Biology subjects

Strobl-Mazzulla, P. H.

Publications and source records attributed to Strobl-Mazzulla, P. H..

6 recordsLinked to original sources

bioRxiv2025

Core microRNAs regulate neural crest delamination and condensation in the developing trigeminal ganglion

Cranial neural crest cells (NCCs) undergo dynamic processes during embryonic development, including delamination from the neural tube by epithelial-to-mesenchymal transition (EMT), migration to the periphery, condensation via mesenchymal-to-epithelial transition (MET) and differentiation into structures like the trigeminal ganglion. Here, we identify and characterize the function of a core set of miRNAs involved in these transitions during the formation of the trigeminal ganglion in the chick embryo. We further identify putative targets of miRNAs involved in neural crest EMT and MET. Notably, introducing MET-involved miRNAs into trunk NCCs endows these cells with the ability to condense and differentiate into neurons in vivo in a manner reminiscent of cranial rather than trunk NCCs. Our findings shed light on the intricate regulatory networks governing NCC behavior, positioning miRNAs as key regulatory elements required for migratory transitions and axial level specific differentiation capabilities.

developmental biology↗

bioRxiv2025

Targeting histone acetylation to overcome drug resistance in the parasite Trichomonas vaginalis

Resistance to antimicrobial drugs is a major global health challenge, yet the regulatory mechanisms underlying resistance phenotypes remain incompletely understood. In particular, whether epigenetic processes contribute to antimicrobial resistance in microbial eukaryotes is largely unexplored. Here, we show that epigenetic regulation plays a central role in modulating metronidazole resistance in Trichomonas vaginalis, the causative agent of the most common non-viral sexually transmitted infection. Pharmacological inhibition of histone deacetylases restores drug sensitivity in a highly resistant clinical isolate, markedly reducing the minimum inhibitory concentration. Integrative transcriptomic reveal widespread transcriptional reprogramming associated with activation of pathways involved in redox metabolism, transcriptional regulation, and stress responses. Chromatin profiling demonstrates that increased H3K9 acetylation is strongly associated with transcriptional activation. Upon TSA treatment, increased H3K9 acetylation is observed at promoters and gene bodies of genes that may be associated with MTZ resistance. By combining epigenetic perturbation with comparative transcriptomics across multiple strains, we identify a set of genes that are epigenetically silenced in resistant parasites that are constitutively expressed in sensitive backgrounds. Functional re-expression of two candidates, thioredoxin reductase and a Myb-like transcription factor (Myb6), significantly reduces resistance, establishing a direct link between epigenetic regulation and drug sensitivity. Together, our findings uncover a reversible, chromatin-based mechanism underlying antimicrobial resistance in a protozoan parasite and highlight epigenetic reprogramming as a potential therapeutic strategy. More broadly, this work suggests that epigenetic regulation may represent a general and previously underappreciated layer of control over drug resistance in microbial eukaryotes.

microbiology↗

bioRxiv2023

miR-137 conferred robustness to the territorial restriction of the neural plate border

The neural plate border (NPB) of vertebrate embryos segregated from the neural plate (NP) and epidermal regions, and comprised an intermingled group of progenitors with multiple fate potential. Recent studies have shown that during the gastrula stage, TFAP2A acts as a pioneer factor in remodeling the epigenetic landscape required to activate components of the NPB induction program. Here we show that Tfap2a has two highly conserved binding sites for miR-137 and both display a reciprocal expression pattern at the NPB and NP respectively. In addition, ectopic miR-137 expression reduced TFAP2A, whereas its functional inhibition expanded their territorial distribution overlapping with PAX7. Furthermore, we demonstrated that loss of the de novo DNA methyltransferase DNMT3A expanded miR-137 expression to the NPB. Bisulfite sequencing showed a significantly higher level of non-canonical CpH methylation at the promoter of miR-137 when we compared NPB and NP samples. Our finding shows that miR-137 contributes to the robustness of NPB territorial restriction in vertebrate development.

developmental biology↗

bioRxiv2023

Extracellular vesicle-localized miR-203 mediates neural crest-placode communication required for trigeminal ganglia formation

