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Supplementary Figure from Exploiting Ligand-binding Domain Dimerization for Development of Novel Androgen Receptor Inhibitors

Supplementary Table from Exploiting Ligand-binding Domain Dimerization for Development of Novel Androgen Receptor Inhibitors

The mitochondrial glutaminase enzymes initiate glutaminolysis by catalyzing the hydrolysis of glutamine to glutamate, satisfying the metabolic requirements of aggressive cancers and thus representing potential therapeutic targets. However, the mechanisms underlying their allosteric regulation are poorly understood. It has been suggested that glutaminases form oligomeric filament-like structures essential for their activation. Here, we provide structural evidence for the ability of the glutaminase enzymes to form filaments upon substrate binding, and present the first cryo-EM structures of the human full-length glutaminase isozyme GLS2 that offer an unprecedented view of the mechanism responsible for catalyzing glutamine hydrolysis. The GLS2 structures reveal that the ‘activation loop’, a motif previously identified to regulate enzymatic activity, assumes a unique conformation and works together with a ‘lid’ that closes over the active site to ‘lock in’ the substrate glutamine. Tyrosine 251 of the GLS2 activation loop forms a cation-π interaction with Lysine 222 in the active site, which in turn enables a key catalytic residue, Serine 219, to undergo deprotonation for nucleophilic attack on the substrate. These findings further suggest that allosteric glutaminase inhibitors disrupt this interaction, which is critical for catalysis, while activators stabilize it. The GLS2 structures also show how the ankyrin repeats regulate different glutaminase isozymes.

Metabolic reprogramming is a major hallmark of malignant transformation in cancer, and part of the so-called Warburg effect, in which the upregulation of glutamine catabolism plays a major role. The glutaminase enzymes convert glutamine to glutamate, which initiates this pathway. Inhibition of different forms of glutaminase (KGA, GAC, or LGA) demonstrated potential as an emerging anti-cancer therapeutic strategy. The regulation of these enzymes, and the molecular basis for their inhibition, have been the focus of much recent research. This review will explore the recent progress in understanding the molecular basis for activation and inhibition of different forms of glutaminase, as well as the recent focus on combination therapies of glutaminase inhibitors with other anti-cancer drugs.

Currently, all clinically used androgen receptor (AR) antagonists target the AR ligand-binding pocket and inhibit T and dihydrotestosterone (DHT) binding. Resistance to these inhibitors in prostate cancer frequently involves AR-dependent mechanisms resulting in a retained AR dependence of the tumor. More effective or alternative AR inhibitors are therefore required to limit progression in these resistant stages. Here, we applied the structural information of the ligand-binding domain (LBD) dimerization interface to screen in silico for inhibitors. A completely new binding site, the Dimerisation Inhibiting Molecules (DIM) pocket, was identified at the LBD dimerization interface. Selection of compounds that fit the DIM pocket via virtual screening identified the DIM20 family of compounds which inhibit AR transactivation and dimerization of the full-length AR as well as the isolated LBDs. Via biolayer interferometry, reversible dose-dependent binding to the LBD was confirmed. While DIM20 does not compete with 3H-DHT for binding in the LBP, it limits the maximal activity of the AR indicative of a noncompetitive binding to the LBD. DIM20 and DIM20.39 specifically inhibit proliferation of AR-positive prostate cancer cell lines, with only marginal effects on AR-negative cell lines such as HEK 293 and PC3. Moreover, combination treatment of DIM compounds with enzalutamide results in synergistic antiproliferative effects which underline the specific mechanism of action of the DIM compounds.

