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1.
Chem Sci ; 15(4): 1364-1373, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38274066

RESUMO

Copper-catalysed radical-relay reactions that employ N-fluorobenzenesulfonimide (NFSI) as the oxidant have emerged as highly effective methods for C(sp3)-H functionalization. Herein, computational studies are paired with experimental data to investigate a series of key mechanistic features of these reactions, with a focus on issues related to site-selectivity, enantioselectivity, and C-H substrate scope. (1) The full reaction energetics of enantioselective benzylic C-H cyanation are probed, and an adduct between Cu and the N-sulfonimidyl radical (˙NSI) is implicated as the species that promotes hydrogen-atom transfer (HAT) from the C-H substrate. (2) Benzylic versus 3° C-H site-selectivity is compared with different HAT reagents: Cu/˙NSI, ˙OtBu, and Cl˙, and the data provide insights into the high selectivity for benzylic C-H bonds in Cu/NFSI-catalyzed C-H functionalization reactions. (3) The energetics of three radical functionalization pathways are compared, including radical-polar crossover (RPC) to generate a carbocation intermediate, reductive elimination from a formal CuIII organometallic complex, and radical addition to a Cu-bound ligand. The preferred mechanism is shown to depend on the ligands bound to copper. (4) Finally, the energetics of three different pathways that convert benzylic C-H bonds into benzylic cations are compared, including HAT/ET (ET = electron transfer), relevant to the RPC mechanism with Cu/NFSI; hydride transfer, involved in reactions with high-potential quinones; and sequential ET/PT/ET (PT = proton transfer), involved in catalytic photoredox reactions. Collectively, the results provide mechanistic insights that establish a foundation for further advances in radical-relay C-H functionalization reactions.

2.
Nat Chem ; 16(2): 285-293, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37884667

RESUMO

Modular functionalization enables versatile exploration of chemical space and has been broadly applied in structure-activity relationship (SAR) studies of aromatic scaffolds during drug discovery. Recently, the bicyclo[1.1.1]pentane (BCP) motif has increasingly received attention as a bioisosteric replacement of benzene rings due to its ability to improve the physicochemical properties of prospective drug candidates, but studying the SARs of C2-substituted BCPs has been heavily restricted by the need for multistep de novo synthesis of each analogue of interest. Here we report a programmable bis-functionalization strategy to enable late-stage sequential derivatization of BCP bis-boronates, opening up opportunities to explore the SARs of drug candidates possessing multisubstituted BCP motifs. Our approach capitalizes on the inherent chemoselectivity exhibited by BCP bis-boronates, enabling highly selective activation and functionalization of bridgehead (C3)-boronic pinacol esters (Bpin), leaving the C2-Bpin intact and primed for subsequent derivatization. These selective transformations of both BCP bridgehead (C3) and bridge (C2) positions enable access to C1,C2-disubstituted and C1,C2,C3-trisubstituted BCPs that encompass previously unexplored chemical space.

