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1.
Mol Cell ; 61(1): 161-9, 2016 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-26626482

RESUMO

G quadruplexes (G4s) can present potent blocks to DNA replication. Accurate and timely replication of G4s in vertebrates requires multiple specialized DNA helicases and polymerases to prevent genetic and epigenetic instability. Here we report that PrimPol, a recently described primase-polymerase (PrimPol), plays a crucial role in the bypass of leading strand G4 structures. While PrimPol is unable to directly replicate G4s, it can bind and reprime downstream of these structures. Disruption of either the catalytic activity or zinc-finger of PrimPol results in extreme G4-dependent epigenetic instability at the BU-1 locus in avian DT40 cells, indicative of extensive uncoupling of the replicative helicase and polymerase. Together, these observations implicate PrimPol in promoting restart of DNA synthesis downstream of, but closely coupled to, G4 replication impediments.


Assuntos
Proteínas Aviárias/metabolismo , DNA Primase/metabolismo , Replicação do DNA , DNA Polimerase Dirigida por DNA/metabolismo , DNA/biossíntese , Quadruplex G , Enzimas Multifuncionais/metabolismo , Animais , Proteínas Aviárias/genética , Sequência de Bases , Linhagem Celular , Galinhas , Montagem e Desmontagem da Cromatina , DNA/química , DNA Primase/genética , DNA Polimerase Dirigida por DNA/genética , Epigênese Genética , Instabilidade Genômica , Histonas/metabolismo , Dados de Sequência Molecular , Enzimas Multifuncionais/genética , Transfecção
2.
J Craniofac Surg ; 35(1): 96-103, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38294298

RESUMO

The Craniofacial Collaboration (CC-UK) is a shared initiative across the Psychology teams attached to 4 highly specialized craniofacial centers in the United Kingdom. The CC-UK aims to address key limitations in the existing craniofacial literature by analyzing data for homogenous samples of children with craniosynostosis. This article presents the fifth wave of CC-UK data collection, focused on 7- and 10-year olds who have undergone primary corrective surgery for metopic synostosis (MS). Data for children with sagittal synostosis and MS have previously been presented at 3 and 5 years. This paper continues to build on this with consideration to older age groups, presenting the first CC-UK analysis of cognitive assessment data using the Wechsler Abbreviated Scale of Intelligence-Second Edition. Results show that the majority of children with MS fall within the average ranges across behavioral and neurodevelopmental domains. However, several domains indicated a trend of heightened concern when compared with normative data, particularly for parent-reported outcomes, suggesting that there may be some subtle difficulties for children with MS. Consideration of how these findings compare with that of previous CC-UK analyses is explored. Further, implications for clinical practice and future research are considered, with the need for longitudinal analyses, as well as data from multiple perspectives (eg, school, parents, and self) at older age points to establish patterns over time. Through collaboration across the highly specialized craniofacial centers, the CC-UK hopes to work toward this goal moving forward.


Assuntos
Craniossinostoses , Criança , Humanos , Idoso , Craniossinostoses/cirurgia , Coleta de Dados , Ácido Dioctil Sulfossuccínico , Pais , Reino Unido
3.
J Craniofac Surg ; 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38949257

RESUMO

The Craniofacial Collaboration UK (CC-UK) protocol is a shared agreement across the 4 UK Highly Specialist Craniofacial Centres (HSCCs) to conduct robust neurodevelopmental and psychosocial clinical screening for children with craniosynostosis. This agreement allows for the analysis of outcomes of a homogenous sample of children with single suture craniosynostosis (SSC), a frequent limitation of the existing research. The current study is the latest analysis of CC-UK data on behavioral, cognitive, and psychosocial outcomes. The focus of this analysis is 7- and 10-year-olds with nonsyndromic sagittal synostosis (SS) who have undergone primary corrective surgery and completed routine clinical screening at 1 of the 4 HSCCs since the introduction of the CC-UK protocol. Due to changes in clinical pathways, only data from 3 HSCCs is included to preserve homogeneity. Results show that the majority of children with SS fall within the average range across behavioral and neurodevelopmental domains. A notable exception was a task involving perceptual reasoning and visuomotor skills (Block Design). Although this difference was small and the mean score remained within the average range, it suggests some increased risk of subtle difficulty with such skills for children with SS. Across other measures, there was no consistent evidence of any significantly increased risk of poorer outcomes, in line with findings of previous CC-UK papers. Understanding the psychological phenotype of SS is a key research priority for parents and clinicians, and the current study is another step toward achieving this goal.

