Biology subjects

Moats, R. A.

Publications and source records attributed to Moats, R. A..

4 recordsLinked to original sources

bioRxiv2024

Advancing Clinical Response Against Glioblastoma: Evaluating SHP1705 CRY2 Activator Efficacy in Preclinical Models and Safety in Phase I Trials

BackgroundIt has been reported that circadian clock components, Brain and Muscle ARNT-Like 1 (BMAL1) and Circadian Locomotor Output Cycles Kaput (CLOCK), are uniquely essential for glioblastoma (GBM) stem cell (GSC) biology and survival. Consequently, we developed a novel Cryptochrome (CRY) activator SHP1705, which inhibits BMAL1-CLOCK transcriptional activity. MethodsWe analyzed buffy coats isolated from Phase 1 clinical trial subjects blood to assess any changes to circadian, housekeeping, and blood transcriptome-based biomarkers following SHP1705 treatment. We utilized GlioVis to determine which circadian genes are differentially expressed in non-tumor versus GBM tissues. We employed in vitro and in vivo methods to test the efficacy of SHP1705 against patient-derived GSCs and xenografts in comparison to earlier CRY activator scaffolds. Additionally, we applied a novel-REV-ERB agonist SR29065, which inhibits BMAL1 transcription, to determine whether targeting both negative limbs of the circadian transcription-translation feedback loop (TTFL) would yield synergistic effects against various GBM cells. ResultsSHP1705 is safe and well-tolerated in Phase I clinical trials. SHP1705 has increased selectivity for the CRY2 isoform and potency against GSC viability compared to previously published CRY activators. SHP1705 prolonged survival in mice bearing GBM tumors established with GSCs. When combined with the novel REV-ERB agonist SR29065, SHP1705 displayed synergy against multiple GSC lines and differentiated GSCs (DGCs). ConclusionsThese demonstrate the efficacy of SHP1705 against GSCs, which pose for GBM patient outcomes. They highlight the potential of novel circadian clock compounds in targeting GBM as single agents or in combination with each other or current standard-of-care. KEY POINTSO_LISHP1705 is a novel CRY2 activator that has shown success in Phase 1 safety trials C_LIO_LISHP1705 has a significantly improved efficacy against GSCs and GBM PDX tumors C_LIO_LINovel REV-ERB agonist SR29065 and SHP1705 display synergistic effects against GSCs C_LI IMPORTANCE OF THE STUDYCRY2 is decreased in GBM tissues compared to CRY1 suggesting that promoting CRY2 activity will be an efficacious GBM treatment paradigm. SHP1705, a CRY2 activator that has shown success in Phase 1 safety trials, has significantly improved preclinical efficacy. Novel REV-ERB agonist SR29065 displays synergistic effects against diverse GBM cells.

cancer biology↗

bioRxiv2024

Mouse Brain Extractor: Brain segmentation of mouse MRI using global positional encoding and SwinUNETR

In spite of the great progress that has been made towards automating brain extraction in human magnetic resonance imaging (MRI), challenges remain in the automation of this task for mouse models of brain disorders. Researchers often resort to editing brain segmentation results manually when automated methods fail to produce accurate delineations. However, manual corrections can be labor-intensive and introduce interrater variability. This motivated our development of a new deep-learning-based method for brain segmentation of mouse MRI, which we call Mouse Brain Extractor. We adapted the existing SwinUNETR architecture (Hatamizadeh et al., 2021) with the goal of making it more robust to scale variance. Our approach is to supply the network model with supplementary spatial information in the form of absolute positional encoding. We use a new scheme for positional encoding, which we call Global Positional Encoding (GPE). GPE is based on a shared coordinate frame that is relative to the entire input image. This differs from the positional encoding used in SwinUNETR, which solely employs relative pairwise image patch positions. GPE also differs from the conventional absolute positional encoding approach, which encodes position relative to a subimage rather than the entire image. We trained and tested our method on a heterogeneous dataset of N=223 mouse MRI, for which we generated a corresponding set of manually-edited brain masks. These data were acquired previously in other studies using several different scanners and imaging protocols and included in vivo and ex vivo images of mice with heterogeneous brain structure due to different genotypes, strains, diseases, ages, and sexes. We evaluated our methods results against those of seven existing rodent brain extraction methods and two state-of-the art deep-learning approaches, nnU-Net (Isensee et al., 2018) and SwinUNETR. Overall, our proposed method achieved average Dice scores on the order of 0.98 and average HD95 measures on the order of 100 {micro}m when compared to the manually-labeled brain masks. In statistical analyses, our method significantly outperformed the conventional approaches and performed as well as or significantly better than the nnU-Net and SwinUNETR methods. These results suggest that Global Positional Encoding provides additional contextual information that enables our Mouse Brain Extractor to perform competitively on datasets containing multiple resolutions.

