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1.
Anticancer Res ; 40(4): 1855-1866, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32234873

RESUMO

BACKGROUND/AIM: The resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib or erlotinib, is considered a major challenge in the treatment of patients with non-small cell lung cancer (NSCLC). Herein, we identified the critical roles of anterior gradient 2 (AGR2) in gefitinib (Gef) resistance of mutant NSCLC cells. MATERIALS AND METHODS: Using datasets from a pair of NSCLC-sensitive and NSCLC-resistant cells, immunoblotting, immunofluorescence and immunohistochemistry, and cell viability assays were applied to identify the effects of AGR2. RESULTS: AGR2 was found to be significantly over-expressed in Gef-resistant cells and was highly associated with drug resistance, proliferation, migration, and invasion of cancer cells. Moreover, AGR2 and ADAMTS6 formed a negative feedback loop in drug-resistant cells. CONCLUSION: Modulation of overexpression of AGR2 in mutant NSCLC cells may be an attractive therapeutic strategy for the treatment of EGFR-TKI-resistant NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Proliferação de Células/efeitos dos fármacos , Mucoproteínas/genética , Proteínas Oncogênicas/genética , Inibidores de Proteínas Quinases/farmacologia , Apoptose/efeitos dos fármacos , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Movimento Celular/genética , Sobrevivência Celular/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Cloridrato de Erlotinib/farmacologia , Gefitinibe/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Mutação , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Quinazolinas/farmacologia
2.
Life Sci ; 246: 117396, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32035130

RESUMO

AIMS: Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality worldwide. Decrease in NKG2D ligand levels and exhaustion of NK cells in HCC patients are major causes of immune escape, high recurrence, poor prognosis, and low overall survival. Enhancing the susceptibility of HCC to NK cells by upregulating NKG2DLs on tumor cells is an effective treatment strategy. This study aimed to identify the effect of the Anterior gradient 2 (AGR2)-derived peptide P1, which was reported to bind to HLA-A*0201 as an epitope, on both the expression of major histocompatibility complex class I-related chains A/B (MICA/B) on HCC cells and the cytotoxicity of NK cells. MAIN METHODS: The effect of P1 on MICA/B expression on HCC cells was determined by qRT-PCR, western blotting, and flow cytometry analysis. HCC cells were pre-treated with various pathway inhibitors to identify the molecular pathways associated with P1 treatment. The cytotoxicity of NK cells toward HCC was investigated by LDH cytotoxicity assay. The tumor-suppression effect of P1 was determined in vivo using a NOD/SCID mice HCC model. KEY FINDINGS: P1 significantly increased MICA/B expression on HCC cells, thereby enhancing their susceptibility to the cytotoxicity of NK cells in vitro and in vivo. Further, p38 MAPK cell signaling pathway inhibitor SB203580 significantly attenuated the effects of P1 in vivo and in vitro. SIGNIFICANCE: P1 upregulates MICA and MICB expression on HCC cells, thereby promoting their recognition and elimination by NK cells, which makes P1 an attractive novel immunotherapy agent.


Assuntos
Carcinoma Hepatocelular/metabolismo , Antígenos de Histocompatibilidade Classe I/metabolismo , Neoplasias Hepáticas/metabolismo , Mucoproteínas/fisiologia , Proteínas Oncogênicas/fisiologia , Animais , Western Blotting , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Humanos , Interferon gama/metabolismo , Camundongos Endogâmicos NOD , Camundongos SCID , Mucoproteínas/metabolismo , Transplante de Neoplasias , Proteínas Oncogênicas/metabolismo , Ratos , Reação em Cadeia da Polimerase em Tempo Real , Regulação para Cima
3.
Am J Physiol Cell Physiol ; 318(1): C40-C47, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31644305

RESUMO

The anterior gradient-2 (AGR2) is an endoplasmic reticulum (ER)-resident protein belonging to the protein disulfide isomerase family that mediates the formation of disulfide bonds and assists the protein quality control in the ER. In addition to its role in proteostasis, extracellular AGR2 is responsible for various cellular effects in many types of cancer, including cell proliferation, survival, and metastasis. Various OMICs approaches have been used to identify AGR2 binding partners and to investigate the functions of AGR2 in the ER and outside the cell. Emerging data showed that AGR2 exists not only as monomer, but it can also form homodimeric structure and thus interact with different partners, yielding different biological outcomes. In this review, we summarize the AGR2 "interactome" and discuss the pathological and physiological role of such AGR2 interactions.