While interactions between neural crest and placode cells are critical for the proper formation of the trigeminal ganglion, the mechanisms underlying this process remain largely uncharacterized. Here, we show that the microRNA-(miR)203, whose epigenetic repression is required for neural crest migration, is reactivated in coalescing and condensing trigeminal ganglion cells. Overexpression of miR-203 induces ectopic coalescence of neural crest cells and increases ganglion size. Reciprocally, loss of miR-203 function in placode, but not neural crest, cells perturbs trigeminal ganglion condensation. Demonstrating intercellular communication, overexpression of miR-203 in the neural crest in vitro or in vivo represses a miR-responsive sensor in placode cells. Moreover, neural crest-secreted extracellular vesicles (EVs), visualized using pHluorin-CD63 vector, become incorporated into the cytoplasm of placode cells. Finally, RT-PCR analysis shows that small EVs isolated from condensing trigeminal ganglia are selectively loaded with miR-203. Together, our findings reveal a critical role in vivo for neural crest-placode communication mediated by sEVs and their selective microRNA cargo for proper trigeminal ganglion formation. SIGNIFICANCE STRATEMENTCellular communication during early development plays a critical role. In this study, we demonstrate a unique role for a microRNA in cell-cell communication between the neural crest (NC) and placode cells (PC) during trigeminal ganglia (TG) formation. By utilizing loss and gain of function experiments in vivo, we demonstrate a requirement for miR-203 during cellular condensation to form the TG. We revealed that NC produces extracellular vesicles, selectively carrying miR-203, which is then taken up by the PC and regulates a sensor vector exclusively expressed in the placode. Taken together, our findings reveal a critical role in TG condensation for miR-203, produced by post-migratory NC and taken up by PC via extracellular vesicles.

developmental biology↗

bioRxiv2019

Exploring the link between adenine DNA methylation and 3D genome organization in the parasite Trichomonas vaginalis

Trichomonas vaginalis is a common sexually transmitted parasite that colonizes the human urogenital tract causing infections that range from asymptomatic to highly inflammatory. Recent works have highlighted the importance of histone modifications in the regulation of transcription and parasite pathogenesis. However, the nature of DNA methylation in the parasite remains unexplored. Using a combination of immunological techniques and UHPLC, we analyzed the abundance of DNA methylation in strains with differential pathogenicity demonstrating that N6-methyladenine (6mA), and not 5-methylcytosine (5mC), is the main DNA methylation mark in T. vaginalis. Genome-wide distribution of 6mA reveals that this mark is enriched at intergenic regions, with a preference for certain super-families of DNA transposable elements. We show that 6mA in T. vaginalis is associated with silencing when present on genes. Interestingly, bioinformatics analysis revealed the presence of transcriptionally active or repressive intervals flanked by 6mA-enriched regions and results from chromatin conformation capture (3C) experiments suggest these 6mA flanked regions are in close spatial proximity. These associations were disrupted when parasites were treated with the demethylation activator ascorbic acid. This finding revealed a new role for 6mA in modulating 3D chromatin structure and gene expression in this divergent member of the Excavata.\n\nSIGNIFICANCE STATEMENTTrichomonas vaginalis causes the most common non-viral sexually transmitted infection yet little is known about the regulation of gene expression in this eukaryotic parasite. We demonstrate that N6-methyladenine (6mA) is the main methylation mark in the T. vaginalis genome. 6mA is widespread in DNA of eubacterial genera, but uncommon in genomes of most eukaryotes. Examination of the genome-wide distribution of 6mA reveals a preference for intergenic regions. Transcriptionally active or repressive intervals are found to be flanked by 6mA-enriched regions and data suggest 6mA flanked regions are in close 3D spatial proximity. Our findings describe for the first time the presence of DNA methylation in T. vaginalis and reveal a new role for 6mA in modulating 3D chromatin architecture.

microbiology↗

bioRxiv2018

Epigenetic inactivation of miR-203 as a key step in neural crest epithelial-to-mesenchymal transition

miR-203 is a tumor-suppressor microRNA with known functions in cancer metastasis. Here, we explore its normal developmental role in the context of neural crest development. As neural crest cells undergo an epithelial-to-mesenchymal transition to emigrate from the neural tube, miR-203 displays a reciprocal expression pattern with key regulators of neural crest delamination, Phf12 and Snail2, and interacts with their 3UTRs. Ectopic maintenance of miR-203 inhibits neural crest migration, whereas its functional inhibition using a \"sponge\" vector promotes premature neural crest delamination. Bisulfite sequencing further shows that epigenetic repression of miR-203 is mediated by the de novo DNA methyltransferase DNMT3B, whose recruitment to regulatory regions on the miR-203 locus is directed by SNAIL2 in a negative feedback loop. These findings reveal an important role for miR-203 in an epigenetic-microRNA regulatory network that influences the timing of neural crest delamination.\n\nSummary statementThe EMT is a highly conserved process, involving similar levels of regulation in both neural crest and cancer cells. Our work shows an epigenetic-miRNA-gene regulatory circuit, conserved in cancer, which controls the timing of neural crest EMT as well.

developmental biology↗