The effect of caraway oil-loaded bio-nanoemulsions on the growth and performance of barnyard grass and maize

A proper formulation is crucial to improve the herbicidal effects of essential oils and their selectivity. In this study, we investigated the physicochemical properties of bio-based nanoemulsions (CNs) containing several concentrations of caraway (Carum carvi) essential oil stabilized with Eco Tween 80, as a surfactant, maintaining 1:1 proportions. Detailed physicochemical characteristics of the CNs revealed that their properties were most desired at 2% of the oil and surfactant, i.e., the smallest droplet size, polydispersity index, and viscosity. The CNs caused biochemical changes in maize and barnyard grass (Echinochloa crus-galli) seedlings, however, to a different extent. Barnyard grass has overall metabolism (measured as a thermal power) decreased by 39-82% when exposed to the CNs. The CNs triggered changes in the content and composition of carbohydrates in the endosperm of both species' seedlings in a dose-response manner. The foliar application of CNs caused significant damage to tissues of young maize and barnyard grass plants. The effective dose of the CN (ED50, causing a 50% damage) was 5% and 17.5% oil in CN for barnyard grass and maize tissues, respectively. Spraying CNs also decreased relative water content in leaves and affected the efficiency of photosynthesis by disturbing the electron transport chain. We found that barnyard grass was significantly more susceptible to the foliar application of CNs than maize, which could be used to selectively control this species in maize crops. However, further studies are needed to verify this hypothesis under field conditions.

Strategies for the Management of Aggressive Invasive Plant Species

Current control methods for invasive alien plants (IAPs) have acceptable short-term outcomes but have proven to be unfeasible or unaffordable in the long-term or for large invaded areas. For these reasons, there is an urgent need to develop sustainable approaches to control or restrict the spread of aggressive IAPs. The use of waste derived from IAP control actions could contribute to motivating the long-term management and preservation of local biodiversity while promoting some economic returns for stakeholders. However, this strategy may raise some concerns that should be carefully addressed before its implementation. In this article, we summarize the most common methods to control IAPs, explaining their viability and limitations. We also compile the potential applications of IAP residues and discuss the risks and opportunities associated with this strategy.

Total Synthesis of the Proposed Structure of (-)-Novofumigatamide, Isomers Thereof, and Analogues. Part I

The total synthesis of the suggested structure of (−)-novofumigatamide, a natural product containing a C3-reverse prenylated N-acetyl-exo-hexahydropyrrolo[2,3-b]indole motif fused to a 10-membered ring lactam, was achieved using the macrolactam formation in advance of a diastereoselective bromocyclization and reverse prenylation steps. Since the NMR data of the synthetic sample did not match those of the natural product, the endo-bromo precursor of a N-Boc analogue and additional diastereomers derived from l-Trp were also synthesized. Five alternative synthetic routes, which differed in the order of final key steps used for the construction of the 10-membered ring lactam and the hexahydropyrrolo[2,3-b]indole framework within the polycyclic skeleton and also in the amide bond selected for the ring-closing of the macrolactam, were thoroughly explored. Much to our dismay, the lack of spectroscopic correlations between the proposed structure of natural (−)-novofumigatamide and the synthetic products suggested a different connectivity between the atoms. Additional synthetic efforts to assemble alternative structures of the natural product and isomers thereof (see accompanying paper; DOI: 10.1021/acs.joc.2c01228) further highlighted the frustrating endeavors toward the identification of a natural product.

Effect of plant origin and phenological stage on the allelopathic activity of the invasive species Oxalis pes-caprae

PREMISE

Invasion processes involve several mechanisms, some of which have received little attention. Allelopathy has been invoked as an invasion driver according to the novel weapon hypothesis (NWH), and polyploidization can also be an important factor for invasion success. However, very few studies have addressed both topics together. We analyzed the allelopathic effect of the polyploid Oxalis pes-caprae, an invader in mediterranean-climate areas worldwide, from different origins and ploidy levels (native: South Africa; invaded: Chile, Australia, California, and the Mediterranean Basin) on Lactuca sativa as a model species.

METHODS

We measured seed germination, initial plant height, and aboveground and belowground biomass of Lactuca grown in field soil mixed with Oxalis material and with or without activated carbon in a common garden experiment. We performed the experiment twice, when Oxalis was vigorous and when senescent.

RESULTS

Vigorous plants of Oxalis tended to reduce Lactuca germination, but both vigorous and senescent Oxalis plants increased Lactuca biomass, probably due to an increase in nutrients provided by plant material. The highest increase in Lactuca traits occurred with Oxalis plants from the Iberian Peninsula. Allelopathy only happened when Oxalis was senescent and was especially strong with plants from Chile.

CONCLUSIONS

Although we did not find broad evidence for the NWH considering all areas together, we reported differences in the allelopathic potential of Oxalis plants depending on their origin. These results highlight the independent evolution of invasiveness traits in distant introduced ranges and the importance of the invaders' origin when testing hypotheses about invasion drivers.

