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BACKGROUND: The breeder rooster has played a pivotal role in poultry production by providing high-quality semen. Typically, fertility peaks between 30 and 40 weeks of age and then declines rapidly from 45 to 55 weeks of age. Research into improving fertility in aging roosters is essential to extend their productive life. While progress has been made, enhancing fertility in aging roosters remains a significant challenge. METHODS: To identify the genes related to promoting sperm remodeling in aged Houdan roosters, we combined changes in testis and semen quality with transcriptome sequencing (RNA-seq) to analyze the synchrony of semen quality and testis development. In this study, 350-day-old Houdan breeder roosters were selected for RNA-seq analysis in testis tissues from induced molting roosters (D group) and non-induced molting roosters (47DG group). All analyses of differentially expressed genes (DEGs) and functional enrichment were performed. Finally, we selected six DEGs to verify the accuracy of the sequencing by qPCR. RESULTS: Compared with the 47DG group, sperm motility (P < 0.05), sperm density (P < 0.01), and testis weight (P < 0.05) were significantly increased in roosters in the D group. Further RNA-seq analysis of the testis between the D group and 47DG group identified 61 DEGs, with 21 up-regulated and 40 down-regulated. Functional enrichment analysis showed that the DEGs were primarily enriched in the cytokine-cytokine receptor interaction, Wnt signaling pathway, MAPK signaling pathway, TGF-ß signaling pathway, and focal adhesion pathway. The qRT-PCR results showed that the expression trend of these genes was consistent with the sequencing results. WNT5A, FGFR3, AGTR2, TGFß2, ROMO1, and SLC26A7 may play a role in testis development and spermatogenesis. This study provides fundamental data to enhance the reproductive value of aging roosters.
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Pollos , Perfilación de la Expresión Génica , Espermatozoides , Testículo , Masculino , Animales , Espermatozoides/metabolismo , Pollos/genética , Testículo/metabolismo , Transcriptoma , Envejecimiento/genética , Análisis de Semen , Motilidad Espermática/genética , Restricción CalóricaRESUMEN
Dietary administration of a copper chelator, cuprizone (CPZ), has long been reported to induce intense and reproducible demyelination of several brain structures such as the corpus callosum. Despite the widespread use of CPZ as an animal model for demyelinating diseases such as multiple sclerosis (MS), the mechanism by which it induces demyelination and then allows robust remyelination is still unclear. An intensive mapping of the cell dynamics of oligodendrocyte (OL) lineage during the de- and remyelination course would be particularly important for a deeper understanding of this model. Here, using a panel of OL lineage cell markers as in situ hybridization (ISH) probes, including Pdgfra, Plp, Mbp, Mog, Enpp6, combined with immunofluorescence staining of CC1, SOX10, we provide a detailed dynamic profile of OL lineage cells during the entire course of the model from 1, 2, 3.5 days, 1, 2, 3, 4,5 weeks of CPZ treatment, as well as after 1, 2, 3, 4 weeks of recovery from CPZ treatment. The result showed an unexpected early death of mature OLs and response of OL progenitor cells (OPCs) in vivo upon CPZ challenge, and a prolonged upregulation of myelin-forming OLs compared to the intact control even 4 weeks after CPZ withdrawal. These data may serve as a basic reference system for future studies of the effects of any intervention on de- and remyelination using the CPZ model, and imply the need to optimize the timing windows for the introduction of pro-remyelination therapies in demyelinating diseases such as MS.
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Linaje de la Célula , Cuprizona , Enfermedades Desmielinizantes , Oligodendroglía , Cuprizona/toxicidad , Animales , Enfermedades Desmielinizantes/inducido químicamente , Enfermedades Desmielinizantes/patología , Oligodendroglía/efectos de los fármacos , Oligodendroglía/patología , Oligodendroglía/metabolismo , Modelos Animales de Enfermedad , Hibridación in Situ/métodos , Ratones Endogámicos C57BL , Ratones , Remielinización/efectos de los fármacos , Remielinización/fisiología , Masculino , Quelantes/toxicidad , Quelantes/farmacología , Vaina de Mielina/patología , Vaina de Mielina/efectos de los fármacos , Vaina de Mielina/metabolismoRESUMEN
The excessive deposition of abdominal adipocytes in chickens is detrimental to poultry production. However, the regulatory factors that affect abdominal adipogenesis in chickens are still poorly understood. SLC22A16 is differentially expressed in abdominal preadipocytes and 10-day differentiated adipocytes in chickens, but its role in regulating chicken adipogenesis has not been reported. In this study, the function of SLC22A16 in chicken abdominal preadipocytes was investigated. SLC22A16 is significantly upregulated during abdominal adipocyte differentiation. The overexpression of SLC2A16 upregulated the expression of adipogenic marker genes and proliferation-related genes, and promoted the proliferation of adipocytes and the accumulation of triglycerides. The knockdown of SLC22A16 downregulated the expression of adipogenic marker genes and proliferation-related genes, inhibited the proliferation of adipocytes, and impaired the accumulation of triglycerides in adipocytes. In addition, LNC6302 was differentially expressed in abdominal preadipocytes and mature adipocytes, and was significantly positively correlated with the expression of SLC22A16. Interference with LNC6302 inhibits the expression of adipogenic marker genes and proliferation-related genes. The data supported the notion that LNC6302 promotes the differentiation of chicken abdominal adipocytes by cis-regulating the expression of SLC22A16. This study identified the role of SLC22A16 in the differentiation and proliferation of chicken adipocytes, providing a potential target for improving abdominal adipogenesis in chickens.
