15 results on '"Robertson CC"'
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2. Human vascularized macrophage-islet organoids to model immune-mediated pancreatic β cell pyroptosis upon viral infection.
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Yang L, Han Y, Zhang T, Dong X, Ge J, Roy A, Zhu J, Lu T, Jeya Vandana J, de Silva N, Robertson CC, Xiang JZ, Pan C, Sun Y, Que J, Evans T, Liu C, Wang W, Naji A, Parker SCJ, Schwartz RE, and Chen S
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- Humans, COVID-19 immunology, COVID-19 pathology, COVID-19 virology, SARS-CoV-2 immunology, Pluripotent Stem Cells metabolism, Pyroptosis, Organoids virology, Organoids immunology, Organoids pathology, Macrophages immunology, Macrophages virology, Macrophages metabolism, Insulin-Secreting Cells virology, Insulin-Secreting Cells pathology, Insulin-Secreting Cells immunology
- Abstract
There is a paucity of human models to study immune-mediated host damage. Here, we utilized the GeoMx spatial multi-omics platform to analyze immune cell changes in COVID-19 pancreatic autopsy samples, revealing an accumulation of proinflammatory macrophages. Single-cell RNA sequencing (scRNA-seq) analysis of human islets exposed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or coxsackievirus B4 (CVB4) viruses identified activation of proinflammatory macrophages and β cell pyroptosis. To distinguish viral versus proinflammatory-macrophage-mediated β cell pyroptosis, we developed human pluripotent stem cell (hPSC)-derived vascularized macrophage-islet (VMI) organoids. VMI organoids exhibited enhanced marker expression and function in both β cells and endothelial cells compared with separately cultured cells. Notably, proinflammatory macrophages within VMI organoids induced β cell pyroptosis. Mechanistic investigations highlighted TNFSF12-TNFRSF12A involvement in proinflammatory-macrophage-mediated β cell pyroptosis. This study established hPSC-derived VMI organoids as a valuable tool for studying immune-cell-mediated host damage and uncovered the mechanism of β cell damage during viral exposure., Competing Interests: Declaration of interests R.E.S. is on the scientific advisory board of Miromatrix Inc. and Lime Therapeutics and is a consultant and speaker for Alnylam Inc. S.C. and T.E are the co-founders of OncoBeat, LLC. S.C. is a consultant of Vesalius Therapeutics and co-founder of iOrganBio., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)
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- 2024
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3. A comprehensive summary of eponymous awards and scholarships in sexual medicine.
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Alvermann TA, Robertson CC, Jones JM 3rd, and Gross MS
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Introduction: Numerous eponymous awards and scholarships exist within sexual medicine. This comprehensive review is intended to summarize these awards and highlight the esteemed sexual medicine experts for whom these awards are named., Objectives: To provide historical background and context for the various eponymous awards in sexual medicine., Methods: The websites of the International Society for Sexual Medicine (ISSM) and the regional affiliate societies, including the Sexual Medicine Society of North America (SMSNA), International Society for the Study of Women's Sexual Health (ISSWSH), and various regional societies were identified, and all awards associated with a member of note were documented. In cases where no awards were identified within a regional society and a contact person was available, inquiries were made regarding the existence of awards. Several documents on the history of the ISSM were utilized for background on awards., Results: A comprehensive list of current awards and their history was compiled., Conclusion: This is the first comprehensive history of eponymous awards and scholarships available in sexual medicine., (© The Author(s) 2024. Published by Oxford University Press on behalf of The International Society for Sexual Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2024
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4. Single-cell transcriptomic profiling of human pancreatic islets reveals genes responsive to glucose exposure over 24 h.
