bioRxiv Science⌕ Search

Biology subjects

Botto, E.

Publications and source records attributed to Botto, E..

2 recordsLinked to original sources

A harmonized phantom MRI quality control framework identifies sources of longitudinal and multi-site variability

The shift towards open science in preclinical research requires high-quality, comparable data adhering to FAIR principles, yet rigorous quality assurance (QA) and quality control (QC) frameworks remain less established in preclinical magnetic resonance imaging (MRI) than in clinical imaging. To address this limitation, a multicenter study was conducted across 21 international laboratories using standardized commercial liquid phantoms for mouse and rat MRI setups and a harmonized acquisition protocol. Data processing was centralized using AIDAqc, an automated pipeline extracting quantitative metrics including signal-to-noise ratio (SNR), temporal SNR (tSNR), ghost-to-signal ratio (GSR), and motion-equivalent temporal instability, combined with five complementary outlier-detection algorithms. The evaluated datasets encompassed magnetic field strengths from 3.0 to 16.4 T and heterogeneous coil and acquisition configurations. In mouse phantom data, SNR and tSNR were significantly lower at 3 T than at 7 and 9.4 T, whereas artifact-related metrics did not differ significantly between field-strength groups. In rat phantom data, differences between field strengths were less pronounced. At 7 T, substantial dataset-specific differences were observed in anatomical and functional quality metrics, also among datasets using the similar coil configuration. Multicenter reference values for frequently represented 7 T configurations were established, including SNR/tSNR of 48 {+/-} 3/48 {+/-} 1 dB for mouse surface-coil datasets and 49 {+/-} 3/44 {+/-} 4 dB for rat array-coil datasets. Longitudinal anatomical SNR showed generally low variability, whereas ghosting was more variable across time. Automated outlier detection additionally identified transient acquisition instabilities that were not always apparent by visual inspection. Together, these findings show that field strength and nominal coil configuration alone do not adequately characterize MRI performance and support standardized, longitudinal phantom-based QC combined with automated analysis as a practical approach for improving the reliability, transparency, and interoperability of multicenter preclinical MRI data.

bioengineering↗

Niche cytoskeletal architecture is required for proper stem cell signaling and oriented division in the Drosophila testis

Stem cells are critical to repair and regenerate tissues, and often reside in a niche that controls their behavior. The Drosophila testis niche has been a paradigm for niche-stem cell interactions and is used here to address the cell biological features that maintain niche structure and function during its steady-state operation. We report enrichment of the Myosin II (MyoII) and a key regulator of acto-myosin contractility (AMC), Rho Kinase (ROK), within the niche cell cortex at the interface with germline stem cells (GSCs). Compromising MyoII and ROK disrupts niche architecture, suggesting that AMC in niche cells is important to maintain the reproducible structure of this niche. Furthermore, defects in niche architecture cause changes in stem cell function. Our data suggest that the niche signals less robustly to adjacent germ cells, yet the disrupted structure permits increased numbers of cells to respond to the signal. Finally, compromising Myo II in niche cells leads to an increase in mis-oriented centrosomes in GSCs as well as defects in the centrosome orientation checkpoint. Ultimately, this work identifies a critical role for AMC-dependent maintenance of niche structure to ensure a proper complement of stem cells with correct execution of stem cell divisions. Summary statementActomyosin contractility regulated niche architecture is critical for proper signaling and oriented division of germline stem cells.

developmental biology↗