Influence of Acacia dealbata Link bark extracts on the growth of Allium cepa L. plants under high salinity conditions

BACKGROUND

Acacia dealbata Link is an invasive plant worldwide. Finding potential uses for its waste that contribute to controling its spread and result in benefits for agriculture has recently become a new topic of research. This study aimed to evaluate the potential biostimulant effect of bark extract derived from the management of A. dealbata (0, 450 or 900 ppm) on onion plants growing under stressful conditions, such as in soils treated with saline solutions (0, 60 or 120 mmol L^-1 NaCl) and with reduced irrigation (100%, 50% or 25%).

RESULTS

A. dealbata Link bark extract significantly increased height as well as leaf, root and total biomass of plants in soils irrigated with NaCl solution (120 mmol L^-1 ). These plants also had a higher content of Cl in roots, but a lower content of P in leaves and of K in bulbs. The 450 ppm bark treatment additionally increased the protein content in leaves and decreased the Na and Mg content in bulbs and bulbs and roots, respectively. The bark extract also increased the sugar content in plants under saline conditions. However, the effect of bark extract was negligible on plants that grew under drought stress.

CONCLUSION

Results revealed that the bark extract might attenuate stress effects in plants growing at high salinity levels, probably by increasing their sugar and protein content and via the accumulation of ions in the roots. Although additional experiments are required, we suggest that the bark extract of A. dealbata has potential applications in agriculture concerned with biostimulant formulations. © 2019 Society of Chemical Industry.

Stereospecific Allylic Functionalization: The Reactions of Allylboronate Complexes with Electrophiles

Allylboronic esters react readily with carbonyls and imines (π-electrophiles), but are unreactive toward a range of other electrophiles. By addition of an aryllithium, the corresponding allylboronate complexes display enhanced nucleophilicity, enabling addition to a range of electrophiles (tropylium, benzodithiolylium, activated pyridines, Eschenmoser's salt, Togni's reagent, Selectfluor, diisopropyl azodicarboxylate (DIAD), MeSX) in high regio- and stereocontrol. This protocol provides access to key new functionalities, including quaternary stereogenic centers bearing moieties such as fluorine and the trifluoromethyl group. The allylboronate complexes were determined to be 7 to 10 orders of magnitude more reactive than the parent boronic ester.

Quantification of cartilage oligomeric matrix protein (COMP) and a COMP neoepitope in synovial fluid of patients with different joint disorders by novel automated assays

OBJECTIVE

To develop automated immunoassays for the quantification of Cartilage Oligomeric Matrix Protein (COMP) and a COMP neoepitope in synovial fluid and to investigate their diagnostic potential in different joint conditions.

METHODS

Two sandwich immunoassays were developed for the quantification of COMP and a COMP neoepitope, using an automated analyser (IDS-iSYS, Immunodiagnostic Systems, Boldon, UK). Assay performance was evaluated in terms of sensitivity, recovery, linearity, and intra- and inter-assay precision. Clinical performance was evaluated by analysing synovial fluid from patients diagnosed with rheumatoid arthritis (RA), reactive arthritis (ReA), osteoarthritis (OA) or acute trauma (AT).

RESULTS

Both automated assays showed good performance for all parameters tested. Quantification of these biomarkers showed the highest median values for Total COMP in the OA group, followed by the AT group, the ReA group, and the RA group. For the COMP neoepitope the AT group showed the highest median value, followed by the ReA group, the OA group, and the RA group. The ratio COMP neoepitope/Total COMP showed distinct differences between the patients groups, as well as between RA patients with slow or rapid progression of joint damage.

CONCLUSIONS

The newly developed automated assays have a good technical performance, can reliably quantify different epitopes on the COMP molecule and show different levels of the two biomarkers in synovial fluid in patients with different joint diseases. The combination of these two assays, measuring their ratio, shows promise for early detection of patients with RA with different prognosis regarding progression of joint damage.

Total synthesis and structural revision of (+)-cristatumin C

Naturally occurring (+)-cristatumin C, a bis-pyrrolidinoindoline diketopiperazine alkaloid isolated from Eurotium cristatum EN-220, is the 2R,3R,11S,15R,2'R,3'R,11'S,15'S enantiomer, as confirmed by total synthesis.

Adamantyl arotinoids that inhibit IκB kinase α and IκB kinase β

A series of analogues of the adamantyl arotinoid (AdAr) chalcone MX781 with halogenated benzyloxy substituents at C2' and heterocyclic derivatives replacing the chalcone group were found to inhibit IκBα kinase α (IKKα) and IκBα kinase β (IKKβ) activities. The growth inhibitory capacity of some analogues against Jurkat T cells as well as prostate carcinoma (PC-3) and chronic myelogenous leukemia (K562) cells, which contain elevated basal IKK activity, correlates with the induction of apoptosis and increased inhibition of recombinant IKKα and IKKβ in vitro, pointing toward inhibition of IKK/NFκB signaling as the most likely target of the anticancer activities of these AdArs. While the chalcone functional group present in many dietary compounds has been shown to mediate interactions with IKKβ via Michael addition with cysteine residues, AdArs containing a five-membered heterocyclic ring (isoxazoles and pyrazoles) in place of the chalcone of the parent system are potent inhibitors of IKKs as well, which suggests that other mechanisms for inhibition exist that do not depend on the presence of a reactive α,β-unsaturated ketone.

