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1.
ACS Chem Neurosci ; 15(3): 656-670, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38206798

RESUMO

Ganglioside GAA-7 exhibits higher neurite outgrowth than ganglioside GM1a and most echinodermatous gangliosides (EGs) when tested on neuron-like rat adrenal pheochromocytoma (PC12) cells in the presence of nerve growth factor (NGF). The unique structure of GAA-7 glycan, containing an uncommon sialic acid (8-O-methyl-N-glycolylneuraminic acid) and sialic acid-α-2,3-GalNAc linkage, makes it challenging to synthesize. We recently developed a streamlined method to chemoenzymatically synthesize GAA-7 glycan and employed this modular strategy to efficiently prepare a library of GAA-7 glycan analogues incorporating N-modified or 8-methoxyl sialic acids. Most of these synthetic glycans exhibited moderate efficacy in promoting neuronal differentiation of PC12 cells. Among them, the analogue containing common sialic acid shows greater potential than the GAA-7 glycan itself. This result reveals that methoxy modification is not essential for neurite outgrowth. Consequently, the readily available analogue presents a promising model for further biological investigations.


Assuntos
Ácido N-Acetilneuramínico , Neurônios , Ratos , Animais , Ácido N-Acetilneuramínico/metabolismo , Neurônios/metabolismo , Gangliosídeos/metabolismo , Polissacarídeos/metabolismo , Células PC12 , Neuritos/metabolismo
2.
Sensors (Basel) ; 24(2)2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38257642

RESUMO

This research is dedicated to developing an automatic landing system for shipborne unmanned aerial vehicles (UAVs) based on wireless precise positioning technology. The application scenario is practical for specific challenging and complex environmental conditions, such as the Global Positioning System (GPS) being disabled during wartime. The primary objective is to establish a precise and real-time dynamic wireless positioning system, ensuring that the UAV can autonomously land on the shipborne platform without relying on GPS. This work addresses several key aspects, including the implementation of an ultra-wideband (UWB) circuit module with a specific antenna design and RF front-end chip to enhance wireless signal reception. These modules play a crucial role in achieving accurate positioning, mitigating the limitations caused by GPS inaccuracy, thereby enhancing the overall performance and reception range of the system. Additionally, the study develops a wireless positioning algorithm to validate the effectiveness of automatic landing on the shipborne platform. The platform's wave vibration is considered to provide a realistic landing system for shipborne UAVs. The UWB modules are practically installed on the shipborne platform, and the UAV and the autonomous three-body vessel are tested simultaneously in the outdoor open water space to verify the functionality, precision, and adaptability of the proposed UAV landing system. Results demonstrate that the UAV can autonomously fly from 200 m, approach, and automatically land on the moving shipborne platform without relying on GPS.

3.
ACS Omega ; 8(44): 41855-41864, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37970022

RESUMO

A one-step method for synthesizing 3-(Fmoc-amino acid)-3,4-diaminobenzoic acids was used to prepare preloaded diaminobenzoate resin. The coupling of free diaminobenzoic acid and Fmoc-amino acids gave pure products in 40-94% yield without any purification step in addition to precipitation except for histidine. For the proline residue, crude products were collected and used for solid-phase peptide synthesis to give a moderate yield of a pentapeptide. In addition, this method was used to prepare unusual amino acid derivatives, namely, (2-naphthyl) alanine and 6-aminohexanoic acid derivatives, in 50 and 65% yield, respectively.

4.
Dev Cell ; 58(22): 2447-2459.e5, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-37989081

RESUMO

Glycosphingolipids (GSLs) display diverse functions during embryonic development. Here, we examined the GSL profiles of extracellular vesicles (EVs) secreted from human embryonic stem cells (hESCs) and investigated their functions in priming macrophages to enhance immune tolerance of embryo implantation. When peripheral blood mononuclear cells were incubated with ESC-secreted EVs, globo-series GSLs (GHCer, SSEA3Cer, and SSEA4Cer) were transferred via EVs into monocytes/macrophages. Incubation of monocytes during their differentiation into macrophages with either EVs or synthetic globo-series GSLs induced macrophages to exhibit phenotypic features that imitate immune receptivity, i.e., macrophage polarization, augmented phagocytic activity, suppression of T cell proliferation, and the increased trophoblast invasion. It was also demonstrated that decidual macrophages in first-trimester tissues expressed globo-series GSLs. These findings highlight the role of globo-series GSLs via transfer from EVs in priming macrophages to display decidual macrophage phenotypes, which may facilitate healthy pregnancy.