4.
J Craniofac Surg ; 34(3): 855-859, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-36329005

RESUMO

The Craniofacial Collaboration (CC-UK) was setup in 2015 as a joint initiative between the Psychology teams attached to the 4 highly specialized craniofacial centers in the United Kingdom. The CC-UK aims to address key limitations in the existing craniofacial literature by applying strict exclusion criteria and collating clinical data on a homogenous sample of children. This article reports the fourth wave of data collection from the CC-UK, with the analysis of developmental and behavioral outcomes for children with metopic synostosis at 5 years old. Previous data for sagittal synostosis at 3 and 5 years, and metopic synostosis at 3 years, have been presented. This paper offers the first analysis of developmental and behavioral parent-report measures at school age for metopic synostosis. All children in the current data set had primary corrective surgery. Findings highlight similar patterns to that of previous research among children with single-suture craniosynostosis, as well as earlier CC-UK analyses, with the majority falling within 1 standard deviation of the normative mean. However, differences across key behavioral and emotional domains, with some areas reporting heightened concerns compared with those detected among sagittal groups, may suggest that subtle differences between individual diagnostic groups are present. This further highlights the importance of utilizing homogenous samples within the field of craniofacial research. To further build upon this work, and to provide a greater understanding of how these difficulties and concerns may develop, or diminish, over time, further consideration to longitudinal outcomes is needed for individual diagnostic groups. Through this collaboration, the authors seek to achieve this goal in their future work.


Assuntos
Craniossinostoses , Humanos , Lactente , Pré-Escolar , Craniossinostoses/cirurgia , Craniossinostoses/diagnóstico , Suturas Cranianas , Ossos Faciais , Emoções , Procedimentos Neurocirúrgicos
5.
Anal Chem ; 94(51): 17810-17818, 2022 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-36520113

RESUMO

Liquid chromatography (LC)-mass spectrometry (MS)/MS lipidomic normalization is generally performed by equalizing pre-extraction sample materials or via DNA or protein pre-quantitation methods, which have known measurement inaccuracies. We propose the use of the sulfo-phospho-vanillin assay (SPVA), a total lipid colorimetric analysis, as a pre-quantitation method to normalize lipids in lipidomic LC-MS/MS applications. The assay has been applied to a 300 µL well volume in a 96-well plate and tested using Avanti total lipid standards of porcine brain and E. coli. Assay parameters for lipid sample volume, sulfuric acid, vanillin/phosphoric acid, post-reaction incubation time, and wavelength are optimized for robust application to biologically sourced lipid samples. Standard test samples were prepared using three concentrations covering approximately 100 µg/mL range. The optimized assay yielded test sample errors less than 10%, indicating a precise and accurate assay performance. The test samples were then analyzed by LC-MS/MS and normalized using SPVA pre-quantitation and pseudo-mass normalization. The detected lipids showed smaller standard deviations and greater relative concentration differences compared to the pseudo-mass normalized lipids, showing promise as a normalization method.


Assuntos
Lipidômica , Espectrometria de Massas em Tandem , Animais , Suínos , Cromatografia Líquida/métodos , Espectrometria de Massas em Tandem/métodos , Escherichia coli , Lipídeos/análise
6.
Exp Dermatol ; 31(11): 1800-1809, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35851722

RESUMO

The physiology and pathology of the skin are influenced by daily oscillations driven by a master clock located in the brain, and peripheral clocks in individual cells. The pathogenesis of psoriasis is circadian-rhythmic, with flares of disease and symptoms such as itch typically being worse in the evening/night-time. Patients with psoriasis have changes in circadian oscillations of blood pressure and heart rate, supporting wider circadian disruption. In addition, shift work, a circadian misalignment challenge, is associated with psoriasis. These features may be due to underlying circadian control of key effector elements known to be relevant in psoriasis such as cell cycle, proliferation, apoptosis and inflammation. Indeed, peripheral clock pathology may lead to hyperproliferation of keratinocytes in the basal layers, insufficient apoptosis of differentiating keratinocytes in psoriatic epidermis, dysregulation of skin-resident and migratory immune cells and modulation of angiogenesis through circadian oscillation of vascular endothelial growth factor A (VEGF-A) in epidermal keratinocytes. Chronotherapeutic effects of topical steroids and topical vitamin D analogues have been reported, suggesting that knowledge of circadian phase may improve the efficacy, and therapeutic index of treatments for psoriasis. In this viewpoint essay, we review the current literature on circadian disruption in psoriasis. We explore the hypothesis that psoriasis is circadian-driven. We also suggest that investigation of the circadian components specific to psoriasis and that the in vitro investigation of circadian regulation of psoriasis will contribute to the development of a novel chronotherapeutic treatment strategy for personalised psoriasis management. We also propose that circadian oscillations of VEGF-A offer an opportunity to enhance the efficacy and tolerability of a novel anti-VEGF-A therapeutic approach, through the timed delivery of anti-VEGF-A drugs.


