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1.
Sci Total Environ ; 907: 167925, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-37863215

RESUMO

Subtropical ecosystems are strongly affected by nitrogen (N) deposition, impacting soil organic matter (SOM) availability and stocks. Here we aimed to reveal the effects of N deposition on i) the structure and functioning of microbial communities and ii) the temperature sensitivity (Q10) of SOM decomposition. Phosphorus (P) limited evergreen forest in Guangdong Province, southeastern China, was selected, and N deposition (factor level: N (100 kg N ha-1 y-1 (NH4NO3)) and control (water), arranged into randomized complete block design (n = 3)) was performed during 2.5 y. After that soils from 0 to 20 cm were collected, analyzed for the set of parameters and incubated at 15, and 25, and 35 °C for 112 days. N deposition increased the microbial biomass N and the content of fungal and Gram-positive bacterial biomarkers; activities of beta-glucosidase (BG) and acid phosphatase (ACP) also increased showing the intensification of SOM decomposition. The Q10 of SOM decomposition under N deposition was 1.66 and increased by 1.4 times than under control. Xylosidase (BX), BG, and ACP activities increased with temperature under N but decreased with the incubation duration, indicating either low production and/or decomposition of enzymes. Activities of polyphenol-(PPO) and peroxidases (POD) were higher under N than in the control soil and were constant during the incubation showing the intensification of recalcitrant SOM decomposition. At the early incubation stage (10 days), the increase of Q10 of CO2 efflux was explained by the activities of BX, BQ, ACP, and POD and the quality of the available dissolved organic matter pool. At the later incubation stages (112 days), the drop of Q10 of CO2 efflux was due to the depletion of the labile organic substances and the shift of microbial community structure to K-strategists. Thus, N deposition decoupled the effects of extracellular enzyme activities from microbial community structure on Q10 of SOM decomposition in the subtropical forest soil.


Assuntos
Ecossistema , Solo , Carbono , Dióxido de Carbono , Florestas , Nitrogênio , Solo/química , Microbiologia do Solo , Temperatura
2.
J Agric Food Chem ; 71(48): 18674-18684, 2023 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-37982580

RESUMO

Branched-long-chain monomethyl fatty acids (BLCFA) are consumed daily in significant amounts by humans in all stages of life. BLCFA are absorbed and metabolized in human intestinal epithelial cells and are not only oxidized for energy. Thus far, BLCFA have been revealed to possess versatile beneficial bioactivities, including cytotoxicity to cancer cells, anti-inflammation, lipid-lowering, reducing the risk of metabolic disorders, maintaining normal ß cell function and insulin sensitivity, regulation of development, and mitigating cerebral ischemia/reperfusion injury. However, compared to other well-studied dietary fatty acids like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), BLCFA has received disproportionate attention despite their potential importance. Here we outlined the major food sources, estimated intake, absorption, and metabolism in human cells, and bioactive properties of BLCFA with a focus on the bioactive mechanisms to advocate for an increased commitment to BLCFA investigations. Humans were estimated to absorb 6-5000 mg of dietary BLCFA daily from fetus to adult. Notably, iso-15:0 inhibited the growth of prostate cancer, liver cancer and T-cell non-Hodgkin lymphomas in rodent models at the effective doses of 35-105 mg/kg/day, 70 mg/kg/day, and 70 mg/kg/day, respectively. Feeding formula prepared with 20% w/w BLCFA mixture to neonatal rats with enterocolitis mitigated the intestine inflammation. Iso-15:0 at doses of 10, 40, and 80 mg/kg relieved brain ischemia/reperfusion injury in rats. In the future, it is crucial to conduct research to establish the epidemiology of BLCFA intake and their impacts on health outcomes in humans as well as to fully uncover the underlying mechanisms for their bioactivities.


