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1.
Am J Hum Biol ; : e24075, 2024 Mar 21.
Article in English | MEDLINE | ID: mdl-38515310

ABSTRACT

BACKGROUND: Changes of maternal triglyceride concentrations are closely associated with intrauterine fetal growth and development, but the effect of mid- to late-term triglyceride changes on birth weight is uncertain. This study investigated the association between changes in triglycerides in mid to late in pregnant women gestational age ≥ 35 weeks on neonatal birth weight and adverse outcomes. METHODS: This cohort study was based on 931 pregnant women with a singleton delivery at gestational age ≥ 35 weeks from January 1, 2022 to December 31, 2022 at Nanjing Lishui People's Hospital (NJLSPH) in China, with all maternal triglyceride concentrations measured at mid-term and late-term before delivery. The primary outcomes were neonatal birth weight and the risk of macrosomia. RESULTS: Late term triglyceride levels were positively associated with birth weight (ß = 126.40, 95% CI: 61.95, 190.84, p < .001) and risk of macrosomia (OR = 2.11, 95% CI: 1.12, 3.98, p = .022). Late mid-term triglyceride was positively associated with birth weight (ß = 27.58, 95% CI: 9.67, 45.50, p = .003), and no correlation with risk of macrosomia (OR = 1.12, 95% CI: 0.95, 1.31, p = .178). Mid-term triglyceride was not associated with birth weight (ß = 45.79, 95% CI: -28.73, 120.30, p = .229) and risk of macrosomia (OR = 1.83, 95% CI: 0.89, 3.78, p = .101). CONCLUSION: Late triglyceride levels were associated with birth weight and risk of macrosomia, while late to mid-term triglyceride were associated with birth weight but not with risk of macrosomia. This suggests that maternal triglyceride changes may affect fetal growth and development, and more studies focusing on the effects of gestational triglyceride profiles are warranted.

2.
J Am Chem Soc ; 145(18): 10015-10021, 2023 05 10.
Article in English | MEDLINE | ID: mdl-37104712

ABSTRACT

Caspases are a family of cysteine-dependent proteases with important cellular functions in inflammation and apoptosis, while also implicated in human diseases. Classical chemical tools to study caspase functions lack selectivity for specific caspase family members due to highly conserved active sites and catalytic machinery. To overcome this limitation, we targeted a non-catalytic cysteine residue (C264) unique to caspase-6 (C6), an enigmatic and understudied caspase isoform. Starting from disulfide ligands identified in a cysteine trapping screen, we used a structure-informed covalent ligand design to produce potent, irreversible inhibitors (3a) and chemoproteomic probes (13-t) of C6 that exhibit unprecedented selectivity over other caspase family members and high proteome selectivity. This approach and the new tools described will enable rigorous interrogation of the role of caspase-6 in developmental biology and in inflammatory and neurodegenerative diseases.


Subject(s)
Caspases , Cysteine , Humans , Caspase 6 , Apoptosis , Cysteine Proteinase Inhibitors/pharmacology
3.
Nature ; 550(7677): 534-538, 2017 10 26.
Article in English | MEDLINE | ID: mdl-29045385

ABSTRACT

The ubiquitin system regulates essential cellular processes in eukaryotes. Ubiquitin is ligated to substrate proteins as monomers or chains and the topology of ubiquitin modifications regulates substrate interactions with specific proteins. Thus ubiquitination directs a variety of substrate fates including proteasomal degradation. Deubiquitinase enzymes cleave ubiquitin from substrates and are implicated in disease; for example, ubiquitin-specific protease-7 (USP7) regulates stability of the p53 tumour suppressor and other proteins critical for tumour cell survival. However, developing selective deubiquitinase inhibitors has been challenging and no co-crystal structures have been solved with small-molecule inhibitors. Here, using nuclear magnetic resonance-based screening and structure-based design, we describe the development of selective USP7 inhibitors GNE-6640 and GNE-6776. These compounds induce tumour cell death and enhance cytotoxicity with chemotherapeutic agents and targeted compounds, including PIM kinase inhibitors. Structural studies reveal that GNE-6640 and GNE-6776 non-covalently target USP7 12 Å distant from the catalytic cysteine. The compounds attenuate ubiquitin binding and thus inhibit USP7 deubiquitinase activity. GNE-6640 and GNE-6776 interact with acidic residues that mediate hydrogen-bond interactions with the ubiquitin Lys48 side chain, suggesting that USP7 preferentially interacts with and cleaves ubiquitin moieties that have free Lys48 side chains. We investigated this idea by engineering di-ubiquitin chains containing differential proximal and distal isotopic labels and measuring USP7 binding by nuclear magnetic resonance. This preferential binding protracted the depolymerization kinetics of Lys48-linked ubiquitin chains relative to Lys63-linked chains. In summary, engineering compounds that inhibit USP7 activity by attenuating ubiquitin binding suggests opportunities for developing other deubiquitinase inhibitors and may be a strategy more broadly applicable to inhibiting proteins that require ubiquitin binding for full functional activity.