3.
Shock ; 61(3): 414-423, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38150357

RESUMO

ABSTRACT: Posthemorrhagic shock mesenteric lymph (PHSML) return-contributed excessive autophagy of vascular smooth muscle cells (VSMCs) is involved in vascular hyporeactivity, which is inhibited by stellate ganglion block (SGB) treatment. The contractile phenotype of VSMCs transforms into a synthetic phenotype after stimulation with excessive autophagy. Therefore, we hypothesized that SGB ameliorates PHSML-induced vascular hyporeactivity by inhibiting autophagy-mediated phenotypic transformation of VSMCs. To substantiate this hypothesis, a hemorrhagic shock model in conscious rats was used to observe the effects of SGB intervention or intravenous infusion of the autophagy inhibitor 3-methyladenine (3-MA) on intestinal blood flow and the expression of autophagy- and phenotype-defining proteins in mesenteric secondary artery tissues. We also investigated the effects of intraperitoneal administration of PHSML intravenous infusion and the autophagy agonist rapamycin (RAPA) on the beneficial effect of SGB. The results showed that hemorrhagic shock decreased intestinal blood flow and enhanced the expression of LC3 II/I, Beclin 1, and matrix metalloproteinase 2, which were reversed by SGB or 3-MA treatment. In contrast, RAPA and PHSML administration abolished the beneficial effects of SGB. Furthermore, the effects of PHSML or PHSML obtained from rats treated with SGB (PHSML-SGB) on cellular contractility, autophagy, and VSMC phenotype were explored. Meanwhile, the effects of 3-MA on PHSML and RAPA on PHSML-SGB were observed. The results showed that PHSML, but not PHSML-SGB, incubation decreased VSMC contractility and induced autophagy activation and phenotype transformation. Importantly, 3-MA administration reversed the adverse effects of PHSML, and RAPA treatment attenuated the effects of PHSML-SGB incubation on VSMCs. Taken together, the protective effect of SGB on vascular reactivity is achieved by inhibiting excessive autophagy-mediated phenotypic transformation of VSMCs to maintain their contractile phenotype.


Assuntos
Choque Hemorrágico , Ratos , Animais , Choque Hemorrágico/metabolismo , Músculo Liso Vascular , Metaloproteinase 2 da Matriz/farmacologia , Gânglio Estrelado/metabolismo , Fenótipo , Autofagia , Miócitos de Músculo Liso/metabolismo , Células Cultivadas
4.
Acc Chem Res ; 56(24): 3604-3615, 2023 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-38051914

RESUMO

ConspectusCross-coupling methods are the most widely used synthetic methods in medicinal chemistry. Existing reactions are dominated by methods such as amide coupling and arylation reactions that form bonds to sp2-hybridized carbon atoms and contribute to the formation of "flat" molecules. Evidence that three-dimensional structures often have improved physicochemical properties for pharmaceutical applications has contributed to growing demand for cross-coupling methods with sp3-hybridized reaction partners. Substituents attached to sp3 carbon atoms are intrinsically displayed in three dimensions. These considerations have led to efforts to establish reactions with sp3 cross-coupling partners, including alkyl halides, amines, alcohols, and carboxylic acids. As C(sp3)-H bonds are much more abundant that these more conventional coupling partners, we have been pursuing C(sp3)-H cross-coupling reactions that achieve site-selectivity, synthetic utility, and scope competitive with conventional coupling reactions.In this Account, we outline Cu-catalyzed oxidative cross-coupling reactions of benzylic C(sp3)-H bonds with diverse nucleophilic partners. These reactions commonly use N-fluorobenzenesulfonimide (NFSI) as the oxidant. The scope of reactivity is greatly improved by using a "redox buffer" that ensures that the Cu catalyst is available in the proper redox state to promote the reaction. Early precedents of catalytic Cu/NFSI oxidative coupling reactions, including C-H cyanation and arylation, did not require a redox buffer, but reactions with other nucleophiles, such as alcohols and azoles, were much less effective under similar conditions. Mechanistic studies show that some nucleophiles, such as cyanide and arylboronic acids, promote in situ reduction of CuII to CuI, contributing to successful catalytic turnover. Poor reactivity was observed with nucleophiles, such as alcohols, that do not promote CuII reduction in the same manner. This insight led to the identification of sacrificial reductants, termed "redox buffers", that support controlled generation of CuI during the reactions and enable successful benzylic C(sp3)-H cross-coupling with diverse nucleophiles. Successful reactions include those that feature direct coupling of (hetero)benzylic C-H substrates with coupling partners (alcohols, azoles) and sequential C(sp3)-H functionalization/coupling reactions. The latter methods feature generation of a synthetic linchpin that can undergo subsequent reaction with a broad array of nucleophiles. For example, halogenation/substitution cascades afford benzylic amines, (thio)ethers, and heterodiarylmethane derivatives, and an isocyanation/amine-addition sequence generates diverse benzylic ureas.Collectively, these Cu-catalyzed (hetero)benzylic C(sp3)-H cross-coupling reactions rapidly access diverse molecules. Analysis of their physicochemical and topological properties highlights the "drug-likeness" and enhanced three-dimensionality of these products relative to existing bioactive molecules. This consideration, together with the high benzylic C-H site-selectivity and the broad scope of reactivity enabled by the redox buffering strategy, makes these C(sp3)-H cross-coupling methods ideally suited for implementation in high-throughput experimentation platforms to explore novel chemical space for drug discovery and related applications.

