Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 286
Filter
1.
Int J Biol Macromol ; 280(Pt 4): 136161, 2024 Sep 30.
Article in English | MEDLINE | ID: mdl-39357705

ABSTRACT

The lower melt strength of poly(lactide) (PLA) limits its broader applications. Here, a strategy combining copolymerization with multi-arm branching was propose to enhance the melt strength of PLA. Initially, stereoisomeric cyclic ester monomers (CEM) synthesized via zeolite catalysis were copolymerized into PLA chains. Subsequently, rheological testing revealed that the zero-shear viscosity (η0) of linear PLA increased by 467 % with only 1 mol% of CEM units. Our study further systematically explored the relationship between the side group structure and chirality of the comonomers and the rheological properties of the copolymers. CEMs with long-chain branched structures and opposite chirality had the best enhancement effect. In order to further enhance the melt strength, we successfully achieved alterations in polymer topology by employing trimethylolpropane as an initiator, corresponding three-arm copolymers achieve up to a 67-fold increase in η0 (1.0 kPa∙s to 68.1 kPa∙s). Tensile tests indicated that the mechanical properties of the copolymers were comparable to those of PLA, with a tensile strength of approximately 65 MPa. Additionally, due to the high melt strength, we successfully produced closed-cell PLA-based foam materials with uniform pore sizes. In summary, this study furnishes a feasible method for designing polymer materials possessing the desired melt strength.

2.
Cell Rep Med ; : 101757, 2024 Sep 27.
Article in English | MEDLINE | ID: mdl-39368483

ABSTRACT

Chordoma is a rare and heterogeneous mesenchymal malignancy, with distinct clinical and biological behaviors. Till now, its comprehensive clinical-molecular characteristics and accurate molecular classification remain obscure. In this research, we enroll 102 patients with chordoma and describe their clinical, imageological, and histopathological features. Through tandem mass tag-based proteomic analysis and nonnegative matrix factorization clustering, we classify chordoma into three molecular subtypes: bone microenvironment-dominant, mesenchymal-derived, and mesenchymal-to-epithelial transition-mediated pattern. The three subtypes exhibit discrete clinical prognosis and distinct biological attributes of osteoclastogenesis and immunogenicity, oxidative phosphorylation, and receptor tyrosine kinase activation, suggesting targeted therapeutic strategies of denosumab, S-Gboxin, and anlotinib, respectively. Notably, these approaches demonstrate positive treatment outcomes for each subtype in vitro and in vivo. Altogether, this work sheds light on the clinical-proteomic characteristics of chordoma and provides a candidate precision treatment strategy for chordoma according to molecular classification, underscoring their potential for clinical application.

3.
Diabetes Metab ; : 101583, 2024 Oct 08.
Article in English | MEDLINE | ID: mdl-39389218

ABSTRACT

AIM: Perirenal fat (PRF) is an independent predictor for chronic kidney disease (CKD) in type 2 diabetes mellitus (T2DM) patients. Previous studies speculated that PRF may promote renal dysfunction through affecting renal hemodynamics. To verify this hypothesis, we studied the relationship between PRF and renal hemodynamics in T2DM. METHODS: 91 T2DM patients were included. PRF thickness (PRFT) was measured by magnetic resonance imaging. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were determined by renal dynamic imaging. Renal vascular resistance (RVR), glomerular hydrostatic pressure (PGLO), afferent (RA) and efferent (RE) arteriolar resistance were calculated by Gomez equations. Multiple linear regression was used to determine the relationship between PRFT and renal hemodynamics. Mediation analysis was conducted to estimate the mediation effects of renal hemodynamics on the relationship between PRF and CKD. RESULTS: All patients were divided into three groups according to the tertiles of PRFT. Compared with patients in tertile 1, GFR and ERPF were significantly decreased in patients in tertile 3, while RVR and RA were significantly increased. PRFT was negatively correlated with GFR, ERPF and PGLO, and positively correlated with RVR and RA after adjustment for sex, age, visceral adipose tissue and treatments with ACE inhibitors/angiotensin receptor blockers and sodium-glucose cotransporter protein-2 inhibitors. Moreover, RVR and RA mediated the effect of PRF on GFR, with a mediated proportion of 29.1% and 41.4% respectively. CONCLUSION: In T2DM patients, PRF was negatively correlated with GFR, and positively correlated with RA. RA mediated the relationship between PRF and CKD.