Assuntos
Ácidos Graxos Ômega-3 , Traumatismo por Reperfusão , Masculino , Adulto , Humanos , Ratos , Animais , Ácidos Graxos/metabolismo , Ácido Eicosapentaenoico , Ácidos Docosa-Hexaenoicos/metabolismo , Dieta
4.
In Vitro Cell Dev Biol Anim ; 59(4): 264-276, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37173557

RESUMO

Resveratrol (Res) is a bioactive dietary component and alleviates apoptosis in multiple cell types. However, its effect and mechanism on lipopolysaccharide (LPS)-induced bovine mammary epithelial cells (BMEC) apoptosis, which commonly happens in dairy cows with mastitis, is unknown. We hypothesized that Res would inhibit LPS-induced apoptosis in BMEC through SIRT3, a NAD + -dependent deacetylase activated by Res. To test the dose-response effect on apoptosis, 0-50 µM Res were incubated with BMEC for 12 h, followed by 250 µg/mL LPS treatment for 12 h. To investigate the role of SIRT3 in Res-mediated alleviation of apoptosis, BMEC were pretreated with 50 µM Res for 12 h, then incubated with si-SIRT3 for 12 h and were finally treated with 250 µg/mL LPS for 12 h. Res dose-dependently promoted the cell viability and protein levels of Bcl-2 (Linear P < 0.001) but decreased protein levels of Bax, Caspase-3 and Bax/Bcl-2 (Linear P < 0.001). TUNEL assays indicated that cellular fluorescence intensity declined with the rising doses of Res. Res also dose-dependently upregulated SIRT3 expression, but LPS had the opposite effect. SIRT3 silencing abolished these results with Res incubation. Mechanically, Res enhanced the nuclear translocation of PGC1α, the transcriptional cofactor for SIRT3. Further molecular docking analysis revealed that Res could directly bind to PGC1α by forming a hydrogen bond with Tyr-722. Overall, our data suggested that Res relieved LPS-induced BMEC apoptosis through the PGC1α-SIRT3 axis, providing a basis for further in vivo investigations of applying Res to relieve mastitis in dairy cows.


Assuntos
Doenças dos Bovinos , Mastite , Sirtuína 3 , Feminino , Bovinos , Animais , Resveratrol/farmacologia , Resveratrol/metabolismo , Lipopolissacarídeos/toxicidade , Sirtuína 3/genética , Sirtuína 3/metabolismo , Sirtuína 3/farmacologia , Simulação de Acoplamento Molecular , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Proteína X Associada a bcl-2/metabolismo , Glândulas Mamárias Animais/metabolismo , Células Epiteliais/metabolismo , Mastite/metabolismo , Apoptose
5.
Front Nutr ; 9: 1066074, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36466399

RESUMO

This study was conducted to evaluate the influences of supplementing tannic acid (TA) at different doses on the production performance, physiological and immunological characteristics, and rumen bacterial microbiome of cattle. Forty-eight Holstein bulls were randomly allocated to four dietary treatments: the control (CON, basal diet), the low-dose TA treatment [TAL, 0.3% dry matter (DM)], the mid-dose TA treatment (TAM, 0.9% DM), and the high-dose TA treatment (TAH, 2.7% DM). This trial consisted of 7 days for adaptation and 90 days for data and sample collection, and samples of blood and rumen fluid were collected on 37, 67, and 97 d, respectively. The average daily gain was unaffected (P > 0.05), whilst the ruminal NH3-N was significantly decreased (P < 0.01) by TA supplementation. The 0.3% TA addition lowered (P < 0.05) the levels of ruminal isobutyrate, valerate, and tumor necrosis factor alpha (TNF-α), and tended to (P < 0.1) increase the gain to feed ratio. The digestibility of DM, organic matter (OM), and crude protein, and percentages of butyrate, isobutyrate, and valerate were lower (P < 0.05), while the acetate proportion and acetate to propionate ratio in both TAM and TAH were higher (P < 0.05) than the CON. Besides, the 0.9% TA inclusion lessened (P < 0.05) the concentrations of glucagon and TNF-α, but enhanced (P < 0.05) the interferon gamma (IFN-γ) level and Simpson index of ruminal bacteria. The 2.7% TA supplementation reduced (P < 0.05) the intake of DM and OM, and levels of malondialdehyde and thyroxine, while elevated (P < 0.05) the Shannon index of the rumen bacterial populations. Moreover, the relative abundances of the phyla Fibrobacteres and Lentisphaerae, the genera Fibrobacter and Bradyrhizobium, and the species Bradyrhizobium sp., Lachnospiraceae bacterium RM29, and Lachnospiraceae bacterium CG57 were highly significantly (q < 0.01) or significantly (q < 0.05) raised by adding 2.7% TA. Results suggested that the TA addition at 0.3% is more suitable for the cattle, based on the general comparison on the impacts of supplementing TA at different doses on all the measured parameters.

6.
Front Vet Sci ; 9: 812373, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35647087

RESUMO

This experiment was performed to reveal the metabolic responses of dairy cows to the replacement of soybean meal (SBM) with fermented soybean meal (FSBM). Twenty-four lactating Chinese Holstein dairy cattle were assigned to either the SBM group [the basal total mixed ration (TMR) diet containing 5.77% SBM] or the FSBM group (the experimental TMR diet containing 5.55% FSBM), in a completely randomized design. The entire period of this trial consisted of 14 days for the adjustment and 40 days for data and sample collection, and sampling for rumen liquid, blood, milk, and urine was conducted on the 34th and 54th day, respectively. When SBM was completely replaced by FSBM, the levels of several medium-chain FA in milk (i.e., C13:0, C14:1, and C16:0) rose significantly (p < 0.05), while the concentrations of a few milk long-chain FA (i.e., C17:0, C18:0, C18:1n9c, and C20:0) declined significantly (p < 0.05). Besides, the densities of urea nitrogen and lactic acid were significantly (p < 0.05) higher, while the glucose concentration was significantly (p < 0.05) lower in the blood of the FSBM-fed cows than in the SBM-fed cows. Based on the metabolomics analysis simultaneously targeting the rumen liquid, plasma, milk, and urine, it was noticed that substituting FSBM for SBM altered the metabolic profiles of all the four biofluids. According to the identified significantly different metabolites, 3 and 2 amino acid-relevant metabolic pathways were identified as the significantly different pathways between the two treatments in the rumen fluid and urine, respectively. Furthermore, glycine, serine, and threonine metabolism, valine, leucine, and isoleucine biosynthesis, and cysteine and methionine metabolism were the three key integrated different pathways identified in this study. Results mainly implied that the FSBM replacement could enhance nitrogen utilization and possibly influence the inflammatory reactions and antioxidative functions of dairy cattle. The differential metabolites and relevant pathways discovered in this experiment could serve as biomarkers for the alterations in protein feed and nitrogen utilization efficiency of dairy cows, and further investigations are needed to elucidate the definite roles and correlations of the differential metabolites and pathways.

7.
ACS Chem Biol ; 17(5): 1249-1258, 2022 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-35417146

RESUMO

Recent clinical trials have revealed that the chimeric peptide hormones simultaneously activating glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) demonstrate superior efficacy in glycemic control and body weight reduction, better than those activating the GLP-1R alone. However, the linear peptide-based GLP-1R/GIPR dual agonists are susceptible to proteolytic cleavage by common digestive enzymes present in the gastrointestinal tract and thus not suitable for oral administration. Here, we report the design and synthesis of biaryl-stapled peptides, with and without fatty diacid attachment, that showed potent GLP-1R/GIPR dual agonist activities. Compared to a linear peptide dual agonist and semaglutide, the biaryl-stapled peptides displayed drastically improved proteolytic stability against the common digestive enzymes. Furthermore, two stapled peptides showed excellent efficacy in an oral glucose tolerance test in mice, owing to their potent receptor activity in vitro and good pharmacokinetics exposure upon subcutaneous injection. By exploring a more comprehensive set of biaryl staplers, we expect that this stapling method could facilitate the design of the stapled peptide-based dual agonists suitable for oral administration.


