Biology subjects

Vainio, S. J.

Publications and source records attributed to Vainio, S. J..

6 recordsLinked to original sources

bioRxiv2026

Evidence for early kidney vasculature development by vasculogenesis and angiogenesis based on advanced in vivo chimeric model and depletion of CD31+/CD146+ intrinsic endothelial progenitors

Kidney diseases are a significant health concern worldwide, with a growing demand for fundamental treatments, such as generation of transplantable organs from programmed cells. The generation of kidney organoids has led to significant advances in disease modeling. However, failure to establish a robust endothelial vasculature network in kidney organoids remains a barrier to oxygen support and gas exchange in renal tissue engineering. We targeted the development of early kidney vasculature system by advancing the classic mouse embryonic kidney organ culture and organoid model system by introducing a novel mini reservoir setup. The method improved integration with the highly vascularized chicken Chorion Allantois Membrane (CAM), enabling host blood flow to developing kidney organoids. We examined the origin and role of the CD31+ endothelial cells (ECs) and their CD146+ progenitors by applying a dissociated embryonic kidney approach. This enabled selected depletion of specific cell populations, followed by regeneration of the kidney organ primordia by reaggregation and placement on the CAM to assess organogenesis. The cell lineage and fate tracing with constitutively labelled cells revealed that the intrinsic endothelial CD146+ progenitor and those of CD31+ ECs in the kidney initiating organogenesis established the kidney vasculature. If the intrinsic EC progenitors were depleted, the mouse glomerular vascularization was rescued by the CAM derived ECs.

developmental biology↗

bioRxiv2026

Cloudberry-derived nanovesicles: in vitro functional effects in skin cell models and characterization of molecular cargo

Cloudberry (Rubus chamaemorus L.)-derived nanovesicles (NVs) represent a promising but still poorly characterized class of plant-derived vesicles with potential relevance for skin-related applications. Here, we isolated cloudberry fruit-derived NVs and investigated their physicochemical and molecular properties, cellular uptake, cytocompatibility, and functional effects in human dermal fibroblasts (HDF) and HaCaT keratinocytes. Nanoparticle tracking analysis and transmission electron microscopy confirmed a nanosized vesicle preparation with characteristic round morphology, while protein quantification supported reproducible isolation of NV-associated material. In vitro, cloudberry NVs showed concentration-dependent effects on cell viability and proliferation, with lower doses being better tolerated. Labelled NVs were internalized by both HDF and HaCaT cells in a time-dependent manner. Under oxidative stress conditions, cloudberry NVs reduced H2O2-induced senescence-associated {beta}-galactosidase staining in HDFs and exerted cytoprotective effects in both cell lines, alongside measurable cell-free antioxidant activity in the DPPH assay. In scratch wound-healing assays, cloudberry NVs modulated wound closure in a dose-dependent manner, with the lowest tested concentration showing the most favorable response. UHPLC-MS/MS-based proteomics and metabolomics further indicated the presence of diverse secondary metabolites and stress-related protein cargo. Together, these results support the view that cloudberry-derived NVs are biologically active plant nanovesicles with potential utility in skin-related regenerative applications. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=126 SRC="FIGDIR/small/741293v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@c9094dorg.highwire.dtl.DTLVardef@81a1b5org.highwire.dtl.DTLVardef@9fafe2org.highwire.dtl.DTLVardef@1d421d3_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2022

Unraveling the principles of mammary gland branching morphogenesis

Branching morphogenesis is a characteristic feature of many essential organs such as the lung, kidney, and most glands, and the net result of two tissue behaviors: branch point initiation and elongation. Each branched organ has a distinct architecture customized to its physiological function, but how patterning occurs in these ramified tubular structures is a fundamental problem of development. Here we use quantitative 3D morphometrics, time-lapse imaging, manipulation of ex vivo cultured embryonic organs, and mice deficient in the planar cell polarity component Vangl2 to address this question in the developing mammary gland. Our results show that the embryonic epithelial trees are highly complex in topology owing to the flexible use of two distinct modes of branch point initiation: lateral branching and tip bifurcation. This non-stereotypy was contrasted by the remarkably constant average branch frequency indicating a ductal growth-invariant, yet stochastic propensity to branch. The probability to branch was malleable and could be tuned by manipulating the Fgf10 and Tgf-{beta}1 pathways. Finally, our in vivo and ex vivo time-lapse imaging suggested the involvement of tissue rearrangements in mammary branch elongation.

developmental biology↗

bioRxiv2022

FGF8 induces chemokinesis and regulates condensation of mouse nephron progenitor cells