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Grenko CM, Taylor HJ, Bonnycastle LL, Xue D, Lee BN, Weiss Z, Yan T, Swift AJ, Mansell EC, Lee A, Robertson CC, Narisu N, Erdos MR, Chen S, Collins FS, and Taylor DL
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- Humans, Transcriptome, Diabetes Mellitus, Type 2 genetics, Diabetes Mellitus, Type 2 metabolism, Insulin metabolism, Insulin-Secreting Cells metabolism, Insulin-Secreting Cells drug effects, Hyperglycemia genetics, Hyperglycemia metabolism, Islets of Langerhans metabolism, Islets of Langerhans drug effects, Glucose pharmacology, Glucose metabolism, Single-Cell Analysis, Gene Expression Profiling
- Abstract
Aims/hypothesis: Disruption of pancreatic islet function and glucose homeostasis can lead to the development of sustained hyperglycaemia, beta cell glucotoxicity and subsequently type 2 diabetes. In this study, we explored the effects of in vitro hyperglycaemic conditions on human pancreatic islet gene expression across 24 h in six pancreatic cell types: alpha; beta; gamma; delta; ductal; and acinar. We hypothesised that genes associated with hyperglycaemic conditions may be relevant to the onset and progression of diabetes., Methods: We exposed human pancreatic islets from two donors to low (2.8 mmol/l) and high (15.0 mmol/l) glucose concentrations over 24 h in vitro. To assess the transcriptome, we performed single-cell RNA-seq (scRNA-seq) at seven time points. We modelled time as both a discrete and continuous variable to determine momentary and longitudinal changes in transcription associated with islet time in culture or glucose exposure. Additionally, we integrated genomic features and genetic summary statistics to nominate candidate effector genes. For three of these genes, we functionally characterised the effect on insulin production and secretion using CRISPR interference to knock down gene expression in EndoC-βH1 cells, followed by a glucose-stimulated insulin secretion assay., Results: In the discrete time models, we identified 1344 genes associated with time and 668 genes associated with glucose exposure across all cell types and time points. In the continuous time models, we identified 1311 genes associated with time, 345 genes associated with glucose exposure and 418 genes associated with interaction effects between time and glucose across all cell types. By integrating these expression profiles with summary statistics from genetic association studies, we identified 2449 candidate effector genes for type 2 diabetes, HbA
1c , random blood glucose and fasting blood glucose. Of these candidate effector genes, we showed that three (ERO1B, HNRNPA2B1 and RHOBTB3) exhibited an effect on glucose-stimulated insulin production and secretion in EndoC-βH1 cells., Conclusions/interpretation: The findings of our study provide an in-depth characterisation of the 24 h transcriptomic response of human pancreatic islets to glucose exposure at a single-cell resolution. By integrating differentially expressed genes with genetic signals for type 2 diabetes and glucose-related traits, we provide insights into the molecular mechanisms underlying glucose homeostasis. Finally, we provide functional evidence to support the role of three candidate effector genes in insulin secretion and production., Data Availability: The scRNA-seq data from the 24 h glucose exposure experiment performed in this study are available in the database of Genotypes and Phenotypes (dbGap; https://www.ncbi.nlm.nih.gov/gap/ ) with accession no. phs001188.v3.p1. Study metadata and summary statistics for the differential expression, gene set enrichment and candidate effector gene prediction analyses are available in the Zenodo data repository ( https://zenodo.org/ ) under accession number 11123248. The code used in this study is publicly available at https://github.com/CollinsLabBioComp/publication-islet_glucose_timecourse ., (© 2024. The Author(s).)- Published
- 2024
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5. In Vitro and In Vivo Studies on a Mononuclear Ruthenium Complex Reveals It is a Highly Effective, Fast-Acting, Broad-Spectrum Antimicrobial in Physiologically Relevant Conditions.
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Varney AM, Smitten KL, Southam HM, Fairbanks SD, Robertson CC, Thomas JA, and McLean S
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- Animals, Moths drug effects, Moths microbiology, Staphylococcus aureus drug effects, Humans, Urinary Tract Infections microbiology, Urinary Tract Infections drug therapy, Coordination Complexes pharmacology, Coordination Complexes chemistry, Staphylococcal Infections drug therapy, Staphylococcal Infections microbiology, Anti-Bacterial Agents pharmacology, Anti-Bacterial Agents chemistry, Microbial Sensitivity Tests, Ruthenium chemistry, Ruthenium pharmacology
- Abstract
The crystal structure of a previously reported antimicrobial Ru
II complex that targets bacterial DNA is presented. Studies utilizing clinical isolates of Gram-negative bacteria that cause catheter-associated urinary tract infection, (CA)UTI, in media that model urine and plasma reveal that good antimicrobial activity is maintained in all conditions tested. Experiments with a series of Staphylococcus aureus clinical isolates show that, unlike the majority of previously reported RuII -based antimicrobial leads, the compound retains its potent activity even in MRSA strains. Furthermore, experiments using bacteria in early exponential growth and at different pHs reveal that the compound also retains its activity across a range of conditions that are relevant to those encountered in clinical settings. Combinatorial studies involving cotreatment with conventional antibiotics or a previously reported analogous dinuclear RuII complex showed no antagonistic effects. In fact, although all combinations show distinct additive antibacterial activity, in one case, this effect approaches synergy. It was found that the Galleria Mellonella model organism infected with a multidrug resistant strain of the ESKAPE pathogen Acinetobacter baumannii could be successfully treated and totally cleared within 48 h after a single dose of the lead complex with no detectable deleterious effect to the host.- Published
- 2024
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6. Untangling the genetics of beta cell dysfunction and death in type 1 diabetes.
