Mariana Boroni

The female reproductive tract is essential for fertility, pregnancy, and overall health, yet many of its cellular components remain poorly defined. Recent advances in single-cell and spatial transcriptomics have begun to reveal this complexity, but inconsistent naming of cell types and states has limited the ability to compare findings across studies. To address this challenge, an international group of reproductive biologists and ontology experts collaborated to harmonize annotations within Cell Ontology, focusing on the ovary, fallopian tube, and uterus. Standardized terms are proposed for major epithelial, stromal, and germ cell populations, supported by marker gene sets and anatomical linkages. This framework provides a shared reference that can be used to harmonize existing datasets and guide annotation of future studies, enabling consistent classification of oocytes, granulosa, theca, luteal, epithelial, stromal, and immune cells across tissues. By establishing a unified taxonomy, this work lays the foundation for integrating datasets, supporting cross-tissue comparisons, and advancing the understanding of reproductive biology, health, and disease.

Background: Osteopontin is a glycophosphoprotein aberrantly expressed in several tumor types, which exhibits several isoforms generated by post-translational and post-transcriptional mechanisms, including alternative splicing. Among total osteopontin (tOPN), the osteopontin-c (OPN-c) splice variant has been the most explored with an oncogenic role described for a range of tumor types. Especially in ovarian cancer (OC) cells, OPN-c is found overexpressed, presenting both diagnostic and prognostic implications. Objective: In this review article, we aim to outline OPN-c roles in cancer, particularly in OC, in which it has been reported as a diagnostic biomarker. Methods: We used PubMed search, and experimental procedures were summarized at the Figure legends. Results: We identified cytoplasmic, perinuclear, and nuclear OPN-c in OC cells that overexpress this OPN splice variant. Moreover, we report that OPN-c splicing isoform is found highly expressed in endometrioid OC patients’ samples, compared to non-neoplastic ovarian tissues. Also, OPN-c expression levels have been associated with worse overall survival and worse progression-free survival in patients with both endometrioid and serous OC. Furthermore, OPN-c may be involved in a wide range of tumor features evoked by signaling pathways, such as AKT, ERK, and FAK. Conclusions: Therefore, a better comprehension of OPN-c roles in OC can further contribute to its application as a biomarker as well as a target for putative treatment strategies, especially those aiming to sensitize tumor cells to chemotherapeutic agents currently used in the OC treatment.

Adipose tissue (AT) is a complex connective tissue with a high relative proportion of adipocytes, which are specialized cells with the ability to store lipids in large droplets. AT is found in multiple discrete depots throughout the body, where it serves as the primary repository for excess calories. In addition, AT has an important role in functions as diverse as insulation, immunity and regulation of metabolic homeostasis. The Human Cell Atlas Adipose Bionetwork was established to support the generation of single-cell atlases of human AT as well as the development of unified approaches and consensus for cell annotation. Here, we provide a first roadmap from this bionetwork, including our suggested cell annotations for humans and mice, with the aim of describing the state of the field and providing guidelines for the production, analysis, interpretation and presentation of AT single-cell data.

Atrial fibrillation (AF) is more prevalent in patients with elevated interleukin (IL)-1β levels. Here we show that daily administration of IL-1β for 15 days sensitizes mice to AF, leading to fibrosis, accumulation of β-pleated sheet proteins in the left atrium, and systemic inflammation, resembling the pathophysiological changes observed in patients with AF. IL-1β administration creates a positive feedback loop, dependent on the IL-1 receptor (IL-1R) activity in cardiac resident macrophages. This results in increased caspase-1 maturation in the left atrium and elevated Il1b and Casp1 transcription in atrial macrophages. IL-1β treatment accelerated action potential and Ca²⁺ restitution in the left atrium, leading to action-potential shortening. This, along with increased caspase-1 maturation and IL-1R signaling, was essential for inducing AF. Lack of IL-1R in macrophages, but not cardiomyocytes, prevented IL-1β-induced AF sensitivity. By depleting recruited macrophages or deleting IL-1R specifically in cardiac resident macrophages, we further demonstrate that IL-1β/IL-1R signaling in these resident macrophages is responsible for increased AF susceptibility. These findings offer insights into the therapeutic potential of targeting IL-1β/IL-1R signaling in patients with AF and emphasize the importance of recognizing different underlying causes in this patient group.

SUMMARY: BRAF inhibitor-resistant melanomas (BRAFiR) acquire (epi)genetic and functional alterations that enable them to evade alternative treatments. Identifying these alterations is critical to advancing treatment strategies. Here, we explored the effect of Chk1 inhibition (Chk1i) on BRAFiR cells, revealing higher sensitivity compared to treatment-naïve cells both in vitro and in vivo . Using FUCCI-labeling and time-lapse microscopy, we show that S phase progression is required for Chk1i-induced cytotoxicity in BRAFiR cells, but not in treatment-naïve cells. Replication stress markers, including reduced BrdU incorporation and increased phospho-RPA and γH2AX, were exclusive to BRAFiR cells exposed to Chk1i. Untreated BRAFiR cells exhibited upregulated DNA replication genes, reduced progressing forks and increased origin firing, suggesting intrinsic replication changes. MAPK pathway reactivation in treatment-naïve cells mimicked BRAFiR traits, increasing sensitivity to Chk1i. These findings indicate that Chk1i exploits elevated replication stress specifically in BRAFiR, highlighting its therapeutic potential in overcoming MAPK inhibitor resistance in melanoma.

Antigen recognition by CD8+ T-cell receptors (TCR) is crucial for immune responses to pathogens and tumors. TCRs are cross-reactive, a single TCR can recognize multiple peptide-Human Leukocyte Antigen (HLA) complexes. The study of cross-reactivity can support the development of therapies focusing on immune modulation, such as the expansion of pre-existing T-cell clones to fight pathogens and tumors. The peptide-HLA (pHLA) surface has previously been used to identify TCR cross-reactivities. In the present work, we sought to perform a comprehensive analysis of peptide-HLA by selecting thousands of human and viral epitopes. We profit from established docking models to identify features from different spatial perspectives of HLA-A*02:01, explore similarities between self and non-self epitopes, and list potential cross-reactive epitopes of therapeutic interest. A total of 2631 unique epitopes from representative viral proteins or human proteins were modeled. We were able to demonstrate that cross-reactive CDR3 sequences from public databases recognize epitopes with similar electrostatic potential, charge, and spatial location. Using data from published studies that measured T-cell reactivity to mutated epitopes, we observed a negative correlation between epitope dissimilarity and T-cell activation. Most analysed cancer epitopes were more similar to self epitopes, yet we identified features distinguishing those more similar to viral antigens. Finally, we enumerated potential cross-reactivities between tumoral and viral epitopes and highlighted some challenges in their identification for therapeutic use. Moreover, the thousands of peptide-HLA complexes generated in our work constitute a valuable resource to study T-cell cross-reactivity.