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1.
Proc Natl Acad Sci U S A ; 119(11): e2121609119, 2022 03 15.
Article in English | MEDLINE | ID: mdl-35259016

ABSTRACT

SignificanceNeurodegenerative diseases are poorly understood and difficult to treat. One common hallmark is lysosomal dysfunction leading to the accumulation of aggregates and other undegradable materials, which cause damage to brain resident cells. Lysosomes are acidic organelles responsible for breaking down biomolecules and recycling their constitutive parts. In this work, we find that the antiinflammatory and neuroprotective compound, discovered via a phenotypic screen, imparts its beneficial effects by targeting the lysosome and restoring its function. This is established using a genome-wide CRISPRi target identification screen and then confirmed using a variety of lysosome-targeted studies. The resulting small molecule from this study represents a potential treatment for neurodegenerative diseases as well as a research tool for the study of lysosomes in disease.


Subject(s)
Anti-Inflammatory Agents/pharmacology , Lysosomes/drug effects , Neurodegenerative Diseases/metabolism , Animals , Anti-Inflammatory Agents/chemistry , Biomarkers , Brain/drug effects , Brain/metabolism , Disease Models, Animal , Disease Susceptibility , Drug Development , Gene Expression Profiling , Humans , Mice , Neurodegenerative Diseases/drug therapy , Neurodegenerative Diseases/etiology , Neurodegenerative Diseases/pathology , Neurons/drug effects , Neurons/metabolism , Smad Proteins/agonists
2.
Chem Soc Rev ; 53(8): 3640-3655, 2024 Apr 22.
Article in English | MEDLINE | ID: mdl-38450536

ABSTRACT

Hydrogen-bonded porous frameworks (HPFs) are versatile porous crystalline frameworks with diverse applications. However, designing chiral assemblies or biocompatible materials poses significant challenges. Peptide-based hydrogen-bonded porous frameworks (P-HPFs) are an exciting alternative to conventional HPFs due to their intrinsic chirality, tunability, biocompatibility, and structural diversity. Flexible, ultra-short peptide-based P-HPFs (composed of 3 or fewer amino acids) exhibit adaptable porous topologies that can accommodate a variety of guest molecules and capture hazardous greenhouse gases. Longer, folded peptides present challenges and opportunities in designing P-HPFs. This review highlights recent developments in P-HPFs using ultra-short peptides, folded peptides, and foldamers, showcasing their utility for gas storage, chiral recognition, chiral separation, and medical applications. It also addresses design challenges and future directions in the field.


Subject(s)
Hydrogen Bonding , Peptides , Peptides/chemistry , Porosity
3.
J Am Chem Soc ; 146(32): 22236-22246, 2024 Aug 14.
Article in English | MEDLINE | ID: mdl-39096501

ABSTRACT

Peptide-based frameworks aim to integrate protein architecture into solid-state materials using simpler building blocks. Despite the growing number of peptide frameworks, there are few strategies to rationally engineer essential properties like pore size and shape. Designing peptide assemblies is generally hindered by the difficulty of predicting complex networks of weak intermolecular interactions. Peptides conjugated to polyaromatic groups are a unique case where assembly appears to be strongly driven by π-π interactions, suggesting that rationally adjusting the geometry of the π-stackers could create novel structures. Here, we report peptide elongation as a simple mechanism to predictably tune the angle between the π-stacking groups to produce a remarkable diversity of pore shapes and sizes, including some that are mesoporous. Notably, rapid jumps in pore size and shape can occur with just a single amino acid insertion. The geometry of the π-stacking residues also significantly influences framework structure, representing an additional dimension for tuning. Lastly, sequence identity can also indirectly modulate the π-π interactions. By correlating each of these factors with detailed crystallographic data, we find that, despite the complexity of peptide structure, the shape and polarity of the tectons are straightforward predictors of framework structure. These guidelines are expected to accelerate the development of advanced porous materials with protein-like capabilities.