[Gorlin syndrome (nevoid basal cell carcinoma syndrome)]

CLINICAL CASE

A 77 year-old male patient with Parkinson's disease and senile dementia had many facial basal cell carcinomas and an ectropion of the left eye. When he experienced respiratory difficulty he was diagnosed to have an ameloblastoma in left nostril requiring surgery.

DISCUSSION

Gorlin syndrome is an autosomal dominant condition characterized by basal cell carcinomas, and skeletal and neurological anomalies. The presence of multiple basal cell carcinomas on the eyelids in a child or in a young patient should alert ophthalmologists to the possibility of this syndrome.

The role of tumor necrosis factor-alpha in stress-induced worsening of cerebral ischemia in rats

Whereas stress is known to be one of the risk factors of stroke, few experimental studies have examined the possible mechanisms by which stress may affect stroke outcome. Most of the knowledge on the effects of stress on cerebrovascular disease in humans is restricted to catecholamines and glucocorticoids effects on blood pressure and/or development of atherosclerosis. By using an experimental paradigm consisting of the exposure of Fischer rats to repeated immobilization sessions (1 h daily during seven consecutive days) prior to permanent middle cerebral artery occlusion (MCAO), we have found that stress worsens behavioral outcome and increases infarct size after MCAO. These changes occur concomitantly to an increase in inducible nitric oxide synthase (iNOS) expression and to the accumulation of lipid peroxidation markers in brain tissue. The possible regulatory role of TNFalpha was studied by looking at the mechanisms of release of this cytokine as well as to the expression of its receptors (TNFR1 and 2). The results of the present study suggest an increase in TNFalpha expression and release after stress, as well as an increase in the expression of TNFR1. Pharmacological blockade of TNFalpha with anti-TNFalpha led to a decrease in the infarct size as well as in the oxidative/nitrosative biochemical parameters seen after ischemia. In summary, our results indicate that TNFalpha accounts, at least partly, for the worsening of MCAO consequences in brain of rats exposed to stress. Furthermore, the data presented here provide evidence that stress can increase brain ischemic damage and support a possible protective effect of treatment of stressful situations before and during the development of the brain ischemia.

Targets of cytoprotection in acute ischemic stroke: present and future

Although the management of stroke has improved remarkably over the last decade due mainly to the advent of thrombolysis, most neuroprotective agents, although successful in animal studies, have failed in humans. Our increasing knowledge concerning the ischemic cascade is leading to a considerable development of pharmacological tools suggesting that each step of this cascade might be a target for cytoprotection. Glutamate has long been recognized to play key roles in the pathophysiology of ischemia. However, although some trials are still ongoing, the results from several completed trials with drugs interfering with the glutamatergic pathway have been disappointing. Regarding the inhibition of glutamate release as a possible target for cytoprotection, it might be afforded either by decreasing glutamate efflux or by increasing glutamate uptake. In this context, it has been shown that glutamate transport is the primary and only mechanism for maintaining extracellular glutamate concentrations below excitotoxic levels. This transport is executed by the five high-affinity, sodium-dependent plasma membrane glutamate transporters. Among them, the transporter EAAT2 is responsible for up to 90% of all glutamate transport. We will discuss the effect of different neuroprotective tools (membrane stabilizers or endogenous neuroprotection) affecting glutamate efflux and/or expression of EAAT2. We will also describe the finding of a novel polymorphism in the EAAT2 promoter region which could be responsible for differences in both gene function and regulation under pathological conditions such as cerebral ischemia, and which might well account for the failure of glutamate antagonists in the clinical practice. These results may possess important therapeutic implications in the management of patients at risk of ischemic events, since it has been demonstrated that those patients with progressing stroke have higher plasma concentrations of glutamate which remain elevated up to 24 h when compared to the levels in patients without neurological deterioration.

TNFR1 mediates increased neuronal membrane EAAT3 expression after in vivo cerebral ischemic preconditioning

A short ischemic event (ischemic preconditioning) can result in subsequent resistance to severe ischemic injury (ischemic tolerance). Glutamate is released after ischemia and produces cell death. It has been described that after ischemic preconditioning, the release of glutamate is reduced. We have shown that an in vitro model of ischemic preconditioning produces upregulation of glutamate transporters which mediates brain tolerance. We have now decided to investigate whether ischemic preconditioning-induced glutamate transporter upregulation takes also place in vivo, its cellular localization and the mechanisms by which this upregulation is controlled. A period of 10 min of temporary middle cerebral artery occlusion was used as a model of ischemic preconditioning in rat. EAAT1, EAAT2 and EAAT3 glutamate transporters were found in brain from control animals. Ischemic preconditioning produced an up-regulation of EAAT2 and EAAT3 but not of EAAT1 expression. Ischemic preconditioning-induced increase in EAAT3 expression was reduced by the TNF-alpha converting enzyme inhibitor BB1101. Intracerebral administration of either anti-TNF-alpha antibody or of a TNFR1 antisense oligodeoxynucleotide also inhibited ischemic preconditioning-induced EAAT3 up-regulation. Immunohistochemical studies suggest that, whereas the expression of EAAT3 is located in both neuronal cytoplasm and plasma membrane, ischemic preconditioning-induced up-regulation of EAAT3 is mainly localized at the plasma membrane level. In summary, these results demonstrate that in vivo ischemic preconditioning increases the expression of EAAT2 and EAAT3 glutamate transporters the upregulation of the latter being at least partly mediated by TNF-alpha converting enzyme/TNF-alpha/TNFR1 pathway.

