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1.
Mol Cell ; 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-39032490

RESUMO

INTS11 and CPSF73 are metal-dependent endonucleases for Integrator and pre-mRNA 3'-end processing, respectively. Here, we show that the INTS11 binding partner BRAT1/CG7044, a factor important for neuronal fitness, stabilizes INTS11 in the cytoplasm and is required for Integrator function in the nucleus. Loss of BRAT1 in neural organoids leads to transcriptomic disruption and precocious expression of neurogenesis-driving transcription factors. The structures of the human INTS9-INTS11-BRAT1 and Drosophila dIntS11-CG7044 complexes reveal that the conserved C terminus of BRAT1/CG7044 is captured in the active site of INTS11, with a cysteine residue directly coordinating the metal ions. Inspired by these observations, we find that UBE3D is a binding partner for CPSF73, and UBE3D likely also uses a conserved cysteine residue to directly coordinate the active site metal ions. Our studies have revealed binding partners for INTS11 and CPSF73 that behave like cytoplasmic chaperones with a conserved impact on the nuclear functions of these enzymes.

2.
Mol Cell ; 80(2): 345-358.e9, 2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-32966759

RESUMO

Efficient release of promoter-proximally paused RNA Pol II into productive elongation is essential for gene expression. Recently, we reported that the Integrator complex can bind paused RNA Pol II and drive premature transcription termination, potently attenuating the activity of target genes. Premature termination requires RNA cleavage by the endonuclease subunit of Integrator, but the roles of other Integrator subunits in gene regulation have yet to be elucidated. Here we report that Integrator subunit 8 (IntS8) is critical for transcription repression and required for association with protein phosphatase 2A (PP2A). We find that Integrator-bound PP2A dephosphorylates the RNA Pol II C-terminal domain and Spt5, preventing the transition to productive elongation. Thus, blocking PP2A association with Integrator stimulates pause release and gene activity. These results reveal a second catalytic function associated with Integrator-mediated transcription termination and indicate that control of productive elongation involves active competition between transcriptional kinases and phosphatases.


Assuntos
Proteínas de Drosophila/metabolismo , Proteína Fosfatase 2/metabolismo , Subunidades Proteicas/metabolismo , Fatores de Transcrição/metabolismo , Terminação da Transcrição Genética , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Sequência Conservada , Proteínas de Drosophila/química , Drosophila melanogaster , Regulação da Expressão Gênica , Loci Gênicos , Humanos , Fosforilação , Regiões Promotoras Genéticas , Subunidades Proteicas/química , RNA Polimerase II/química , RNA Polimerase II/metabolismo , Transdução de Sinais , Especificidade por Substrato , Fatores de Transcrição/química
3.
RNA ; 30(7): 824-838, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38575347

RESUMO

Forkhead box P3 (FOXP3) is the master fate-determining transcription factor in regulatory T (Treg) cells and is essential for their development, function, and homeostasis. Mutations in FOXP3 cause immunodysregulation polyendocrinopathy enteropathy X-linked (IPEX) syndrome, and aberrant expression of FOXP3 has been implicated in other diseases such as multiple sclerosis and cancer. We previously demonstrated that pre-mRNA splicing of FOXP3 RNAs is highly sensitive to levels of DExD-box polypeptide 39B (DDX39B), and here we investigate the mechanism of this sensitivity. FOXP3 introns have cytidine (C)-rich/uridine (U)-poor polypyrimidine (py) tracts that are responsible for their inefficient splicing and confer sensitivity to DDX39B. We show that there is a deficiency in the assembly of commitment complexes (CCs) on FOXP3 introns, which is consistent with the lower affinity of U2AF2 for C-rich/U-poor py tracts. Our data indicate an even stronger effect on the conversion of CCs to pre-spliceosomes. We propose that this is due to an altered conformation that U2AF2 adopts when it binds to C-rich/U-poor py tracts and that this conformation has a lower affinity for DDX39B. As a consequence, CCs assembled on FOXP3 introns are defective in recruiting DDX39B, and this leads to the inefficient assembly of pre-spliceosome complexes.


