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How important is the back reaction of electrons via the substrate in dye-sensitized nanocrystalline solar cells?

The role of the conducting glass substrate (fluorine-doped tin oxide, FTO) in the back reaction of electrons with tri-iodide ions in dye-sensitized nanocrystalline solar cells (DSCs) has been investigated using thin-layer electrochemical cells that are analogues of the DSCs. The rate of back reaction is dependent on the type of FTO and the thermal treatment. The results show that this back-reaction route cannot be neglected in DSCs, particularly at lower light intensities, where it is the dominant route for the back transfer of electrons to tri-iodide. This conclusion is confirmed by measurements of the intensity dependence of the photovoltages of DSCs with and without blocking layers. It follows that blocking layers should be used to prevent the back reaction in mechanistic studies in which the light intensity is varied over a wide range. Conclusions based on studies of the intensity dependence of the parameters of DSCs such as photovoltage and electron lifetime in cells without blocking layers, must be critically re-examined.

Journal Article↗

Visible light-induced water oxidation on mesoscopic alpha-Fe2O3 films made by ultrasonic spray pyrolysis.

Alpha-Fe(2)O(3) films having a mesoscopic leaflet type structure were produced for the first time by ultrasonic spray pyrolysis (USP) to explore their potential as oxygen-evolving photoanodes. The target of these studies is to use translucent hematite films deposited on conducting fluorine doped tin oxide (FTO) glass as top electrodes in a tandem cell that accomplishes the cleavage of water into hydrogen and oxygen by sunlight. The properties of layers made by USP were compared to those deposited by conventional spray pyrolysis (SP). Although both types of films show similar XRD and UV-visible and Raman spectra, they differ greatly in their morphology. The mesoscopic alpha-Fe(2)O(3) layers produced by USP consist mainly of 100 nm-sized platelets with a thickness of 5-10 nm. These nanosheets are oriented mainly perpendicularly to the FTO support, their flat surface exposing (001) facets. The mesoscopic leaflet structure has the advantage that it allows for efficient harvesting of visible light, while offering at the same time the very short distance required for the photogenerated holes to reach the electrolyte interface before recombining with conduction band electrons. This allows for water oxidation by the valence band holes even though their diffusion length is only a few nanometers. Distances are longer in the particles produced by SP favoring recombination of photoinduced charge carriers. Open-circuit photovoltage measurements indicate a lower surface state density for the nanoplatelets as compared to the round particles. These factors explain the much higher photoactivity of the USP compared to the SP deposited alpha-Fe(2)O(3) layers. Addition of hydrogen peroxide to the alkaline electrolyte further improves the photocurrent-voltage characteristics of films generated by USP indicating the hole transfer from the valence band of the semiconductor oxide to the adsorbed water to be the rate-limiting kinetic step in the oxygen generation reaction.

Journal Article↗

Experimental evidence of a UV light-induced long-range electric field in nanostructured TiO2 thin films in contact with aqueous electrolytes.

Nanostructured TiO(2) thin-film electrodes of controlled thickness were obtained by immobilization of TiO(2) powder (Degussa P25) on SnO(2):F (FTO)-coated glasses by electrophoresis. The photocurrent-potential characteristics of the electrodes in contact with an indifferent aqueous electrolyte, for both front--and backside UV illumination, show the existence of a macroscopic electric field in the electrode region near the FTO substrate. This electric field, which is only photoinduced in the presence of water (it does not appear in TiO(2) dye-sensitized solar cells under visible illumination), apparently disappears when an efficient hole scavenger, like methanol, is added to the aqueous electrolyte. It is attributed to a nonhomogeneous spatial accumulation of photogenerated holes at surface-bound OH radicals resulting from the photooxidation of chemisorbed water molecules. The influence of film thickness and UV illumination mode (front- and backside) on the photoinduced electric field is analyzed by solving the transport equations for diffusion and drift of electrons.

Journal Article↗

Transgenic crops, biotechnology and ownership rights: what scientists need to know.

