of colorectal carcinomas was associated with potent downregulation of the creatine kinase system. As compared with healthy colon tissue, the tumor surrounding cells display upregulation of OXPHOS and have high values of basal and ADP activated respiration rates. Strong differences between the normal and CRC cells in the affinity of their mitochondria for ADP were revealed; the corresponding K_m values were measured as 93.6±7.7 µM for CRC cells and 84.9±9.9 µM for nearby tissue; both these apparent K_m (ADP) values were considerably (by almost 3 times) lower in comparison with healthy colon tissue cells (256±34 µM).     

Immunoglobulin G Fc N-glycan profiling in patients with gastric cancer by LC-ESI-MS: relation to tumor progression and survival

The IgG Fc glycans strongly influence the Fcγ receptor interactions and Fc-mediated effector mechanisms. Changes in the structure of IgG glycans are associated with various diseases, such as infections and autoimmunity. However, the possible role of Fc glycans in tumor immunity is not yet fully understood. The aim of this study was to profile the Fc N-glycans of IgG samples from patients with gastric cancer (n = 80) and controls (n = 51) using LC-ESI-MS method to correlate the findings with stage of cancer and patients survival. Analysis of 32 different IgG N-glycans revealed significant increase of agalactosylated (GnGnF, GnGn(bi)F), and decrease of galactosylated (AGn(bi), AGn(bi)F, AA(bi), AAF) and monosialylated IgG glycoforms (NaAF, NaA(bi)) in cancer patients. A statistically significant increase of Fc fucosylation was observed in tumor stage II and III whereas reverse changes were found for the presence of bisecting GlcNAc. Higher level of fully sialylated glycans and elevated expression of glycans with bisecting GlcNAc were associated with better survival rate. Our findings provide the first evidence that the changes in Fc glycan profile may predict the survival of patients with gastric cancer. Cancer stage-dependent changes in Fc fucosylation and the bisecting N-acteylglucosamine expression as well as an association of several IgG glycoforms with the survival suggest that IgG glycosylation is related to pathogenesis of cancer and progression of the disease.     

Induction of the Cytoprotective Enzyme Heme Oxygenase-1 by Statins Is Enhanced in Vascular Endothelium Exposed to Laminar Shear Stress and Impaired by Disturbed Flow

