Brain Protection Conferred by Long-Term Administration of 2-(2-Benzofuranyl)-2-Imidazoline Against Experimental Autoimmune Encephalomyelitis
NEUROCHEMICAL RESEARCH
Authors: Zhu, Ying-Biao; Xia, Nian-Ge; Zhang, Yuan-Tao; Wang, Xin-Shi; Liang, Shan-Shan; Yin, Wei-Yong; Xu, Hui-Qin; Hou, Sheng-Tao; Zheng, Rong-Yuan
Abstract
Our previous studies showed that 2-(2-benzofuranyl)-2-imidazoline (2-BFI), a ligand to type 2 imidazoline receptor, was protective against brain and spinal cord injury caused by experimental autoimmune encephalomyelitis (EAE). In the present study, we investigated the effect of long-term administration of 2-BFI and the dose-dependent response relationship of long-term administration of 2-BFI with neuroprotection. Treatment with 2-BFI at doses of 5, 10, and 20 mg/kg for 14 days significantly reduced hind limb paralysis and the severity of EAE compared with the EAE control group. Long-term use of 2-BFI was not only safe to mice, but also dose-dependently reduced the expression of inflammatory cytokines, including TNF-alpha, Interferon-gamma and Interleukin-17A, compared with the EAE control group. Expressions of neuronal injury markers, including cytochrome c, AIF and beta-APP, were also reduced significantly in response to long-term 2-BFI treatment. Together, these results provided new evidence to demonstrate that 2-BFI is a safe and effective candidate for further development as a therapeutic drug for treatment of multiple sclerosis.
Aminopeptidase A contributes to the N-terminal truncation of amyloid beta-peptide
JOURNAL OF NEUROCHEMISTRY
Authors: Sevalle, Jean; Amoyel, Audrey; Robert, Philippe; Fournie-Zaluski, Marie-Claude; Roques, Bernard; Checler, Frederic
Abstract
Several lines of data previously indicated that N-terminally truncated forms of amyloid-beta (A beta) peptides are likely the earliest and more abundant species immunohistochemically detectable in Alzheimer's disease-affected brains. It is noteworthy that the free N-terminal residue of full-length A beta (fl-A beta) is an aspartyl residue, suggesting that A beta could be susceptible to exopeptidasic attack by aminopeptidase A (APA)-like proteases. In this context, we have examined whether APA could target A beta peptides in both cell-free and cellular models. We first show that the general aminopeptidase inhibitor amastatin as well as two distinct aminopeptidase A inhibitors EC33 and pl302 both significantly increase the recovery of genuine fl-A beta peptides generated by cells over-expressing Swedish-mutated beta amyloid precursor protein (APP) while the aminopeptidase N blocker pl250 did not modify fl-A beta recovery. In agreement with this observation, we establish that over-expressed APA drastically reduces, in a calcium dependent manner, fl-A beta but not APP IntraCellular Domain in a cell-free model of A beta production. In agreement with the above data, we show that recombinant APA degrades fl-A beta in a pl302-sensitive manner. Interestingly, we also show that EC33 and pl302 lower staurosporine-stimulated activation of caspase-3 in wild-type fibroblasts but not in beta APP/beta-amyloid precursor protein-like protein 2 (APLP2) double knockout fibroblasts, suggesting that protecting endogenous fl-A beta physiological production triggers neuroprotective phenotype. By contrast, EC33 does not modify staurosporine-induced caspase-3 activation in wild-type and Swedish-mutated beta APP-HEK293 expressing cells that display exacerbated production of A beta. Overall, our data establish that APA contributes to the N-terminal truncation of A beta and suggest that this cleavage is likely abrogating a protective function associated with physiological but not supraphysiological levels of genuine fl-A beta peptides.