Assuntos
Ritmo Circadiano , Psoríase , Humanos , Fator A de Crescimento do Endotélio Vascular/metabolismo , Cronoterapia , Psoríase/metabolismo , Pele/metabolismo
7.
Anal Chem ; 93(6): 3154-3162, 2021 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-33534538

RESUMO

Glycosphingolipids (GSLs) play a key role in various biological and pathological events. Thus, determination of the complete GSL compositions in human tissues is essential for comparative and functional studies of GSLs. In this work, a new strategy was developed for GSL characterization and glycolipidomics analysis based on two-stage matching of experimental and reference MS/MS spectra. In the first stage, carbohydrate fragments, which contain only glycans and thus are conserved within a GSL species, are directly matched to yield a species identification. In the second stage, glycolipid fragments from the matched GSL species, which contain both the lipid and glycans and thus shift due to lipid structural changes, are treated according to lipid rule-based matching to characterize the lipid compositions. This new strategy uses the whole spectrum for GSL characterization. Furthermore, simple databases containing only a single lipid form per GSL species can be utilized to identify multiple GSL lipid forms. It is expected that this method will help accelerate glycolipidomics analysis and disclose new and diverse lipid forms of GSLs.


Assuntos
Glicoesfingolipídeos , Espectrometria de Massas em Tandem , Cromatografia Líquida , Humanos , Lipídeos , Polissacarídeos
8.
Mol Cell ; 52(4): 566-73, 2013 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-24267451

RESUMO

DNA damage can stall the DNA replication machinery, leading to genomic instability. Thus, numerous mechanisms exist to complete genome duplication in the absence of a pristine DNA template, but identification of the enzymes involved remains incomplete. Here, we establish that Primase-Polymerase (PrimPol; CCDC111), an archaeal-eukaryotic primase (AEP) in eukaryotic cells, is involved in chromosomal DNA replication. PrimPol is required for replication fork progression on ultraviolet (UV) light-damaged DNA templates, possibly mediated by its ability to catalyze translesion synthesis (TLS) of these lesions. This PrimPol UV lesion bypass pathway is not epistatic with the Pol η-dependent pathway and, as a consequence, protects xeroderma pigmentosum variant (XP-V) patient cells from UV-induced cytotoxicity. In addition, we establish that PrimPol is also required for efficient replication fork progression during an unperturbed S phase. These and other findings indicate that PrimPol is an important player in replication fork progression in eukaryotic cells.


Assuntos
Cromossomos Humanos/genética , Adutos de DNA/genética , DNA Primase/fisiologia , Replicação do DNA , DNA Polimerase Dirigida por DNA/fisiologia , Enzimas Multifuncionais/fisiologia , Sequência de Aminoácidos , Animais , Proliferação de Células , Sobrevivência Celular , Galinhas , Adutos de DNA/química , Adutos de DNA/metabolismo , Dano ao DNA , DNA Primase/química , DNA de Cadeia Simples/química , DNA Polimerase Dirigida por DNA/química , Pontos de Checagem da Fase G2 do Ciclo Celular , Técnicas de Silenciamento de Genes , Células HEK293 , Humanos , Camundongos , Camundongos Knockout , Dados de Sequência Molecular , Enzimas Multifuncionais/química , Raios Ultravioleta , Xenopus
9.
Nucleic Acids Res ; 47(8): 4026-4038, 2019 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-30715459

