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  • Functional integrin subunits regulating cell-matrix interactions in the intervertebral disc. 17318895

    Cellular interactions with the extracellular matrix are key factors regulating cell survival, differentiation, and response to environmental stimuli in cartilagenous tissues. Much is known about the extracellular matrix proteins in the intervertebral disc (IVD) and their variations with region, age, or degenerative state of the tissue. In contrast, little is known of the integrin cell surface receptors that directly bind to and interact with these matrix proteins in the IVD. In almost all tissues, these integrin-mediated cell-matrix interactions are important for transducing environmental cues arising from mechanical stimuli, matrix degradation fragments, and cytokines into intracellular signals. In this study, cells from the nucleus pulposus and anulus fibrosus regions of porcine IVDs were analyzed via flow cytometry to quantify integrin expression levels upon isolation and after monolayer culture. Assays of cell attachment to collagens, fibronectin, and laminin were performed after functional blocking of select integrin subunits to evaluate the role of specific integrins in cell attachment. In situ distribution and co-localization of integrins and laminin were also characterized. Results identify integrin receptors critical for IVD cell interactions with collagens (alpha1beta1) and fibronectin (alpha5beta1). Additionally, dramatic differences in cell-laminin interactions were observed between cells of the nucleus and anulus regions, including differences in alpha6 integrin expression, cell adhesion to laminin, and in situ pericellular environments. These findings suggest laminin-cell interactions may be important and unique to the nucleus pulposus region of the IVD. The results of this study provide new information on functional cell-matrix interactions in tissues of the IVD.
    Tipo de documento:
    Referencia
    Referencia del producto:
    CBL605
    Nombre del producto:
    Rat IgG2a Negative Control, clone DD13

  • Abca1 deficiency affects Alzheimer's disease-like phenotype in human ApoE4 but not in ApoE3-targeted replacement mice. 22993429

    ATP-binding cassette transporter A1 (ABCA1) transporter regulates cholesterol efflux and is an essential mediator of high-density lipoprotein (HDL) formation. In amyloid precursor protein (APP) transgenic mice, Abca1 deficiency increased amyloid deposition in the brain paralleled by decreased levels of Apolipoprotein E (ApoE). The APOEε4 allele is the major genetic risk factor of sporadic Alzheimer's disease (AD). Here, we reveal the effect of Abca1 deficiency on phenotype in mice expressing human ApoE3 or ApoE4. We used APP/E3 and APP/E4 mice generated by crossing APP/PS1ΔE9 transgenic mice to human APOE3- and APOE4-targeted replacement mice and examined Abca1 gene dose effect on amyloid deposition and cognition. The results from two behavior tests demonstrate that lack of one copy of Abca1 significantly exacerbates memory deficits in APP/E4/Abca1(-/+) but not in APP/E3/Abca1(-/+) mice. The data for amyloid plaques and insoluble amyloid-β (Aβ) also show that Abca1 hemizygosity increases Aβ deposition only in APP/E4/Abca1(-/+) but not in APP/E3/Abca1(-/+) mice. Our in vivo microdialysis assays indicate that Abca1 deficiency significantly decreases Aβ clearance in ApoE4-expressing mice, while the effect of Abca1 on Aβ clearance in ApoE3-expressing mice was insignificant. In addition, we demonstrate that plasma HDL and Aβ42 levels in APP/E4/Abca1(-/+) mice are significantly decreased, and there is a negative correlation between plasma HDL and amyloid plaques in brain, suggesting that plasma lipoproteins may be involved in Aβ clearance. Overall, our results prove that the presence of functional Abca1 significantly influences the phenotype of APP mice expressing human ApoE4 and further substantiate therapeutic approaches in AD based on ABCA1-APOE regulatory axis.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AB947
    Nombre del producto:
    Anti-Apolipoprotein E Antibody

  • Calmodulin interacts with ATP binding cassette transporter A1 to protect from calpain-mediated degradation and upregulates high-density lipoprotein generation. 20395597

    To investigate the interaction of ATP-binding cassette transporter A1 (ABCA1) with calmodulin in relation to its calpain-mediated degradation because many calpain substrates bind calmodulin to regulate cellular functions.The activity of ABCA1 is regulated through proteolysis by calpain. An immunoprecipitation and glutathione S-transferase pull-down assay revealed that ABCA1 directly binds calmodulin in a Ca(2+)-dependent manner. The cytoplasmic loop of ABCA1 contains a typical calmodulin binding sequence of 1-5-8-14 motifs (1245 to 1257 amino acids). The peptide of this region showed binding to calmodulin, and deletion of the 1-5-8-14 motif abolished this interaction. This motif is located near the ABCA1 Pro-Glu-Ser-Thr sequence, and the presence of calmodulin/Ca(2+) protected the peptides from proteolysis by calpain. The knockdown of calmodulin by a specific small and interfering RNA increased the degradation of ABCA1 and decreased ABCA1 protein and apolipoprotein A-I-mediated lipid release. Surprisingly, calmodulin inhibitor W7 increased calmodulin binding to ABCA1 and protected it from calpain-mediated degradation, consistent with our previous finding that this compound increased apolipoprotein A-I-mediated cell cholesterol release.Calmodulin directly binds and stabilizes ABCA1 in the presence of Ca(2+) and increases the generation of high-density lipoprotein.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MABN893
    Nombre del producto:
    Anti-ABCA1 Antibody, clone MABI98-7