Effect of subacute and chronic immobilisation stress on the outcome of permanent focal cerebral ischaemia in rats

The aim of this study was to determine the effect of mood disorders, including psychological distress and depression, on stroke outcome. Male Fischer rats were exposed to immobilisation stress, an animal paradigm of psychological stress, major depression and post-traumatic stress disorder. Either a subacute (1 h for 7 days) or a chronic (6 h for 21 days) exposure to stress was applied 24 h before permanent middle cerebral artery occlusion (MCAO). Stroke outcome was assessed by measurement of infarct size and behavioural characterisation. Serum glutamate and brain ATP levels as well as brain glutamate transporter function and expression were studied in the search for the molecular mechanisms involved. Subacute stress exposure increased infarct size and decreased behavioural scores after stroke. On the contrary, chronic stress exposure decreased infarct size. Peak serum glutamate levels correlated with infarct size after MCAO. Expression of glutamate transporters was decreased by subacute stress, whereas the expression of EAAT1, a glial glutamate carrier, was increased after the chronic stress protocol. Our results indicate that distinct patterns of stress determine different stroke outcomes, and that expressional changes of brain glutamate transporters, able to affect glutamate release after stroke, are involved.

Implication of TNF-alpha convertase (TACE/ADAM17) in inducible nitric oxide synthase expression and inflammation in an experimental model of colitis

Tumour necrosis factor-alpha (TNF-alpha) is a pro-inflammatory cytokine which is shed in its soluble form by a disintegrin and metalloproteinase (ADAM) called TNF-alpha convertase (TACE; ADAM17). TNF-alpha plays a role in inflammatory bowel disease (IBD) and is involved in the expression of inducible nitric oxide synthase (iNOS) which has also been implicated in IBD. The study was designed to investigate whether colitis induced by trinitrobenzene sulphonic acid (TNBS) in rats produces an increase in TACE activity and/or expression and whether its pharmacological inhibition reduces TNF-alpha levels, iNOS expression and colonic damage in this model. TNBS (30 mg in 0.4 ml of 50% ethanol) was instilled into the colon of female Wistar rats. Saline or TACE inhibitor BB1101 (10 mg/kg/day) was administered intraperitoneally 5 days after TNBS instillation. On day 10, colons were removed and assessed for pathological score, myeloperoxidase (MPO), NO synthase (NOS), TACE enzymatic activity and protein levels, colonic TNF-alpha and NOx- levels. Instillation of TNBS caused an increase in TACE activity and expression and the release of TNF-alpha. TNBS also resulted in iNOS expression and colonic damage. BB1101 blocked TNBS-induced increase in TACE activity, TNF-alpha release and iNOS expression. Concomitantly, BB1101 ameliorated TNBS-induced colonic damage and inflammation. TNBS causes TNF-alpha release by an increase in TACE activity and expression and this results in the expression of iNOS and subsequent inflammation, suggesting that TACE inhibition may prove useful as a therapeutic means in IBD.

Neuroprotective effect of aspirin by inhibition of glutamate release after permanent focal cerebral ischaemia in rats

Aspirin reduces the size of infarcts after ischaemic stroke. Although this fact has been attributed to its anti-platelet actions, direct neuroprotective effects have also been reported. We have recently demonstrated that aspirin is neuroprotective by inhibiting glutamate release in 'in vitro' models of brain ischaemia, via an increase in ATP production. The present study was designed to determine whether the inhibition of glutamate release induced by aspirin might be protective in a whole-animal model of permanent focal brain ischaemia. Focal brain ischaemia was produced in male adult Fischer rats by occluding both the common carotid and middle cerebral arteries. Central and serum glutamate levels were determined at fixed intervals after occlusion. The animals were then killed and infarct volume was measured. Aspirin (30 mg/kg i.p. administered 2 h before the occlusion) produced a significant reduction in infarct volume, an effect that correlated with the inhibition caused by aspirin on ischaemia-induced increase in brain and serum glutamate concentrations after the onset of the ischaemia. Aspirin also inhibited ischaemia-induced decrease in brain ATP levels. Our present findings show a novel mechanism for the neuroprotective effects of aspirin, which takes place at concentrations in the anti-aggregant-analgesic range, useful in the management of patients with risk of ischaemic events.