Ownership of intellectual and tangible property (IP/TP) rights in agricultural biotechnology (ag-biotech) and transgenic plants has become critically important. For scientists in all institutions, whether industrialized or developing country, public or private sector, an understanding of IP/TP rights is fundamental in both research and development. Transgenic plants and ag-biotech products embody numerous components and processes, each of which may have IP/TP rights attached. To identify these rights, a transgenic plant or ag-biotech product must be dissected into its essential components and processes, with each 'piece' analysed under the IP/TP 'microscope'. This product deconstruction is an integral step in product clearance (PC) analysis leading to freedom to operate (FTO). To facilitate a PC analysis, the following points are important: (1) knowing what one has and where it's from, (2) organizing material transfer agreements and licences, (3) researching scientific and patent databases and relevant literature, (4) instituting a laboratory notebook policy, (5) keeping track of ownership of germplasm and plant genetic resources, and (6) promoting ongoing IP/TP management, awareness and training. However, a FTO opinion does not solve the IP/TP issues of releasing a transgenic plant or ag-biotech product; rather, it is a management tool for assessing the risks of litigation. When transferring transgenic plants or ag-biotech to developing nations, scientists from industrialized countries have the heightened responsibility of verifying that IP/TP issues are fully addressed and documented. Successful technology transfer goes beyond research, development and licensing; it is an holistic package leading to long-term partnerships in international development. Managing IP/TP requires capacity-building in scientists and technology transfer offices, in both industrialized and developing countries.

Biotechnology↗

Liver-specific enhancer of the glucokinase gene.

Glucokinase gene regions that are important for liver specific expression of the enzyme have been functionally identified using transient transfection of rat hepatocytes. Maximal luciferase activity was elicited by a reporter plasmid with 3.4 kilobase pairs of genomic DNA flanking the liver glucokinase promoter. Deletion of a gene fragment between -1000 and -600 with respect to the start of transcription resulted in a 60% decrease in luciferase activity. Further reduction, close to background level, occurred upon deletion of a 90-base pair sequence between -123 and -34. Reporter plasmids with the liver glucokinase promoter and any length of flanking sequence were minimally active in INS-1 insulinoma cells, and conversely reporters with the beta-cell-specific promoter were ineffective in primary hepatocytes. In FTO-2B hepatoma cells, a differentiated line expressing many liver-specific traits but not the endogenous glucokinase gene, the promoter proximal region between -123 and -34 markedly stimulated the expression of transfected plasmids above background. However, addition of the flanking region up to -1000 inhibited luciferase expression. The gene fragment from -1003 to -707 was shown to be a bona fide, hepatocyte-specific enhancer by the following criteria: 1) it stimulated reporter expression by more than 10- and 5-fold when inserted directly upstream of the glucokinase TATA box or complete promoter, respectively, regardless of orientation; 2) it stimulated gene expression from the heterologous SV 40 promoter 4-fold; 3) it was also effective from a downstream position; and 4) in contrast to the enhancer effect in primary hepatocytes, the sequence acted as a silencer in FTO-2B cells and was neutral in INS-1 cells. Both the promoter proximal and the enhancer regions were marked by DNase I hypersensitive sites in the chromatin of primary hepatocytes but not hepatoma or insulinoma cells. Seven footprinted elements termed A through G were mapped in the enhancer by the in vitro DNase I protection assay. Elements A-C may bind liver enriched factors, because they were not protected by spleen nuclear extract. In hepatocyte transfection, the downstream half of the enhancer containing elements A-C was about half as effective as the complete enhancer in stimulating glucokinase promoter activity. Site-directed mutagenesis of element A virtually abrogated the activity of the half-enhancer, whereas mutation of element C had a more moderate effect. The sequence between -732 and -578 upstream of the liver start of transcription in the human glucokinase gene displays 79% sequence identity with the downstream half of the rat enhancer. The human gene fragment ligated to the minimal rat liver glucokinase promoter was shown to work as an enhancer in the hepatocyte transfection system.

Animals↗

Liver glycogen synthase but not the muscle isoform differentiates between glucose 6-phosphate produced by glucokinase or hexokinase.

