Mechanisms of ischaemic neural progenitor proliferation: a regulatory role of the HIF-1α-CBX7 pathway.

AIMS: Investigations of the molecular mechanisms of hypoxia- and ischaemia-induced endogenous neural progenitor cell (NPC) proliferation have mainly focused on factors secreted in response to environmental cues. However, little is known about the intrinsic regulatory machinery underlying the self-renewing division of NPCs in the brain after stroke. METHODS AND RESULTS: Polycomb repressor complex 1-chromobox7 (CBX7) has emerged as a key regulator in several cellular processes including stem cell self-renewal and cancer cell proliferation. The hypoxic environment triggering NPC self-renewal after CBX7 activation remains unknown. In this study, we found that the upregulation of CBX7 during hypoxia and ischaemia appeared to be from hypoxia-inducible factor-1α (HIF-1α) activation. During hypoxia, the HIF-1α-CBX7 cascade modulated NPC proliferation in vitro. NPC numbers significantly decreased in CBX7 knockout mice generated using CRISPR/Cas9 genome editing. CONCLUSIONS: We provided the novel insight that CBX7 expression is regulated through HIF-1α activation, which plays an intrinsically modulating role in NPC proliferation.

Growth of liver allografts over time in pediatric transplant recipients.

The liver's capacity to grow in response to metabolic need is well known. However, long-term growth of liver allografts in pediatric recipients has not been characterized. A retrospective review of pediatric recipients at a single institution identified patients who had cross-sectional imaging at 1, 5, and 10 years post-transplant. Using volumetric calculations, liver allograft size was calculated and percent SLV were compared across the different time points; 18 patients ranging from 0.3 to 17.7 years old were identified that had imaging at 2 or more time points. Measured liver volumes increased by 59% after 5 years and 170% after 10 years. The measured liver volumes compared to calculated %SLV for these patients were 123 ± 37%, 97 ± 19%, and 118 ± 27% at 1, 5, and 10 years after transplant, respectively. Our data suggest that liver allografts in pediatric recipients increase along with overall growth, and reach SLVs for height and weight by 5 years post-transplantation. Additionally, as pediatric recipients grow, the livers appear to maintain appropriate SLV.

Pond sediment magnetite grains show a distinctive microbial community.

Formation of magnetite in anaerobic sediments is thought to be enhanced by the activities of iron-reducing bacteria. Geobacter has been implicated as playing a major role, as in culture its cells are often associated with extracellular magnetite grains. We studied the bacterial community associated with magnetite grains in sediment of a freshwater pond in South Korea. Magnetite was isolated from the sediment using a magnet. The magnetite-depleted fraction of sediment was also taken for comparison. DNA was extracted from each set of samples, followed by PCR for 16S bacterial ribosomal RNA (rRNA) gene and HiSeq sequencing. The bacterial communities of the magnetite-enriched and magnetite-depleted fractions were significantly different. The enrichment of three abundant operational taxonomic units (OTUs) suggests that they may either be dependent upon the magnetite grain environment or may be playing a role in magnetite formation. The most abundant OTU in magnetite-enriched fractions was Geobacter, bolstering the case that this genus is important in magnetite formation in natural systems. Other major OTUs strongly associated with the magnetite-enriched fraction, rather than the magnetite-depleted fraction, include a Sulfuricella and a novel member of the Betaproteobacteria. The existence of distinct bacterial communities associated with particular mineral grain types may also be an example of niche separation and coexistence in sediments and soils, which cannot usually be detected due to difficulties in separating and concentrating minerals.

Increased 8-hydroxy-2'-deoxyguanosine in plasma and decreased mRNA expression of human 8-oxoguanine DNA glycosylase 1, anti-oxidant enzymes, mitochondrial biogenesis-related proteins and glycolytic enzymes in leucocytes in patients with systemic lupus erythematosus.