  • Atorvastatin inhibits ABCA1 expression and cholesterol efflux in THP-1 macrophages by an LXR-dependent pathway. 18427282

    The effect of atorvastatin on adenosine triphosphate (ATP)-binding cassette transporter A1 (ABCA1) expression and cholesterol efflux remains controversial. In an effort to clarify this issue, ABCA1 expression and apolipoprotein AI (apoAI)-mediated cholesterol efflux after atorvastatin treatment were investigated in THP-1 macrophages. Atorvastatin from 2 microM to 40 microM dose-dependently inhibited ABCA1 expression in human monocyte-derived macrophages and phorbol 12-myristate 13-acetate (PMA)-stimulated THP-1 monocytes. ApoAI-mediated cholesterol efflux was reduced in PMA-stimulated THP-1 cells treated with atorvastatin, this effect was abolished with acetylated low-density lipoprotein (LDL) pretreatment. Atorvastatin treatment also dose-dependently reduced liver X receptor alpha (LXRalpha) expression and Rho activation. Rho activation by farnysylpyophosphate (FPP) and lysophosphatidic acid (LPA) did not salvage, but further depressed, the cholesterol efflux and ABCA1 expression in the presence of atorvastatin. Without atorvastatin, Rho activation by mevalonate, FPP, and LPA diminished apoAI-mediated cholesterol efflux, and Rho activation by GTPgammaS also decreased ABCA1 messenger ribonucleic acid (mRNA) by 16%. Furthermore, Rho inhibition by C3 exoenzyme increased ABCA1 mRNA by 48% despite a 17% decrease in apoAI-mediated cholesterol efflux. LXRalpha agonists (T01901317 and 22(R)-hydroxycholesterol) prevented any reductions in cholesterol efflux or ABCA1 expression associated with atorvastatin treatment. Furthermore, Western blot analysis demonstrated the reciprocal inhibition of Rho and LXRalpha. In conclusion, atorvastatin decreases ABCA1 expression in noncholesterol-loaded macrophages in an LXRalpha- but not Rho-dependent pathway; this effect can be compromised after acetylated LDL cholesterol loading.
    Tipo de documento:
    Referencia
    Referencia del producto:
    05-778
    Nombre del producto:
    Anti-Rho (-A Antibody, -B, -C), clone 55

  • Cyclin A1-deficient mice lack histone H3 serine 10 phosphorylation and exhibit altered aurora B dynamics in late prophase of male meiosis. 17498682

    Male mice lacking cyclin A1 protein are sterile. Their sterility results from an arrest in the meiotic cell cycle of spermatocytes, which we now identify as occurring at late diplotene, immediately before diakinesis. The stage of arrest in cyclin A1-deficient mice is distinct from the arrest seen in spermatocytes that are deficient in its putative catalytic partner Cdk2, which occurs much earlier in pachytene. The arrest in cyclin A1-deficient spermatocytes is also accompanied by an unusual clustering of centromeric heterochromatin. Consistent with a possible defect in the centromeric region, immunofluorescent staining of cyclin A1 protein shows localization in the region of the centromere. Phosphorylation of histone H3 at serine 10 in pericentromeric heterochromatin, which normally occurs in late diplotene, is reduced in spermatocytes from heterozygous Ccna1(+/-) testes and completely absent in spermatocytes with no cyclin A1 protein. Concomitantly, the levels of pericentromeric aurora B kinase, known to phosphorylate histone H3 during meiosis, are partially reduced in spermatocytes from testes of heterozygous mice and further reduced in homozygous null spermatocytes. These data suggest a critical and concentration-dependent function for cyclin A1 in the pericentromeric region in late diplotene of meiosis, perhaps in assembly or function of the passenger protein complex.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Targeting heterogeneous nuclear ribonucleoparticule A1 and A2 proteins by RNA interference promotes cell death in transformed but not in normal mouse cell lines. 15486185

    The heterogeneous nuclear ribonucleoparticule A1 and A2 proteins can bind to vertebrate single-stranded telomeric sequences. Moreover, changes in the levels of heterogeneous nuclear ribonucleoparticule A1 can influence telomere length in mouse and human cells. We have shown previously that the combined knockdown of A1 and A2 proteins in human transformed cells promotes apoptosis. In contrast, a similar reduction in A1 and A2 expression in normal mortal human cell lines does not induce cell death. Here, we show that a variety of mouse cell lines display a similar behavior on reduction of A1 and A2 protein levels using small interfering RNA. In addition, the expression of the mouse A1 cDNA protects human HeLa cells from apoptosis when human A1 and A2 proteins are targeted by RNA interference. Lastly, we show that knockdown of A1 and A2 expression also impairs the growth of a human transformed cell line that does not express telomerase. These results firmly establish A1 and A2 as proteins required for the viability of transformed murine and human cells, irrespective of the status of telomerase expression or the length of the double-stranded telomeric repeat.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AB3623
    Nombre del producto:
    Anti-Caspase 3 Antibody, active (cleaved) form