Cancer cells frequently exhibit uncoupling of the glycolytic pathway from the TCA cycle (i.e., the “Warburg effect”) and as a result, often become dependent on their ability to increase glutamine catabolism. The mitochondrial enzyme Glutaminase C (GAC) helps to satisfy this ‘glutamine addiction’ of cancer cells by catalyzing the hydrolysis of glutamine to glutamate, which is then converted to the TCA-cycle intermediate α-ketoglutarate. This makes GAC an intriguing drug target and spurred the molecules derived from bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulfide (the so-called BPTES class of allosteric GAC inhibitors), including CB-839, which is currently in clinical trials. However, none of the drugs targeting GAC are yet approved for cancer treatment and their mechanism of action is not well understood. Here, we shed new light on the underlying basis for the differential potencies exhibited by members of the BPTES/CB-839 family of compounds, which could not previously be explained with standard cryo-cooled X-ray crystal structures of GAC bound to CB-839 or its analogs. Using an emerging technique known as serial room temperature crystallography, we were able to observe clear differences between the binding conformations of inhibitors with significantly different potencies. We also developed a computational model to further elucidate the molecular basis of differential inhibitor potency. We then corroborated the results from our modeling efforts using recently established fluorescence assays that directly read out inhibitor binding to GAC. Together, these findings should aid in future design of more potent GAC inhibitors with better clinical outlook.

Many cancer cells become dependent on glutamine metabolism to compensate for glycolysis being uncoupled from the TCA cycle. The mitochondrial enzyme Glutaminase C (GAC) satisfies this ‘glutamine addiction’ by catalyzing the first step in glutamine metabolism, making it an attractive drug target. Despite one of the allosteric inhibitors (CB-839) being in clinical trials, none of the drugs targeting GAC are approved for cancer treatment and their mechanism of action is not well understood. A major challenge has been the rational design of better drug candidates: standard cryo-cooled X-ray crystal structures of GAC bound to CB-839 and its analogs fail to explain their potency differences. Here, we address this problem by using an emerging technique, serial room temperature crystallography, which enabled us to observe clear differences between the binding conformations of inhibitors with significantly different potencies. A computational model was developed to further elucidate the molecular basis of inhibitor potency. We then corroborated the results from our modeling efforts by using recently established fluorescence assays that directly read-out inhibitor binding to GAC. Together, these findings provide new insights into the mechanisms used by a major class of allosteric GAC inhibitors and for the future rational design of more potent drug candidates.

Background:For the treatment of peritoneal dialysis-associated peritonitis (PDAP), ceftazidime is routinely admixed with peritoneal dialysis (PD) solutions before its intraperitoneal administration. One of the major degradation products of ceftazidime is pyridine, a potentially toxic compound. Depending on the type of PD solution, ceftazidime is exposed to an environment with acidic or basic pH, and depending on the type of dosing and individual unit practices related to preparation and storage, ceftazidime can be at body temperature for 4–10 h, resulting in potentially varying rates of degradation to pyridine by-product. No study has investigated whether the amount of generated pyridine exceeds the maximum daily exposure limit of 2 mg when ceftazidime-PD admixtures are kept at body temperature. Therefore, the current study aimed to determine the levels of pyridine generated in PD-ceftazidime admixtures kept at 37°C for various time points.Methods:Ceftazidime was admixed with 2 L Dianeal (1.5%, 2.5% and 4.25% dextrose) and 2 L Physioneal (1.36%, 2.27% and 3.86% glucose) PD solutions to obtain a concentration of 125 mg/L (continuous dosing model) or 500 mg/L (intermittent dosing model). A total of 36 PD admixtures (3 bags for each type of PD solution and 3 bags for each type of dosing) were prepared and stored at 37°C for 10 h. An aliquot was withdrawn at time 0 (baseline) and after 2, 6, 8 and 10 h of storage. The withdrawn samples were then analysed to determine the concentrations of ceftazidime and pyridine using high-performance liquid chromatography.Results:With the intermittent dosing model (500 mg/L), ceftazidime was found to be stable for only 2 and 6 h when admixed with 3.86% and 2.27% glucose Physioneal PD solutions, respectively. While ceftazidime (500 mg/L) retained more than 90% of its initial concentration in the three types of Dianeal and 1.36% dextrose Physioneal solutions for 10 and 8 h, respectively, the generated amount of pyridine ranged between approximately 290% and 371% more than the daily recommended limit. With the continuous dosing model (125 mg/L), ceftazidime was found to be stable for 6 h in all three types of Physioneal PD solutions, but the total amount of generated pyridine with four daily exchanges (6 h each) was estimated to be 170–360% over the daily recommended limit. Ceftazidime (125 mg/L) was chemically stable when admixed with three types of Dianeal PD solutions and stored at 37°C for 10 h, and the levels of pyridine were estimated to be less than the maximum recommended daily limit.Conclusions:Until the outcomes of this in vitro study are confirmed by appropriate in vivo studies, continuous dosing of ceftzadime–Dianeal admixtures for the treatment of PDAP may be preferred over continuous dosing of ceftazidime–Physioneal admixtures, and intermittent dosing of ceftazidime–Physioneal and ceftazidime–Dianeal admixtures, as ceftazidime remains stable and the generated levels of pyridine are below the maximum recommended daily exposure.