Subject(s)
Peptides , Peptides/chemistry , Porosity , Models, Molecular , Peptidomimetics/chemistry , Peptidomimetics/chemical synthesis
4.
Chemistry ; : e202402101, 2024 Aug 16.
Article in English | MEDLINE | ID: mdl-39152095

ABSTRACT

Metal binding to ß-sheets occurs in many metalloproteins and is also implicated in the pathology of Alzheimer's disease. De novo designed metallo-ß-sheets have been pursued as models and mimics of these proteins. However, no crystal structures of canonical ß-sheet metallopeptides have yet been obtained, in stark contrast to many examples for ɑ-helical metallopeptides, leading to a poor understanding for their chemistry. To address this, we have engineered tryptophan zippers, stable 12-residue ß-sheet peptides, to bind Cu(II) ions and obtained crystal structures through single crystal X-ray diffraction (SC-XRD). We find that metal binding triggers several unexpected supramolecular assemblies that demonstrate the range of higher-order structures available to metallo-ß-sheets. Overall, these findings underscore the importance of crystallography in elucidating the rich structural landscape of metallo-ß-sheet peptides.

5.
Biomacromolecules ; 25(3): 2016-2023, 2024 Mar 11.
Article in English | MEDLINE | ID: mdl-38362872

ABSTRACT

Porous framework materials are highly useful for catalysis, adsorption, and separations. Though they are usually made from inorganic and organic building blocks, recently, folded peptides have been utilized for constructing frameworks, opening up an enormous structure-space for exploration. These peptides assemble in a metal-free fashion using π-stacking, H-bonding, dispersion forces, and the hydrophobic effect. Manipulation of pore-defining H-bonding residues is known to generate new topologies, but the impact of mutations in the hydrophobic packing region facing away from the pores is less obvious. To explore their effects, we synthesized variants of peptide frameworks with mutations in the hydrophobic packing positions and found by single-crystal X-ray crystallography (SC-XRD) that they induce significant changes to the framework pore structure. These structural changes are driven by a need to maximize van der Waals interactions of the nonpolar groups, which are achieved by various mechanisms including helix twisting, chain flipping, chain offsetting, and desymmetrization. Even subtle changes to the van der Waals interface, such as the introduction of a methyl group or isomeric replacement, result in significant pore restructuring. This study shows that the dispersion interactions upholding a peptide material are a rich area for structural engineering.


Subject(s)
Metals , Peptides , Metals/chemistry , Crystallography, X-Ray , Peptides/genetics , Mutation
6.
J Am Chem Soc ; 145(36): 19588-19600, 2023 Sep 13.
Article in English | MEDLINE | ID: mdl-37639365

ABSTRACT

Though thiols are exceptionally versatile, their high reactivity has also hindered the synthesis and characterization of well-defined thiol-containing porous materials. Leveraging the mild conditions of the noncovalent peptide assembly, we readily synthesized and characterized a number of frameworks with thiols displayed at many unique positions and in several permutations. Importantly, nearly all assemblies were structurally determined using single-crystal X-ray diffraction to reveal their rich sequence-structure landscape and the cooperative noncovalent interactions underlying their assembly. These observations and supporting molecular dynamics calculations enabled rational engineering by the positive and negative design of noncovalent interactions. Furthermore, the thiol-containing frameworks undergo diverse single-crystal-to-single-crystal reactions, including toxic metal ion coordination (e.g., Cd2+, Pb2+, and Hg2+), selective uptake of Hg2+ ions, and redox transformations. Notably, we find a framework that supports thiol-nitrosothiol interconversion, which is applicable for biocompatible nitric oxide delivery. The modularity, ease of synthesis, functionality, and well-defined nature of these peptide-based thiol frameworks are expected to accelerate the design of complex materials with reactive active sites.

7.
PLoS Biol ; 18(9): e3000866, 2020 09.
Article in English | MEDLINE | ID: mdl-32881857

ABSTRACT

The small GTPase RhoA is a central signaling enzyme that is involved in various cellular processes such as cytoskeletal dynamics, transcription, and cell cycle progression. Many signal transduction pathways activate RhoA-for instance, Gαq-coupled Histamine 1 Receptor signaling via Gαq-dependent activation of RhoGEFs such as p63. Although multiple upstream regulators of RhoA have been identified, the temporal regulation of RhoA and the coordination of different upstream components in its regulation have not been well characterized. In this study, live-cell measurement of RhoA activation revealed a biphasic increase of RhoA activity upon histamine stimulation. We showed that the first and second phase of RhoA activity are dependent on p63 and Ca2+/PKC, respectively, and further identified phosphorylation of serine 240 on p115 RhoGEF by PKC to be the mechanistic link between PKC and RhoA. Combined approaches of computational modeling and quantitative measurement revealed that the second phase of RhoA activation is insensitive to rapid turning off of the receptor and is required for maintaining RhoA-mediated transcription after the termination of the receptor signaling. Thus, two divergent pathways enable both rapid activation and persistent signaling in receptor-mediated RhoA signaling via intricate temporal regulation.