Assuntos
RNA Helicases DEAD-box , Fatores de Transcrição Forkhead , Íntrons , Splicing de RNA , Spliceossomos , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Humanos , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Spliceossomos/metabolismo , Spliceossomos/genética , Precursores de RNA/genética , Precursores de RNA/metabolismo
4.
Proc Natl Acad Sci U S A ; 120(28): e2220276120, 2023 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-37406091

RESUMO

Epithelial-to-mesenchymal transition (EMT) underlies immunosuppression, drug resistance, and metastasis in epithelial malignancies. However, the way in which EMT orchestrates disparate biological processes remains unclear. Here, we identify an EMT-activated vesicular trafficking network that coordinates promigratory focal adhesion dynamics with an immunosuppressive secretory program in lung adenocarcinoma (LUAD). The EMT-activating transcription factor ZEB1 drives exocytotic vesicular trafficking by relieving Rab6A, Rab8A, and guanine nucleotide exchange factors from miR-148a-dependent silencing, thereby facilitating MMP14-dependent focal adhesion turnover in LUAD cells and autotaxin-mediated CD8+ T cell exhaustion, indicating that cell-intrinsic and extrinsic processes are linked through a microRNA that coordinates vesicular trafficking networks. Blockade of ZEB1-dependent secretion reactivates antitumor immunity and negates resistance to PD-L1 immune checkpoint blockade, an important clinical problem in LUAD. Thus, EMT activates exocytotic Rabs to drive a secretory program that promotes invasion and immunosuppression in LUAD.


Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , MicroRNAs , Humanos , Linhagem Celular Tumoral , Homeobox 1 de Ligação a E-box em Dedo de Zinco/metabolismo , Neoplasias Pulmonares/genética , Adenocarcinoma de Pulmão/genética , MicroRNAs/genética , Terapia de Imunossupressão , Transição Epitelial-Mesenquimal/genética , Regulação Neoplásica da Expressão Gênica , Movimento Celular/genética
5.
Proc Natl Acad Sci U S A ; 119(12): e2114336119, 2022 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-35290121

RESUMO

The aryl hydrocarbon receptor nuclear translocator (ARNT) is a transcription factor present in immune cells as a long and short isoform, referred to as isoforms 1 and 3, respectively. However, investigation into potential ARNT isoform­specific immune functions is lacking despite the well-established heterodimerization requirement of ARNT with, and for the activity of, the aryl hydrocarbon receptor (AhR), a critical mediator of immune homeostasis. Here, using global and targeted transcriptomics analyses, we show that the relative ARNT isoform 1:3 ratio in human T cell lymphoma cells dictates the amplitude and direction of AhR target gene regulation. Specifically, shifting the ARNT isoform 1:3 ratio lower by suppressing isoform 1 enhances, or higher by suppressing isoform 3 abrogates, AhR responsiveness to ligand activation through preprograming a cellular genetic background that directs explicit gene expression patterns. Moreover, the fluctuations in gene expression patterns that accompany a decrease or increase in the ARNT isoform 1:3 ratio are associated with inflammation or immunosuppression, respectively. Molecular studies identified the unique casein kinase 2 (CK2) phosphorylation site within isoform 1 as an essential parameter to the mechanism of ARNT isoform­specific regulation of AhR signaling. Notably, CK2-mediated phosphorylation of ARNT isoform 1 is dependent on ligand-induced AhR nuclear translocation and is required for optimal AhR target gene regulation. These observations reveal ARNT as a central modulator of AhR activity predicated on the status of the ARNT isoform ratio and suggest that ARNT-based therapies are a viable option for tuning the immune system to target immune disorders.


Assuntos
Translocador Nuclear Receptor Aril Hidrocarboneto , Neoplasias , Translocador Nuclear Receptor Aril Hidrocarboneto/genética , Translocador Nuclear Receptor Aril Hidrocarboneto/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Humanos , Ligantes , Fosforilação , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Receptores de Hidrocarboneto Arílico/genética , Receptores de Hidrocarboneto Arílico/metabolismo , Linfócitos T/metabolismo
6.
Proc Natl Acad Sci U S A ; 119(32): e2205690119, 2022 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-35881779

RESUMO

The furin cleavage site (FCS), an unusual feature in the SARS-CoV-2 spike protein, has been spotlighted as a factor key to facilitating infection and pathogenesis by increasing spike processing. Similarly, the QTQTN motif directly upstream of the FCS is also an unusual feature for group 2B coronaviruses (CoVs). The QTQTN deletion has consistently been observed in in vitro cultured virus stocks and some clinical isolates. To determine whether the QTQTN motif is critical to SARS-CoV-2 replication and pathogenesis, we generated a mutant deleting the QTQTN motif (ΔQTQTN). Here, we report that the QTQTN deletion attenuates viral replication in respiratory cells in vitro and attenuates disease in vivo. The deletion results in a shortened, more rigid peptide loop that contains the FCS and is less accessible to host proteases, such as TMPRSS2. Thus, the deletion reduced the efficiency of spike processing and attenuates SARS-CoV-2 infection. Importantly, the QTQTN motif also contains residues that are glycosylated, and disruption of its glycosylation also attenuates virus replication in a TMPRSS2-dependent manner. Together, our results reveal that three aspects of the S1/S2 cleavage site-the FCS, loop length, and glycosylation-are required for efficient SARS-CoV-2 replication and pathogenesis.