Background Asian-Americans are one of the most understudied racial/ethnic minority populations. To increase representation of Asian subgroups, researchers have traditionally relied on data collection at community venues and events. However, the COVID-19 pandemic has created serious challenges for in-person data collection. In this case study, we describe multi-modal strategies for online recruitment of U.S. Vietnamese parents, compare response rates and participant characteristics among strategies, and discuss lessons learned. Methods We recruited 408 participants from community-based organizations (CBOs) (n = 68), Facebook groups (n = 97), listservs (n = 4), personal network (n = 42), and snowball sampling (n = 197). Using chi-square tests and one-way analyses of variance, we compared participants recruited through different strategies regarding sociodemographic characteristics, acculturation-related characteristics, and mobile health usage. Results The overall response rate was 71.8% (range: 51.5% for Vietnamese CBOs to 86.6% for Facebook groups). Significant differences exist for all sociodemographic and almost all acculturation-related characteristics among recruitment strategies. Notably, CBO-recruited participants were the oldest, had lived in the U.S. for the longest duration, and had the lowest Vietnamese language ability. We found some similarities between Facebook-recruited participants and those referred by Facebook-recruited participants. Mobile health usage was high and did not vary based on recruitment strategies. Challenges included encountering fraudulent responses (e.g., non-Vietnamese). Perceived benefits and trust appeared to facilitate recruitment. Conclusions Facebook and snowball sampling may be feasible strategies to recruit U.S. Vietnamese. Findings suggest the potential for mobile-based research implementation. Perceived benefits and trust could encourage participation and may be related to cultural ties. Attention should be paid to recruitment with CBOs and handling fraudulent responses.

The naphthalene sulfonamide scaffold is known to possess CCR8 antagonistic properties. In order to expand the structure-activity relationship study of this compound class, a variety of palladium-catalyzed cross-coupling reactions was performed on a bromo-naphthalene precursor yielding a diverse library. These compounds displayed CCR8 antagonistic properties in binding and calcium mobilization assays, with IC50 values in the 0.2 - 10 µM range. The decreased activity, when compared to the original lead compound, was rationalized by homology molecular modeling. ispartof: BIOORGANIC CHEMISTRY vol:107 ispartof: location:United States status: published

Introduction Asian-Americans have been documented to have low human papillomavirus (HPV) vaccine initiation and completion. No research has attempted to examine underlying mechanisms of HPV vaccine uptake disparities among Asian-Americans. Using the P3 (practice, provider, and patient) model, this study aimed to identify practice-, provider-, and patient-level determinants of Asian-Americans’ HPV vaccine intention and uptake. Methods We conducted a systematic review of published literature regarding practice-, provider- and patient-level determinants of vaccine intention (e.g., intention, willingness, or acceptability) and uptake (e.g., initiation or completion). Eligible studies were those presenting empirical/original data, focusing on Asian populations in the U.S., including outcomes related to HPV vaccine intention and uptake, and analyzing data on factors associated with these outcomes separately for Asian groups. Results Twenty-six studies (19 quantitative and 7 qualitative studies) were included in the review. Most commonly studied subgroups were Koreans (n = 9), Chinese (n = 6), and Cambodians (n = 5). Studies showed varied prevalence across subgroups (intention: 23.4%–72%; initiation: 14%–67%; completion: 9%–63%). Only 3 studies included measurements of practice-level determinants (language services, insurance policy). Twelve studies measured provider-level determinants (most commonly documented: HPV vaccine recommendation). All studies measured patient-level determinants (most commonly documented: HPV and HPV vaccine knowledge, perceived safety, perceived susceptibility, and perceived relationship between HPV vaccine and sexual activity). Conclusions Existing research on determinants of HPV vaccine intention and uptake among Asian-Americans currently lacks measurements of practice-level constructs and perspectives of clinic staff and providers, which are needed to guide system-level interventions and provider training. Data regarding patient-level determinants suggest that interventions for Asian-American populations can focus on providing educational information in culturally-appropriate manners, leveraging familial influences, and attending to access-related or cultural beliefs about HPV vaccine. Interventions should take into account varied vaccine intention and uptake prevalence in different Asian subgroups.