Subject(s)
Aminopyridines/chemistry , Aminopyridines/pharmacology , Indazoles/chemistry , Indazoles/pharmacology , Phenols/chemistry , Phenols/pharmacology , Pyridines/chemistry , Pyridines/pharmacology , Ubiquitin-Specific Peptidase 7/antagonists & inhibitors , Ubiquitin/metabolism , Animals , Binding, Competitive , Cell Line, Tumor , Drug Synergism , Female , Humans , Mice , Mice, SCID , Models, Molecular , Neoplasms/drug therapy , Neoplasms/enzymology , Neoplasms/pathology , Protein Binding , Proto-Oncogene Proteins c-mdm2/metabolism , Proto-Oncogene Proteins c-pim-1/antagonists & inhibitors , Substrate Specificity , Tumor Suppressor Protein p53/deficiency , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Ubiquitin/chemistry , Ubiquitin-Specific Peptidase 7/chemistry , Ubiquitin-Specific Peptidase 7/deficiency , Ubiquitin-Specific Peptidase 7/metabolism
4.
Biochemistry ; 61(21): 2295-2302, 2022 11 01.
Article in English | MEDLINE | ID: mdl-36264309

ABSTRACT

Autophagy is a catabolic cellular process in which unwanted proteins and organelles are degraded by lysosomes. It is characterized by the formation of the double-membrane autophagosome decorated with LC3B, a protein that mediates autophagosomal fusion with lysosomes. The cysteine protease ATG4b acts at two stages in the life cycle of LC3B. We set out to characterize the protein-protein interaction between LC3B and ATG4b. Through biochemical and biophysical studies, we show that the ubiquitin-like core of LC3B (residues 1-115; "LC3B-115"), which lacks the C-terminal cleavage site (between residue 120 and 121), binds to full-length ATG4b with a surprisingly tight dissociation constant (KD) in the low nanomolar range; 10-30-fold tighter than that of the substrate pro-LC3B (residues 1-125) or the product LC3B-I (residues 1-120). Consequently, LC3B-115 is a potent inhibitor of the ATG4b-mediated cleavage of pro-LC3B (IC50 = 15 nM). Binding of the LC3B-115 has no effect on the conformation of the active site of ATG4b, as judged by the turnover of a peptide substrate ("substrate-33"), derived from LC3B-I residues 116-120. Conversely, truncations of ATG4b show that binding and proteolysis of LC3B critically depend on the C-terminal tail of ATG4b, whereas proteolysis of the peptide substrate-33 does not require the C-terminal tail of ATG4b. These results support a bipartite model for LC3B-ATG4b binding in which the core of LC3B binds to ATG4b and the C-terminal tail of pro-LC3B organizes the ATG4b active site; additionally, the C-terminal tail of ATG4b contributes at least 1000-fold higher binding affinity to the LC3B-ATG4b interaction and likely wraps around the LC3B-ubiquitin core. PPIs are often described as containing an energetic "hot spot" for binding; in the case of LC3B-ATG4b, however, the substrate-enzyme complex contains multiple, energetically relevant domains that differentially affect binding affinity and catalytic efficiency.


Subject(s)
Cysteine Endopeptidases , Peptide Hydrolases , Autophagy-Related Proteins , Cysteine Endopeptidases/metabolism , Autophagy , Autophagy-Related Protein 8 Family , Peptides/pharmacology , Microtubule-Associated Proteins/metabolism
5.
Biotechnol Appl Biochem ; 69(1): 160-165, 2022 Feb.
Article in English | MEDLINE | ID: mdl-33369762

ABSTRACT

Acute myocardial infarction (AMI) is the heart attack happening when the blood flow is terminated to the heart muscles. C-reactive protein (CRP) level is raising significantly in AMI patients after the onset of symptom; also, temporal variations of CRP in plasma of AMI patient have also been found. Quantifying the concentration of CRP helps to identify the condition associated with AMI. Plasmonic enzyme-linked immunosorbent assay (ELISA) was utilized here to identify CRP by the sandwich of aptamer and antibody. Bare-eye CRP detection was achieved by plasmonic ELISA through the aggregation (blue color) of gold nanoparticle in the presence of CRP, whereas in the absence of CRP, it retains its red color (dispersion). Depending on the catalase presence on the ELISA surface, hydrogen peroxide (H2 O2 ) controls gold growth and differentiates with color changes. To achieve the lowest detection limit of CRP, H2 O2 (200 µM), gold seed (0.2 µM), and streptavidin-catalase (1:500) were found optimal. The detection limit was reached at 0.25 µg/mL, whereas it was 0.5 µg/mL in the CRP-spiked serum. This method of detection system is easier to detect the levels of CRP and helps diagnosing AMI.