RESUMO

Eukaryotic Primase-Polymerase (PrimPol) is an enzyme that maintains efficient DNA duplication by repriming replication restart downstream of replicase stalling lesions and structures. To elucidate the cellular requirements for PrimPol in human cells, we generated PrimPol-deleted cell lines and show that it plays key roles in maintaining active replication in both the nucleus and mitochondrion, even in the absence of exogenous damage. Human cells lacking PrimPol exhibit delayed recovery after UV-C damage and increased mutation frequency, micronuclei and sister chromatin exchanges but are not sensitive to genotoxins. PrimPol is also required during mitochondrial replication, with PrimPol-deficient cells having increased mtDNA copy number but displaying a significant decrease in replication. Deletion of PrimPol in XPV cells, lacking functional polymerase Eta, causes an increase in DNA damage sensitivity and pronounced fork stalling after UV-C treatment. We show that, unlike canonical TLS polymerases, PrimPol is important for allowing active replication to proceed, even in the absence of exogenous damage, thus preventing the accumulation of excessive fork stalling and genetic mutations. Together, these findings highlight the importance of PrimPol for maintaining efficient DNA replication in unperturbed cells and its complementary roles, with Pol Eta, in damage tolerance in human cells.


Assuntos
Núcleo Celular/efeitos da radiação , DNA Primase/genética , Replicação do DNA/efeitos da radiação , DNA Polimerase Dirigida por DNA/genética , DNA/genética , Mitocôndrias/efeitos da radiação , Enzimas Multifuncionais/genética , 4-Nitroquinolina-1-Óxido/farmacologia , Bleomicina/farmacologia , Linhagem Celular Transformada , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/genética , Cisplatino/farmacologia , DNA/efeitos dos fármacos , DNA/metabolismo , DNA Primase/deficiência , Replicação do DNA/efeitos dos fármacos , DNA Polimerase Dirigida por DNA/deficiência , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibroblastos/efeitos da radiação , Deleção de Genes , Humanos , Micronúcleos com Defeito Cromossômico/efeitos dos fármacos , Micronúcleos com Defeito Cromossômico/efeitos da radiação , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Enzimas Multifuncionais/deficiência , Mutagênicos/farmacologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteoblastos/efeitos da radiação , Quinolonas/farmacologia , Troca de Cromátide Irmã/efeitos dos fármacos , Troca de Cromátide Irmã/efeitos da radiação , Raios Ultravioleta/efeitos adversos
10.
J Am Chem Soc ; 142(32): 13645-13650, 2020 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-32702987

RESUMO

The nematode Caenorhabditis elegans produces a broad family of pheromones, known as the ascarosides, that are modified with a variety of groups derived from primary metabolism. These modifications are essential for the diverse activities of the ascarosides in development and various behaviors, including attraction, aggregation, avoidance, and foraging. The mechanism by which these different groups are added to the ascarosides is poorly understood. Here, we identify a family of over 30 enzymes, which are homologous to mammalian carboxylesterase (CES) enzymes, and show that a number of these enzymes are responsible for the selective addition of specific modifications to the ascarosides. Through stable isotope feeding experiments, we demonstrate the in vivo activity of the CES-like enzymes and provide direct evidence that the acyl-CoA synthetase ACS-7, which was previously implicated in the attachment of certain modifications to the ascarosides in C. elegans, instead activates the side chains of certain ascarosides for shortening through ß-oxidation. Our data provide a key to the combinatorial logic that gives rise to different modified ascarosides, which should greatly facilitate the exploration of the specific biological functions of these pheromones in the worm.


Assuntos
Caenorhabditis elegans/enzimologia , Carboxilesterase/metabolismo , Coenzima A Ligases/metabolismo , Animais , Glicolipídeos/biossíntese , Glicolipídeos/química , Estrutura Molecular
11.
Cytotherapy ; 22(12): 762-771, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32828673

RESUMO

BACKGROUND AIMS: Mesenchymal stromal cells (MSCs) isolated from various tissues are under investigation as cellular therapeutics in a wide range of diseases. It is appreciated that the basic biological functions of MSCs vary depending on tissue source. However, in-depth comparative analyses between MSCs isolated from different tissue sources under Good Manufacturing Practice (GMP) conditions are lacking. Human clinical-grade low-purity islet (LPI) fractions are generated as a byproduct of islet isolation for transplantation. MSC isolates were derived from LPI fractions with the aim of performing a systematic, standardized comparative analysis of these cells with clinically relevant bone marrow-derived MSCs (BM MSCs). METHODS: MSC isolates were derived from LPI fractions and expanded in platelet lysate-supplemented medium or in commercially available xenogeneic-free medium. Doubling rate, phenotype, differentiation potential, gene expression, protein production and immunomodulatory capacity of LPIs were compared with those of BM MSCs. RESULTS: MSCs can be readily derived in vitro from non-transplanted fractions resulting from islet cell processing (i.e., LPI MSCs). LPI MSCs grow stably in serum-free or platelet lysate-supplemented media and demonstrate in vitro self-renewal, as measured by colony-forming unit assay. LPI MSCs express patterns of chemokines and pro-regenerative factors similar to those of BM MSCs and, importantly, are equally able to attract immune cells in vitro and in vivo and suppress T-cell proliferation in vitro. Additionally, LPI MSCs can be expanded to therapeutically relevant doses at low passage under GMP conditions. CONCLUSIONS: LPI MSCs represent an alternative source of GMP MSCs with functions comparable to BM MSCs.


