Electrophysiological- and Neuropharmacological-Based Benchmarking of Human Induced Pluripotent Stem Cell-Derived and Primary Rodent Neurons.

Human induced pluripotent stem cell (iPSC)-derived neurons are of interest for studying neurological disease mechanisms, developing potential therapies and deepening our understanding of the human nervous system. However, compared to an extensive history of practice with primary rodent neuron cultures, human iPSC-neurons still require more robust characterization of expression of neuronal receptors and ion channels and functional and predictive pharmacological responses. In this study, we differentiated human amniotic fluid-derived iPSCs into a mixed population of neurons (AF-iNs). Functional assessments were performed by evaluating electrophysiological (patch-clamp) properties and the effect of a panel of neuropharmacological agents on spontaneous activity (multi-electrode arrays; MEAs). These electrophysiological data were benchmarked relative to commercially sourced human iPSC-derived neurons (CNS.4U from Ncardia), primary human neurons (ScienCell™) and primary rodent cortical/hippocampal neurons. Patch-clamp whole-cell recordings showed that mature AF-iNs generated repetitive firing of action potentials in response to depolarizations, similar to that of primary rodent cortical/hippocampal neurons, with nearly half of the neurons displaying spontaneous post-synaptic currents. Immunochemical and MEA-based analyses indicated that AF-iNs were composed of functional glutamatergic excitatory and inhibitory GABAergic neurons. Principal component analysis of MEA data indicated that human AF-iN and rat neurons exhibited distinct pharmacological and electrophysiological properties. Collectively, this study establishes a necessary prerequisite for AF-iNs as a human neuron culture model suitable for pharmacological studies.

Correction to: LyP-1 Conjugated Nanoparticles for Magnetic Resonance Imaging of Triple Negative Breast Cancer.

This article was updated to correct the spelling of B. Gino Fallone's name; it is correct as displayed above. Correction to: Mol Imaging Biol (2017). DOI: https://doi.org/10.1007/s11307-017-1140-4.

LyP-1 Conjugated Nanoparticles for Magnetic Resonance Imaging of Triple Negative Breast Cancer.

PURPOSE: Triple-negative breast cancer (TNBC) does not express estrogen receptor, progesterone receptor, or Her2/neu. Both diagnosis and treatment of TNBC remain a clinical challenge. LyP-1 is a cyclic 9 amino acid peptide that can bind to breast cancer cells. The goal of this study was to design and characterize LyP-1 conjugated to fluorescent iron oxide nanoparticles (LyP-1-Fe3O4-Cy5.5) as a contrast agent for improved and specific magnetic resonance imaging (MRI) in a preclinical model of TNBC. PROCEDURES: The binding of LyP-1-Fe3O4-Cy5.5 to MDA-MB-231 TNBC cells was evaluated and compared to scrambled peptide bio-conjugated to iron oxide nanoparticles (Ctlpep-Fe3O4-Cy5.5) as a negative control. Following the in vitro study, the MDA-MB-231 cells were injected into mammary glands of nude mice. Mice were divided into two groups: control group received Ctlpep- Fe3O4-Cy5.5 and LyP-1 group received LyP-1-Fe3O4-Cy5.5 (tail vein injection at 2 mg/kg of Fe3O4). Mice were imaged with an in vivo fluorescence imager and a 9.4 T MRI system at various time points after contrast agent injection. The T2 relaxation time was measured to observe accumulation of the contrast agent in breast tumor and muscle for both targeted and non-targeted contrast agents. RESULTS: Immunofluorescence revealed dense binding of the LyP-1-Fe3O4-Cy5.5 contrast agent to MDA-MB-231 cells; while little appreciable binding was observed to the scrambled negative control (Ctlpep-Fe3O4-Cy5.5). Optical imaging performed in tumor-bearing mice showed increased fluorescent signal in mammary gland of animals injected by LyP-1-Fe3O4-Cy5.5 but not Ctlpep- Fe3O4-Cy5.5. The results were confirmed ex vivo by the 2.6-fold increase of fluorescent signal from LyP-1-Fe3O4-Cy5.5 in extracted tumors when compared to the negative control. In MR imaging studies, there was a statistically significant (P < 0.01) difference in normalized T2 between healthy breast and tumor tissue at 1, 2, and 24 h post injection of the LyP-1-Fe3O4-Cy5.5. In animals injected with LyP-1-Fe3O4, distinct ring-like structures were observed with clear contrast between the tumor core and rim. CONCLUSION: The results demonstrate that LyP-1-Fe3O4 significantly improves MRI contrast of TNBC, hence has the potential to be exploited for the specific delivery of cancer therapeutics.

Development of an Anti-Vascular Cell Adhesion Protein-1 Aptamer for Molecular Imaging and Inflammation Detection in Transgenic Mouse Model of Alzheimer's Disease.

Cerebrovascular inflammation is often involved in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease (AD). Non-invasive and sensitive molecular imaging of cerebrovascular inflammation biomarkers therefore represents a potential AD diagnostic and therapeutic monitoring method. Here, we describe the development of a novel aptamer-based near infrared fluorescence imaging probe targeting Vascular Cell Adhesion Molecule-1 (VCAM-1), an adhesion molecule overexpressed by the activated cerebrovasculature during inflammation. A SELEX-type screening of a random ssDNA library against human VCAM-1 identified a high-affinity ssDNA aptamer with a dissociation constant of 49 nM. We demonstrated that the Cy5.5-labeled aptamer binds to activated endothelial cells, with no affinity to non-activated cells. A scrambled aptamer labeled with Cy5.5 did not image activated and non-activated endothelial cells, confirming the sequence specificity of the targeting. In vivo, the aptameric imaging agent targeting VCAM-1 successfully identified inflammation associated with amyloid-ß plaques deposition in the vessels of the cerebellum of transgenic AD mice. It exhibited excellent retention by remaining bound to vessels 4 hours post-injection, indicating its effectiveness in in vivo imaging and its potential in early detection of cerebrovascular inflammation.