The mitochondrial enzyme glutaminase C (GAC) is upregulated in many cancer cells to catalyze the first step in glutamine metabolism, the hydrolysis of glutamine to glutamate. The dependence of cancer cells on this transformed metabolic pathway highlights GAC as a potentially important therapeutic target. GAC acquires maximal catalytic activity upon binding to anionic activators such as inorganic phosphate. To delineate the mechanism of GAC activation, we used the tryptophan substitution of tyrosine 466 in the catalytic site of the enzyme as a fluorescent reporter for glutamine binding in the presence and absence of phosphate. We show that in the absence of phosphate, glutamine binding to the Y466W GAC tetramer exhibits positive cooperativity. A high-resolution X-ray structure of tetrameric Y466W GAC bound to glutamine suggests that cooperativity in substrate binding is coupled to tyrosine 249, located at the edge of the catalytic site (i.e., the "lid"), adopting two distinct conformations. In one dimer within the GAC tetramer, the lids are open and glutamine binds weakly, whereas, in the adjoining dimer, the lids are closed over the substrates, resulting in higher affinity interactions. When crystallized in the presence of glutamine and phosphate, all four subunits of the Y466W GAC tetramer exhibited bound glutamine with closed lids. Glutamine can bind with high affinity to each subunit, which subsequently undergo simultaneous catalysis. These findings explain how the regulated transitioning of GAC between different conformational states ensures that maximal catalytic activity is reached in cancer cells only when an allosteric activator is available.

A new 1,8-naphthalimide-based fluorescent probe for the detection of diethyl cyanophosphonate, a very common nerve agent simulant, is designed, synthesized, and characterized fully. The probe shows around 50-fold enhancement of fluorescence intensity over other nerve agent simulants. Importantly, the probe is able to work under aqueous conditions in a wide pH range. Two reactive groups, the oxime and the phenol, allow a dual emission with different kinetic reactions. The reaction of diethyl cyanophosphonate with the oxime group occurs in advance; the resulting time response of the fluorescence enhancement is observed within approximately 30 s. After the oxime reaction, then phenol also undergoes a substitution reaction with diethyl cyanophosphonate, resulting in a blue emission. The real application of this new probe is demonstrated through the use of silica plate assays for the detection of diethyl cyanophosphonate in both gas and liquid phases through dual emission channels.

Cryptococcus neoformans is a yeast within the division Basidiomycota that may cause pulmonary and central nervous system (CNS) disease. Latex agglutination (LA) and lateral flow assay (LFA) for detection of cryptococcal polysaccharide antigen are sensitive and specific tests for diagnosis of

Multiple duct anastomoses during LLS transplantation increase the incidence of biliary complications. The optimal plane of hepatotomy that results in the least number of bile ducts at the surface was investigated according to LHD variations. Ducts of 30 human livers were injected with resin and LHD branching on 3D-CT reconstructions were analyzed. Ducts on the virtual hepatotomy surface were estimated in three splitting lines. Variations with subtypes were described. Ia (66.7%): ducts from segments (S.) II-III form a common trunk and S.IV duct joins it. Ib (10%): common trunk formed by ducts from S.II-S.III while S.IV duct joins the common hepatic duct. IIa (16.67%): S.IV duct drains into S.III duct. IIc (3.33%): S.IV duct drains into both S.II and S.III ducts. III (3.33%): trifurcation of S.II, S.III and S.IV ducts. When the virtual hepatotomy line was on the FL, there was a single duct for the anastomosis in 30% of cases but two, three, or four ducts in 53.3%, 10%, and 3.3%, respectively. Division 1 cm to the right of the FL resulted in one duct (70%), but S.IV duct injury may occur. LLS hepatotomy should not necessarily be performed along the FL. Variations must be taken into consideration to minimize the number of biliary anastomoses during liver implantation.