Assuntos
COVID-19 , Furina , Proteólise , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Motivos de Aminoácidos/genética , Animais , COVID-19/virologia , Chlorocebus aethiops , Furina/química , Humanos , SARS-CoV-2/genética , SARS-CoV-2/fisiologia , Deleção de Sequência , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Células Vero , Replicação Viral/genética
7.
Proteomics ; : e2400036, 2024 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-39004851

RESUMO

Liquid chromatography-mass spectrometry (LC-MS) intact mass analysis and LC-MS/MS peptide mapping are decisional assays for developing biological drugs and other commercial protein products. Certain PTM types, such as truncation and oxidation, increase the difficulty of precise proteoform characterization owing to inherent limitations in peptide and intact protein analyses. Top-down MS (TDMS) can resolve this ambiguity via fragmentation of specific proteoforms. We leveraged the strengths of flow-programmed (fp) denaturing online buffer exchange (dOBE) chromatography, including robust automation, relatively high ESI sensitivity, and long MS/MS window time, to support a TDMS platform for industrial protein characterization. We tested data-dependent (DDA) and targeted strategies using 14 different MS/MS scan types featuring combinations of collisional- and electron-based fragmentation as well as proton transfer charge reduction. This large, focused dataset was processed using a new software platform, named TDAcquireX, that improves proteoform characterization through TDMS data aggregation. A DDA-based workflow provided objective identification of αLac truncation proteoforms with a two-termini clipping search. A targeted TDMS workflow facilitated the characterization of αLac oxidation positional isomers. This strategy relied on using sliding window-based fragment ion deconvolution to generate composite proteoform spectral match (cPrSM) results amenable to fragment noise filtering, which is a fundamental enhancement relevant to TDMS applications generally.

8.
J Biol Chem ; 299(4): 104586, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36889589

RESUMO

MDGAs (MAM domain-containing glycosylphosphatidylinositol anchors) are synaptic cell surface molecules that regulate the formation of trans-synaptic bridges between neurexins (NRXNs) and neuroligins (NLGNs), which promote synaptic development. Mutations in MDGAs are implicated in various neuropsychiatric diseases. MDGAs bind NLGNs in cis on the postsynaptic membrane and physically block NLGNs from binding to NRXNs. In crystal structures, the six immunoglobulin (Ig) and single fibronectin III domains of MDGA1 reveal a striking compact, triangular shape, both alone and in complex with NLGNs. Whether this unusual domain arrangement is required for biological function or other arrangements occur with different functional outcomes is unknown. Here, we show that WT MDGA1 can adopt both compact and extended 3D conformations that bind NLGN2. Designer mutants targeting strategic molecular elbows in MDGA1 alter the distribution of 3D conformations while leaving the binding affinity between soluble ectodomains of MDGA1 and NLGN2 intact. In contrast, in a cellular context, these mutants result in unique combinations of functional consequences, including altered binding to NLGN2, decreased capacity to conceal NLGN2 from NRXN1ß, and/or suppressed NLGN2-mediated inhibitory presynaptic differentiation, despite the mutations being located far from the MDGA1-NLGN2 interaction site. Thus, the 3D conformation of the entire MDGA1 ectodomain appears critical for its function, and its NLGN-binding site on Ig1-Ig2 is not independent of the rest of the molecule. As a result, global 3D conformational changes to the MDGA1 ectodomain via strategic elbows may form a molecular mechanism to regulate MDGA1 action within the synaptic cleft.