We measured plasma levels of the oxidative DNA damage marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) and leucocyte mRNA expression levels of the genes encoding the 8-OHdG repair enzyme human 8-oxoguanine DNA glycosylase 1 (hOGG1), the anti-oxidant enzymes copper/zinc superoxide dismutase (Cu/ZnSOD), manganese superoxide dismutase (MnSOD), catalase, glutathione peroxidase-1 (GPx-1), GPx-4, glutathione reductase (GR) and glutathione synthetase (GS), the mitochondrial biogenesis-related proteins mtDNA-encoded ND 1 polypeptide (ND1), ND6, ATPase 6, mitochondrial transcription factor A (Tfam), nuclear respiratory factor 1(NRF-1), pyruvate dehydrogenase E1 component alpha subunit (PDHA1), pyruvate dehydrogenase kinase isoenzyme 1 (PDK-1) and hypoxia inducible factor-1α (HIF-1α) and the glycolytic enzymes hexokinase-II (HK-II), glucose 6-phosphate isomerase (GPI), phosphofructokinase (PFK), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and lactate dehydrogenase A (LDHa). We analysed their relevance to oxidative damage in 85 systemic lupus erythematosus (SLE) patients, four complicated SLE patients undergoing rituximab treatment and 45 healthy individuals. SLE patients had higher plasma 8-OHdG levels (P < 0·01) but lower leucocyte expression of the genes encoding hOGG1(P < 0·01), anti-oxidant enzymes (P < 0·05), mitochondrial biogenesis-related proteins (P < 0·05) and glycolytic enzymes (P < 0·05) than healthy individuals. The increase in plasma 8-OHdG was correlated positively with the elevation of leucocyte expression of the genes encoding hOGG1 (P < 0·05), anti-oxidant enzymes (P < 0·05), several mitochondrial biogenesis-related proteins (P < 0·05) and glycolytic enzymes (P < 0·05) in lupus patients. The patients, whose leucocyte mtDNA harboured D310 heteroplasmy, exhibited a positive correlation between the mtDNA copy number and expression of ND1, ND6 and ATPase 6 (P < 0·05) and a negative correlation between mtDNA copy number and systemic lupus erythematosus disease activity index (SLEDAI) (P < 0·05), as well as plasma 8-OHdG (P < 0·05). In particular, four complicated SLE patients with increased expression of the genes encoding the anti-oxidant enzymes, GAPDH, Tfam and PDHA1, experienced better therapeutic outcomes after rituximab therapy. In conclusion, higher oxidative damage with suboptimal increases in DNA repair, anti-oxidant capacity, mitochondrial biogenesis and glucose metabolism may be implicated in SLE deterioration, and this impairment might be improved by targeted biological therapy.

Effects of serial passage on the characteristics and chondrogenic differentiation of canine umbilical cord matrix derived mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are often known to have a therapeutic potential in the cell-mediated repair for fatal or incurable diseases. In this study, canine umbilical cord MSCs (cUC-MSCs) were isolated from umbilical cord matrix (n = 3) and subjected to proliferative culture for 5 consecutive passages. The cells at each passage were characterized for multipotent MSC properties such as proliferation kinetics, expression patterns of MSC surface markers and self-renewal associated markers, and chondrogenic differentiation. In results, the proliferation of the cells as determined by the cumulative population doubling level was observed at its peak on passage 3 and stopped after passage 5, whereas cell doubling time dramatically increased after passage 4. Expression of MSC surface markers (CD44, CD54, CD61, CD80, CD90 and Flk-1), molecule (HMGA2) and pluripotent markers (sox2, nanog) associated with self-renewal was negatively correlated with the number of passages. However, MSC surface marker (CD105) and pluripotent marker (Oct3/4) decreased with increasing the number of subpassage. cUC-MSCs at passage 1 to 5 underwent chondrogenesis under specific culture conditions, but percentage of chondrogenic differentiation decreased with increasing the number of subpassage. Collectively, the present study suggested that sequential subpassage could affect multipotent properties of cUC-MSCs and needs to be addressed before clinical applications.

Comparative analysis of virulence factors secreted by Bacillus anthracis Sterne at host body temperature.

