The role of propylene glycol metabolism in lactatemia in the rabbit.

Propylene glycol (1,2-propanediol PD) has been reported to significantly alter the blood parameters when administered as a drug vehicle. In this study, experiments were performed to estimate the pH, levels of PD, and its metabolites to determine the acute effect of PD in blood. PD was administered to rabbits orally in a single dose of 1 ml 28.4% aqueous solution per 100 g body weight equivalent to 38.66 mmol/kg. Whole blood pH and the levels of PD and metabolites were estimated at fast (O.O h, before feeding PD) and at 0.25, 1, and 3 h after the dose. PD elevated the concentrations of blood PD to its maximum (41.04 +/- 9.98 mmol/liter, n = 4) at 1 h; whereas blood PD is normally absent during fasting. PD significantly increased (P less than 0.01) the concentration of L-lactate in blood, which reached its plateau (2.55 +/- 0.62 mmol/liter, n = 4) at 0.25 h and was 2.45-fold higher than the observed fasted values (1.04 +/- 0.22 mmol/liter, n = 4). Production of D-lactate in blood was similarly increased significantly from 5.1 +/- 5.0 mumols/liter at fast to 150.0 +/- 30.4 mumols/liter at 3 h after oral PD (P less than 0.001, n = 4). As was observed in the fasted blood of PD treated rabbits, D-lactate levels at fast and after saline ingestion in the control animals was found either absent or too low. Despite this increase in lactate, blood pH did not alter significantly when appropriate anticoagulant, i.e., heparin + 4-methylpyrazole, was employed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Sall4 isoforms act during proximal-distal and anterior-posterior axis formation in the mouse embryo

Reciprocal signals from embryonic and extra-embryonic tissues pattern the embryo in proximal-distal (PD) and anterior-posterior (AP) fashion. Here we have analyzed three gene trap mutations of Sall4, of which one (Sall4-1a) led to a hypomorphic and recessive phenotype, demonstrating that Sall4-1a has yet undescribed extra-embryonic and embryonic functions in regulating PD and AP axis formation. In Sall4-1a mutants the self-maintaining autoregulatory interaction between Bmp4, Nodal and Wnt, which determines the PD axis was disrupted because of defects in the extra-embryonic visceral endoderm. More severely, two distinct Sall4 gene-trap mutants (Sall4-1a,b), resembling null mutants, failed to initiate Bmp4 expression in the extra-embryonic ectoderm and Nodal in the epiblast and were therefore unable to initiate PD axis formation. Tetraploid rescue underlined the extra-embryonic nature of the Sall4-1a phenotype and revealed a further embryonic function in Wnt/beta-catenin signaling to elongate the AP axis during gastrulation. This observation was supported through genetic interaction with beta-catenin mutants, since compound heterozygous mutants recapitulated the defects of Wnt3a mutants in posterior development.     

Interaction of inhaled LTC4 with histamine and PGD2 on airway caliber in asthma

To investigate possible mediator interaction in asthma, the effect of inhaled leukotriene (LT) C4 on bronchoconstriction provoked by histamine and prostaglandin (PG) D2 was studied in nine asthmatic subjects. The provocation doses of histamine, PGD2, and LTC4 required to produce a 12.5% decrease in baseline forced expiratory volume in 1 s (FEV1, PD12.5) and to further this fall to 25% (PD25-12.5) were determined. On three subsequent occasions, subjects inhaled either the PD12.5 LTC4 plus vehicle or vehicle plus the PD25-12.5 of either histamine or PGD2, and FEV1 and maximal flow at 70% of vital capacity below total lung capacity after a forced partial expiratory maneuver (Vp30) followed for 45 min. From these results, predicted time-course curves for LTC4 with histamine and LTC4 with PGD2 were calculated. On two final occasions, airway caliber was followed for 45 min after inhalation of the PD12.5 LTC4 followed by the PD25-12.5 of either histamine or PGD2. During the first 9 min after LTC4-histamine and LTC4-PGD2, the decreases in airway caliber were greater than the calculated predicted response. This interaction, although small, was significant with LTC4-PGD2 for both FEV1 (P = 0.01) and Vp30 (P less than 0.05) and with LTC4-histamine for Vp30 (P less than 0.05) but not for FEV1 (P less than 0.05). We conclude that inhaled LTC4 interacts synergistically with histamine and PGD2 and that this effect, although small, may be a relevant interaction in asthma.     