Assuntos
Moléculas de Adesão de Célula Nervosa , Sinapses , Moléculas de Adesão de Célula Nervosa/genética , Moléculas de Adesão de Célula Nervosa/metabolismo , Sinapses/metabolismo , Sítios de Ligação , Imunoglobulinas/genética , Imunoglobulinas/metabolismo , Conformação Molecular , Moléculas de Adesão Celular Neuronais/genética , Moléculas de Adesão Celular Neuronais/metabolismo
9.
Nucleic Acids Res ; 50(9): 5313-5334, 2022 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-35544276

RESUMO

Alternative splicing is critical for development; however, its role in the specification of the three embryonic germ layers is poorly understood. By performing RNA-Seq on human embryonic stem cells (hESCs) and derived definitive endoderm, cardiac mesoderm, and ectoderm cell lineages, we detect distinct alternative splicing programs associated with each lineage. The most prominent splicing program differences are observed between definitive endoderm and cardiac mesoderm. Integrative multi-omics analyses link each program with lineage-enriched RNA binding protein regulators, and further suggest a widespread role for Quaking (QKI) in the specification of cardiac mesoderm. Remarkably, knockout of QKI disrupts the cardiac mesoderm-associated alternative splicing program and formation of myocytes. These changes arise in part through reduced expression of BIN1 splice variants linked to cardiac development. Mechanistically, we find that QKI represses inclusion of exon 7 in BIN1 pre-mRNA via an exonic ACUAA motif, and this is concomitant with intron removal and cleavage from chromatin. Collectively, our results uncover alternative splicing programs associated with the three germ lineages and demonstrate an important role for QKI in the formation of cardiac mesoderm.


Assuntos
Processamento Alternativo , Linhagem da Célula , Camadas Germinativas , Proteínas de Ligação a RNA/metabolismo , Diferenciação Celular , Endoderma , Coração , Humanos , Mesoderma
10.
Nucleic Acids Res ; 50(16): 9548-9567, 2022 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-36039764

RESUMO

The AP1 transcription factor ΔFOSB, a splice variant of FOSB, accumulates in the brain in response to chronic insults such as exposure to drugs of abuse, depression, Alzheimer's disease and tardive dyskinesias, and mediates subsequent long-term neuroadaptations. ΔFOSB forms heterodimers with other AP1 transcription factors, e.g. JUND, that bind DNA under control of a putative cysteine-based redox switch. Here, we reveal the structural basis of the redox switch by determining a key missing crystal structure in a trio, the ΔFOSB/JUND bZIP domains in the reduced, DNA-free form. Screening a cysteine-focused library containing 3200 thiol-reactive compounds, we identify specific compounds that target the redox switch, validate their activity biochemically and in cell-based assays, and show that they are well tolerated in different cell lines despite their general potential to bind to cysteines covalently. A crystal structure of the ΔFOSB/JUND bZIP domains in complex with a redox-switch-targeting compound reveals a deep compound-binding pocket near the DNA-binding site. We demonstrate that ΔFOSB, and potentially other, related AP1 transcription factors, can be targeted specifically and discriminately by exploiting unique structural features such as the redox switch and the binding partner to modulate biological function despite these proteins previously being thought to be undruggable.


Assuntos
Cisteína , Proteínas Proto-Oncogênicas c-fos , Proteínas Proto-Oncogênicas c-fos/metabolismo , Cisteína/genética , Cisteína/metabolismo , Regulação da Expressão Gênica , DNA/genética , DNA/metabolismo , Oxirredução , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismo
11.
Acta Neuropathol ; 145(3): 303-324, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36538112

RESUMO

Individuals at distinct stages of Alzheimer's disease (AD) show abnormal electroencephalographic activity, which has been linked to network hyperexcitability and cognitive decline. However, whether pro-excitatory changes at the synaptic level are observed in brain areas affected early in AD, and if they are emergent in MCI, is not clearly known. Equally important, it is not known whether global synaptic E/I imbalances correlate with the severity of cognitive impairment in the continuum of AD. Measuring the amplitude of ion currents of human excitatory and inhibitory synaptic receptors microtransplanted from the hippocampus and temporal cortex of cognitively normal, mildly cognitively impaired and AD individuals into surrogate cells, we found regional differences in pro-excitatory shifts of the excitatory to inhibitory (E/I) current ratio that correlates positively with toxic proteins and degree of pathology, and impinges negatively on cognitive performance scores. Using these data with electrophysiologically anchored analysis of the synapto-proteome in the same individuals, we identified a group of proteins sustaining synaptic function and those related to synaptic toxicity. We also found an uncoupling between the function and expression of proteins for GABAergic signaling in the temporal cortex underlying larger E/I and worse cognitive performance. Further analysis of transcriptomic and in situ hybridization datasets from an independent cohort across the continuum of AD confirm regional differences in pro-excitatory shifts of the E/I balance that correlate negatively with the most recent calibrated composite scores for memory, executive function, language and visuospatial abilities, as well as overall cognitive performance. These findings indicate that early shifts of E/I balance may contribute to loss of cognitive capabilities in the continuum of AD clinical syndrome.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Humanos , Doença de Alzheimer/patologia , Disfunção Cognitiva/patologia , Encéfalo/patologia , Hipocampo/patologia , Cognição
12.
J Nutr ; 153(12): 3397-3405, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37898335