4.
Diabetes Metab Syndr ; 18(9): 103127, 2024 Sep 24.
Article in English | MEDLINE | ID: mdl-39332264

ABSTRACT

BACKGROUND AND AIMS: The relationship between cereals intake and diabetes is unclear. We aimed to explore associations between individual cereals intake and risks of incident and progression of diabetes. METHODS: We included 502,490 participants from UK Biobank at baseline. A single touchscreen food frequency questionnaire was used to estimate the intake of individual cereals (bran, biscuit, oat, muesli, and other cereals). Main outcomes included incident diabetes and diabetic complications of cardiovascular disease (CVD), chronic kidney disease (CKD) and diabetic retinopathy (DR). Polygenic risk score (PRS) of glycosylated hemoglobin (HbA1c) was calculated for mediating effects analysis. RESULTS: Among participants without diabetes, when compared to subjects who never had cereals, hazard ratios (95%CI) of developing diabetes in those who had ≥6 bowls/week were 0.72 (0.67-0.78) for bran, 0.86 (0.81-0.92) for biscuit, 0.75(0.66-0.84) for oat, and 0.57(0.53,0.61) for muesli. Among people with diabetes without CVD, a higher intake of aforementioned four individual cereals was associated with a 13%-32 % lower risk of developing CVD. Among people with diabetes without CKD, a higher intake of aforementioned four individual cereals was associated with a 9%-28 % lower risk of developing CKD. We observed a significant mediating effect of the PRS of HbA1c for the association between aforementioned four individual cereals and developing diabetes. CONCLUSION: A higher consumption of cereals was significantly associated with lower risks of diabetes and diabetic complications. Polygenic of HbA1c mediates the effect of cereals on incident diabetes.

5.
Obes Res Clin Pract ; 2024 Sep 16.
Article in English | MEDLINE | ID: mdl-39289047

ABSTRACT

BACKGROUND: It is generally known that although a connection between abdominal obesity and chronic kidney disease (CKD) is well-established, there is a lack of systematic research investigating the specific roles of serum metabolites, including lipid metabolites, amino acid metabolites, carbohydrate metabolites and inflammatory substances in explaining this associations. METHODS: We included 118,020 general patients with data of serum metabolites from UK Biobank. We defined abdominal obesity and CKD based on waist circumference and ICD-10 criteria. The serum metabolites were assessed by a high-throughput nuclear magnetic resonance (NMR) based metabolic biomarker profiling platform. We conducted mediation analysis by R software and used the proportion of mediation to quantify the mediation effect. RESULTS: This study demonstrated that lipid metabolites played a more important role in mediating the relationship between abdominal obesity and CKD than amino acid metabolites and carbohydrate metabolites. And Glycoprotein Acetyls (GlycA) was the strongest mediator for the correlation between abdominal obesity and CKD, accounting for 26.4 %. And In the mediation analysis stratified by sex, we found that the mediating effects of lipid metabolites were mostly higher in men than in women, while GlycA accounted for the largest proportion of the mediation association in both two groups (31.0 % for women and 19.8 % for men). CONCLUSION: Among lipid metabolites, amino acid metabolites, carbohydrate metabolites and inflammatory substances, our study showed that infammation marker GlycA was the novel and key mediator for the correlation between abdominal obesity and CKD.