Using adenovirus-mediated gene transfer into FTO-2B cells, a rat hepatoma cell line, we have overexpressed hexokinase I (HK I), glucokinase (GK), liver glycogen synthase (LGS), muscle glycogen synthase (MGS), and combinations of each of the two glucose-phosphorylating enzymes with each one of the GS isoforms. FTO-2B cells do not synthesize glycogen even when incubated with high doses of glucose. Adenovirus-induced overexpression of HK I and/or LGS, two enzymes endogenously expressed by these cells, did not produce a significant increase in the levels of active GS and the total glycogen content. In contrast, GK overexpression led to the glucose-dependent activation of endogenous or overexpressed LGS and to the accumulation of glycogen. Similarly overexpressed MGS was efficiently activated by the glucose-6-phosphate (Glc-6-P) produced by either endogenous or overexpressed HK I and by overexpressed GK. These results indicate the existence of at least two pools of Glc-6-P in the cell, one of them is accessible to both isoforms of GS and is replenished by the action of GK, whereas LGS is excluded from the cellular compartment where the Glc-6-P produced by HK I is directed. These findings are interpreted in terms of the metabolic role that the two pairs of enzymes, HK I-MGS in the muscle and GK-LGS in the hepatocyte, perform in their respective tissues.

Adenoviridae↗

The role of liver X receptor-alpha in the fatty acid regulation of hepatic gene expression.

Liver X receptors (LXR) alpha and beta play an important role in regulating the expression of genes involved in hepatic bile and fatty acid synthesis, glucose metabolism, as well as sterol efflux. Studies with human embryonic kidney 293 cells indicate that unsaturated fatty acids interfere with oxysterols binding to LXR and antagonize oxysterol-induced LXRalpha activity. In this report, we evaluated the effects of unsaturated fatty acids on LXR-regulated hepatic gene expression. The LXR agonist, T1317, induced mRNAs encoding sterol regulatory element-binding protein 1c (SREBP-1c) and two SREBP-1c-regulated lipogenic genes, e.g. fatty-acid synthase and the S14 protein in primary hepatocytes. Treatment of hepatocytes with eicosapentaenoic acid (20:5n-3) suppressed these mRNAs in the absence and presence of T1317. The cis-regulatory elements targeted by T1317 were not required for fatty-acid suppression of FAS or S14 promoter activity. In contrast to SREBP-1-regulated lipogenic genes, 20:5n-3 had no effect on the T1317 induction of ABCG5 or ABCG8 in the rat hepatoma cell line, FTO-2B. These two genes require LXR but not SREBP-1c for their expression. Feeding rats a diet supplemented with fish oil suppressed hepatic SREBP-1c-regulated genes and induced PPARalpha-regulated genes but had no effect on the LXR-regulated transcripts, CYP7A1, ABCG5, or ABCG8. Transfection studies, using either full-length hLXRalpha or a chimera containing only the LXRalpha ligand binding domain, indicate that a wide array of unsaturated fatty acids had little effect on LXRalpha activity in primary hepatocytes or FTO-2B. These studies suggest that LXRalpha is not a target for unsaturated fatty acid regulation in primary rat hepatocytes or in liver. Thus, oxysterol/LXR-mediated regulation of transcripts involved in bile acid synthesis or sterol efflux appear insensitive to dietary unsaturated fatty acids. The unsaturated fatty acid suppression of SREBP-1 and its targeted lipogenic genes is independent of LXRalpha

Animals↗

Regulation of proline-rich protein and alpha-amylase genes in parotid-hepatoma hybrid cells.

Salivary proline-rich proteins are encoded by tissue-specific multigene families, and are dramatically induced in mice, rats, and hamsters by treatment with the beta agonist isoproterenol. Salivary gland cells, however, are difficult to maintain in a differentiated state in culture and can be induced to synthesize proline-rich protein mRNAs for only a few days. In an attempt to establish a cell line in which it would be possible to regulate proline-rich protein gene transcription, rat parotid gland cells were fused with the rat hepatoma cell line, FTO-2B. Fused cells were obtained that had a frequency of 7.5 x 10(-6), which is about 125-fold greater than the reversion rate of FTO-2B. The hybrid cells exhibited induced proline-rich protein mRNA synthesis when incubated with either dibutyryl cyclic AMP or forskolin. The ability to induce these genes was maintained for at least 20 passages. Most of the fused cell populations also synthesized elevated levels of alpha-amylase mRNA, another tissue-specific gene.