5.
Diabetes Metab Syndr ; 17(12): 102907, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37980723

RESUMO

AIMS: Glucagon-like peptide 1 (GLP-1) is produced by the L subtype of enteroendocrine cells (EECs). Patients with type 2 diabetes (T2D) exhibit reduced incretin effect, but the pathophysiology and functional change of the L-cells remain unclear. Deciphering the mechanisms of the biological changes in L-cells under T2D conditions may assist in the research of gut-based strategies for T2D therapy. METHODS: We investigated the fasting serum GLP-1 levels and the distribution of colonic L-cells in young and aged participants with and without T2D. Additionally, we established an aged male T2D Wistar rat model subjected to a long-term high-fat and high-fructose (HFHF) diet. Histological investigations and single-cell RNA sequencing (scRNA-seq) analyses were performed to explore the mechanisms underlying functional changes in the colonic EECs. RESULTS: We observed a decline in circulating GLP-1 levels and a reduced number of colonic L-cells in elderly patients with T2D. The mechanisms underlying impaired L-cell formation and disturbed GLP-1 production were revealed using aged T2D rats induced by a long-term HFHF diet. The scRNA-seq results showed that the transcription factors that regulate L-cell commitment, such as Foxa1, were downregulated, and the expression of genes that participate in encoding GLP-1, GLP-1 posttranslational processing, hormone secretion, and nutrient sensing was disturbed. CONCLUSIONS: Taken together, the reduced L-cell lineage commitment and disturbed L-cell functions might be the major cause of the reduced GLP-1 production in aged populations with T2D. Our study provides new insights for identifying novel targets in colonic L-cells for improving endogenous GLP-1 production.


Assuntos
Diabetes Mellitus Tipo 2 , Peptídeo 1 Semelhante ao Glucagon , Humanos , Camundongos , Idoso , Masculino , Ratos , Animais , Células L , Ratos Wistar , Células Enteroendócrinas/metabolismo , Fator 3-alfa Nuclear de Hepatócito/metabolismo , Fator 3-alfa Nuclear de Hepatócito/farmacologia
6.
Zhongguo Gu Shang ; 36(10): 926-31, 2023 Oct 25.
Artigo em Chinês | MEDLINE | ID: mdl-37881923

RESUMO

OBJECTIVE: To compare the posterior cruciate ligament(PCL) index with six different measurement methods, and analyze and verify its clinical diagnostic value in anterior cruciate ligament (ACL) injury. METHODS: The Magnetic resonance imaging (MRI) data of 225 knee joints in our hospital from May 2018 to March 2022 were retrospectively analyzed, aged from 18 to 60 years old, with a median of 32 years old. On the sagittal MRI images of 114 patients with ACL injury and 111 patients with intact ACL, Measure the straight-line distance (A) between the femoral attachment point and the tibial attachment point of the PCL on the MRI sagittal image and the maximum vertical distance (B) between the straight line and the arcuate mark point of the PCL on the sagittal image, calculate the PCL index and evaluate the diagnostic value of the PCL index for ACL injury. RESULTS: The PCL index of the ACL normal group and the ACL injury group were statistically described. There was no significant difference in PCL index 1, 2, 3 and 6 between the two groups(P>0.05). The difference of PCL index 4 and 5 between the two groups was statistically significant (P<0.001). This study only found that the PCL index 2, 6 in the ACL normal group had a negative correlation with the patient's age (correlation coefficient=-0.213, -0.819;P<0.05), and the PCL index 5 in the ACL injury group was significantly correlated with the patient's body mass index(BMI)had a negative correlation (correlation coefficient=-0.277, P<0.05). CONCLUSION: The change of PCL index is helpful for the diagnosis of ACL injury, PCL index 4 and 5 can be used as effective reference indexes for diagnosing ACL injury in clinic.