Subject(s)
Histamine/pharmacology , rhoA GTP-Binding Protein/metabolism , Animals , Calcium Signaling/drug effects , Cells, Cultured , Enzyme Activation/drug effects , HeLa Cells , Humans , Mice , Phosphorylation/drug effects , Protein Kinase C/metabolism , Receptors, Histamine/metabolism , Rho Guanine Nucleotide Exchange Factors/metabolism , Signal Transduction/drug effects
8.
Int J Behav Nutr Phys Act ; 20(1): 66, 2023 06 03.
Article in English | MEDLINE | ID: mdl-37268953

ABSTRACT

BACKGROUND: Fruit and vegetable (FV) consumption in children in the United States (US) is very low. Adequate FV consumption is required for proper development during childhood, and dietary habits are established during preschool-age and tend to persist into adulthood. As most U.S. preschool-aged children attend childcare or preschool, this may be an opportune time and setting to conduct interventions to improve FV intake. These interventions should be based in theory and use behavior change techniques (BCTs) to explain mechanisms for expected change. To date, no published reviews have examined the effectiveness of childcare- or preschool-based FV interventions in preschoolers and their use of theoretical frameworks and BCTs. METHODS: This systematic review was completed adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria were randomized controlled trials (RCTs) published between 2012 and 2022 of interventions to improve diet or FV intake in preschoolers (aged 2-5 years) in childcare or preschool-settings. A search of four databases was conducted between in September 2022 using search terms pertaining to the study's primary aim (FV consumption), age group (preschool-aged), settings (US childcare or preschool settings), and study design (RCT). Additional criteria were objective measures of FV consumption or skin carotenoids, as a proxy for FV intake. Included studies were narratively synthesized based on intervention type, measured effect, and use of theory and BCTs. RESULTS: The search resulted in six studies that reported on nine interventions. Overall, six interventions increased FV intake, of which five used nutrition education and one manipulated the feeding environment. Among the three interventions with no measured effect, two manipulated the feeding environment and one used peer modeling. Effective studies used at least three BCTs, though no pattern was observed between use of theory or BCTs and intervention effect. CONCLUSIONS: While several studies have shown promising results, the limited number of studies identified in this review highlights key gaps in this field: there is a need for studies to test FV interventions in US childcare settings that use objective measures of FV intake, directly compare intervention components and BCTs, are theory-based, and assess long-term behavior change.


Subject(s)
Fruit , Vegetables , Child, Preschool , Humans , Child , Child Care , Eating , Behavior Therapy/methods
9.
Proc Natl Acad Sci U S A ; 117(12): 6339-6348, 2020 03 24.
Article in English | MEDLINE | ID: mdl-32165539

ABSTRACT

DNA nanotechnology has established approaches for designing programmable and precisely controlled nanoscale architectures through specific Watson-Crick base-pairing, molecular plasticity, and intermolecular connectivity. In particular, superior control over DNA origami structures could be beneficial for biomedical applications, including biosensing, in vivo imaging, and drug and gene delivery. However, protecting DNA origami structures in complex biological fluids while preserving their structural characteristics remains a major challenge for enabling these applications. Here, we developed a class of structurally well-defined peptoids to protect DNA origamis in ionic and bioactive conditions and systematically explored the effects of peptoid architecture and sequence dependency on DNA origami stability. The applicability of this approach for drug delivery, bioimaging, and cell targeting was also demonstrated. A series of peptoids (PE1-9) with two types of architectures, termed as "brush" and "block," were built from positively charged monomers and neutral oligo-ethyleneoxy monomers, where certain designs were found to greatly enhance the stability of DNA origami. Through experimental and molecular dynamics studies, we demonstrated the role of sequence-dependent electrostatic interactions of peptoids with the DNA backbone. We showed that octahedral DNA origamis coated with peptoid (PE2) can be used as carriers for anticancer drug and protein, where the peptoid modulated the rate of drug release and prolonged protein stability against proteolytic hydrolysis. Finally, we synthesized two alkyne-modified peptoids (PE8 and PE9), conjugated with fluorophore and antibody, to make stable DNA origamis with imaging and cell-targeting capabilities. Our results demonstrate an approach toward functional and physiologically stable DNA origami for biomedical applications.