Assuntos
Glicoesfingolipídeos , Leucócitos Mononucleares , Gravidez , Feminino , Humanos , Macrófagos , Diferenciação Celular , Tolerância Imunológica
5.
Glycoconj J ; 40(5): 551-563, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37606864

RESUMO

Globo A is a neutral Globo-series glycosphingolipid (GSL) that shows natural properties of a cytotoxicity receptor NKp44 binding ligand. The highly complex heptasaccharide glycan structure of Globo A combined with its biological profile provides a unique target for the development of a synthetic method to facilitate its bioactivity studies. Here, a concise chemoenzymatic route to the synthesis of Globo A and its α1,3-galactose-linked congener Globo B is reported. The key to success was the use of a synthetic azido ß-Globo H sphingosine (Globo H-ßSph) as an acceptor substrate and two glycosyl transferases, an α1,3-N-acetylgalactosaminyltransferase from Helicobacter mustelae (BgtA) and a human blood group B α1,3-galactosyltransferase (h1,3GTB), for stereoselective construction of the terminal α1,3-GalNAc and α1,3-Gal linkages, respectively. The azido-Sph lipid sidechain is further elaborated by reduction and a chemoselective N-acylation to complete the total synthesis of the neutral Globo-series GSLs. In addition, the synthesis of Forssman and para-Forssman antigens were prepared. The strategy may be suitable for accessing other complex GSLs and related lipid-modified GSL derivatives.


Assuntos
Glicoesfingolipídeos , Glicoesfingolipídeos Neutros , Humanos , Glicoesfingolipídeos/metabolismo , Ligação Proteica
6.
Biomed J ; : 100612, 2023 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-37290529

RESUMO

BACKGROUND: Malignant cells may arise from dedifferentiation of mature cells and acquire features of the progenitor cells. Definitive endoderm from which liver is derived, expresses glycosphingolipids such as SSEA3, Globo H, and SSEA4. Herein, we evaluated the potential prognosis value of the three glycosphingolipids and biological functions of SSEA3 in hepatocellular carcinoma (HCC). METHODS: The expression of SSEA3, Globo H, and SSEA4 in tumor tissues obtained from 382 patients with resectable HCC was examined by immunohistochemistry staining. Epithelial mesenchymal transition (EMT) and their related genes were analyzed by transwell assay and qRT-PCR, respectively. RESULTS: Kaplan Meier survival analysis showed significantly shorter relapse-free survival (RFS) for those with higher expression of SSEA3 (P < 0.001), Globo H (P < 0.001), and SSEA4 (P = 0.005) and worse overall survival (OS) for those with high expression of either SSEA3 (P < 0.001) or SSEA4 (P = 0.01). Furthermore, multivariable Cox regression analysis identified the SSEA3 as an independent predictor for RFS (HR: 2.68, 95% CI: 1.93-3.72, P < 0.001) and OS (HR: 2.99, 95% CI: 1.81-4.96, P < 0.001) in HCC. Additionally, SSEA3-ceramide enhanced the EMT of HCC cells, as reflected by its ability to increase migration, invasion and upregulate the expression of CDH2, vimentin, fibronectin, and MMP2, along with ZEB1. Moreover, ZEB1 silencing abrogated the EMT-enhancing effects of SSEA3-ceramide. CONCLUSIONS: Higher expression of SSEA3 was an independent predictor for RFS and OS in HCC and promoted EMT of HCC via upregulation of ZEB1.