6.
Drugs ; 2024 Sep 23.
Article in English | MEDLINE | ID: mdl-39312177

ABSTRACT

BACKGROUND: Although a range of renin-angiotensin-aldosterone system (RAAS) modulators are available for blood pressure lowering, the optimal choice within this class remains unclear. We aimed to compare the efficacy and safety of RAAS modulators in the adult hypertensive population. METHODS: A systematic literature search was performed in PubMed, CENTRAL, and Embase. The primary efficacy outcome was all-cause mortality and the secondary efficacy outcome was cardiovascular mortality. Tolerability outcome was discontinuation due to adverse events. Safety outcomes included the occurrence of cough, dizziness, edema, hyperkalemia, and hypotension. Network meta-analyses were performed utilizing a random-effects model within a frequentist framework. RESULTS: We finally identified 51 articles from 49 randomized controlled trials. When compared to placebo, mineralocorticoid receptor antagonists (MRAs) significantly reduced the risk of all-cause mortality (odds ratio (OR) 0.83; 95% confidence interval (CI) 0.74-0.92) and cardiovascular mortality (OR 0.79; 95% CI 0.68-0.93), while none of other RAAS modulators significantly lowered the risk of all-cause or cardiovascular mortality. Individual comparisons indicated that MRAs were associated with a significantly lower risk of all-cause mortality than the other RAAS modulators (reduction: 16% compared with angiotensin-converting enzyme inhibitors (ACEIs), 14% compared with angiotensin receptor blockers (ARBs), and 22% compared with direct renin inhibitors (DRIs)). No difference in discontinuation due to adverse events was found in a comparison of RAAS modulators with placebo. With regard to safety outcomes, ACEIs have a higher risk of cough (OR 4.68; 95% CI 1.61-13.60), ARBs have a higher risk of dizziness (OR 1.42; 95% CI 1.06-1.91), hypotension (OR 2.10; 95% CI 1.02-4.34), and hyperkalemia (OR 1.99; 95% CI 1.17-3.41), and MRAs had a higher risk of hyperkalemia (OR 2.68; 95% CI 1.99-3.62) when compared to placebo. CONCLUSIONS: MRAs were the only RAAS modulators with a survival benefit in adults with hypertension, although they carried a higher risk of hyperkalemia. Our data challenge current hypertension guidelines which recommend MRAs as fourth-line therapy, and suggest that MRAs should be prescribed earlier and more widely. REGISTRATION: PROSPERO identifier number CRD42023405714.

7.
Nat Commun ; 15(1): 7952, 2024 Sep 11.
Article in English | MEDLINE | ID: mdl-39261450

ABSTRACT

The relationship between psoriasis and site-specific cancers remains unclear. Here, we aim to investigate whether psoriasis is causally associated with site-specific cancers. We use observational and genetic data from the UK Biobank, obtaining GWAS summary data, eQTL analysis data, TCGA data, and GTEx data from public datasets. We perform PheWAS, polygenic risk score analysis, and one-sample and two-sample Mendelian randomization analyses to investigate the potential causal associations between psoriasis and cancers. In the unselected PheWAS analysis, psoriasis is associated with higher risks of 16 types of cancer. Using one-sample Mendelian randomization analyses, it is found that genetically predicted psoriasis is associated with higher risks of anal canal cancer, breast cancer, follicular non-Hodgkin's lymphoma and nonmelanoma skin cancer in women; and lung cancer and kidney cancer in men. Our two-sample Mendelian randomization analysis indicates that psoriasis is causally associated with breast cancer and lung cancer. Gene annotation shows that psoriasis-related genes, such as ERAP1, are significantly different in lung and breast cancer tissues. Taken together, clinical attention to lung cancer and breast cancer may be warranted among patients with psoriasis.