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Robertson CC, Elgamal RM, Henry-Kanarek BA, Arvan P, Chen S, Dhawan S, Eizirik DL, Kaddis JS, Vahedi G, Parker SCJ, Gaulton KJ, and Soleimanpour SA
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- Humans, Genetic Predisposition to Disease, Animals, Cell Death genetics, Genome-Wide Association Study, Diabetes Mellitus, Type 1 genetics, Diabetes Mellitus, Type 1 metabolism, Insulin-Secreting Cells metabolism
- Abstract
Background: Type 1 diabetes (T1D) is a complex multi-system disease which arises from both environmental and genetic factors, resulting in the destruction of insulin-producing pancreatic beta cells. Over the past two decades, human genetic studies have provided new insight into the etiology of T1D, including an appreciation for the role of beta cells in their own demise., Scope of Review: Here, we outline models supported by human genetic data for the role of beta cell dysfunction and death in T1D. We highlight the importance of strong evidence linking T1D genetic associations to bona fide candidate genes for mechanistic and therapeutic consideration. To guide rigorous interpretation of genetic associations, we describe molecular profiling approaches, genomic resources, and disease models that may be used to construct variant-to-gene links and to investigate candidate genes and their role in T1D., Major Conclusions: We profile advances in understanding the genetic causes of beta cell dysfunction and death at individual T1D risk loci. We discuss how genetic risk prediction models can be used to address disease heterogeneity. Further, we present areas where investment will be critical for the future use of genetics to address open questions in the development of new treatment and prevention strategies for T1D., Competing Interests: Declaration of competing interest KJG has done consulting for Genentech, received honoraria from Pfizer, and holds stock in Neurocrine biosciences. S.C. is the co-founders of OncoBeat, LLC. S.A.S has received grant funding from Ono Pharmaceutical Co., Ltd. and is a consultant for Novo Nordisk. DLE is a member of the Scientific Advisory Board of InSphero AG., (Copyright © 2024 The Authors. Published by Elsevier GmbH.. All rights reserved.)
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- 2024
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7. Stereoselective Asymmetric Syntheses of Molecules with a 4,5-Dihydro-1 H -[1,2,4]-Triazoline Core Possessing an Acetylated Carbohydrate Appendage: Crystal Structure, Spectroscopy, and Pharmacology.
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Al Maqbali AS, Al Rasbi NK, Zoghaib WM, Sivakumar N, Robertson CC, Shongwe MS, Grzegorzek N, and Abdel-Jalil RJ
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- Humans, Crystallography, X-Ray, Cell Line, Tumor, Antineoplastic Agents pharmacology, Antineoplastic Agents chemistry, Antineoplastic Agents chemical synthesis, Carbohydrates chemistry, Molecular Structure, Stereoisomerism, Acetylation, Structure-Activity Relationship, Magnetic Resonance Spectroscopy, Triazoles chemistry, Triazoles pharmacology, Triazoles chemical synthesis
- Abstract
A new series of chiral 4,5-dihydro-1 H -[1,2,4]-triazoline molecules, featuring a β-ᴅ-glucopyranoside appendage, were synthesized via a 1,3-dipolar cycloaddition reaction between various hydrazonyl chlorides and carbohydrate Schiff bases. The isolated enantiopure triazolines ( 8a - j ) were identified through high-resolution mass spectrometry (HRMS) and vibrational spectroscopy. Subsequently, their solution structures were elucidated through NMR spectroscopic techniques. Single-crystal X-ray analysis of derivative 8b provided definitive evidence for the 3-D structure of this compound and revealed important intermolecular forces in the crystal lattice. Moreover, it confirmed the ( S )-configuration at the newly generated stereo-center. Selected target compounds were investigated for anti-tumor activity in 60 cancer cell lines, with derivative 8c showing the highest potency, particularly against leukemia. Additionally, substituent-dependent anti-fungal and anti-bacterial behavior was observed.
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- 2024
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8. A multi-ancestry genome-wide association study in type 1 diabetes.
