Investigation of novel mitoNEET ligand NL-1 as a therapeutic for cerebral ischemia and reperfusion injury

Cerebral ischemia reperfusion injury, a common type of stroke, is a neurodegenerative disorder which is the leading cause of permanent disability in the United States. The underlying pathophysiology of ischemic stroke involves an occlusion in the vasculature supplying oxygen and glucose to the brain tissue, leading to infarction and eventual necrosis in the brain. MitoNEET is an outer mitochondrial protein that plays a role in the cellular bioenergetics and its redox physiology. Although its endogenous ligands are under investigation, mitoNEET binds molecules with a thiazolidinedione moiety, such as NL-1. This dissertation investigates NL-1 as a potential cytoprotective agent, and its possible use as a stroke therapeutic. After establishing the binding of NL-1 to mitoNEET, the effects of the drug on cellular bioenergetics as well as the mitochondrial function were studied. Upon the successful preliminary studies, NL-1 was formulated into a polymeric nanoparticle system and its efficacy evaluated in an in vitro stroke model on endothelial cells. The NL-1 loaded nanoparticles were found to reduce the generation of cell damaging peroxide, which is an important component of the oxidative stress causing milieu. The NL-1 nanoparticles also helped improve cell survival by decreasing the apoptotic cell population, one of the principal modes of cell damage following stroke. To evaluate promising in vitro results in vivo, a two-hour transient middle cerebral artery occlusion model was utilized. Analysis of brain sections after 24 hours showed a significantly reduced infarct volume and hemispheric swelling following treatment with NL-1 and NL-1 nanoparticles. Reduced levels of IgG extravasation were seen in treated animals compared to controls, after a 72-hour period following treatment. Qualitative analysis also revealed decreased staining area and intensity for GFAP, nitrotyrosine and 4-hydroxynonenal. Future studies need to be focused on determining the exact mechanism of action of NL-1 in the mitochondrial axis, which could help improve its dosing. A long-term study with focus on cognitive and motor neurological outcomes, following treatment with NL-1 would be the primary translational future aim. In summary, this dissertation establishes the preliminary basis for use of NL-1 as a stroke therapeutic which could compliment the current therapy in alleviating the effects of reperfusion injury

Investigational chemotherapy and novel pharmacokinetic mechanisms for the treatment of breast cancer brain metastases

In women, breast cancer is the most common cancer diagnosis and second most common cause of cancer death. More than half of breast cancer patients will develop metastases to the bone, liver, lung, or brain. Breast cancer brain metastases (BCBM) confers a poor prognosis, as current therapeutic options of surgery, radiation, and chemotherapy rarely significantly extend life and are considered palliative. Within the realm of chemotherapy, the last decade has seen an explosion of novel chemotherapeutics involving targeting agents and unique dosage forms. We provide a historical overview of BCBM chemotherapy, review the mechanisms of new agents such as poly-ADP ribose polymerase inhibitors, cyclin-dependent kinase 4/6 inhibitors, phosphatidyl inositol 3-kinaseinhibitors, estrogen pathway antagonists for hormone-receptor positive BCBM; tyrosine kinase inhibitors, antibodies, and conjugates for HER2+ BCBM; repurposed cytotoxic chemotherapy for triple negative BCBM; and the utilization of these new agents and formulations in ongoing clinical trials. The mechanisms of novel dosage formulations such as nanoparticles, liposomes, pegylation, the concepts of enhanced permeation and retention, and drugs utilizing these concepts involved in clinical trials are also discussed. These new treatments provide a promising outlook in the treatment of BCBM

Crystal Structure of the Mitochondrial Protein mitoNEET Bound to a Benze-sulfonide Ligand

MitoNEET (gene cisd1) is a mitochondrial outer membrane [2Fe-2S] protein and is a potential drug target in several metabolic diseases. Previous studies have demonstrated that mitoNEET functions as a redox-active and pH-sensing protein that regulates mitochondrial metabolism, although the structural basis of the potential drug binding site(s) remains elusive. Here we report the crystal structure of the soluble domain of human mitoNEET with a sulfonamide ligand, furosemide. Exploration of the high-resolution crystal structure is used to design mitoNEET binding molecules in a pilot study of molecular probes for use in future development of mitochondrial targeted therapies for a wide variety of metabolic diseases, including obesity, diabetes and neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease

Crystal structure of the mitochondrial protein mitoNEET bound to a benze-sulfonide ligand

MitoNEET (gene cisd1) is a mitochondrial outer membrane [2Fe-2S] protein and is a potential drug target in several metabolic diseases. Previous studies have demonstrated that mitoNEET functions as a redox-active and pH-sensing protein that regulates mitochondrial metabolism, although the structural basis of the potential drug binding site(s) remains elusive. Here we report the crystal structure of the soluble domain of human mitoNEET with a sulfonamide ligand, furosemide. Exploration of the high-resolution crystal structure is used to design mitoNEET binding molecules in a pilot study of molecular probes for use in future development of mitochondrial targeted therapies for a wide variety of metabolic diseases, including obesity, diabetes and neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease

Allicin- inspired pyridyl disulfides as antimicrobial agents for multidrug-resistant Staphylococcus aureus

A chemical library comprised of nineteen synthesized pyridyl disulfides that emulate the chemical reactivity of allicin (garlic) was evaluated for antimicrobial activity against a panel of pathogenic bacteria. Gram-positive species including vancomycin-intermediate and vancomycin-resistant Staphylococcus aureus (VISA, VRSA) demonstrated the highest level of susceptibility toward analogs with S-alkyl chains of 7–9 carbons in length. Further biological studies revealed that the disulfides display synergy with vancomycin against VRSA, cause dispersal of S. aureus biofilms, exhibit low cytotoxicity, and decelerate S. aureus metabolism. In final analysis, pyridyl disulfides represent a novel class of mechanism-based antibacterial agents that have a potential application as antibiotic adjuvants in combination therapy of S. aureus infections with reduced vancomycin susceptibility

Disulfiram-based disulfides as narrow-spectrum antibacterial agents

Sixteen disulfides derived from disulfiram (Antabuse™) were evaluated as antibacterial agents. Derivatives with hydrocarbon chains of seven and eight carbons in length exhibited antibacterial activity against Gram-positive Staphylococcus, Streptococcus, Enterococcus, Bacillus, and Listeria spp. A comparison of the cytotoxicity and microsomal stability with disulfiram further revealed that the eight carbon chain analog was of lower toxicity to human hepatocytes and has a longer metabolic half-life. In the final analysis, this investigation concluded that the S-octylthio derivative is a more effective growth inhibitor of Gram-positive bacteria than disulfiram and exhibits more favorable cytotoxic and metabolic parameters over disulfiram

A Review of Mathematics Determining Solute Uptake at the Blood–Brain Barrier in Normal and Pathological Conditions

The blood–brain barrier (BBB) limits movement of solutes from the lumen of the brain microvascular capillary system into the parenchyma. The unidirectional transfer constant, Kin, is the rate at which transport across the BBB occurs for individual molecules. Single and multiple uptake experiments are available for the determination of Kin for new drug candidates using both intravenous and in situ protocols. Additionally, the single uptake method can be used to determine Kin in heterogeneous pathophysiological conditions such as stroke, brain cancers, and Alzheimer’s disease. In this review, we briefly cover the anatomy and physiology of the BBB, discuss the impact of efflux transporters on solute uptake, and provide an overview of the single-timepoint method for determination of Kin values. Lastly, we compare preclinical Kin experimental results with human parallels

Hypomethylating Agent Azacitidine Is Effective in Treating Brain Metastasis Triple-Negative Breast Cancer Through Regulation of DNA Methylation of Keratin 18 Gene.

Breast cancer patients presenting with symptomatic brain metastases have poor prognosis, and current chemotherapeutic agents are largely ineffective. In this study, we evaluated the hypomethylating agent azacitidine (AZA) for its potential as a novel therapeutic in preclinical models of brain metastasis of breast cancer. We used the parental triple-negative breast cancer MDA-MB-231 (231) cells and their brain colonizing counterpart (231Br) to ascertain phenotypic differences in response to AZA. We observed that 231Br cells have higher metastatic potential compared to 231 cells. With regard to therapeutic value, the AZA I