Biology subjects

Marciano, D.

Publications and source records attributed to Marciano, D..

13 recordsLinked to original sources

bioRxiv2025

Accelerated plastic aging in suspension (APAS): A simple, reproducible approach for the generation of model micro- and nanoplastics through simulated environmental forces

The environmental fragmentation of plastic waste leads to the formation of micro- and nanoplastics (MNPs), which pose serious ecological and human health concerns. Despite increasing interest in their biological effects, many studies rely on artificial, uniform particles that fail to mimic the diverse physical and chemical characteristics of real-world MNPs. To address this limitation, we developed the Accelerated Plastic Aging in Suspension (APAS) system--a scalable, reproducible method that mimics natural aging processes by combining ultraviolet (UV) radiation, thermal stress, and mechanical shear to generate environmentally relevant MNPs from commonly used polymers. We used APAS to fragment polyethylene terephthalate (PET), polyamide 6 (Nylon), and polyacrylonitrile (PAN), and observed time-dependent degradation, including the spontaneous formation of nanoplastics (<100 nm). Flow cytometry revealed substantial increases in particle number and reductions in average particle size over 12 weeks. Imaging flow cytometry confirmed consistent generation of heterogeneous, irregular particles across replicate batches. High-resolution imaging via AFM, TEM, and SEM confirmed the presence of nanoplastics with textured and irregular morphologies. Chemical characterization showed APAS aging altered particle surface charge and induced polymer-specific changes in autofluorescence and Raman spectral profiles, consistent with oxidative surface modifications. Laser Direct Infrared (LDIR) imaging further confirmed structural and chemical changes in polymer spectra post-aging. Functionally, under physiologically relevant shear flow conditions, endothelial cells internalized APAS-generated PET MNPs at significantly higher levels than polystyrene (PS) beads of similar size. Uptake was enhanced particularly under oscillatory flow, highlighting the influence of particle physicochemical properties on cellular interactions. Together, these findings demonstrate the ability of the APAS system to produce complex and realistic MNPs for use in environmental and toxicological studies. The system enables generation of nanoplastics and supports more accurate modelling of biological exposure scenarios compared to conventional synthetic particles.

pharmacology and toxicology↗

bioRxiv2025

Multiple Wnt signaling pathways direct epithelial tubule interconnection in the regenerating zebrafish kidney

Epithelial tubule fusion is fundamental for kidney morphogenesis. Differentiating nephron tubules interconnect with collecting system epithelia to generate a lumenal pathway for fluid excretion. In the adult zebrafish kidney, nephrogenesis occurs as a regenerative response to injury and provides a model to explore cell signaling pathways required for tubule interconnection. We show that canonical Wnt signaling at the junction between two tubules induces a mesenchymal, invasive cell phenotype and is required, along with Src kinase and rac1, to generate basal cell protrusions. The Wnt ligands wnt9b and wnt4 are both required for new nephron formation after injury. Mutation in wnt4 or treatment with the canonical Wnt inhibitor IWR1 blocks formation of basal protrusions in forming nephrons. Mutation in the Wnt receptor frizzled9b reveals a fusion-associated non-canonical Wnt pathway that acts to 1) restrict canonical Wnt gene expression, 2) drive Rho kinase-dependent apical constriction of epithelial cells, and 3) position basal protrusions and generate orthogonal tubule lumenal connections. As a result, frizzled9b mutant nephrons fail to fully interconnect with target distal tubules. Our results indicate that canonical and non-canonical Wnt signaling interact in the same cells to orient and drive tubule interconnection in the regenerating zebrafish kidney.

developmental biology↗

bioRxiv2024

The mechanical anisotropy of adipose tissues regulates ovarian cancer invasion

High-grade serous ovarian cancer, the most common and aggressive form of ovarian cancer, generally metastasises to visceral adipose tissues. In these tissues, the extracellular matrix through which ovarian cancer cells adhere and migrate is confined by the presence and preponderance of adipocytes. How cells migrate in this unique environment is not known, yet critical to understanding metastatic progression. To study these processes, we develop biomimetic organo-hydrogels that recreate structural and mechanical properties of human visceral adipose tissues. We show that ovarian cancer cells present invasive tropism towards organo-hydrogels, replicating the behaviour observed in native adipose tissues. This migration is facilitated by the mechanical anisotropy and microstructure of organo-hydrogels and adipose tissues, allowing the formation of cell force-induced migratory tracks, a process regulated by TGF{beta} in an MMP degradation-independent manner. These results highlight the contribution of adipocytes to tissue biophysical features as a key regulatory factor of ovarian cancer cell migration.