Influence of insulin-like growth factor-I and its interaction with gonadotropins, estradiol, and fetal calf serum on in vitro maturation and parthenogenic development in equine oocytes

The effects of insulin-like growth factor-I (IGF-I) and its interaction with gonadotropins, estradiol, and fetal calf serum (FCS) on in vitro maturation (IVM) of equine oocytes were investigated in this study. We also examined the role of IGF-I in the presence or absence of gonadotropins, estradiol, and FCS in parthenogenic cleavage after oocyte activation with calcium ionophore combined with 6-dimethylaminopurine (6-DMAP), using cleavage rate as a measure of cytoplasmic maturation. Only equine cumulus-oocyte complexes with compact cumulus and homogenous ooplasm (n = 817) were used. In experiment 1, oocytes were cultured in TCM-199 supplemented with BSA, antibiotics, and IGF-I at 0 (control), 50, 100, 200 ng/ml, at 39 degrees C in air with 5% CO(2), 95% humidity for 36 or 48 h. In experiment 2, oocytes were cultured with FSH, LH, estradiol, and FCS with IGF-I at the concentration that promoted the highest nuclear maturation rate in experiment 1. In experiment 3, oocytes from the three experimental groups (IGF-I; hormones; and IGF-I + hormones) were chemically activated by exposure to calcium ionophore followed by culture in 6-DMAP. In experiment 1, IGF-I stimulated equine oocyte maturation in a dose-dependent manner with the highest nuclear maturation rate at a concentration of 200 ng/ml. No significant effect of IGF-I on nuclear maturation was observed in experiment 2. In experiment 3, a significant difference in cleavage rate was observed between the hormone + IGF-I group (15 of 33; 45.4%) compared with IGF-I (10 of 36; 27.8%) and hormone (4 of 31; 12.9%) alone (P < 0.05). These results demonstrated that IGF-I has a positive effect on nuclear maturation rate of equine oocytes in vitro. The addition of IGF-I to an IVM medium containing hormones and FCS did not increase nuclear maturation, but resulted in a positive effect on cytoplasmic maturation of equine oocytes measured by parthenogenic cleavage.

Concentration of collagen, aggrecan and cartilage oligomeric matrix protein (COMP) in synovial fluid from equine middle carpal joints

The aim of the present investigation was to study the metabolic activity of the third carpal bone and the release of COMP, aggrecan and collagen type II molecules in the synovial fluid as a result of injury. Cartilage oligomeric matrix protein (COMP), aggrecan and collagen type II or fragments of these molecules released to the synovial fluid and serum (COMP) were quantified in samples from 73 left equine middle carpal joints from 2 breeds with different activity profiles (52 Standardbred trotters [STB] and 21 Swedish Warmblood riding horses [SWH]) and different articular cartilage lesions. Synovial and serum samples were analysed using inhibition ELISA for COMP and aggrecan. An ELISA that combines features of both the competitive and capture ELISAs was used for collagen type II. COMP and aggrecan concentrations decreased in synovial fluid from the joints with moderate lesions of STB compared with the normal joints; COMP from 16.6 to 12.0 microg/ml and aggrecan from 93.0 to 68.1 microg/ml. In serum, COMP concentrations were also lowered in the STB with moderate lesions compared with the normal joints, while in the SWH, the COMP concentration in synovial fluids from joints with moderate lesions was somewhat increased at 19.6 microg/ml compared with the normal joints (17.6 microg/ml). The ratio between aggrecan/COMP in the synovial fluid from joints with moderate lesions was higher in the STB (6.2) than in the SWH (3.4). The level of collagen type II in synovial fluid was higher in the SWH (8.8 microg/ml) than the STB (1.6 microg/ml), but there was no correlation between joint damage and collagen concentrations in synovial fluids (10.0 and 1.8 microg/ml in joints with moderate lesions from SWH and STB, respectively). A marked difference in COMP synthesised upon metabolic labelling between the normal and osteoarthritic cartilage was seen and the synthesis of COMP in the articular cartilage of the third carpal bone with moderate articular lesions (from an STB) was lower than in the joint with mild lesions. This difference between breeds may reflect different load characters, in release of macromolecules in osteoarthritic and normal joints. This a novel finding that should be considered in studies of equine traumatic arthritis.

N-(3-(aminomethyl)benzyl)acetamidine, an inducible nitric oxide synthase inhibitor, decreases colonic inflammation induced by trinitrobenzene sulphonic acid in rats

Gastrointestinal inflammation has been associated with an increased generation of nitric oxide (NO) and the expression of the inducible NO synthase (iNOS). Using an experimental model of colitis induced by trinitrobenzene sulphonic acid (TNBS), we sought to determine whether the administration of N-(3-(Aminomethyl)benzyl)acetamidine (1400W), a specific inhibitor of iNOS, has a beneficial action on the colonic injury. 1400W (0.4 and 2 mg/kg/day) was administered intraperitoneally from day 5 to 10 after intrarectal instillation of TNBS. TNBS led to colonic ulceration and inflammation, an increase of colonic myeloperoxidase activity and the expression of the calcium-independent NOS from days 1 to 15. 1400W reduced the macroscopic damage and the histological changes induced by TNBS as well as the calcium-independent NOS activity and myeloperoxidase activity determined over 30 min after sacrifice. These findings indicate that the expression of iNOS accounts for most of the damage caused by TNBS and that the administration of 1400W after the onset of colitis has a beneficial action on the colonic injury.