This paper presents an indirect matrix converter (IMC) topology to fed an open-end winding load directly from three-phase ac power supply without using any intermediate energy storage element. The presented topology is combined a conventional bidirectional rectifier stage and dual two-level inverter stage. The carrier-based pulse width modulation (CBPWM) suitable to this converter controlled is also presented. The proposed CBPWM is easily implemented by compared the high frequency carrier signals with the reference signals to generate the gating signals for all power switches in the converter. Theory analysis and simulation results are provided to show the effectiveness of the proposed method.

The common Group 1 alkali metals are indeed ubiquitous on earth, in the oceans and in biological systems. In this introductory chapter, concepts involving aqueous chemistry and aspects of general coordination chemistry and oxygen atom donor chemistry are introduced. Also, there are nuclear isotopes of importance. A general discussion of Group 1 begins from the prevalence of the ions, and from a comparison of their ionic radii and ionization energies. While oxygen and water molecule binding have the most relevance to biology and in forming a detailed understanding between the elements, there is a wide range of basic chemistry that is potentially important, especially with respect to biological chelation and synthetic multi-dentate ligand design. The elements are widely distributed in life forms, in the terrestrial environment and in the oceans. The details about the workings in animal, as well as plant life are presented in this volume. Important biometallic aspects of human health and medicine are introduced as well. Seeing as the elements are widely present in biology, various particular endogenous molecules and enzymatic systems can be studied. Sodium and potassium are by far the most important and central elements for consideration. Aspects of lithium, rubidium, cesium and francium chemistry are also included; they help in making important comparisons related to the coordination chemistry of Na(+) and K(+). Physical methods are also introduced.

Cardiomyocyte development switches from hyperplasmic to hypertrophic growth between postnatal days 3 and 4 in rats. The mechanisms responsible for this transition have been controversial. beta-Adrenergic receptor (betaAR) activation of mitogenic responses in vitro has been reported. We hypothesized that tonic activation of the betaAR signaling regulates cell division in neonatal cardiomyocytes via effects on signaling kinases known to be important in cell cycle regulation. The purpose of the current study was to elucidate the roles of betaAR in rat cardiomyocyte growth in vivo. We demonstrated that betaAR blockade induced a significant reduction in cardiomyocyte proliferation as measured by the BrdU labeling index. Blockade of betaAR did not affect p38 or p44/42 MAPK activities. We further demonstrated that betaAR blockade induced a prompt deactivation of the p70 ribosomal protein S6 kinase (p70 S6K). To confirm these results, we measured p70 S6K activity directly. Basal activity of p70 S6K in neonatal cardiomyocytes was fourfold higher than that of insulin-treated adult rat liver. The activity of p70 S6K was reduced by 60% within 1 min after betaAR blockade. We conclude that the betaAR are involved in regulation of neonatal cardiomyocyte proliferation and that this mitogenic control may be mediated via the p70 S6K pathway.

A plasticity model studying the adult rat barrel cortex intrinsic signal after a central lesion was developed. Repeated optical imaging studies of the barrel cortex of five rats were performed over variable periods of time (2 days to 6 weeks) after intracortical injection of kainic acid. The signal of the elicited principal whisker corresponding to the injected barrel in the repeat studies relocated to the perimeter of the lesion. The area of the signals of this principal whisker and of surrounding whiskers were larger in the first two weeks studies than those obtained before injection (P0.01) resulting in increase overlapping of adjacent signals (P=0.01). Even though the signal of the PW remains relocated in the later studies (2 weeks), all the signals returned to normal size. These findings demonstrate recovery and reorganization of sensory representation in the somatosensory cortex following a central lesion.