Assuntos
Receptores dos Hormônios Gastrointestinais , Animais , Polipeptídeo Inibidor Gástrico , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Camundongos , Peptídeos/farmacologia , Receptores Acoplados a Proteínas G , Receptores dos Hormônios Gastrointestinais/agonistas
8.
Inflammation ; 45(1): 331-342, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34478012

RESUMO

Sepsis-induced lung injury is a clinical syndrome characterized by injury of alveolar epithelium cells (AECs). Previous investigations illustrate that exosomes secreted from adipose-derived stem cells (ADSCs) have therapeutic effects in a variety of disease treatments, but roles and mechanisms regarding ADSC-derived exosomes in sepsis-induced lung injury are unclear. In this study, high-throughput sequencing was used to explore the molecular delivery of ADSC exosomes. A sepsis-induced lung injury mouse model and a lipopolysaccharide-induced AEC damage model were used for mechanistic analysis. The results showed that ADSC exosomes have high levels of the circular RNA (circ)-Fryl. Downregulation of circ-Fryl suppressed ADSC protective effects exosomes against sepsis-induced lung injury by decreasing apoptosis and inflammatory factor expression. Bioinformatics and luciferase reporting experiments showed that miR-490-3p and SIRT3 are downstream targets of circ-Fryl. miR-490-3p overexpression or SIRT3 silencing reversed ADSC exosome protective effects. Studying the mechanism showed that overexpression of circ-Fryl promoted autophagy activation by inducing SIRT3/AMPK signaling. Autophagy activation can suppress sepsis-induced lung injury by decreasing apoptosis and inflammatory factor expression. Taken together, our results suggest that exosomes derived from ADSCs attenuate sepsis-induced lung injury by delivery of circ-Fryl and regulation of the miR-490-3p/SIRT3 pathway.


Assuntos
Exossomos/metabolismo , Lesão Pulmonar/metabolismo , Células-Tronco Mesenquimais/metabolismo , MicroRNAs/metabolismo , RNA Circular/metabolismo , Sepse/fisiopatologia , Sirtuína 3/metabolismo , Animais , Regulação para Baixo , Lesão Pulmonar/etiologia , Lesão Pulmonar/prevenção & controle , Camundongos , Sepse/metabolismo , Regulação para Cima
9.
Acta Pharm Sin B ; 11(12): 3983-3993, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35024320

RESUMO

Unfolded protein response (UPR) is a stress response that is specific to the endoplasmic reticulum (ER). UPR is activated upon accumulation of unfolded (or misfolded) proteins in the ER's lumen to restore protein folding capacity by increasing the synthesis of chaperones. In addition, UPR also enhances degradation of unfolded proteins and reduces global protein synthesis to alleviate additional accumulation of unfolded proteins in the ER. Herein, we describe a cell-based ultra-high throughput screening (uHTS) campaign that identifies a small molecule that can modulate UPR and ER stress in cellular and in vivo disease models. Using asialoglycoprotein receptor 1 (ASGR) fused with Cypridina luciferase (CLuc) as reporter assay for folding capacity, we have screened a million small molecule library and identified APC655 as a potent activator of protein folding, that appears to act by promoting chaperone expression. Furthermore, APC655 improved pancreatic ß cell viability and insulin secretion under ER stress conditions induced by thapsigargin or cytokines. APC655 was also effective in preserving ß cell function and decreasing lipid accumulation in the liver of the leptin-deficient (ob/ob) mouse model. These results demonstrate a successful uHTS campaign that identified a modulator of UPR, which can provide a novel candidate for potential therapeutic development for a host of metabolic diseases.

