Effect of APOE ε4 Genotype on Metabolic Biomarkers in Aging and Alzheimer's Disease.

Alzheimer's disease (AD) may have heterogeneous pathophysiological underpinnings, with risk factors including apolipoprotein rmvarep4 (APOE4) genotype and insulin resistance. We hypothesized that distinct phenotypes exist within AD. We examined APOE4 and metabolic biomarkers in 338 subjects (n = 213 nondemented (ND), n = 125 AD). We further characterized steady state free fatty acid (FFA) levels in a subset of 45 participants who had also participated in a hyperinsulinemic-euglycemic clamp. Insulin resistance (HOMA-IR) was elevated in AD versus ND (p = 0.04) and in APOE4 noncarriers versus carriers (p < 0.01). This was driven by increased fasting insulin in AD versus ND (p < 0.01) and in APOE4 non-carriers versus carriers (p = 0.01). Fasting glucose was not different. In subjects who underwent a clamp, there was a group x genotype interaction on FFA levels during hyperinsulinemia (p = 0.03). APOE4 non-carriers with AD had higher FFA levels, while APOE4 carriers with AD exhibited lower FFA levels. Metabolic dysfunction is overrepresented in individuals with AD dementia who do not carry the APOE4 allele. This suggests that important subsets of AD phenotypes may exist that diverge metabolically.

Structure-guided design and optimization of dipeptidyl inhibitors of norovirus 3CL protease. Structure-activity relationships and biochemical, X-ray crystallographic, cell-based, and in vivo studies.

Norovirus infection constitutes the primary cause of acute viral gastroenteritis. There are currently no vaccines or norovirus-specific antiviral therapeutics available for the management of norovirus infection. Norovirus 3C-like protease is essential for viral replication, consequently, inhibition of this enzyme is a fruitful avenue of investigation that may lead to the emergence of antinorovirus therapeutics. We describe herein the optimization of dipeptidyl inhibitors of norovirus 3C-like protease using iterative SAR, X-ray crystallographic, and enzyme and cell-based studies. We also demonstrate herein in vivo efficacy of an inhibitor using the murine model of norovirus infection.

Design, synthesis, and bioevaluation of viral 3C and 3C-like protease inhibitors.

A class of tripeptidyl transition state inhibitors containing a P1 glutamine surrogate, a P2 leucine, and a P3 arylalanines, was found to potently inhibit Norwalk virus replication in enzyme and cell based assays. An array of warheads, including aldehyde, α-ketoamide, bisulfite adduct, and α-hydroxyphosphonate transition state mimic, was also investigated. Tripeptidyls 2 and 6 possess antiviral activities against noroviruses, human rhinovirus, severe acute respiratory syndrome coronavirus, and coronavirus 229E, suggesting a broad range of antiviral activities.

Potent inhibition of norovirus by dipeptidyl α-hydroxyphosphonate transition state mimics.

The design, synthesis, and evaluation of a series of dipeptidyl α-hydroxyphosphonates is reported. The synthesized compounds displayed high anti-norovirus activity in a cell-based replicon system, as well as high enzyme selectivity.

Macrocyclic inhibitors of 3C and 3C-like proteases of picornavirus, norovirus, and coronavirus.

The design, synthesis, and in vitro evaluation of the first macrocyclic inhibitor of 3C and 3C-like proteases of picornavirus, norovirus, and coronavirus are reported. The in vitro inhibitory activity (50% effective concentration) of the macrocyclic inhibitor toward enterovirus 3C protease (CVB3 Nancy strain), and coronavirus (SARS-CoV) and norovirus 3C-like proteases, was determined to be 1.8, 15.5 and 5.1 µM, respectively.

Inhibition of norovirus 3CL protease by bisulfite adducts of transition state inhibitors.

Noroviruses are the most common cause of acute viral gastroenteritis, accounting for >21 million cases annually in the US alone. Norovirus infections constitute an important health problem for which there are no specific antiviral therapeutics or vaccines. In this study, a series of bisulfite adducts derived from representative transition state inhibitors (dipeptidyl aldehydes and α-ketoamides) was synthesized and shown to exhibit anti-norovirus activity in a cell-based replicon system. The ED(50) of the most effective inhibitor was 60 nM. This study demonstrates for the first time the utilization of bisulfite adducts of transition state inhibitors in the inhibition of norovirus 3C-like protease in vitro and in a cell-based replicon system. The approach described herein can be extended to the synthesis of the bisulfite adducts of other classes of transition state inhibitors of serine and cysteine proteases, such as α-ketoheterocycles and α-ketoesters.