Biology subjects

Colin, E.

Publications and source records attributed to Colin, E..

3 recordsLinked to original sources

bioRxiv2026

ARID5B mutations cause a neurodevelopmental syndrome with neuroinflammation episodes

Genetic disorders affecting the epigenetic machinery constitute a major group of neurodevelopmental conditions. Pathogenic variants in several ARID transcription factors--particularly ARID1A, ARID1B, and ARID2--cause Coffin-Siris syndromes, all characterized by intellectual disability (ID). These genes encode core subunits of the BRG1/BRM-associated factor (BAF) chromatin remodeling complex. In contrast, ARID family members that function in other regulatory complexes have remained largely unexplored in neurodevelopmental disease. Here, we identify 29 individuals carrying heterozygous ARID5B variants, of which 24 (83%) introduce premature termination codons in the exceptionally long final exon, one affects the exon 9 splice donor site, and four are missense variants in conserved domains within the N-terminal half of the protein. Using a CRISPR-Cas9 knock-in mouse model harboring the p.Q522Ter variant, together with in vitro assays, we investigated the functional consequences of C-terminal ARID5B truncations. All affected individuals presented with global developmental delay or ID--most commonly mild--and frequent speech and language impairment. Recurrent features included kidney malformations, behavioral difficulties, and recurrent infections of the respiratory and urinary tracts. Two individuals experienced central nervous system inflammation, and two infants presented with persistent pulmonary hypertension. Remarkably, 19 of 29 variants (66%) cluster within the first quarter of exon 10, are de novo, and escape nonsense-mediated mRNA decay (NMD), which we confirmed for two variants affecting seven individuals. Variants outside this region were inherited. Heterozygous mice exhibited developmental and behavioral abnormalities, while homozygous mutations was perinatally lethal. Truncations and a small deletion within a predicted nuclear localization signal (NLS) caused cytosolic mislocalization of ARID5B, whereas the isolated C-terminal half retained nuclear localization, suggesting an independent distal NLS. Collectively, these findings define ARID5B-related neurodevelopmental disorder as a distinct clinical entity and reveal how disruption of specific ARID5B domains impacts protein localization, mammalian development, immune and neurobehavioral function. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/698931v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@158e8d9org.highwire.dtl.DTLVardef@1f014dorg.highwire.dtl.DTLVardef@18e6e7forg.highwire.dtl.DTLVardef@1f886e9_HPS_FORMAT_FIGEXP M_FIG C_FIG

genetics↗

bioRxiv2025

Laser Speckle Orthogonal Contrast Imaging Calibration by Replicating Red Blood Cells Scattering Statistics with a Moving Reference Diffuser

Recent studies have proposed improving Laser Speckle Contrast Imaging (LSCI) by using polarimetric filtering to isolate multiply scattered photons from moving red blood cells (RBCs), an approach referred to as Laser Speckle Orthogonal Contrast Imaging (LSOCI). This reliance on multiple scattering enables the development of a calibration method based on a moving reference sample, chosen to generate dynamic circular Gaussian speckle fields that replicate the statistical properties of RBC scattering in both intensity and the distribution of polarization states. Assuming that multiply scattered photons from both RBCs and the reference sample exhibit a homogeneous distribution of polarization states over the Poincare sphere, the proposed calibration links in vivo speckle contrast reduction in a bijective manner to an equivalent speed of the reference sample. We demonstrate that this equivalent-velocity metric yields consistent in vivo measurements across distinct instruments despite the use of different laser spectral widths, thereby providing a standardized and transferable means to quantify microcirculation activity.

biophysics↗

bioRxiv2025

Loss of CTLH component MAEA impairs DNA repair and replication and leads to developmental delay

Ubiquitin E3 ligases play crucial roles in the DNA damage response (DDR) by modulating the turnover, localization, activation, and interactions of DDR and DNA replication proteins. To gain further insight into how the ubiquitin system regulates the DDR, we performed a CRISPR-Cas9 knockout screen focused on E3 ligases and related proteins with the DNA topoisomerase I inhibitor, camptothecin. This uncovered the CTLH ubiquitin E3 ligase complex -- and particularly one of its core subunits, MAEA -- as a critical regulator of the cellular response to single-ended DNA double-strand breaks (seDSBs) and replication stress. In tandem, we identified patients with variants in MAEA who present with neurodevelopmental deficits including global developmental delay, dysmorphic facial features, brain abnormalities, intellectual disability, and abnormal movement. Analysis of patient-derived cell lines and mutation modeling reveal an underlying defect in HR-dependent DNA repair and replication fork restart as a likely cause of disease. We propose that MAEA dysfunction hinders DNA repair by reducing the efficiency of RAD51 loading at sites of DNA damage, which compromises genome integrity and cell division during development.

genetics↗