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Michalek DA, Tern C, Zhou W, Robertson CC, Farber E, Campolieto P, Chen WM, Onengut-Gumuscu S, and Rich SS
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- Humans, Male, Female, White People genetics, Age of Onset, Alleles, HLA-DQ alpha-Chains genetics, Black People genetics, Child, Hispanic or Latino genetics, HLA Antigens genetics, Adolescent, Diabetes Mellitus, Type 1 genetics, Genome-Wide Association Study, Polymorphism, Single Nucleotide, Genetic Predisposition to Disease
- Abstract
Type 1 diabetes (T1D) is an autoimmune disease caused by destruction of the pancreatic β-cells. Genome-wide association (GWAS) and fine mapping studies have been conducted mainly in European ancestry (EUR) populations. We performed a multi-ancestry GWAS to identify SNPs and HLA alleles associated with T1D risk and age at onset. EUR families (N = 3223), and unrelated individuals of African (AFR, N = 891) and admixed (Hispanic/Latino) ancestry (AMR, N = 308) were genotyped using the Illumina HumanCoreExome BeadArray, with imputation to the TOPMed reference panel. The Multi-Ethnic HLA reference panel was utilized to impute HLA alleles and amino acid residues. Logistic mixed models (T1D risk) and frailty models (age at onset) were used for analysis. In GWAS meta-analysis, seven loci were associated with T1D risk at genome-wide significance: PTPN22, HLA-DQA1, IL2RA, RNLS, INS, IKZF4-RPS26-ERBB3, and SH2B3, with four associated with T1D age at onset (PTPN22, HLA-DQB1, INS, and ERBB3). AFR and AMR meta-analysis revealed NRP1 as associated with T1D risk and age at onset, although NRP1 variants were not associated in EUR ancestry. In contrast, the PTPN22 variant was significantly associated with risk only in EUR ancestry. HLA alleles and haplotypes most significantly associated with T1D risk in AFR and AMR ancestry differed from that seen in EUR ancestry; in addition, the HLA-DRB1*08:02-DQA1*04:01-DQB1*04:02 haplotype was 'protective' in AMR while HLA-DRB1*08:01-DQA1*04:01-DQB1*04:02 haplotype was 'risk' in EUR ancestry, differing only at HLA-DRB1*08. These results suggest that much larger sample sizes in non-EUR populations are required to capture novel loci associated with T1D risk., (© The Author(s) 2024. Published by Oxford University Press.)
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- 2024
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9. Phenazine Cations as Anticancer Theranostics † .
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Noakes FF, Smitten KL, Maple LEC, Bernardino de la Serna J, Robertson CC, Pritchard D, Fairbanks SD, Weinstein JA, Smythe CGW, and Thomas JA
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- Humans, Lysosomes metabolism, Lysosomes drug effects, HEK293 Cells, Apoptosis drug effects, Drug Screening Assays, Antitumor, Cell Line, Tumor, Animals, Theranostic Nanomedicine, Molecular Structure, Antineoplastic Agents pharmacology, Antineoplastic Agents chemistry, Antineoplastic Agents chemical synthesis, Cations chemistry, Cations pharmacology, Phenazines chemistry, Phenazines pharmacology
- Abstract
The biological properties of two water-soluble organic cations based on polypyridyl structures commonly used as ligands for photoactive transition metal complexes designed to interact with biomolecules are investigated. A cytotoxicity screen employing a small panel of cell lines reveals that both cations show cytotoxicity toward cancer cells but show reduced cytotoxicity to noncancerous HEK293 cells with the more extended system being notably more active. Although it is not a singlet oxygen sensitizer, the more active cation also displayed enhanced potency on irradiation with visible light, making it active at nanomolar concentrations. Using the intrinsic luminescence of the cations, their cellular uptake was investigated in more detail, revealing that the active compound is more readily internalized than its less lipophilic analogue. Colocalization studies with established cell probes reveal that the active cation predominantly localizes within lysosomes and that irradiation leads to the disruption of mitochondrial structure and function. Stimulated emission depletion (STED) nanoscopy and transmission electron microscopy (TEM) imaging reveal that treatment results in distinct lysosomal swelling and extensive cellular vacuolization. Further imaging-based studies confirm that treatment with the active cation induces lysosomal membrane permeabilization, which triggers lysosome-dependent cell-death due to both necrosis and caspase-dependent apoptosis. A preliminary toxicity screen in the Galleria melonella animal model was carried out on both cations and revealed no detectable toxicity up to concentrations of 80 mg/kg. Taken together, these studies indicate that this class of synthetically easy-to-access photoactive compounds offers potential as novel therapeutic leads.
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- 2024
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10. Generation of Human Isogenic Induced Pluripotent Stem Cell Lines with CRISPR Prime Editing.