Co-crystal structure and inhibition of factor Xa by PD0313052 identifies structurally stabilized active site residues of factor Xa and prothrombinase

The enzyme complex prothrombinase plays a pivotal role in fibrin clot development through the production of thrombin, making this enzyme complex an attractive target for therapeutic regulation. This study both functionally and structurally characterizes a potent, highly selective, active site directed inhibitor of human factor Xa and prothrombinase, PD0313052, and identifies structurally conserved residues in factor Xa and prothrombinase. Analyses of the association and dissociation of PD0313052 with human factor Xa identified a reversible, slow-onset mechanism of inhibition and a simple, single-step bimolecular association between factor Xa and PD0313052. This interaction was governed by association (k(on)) and dissociation (k(off)) rate constants of (1.0 +/- 0.1) x 10(7) M(-1) s(-1) and (1.9 +/- 0.5) x 10(-3) s(-1), respectively. The inhibition of human factor Xa by PD0313052 displayed significant tight-binding character described by a Ki* = 0.29 +/- 0.08 nM. Similar analyses of the inhibition of human prothrombinase by PD0313052 also identified a slow-onset mechanism with a Ki* = 0.17 +/- 0.03 nM and a k(on) and k(off) of (0.7 +/- 0.1) x 10(7) M(-1) s(-1) and (1.7 +/- 0.8) x 10(-3) s(-1), respectively. Crystals of factor Xa and PD0313052 demonstrated hydrogen bonding contacts within the S1-S4 pocket at residues Ser195, Asp189, Gly219, and Gly216, as well as interactions with aromatic residues within the S4 pocket. Overall, these data demonstrate that the inhibition of human factor Xa by PD0313052 occurs via a slow, tight-binding mechanism and indicate that active site residues of human factor Xa, including the catalytic Ser195, are effectively unaltered following assembly into prothrombinase.     

Solution structure of a Hck SH3 domain ligand complex reveals novel interaction modes

We studied the interaction of hematopoietic cell kinase SH3 domain (HckSH3) with an artificial 12-residue proline-rich peptide PD1 (HSKYPLPPLPSL) identified as high affinity ligand (K(D)=0.2 muM). PD1 shows an unusual ligand sequence for SH3 binding in type I orientation because it lacks the typical basic anchor residue at position P(-3), but instead has a tyrosine residue at this position. A basic lysine residue, however, is present at position P(-4). The solution structure of the HckSH3:PD1 complex, which is the first HckSH3 complex structure available, clearly reveals that the P(-3) tyrosine residue of PD1 does not take the position of the typical anchor residue but rather forms additional van der Waals interactions with the HckSH3 RT loop. Instead, lysine at position P(-4) of PD1 substitutes the function of the P(-3) anchor residue. This finding expands the well known ligand consensus sequence +xxPpxP by +xxxPpxP. Thus, software tools like iSPOT fail to identify PD1 as a high-affinity HckSH3 ligand so far. In addition, a short antiparallel beta-sheet in the RT loop of HckSH3 is observed upon PD1 binding. The structure of the HckSH3:PD1 complex reveals novel features of SH3 ligand binding and yields new insights into the structural basics of SH3-ligand interactions. Consequences for computational prediction tools adressing SH3-ligand interactions as well as the biological relevance of our findings are discussed.     