Assuntos
Retículo Endoplasmático/metabolismo , Mucoproteínas/metabolismo , Proteínas Oncogênicas/metabolismo , Transdução de Sinais , Animais , Retículo Endoplasmático/patologia , Humanos , Complexos Multiproteicos , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas
4.
Mol Cancer ; 18(1): 187, 2019 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-31856843

RESUMO

BACKGROUND: The majority of breast cancer patients die of metastasis rather than primary tumors, whereas the molecular mechanisms orchestrating cancer metastasis remains poorly understood. Long noncoding RNAs (lncRNA) have been shown to regulate cancer occurrence and progression. However, the lncRNAs that drive metastasis in cancer patients and their underlying mechanisms are still largely unknown. METHODS: lncRNAs highly expressed in metastatic lymph nodes were identified by microarray. Survival analysis were made by Kaplan-Meier method. Cell proliferation, migration, and invasion assay was performed to confirm the phenotype of LINC02273. Tail vein model and mammary fat pad model were used for in vivo study. RNA pull-down and RIP assay were used to confirm the interaction of hnRNPL and LINC02273. Chromatin isolation by RNA purification followed by sequencing (ChIRP-seq), RNA-seq, ChIP-seq, and luciferase reporter assay reveal hnRNPL-LINC02273 regulates AGR2. Antisense oligonucleotides were used for in vivo treatment. RESULTS: We identified a novel long noncoding RNA LINC02273, whose expression was significantly elevated in metastatic lesions compared to the primary tumors, by genetic screen of matched tumor samples. Increased LINC02273 promoted breast cancer metastasis in vitro and in vivo. We further showed that LINC02273 was stabilized by hnRNPL, a protein increased in metastatic lesions, in breast cancer cells. Mechanistically, hnRNPL-LINC02273 formed a complex which activated AGR2 transcription and promoted cancer metastasis. The recruitment of hnRNPL-LINC02273 complex to AGR2 promoter region epigenetically upregulated AGR2 by augmenting local H3K4me3 and H3K27ac levels. Combination of AGR2 and LINC02273 was an independent prognostic factor for predicting breast cancer patient survival. Moreover, our data revealed that LINC02273-targeting antisense oligonucleotides (ASO) substantially inhibited breast cancer metastasis in vivo. CONCLUSIONS: Our findings uncover a key role of LINC02273-hnRNPL-AGR2 axis in breast cancer metastasis and provide potential novel therapeutic targets for metastatic breast cancer intervention.


Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Epigênese Genética , Regulação Neoplásica da Expressão Gênica , Mucoproteínas/genética , Proteínas Oncogênicas/genética , RNA Longo não Codificante/genética , Animais , Neoplasias da Mama/metabolismo , Neoplasias da Mama/mortalidade , Linhagem Celular Tumoral , Proliferação de Células , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , Modelos Biológicos , Metástase Neoplásica , Estadiamento de Neoplasias , Prognóstico , Interferência de RNA , Ensaios Antitumorais Modelo de Xenoenxerto
5.
Elife ; 82019 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-31868593

RESUMO

Sexual selection can explain the rapid evolution of fertilization proteins, yet sperm proteins evolve rapidly even if not directly involved in fertilization. In the marine mollusk abalone, sperm secrete enormous quantities of two rapidly evolving proteins, lysin and sp18, that are stored at nearly molar concentrations. We demonstrate that this extraordinary packaging is achieved by associating into Fuzzy Interacting Transient Zwitterion (FITZ) complexes upon binding the intrinsically disordered FITZ Anionic Partner (FITZAP). FITZ complexes form at intracellular ionic strengths and, upon exocytosis into seawater, lysin and sp18 are dispersed to drive fertilization. NMR analyses revealed that lysin uses a common molecular interface to bind both FITZAP and its egg receptor VERL. As sexual selection alters the lysin-VERL interface, FITZAP coevolves rapidly to maintain lysin binding. FITZAP-lysin interactions exhibit a similar species-specificity as lysin-VERL interactions. Thus, tethered molecular arms races driven by sexual selection can generally explain rapid sperm protein evolution.