Subject(s)
Genetic Predisposition to Disease , Genome-Wide Association Study , Mendelian Randomization Analysis , Psoriasis , Humans , Psoriasis/genetics , Psoriasis/epidemiology , Female , Male , Neoplasms/genetics , Neoplasms/epidemiology , Polymorphism, Single Nucleotide , Risk Factors , Breast Neoplasms/genetics , Breast Neoplasms/epidemiology , United Kingdom/epidemiology , Lung Neoplasms/genetics , Lung Neoplasms/epidemiology , Middle Aged , Quantitative Trait Loci , Multifactorial Inheritance/genetics
8.
Endocrine ; 85(3): 1417-1424, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39009922

ABSTRACT

BACKGROUND: Captopril challenge test (CCT), seated saline infusion test (SSIT), oral sodium loading test (OSLT) and fludrocortisone suppression test (FST) are widely used diagnostic tests for primary aldosteronism (PA). These tests differ in terms of safety and complexity. Whether the simpler tests (CCT and SSIT) are comparable in diagnostic performance to the more complex ones (FST and OSLT) is unclear. PURPOSE: To compare the diagnostic accuracy of the four tests. METHODS: This is a retrospective study of hypertensive patients who were screened for PA and completed at least one confirmatory test. The patients were divided into two cohorts: one including those who completed one to three tests was used for the estimation of sensitivity and specificity. The other including those who completed four tests was used for the comparison of accuracy. Bayesian method was used to obtain the sensitivity, specificity, and Youden index of each test. RESULTS: The study included 1011 hypertensive patients. Among them, 895 patients completed one to three tests (including 889 CCT, 605 FST, 611 SSIT and 69 OSLT), and 116 patients completed four tests. SSIT had the highest sensitivity of 0.82(95% CI 0.78-0.86) but the lowest specificity of 0.76(0.70-0.80). OSLT had the lowest sensitivity of 0.65(0.56-0.75) but the highest specificity of 0.91(0.82-0.96). The sensitivity and specificity were 0.78 (95% CI, 0.75-0.82), 0.82 (95% CI, 0.78-0.85), for CCT, and 0.77 (95% CI, 0.73-0.81), 0.87 (95% CI, 0.82-0.91) for FST, respectively. The Youden index was not significantly different among the four tests[0.60(0.55-0.65) for CCT; 0.58(0.51-0.64) for SSIT; (0.64(0.57-0.69) for FST; 0.56(0.43-0.67) for OSLT]. CONCLUSION: The accuracy of simpler tests is comparable to the more complex ones. Considering the safety and simplicity of CCT, it may be a reasonable first choice when confirming the diagnosis of PA.


Subject(s)
Bayes Theorem , Hyperaldosteronism , Sensitivity and Specificity , Humans , Hyperaldosteronism/diagnosis , Hyperaldosteronism/blood , Middle Aged , Male , Female , Retrospective Studies , Adult , Hypertension/diagnosis , Aged , Captopril , Fludrocortisone/therapeutic use
9.
ACS Nano ; 18(32): 21491-21503, 2024 Aug 13.
Article in English | MEDLINE | ID: mdl-39082107

ABSTRACT

Hard carbon (HC) is a promising anode material for sodium-ion batteries. However, the intrinsic relationship between the closed pores/surface groups and sodium storage performance has been unclear, leading to difficulties in targeted regulation. In this study, renewable tannin extracts were used as raw materials to prepare HC anodes with abundant tunable closed pores and carbonyl groups through a pyrolytic modulation strategy. Combining ex situ characterizations reveals that closed pores and carbonyl groups are regulated by the pyrolytic process. Further, it is demonstrated that the plateau region is mainly contributed by the closed pores; highly stable fluorine-rich solid electrolyte interphase compositions are produced through carbonyl-induced interfacial catalysis. The optimized HC anode displays good cycling stability, exhibiting a high reversible capacity (360.96 mAh g-1) at 30 mA g-1 and capacity retention of up to 94% after 500 cycles at 1 A g-1. Moreover, the full battery assembled with Na3V2(PO4)3/C demonstrates a stable cycling performance. These findings provide a fresh knowledge of the structural design of high-performance HC anode materials and the mechanism of sodium storage in HC.