neuroscience↗

bioRxiv2023

Episodic live imaging of cone photoreceptor maturation in GNAT2-EGFP retinal organoids

Fluorescent reporter pluripotent stem cell (PSC) derived retinal organoids are powerful tools to investigate cell type-specific development and disease phenotypes. When combined with live imaging, they enable direct and repeated observation of cell behaviors within a developing retinal tissue. Here, we generated a human cone photoreceptor reporter line by CRISPR/Cas9 genome editing of WTC11-mTagRFPT-LMNB1 human induced pluripotent stem cells (iPSCs) by inserting enhanced green fluorescent protein (EGFP) coding sequences and a 2A self-cleaving peptide at the N-terminus of Guanine Nucleotide-Binding Protein Subunit Alpha Transducin 2 (GNAT2). In retinal organoids generated from these iPSCs, the GNAT2-EGFP allele robustly and exclusively labeled both immature and mature cones starting at culture day 34. Episodic confocal live imaging of hydrogel immobilized retinal organoids allowed tracking of morphological maturation of individual cones for >18 weeks and revealed inner segment accumulation of mitochondria and growth at 12.2 cubic microns per day from day 126 to day 153. Immobilized GNAT2-EGFP cone reporter organoids provide a valuable tool for investigating human cone development and disease.

developmental biology↗

bioRxiv2018

Continuous and bolus intraventricular topotecan prolong survival in a mouse model of leptomeningeal medulloblastoma

Leptomeningeal metastasis remains a difficult clinical challenge. Some success has been achieved by direct administration of therapeutics into the cerebrospinal fluid (CSF) circumventing limitations imposed by the blood brain barrier. Here we investigated continuous infusion versus bolus injection of therapy into the CSF in a preclinical model of human Group 3 medulloblastoma, the molecular subgroup with the highest incidence of leptomeningeal disease. Initial tests of selected Group 3 human medulloblastoma cell lines in culture showed that D283 Med and D425 Med were resistant to cytarabine and methotrexate. D283 Med cells were also resistant to topotecan, whereas 1 M topotecan killed over 99% of D425 Med cells. We therefore introduced D425 Med cells, modified to express firefly luciferase, into the CSF of immunodeficient mice. Mice were then treated with topotecan or saline in five groups: continuous intraventricular (IVT) topotecan via osmotic pump (5.28 g/day), daily bolus IVT topotecan injections with a similar daily dose (6 g/day), systemic intraperitoneal injections of a higher daily dose of topotecan (15 g/day), daily IVT pumped saline and daily intraperitoneal injections of saline. Bioluminescence analyses revealed that both IVT topotecan treatments effectively slowed leptomeningeal tumor growth in the brains, although histological analysis showed that they were associated with localized brain necrosis. In the spines, bolus IVT topotecan showed a trend towards slower tumor growth compared to continuous (pump) IVT topotecan, as measured by bioluminescence. Both continuous and bolus topotecan IVT showed similar survival that was longer compared to other groups. Thus, both direct IVT topotecan CSF delivery methods produced better anti-medulloblastoma effect compared to systemic therapy at the dosages used here.

cancer biology↗