Publications by authors named "Robert Gibbs"

40 Publications

Age Impacts the Burden That Reference Memory Imparts on an Increasing Working Memory Load and Modifies Relationships With Cholinergic Activity.

Front Behav Neurosci 2021 10;15:610078. Epub 2021 Feb 10.

Department of Psychology, Arizona State University, Tempe, AZ, United States.

Rodent aging research often utilizes spatial mazes, such as the water radial-arm-maze (WRAM), to evaluate cognition. The WRAM can simultaneously measure spatial working and reference memory, wherein these two memory types are often represented as orthogonal. There is evidence, however, that these two memory forms yield interference at a high working memory load. The current study systematically evaluated whether the presence of a reference memory component impacts handling of an increasing working memory load. Young and aged female rats were tested to assess whether aging impacts this relationship. Cholinergic projections from the basal forebrain to the hippocampus and cortex can affect cognitive outcomes, and are negatively impacted by aging. To evaluate whether age-related changes in working and reference memory profiles are associated with cholinergic functioning, we assessed choline acetyltransferase activity in these behaviorally-tested rats. Results showed that young rats outperformed aged rats on a task testing solely working memory. The addition of a reference memory component deteriorated the ability to handle an increasing working memory load, such that young rats performed similar to their aged counterparts. Aged rats also had challenges when reference memory was present, but in a different context. Specifically, aged rats had difficulty remembering which reference memory arms they had entered within a session, compared to young rats. Further, aged rats that excelled in reference memory also excelled in working memory when working memory demand was high, a relationship not seen in young rats. Relationships between cholinergic activity and maze performance differed by age in direction and brain region, reflecting the complex role that the cholinergic system plays in memory and attentional processes across the female lifespan. Overall, the addition of a reference memory requirement detrimentally impacted the ability to handle working memory information across young and aged timepoints, especially when the working memory challenge was high; these age-related deficits manifested differently with the addition of a reference memory component. This interplay between working and reference memory provides insight into the multiple domains necessary to solve complex cognitive tasks, potentially improving the understanding of complexities of age- and disease- related memory failures and optimizing their respective treatments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fnbeh.2021.610078DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7902531PMC
February 2021

Inhibition of Estrogen Sulfotransferase (/EST) Ameliorates Ischemic Acute Kidney Injury in Mice.

J Am Soc Nephrol 2020 07 18;31(7):1496-1508. Epub 2020 May 18.

Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania

Background: Studies have suggested that estrogens may protect mice from AKI. Estrogen sulfotransferase (, or EST) plays an important role in estrogen homeostasis by sulfonating and deactivating estrogens, but studies on the role of in AKI are lacking.

Methods: We used the renal ischemia-reperfusion model to investigate the role of in AKI. We subjected wild-type mice, knockout mice, and knockout mice with liver-specific reconstitution of expression to bilateral renal ischemia-reperfusion or sham surgery, either in the absence or presence of gonadectomy. We assessed relevant biochemical, histologic, and gene expression markers of kidney injury. We also used wild-type mice treated with the inhibitor triclosan to determine the effect of pharmacologic inhibition of on AKI.

Results: AKI induced the expression of in a tissue-specific and sex-specific manner. It induced expression of in the liver in both male and female mice, but induction in the kidney occurred only in male mice. Genetic knockout or pharmacologic inhibition of protected mice of both sexes from AKI, independent of the presence of sex hormones. Instead, a gene profiling analysis indicated that the renoprotective effect was associated with increased vitamin D receptor signaling. Liver-specific transgenic reconstitution of in knockout mice abolished the protection in male mice but not in female mice, indicating that 's effect on AKI was also tissue-specific and sex-specific.

Conclusions: appears to have a novel function in the pathogenesis of AKI. Our findings suggest that inhibitors of might have therapeutic utility in the clinical management of AKI.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1681/ASN.2019080767DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7351010PMC
July 2020

Hepatic Estrogen Sulfotransferase Distantly Sensitizes Mice to Hemorrhagic Shock-Induced Acute Lung Injury.

Endocrinology 2020 01;161(1)

Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, PA.

Hemorrhagic shock (HS) is a potential life-threatening condition that may lead to injury to multiple organs, including the lung. The estrogen sulfotransferase (EST, or SULT1E1) is a conjugating enzyme that sulfonates and deactivates estrogens. In this report, we showed that the expression of Est was markedly induced in the liver but not in the lung of female mice subject to HS and resuscitation. Genetic ablation or pharmacological inhibition of Est effectively protected female mice from HS-induced acute lung injury (ALI), including interstitial edema, neutrophil mobilization and infiltration, and inflammation. The pulmonoprotective effect of Est ablation or inhibition was sex-specific, because the HS-induced ALI was not affected in male Est-/- mice. Mechanistically, the pulmonoprotective phenotype in female Est-/- mice was accompanied by increased lung and circulating levels of estrogens, attenuated pulmonary inflammation, and inhibition of neutrophil mobilization from the bone marrow and neutrophil infiltration to the lung, whereas the pulmonoprotective effect was abolished upon ovariectomy, suggesting that the protection was estrogen dependent. The pulmonoprotective effect of Est ablation was also tissue specific, as loss of Est had little effect on HS-induced liver injury. Moreover, transgenic reconstitution of human EST in the liver of global Est-/- mice abolished the pulmonoprotective effect, suggesting that it is the EST in the liver that sensitizes mice to HS-induced ALI. Taken together, our results revealed a sex- and tissue-specific role of EST in HS-induced ALI. Pharmacological inhibition of EST may represent an effective approach to manage HS-induced ALI.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1210/endocr/bqz031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6970454PMC
January 2020

Estradiol and selective estrogen receptor agonists differentially affect brain monoamines and amino acids levels in transitional and surgical menopausal rat models.

Mol Cell Endocrinol 2019 10 5;496:110533. Epub 2019 Aug 5.

Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, 15261, USA. Electronic address:

Estrogens have many beneficial effects in the brain. Previously, we evaluated the effects of two models of menopause (surgical vs. transitional) on multiple monoaminergic endpoints in different regions of the adult rat brain in comparison with levels in gonadally intact rats. Here we evaluated the effects of estrogen receptor (ER) agonist treatments in these same two models of menopause. Neurochemical endpoints were evaluated in the hippocampus (HPC), frontal cortex (FCX), and striatum (STR) of adult ovariectomized (OVX) rats and in rats that underwent selective and gradual ovarian follicle depletion by daily injection of 4-vinylcyclohexene-diepoxide (VCD), after 1- and 6-weeks treatment with 17β-estradiol (E2), or with selective ERα (PPT), ERβ (DPN), or GPR30 (G-1) agonists. Endpoints included serotonin (5-HT) and 5-Hydroxyindoleacetic acid, dopamine (DA), 3,4-Dihydroxyphenylacetic acid and homovanillic acid, norepinephrine (NE) and epinephrine, as well as the amino acids tryptophan (TRP) and tyrosine (TYR). Significant differences between the models were detected. OVX rats were much more sensitive to ER agonist treatments than VCD-treated rats. Significant differences between brain regions also were detected. Within OVX rats, more agonist effects were detected in the HPC than in any other region. One interesting finding was the substantial decrease in TRP and TYR detected in the HPC and FCX in response to agonist treatments, particularly in OVX rats. This is on top of the substantial decreases in TRP and TYR previously reported one week after OVX or VCD-treatments in comparison with gonadally intact controls. Other interesting findings included increases in the levels of 5-HT, DA, and NE in the HPC of OVX rats treated with DPN, increases in DA detected in the FCX of OVX rats treated with any of the ER agonists, and increases in 5-HT and DA detected in the STR of OVX rats treated with E2. Many effects that were observed after 1-week of treatment were no longer observed after 6-weeks of treatment, demonstrating that effects were temporary despite continued agonist treatment. Collectively, the results demonstrate significant differences in the effects of ER agonists on monoaminergic endpoints in OVX vs. VCD-treated rats that also were brain region-specific and time dependent. The fact that agonist treatments had lesser effects in VCD treated rats than in OVX rats may help to explain reports of lesser effects of estrogen replacement on cognitive performance in women that have undergone transitional vs. surgical menopause.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mce.2019.110533DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6717664PMC
October 2019

Detection of estradiol in rat brain tissues: Contribution of local versus systemic production.

Psychoneuroendocrinology 2019 04 1;102:84-94. Epub 2018 Dec 1.

Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA. Electronic address:

Estrogens play important roles in regulating brain development, brain function, and behavior. Many studies have evaluated these effects using ovariectomized (OVX) rats or mice with different doses of estrogen replacement, assuming that estradiol levels in all regions of the brain are the same as levels achieved in the serum. It is well known, however, that the brain contains all the enzymes necessary to produce estrogens, and that estrogen levels in the brain are determined by both systemic and local production and are region-specific. The present study conducted a detailed analysis of the relationship between systemic levels of 17-β-estradiol (E2) achieved by estrogen replacement and levels achieved in specific regions of the brain. Levels of E2 were measured in both brain and serum in OVX rats treated with different doses of estradiol benzoate (EB) using a novel and recently validated UPLC-MS/MS method. Results confirmed significantly higher levels of E2 in the brain than in serum in brain regions known to contain aromatase (ARO) activity, both in OVX controls and in rats treated with physiological doses of EB. Additional studies compared the level of E2 and testosterone (T) in the brain and serum between testosterone propionate (TP) treated OVX and male. This demonstrated higher levels of E2 in certain brain regions of males than in TP treated OVX females even though T levels in the brain and serum were similar between the two groups. Studies also demonstrated that the differences between serum and brain levels of E2 can be eliminated by letrozole (ARO inhibitor) treatment, which indicates that the differences are due to local ARO activity. Collectively the results provide a detailed analysis of brain region-specific E2 concentrations in OVX, E2-, and T-treated rats and demonstrate the degree to which these concentrations are ARO-dependent.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.psyneuen.2018.11.037DOI Listing
April 2019

Financial Impact of Minor Injury Transfers on a Level 1 Trauma Center.

J Surg Res 2019 01 18;233:403-407. Epub 2018 Sep 18.

Division of Trauma, Department of Surgery, Cooper University Hospital, Camden, New Jersey.

Background: Trauma centers frequently accept patients from other institutions who are being sent due to the need for a higher level of care. We hypothesized that patients with minor traumatic injuries who are transferred from outside institutions would impart a negative financial impact on the receiving trauma center.

Methods: We performed a retrospective review of all trauma patients admitted to our urban level I trauma center from October 1, 2011, through September 30, 2013. Patients were categorized as minor trauma if they did not require operation within 24 h of arrival, did not require ICU admission, did not die, and had a hospital length of stay <24 h. Transferred patients and nontransfers (those received directly from the field) were compared with respect to injury severity, insurance status, and hospital net margin. Student's t-test and z-test for proportions were performed for data analysis.

Results: A total of 6951 trauma patients were identified (transfer n = 2228, nontransfer n = 4724). Minor injury transfers (n = 440) were compared to nontransfers (n = 689). Hospital net margin of transferred patients and nontransferred patients were $2227 and $2569, respectively (P = 0.22). Percentages of uninsured/underinsured for transfers and nontransfers were 27.3% and 36.1%, respectively (P = 0.002).

Conclusions: During our study period, 19.7% of transfers and 14.6% of nontransfers can be categorized as having minor trauma. Minor trauma transfer patients are associated with a positive hospital net margin for the trauma center that is similar to that of the nontransfer group. The data also demonstrate a lower percentage of uninsured/underinsured in the transferred group.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jss.2018.08.036DOI Listing
January 2019

Effects of Cholinergic Lesions and Cholinesterase Inhibitors on Aromatase and Estrogen Receptor Expression in Different Regions of the Rat Brain.

Neuroscience 2018 08 29;384:203-213. Epub 2018 May 29.

Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA. Electronic address:

Cholinergic projections have been shown to interact with estrogens in ways that influence synaptic plasticity and cognitive performance. The mechanisms are not well understood. The goal of this study was to investigate whether cholinergic projections influence brain estrogen production by affecting aromatase (ARO), or influence estrogen signaling by affecting estrogen receptor expression. In the first experiment, ovariectomized rats received intraseptal injection of the selective immunotoxin 192IgG-saporin to destroy cholinergic inputs to the hippocampus. In the second experiment ovariectomized rats received daily intraperitoneal injections of the cholinesterase inhibitors donepezil or galantamine for 1 week. ARO activity and relative levels of ARO, ERα, ERß, and GPR30 mRNAs were quantified in the hippocampus, frontal cortex, amygdala and preoptic area. Results show that the cholinergic lesions effectively removed cholinergic inputs to the hippocampus, but had no significant effect on ARO or on relative levels of ER mRNAs. Likewise, injections of the cholinesterase inhibitors had no effect on ARO or ER expression in most regions of the brain. This suggests that effects of cholinergic inputs on synaptic plasticity and neuronal function are not mediated by effects on local estrogen production or ER expression. One exception was the amygdala where treating with galantamine was associated with a significant increase in ARO activity. The amygdala is a key structure involved in registering fear and anxiety. Hence this finding may be clinically relevant to elderly patients who are treated for memory impairment and who also struggle with fear and anxiety disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neuroscience.2018.05.033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7646538PMC
August 2018

Comparison of transitional vs surgical menopause on monoamine and amino acid levels in the rat brain.

Mol Cell Endocrinol 2018 11 5;476:139-147. Epub 2018 May 5.

Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, 15261, USA. Electronic address:

Loss of ovarian function has important effects on neurotransmitter production and release with corresponding effects on cognitive performance. To date, there has been little direct comparison of the effects of surgical and transitional menopause on neurotransmitter pathways in the brain. In this study, effects on monoamines, monoamine metabolites, and the amino acids tryptophan (TRP) and tyrosine (TYR) were evaluated in adult ovariectomized (OVX) rats and in rats that underwent selective and gradual ovarian follicle depletion by daily injection of 4-vinylcyclohexene-diepoxide (VCD). Tissues from the hippocampus (HPC), frontal cortex (FCX), and striatum (STR) were dissected and analyzed at 1- and 6-weeks following OVX or VCD treatments. Tissues from gonadally intact rats were collected at proestrus and diestrus to represent neurochemical levels during natural states of high and low estrogens. In gonadally intact rats, higher levels of serotonin (5-HT) were detected at proestrus than at diestrus in the FCX. In addition, the ratio of 5-hydroxyindoleacetic acid (5-HIAA)/5HT in the FCX and HPC was lower at proestrus than at diestrus, suggesting an effect on 5-HT turnover in these regions. No other significant differences between proestrus and diestrus were observed. In OVX- and VCD-treated rats, changes were observed which were both brain region- and time point-dependent. In the HPC levels of norepinephrine, 5-HIAA, TRP and TYR were significantly reduced at 1 week, but not 6 weeks, in both OVX and VCD-treated rats relative to proestrus and diestrus. In the FCX, dopamine levels were elevated at 6 weeks after OVX relative to diestrus. A similar trend was observed at 1 week (but not 6 weeks) following VCD treatment. In the STR, norepinephrine levels were elevated at 1 week following OVX, and HVA levels were elevated at 1 week, but not 6 weeks, following VCD treatment, relative to proestrus and diestrus. Collectively, these data provide the first comprehensive analysis comparing the effects of two models of menopause on multiple neuroendocrine endpoints in the brain. These effects likely contribute to effects of surgical and transitional menopause on brain function and cognitive performance that have been reported.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mce.2018.05.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6120792PMC
November 2018

Comparison between Modelled and Measured Magnetic Field Scans of Different Planar Coil Topologies for Stress Sensor Applications.

Sensors (Basel) 2018 Mar 21;18(4). Epub 2018 Mar 21.

Cardiff School of Engineering, Cardiff University, Queen's Buildings, Cardiff CF24 3AA, UK.

The investigation of planar coils of differing topologies, when combined with a magnetostrictive amorphous ribbon to form a stress-sensitive self-inductor, is an active research area for applications as stress or pressure sensors. Four topologies of planar coil (Circular, Mesh, Meander, and Square) have been constructed using copper track on 30 mm wide PCB substrate. The coils are energized to draw 0.4 A and the resulting magnetic field distribution is observed with a newly developed three-dimensional magnetic field scanner. The system is based on a variably angled Micromagnetics STJ-020 tunneling magneto-resistance sensor with a spatial resolution of 5-10 µm and sensitivity to fields of less than 10 A/m. These experimental results are compared with the fields computed by ANSYS Maxwell finite element modelling of the same topologies. Measured field shape and strength correspond well with the results of modelling, including direct observation of corner and edge effects. Three-dimensional analysis of the field shape produced by the square coil, isolating the components and , is compared with the three-dimensional field solutions from modelling. The finite element modelling is validated and the accuracy and utility of the new system for three-dimensional scanning of general stray fields is confirmed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/s18040931DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5948503PMC
March 2018

Pigment analysis by Raman microscopy and portable X-ray fluorescence (pXRF) of thirteenth to fourteenth century illuminations and cuttings from Bologna.

Philos Trans A Math Phys Eng Sci 2016 Dec;374(2082)

History of Art, University of Glasgow, 8 University Gardens, Glasgow G12 8QQ, UK.

Non-destructive pigment analysis by Raman microscopy (RM) and portable X-ray fluorescence (pXRF) has been carried out on some Bolognese illuminations and cuttings chosen to represent the beginnings, evolution and height of Bolognese illuminated manuscript production. Dating to the thirteenth and fourteenth centuries and held in a private collection, the study provides evidence for the pigments generally used in this period. The results, which are compared with those obtained for other north Italian artwork, show the developments in usage of artistic materials and technique. Also addressed in this study is an examination of the respective roles of RM and pXRF analysis in this area of technical art history.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1098/rsta.2016.0043DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5095523PMC
December 2016

A microsomal based method to detect aromatase activity in different brain regions of the rat using ultra performance liquid chromatography-mass spectrometry.

J Steroid Biochem Mol Biol 2016 10 22;163:113-20. Epub 2016 Apr 22.

Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA. Electronic address:

Aromatase (ARO) is a cytochrome P450 enzyme that accounts for local estrogen production in the brain. The goal of this study was to develop a microsomal based assay to sensitively and reliably detect the low levels of ARO activity in different brain regions. Enzyme activity was detected based on the conversion of testosterone to estradiol. Quantity of estradiol was measured using ultra performance liquid chromatography-mass spectrometry. Detection was linear over a range of 2.5-200pg/ml estradiol, and was reproducible with intra- and inter-assay coefficients of variation (CV) <15%. Estradiol production using isolated microsomes was linear with time up to 30min as well as linearly related to amount of microsome. Substrate concentration curves revealed enzymatic kinetics (hippocampus: Vmax and Km: 0.57pmol estradiol/h per mg microsome and 48.58nM; amygdala: Vmax and Km: 1.69pmol estradiol/h per mg microsome and 48.4nM; preoptic area: Vmax and Km: 0.96pmol estradiol/h per mg microsome and 44.31nM) with testosterone used at a saturating concentration of 400nM. Anastrozole treatment blocked ARO activity in hippocampal and ovarian microsomes, indicating that the assay is specific for ARO. Also, we showed that the distribution of the long form ARO mRNA (CYP19A1) in different regions of the brain is correlated with ARO activity, with highest levels in the amygdala, followed by preoptic area and hippocampus. In the frontal cortex, very little long form ARO mRNA, and little to no ARO activity, were detected. These findings demonstrate that the microsomal incubation (MIB) assay is a sensitive and reliable method for quantifying ARO activity in discrete brain regions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jsbmb.2016.04.013DOI Listing
October 2016

Exome screening to identify loss-of-function mutations in the rhesus macaque for development of preclinical models of human disease.

BMC Genomics 2016 Mar 2;17:170. Epub 2016 Mar 2.

Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, 68198-5805, Nebraska.

Background: Exome sequencing has been utilized to identify genetic variants associated with disease in humans. Identification of loss-of-function mutations with exome sequencing in rhesus macaques (Macaca mulatta) could lead to valuable animal models of genetic disease. Attempts have been made to identify variants in rhesus macaques by aligning exome data against the rheMac2 draft genome. However, such efforts have been impaired due to the incompleteness and annotation errors associated with rheMac2. We wished to determine whether aligning exome reads against our new, improved rhesus genome, MacaM, could be used to identify high impact, loss-of-function mutations in rhesus macaques that would be relevant to human disease.

Results: We compared alignments of exome reads from four rhesus macaques, the reference animal and three unrelated animals, against rheMac2 and MacaM. Substantially more reads aligned against MacaM than rheMac2. We followed the Broad Institute's Best Practice guidelines for variant discovery which utilizes the Genome Analysis Toolkit to identify high impact mutations. When rheMac2 was used as the reference genome, a large number of apparent false positives were identified. When MacaM was used as the reference genome, the number of false positives was greatly reduced. After examining the variant analyses conducted with MacaM as reference genome, we identified two putative loss-of-function mutations, in the heterozygous state, in genes related to human health. Sanger sequencing confirmed the presence of these mutations. We followed the transmission of one of these mutations (in the butyrylthiocholine gene) through three generations of rhesus macaques. Further, we demonstrated a functional decrease in butyrylthiocholinesterase activity similar to that observed in human heterozygotes with loss-of-function mutations in the same gene.

Conclusions: The new MacaM genome can be effectively utilized to identify loss-of-function mutations in rhesus macaques without generating a high level of false positives. In some cases, heterozygotes may be immediately useful as models of human disease. For diseases where homozygous mutants are needed, directed breeding of loss-of-function heterozygous animals could be used to create rhesus macaque models of human genetic disease. The approach we describe here could be applied to other mammals, but only if their genomes have been improved beyond draft status.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12864-016-2509-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4776415PMC
March 2016

A new rhesus macaque assembly and annotation for next-generation sequencing analyses.

Biol Direct 2014 Oct 14;9(1):20. Epub 2014 Oct 14.

Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA.

Background: The rhesus macaque (Macaca mulatta) is a key species for advancing biomedical research. Like all draft mammalian genomes, the draft rhesus assembly (rheMac2) has gaps, sequencing errors and misassemblies that have prevented automated annotation pipelines from functioning correctly. Another rhesus macaque assembly, CR_1.0, is also available but is substantially more fragmented than rheMac2 with smaller contigs and scaffolds. Annotations for these two assemblies are limited in completeness and accuracy. High quality assembly and annotation files are required for a wide range of studies including expression, genetic and evolutionary analyses.

Results: We report a new de novo assembly of the rhesus macaque genome (MacaM) that incorporates both the original Sanger sequences used to assemble rheMac2 and new Illumina sequences from the same animal. MacaM has a weighted average (N50) contig size of 64 kilobases, more than twice the size of the rheMac2 assembly and almost five times the size of the CR_1.0 assembly. The MacaM chromosome assembly incorporates information from previously unutilized mapping data and preliminary annotation of scaffolds. Independent assessment of the assemblies using Ion Torrent read alignments indicates that MacaM is more complete and accurate than rheMac2 and CR_1.0. We assembled messenger RNA sequences from several rhesus tissues into transcripts which allowed us to identify a total of 11,712 complete proteins representing 9,524 distinct genes. Using a combination of our assembled rhesus macaque transcripts and human transcripts, we annotated 18,757 transcripts and 16,050 genes with complete coding sequences in the MacaM assembly. Further, we demonstrate that the new annotations provide greatly improved accuracy as compared to the current annotations of rheMac2. Finally, we show that the MacaM genome provides an accurate resource for alignment of reads produced by RNA sequence expression studies.

Conclusions: The MacaM assembly and annotation files provide a substantially more complete and accurate representation of the rhesus macaque genome than rheMac2 or CR_1.0 and will serve as an important resource for investigators conducting next-generation sequencing studies with nonhuman primates.

Reviewers: This article was reviewed by Dr. Lutz Walter, Dr. Soojin Yi and Dr. Kateryna Makova.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1745-6150-9-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4214606PMC
October 2014

Targeted delivery of Doxorubicin by folic acid-decorated dual functional nanocarrier.

Mol Pharm 2014 Nov 29;11(11):4164-78. Epub 2014 Sep 29.

Center for Pharmacogenetics, ‡Department of Pharmaceutical Sciences, School of Pharmacy, and §University of Pittsburgh Cancer Institute, University of Pittsburgh , Pittsburgh, Pennsylvania 15261, United States.

Doxorubicin (DOX) is one of the most commonly used antineoplastic agents, but its clinical application is oftentimes coupled with severe side effects. Selective delivery of DOX to tumors via nanosized drug carrier represents an attractive approach to this problem. Previously, we developed a dual functional nanomicellar carrier, PEG5K-embelin2 (PEG5K-EB2), which was able to deliver paclitaxel (PTX) selectively to tumors and to achieve an enhanced therapeutic effect. In the present study, we examined the utility of PEG5K-EB2 to deliver DOX to tumors. In addition, folic acid (FA) was coupled to the surface of the PEG5K-EB2 micelles (FA-PEG5K-EB2) to further improve the selective targetability of the system. DOX-loaded PEG5K-EB2 micelles were uniformly spherical particles with a diameter of approximately 20 nm. Incorporation of FA had minimal effect on the size of the particles. The DOX loading efficiency was as high as 91.7% and 93.5% for PEG5K-EB2 and FA-PEG5K-EB2, respectively. DOX formulated in PEG5K-EB2 micelles (with or without FA decoration) demonstrated sustained kinetics of DOX release compared to free DOX. FA-PEG5K-EB2 significantly facilitated the intracellular uptake of DOX over free DOX and PEGylated liposomal DOX (Doxil) in breast cancer cells, 4T1.2, and drug resistant cells, NCI/ADR-RES. P-gp ATPase assay showed that PEG5K-EB2 significantly inhibited the function of the P-gp efflux pump. The maximum tolerated dose of DOX-loaded PEG5K-EB2 micelles was 15 mg/kg in mice, which was 1.5-fold greater than that for free DOX. Pharmacokinetics (PK) and biodistribution studies showed that both types of DOX-loaded micelles, especially FA-PEG5K-EB2, were able to significantly prolong the blood circulation time of DOX and facilitate its preferential accumulation at the tumor tissue. Finally, DOX/PEG5K-EB2 mixed micelles demonstrated significantly enhanced tumor growth inhibitory effect with minimal toxicity in comparison to free DOX and Doxil and the antitumor activity was further enhanced after the decoration by folic acid. Our data suggest that FA-PEG5K-EB2 micelles represent a promising DOX delivery system that warrants more study in the future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/mp500389vDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4224520PMC
November 2014

De novo assembly of the common marmoset transcriptome from NextGen mRNA sequences.

Gigascience 2014 19;3:14. Epub 2014 Sep 19.

Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA.

Background: Nonhuman primates are important for both biomedical studies and understanding human evolution. Although research in these areas has mostly focused on Old World primates, such as the rhesus macaque, the common marmoset (Callithrix jacchus), a New World primate, offers important advantages in comparison to other primates, such as an accelerated lifespan. To conduct Next Generation expression studies or to study primate evolution, a high quality annotation of the marmoset genome is required. The availability of marmoset transcriptome data from five tissues, including both raw sequences and assembled transcripts, will aid in the annotation of the newly released marmoset assembly.

Findings: RNA WAS EXTRACTED FROM FIVE TISSUES: skeletal muscle, bladder and hippocampus from a male common marmoset, and cerebral cortex and cerebellum from a female common marmoset. All five RNA samples were sequenced on the Illumina HiSeq 2000 platform. Sequences were deposited in the NCBI Sequence Read Archive. Transcripts were assembled, annotated and deposited in the NCBI Transcriptome Shotgun Assembly database.

Conclusions: We have provided a high quality annotation of 51,163 transcripts with full-length coding sequence. This set represented a total of 10,833 unique genes. In addition to providing empirical support for the existence of these 10,833 genes, we also provide sequence information for 2,422 genes that were not previously identified in the Ensembl annotation of the marmoset genome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/2047-217X-3-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4169894PMC
September 2014

Estrogen sulfotransferase/SULT1E1 promotes human adipogenesis.

Mol Cell Biol 2014 May 24;34(9):1682-94. Epub 2014 Feb 24.

Center for Pharmacogenetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.

Estrogen sulfotransferase (EST/SULT1E1) is known to catalyze the sulfoconjugation and deactivation of estrogens. The goal of this study is to determine whether and how EST plays a role in human adipogenesis. By using human primary adipose-derived stem cells (ASCs) and whole-fat tissues from the abdominal subcutaneous fat of obese and nonobese subjects, we showed that the expression of EST was low in preadipocytes but increased upon differentiation. Overexpression and knockdown of EST in ASCs promoted and inhibited differentiation, respectively. The proadipogenic activity of EST in humans was opposite to the antiadipogenic effect of the same enzyme in rodents. Mechanistically, EST promoted adipogenesis by deactivating estrogens. The proadipogenic effect of EST can be recapitulated by using an estrogen receptor (ER) antagonist or ERα knockdown. In contrast, activation of ER in ASCs inhibited adipogenesis by decreasing the recruitment of the adipogenic peroxisome proliferator-activated receptor γ (PPARγ) onto its target gene promoters, whereas ER antagonism increased the recruitment of PPARγ to its target gene promoters. Linear regression analysis revealed a positive correlation between the expression of EST and body mass index (BMI), as well as a negative correlation between ERα expression and BMI. We conclude that EST is a proadipogenic factor which may serve as a druggable target to inhibit the turnover and accumulation of adipocytes in obese patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/MCB.01147-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3993609PMC
May 2014

The decline in pulsatile GnRH release, as reflected by circulating LH concentrations, during the infant-juvenile transition in the agonadal male rhesus monkey (Macaca mulatta) is associated with a reduction in kisspeptin content of KNDy neurons of the arcuate nucleus in the hypothalamus.

Endocrinology 2013 May 22;154(5):1845-53. Epub 2013 Mar 22.

University of Pittsburgh, Department Obstetrics and Gynecology and Reproductive Sciences, Magee-Womens Research Institute, 204 Craft Avenue, Pittsburgh, Pennsylvania 15213, USA.

Puberty in primates is timed by 2 hypothalamic events: during late infancy a decline in pulsatile GnRH release occurs, leading to a hypogonadotropic state that maintains quiescence of the prepubertal gonad; and in late juvenile development, pulsatile GnRH release is reactivated and puberty initiated, a phase of development that is dependent on kisspeptin signaling. In the present study, we determined whether the arrest of GnRH pulsatility in infancy was associated with a change in kisspeptin expression in the mediobasal hypothalamus (MBH). Kisspeptin was determined using immunohistochemistry in coronal hypothalamic sections from agonadal male rhesus monkeys during early infancy when GnRH release as reflected by circulating LH concentrations was robust and compared with that in juveniles in which GnRH pulsatility was arrested. The distribution of immunopositive kisspeptin neurons in the arcuate nucleus of the MBH of infants was similar to that previously reported for adults. Kisspeptin cell body number was greater in infants compared with juveniles, and at the middle to posterior level of the arcuate nucleus, this developmental difference was statistically significant. Neurokinin B in the MBH exhibited a similar distribution to that of kisspeptin and was colocalized with kisspeptin in approximately 60% of kisspeptin perikarya at both developmental stages. Intensity of GnRH fiber staining in the median eminence was robust at both stages. These findings indicate that the switch that shuts off pulsatile GnRH release during infancy and that guarantees the subsequent quiescence of the prepubertal gonad involves a reduction in a stimulatory kisspeptin tone to the GnRH neuronal network.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1210/en.2012-2154DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3628021PMC
May 2013

Incorporation of a selective sigma-2 receptor ligand enhances uptake of liposomes by multiple cancer cells.