10.
Endocrine ; 85(3): 1398-1406, 2024 Sep.
Article in English | MEDLINE | ID: mdl-38914747

ABSTRACT

PURPOSE: Adrenal venous sampling (AVS) is recommended for subtyping primary aldosteronism (PA). However, in cases of PA, concurrent subclinical Cushing's syndrome (SCS) has the potential to confound AVS results. Pentixafor, a CXC chemokine receptor type 4-specific ligand, has been reported as a promising marker to evaluate functional nature of adrenal adenomas. This study aims to investigate the clinical value of Gallium-68 Pentixafor Positron Emission Tomography-Computed Tomography (68Ga-Pentixafor PET/CT) in the localization diagnosis of patients with PA plus SCS. METHODS: Two patients with a confirmed diagnosis of PA plus SCS underwent AVS and 68Ga-Pentixafor PET/CT. RESULTS: AVS results revealed no lateralization for both patients while 68Ga-Pentixafor PET/CT showed a unilateral adrenal nodule with increased uptake of 68Ga-Pentixafor. Unilateral adrenalectomy was performed based on the results of 68Ga-Pentixafor PET/CT. Subsequently, complete biochemical remission of autonomous aldosterone and cortisol secretion were achieved in both cases. CONCLUSIONS: 68Ga-Pentixafor PET/CT shows promising potential for the localization of aldosterone and cortisol co-secreting adrenal adenoma in patients with PA plus SCS.


Subject(s)
Cushing Syndrome , Hyperaldosteronism , Positron Emission Tomography Computed Tomography , Humans , Positron Emission Tomography Computed Tomography/methods , Cushing Syndrome/diagnostic imaging , Cushing Syndrome/diagnosis , Cushing Syndrome/blood , Hyperaldosteronism/complications , Hyperaldosteronism/diagnostic imaging , Hyperaldosteronism/diagnosis , Hyperaldosteronism/blood , Middle Aged , Male , Female , Peptides, Cyclic , Coordination Complexes , Adult , Adrenalectomy
11.
Molecules ; 29(12)2024 Jun 19.
Article in English | MEDLINE | ID: mdl-38930971

ABSTRACT

The direct 1,6-nucleophilic difluoromethylation, trifluoromethylation, and difluoroalkylation of para-quinone methides (p-QMs) with Me3SiRf (Rf = CF2H, CF3, CF2CF3, CF2COOEt, and CF2SPh) under mild conditions are described. Although Me3SiCF2H shows lower reactivity than Me3SiCF3, it can react with p-QMs promoted by CsF/18-Crown-6 to give structurally diverse difluoromethyl products in good yields. The products can then be further converted into fluoroalkylated para-quinone methides and α-fluoroalkylated diarylmethanes.

12.
Acta Pharm Sin B ; 14(6): 2598-2612, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38828149

ABSTRACT

Src homology 2 domain-containing tyrosine phosphatase 2 (SHP2) is an essential tyrosine phosphatase that is pivotal in regulating various cellular signaling pathways such as cell growth, differentiation, and survival. The activation of SHP2 has been shown to have a therapeutic effect in colitis and Parkinson's disease. Thus, the identification of SHP2 activators and a complete understanding of their mechanism is required. We used a two-step screening assay to determine a novel allosteric activator of SHP2 that stabilizes it in an open conformation. Oleanolic acid was identified as a suitable candidate. By binding to R362, K364, and K366 in the active center of the PTP domain, oleanolic acid maintained the active open state of SHP2, which facilitated the binding between SHP2 and its substrate. This oleanolic acid-activated SHP2 hindered Th17 differentiation by disturbing the interaction between STAT3 and IL-6Rα and inhibiting the activation of STAT3. Furthermore, via the activation of SHP2 and subsequent attenuation of the STAT3-Th17 axis, oleanolic acid effectively mitigated colitis in mice. This protective effect was abrogated by SHP2 knockout or administration of the SHP2 inhibitor SHP099. These findings underscore the potential of oleanolic acid as a promising therapeutic agent for treating inflammatory bowel diseases.