7.
Foot Ankle Int ; 44(5): 431-442, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36946569

RESUMO

BACKGROUND: Currently, the standard of treatment for trimalleolar (TM) fracture is osteosynthesis through open reduction and internal fixation (ORIF). This study assessed whether arthroscopically assisted reduction and minimally invasive surgery (AARMIS) can be an alternative surgical method for TM fractures. METHODS: This retrospective cohort study included 49 patients with TM that were surgically treated. 27 patients received ORIF and 22 patients underwent AARMIS . At baseline, we recorded the patient's demographic features, fracture pattern (AO-OTA and Haraguchi classification), and surgical method. For postoperative results, we examined the patient's radiographic outcome, including time to union, quality of fracture reduction, as well as functional outcomes (American Orthopaedic Foot & Ankle Society ankle hindfoot score, ankle range of motion, and visual analog scale of pain) and perioperative complications. RESULTS: At mean follow-up of 46.6±24.6 (ORIF) and 36.4±18.5 months (AARMIS), both groups had comparable radiographic outcomes. No significant difference in rates of early ankle OA were detected. In terms of functional outcome, VAS pain and AOFAS score at postoperative day 3, postoperative month 3, and at final follow-up were not different. In terms of range of motion, we did not find a significant difference in mean range of motion. CONCLUSION: Patients with TM fractures treated with AARMIS achieved satisfactory results and was not significantly different in radiographic and functional performance compared with ORIF. LEVEL OF EVIDENCE: Level III, retrospective cohort study.


Assuntos
Fraturas do Tornozelo , Humanos , Fraturas do Tornozelo/diagnóstico por imagem , Fraturas do Tornozelo/cirurgia , Estudos Retrospectivos , Resultado do Tratamento , Fixação Interna de Fraturas/métodos , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Dor/etiologia
8.
Mayo Clin Proc ; 98(1): 88-99, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36109207

RESUMO

OBJECTIVE: To investigate the effectiveness and safety of angiotensin receptor-neprilysin inhibitors (ARNIs) in real-world patients with heart failure with reduced ejection fraction (HFrEF) and advanced chronic kidney disease (estimated glomerular filtration rate [eGFR] < 30 mL/min per 1.73 m2), which have been excluded from the landmark trials. PATIENTS AND METHODS: This study examined 3281 patients pooled from two multicenter HFrEF cohorts, and 661 patients with baseline eGFR less than 30 mL/min per 1.73 m2 were further analyzed (the Taiwan Society of Cardiology - Heart Failure with reduced Ejection Fraction (TSOC-HFrEF) registry: May 1, 2013 to October 31, 2014, and the Treatment with Angiotensin Receptor neprilysin inhibitor fOr Taiwan Heart Failure patients (TAROT-HF) study: March 1, 2017, to December 31, 2018). Propensity score matching was performed to adjust for confounders. At 1-year follow-up, all-cause mortality, total heart failure hospitalizations, renal function, and left ventricular ejection fraction (LVEF) were used as the endpoints. RESULTS: After propensity score matching, 510 patients (age, 69.8±13.9 years; male, 61.0%; mean LVEF, 29.8±7.3%; mean eGFR, 19.8±9.0 mL/min per 1.73 m2) were included in the final analysis, including 278 patients receiving ARNI treatment (ARNI group) and 232 patients not on ARNI treatment (non-ARNI group). Baseline characteristics were comparable between the two groups. At 1 year, eGFR and LVEF measurements were significantly higher in the ARNI group than in the non-ARNI group (25.0±17.1 mL/min per 1.73 m2 vs 21.4±17.5 mL/min per 1.73 m2; P=.04; and 40.1±12.9% vs. 33.1±10.8%, P<.001, respectively). The ARNI group had significantly lower risks of 1-year all-cause mortality (19.4 vs 30.9 per 100-person year; P=.02), and total HF rehospitalizations (70.0 vs 110.4 per 100-person year; P=.01) than non-ARNI users. CONCLUSION: Our results show the effectiveness of ARNIs in HFrEF patients with advanced chronic kidney disease in a real-world setting.


