The deposition of ␤-amyloid in the brain is a pathological hallmark of Alzheimer disease (AD). Normally, the accumulation of ␤-amyloid is prevented in part by the activities of several degradative enzymes, including the endothelin-converting enzymes, neprilysin, insulin-degrading enzyme, and plasmin. Recent reports indicate that another metalloprotease, angiotensin-converting enzyme (ACE), can degrade ␤-amyloid in vitro and in cellular overexpression experiments. In addition, ACE gene variants are linked to AD risk in several populations. Angiotensin-converting enzyme, neprilysin and endothelin-converting enzyme function as vasopeptidases and are the targets of drugs designed to treat cardiovascular disorders, and ACE inhibitors are commonly prescribed. We investigated the potential physiological role of ACE in regulating endogenous brain ␤-amyloid levels for two reasons: first, to determine whether ␤-amyloid degradation might be the mechanism by which ACE is associated with AD, and second, to determine whether ACE inhibitor drugs might block ␤-amyloid degradation in the brain and potentially increase the risk for AD. We analyzed ␤-amyloid accumulation in brains from ACE-deficient mice and in mice treated with ACE inhibitors and found that ACE deficiency did not alter steady-state ␤-amyloid concentration. In contrast, ␤-amyloid levels are significantly elevated in endothelin-converting enzyme and neprilysin knock-out mice, and inhibitors of these enzymes cause a rapid increase in ␤-amyloid concentration in the brain. The results of these studies do not support a physiological role for ACE in the degradation of ␤-amyloid in the brain but confirm roles for endothelin-converting enzyme and neprilysin and indicate that reductions in these enzymes result in additive increases in brain amyloid ␤-peptide levels.

Journal of the American Society for Mass Spectrometry 10 (1999) 1315-1321. doi:10.1016/S1044-0305(99)00103-82016-03-04T18:48:28

Globoid cell leukodystrophy (GLD) or Krabbe disease is a devastating, degenerative neurological disorder caused by mutations in the galactosylceramidase (GALC) gene that severely affect enzyme activity. Currently, treatment options for this disorder are very limited. Enzyme replacement therapy (ERT) has been shown to be effective in lysosomal storage disorders with predominantly peripheral manifestations such as type I Gaucher's and Fabry's disease. Little however is known about the possible benefit of ERT in GLD, which has a substantial central nervous system component. In this study, we examined the effect of peripheral GALC injections in the twitcher mouse model of the disease. Although we were unable to block the precipitous decline that normally occurs just before death, we did observe significant early improvements in motor performance, a substantial attenuation in the initial failure to thrive, and an increase in life span. Immunohistochemical and activity analyses demonstrated GALC uptake in multiple tissues, including the brain. This was associated with a decrease in the abnormal accumulation of the GALC substrate psychosine, which is thought to play a pivotal role in disease pathology. These results indicate that peripheral ERT is likely to be beneficial in GLD.

Globoid cell leukodystrophy (GLD), also known as Krabbe disease, is a devastating, degenerative neurological disorder. It is inherited as an autosomal recessive trait caused by loss-of-function mutations in the galactocerebrosidase (GALC) gene. Previously, we have shown that peripheral injection of recombinant GALC, administered every other day, results in a substantial improvement in early clinical phenotype in the twitcher mouse model of GLD. While we did detect active enzyme in the brain following peripheral administration, most of the administered enzyme was localized to the periphery. Given the substantial central nervous system (CNS) involvement in this disease, we were interested in determining whether or not a single-dose administration of the recombinant enzyme directly to the CNS, which could potentially be achieved clinically, would result in any substantial improvement. Following intracerebroventricular (i.c.v.) administration of GALC we noted a significant, 16.5%, reduction in the GALC substrate psychosine, the abnormal accumulation of which is believed to play a pivotal role in the CNS pathology observed in this disease. Moreover, recombinant GALC was found not only in periventricular regions but also at sites distant to the injection such as the cerebral cortex and cerebellum. Most importantly, animals receiving a single i.c.v. dose of the enzyme at postnatal day 20 survived up to 51 days, which compares favorably to the control twitcher animals, which normally only live to postnatal day 40/42. These results indicate that even a single i.c.v. administration of the recombinant enzyme can have significant clinical impact and suggests that other lysosomal storage disorders with significant CNS involvement may similarly benefit.

In a continuing search for curcuminoid (CUR) compounds with antitumor activity, a novel series of heterocyclic CUR-BF adducts and CUR compounds based on indole, benzothiophene, and benzofuran along with their aryl pyrazoles were synthesized. Computational docking studies were performed to compare binding efficiency to target proteins involved in specific cancers, namely HER2, proteasome, VEGFR, BRAF, and Bcl-2, versus known inhibitor drugs. The majority presented very good binding affinities, similar to, and even more favorable than those of known inhibitors. The indole-based CUR-BF and CUR compounds and their bis-thiocyanato derivatives exhibited high anti-proliferative and apoptotic activity by in vitro bioassays against a panel of 60 cancer cell lines, more specifically against multiple myeloma (MM) cell lines (KMS11, MM1.S, and RPMI-8226) with significantly lower IC values versus healthy PBMC cells; they also exhibited higher anti-proliferative activity in human colorectal cancer cells (HCT116, HT29, DLD-1, RKO, SW837, and Caco2) than the parent curcumin, while showing notably lower cytotoxicity in normal colon cells (CCD112CoN and CCD841CoN).

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The Front Cover shows the microscope slides of colorectal cancer cells (DLD‐1) treated with two new indole‐based heterocyclic curcuminoids bearing SCN substituents [3‐thiocyanato‐indole‐5‐curcuminoid–BF2 adduct (4‐BF2) on the left and (1E,4E,6E)‐5‐hydroxy‐1,7‐bis(3‐thiocyanoindole‐4)hepta‐1,4,6‐trien‐3‐one (5) on right] at 10 μM concentrations for 24 h. For comparison, the center slide shows cells treated with DMSO alone (control) for 24 h. Heterocyclic CUR‐BF2 compounds, such as indole‐4‐curcuminoid‐BF2 adduct (3‐BF2) shown in the center pose, exhibit favorable docking ability into Bcl‐2. Hydrophobic contacts between the atoms of the ligand and protein residues are the principle interactions involved, along with hydrogen bond interactions between F and N ligand atoms and hydrogen bond donor groups in neighboring protein residues. The DFT‐optimized structures of two remarkably active bis‐SCN‐substituted CUR‐BF2 compounds are displayed as well. Unlike the very distinct yellow color of curcumin itself, these new heterocyclic analogs have distinctly different colors. More information can be found in the Full Paper by Kenneth K. Laali et al. on page 1895 in Issue 18, 2018 (DOI: 10.1002/cmdc.201800320).