J. Lazarte

A liposome-based therapeutic vaccine against β-amyloid plaques on the pancreas of transgenic NORBA mice

Immune tolerance to β-amyloid (Aβ) was broken in NORBA transgenic mice presenting Aβ plaques on their pancreases. Vaccination of Black C57, BALB/c, and NORBA mice with the synthetic Aβ1–16 sequence modified by covalently attaching two palmitoyl residues at each end of the peptide, subsequently reconstituted in liposomes–Lipid A elicited titers of 1:5,000 of anti-Aβ1–16 antibodies within 10 weeks after the first inoculation. On direct interaction, sera with antibody titers of 1:5,000 solubilized in vitro up to 80% of preformed Aβ1–42 aggregates. Cryosections of pancreases of unvaccinated NORBA mice show, on staining with Thioflavin T, extensive areas of high-intensity fluorescence in the acinar cell fields. Quantitation of the average fluorescence intensity in each section indicated that: (i) whereas nonvaccinated NORBA mice develop plaques within 45–60 days after birth, vaccinated 8-week-old NORBA mice did not develop amyloid plaques on their pancreases over a period of 7 months; (ii) cryosections from pancreases of 9- and 15-month-old vaccinated NORBA mice showed less than 50% of the fluorescence shown by cryosections from unvaccinated animals of the same age. The results indicate that palmitoylated Aβ peptides, reconstituted in liposomes–lipid A, are highly immunogenic, eliciting “therapeutic” antibody titers within 3 months of the first inoculation and preventing amyloid plaque formation in young animals or significantly reducing existing plaques in older transgenic mice. Possible implications for the therapy of Alzheimers disease are discussed.

TERT-BUTYLHYDROQUINONE RESCUES CYCLOSPORINE-A MEDIATED IMPAIRMENT IN VASCULAR FUNCTION VIA AUGMENTING PHOSPHORYLATION OF THE TRANSCRIPTION FACTOR NRF2

Background: Oxidative stress mediates cyclosporine-A (CsA) associated vascular injury post-cardiac transplantation. We investigated the effect of CsA on the Nrf2 pathway by examining vascular function, Nrf2 phosphorylation and superoxide dismutase (SOD) activity and the ability of tBHQ to rescue CsA-mediated injury. Methods and Results: Lewis rats received tBHQ (50mg/kg), CsA (5mg/kg) ± tBHQ, or Saline (CON). Thoracic aortic segments were assessed for vascular function as measured by endothelial-dependent (Edep) relaxation (ED50), and sensitivity to endothelin-1 (ET-1) vasoconstriction. We also analyzed Nrf2 protein expression, phospho-Nrf2/Nrf2 ratio, and SOD activity. CsA significantly impaired Edep vasorelaxation (ED50: 3.5x10-8 +/- 0.4M vs CON 1.8x10-8 +/- 0.5M, p<0.001). tBHQ did not affect vasorelaxation compared to CON (2.18x10-8 +/- 0.4M, p=NS). However, tBHQ improved vasorelaxation in CsA-treated rats significantly (ED50: 2.69x10-8 +/- 0.3M vs CsA alone, p<0.001). Compared to CON, CsA exposure demonstrated increased sensitivity to ET-1 vasospasm (CsA ED50 1.9x10-9 +/- 0.1M vs 2.85x10-9 +/- 0.4M CON, p<0.001) which was rescued significantly by tBHQ exposure compared to CsA alone (ED50: 2.55x10-9 +/- 0.5M). tBHQ alone did not affect sensitivity to ET-1 vasospasm compared to CON (ED50: 2.65x10-9 +/- 0.3M, p=NS). CsA treatment resulted in decreased Nrf2 expression, phosphorylation, and SOD activity (Fig1). Exposure to tBHQ rescued CsA-mediated Nrf2 downregulation, and reduction in Nrf2 phosphorylation and SOD activity (Fig1). Conclusions: Our study suggests potential therapeutic strategies to prevent coronary vascular dysfunction as combined therapy with tBHQ completely abrogated CsA-induced impairment of Nrf2- signalling and vascular injury. Mechanistically, tBHQ may act to rescue Nrf2 expression, phosphorylation and SOD activity in order to ameliorate CsA-mediated coronary dysfunction. ![][1] [1]: /embed/graphic-1.gif