Neurodegeneration and motor dysfunction in mice lacking cytosolic and mitochondrial aldehyde dehydrogenases: implications for Parkinson's disease

Previous studies have reported elevated levels of biogenic aldehydes in the brains of patients with Parkinson's disease (PD). In the brain, aldehydes are primarily detoxified by aldehyde dehydrogenases (ALDH). Reduced ALDH1 expression in surviving midbrain dopamine neurons has been reported in brains of patients who died with PD. In addition, impaired complex I activity, which is well documented in PD, reduces the availability of the NAD(+) co-factor required by multiple ALDH isoforms to catalyze the removal of biogenic aldehydes. We hypothesized that chronically decreased function of multiple aldehyde dehydrogenases consequent to exposure to environmental toxins and/or reduced ALDH expression, plays an important role in the pathophysiology of PD. To address this hypothesis, we generated mice null for Aldh1a1 and Aldh2, the two isoforms known to be expressed in substantia nigra dopamine neurons. Aldh1a1(-/-)×Aldh2(-/-) mice exhibited age-dependent deficits in motor performance assessed by gait analysis and by performance on an accelerating rotarod. Intraperitoneal administration of L-DOPA plus benserazide alleviated the deficits in motor performance. We observed a significant loss of neurons immunoreactive for tyrosine hydroxylase (TH) in the substantia nigra and a reduction of dopamine and metabolites in the striatum of Aldh1a1(-/-)×Aldh2(-/-) mice. We also observed significant increases in biogenic aldehydes reported to be neurotoxic, including 4-hydroxynonenal (4-HNE) and the aldehyde intermediate of dopamine metabolism, 3,4-dihydroxyphenylacetaldehyde (DOPAL). These results support the hypothesis that impaired detoxification of biogenic aldehydes may be important in the pathophysiology of PD and suggest that Aldh1a1(-/-)×Aldh2(-/-) mice may be a useful animal model of PD.     

经蛋白A连接于琼脂糖的单克隆抗体亲和层析柱用于抗独特型抗体的纯化

 以Sepharose CL-4B-Pro A吸附胃癌单克隆抗体(McAb)PD4,继之以交联剂二甲基庚二亚胺二盐酸盐(dimethyl pimelimidate dihydrochloride)处理,形成亲和介质(柱Ⅰ)。该亲和介质用于纯化抗PD4独特型抗体(aIdAb)具有明显的优点。与Sepharose CL-4B-PD4(柱Ⅱ)相比,前者的结合容量为后者的1.78～1.94倍。采用柱Ⅰ纯化的aIdAb,当其与McAb PD4的分子比分别为1:1及4:1时可50％或100％地抑制McAb PD4与靶细胞的结合,但采用柱Ⅱ获得的aIdAb,只有当分子比达到2:1及8:1时,才能达到同等的抑制效应。这可能是由于Pro A与McAb PD4的Fc片断结合,使后者的Fab端得以充分暴露,因而有更多的机会与aIdAb结合。     

Endogenous neurotoxic dopamine derivative covalently binds to Parkinson's disease‐associated ubiquitin C‐terminal hydrolase L1 and alters its structure and function

Parkinson's disease (PD) is a common neurodegenerative disease, but its pathogenesis remains elusive. A mutation in ubiquitin C‐terminal hydrolase L1 (UCH‐L1) is responsible for a form of genetic PD which strongly resembles the idiopathic PD. We previously showed that 1‐(3′,4′‐dihydroxybenzyl)‐1,2,3,4‐tetrahydroisoquinoline (3′,4′DHBnTIQ) is an endogenous parkinsonism‐inducing dopamine derivative. Here, we investigated the interaction between 3′,4′DHBnTIQ and UCH‐L1 and its possible role in the pathogenesis of idiopathic PD. Our results indicate that 3′,4′DHBnTIQ binds to UCH‐L1 specifically at Cys152 in vitro. In addition, 3′,4′DHBnTIQ treatment increased the amount of UCH‐L1 in the insoluble fraction of SH‐SY5Y cells and inhibited its hydrolase activity to 60%, reducing the level of ubiquitin in the soluble fraction of SH‐SY5Y cells. Catechol‐modified UCH‐L1 as well as insoluble UCH‐L1 were detected in the midbrain of 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine‐treated PD model mice. Structurally as well as functionally altered UCH‐L1 have been detected in the brains of patients with idiopathic PD. We suggest that conjugation of UCH‐L1 by neurotoxic endogenous compounds such as 3′,4′DHBnTIQ might play a key role in onset and progression of idiopathic PD.

