Biology subjects

Marfany, G.

Publications and source records attributed to Marfany, G..

3 recordsLinked to original sources

bioRxiv2023

Specific photoreceptor cell fate pathways are differentially altered in NR2E3-associated diseases

Mutations in NR2E3 cause two retinal dystrophies with a distinct phenotype. NR2E3 encodes an orphan nuclear transcription factor that contributes to photoreceptor cell fate determination by repressing cone while activating rod genes. To dissect NR2E3 function, we performed scRNA-seq in the retinas of wild type and two different Nr2e3 mouse models that show phenotypes similar to patients carrying NR2E3 mutations. Our results reveal that rod and cone populations are not homogeneous and can be separated into different sub- classes. We identify a previously unreported cone pathway that generates hybrid cones that co-express both cone- and rod-related genes. In mutant retinas, this hybrid cone subpopulation is more abundant, as it includes a subpopulation of rods transitioning towards a cone cell fate. Hybrid photoreceptors with high misexpression of cone- and rod-related genes are prone to regulated necrosis. Overall, our results shed light on the role of NR2E3 in modulating photoreceptor differentiation towards cone and rod fates and explain how mutations in NR2E3 lead to different visual disorders in humans. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=196 SRC="FIGDIR/small/543550v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@bc8118org.highwire.dtl.DTLVardef@1bf5f72org.highwire.dtl.DTLVardef@11351f5org.highwire.dtl.DTLVardef@169e7df_HPS_FORMAT_FIGEXP M_FIG C_FIG SYNOPSISMutations in the gene encoding the retinal transcription factor NR2E3 cause two different inherited retinal dystrophies: retinitis pigmentosa and enhanced S-cone syndrome. O_LIscRNA-seq in retinas of wild type and two Nr2e3 mouse models reveal that rod and cone populations are not homogeneous and can be classified into different sub-classes. C_LIO_LIA previously unreported cone pathway that generates hybrid cones co- expressing both cone- and rod-related genes is identified. C_LIO_LIHybrid photoreceptors with high misexpression of cone- and rod-related genes are prone to regulated necrosis. C_LIO_LIExpression of rod and cone signature genes change in response to different NR2E3 mutations thus providing a frame to understand the molecular basis of distinct NR2E3-associated diseases. C_LI

genetics↗

bioRxiv2021

A novel Alex3/Gαq protein complex regulating mitochondrial dynamics, dendritic complexity, and neuronal survival

In neurons, mitochondrial dynamics and trafficking are essential to provide the energy required for neurotransmission and neuronal activity. Recent studies point to GPCR and G proteins as important regulators of mitochondrial dynamics and energy metabolism. Here we show that activation of Gq negatively regulates mitochondrial dynamics and trafficking in neurons. Gq interacts with the mitochondrial trafficking protein Alex3. By generating a CNS-specific armcx3 knock-out mouse line, we demonstrate that Alex3 is required for Gq effects on mitochondrial dynamics and trafficking, and dendritic growth. Armcx3-deficient mice present decreased OXPHOS complex and ER stress response protein levels, which correlate with increased neuronal death, motor neuron and neuromuscular synaptic loss, and severe motor alterations. Finally, we show that Alex3 disassembles from the Miro1/Gq complex upon calcium rise. These data uncover a novel Alex3/Gq complex that regulates neuronal mitochondrial dynamics and neuronal death and allows the control of mitochondrial functions by GPCRs.

cell biology↗

bioRxiv2020

Nr2e3 functional domain ablation by CRISPR-Cas9D10A identifies a new isoform and generates Retinitis Pigmentosa and Enhanced S-cone Syndrome models

Mutations in NR2E3 cause retinitis pigmentosa (RP) and enhanced S-cone syndrome (ESCS) in humans. This gene produces a large isoform encoded in 8 exons and a previously unreported shorter isoform of 7 exons, whose function is unknown. We generated two mouse models by targeting exon 8 of Nr2e3 using CRISPR/Cas9-D10A nickase. Allele {Delta}27 is an in-frame deletion of 27 bp that ablates the dimerization domain, whereas allele {Delta}E8 (full deletion of exon 8), produces only the short isoform that lacks the dimerization and repressor domains. The {Delta}27 mutant shows developmental alterations and a non-progressive electrophysiological dysfunction that resembles the ESCS phenotype. The {Delta}E8 mutant exhibits progressive retinal degeneration, as occurs in human RP patients. Interestingly, the mutant retinas show invaginations similar to fovea-like pits. Our mutants suggest a role of Nr2e3 as a cone-patterning regulator and provide valuable models for studying mechanisms of NR2E3-associated retinal dystrophies and evaluating potential therapies. O_FIG O_LINKSMALLFIG WIDTH=186 HEIGHT=200 SRC="FIGDIR/small/147785v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@1f5916forg.highwire.dtl.DTLVardef@11f1384org.highwire.dtl.DTLVardef@13a6cd2org.highwire.dtl.DTLVardef@be52b3_HPS_FORMAT_FIGEXP M_FIG C_FIG Highlights- Nr2e3 mouse models were generated by exon 8 deletion using CRISPR/Cas9 D10A nickase. - New Nr2e3 mRNA retaining intron 7 encodes a short protein expressed in adult retina. - Deletion of 9 aa of the NR2E3 dimerization domain causes enhanced S-cone syndrome. - Deletion of exon 8 produces a phenotype similar to Retinitis Pigmentosa in mouse.

genetics↗