Assuntos
Células da Medula Óssea/citologia , Técnicas de Cultura de Células/métodos , Imunidade , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/imunologia , Neovascularização Fisiológica , Pâncreas/citologia , Biomarcadores/metabolismo , Diferenciação Celular , Proliferação de Células , Forma Celular , Células Cultivadas , Ensaio de Unidades Formadoras de Colônias , Humanos , Imunomodulação , Interferon gama/metabolismo , Medicina Regenerativa , Linfócitos T/citologia
12.
Proc Natl Acad Sci U S A ; 113(30): E4276-85, 2016 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-27402764

RESUMO

The genetic information in mammalian mitochondrial DNA is densely packed; there are no introns and only one sizeable noncoding, or control, region containing key cis-elements for its replication and expression. Many molecules of mitochondrial DNA bear a third strand of DNA, known as "7S DNA," which forms a displacement (D-) loop in the control region. Here we show that many other molecules contain RNA as a third strand. The RNA of these R-loops maps to the control region of the mitochondrial DNA and is complementary to 7S DNA. Ribonuclease H1 is essential for mitochondrial DNA replication; it degrades RNA hybridized to DNA, so the R-loop is a potential substrate. In cells with a pathological variant of ribonuclease H1 associated with mitochondrial disease, R-loops are of low abundance, and there is mitochondrial DNA aggregation. These findings implicate ribonuclease H1 and RNA in the physical segregation of mitochondrial DNA, perturbation of which represents a previously unidentified disease mechanism.


Assuntos
DNA Mitocondrial/genética , Mitocôndrias/genética , Mutação , Ribonuclease H/genética , Animais , Linhagem Celular Tumoral , Células Cultivadas , Replicação do DNA , DNA Mitocondrial/química , DNA Mitocondrial/metabolismo , Feminino , Células HEK293 , Humanos , Masculino , Camundongos , Mitocôndrias/metabolismo , Doenças Mitocondriais/genética , Doenças Mitocondriais/metabolismo , Conformação de Ácido Nucleico , Ribonuclease H/metabolismo
13.
Nucleic Acids Res ; 44(7): 3317-29, 2016 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-26984527

RESUMO

Translesion synthesis (TLS) employs specialized DNA polymerases to bypass replication fork stalling lesions. PrimPol was recently identified as a TLS primase and polymerase involved in DNA damage tolerance. Here, we identify a novel PrimPol binding partner, PolDIP2, and describe how it regulates PrimPol's enzymatic activities. PolDIP2 stimulates the polymerase activity of PrimPol, enhancing both its capacity to bind DNA and the processivity of the catalytic domain. In addition, PolDIP2 stimulates both the efficiency and error-free bypass of 8-oxo-7,8-dihydrodeoxyguanosine (8-oxoG) lesions by PrimPol. We show that PolDIP2 binds to PrimPol's catalytic domain and identify potential binding sites. Finally, we demonstrate that depletion of PolDIP2 in human cells causes a decrease in replication fork rates, similar to that observed in PrimPol(-/-)cells. However, depletion of PolDIP2 in PrimPol(-/-)cells does not produce a further decrease in replication fork rates. Together, these findings establish that PolDIP2 can regulate the TLS polymerase and primer extension activities of PrimPol, further enhancing our understanding of the roles of PolDIP2 and PrimPol in eukaryotic DNA damage tolerance.