     

Control of hepatic nuclear superoxide production by glucose 6-phosphate dehydrogenase and NADPH oxidase-4

Redox-regulated signal transduction is coordinated by spatially controlled production of reactive oxygen species within subcellular compartments. The nucleus has long been known to produce superoxide (O(2)(·-)); however, the mechanisms that control this function remain largely unknown. We have characterized molecular features of a nuclear superoxide-producing system in the mouse liver. Using electron paramagnetic resonance, we investigated whether several NADPH oxidases (NOX1, 2, and 4) and known activators of NOX (Rac1, Rac2, p22(phox), and p47(phox)) contribute to nuclear O(2)(·-) production in isolated hepatic nuclei. Our findings demonstrate that NOX4 most significantly contributes to hepatic nuclear O(2)(·-) production that utilizes NADPH as an electron donor. Although NOX4 protein immunolocalized to both nuclear membranes and intranuclear inclusions, fluorescent detection of NADPH-dependent nuclear O(2)(·-) predominantly localized to the perinuclear space. Interestingly, NADP(+) and G6P also induced nuclear O(2)(·-) production, suggesting that intranuclear glucose-6-phosphate dehydrogenase (G6PD) can control NOX4 activity through nuclear NADPH production. Using G6PD mutant mice and G6PD shRNA, we confirmed that reductions in nuclear G6PD enzyme decrease the ability of hepatic nuclei to generate O(2)(·-) in response to NADP(+) and G6P. NOX4 and G6PD protein were also observed in overlapping microdomains within the nucleus. These findings provide new insights on the metabolic pathways for substrate regulation of nuclear O(2)(·-) production by NOX4.     

Dopamine-induced epithelial K(+) and Na(+) movements in the salivary ducts of Periplaneta americana

K(+)- and Na(+)-selective double-barrelled microelectrodes were used for intracellular and luminal measurements in salivary ducts of Periplaneta americana. The salivary ducts were stimulated with dopamine (10(-6) mol l(-1)). Dopamine decreased intracellular [K(+)] from 112+/-17 mmol l(-1) to 40+/-13 mmol l(-1) (n=6) and increased intracellular [Na(+)] from 22+/-19 mmol l(-1) to 92+/-4 mmol l(-1) (n=6). Luminal [K(+)] was 15+/-3 mmol l(-1) in the unstimulated salivary ducts and increased to 26+/-11 mmol l(-1) upon stimulation with dopamine (n=10). Luminal [Na(+)] was insignificantly increased from 105+/-25 mmol l(-1) to 116+/-22 mmol l(-1) (n=12) by stimulation with dopamine. The potential difference across the basolateral membrane (PD(b)) was depolarized from -65+/-6 mV to -31+/-13 mV (n=12) and the transepithelial potential difference (PD(t)) was hyperpolarized from -13+/-6 mV to -22+/-7 mV (n=22, lumen negative) upon stimulation with dopamine. The re-establishment of prestimulus values of intracellular [K(+)] and [Na(+)] and PD(b) was inhibited by basolateral addition of ouabain (10(-4) mol l(-1)). Furosemide (10(-4) mol l(-1)) in the bath inhibited the dopamine-induced increase in intracellular [Na(+)], the decrease in intracellular [K(+)] and the depolarization of PD(b). We propose a model for dopamine-stimulated ion transport in the salivary ducts involving basolateral Na(+)-K(+)-2Cl(-) cotransport and active extrusion of K(+) via the apical membrane.     

Microsomal hexose-6-phosphate dehydrogenase in injured liver.

Hexose-6-phosphate dehydrogenase (H6PD) in rat liver microsomes was clearly differentiated kinetically, immunologically and electrophoretically from glucose-6-phosphate dehydrogenase (G6PD) localized in liver supernatants. Although the soluble G6PD activity increased upon liver injuries induced by CCl4 and thioacetamide, the H6PD activity decreased markedly 1-2 days following administrations of these hepatotoxins. The specific activity of H6PD remained fairly constant under other experimental conditions where the levels of the soluble G6PD activity increased.     