Animals↗

Clinical studies of three oral prodrugs of 5-fluorouracil (capecitabine, UFT, S-1): a review.

Although 5-fluorouracil (5-FU) was first introduced in 1957, it remains an essential part of the treatment of a wide range of solid tumors. 5-FU has antitumor activity against epithelial malignancies arising in the gastrointestinal tract and breast as well as the head and neck, with single-agent response rates of only 10%-30%. Although 5-FU is still the most widely prescribed agent for the treatment of colorectal cancer, less than one-third of patients achieve objective responses. Recent research has focused on the biomodulation of 5-FU to improve the cytotoxicity and therapeutic effectiveness of this drug in the treatment of advanced disease. As all the anticancer agents, 5-FU leads to several toxicities. The toxicity profile of 5-FU is schedule dependent. Myelotoxicity is the major toxic effect in patients receiving bolus doses. Hand-foot syndrome (palmar-plantar erythrodysesthesia), stomatitis, and neuro- and cardiotoxicities are associated with continuous infusions. Other adverse effects associated with both bolus-dose and continuous-infusion regimens include nausea and vomiting, diarrhea, alopecia, and dermatitis. All these reasons explain the need for more effective and less toxic fluoropyrimidines. In the first part of this review, we briefly present the metabolic pathways of 5-FU responsible for the efficacy and toxicity of this drug. This knowledge is also necessary to understand the target(s) of biomodulation. The second part is devoted to a review of the literature on three recent prodrugs of 5-FU, i.e., capecitabine, UFT (ftorafur [FTO] plus uracil), and S-1 (FTO plus 5-chloro-2,4-dihydroxypyridine plus potassium oxonate). The pharmacological principles that have influenced the development of these new drugs and our current knowledge of the clinical pharmacology of these new agents, focusing on antitumor activity and toxicity, are presented. The literature was analyzed until March 2002. This review is intended to be as exhaustive as possible since it was conceived as a work tool for readers wanting to go further.

Administration, Oral↗

Some factors influencing perceived goal distance in time: a preliminary check.

Perceived goal distance in time (PgD) is assumed to be influenced by (a) physical distance in time, (b) the individual's future-time orientation (FTO), (c) perceived intrinsic instrumentality of activity (PiI), and (d) the importance of the goal. The results, based on pupils (159 boys and 151 girls) in Grades 7, 8, and 9, showed that pupils high in future-time orientation (FTO) and perceived intrinsic instrumentality of activity (PiI), perceived any temporal distance (PgD) as shorter than those who were low in these variables. However, the most significant determinant of perceived goal distance in time (PgD), in addition in physical distance in time, was the importance of the future goal; a very important goal being perceived a much closer than an unimportant goal.

Achievement↗

[Determination of the tumor necrosis factor in the peritoneal fluid of gynecologic patients with intraperitoneal infections and endometriosis].

Tumor necrosis factor (TNF-alpha) is a cytokine which can be found in peritoneal fluid (PF) of patients with endometriosis and pelvic inflammatory disease (PID) as a response of inflammatory disorder and infections diseases. The cytotoxic effect of this cytokine could be participating in the pathology of different gynecologic problem and be accountable of the high immunological response and damage on the tubal epithelium. The objective of this study was determinate the presence of TNF-alpha in PF of endometriosis patients, fallopian tube occlusion (FTO) and PID and their correlation with different isolated bacteria. Ten mililiter PF were collected and cultured in antificial medium and Mc Coy culture cells for isolation of acrobic, and anaerobic bacteria and Chlamydia trachomatis from 73 patients by laparoscopy. The TNF-alpha activity was determined by L-929 cells endometriosis, 30 PID and 4 had miomas and adherences. The 50.7% of patients were cultive positive, fom these, 31.5% were PID. Chlamydia trachomatis (16%) was the most frecuenty isolated bacteria in these patients. 59.4% of FTO patients displayed TNF-alpha activity. However, only 4% showed positive isolation, in conclusion the detection of TNF-alpha could be useful in active infectious and inflammatory diseases in patients which not present simptomatologic characteristic of these illnesses and plus being attended at for sterility clinical as a result of their incapacity to get pregnant.