Assuntos
Lesões do Ligamento Cruzado Anterior , Ligamento Cruzado Posterior , Humanos , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Ligamento Cruzado Posterior/diagnóstico por imagem , Lesões do Ligamento Cruzado Anterior/diagnóstico por imagem , Ligamento Cruzado Anterior , Estudos Retrospectivos , Articulação do Joelho , Imageamento por Ressonância Magnética/métodos
7.
J Am Chem Soc ; 145(17): 9434-9440, 2023 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-37084265

RESUMO

Copper-catalyzed radical-relay reactions provide a versatile strategy for selective C-H functionalization; however, reactions with peroxide-based oxidants often require excess C-H substrate. Here, we report a photochemical strategy to overcome this limitation by using a Cu/2,2'-biquinoline catalyst that supports benzylic C-H esterification with limiting C-H substrate. Mechanistic studies indicate that blue-light irradiation promotes carboxylate-to-copper charge transfer, reducing resting-state CuII to CuI, which activates the peroxide to generate an alkoxyl radical hydrogen-atom-transfer species. This "photochemical redox buffering" introduces a unique strategy to sustain the activity of Cu catalysts in radical-relay reactions.

8.
Shock ; 59(5): 754-762, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-36840514

RESUMO

ABSTRACT: Background: Hemorrhagic shock-induced acute lung injury (ALI) is commonly associated with the posthemorrhagic shock mesenteric lymph (PHSML) return. Whether excessive autophagy is involved in PHSML-mediated ALI remains unclear. The relationship between estrogen treatment and PHSML or autophagy needs to verify. The current study will clarify the role of estrogen in reducing PHSML-mediated ALI through inhibition of autophagy. Methods: First, a hemorrhagic shock model in conscious rats was used to observe the effects of 17ß-estradiol (E2) on intestinal blood flow, pulmonary function, intestinal and pulmonary morphology, and expression of autophagy marker proteins. Meanwhile, the effect of PHSML and autophagy agonist during E2 treatment was also investigated. Secondly, rat primary pulmonary microvascular endothelial cells were used to observe the effect of PHSML, PHSML plus E2, and E2-PHSML (PHSML obtained from rats treated by E2) on the cell viability. Results: Hemorrhagic shock induced intestinal and pulmonary tissue damage and increased wet/dry ratio, reduced intestinal blood flow, along with pulmonary dysfunction characterized by increased functional residual capacity and lung resistance and decreased inspiratory capacity and peak expiratory flow. Hemorrhagic shock also enhanced the autophagy levels in intestinal and pulmonary tissue, which was characterized by increased expressions of LC3 II/I and Beclin-1 and decreased expression of p62. E2 treatment significantly attenuated these adverse changes after hemorrhagic shock, which was reversed by PHSML or rapamycin administration. Importantly, PHSML incubation decreased the viability of pulmonary microvascular endothelial cells, while E2 coincubation or E2-treated lymph counteracted the adverse roles of PHSML. Conclusions: The role of estrogen reducing PHSML-mediated ALI is associated with the inhibition of autophagy.