Kidneys develop via iterative branching of the ureteric epithelial tree and subsequent nephrogenesis at the branch points. Nephrons form in the cap mesenchyme as the metanephric mesenchyme (MM) condenses around the epithelial ureteric buds (UBs). Previous work demonstrated that FGF8 is important for the survival of nephron progenitor cells (NPCs), and early deletion of Fgf8 leads to the cessation of nephron formation, which results in post-natal lethality. We now reveal a novel function of FGF8. By combining transgenic mouse models, quantitative imaging assays, and data-driven computational modelling, we show that FGF8 has a strong chemokinetic effect and that this chemokinetic effect is important for the condensation of NPCs to the UB. The computational model shows that the motility must be lower close to the UB to achieve NPC attachment. We conclude that the FGF8 signalling pathway is crucial for the coordination of NPCs behaviour to the UB. Chemokinetic effects have been described also for other FGFs and may be relevant more generally for the formation of mesenchymal condensations.

developmental biology↗

bioRxiv2020

PKA drives paracrine crisis and WNT4-dependent testis tumor in Carney complex

Large Cell Calcifying Sertoli Cell Tumors (LCCSCTs) are among the most frequent lesions occurring in Carney complex (CNC) male patients. Although they constitute a key diagnostic criterion for this rare multiple neoplasia syndrome resulting from inactivating mutations of the tumor suppressor PRKAR1A leading to unrepressed PKA activity, the LCCSCT pathogenesis and origin remain elusive. Mouse models targeting Prkar1a inactivation in all somatic populations or separately in each cell type were generated to decipher the molecular and paracrine networks involved in the CNC testis lesion induction. We demonstrate that Prkar1a mutation is required in both stromal and Sertoli cells for the occurrence of LCCSCT. Integrative analyses comparing transcriptomic, immunohistological data and phenotype of mutant mouse combinations led to understand the human LCCSCT pathogenesis and demonstrated unprecedented PKA-induced paracrine molecular circuits in which the aberrant WNT4 signal production is a limiting step in shaping intratubular lesions and tumor expansion both in mouse model and human CNC testes.

pathology↗

bioRxiv2020

Computational Modelling of Cell Movements and Aggregations during Kidney Organogenesis

During early kidney organogenesis, nephron progenitor (NP) cells move from the tip to the corner region of the ureteric bud (UB) branches in order to form the pretubular aggregate, the early structure giving rise to nephron formation. Chemotaxis and cell-cell adhesion differences are believed to drive cell patterning during this critical period of organogenesis, but the spatiotemporal organization of this process is incompletely understood. We applied a Cellular Potts model to explore to how these processes contribute to directed cell movement and aggregation. Model parameters were estimated based on fitting to experimental data obtained in ex vivo kidney explant and dissociation-reaggregation organoid culture studies. Our simulations indicated that optimal enrichment and aggregation of NP cells in the UB corner niche requires chemoattractant secretion from both the UB epithelial cells and the NP cells themselves, as well as differences in cell-cell adhesion energies. Furthermore, NP cells were observed, both experimentally and by modelling, to move at higher speed in the UB corner as compared to the tip region where they originated. The existence of different cell speed domains along the UB was confirmed using self-organizing map analysis. In summary, we demonstrated the suitability of a Cellular Potts Model approach to simulate cell movement and patterning during early nephrogenesis. Further refinement of the model should allow us to recapitulate the effects of developmental changes of cell phenotypes and molecular crosstalk during organ development. Author SummaryThe emergence of tissue patterns during vertebrate development is a major interest of both experimental research and biocomputational modelling. In this study, we established a Cellular Potts Model to explore cellular processes during early kidney development. The goal was to elucidate movements and aggregations of nephron progenitor cells. These precursor cells derive from mesenchymal cells around the ureteric buds and eventually form the epithelial structure of the nephron. Moreover, we wanted to explore computationally the mechanisms how these cells segregate from metanephric mesenchyme and move towards the location where the nephron will be formed. Utilizing the Compucell3D simulation software, we developed a model which assumes that nephron progenitor movement and aggregation is governed by only two mechanisms, i.e. cell-cell adhesion differences between cell types and nephron progenitor cell chemotaxis in response to chemoattractant secretion from two sources. These sources were either the epithelial cells of a static ureteric bud and/or the nephron progenitor cells themselves. The simulations indicated faster average cell speeds near the ureteric bud corner, the target region of cell movement and aggregation, and slower speeds near the place of origin, the tip of ureteric bud. The results were validated by comparison of the model predictions with experimental data from two ex vivo embryonic kidney models and a computational optimization protocol.

systems biology↗