The biogenic amine transporters are part of a large family of plasma membrane transporters. These carriers mediate the re-uptake of neurotransmitters from the synaptic cleft and plasma compartments. Re-uptake process is inhibited by drugs like cocaine, fluoxetine and tricyclic antidepressants. There are specific transporters for norepinephrine, epinephrine, dopamine and serotonin. The placenta expresses the norepinephrine and serotonin transporters, which is unusual as they are otherwise expressed predominantly in neuronal tissue. Fetal catecholamine clearance rate is higher than under any other physiological conditions and is mediated in large measure by the placental transporters. The high intrauterine catecholamine secretion and clearance rates are part of the unique fetal neuroendocrine milieu. They condition the fetus to a high capacity for catecholamine secretion in the early postnatal period when elevated sympathoadrenal system activity is vital for postnatal survival. Because of the prominent catecholamine clearance rate, the fetus is vulnerable to the adverse effects of re-uptake inhibitors. Understanding the mechanisms of expression and regulation of placental biogenic amine transporters is important to the pathobiology of fetal conditions associated with elevated catecholamine levels or intrauterine exposure to uptake inhibitors like cocaine.

We identified an inverted, functional cAMP response element (CRE) located at--1599 bp relative to the translation start site within the ovine beta 1-adrenergic receptor (beta 1 AR) gene promoter. In transfection studies with SK-N-MC cells, a 40-bp oligonucleotide containing the potential CRE, beta 1 AR-CRE, conferred a 3- to 4-fold increase in luciferase activity mediated by cAMP. The induction was mimicked by co-transfecting the cells with a vector overexpressing the alpha-catalytic subunit of the cAMP-dependent protein kinase (PKA) without treatment, and was blocked by overexpressing a PKA inhibitor (PKI). In electrophoretic mobility shift assays, a discrete binding pattern was shown in cell nuclear extract probed with the 40 bp beta 1 AR-CRE. The binding was shown to be specific and supershifted by addition of a CRE binding protein (CREB-1) antibody. These data demonstrate that cAMP mediates the induction of beta 1 AR gene expression by interacting with an inverted CRE within the promoter region. This is the first reported functional CRE among all beta 1 AR genes.

Proteasomes are multisubunit proteases that exist universally among eukaryotes. They have multiple proteolytic activities, and are believed to have important roles in regulating cell cycle, selective intracellular proteolysis, and antigen presentation. To determine the possible role that proteasomes may play in controlling the life cycle of African trypanosomes, we have isolated proteasomes from the bloodstream and the insect (procyclic) forms of Trypanosoma brucei by DEAE-cellulose chromatography and glycerol gradient fractionation in the presence of ATP. No 26 S proteasome homologs was identified in T. brucei under these experimental conditions. The proteasomes isolated from these two forms of T. brucei are very similar to the rat blood cell 20 S proteasome in their general appearance under the electron microscope. The profile of trypanosome proteasome subunits in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) has eight visible protein bands with molecular weights ranging from 23 to 34 kDa, and cross-reacted very poorly with the anti-human 20 S proteasome antibodies on immunoblots. Two-dimensional gel electrophoresis of the parasite proteasomes shows a similar number of major subunits with pI's ranging from 4.5 to 7. Using a variety of fluorogenic peptides as substrates, the trypanosome proteasomes exhibited unusually high trypsin-like, but somewhat lower chymotrypsin-like activities, as compared to the rat 20 S proteasome. These proteolytic activities were, however, insensitive to phenylmethylsulfonyl fluoride (PMSF), tosyl-phenylalanine chloromethylketone (TPCK), tosyl-lysine chloromethylketone (TLCK) and trans-epoxy succinyl-L-leucylamido-(4 guanidino) butane (E-64), but the trypsin-like activity of trypanosome proteasomes was inhibited by leupeptin, an aldehyde known to inhibit the trypsin-like activity of mammalian proteasomes, thus ruling out possible contamination by other serine or cysteine proteases. Some quantitative differences in the substrate specificities between the proteasomes from bloodstream and procyclic forms were indicated, which may play a role in determining the differential protein turnovers at two different stages of development of T. brucei.

Plasticity after microinjection of kainic acid (KA) into the adult rat whisker barrel cortex was investigated with immunohistochemical staining of phosphorylated growth-associated protein (GAP)-43. After mapping the barrel cortex with the technique of intrinsic signal optical imaging, a small volume of KA was injected into one barrel. Rats were sacrificed at 2 days, 3 days, 1 week, and 6 weeks after lesioning. GAP-43 staining demonstrated intense immunoreactivity (IR) at the injected barrel which spread to the inter-barrel septa and the surrounding barrels. Elevated IR of GAP-43 was visible 2 days after KA injection, and increased gradually at least 6 weeks following the lesion. This model has the possibility of offering a simple and reliable tool for studying cortical plasticity.