AIMS: For the analysis of virulence factors produced and secreted by Bacillus anthracis vegetative cells during mammalian host infection, we evaluated the secretome of B. anthracis Sterne exposed to host-specific factors specifically to host body temperature. METHODS AND RESULTS: We employed a comparative proteomics-based approach to analyse the proteins secreted by B. anthracis Sterne under host-specific body temperature conditions. A total of 17 proteins encoded on a single chromosome and the pXO1 plasmid were identified by peptide mass fingerprinting. Multiple algorithms were used to predict the secretion mechanisms of the detected proteins in B. anthracis. CONCLUSIONS: Several putative virulence factors and known factors responsible for sporulation were differentially regulated, including CodY, pXO1-130 and BA1952, revealing insights into temperature cues in the B. anthracis secretome. SIGNIFICANCE AND IMPACT OF THE STUDY: This study identified temperature-regulated proteins. Further studies aimed at understanding the physical and functional roles of these proteins in infection and control by elevated temperatures will contribute to detection, diagnostics and prophylaxis.

Hypothermic machine preservation in human liver transplantation: the first clinical series.

Hypothermic machine perfusion (HMP) is widely used to preserve kidneys for transplantation with improved results over cold storage (CS). To date, successful transplantation of livers preserved with HMP has been reported only in animal models. In this, the first prospective liver HMP study, 20 adults received HMP-preserved livers and were compared to a matched group transplanted with CS livers. HMP was performed for 3-7 h using centrifugal perfusion with Vasosol solution at 4-6 degrees C. There were no cases of primary nonfunction in either group. Early allograft dysfunction rates were 5% in the HMP group versus 25% in controls (p = 0.08). At 12 months, there were two deaths in each group, all unrelated to preservation or graft function. There were no vascular complications in HMP livers. Two biliary complications were observed in HMP livers compared with four in the CS group. Serum injury markers were significantly lower in the HMP group. Mean hospital stay was shorter in the HMP group (10.9 +/- 4.7 days vs. 15.3 +/- 4.9 days in the CS group, p = 0.006). HMP of donor livers provided safe and reliable preservation in this pilot case-controlled series. Further multicenter HMP trials are now warranted.

Simple and comprehensive SLA-DQB1 genotyping using genomic PCR and direct sequencing.

To enable the efficient analysis of a highly polymorphic swine major histocompatibility complex (MHC) class II gene, swine leukocyte antigen (SLA)-DQB1, we developed a simple and comprehensive high-resolution genotyping protocol. To obtain sufficient sequence information to design a set of common genotyping primers for SLA-DQB1, we cloned SLA-DQB1 introns 1 and 2 from 11 alleles with official four-digit allelic designations and sequenced the regions directly surrounding the SLA-DQB1 exon 2. Significant intronic nucleotide variations, including several deletions, were identified. Based on 733-bp assembled genomic sequences including introns 1 and 2 and exon 2 from 11 different alleles, a primer set was identified that allowed the ubiquitous amplification and analysis of the complete SLA-DQB1 exon 2 sequence. We then developed a method to directly sequence the amplified polymerase chain reaction (PCR) products without further experimental steps. We especially focused on avoiding superimposed peaks, which arose from the presence of allelic deletions, in the sequencing electropherogram of SLA-DQB1 heterozygous animals. The genotyping accuracy was evaluated by comparing the results of genomic sequence-based typing (GSBT) with those of other available methods, including cDNA sequence-based typing (SBT), low-resolution PCR typing with sequence-specific primers, allelic segregation analysis, and heterozygote simulation typing. In all cases, the results were consistent between SLA-DQB1 GSBT and previously reported methods or expected results. We applied it to genotype 350 animals from seven pig breeds. The observed level of heterozygosity from our genotyping was ∼51%, reflecting that a large portion of the animals were inbred miniature pigs. Among the seven pig breeds tested, the allelic diversity of SLA-DQB1 was highest in Berkshire pigs. In conclusion, we have developed a simple and effective SLA-DQB1 GSBT method by combining simple genomic DNA PCR and direct sequencing. Our new method may aid in the study of SLA diversity and disease resistance and susceptibility.

Changes in hepatic lipid parameters and hepatic messenger ribonucleic acid expression following estradiol administration in laying hens (Gallus domesticus).

Fatty liver hemorrhagic syndrome (FLHS) is characterized by increased hepatic triacylglycerol content associated with liver hemorrhages and results in a sudden decline in egg production. Genetic, environmental, nutritional, and hormonal factors have all been implicated in the etiology of FLHS, but the exact cause of FLHS is still unknown. Estrogens have been implicated in the development of excess fat content of the liver and in the etiology of FLHS. This study investigated estradiol (E(2)) administration in hens and its effect on lipid metabolism. Hy-Line Brown laying hens were intramuscularly injected with E(2) on a daily basis for 3 wk. The dosages were 0, 0.5, and 1.0 mg/kg of BW, with corn oil injections used as a control. Egg production and quality were measured among the groups, with no significant difference seen in egg production. Liver weights of hens treated with E(2) were greater than those of control hens, but the increase was not statistically significant. Serum glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase activities and E(2) plasma concentrations increased in a dose-dependent manner, with plasma concentration of E(2) increasing from 6,900 to 19,000 pg/mL. No significant differences in free cholesterol or phospholipids were observed, but there was a significant increase in hepatic triacylglycerol levels. Injection with E(2) showed an increased expression of mRNA for peroxisome proliferator-activated receptor γ (23-fold), but not for peroxisome proliferator-activated receptor α. A statistically significant increase was seen for fatty acid synthase, apolipoprotein B, and adenosine triphosphate citrate lyase, but not for acetyl coenzyme A carboxylase, apolipoprotein VLDL-II, microsomal triglyceride transport protein, or malic enzyme. For proteins involved in the oxidation of E(2), only cytochrome P450 3A37 showed a statistically significant increase. The present results suggest that E(2) upregulates the synthesis of fatty acids and triacylglycerols and the accumulation of hepatic lipids by increasing mRNA expression related to lipid metabolism, and that excess E(2) in the blood leads to activation of E(2) catabolic metabolism (cytochrome P450 3A37)-related mRNA expression.

Effect of transgene introduction and recloning on efficiency of porcine transgenic cloned embryo production in vitro.

Retrovirus-mediated exogenous gene transfection of somatic cells is an efficient method to produce transgenic embryos by somatic cell nuclear transfer (SCNT). This study evaluated whether efficiency of transgenic embryos production, by SCNT using fibroblast cells transfected by retrovirus vector, is influenced by the introduced transgene and whether recloning could further improve its efficiency. Transgenic cloned embryos were produced by SCNT of porcine foetal fibroblast cells transfected by either LNbeta-Z or LNbeta-enhanced green fluorescent protein (EGFP) retrovirus vector and evaluated for their developmental ability in vitro. Blastomeres from four-cell stage porcine embryos, produced by SCNT of foetal fibroblast cells transfected with LNbeta-EGFP retroviral vector, were subsequently recloned into enucleated metaphase II oocytes and evaluated for changes in chromatin configuration, in vitro embryo development and gene expression. Analysis of results showed that cleavage and blastocyst rates of porcine SCNT embryos, using LacZ (53.6 +/- 6.4%; 12.0 +/- 5.7%) or EGFP (57.5 +/- 6.3%; 10.1 +/- 4.1%) transfected fibroblasts, did not differ (p > 0.05) from those of non-transfected controls (60.9 +/- 8.2%; 12.3 +/- 4.0%). Recloning of blastomeres did not further improve the in vitro development rate. Interestingly, the nuclei of blastomere underwent slower remodelling process than somatic cell nuclei. Both cloned and recloned embryos showed 100% transgene expression and there were no evidence of mosaicism. In conclusion, our data shows that the efficiency of transgenic cloned embryos production by SCNT of somatic cells transfected with replication-defective retrovirus vector is not influenced by the transgene introduction into donor cells and recloning of four-cell stage blastomere could not further improve its efficiency.

Reporting 678 putative cSNPs from full-length enriched cDNA sequences of the Korean native pig.

Sequences from the clones of full-length enriched cDNA libraries serve as valuable resources for functional genomic studies. We have analysed 1970 high-quality chromatograms (Phred value >or= 30) that were obtained from sequencing the 5' ends of brainstem, liver, neocortex and spleen clones derived from full-length enriched cDNA libraries from Korean native pigs. In addition, 50,000 pig expressed sequence tag (EST) sequence trace files were obtained from Genbank and combined with our sequencing information to facilitate SNP identification in silico. The process generated 8118 contigs, of which 239 included minimum one sequence from Korean native pig and contained 678 putative coding single nucleotide polymorphisms (cSNPs). Of these, 33 putative cSNPs were randomly selected for confirmatory analysis and validated using 20 pigs from four different breeds (Duroc, Landrace, Yorkshire, Korean native pig). Of the 33 putative cSNPs, 20 were confirmed (61%), which was similar to the frequency reported in other studies. We also identified 15 new cSNPs from the validation process, which were not detected by our in silico analysis. Our study shows that analysing genetically diverse pig breeds including the Korean native pig could serve as a useful strategy for generating a large number of cSNPs.

beta-Adrenoceptor blockers protect against staurosporine-induced apoptosis in SH-SY5Y neuroblastoma cells.

The beta-adrenoceptor blockers exhibit a well-characterized anti-apoptotic property in the heart and kidney while less is known about the effect of this class of drugs on neuronal apoptosis. We studied the effects of three beta-adrenoceptor blockers propranolol (1-(isoproplyamino)-3-(naphthalene-1-yloxy)propan-2-ol), atenolol (2-[4-[2-hydroxy-3-(1-methylethylamino)propoxyl]phenyl]ehanamide), and ICI 118551 (1-[2,3-(dihydro-7-methyl-1H-iden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol), against staurosporine-induced apoptosis in SH-SY5Y human neuroblastoma cells. Staurosporine increased caspase 3-like activity, DNA fragmentation, PARP cleavage, and the number of TUNEL positive cells consistent with the induction of apoptosis. Propranolol and ICI 118551, but not atenolol, demonstrated a concentration-dependent inhibition of caspase 3-like activity. Propranolol and ICI 118551 directly inhibited the enzymatic activity of recombinant caspase 9 while atenolol did not; however, none of the beta-adrenoceptor blockers that were examined directly blocked caspases 2 or 3 activity. In isolated mitochondria, propranolol and ICI 118551 inhibited staurosporine-induced cytochrome c release while atenolol did not. We conclude that propranolol and ICI 118551 protect SH-SY5Y cells against staurosporine-induced apoptosis through a dual action on the mitochondria and on caspase 9 in a cell type and an apoptotic paradigm where the conventional inhibitors of mitochondrial permeability transition such as cyclosporin A and bongkrekic acid demonstrate no protection.

Transmissible infection of human 293T cells with porcine endogenous retroviruses subgroup a from NIH-miniature pig.

In pig-to-human xenotransplantation, zoonotic infections have been an important barrier. The risk of zoonosis has been emphasized in xenotransplantation after finding that porcine endogenous retroviruses (PERVs) can infect human cells in vitro. Until now, transmissions of PERVs from PK15 cells have been studied in vitro and in vivo, but transmission of PERVs originating from miniature pigs have not been extensively reported. Peripheral blood mononuclear cells from miniature swine showed PERV transmission to human cells. In contrast, specific pathogen-free (SPF) pig islet cells showed no PERV transmission when co-incubated with 293T cells. To evaluate the risk of zoonosis with our experimental mini pigs, we tested the infectivity of PERVs from NIH-miniature pig primary ear cells for human 293T cells. As a result, all subgroups of infectious PERV virion (PERV-A, -B, and -C) were detected in the primary cell culture media. Unlike PERV-C, PERV-A and -B infected human 293T cells. Interestingly, only proviral PERV-A replicated in 293T cells to produce virions after infection. Our results suggested that a prevention study of PERV xenotransmission from experimental miniature pigs should concentrate on PERV-A control.

Development of transgenic chickens expressing human parathormone under the control of a ubiquitous promoter by using a retrovirus vector system.

Transgenic chickens, ubiquitously expressing a human protein, could be a very useful model system for studying the role of human proteins in embryonic development as well as for efficiently producing pharmaceutical drugs as bioreactors. Human parathormone (hPTH) secreted from parathyroid glands plays a significant role in calcium homeostasis and is an important therapeutic agent for the treatment of osteoporosis in humans. Here, by using a robust replication-defective Moloney murine leukemia virus-based retrovirus vector encapsidated with vesicular stomatitis virus G glycoprotein, we generated transgenic chickens expressing hPTH under the control of a ubiquitous Rous sarcoma virus promoter. The recombinant retrovirus was injected into the subgerminal cavity of freshly laid eggs at the blastodermal stage. After 21 d of incubation, 42 chicks hatched from 473 retrovirus-injected eggs. All 42 living chicks were found to express the vector-encoded hPTH gene in diverse organs, as revealed by PCR and reverse transcription-PCR analysis by using primer pairs specific for hPTH. Four days after hatching, 6 chicks died and 14 chicks showed phenotypic deformities. At 18 wk of age, only 3 G(0) chickens survived. They also released the hPTH hormone in their blood and transmitted the hPTH gene to G(1) embryos. However, although the embryos were alive at d 18 of incubation, none hatched. An electrochemiluminescence immunoassay further showed that the hPTH expression level was markedly elevated in mammalian cells infected by the retrovirus vector. Thus, we demonstrated that transgenic chickens, expressing a human protein under the control of a ubiquitous promoter, not only could be an efficient bioreactor for the production of pharmaceutical drugs, but also could be useful for studies on the role of human proteins in embryonic development. To our knowledge, this is the first report on the production of a human protein (hPTH) in transgenic chickens under the control of a ubiquitous promoter by using a replication-defective Moloney murine leukemia virus-based retrovirus vector system.

Molecular characterization of the porcine endogenous retrovirus subclass A and B envelope gene from pigs.

Xenotransplantation of porcine organs has the potential to overcome the current critical shortage of allogenic organs for transplantation in humans. However, the existence of porcine endogenous retroviruses (PERVs) presents a problem for the clinical use of xenografts from pigs. In an attempt to understand the molecular characteristics of PERVs, we cloned the PERV env gene from six pig breeds (ie, Berkshire, Duroc, Landrace, Yorkshire, and two types of miniature pigs) in Korea. A total of 141 env clones were isolated and their sequences were analyzed. Phylogenetic analyses of these genes revealed the presence of PERVs, from both classes A and B, in 54% and 46% of the env clones, respectively. Among these clones, 37 isolates had the correct open reading frame (ORF; 27 clones in subclass A and 10 clones in subclass B), while the others had premature termination. These PERV nucleotide sequences can be used in a database for comparisons of PERV distribution among different pig breeds and for monitoring PERV infection using isolates with functional ORFs. Recombinant envelope of subclass A and B with functional ORF was expressed by vaccinia virus systems. Additionally isolated env clones can be used for various experiments, such as PERV control and infectivity tests, and may enhance the understanding of molecular mechanisms through pseudotyped PERV viruses.

Endogenous and exogenous modulators of potentials evoked by a painful cutaneous laser (LEPs).

Little is known about the specific functions of the human cortical structures receiving nociceptive input, their relationship to various dimensions of pain, and the modulation of these inputs by attention. We now review studies demonstrating the subdural potentials evoked by a cutaneous laser stimulus which produces a pure pain sensation by selective activation of cutaneous nociceptors (LEPs). These LEPs were localized over human anterior and middle cingulate (A & MCC), somatosensory (S1) and parasylvian (PS) cortices. LEP, lesion and imaging data define pain-related elements within each of these structures: insula and parietal operculum within PS, anterior and middle cingulate cortex, and possibly Brodman's areas 3a, 3b and 1 within SI. LEPs recorded over each of these areas is modulated with laser intensity and evoked pain. Attention to the painful laser produces an increase in the amplitude of LEPs over all three cortical areas and emergence of a late positive potential over ACC alone. These studies provide clear evidence of human cortical structures receiving nociceptive input and the modulation of that input by exogenous (e.g. laser intensity) and endogenous factors (e.g. directed attention).

Adenosine receptors and renal ischaemia reperfusion injury.

One of the frequent clinical complications that results in billions of dollars in healthcare costs annually in the United States is acute kidney injury (AKI). Ischaemia reperfusion (IR) injury is a major cause AKI. Unfortunately, no effective treatment or preventive measure for AKI exists. With increased surgical complexity coupled with increasing number of elderly, the incidence of AKI is becoming more frequent. Adenosine is a metabolic breakdown product of adenosine triphosphate (ATP) and contributes to the regulation of multiple physiological events. Extracellular adenosine activates four subtypes of adenosine receptors (AR) including A1 AR, A2 A AR, A2 B AR and A3 AR. In the kidney, adenosine regulates glomerular filtration rate, vascular tone, renin release and is an integrative part of tubular glomerular feedback signal to the afferent arterioles. In addition, each AR subtype powerfully modulates renal IR injury. The A1 AR activation protects against ischaemic insult by reducing apoptosis, necrosis and inflammation. Activation of A2 A AR protects against renal injury by modulating leucocyte-mediated inflammation as well as directly reducing renal tubular inflammation. Activation of A2 B AR acts via direct activation of renal parenchymal as well as renovascular receptors and is important in kidney preconditioning. Finally, activation of A3 AR exacerbates renal damage following renal IR injury while A3 AR antagonism attenuates renal damage following ischaemic insult. Latest body of research suggests that kidney AR modulation may be a promising approach to treat ischaemic AKI. This brief review focuses on the signalling pathways of adenosine in the kidney followed by the role for various AR modulations in protecting against ischaemic AKI.

Inhibition of the activities of P450 cholesterol side-chain cleavage and 3 beta-hydroxysteroid dehydrogenase and the amount of P450 cholesterol side-chain cleavage by testosterone and estradiol-17 beta in hen granulosa cells.

We have found that androgens and estradiol-17 beta (E2) produced by theca cells suppress progesterone (P4) secretion by granulosa cells of the domestic hen in a dose-dependent manner. Furthermore, testosterone (T) and E2 inhibited the conversion of cholesterol to pregnenolone (P5) and of P5 to P4, respectively. The aim of this study was to determine if T and E2 suppress P4 biosynthesis by changing activities of the cytochrome P450 cholesterol side chain cleavage (P450scc) and 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) (Exp I) and the amount of P450scc (Exp II). Granulosa layers of the largest follicle of two to four hens were obtained 22 h before ovulation, pooled, and isolated granulosa cells were prepared. In Exp I, the specific activities of the P450scc and 3 beta-HSD were measured in mitochondrial and microsomal proteins of granulosa cells, respectively, in the presence of T or E2 (0-10 microM). Addition of T to mitochondrial proteins increased the Michaelis-Menten constant (Km) with no change in the maximum velocity (Vmax) of the P450scc, which suggests competitive inhibition (Ki = 30.9 microM), whereas E2 had no effect on Km and Vmax of the P450scc. Likewise, addition of E2 to microsomal proteins increased the Km with no change in the Vmax of the 3 beta-HSD, which suggests competitive inhibition (Ki = 15.1 microM), whereas T had no effect on Km and Vmax of the 3 beta-HSD. In Exp II, granulosa cells (3 x 10(5)/3 ml.tube) were incubated for 0-12 h in triplicate for each combined treatments of 25-OH-cholesterol (8 microM) and cyanoketone (10 microM), T, or E2 (0-10 microM) in the presence or absence of LH (25 ng). Protein content and P5 secretion were measured and the amount of P450scc was determined by Western blot analysis. Incubation of granulosa cells with T decreased the amount of the P450scc in granulosa cells cultured for 12 h and P5 secretion in granulosa cells cultured for 3 h or longer (P less than 0.05), without a change in protein content and cell viability. Our results suggest that P4 production by granulosa cells is suppressed by T and E2 acting as competitive inhibitors of the P450scc and 3 beta-HSD, respectively, and by T decreasing the amount of the P450scc. We conclude that steroidogenesis in the follicle of the chicken is regulated through the interaction of theca and granulosa layers.

Inhibitory sites of androgens and estradiol in progesterone biosynthesis in granulosa cells of the domestic hen.