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Adipocitos , Adipogénesis , Diferenciación Celular , Pollos , ARN Largo no Codificante , Animales , Adipocitos/metabolismo , Adipocitos/citología , Pollos/genética , Adipogénesis/genética , ARN Largo no Codificante/genética , Diferenciación Celular/genética , Proliferación Celular/genéticaRESUMEN
The "Yufen 1" H line chicken (YF) has excellent characteristics including early sexual maturity and high egg production, and the conservation of its genetic diversity is the core of the breeding activity. To overcome misrepresented breeds and protect the integrity of the germplasm genetic resources, it is important to develop accurate and convenient methods to identify YF. In this study, whole genome resequencing was performed on the YF population, and bioinformatics analysis was conducted by combining the data from different breeds. Linkage disequilibrium (LD) analysis revealed that YF had the slowest LD-decay rate, suggesting strong natural and artificial selection in its history. Through selective sweep analysis, 1,126 selected regions in YF were identified, which contained 163,661 single nucleotide polymorphisms (SNPs). In particular, 5 specific SNPs (SNP1: Chr2:45509616, SNP2: Chr2:45510792, SNP3: Chr9:13788193, SNP4: Chr9:13795646, SNP5: Chr9:13798154) were found exclusively in the YF population. Subsequently, PCR amplification and Sanger sequencing confirmed the presence of these 5 SNPs in YF. Finally, 4 SNPs (SNP1, SNP2, SNP4, SNP5) were screened and verified using the Kompetitive Allele Specific PCR (KASP) typing technique. These SNPs can be used as specific molecular identity cards (IDs) for YF authentication. The present study is of great significance to ensure sustainable conservation and promotion of YF germplasm resources.
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Pollos , Polimorfismo de Nucleótido Simple , Animales , Pollos/genética , Desequilibrio de Ligamiento , Análisis de Secuencia de ADN/veterinariaRESUMEN
BACKGROUND: Intramuscular fat (IMF) content is the major indicator for evaluating chicken meat quality due to its positive correlation with tenderness, juiciness, and flavor. An increasing number of studies are focusing on the functions of microRNAs (miRNAs) in intramuscular adipocyte differentiation. However, little is known about the association of miR-128-3p with intramuscular adipocyte differentiation. Our previous RNA-seq results indicated that miR-128-3p was differentially expressed at different periods in chicken intramuscular adipocytes, revealing a possible association with intramuscular adipogenesis. The purpose of this research was to investigate the biological functions and regulatory mechanism of miR-128-3p in chicken intramuscular adipogenesis. RESULTS: The results of a series of assays confirmed that miR-128-3p could promote the proliferation and inhibit the differentiation of intramuscular adipocytes. A total of 223 and 1,050 differentially expressed genes (DEGs) were identified in the mimic treatment group and inhibitor treatment group, respectively, compared with the control group. Functional enrichment analysis revealed that the DEGs were involved in lipid metabolism-related pathways, such as the MAPK and TGF-ß signaling pathways. Furthermore, target gene prediction analysis showed that miR-128-3p can target many of the DEGs, such as FDPS, GGT5, TMEM37, and ASL2. The luciferase assay results showed that miR-128-3p targeted the 3' UTR of FDPS. The results of subsequent functional assays demonstrated that miR-128-3p acted as an inhibitor of intramuscular adipocyte differentiation by targeting FDPS. CONCLUSION: miR-128-3p inhibits chicken intramuscular adipocyte differentiation by downregulating FDPS. Our findings provide a theoretical basis for the study of lipid metabolism and reveal a potential target for molecular breeding to improve meat quality.
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Pollos , MicroARNs , Animales , Pollos/genética , Diferenciación Celular/genética , Adipogénesis/genética , Regiones no Traducidas 3' , Adipocitos , MicroARNs/genéticaRESUMEN
The reproductive performance of breeder roosters has significant economic importance in the poultry industry. Breeder roosters have severely reduced semen quality with age and will be at risk of culling in the following years. In order to extend the use of breeder roosters, we drew on the induced molting model of hens and selected 35 Houdan roosters aged 50 wk for induced molting. By comparing the body weight, testicular weight, semen quality, and reproductive performance before and after induced molting, we found that induced molting could restore the body weight and testicular weight to the levels before molting (P > 0.05). At the same time, it significantly improved sperm motility (P < 0.05) and also improved reproductive performance such as fertilization rate and hatching rate. To further reveal the mechanism underlying the effects of induced molting on semen quality and reproductive performance in aged Houdan roosters, we collected testes from 3 periods: 1 d before fasting (F0), 15 d after fasting (F15), and 32 d after recovery feeding (R32) for transcriptome sequencing analysis. A total of 5,671 genes were detected in F0, F15, and R32, and trend analysis of the 5,671 differential genes showed 2 significant trends (profile 5 and profile 2). KEGG enrichment analysis of the genes in the 2 profiles, revealed significantly enriched pathway regulation of actin cytoskeleton. In the regulation of actin cytoskeleton pathway, we found a protein kinase gene (SRC) and a senescence gene (ROCK2). SRC was highly expressed at F15, leading to the phosphorylation of key substrates, which in turn disrupted the Sertoli cell spermatid connection and the spermiogenesis process, resulting in no mature spermatozoa produced from F15, SRC expression was inhibited at R32, the expression level was reduced, and mature spermatozoa reappeared. The senescence gene ROCK2 was highly expressed at F15 compared to F0 and R32, which may have been responsible for inducing senescence atrophy in the testes.
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Pollos , Análisis de Semen , Animales , Masculino , Femenino , Análisis de Semen/veterinaria , Pollos/genética , Suplementos Dietéticos/análisis , Muda , Transcriptoma , Motilidad Espermática , Espermatozoides/fisiología , Peso Corporal , Semen/fisiologíaRESUMEN
Chondrocutaneous branchial remnants (CCBRs) are rare congenital heterotopic tissue formations originating from the first or second embryonic branchial arches. Clinically, CCBRs are characterized predominantly by unilateral and solitary cartilaginous nodules found on the lower neck region. Herein, we present a case of CCBRs in a 9-year-old male patient who presented with horn-shaped projecting masses on either side of the anterior border of the sternocleidomastoid muscle. The pathological report following surgical resection revealed that the lesion was located in the dermis and consisted primarily of hyaline cartilage tissue enclosed by a fibrous capsule, with few local vascular proliferations. Based on the clinical and pathological features, the patient was ultimately diagnosed with congenital bilateral cervical chondrocutaneous branchial remnants.
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The effective protection and utilization of poultry resources depend on an accurate understanding of the genetic diversity and population structure. The breeding of the specialized poultry lineage "Yufen 1", with its defined characteristics, was approved by the China Poultry Genetic Resource Committee in 2015. Thus, to investigate the relationship between the progenitor H line and other poultry breeds, the genetic diversity and population structure of "Yufen 1" H line (YF) were investigated and compared with those of 2 commercial chicken breeds, the ancestor breed Red Jungle Fowls, and 11 Chinese indigenous chicken breeds based on a whole-genome resequencing approach using 8,112,424 SNPs. The genetic diversity of YF was low, and the rate of linkage disequilibrium decay was significantly slower than that of the other Chinese indigenous breeds. In addition, it was shown that the YF population was strongly selected during intensive breeding and that genetic resources have been seriously threatened, which highlights the need to establish a systematic conservation strategy as well as utilization techniques to maintain genetic diversity within YF. Moreover, a principal component analysis, a neighbor-joining tree analysis, a structure analysis, and genetic differentiation indices indicated that YF harbors a distinctive genetic resource with a unique genetic structure separate from that of Chinese indigenous breeds at the genome level. The findings provide a valuable resource and the theoretical basis for the further conservation and utilization of YF.