In addition to cholesterol-lowering properties, statins exhibit lipid-independent immunomodulatory, anti-inflammatory actions. However, high concentrations are typically required to induce these effects in vitro, raising questions concerning therapeutic relevance. We present evidence that endothelial cell sensitivity to statins depends upon shear stress. Using heme oxygenase-1 expression as a model, we demonstrate differential heme oxygenase-1 induction by atorvastatin in atheroresistant compared with atheroprone sites of the murine aorta. In vitro, exposure of human endothelial cells to laminar shear stress significantly reduced the statin concentration required to induce heme oxygenase-1 and protect against H₂O₂-mediated injury. Synergy was observed between laminar shear stress and atorvastatin, resulting in optimal expression of heme oxygenase-1 and resistance to oxidative stress, a response inhibited by heme oxygenase-1 small interfering RNA. Moreover, treatment of laminar shear stress-exposed endothelial cells resulted in a significant fall in intracellular cholesterol. Mechanistically, synergy required Akt phosphorylation, activation of Kruppel-like factor 2, NF-E2-related factor-2 (Nrf2), increased nitric-oxide synthase activity, and enhanced HO-1 mRNA stability. In contrast, heme oxygenase-1 induction by atorvastatin in endothelial cells exposed to oscillatory flow was markedly attenuated. We have identified a novel relationship between laminar shear stress and statins, demonstrating that atorvastatin-mediated heme oxygenase-1-dependent antioxidant effects are laminar shear stress-dependent, proving the principle that biomechanical signaling contributes significantly to endothelial responsiveness to pharmacological agents. Our findings suggest statin pleiotropy may be suboptimal at disturbed flow atherosusceptible sites, emphasizing the need for more specific therapeutic agents, such as those targeting Kruppel-like factor 2 or Nrf2.The efficacy of 3-hydroxy-3-methylglutaryl-coenzyme A reductase antagonists (statins) in reducing low density lipoprotein cholesterol, cardiovascular morbidity, and mortality is widely recognized (1). The observation that beneficial actions of statins on vascular function are detectable prior to any fall in serum cholesterol, extend to normocholesterolemic patients and exceed those of other lipid-lowering drugs despite comparable falls in total cholesterol (2, 3), suggest the existence of low density lipoprotein-cholesterol-independent effects (4, 5). Judging from in vitro studies, these may include immunomodulatory, anti-inflammatory, anti-adhesive, anti-thrombotic, and cytoprotective actions (6). However, the experimental work demonstrating these pleiotropic effects has predominantly used statin concentrations exceeding those achieved by therapeutic dosing, raising questions concerning clinical relevance (4).Heme oxygenase-1 (HO-1)² acts as the rate-limiting factor in the catabolism of heme into biliverdin, releasing free iron and carbon monoxide (CO). Biliverdin is subsequently converted to bilirubin by biliverdin reductase, whereas intracellular iron induces expression of heavy chain-ferritin and the opening of Fe²⁺ export channels (7). The biologic activity of HO-1 represents an important adaptive response in cellular homeostasis, as revealed by widespread inflammation and persistent endothelial injury in human HO-1 deficiency (8).Expression of HO-1 in atherosclerotic lesions, and its ability to inhibit vascular smooth muscle cell proliferation, exert anti-inflammatory, antioxidant, and antithrombotic effects, suggests a protective role during atherogenesis (9, 10). HMOX1 promoter polymorphisms affecting HO-1 expression may influence susceptibility to intimal hyperplasia and coronary artery disease, whereas a low serum bilirubin constitutes a cardiovascular risk factor (11). Moreover, overexpression of HO-1 inhibited atherogenesis, whereas Hmox1^−/− mice bred onto an ApoE^−/− background developed more extensive and complex atherosclerotic plaques (12, 13).Recent interest has focused on the therapeutic potential of HO-1 and its products, with probucol, statins, rapamycin, nitric oxide donors, and aspirin being shown to induce HO-1 (reviewed in Ref. 10). Indeed, induction of HO-1 may represent an important component of the vasculoprotective profile of statins, with simvastatin, atorvastatin, and rosuvastatin variously shown to increase HMOX1 promoter activity and mRNA levels, to induce enzyme activity and increase antioxidant capacity in human endothelial cells (EC) (14–18). However, induction of HO-1 in vascular EC in vivo has not yet been demonstrated.Vascular endothelium exposed to unidirectional, pulsatile laminar shear stress (LSS) >10 dynes/cm² is relatively protected against atherogenesis. LSS increases nitric oxide (NO) biosynthesis, prolongs EC survival, and generates an anticoagulant, anti-adhesive cell surface. In contrast, endothelium exposed to disturbed blood flow, with low shear reversing or oscillatory flow patterns, such as that located at arterial branch points and curvatures, is atheroprone. Thus endothelial cells exposed to disturbed blood flow exhibit reduced levels of endothelial nitric-oxide synthase (eNOS), increased apoptosis, oxidative stress, permeability to low density lipoprotein, and leukocyte adhesion (19).The atheroprotective influence of unidirectional LSS and the overlap between these actions and those of statins led us to hypothesize that LSS increases endothelial responsiveness to statins. We demonstrate for the first time that treatment of mice with atorvastatin induces HO-1 expression in the aortic endothelium and that this occurs preferentially at sites exposed to LSS. In vitro, pre-conditioning human EC with an atheroprotective, but not an atheroprone waveform, significantly reduces the concentration of atorvastatin required to enhance HO-1-mediated cytoprotection against oxidant-induced injury. A synergistic relationship between LSS and statins is revealed, resulting in maximal Akt phosphorylation and dependence upon eNOS, Kruppel-like factor 2 (KLF2), and NF-E2-related factor-2 (Nrf2) activation.