10.
J Med Chem ; 63(17): 9660-9671, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32844654

RESUMO

Bariatric surgery results in increased intestinal secretion of hormones GLP-1 and anorexigenic PYY, which is believed to contribute to the clinical efficacy associated with the procedure. This observation raises the question whether combination treatment with gut hormone analogs might recapitulate the efficacy and mitigate the significant risks associated with surgery. Despite PYY demonstrating excellent efficacy and safety profiles with regard to food intake reduction, weight loss, and glucose control in preclinical animal models, PYY-based therapeutic development remains challenging given a low serum stability and half-life for the native peptide. Here, combined peptide stapling and PEG-fatty acid conjugation affords potent PYY analogs with >14 h rat half-lives, which are expected to translate into a human half-life suitable for once-weekly dosing. Excellent efficacy in glucose control, food intake reduction, and weight loss for lead candidate 22 in combination with our previously reported long-acting GLP-1 analog is demonstrated in a diet-induced obesity mouse model.


Assuntos
Engenharia , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Obesidade/tratamento farmacológico , Peptídeo YY/química , Peptídeo YY/farmacologia , Receptores de Neuropeptídeo Y/agonistas , Sequência de Aminoácidos , Animais , Peso Corporal/efeitos dos fármacos , Interações Medicamentosas , Ingestão de Alimentos/efeitos dos fármacos , Meia-Vida , Modelos Moleculares , Peptídeo YY/farmacocinética , Polietilenoglicóis/química , Conformação Proteica , Ratos
11.
Neurotherapeutics ; 17(4): 1861-1877, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32638217

RESUMO

Loss of dopaminergic neurons along the nigrostriatal axis, neuroinflammation, and peripheral immune dysfunction are the pathobiological hallmarks of Parkinson's disease (PD). Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been successfully tested for PD treatment. GM-CSF is a known immune modulator that induces regulatory T cells (Tregs) and serves as a neuronal protectant in a broad range of neurodegenerative diseases. Due to its short half-life, limited biodistribution, and potential adverse effects, alternative long-acting treatment schemes are of immediate need. A long-acting mouse GM-CSF (mPDM608) was developed through Calibr, a Division of Scripps Research. Following mPDM608 treatment, complete hematologic and chemistry profiles and T-cell phenotypes and functions were determined. Neuroprotective and anti-inflammatory capacities of mPDM608 were assessed in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice that included transcriptomic immune profiles. Treatment with a single dose of mPDM608 resulted in dose-dependent spleen and white blood cell increases with parallel enhancements in Treg numbers and immunosuppressive function. A shift in CD4+ T-cell gene expression towards an anti-inflammatory phenotype corresponded with decreased microgliosis and increased dopaminergic neuronal cell survival. mPDM608 elicited a neuroprotective peripheral immune transformation. The observed phenotypic shift and neuroprotective response was greater than observed with recombinant GM-CSF (rGM-CSF) suggesting human PDM608 as a candidate for PD treatment.


Assuntos
1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/administração & dosagem , Fator Estimulador de Colônias de Granulócitos e Macrófagos/administração & dosagem , Intoxicação por MPTP/induzido quimicamente , Intoxicação por MPTP/prevenção & controle , Neuroproteção/efeitos dos fármacos , Neurotoxinas/toxicidade , Animais , Relação Dose-Resposta a Droga , Intoxicação por MPTP/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neuroproteção/fisiologia , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia
12.
Molecules ; 25(11)2020 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-32481528

RESUMO

Owing to their pleiotropic metabolic benefits, glucagon-like peptide-1 receptor (GLP-1R) agonists have been successfully utilized for treating metabolic diseases, such as type 2 diabetes and obesity. As part of our efforts in developing long-acting peptide therapeutics, we have previously reported a peptide engineering strategy that combines peptide side chain stapling with covalent integration of a serum protein-binding motif in a single step. Herein, we have used this strategy to develop a second generation extendin-4 analog rigidified with a symmetrical staple, which exhibits an excellent in vivo efficacy in an animal model of diabetes and obesity. To simplify the scale-up manufacturing of the lead GLP-1R agonist, a semisynthesis protocol was successfully developed, which involves recombinant expression of the linear peptide followed by attachment of a polyethylene glycol (PEG)-fatty acid staple in a subsequent chemical reaction step.