Assuntos
Insuficiência Cardíaca , Insuficiência Renal Crônica , Idoso , Idoso de 80 Anos ou mais , Humanos , Masculino , Pessoa de Meia-Idade , Antagonistas de Receptores de Angiotensina/uso terapêutico , Angiotensinas , Combinação de Medicamentos , Insuficiência Cardíaca/tratamento farmacológico , Rim/fisiologia , Neprilisina , Receptores de Angiotensina , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/tratamento farmacológico , Volume Sistólico/fisiologia , Resultado do Tratamento , Valsartana , Função Ventricular Esquerda , Feminino
9.
Materials (Basel) ; 15(24)2022 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-36556708

RESUMO

Perovskite CsPbI3 quantum dots (QDs) were synthesized as a hole-transporting layer (HTL) of a planar perovskite solar cell (PSC). By using the Octam solution during the ligand engineering, CsPbI3 QDs exhibits a denser grain and a larger grain size due to the short-chain ligands of Octam. In addition, CsPbI3 QDs with the Octam solution showed a smooth and uniform surface on MAPbI3 film, indicating the QDs improved the microstructure of the MAPbI3 perovskite film. As a result, the PSC with CsPbI3 QDs as an HTL has the optimal open-circuit voltage as 1.09 V, the short-circuit current as 20.5 mA/cm2, and the fill factor (FF) as 75.7%, and the power conversion efficiency (PCE) as 17.0%. Hence, it is inferred that introducing QDs as a HTL via the ligand engineering can effectively improve the device performance of the PSC.

10.
J Biomed Sci ; 29(1): 105, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36517806

RESUMO

BACKGROUND: In endothelial cells, phospholipase C (PLC) ß1-activated Ca2+ is a crucial second messenger for the signaling pathways governing angiogenesis. PLCß1 is inactivated by complexing with an intracellular protein called translin-associated factor X (TRAX). This study demonstrates specific interactions between Globo H ceramide (GHCer) and TRAX, which highlight a new angiogenic control through PLCß1 activation. METHODS: Globo-series glycosphingolipids (GSLs), including GHCer and stage-specific embryonic antigen-3 ceramide (SSEA3Cer), were analyzed using enzyme-linked immunosorbent assay (ELISA) and Biacore for their binding with TRAX. Angiogenic activities of GSLs in human umbilical vein endothelial cells (HUVECs) were evaluated. Molecular dynamics (MD) simulation was used to study conformations of GSLs and their molecular interactions with TRAX. Fluorescence resonance energy transfer (FRET) analysis of HUVECs by confocal microscopy was used to validate the release of PLCß1 from TRAX. Furthermore, the in vivo angiogenic activity of extracellular vesicles (EVs) containing GHCer was confirmed using subcutaneous Matrigel plug assay in mice. RESULTS: The results of ELISA and Biacore analysis showed a stable complex between recombinant TRAX and synthetic GHCer with KD of 40.9 nM. In contrast, SSEA3Cer lacking a fucose residue of GHCer at the terminal showed ~ 1000-fold decrease in the binding affinity. These results were consistent with their angiogenic activities in HUVECs. The MD simulation indicated that TRAX interacted with the glycan moiety of GHCer at amino acid Q223, Q219, L142, S141, and E216. At equilibrium the stable complex maintained 4.6 ± 1.3 H-bonds. TRAX containing double mutations with Q223A and Q219A lost its ability to interact with GHCer in both MD simulation and Biacore assays. Removal of the terminal fucose from GHCer to become SSEA3Cer resulted in decreased H-bonding to 1.2 ± 1.0 by the MD simulation. Such specific H-bonding was due to the conformational alteration in the whole glycan which was affected by the presence or absence of the fucose moiety. In addition, ELISA, Biacore, and in-cell FRET assays confirmed the competition between GHCer and PLCß1 for binding to TRAX. Furthermore, the Matrigel plug assay showed robust vessel formation in the plug containing tumor-secreted EVs or synthetic GHCer, but not in the plug with SSEA3Cer. The FRET analysis also indicated the disruption of colocalization of TRAX and PLCß1 in cells by GHCer derived from EVs. CONCLUSIONS: Overall, the fucose residue in GHCer dictated the glycan conformation for its complexing with TRAX to release TRAX-sequestered PLCß1, leading to Ca2+ mobilization in endothelial cells and enhancing angiogenesis in tumor microenvironments.