Ascitic Fluid↗

Lithium inhibits hepatic gluconeogenesis and phosphoenolpyruvate carboxykinase gene expression.

Incubation of isolated hepatocytes from fasted rats with 20 mM LiCl for 1 h decreased glucose production from lactate, pyruvate, and alanine. In addition, phosphoenolpyruvate carboxykinase (PEPCK) gene expression in FTO-2B rat hepatoma cells was inhibited by treatment with LiCl. Lithium was also able to counteract the increased PEPCK mRNA levels caused by both Bt2cAMP and dexamethasone, in a concentration-dependent manner. A chimeric gene containing the PEPCK promoter (-550 to +73) linked to the amino-3-glycosyl phosphotransferase (neo) structural gene was transduced into FTO-2B cells using a Moloney murine leukemia virus-based retrovirus. In these infected cells, 20 mM LiCl decreased both the concentration of neo mRNA transcribed from the PEPCK-neo chimeric gene and mRNA from the endogenous PEPCK gene. Lithium also inhibited the stimulatory effect of Bt2cAMP and dexamethasone on both genes. The stability of neo mRNA was not altered by lithium, since in cells infected with retrovirus containing only the neo gene transcribed via the retroviral 5'-LTR and treated with 20 mM LiCl, no change in neo mRNA levels was observed. The intraperitoneal administration of LiCl to rats caused a decrease in hepatic PEPCK mRNA, indicating that lithium could also modify gene expression in vivo. The effects of lithium were not due to an increase in the concentration of insulin in the blood but were correlated with an increase in hepatic glycogen and fructose 2,6-bisphosphate levels. These results indicate that lithium ions, at concentrations normally used therapeutically for depression in humans, can inhibit glucose synthesis in the liver by a mechanism which can selectively modify the expression of hepatic phosphoenolpyruvate carboxykinase.

Animals↗

Characterization of the phosphoenolpyruvate carboxykinase (GTP) promoter-regulatory region. I. Multiple hormone regulatory elements and the effects of enhancers.

Transcription of the gene for cytosolic Phosphoenolpyruvate carboxykinase (GTP) (EC 4.1.1.32) (PEPCK) from rat liver is increased by cAMP and glucocorticoids and decreased by insulin. A PEPCK-thymidine kinase (TK) chimeric gene was transfected into FTO-2B rat hepatoma cells, which were TK-deficient. Previous studies showed that a cAMP regulatory element is located at the 5' end of the PEPCK gene. In this report, we demonstrate that the 5' end of the gene also contains a glucocorticoid regulatory element, but not one for insulin. Regions of the PEPCK gene that contain these regulatory elements were attached to the Herpes simplex virus TK structural gene containing its own promoter. The hormone regulatory elements within the 5' flanking region of the PEPCK gene conferred cAMP and glucocorticoid responsiveness on the TK gene after transfection into FTO-2B cells. Like viral enhancer elements, these regulatory elements functioned properly when placed in either orientation at various positions 5' or 3' to TK. The presence of the SV40 enhancer element upstream from the PEPCK-TK gene had little effect on the basal level of expression or hormonal regulation of the chimeric gene.