Assuntos
Dano ao DNA , DNA Primase/metabolismo , DNA Polimerase Dirigida por DNA/metabolismo , Enzimas Multifuncionais/metabolismo , Proteínas Nucleares/metabolismo , Células Cultivadas , DNA/metabolismo , DNA Primase/antagonistas & inibidores , Replicação do DNA , Proteínas de Ligação a DNA/metabolismo , Guanina/análogos & derivados , Humanos , Enzimas Multifuncionais/antagonistas & inibidores , Antígeno Nuclear de Célula em Proliferação/metabolismo
14.
Biochem Soc Trans ; 45(2): 513-529, 2017 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-28408491

RESUMO

PrimPol, (primase-polymerase), the most recently identified eukaryotic polymerase, has roles in both nuclear and mitochondrial DNA maintenance. PrimPol is capable of acting as a DNA polymerase, with the ability to extend primers and also bypass a variety of oxidative and photolesions. In addition, PrimPol also functions as a primase, catalysing the preferential formation of DNA primers in a zinc finger-dependent manner. Although PrimPol's catalytic activities have been uncovered in vitro, we still know little about how and why it is targeted to the mitochondrion and what its key roles are in the maintenance of this multicopy DNA molecule. Unlike nuclear DNA, the mammalian mitochondrial genome is circular and the organelle has many unique proteins essential for its maintenance, presenting a differing environment within which PrimPol must function. Here, we discuss what is currently known about the mechanisms of DNA replication in the mitochondrion, the proteins that carry out these processes and how PrimPol is likely to be involved in assisting this vital cellular process.


Assuntos
DNA Primase/metabolismo , Replicação do DNA , DNA Mitocondrial/genética , DNA Polimerase Dirigida por DNA/metabolismo , Enzimas Multifuncionais/metabolismo , Animais , Núcleo Celular/genética , DNA Primase/genética , DNA Polimerase Dirigida por DNA/genética , Humanos , Mitocôndrias/genética , Enzimas Multifuncionais/genética , Mutação
15.
Cytotherapy ; 19(9): 1113-1124, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28673774

RESUMO

BACKGROUND AIMS: Autologous macrophage therapy represents a potentially significant therapeutic advance for the treatment of severe progressive liver cirrhosis. Administration of macrophages has been shown to reduce inflammation and drive fibrotic scar breakdown and tissue repair in relevant models. This therapeutic approach is being assessed for safety and feasibility in a first-in-human trial (MAcrophages Therapy for liver CirrHosis [MATCH] trial). METHODS: We outline the development and validation phases of GMP production. This includes use of the CliniMACS Prodigy cell sorting system to isolate CD14+ cells; optimizing macrophage culture conditions, assessing cellular identity, product purity, functional capability and determining the stability of the final cell product. RESULTS: The GMP-compliant macrophage products have a high level of purity and viability, and have a consistent phenotypic profile, expressing high levels of mature macrophage markers 25F9 and CD206 and low levels of CCR2. The macrophages demonstrate effective phagocytic capacity, are constitutively oriented to an anti-inflammatory profile and remain responsive to cytokine and TLR stimulation. The process validation shows that the cell product in excipient is remarkably robust, consistently passing the viability and phenotypic release criteria up to 48 hours after harvest. CONCLUSIONS: This is the first report of validation of a large-scale, fully Good Manufacturing Practice-compliant, autologous macrophage cell therapy product for the potential treatment of cirrhosis. Phenotypic and functional assays confirm that these cells remain functionally viable for up to 48 h, allowing significant flexibility in administration to patients.


Assuntos
Técnicas de Cultura de Células/métodos , Cirrose Hepática/terapia , Macrófagos/citologia , Fagocitose/fisiologia , Biomarcadores/metabolismo , Técnicas de Cultura de Células/normas , Separação Celular/métodos , Separação Celular/normas , Transplante de Células/métodos , Citocinas/farmacologia , Feminino , Humanos , Lectinas Tipo C/metabolismo , Receptores de Lipopolissacarídeos/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/fisiologia , Receptor de Manose , Lectinas de Ligação a Manose/metabolismo , Monócitos/citologia , Receptores CCR2/metabolismo , Receptores de Superfície Celular/metabolismo
16.
Nucleic Acids Res ; 43(2): 1056-68, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25550423