  • Different contribution of BH3-only proteins and caspases to doxorubicin-induced apoptosis in p53-deficient leukemia cells. 20188077

    Bcl-2 family proteins are key regulators of the intrinsic apoptotic pathway, either facilitating (Bax, Bak, BH3-only) or inhibiting (Bcl-2, Bcl-x(L), Mcl-1, A1) mitochondrial release of apoptogenic factors. The role of caspases in this process is a matter of controversy. We have analyzed the relative contribution of caspases and Bcl-2 family of proteins in the induction phase of apoptosis triggered by doxorubicin in two p53-deficient leukemia cell lines, Jurkat and U937. First, we have found that caspases are dispensable for the induction phase of doxorubicin-induced apoptosis in both cell lines but they are needed to speed up the execution phase in Jurkat cells, not expressing Bax. Thus, down-regulation of Bak expression by siRNA significantly prevented doxorubicin-induced apoptosis in Jurkat but not in U937 cells. Reduction of Mcl-1 protein levels with siRNA increased sensitivity to apoptosis in both cell lines. Moreover, our results indicate that the contribution of BH3-only proteins to apoptosis is cell line specific. In Jurkat cells simultaneous silencing of Bim and PUMA was necessary to reduce doxorubicin-induced apoptosis. In U937 cells silencing of Bim or Noxa reduced sensitivity to doxorubicin. Immunoprecipitation experiments discarded an interaction between Mcl-1 and Bak in both cell lines and underscored the role of Bim and PUMA as mediators of Bax/Bak activation.
    Tipo de documento:
    Referencia
    Referencia del producto:
    06-536
    Nombre del producto:
    Anti-Bak Antibody, NT

  • Orexin neurons of the hypothalamus express adenosine A1 receptors. 12106679

    Adenosine is a putative sleep factor with effects mainly mediated by the A1 receptor. Recent studies have implicated the hypothalamic orexin/hypocretin-containing neurons in the control of sleep-wakefulness. To help determine if adenosine might play a role in the control of orexin neurons, immunohistochemistry was used to characterize the distribution of adenosine A1 receptor protein on the orexinergic neurons. About 30% of orexin-containing neurons were labeled. The data supports the presence of adenosine A1 receptors on orexinergic neurons and suggests a possible substrate for a functional role of adenosine in the regulation of orexinergic activity.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AB1587P
    Nombre del producto:
    Anti-Adenosine A1 Receptor Antibody

  • Two-stage AMPA receptor trafficking in classical conditioning and selective role for glutamate receptor subunit 4 (tGluA4) flop splice variant. 22490558

    Previously, we proposed a two-stage model for an in vitro neural correlate of eyeblink classical conditioning involving the initial synaptic incorporation of glutamate receptor A1 (GluA1)-containing α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid type receptors (AMPARs) followed by delivery of GluA4-containing AMPARs that support acquisition of conditioned responses. To test specific elements of our model for conditioning, selective knockdown of GluA4 AMPAR subunits was used using small-interfering RNAs (siRNAs). Recently, we sequenced and characterized the GluA4 subunit and its splice variants from pond turtles, Trachemys scripta elegans (tGluA4). Analysis of the relative abundance of mRNA expression by real-time RT-PCR showed that the flip/flop variants of tGluA4, tGluA4c, and a novel truncated variant tGluA4trc1 are major isoforms in the turtle brain. Here, transfection of in vitro brain stem preparations with anti-tGluA4 siRNA suppressed conditioning, tGluA4 mRNA and protein expression, and synaptic delivery of tGluA4-containing AMPARs but not tGluA1 subunits. Significantly, transfection of abducens motor neurons by nerve injections of tGluA4 flop rescue plasmid prior to anti-tGluA4 siRNA application restored conditioning and synaptic incorporation of tGluA4-containing AMPARs. In contrast, treatment with rescue plasmids for tGluA4 flip or tGluA4trc1 failed to rescue conditioning. Finally, treatment with a siRNA directed against GluA1 subunits inhibited conditioning and synaptic delivery of tGluA1-containing AMPARs and importantly, those containing tGluA4. These data strongly support our two-stage model of conditioning and our hypothesis that synaptic incorporation of tGluA4-containing AMPARs underlies the acquisition of in vitro classical conditioning. Furthermore, they suggest that tGluA4 flop may have a critical role in conditioning mechanisms compared with the other tGluA4 splice variants.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo