Biology subjects

Antunes, L.

Publications and source records attributed to Antunes, L..

4 recordsLinked to original sources

bioRxiv2023

Association of an estrogen-sensitive Pax1-Col11a1-Mmp3 signaling axis with adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a common and progressive spinal deformity in children that exhibits striking sexual dimorphism, with girls at more than five-fold greater risk of severe disease compared to boys. Despite its medical impact, the molecular mechanisms that drive AIS are largely unknown. We previously defined a female-specific AIS genetic risk locus in an enhancer near the PAX1 gene. Here we sought to define the roles of PAX1 and newly-identified AIS-associated genes in the developmental mechanism of AIS. In a genetic study of 10,519 individuals with AIS and 93,238 unaffected controls, significant association was identified with a variant in COL11A1 encoding collagen (1) XI (rs3753841; NM_080629.2_c.4004C>T; p.(Pro1335Leu); P=7.07e-11, OR=1.118). Using CRISPR mutagenesis we generated Pax1 knockout mice (Pax1-/-). In postnatal spines we found that PAX1 and collagen (1) XI protein both localize within the intervertebral disc (IVD)-vertebral junction region encompassing the growth plate, with less collagen (1) XI detected in Pax1-/- spines compared to wildtype. By genetic targeting we found that wildtype Col11a1 expression in costal chondrocytes suppresses expression of Pax1 and of Mmp3, encoding the matrix metalloproteinase 3 enzyme implicated in matrix remodeling. However, this suppression was abrogated in the presence of the AIS-associated COL11A1P1335L mutant. Further, we found that either knockdown of the estrogen receptor gene Esr2, or tamoxifen treatment, significantly altered Col11a1 and Mmp3 expression in chondrocytes. We propose a new molecular model of AIS pathogenesis wherein genetic variation and estrogen signaling increase disease susceptibility by altering a Pax1-Col11a1-Mmp3 signaling axis in spinal chondrocytes.

genetics↗

bioRxiv2021

Intronization enhances expression of S-protein and other transgenes challenged by cryptic splicing

The natural habitat of SARS-CoV-2 is the cytoplasm of a mammalian cell where it replicates its genome and expresses its proteins. While SARS-CoV-2 genes and hence its codons are presumably well optimized for mammalian protein translation, they have not been sequence optimized for nuclear expression. The cDNA of the Spike protein harbors over a hundred predicted splice sites and produces mostly aberrant mRNA transcripts when expressed in the nucleus. While different codon optimization strategies increase the proportion of full-length mRNA, they do not directly address the underlying splicing issue with commonly detected cryptic splicing events hindering the full expression potential. Similar splicing characteristics were also observed in other transgenes. By inserting multiple short introns throughout different transgenes, significant improvement in expression was achieved, including >7-fold increase for Spike transgene. Provision of a more natural genomic landscape offers a novel way to achieve multi-fold improvement in transgene expression.

genetics↗

bioRxiv2021

Effect of hydroxyapatite microspheres, amoxicillin-hydroxyapatite and collagen-hydroxyapatite composites on human dental pulp-derived mesenchymal stem cells

The aim of this study was to evaluate the in vitro behavior of human dental pulp mesenchymal stem cells (hDPSCs) cultured on scaffolds of three hydroxyapatite-based materials: hydroxyapatite microspheres [HAp]; amoxicillin-hydroxyapatite composite [Amx-HAp]; and collagen-hydroxyapatite composite [Col-HAp]. These hydroxyapatites (HAps) were synthesized through three methods: microwave hydrothermal, hydrothermal reactor (teflon pouches), and precipitation, respectively. We performed an in vitro experimental study using dental pulp stem cells obtained from samples of third molars and characterized by immunophenotypic analysis. Cells were cultured on scaffolds with osteogenic differentiation medium and were maintained for 21 days. Cytotoxicity analysis and migration assay of hDPSCs were evaluated. Each experiment was performed in triplicate. Data analysis was performed using Kruskal-Wallis test and Dunns post-hoc test. After 21 days of induction, no differences in genes expression were observed. hDPSCs highly expressed the collagen IA and the osteonectin at the mRNA, which indicated these genes plays an important role in odontogenesis regardless of induction stimulus. Cytotoxicity assay using hDPSCs demonstrated that Col-HAp group presented a number of non-viable cells statistically lower than the control group (p=0.03). In the migration assay after 24h, biomaterials HAp, Amx-HAp, and Col-HAp revealed the same migration behavior for hDPSCs observed to the positive control. Col-HAp also provided a statistically significant higher migration of hDPSCs than HAp (p=0.02). The migration results in 48h for HAp, Amx-HAp, and Col-HAp was intermediate from those achieved by control groups. There was no statistical difference between positive control and Col-HAp (p>0.05). In general, Col-HAp scaffold showed better features for these dynamic parameters of cell viability and cell migration capacities for hDPSCs, leading to suitable adhesion, proliferation, and differentiation of this osteogenic lineage. These data present high clinical importance because Col-HAp can be used in a wide variety of therapeutic areas, including ridge preservation, minor bone augmentation, and periodontal regeneration.

cell biology↗

bioRxiv2017

Establishment In Culture Of Expanded Potential Stem Cells

Mouse embryonic stem cells are derived from in vitro explantation of blastocyst epiblasts1,2 and contribute to both the somatic lineage and germline when returned to the blastocyst3 but are normally excluded from the trophoblast lineage and primitive endoderm4-6. Here, we report that cultures of expanded potential stem cells (EPSCs) can be established from individual blastomeres, by direct conversion of mouse embryonic stem cells (ESCs) and by genetically reprogramming somatic cells. Remarkably, a single EPSC contributes to the embryo proper and placenta trophoblasts in chimeras. Critically, culturing EPSCs in a trophoblast stem cell (TSC) culture condition permits direct establishment of TSC lines without genetic modification. Molecular analyses including single cell RNA-seq reveal that EPSCs share cardinal pluripotency features with ESCs but have an enriched blastomere transcriptomic signature and a dynamic DNA methylome. These proof-of-concept results open up the possibility of establishing cultures of similar stem cells in other mammalian species.

developmental biology↗