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Although epilepsy is one of the most common neurologic disorders, there is still a lack of effective therapeutic drugs for it. Recently, we synthesized a novel hydrogen sulfide (H2S) donor, which is found to reduce seizures in animal models effectively. But it remains to be determined for its mechanism. In the present study, we found that the novel H2S donor could reduce pilocarpine-induced seizures in mice. It alleviated the epileptic behavior, the hippocampal electroencephalography (EEG) activity of seizures, and the damage of hippocampal neurons in status epilepticus mice. In addition, the novel H2S donor could reduce microglial inflammatory response. It not only reduced the upregulation of pro-inflammatory markers [inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2)] in status epilepticus mice, but also increased the levels of microglial anti-inflammatory marker arginase-1 (Arg-1). In lipopolysaccharide-treated microglia BV2 cells, administration of the H2S donor also significantly reduced the lipopolysaccharide-induced upregulation of the expression of the pro-inflammatory markers and increased the expression of the anti-inflammatory markers. Thus, the novel H2S donor regulates microglial inflammatory profile in status epilepticus mice and in vitro. These results suggested that the novel H2S donor can reduce seizures and regulate microglial inflammatory profile, which may be a novel mechanism and potential therapeutic strategy of the H2S donor anti-seizures.
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Aquaporin 4 (AQP4), a water-specific channel protein locating on the astrocyte membrane, has been found to be antagonist, agonist and undergone closely related to epilepsy. Our previous study showed that inhibition of an N-methyl-D-aspartate receptor (NMDAR) subunit NR2A can suppress epileptic seizures, suggesting that AQP4 is potentially involved in NR2A-mediated epilepsy treatment. In this study, we aimed to explore the relevance of AQP4 in NR2A-mediated seizures treatment in pentylenetetrazol (PTZ)-induced rat models. We performed electroencephalogram (EEG) recording and examined AQP4 expression at mRNA and protein levels, and the downstream molecules of AQP4 as well. It showed that AQP4 expression was increased after the induction of seizures. Lateral ventricle pretreatment of NR2A inhibitor could mitigate the PTZ-induced seizures severity and counterbalance the increase of AQP4 expression. In contrast, NR2A activator that resulted in seizures aggravation could further augment the seizure-related elevations of AQP4 expression. Pharmacological inhibition of AQP4 alone could also suppress the PTZ-induced seizure activities, with decreased expressions of NF-κB p65, interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF)-α in the brain. The results indicated that increased expression of AQP4 might be an important mechanism involved in NR2A of NMDAR-mediated treatment for epileptic seizures, enlightening a potentially new target for seizures treatment.
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Acuaporina 4/efectos de los fármacos , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Convulsiones/tratamiento farmacológico , Animales , Acuaporina 4/metabolismo , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Pentilenotetrazol/efectos adversos , Pentilenotetrazol/metabolismo , Ratas Sprague-Dawley , Receptores de N-Metil-D-Aspartato/metabolismo , Convulsiones/metabolismoRESUMEN
CYP3A enzymes play a crucial role in metabolic clearance of a variety of xenobiotics. However, their genetic information and function remain unclear in molluscs. In the present study, two novel CYP3A genes i.e. McCYP3A-1 and McCYP3A-2 were identified and characterized from the thick shell mussel Mytilus coruscus, and their tissue distribution as well as the response to cadmium (Cd) and benzo[a]pyrene (B[α]P) exposure were addressed using real time quantitative RT-PCR (qRT-PCR) and erythromycin N-demethylase (ERND) assay. McCYP3A-1 and McCYP3A-2 possess typically domains of CYP family such as helix-C, helix-I, helix-K, PERF and the heme binding domain as well as the characteristic domains of CYP3s including six SRS motifs. McCYP3A-1 and McCYP3A-2 transcripts were constitutively expressed in all examined tissues with high expression level in digestive glands, hepatopancreas and gonads. Upon B[α]P exposure, McCYP3A-1 and McCYP3A-2 mRNA expression in digestive glands showed a pattern of up-regulation followed by down-regulation, while under Cd exposure, showed a time-dependent induction profile. In addition, ERND activity, generally used as an indicator of CYP3, increased in a time-dependent manner after exposure to Cd and B[α]P. These results collectively indicated that McCYP3A-1 and McCYP3A-2 are CYP3A family member and may play a potential role in metabolic clearance of xenobiotics. Meanwhile, the current results may provide some baseline data to support McCYP3A-1 and McCYP3A-2 as candidate biomarkers for monitoring of PAHs and heavy metal pollution.