In a previous in vitro study we found that androgens and estradiol (E2) suppress progesterone (P4) production by the granulosa cells isolated from the largest follicle of the domestic hen in a dose-dependent manner. The presence of an aromatase inhibitor did not block the inhibitory action of androgens. The addition of androgen plus E2 to the granulosa cells had an additive effect on suppressing P4 secretion. The aim of this study was to determine the loci in the steroid biosynthetic pathway where androgens and E2 inhibit P4 production by the granulosa cells. Granulosa layers of the largest follicles removed from two or three hens 22 h before ovulation were pooled. Dispersed granulosa cells were incubated for 3 h in triplicate for each treatment, and pregnenolone (P5) and P4 secretion were measured in medium and cells. Experiments were replicated three or four times. Treatment of granulosa cells with cyanoketone (0-100 microM), an inhibitor of 3 beta-hydroxysteroid dehydrogenase, increased P5 production and decreased P4 production in a dose-dependent manner, with maximal production of P5 and suppression of P4 production at 10 microM cyanoketone. The addition of 25-hydroxycholesterol (25OHCh) or P5 (0-16 microM) caused a dose-related increase in basal and LH-stimulated steroid production. The maximal production of P5 or P4 was found at 8 microM 25OHCh or P5. Also, the effect of LH (0-100 ng) on granulosa cell steroidogenesis was examined with or without 8 microM 25OHCh or P5. The half-maximal and maximal doses for P5 or P4 production were 5 and 25 ng LH, respectively. Next, suppression of P5 production by androstenedione, testosterone, dihydrotestosterone, and E2 (each at 0-10 microM) was tested in the presence of 25OHCh plus cyanoketone with or without LH. We found a dose-dependent suppression of P5 production by androgens (1-10 microM), but not by E2. However, when we added the above steroids to granulosa cells in the presence of P5 with or without LH, only E2 (1 and 10 microM) caused a significant suppression of P4 production. Our results suggest that 1) androgens primarily act at the conversion site of cholesterol to P5 to suppress P4 production; and 2) E2 acts at the conversion site of P5 to P4 to suppress P4 production. We conclude that production of androgens and E2 by thecal cells may regulate P4 biosynthesis by granulosa cells in the domestic hen.

Inhibition of progesterone secretion from granulosa cells by estradiol and androgens in the domestic hen.

We previously reported no difference in progesterone (P4) secretion from the granulosa layer of the largest follicle (F1) of the domestic hen regardless of the maturity of the F1 follicle. However, coincubation of the granulosa and thecal layers resulted in inhibition of P4 secretion from the less mature F1, but not from the more mature F1. The goal of this study was to determine if estradiol (E2) and androgens secreted by the thecal layer suppress P4 production by the granulosa cells. We removed the granulosa layer from less mature F1 follicles and dispersed granulosa cells (1 x 10(5)) were incubated (3 h) in triplicate with one of these treatments: control, E2, testosterone (T), androstenedione (A), and dihydrotestosterone (DHT; at concentrations of 1 x 10(-7), 1 x 10(-6), and 1 x 10(-5) M), LH (100 ng) as well as LH plus E2, T, A, and DHT at the same concentrations. P4 secretion was measured in the medium and cells, and the experiment was replicated seven times. We found a dose-related suppression of basal and LH-stimulated P4 production by all steroids. In a second experiment (n = 3-5), we tested the specificity of the androgens in suppressing P4 production by granulosa cells by using the aromatase inhibitor 7-(4'-amino)phenylthio-4-androstene-3,17-dione. This compound did not reduce the effectiveness of T in suppressing P4 production. Finally in Exp 3 (n = 4-7), E2 and T were tested individually and in combination at concentrations of 1 X 10(-8)-1 X 10(-5) M. We found a possible synergistic effect, in that the combination of E2 plus T suppressed P4 to a greater degree than either steroid alone. Our results indicate that 1) E2 and androgens suppress basal and LH-stimulated P4 production by granulosa cells in a dose-related manner; 2) androgen suppression of P4 production is not mediated by aromatization to estrogen; and 3) the suppressive effects of E2 and androgens may be synergistic. We conclude that E2 and androgens secreted by the thecal layer may regulate P4 production by the granulosa layer.