Biology subjects

Koo, A.

Publications and source records attributed to Koo, A..

4 recordsLinked to original sources

bioRxiv2025

Non-invasive approach for endoluminal biopsy coupled with single-cell proteomics allows for immune characterization of intracranial aneurysms

The immune regulatory mechanisms driving the stability, growth, and rupture of intracranial aneurysms (IAs) remain incompletely understood. In this study, we employ endoluminal biopsy with single-cell proteomics to comprehensively profile the immune landscape of IAs across their pathologic states. Our findings reveal distinct immune signatures associated with aneurysm states. Stable, i.e. non-growing unruptured, IAs exhibit a balanced immune cell composition. Ruptured IAs are marked by significant neutrophil predominance. Notably, we highlight key immune markers in aneurysm instability, offering new insights into immune drivers of aneurysm progression. These findings provide a foundation for immune-targeted, non-invasive therapeutic strategies aimed at targeting IAs and preventing rupture.

physiology↗

bioRxiv2024

Food entrainment in mice leads to sex- and organ-specific responses in nutrient metabolism

Food intake is one of the main zeitgebers in the digestive system; however, little is known about organ- and sex-specific differences in food-driven regulation. We placed male and female C57Bl/6 mice on time-restricted feeding (TRF), limiting the food intake period to 8 hours. Food was added either at dark (ZT12) or light (ZT0) onset for 14 days. Afterwards, an additional 4-hour delay in the feeding period was introduced for half of the mice, and the TRF regime continued for another 14 days. TRF from ZT12 to ZT20 led to the highest weight gain in females but the lowest in males while improving intestinal transepithelial resistance (TEER) in both sexes. However, it also led to the disappearance of food-anticipatory response in several hepatic genes. Delaying the start of TRF until ZT16 led to an increase in weight gain and a decrease in fasting plasma glucose levels in male mice, as well as to strong entrainment of metabolism-related hepatic and duodenal genes in both sexes. The alignment of food intake with the early lights-on phase (ZT0-ZT8) caused only minor changes in physiological responses. However, it did lead to an overall downregulation of hepatic and an upregulation of duodenal and gastric genes, with additional loss of food-anticipatory gene expression in both sexes. Delaying the start of food intake until ZT4 was highly detrimental, causing an increase in fasting blood glucose levels, a decrease in TEER, and further disruptions in gene expression patterns in the stomach and liver. In contrast, the duodenum was able to restore its food-driven gene expression. These results demonstrate that the adjustment to food intake time in mice is highly sex- and organ-specific. Our chosen TRF regimes were not able to synchronize food-anticipatory responses between the liver and gut. Instead, we observed that organs entrain to food intake at different rates.

molecular biology↗

bioRxiv2023

Stratification of enterochromaffin cells by single-cell expression analysis

Dynamic interactions between gut mucosal cells and the external environment are essential to maintain gut homeostasis. Enterochromaffin (EC) cells transduce both chemical and mechanical signals and produce 5-hydroxytryptamine (5-HT) to mediate disparate physiological responses. However, the molecular and cellular basis for functional diversity of ECs remains to be adequately defined. Here, we integrated single-cell transcriptomics with spatial image analysis to identify fourteen EC clusters that are topographically organized along the gut. Subtypes predicted to be sensitive to the chemical environment and mechanical forces were identified that express distinct transcription factors and hormones. A Piezo2+ population in the distal colon was endowed with a distinctive neuronal signature. Using a combination of genetic, chemogenetic and pharmacological approaches, we demonstrated Piezo2+ ECs are required for normal colon motility. Our study constructs a molecular map for ECs and offers a framework for deconvoluting EC cells with pleiotropic functions.

cell biology↗

bioRxiv2023

In vivo proton MR Spectroscopy of the healthy and diseased human brain

Proton (1H) Magnetic Resonance Spectroscopy (MRS) is a non-invasive tool capable of quantifying brain metabolite concentrations in vivo. Prioritization of standardization and accessibility in the field has led to the development of universal pulse sequences, methodological consensus recommendations, and the development of open-source analysis software packages. One on-going challenge is methodological validation with ground-truth data. As ground-truths are rarely available for in vivo measurements, data simulations have become an important tool. The diverse literature of metabolite measurements has made it challenging to define ranges to be used within simulations. Especially for the development of deep learning and machine learning algorithms, simulations must be able to produce accurate spectra capturing all the nuances of in vivo data. Therefore, we sought to determine the physiological ranges and relaxation rates of brain metabolites which can be used both in data simulations and as reference estimates. Using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, weve identified relevant MRS research articles and created an open-source database containing methods, results, and other article information as a resource. Using this database, expectation values and ranges for metabolite concentrations and T2 relaxation times are established based upon a meta-analyses of healthy and diseased brains.

neuroscience↗