Subject(s)
DNA/chemistry , Nanostructures/chemistry , Peptoids/chemistry , Drug Delivery Systems , Molecular Dynamics Simulation , Molecular Structure , Nanostructures/administration & dosage , Nanotechnology , Peptoids/chemical synthesis , Static Electricity
10.
Educ Inf Technol (Dordr) ; 28(4): 4221-4241, 2023.
Article in English | MEDLINE | ID: mdl-36254344

ABSTRACT

The advancement of artificial intelligence in education (AIED) has the potential to transform the educational landscape and influence the role of all involved stakeholders. In recent years, the applications of AIED have been gradually adopted to progress our understanding of students' learning and enhance learning performance and experience. However, the adoption of AIED has led to increasing ethical risks and concerns regarding several aspects such as personal data and learner autonomy. Despite the recent announcement of guidelines for ethical and trustworthy AIED, the debate revolves around the key principles underpinning ethical AIED. This paper aims to explore whether there is a global consensus on ethical AIED by mapping and analyzing international organizations' current policies and guidelines. In this paper, we first introduce the opportunities offered by AI in education and potential ethical issues. Then, thematic analysis was conducted to conceptualize and establish a set of ethical principles by examining and synthesizing relevant ethical policies and guidelines for AIED. We discuss each principle and associated implications for relevant educational stakeholders, including students, teachers, technology developers, policymakers, and institutional decision-makers. The proposed set of ethical principles is expected to serve as a framework to inform and guide educational stakeholders in the development and deployment of ethical and trustworthy AIED as well as catalyze future development of related impact studies in the field.

11.
Educ Inf Technol (Dordr) ; 28(5): 5999-6026, 2023.
Article in English | MEDLINE | ID: mdl-36373047

ABSTRACT

Recently, the coronavirus disease 2019 (COVID-19) pandemic has led to rapid digitalisation in education, requiring educators to adopt several technologies simultaneously for online learning and teaching. Using a large-scale survey (N = 1740), this study aims to construct a model that predicts teachers' extensive technology acceptance by extending the Technology Acceptance Model (TAM) with their technological pedagogical content knowledge (TPACK) and innovativeness. TAM has been a valuable tool to measure the adoption of new technology in various contexts, including education. However, TAM has been designed and principally applied to assess user acceptance of a specific technology implementation. This study has extended TAM to measure teachers' technology-enabled practice (online teaching) with the adoption of various technologies. The proposed model explains teachers' behavioural intention to teach online with a good fit. Our findings revealed the collective effects of TPACK, perceived usefulness (PU) of technology, and innovativeness on teachers' behavioural intention to teach online post-pandemic. Moreover, the study identified training and support from school as a significant predictor for both teachers' TPACK and PU. The novelty of this study lies in its model conceptualisation that incorporates both information-technology-based constructs and personal-competence-based features, including TPACK and innovativeness. Furthermore, our study contributes to the growing body of literature that addresses the online teaching adoption by schoolteachers in the post-pandemic era.

12.
J Am Chem Soc ; 144(4): 1475-1492, 2022 02 02.
Article in English | MEDLINE | ID: mdl-35060704

ABSTRACT

Cobalt oxides are recognized as one of the most efficient earth-abundant catalysts for challenging oxidation chemistry, with substrates ranging from water to organic compounds. In these oxidations, cobalt-oxo species with formal oxidation states greater than 3 are commonly invoked as reactive intermediates. However, there is a dearth of mechanistic information regarding how these high-valent cobalt catalysts operate. This Perspective describes how the study of molecular cobalt oxo clusters, with an emphasis on [Co4O4] oxo cubane complexes, has helped to shed light on the operative mechanisms of cobalt-catalyzed oxidation reactions. Implications for high-valent CoIV-oxo and CoV-oxo intermediates and remaining mechanistic questions concerning how these intermediates mediate O-O bond formation are also discussed. Furthermore, structural modifications of these oxo cubane clusters (i.e., incorporation of heteroatoms and modulation of ligands) have provided insight into multimetallic cooperativity, but the influence of such metal-metal interactions on oxidation activity remains to be explored. A more detailed understanding of these structure-activity relationships may enable fine-tuning of reactivity and stability of synthetic multimetallic catalysts for energy storage and challenging organic transformations.

13.
J Am Chem Soc ; 144(15): 7001-7009, 2022 04 20.
Article in English | MEDLINE | ID: mdl-35390261

ABSTRACT

The evolution of proteins from simpler, self-assembled peptides provides a powerful blueprint for the design of complex synthetic materials. Previously, peptide-metal frameworks using short sequences (≤3 residues) have shown great promise as proteomimetic materials that exhibit sophisticated capabilities. However, their development has been hindered due to few variable residues and restricted choice of side-chains that are compatible with metal ions. Herein, we developed a noncovalent strategy featuring π-stacking bipyridyl residues to assemble much longer peptides into crystalline frameworks that tolerate even previously incompatible acidic and basic functionalities and allow an unprecedented level of pore variations. Single-crystal X-ray structures are provided for all variants to guide and validate rational design. These materials exhibit hallmark proteomimetic behaviors such as guest-selective induced fit and assembly of multimetallic units. Significantly, we demonstrate facile optimization of the framework design to substantially increase affinity toward a complex organic molecule.


Subject(s)
Metals , Peptides , 2,2'-Dipyridyl , Metals/chemistry , Porosity , Proteins/chemistry
14.
Am J Physiol Endocrinol Metab ; 322(6): E508-E516, 2022 06 01.
Article in English | MEDLINE | ID: mdl-35373585

ABSTRACT

Increased adiposity is associated with dysregulation of the endothelin system, both of which increase the risk of cardiovascular disease (CVD). Preclinical data indicate that endothelin dysregulation also reduces resting energy expenditure (REE). The objective was to test the hypothesis that endothelin receptor antagonism will increase REE in people with obesity compared with healthy weight individuals. Using a double blind, placebo-controlled, crossover design, 32 participants [healthy weight (HW): n = 16, BMI: 21.3 ± 2.8 kg/m2, age: 26 ± 7 yr and overweight/obese (OB): n = 16, BMI: 33.5 ± 9.5 kg/m2, age: 31 ± 6 yr] were randomized to receive either 125 mg of bosentan (ETA/B antagonism) or placebo twice per day for 3 days. Breath-by-breath gas exchange data were collected and REE was assessed by indirect calorimetry. Venous blood samples were analyzed for concentrations of endothelin-1 (ET-1). Treatment with bosentan increased plasma ET-1 in both OB and HW groups. Within the OB group, the changes in absolute REE (PLA: -77.6 ± 127.6 vs. BOS: 72.2 ± 146.6 kcal/day; P = 0.046). The change in REE was not different following either treatment in the HW group. Overall, absolute plasma concentrations of ET-1 following treatment with bosentan were significantly associated with kcal/day of fat (r = 0.488, P = 0.005), percentage of fat utilization (r = 0.415, P = 0.020), and inversely associated with the percentage of carbohydrates (r = -0.419, P = 0.019), and respiratory exchange ratio (r = -0.407, P = 0.023). Taken together, these results suggest that modulation of the endothelin system may represent a novel therapeutic approach to increase both resting metabolism and caloric expenditure, and reduce CVD risk in people with increased adiposity.NEW & NOTEWORTHY Findings from our current translational investigation demonstrate that dual endothelin A/B receptor antagonism increases total REE in overweight/obese individuals. These results suggest that modulation of the endothelin system may represent a novel therapeutic target to increase both resting metabolism and caloric expenditure, enhance weight loss, and reduce CVD risk in seemingly healthy individuals with elevated adiposity.