Assuntos
Lesão Pulmonar Aguda , Choque Hemorrágico , Ratos , Animais , Ratos Sprague-Dawley , Choque Hemorrágico/complicações , Choque Hemorrágico/tratamento farmacológico , Choque Hemorrágico/metabolismo , Células Endoteliais/metabolismo , Lesão Pulmonar Aguda/tratamento farmacológico , Estrogênios/farmacologia , Estrogênios/uso terapêutico , Autofagia
9.
J Am Chem Soc ; 145(1): 25-31, 2023 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-36548026

RESUMO

Heterocycles are the backbone of modern medical chemistry and drug development. The derivatization of "an olefin" inside aromatic rings represents an ideal approach to access functionalized saturated heterocycles from abundant aromatic building blocks. Here, we report an operationally simple, efficient, and practical method to selectively access hydrosilylated and reduced N-heterocycles from bicyclic aromatics via a key diradical intermediate. This approach is expected to facilitate complex heterocycle functionalizations that enable access to novel medicinally relevant scaffolds.


Assuntos
Quinolinas , Isoquinolinas , Estrutura Molecular , Catálise , Desenvolvimento de Medicamentos
10.
Nat Synth ; 2(10): 998-1008, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38463240

RESUMO

Pharmaceutical and agrochemical discovery efforts rely on robust methods for chemical synthesis that rapidly access diverse molecules1,2. Cross-coupling reactions are the most widely used synthetic methods3, but these methods typically form bonds to C(sp2)-hybridized carbon atoms (e.g., amide coupling, biaryl coupling) and lead to a prevalence of "flat" molecular structures with suboptimal physicochemical and topological properties4. Benzylic C(sp3)-H cross-coupling methods offer an appealing strategy to address this limitation by directly forming bonds to C(sp3)-hybridized carbon atoms, and emerging methods exhibit synthetic versatility that rivals conventional cross-coupling methods to access products with drug-like properties. Here, we use a virtual library of >350,000 benzylic ethers and ureas derived from benzylic C-H cross-coupling to test the widely held view that coupling at C(sp3)-hybridized carbon atoms affords products with improved three-dimensionality. The results show that the conformational rigidity of the benzylic scaffold strongly influences the product dimensionality. Products derived from flexible scaffolds often exhibit little or no improvement in three-dimensionality, unless they adopt higher energy conformations. This outcome introduces an important consideration when designing routes to topologically diverse molecular libraries. The concepts elaborated herein are validated experimentally through an informatics-guided synthesis of selected targets and the use of high-throughput experimentation to prepare a library of three-dimensional products that are broadly distributed across drug-like chemical space.

12.
Brain Res Bull ; 181: 77-86, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35093468

RESUMO

Hormone therapy (HT) has failed to improve learning and memory in postmenopausal women according to recent clinical studies; however, the reason for failure of HT in improving cognitive performance is unknown. In our research, we found cognitive flexibility was improved by 17ß-Estradiol (E2) in mice 1 week after ovariectomy (OVXST), but not in mice 3 months after ovariectomy (OVXLT). Isobaric tags for relative and absolute quantitation (iTRAQ) revealed increased cannabinoid receptor interacting protein 1 (CNRIP1) in E2-treated OVXLT mice compared with E2-treated OVXST mice. Adeno-associated virus 2/9 (AAV2/9) delivery of Cnrip1 short-hairpin small interfering RNA (Cnrip1-shRNA) rescued the impaired cognitive flexibility in E2 treated OVXLT mice. This effect is dependent on CB1 function, which could be blocked by AM251-a CB1 antagonist. Our results indicated a new method to increasing cognitive flexibility in women receiving HT by disrupting CNRIP1.


Assuntos
Antagonistas de Receptores de Canabinoides/farmacologia , Proteínas de Transporte/efeitos dos fármacos , Proteínas de Transporte/metabolismo , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/metabolismo , Estradiol/farmacologia , Terapia de Reposição Hormonal , Córtex Pré-Frontal/efeitos dos fármacos , Animais , Modelos Animais de Doenças , Feminino , Camundongos , Ovariectomia , Piperidinas/farmacologia , Pós-Menopausa , Pirazóis/farmacologia , RNA Interferente Pequeno , Receptor CB1 de Canabinoide/antagonistas & inibidores
13.
Biol Trace Elem Res ; 200(4): 1750-1762, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34185276