Subject(s)
Heart Diseases , Metal Nanoparticles , Biomarkers , Enzyme-Linked Immunosorbent Assay , Gold , Humans
6.
Clin Endocrinol (Oxf) ; 87(5): 581-586, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28543314

ABSTRACT

OBJECTIVE: Subclinical hypothyroidism (SCH) has been associated with atherosclerosis and increased risk of ischaemic stroke. However, whether SCH is associated with cerebral small vessel disease (cSVD) remains largely unexplored. This study aimed to investigate the relationship between SCH and total cSVD burden, a composite measurement detected with magnetic resonance imaging (MRI), in patients with minor ischaemic stroke or transient ischaemic attack (TIA). DESIGN: This was a prospective observational cohort study conducted in a tertiary referral hospital. METHODS: Subclinical hypothyroidism (SCH) was defined as with mildly or moderately increased thyroid-stimulating hormone levels (TSH, 4.5-10.0 mIU/L), but with normal free thyroxine levels. Brain MRI presence of silent lacunar infarcts (LIs), white matter lesions (WMLs), cerebral microbleeds (CMBs) and enlarged perivascular spaces (EPVs) were summed to a validated scales ranging from 0 to 4 to represent the load of cSVD. The associations between SCH and cSVD were analysed by logistic regression analyses. RESULTS: Subclinical hypothyroidism (SCH) was identified in 43 of 229 (18.8%) patients with minor stroke or TIA. Compared with patients without SCH, those with SCH had higher risks of WMLs, CMBs and total cSVD burden. Adjustment of potential confounders did not change these associations. CONCLUSIONS: These findings showed that SCH might be associated with the presence of WMLs, CMBs, as well as cSVD burden in patients with minor stroke or TIA.


Subject(s)
Cerebral Small Vessel Diseases/diagnostic imaging , Hypothyroidism/complications , Aged , Cerebral Small Vessel Diseases/complications , Female , Humans , Ischemic Attack, Transient/complications , Magnetic Resonance Imaging , Male , Middle Aged , Prospective Studies , Risk , Stroke/complications
7.
Zhongguo Dang Dai Er Ke Za Zhi ; 15(3): 179-82, 2013 Mar.
Article in Zh | MEDLINE | ID: mdl-23498757

ABSTRACT

OBJECTIVE: To investigate the clinical features of Mycoplasma pneumoniae pneumonia (MPP) among children of different ages. METHODS: Retrospective analysis was performed on the clinical data of 112 children who were hospitalized due to MMP between January 2010 and December 2011. The children were divided into 3 groups according to their ages: infants (<3 years; n=20), preschool-aged children (≥3 years; n=41), and school-aged children (6-15.2 years; n=51). The three groups were compared in terms of their clinical symptoms, pulmonary signs, chest X-ray findings and laboratory test results. RESULTS: The infant group presented mainly with expectoration and wheezing, accompanied by low fever. They showed gastrointestinal symptoms as the most common extra-pulmonary manifestation and had evident pulmonary signs. The majority of the school-aged children group presented with high fever and a severe dry cough, and wheezing was seen in several of them. They showed rash as the most common extra-pulmonary manifestation and had slight pulmonary signs. The symptoms of the preschool-aged children group were in between. In the infant and preschool-aged children groups, most showed bronchopneumonia on chest X-ray, while in the school-aged children group, chest X-rays mostly showed segmental parenchymatous infiltration. The infant group had a higher lymphocyte count than the school-aged children group, while the school-aged children group had a higher serum C-reactive protein level than the infant group. CONCLUSIONS: The clinical features of MPP are different among children of different ages, especially between infants and school-aged children.