RESUMO

BACKGROUND: Regulation of mechanistic target of rapamycin complex 1 (mTORC1) plays an important role in aging and nutrition. For example, caloric restriction reduces mTORC1 signaling and extends lifespan, whereas nutrient abundance and obesity increase mTORC1 signaling and reduce lifespan. Skeletal muscle-specific knockout (KO) of DEP domain-containing 5 protein (DEPDC5) results in constitutively active mTORC1 signaling, muscle hypertrophy and an increase in mitochondrial respiratory capacity. The metabolic profile of skeletal muscle, in the setting of hyperactive mTORC1 signaling, is not well known. OBJECTIVES: To determine the metabolomic and lipidomic signature in skeletal muscle from female and male wild-type (WT) and DEPDC5 KO mice. METHODS: Tibialis anterior (TA) muscles from WT and transgenic (conditional skeletal muscle-specific DEPDC5 KO) were obtained from female and male adult mice. Polar metabolites and lipids were extracted using a Bligh-Dyer extraction from 5 samples per group and identified and quantified by LC-MS/MS. Resulting analyte peak areas were analyzed with t-test, analysis of variance, and Volcano plots for group comparisons (e.g., WT compared with KO) and multivariate statistical analysis for genotype and sex comparisons. RESULTS: A total of 162 polar metabolites (organic acids, amino acids, and amines and acyl carnitines) and 1141 lipid metabolites were detected in TA samples by LC-MS/MS. Few polar metabolites showed significant differences in KO muscles compared with WT within the same sex group. P-aminobenzoic acid, ß-alanine, and dopamine were significantly higher in KO male muscle whereas erythrose-4-phosphate and oxoglutaric acid were significantly reduced in KO females. The lipidomic profile of the KO groups revealed an increase of muscle phospholipids and reduced triacylglycerol and diacylglycerol compared with the WT groups. CONCLUSIONS: Sex differences were detected in polar metabolome and lipids were dependent on genotype. The metabolomic profile of mice with hyperactive skeletal muscle mTORC1 is consistent with an upregulation of mitochondrial function and amino acid utilization for protein synthesis.


Assuntos
Lipidômica , Espectrometria de Massas em Tandem , Feminino , Masculino , Camundongos , Animais , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Cromatografia Líquida , Músculo Esquelético/metabolismo , Camundongos Knockout , Lipídeos
13.
Proc Natl Acad Sci U S A ; 117(30): 17992-18001, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32669438

RESUMO

Dengue virus (DENV) was designated as a top 10 public health threat by the World Health Organization in 2019. No clinically approved anti-DENV drug is currently available. Here we report the high-resolution cocrystal structure (1.5 Å) of the DENV-2 capsid protein in complex with an inhibitor that potently suppresses DENV-2 but not other DENV serotypes. The inhibitor induces a "kissing" interaction between two capsid dimers. The inhibitor-bound capsid tetramers are assembled inside virions, resulting in defective uncoating of nucleocapsid when infecting new cells. Resistant DENV-2 emerges through one mutation that abolishes hydrogen bonds in the capsid structure, leading to a loss of compound binding. Structure-based analysis has defined the amino acids responsible for the inhibitor's inefficacy against other DENV serotypes. The results have uncovered an antiviral mechanism through inhibitor-induced tetramerization of the viral capsid and provided essential structural and functional knowledge for rational design of panserotype DENV capsid inhibitors.