The placenta expresses high levels of 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2) that converts cortisol into inactive 11-keto metabolites and effectively protects the developing fetus from maternal cortisol during pregnancy. Impairment of this glucocorticoid barrier has adverse effects on fetal outcomes. A similar spectrum of adverse fetal effects is induced by antenatal stress during pregnancy. To examine the hypothesis that physiological stress may regulate placental 11βHSD2 gene expression, we examined the effects of the catecholamines norepinephrine (NE) and epinephrine (E) on 11βHSD2 expression in human trophoblastic cells. With the use of Northern blotting and semiquantitative RT-PCR, we determined that NE and E rapidly downregulate 11βHSD2 steady-state mRNA levels in early- and late-gestation human trophoblasts and BeWo trophoblastic cells. Experiments using different adrenoceptor subtype-selective agonists and antagonists demonstrated that this catecholamine suppression of 11βHSD2 mRNA expression is mediated via both α1- and α2-adrenoceptors and is independent of β-adrenergic stimulation. To examine transcriptional regulation, BeWo cells were transiently transfected with a reporter construct in which an 11βHSD2 human promoter sequence was inserted upstream of the luciferase gene. Treatment with 10−7M NE decreased luciferase activity by ∼60% ( n = 3, P < 0.01). These results suggest the NE/E-mediated decrease in placental 11βHSD2 gene expression is an instance of α-adrenoceptor-specific rapid transcriptional inhibition of an adrenergic target gene. This molecular mechanism may be involved in the deleterious effects of antenatal physiological stress on fetoplacental growth and development.

The effects of glucocorticoids on expression of the beta1-adrenergic receptor (beta1AR) gene have been varied. To study the mechanism underling hormonal regulation of the beta1AR, transient transfection of progressively deleted ovine beta1AR promoter fragments was used to identify a 43-bp region (-1274 to -1232 from the translation start site) that contains a novel glucocorticoid regulatory unit (GRU) and confers glucocorticoid responsiveness. Using DNase I footprinting and electrophoretic mobility shift assays (EMSA), we demonstrated the GRU was composed of a palindrome, 5'-TAATTA-3', which is a core binding motif for the homeodomain proteins, an E-box (5'-CACGTG-3'), binding site for the Myc/Max family proteins, and an overlapping glucocorticoid response element (GRE) half-site (5'-TGTTCT-3'). EMSA demonstrated that the GRE half-site is critical for GRU-protein interactions, which also require binding of proteins to the E-box and the homeodomain region. Co-transfection of a plasmid expressing a c-myc antisense construct significantly reduced glucocorticoid responsiveness of the ovine beta1AR promoter. Furthermore, expression of proteins binding to the GRU was shown to be developmentally regulated, being high in embryonic, reduced in newborn and not detectable in adult heart. We conclude that the ovine beta1AR promoter contains a novel, functional GRU and that glucocorticoid receptor (GR) and the Myc/Max family proteins are involved in the cell-specific nuclear factor binding and transactivation via this element. The results suggest an alternative pathway through which glucocorticoids may exert their effects on genes lacking a full consensus GRE.

We isolated a 2.5-kb fragment of the promoter for the rat norepinephrine transporter (NET) gene. The transcription start site was identified approximately 200 base pairs upstream from the translation start site. Several potential regulatory elements were identified by sequence analysis. The structure of the rat NET promoter was compared to mouse and human. Expression studies in placental and neuroblastoma cells suggested the presence of a 'repressor' element more than 500 base pairs upstream from the transcription start site. These studies provide the basis for examination of transcriptional regulation of this gene and for understanding its temporal and tissue-specific modes of regulation.