Avian colonic ion transport: effects of corticosterone and dexamethasone

1. Corticosterone, a natural corticosteroid hormone in birds, when injected into domestic fowl (Gallus domesticus) (2000 micrograms.kg-1, 4-5 h before experiment) increases both the basal Isc (short-circuit current) and amiloride-sensitive Isc as well as the PD across the colon in vitro. Dexamethasone, a synthetic analogue (650 micrograms.kg-1, 4-5 h before experiment) also increases the basal and amiloride-sensitive Isc as well as PD in these preparations. 2. In marked contrast, longer term injection or infusion of dexamethasone (650 micrograms.kg-1) for 3 or more days caused a decline in basal Isc and PD (the PD often reversed with the serosal side becoming electronegative) and a drop in resistance. However in these preparations, the amiloride-sensitive Isc was significantly elevated which could be accounted for by an increase in net Na flux. 3. No significant change occurs in net flux of Cl or K although unidirectional fluxes in both directions were increased for both ions in birds given dexamethasone for 3 days. 4. A disparity between the basal Isc and the amiloride-sensitive Isc appeared in these preparations from dexamethasone injected birds reflecting the transport of other ions, possibly HCO3- or H+. The possible role of corticosterone in mineral metabolism of birds is discussed.     

Alternative targeting of Arabidopsis plastidic glucose-6-phosphate dehydrogenase G6PD1 involves cysteine-dependent interaction with G6PD4 in the cytosol

Arabidopsis peroxisomes contain an incomplete oxidative pentose-phosphate pathway (OPPP), consisting of 6-phosphogluconolactonase and 6-phosphogluconate dehydrogenase isoforms with peroxisomal targeting signals (PTS). To start the pathway, glucose-6-phosphate dehydrogenase (G6PD) is required; however, G6PD isoforms with obvious C-terminal PTS1 or N-terminal PTS2 motifs are lacking. We used fluorescent reporter fusions to explore possibly hidden peroxisomal targeting information. Among the six Arabidopsis G6PD isoforms only plastid-predicted G6PD1 with free C-terminal end localized to peroxisomes. Detailed analyses identified SKY as an internal PTS1-like signal; however, in a medial G6PD1 reporter fusion with free N- and C-terminal ends this cryptic information was overruled by the transit peptide. Yeast two-hybrid analyses revealed selective protein-protein interactions of G6PD1 with catalytically inactive G6PD4, and of both G6PD isoforms with plastid-destined thioredoxin m2 (Trx(m2) ). Serine replacement of redox-sensitive cysteines conserved in G6PD4 abolished the G6PD4-G6PD1 interaction, albeit analogous changes in G6PD1 did not. In planta bimolecular fluorescence complementation (BiFC) demonstrated that the G6PD4-G6PD1 interaction results in peroxisomal import. BiFC also confirmed the interaction of Trx(m2) with G6PD4 (or G6PD1) in plastids, but co-expression analyses revealed Trx(m2) -mediated retention of medial G6PD4 (but not G6PD1) reporter fusions in the cytosol that was stabilized by CxxC113S exchange in Trx(m2) . Based on preliminary findings with plastid-predicted rice G6PD isoforms, we dismiss Arabidopsis G6PD4 as non-functional. G6PD4 orthologs (new P0 class) apparently evolved to become cytosolic redox switches that confer thioredoxin-relayed alternative targeting to peroxisomes.     

