3-Pyridinylboronic Acid Ameliorates Rotenone-Induced Oxidative Stress Through Nrf2 Target Genes in Zebrafish Embryos.

Parkinson's disease (PD) is one of the most common forms of neurodegenerative diseases and research on potential therapeutic agents for PD continues. Rotenone is a neurotoxin that can pass the blood-brain barrier and is used to generate PD models in experimental animals. Boron is a microelement necessary for neural activity in the brain. Antioxidant, non-cytotoxic, anti-genotoxic, anti-carcinogenic effects of boric acid, the salt compound of boron has been reported before. Boronic acids have been approved for treatment by FDA and are included in drug discovery studies and pyridine boronic acids are a subclass of heterocyclic boronic acids used in drug design and discovery as substituted pyridines based on crystal engineering principles. The aim of our study was to determine the effect of 3-pyridinylboronic acid in rotenone-exposed zebrafish embryos, focusing on oxidant-antioxidant parameters and gene expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) target genes gclm, gclc, hmox1a, nqo1, and PD related genes, brain-derived neurotrophic factor, dj1, and tnfα. Zebrafish embryos were exposed to Rotenone (10 µg/l); Low Dose 3-Pyridinylboronic acid (100 µM); High Dose 3-Pyridinylboronic acid (200 µM); Rotenone + Low Dose-3-Pyridinylboronic acid (10 µg/l + 100 µM); Rotenone + High Dose-3-Pyridinylboronic acid (10 µg/l + 200 µM) in well plates for 96 h post-fertilization (hpf). Our study showed for the first time that 3-pyridinylboronic acid, as a novel sub-class of the heterocyclic boronic acid compound, improved locomotor activities, ameliorated oxidant-antioxidant status by decreasing LPO and NO levels, and normalized the expressions of bdnf, dj1, tnf⍺ and Nrf2 target genes hmox1a and nqo1 in rotenone exposed zebrafish embryos. On the other hand, it caused the deterioration of the oxidant-antioxidant balance in the control group through increased lipid peroxidation, nitric oxide levels, and decreased antioxidant enzymes. We believe that these results should be interpreted in the context of the dose-toxicity and benefit-harm relationship of the effects of 3-pyridinylboronic.

3-Pyridinylboronic acid normalizes the effects of 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine exposure in zebrafish embryos.

1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin that damages dopaminergic neurons. Zebrafish has been shown to be a suitable model organism to investigate the molecular pathways in the pathogenesis of Parkinson's disease and also for potential therapeutic agent research. Boron has been shown to play an important role in the neural activity of the brain. Boronic acids are used in combinatorial approaches in drug design and discovery. The effect of 3-pyridinylboronic acid which is an important sub-class of heterocyclic boronic acids has not been evaluated in case of MPTP exposure in zebrafish embryos. Accordingly, this study was designed to investigate the effects of 3-pyridinylboronic acid on MPTP exposed zebrafish embryos focusing on the molecular pathways related to neurodegeneration and apoptosis by RT-PCR. Zebrafish embryos were exposed to MPTP (800 µM); MPTP + Low Dose 3-Pyridinylboronic acid (50 µM) (MPTP + LB) and MPTP + High Dose 3-Pyridinylboronic acid (100 µM) (MPTP + HB) in well plates for 72 hours post fertilization. Results of our study showed that MPTP induced a P53 dependent and Bax mediated apoptosis in zebrafish embryos and 3-pyridinylboronic acid restored the locomotor activity and gene expressions related to mitochondrial dysfunction and oxidative stress due to the deleterious effects of MPTP, in a dose-dependent manner.

Targeting sialic acid residues on lung cancer cells by inhalable boronic acid-decorated albumin nanocomposites for combined chemo/herbal therapy.

Etoposide (ETP), as a potential treatment for lung cancer, has limited application due to its poor solubility, and systemic side effects. In the current study, we propose inhalable boronate-targeted HSA nanocomposites for combined delivery of ETP and the herbal drug, berberine (BER) for localized therapy of lung cancer. First, ETP was pre-formulated as phospholipid complex (EPC) to enhance drug solubility and facilitate its encapsulation within the hydrophilic albumin nanoparticles (NPs). Second, EPC and BER were then co-loaded with high efficiency into HSA NPs as a synergistic therapy for lung cancer. The NPs displayed suitable size around 200 nm and sequential drug release pattern. Moreover, conjugation of aminophenylboronic acid (APBA) to HSA NPs resulted in enhanced cytotoxicity and internalization into A549 lung cancer cells, compared to non-targeted NPs or free drugs via binding to sialic acid residues over-expressed by cancer cells. Using mannitol as a spray-drying carrier, the developed inhalable nanocomposites demonstrated deep pulmonary deposition, confirmed by small MMAD (2.112 µm) and high FPF (77.86%). In vivo investigations in lung cancer animal models revealed the superior anti-tumor efficacy of the inhalable nanocomposites. Overall, the inhalable APBA-HSA nanocomposites offered an alternative strategy for systemic delivery of ETP and BER in lung cancer therapy.