Assuntos
Evolução Molecular , Mucoproteínas/genética , Proteínas/genética , Seleção Genética , Sequência de Aminoácidos/genética , Animais , Proteínas do Ovo/genética , Feminino , Fertilização/genética , Gastrópodes/genética , Gastrópodes/crescimento & desenvolvimento , Espectroscopia de Ressonância Magnética , Masculino , Espermatozoides/química , Espermatozoides/metabolismo
6.
J Clin Exp Hematop ; 59(4): 187-195, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31866620

RESUMO

The antigenic heterogeneity of the reticular framework of the white pulp and marginal zone is well documented in the human adult spleen. Immunostaining of α-smooth muscle actin characterizes the heterogeneity of the reticular framework of the white pulp and marginal zone. In the human spleen, the blood cells flow in an open circulation. T and B lymphocytes flow out from the arterial terminal, and migrate in the reticular framework. Homing of lymphocytes to lymphoid tissues is regulated by selective interactions between cell surface homing receptors and tissue vascular addressins at sites of lymphocyte recruitment from the blood. In the present study, mucosal addressin cell adhesion molecule-1 was selectively expressed on α-smooth muscle actin-positive reticular framework. The reticular framework may function in lymphocyte homing and segregation into the periarteriolar lymphoid sheath, lymph follicle and marginal zone.


Assuntos
Actinas/biossíntese , Linfócitos B/metabolismo , Moléculas de Adesão Celular/biossíntese , Regulação da Expressão Gênica , Mucoproteínas/biossíntese , Baço/metabolismo , Linfócitos T/metabolismo , Linfócitos B/ultraestrutura , Humanos , Baço/ultraestrutura , Linfócitos T/ultraestrutura
7.
Planta ; 251(1): 19, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31781905

RESUMO

MAIN CONCLUSION: Arabinogalactan protein content in both root extracellular trap and root exudates varies in three Sahelian woody plant species that are differentially tolerant to drought. At the root tip, mature root cap cells, mainly border cells (BCs)/border-like cells (BLCs) and their associated mucilage, form a web-like structure known as the "Root Extracellular Trap" (RET). Although the RET along with the entire suite of root exudates are known to influence rhizosphere function, their features in woody species is poorly documented. Here, RET and root exudates were analyzed from three Sahelian woody species with contrasted sensitivity to drought stress (Balanites aegyptiaca, Acacia raddiana and Tamarindus indica) and that have been selected for reforestation along the African Great Green Wall in northern Senegal. Optical and transmission electron microscopy show that Balanites aegyptiaca, the most drought-tolerant species, produces only BC, whereas Acacia raddiana and Tamarindus indica release both BCs and BLCs. Biochemical analyses reveal that RET and root exudates of Balanites aegyptiaca and Acacia raddiana contain significantly more abundant arabinogalactan proteins (AGPs) compared to Tamarindus indica, the most drought-sensitive species. Root exudates of the three woody species also differentially impact the plant soil beneficial bacteria Azospirillum brasilense growth. These results highlight the importance of root secretions for woody species survival under dry conditions.


Assuntos
Acacia/metabolismo , Balanites/metabolismo , Exsudatos de Plantas/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/metabolismo , Tamarindus/metabolismo , Madeira/metabolismo , Acacia/citologia , Acacia/ultraestrutura , Azospirillum/metabolismo , Balanites/citologia , Balanites/ultraestrutura , Forma Celular , Monossacarídeos/análise , Mucoproteínas/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/ultraestrutura , Plântula/citologia , Tamarindus/citologia
8.
BMC Genomics ; 20(1): 881, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31752667