Subject(s)
Adiposity , Cardiovascular Diseases , Adult , Basal Metabolism , Bosentan , Calorimetry, Indirect , Endothelins/metabolism , Energy Metabolism , Humans , Obesity/metabolism , Overweight/metabolism , Receptors, Endothelin/metabolism , Young Adult
15.
Inorg Chem ; 61(17): 6679-6687, 2022 May 02.
Article in English | MEDLINE | ID: mdl-35446044

ABSTRACT

Metalloenzymes have benefited from the iterative process of evolution to achieve the precise arrangements of secondary sphere non-covalent interactions that enhance metal-centered catalysis. Iterative synthesis of scaffolds that display complex secondary sphere elements in abiotic systems can be highly challenging and time-intensive. To overcome this synthetic bottleneck, we developed a highly modular and rapid synthetic strategy, leveraging the efficiency of solid-phase peptide synthesis and conformational control afforded by non-canonical residues to construct a ligand platform displaying up to four unique residues of varying electronics and sterics in the secondary coordination sphere. As a proof-of-concept that peptidic secondary sphere can cooperate with the metal complex, we applied this scaffold to a well-known, modestly active C-H oxidizing Fe catalyst to evolve specific non-covalent interactions that is more than double its catalytic activity. Solution-state NMR structures of several catalyst variants suggest that higher activity is correlated with a hydrophobic pocket above the Fe center that may enhance the formation of a catalyst-substrate complex. Above all, we show that peptides are a convenient, highly modular, and structurally defined ligand platform for creating secondary coordination spheres that comprise multiple, diverse functional groups.


Subject(s)
Coordination Complexes , Metalloproteins , Catalysis , Coordination Complexes/chemistry , Ligands , Metalloproteins/chemistry , Peptides
16.
BMC Nephrol ; 23(1): 362, 2022 11 11.
Article in English | MEDLINE | ID: mdl-36368937

ABSTRACT

INTRODUCTION: Extended-release calcifediol (ERC), active vitamin D hormones and analogs (AVD) and nutritional vitamin D (NVD) are commonly used therapies for treating secondary hyperparathyroidism (SHPT) in adults with stage 3-4 chronic kidney disease (CKD) and vitamin D insufficiency (VDI). Their effectiveness for increasing serum total 25-hydroxyvitamin D (25D) and reducing elevated plasma parathyroid hormone (PTH), the latter of which is associated with increased morbidity and mortality, has varied across controlled clinical trials. This study aimed to assess real-world experience of ERC and other vitamin D therapies in reducing PTH and increasing 25D. METHODS: Medical records of 376 adult patients with stage 3-4 CKD and a history of SHPT and VDI from 15 United States (US) nephrology clinics were reviewed for up to 1 year pre- and post-ERC, NVD or AVD initiation. Key study variables included patient demographics, concomitant usage of medications and laboratory data. The mean age of the study population was 69.5 years, with gender and racial distributions representative of the US CKD population. Enrolled patients were grouped by treatment into three cohorts: ERC (n = 174), AVD (n = 55) and NVD (n = 147), and mean baseline levels were similar for serum 25D (18.8-23.5 ng/mL), calcium (Ca: 9.1-9.3 mg/dL), phosphorus (P: 3.7-3.8 mg/dL) and estimated glomerular filtration rate (eGFR: 30.3-35.7 mL/min/1.73m2). Mean baseline PTH was 181.4 pg/mL for the ERC cohort versus 156.9 for the AVD cohort and 134.8 pg/mL (p < 0.001) for the NVD cohort. Mean follow-up during treatment ranged from 20.0 to 28.8 weeks. RESULTS: Serum 25D rose in all cohorts (p < 0.001) during treatment. ERC yielded the highest increase (p < 0.001) of 23.7 ± 1.6 ng/mL versus 9.7 ± 1.5 and 5.5 ± 1.3 ng/mL for NVD and AVD, respectively. PTH declined with ERC treatment by 34.1 ± 6.6 pg/mL (p < 0.001) but remained unchanged in the other two cohorts. Serum Ca increased 0.2 ± 0.1 pg/mL (p < 0.001) with AVD but remained otherwise stable. Serum alkaline phosphatase remained unchanged. CONCLUSIONS: Real-world clinical effectiveness and safety varied across the therapies under investigation, but only ERC effectively raised mean 25D (to well above 30 ng/mL) and reduced mean PTH levels without causing hypercalcemia.


