Biology subjects

Abdelhady, A. W.

Publications and source records attributed to Abdelhady, A. W..

3 recordsLinked to original sources

bioRxiv2026

A transient epithelial plasticity state defines the developmental window for uterine gland specification

Uterine gland development and function is essential for reproduction and womens health, yet the epithelial cell states and signaling interactions that govern gland fate specification are not well understood. Here, integration of single cell and spatial transcriptomics with organoid culture, lineage tracing, and genetic and hormonal perturbation models were used to define mechanisms regulating postnatal uterine epithelial differentiation. A developmentally restricted epithelial plasticity state was identified that precedes luminal and glandular cell lineage segregation and is accompanied by dynamic reorganization of stromal-epithelial communication during uterine differentiation. Pseudotime analysis revealed progressive acquisition of gland-associated programs, including forkhead box A2 (Foxa2), retinoic acid metabolic genes, and epithelial estrogen receptor alpha (Esr1) expression. Functional studies revealed that ESR1 acquisition and retinoic acid signaling suppress the multilayered organoid phenotype associated with epithelial plasticity, thereby promoting epithelial specification and lineage commitment. Moreover, neonatal hormonal perturbation of adenogenesis and conditional deletion of Foxa2 abolished this organoid phenotype. Together, these findings demonstrate that ESR1 acquisition, retinoic acid signaling and FOXA2-dependent glandular differentiation each restrict a transient epithelial plasticity state, coupling the loss of developmental plasticity to the emergence of the glandular lineage.

developmental biology↗

bioRxiv2025

Flexible oocyte manipulation with delayed maturation and improved SCNT efficiency using induced pluripotent stem cells

Somatic cell nuclear transfer (SCNT) remains inefficient, limiting its practical use in cattle reproduction and research. This study investigated two complementary strategies to enhance handmade cloning (HMC): (1) holding bovine oocytes overnight and delaying maturation to enable a second round of SCNT and (2) using bovine-induced pluripotent stem cells (biPSCs) as donor nuclei to enhance developmental competence. Bovine oocytes were subjected to either conventional in vitro maturation (CONV; 20 h) or delayed maturation using a holding medium for 20 h before CONV (HOLD). Matured oocytes were used for SCNT, parthenogenetic activation (PA), or in vitro fertilization (IVF) as controls. Handmade SCNT embryos were reconstructed using fibroblasts or biPSCs as donors, activated, and cultured for 7 days. Results showed no significant differences between CONV and HOLD groups in oocyte maturation, recovery after stripping, survival after zona removal, or cleavage and blastocyst development after SCNT. Fusion rates using fibroblasts were comparable between groups (42.6{+/-}6.0% vs. 50.3{+/-}9.8%), with biPSCs showing significantly higher fusion rates in CONV group (85.7{+/-}8.2% vs. 50.5{+/-}8.8%, P<0.05). Among fused embryos, biPSCs produced higher blastocyst rates (33.3{+/-}16.7%) compared with fibroblast donors (21.9{+/-}12.6%, P<0.05). Across all reconstructed embryos, cleavage and blastocyst development were also greater with biPSCs (odds ratios 3.4 and 2.7 respectively). These findings indicate that delaying maturation offers flexible timing for SCNT without compromising competence. Moreover, biPSCs enhance embryo developmental outcomes, supporting their use as superior donor cells for advancing cloning efficiency and applications in reproductive biotechnology.

developmental biology↗

bioRxiv2023

Ice formation and its elimination in cryopreservation of bovine oocytes

Damage from ice and potential toxicity of ice-inhibiting cryoprotective agents (CPAs) are key issues in assisted reproduction using cryopreserved oocytes and embryos. We use synchrotron-based time-resolved x-ray diffraction and tools from protein cryocrystallography to characterize ice formation within bovine oocytes after cooling at rates between [~]1000 {degrees}C/min and [~]600,000{degrees}C /min and during warming at rates between 20,000 and 150,000 {degrees}C /min. Maximum crystalline ice diffraction intensity, maximum ice volume, and maximum ice grain size are always observed during warming. All decrease with increasing CPA concentration, consistent with the decreasing free water fraction. With the cooling rates, warming rates and CPA concentrations of current practice, oocytes may show no ice after cooling but always develop substantial ice fractions on warming, and modestly reducing CPA concentrations causes substantial ice to form during cooling. With much larger cooling and warming rates achieved using cryocrystallography tools, oocytes soaked as in current practice remain essentially ice free during both cooling and warming, and when soaked in half-strength CPA solution oocytes remain ice free after cooling and develop small grain ice during warming. These results clarify the roles of cooling, warming, and CPA concentration in generating ice in oocytes, establish the character of ice formed, and suggest that substantial further improvements in warming rates are feasible. Ice formation can be eliminated as a factor affecting post-thaw oocyte viability and development, allowing other deleterious effects of the cryopreservation cycle to be studied, and osmotic stress and CPA toxicity reduced. Significance StatementCryopreservation of oocytes and embryos is critical in assisted reproduction of humans and domestic animals and in preservation of endangered species. Success rates are limited by damage from crystalline ice, toxicity of cryoprotective agents (CPAs), and damage from osmotic stress. Time-resolved x-ray diffraction of bovine oocytes shows that ice forms much more readily during warming than during cooling, that maximum ice fractions always occur during warming, and that the tools and large CPA concentrations of current protocols can at best only prevent ice formation during cooling. Using tools from cryocrystallography that give dramatically larger cooling and warming rates, ice formation can be completely eliminated and required CPA concentrations substantially reduced, expanding the scope for species-specific optimization of post-thaw reproductive outcomes.

biophysics↗