Assuntos
Exenatida/análogos & derivados , Exenatida/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Animais , Diabetes Mellitus Tipo 2 , Exenatida/química , Ácidos Graxos/química , Masculino , Camundongos , Estrutura Molecular , Obesidade , Peptídeos/química , Peptídeos/metabolismo , Polietilenoglicóis/química
13.
Sci Adv ; 6(20): eaaz4988, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32440547

RESUMO

Existing long α-helix mimicking necessitates the retention of most natural amino acid residues to maintain their biological activity. Here, we report the exploration of helical sulfono-γ-AApeptides with entire unnatural backbones for their ability to structurally and functionally mimic glucagon-like peptide 1 (GLP-1). Our findings suggest that efficient construction of novel GLP-1 receptor (GLP-1R) agonists could be achieved with nanomolar potencies. In addition, the resulting sulfono-γ-AApeptides were also proved to display remarkable stability against enzymatic degradation compared to GLP-1, augmenting their biological potential. This alternative strategy of α-helix mimicking, as a proof of concept, could provide a new paradigm to prepare GLP-1R agonists.


Assuntos
Peptídeo 1 Semelhante ao Glucagon , Peptidomiméticos , Peptídeos/química , Peptidomiméticos/química , Conformação Proteica em alfa-Hélice
14.
Nat Commun ; 10(1): 5015, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31676778

RESUMO

The loss of functional insulin-producing ß-cells is a hallmark of diabetes. Mammalian sterile 20-like kinase 1 (MST1) is a key regulator of pancreatic ß-cell death and dysfunction; its deficiency restores functional ß-cells and normoglycemia. The identification of MST1 inhibitors represents a promising approach for a ß-cell-protective diabetes therapy. Here, we identify neratinib, an FDA-approved drug targeting HER2/EGFR dual kinases, as a potent MST1 inhibitor, which improves ß-cell survival under multiple diabetogenic conditions in human islets and INS-1E cells. In a pre-clinical study, neratinib attenuates hyperglycemia and improves ß-cell function, survival and ß-cell mass in type 1 (streptozotocin) and type 2 (obese Leprdb/db) diabetic mouse models. In summary, neratinib is a previously unrecognized inhibitor of MST1 and represents a potential ß-cell-protective drug with proof-of-concept in vitro in human islets and in vivo in rodent models of both type 1 and type 2 diabetes.


Assuntos
Diabetes Mellitus Experimental/fisiopatologia , Diabetes Mellitus Tipo 2/fisiopatologia , Células Secretoras de Insulina/efeitos dos fármacos , Quinolinas/farmacologia , Animais , Linhagem Celular Tumoral , Células Cultivadas , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Obesos , Substâncias Protetoras/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Ratos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética
15.
J Biol Chem ; 294(41): 15176-15181, 2019 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-31481465

RESUMO

Skeletal muscle myosin has potent procoagulant activity that is based on its ability to enhance thrombin generation due to binding coagulation factors Xa and Va and accelerating prothrombin activation. A well-studied myosin inhibitor that binds to myosin's neck region inhibits myosin-dependent prothrombin activation. Hence, to identify a potential binding site(s) on skeletal muscle myosin for factor Xa, 19 peptides (25-40 residues) representing the neck region, which consists of a regulatory light chain, an essential light chain, and a heavy chain (HC), were screened for inhibition of myosin-supported prothrombin activation. Peptide HC796-835 comprising residues 796-835 of the heavy chain strongly inhibited myosin-enhanced prothrombin activation by factors Xa and Va (50% inhibition at 1.2 µm), but it did not inhibit phospholipid vesicle-enhanced prothrombin activation. Peptide inhibition studies also implicated several myosin light chain sequences located near HC796-835 as potential procoagulant sites. A peptide comprising HC796-835's C-terminal half, but not a peptide comprising its N-terminal half, inhibited myosin-enhanced prothrombin activation (50% inhibition at 1.2 µm). This inhibitory peptide (HC816-837) did not inhibit phospholipid-enhanced prothrombin activation, indicating its specificity for inhibition of myosin-dependent procoagulant mechanisms. Binding studies showed that purified factor Xa was bound to immobilized peptides HC796-835 and HC816-837 with apparent Kd values of 0.78 and 1.3 µm, respectively. In summary, these studies imply that HC residues 816-835 in the neck region of the skeletal muscle myosin directly bind factor Xa and, with contributions from light chain residues in this neck region, contribute to provision of myosin's procoagulant surface.