Up-regulation of TNF-alpha convertase (TACE/ADAM17) after oxygen-glucose deprivation in rat forebrain slices

Tumour necrosis factor-alpha (TNF-alpha) is a major immunomodulatory and proinflammatory cytokine which is shed in its soluble form by a membrane-anchored zinc protease, identified as a disintegrin and metalloproteinase (ADAM) called TNF-alpha convertase (TACE; ADAM17). The role of this protease in the adult nervous system remains poorly understood. During cerebral ischemia and subsequent reperfusion, expression and release of TNF-alpha have been shown. We have investigated the expression and activity of TACE in an in vitro model of brain ischemia consisting of rat forebrain slices exposed to oxygen-glucose deprivation (OGD). OGD caused the release of TNF-alpha, an effect which was inhibited by a hydroxamate-based metalloprotease inhibitor, BB-3103, with an IC(50) of 0.1 microM, suggesting that TNF-alpha release results selectively from TACE activity. Assay of TACE enzymatic activity on a fluorescein-labelled peptide spanning the cleavage site in pro-TNF-alpha, as well as Western blot and RT-PCR analyses showed that TACE is present in control forebrain and, more interestingly, that TACE expression is increased in OGD-exposed tissue. TACE enzymatic activity from OGD-exposed slices was significantly inhibited by cycloheximide, suggesting that de novo synthesis of TACE contributes to TNF-alpha release after ischaemia. Moreover, it was also inhibited by bisindolylmaleimide I, indicating that TACE activity is regulated by PKC. These findings posed the question of what was its function therein. Among other actions, TNF-alpha has been described to be involved in the expression of inducible nitric oxide synthase (iNOS), a high-output NOS isoform associated to cellular damage, but the link between TNF-alpha release after brain ischaemia and iNOS expression in this condition has not been shown. We have now found that iNOS expression in OGD-subjected brain slices is inhibited by BB-3103 at concentrations below 1 microM, indicating that shedding of TNF-alpha by TACE plays a necessary part in the induction of this NOS isoenzyme after OGD. Taken together, these data demonstrate that (1) TACE/ADAM17 activity accounts for the majority of TNF-alpha shedding after OGD in rat forebrain slices, (2) an increase in TACE expression contributes, at least in part, to the rise in TNF-alpha after OGD and (3) iNOS expression in OGD-subjected brain slices results from TACE activity and subsequent increase in TNF-alpha levels.

Identification and characterization of asporin. a novel member of the leucine-rich repeat protein family closely related to decorin and biglycan

Asporin, a novel member of the leucine-rich repeat family of proteins, was partially purified from human articular cartilage and meniscus. Cloning of human and mouse asporin cDNAs revealed that the protein is closely related to decorin and biglycan. It contains a putative propeptide, 4 amino-terminal cysteines, 10 leucine-rich repeats, and 2 C-terminal cysteines. In contrast to decorin and biglycan, asporin is not a proteoglycan. Instead, asporin contains a unique stretch of aspartic acid residues in its amino-terminal region. A polymorphism was identified in that the number of consecutive aspartate residues varied from 11 to 15. The 8 exons of the human asporin gene span 26 kilobases on chromosome 9q31.1-32, and the putative promoter region lacks TATA consensus sequences. The asporin mRNA is expressed in a variety of human tissues with higher levels in osteoarthritic articular cartilage, aorta, uterus, heart, and liver. The deduced amino acid sequence of asporin was confirmed by mass spectrometry of the isolated protein resulting in 84% sequence coverage. The protein contains an N-glycosylation site at Asn(281) with a heterogeneous oligosaccharide structure and a potential O-glycosylation site at Ser(54). The name asporin reflects the aspartate-rich amino terminus and the overall similarity to decorin.

Glutathione depletion, lipid peroxidation and mitochondrial dysfunction are induced by chronic stress in rat brain

Damage to the mitochondrial electron transport chain has been suggested to be an important factor in the pathogenesis of a range of neurodegenerative disorders. We have previously demonstrated that chronic stress induced an increase in nitric oxide (NO) production via an expression of inducible NO synthase (iNOS) in brain. Since it has been demonstrated that NO regulates mitochondrial function, we sought to study the susceptibility of the mitochondrial respiratory chain complexes to chronic restrain stress exposure in brain cortex. In adult male rats, stress (immobilization for six hours during 21 days) inhibits the activities of the first complexes of the mitochondrial respiratory chain (inhibition of 69% in complex I-III and of 67% in complex II-III), without affecting complex IV activity, ATP production and oxygen consumption. The mitochondrial marker citrate synthase is not significantly affected by stress after 21 days, indicating that at this time the mitochondrial structure is still intact. Moreover, the administration of the preferred inducible nitric oxide synthase (iNOS) inhibitor aminoguanidine (400 mg/kg i.p. daily from days 7 to 21 of stress) protects against the inhibition of the activity of complexes of the mitochondrial respiratory chain as well as prevents NO(x)(-) accumulation, lipid peroxidation and glutathione depletion induced by stress. These results suggest that a sustained overproduction of NO via iNOS is responsible, at least in part, of the inhibition of mitochondrial respiratory chain caused by stress and that this pathway also accounts for the oxidative stress found in this situation.

