Integrating data mining within a strategic knowledge management framework: A platform for sustainable competitive advantage within the Australian Minerals and Metals Mining sector

<p>N = 4–10 mice.</p

Calcein accumulation in guinea pig primary brain endothelial cells (n = 6) presented as % of control with increasing doses of sertraline (SERT) and 10⁻⁴ of verapamil (VPL).

<p>Calcein accumulation was assessed at (A) 15 min, (B) 60 min, (C), 120 min and (D) 240 min. * indicates p<0.05 and ** indicates p<0.01 compared to control cells.</p

Accumulation of [3H] digoxin in FVB mice (n = 4–9) co-administered sertraline (10 mg/kg; closed bars) or saline (control; open bars).

<p>Mice were euthanized at various time points (1 m, 5 min, 15 min, 1 h, 4 h, 12 h, 24 h) and DPM measured in the testes, heart and plasma. All data is expressed as mean±SEM. (A) testes∶plasma DPM ratio, (B) heart∶plasma DPM ratio. * indicates p<0.05 vs. control. ** indicates p<0.01 vs. control.</p

P-gp function in GD50 BECs is unresponsive to pro-inflammatory cytokines.

<p>P-glycoprotein (P-gp) activity in brain endothelial cell (BEC) cultures derived from gestational day (GD) 50 male guinea pigs following treatment with 10⁰–10⁴ pg/mL A–C) interleukin-1β (IL-1β), D–F) interleukin-6 (IL-6) or G–I) tumor necrosis factor-α (TNF-α) for 1, 4 or 24 hours (N = 4). P-gp activity is displayed as percent change from untreated control cells (zero line). Values displayed as mean ± S.E.M.</p

Pro-inflammatory cytokines inhibit P-gp function in GD65 BECs in a dose-dependent manner.

<p>P-glycoprotein (P-gp) activity in brain endothelial cell (BEC) cultures derived from gestational day (GD) 65 male guinea pigs following treatment with 10⁰–10⁴ pg/mL A–C) interleukin-1β (IL-1β), D–F) interleukin-6 (IL-6) or G–I) tumor necrosis factor-α (TNF-α) for 1, 4 or 24 hours (N = 4). P-gp activity is displayed as percent change from untreated control cells (zero line). Values displayed as mean ± S.E.M. A significant difference from control indicated by (*) P<0.05; (**) P<0.01.</p

The inhibitory effects of pro-inflammatory cytokines on P-gp function are greatest in PND14 BECs.

<p>P-glycoprotein (P-gp) activity in brain endothelial cell (BEC) cultures derived from postnatal day (PND) 14 male guinea pigs following treatment with 10⁰–10⁴ pg/mL A–C) interleukin-1β (IL-1β), D–F) interleukin-6 (IL-6) or G–I) tumor necrosis factor-α (TNF-α) for 1, 4 or 24 hours (N = 8). P-gp activity is displayed as percent change from untreated control cells (zero line). Values displayed as mean ± S.E.M. A significant difference from control indicated by (*) P<0.05; (**) P<0.01.</p

Pro-inflammatory cytokines inhibit <i>abcb1</i> mRNA expression.

<p><i>Abcb1</i> mRNA expression in brain endothelial cell (BEC) cultures derived from postnatal day (PND) 14 male guinea pigs following treatment with 10³ and 3.3×10³ pg/mL A–B) interleukin-1β (IL-1β), C–D) interleukin-6 (IL-6) or E–F) tumor necrosis factor-α (TNF-α) for 4 (A,C,E) or 24 hours (B,D,F) (N = 7–8). Expression is displayed as percent of untreated control cell expression (i.e. 100% line) and taken over the reference gene, <i>beta-actin</i>. Values displayed as mean ± S.E.M. A significant difference from control indicated by (**) P<0.01; (***) P<0.001.</p

Baseline P-gp Activity in BECs increases with developmental age.

<p>P-glycoprotein (P-gp) activity in brain endothelial cell (BEC) cultures derived from gestational day (GD) 40, 50, 65 and postnatal day (PND) 14 male guinea pigs (N = 4). P-gp activity is displayed as percent change from GD40 BECs (zero line). P-gp function was calculated over relative cell count. Values displayed as mean ± S.E.M. A significant difference from GD40 indicated by (*) P<0.05; (***) P<0.001.</p

The inhibitory effects of pro-inflammatory cytokines are specific to P-gp and do not alter non-specific esterase activity.

<p>Postnatal day 14 male guinea pig BEC A) P-gp activity (using Rhodamine 123 as a P-gp substrate) following 24 hour treatment with 3.3×10³ pg/mL interleukin-1β (IL-1β), interleukin-6 (IL-6) or tumor necrosis factor-α (TNF-α) (N = 6); and B) non-specific esterase activity following 24 hour treatment with 3.3×10³ pg/mL IL-1β, IL-6 or TNF-α (N = 6). P-gp activity is displayed as percent change from untreated control cells (zero line). Values displayed as mean ± S.E.M. A significant difference from control indicated by (**) <i>P</i><0.01.</p

The Multidrug Resistance 1 Gene <i>Abcb1</i> in Brain and Placenta: Comparative Analysis in Human and Guinea Pig

<div><p>The Multidrug Resistance 1 (<i>MDR1;</i> alternatively <i>ABCB1</i>) gene product P-glycoprotein (P-gp), an ATP binding cassette transporter, extrudes multiple endogenous and exogenous substrates from the cell, playing an important role in normal physiology and xenobiotic distribution and bioavailability. To date, the predominant animal models used to investigate the role of P-gp have been the mouse and rat, which have two distinct genes, <i>Abcb1a</i> and <i>Abcb1b.</i> In contrast, the human has a single gene, <i>ABCB1,</i> for which only a single isoform has been validated. We and others have previously shown important differences between Abcb1a and Abcb1b, limiting the extrapolation from rodent findings to the human. Since the guinea pig has a relatively long gestation, hemomonochorial placentation and neuroanatomically mature offspring, it is more similar to the human, and may provide a more comparable model for investigating the regulation of P-gp in the brain and placenta, however, to date, the <i>Abcb1</i> gene in the guinea pig remains to be characterized. The placenta and fetal brain are barrier sites that express P-gp and that play a critical role of protection of the fetus and the fetal brain from maternally administered drugs and other xenobiotics. Using RNA sequencing (RNA-seq), reverse transcription-polymerase chain reaction (RT-PCR) and quantitative PCR (QPCR) to sequence the expressed isoforms of guinea pig <i>Abcb1</i>, we demonstrate that like the human, the guinea pig genome contains one gene for <i>Abcb1</i> but that it is expressed as at least three different isoforms via alternative splicing and alternate exon usage. Further, we demonstrate that these isoforms are more closely related to human than to rat or mouse isoforms. This striking, overall similarity and evolutionary relatedness between guinea pig <i>Abcb1</i> and human <i>ABCB1</i> indicate that the guinea pig represents a relevant animal model for investigating the function and regulation of P-gp in the placenta and brain.</p></div