Subject(s)
Hyperparathyroidism, Secondary , Renal Insufficiency, Chronic , Adult , Humans , Aged , Calcifediol/therapeutic use , Vitamin D , Hyperparathyroidism, Secondary/drug therapy , Hyperparathyroidism, Secondary/etiology , Vitamins/therapeutic use , Parathyroid Hormone , Renal Insufficiency, Chronic/drug therapy , Renal Insufficiency, Chronic/epidemiology , Calcium
17.
Proc Natl Acad Sci U S A ; 116(24): 11630-11639, 2019 06 11.
Article in English | MEDLINE | ID: mdl-31142656

ABSTRACT

A major challenge to the implementation of artificial photosynthesis (AP), in which fuels are produced from abundant materials (water and carbon dioxide) in an electrochemical cell through the action of sunlight, is the discovery of active, inexpensive, safe, and stable catalysts for the oxygen evolution reaction (OER). Multimetallic molecular catalysts, inspired by the natural photosynthetic enzyme, can provide important guidance for catalyst design, but the necessary mechanistic understanding has been elusive. In particular, fundamental transformations for reactive intermediates are difficult to observe, and well-defined molecular models of such species are highly prone to decomposition by intermolecular aggregation. Here, we present a general strategy for stabilization of the molecular cobalt-oxo cubane core (Co4O4) by immobilizing it as part of metal-organic frameworks, thus preventing intermolecular pathways of catalyst decomposition. These materials retain the OER activity and mechanism of the molecular Co4O4 analog yet demonstrate unprecedented long-term stability at pH 14. The organic linkers of the framework allow for chemical fine-tuning of activity and stability and, perhaps most importantly, provide "matrix isolation" that allows for observation and stabilization of intermediates in the water-splitting pathway.

18.
Am J Nephrol ; 52(10-11): 798-807, 2021.
Article in English | MEDLINE | ID: mdl-34818216

ABSTRACT

INTRODUCTION: The safety and efficacy of extended-release calcifediol (ERC) as a treatment for secondary hyperparathyroidism (SHPT) in adults with stage 3 or 4 chronic kidney disease (CKD) and vitamin D insufficiency (VDI) has been demonstrated in prospective randomized clinical trials (RCTs). ERC (Rayaldee®) was approved by the Food and Drug Administration in 2016 on the basis of these prospective RCTs. The current retrospective study assessed the postlaunch data available with respect to ERC's efficacy and safety in increasing serum 25-hydroxyvitamin D (25D) and reducing parathyroid hormone (PTH) in the indicated population. MATERIALS AND METHODS: Medical records of 174 patients who met study criteria from 15 geographically representative United States nephrology clinics were reviewed for 1 year before and after initiation of ERC treatment. Enrolled subjects had ages ≥18 years, stage 3 or 4 CKD, and a history of SHPT and VDI. Key study variables included patient demographics, medication usage, and laboratory results, including serial 25D and PTH determinations. RESULTS: The enrolled subjects had a mean age of 69.0 years, gender and racial distributions representative of the indicated population, and were balanced for CKD stage. Most (98%) received 30 mcg of ERC/day during the course of treatment (mean follow-up: 24 weeks). Baseline 25D and PTH levels averaged 20.3 ± 0.7 (standard error) ng/mL and 181 ± 7.4 pg/mL, respectively. ERC treatment raised 25D by 23.7 ± 1.6 ng/mL (p < 0.001) and decreased PTH by 34.1 ± 6.6 pg/mL (p < 0.001) with nominal changes of 0.1 mg/dL (p > 0.05) in serum calcium (Ca) and phosphorus (P) levels. DISCUSSION/CONCLUSION: Analysis of postlaunch data confirmed ERC's effectiveness in increasing serum 25D and reducing PTH levels without statistically significant or notable impact on serum Ca and P levels. A significant percentage of these subjects achieved 25D levels ≥30 mg/mL and PTH levels which decreased by at least 30% from baseline. Dose titration to 60 mcgs was rarely prescribed. Closer patient monitoring and appropriate dose titration may have led to a higher percentage of subjects achieving an increase in 25D levels to at least 50 ng/mL and a reduction in PTH levels of at least 30%.