Age-related changes in the synthesis and mRNA expression of decorin and aggrecan in human meniscus and articular cartilage

OBJECTIVE

To determine if the biosynthesis of aggrecan and decorin in the human meniscus and the potential of the cells to express these macromolecules (mRNA), is affected by the age of the individual and that if any changes are observed are they different to those measured in articular cartilage obtained from the same joint.

DESIGN

Radiolabelling of tissue explants, anion-exchange chromatography and agarose-polyacrylamide gel electrophoresis were used to analyze newly synthesized proteoglycans. A quantitative, competitive reverse-transcriptase polymerase chain reaction was developed and applied to the tissue to measure the expression of decorin and aggrecan mRNA.

RESULTS

Proteoglycan synthesis in the meniscus was higher in young donors (1-5 mmoles sulfate incorporated/h/mgDNA, under 20 years of age) than in adult tissues (0.5-1 mmoles incorporated/h/mgDNA, 20-62 years of age) and decorin was the major proteoglycan synthesized at this time. An age-related increase in the proportion of aggrecan synthesis in the meniscus was also observed using agarose-polyacrylamide gel electrophoresis. Both decorin (five-fold) and aggrecan (eight-fold) mRNA expression increased with age in meniscus whereas levels were relatively constant in articular cartilage. In addition, the synthesis of decorin and aggrecan and the expression of their mRNA was different in meniscus and articular cartilage from the same knee joint.

CONCLUSION

The synthesis and turnover of aggrecan and decorin in the human meniscus is influenced by the age of the individual and is not the same as that observed for articular cartilage.

Inducible nitric oxide synthase expression in brain cortex after acute restraint stress is regulated by nuclear factor kappaB-mediated mechanisms

The underlying mechanisms by which physical or psychological stress causes neurodegeneration are still unknown. We have demonstrated that the high-output and long-lasting synthesizing source of nitric oxide (NO), inducible NO synthase (iNOS), is expressed in brain cortex during stress and that its overexpression accounts for the neurodegenerative changes seen after 3 weeks of repeated stress. Now we have found that acute stress (restraint for 6 h) increases the activity of a calcium-independent NOS and induces the expression of iNOS in brain cortex in adult male rats. In order to elucidate the possible mechanisms involved in this induction, we studied the role of transcription nuclear factor kappaB (NF-kappaB), which is required for iNOS synthesis. We have observed that an acute restraint stress session stimulates the translocation of the NF-kappaB to the nucleus after 4 h and that the administration of the NF-kappaB inhibitor pyrrolidine dithiocarbamate [PDTC, 75 and 150 mg/kg intraperitoneally (i.p.)] at the onset of stress inhibits the stress-induced increase in iNOS expression. Since glutamate release and subsequent NMDA (N-methyl-D-aspartate) receptor activation has been recognized as an early change after exposure to stressful stimuli, and glutamate has been shown to induce iNOS in brain via a NF-kappaB-dependent mechanism, we studied the possible role of excitatory amino acids in the induction of iNOS in our model. Pretreatment with the NMDA receptor antagonist dizocilpine (MK-801, 0.1 and 0.3 mg/kg i.p.) inhibits the stress-induced NF-kappaB activation as well as the stress-induced increase in iNOS expression. Taken together, these findings indicate that excitatory amino acids and subsequent activation of NF-kappaB account for stress-induced iNOS expression in cerebral cortex, and support a possible neuroprotective role for specific inhibitors in this situation.

Fructose-1,6-bisphosphate inhibits the expression of inducible nitric oxide synthase caused by oxygen-glucose deprivation through the inhibition of glutamate release in rat forebrain slices

Fructose-1,6-bisphosphate (FBP) is a glycolytic pathway intermediate with a neuroprotective action in animal models of brain ischaemia. We addressed the question of whether FBP acts through inhibiting inducible nitric oxide synthase (iNOS) expression via reduction of glutamate release, since we have recently demonstrated that glutamate is involved in the expression of iNOS. FBP (5 mM) added to the incubation solution of rat forebrain slices subjected to oxygen-glucose deprivation (OGD) inhibited glutamate release significantly (around 40%). FBP also inhibited the induction of the calcium-independent NOS activity and reduced the levels of iNOS protein in rat forebrain slices subjected to OGD. We conclude that the action of FBP by reducing glutamate release and iNOS expression, both of which have been implicated in cell damage, is a reason for further evaluation of FBP as a neuroprotectant.

Up-regulation of cartilage oligomeric matrix protein at the onset of articular cartilage degeneration in a transgenic mouse model of osteoarthritis

OBJECTIVE

To investigate the suitability of cartilage oligomeric matrix protein (COMP) as a marker for articular cartilage degeneration in a transgenic mouse model of osteoarthritis (OA).

METHODS

Northern blot analysis of total RNA extracted from the knee joints of transgenic Del1 mice, which harbor a short deletion in a type II collagen transgene, and of their nontransgenic littermates was used to monitor changes in COMP messenger RNA (mRNA) levels during cartilage degeneration. Immunohistochemistry was used to determine the distribution of COMP in articular cartilage, and serum levels of COMP were measured by immunoassay.