Assuntos
Fator Xa/metabolismo , Miosinas/química , Miosinas/metabolismo , Protrombina/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Humanos , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Coelhos
16.
Sci Rep ; 9(1): 10196, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31308410

RESUMO

Gas flow behavior in porous media with micro- and nanoscale pores has always been attracted great attention. Gas transport mechanism in such pores is a complex problem, which includes continuous flow, slip flow and transition flow. In this study, the microtubes of quartz microcapillary and nanopores alumina membrane were used, and the gas flow measurements through the microtubes and nanopores with the diameters ranging from 6.42 µm to 12.5 nm were conducted. The experimental results show that the gas flow characteristics are in rough agreement with the Hagen-Poiseuille (H-P) equation in microscale. However, the flux of gas flow through the nanopores is larger than the H-P equation by more than an order of magnitude, and thus the H-P equation considerably underestimates gas flux. The Knudsen diffusion and slip flow coexist in the nanoscale pores and their contributions to the gas flux increase as the diameter decreases. The slip flow increases with the decrease in diameter, and the slip length decreases with the increase in driving pressure. Furthermore, the experimental gas flow resistance is less than the theoretical value in the nanopores and the flow resistance decreases along with the decrease in diameter, which explains the phenomenon of flux increase and the occurrence of a considerable slip length in nanoscale. These results can provide insights into a better understanding of gas flow in micro- and nanoscale pores and enable us to exactly predict and actively control gas slip.

17.
Methods Enzymol ; 622: 183-200, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31155052

RESUMO

G protein-coupled receptors (GPCRs) play a key role in signal transduction and human pathophysiological processes. Family B GPCRs are activated by a number of secreted peptide hormones, and engineering of these peptide ligands in order to improve stability and half-life, and therefore clinical efficacy has proven successful for drug discovery. In this chapter we discuss a novel peptide engineering strategy that combines peptide side chain stapling with covalent incorporation of a serum protein binding motif in a single step. The application of this approach to the enhancement of the helicity and stability of GLP-1R peptide agonists, resulting in their improved in vitro potencies, in vivo half-lives and ultimately efficacies, will be described. Discussion of the stapling technology and target selection rationale, peptide engineering and final biological characterization of the long-acting agonists will also be provided.


Assuntos
Ácidos Graxos/química , Ácidos Graxos/farmacologia , Peptídeos/química , Peptídeos/farmacologia , Receptores Acoplados a Proteínas G/agonistas , Sequência de Aminoácidos , Animais , Desenho de Fármacos , Descoberta de Drogas , Ácidos Graxos/farmacocinética , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Humanos , Ligantes , Modelos Moleculares , Peptídeos/farmacocinética , Polietilenoglicóis/química , Polietilenoglicóis/farmacocinética , Polietilenoglicóis/farmacologia , Estrutura Secundária de Proteína , Receptores Acoplados a Proteínas G/metabolismo
18.
Bioconjug Chem ; 30(1): 83-89, 2019 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-30543420