Assuntos
Antivirais/química , Proteínas do Capsídeo/química , Vírus da Dengue , Modelos Moleculares , Conformação Proteica , Sequência de Aminoácidos , Antivirais/farmacologia , Sítios de Ligação , Proteínas do Capsídeo/genética , Vírus da Dengue/efeitos dos fármacos , Mutação , Nucleocapsídeo/química , Nucleocapsídeo/metabolismo , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Relação Estrutura-Atividade
14.
J Biol Chem ; 296: 100309, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33482196

RESUMO

Mitochondrial DNA is located in organelle that house essential metabolic reactions and contains high reactive oxygen species. Therefore, mitochondrial DNA suffers more oxidative damage than its nuclear counterpart. Formation of a repair enzyme complex is beneficial to DNA repair. Recent studies have shown that mitochondrial DNA polymerase (Pol γ) and poly(ADP-ribose) polymerase 1 (PARP1) were found in the same complex along with other mitochondrial DNA repair enzymes, and mitochondrial PARP1 level is correlated with mtDNA integrity. However, the molecular basis for the functional connection between Pol γ and PARP1 has not yet been elucidated because cellular functions of PARP1 in DNA repair are intertwined with metabolism via NAD+ (nicotinamide adenosine dinucleotide), the substrate of PARP1, and a metabolic cofactor. To dissect the direct effect of PARP1 on mtDNA from the secondary perturbation of metabolism, we report here biochemical studies that recapitulated Pol γ PARylation observed in cells and showed that PARP1 regulates Pol γ activity during DNA repair in a metabolic cofactor NAD+ (nicotinamide adenosine dinucleotide)-dependent manner. In the absence of NAD+, PARP1 completely inhibits Pol γ, while increasing NAD+ levels to a physiological concentration that enables Pol γ to resume maximum repair activity. Because cellular NAD+ levels are linked to metabolism and to ATP production via oxidative phosphorylation, our results suggest that mtDNA damage repair is coupled to cellular metabolic state and the integrity of the respiratory chain.


Assuntos
DNA Polimerase gama/genética , DNA Mitocondrial/genética , NAD/genética , Poli(ADP-Ribose) Polimerase-1/genética , Dano ao DNA/genética , Reparo do DNA/genética , Proteínas de Ligação a DNA/genética , Humanos , NAD/metabolismo , Estresse Oxidativo/genética , Poli ADP Ribosilação/genética , Conformação Proteica , Mapas de Interação de Proteínas/genética , Processamento de Proteína Pós-Traducional/genética , Espécies Reativas de Oxigênio/metabolismo
15.
N Engl J Med ; 381(7): 603-613, 2019 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-31180194

RESUMO

BACKGROUND: Type 1 diabetes is a chronic autoimmune disease that leads to destruction of insulin-producing beta cells and dependence on exogenous insulin for survival. Some interventions have delayed the loss of insulin production in patients with type 1 diabetes, but interventions that might affect clinical progression before diagnosis are needed. METHODS: We conducted a phase 2, randomized, placebo-controlled, double-blind trial of teplizumab (an Fc receptor-nonbinding anti-CD3 monoclonal antibody) involving relatives of patients with type 1 diabetes who did not have diabetes but were at high risk for development of clinical disease. Patients were randomly assigned to a single 14-day course of teplizumab or placebo, and follow-up for progression to clinical type 1 diabetes was performed with the use of oral glucose-tolerance tests at 6-month intervals. RESULTS: A total of 76 participants (55 [72%] of whom were ≤18 years of age) underwent randomization - 44 to the teplizumab group and 32 to the placebo group. The median time to the diagnosis of type 1 diabetes was 48.4 months in the teplizumab group and 24.4 months in the placebo group; the disease was diagnosed in 19 (43%) of the participants who received teplizumab and in 23 (72%) of those who received placebo. The hazard ratio for the diagnosis of type 1 diabetes (teplizumab vs. placebo) was 0.41 (95% confidence interval, 0.22 to 0.78; P = 0.006 by adjusted Cox proportional-hazards model). The annualized rates of diagnosis of diabetes were 14.9% per year in the teplizumab group and 35.9% per year in the placebo group. There were expected adverse events of rash and transient lymphopenia. KLRG1+TIGIT+CD8+ T cells were more common in the teplizumab group than in the placebo group. Among the participants who were HLA-DR3-negative, HLA-DR4-positive, or anti-zinc transporter 8 antibody-negative, fewer participants in the teplizumab group than in the placebo group had diabetes diagnosed. CONCLUSIONS: Teplizumab delayed progression to clinical type 1 diabetes in high-risk participants. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT01030861.).