Subject(s)
Pneumonia, Mycoplasma/diagnosis , Adolescent , Age Factors , Antibodies, Bacterial/blood , Child , Child, Preschool , Female , Humans , Infant , Male , Pneumonia, Mycoplasma/diagnostic imaging , Pneumonia, Mycoplasma/drug therapy , Radiography, Thoracic , Retrospective Studies
8.
Sci Rep ; 13(1): 13668, 2023 08 22.
Article in English | MEDLINE | ID: mdl-37608223

ABSTRACT

Coronaviruses have been the causative agent of three epidemics and pandemics in the past two decades, including the ongoing COVID-19 pandemic. A broadly-neutralizing coronavirus therapeutic is desirable not only to prevent and treat COVID-19, but also to provide protection for high-risk populations against future emergent coronaviruses. As all coronaviruses use spike proteins on the viral surface to enter the host cells, and these spike proteins share sequence and structural homology, we set out to discover cross-reactive biologic agents targeting the spike protein to block viral entry. Through llama immunization campaigns, we have identified single domain antibodies (VHHs) that are cross-reactive against multiple emergent coronaviruses (SARS-CoV, SARS-CoV-2, and MERS). Importantly, a number of these antibodies show sub-nanomolar potency towards all SARS-like viruses including emergent CoV-2 variants. We identified nine distinct epitopes on the spike protein targeted by these VHHs. Further, by engineering VHHs targeting distinct, conserved epitopes into multi-valent formats, we significantly enhanced their neutralization potencies compared to the corresponding VHH cocktails. We believe this approach is ideally suited to address both emerging SARS-CoV-2 variants during the current pandemic as well as potential future pandemics caused by SARS-like coronaviruses.


Subject(s)
COVID-19 , Camelids, New World , Single-Domain Antibodies , Humans , Animals , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Pandemics , Epitopes
9.
J Biol Chem ; 286(39): 34147-54, 2011 Sep 30.
Article in English | MEDLINE | ID: mdl-21828056

ABSTRACT

Caspase-2, the most evolutionarily conserved member in the human caspase family, may play important roles in stress-induced apoptosis, cell cycle regulation, and tumor suppression. In biochemical assays, caspase-2 uniquely prefers a pentapeptide (such as VDVAD) rather than a tetrapeptide, as required for efficient cleavage by other caspases. We investigated the molecular basis for pentapeptide specificity using peptide analog inhibitors and substrates that vary at the P5 position. We determined the crystal structures of apo caspase-2, caspase-2 in complex with peptide inhibitors VDVAD-CHO, ADVAD-CHO, and DVAD-CHO, and a T380A mutant of caspase-2 in complex with VDVAD-CHO. Two residues, Thr-380 and Tyr-420, are identified to be critical for the P5 residue recognition; mutation of the two residues reduces the catalytic efficiency by about 4- and 40-fold, respectively. The structures also provide a series of snapshots of caspase-2 in different catalytic states, shedding light on the mechanism of capase-2 activation, substrate binding, and catalysis. By comparing the apo and inhibited caspase-2 structures, we propose that the disruption of a non-conserved salt bridge between Glu-217 and the invariant Arg-378 is important for the activation of caspase-2. These findings broaden our understanding of caspase-2 substrate specificity and catalysis.


Subject(s)
Caspase 2/chemistry , Cysteine Endopeptidases/chemistry , Amino Acid Substitution , Apoenzymes/chemistry , Apoenzymes/genetics , Apoenzymes/metabolism , Caspase 2/genetics , Caspase 2/metabolism , Catalysis , Crystallography, X-Ray , Cysteine Endopeptidases/genetics , Cysteine Endopeptidases/metabolism , Cysteine Proteinase Inhibitors/chemistry , Humans , Mutation, Missense , Oligopeptides/chemistry , Protein Structure, Tertiary , Structure-Activity Relationship , Substrate Specificity
10.
Acta Cir Bras ; 36(2): e360207, 2021.
Article in English | MEDLINE | ID: mdl-33656046

ABSTRACT

PURPOSE: The present study explored the influence of liraglutide on remote preconditioning-mediated cardioprotection in diabetes mellitus along with the role of nuclear factor erythroid 2-related factor 2 (Nrf2), hypoxia inducible factor (HIF-1α) and hydrogen sulfide (H2S). METHODS: Streptozotocin was given to rats to induce diabetes mellitus and rats were kept for eight weeks. Four cycles of ischemia and reperfusion were given to hind limb to induce remote preconditioning. After 24 h, hearts were isolated and subjected to 30 min of ischemia and 120 min of reperfusion on Langendorff system. Liraglutide was administered along with remote preconditioning. Cardiac injury was assessed by measuring the release of creatine kinase (CK-MB), cardiac troponin (cTnT) and development of left ventricular developed pressure. After ischemia-reperfusion, hearts were homogenized to measure the nuclear cytoplasmic ratio of Nrf2, H2S and HIF-1α levels. RESULTS: In diabetic rats, there was more pronounced injury and the cardioprotective effects of remote preconditioning were not observed. Administration of liraglutide restored the cardioprotective effects of remote preconditioning in a dose-dependent manner. Moreover, liraglutide increased the Nrf2, H2S and HIF-1α levels in remote preconditioning-subjected diabetic rats. CONCLUSIONS: Liraglutide restores the lost cardioprotective effects of remote preconditioning in diabetes by increasing the expression of Nrf2, H2S and HIF-1α.