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Bonnycastle LL, Swift AJ, Mansell EC, Lee A, Winnicki E, Li ES, Robertson CC, Parsons VA, Huynh T, Krilow C, Mohlke KL, Erdos MR, Narisu N, and Collins FS
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- Humans, Clustered Regularly Interspaced Short Palindromic Repeats genetics, CRISPR-Cas Systems genetics, Gene Editing, RNA, Guide, CRISPR-Cas Systems, Diabetes Mellitus, Type 2, Induced Pluripotent Stem Cells
- Abstract
We developed an efficient CRISPR prime editing protocol and generated isogenic-induced pluripotent stem cell (iPSC) lines carrying heterozygous or homozygous alleles for putatively causal single nucleotide variants at six type 2 diabetes loci ( ABCC8 , MTNR1B , TCF7L2 , HNF4A , CAMK1D , and GCK ). Our two-step sequence-based approach to first identify transfected cell pools with the highest fraction of edited cells significantly reduced the downstream efforts to isolate single clones of edited cells. We found that prime editing can make targeted genetic changes in iPSC and optimization of system components and guide RNA designs that were critical to achieve acceptable efficiency. Systems utilizing PEmax, epegRNA modifications, and MLH1dn provided significant benefit, producing editing efficiencies of 36-73%. Editing success and pegRNA design optimization required for each variant differed depending on the sequence at the target site. With attention to design, prime editing is a promising approach to generate isogenic iPSC lines, enabling the study of specific genetic changes in a common genetic background.
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- 2024
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11. Ultrafast electronic, infrared, and X-ray absorption spectroscopy study of Cu(I) phosphine diimine complexes.
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Appleby MV, Cowin RA, Ivalo II, Peralta-Arriaga SL, Robertson CC, Bartlett S, Fitzpatrick A, Dent A, Karras G, Diaz-Moreno S, Chekulaev D, and Weinstein JA
- Abstract
The study aims to understand the role of the transient bonding in the interplay between the structural and electronic changes in heteroleptic Cu(I) diimine diphosphine complexes. This is an emerging class of photosensitisers which absorb in the red region of the spectrum, whilst retaining a sufficiently long excited state lifetime. Here, the dynamics of these complexes are explored by transient absorption (TA) and time-resolved infrared (TRIR) spectroscopy, which reveal ultrafast intersystem crossing and structural distortion occurring. Two potential mechanisms affecting excited state decay in these complexes involve a transient formation of a solvent adduct, made possible by the opening up of the Cu coordination centre in the excited state due to structural distortion, and by a transient coordination of the O-atom of the phosphine ligand to the copper center. X-ray absorption studies of the ground electronic state have been conducted as a prerequisite for the upcoming X-ray spectroscopy studies which will directly determine structural dynamics. The potential for these complexes to be used in bimolecular applications is confirmed by a significant yield of singlet oxygen production.
- Published
- 2023
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12. Single-cell transcriptomic profiling of human pancreatic islets reveals genes responsive to glucose exposure over 24 hours.
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Grenko CM, Bonnycastle LL, Taylor HJ, Yan T, Swift AJ, Robertson CC, Narisu N, Erdos MR, Collins FS, and Taylor DL
- Abstract
Disruption of pancreatic islet function and glucose homeostasis can lead to the development of sustained hyperglycemia, beta cell glucotoxicity, and ultimately type 2 diabetes (T2D). In this study, we sought to explore the effects of hyperglycemia on human pancreatic islet (HPI) gene expression by exposing HPIs from two donors to low (2.8mM) and high (15.0mM) glucose concentrations over 24 hours, assaying the transcriptome at seven time points using single-cell RNA sequencing (scRNA-seq). We modeled time as both a discrete and continuous variable to determine momentary and longitudinal changes in transcription associated with islet time in culture or glucose exposure. Across all cell types, we identified 1,528 genes associated with time, 1,185 genes associated with glucose exposure, and 845 genes associated with interaction effects between time and glucose. We clustered differentially expressed genes across cell types and found 347 modules of genes with similar expression patterns across time and glucose conditions, including two beta cell modules enriched in genes associated with T2D. Finally, by integrating genomic features from this study and genetic summary statistics for T2D and related traits, we nominate 363 candidate effector genes that may underlie genetic associations for T2D and related traits.
- Published
- 2023
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13. 2,2':4,4'':4',4'''-Quaterpyridine: synthesis, crystal-structure description, and Hirshfeld surface analysis.