RESUMO

BACKGROUND: Targeted therapy for non-small cell lung cancer is histology dependent. However, histological classification by routine pathological assessment with hematoxylin-eosin staining and immunostaining for poorly differentiated tumors, particularly those from small biopsies, is still challenging. Additionally, the effectiveness of immunomarkers is limited by technical inconsistencies of immunostaining and lack of standardization for staining interpretation. RESULTS: Using gene expression profiles of pathologically-determined lung adenocarcinomas and squamous cell carcinomas, denoted as pADC and pSCC respectively, we developed a qualitative transcriptional signature, based on the within-sample relative gene expression orderings (REOs) of gene pairs, to distinguish ADC from SCC. The signature consists of two genes, KRT5 and AGR2, which has the stable REO pattern of KRT5 > AGR2 in pSCC and KRT5 < AGR2 in pADC. In the two test datasets with relative unambiguous NSCLC types, the apparent accuracy of the signature were 94.44 and 98.41%, respectively. In the other integrated dataset for frozen tissues, the signature reclassified 4.22% of the 805 pADC patients as SCC and 12% of the 125 pSCC patients as ADC. Similar results were observed in the clinical challenging cases, including FFPE specimens, mixed tumors, small biopsy specimens and poorly differentiated specimens. The survival analyses showed that the pADC patients reclassified as SCC had significantly shorter overall survival than the signature-confirmed pADC patients (log-rank p = 0.0123, HR = 1.89), consisting with the knowledge that SCC patients suffer poor prognoses than ADC patients. The proliferative activity, subtype-specific marker genes and consensus clustering analyses also supported the correctness of our signature. CONCLUSIONS: The non-subjective qualitative REOs signature could effectively distinguish ADC from SCC, which would be an auxiliary test for the pathological assessment of the ambiguous cases.


Assuntos
Adenocarcinoma de Pulmão/classificação , Carcinoma de Células Escamosas/classificação , Neoplasias Pulmonares/classificação , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/metabolismo , Adenocarcinoma de Pulmão/patologia , Idoso , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Feminino , Humanos , Queratina-5/genética , Queratina-5/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Mucoproteínas/genética , Mucoproteínas/metabolismo , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Transcriptoma
9.
Plant Sci ; 287: 110191, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481222

RESUMO

As an extracellular arabinogalactan protein (AGP) containing a non-specific lipid transfer protein (nsLTP) domain, xylogen mediates the local intercellular communication required for tracheary element (TE) differentiation in Zinnia cell culture. Although XYLP (xylogen-like protein) gene families have been reported in Arabidopsis and rice, no comprehensive analysis has been performed in woody plants. In this work, 31 XYLP genes in five phylogenetic groups were identified from Populus trichocarpa genome and a comprehensive bioinformatic analysis including gene and protein structures, chromosomal locations and duplication events were conducted. In-silico data and qRT-PCR results indicated that PtXYLP1 is predominantly expressed in poplar apex, young leaves and roots, while PtXYLP2 is uniformly expressed across a variety of tissues with a low abundance. Analysis on PtXYLP1pro:GUS and PtXYLP2pro:GUS in Arabidopsis revealed their differential expression patterns during seed germination and specific inductions by exogenously applied phytohormones including auxin, cytokinin and GA. When overexpressed in Arabidopsis, PtXYLP1 but not PtXYLP2 resulted in cotyledons with defective venation patterns and interrupted secondary (2°) vein loops, which phenotype was underpinned by the down-regulation of genes indispensably required by embryonic venation development at procambium and/or vessel level.


Assuntos
Regulação da Expressão Gênica de Plantas/genética , Genoma de Planta/genética , Mucoproteínas/genética , Populus/genética , Animais , Arabidopsis/citologia , Arabidopsis/genética , Cotilédone/citologia , Cotilédone/genética , Genes Reporter , Fenótipo , Filogenia , Reguladores de Crescimento de Planta/metabolismo , Folhas de Planta/citologia , Folhas de Planta/genética , Proteínas de Plantas/genética , Raízes de Plantas/citologia , Raízes de Plantas/genética , Plantas Geneticamente Modificadas , Populus/citologia
11.
Carbohydr Polym ; 224: 115170, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472872

RESUMO

The emulsification properties of the standard (STD), matured (EM2 and EM10) and fractionated gum arabic samples via phase separation induced molecular fractionation were investigated to find out how the content of arabinogalactan protein (AGP) complex affects the resulting emulsion properties. Phase separation and the accompanying molecular fractionation were induced by mixing with different hydrocolloids including hyaluronan (HA), carboxymethyl cellulose (CMC), and maltodextrin (MD). Increase of AGP content from 11 to 28% resulted in the formation of emulsions with relatively smaller droplet sizes and better stability. Further increase in the AGP content to 41% resulted in the formation of emulsions with larger droplets. In spite of the larger droplets sizes, these emulsions were extremely stable. In addition, the emulsions prepared with GA higher AGP content better stability in the presence of ethanol. The results indicate that AGP content plays a vital role in emulsion stability and droplet size.