Int J Nanomedicine 2012 13;7:4473-85. Epub 2012 Aug 13.

Center for Pharmacogenetics, University of Pittsburgh School of Pharmacy, Pittsburgh, PA 15261, USA.

Background: The sigma-2 receptor is an attractive target for tumor imaging and targeted therapy because it is overexpressed in multiple types of solid tumors, including prostate cancer, breast cancer, and lung cancer. SV119 is a synthetic small molecule that binds to sigma-2 receptors with high affinity and specificity. This study investigates the utility of SV119 in mediating the selective targeting of liposomal vectors in various types of cancer cells.

Methods: SV119 was covalently linked with polyethylene glycol-dioleyl amido aspartic acid conjugate (PEG-DOA) to generate a novel functional lipid, SV119-PEG-DOA. This lipid was utilized for the preparation of targeted liposomes to enhance their uptake by cancer cells. Liposomes with various SV119 densities (0, 1, 3, and 5 mole%) were prepared and their cellular uptake was investigated in several tumor cell lines. In addition, doxorubicin (DOX) was loaded into the targeted and unmodified liposomes, and the cytotoxic effect on the DU-145 cells was evaluated by MTT assay.

Results: Liposomes with or without SV119-PEG-DOA both have a mean diameter of approximately 90 nm and a neutral charge. The incorporation of SV119-PEG-DOA significantly increased the cellular uptake of liposomes by the DU-145, PC-3, A549, 201T, and MCF-7 tumor cells, which was shown by fluorescence microscopy and the quantitative measurement of fluorescence intensity. In contrast, the incorporation of SV119 did not increase the uptake of liposomes by the normal BEAS-2B cells. In a time course study, the uptake of SV119 liposomes by DU-145 cells was also significantly higher at each time point compared to the unmodified liposomes. Furthermore, the DOX-loaded SV119 liposomes showed significantly higher cytotoxicity to DU-145 cells compared to the DOX-loaded unmodified liposomes.

Conclusion: SV119 liposomes were developed for targeted drug delivery to cancer cells. The targeting efficiency and specificity of SV119 liposomes to cancer cells was demonstrated in vitro. The results of this study suggest that SV119-modified liposomes might be a promising drug carrier for tumor-targeted delivery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2147/IJN.S31981DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3422102PMC
March 2013

Recognition of novel objects and their location in rats with selective cholinergic lesion of the medial septum.

Neurosci Lett 2012 Jan 20;506(2):261-5. Epub 2011 Nov 20.

Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, United States.

The importance of cholinergic neurons projecting from the medial septum (MS) of the basal forebrain to the hippocampus in memory function has been controversial. The aim of this study was to determine whether loss of cholinergic neurons in the MS disrupts object and/or object location recognition in male Sprague-Dawley rats. Animals received intraseptal injections of either vehicle, or the selective cholinergic immunotoxin 192 IgG-saporin (SAP). 14 days later, rats were tested for novel object recognition (NOR). Twenty-four hours later, these same rats were tested for object location recognition (OLR) (recognition of a familiar object moved to a novel location). Intraseptal injections of SAP produced an 86% decrease in choline acetyltransferase (ChAT) activity in the hippocampus, and a 31% decrease in ChAT activity in the frontal cortex. SAP lesion had no significant effect on NOR, but produced a significant impairment in OLR in these same rats. The results support a role for septo-hippocampal cholinergic projections in memory for the location of objects, but not for novel object recognition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neulet.2011.11.019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3462014PMC
January 2012

Core competencies for research training in the clinical pharmaceutical sciences.

Am J Pharm Educ 2011 Mar;75(2):27

University of Pittsburgh, School of Pharmacy, Pittsburgh, PA 15261, USA.

Objective: To identify and apply core competencies for training students enrolled in the clinical pharmaceutical scientist PhD training program at the University of Pittsburgh School of Pharmacy.

Design: Faculty members reached consensus on the required core competencies for the program and mapped them to curricular and experiential requirements.

Assessment: A rubric was created based on core competencies spanning 8 major categories of proficiency, and competencies of clinical versus traditional PhD training were delineated. A retrospective evaluation of the written comprehensive examinations of 12 former students was conducted using the rubric. Students scored above satisfactory in 11 out of 14 comprehensive examination metrics, with a mean score greater than 3.8 on a 5-point scale.

Conclusions: The core competencies identified will provide an essential foundation for informed decision-making and assessment of PhD training in the clinical pharmaceutical sciences.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3073101PMC
http://dx.doi.org/10.5688/ajpe75227DOI Listing
March 2011

Evaluation of a combined therapeutic regimen of 8-OH-DPAT and environmental enrichment after experimental traumatic brain injury.

J Neurotrauma 2010 Nov 28;27(11):2021-32. Epub 2010 Oct 28.

Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.

When provided individually, both the serotonin (5-HT(1A))-receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and environmental enrichment (EE) enhance behavioral outcome and reduce histopathology after experimental traumatic brain injury (TBI). The aim of this study was to determine whether combining these therapies would yield greater benefit than either used alone. Anesthetized adult male rats received a cortical impact or sham injury and then were randomly assigned to enriched or standard (STD) housing, where either 8-OH-DPAT (0.1 mg/kg) or vehicle (1.0 mL/kg) was administered intraperitoneally once daily for 3 weeks. Motor and cognitive assessments were conducted on post-injury days 1-5 and 14-19, respectively. CA1/CA3 neurons and choline acetyltransferase-positive (ChAT(+)) medial septal cells were quantified at 3 weeks. 8-OH-DPAT and EE attenuated CA3 and ChAT(+) cell loss. Both therapies also enhanced motor recovery, acquisition of spatial learning, and memory retention, as verified by reduced times to traverse the beam and to locate an escape platform in the water maze, and a greater percentage of time spent searching in the target quadrant during a probe trial in the TBI + STD + 8-OH-DPAT, TBI + EE + 8-OH-DPAT, and TBI + EE + vehicle groups versus the TBI + STD + vehicle group (p ≤ 0.0016). No statistical distinctions were revealed between the TBI + EE + 8-OH-DPAT and TBI + EE + vehicle groups in functional outcome or CA1/CA3 cell survival, but there were significantly more ChAT(+) cells in the former (p = 0.003). These data suggest that a combined therapeutic regimen of 8-OH-DPAT and EE reduces TBI-induced ChAT(+) cell loss, but does not enhance hippocampal cell survival or neurobehavioral performance beyond that of either treatment alone. The findings underscore the complexity of combinational therapies and of elucidating potential targets for TBI.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/neu.2010.1535DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2978058PMC
November 2010

Does short-term estrogen therapy produce lasting benefits in brain?

Authors:
Robert B Gibbs

Endocrinology 2010 Mar;151(3):843-5

University of Pittsburgh School of Pharmacy, 1004 Salk Hall, Pittsburgh, Pennsylvania 15261, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1210/en.2009-1453DOI Listing
March 2010

Estrogen therapy and cognition: a review of the cholinergic hypothesis.

Authors:
Robert B Gibbs

Endocr Rev 2010 Apr 17;31(2):224-53. Epub 2009 Dec 17.

University of Pittsburgh School of Pharmacy, 1004 Salk Hall, Pittsburgh, Pennsylvania 15261, USA.

The pros and cons of estrogen therapy for use in postmenopausal women continue to be a major topic of debate in women's health. Much of this debate focuses on the potential benefits vs. harm of estrogen therapy on the brain and the risks for cognitive impairment associated with aging and Alzheimer's disease. Many animal and human studies suggest that estrogens can have significant beneficial effects on brain aging and cognition and reduce the risk of Alzheimer's-related dementia; however, others disagree. Important discoveries have been made, and hypotheses have emerged that may explain some of the inconsistencies. This review focuses on the cholinergic hypothesis, specifically on evidence that beneficial effects of estrogens on brain aging and cognition are related to interactions with cholinergic projections emanating from the basal forebrain. These cholinergic projections play an important role in learning and attentional processes, and their function is known to decline with advanced age and in association with Alzheimer's disease. Evidence suggests that many of the effects of estrogens on neuronal plasticity and function and cognitive performance are related to or rely upon interactions with these cholinergic projections; however, studies also suggest that the effectiveness of estrogen therapy decreases with age and time after loss of ovarian function. We propose a model in which deficits in basal forebrain cholinergic function contribute to age-related changes in the response to estrogen therapy. Based on this model, we propose that cholinergic-enhancing drugs, used in combination with an appropriate estrogen-containing drug regimen, may be a viable therapeutic strategy for use in older postmenopausal women with early evidence of mild cognitive decline.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1210/er.2009-0036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2852210PMC
April 2010

Selective lesion of septal cholinergic neurons in rats impairs acquisition of a delayed matching to position T-maze task by delaying the shift from a response to a place strategy.

Brain Res Bull 2008 Dec 20;77(6):356-60. Epub 2008 Sep 20.

Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA.

This study tested the hypothesis that septal cholinergic lesions impair acquisition of a delayed matching to position (DMP) T-maze task in male rats by affecting learning strategy. Rats received either the selective cholinergic immunotoxin, 192 IgG-saporin (SAP) or artificial cerebrospinal fluid directly into the medial septum. Two weeks later, animals were trained to acquire the DMP task. SAP-treated rats took significantly longer to acquire the task than corresponding controls. Both SAP-treated and control rats adopted a persistent turn and utilized a response strategy during early periods of training. By the time rats reached criterion the persistent turn was no longer evident, and all rats had shifted to an allocentric strategy, i.e., were relying on extramaze cues to a significant degree. During the acquisition period, SAP-treated rats spent significantly more days showing a persistent turn and using a response strategy than corresponding controls. The added time spent using a response strategy accounted entirely for the added days required to reach criterion among the SAP-treated rats. This suggests that the principal mechanism by which septal cholinergic lesions impair DMP acquisition in male rats is by increasing the predisposition to use a response vs. a place strategy, thereby affecting the ability to switch from one strategy to another.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.brainresbull.2008.08.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2649660PMC
December 2008

Structural interactions between kisspeptin and GnRH neurons in the mediobasal hypothalamus of the male rhesus monkey (Macaca mulatta) as revealed by double immunofluorescence and confocal microscopy.

Endocrinology 2008 Sep 29;149(9):4387-95. Epub 2008 May 29.

Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.

Kisspeptin is recognized to play a critical role in eliciting the pubertal resurgence of pulsatile GnRH release, the proximal trigger of puberty in higher primates. Expression of the kisspeptin receptor (GPR54) by GnRH neurons indicates a direct action of kisspeptin on the GnRH neuronal network. The purpose of the present study was to examine the distribution of kisspeptin cell bodies in the monkey hypothalamus and to assess the structural basis for the stimulatory action of kisspeptin on the GnRH neuronal network. Three castrated male rhesus monkeys, 39-51 months of age, were deeply anesthetized and their brains perfused transcardially with 4% paraformaldehyde in PBS. Serial 25-microm coronal sections throughout the hypothalamus were prepared, and immunopositive neurons identified using a cocktail of specific primary antibodies (sheep anti-kisspeptin at 1:120,000, and rabbit anti-GnRH at 1:100,000) detected with fluorescently tagged secondary antibodies (antisheep, Alexa Fluor 488; antirabbit, Cy3) in combination with confocal microscopy. Kisspeptin perikarya were found only in the mediobasal hypothalamus (MBH) almost exclusively in the posterior two-thirds of the arcuate nucleus. Surprisingly, kisspeptin-beaded axons made only infrequent contacts with GnRH neurons (kisspeptin and GnRH profiles abutting in a 0.5- to 1.0-mum optical section) in the MBH. In the median eminence, kisspeptin and GnRH axons were found in extensive and intimate association. GnRH contacts on kisspeptin perikarya and dendrites were observed. These findings indicate that nonsynaptic pathways of communication in the median eminence should be considered as a possible mechanism of kisspeptin regulation of GnRH release, and provide an anatomical basis for reciprocal control of kisspeptin neuronal activity by GnRH.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1210/en.2008-0438DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2553371PMC
September 2008

Sex-specific effects of gonadectomy and hormone treatment on acquisition of a 12-arm radial maze task by Sprague Dawley rats.

Endocrinology 2008 Jun 21;149(6):3176-83. Epub 2008 Feb 21.

University of Pittsburgh School of Pharmacy, 1004 Salk Hall, Pittsburgh, Pennsylvania 15261, USA.

The effects of gonadectomy and hormone treatment on spatial learning were evaluated in adult male and female rats using a modified version of a 12-arm radial maze task. In this version, procedures were used to minimize the effectiveness of strategies less reliant on working and reference memory. Results demonstrate significant sex differences favoring male performance on the working memory component of the task. In contrast, females performed slightly better than males on the reference memory component of the task. In females, ovariectomy produced a decrease in overall accuracy (i.e. an increase in the number of arm entries necessary to obtain all food pellets) as well as declines in working and reference memory performance. Both accuracy and working memory performance, but not reference memory performance, were restored by estradiol treatment. In males, castration impaired working memory performance but did not significantly affect overall accuracy or reference memory performance. Surprisingly, all groups of males performed poorly on the reference memory component of the task, and testosterone treatment appeared to worsen, rather than improve, both accuracy and reference memory performance in males. This may reflect a male preference for certain strategies that were rendered ineffective on this task. Significant sex differences, as well as treatment effects, on arm preference patterns were also detected; however, these differences were not sufficient to account for the effects of sex and treatment on acquisition. Collectively, the data demonstrate robust effects of gonadectomy and hormone treatment on acquisition of this modified radial arm maze task in females, with lesser effects in males.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1210/en.2007-1645DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2408814PMC
June 2008

Estradiol enhances DMP acquisition via a mechanism not mediated by turning strategy but which requires intact basal forebrain cholinergic projections.

Authors:
Robert B Gibbs

Horm Behav 2007 Sep 31;52(3):352-9. Epub 2007 May 31.

Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, 1004 Salk Hall, Pittsburgh, PA 15261, USA.

This study examined whether effects on turning strategy, use of an allocentric strategy, and/or short-term spatial memory account for the effects of estradiol treatment on acquisition of a delayed matching-to-position (DMP) T-maze task, in rats with and without basal forebrain cholinergic lesions. Ovariectomized rats received either 192IgG saporin (SAP) or saline injected into the medial septum. Two weeks later, half of each group received either continuous estradiol treatment (5-mm silastic capsule containing 17-beta-estradiol implanted s.c.) or implantation of an empty capsule. All rats were trained on the DMP task. Results show that estradiol enhanced, and SAP lesions impaired, learning on the DMP task. SAP lesions impaired learning primarily by increasing the use of a persistent turning strategy early on during training. In contrast, estradiol had no apparent effect on turning strategy, and enhanced learning only in non-lesioned rats. There was no evidence that any of these effects were due primarily to an effect on ultimate strategy selection (e.g., allocentric vs. egocentric, evaluated with a probe trial in which the maze was rotated 180 degrees), or on short-term spatial memory (evaluated by increasing the intertrial delay). We conclude that estradiol enhances DMP acquisition via a mechanism independent of effects on turning strategy and short-term memory, but nevertheless dependent on cholinergic neurons in the MS and VDB. We hypothesize that estradiol may affect the facility with which female rats are able to extract and incorporate extramaze information into an effective navigational strategy, and that this may be mediated by effects in prefrontal cortex.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.yhbeh.2007.05.011DOI Listing
September 2007

SP1 transcription factors in male germ cell development and differentiation.

Mol Cell Endocrinol 2007 May 12;270(1-2):1-7. Epub 2007 Mar 12.

Department of Anatomy and Neurobiology, Morehouse School of Medicine, Atlanta, GA 30310-1495, United States.

Transcription factor SP1 is a zinc finger protein that has been implicated in regulating the expression of several genes involved in cellular differentiation and embryonic development. The zinc finger region of SP1 transcription factors binds to GC or GT-box elements present in the promoters of a number of male germ cell target genes that are developmentally expressed during spermatogenesis. The glutamine and serine/threonine-rich regions of the SP1 proteins recruit co-regulatory factors to the multi-protein preinitiation complex that are important for mediating transcriptional activation in male germ cells. Studies in our laboratory have identified several alternatively spliced transcripts encoding SP1 isoforms that display stage and cell-type-specific expression profiles in differentiating germ cells in the seminiferous epithelium of the testis. This review summarizes the expression patterns and functional significance of these SP1 transcription factor variants during spermatogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mce.2007.03.001DOI Listing
May 2007

Insulin-like peptide 6: characterization of secretory status and posttranslational modifications.

Endocrinology 2006 Dec 24;147(12):5611-23. Epub 2006 Aug 24.

Department of Pediatrics, University of Michigan, 1205 Medical Professional Building Box 0718, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109-0718, USA.

Insulin-like peptide 6 (Insl6) is a member of the insulin/relaxin superfamily with unknown biological function(s). In the current report, we establish that meiotic and postmeiotic germ cells of the testis are the principal sites of expression of Insl6. Analysis of stably or transiently transfected cells revealed that Insl6 is a secreted protein localized to the endoplasmic reticulum and Golgi. Secretion could be detected in both CHO and GC2 germ cells and was sensitive to brefeldin A treatment. In cell lysates, the predominant Insl6 band was approximately 28 kDa in size. In contrast, the predominant Insl6 species in the supernatant was 8 kDa in size, suggesting posttranslational processing of the precursor protein. Ectopically expressed Insl6 is processed and secreted in furin-deficient LoVo cells and in CHO cells treated with a furin inhibitor, although the size profile of the secreted protein is altered suggesting that Insl6 is a substrate for furin action. Furthermore, mutation of a putative furin cleavage site in the Insl6 peptide resulted in aberrant processing of the Insl6 peptide. Additional investigations of the structure of Insl6 protein provided evidence for posttranslational modifications of Insl6, including the presence of disulfide bonds, glycosylation, and ubiquitination. On the basis of the demonstrated secretory status of Insl6, we speculate that the physical proximity of the germ cell to the Sertoli cell renders the Sertoli cell a likely candidate for Insl6 action.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1210/en.2006-0503DOI Listing
December 2006