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Complexo CD3/antagonistas & inibidores , Diabetes Mellitus Tipo 1/prevenção & controle , Adolescente , Adulto , Anticorpos Monoclonais Humanizados/efeitos adversos , Criança , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/imunologia , Progressão da Doença , Método Duplo-Cego , Exantema/induzido quimicamente , Feminino , Teste de Tolerância a Glucose , Antígeno HLA-DR3 , Antígeno HLA-DR4 , Humanos , Contagem de Linfócitos , Linfopenia/induzido quimicamente , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Linfócitos T/imunologia , Adulto Jovem
16.
Anal Chem ; 94(9): 3930-3938, 2022 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-35189062

RESUMO

Complete LC-MS-based protein primary sequence characterization requires measurement of intact protein profiles under denaturing and/or reducing conditions. To address issues of protein overcharging of unstructured proteins under acidic, denaturing conditions and sample heterogeneity (macro- and micro-scales) which often confound denaturing intact mass analysis of a wide variety of protein samples, we propose the use of broadband isolation of entire charge state distributions of intact proteins followed by ion-ion proton transfer charge reduction, which we have termed "full scan PTCR" (fsPTCR). Using rapid denaturing size exclusion chromatography coupled to fsPTCR-Orbitrap MS and time-resolved deconvolution data analysis, we demonstrate a strategy for method optimization, leading to significant analytical advantages over conventional MS1. Denaturing analysis of the flexible bacterial translation initiation factor 2 (91 kDa) using fsPTCR reduced overcharging and showed an 11-fold gain in S/N compared to conventional MS1. Analysis by fsPTCR-MS of the microheterogeneous glycoprotein fetuin revealed twice as many proteoforms as MS1 (112 vs 56). In a macroheterogeneous mixture of proteins ranging from 14 to 148 kDa, fsPTCR provided more than 10-fold increased sensitivity and quantitative accuracy for diluted bovine serum albumin (66 kDa). Finally, our analysis shows that collisional gas pressure is a key parameter which can be utilized during fsPTCR to retain or remove larger proteins from acquired spectra.


Assuntos
Prótons , Soroalbumina Bovina , Sequência de Aminoácidos , Cromatografia Líquida/métodos , Espectrometria de Massas , Soroalbumina Bovina/química
17.
Nucleic Acids Res ; 48(2): 817-829, 2020 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-31799610

RESUMO

Mitochondrial DNA (mtDNA) resides in a high ROS environment and suffers more mutations than its nuclear counterpart. Increasing evidence suggests that mtDNA mutations are not the results of direct oxidative damage, rather are caused, at least in part, by DNA replication errors. To understand how the mtDNA replicase, Pol γ, can give rise to elevated mutations, we studied the effect of oxidation of Pol γ on replication errors. Pol γ is a high fidelity polymerase with polymerase (pol) and proofreading exonuclease (exo) activities. We show that Pol γ exo domain is far more sensitive to oxidation than pol; under oxidative conditions, exonuclease activity therefore declines more rapidly than polymerase. The oxidized Pol γ becomes editing-deficient, displaying a 20-fold elevated mutations than the unoxidized enzyme. Mass spectrometry analysis reveals that Pol γ exo domain is a hotspot for oxidation. The oxidized exo residues increase the net negative charge around the active site that should reduce the affinity to mismatched primer/template DNA. Our results suggest that the oxidative stress induced high mutation frequency on mtDNA can be indirectly caused by oxidation of the mitochondrial replicase.


Assuntos
DNA Polimerase gama/genética , Replicação do DNA/genética , DNA Mitocondrial/genética , Estresse Oxidativo/genética , Domínio Catalítico/genética , DNA Polimerase gama/química , Reparo do DNA/genética , Exonucleases/genética , Mutação/genética , Conformação Proteica
18.
Fam Process ; 61(1): 58-75, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-33959959

RESUMO

Integrative systemic therapy (IST) is a meta-theoretical perspective, grounded in systemic theory and integration, that transcends therapy models in individual, couple, and family therapy. To foster supervisees' theoretical integration and systemic thinking, two of IST's primary tools-the essence diagram and blueprint-are described and applied to inform an integrative, systemic meta-perspective for supervision. Recommendations, specific guiding questions, and examples are provided to operationalize these tools in the multi-level supervision system (i.e., supervisor-supervisee-client system). IST supervisors and other supervisors who are interested in integrative, systemic training can use these tools to guide the process of supervision and strengthen supervisees' ability to hypothesize, plan, converse, and read clients' feedback in relation to the various tasks of therapy. The essence diagram and blueprint are applied to facilitate case consultation and cultivate the development of supervisees' clinical competencies. Particularly, the problem-solving focus of IST has been adapted to include a competency-based and professional growth-oriented dimension for supervision to better promote supervisees' development. Lastly, the advantages and challenges of IST-influenced supervision are discussed.