Assuntos
Goma Arábica/química , Mucoproteínas/química , Emulsões , Etanol/química , Ácido Hialurônico/química , Proteínas de Plantas/química
12.
Carbohydr Res ; 485: 107816, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31546145

RESUMO

Arabinogalactans (AGs) and arabinogalactan-proteins (AGPs) were partially purified from an extract of fruits of the European pear (Pyrus communis L.) by DEAE-cellulose ion-exchange and Sepharose 6B gel-filtration chromatography. Among 7 AG(P)-containing fractions, a neutral AGP (SE-1) was confirmed to be highly purified (Mr 67,000) and rich in L-Ara and Gal; this fraction included a small amount (2.6%, w/w) of protein and showed the highest reactivity forming precipitate with ß-Glc Yariv reagent among the 7 fractions, the intensity of which was comparable to that of gum arabic, a standard AGP. Another accompanying minor low-Mr neutral AGP (SE-2; Mr approx. 7200) still contained other polysaccharide (starch fragments) and did not show Yariv reactivity. The carbohydrate moieties of SE-1 consisted of consecutive (1 → 3)-linked ß-galactosyl backbone chains substituted with side chains of (1 → 6)-linked ß-galactosyl residues at O-6, to which mainly single α-l-arabinofuranosyl residues were attached through O-3. This structural feature was also observed for SE-2. Successive digestion of SE-1 with α-l-arabinofuranosidase and exo-ß-(1 → 3)-galactanase with the aid of endo-ß-(1 → 3)-galactanase released most (more than 98%, w/w) of the carbohydrate moieties as low-Mr fragments. These consisted of free L-Ara and Gal, and a series of ß-(1 → 6)-galactooligosaccharides with degree of polymerization (dp) up to at least 17, indicative of attachment of (1 → 6)-linked ß-galactosyl side chains of varying length along the (1 → 3)-linked ß-galactosyl backbone chains.


Assuntos
Frutas/química , Mucoproteínas/química , Pyrus/química , Glicosilação , Mucoproteínas/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , beta-Galactosidase/metabolismo
13.
Plant Reprod ; 32(4): 353-370, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31501923

RESUMO

KEY MESSAGE: The fasciclin-like arabinogalactan proteins organization into four groups is conserved and may be related to specific roles in developmental processes across angiosperms. Fasciclin-like arabinogalactan proteins (FLAs) are a subclass of arabinogalactan proteins (AGPs), which contain fasciclin-like domains in addition to typical AGP domains. FLAs are present across all embryophytes, and despite their low overall sequence similarity, conserved regions that define the fasciclin functional domain (FAS) have been identified, suggesting that the cell adhesion property is also conserved. FLAs in Arabidopsis have been organized into four subgroups according to the number and distribution of functional domains. Recent studies associated FLAs with cell wall-related processes where domain organization seemed to be related to functional roles. In Arabidopsis, FLAs containing a single FAS domain were found to be important for the integrity and elasticity of the plant cell wall matrix, and FLAs with two FAS domains and two AGP domains were found to be involved in maintaining proper cell expansion under salt stress conditions. The main purpose of the present work was to elucidate the expression pattern of selected FLA genes during embryo and seed development using RT-qPCR. AtFLA8 and AtFLA10, two Arabidopsis genes that stood out in previous microarray studies of embryo development, were further examined using promoter-driven gene reporter analyses. We also studied the expression of cork oak FLA genes and found that their expression partially parallels the expression patterns of the putative AtFLA orthologs. We propose that the functional organization of FLAs is conserved and may be related to fundamental aspects of embryogenesis and seed development across angiosperms. Phylogenetic studies were performed, and we show that the same basic four-subgroup organization described for Arabidopsis FLA gene classification is valid for most Arabidopsis FLA orthologs of several plant species, namely poplar, corn and cork oak.