13.
Materials (Basel) ; 17(9)2024 Apr 30.
Article in English | MEDLINE | ID: mdl-38730920

ABSTRACT

Membrane emulsification technology has garnered increasing interest in emulsion preparation due to controllable droplet size, narrower droplet size distribution, low energy consumption, simple process design and excellent reproducibility. Nevertheless, the pore structure and surface engineering in membrane materials design play a crucial role in achieving high-quality emulsions with high throughput simultaneously. In this work, an oriented interpenetrating capillary network composed of highly aligned and interconnected wood cell lumens has been utilized to fabricate an emulsion membrane. A novel honeycomb porous ZnO layer obtained by a seed prefabrication-hydrothermal growth method was designed to reconstruct wood channel surfaces for enhanced microfluid mixing. The results show that through the unique capillary mesh microstructure of wood, the emulsion droplets were smaller in size, had narrower pore-size distribution, and were easy to obtain under high throughput conditions. Meanwhile, a well-designed ZnO layer could further improve the emulsion quality of a wood membrane, while the emulsifying throughput is still maintained at a higher level. This demonstrates that the convection process of the microfluid in these wood capillary channels was intensified markedly. This study not only develops advanced membrane materials in emulsion preparation, but also introduces a brand-new field for functional applications of wood.

14.
Front Oncol ; 14: 1358422, 2024.
Article in English | MEDLINE | ID: mdl-38577343

ABSTRACT

Prostate cancer is a major contributor to male cancer-related mortality globally. It has a particular affinity for the skeletal system with metastasis to bones seriously impacting prognosis. The identification of prostate cancer biomarkers can significantly enhance diagnosis and patient monitoring. Research has found that cancer and metastases exhibit abnormal expression of numerous non-coding RNA. Some of these RNA facilitate prostate cancer bone metastasis by activating downstream signaling pathways, while others inhibit this process. Elucidating the functional processes of non-coding RNA in prostate cancer bone metastasis will likely lead to innovative treatment strategies for this malignant condition. In this review, the mechanistic role of the various RNA in prostate cancer is examined. Our goal is to provide a new avenue of approach to the diagnosis and treatment of bone metastasis in this cancer.

15.
Materials (Basel) ; 17(6)2024 Mar 16.
Article in English | MEDLINE | ID: mdl-38541515

ABSTRACT

Plastic pollution, particularly microplastic (MP) and nanoplastic (NP) pollution, has become a significant concern. This study explores the use of porous wood for filtration to remove MPs and NPs and investigates their removal mechanisms. Undecorated fir wood with a thickness of 4 mm achieves a 91% removal rate for model polystyrene (PS) MPs (2.6 µm) at a water flux of 198 L/m2h. However, its separation performance for NPs (255.8 and 50.9 nm) is poor. It also shows that fir wood (coniferous wood) has a higher PS removal rate than poplar wood (hard wood). With poly dimethyl diallyl ammonium chloride (PDDA) modification, both MPs and NPs are effectively removed, with NPs' removal rate increasing from <10% to 90% for PDDA/wood. Characterization results reveal that size-exclusive interception dominates for micron-sized particles, and electrostatic interaction is crucial for nanosized particles. Additionally, intercepted NPs have been used as a strong binder for hot-pressed wood to remarkably enhance the mechanical properties of wood, suggesting a novel recycle utilization of discarded wood filters. Overall, this renewable wood material offers a simple solution for tackling MP/NP pollution.