La terapia sistémica integral (TSI) es una perspectiva metateórica basada en la teoría sistémica y la integración, que trasciende los modelos de terapia en la terapia individual, de pareja y familiar. Para fomentar la integración teórica de los supervisados y el pensamiento sistémico, se describen y se aplican dos de las herramientas principales de la TSI-el diagrama del eje y el diseño- a fin de respaldar una metaperspectiva integradora y sistémica de la supervisión. Se ofrecen recomendaciones, preguntas orientadoras específicas y ejemplos para poner en funcionamiento estas herramientas en el sistema de supervisión multinivel (p. ej.: sistema supervisor-supervisado-paciente). Los supervisores de la TSI y otros supervisores que estén interesados en la capacitación integradora y sistémica pueden usar estas herramientas para guiar el proceso de supervisión y fortalecer la capacidad de los supervisados para plantear hipótesis, planificar, conversar y leer los comentarios de los pacientes en relación con las diferentes tareas de la terapia. El diagrama del eje y el diseño se aplican para facilitar la consulta de casos y cultivar el desarrollo de las competencias clínicas de los supervisados. Particularmente, se ha adaptado el eje de resolución de problemas de la TSI para incluir una dimensión basada en competencias y orientada al crecimiento profesional a fin de que la supervisión promueva mejor el desarrollo de los supervisados. Por último, se comentan las ventajas y las dificultades de la supervisión influida por la TSI.


Assuntos
Terapia Familiar , Terapia Familiar/métodos , Humanos
19.
Mil Psychol ; 34(3): 269-279, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-38536264

RESUMO

The measurement of self-reported suicide risk can be complicated in medical settings due to patient apprehension about the potential consequences of self-disclosure. The Suicide Cognitions Scale (SCS) was designed to assess suicide risk by measuring a range of suicidogenic cognitions (e.g., hopelessness, perceived burdensomeness) collectively referred to as the suicidal belief system. The SCS's concurrent, known groups, and prospective validity for suicidal thoughts and behaviors have previously been supported. The present study examined the factor structure, known-groups, and concurrent validity of a revised, 16-item version of the SCS (SCS-R), which removed two items that explicitly used the word "suicide" and changed item scoring from a 1-5 to 0-4 scale, thereby improving the interpretation of scores. In a sample of 2,690 primary care patients presenting for routine medical care at one of six US military clinics, results of bifactor analysis supported the scale's unidimensionality. The SCS-R significantly differentiated participants with a history of suicide attempts and was significantly correlated with frequency of thoughts about death and self-harm during the previous 2 weeks. Results align with earlier research and provide psychometric support for the SCS-R.

20.
Ann Fam Med ; 19(6): 492-498, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34750123

RESUMO

PURPOSE: Over 95% of patients who screen positive on the Patient Health Questionnaire-9 (PHQ-9) suicide risk item do not attempt or die by suicide, which could lead to unnecessary treatment and/or misallocation of limited resources. The present study seeks to determine if suicide risk screening can be meaningfully improved to identify the highest-risk patients. METHODS: Patients eligible to receive medical treatment from the US Department of Defense medical system were recruited from 6 military primary care clinics located at 5 military installations around the United States. Patients completed self-report measures including the PHQ-9 and 16 items from the Suicide Cognitions Scale (SCS) during routine primary care clinic visits. Postbaseline suicidal behaviors (suicide attempts, interrupted attempts, and aborted attempts) were assessed by evaluators who were blind to screening results using the Self-Injurious Thoughts and Behaviors Interview. RESULTS: Among 2,744 patients, 13 (0.5%) engaged in suicidal behavior in the 30 days after screening and 28 (1.0%) displayed suicidal behavior in the 90 days after screening. Multiple SCS items differentiated patients with suicidal behavior less than 30 days after screening positive for suicide risk. Augmenting the PHQ-9 suicide risk item with SCS items improved the identification of patients who were most likely to have suicidal behavior within a month of screening positive without sacrificing sensitivity. CONCLUSION: Among primary care patients who screen positive for suicide risk on the PHQ-9, SCS items improved screening efficiency by identifying those patients who are most likely to engage in suicidal behavior within the next 30 days.


Assuntos
Ideação Suicida , Tentativa de Suicídio , Humanos , Programas de Rastreamento , Atenção Primária à Saúde , Inquéritos e Questionários , Estados Unidos
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