Assuntos
Arabidopsis/genética , Mucoproteínas/genética , Sementes/genética , Arabidopsis/fisiologia , Regulação da Expressão Gênica de Plantas , Filogenia , Proteínas de Plantas/genética
14.
Appl Microbiol Biotechnol ; 103(18): 7451-7457, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31384991

RESUMO

Arabinogalactan proteins (AGPs) are complex plant proteoglycans that function as dietary fiber utilized by human intestinal bacteria such as Bifidobacterium and Bacteroides species. However, the degradative mechanism is unknown because of the complexity of sugar chains of AGPs as well as variation among plant species and organs. Recently, AGP degradative enzymes have been characterized in Bifidobacterium and Bacteroides species. In this review, we summarize the characteristics and functions of AGP degradative enzymes in human intestinal bacteria.


Assuntos
Bactérias/enzimologia , Intestinos/microbiologia , Mucoproteínas/metabolismo , Plantas/metabolismo , Bacteroides/enzimologia , Bifidobacterium/enzimologia , Parede Celular/metabolismo , Fibras na Dieta/metabolismo , Humanos , Proteínas de Plantas/metabolismo
15.
Carbohydr Polym ; 220: 247-255, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31196547

RESUMO

A water-soluble polysaccharide (type II arabinogalactan-protein) extracted from the gum exudate of the native New Zealand puka tree (Meryta sinclairii), was characterised for its molecular, rheological and physicochemical properties. In 0.1 M NaCl, the weight average molecular weight (Mw) of puka gum is 5.9 × 106 Da with an RMS radius of 56 nm and z-average hydrodynamic radius of 79 nm. The intrinsic viscosity of the polysaccharide is 57 ml/g with a coil overlap concentration 15% w/w. Together, the shape factor, p, of 0.70 (exponent of RMS radius vs. hydrodynamic radius), Smidsrød-Haug's stiffness parameter B of 0.031 and Mark-Houwink exponent α of 0.375 indicate that the polysaccharide adopts a spherical conformation in solution, similar to gum arabic. The pKa is 1.8. The polysaccharide exhibits a Newtonian to shear-thinning behaviour from 0.2 to 25% w/w. Viscosity of the polysaccharide (1 s-1) decreases with decreasing concentration, increasing temperature, ionic strength, and at acidic pH.


Assuntos
Araliaceae/metabolismo , Mucoproteínas/química , Gomas Vegetais/química , Polissacarídeos/química , Árvores/metabolismo , Peso Molecular , Mucoproteínas/isolamento & purificação , Nova Zelândia , Gomas Vegetais/isolamento & purificação , Proteínas de Plantas/química , Proteínas de Plantas/isolamento & purificação , Polissacarídeos/isolamento & purificação , Reologia , Solubilidade , Viscosidade
16.
Plant Physiol Biochem ; 139: 681-690, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31054470

RESUMO

Arabinogalactan proteins (AGPs) are ubiquitous components of the amorphous plant extracellular matrix. They are characterized by a high proportion of sugar moieties, heterogeneity of their protein backbone and carbohydrate chains. It is known that AGPs form a complex network with other basic constituents in cell wall thus it may also play a role in softening process of fruit. The use of enzymatic degradation and cell wall polysaccharide directed probes are valid analytical tools for the study of developmental modification of the fruit structure. However, it is unknown whether pectolytic enzymes affect AGPs. Thus, the aim of the current work is to detect AGP epitopes in situ to understand the impact of selected degradation enzymes on various carbohydrate moieties of AGPs. Secondly, there are no data with clarification of the impact of vitamin C on fruit ripening processes at the cellular level; hence, we also focused on the effect of vitamin C on the arrangement of AGPs as important constituents of the polysaccharide-proteoglycan network in the fruit cell wall. The results indicate that the distribution of the examined AGP carbohydrate moieties differs, which are related to changes in tissue architecture. The absence of glycan chains causes disruption in establishment of correlations between cell wall constituents and rearrangement in the cell wall structure. The induced modifications of cell walls are not comparable to alterations occurring in naturally ripening fruit, which allows a conclusion that the synergistic action of a wide variety of factors influences ripening.