16.
J Insect Physiol ; 154: 104630, 2024 05.
Article in English | MEDLINE | ID: mdl-38432606

ABSTRACT

Beetle elytra act as natural protective covers and effectively shield their flexible abdomens and fragile hindwings from damage. The existing studies have attributed this contribution of the elytra to its honeycomb structures. In this combined experimental and theoretical study, we used the seven-spotted ladybird beetle to demonstrate that both biological morphology and the hollow structure of the dome-like elytra combined to reduce damage during falling. The falling ladybird beetles had a high probability (59.52%) of hitting the ground with the costal edge of the elytra. This strategy could assist with converting the translational energy into rotational kinetic energy, resulting in the reduction of the impulse during falling. In addition, the hollow structures on the elytra could further absorb the residual impact energy. In the future, this biological paradigm could be used as a basis for the development of falling/landing techniques for advanced robots.


Subject(s)
Coleoptera , Animals , Coleoptera/anatomy & histology , Wings, Animal/anatomy & histology , Proteomics
17.
Angew Chem Int Ed Engl ; 63(19): e202401091, 2024 May 06.
Article in English | MEDLINE | ID: mdl-38489249

ABSTRACT

Ligand coupling on hypervalent main group elements has emerged as a pivotal methodology for the synthesis of functionalized N-heteroaromatic compounds in recent years due to the avoidance of transition metals and the mildness of the reaction conditions. In this direction, the reaction of N-heteroaryl sulfur(IV) and N-heteroaryl phosphorus(V) compounds has been well studied. However, the ligand coupling of sulfur(VI) is still underdeveloped and the reaction of alkyl N-heteroarylsulfones is still elusive, which does not match the high status of sulfones as the chemical chameleons in organic synthesis. Here we present a ligand coupling-enabled formal SO2 extrusion of fluoroalkyl 2-azaheteroarylsulfones under the promotion of Grignard reagents, which not only enriches the chemistry of sulfones, but also provides a novel and practical synthetic tool towards N-heteroaromatic fluoroalkylation.

18.
Acc Chem Res ; 57(5): 693-713, 2024 Mar 05.
Article in English | MEDLINE | ID: mdl-38354302

ABSTRACT

ConspectusAs fluorine has played an increasingly important role in modulating the physical, chemical, and biological properties of organic molecules, the selective introduction of fluorine atom(s) or fluorinated moieties into target molecules has become a powerful tool in the development of new pharmaceuticals, agrochemicals, and functional materials. In this context, the difluoromethylene (CF2) and difluoromethyl (CF2H) groups are of special interest because of their ability to serve as bioisosteres of ethereal oxygen atoms and hydroxyl (OH) and thiol (SH) groups, respectively. Difluorocarbene is one of the most versatile reactive intermediates to incorporate CF2 and CF2H groups; however, before 2006, most of the previously known difluorocarbene reagents suffered from several drawbacks such as using ozone-depleting substances (ODSs), difficult-to-handle reagents, or harsh reaction conditions or having narrow substrate scope and/or low yields. Moreover, the reactivity of difluorocarbene generated from different precursors (reagents) was often unpredictable, since the difluorocarbene generation conditions (activation modes) of various difluorocarbene precursors are different, and these conditions may mismatch those required for subsequent difluorocarbene-involved transformations. Therefore, the development of new environmentally friendly and versatile difluorocarbene reagents, as well as the investigation of the mechanistic insights into difluorocarbene-involved reactions, has been highly desirable.In this Account, we summarize our contributions to the development of new difluorocarbene reagents and their applications in organic synthesis since 2006. We have developed seven new difluorocarbene reagents, including 2-chloro-2,2-difluoroacetophenone (1), chlorodifluoromethyl phenyl sulfone (2), S-difluoromethyl-S-phenyl-N-tosylsulfoximine (3), difluoromethyltri(n-butyl)ammonium chloride (4), (chlorodifluoromethyl)trimethylsilane (TMSCF2Cl, 5), (bromodifluoromethyl)trimethylsilane (TMSCF2Br, 6), and (trifluoromethyl)trimethylsilane (TMSCF3, 7). In this journey, we realized the key factor for an ideal difluorocarbene reagent that can be used for a broad range of reactions, that is, the reagent should allow various activation modes for the generation of difluorocarbene species, such as under basic/acidic/neutral conditions, at wide range of temperatures, and in different solvents, which are compatible with a wide range of difluorocarbene-involved transformations. Among all known difluorocarbene reagents, silanes TMSCF2X (X = Br, F, Cl) have stood out as privileged ones, which paves a new avenue for further developing difluorocarbene chemistry. In particular, TMSCF2Br was recognized as an "all-rounder": TMSCF2Br can be applied in almost all common difluorocarbene-involved reactions, and more importantly, TMSCF2Br also enables many other novel transformations that other difluorocarbene reagents cannot achieve, thanks to its unique structure and rich activation modes of releasing difluorocarbene under different reaction conditions. It can be expected that with the commercial availability of TMSCF2X reagents (X = Br, F, Cl) now, the development of difluorocarbene chemistry will be accelerated in the years to come.

