Biology subjects

Miller, F. J.

Publications and source records attributed to Miller, F. J..

3 recordsLinked to original sources

bioRxiv2026

Nox4 Mediates Diastolic Function in a Genetic Model of Pitx2 Haploinsufficiency

Heart failure with preserved ejection fraction (HFpEF) commonly coexists with atrial fibrillation (AF), but shared mechanisms remain unclear. In this study, we hypothesized that Pitx2, a transcription factor located near the strongest genetic locus associated with AF in humans, increases susceptibility to HFpEF-like remodeling. We also sought to understand pathways that might be central to this increased risk. Male and female Pitx2+/- mice and wild-type littermates received 3-week subcutaneous osmotic pump infusion of saline or angiotensin II (Ang II; 500 ng/kg/min). Cardiac structure and function were assessed by echocardiography and catheterization, and functional capacity by exercise treadmill. RNA transcriptomic profiling was performed to identify candidate pathways. In a separate cohort, Ang II-treated mice were randomized to oral GKT136901 (30 mg/kg/day) or vehicle during infusion. After Ang II infusion, Pitx2+/- mice developed exaggerated HFpEF-like changes, including greater left ventricular hypertrophy, left atrial enlargement, diastolic dysfunction, elevated left ventricular end-diastolic pressure, and reduced treadmill performance. RNA-seq showed enrichment of metabolic and stress-response pathways with selective upregulation of Nox4, confirmed by RT-qPCR. GKT136901 attenuated structural remodeling, diastolic dysfunction indices, elevated filling pressures, and cardiomyocyte hypertrophy, but did not improve endurance. These findings implicate redox signaling, including Nox4, in AF genetic susceptibility-HFpEF interactions.

cell biology↗

bioRxiv2022

The endothelial-specific LINC00607 mediates endothelial angiogenic function

Long non-coding RNAs (lncRNAs) can act as regulatory RNAs which, by altering the expression of target genes, impact on the cellular phenotype and cardiovascular disease development. Endothelial lncRNAs and their vascular functions are largely undefined. Deep RNA-Seq and FANTOM5 CAGE analysis revealed the lncRNA LINC00607 to be highly enriched in human endothelial cells. LINC00607 was induced in response to hypoxia, arteriosclerosis regression in non-human primates and also in response to propranolol used to induce regression of human arteriovenous malformations. siRNA knockdown or CRISPR/Cas9 knockout of LINC00607 attenuated VEGF-A-induced angiogenic sprouting. LINC00607 knockout in endothelial cells also integrated less into newly formed vascular networks in an in vivo assay in SCID mice. Overexpression of LINC00607 in CRISPR knockout cells restored normal endothelial function. RNA- and ATAC-Seq after LINC00607 knockout revealed changes in the transcription of endothelial gene sets linked to the endothelial phenotype and in chromatin accessibility around ERG-binding sites. Mechanistically, LINC00607 interacted with the SWI/SNF chromatin remodeling protein BRG1. CRISPR/Cas9-mediated knockout of BRG1 in HUVEC followed by CUT&RUN revealed that BRG1 is required to secure a stable chromatin state, mainly on ERG-binding sites. In conclusion, LINC00607 is an endothelial-enriched lncRNA that maintains ERG target gene transcription by interacting with the chromatin remodeler BRG1.

molecular biology↗

bioRxiv2020

Light Sheet Fluorescence Microscopy as a New Method for Unbiased Three-Dimensional Analysis of Vascular Injury

AimsAssessment of preclinical models of vascular disease are paramount in the successful translation of novel treatments. The results of these models have traditionally relied on 2-D histological methodologies. Light sheet fluorescence microscopy (LSFM) is an imaging platform that allows for 3-D visualization of whole organs and tissues. In this study, we describe an improved methodological approach utilizing LSFM for imaging of preclinical vascular injury models while minimizing analysis bias. Methods and ResultsThe rat carotid artery segmental pressure-controlled balloon injury and mouse carotid artery ligation injury were performed. Arteries were harvested and processed for LSFM imaging and 3-D analysis, as well as for 2-D area histological analysis. Artery processing for LSFM imaging did not induce vessel shrinkage or expansion, and was reversible by rehydrating the artery, allowing for subsequent sectioning and histological staining a posteriori. By generating a volumetric visualization along the length of the arteries, LSFM imaging provided different analysis modalities including volumetric, area, and radial parameters. Thus, LSFM-imaged arteries provided more precise measurements compared to classic histological analysis. Furthermore, LSFM provided additional information as compared to 2-D analysis in demonstrating remodeling of the arterial media in regions of hyperplasia and periadventitial neovascularization around the ligated mouse artery. ConclusionsLSFM provides a novel and robust 3-D imaging platform for visualizing and quantifying arterial injury in preclinical models. When compared with classic histology, LSFM outperformed traditional methods in precision and quantitative capabilities. LSFM allows for more comprehensive quantitation as compared to traditional histological methodologies, while minimizing user bias associated with area analysis of alternating, 2-D histological artery cross-sections. Translational PerspectiveA more reproducible and robust quantitation of vascular pathology in preclinical models is necessary to accelerate translational discovery. Current methodology to assess vascular disease has significant limitations. The methodology described herein employs a modern imaging modality, light sheet fluorescence microscopy (LSFM), to improve assessment of established preclinical vascular injury models. LSFM provides more comprehensive and precise analysis capabilities than classical histological approaches. Hence, LSFM applied to vascular research has the potential to drive new basic discoveries, and ultimately translation of novel therapies.

pathology↗