Assuntos
Ácido Ascórbico/metabolismo , Frutas/metabolismo , Lycopersicon esculentum/metabolismo , Mucoproteínas/metabolismo , Parede Celular/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo
17.
Int J Mol Sci ; 20(10)2019 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-31130622

RESUMO

Plants frequently encounter diverse abiotic stresses, one of which is environmental thermal stress. To cope with these stresses, plants have developed a range of mechanisms, including altering the cell wall architecture, which is facilitated by the arabinogalactan proteins (AGP) and extensins (EXT). In order to characterise the localisation of the epitopes of the AGP and EXT, which are induced by the stress connected with a low (4 °C) or a high (40 °C) temperature, in the leaves of Brachypodium distachyon, we performed immunohistochemical analyses using the antibodies that bind to selected AGP (JIM8, JIM13, JIM16, LM2 and MAC207), pectin/AGP (LM6) as well as EXT (JIM11, JIM12 and JIM20). The analyses of the epitopes of the AGP indicated their presence in the phloem and in the inner bundle sheath (JIM8, JIM13, JIM16 and LM2). The JIM16 epitope was less abundant in the leaves from the low or high temperature compared to the control leaves. The LM2 epitope was more abundant in the leaves that had been subjected to the high temperatures. In the case of JIM13 and MAC207, no changes were observed at the different temperatures. The epitopes of the EXT were primarily observed in the mesophyll and xylem cells of the major vascular bundle (JIM11, JIM12 and JIM20) and no correlation was observed between the presence of the epitopes and the temperature stress. We also analysed changes in the level of transcript accumulation of some of the genes encoding EXT, EXT-like receptor kinases and AGP in the response to the temperature stress. In both cases, although we observed the upregulation of the genes encoding AGP in stressed plants, the changes were more pronounced at the high temperature. Similar changes were observed in the expression profiles of the EXT and EXT-like receptor kinase genes. Our findings may be relevant for genetic engineering of plants with increased resistance to the temperature stress.


Assuntos
Brachypodium/metabolismo , Glicoproteínas/metabolismo , Hidroxiprolina/metabolismo , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Brachypodium/genética , Resposta ao Choque Frio , Regulação da Expressão Gênica de Plantas , Glicoproteínas/genética , Resposta ao Choque Térmico , Hidroxiprolina/genética , Mucoproteínas/genética , Mucoproteínas/metabolismo , Folhas de Planta/genética , Proteínas de Plantas/genética
18.
Plant Reprod ; 32(3): 291-305, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31049682

RESUMO

KEY MESSAGE: AGP-rich glycoproteins mediate pollen-ovule interactions and cell patterning in the embryo sac of apple before and after fertilization. Glycoproteins are significant players in the dialog that takes place between growing pollen tubes and the stigma and style in the angiosperms. Yet, information is scarce on their possible involvement in the ovule, a sporophytic organ that hosts the female gametophyte. Apple flowers have a prolonged lapse of time between pollination and fertilization, offering a great system to study the developmental basis of glycoprotein secretion and their putative role during the last stages of the progamic phase and early seed initiation. For this purpose, the sequential pollen tube elongation within the ovary was examined in relation to changes in arabinogalactan proteins (AGPs) in the tissues of the ovule before and after fertilization. To evaluate what of these changes are developmentally regulated, unpollinated and pollinated flowers were compared. AGPs paved the pollen tube pathway in the ovules along the micropylar canal, and the nucellus entrance toward the synergids, which also developmentally accumulated AGPs at the filiform apparatus. Glycoproteins vanished from all these tissues following pollen tube passage, strongly suggesting a role in pollen-ovule interaction. In addition, AGPs marked the primary cell walls of the haploid cells of the female gametophyte, and they further built up in the cell walls of the embryo sac and developing embryo, layering the interactive walls of the three generations hosted in the ovule, the maternal sporophytic tissues, the female gametophyte, and the developing embryo.