bioengineering↗

bioRxiv2024

Epithelial tubule interconnection driven by HGF-Met signaling in the kidney

The formation of functional epithelial tubules is a central feature of many organ systems. Although the process of tubule formation by epithelial cells is well-studied, the way in which tubules connect with each other (i.e. anastomose) to form functional networks both in vivo and in vitro is not well understood. A key, unanswered question in the kidney is how the renal vesicles of the embryonic kidney connect with the nascent collecting ducts to form a continuous urinary system. We performed a ligand-receptor pair analysis on single cell RNA-seq data from embryonic mouse kidney tubules undergoing anastomosis to select candidates that might mediate this process in vivo. This analysis identified hepatocyte growth factor (HGF), which has known roles in cell proliferation, migration, and tubulogenesis, as one of several possible candidates. To test this possibility, we designed a novel assay to quantitatively examine epithelial tubule anastomosis in vitro using epithelial spheroids with fluorescently-tagged apical surfaces to enable direct visualization of anastomosis. This revealed that HGF is a potent inducer of tubule anastomosis. Tubule anastomosis occurs through a proliferation-independent mechanism that acts through the MAPK signaling cascade and matrix metalloproteinases (MMPs), the latter suggestive of a role in extracellular matrix turnover. Accordingly, treatment of explanted embryonic mouse kidneys with HGF and collagenase was sufficient to induce kidney tubule anastomosis. These results lay the groundwork for investigating how to promote functional interconnections between tubular epithelia, which have important clinical implications for utilizing in vitro grown kidney tissue in transplant medicine.

developmental biology↗

bioRxiv2023

Engineered Protein Nanosheets for the Scale up of Mesenchymal Stem Cell Culture on Bioemulsions

The rapid progress in cell therapies and stem cell technologies requires the development of novel bioprocessing and biomanufacturing pipelines able to cope with the scale up of cell manufacturing. In this respect, microdroplet technologies have already revolutionised the field of biotechnologies, but remain ill-suited to the culture of adherent cells. In this report, we describe the engineering of albumins with cell adhesive peptides for the stabilisation of microdroplets enabling the scale up of mesenchymal stem cell (MSC) expansion. We characterise the modified albumins prior to study their self-assembly at liquid-liquid interfaces via interfacial shear rheology, and mechanical strengthening through the formation of crosslinked nanosheets. The biofunctionalisation of these protein nanosheets is then characterised by fluorescence microscopy. In turn, the ability of the resulting bioactive microdroplets to promote rapid cell adhesion and expansion is examined and the extensive deposition of matrix associated with such cultures is characterised. The culture of MSCs is then scaled up 100 fold, first at the surface of fluorinated oil emulsions, then on plant-based emulsions stabilised by engineered protein nanosheets and the phenotype of resulting cells is characterised. The microdroplet culture system presented displays attractive advantages over existing technologies, in terms of simplicity of processing, compatibility with regulatory expectations and costs of production, and offers exciting opportunities for translation to cell manufacturing, for cell therapies and cultivated meat applications.

bioengineering↗

bioRxiv2023

Biomimetic Artificial Bone Marrow Niches for the Scale Up of Hematopoietic Stem Cells

Hematopoietic stem cell (HSC) transplantation to treat haematological disorders is greatly restricted by poor cell availability. Ex vivo expansion of HSCs as a strategy to overcome this limitation has shown limited success so far, due to the loss of stem cell properties in culture. Therefore, engineering of culture platforms that mimic the physiological properties of the bone marrow (BM) in a scalable format is an important target to enable the translation of HSC therapies. Here, we report the design of biomimetic BM niches that enable the culture of HSCs in a scalable 3D platform. Beyond cellular and biochemical components (e.g., matrix and growth factors), an important element of the BM microenvironment is its architecture, dense in adipocytes, with relatively limited matrix and anisotropic mechanical properties. To capture this context, we propose the use of bioemulsions1,2 in which oil microdroplets and associated mechanical anisotropy recreate important architectural features of the hematopoietic niche. Mesenchymal stem cells (MSCs) grown at the surface of such bioemulsion remodelled this environment, assembling an interstitial matrix mimicking that of the BM microenvironment composition. In addition, MSCs secreted important factors underpinning the crosstalk between stromal cells and HSCs in the native environment. HSCs cultured in the resulting artificial BM niches maintained stemness whilst expanding significantly (> 33-fold compared to HSCs cultured in suspension) and enabling scale up of expansion in conical flask bioreactors, to produce 2M cells in a single batch. This platform therefore harnesses engineered BM microenvironments and the processability of bioemulsions and microdroplet technologies to produce HSCs in a scalable format, for application in cell-based therapies.