Assuntos
Proteínas de Ligação a DNA , Fucose , Células Endoteliais da Veia Umbilical Humana , Animais , Humanos , Camundongos , Ceramidas , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Fucose/genética , Fucose/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Fosfolipase C beta/genética , Fosfolipase C beta/metabolismo
11.
Nanomaterials (Basel) ; 12(22)2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-36432243

RESUMO

In this study, blue perovskite quantum dots (PQDs) were prepared using didodecyldimethylammonium bromide (DDAB), which can passivate surface defects caused by the loss of surface ligands and reduce particle size distribution. After the passivation of DDAB, blue CsPbClxBr3-x PQDs dispersed in n-octane produced a more compact and uniform PQD thin film than the non-passivated ones. The resulting device showed a stabile lifetime, and an EL peak of 470 nm and a maximum EQE of 1.63% were obtained at an operating voltage of 2.6 V and a current density of 0.34 mA/cm2. This work aims to provide a simple method to prepare blue-emitting PQDs and high-performance PQD-based light-emitting devices.

12.
Int J Mol Sci ; 23(21)2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36362187

RESUMO

Structural variants of α-galactosylceramide (α-GalCer) that stimulate invariant natural killer T (iNKT) cells constitute an emerging class of immunomodulatory agents in development for numerous biological applications. Variations in lipid chain length and/or fatty acids in these glycoceramides selectively trigger specific pro-inflammatory responses. Studies that would link a specific function to a structurally distinct α-GalCer rely heavily on the availability of homogeneous and pure materials. To address this need, we report herein a general route to the diversification of the ceramide portion of α-GalCer glycolipids. Our convergent synthesis commences from common building blocks and relies on the Julia-Kocienski olefination as a key step. A cleavable fluorous tag is introduced at the non-reducing end of the sugar that facilitates quick purification of products by standard fluorous solid-phase extraction. The strategy enabled the rapid generation of a focused library of 61 α-GalCer analogs by efficiently assembling various lipids and fatty acids. Furthermore, when compared against parent α-GalCer in murine cells, many of these glycolipid variants were found to have iNKT cell stimulating activity similar to or greater than KRN7000. ELISA assaying indicated that glycolipids carrying short fatty N-acyl chains (1fc and 1ga), an unsubstituted (1fh and 1fi) or CF3-substituted phenyl ring at the lipid tail, and a flexible, shorter fatty acyl chain with an aromatic ring (1ge, 1gf, and 1gg) strongly affected the activation of iNKT cells by the glycolipid-loaded antigen-presenting molecule, CD1d. This indicates that the method may benefit the design of structural modifications to potent iNKT cell-binding glycolipids.


Assuntos
Interleucina-2 , Células T Matadoras Naturais , Camundongos , Animais , Antígenos CD1d , Glicolipídeos/farmacologia , Ácidos Graxos
13.
RSC Adv ; 12(29): 18985-18993, 2022 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-35873332

RESUMO

Sialyl-Tn (STn), overexpressed on various tumors, has been investigated for its application in anti-cancer vaccine therapy. However, Theratope, an STn-based vaccine, failed in the phase III clinical trial due to poor immunogenicity and epitope suppression by the foreign carrier protein. We therefore developed a self-adjuvanting STn based-vaccine, a conjugate of clustered STn (triSTn) antigen, TLR1/2 ligand (Pam3CSK4), and T-helper (Th) cell epitope, and found that this three-component self-adjuvanting vaccine effectively resulted in the production of anti-triSTn IgG antibodies. We herein analyzed immune responses induced by this self-adjuvanting vaccine in detail. We newly synthesized two-component vaccines, i.e., Pam3CSK4- or Th epitope-conjugated triSTn, as references to evaluate the immune-stimulating functions of Pam3CSK4 and Th epitope. Immunological evaluation of the synthesized vaccine candidates revealed that Pam3CSK4 was essential for antibody production, indicating that the uptake of triSTn antigen by antigen-presenting cells (APCs) was promoted by the recognition of Pam3CSK4 by TLR1/2. The function of the Th epitope was also confirmed. Th cell activation was important for boosting antibody production and IgG subclass switching. Furthermore, flow cytometric analyses of immune cells, including T cells, B cells, dendritic cells, and other monocytes, were first employed in the evaluation of self-adjuvanting vaccines and revealed that the three-component vaccine was able to induce antigen-specific immune responses for efficient antibody production without excessive inflammatory responses. Importantly, the co-administration of Freund's adjuvants was suggested to cause excessive myeloid cell accumulation and decreased plasma cell differentiation. These results demonstrate that vaccines can be designed to achieve the desired immune responses via the bottom-up construction of each immune element.