Animals↗

Identification of a cAMP regulatory region in the gene for rat cytosolic phosphoenolpyruvate carboxykinase (GTP). Use of chimeric genes transfected into hepatoma cells.

cAMP stimulates the transcription of the gene for the cytosolic form of phosphoenolpyruvate carboxykinase (GTP) (EC 4.1.1.32) (PEPCK) in rat liver. We have investigated the nucleotide sequences required for regulation of PEPCK gene expression by cAMP. A chimeric gene was constructed in which a 620-base pair fragment of the 5'-end of the PEPCK gene (including 547 base pairs of 5'-flanking sequence) was ligated to the herpes simplex virus thymidine kinase (TK) structural gene. The PEPCK promoter fragment was introduced either in the proper orientation for transcription of the TK gene or in the opposite orientation. These fusion genes and the parent vector, pOPF, which contains the intact TK gene, were transfected individually into TK-deficient FTO-2B rat hepatoma cells. FTO-2B cells contain an active endogenous PEPCK gene which is stimulated by cAMP. Cells were selected in HAT medium and grown either as mass cell cultures or as individual clones. Dibutyryl cyclic AMP (Bt2cAMP) plus theophylline (16 h) stimulated TK activity 1.6-6.1-fold in cell lines transfected with the PEPCK-TK fusion gene containing the PEPCK promoter fragment in the correct orientation. However, the intact TK gene was not induced by Bt2cAMP after transfection, nor was there any expression of the PEPCK-TK fusion gene in cells which contained the PEPCK promoter fragment in the wrong transcriptional orientation. Bt2cAMP also increased the levels of TK mRNA in cells transfected with the PEPCK-TK fusion gene, but not in cells transfected with the intact TK gene. The chimeric PEPCK-TK mRNA initiated at the PEPCK start site, as determined by S1 nuclease mapping. There was no relationship between the number of copies of the PEPCK-TK gene integrated in the various cell lines and either the basal level of TK activity or its inducibility of Bt2cAMP.

Animals↗

Chronic nitric oxide mediates dual-layer gene regulation through mRNA m6A positional remodeling and parallel transcriptional reprogramming.

Nitric oxide (NO) is a pleiotropic free radical that functions as a master regulator of gene expression, and its sustained production within the tumor microenvironment reshapes the epitranscriptomic state of cancer cells. We previously demonstrated that NO inhibits the m6A mRNA demethylases FTO and ALKBH5 through dinitrosyliron complex formation while leaving the methyltransferase METTL3 intact, a demethylase-specific perturbation that increases global m6A on mRNA. Here, integrating m6A-RIP-seq and RNA-seq from triple-negative breast cancer cells, we show that chronic NO does not produce the uniform hypermethylation anticipated from demethylase inhibition. Instead, it redistributes m6A on mRNA, enriching the 5'UTR and coding sequence while depleting the 3'UTR and departing from the canonical stop-codon and 3'UTR topology. We found that the position of m6A, rather than its intensity or mere presence, shapes the outcome, in part by determining which reader protein is predicted to recognize it. In parallel, NO drives a canonical NF-κB and inflammatory transcriptional program. The transcriptional program is independent of the m6A methylome in both which genes respond and how strongly they respond, ruling out a linear methylome-to-transcriptome cascade; even so, m6A position remains associated with the direction of change among responding transcripts. The 3'UTR is the primary site of m6A loss and shows a suggestive computational link to miRNA-mediated regulation. Sense-antisense coordination reinforces the transcriptional response without bridging the two programs. These findings demonstrate that NO not only increases m6A abundance, but it also rewrites the m6A positional code, establishing spatial reprogramming of the epitranscriptome as a previously unrecognized mode of gene regulation.

RNA Methylation↗

m6A regulator-based molecular classification and hub genes associated with immune infiltration characteristics and clinical outcomes in diffuse gliomas.

