Disrupting the Conserved Salt Bridge in the Trimerization of Influenza A Nucleoprotein.

Antiviral drug resistance in influenza infections has been a major threat to public health. To develop a broad-spectrum inhibitor of influenza to combat the problem of drug resistance, we previously identified the highly conserved E339...R416 salt bridge of the nucleoprotein trimer as a target and compound 1 as an inhibitor disrupting the salt bridge with an EC50 = 2.7 µM against influenza A (A/WSN/1933). We have further modified this compound via a structure-based approach and performed antiviral activity screening to identify compounds 29 and 30 with EC50 values of 110 and 120 nM, respectively, and without measurable host cell cytotoxicity. Compared to the clinically used neuraminidase inhibitors, these two compounds showed better activity profiles against drug-resistant influenza A strains, as well as influenza B, and improved survival of influenza-infected mice.

Influenza A surface glycosylation and vaccine design.

We have shown that glycosylation of influenza A virus (IAV) hemagglutinin (HA), especially at position N-27, is crucial for HA folding and virus survival. However, it is not known whether the glycosylation of HA and the other two major IAV surface glycoproteins, neuraminidase (NA) and M2 ion channel, is essential for the replication of IAV. Here, we show that glycosylation of HA at N-142 modulates virus infectivity and host immune response. Glycosylation of NA in the stalk region affects its structure, activity, and specificity, thereby modulating virus release and virulence, and glycosylation at the catalytic domain affects its thermostability; however, glycosylation of M2 had no effect on its function. In addition, using IAV without the stalk and catalytic domains of NA as a live attenuated vaccine was shown to confer a strong IAV-specific CD8+ T-cell response and a strong cross-strain as well as cross-subtype protection against various virus strains.

Dual Targeting of 3-Hydroxy-3-methylglutaryl Coenzyme A Reductase and Histone Deacetylase as a Therapy for Colorectal Cancer.

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (HMGR) inhibitors decreasing serum cholesterol and have shown promise in cancer prevention. In this study, we demonstrated the oncogenic role of HMGR in colorectal cancer (CRC) by disclosing increased HMGR activity in CRC patients and its enhancement of anti-apoptosis and stemness. Our previous studies showed that statins containing carboxylic acid chains possessed activity against histone deacetylases (HDACs), and strengthened their anti-HDAC activity through designing HMGR-HDAC dual inhibitors, JMF compounds. These compounds exerted anti-cancer effect in CRC cells as well as in AOM-DSS and Apc(Min/+) CRC mouse models. JMF mostly regulated the genes related to apoptosis and inflammation through genome-wide ChIP-on-chip analysis, and Ingenuity Pathways Analysis (IPA) predicted their respective regulation by NR3C1 and NF-κB. Furthermore, JMF inhibited metastasis, angiogenesis and cancer stemness, and potentiated the effect of oxaliplatin in CRC mouse models. Dual HMGR-HDAC inhibitor could be a potential treatment for CRC.

Design and synthesis of dual-action inhibitors targeting histone deacetylases and 3-hydroxy-3-methylglutaryl coenzyme A reductase for cancer treatment.

A series of dual-action compounds were designed to target histone deacetylase (HDAC) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) by having a hydroxamate group essential for chelation with the zinc ion in the active site of HDAC and the key structural elements of statin for binding with both proteins. In our study, the statin hydroxamic acids prepared by a fused strategy are most promising in cancer treatments. These compounds showed potent inhibitory activities against HDACs and HMGR with IC50 values in the nanomolar range. These compounds also effectively reduced the HMGR activity as well as promoted the acetylations of histone and tubulin in cancer cells, but were not toxic to normal cells.

Design and synthesis of novel dual-action compounds targeting the adenosine A(2A) receptor and adenosine transporter for neuroprotection.

A novel compound, N6-(4-hydroxybenzyl)adenosine, isolated from Gastrodia elata and which has been shown to be a potential therapeutic agent for preventing and treating neurodegenerative disease, was found to target both the adenosine A(2A) receptor (A(2A) R) and the equilibrative nucleoside transporter 1 (ENT1). As A(2A) R and ENT1 are proximal in the synaptic crevice of striatum, where the mutant huntingtin aggregate is located, the dual-action compounds that concomitantly target these two membrane proteins may be beneficial for the therapy of Huntington's disease. To design the desired dual-action compounds, pharmacophore models of the A(2A) R agonists and the ENT1 inhibitors were constructed. Accordingly, potentially active compounds were designed and synthesized by chemical modification of adenosine, particularly at the N6 and C5' positions, if the predicted activity was within an acceptable range. Indeed, some of the designed compounds exhibit significant dual-action properties toward both A(2A) R and ENT1. Both pharmacophore models exhibit good statistical correlation between predicted and measured activities. In agreement with competitive ligand binding assay results, these compounds also prevent apoptosis in serum-deprived PC12 cells, rendering a crucial function in neuroprotection and potential utility in the treatment of neurodegenerative diseases.

A new drug design targeting the adenosinergic system for Huntington's disease.

BACKGROUND: Huntington's disease (HD) is a neurodegenerative disease caused by a CAG trinucleotide expansion in the Huntingtin (Htt) gene. The expanded CAG repeats are translated into polyglutamine (polyQ), causing aberrant functions as well as aggregate formation of mutant Htt. Effective treatments for HD are yet to be developed. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report a novel dual-function compound, N(6)-(4-hydroxybenzyl)adenine riboside (designated T1-11) which activates the A(2A)R and a major adenosine transporter (ENT1). T1-11 was originally isolated from a Chinese medicinal herb. Molecular modeling analyses showed that T1-11 binds to the adenosine pockets of the A(2A)R and ENT1. Introduction of T1-11 into the striatum significantly enhanced the level of striatal adenosine as determined by a microdialysis technique, demonstrating that T1-11 inhibited adenosine uptake in vivo. A single intraperitoneal injection of T1-11 in wildtype mice, but not in A(2A)R knockout mice, increased cAMP level in the brain. Thus, T1-11 enters the brain and elevates cAMP via activation of the A(2A)R in vivo. Most importantly, addition of T1-11 (0.05 mg/ml) to the drinking water of a transgenic mouse model of HD (R6/2) ameliorated the progressive deterioration in motor coordination, reduced the formation of striatal Htt aggregates, elevated proteasome activity, and increased the level of an important neurotrophic factor (brain derived neurotrophic factor) in the brain. These results demonstrate the therapeutic potential of T1-11 for treating HD. CONCLUSIONS/SIGNIFICANCE: The dual functions of T1-11 enable T1-11 to effectively activate the adenosinergic system and subsequently delay the progression of HD. This is a novel therapeutic strategy for HD. Similar dual-function drugs aimed at a particular neurotransmitter system as proposed herein may be applicable to other neurotransmitter systems (e.g., the dopamine receptor/dopamine transporter and the serotonin receptor/serotonin transporter) and may facilitate the development of new drugs for other neurodegenerative diseases.