Biology subjects

Rozet, J.-M.

Publications and source records attributed to Rozet, J.-M..

3 recordsLinked to original sources

bioRxiv2025

Insights into the FOXE3 Transcriptional Network and Disease Mechanisms from the Investigation of a Regulatory Variant Driving Complex Microphthalmia

FOXE3 encodes a conserved, lens-specific transcription factor essential for eye development. Biallelic mutations in FOXE3 lead to a spectrum of ocular anomalies, from cataracts to complex microphthalmia (CM), with clinical severity correlating to genotype. In a CM case with a truncating mutation (p.Cys240*), we identified a regulatory variant (rv, rs745674596 G>A) 3 kb upstream of FOXE3. Mouse models harboring either the rv or a frameshift mutation were generated in homozygosity (Foxe3rv/rv, Foxe3-/-) and compound heterozygosity (Foxe3rv/Foxe3-). Phenotypic analysis revealed progressive severity: Foxe3rv/rv mice exhibited cataracts and anterior segment dysgenesis, Foxe3rv/Foxe3-displayed more severe anomalies, and Foxe3-/- mice consistently developed CM. These findings align with human genotype-phenotype relationships. Notably, a direct correlation between protein levels and ocular phenotype was observed, with no association to mRNA levels. In Foxe3-/- mice, CM resulted from early disorganization of the anterior lens epithelium, leading to degeneration and ocular involution. Transcription factor binding assays identified USF2 as a key regulator of FOXE3 expression, positioning USF2 as a promising candidate in ocular development and disease, enhancing our understanding of the FOXE3-related network. This study underscores the importance of integrated approaches to identify genetic variants and cis-regulatory elements, revealing a novel mechanism for microphthalmia through degeneration and involution.

genetics↗

bioRxiv2023

Modeling the critical MCOR-causing deletion in mouse unveils aberrant Sox21 expression in developing and adult iris and ciliary body, and implicates Tgfb2 in MCOR-associated glaucoma and myopia.

Congenital microcoria (MCOR) is a rare hereditary developmental defect of the iris dilator muscle, frequently associated with high axial myopia and high intraocular pressure (IOP) glaucoma. The condition is caused by submicroscopic rearrangements of chromosome 13q32.1. However, the mechanisms underlying the failure of iris development and the origin of associated features remain elusive. Here, we present a 3D architecture model of the 13q32.1 region, demonstrating that MCOR-related deletions consistently disrupt the boundary between two Topologically Associating Domains (TADs). Deleting the critical MCOR-causing region in mice reveals ectopic Sox21 expression precisely aligning with Dct, each located in one of the two neighbor TADs. This observation is consistent with the TADs boundary alteration and adoption of Dct regulatory elements by the Sox21 promoter. Additionally, we identify Tgfb2 as a target gene of SOX21 and show TGFB2 accumulation in the aqueous humor of a MCOR-affected subject. Accumulation of TGFB2 is recognized for its role in glaucoma and potential impact on axial myopia. Our results highlight the importance of SOX21-TGFB2 signaling in iris development and control of eye growth and IOP. Insights from MCOR studies may provide therapeutic avenues for this condition but also for glaucoma and high myopia conditions, affecting millions of people.

genetics↗

bioRxiv2023

Pharmacological cAMP stimulation via prostaglandin receptors rescues ciliary defects in CEP290-deficient patient and mouse models

The retinas sensitivity to light depends on the primary cilium of photoreceptors, known as the outer segment (OS). OS defects are a primary cause of inherited retinal dystrophies (IRDs) and can also indicate wider ciliary dysfunctions. One such IRD is Leber congenital amaurosis type 10 (LCA10), which occurs as a monosymptomatic retinal disease or the presenting symptom of syndromic ciliopathies within the Senior-Loken-Joubert-Meckel spectrum. LCA10 patients are born blind but retain dormant photoreceptors for decades, offering the potential for reactivation. AAV-based gene therapies for IRDs cannot accommodate the large CEP290 gene, prompting the search for innovative treatments. LCA10 is caused by mutations in CEP290, which plays a vital role in ciliation, similar to cAMP signaling. Utilizing fibroblasts displaying variable CEP290 mutations and associated ciliary defects, we show that exposure to Taprenepag, a specific PGE2 receptor agonist, substantially stimulated cAMP synthesis and consistently improved cilia formation and elongation. We also found that intraperitoneal injection of Taprenepag in mice reached the retina and slowed retinal degeneration, promoting OS formation, and improving light sensitivity in a Cep290 mutant mouse. These findings demonstrate the potential of Taprenepag to treat the CEP290-related visual dysfunction and suggest evaluation for other CEP290-related organ issues and ciliopathies.

genetics↗