BACKGROUND: m6A methylation modification is a new regulatory mechanism involved in tumorigenesis and tumor-immunity interaction. However, its impact on glioma immune microenvironment and clinical outcomes remains unclear. METHODS: Comprehensive expression profiles of 18 m6A regulators were used to identify molecular subtypes exhibiting distinct m6A modification patterns in 1673 glioma samples sourced from public datasets. A multi-genes signature was constructed for predicting clinical outcomes and response to immunotherapy in glioma patients. Immunohistochemistry and cellular experiments were performed for validation. RESULTS: Two m6A subtypes of gliomas were identified. The m6A-low-risk subtype was characterized by paucity of immune infiltrates; While the m6A-high-risk subtype had higher abundances of multiple immune cells including lymphocyte and macrophage as well as increased expression of PD-L1, corresponding to an immunosuppressive phenotype. The m6A-high-risk subtype had poorer survival than the m6A-low-risk subtype in both the glioblastoma and lower grade gliomas cohorts. Eight m6A-related hub genes of high prognostic significances were identified and selected for developing a scoring signature termed as m6Ascore. Elevated m6Ascore indicated worse survival for glioma patients under standard care, but showed enhanced response to immunotherapy. Moreover, we demonstrated that overexpression of FTO, a m6A demethylase, inhibited the expressions of m6A-related hub genes (PTX3, SPAG4), impaired glioma cell viability and reduced macrophage chemotaxis. CONCLUSION: This work develops an immune- and clinical-relevant m6A subtyping and a scoring model, which enhances our understanding of the role of m6A modification in regulating immune infiltration microenvironment in gliomas and helps to identify patients who are more likely to benefit from immunotherapy.

Humans↗

Polycystic Ovary Syndrome Physiologic Pathways Implicated Through Clustering of Genetic Loci.

CONTEXT: Polycystic ovary syndrome (PCOS) is a heterogeneous disorder, with disease loci identified from genome-wide association studies (GWAS) having largely unknown relationships to disease pathogenesis. OBJECTIVE: This work aimed to group PCOS GWAS loci into genetic clusters associated with disease pathophysiology. METHODS: Cluster analysis was performed for 60 PCOS-associated genetic variants and 49 traits using GWAS summary statistics. Cluster-specific PCOS partitioned polygenic scores (pPS) were generated and tested for association with clinical phenotypes in the Mass General Brigham Biobank (MGBB, N = 62 252). Associations with clinical outcomes (type 2 diabetes [T2D], coronary artery disease [CAD], and female reproductive traits) were assessed using both GWAS-based pPS (DIAMANTE, N = 898,130, CARDIOGRAM/UKBB, N = 547 261) and individual-level pPS in MGBB. RESULTS: Four PCOS genetic clusters were identified with top loci indicated as following: (i) cluster 1/obesity/insulin resistance (FTO); (ii) cluster 2/hormonal/menstrual cycle changes (FSHB); (iii) cluster 3/blood markers/inflammation (ATXN2/SH2B3); (iv) cluster 4/metabolic changes (MAF, SLC38A11). Cluster pPS were associated with distinct clinical traits: Cluster 1 with increased body mass index (P = 6.6 × 10-29); cluster 2 with increased age of menarche (P = 1.5 × 10-4); cluster 3 with multiple decreased blood markers, including mean platelet volume (P = 3.1 ×10-5); and cluster 4 with increased alkaline phosphatase (P = .007). PCOS genetic clusters GWAS-pPSs were also associated with disease outcomes: cluster 1 pPS with increased T2D (odds ratio [OR] 1.07; P = 7.3 × 10-50), with replication in MGBB all participants (OR 1.09, P = 2.7 × 10-7) and females only (OR 1.11, 4.8 × 10-5). CONCLUSION: Distinct genetic backgrounds in individuals with PCOS may underlie clinical heterogeneity and disease outcomes.

Humans↗

Homozygous Ft embryos are affected in floor plate maintenance and ventral neural tube patterning.

Sonic hedgehog (Shh), produced by the notochord and floor plate cells of the neural tube, plays a critical role in organizing dorsal-ventral patterning in the developing neural tube. We have investigated neural tube development in mouse embryos homozygous for the Fused toes (Ft) mutation, a deletion composed of genes of the Iroquois B (IrxB) cluster and of Fts, Ftm, and Fto. In Ft mutants starting from embryonic day 10.5, the floor plate appeared to degenerate and the notochord failed to undergo ventral displacement from the spinal cord. Consistent with the loss of Shh signalling from the floor plate, V3 neuron generation was reduced in Ft/Ft embryos and the domain of motor neuron generation expanded ventrally at the expense of V2 neurons. These data support the idea that Ft genes play an important role in dorsal-ventral patterning of the neural tube acting to define the extent of motor neuron generation; moreover, the data reveal a previously unanticipated function for Ft genes in the maintenance of the floor plate.

Animals↗