Subject(s)
Calcifediol/therapeutic use , Hyperparathyroidism, Secondary/drug therapy , Vitamins/therapeutic use , Aged , Aged, 80 and over , Calcifediol/adverse effects , Delayed-Action Preparations , Female , Humans , Male , Middle Aged , Retrospective Studies , Treatment Outcome , Vitamins/adverse effects
19.
Brain Behav Immun ; 94: 274-288, 2021 05.
Article in English | MEDLINE | ID: mdl-33540074

ABSTRACT

Traumatic brain injury (TBI) is a leading cause of long-term neurological disability. Currently there is no effective pharmacological treatment for patients suffering from the long-lasting symptoms of TBI. We recently discovered that colony stimulating factor 1 (CSF1), an essential regulator of macrophage homeostasis, is neuroprotective and reduces neuroinflammation in two models of neurological disease in mice. Here we used a mouse model of repetitive mild TBI (mTBI) to examine whether CSF1 would attenuate cognitive deficits and improve pathological outcomes in two paradigms. In the acute paradigm, a single bolus treatment of CSF1 administered 24 h after injury significantly reduces memory impairment and astrocyte reactivity assessed 3 months later. In the chronic paradigm, the mice were tested 3 months after mTBI when they showed cognitive deficits. The mice were then randomly assigned to receive CSF1 or PBS (as control) treatment. After one month of treatment, the PBS-treated mice remained cognitively impaired, but the CSF1-treated showed significant improvements in cognitive function. RNA-seq and Ingenuity Pathway Analysis reveals CSF1 treatment alters cognition- and memory-related transcriptomic changes and pathways. The results of this study show that acute as well as delayed CSF1 treatment attenuate chronically impaired cognitive functions and improve pathological outcomes long after mTBI. The wide therapeutic time window of CSF1, together with the fact that CSF1 is approved for human use in clinical trials, strongly supports the potential clinical usefulness of this treatment in patients with mTBI.


Subject(s)
Brain Concussion , Brain Injuries, Traumatic , Cognition Disorders , Cognitive Dysfunction , Animals , Brain Concussion/complications , Brain Concussion/drug therapy , Brain Injuries, Traumatic/complications , Brain Injuries, Traumatic/drug therapy , Cognitive Dysfunction/drug therapy , Disease Models, Animal , Humans , Macrophage Colony-Stimulating Factor , Mice
20.
Plant Dis ; 105(9): 2418-2425, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34494871

ABSTRACT

The European grapevine (Vitis vinifera L.) has been cultivated in North America for about 500 years. One of the major limitations to its culture is the powdery mildew (PM) fungus, Erysiphe necator Schw. This study reports on the most extensive screening of Vitis species from the southwestern United States and northern Mexico for resistance to PM, testing 147 accessions of 13 Vitis species. In addition, Vitis vinifera cv. Carignane, a highly susceptible wine grape cultivar, was used as a reference to evaluate the effect of the inoculum 14 days postinoculation. Inoculation was done with a vacuum-operated settling tower using a broadly virulent isolate of E. necator, the C-strain. Resistant accessions (nine), moderately susceptible accessions (39), and highly susceptible accessions (99) were detected. The resistant accessions were then inoculated with an additional fungal isolate, e1-101, and they retained their resistance. Vitis species susceptibility was not associated with a North-South gradation, but Western species were more susceptible than Midwestern and Eastern species. All five of the V. monticola accessions were susceptible, as were the accessions of V. treleasei. The species V. acerifolia, V. candicans, V. cinerea, and V. × doaniana had significantly more resistant to moderately susceptible accessions compared with V. arizonica, V. berlandieri, V. californica, V. × champinii, V. girdiana, V. riparia, and V. rupestris, which had relatively more susceptible accessions than the other species. This research identified new sources of PM resistance in Vitis from the southwestern United States that could be incorporated into PM resistance breeding programs throughout the world.


Subject(s)
Ascomycota , Vitis , Disease Resistance , Plant Diseases , Southwestern United States
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