Subject(s)
Diabetes Mellitus, Experimental , Hydrogen Sulfide , Ischemic Preconditioning, Myocardial , Ischemic Preconditioning , Myocardial Infarction , Myocardial Reperfusion Injury , Animals , Diabetes Mellitus, Experimental/drug therapy , Hydrogen Sulfide/pharmacology , Liraglutide/pharmacology , Myocardial Reperfusion Injury/prevention & control , NF-E2-Related Factor 2 , Rats , Rats, Wistar , Signal Transduction
11.
J Immunother Cancer ; 9(5)2021 05.
Article in English | MEDLINE | ID: mdl-34001523

ABSTRACT

BACKGROUND: NKTR-255 is a novel polyethylene glycol-conjugate of recombinant human interleukin-15 (rhIL-15), which was designed to retain all known receptor binding interactions of the IL-15 molecule. We explored the biologic and pharmacologic differences between endogenous IL-15 receptor α (IL-15Rα)-dependent (NKTR-255 and rhIL-15) and IL-15Rα-independent (precomplexed rhIL-15/IL-15Rα) cytokines. METHODS: In vitro pharmacological properties of rhIL-15, NKTR-255 and precomplex cytokines (rhIL-15/IL-15Rα and rhIL-15 N72D/IL-15Rα Fc) were investigated in receptor binding, signaling and cell function. In vivo pharmacokinetic (PK) and pharmacodynamic profile of the cytokines were evaluated in normal mice. Finally, immunomodulatory effect and antitumor activity were assessed in a Daudi lymphoma model. RESULTS: NKTR-255 and rhIL-15 exhibited similar in vitro properties in receptor affinity, signaling and leukocyte degranulation, which collectively differed from precomplexed cytokines. Notably, NKTR-255 and rhIL-15 stimulated greater granzyme B secretion in human peripheral blood mononuclear cells versus precomplexed cytokines. In vivo, NKTR-255 exhibited a PK profile with reduced clearance and a longer half-life relative to rhIL-15 and demonstrated prolonged IL-15R engagement in lymphocytes compared with only transient engagement observed for rhIL-15 and precomplexed rhIL-15 N72D/IL-15Rα Fc. As a consequent, NKTR-255 provided a durable and sustained proliferation and activation of natural killer (NK) and CD8+ T cells. Importantly, NKTR-255 is more effective than the precomplexed cytokine at inducing functionally competent, cytotoxic NK cells in the tumor microenvironment and the properties of NKTR-255 translated into superior antitumor activity in a B-cell lymphoma model versus the precomplexed cytokine. CONCLUSIONS: Our results show that the novel immunotherapeutic, NKTR-255, retains the full spectrum of IL-15 biology, but with improved PK properties, over rhIL-15. These findings support the ongoing phase 1 first-in-human trial (NCT04136756) of NKTR-255 in participants with relapsed or refractory hematologic malignancies, potentially advancing rhIL-15-based immunotherapies for the treatment of cancer.


Subject(s)
Antineoplastic Agents/therapeutic use , Burkitt Lymphoma/drug therapy , Interleukin-15/therapeutic use , Lymphocytes/drug effects , Polyethylene Glycols/therapeutic use , Receptors, Interleukin-15/agonists , Animals , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/pharmacology , Burkitt Lymphoma/pathology , Cell Degranulation/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Cytokines/metabolism , Female , HEK293 Cells , Humans , Interleukin-15/pharmacokinetics , Interleukin-15/pharmacology , Lymphocyte Activation/drug effects , Lymphocytes/immunology , Lymphocytes/metabolism , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Knockout , Mice, SCID , Polyethylene Glycols/pharmacokinetics , Polyethylene Glycols/pharmacology , Receptors, Interleukin-15/genetics , Receptors, Interleukin-15/metabolism , Signal Transduction , Tumor Microenvironment
12.
J Transl Autoimmun ; 4: 100103, 2021.
Article in English | MEDLINE | ID: mdl-34041473