Metastasis to the brain occurs in 20%–40% of cancer patients.1 About 20% of these metastases are located in the posterior fossa, cerebellum, and brainstem. Metastatic disease to periventricular brain tissue can obstruct the flow of cerebrospinal fluid (CSF) produced in the ventricles to the subarachnoid space where it is normally absorbed by arachnoid granulations. This typically causes an obstructive or non-communication hydrocephalus. A shunt has been customarily placed to drain CSF from a lateral ventricle through a pressure regulating valve and into the atrium or peritoneal or pleural cavity. Even though this technique has been successful in relieving the hydrocephalus, it has about a 50% chance of infection or failure from blockage.2 Another option for the treatment of obstructive hydrocephalus is third ventriculostomy, a minimal invasive endoscopic neurosurgical procedure. In performing third ventriculostomy, a hole is created in the floor of the third ventricle, allowing CSF inside the ventricle to drain out to the CSF space surrounding …

Two elastase inhibitors, ASPI-1 and ASPI-2, from the parasitic nematode Anisakis simplex , have been isolated and characterized. Because these inhibitors are similar in size (60 amino acids in length) and primary sequence (52 and 47% identical) to the Ascaris suum chymotrypsin/elastase inhibitor-1 (AsC/E-1), we suggest that these Anisakis elastase inhibitors belong to the same unique class of canonical inhibitors formed by the family of Ascaris inhibitors (Huang K, Strynadka NCJ, Bernard VD, Peanasky RJ, James MG. Structure 1994;2:679–689). To compare ASPI-1 with AsC/E-1, we expressed both inhibitors in Pichia pastoris and found that: (1) the association constant of rASPI-1 with porcine pancreatic elastase (PPE) is similar to native inhibitor ( K a =4.5×10 9 and 6.4×10 9 M −1 , respectively); (2) rASPI-1 is a potent inhibitor of PPE and human leukocyte elastase ( K a =1.6×10 9 M −1 ); and (3) it is only a very weak inhibitor of chymotrypsin (CHYM) ( K a =1.2×10 6 M −1 ). In contrast to the Anisakis inhibitor, however, rAsC/E inhibitor-1 is a very strong inhibitor of both PPE ( K a =3.5×10 10 M −1 ) and CHYM ( K a =3.6×10 12 M −1 ). We also found that the determined reactive sites (P 1 –P 1 ′) of rASPI-1 and rAsC/E-1, as recognized by PPE, are Ala 28-Met 29 and Leu 31-Met 32, respectively. These P 1 –P 1 ′ residues of AsC/E-1 constitute the same reactive site as that also recognized by CHYM (Peanasky RJ, Bentz Y, Homandberg GA, Minor ST, Babin DR. Arch Biochem Biophys 1994;232:135–142). The difference in specificities of ASPI-1 and AsC/E-1 toward their cognate serine proteases may be attributed to the P 1 and P 3 ′ residues in the inhibitors. Elastase, which recognizes both alanine and leucine, can accommodate both ascarid inhibitors, whereas chymotrypsin, which prefers bulky, hydrophobic residues, only recognizes the Ascaris C/E inhibitor-1.

The contribution of N-linked carbohydrates to the function of the human norepinephrine transporter (NET) was investigated using site-directed mutagenesis to inactivate the two most carboxy-terminal (NQQ mutant) or all three (QQQ mutant) sites for N-glycosylation within the extracellular loop between transmembrane domains 3 and 4. In HeLa cells transiently expressing the NET, two glycosylated forms of the transporter at 90 and 60 kDa are immunoprecipitated by NET antisera. A single 50-kDa species is observed in cells expressing the QQQ mutant, and it likely represents the NET core protein. Analyses of substrate transport kinetics showed rank order V max of 19 :9 :1 for NET/NQQ/QQQ without a change in the apparent affinity of the wild-type and mutated carriers for either substrates or transport inhibitors. Cell surface biotinylation indicates that all NET, NQQ, and QQQ transporter species are detected at the plasma membrane but that glycosylated forms are selectively enriched. The transport activities exhibited by each of the carriers correlate well with cell surface content. Subcellular localization of transporters using immunofluorescence microscopy shows that reductions in surface expression and transport are associated with a corresponding increase in the intracellular retention of mutated carriers. Thus, N-linked glycosylation does not alter the apparent affinity of NET for either substrates or inhibitors of transport but, instead, appears to influence the abundance of carriers at the cell surface.