14.
Int J Mol Sci ; 23(14)2022 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-35886992

RESUMO

Chikungunya virus (CHIKV) has repeatedly spread via the bite of an infected mosquito and affected more than 100 countries. The disease poses threats to public health and the economy in the infected locations. Many efforts have been devoted to identifying compounds that could inhibit CHIKV. Unfortunately, successful clinical candidates have not been found yet. Computations through the simulating recognition process were performed on complexation of the nsP3 protein of CHIKV with the structures of triply conjugated drug lead candidates. The outcomes provided the aid on rational design of functionalized quinazoline-(α-substituted coumarin)-arylsulfonate compounds to inhibit CHIKV in Vero cells. The molecular docking studies showed a void space around the ß carbon atom of coumarin when a substituent was attached at the α position. The formed vacancy offered a good chance for a Michael addition to take place owing to steric and electronic effects. The best conjugate containing a quinazolinone moiety exhibited potency with EC50 = 6.46 µM, low toxicity with CC50 = 59.7 µM, and the selective index (SI) = 9.24. Furthermore, the corresponding 4-anilinoquinazoline derivative improved the anti-CHIKV potency to EC50 = 3.84 µM, CC50 = 72.3 µM, and SI = 18.8. The conjugate with 4-anilinoquinazoline exhibited stronger binding affinity towards the macro domain than that with quinazolinone via hydrophobic and hydrogen bond interactions.


Assuntos
Vírus Chikungunya , Animais , Antivirais/química , Sulfonatos de Arila/metabolismo , Sulfonatos de Arila/farmacologia , Chlorocebus aethiops , Desenho Assistido por Computador , Cumarínicos/farmacologia , Simulação de Acoplamento Molecular , Quinazolinas/metabolismo , Quinazolinas/farmacologia , Quinazolinonas/farmacologia , Células Vero , Replicação Viral
15.
Bioorg Med Chem ; 67: 116839, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35640379

RESUMO

Naturally occurring N-glycans display much diversity in modifications, linkages, and peripheral presentation of the oligosaccharide chain. Despite continued advancements in oligosaccharide synthesis, synthetic access to these natural glycans remains challenging. Biologically relevant complex N-glycan mimetics with various natural and unnatural modifications are an alternate way for investigating glycan-protein interactions. Further supporting this pattern, we report here a new class of sialylated bi- and triantennary pseudo mannose N-glycans reproducing orientation of the underlying glycan chain and branching patterns and replacing the two inner mannopyranosyl units with 1,2,3-triazole rings. Such mimetics are straightforwardly generated by implementing multiple intermolecular Cu(I)-catalyzed azide-alkyne cycloaddition between chemoenzymatically synthesized azido sialosides and rationally designed C-3 and C-6 di-O- or C-2, C-3, and C-6 tri-O-alkynylated mannoside. Human recombinant Siglec-7-Fc fusion protein recognizes almost all sialylated pseudo mannose N-glycans in the microarray. However, a differential Sia-binding pattern was also observed. Given the library size, comparison of pairwise mannose N-glycan combinations showed that biantennary linear α(2,3)α(2,8)- and α(2,6)α(2,8)- or branched α(2,3)α(2,6)-, and triantennary branched α(2,3)α(2,6)-sialyl pseudo N-glycans possess similar binding capabilities and affinity to recombinant Siglec-7-Fc. While the full range of topological mannose arms remain elusive, the bi- and triantennary mimics are simpler structures for interrogating Siglec interactions.