ABSTRACT

Impaired interleukin-2 (IL-2) production and regulatory T-cell dysfunction have been implicated as immunological mechanisms central to the pathogenesis of multiple autoimmune and inflammatory diseases. NKTR-358, a novel regulatory T-cell stimulator, is an investigational therapeutic that selectively restores regulatory T-cell homeostasis in these diseases. We investigated NKTR-358's selectivity for regulatory T-cells, receptor-binding properties, ex vivo and in vivo pharmacodynamics, ability to suppress conventional T-cell proliferation in mice and non-human primates, and functional activity in a murine model of systemic lupus erythematosus. In vitro, NKTR-358 demonstrated decreased affinity for IL-2Rα, IL-2Rß, and IL-2Rαß compared with recombinant human IL-2 (rhIL-2). A single dose of NKTR-358 in cynomolgus monkeys produced a greater than 15-fold increase in regulatory T-cells, and the increase lasted until day 14, while daily rhIL-2 administration for 5 days only elicited a 3-fold increase, which lasted until day 7. Repeated dosing of NKTR-358 over 6 months in cynomolgus monkeys elicited cyclical, robust increases in regulatory T-cells with no loss in drug activity over the course of treatment. Regulatory T-cells isolated from NKTR-358-treated mice displayed a sustained, higher suppression of conventional T-cell proliferation than regulatory T-cells isolated from vehicle-treated mice. NKTR-358 treatment in a mouse model (MRL/MpJ-Faslpr) of systemic lupus erythematosus for 12 weeks maintained elevated regulatory T-cells for the treatment duration and ameliorated disease progression. Together, these results suggest that NKTR-358 has the ability to elicit sustained and preferential proliferation and activation of regulatory T-cells without corresponding effects on conventional T-cells, with improved pharmacokinetics compared with rhIL-2.

13.
Mol Neurodegener ; 15(1): 2, 2020 01 06.
Article in English | MEDLINE | ID: mdl-31906970

ABSTRACT

BACKGROUND: The trans-neuronal propagation of tau has been implicated in the progression of tau-mediated neurodegeneration. There is critical knowledge gap in understanding how tau is released and transmitted, and how that is dysregulated in diseases. Previously, we reported that lysine acetyltransferase p300/CBP acetylates tau and regulates its degradation and toxicity. However, whether p300/CBP is involved in regulation of tau secretion and propagation is unknown. METHOD: We investigated the relationship between p300/CBP activity, the autophagy-lysosomal pathway (ALP) and tau secretion in mouse models of tauopathy and in cultured rodent and human neurons. Through a high-through-put compound screen, we identified a new p300 inhibitor that promotes autophagic flux and reduces tau secretion. Using fibril-induced tau spreading models in vitro and in vivo, we examined how p300/CBP regulates tau propagation. RESULTS: Increased p300/CBP activity was associated with aberrant accumulation of ALP markers in a tau transgenic mouse model. p300/CBP hyperactivation blocked autophagic flux and increased tau secretion in neurons. Conversely, inhibiting p300/CBP promoted autophagic flux, reduced tau secretion, and reduced tau propagation in fibril-induced tau spreading models in vitro and in vivo. CONCLUSIONS: We report that p300/CBP, a lysine acetyltransferase aberrantly activated in tauopathies, causes impairment in ALP, leading to excess tau secretion. This effect, together with increased intracellular tau accumulation, contributes to enhanced spreading of tau. Our findings suggest that inhibition of p300/CBP as a novel approach to correct ALP dysfunction and block disease progression in tauopathy.


Subject(s)
Neurons/metabolism , Tauopathies/metabolism , p300-CBP Transcription Factors/metabolism , tau Proteins/metabolism , Animals , Autophagy/physiology , Humans , Lysosomes/metabolism , Mice , Mice, Transgenic , Rats, Sprague-Dawley
14.
Chem Biol ; 14(8): 931-43, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17719492

ABSTRACT

We report the 2.6 A X-ray crystal structure of a 190 kDa homodimeric fragment from module 3 of the 6-deoxyerthronolide B synthase covalently bound to the inhibitor cerulenin. The structure shows two well-organized interdomain linker regions in addition to the full-length ketosynthase (KS) and acyltransferase (AT) domains. Analysis of the substrate-binding site of the KS domain suggests that a loop region at the homodimer interface influences KS substrate specificity. We also describe a model for the interaction of the catalytic domains with the acyl carrier protein (ACP) domain. The ACP is proposed to dock within a deep cleft between the KS and AT domains, with interactions that span both the KS homodimer and AT domain. In conjunction with other recent data, our results provide atomic resolution pictures of several catalytically relevant protein interactions in this remarkable family of modular megasynthases.