RESUMO

Peptide hormone relaxin-2, a member of the insulin family of peptides, plays a key role in hemodynamics and renal function and has shown preclinical efficacy in multiple disease models, including acute heart failure, fibrosis, preeclampsia, and corneal wound healing. Recently, serelaxin, a recombinant version of relaxin-2, has been studied in a large phase 3 clinical trial (RELAX-AHF-2) for acute decompensated heart failure patients with disappointing outcome. The poor in vivo half-life of relaxin-2 may have limited its therapeutic efficacy and long-term cardiovascular benefit. Herein, we have developed a semisynthetic methodology and generated potent, fatty acid-conjugated relaxin analogs with long-acting pharmacokinetic (PK) profile in rodents. The enhanced PK properties translated into improved and long-lasting pharmacodynamic effect in pubic ligament elongation (PLE) studies. The resultant novel relaxin analog, R9-13, represents the first long-acting relaxin-2 analog and could potentially improve the clinical efficacy and outcome for this important peptide hormone. This semisynthetic methodology could also be applied to other cysteine-rich peptides and proteins for half-life extension.


Assuntos
Desenho de Fármacos , Lipídeos/química , Relaxina/química , Relaxina/uso terapêutico , Sequência de Aminoácidos , Animais , Meia-Vida , Insuficiência Cardíaca/tratamento farmacológico , Humanos , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacocinética , Proteínas Recombinantes/uso terapêutico , Relaxina/farmacocinética
19.
Nat Chem ; 10(5): 540-548, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29610465

RESUMO

New methods capable of effecting cyclization, and forming novel three-dimensional structures while maintaining favourable physicochemical properties are needed to facilitate the development of cyclic peptide-based drugs that can engage challenging biological targets, such as protein-protein interactions. Here, we report a highly efficient and generally applicable strategy for constructing new types of peptide macrocycles using palladium-catalysed intramolecular C(sp3)-H arylation reactions. Easily accessible linear peptide precursors of simple and versatile design can be selectively cyclized at the side chains of either aromatic or modified non-aromatic amino acid units to form various cyclophane-braced peptide cycles. This strategy provides a powerful tool to address the long-standing challenge of size- and composition-dependence in peptide macrocyclization, and generates novel peptide macrocycles with uniquely buttressed backbones and distinct loop-type three-dimensional structures. Preliminary cell proliferation screening of the pilot library revealed a potent lead compound with selective cytotoxicity toward proliferative Myc-dependent cancer cell lines.


Assuntos
Carbono/química , Éteres Cíclicos/química , Hidrogênio/química , Compostos Macrocíclicos/química , Paládio/química , Peptídeos/química , Catálise , Linhagem Celular Tumoral , Ciclização , Teoria da Densidade Funcional , Humanos
20.
J Med Chem ; 61(7): 3218-3223, 2018 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-29528634

RESUMO

Glucagon-like peptide 2 (GLP-2) is a hormone that has been shown to stimulate intestinal growth and attenuate intestinal inflammation. Despite being efficacious in a variety of animal models of disease, its therapeutic potential is hampered by the short half-life in vivo. We now describe a highly potent, stapled long-acting GLP-2 analog, peptide 10, that has a more than 10-fold longer half-life than teduglutide and improved intestinotrophic and anti-inflammatory effects in mouse models of DSS-induced colitis.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Colite/tratamento farmacológico , Fármacos Gastrointestinais/farmacologia , Peptídeo 2 Semelhante ao Glucagon/farmacologia , Animais , Anti-Inflamatórios não Esteroides/síntese química , Anti-Inflamatórios não Esteroides/farmacocinética , Colite/induzido quimicamente , Reagentes de Ligações Cruzadas , AMP Cíclico/biossíntese , Sulfato de Dextrana , Desenho de Fármacos , Feminino , Fármacos Gastrointestinais/síntese química , Fármacos Gastrointestinais/farmacocinética , Peptídeo 2 Semelhante ao Glucagon/síntese química , Peptídeo 2 Semelhante ao Glucagon/farmacocinética , Meia-Vida , Intestinos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Conformação Molecular , Peptídeos/farmacocinética , Peptídeos/farmacologia
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