RESUMO

PrimPol is a recently identified polymerase involved in eukaryotic DNA damage tolerance, employed in both re-priming and translesion synthesis mechanisms to bypass nuclear and mitochondrial DNA lesions. In this report, we investigate how the enzymatic activities of human PrimPol are regulated. We show that, unlike other TLS polymerases, PrimPol is not stimulated by PCNA and does not interact with it in vivo. We identify that PrimPol interacts with both of the major single-strand binding proteins, RPA and mtSSB in vivo. Using NMR spectroscopy, we characterize the domains responsible for the PrimPol-RPA interaction, revealing that PrimPol binds directly to the N-terminal domain of RPA70. In contrast to the established role of SSBs in stimulating replicative polymerases, we find that SSBs significantly limit the primase and polymerase activities of PrimPol. To identify the requirement for this regulation, we employed two forward mutation assays to characterize PrimPol's replication fidelity. We find that PrimPol is a mutagenic polymerase, with a unique error specificity that is highly biased towards insertion-deletion errors. Given the error-prone disposition of PrimPol, we propose a mechanism whereby SSBs greatly restrict the contribution of this enzyme to DNA replication at stalled forks, thus reducing the mutagenic potential of PrimPol during genome replication.


Assuntos
DNA Primase/metabolismo , Proteínas de Ligação a DNA/metabolismo , DNA Polimerase Dirigida por DNA/metabolismo , Proteínas Mitocondriais/metabolismo , Enzimas Multifuncionais/metabolismo , Proteína de Replicação A/metabolismo , Primers do DNA/biossíntese , Replicação do DNA , Humanos , Mutagênese , Antígeno Nuclear de Célula em Proliferação/metabolismo , Domínios e Motivos de Interação entre Proteínas , Proteína de Replicação A/química
17.
Nucleic Acids Res ; 42(19): 12102-11, 2014 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-25262353

RESUMO

PrimPol is a primase-polymerase found in humans, and other eukaryotes, involved in bypassing lesions encountered during DNA replication. PrimPol employs both translesion synthesis and repriming mechanisms to facilitate lesion bypass by the replisome. PrimPol has been reported to be a potential susceptibility gene associated with the development of myopia. Mutation of tyrosine 89 to aspartic acid (PrimPolY89D) has been identified in a number of cases of high myopia, implicating it in the aetiology of this disorder. Here, we examined whether this mutation resulted in any changes in the molecular and cellular activities associated with human PrimPol. We show that PrimPolY89D has a striking decrease in primase and polymerase activities. The hydrophobic ring of tyrosine is important for retaining wild-type extension activity. We also demonstrate that the decreased activity of PrimPolY89D is associated with reduced affinities for DNA and nucleotides, resulting in diminished catalytic efficiency. Although the structure and stability of PrimPolY89D is altered, its fidelity remains unchanged. This mutation also reduces cell viability after DNA damage and significantly slows replication fork rates in vivo. Together, these findings establish that the major DNA replication defect associated with this PrimPol mutant is likely to contribute to the onset of high myopia.


Assuntos
DNA Primase/genética , Replicação do DNA , DNA Polimerase Dirigida por DNA/genética , Enzimas Multifuncionais/genética , Miopia/genética , Mutação Puntual , DNA/metabolismo , DNA Primase/química , DNA Primase/metabolismo , DNA Polimerase Dirigida por DNA/química , DNA Polimerase Dirigida por DNA/metabolismo , Humanos , Enzimas Multifuncionais/química , Enzimas Multifuncionais/metabolismo
18.
Nucleic Acids Res ; 42(9): 5830-45, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24682820

RESUMO

PrimPol is a primase-polymerase involved in nuclear and mitochondrial DNA replication in eukaryotic cells. Although PrimPol is predicted to possess an archaeo-eukaryotic primase and a UL52-like zinc finger domain, the role of these domains has not been established. Here, we report that the proposed zinc finger domain of human PrimPol binds zinc ions and is essential for maintaining primase activity. Although apparently dispensable for its polymerase activity, the zinc finger also regulates the processivity and fidelity of PrimPol's extension activities. When the zinc finger is disrupted, PrimPol becomes more promutagenic, has an altered translesion synthesis spectrum and is capable of faithfully bypassing cyclobutane pyrimidine dimer photolesions. PrimPol's polymerase domain binds to both single- and double-stranded DNA, whilst the zinc finger domain binds only to single-stranded DNA. We additionally report that although PrimPol's primase activity is required to restore wild-type replication fork rates in irradiated PrimPol-/- cells, polymerase activity is sufficient to maintain regular replisome progression in unperturbed cells. Together, these findings provide the first analysis of the molecular architecture of PrimPol, describing the activities associated with, and interplay between, its functional domains and defining the requirement for its primase and polymerase activities during nuclear DNA replication.