PD 102807, a novel muscarinic M4 receptor antagonist, discriminates between striatal and cortical muscarinic receptors coupled to cyclic AMP

In membranes of Chinese hamster ovary cells expressing the cloned human M1-M4 muscarinic receptor subtypes, PD 102807, a novel M4 selective antagonist, was found to counteract the M4 receptor-induced stimulation of [35S]-GTPgammaS binding to membrane G proteins with a pK(B) of 7.40, a value which was 63-, 33- and 10-fold higher than those displayed at M1 (pK(B) = 5.60), M2 (pK(B) = 5.88) and M3 (pK(B) = 6.39) receptor subtypes, respectively. In rat striatal membranes, PD 102807 antagonized the muscarinic inhibition of dopamine (DA) D1 receptor-stimulated adenylyl cyclase with a pK(B) value of 7.36. In contrast, in membranes of rat frontal cortex, PD 102807 displayed lower potencies in antagonizing either the muscarinic facilitation of corticotropin releasing hormone (CRH)-stimulated adenylyl cyclase (pK(B) = 5.79) or inhibition of Ca2+/calmodulin (Ca2+/CaM)-stimulated enzyme activity (pK(B) = 5.95). In each response investigated, PD 102807 interacted with muscarinic receptors in a manner typical of a simple competitive antagonist. These data provide additional evidence that PD 102807 is a M4-receptor preferring antagonist and that this compound can discriminate the striatal muscarinic receptors inhibiting DA D1 receptor activity from the cortical receptors mediating the potentiation of CRH receptor signalling and the inhibition of Ca2+/CaM-stimulated adenylyl cyclase activity.     

Protective effects of PEP-1-Catalase on stress-induced cellular toxicity and MPTP-induced Parkinson’s disease

Parkinson’s disease (PD) is a neurodegenerative disability caused by a decrease of dopaminergic neurons in the substantia nigra (SN). Although the etiology of PD is not clear, oxidative stress is believed to lead to PD. Catalase is antioxidant enzyme which plays an active role in cells as a reactive oxygen species (ROS) scavenger. Thus, we investigated whether PEP-1-Catalase protects against 1-methyl-4-phenylpyridinium (MPP⁺) induced SH-SY5Y neuronal cell death and in a 1-methyl-4-phenyl-1,2,3,6-trtrahydropyridine (MPTP) induced PD animal model. PEP-1-Catalase transduced into SH-SY5Y cells significantly protecting them against MPP⁺-induced death by decreasing ROS and regulating cellular survival signals including Akt, Bax, Bcl-2, and p38. Immunohistochemical analysis showed that transduced PEP-1-Catalase markedly protected against neuronal cell death in the SN in the PD animal model. Our results indicate that PEP-1-Catalase may have potential as a therapeutic agent for PD and other oxidative stress related diseases. [BMB Reports 2015; 48(7): 395-400]     

Transmembrane electropotential in barley roots as related to cell type, cell location, and cutting and aging effects

Transmembrane electropotential difference (PD) was measured in whole roots of barley (Hordeum vulgare L. cvs. Compana and Himalaya). Seedlings were grown 4 to 5 days in aerated 0.5 mm CaSO(4) or a nutrient solution. Measurements of PD were made with roots bathed in CaSO(4), KCl + CaSO(4), or the nutrient solution. The following results were found. (a) There was a radial PD gradient with epidermal cells being 10 to 58 millivolts less negative than cells in the third layer of the cortex (outside to inside). There was no longitudinal PD gradient in the region 0.5 to 4 cm from the root tip, nor was there any difference between the PD of young root hairs and other epidermal cells. (b) Cell PD in excised whole roots was not detectably different from that found in roots attached to the shoot, and was unchanged for 2 hours from excision. (c) In 1-centimeter sections of root, cell PD at the freshly cut surface was depolarized by 90 millivolts from that in the intact root; cells farther than 1 millimeter from the cut surface were not depolarized. The PD of cells at the cut surface became more negative upon aging the segment in 0.5 mm CaSO(4), eventually becoming greater by -25 millivolts than that in cells of intact roots. Cells in segments to which the root tips were attached had less negative PDs after aging than those in subapical segments, indicating a possible hormonal effect. PDs in aged, excised segments are not equivalent to those in intact roots. (d) Creeping of cytoplasm over electrode tips inserted into the vacuole gave measurements of vacuole-to-cytoplasm PD of + 9 millivolts in 0.5 mm CaSO(4) and + 35 millivolts in 1 mm KCl + 0.5 mm CaSO(4). Most of the cell PD was across the plasmalemma. (e) The reducing sugar content of roots in CaSO(4) solution was greater than that of roots in the nutrient solution in which ion uptake, particularly K(+) occurred.     