RESUMO

Mastitis caused by Staphylococcus aureus infection not only causes serious economic losses, but also affects human health. Se plays an important role in body immunity. However, the mechanisms by which Se regulates mastitis induced by S. aureus are still principally unknown. The purpose of this study is to investigate whether Se can inhibit mastitis induced by S. aureus through regulation of MerTK. Sixty BALB/c female mice were fed low, normal, or high Se concentrations for 7 weeks and then randomly divided into six groups (Se-Low Control group (LSN), Se-Normal Control group (NSN), Se-High Control group (HSN), Se-Low S. aureus group (LSS), Se-Normal S. aureus group (NSS), Se-High S. aureus group (HSS)). The regulation of Se on MerTK was detected via histopathological staining, western blot analysis, enzyme-linked immunosorbent assay, and qRT-PCR. With increased selenium concentrations, the levels of IL-1ß, IL-6, and TNF-α decreased, while the phosphorylation levels of MerTK, PI3K, AKT, and mTOR increased. Therefore, this study showed that Se could alleviate S. aureus mastitis by activating MerTK and PI3K/AKT/mTOR pathway.


Assuntos
Mastite , Selênio , Infecções Estafilocócicas , Animais , Feminino , Humanos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Mastite/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , Selênio/metabolismo , Selênio/farmacologia , Infecções Estafilocócicas/metabolismo , Staphylococcus aureus/metabolismo , Serina-Treonina Quinases TOR , c-Mer Tirosina Quinase
14.
Nat Commun ; 12(1): 5989, 2021 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-34645818

RESUMO

Liquid-liquid phase separation promotes the formation of membraneless condensates that mediate diverse cellular functions, including autophagy of misfolded proteins. However, how phase separation participates in autophagy of dysfunctional mitochondria (mitophagy) remains obscure. We previously discovered that nuclear receptor Nur77 (also called TR3, NGFI-B, or NR4A1) translocates from the nucleus to mitochondria to mediate celastrol-induced mitophagy through interaction with p62/SQSTM1. Here, we show that the ubiquitinated mitochondrial Nur77 forms membraneless condensates capable of sequestrating damaged mitochondria by interacting with the UBA domain of p62/SQSTM1. However, tethering clustered mitochondria to the autophagy machinery requires an additional interaction mediated by the N-terminal intrinsically disordered region (IDR) of Nur77 and the N-terminal PB1 domain of p62/SQSTM1, which confers Nur77-p62/SQSTM1 condensates with the magnitude and liquidity. Our results demonstrate how composite multivalent interaction between Nur77 and p62/SQSTM1 coordinates to sequester damaged mitochondria and to connect targeted cargo mitochondria for autophagy, providing mechanistic insight into mitophagy.


Assuntos
Mitocôndrias/efeitos dos fármacos , Mitofagia/efeitos dos fármacos , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Triterpenos Pentacíclicos/farmacologia , Proteína Sequestossoma-1/genética , Animais , Complexo IV da Cadeia de Transporte de Elétrons , Feminino , Regulação da Expressão Gênica , Genes Reporter , Proteínas de Fluorescência Verde , Células HeLa , Humanos , Proteínas Luminescentes , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitofagia/genética , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Ligação Proteica , Transporte Proteico , Proteínas Recombinantes de Fusão , Reologia , Proteína Sequestossoma-1/metabolismo , Fator de Necrose Tumoral alfa/farmacologia , Proteína Vermelha Fluorescente
15.
J Am Chem Soc ; 143(36): 14438-14444, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34464528

RESUMO

Azoles are important motifs in medicinal chemistry, and elaboration of their structures via direct N-H/C-H coupling could have broad utility in drug discovery. The ambident reactivity of many azoles, however, presents significant selectivity challenges. Here, we report a copper-catalyzed method that achieves site-selective cross-coupling of pyrazoles and other N-H heterocycles with substrates bearing (hetero)benzylic C-H bonds. Excellent N-site selectivity is achieved, with the preferred site controlled by the identity of co-catalytic additives. This cross-coupling strategy features broad scope for both the N-H heterocycle and benzylic C-H coupling partners, enabling application of this method to complex molecule synthesis and medicinal chemistry.