Assuntos
Malus/fisiologia , Mucoproteínas/metabolismo , Flores/embriologia , Flores/fisiologia , Malus/embriologia , Óvulo Vegetal/embriologia , Óvulo Vegetal/fisiologia , Proteínas de Plantas/metabolismo , Pólen/embriologia , Pólen/fisiologia , Tubo Polínico/embriologia , Tubo Polínico/fisiologia , Polinização , Reprodução , Sementes/embriologia , Sementes/fisiologia
19.
Ann Anat ; 224: 161-171, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31121286

RESUMO

The microvascular architecture of the spleen plays an important role in the immunological function of this organ. The different types of vessels are related to different reticular cells each with their own immunomodulatory functions. The present study describes an immunohistochemical and morphometric analysis of the various types of vessels in 21 human autopsy non-pathological splenic samples. On an area of 785,656.37 µm2 for each sample, we classified and quantified the type and number of vascular structures, each according to their morphology and immunohistochemical profile, and obtained the ratios between them. The distribution of trabecular vessels and the characteristics of the venules are reviewed. In our material the so-called "cavernous perimarginal sinus" (anatomical structure previously described by Schmidt et al., 1988) was observed and interpreted as a curvilinear venule shaped by the follicle in contact with the trabecular vein. Our material comprised 261 trabeculae (containing 269 arterial sections and 508 venous sections), 30,621 CD34+ capillaries, 7739 CD271+ sheathed capillaries, 2588 CD169+ sheathed capillaries, and 31,124 CD8+ sinusoids. The total area (TA) (14,765,714.88 µm2) occupied by the sinusoidal sections of the 21 cases was much higher than the TA of the capillary sections (1,700,269.83 µm2). Similarly, the TA (651,985 µm2) occupied by the sections of the trabecular veins was much higher than the TA of the trabecular arteries (88,594 µm2). The total number of CD34+ capillaries and of sinusoids CD8+ was similar for the sum of the 21 cases, nevertheless there were large differences in each case. Statistically the hypothesis that the number of capillaries and sinusoids are present with the same frequency is discarded. In view of the absence of a numerical correlation between capillaries and sinusoids, we postulate that very possibly the arterial and the venous vascular trees are two anatomically independent structures separated by the splenic cords. We believe that this is the first work where splenic microvascularization is simultaneously approached from a morphometric and immunohistochemical point of view.


Assuntos
Microvasos/anatomia & histologia , Microvasos/química , Baço/irrigação sanguínea , Actinas/imunologia , Adapaleno/imunologia , Antígenos CD34/imunologia , Arteríolas/anatomia & histologia , Arteríolas/química , Autopsia , Antígenos CD8/imunologia , Patologia Legal , Humanos , Imunoglobulinas/imunologia , Imuno-Histoquímica , Mucoproteínas/imunologia , Molécula-1 de Adesão Celular Endotelial a Plaquetas/imunologia , Lectina 1 Semelhante a Ig de Ligação ao Ácido Siálico/imunologia , Baço/anatomia & histologia , Artéria Esplênica/anatomia & histologia , Artéria Esplênica/química
20.
EMBO Mol Med ; 11(6)2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31040128

RESUMO

Anterior gradient 2 (AGR2) is a dimeric protein disulfide isomerase family member involved in the regulation of protein quality control in the endoplasmic reticulum (ER). Mouse AGR2 deletion increases intestinal inflammation and promotes the development of inflammatory bowel disease (IBD). Although these biological effects are well established, the underlying molecular mechanisms of AGR2 function toward inflammation remain poorly defined. Here, using a protein-protein interaction screen to identify cellular regulators of AGR2 dimerization, we unveiled specific enhancers, including TMED2, and inhibitors of AGR2 dimerization, that control AGR2 functions. We demonstrate that modulation of AGR2 dimer formation, whether enhancing or inhibiting the process, yields pro-inflammatory phenotypes, through either autophagy-dependent processes or secretion of AGR2, respectively. We also demonstrate that in IBD and specifically in Crohn's disease, the levels of AGR2 dimerization modulators are selectively deregulated, and this correlates with severity of disease. Our study demonstrates that AGR2 dimers act as sensors of ER homeostasis which are disrupted upon ER stress and promote the secretion of AGR2 monomers. The latter might represent systemic alarm signals for pro-inflammatory responses.


Assuntos
Estresse do Retículo Endoplasmático , Retículo Endoplasmático/metabolismo , Mucoproteínas/metabolismo , Proteínas Oncogênicas/metabolismo , Multimerização Proteica , Proteostase , Animais , Retículo Endoplasmático/genética , Células HEK293 , Humanos , Masculino , Camundongos , Mucoproteínas/genética , Proteínas Oncogênicas/genética
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