Assuntos
DNA Primase/química , DNA Polimerase Dirigida por DNA/química , Enzimas Multifuncionais/química , Animais , Domínio Catalítico , Linhagem Celular , DNA Primase/fisiologia , Reparo do DNA , Replicação do DNA , DNA Polimerase Dirigida por DNA/fisiologia , Ensaio de Desvio de Mobilidade Eletroforética , Humanos , Manganês/química , Enzimas Multifuncionais/fisiologia , Ligação Proteica , Proteínas de Xenopus/química , Zinco/química
19.
Chembiochem ; 16(5): 861-7, 2015 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-25688874

RESUMO

Antibody-like proteins selected from discovery platforms are preferentially functionalized by site-specific modification as this approach preserves the binding abilities and allows a side-by-side comparison of multiple conjugates. Here we present an enzymatic bioconjugation platform that targets the c-myc-tag peptide sequence (EQKLISEEDL) as a handle for the site-specific modification of antibody-like proteins. Microbial transglutaminase (MTGase) was exploited to form a stable isopeptide bond between the glutamine on the c-myc-tag and various primary-amine-functionalized substrates. We attached eight different functionalities to a c-myc-tagged antibody fragment and used these bioconjugates for downstream applications such as protein multimerization, immobilization on surfaces, fluorescence microscopy, fluorescence-activated cell sorting, and in vivo nuclear imaging. The results demonstrate the versatility of our conjugation strategy for transforming a c-myc-tagged protein into any desired probe.


Assuntos
Anticorpos/química , Anticorpos/metabolismo , Neoplasias Experimentais/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Transglutaminases/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular , Feminino , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Humanos , Imunoconjugados/química , Imunoconjugados/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Camundongos SCID , Sondas Moleculares/química , Sondas Moleculares/metabolismo , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Recombinantes/metabolismo
20.
Cytotherapy ; 17(11): 1604-16, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26342993

RESUMO

BACKGROUND AIMS: Macrophages have complex roles in the liver. The aim of this study was to compare profiles of human monocyte-derived macrophages between controls and cirrhotic patients, to determine whether chronic inflammation affects precursor number or the phenotype, with the eventual aim to develop a cell therapy for cirrhosis. METHODS: Infusion of human macrophages in a murine liver fibrosis model demonstrated a decrease in markers of liver injury (alanine transaminase, bilirubin, aspartate transaminase) and fibrosis (transforming growth factor-ß, α-smooth muscle actin, phosphatidylserine receptor) and an increase in markers of liver regeneration (matrix metalloproteinases [MMP]-9, MMP-12 and TNF-related weak inducer of apoptosis). CD14+ monocytes were then isolated from controls. Monocytes were matured into macrophages for 7 days using a Good Manufacturing Practice-compatible technique. RESULTS: There was no significant difference between the mean number of CD14+ monocytes isolated from cirrhotic patients (n = 9) and controls (n = 10); 2.8 ± SEM 0.54 × 10(8) and 2.5 ± 0.56 × 10(8), respectively. The mean yield of mature macrophages cultured was also not significantly different between cirrhotic patients and controls (0.9 × 10(8) ± 0.38 × 10(8), with more than 90% viability and 0.65 × 10(8) ± 0.16 × 10(8), respectively. Maturation to macrophages resulted in up-regulation of a number of genes (MMP-9, CCL2, interleukin [IL]-10 and TNF-related weak inducer of apoptosis). A cytokine and chemokine polymerase chain reaction array, comparing the control and cirrhotic macrophages, revealed no statistically significant differences. CONCLUSIONS: Macrophages can be differentiated from cirrhotic patients' apheresis-derived CD14 monocytes and develop the same pro-resolution phenotype as control macrophages, indicating their suitability for clinical therapy.


Assuntos
Cirrose Hepática/patologia , Macrófagos/fisiologia , Idoso , Animais , Estudos de Casos e Controles , Diferenciação Celular/imunologia , Diferenciação Celular/fisiologia , Células Cultivadas , Quimiocinas/genética , Estudos de Coortes , Citocinas/genética , Modelos Animais de Doenças , Feminino , Humanos , Receptores de Lipopolissacarídeos/metabolismo , Cirrose Hepática/induzido quimicamente , Cirrose Hepática/terapia , Regeneração Hepática , Macrófagos/metabolismo , Masculino , Camundongos Endogâmicos NOD , Pessoa de Meia-Idade , Monócitos/citologia , Monócitos/patologia
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