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Organismos Acuáticos/enzimología , Benzo(a)pireno/toxicidad , Cadmio/toxicidad , Citocromo P-450 CYP3A/metabolismo , Mytilus/enzimología , Secuencia de Aminoácidos , Animales , Organismos Acuáticos/efectos de los fármacos , Secuencia de Bases , Citocromo P-450 CYP3A/química , Citocromo P-450 CYP3A/genética , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Mytilus/efectos de los fármacos , Filogenia , Distribución Tisular/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidadRESUMEN
Interleukin-1 receptor-associated kinase-4 (IRAK4) is considered as the most upstream kinase of IRAKs and plays a vital role in Toll-like receptor/Interleukin-1 receptor (TLR/IL-1R) signal transduction. In the present study, IRAK4 from thick shell mussel Mytilus coruscus (McIRAK4) was identified and characterized. McIRAK4 showed the most similarity to its counterparts in bivalves. The conserved death domain (DD) and catalytic domain of serine/threonine kinases (STKc) were predicted in all examined IRAK4s. McIRAK4 transcripts were constitutively expressed in all examined tissues with the higher expression level in immune related tissues, and were significantly induced in haemocytes upon lipopolysaccharide (LPS) and polyinosinic-polycytidylic acid (poly I:C) challenge. Further, the expression of McIRAK4 was obviously repressed by dsRNA mediated RNA interference (RNAi), meanwhile the proinflammatory cytokines TNF-alpha and IL17 were down-regulated while the antiinflammatory cytokine TGF-ß was up-regulated. Additionally, McIRAK4 showed a global cytoplasmic localization in HEK293T cells through fluorescence microscopy. These results collectively indicated that McIRAK4 is one member of IRAK4 subfamily and might play the potential signal transducer role in inflammatory response. The present study provides supplement for TLR-mediated signaling pathway triggered by pathogenic invasions in thick shell mussel, and contributes to the clarification of the innate immune response in molluscs.
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Regulación de la Expresión Génica/inmunología , Inmunidad Innata/genética , Quinasas Asociadas a Receptores de Interleucina-1/genética , Quinasas Asociadas a Receptores de Interleucina-1/inmunología , Mytilus/genética , Mytilus/inmunología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Perfilación de la Expresión Génica , Quinasas Asociadas a Receptores de Interleucina-1/química , Lipopolisacáridos/farmacología , Filogenia , Poli I-C/farmacología , Interferencia de ARN/inmunología , ARN Bicatenario/metabolismo , Alineación de SecuenciaRESUMEN
Tumor necrosis factor receptor-associated factor 6 (TRAF6) is one of the key adapter molecules in Toll-like receptor signal transduction that triggers downstream cascades involved in innate immunity. Despite of the well study in vertebrates, there is few data ascribe to this TRAF member in invertebrates, especially in bivalves. In the present study, a novel TRAF6 homologue termed McTRAF6 was firstly characterized in Mytilus coruscus. Like its counterparts in mammals, McTRAF6 shared the domain topology containing one RING domain, two zinc finger domains, one coiled-coil region and a MATH domain. McTRAF6 transcripts predominantly expressed in gills, digestive glands and hemocytes in M. coruscus, and were significantly up-regulated in hemocytes after challenge with lipopolysaccharide (LPS) and polyinosine-polycytidylic acid (poly I:C). Further, the subcellular localization in cytoplasm and the activation of Nk-κB or ISRE luciferase reporter by overexpressed McTRAF6 were identified in HEK293T cells. These results collectively indicate that McTRAF6 is a member of TRAF6 subfamily and plays a potential role in immune defense system against pathogenic agents invasions in thick shell mussel. To our knowledge, this is the first report on component of TLR signaling pathway in thick shell mussel, providing further evidence for the existence of TLR pathway in M. coruscus and contribute to clarify the innate immune system of thick shell mussel.
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Mytilus/genética , Factor 6 Asociado a Receptor de TNF/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , ADN Complementario/genética , Células HEK293 , Hemocitos/inmunología , Humanos , Inmunidad Innata , Lipopolisacáridos/farmacología , Mytilus/inmunología , FN-kappa B/inmunología , Poli I-C/farmacología , Transducción de Señal , Factor 6 Asociado a Receptor de TNF/inmunología , Receptores Toll-Like/inmunología , Regulación hacia ArribaRESUMEN
The electrochemical behavior of hydroquinone (HQ) was studied by cyclic voltammetry at a glassy carbon electrode (GCE) modified by a gel containing multi-walled carbon nanotubes (MWNTs) and room temperature ionic liquid (RTIL) of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF(6)). At the modified electrode, HQ showed a pair of quasi-reversible redox peaks. The cathodic peak current value (I(pc)) of HQ was 9.608 x 10(-4)A, which is 43 times larger than the one at the GCE, and 11 times larger than that of I(pc) at the MWNTs/GCE. Furthermore, the capabilities of electron transfer on these three electrodes were also investigated by electrochemical impedance spectroscopy (EIS), and the similar conclusion as cyclic voltammetry has drawn. Besides, we also characterized the surface morphology of the prepared composite film using the scanning electronic microscopy (SEM). The MWNTs were pulled away from the tangle in RTIL. The solvent effect of RTIL may be the reason of higher adsorption amount.