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Aderinto SO, Thomas JA, and Robertson CC
- Abstract
The title compound, 2,2':4,4'':4',4'''-quaterpyridine (Qtpy), C
20 H14 N4 , crystallizes in the triclinic P space group and has half of the mol-ecule in the asymmetric unit, corresponding to 4,4'-bi-pyridine (4,4'-bpy) that serves as the building block for the mol-ecule. C4,4'-bpy -N-C4,4'-bpy and/or N-C4,4'-bpy -C4,4'-bpy bond-angle parameters show that the 4,4'-bpy ligands are highly rigid, displaying values lower than the linear bond angle of 180°. In the crystal, the 4,4'-bpy units are seen to be facing each other in relatively close proximity. The most important inter-actions on the Hirshfeld Surface of the compound are C-H⋯N/H⋯N-C inter-actions (constituting 10.6% and 7.6% of the total surface)., (© Aderinto et al. 2023.)- Published
- 2023
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14. Photocatalytic Reduction of CO 2 to CO in Aqueous Solution under Red-Light Irradiation by a Zn-Porphyrin-Sensitized Mn(I) Catalyst.
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Shipp J, Parker S, Spall S, Peralta-Arriaga SL, Robertson CC, Chekulaev D, Portius P, Turega S, Buckley A, Rothman R, and Weinstein JA
- Abstract
This work demonstrates photocatalytic CO
2 reduction by a noble-metal-free photosensitizer-catalyst system in aqueous solution under red-light irradiation. A water-soluble Mn(I) tricarbonyl diimine complex, [MnBr(4,4'-{Et2 O3 PCH2 }2 -2,2'-bipyridyl)(CO)3 ] ( 1 ), has been fully characterized, including single-crystal X-ray crystallography, and shown to reduce CO2 to CO following photosensitization by tetra( N -methyl-4-pyridyl)porphyrin Zn(II) tetrachloride [Zn(TMPyP)]Cl4 ( 2 ) under 625 nm irradiation. This is the first example of 2 employed as a photosensitizer for CO2 reduction. The incorporation of -P(O)(OEt)2 groups, decoupled from the core of the catalyst by a -CH2 - spacer, afforded water solubility without compromising the electronic properties of the catalyst. The photostability of the active Mn(I) catalyst over prolonged periods of irradiation with red light was confirmed by1 H and13 C{1 H} NMR spectroscopy. This first report on Mn(I) species as a homogeneous photocatalyst, working in water and under red light, illustrates further future prospects of intrinsically photounstable Mn(I) complexes as solar-driven catalysts in an aqueous environment.- Published
- 2022
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15. A Dinuclear Osmium(II) Complex Near-Infrared Nanoscopy Probe for Nuclear DNA.
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Dröge F, Noakes FF, Archer SA, Sreedharan S, Raza A, Robertson CC, MacNeil S, Haycock JW, Carson H, Meijer AJHM, Smythe CGW, Bernardino de la Serna J, Dietzek-Ivanšić B, and Thomas JA
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- Animals, Cattle, Cell Line, Tumor, Coordination Complexes chemical synthesis, Coordination Complexes toxicity, Humans, Luminescent Agents chemical synthesis, Luminescent Agents toxicity, Microscopy, Confocal, Osmium chemistry, Osmium toxicity, Coordination Complexes chemistry, DNA analysis, Luminescent Agents chemistry
- Abstract
With the aim of developing photostable near-infrared cell imaging probes, a convenient route to the synthesis of heteroleptic Os
II complexes containing the Os(TAP)2 fragment is reported. This method was used to synthesize the dinuclear OsII complex, [{Os(TAP)2 }2 tpphz]4+ (where tpphz = tetrapyrido[3,2-a:2',3'-c:3″,2''-h:2‴,3'''-j]phenazine and TAP = 1,4,5,8- tetraazaphenanthrene). Using a combination of resonance Raman and time-resolved absorption spectroscopy, as well as computational studies, the excited state dynamics of the new complex were dissected. These studies revealed that, although the complex has several close lying excited states, its near-infrared, NIR, emission (λmax = 780 nm) is due to a low-lying Os → TAP based3 MCLT state. Cell-based studies revealed that unlike its RuII analogue, the new complex is neither cytotoxic nor photocytotoxic. However, as it is highly photostable as well as live-cell permeant and displays NIR luminescence within the biological optical window, its properties make it an ideal probe for optical microscopy, demonstrated by its use as a super-resolution NIR STED probe for nuclear DNA.- Published
- 2021
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