Anti-inflammatory actions of neuroprotectin D1/protectin D1 and its natural stereoisomers: assignments of dihydroxy-containing docosatrienes

Protectin D1, neuroprotectin D1 when generated by neural cells, is a member of a new family of bioactive products generated from docosahexaenoic acid. The complete stereochemistry of protectin D1 (10,17S-docosatriene), namely, chirality of the carbon-10 alcohol and geometry of the conjugated triene, required for bioactivity remained to be assigned. To this end, protectin D1/neuroprotectin D1 (PD1) generated by human neutrophils during murine peritonitis and by neural tissues was separated from natural isomers and subjected to liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry. Comparisons with six 10,17-dihydroxydocosatrienes prepared by total organic and biogenic synthesis showed that PD1 from human cells carrying potent bioactivity is 10R,17S-dihydroxy-docosa-4Z,7Z,11E,13E,15Z,19Z-hexaenoic acid. Additional isomers identified included trace amounts of Delta15-trans-PD1 (isomer III), 10S,17S-dihydroxy-docosa-4Z,7Z,11E,13Z,15E,19Z-hexaenoic acid (isomer IV), and a double dioxygenation product 10S,17S-dihydroxy-docosa-4Z,7Z,11E,13Z,15E,19Z-hexaenoic acid (isomer I), present in exudates. 18O2 labeling showed that 10S,17S-diHDHA (isomer I) carried 18O in the carbon-10 position alcohol, indicating sequential lipoxygenation, whereas PD1 formation proceeded via an epoxide. PD1 at 10 nM attenuated (approximately 50%) human neutrophil transmigration, whereas Delta15-trans-PD1 was essentially inactive. PD1 was a potent regulator of polymorphonuclear leukocyte (PMN) infiltration (approximately 40% at 1 ng/mouse) in peritonitis. The rank order at 1- to 10-ng dose was PD1 approximately PD1 methyl ester > Delta15-trans-PD1 > 10S,17S-diHDHA (isomer I). 10S,17S-dihydroxy-docosa-4Z,7Z,11E,13E,15Z,19Z-hexaenoic acid (isomer VI) proved > or = PD1 in blocking PMN infiltration, but was not a major product of leukocytes. PD1 also reduced PMN infiltration after initiation (2 h) of inflammation and was additive with resolvin E1. These results indicate that PD1 is a potent stereoselective anti-inflammatory molecule.     

Dual inhibition of monoamine oxidase B and antagonism of the adenosine A(2A) receptor by (E,E)-8-(4-phenylbutadien-1-yl)caffeine analogues

The adenosine A(2A) receptor has emerged as an attractive target for the treatment of Parkinson's disease (PD). Evidence suggests that antagonists of the A(2A) receptor (A(2A) antagonists) may be neuroprotective and may help to alleviate the symptoms of PD. We have reported recently that several members of the (E)-8-styrylcaffeine class of A(2A) antagonists also are potent inhibitors of monoamine oxidase B (MAO-B). Since MAO-B inhibitors are known to possess anti-parkinsonian properties, dual-target-directed drugs that block both MAO-B and A(2A) receptors may have enhanced value in the management of PD. In an attempt to explore this concept further we have prepared three additional classes of C-8 substituted caffeinyl analogues. The 8-phenyl- and 8-benzylcaffeinyl analogues exhibited relatively weak MAO-B inhibition potencies while selected (E,E)-8-(4-phenylbutadien-1-yl)caffeinyl analogues were found to be exceptionally potent reversible MAO-B inhibitors with enzyme-inhibitor dissociation constants (K(i) values) ranging from 17 to 149 nM. Furthermore, these (E,E)-8-(4-phenylbutadien-1-yl)caffeines acted as potent A(2A) antagonists with K(i) values ranging from 59 to 153 nM. We conclude that the (E,E)-8-(4-phenylbutadien-1-yl)caffeines are a promising candidate class of dual-acting compounds.