Assuntos
Azóis/síntese química , Compostos de Benzil/química , Catálise , Cobre/química , Indanos/química , Estrutura Molecular , Oxidantes/química , Oxirredução , Sulfonamidas/química
16.
Biol Trace Elem Res ; 199(2): 594-603, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32328968

RESUMO

Selenium (Se) is an essential trace element that maintains normal physiological functions in organisms. Since the discovery of glutathione peroxidase (GSH-PX), public interest in selenoproteins has gradually increased. Based on previous studies, dietary Se maintains erythrocyte homeostasis through selenoprotein-induced mediation of redox reactions. Furthermore, both the surface phosphatidylserine (PS) and intramembrane stomatin contents can be used as indicators of erythrocyte osmotic fragility. This study focused on the mechanism by which dietary Se deficiency increases erythrocyte osmotic fragility. We fed Se-deficient grain to mice for 8 weeks to establish a Se deficiency model in mice. We measured Se levels in the blood as well as the activities of antioxidant enzymes associated with selenoproteins in a Se-deficient environment. We used Western blotting, routine blood analysis, and other methods to detect red blood cell oxidative stress levels, membrane stomatin levels, and PS externalization. Fresh blood was collected to test erythrocyte osmotic fragility. The results showed that antioxidant enzyme activity was affected by dietary Se deficiency. Oxidative stress increased lipid peroxidation and the ROS content in the blood of the mice. Under such conditions, decreased PS exposure and stomatin content in the erythrocyte membrane eventually affected the structure of the erythrocyte membrane and increased erythrocyte osmotic fragility.


Assuntos
Selênio , Animais , Eritrócitos/metabolismo , Glutationa Peroxidase/metabolismo , Peroxidação de Lipídeos , Camundongos , Fragilidade Osmótica , Estresse Oxidativo , Fosfatidilserinas
17.
J Am Chem Soc ; 142(26): 11388-11393, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32539355

RESUMO

Site selectivity represents a key challenge for non-directed C-H functionalization, even when the C-H bond is intrinsically reactive. Here, we report a copper-catalyzed method for benzylic C-H azidation of diverse molecules. Experimental and density functional theory studies suggest the benzyl radical reacts with a CuII-azide species via a radical-polar crossover pathway. Comparison of this method with other C-H azidation methods highlights its unique site selectivity, and conversions of the benzyl azide products into amine, triazole, tetrazole, and pyrrole functional groups highlight the broad utility of this method for target molecule synthesis and medicinal chemistry.


Assuntos
Azidas/síntese química , Compostos de Benzil/química , Cobre/química , Azidas/química , Catálise , Estrutura Molecular
18.
Nat Catal ; 3(4): 358-367, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32368720

RESUMO

Cross-coupling reactions enable rapid, convergent synthesis of diverse molecules and provide the foundation for modern chemical synthesis. The most widely used methods employ sp2-hybridized coupling partners, such as aryl halides or related pre-functionalized substrates. Here, we demonstrate copper-catalysed oxidative cross coupling of benzylic C-H bonds with alcohols to afford benzyl ethers, enabled by a redox-buffering strategy that maintains the activity of the copper catalyst throughout the reaction. The reactions employ the C-H substrate as the limiting reagent and exhibit broad scope with respect to both coupling partners. This approach to direct site-selective functionalization of C(sp3)-H bonds provides the basis for efficient three-dimensional diversification of organic molecules and should find widespread utility in organic synthesis, particularly for medicinal chemistry applications.