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Técnicas Electroquímicas/métodos , Hidroquinonas/química , Líquidos Iónicos/química , Nanotubos de Carbono/química , Técnicas Electroquímicas/instrumentación , Electrodos , Concentración de Iones de Hidrógeno , Imidazoles/química , Microscopía Electrónica de Rastreo , Modelos Químicos , Estructura Molecular , Nanotubos de Carbono/ultraestructura , Análisis Espectral/métodosRESUMEN
Poly (2-ethylacrylic acid) (PEAA) alkylamide derivatives were synthesized for constructing pH-sensitive liposomes by partially modification of carboxylic groups of PEAA with chemical reaction. These lipid derivatives of PEAA were synthesized by partially modification of carboxylic groups of PEAA with alkylamines. The acid-sensitive polymer associated liposomes were obtained by the method of polymer self-insertion in aqueous solutions through inserting hydrophobic lipid anchors of the polymer PEAA derivatives into the outer layer of vesicles. Factor effects on polymer insertion into liposomes were evaluated and the pH-sensitivity of the polymer associated liposomes was studied by calcein release assay. The PEAA-assoeiated-liposomes were prepared successfully by the methods of self-insertion. The PEAA-associated-liposomes are shown to be stable at neutral pH. (1) There was no correlate of anchor density of PEAA with length of the alkyl chain, but was positively correlated with the degree of PEAA modification. (2) Polymer insertion increased with initial ratio of polymer to lipid. (3) Unerting hydrophobic lipidr acidic conditions the associated polymer induces membrane disruption and fusion. (4) The PEAA-associated-liposomes shown pH-sensitive drug release property under acidic conditions. The anchored-poly (ethylacrylic acid) lipid derivatives can be useful in developing a potential pH sensitive drug delivery system.
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Acrilatos/síntesis química , Sistemas de Liberación de Medicamentos/métodos , Liposomas/química , Alcamidas Poliinsaturadas/síntesis química , Acrilatos/farmacocinética , Animales , Células COS , Chlorocebus aethiops , Fluoresceínas/metabolismo , Concentración de Iones de Hidrógeno , Liposomas/farmacocinética , Tamaño de la Partícula , Alcamidas Poliinsaturadas/farmacocinéticaRESUMEN
Poly(ethylacrylic acid) (PEAA) is a pH-sensitive polymer that undergoes a transition from a hydrophilic to a hydrophobic form as the pH is lowered from neutral to acidic values. In this work we show that pH sensitive liposomes capable of intracellular delivery can be constructed by inserting a lipid derivative of PEAA into preformed large unilamellar vesicles (LUV) using a simple one step incubation procedure. The lipid derivatives of PEAA were synthesized by reacting a small proportion (3%) of the carboxylic groups of PEAA with C10 alkylamines to produce C10-PEAA. Incubation of C10-PEAA with preformed LUV resulted in the association of up to 8% by weight of derivatized polymer with the LUV without inducing aggregation. The resulting C10-PEAA-LUV exhibited pH-dependent fusion and leakage of LUV contents on reduction of the external pH below pH 6.0 as demonstrated by lipid mixing and release of calcein encapsulated in the LUV. In addition, C10-PEAA-LUV exhibited pH dependent intracellular delivery properties following uptake into COS-7 cells with appreciable delivery to the cell cytoplasm as evidenced by the appearance of diffuse intracellular calcein fluorescence. It is demonstrated that the cytoplasmic delivery of calcein by C10-PEAA-LUV could be inhibited by agents (bafilomycin or chloroquine) that inhibit acidification of endosomal compartments, indicating that this intracellular delivery resulted from the pH-dependent destabilization of LUV and endosomal membranes by the PEAA component of the C10-PEAA-LUV. It is concluded that C10-PEAA-LUV represents a promising intracellular delivery system for in vitro and in vivo applications.