19.
Angew Chem Int Ed Engl ; 63(14): e202400839, 2024 Apr 02.
Article in English | MEDLINE | ID: mdl-38358953

ABSTRACT

A new method of constructing "ArSCF2CF2Cu" from ArSCu and TMSCF2Br (TMS=trimethylsilyl) has been developed. The cross-coupling reactions of the obtained "ArSCF2CF2Cu" with diverse aryl iodides (Ar'I) provide an efficient access to Ar'CF2CF2SAr. Mechanistic studies demonstrate that the "ArSCF2CF2Cu" species were generated through controllable double difluoromethylene insertions into ArS-Cu bonds rather than the 1,2-addition of ArSCu to tetrafluoroethylene.

20.
FEBS J ; 291(10): 2221-2241, 2024 May.
Article in English | MEDLINE | ID: mdl-38400523

ABSTRACT

It was reported that the Wnt/ß-catenin pathway is involved in the regulation of aerobic glycolysis and that brain glycolytic dysfunction results in the development of Alzheimer's disease (AD). Icariin (ICA), an active component extracted from Epimedii Folium, has been reported to produce neuroprotective effects in multiple models of AD, but its underlying mechanism remains to be fully described. We aimed to investigate the protective effects of ICA on animal and cell models of AD and confirm whether the Wnt/ß-catenin pathway has functions in the neuroprotective function of ICA. The 3 × Tg-AD mice were treated with ICA. HT22 cells, the Aß25-35 peptide and Dickkopf-1 (DKK1) agent (a specific inhibitor of the Wnt/ß-catenin pathway) were used to further explore the underlying mechanism of ICA that produces anti-AD effects. Behavioral examination, western blotting assay, staining analysis, biochemical test, and lactate dehydrogenase (LDH) assays were applied. We first demonstrated that ICA significantly improved cognitive function and autonomous behavior, reduced neuronal damage, and reversed the protein levels and activities of glycolytic key enzymes, and expression of protein molecules of the canonical Wnt signaling pathway, in 3 × Tg-AD mice back to wild-type levels. Next, we further found that ICA increased cell viability and effectively improved the dysfunctional glycolysis in HT22 cells injured by Aß25-35. However, when canonical Wnt signaling was inhibited by DKK1, the above effects of ICA on glycolysis were abolished. In summary, ICA exerts neuroprotective effects in 3 × Tg-AD animals and AD cellular models by enhancing the function of glycolysis through activation of the Wnt/ß-catenin pathway.


Subject(s)
Alzheimer Disease , Flavonoids , Glycolysis , Mice, Transgenic , Wnt Signaling Pathway , Animals , Male , Mice , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Amyloid beta-Peptides/metabolism , beta Catenin/metabolism , beta Catenin/genetics , Disease Models, Animal , Flavonoids/pharmacology , Glycolysis/drug effects , Intercellular Signaling Peptides and Proteins/metabolism , Intercellular Signaling Peptides and Proteins/genetics , Neuroprotective Agents/pharmacology , Peptide Fragments/metabolism , Wnt Signaling Pathway/drug effects
SELECTION OF CITATIONS
SEARCH DETAIL