Subject(s)
Polyketide Synthases/metabolism , Base Sequence , Binding Sites , Catalytic Domain , Cerulenin/metabolism , Circular Dichroism , Crystallography, X-Ray , DNA Primers , Dimerization , Models, Molecular , Mutagenesis, Site-Directed , Polyketide Synthases/chemistry , Protein Conformation
15.
Bioorg Med Chem Lett ; 18(10): 3034-8, 2008 May 15.
Article in English | MEDLINE | ID: mdl-18243693

ABSTRACT

The critical role of protein-protein interactions in the chemistry of polyketide synthases is well established. However, the transient and weak nature of these interactions, in particular those involving the acyl carrier protein (ACP), has hindered efforts to structurally characterize these interactions. We describe a chemo-enzymatic approach that crosslinks the active sites of ACP and their cognate ketosynthase (KS) domains, resulting in the formation of a stable covalent adduct. This process is driven by specific protein-protein interactions between KS and ACP domains. Suitable manipulation of the reaction conditions enabled complete crosslinking of a representative KS and ACP, allowing isolation of a stable, conformationally constrained adduct suitable for high-resolution structural analysis.


Subject(s)
Acyl Carrier Protein/chemistry , Cross-Linking Reagents/chemistry , Polyketide Synthases/chemistry , Protein Engineering , Blotting, Western , Electrophoresis, Polyacrylamide Gel , Molecular Structure , Protein Binding , Protein Structure, Tertiary
16.
Chem Biol ; 13(6): 637-47, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16793521

ABSTRACT

We describe the heterologous expression in Escherichia coli of the proenzyme precursor to EP-B2, a cysteine endoprotease from germinating barley seeds. High yields (50 mg/l) of recombinant proEP-B2 were obtained from E. coli inclusion bodies in shake flask cultures following purification and refolding. The zymogen was rapidly autoactivated to its mature form under acidic conditions at a rate independent of proEP-B2 concentration, suggesting a cis mechanism of autoactivation. Mature EP-B2 was stable and active over a wide pH range and efficiently hydrolyzed a recombinant wheat gluten protein, alpha2-gliadin, at sequences with known immunotoxicity in celiac sprue patients. The X-ray crystal structure of mature EP-B2 bound to leupeptin was solved to 2.2 A resolution and provided atomic insights into the observed subsite specificity of the endoprotease. Our findings suggest that orally administered proEP-B2 may be especially well suited for treatment of celiac sprue.


Subject(s)
Cysteine Endopeptidases/chemistry , Cysteine Endopeptidases/metabolism , Hordeum/enzymology , Protein Folding , Amino Acid Sequence , Crystallography, X-Ray , Cysteine Endopeptidases/genetics , Cysteine Endopeptidases/isolation & purification , Enzyme Activation , Escherichia coli , Gene Expression , Glutens/metabolism , Hordeum/genetics , Hydrogen-Ion Concentration , Kinetics , Leupeptins/chemistry , Leupeptins/metabolism , Molecular Sequence Data , Pepsin A/metabolism , Protein Precursors/chemistry , Protein Precursors/genetics , Protein Precursors/isolation & purification , Protein Precursors/metabolism , Protein Structure, Quaternary , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Structure-Activity Relationship , Substrate Specificity , Trypsin/metabolism
17.
Acta cir. bras ; 36(2): e360207, 2021. tab, graf
Article in English | LILACS | ID: biblio-1152700

ABSTRACT

ABSTRACT Purpose The present study explored the influence of liraglutide on remote preconditioning-mediated cardioprotection in diabetes mellitus along with the role of nuclear factor erythroid 2-related factor 2 (Nrf2), hypoxia inducible factor (HIF-1α) and hydrogen sulfide (H2S). Methods Streptozotocin was given to rats to induce diabetes mellitus and rats were kept for eight weeks. Four cycles of ischemia and reperfusion were given to hind limb to induce remote preconditioning. After 24 h, hearts were isolated and subjected to 30 min of ischemia and 120 min of reperfusion on Langendorff system. Liraglutide was administered along with remote preconditioning. Cardiac injury was assessed by measuring the release of creatine kinase (CK-MB), cardiac troponin (cTnT) and development of left ventricular developed pressure. After ischemia-reperfusion, hearts were homogenized to measure the nuclear cytoplasmic ratio of Nrf2, H2S and HIF-1α levels. Results In diabetic rats, there was more pronounced injury and the cardioprotective effects of remote preconditioning were not observed. Administration of liraglutide restored the cardioprotective effects of remote preconditioning in a dose-dependent manner. Moreover, liraglutide increased the Nrf2, H2S and HIF-1α levels in remote preconditioning-subjected diabetic rats. Conclusions Liraglutide restores the lost cardioprotective effects of remote preconditioning in diabetes by increasing the expression of Nrf2, H2S and HIF-1α.


Subject(s)
Animals , Rats , Myocardial Reperfusion Injury/prevention & control , Ischemic Preconditioning, Myocardial , Diabetes Mellitus, Experimental/drug therapy , Hydrogen Sulfide , Hydrogen Sulfide/pharmacology , Myocardial Infarction , Signal Transduction , Rats, Wistar , NF-E2-Related Factor 2 , Liraglutide/pharmacology
18.
Oxid Med Cell Longev ; 2016: 8346301, 2016.
Article in English | MEDLINE | ID: mdl-27119010

ABSTRACT

BACKGROUND AND AIMS: Metabolic syndrome (MetS) has been associated with occurrence and prognosis of ischemic stroke. This study aimed to evaluate whether an association exists between MetS and early neurological deterioration (END) following acute ischemic stroke and the possible role inflammatory biomarkers play. METHODS AND RESULTS: . We conducted a prospective cohort investigation that involved 208 stroke patients within 48 hours from symptom onset. MetS was determined by the modified National Cholesterol Education Program/Adult Treatment Panel III criteria. END was defined as an increase of ⩾1 point in motor power or ⩾2 points in the total National Institutes of Health Stroke Scale (NIHSS) score within 7 days. Univariate logistic regression analysis showed that patients with MetS had a 125% increased risk of END (OR 2.25; 95% CI 1.71-4.86, P = 0.005). After adjustment for fibrinogen and high-sensitivity C-reactive protein, MetS remained significantly correlated to END (OR 2.20; 95% CI 1.10-4.04, P = 0.026) with a 77% elevated risk per additional MetS trait (OR 1.77; 95% CI 1.23-2.58, P = 0.002). CONCLUSIONS: . This study demonstrated that MetS may be a potential predictor for END after ischemic stroke, which was independent of raised inflammatory mediators.


Subject(s)
Brain Ischemia/complications , Hospitals , Inflammation Mediators/metabolism , Metabolic Syndrome/complications , Neurons/pathology , Stroke/complications , Adult , Aged , Aged, 80 and over , Female , Humans , Logistic Models , Male , Middle Aged , Odds Ratio , Prospective Studies , Risk Factors
19.
ACS Med Chem Lett ; 7(1): 77-82, 2016 Jan 14.
Article in English | MEDLINE | ID: mdl-26819670

ABSTRACT

A series of oxyguanidine analogues of the cysteine protease inhibitor WRR-483 were synthesized and evaluated against cruzain, the major cysteine protease of the protozoan parasite Trypanosoma cruzi. Kinetic analyses of these analogues indicated that they have comparable potency to previously prepared vinyl sulfone cruzain inhibitors. Co-crystal structures of the oxyguanidine analogues WRR-666 (4) and WRR-669 (7) bound to cruzain demonstrated different binding interactions with the cysteine protease, depending on the aryl moiety of the P1' inhibitor subunit. Specifically, these data demonstrate that WRR-669 is bound noncovalently in the crystal structure. This represents a rare example of noncovalent inhibition of a cysteine protease by a vinyl sulfone inhibitor.

20.
Chem Biol ; 21(9): 1102-14, 2014 Sep 18.
Article in English | MEDLINE | ID: mdl-25237857

ABSTRACT

The past 20 years have seen many advances in our understanding of protein-protein interactions (PPIs) and how to target them with small-molecule therapeutics. In 2004, we reviewed some early successes; since then, potent inhibitors have been developed for diverse protein complexes, and compounds are now in clinical trials for six targets. Surprisingly, many of these PPI clinical candidates have efficiency metrics typical of "lead-like" or "drug-like" molecules and are orally available. Successful discovery efforts have integrated multiple disciplines and make use of all the modern tools of target-based discovery-structure, computation, screening, and biomarkers. PPIs become progressively more challenging as the interfaces become more complex, i.e., as binding epitopes are displayed on primary, secondary, or tertiary structures. Here, we review the last 10 years of progress, focusing on the properties of PPI inhibitors that have advanced to clinical trials and prospects for the future of PPI drug discovery.


Subject(s)
Proteins/antagonists & inhibitors , Small Molecule Libraries/chemistry , Allosteric Regulation/drug effects , Apoptosis Regulatory Proteins/antagonists & inhibitors , Apoptosis Regulatory Proteins/metabolism , Binding Sites , HIV Integrase/chemistry , HIV Integrase/metabolism , Humans , Peptides/chemistry , Peptides/metabolism , Protein Interaction Domains and Motifs/drug effects , Protein Interaction Maps/drug effects , Protein Structure, Secondary , Protein Structure, Tertiary , Proteins/metabolism , Small Molecule Libraries/metabolism , Small Molecule Libraries/pharmacology
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