Biology subjects

Oproescu, A.-M.

Publications and source records attributed to Oproescu, A.-M..

4 recordsLinked to original sources

bioRxiv2025

The Clearance of Human Cytomegalovirus Using CRISPR/Cas9 RNA Lipid Nanoparticles

Human cytomegalovirus (HCMV), a DNA virus, poses significant health risks to immunocompromised and immunosuppressed individuals and newborns. Clinical antiviral drugs like ganciclovir inhibit viral replication but have toxicities, are ineffective against drug-resistant strains, and cannot destroy HCMV DNA. CRISPR/Cas9 can cleave DNA, but has not been used therapeutically to target and degrade HCMV DNA in cells post-infection. We developed an all-in-one CRISPR/Cas9 RNA lipid nanoparticle (LNP) that clears established HCMV infections, permits rapid updating to combat resistance and is effective against multiple strains. Bioinformatic analyses identified essential, conserved viral genes as CRISPR/Cas9 targets. A delivery material screen revealed that antiviral activity was dependent on the ionizable lipid and LNP composition. Our lead formulation, {beta}N2-40, inhibited up to 93.5% of HCMV infection with a single treatment. Furthermore, multitargeting {beta}N2-40 LNPs demonstrated antiviral kinetics and a safety profile similar to ganciclovir, making it a compelling alternative to existing small-molecule antiviral drugs.

bioengineering↗

bioRxiv2024

NEUROG2 regulates a human-specific neurodevelopmental gene regulatory program

Unique hallmarks of human neocortical development include slower rates of neurogenesis and the establishment of an extracellular matrix-rich, outer-subventricular zone that supports basal neural progenitor cell expansion. How gene regulatory networks have evolved to support these human-specific neurodevelopmental features is poorly understood. Mining single cell data from cerebral organoids and human fetal cortices, we found that NEUROG2 expression is enriched in basal neural progenitor cells. To identify and purify NEUROG2-expressing cells and trace their short-term lineage, we engineered two NEUROG2-mCherry knock-in human embryonic stem cell lines to produce cerebral organoids. Transcriptomic profiling of mCherry-high organoid cells revealed elevated expression of PPP1R17, associated with a fast-evolving human-accelerated regulatory region, oligodendrocyte precursor cell and extracellular matrix-associated gene transcripts. Conversely, only neurogenic gene transcripts were enriched in mCherry-high cortical cells from Neurog2:mCherry knock-in mice. Finally, we show that Neurog2 is sufficient to induce Ppp1r17, which slows human neural progenitor cell division, and Col13a1, an extracellular matrix gene, in P19 cells. NEUROG2 thus regulates a human neurodevelopmental gene regulatory program implicated in supporting a pro-proliferative basal progenitor cell niche and tempering the neurogenic pace. SUMMARY STATEMENTTranscriptomic analyses of NEUROG2-mCherry knock-in human embryonic stem cell-derived cerebral organoids reveal a link between NEUROG2 and extracellular matrix remodeling during human cortical development.

developmental biology↗

bioRxiv2023

Proneural genes form a combinatorial code to diversify neocortical neural progenitor cells

Neocortical neural progenitor cells (NPCs) are molecularly heterogeneous, yet the genes that confer distinct neuronal morphologies and connectivities during development are poorly understood. Here, we determined that a proneural gene combinatorial code diversifies cortical NPCs. By mining scRNA-seq data from murine embryonic and early postnatal cortices and generating trajectory inference models, we found that Neurog2 is predominant, and is transiently co-expressed with Ascl1 and/or Neurog1 during an apical-to-basal NPC transition state in NPCs with early pseudotime identities. To assess whether proneural gene pairs confer distinct properties, we first used Neurog2/Ascl1 reporter mice expressing unique reporters, revealing that NPCs have distinct cell division modes and cell cycle dynamics dependent on their proneural gene profile. To assess Neurog2/Neurog1 interactions, we used double knock-out mice and novel split-Cre transgenics crossed to a Rosa-diptheria-toxin-A line to delete double+ cells, showing Neurog1/Neurog2 are specifically required to generate early-born neurons and to maintain NPCs. Finally, in silico mutation of a cortical Neurog2-gene regulatory network and validation using Neurog1/Neurog2 mutant and deleter mice, identified Bclllb and Nhlh2, expressed in early-born neurons, as dependent on Neurog1/Neurog2. Our data explains how proneural genes act combinatorically to diversify gene regulatory networks, thereby lineage restricting NPCs and creating cortical neuronal diversity.

developmental biology↗

bioRxiv2020

Proneural genes define ground state rules to regulate neurogenic patterning and cortical folding

Transition from smooth, lissencephalic brains to highly-folded, gyrencephalic structures is associated with neuronal expansion and breaks in neurogenic symmetry. Here we show that Neurog2 and Ascl1 proneural genes regulate cortical progenitor cell differentiation through cross-repressive interactions to sustain neurogenic continuity in a lissencephalic rodent brain. Using in vivo lineage tracing, we found that Neurog2 and Ascl1 expression defines a lineage continuum of four progenitor pools, with double+ progenitors displaying several unique features (least lineage-restricted, complex gene regulatory network, G2 pausing). Strikingly, selective killing of double+ progenitors using split-Cre;Rosa-DTA transgenics breaks neurogenic symmetry by locally disrupting Notch signaling, leading to cortical folding. Finally, consistent with NEUROG2 and ASCL1 driving discontinuous neurogenesis and folding in gyrencephalic species, their transcripts are modular in folded macaque cortices and pseudo-folded human cerebral organoids. Neurog2/Ascl1 double+ progenitors are thus Notch-ligand expressing niche cells that control neurogenic periodicity to determine cortical gyrification. HIGHLIGHTSO_LINeurog2 and Ascl1 expression defines four distinct transitional progenitor states C_LIO_LIDouble+ NPCs are transcriptionally complex and mark a lineage branch point C_LIO_LIDouble+ NPCs control neurogenic patterning and cortical folding via Notch signaling C_LIO_LINeurog2 and Ascl1 expression is modular in folded and not lissencephalic cortices C_LI eTOC BLURBEmergence of a gyrencephalic cortex is associated with a break in neurogenic continuity across the cortical germinal zone. Han et al. identify a pool of unbiased neural progenitors at a lineage bifurcation point that co-express Neurog2 and Ascl1 and produce Notch ligands to control neurogenic periodicity and cortical folding.

developmental biology↗