19.
Cell Prolif ; 53(3): e12763, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31925859

RESUMO

In recent years, although the development of clinical therapy for diabetic kidney disease (DKD) has made great progress, the progression of DKD still cannot be controlled. Therefore, further study of the pathogenesis of DKD and improvements in DKD treatment are crucial for prognosis. Traditional studies have shown that podocyte injury plays an important role in this process. Recently, it has been found that glomerulotubular balance and tubuloglomerular feedback (TGF) may be involved in the progression of DKD. Glomerulotubular balance is the specific gravity absorption of the glomerular ultrafiltrate by the proximal tubules, which absorbs only 65% to 70% of the ultrafiltrate. This ensures that the urine volume will not change much regardless of whether the glomerular filtration rate (GFR) increases or decreases. TGF is one of the significant mechanisms of renal blood flow and self-regulation of GFR, but how they participate in the development of DKD in the pathological state and the specific mechanism is not clear. Injury to tubular epithelial cells (TECs) is the key link in DKD. Additionally, injury to glomerular endothelial cells (GECs) plays a key role in the early occurrence and development of DKD. However, TECs and GECs are close to each other in anatomical position and can crosstalk with each other, which may affect the development of DKD. Therefore, the purpose of this review was to summarize the current knowledge on the crosstalk between TECs and GECs in the pathogenesis of DKD and to highlight specific clinical and potential therapeutic strategies.


Assuntos
Nefropatias Diabéticas/fisiopatologia , Glomérulos Renais/fisiopatologia , Túbulos Renais/fisiopatologia , Animais , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Progressão da Doença , Endotélio/citologia , Endotélio/metabolismo , Endotélio/patologia , Humanos , Glomérulos Renais/citologia , Glomérulos Renais/metabolismo , Glomérulos Renais/patologia , Túbulos Renais/citologia , Túbulos Renais/metabolismo , Túbulos Renais/patologia , Urotélio/citologia , Urotélio/metabolismo , Urotélio/patologia , Urotélio/fisiopatologia
20.
Ann Transl Med ; 7(14): 322, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31475192

RESUMO

BACKGROUND: We conducted a network meta-analysis (NMA) to evaluate the efficacy and safety of cinacalcet, active vitamin D and cinacalcet plus active vitamin D in the treatment of secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD). METHODS: A systematic literature search was performed using the Cochrane Library, PubMed, EMBASE, Web of Science, Google Scholar, China National Knowledge Internet (CNKI) and Wanfang databases. In total, eight randomized controlled trials (RCTs) with 1,443 patients were eligible for this meta-analysis. Pairwise meta-analysis was performed to evaluate the compliance of intact parathyroid hormone (iPTH), Ca, P, etc., and the mortality and safety of cinacalcet plus active vitamin D and active vitamin D alone. Then, NMA was used to estimate the safety and efficacy of the administration of active vitamin D and different drugs in the control group. RESULTS: The results of the pairwise meta-analysis revealed that compared with active vitamin D monotherapy, cinacalcet plus active vitamin D did not improve the survival of patients but significantly improved the blood calcium compliance rate [relative risk (RR) =1.82, 95% confidence interval (CI): 1.51-2.21, P<0.00001]. Furthermore, it is worth noting that compared with the corresponding incidence with other treatments, the incidence of vomiting was significantly increased with cinacalcet plus active vitamin D treatment (RR =2.07, 95% CI: 1.18-3.65, P=0.01). Through direct and indirect comparisons, the NMA revealed the following results: (I) compared with oral or intravenous (IV) administration of vitamin D, the solely oral administration of active vitamin D increased mortality, and (II) cinacalcet monotherapy increased the risk of hypocalcemia, and that risk was even higher for cinacalcet plus active vitamin D. However, the results should be treated with caution because the prediction interval (PrI) crossed the invalid line. CONCLUSIONS: This pairwise meta-analysis and NMA provided a comprehensive analysis of the currently utilized CKD-SHPT treatment interventions. This network identified some highly ranked interventions through analyses that were included in a small number of trials; these interventions merit further examination on a larger scale in the context of well-designed RCTs.

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