RESULTS

Transient up-regulation of COMP mRNA was seen in articular cartilage of transgenic Del1 mice at the onset of OA lesions at the age of 3 months. Compared with nontransgenic controls, COMP immunostaining of articular cartilage in 3-9-month-old transgenic mice was increased, especially at the border of uncalcified and calcified cartilage. There was also a change from predominantly interterritorial to pericellular/territorial deposition of COMP. This difference persisted until the age of 15 months, when the nontransgenic controls also demonstrated articular cartilage degeneration and increased COMP immunostaining. Increased serum levels of COMP were seen in Del1 mice at the age of 4 months, correlating temporally with the onset of cartilage degeneration.

CONCLUSION

These findings suggest that upregulation of COMP mRNA and redistribution of the protein are characteristic of the early stages of articular cartilage degeneration in the transgenic mouse model in which OA results from a dominant-negative mutation in the type II collagen gene. The data provide additional support for the notion that COMP is a useful marker for altered cartilage metabolism in developing OA.

pT3.2I, the smallest plasmid of Thiobacillus T3.2

The whole nucleotide sequence of pT3.2I, the smallest plasmid of the acidophilic bacterium Thiobacillus T3.2, has been determined. pT3.2I is 15,390 bp long with a 53.7% GC content. Different regions can be defined in it: one 2569-bp putative insertion sequence similar to other insertion sequences of some Agrobacterium Ti plasmids; and a longer sequence, which occurs in two almost identical copies, differing only in a 1-bp deletion (6406 and 6405 bp). Several open reading frames and some smaller sequences were found in this duplicated region: ORFA and ORFG, encoding a putative polyol dehydrogenase and a putative RepA replication protein, respectively, an 83-bp sequence which could code for an antisense RNA, and a 36-bp region highly homologous to ori sequences of ColE2- and ColE3-related plasmids. Another putative gene, ORFH, is only present in the longer copy of this region (it is deleted in the short copy) and might encode a 90-amino-acid polypeptide which could act as a second replication protein, RepB. Based on sequence comparisons, pT3. 2I can be related to plasmids in the pColE2-CA42 incB incompatibility group.

Implication of glutamate in the expression of inducible nitric oxide synthase after oxygen and glucose deprivation in rat forebrain slices

Nitric oxide synthesis by inducible nitric oxide synthase (iNOS) has been postulated to contribute to ischemia-reperfusion neurotoxicity. The expression of this enzyme has been demonstrated in cells present in the postischemic brain. The mechanisms of iNOS expression after cerebral ischemia are a subject of current research. We therefore decided to investigate whether glutamate, which is released in ischemia and is implicated in neurotoxicity, might be involved in the mechanisms by which oxygen and glucose deprivation (OGD) leads to the expression of iNOS in rat forebrain slices. In this model, we have shown previously that 20 min of OGD causes the expression of iNOS. We have now found that the NMDA receptor antagonist MK-801 blocks the expression of iNOS, suggesting that the activation of the NMDA subtype of glutamate receptor is implicated in the mechanisms that lead to the expression of this isoform. Moreover, we have found that glutamate alone could trigger the induction process, as shown by the appearance of a Ca(2+)-independent NOS activity and by the detection of iNOS mRNA and protein in slices exposed to glutamate. Glutamate-dependent iNOS expression was concentration-dependent and was blocked by EGTA and by the inhibitors of nuclear factor kappaB (NF-kappaB) activation pyrrolidine dithiocarbamate and MG132. In addition, glutamate induced NF-kappaB translocation to the nucleus, an effect that was inhibited by MG132. Taken together, our data suggest that activation of NMDA receptors by glutamate released in ischemia is involved in the expression of iNOS in rat forebrain slices via a Ca(2+)-dependent activation of the transcription factor NF-kappaB. To our knowledge, this is the first report showing an implication of excitatory amino acids in the expression of iNOS caused by ischemia.

Mechanisms of the neuroprotective effect of aspirin after oxygen and glucose deprivation in rat forebrain slices

Acetylsalicylic acid (ASA, Aspirin) is an anti-inflammatory drug with a wide spectrum of pharmacological activities and multiple sites of action. Apart from its preventive actions against stroke due to its antithrombotic properties, recent data in the literature suggest that high concentrations of ASA also exert direct neuroprotective effects. We have used an in vitro model of brain ischaemia using rat forebrain slices deprived of oxygen and glucose to test ASA neuroprotective properties. We have found that ASA inhibits neuronal damage at concentrations lower than those previously reported (0.1-0.5 mM), and that these effects correlate with the inhibition of excitatory amino acid release, of NF-kappaB translocation to the nucleus and iNOS expression caused by ASA. All of these three mechanisms may mediate the neuroprotective effects of this drug. Our results also show that the effects of ASA are independent of COX inhibition. Taken together, our present findings show that ASA is neuroprotective in an in vitro model of brain ischaemia at doses close to those recommended for its antithrombotic effects.