Assuntos
Manose , Polissacarídeos , Humanos , Manose/química , Oligossacarídeos/química , Polissacarídeos/química , Lectinas Semelhantes a Imunoglobulina de Ligação ao Ácido Siálico/metabolismo
16.
Chem Asian J ; 17(16): e202200403, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35616406

RESUMO

Glycosphingolipids (GSLs) play essential roles in many important biological processes, making them attractive synthetic targets. In this paper, a viable chemoenzymatic method is described for the synthesis of globo-series GSLs, namely, Gb4, Gb5, SSEA-4, and Globo H. The strategy uses a chemically synthesized lactoside acceptor equipped with a partial ceramide structure that is uniquely extended by glycosyltransferases in a highly efficient one-pot multiple enzyme (OPME) procedure. A direct and quantitative conversion of Gb4 sphingosine to Globo H sphingosine is achieved by performing two-sequential OPME glycosylations. A reduction and N-acylation protocol allows facile incorporation of various fatty acids into the lipid portions of the GSLs. The chemically well-defined lipid-modified Globo H-GSLs displayed some differences in their immunosuppressive activities, which may benefit the structural modifications of Globo H ceramides in finding new types of immunosuppressive agents. The strategy outlined in this work should be applicable to the rapid access to other complex GSLs.


Assuntos
Glicoesfingolipídeos , Esfingosina , Glicoesfingolipídeos/química , Glicoesfingolipídeos/metabolismo , Imunossupressores/farmacologia
19.
J Pers Med ; 12(2)2022 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-35207798

RESUMO

Patients who undergo splenectomy are at a high risk of infection. We aimed to investigate the rate of pneumonia in patients who underwent splenectomy, specifically comparing those who had splenectomy due to spleen injury and those who had it for other reasons. A population-based cohort study was conducted. Overall, 17,498 patients who underwent splenectomy between 2000 and 2015 were enrolled, including 11,817 patients with a history of spleen injury and 5681 controls without spleen injury. The incidence of pneumonia was calculated at the end of 2016. A multivariable Cox proportional hazards regression model was used to compare the hazard ratio with 95% CI for pneumonia associated with the spleen injury-caused splenectomy and splenectomy due to other causes. The crude HR for patients with splenectomy due to spleen injury to develop pneumonia was 1.649. After adjusting for covariates, the adjusted hazard ratio was 1.567. There were statistically significant differences in all subgroups, except for the group with a tracking duration >10 years. We found an increase in pneumonia risk in the 'spleen injury' group when comparing it to that of the 'other causes' group, regardless of age, sex, and area of residence.

20.
Chemistry ; 28(17): e202104178, 2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35143090

RESUMO

The excellent molecular recognition capabilities of monoclonal antibodies (mAbs) have opened up exciting opportunities for biotherapeutic discovery. Taking advantage of the full potential of this tool necessitates affinity ligands capable of conjugating directly with small molecules to a defined degree of biorthogonality, especially when modifying natural Abs. Herein, a bioorthogonal boronate-affinity-based Ab ligand featuring a 4-(dimethylamino)pyridine and an S-aryl thioester to label full-length Abs is reported. The photoactivatable linker in the acyl donor facilitated purification of azide-labelled Ab (N3 -Ab) was quantitatively cleaved upon brief exposure to UV light while retaining the original Ab activity. Click reactions enabled the precise addition of biotin, a fluorophore, and a pharmacological agent to the purified N3 -Abs. The resulting immunoconjugate showed selectivity against targeted cells. Bioorthogonal traceless design and reagentless purification allow this strategy to be a powerful tool to engineer native antibodies amenable to therapeutic intervention.


Assuntos
Imunoconjugados , Acilação , Anticorpos Monoclonais , Azidas , Corantes Fluorescentes
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