Synthetic and Natural Lipase Inhibitors.

Lipases are enzymes that catalyse the hydrolysis of ester bonds of triglycerides ranging among biocatalysts of considerable physiological significance and industrial potential. Better understanding of the catalytic functions and achieving the possibility to control the biocatalysis process, in particular exploring some activators and inhibitors of lipases, seems to be crucial in the context of novel applications. The lipase activity is a function of interfacial composition: the enzyme can be there activated as well as denaturated or deactivated and the interface is an appropriate site for modulating lipolysis. Lipase inhibitor, interacts directly with the enzyme and inhibits lipase action. Alternatively, some compounds can postpone the lipolytic reaction via adsorption to the interphase or to the substrate molecules. The aim of this review is to summarise the current knowledge concerning human, animal and microbial lipase inhibitors, which were grouped into two categories: synthetic lipase inhibitors (including phosphonates, boronic acids and fats analogues) and natural compounds (including ß-lactones and some botanical foodstuffs - plant extracts and plant metabolites, mainly polyphenols and saponins as well as peptides and some dietary fibers). The topics discussed include also inhibition issues from the viewpoint of obesity treatment. Among natural compounds able to inhibit lipase activity are ß- lactones including orlistat. Orlistat is the only registered drug for obesity treatment in many countries and lipases are essential enzymes for lipid absorption - thus fat absorption or obesity can be controlled by lipase inhibition, especially pancreatic lipase which is responsible for the hydrolysis of over 80% of total dietary fats. Its effectiveness in obesity treatment was also described.

Phenylboronic-acid-based carbohydrate binders as antiviral therapeutics: monophenylboronic acids.

BACKGROUND: The development of carbohydrate-binding agents as novel therapeutics for the inhibition of highly glycosylated enveloped viruses has generated much attention in recent literature. Possessing a potential dual mode of action by inhibiting virus entry and exposing the virion to neutralization by the host immune system upon the deletion of envelope glycans under drug pressure, these substances might provide a new direction in antiviral treatment. Phenylboronic acids are widely known to bind the cis-diol functionality of carbohydrate structures, thereby identifying themselves as potential lead structures. To date, few details have been disclosed of the structure-activity relationship of these substances in correlation to their antiviral activity. METHODS: In this study, a compound library of a diverse range of ortho-, meta- and para- ring-substituted monophenylboronic acids and glutamine phenylboronic acid analogues was prepared, characterized and evaluated to probe antiviral activity versus a broad range of (enveloped) viruses. RESULTS: The compounds described herein lack antiviral activity. They also did not show measurable binding to HIV type-1 (HIV-1) gp120, using surface plasmon resonance technology. However, of note is the general lack of toxicity, which suggests that further investigation of the compounds as potential therapeutics is needed. CONCLUSIONS: The monophenylboronic acids tested exhibited no antiviral activity as potential carbohydrate binders versus a broad range of enveloped and non-enveloped viruses. The compounds tested did not bind HIV-1 gp120, possibly because of their small size and lack of multivalency.

Boronic acid-based inhibitor of autotaxin reveals rapid turnover of LPA in the circulation.

Autotaxin (ATX) is a secreted nucleotide pyrophosphatase/phosphodiesterase that functions as a lysophospholipase D to produce the lipid mediator lysophosphatidic acid (LPA), a mitogen, chemoattractant, and survival factor for many cell types. The ATX-LPA signaling axis has been implicated in angiogenesis, chronic inflammation, fibrotic diseases and tumor progression, making this system an attractive target for therapy. However, potent and selective nonlipid inhibitors of ATX are currently not available. By screening a chemical library, we have identified thiazolidinediones that selectively inhibit ATX-mediated LPA production both in vitro and in vivo. Inhibitor potency was approximately 100-fold increased (IC(50) approximately 30 nM) after the incorporation of a boronic acid moiety, designed to target the active-site threonine (T210) in ATX. Intravenous injection of this inhibitor into mice resulted in a surprisingly rapid decrease in plasma LPA levels, indicating that turnover of LPA in the circulation is much more dynamic than previously appreciated. Thus, boronic acid-based small molecules hold promise as candidate drugs to target ATX.