Hyaluronic Acid Suppresses the Expression of Metalloproteinases in Osteoarthritic Cartilage Stimulated Simultaneously by Interleukin 1β and Mechanical Load

Purpose

In patients with osteoarthritis (OA), intraarticular injection of hyaluronic acid (HA) frequently results in reduced pain and improved function for prolonged periods of time, i.e. more than 6 months. However, the mechanisms underlying these effects are not fully understood. Our underlying hypothesis is that HA modifies the enzymatic breakdown of joint tissues.

Methods

To test this hypothesis, we examined osteochondral cylinders from 12 OA patients. In a bioreactor, these samples were stimulated by interleukin 1β (Il1ß) (2 ng/ml) plus mechanical load (2.0 Mpa at 0.5 Hz horizontal and 0.1 Hz vertical rotation), thus the experimental setup recapitulated both catabolic and anabolic clues of the OA joint.

Results

Upon addition of HA at either 1 or 3 mg/ml, we observed a significant suppression of expression of metalloproteinase (MMP)-13. A more detailed analysis based on the Kellgren and Lawrence (K&L) OA grade, showed a much greater degree of suppression of MMP-13 expression in grade IV as compared to grade II OA. In contrast to the observed MMP-13 suppression, treatment with HA resulted in a suppression of MMP-1 expression only at 1 mg/ml HA, while MMP-2 expression was not significantly affected by either HA concentration.

Conclusion

Together, these data suggest that under concurrent catabolic and anabolic stimulation, HA exhibits a pronounced suppressive effect on MMP-13. In the long-run these findings may benefit the development of treatment strategies aimed at blocking tissue degradation in OA patients.     

Are the Effects of Response Inhibition on Gambling Long-Lasting?

A recent study has shown that short-term training in response inhibition can make people more cautious for up to two hours when making decisions. However, the longevity of such training effects is unclear. In this study we tested whether training in the stop-signal paradigm reduces risky gambling when the training and gambling task are separated by 24 hours. Two independent experiments revealed that the aftereffects of stop-signal training are negligible after 24 hours. This was supported by Bayes factors that provided strong support for the null hypothesis. These findings indicate the need to better optimise the parameters of inhibition training to achieve clinical efficacy, potentially by strengthening automatic associations between specific stimuli and stopping.     

Effects of Watershed Land use on Nitrogen Concentrations and δ 15 Nitrogen in Groundwater

Eutrophication is a major agent of change affecting freshwater, estuarine, and marine systems. It is largely driven by transportation of nitrogen from natural and anthropogenic sources. Research is needed to quantify this nitrogen delivery and to link the delivery to specific land-derived sources. In this study we measured nitrogen concentrations and δ¹⁵N values in seepage water entering three freshwater ponds and six estuaries on Cape Cod, Massachusetts and assessed how they varied with different types of land use. Nitrate concentrations and δ¹⁵N values in groundwater reflected land use in developed and pristine watersheds. In particular, watersheds with larger populations delivered larger nitrate loads with higher δ¹⁵N values to receiving waters. The enriched δ¹⁵N values confirmed nitrogen loading model results identifying wastewater contributions from septic tanks as the major N source. Furthermore, it was apparent that N coastal sources had a relatively larger impact on the N loads and isotopic signatures than did inland N sources further upstream in the watersheds. This finding suggests that management priorities could focus on coastal sources as a first course of action. This would require management constraints on a much smaller population.     

The Response of Human Macrophages to β-Glucans Depends on the Inflammatory Milieu

Background

β-glucans are fungal cell wall components that bind to the C-type lectin-like receptor dectin-1. Polymorphisms of dectin-1 gene are associated with susceptibility to invasive fungal infection and medically refractory ulcerative colitis. The purpose of this study has been addressing the response of human macrophages to β-glucans under different conditions mimicking the composition of the inflammatory milieu in view of the wide plasticity and large range of phenotypical changes showed by these cells, and the relevant role of dectin-1 in several pathophysiological conditions.

Principal Findings

Serum-differentiated macrophages stimulated with β-glucans showed a low production of TNFα and IL-1β, a high production of IL-6 and IL-23, and a delayed induction of cyclooxygenase-2 and PGE₂ biosynthesis that resembled the responses elicited by crystals and those produced when phagosomal degradation of the phagocytic cargo increases ligand access to intracellular pattern recognition receptors. Priming with a low concentration of LPS produced a rapid induction of cyclooxygenase-2 and a synergistic release of PGE₂. When the differentiation of the macrophages was carried out in the presence of M-CSF, an increased expression of dectin-1 B isoform was observed. In addition, this treatment made the cells capable to release arachidonic acid in response to β-glucan.

Conclusions

These results indicate that the macrophage response to fungal β-glucans is strongly influenced by cytokines and microbial-derived factors that are usual components of the inflammatory milieu. These responses can be sorted into three main patterns i) an elementary response dependent on phagosomal processing of pathogen-associated molecular patterns and/or receptor-independent, direct membrane binding linked to the immunoreceptor tyrosine-based activation motif-bearing transmembrane adaptor DNAX-activating protein 12, ii) a response primed by TLR4-dependent signals, and iii) a response dependent on M-CSF and dectin-1 B isoform expression that mainly signals through the dectin-1 B/spleen tyrosine kinase/cytosolic phospholipase A₂ route.     

An Integrative Analysis of the Effects of Auxin on Jasmonic Acid Biosynthesis in Arabidopsis thaliana

Auxin and jasmonic acid （JA） are two plant phytohormones that both participate in the regulation of many developmental processes. Jasmonic acid also plays important roles in plant stress response reactions. Although extensive investigations have been undertaken to study the biological functions of auxin and JA, little attention has been paid to the cross-talk between their regulated pathways. In the few available reports examining the effects of auxin on the expression of JA or JA-responsive genes, both synergetic and antagonistic results have been found. To further investigate the relationship between auxin and JA, we adopted an integrative method that combines microarray expression data with pathway information to study the behavior of the JA biosynthesis pathway under auxin treatment. Our results showed an overall downregulation of genes involved in JA biosynthesis, providing the first report of a relationship between auxin and the JA synthesis pathway in Arabidopsis seedlings.     

Effects of Single Amino Acid Substitutions on Aggregation and Cytotoxicity Properties of Amyloid β Peptide

International Journal of Peptide Research and Therapeutics - Alzheimer’s disease is the main cause of dementia and the deposition of amyloid beta peptide (Aβ) in the brain is the key...     

Effects of Troponin T Cardiomyopathy Mutations on the Calcium Sensitivity of the Regulated Thin Filament and the Actomyosin Cross-Bridge Kinetics of Human β-Cardiac Myosin

Hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) lead to significant cardiovascular morbidity and mortality worldwide. Mutations in the genes encoding the sarcomere, the force-generating unit in the cardiomyocyte, cause familial forms of both HCM and DCM. This study examines two HCM-causing (I79N, E163K) and two DCM-causing (R141W, R173W) mutations in the troponin T subunit of the troponin complex using human β-cardiac myosin. Unlike earlier reports using various myosin constructs, we found that none of these mutations affect the maximal sliding velocities or maximal Ca²⁺-activated ADP release rates involving the thin filament human β-cardiac myosin complex. Changes in Ca²⁺ sensitivity using the human myosin isoform do, however, mimic changes seen previously with non-human myosin isoforms. Transient kinetic measurements show that these mutations alter the kinetics of Ca²⁺ induced conformational changes in the regulatory thin filament proteins. These changes in calcium sensitivity are independent of active, cycling human β-cardiac myosin.     

Acromegaly—The Effects of Various Steroid Hormones on the Insulin-Induced Growth Hormone Response

The availability of a sensitive assay for human growth hormone has made it possible to directly measure the effects of various agents purported to alter growth patterns. Acromegalic patients present a special problem both in early diagnosis and in therapy. Being able to measure growth hormone in these patients provides an accurate index of activity and a precise measure of therapeutic effectiveness.In an attempt to determine whether a pituitary block of growth hormone secretion is feasible in this condition, a study was made of the effects of estrogen, androgen and glucocorticoid administration on growth hormone response to a standard insulin tolerance test in a patient with active acromegaly. In the dosage schedules used in this study, it was not possible to suppress either basal growth hormone secretion or blunt its responsiveness to the normal physiologic stimulus of hypoglycemia.     

The Influence of Cosolvent on the Complexation of HP-β-cyclodextrins with Oleanolic Acid and Ursolic Acid

The present work was aimed at the influence of ethanol on the complex formation of hydroxypropyl-β-cyclodextrin (HP-β-CD) with oleanolic acid (OA) and ursolic acid (UA), two insoluble isomeric triterpenic acids. Phase solubility studies were carried out to evaluate the solubilizing power of HP-β-CD, in association with ethanol, toward OA and UA. A mathematical model was applied to explain and predict the solubility of OA and UA influenced by HP-β-CD and ethanol. The solid complexes were prepared by evaporating the filtrate of samples which was prepared in different complexing media. The solubility of OA is much higher than that of UA in all the tested aqueous solutions. The solubility of OA and UA can be increased over 900 and 200 times, respectively, by forming complex with HP-β-CD. Ethanol (0.5%, v/v) can help the formation of OA-HP-β-CD complex, but is harmful to the formation of UA-HP-β-CD complex. Increasing solubility in water can be achieved by adding ethanol into the complexing media, but the concentration of ethanol should be optimized. The ring E of the chemical compounds has a great influence on the complexing process.     

Mixture Effects of Estrogenic Pesticides at the Human Estrogen Receptor α and β

Consumers of fruits and vegetables are frequently exposed to small amounts of hormonally active pesticides, some of them sharing a common mode of action such as the activation of the human estrogen receptor α (hERα) or β (hERβ). Therefore, it is of particular importance to evaluate risks emanating from chemical mixtures, in which the individual pesticides are present at human-relevant concentrations, below their corresponding maximum residue levels. Binary and ternary iso-effective mixtures of estrogenic pesticides at effect concentrations eliciting a 1 or 10% effect in the presence or absence of 17β-estradiol were tested experimentally at the hERα in the yeast-based estrogen screen (YES) assay as well as in the human U2-OS cell-based ERα chemical-activated luciferase gene expression (ERα CALUX) assay and at the hERβ in the ERβ CALUX assay. The outcome was then compared to predictions calculated by means of concentration addition. In most cases, additive effects were observed with the tested combinations in all three test systems, an observation that supports the need to expand the risk assessment of pesticides and consider cumulative risk assessment. An additional testing of mixture effects at the hERβ showed that most test substances being active at the hERα could also elicit additive effects at the hERβ, but the hERβ was less sensitive. In conclusion, effects of the same ligands at the hERα and the hERβ could influence the estrogenic outcome under physiological conditions.     

Structural Effects of Methionine Oxidation on Isolated Subdomains of Human Fibrin D and αC Regions

Oxidation of key methionine residues on fibrin leads to altered fibrin polymerization producing severely altered fibrin gel structure and function. This is important because fibrinogen and its modification by oxidative stress have been implicated as key contributors to both pathological thrombotic and hemorrhagic diseases ranging from cardiovascular thrombosis to the acute coagulopathy of trauma. However, how oxidation leads to altered fibrin polymerization remains poorly understood at the molecular level. We have applied a powerful and novel well-tempered ensemble parallel tempering (PT-WTE) technique along with conventional molecular dynamics (MD) simulation to investigate the molecular-level consequences of selective methionine oxidation of fibrinogen. We offer new insights into molecular mechanisms of oxidation-induced changes in fibrin polymerization, while focusing on the D region knob ‘B’ and hole ‘b’ interaction and αC-domain interactions, both of which are hypothesized to contribute to the lateral aggregation mechanism of fibrin fibrils. Methionine oxidation did not alter the native state or the stability of a bound knob ‘B’ surrogate when interacting with hole ‘b’ in the D region. However, applying PT-WTE simulation to a human homology model of the bovine N-terminal subdomain fragment from the αC-domain revealed that methionine oxidation altered the conformation of the hairpin-linking region to favor open rather than closed hairpin structures. We attribute this alteration to the disruption of the hairpin-linking region''s conformation, with oxidation increasing the radius of gyration for this segment. This result is in agreement with experimental data demonstrating decreased fibrin protofibril lateral aggregation when methionine oxidation is present in the same αC-domain fragment. Therefore, single methionine oxidation within the αC-domain is a likely molecular mechanism.     

Effects of Dexmedetomidine and Oxycodone on Neurocognitive and Inflammatory Response After Tourniquet-Induced Ischemia–Reperfusion Injury

To evaluate the effects of dexmedetomidine (Dex) and oxycodone (Oxy) on neurocognitive and inflammatory response after tourniquet-induced ischemia–reperfusion (I/R) injury. C57/BL6 mice were used to construct the mouse model of tourniquet-induced I/R injury. Mice (n?=?48) were randomly divided into sham, I/R, Dex or Oxy group. Morris water maze test was performed to assess the spatial learning and memory function. The expression of NF-κB, TLR4, NR2B, M1 (CD68 and TNF-α) and M2 (CD206 and IL-10) polarization markers in mice hippocampus were detected by western blot or immunofluorescent staining. Spontaneous excitatory post-synaptic currents (sEPSCs) were recorded by electrophysiology. Dex treatment alleviated I/R-induced declines in learning and memory (p < 0.05), while Oxy had no significant effect on it. Compared with I/R group, Dex and Oxy treatment down-regulated the expression of NF-κB, TLR4, TNF-α and CD68 (all p < 0.05), while no significantly different was found in CD206 and IL-10. In addition, Dex treatment down-regulated the expression of NR2B and reduced the frequency and amplitude of sEPSCs in I/R model mice (all p < 0.05), while Oxy had no significant effect on them. Tourniquet-induced I/R could impair the neurocognitive function of mice. Dex treatment could alleviate I/R-induced neurocognitive disorder by inhibiting abnormal synaptic transmission in hippocampal neurons. Both Dex and Oxy could alleviate the inflammatory response likely by inhibiting the polarization of microglia toward M1 phenotype via TLR4/NF-κB pathway. Future studies are needed to further examine the effects of Dex on neurocognitive disorder after tourniquet-induced I/R injury and investigate the exact mechanism.

     

Effects of the Application of Different Concentrations of NaN3 for Different Times on the Morphological and Cytogenetic Characteristics of Barley （Hordeum vulgate L.） Seedlings

Sodium azide （NAN3） has been used in many biological studies as a mutagen. In the present study, the morphological and cytogenetic effects of NaN3 on barley （Hordeum vulgare L.） seedlings were investigated. Seeds of barley were treated with different concentrations of NaN3 （0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 mmol/L） and applied for different periods of time （3 and 4 h）. Parameters investigated, except for the mitotic index, were determined on Days 7 and 14. Increasing concentrations of NaN3 affected germination rates on Days 7 and 14 following application for 3 and 4 h. Although the length of the roots and leaves was affected by treatment with NaN3 on Day 14 of the germination period, coleoptile length was affected by NaN3 treatment on Day 7. Increasing concentrations of NaN3 and increased treatment period decreased the mitotic index compared with the untreated control. The inhibitory effects of NaN3 on the mitotic index indicate that NaN3 can have genotoxic and mutagenic effects on barley seedlings.     

Effects of Intracellular Calcium Chelation and Pifithrin-α on Deoxynucleotide Metabolism in Human Lymphocytes

Previously, we have found that activation of deoxycytidine kinase elicited by various DNA-damaging chemical agents could be prevented by BAPTA-AM, a cell-permeable calcium chelator or by pifithrin-α, a pharmacological inhibitor of p53. Here, we show that stimulation of deoxycytidine kinase by UV-light also is calcium-dependent and pifithrin-α-sensitive in tonsillar lymphocytes, while thymidine kinase 1 activity is stabilised in the presence of BAPTA-AM. Importantly, both UV-irradiation and calcium chelation decreased the incorporation of labelled deoxycytidine and thymidine into DNA. Pifithrin-alpha dramatically reduced the labelling of both the nucleotide and DNA fractions, possibly due to inhibition of transmembrane nucleoside transport.     

Effects of Exogenous Indole Butyric Acid and Callus Formation on the Anti-oxidant Activity, Total Phenolic, and Anthocyanin Constituents of Mulberry Cuttings

In order to evaluate the effects of exogenous indole butyric acid （IBA） and callus formation on the antioxidant activity, total phenolics, and anthocyanin constituents of Morus nigra L. and M. alba L. cuttings, we investigated the variations before and after the treatment. The results indicate that anti-oxidant ability, total phenolic, and anthocyanin constituents of the callus stems of both Morus species were higher than those of non-callus forming species. There were also increases observed in anti-oxidant ability, total phenolic, and anthocyanin constituents of calli treated with IBA （1 000-3 000 mg/L）.