bioengineering↗

bioRxiv2023

Dynamic expectations: Behavioral and electrophysiological evidence of sub-second updates in reward predictions

Expectations are often dynamic: any sports fan knows that expectations are rapidly updated as games unfold. Yet expectations have traditionally been studied as static. Here, using slot machines as a case study, we provide parallel behavioral and electrophysiological evidence of sub-second moment-to-moment changes in expectations. In Study 1, we show that the dynamics of the EEG signal before the slot machine stopped differed depending on the nature of the outcome, including not only whether the participant won or lost, but also how close they came to winning. In line with our predictions, Near Win Before outcomes (the slot machine stops one item before a match) were similar to Wins, but different than Near Win After (the machine stops one item after a match) and Full Miss (the machine stops two or three items from a match). In Study 2, we designed a novel behavioral paradigm to measure moment-to-moment changes in expectations via dynamic betting. We found that different outcomes also elicited unique expectation trajectories in the deceleration phase. Notably, these behavioral expectation trajectories paralleled Study 1s EEG activity in the last second prior to the machines stop. In Studies 3 (EEG) and 4 (behavior) we replicated these findings in the loss domain where a match entails a loss. Again, we found a significant correlation between behavioral and EEG results. These four studies provide the first evidence that dynamic sub-second updates in expectations can be behaviorally and electrophysiologically measured. Our findings open up new avenues for studying the ongoing dynamics of reward expectations and their role in healthy and unhealthy cognition.

neuroscience↗

bioRxiv2022

Rab11 is essential to pancreas morphogenesis, lumen formation and endocrine mass.

The molecular links between tissue-level morphogenesis and the differentiation of cell lineages in the pancreas remain elusive despite a decade of studies. We previously showed that in pancreas both these processes depend on proper lumenogenesis. The Rab GTPase Rab11 has been shown to be essential to epithelial lumen formation in vitro, however few studies have addressed its functions in vivo and none have tested its requirement in pancreas. Here, we show that Rab11 is critical to proper pancreas development. Co-deletion of the Rab11 isoforms Rab11A and Rab11B in the developing pancreatic epithelium (Rab11pancDKO) results in ~50% neonatal lethality, and surviving adult Rab11pancDKO mice exhibit defective endocrine function. Loss of Rab11 in the embryonic pancreas results in morphogenetic defects of the epithelium linked to defective lumen formation and interconnection. In contrast to wildtype cells, Rab11pancDKO cells attempt to form multiple lumens, resulting in a failure to coordinate a single apical membrane initiation site (AMIS) between groups of cells. We show that these defects are due to failures in vesicle trafficking, as apical components remain trapped within Rab11pancDKO cells. Together, these observations suggest Rab11 directly regulates epithelial lumen formation and morphogenesis. Our report links intracellular trafficking to organ morphogenesis in vivo, and presents a novel framework for decoding pancreatic development. HIGHLIGHTSO_LIRab11Af/f;Rab11B-/-;Pdx1-Cre pancreas displays disruption of epithelial organization and reduction of endocrine cell mass. C_LIO_LILoss of Rab11 results in disruption of pancreatic lumen continuity due to a failure of lumen formation. C_LIO_LIEpithelial cells lacking Rab11 display abnormal polarity. C_LI

developmental biology↗

bioRxiv2022

To share or not to share? iEEG evidence for state-dependent inequity encoding in the human OFC

Social decision-making requires the integration of reward valuation and social cognition systems, both dependent on the orbitofrontal cortex (OFC). How these two OFC functions interact is largely unknown. We recorded intracranial activity from the OFC of ten patients making choices in the context of different types of inequity (disadvantageous vs. advantageous). We found that high-frequency activity (70-150 HZ) encoded the amount of self-reward, consistent with previous reports. We also observed novel evidence for encoding in human OFC of the social counterparts reward as well as the type of inequity being experienced. Additionally, we find social context modulates reward encoding: depending on inequity type, reward encoding was switched on and off rapidly within electrodes, across trials. These results provide direct evidence for explicit encoding of self- and other- rewards in the human OFC, and for rapid and reversible changes in encoding schemes driven by socially relevant contexts.

neuroscience↗

bioRxiv2022

Encoding and decoding analysis of music perception using intracranial EEG

Music perception engages multiple brain regions, however the neural dynamics of this core human experience remains elusive. We applied predictive models to intracranial EEG data from 29 patients listening to a Pink Floyd song. We investigated the relationship between the song spectrogram and the elicited high-frequency activity (70-150Hz), a marker of local neural activity. Encoding models characterized the spectrotemporal receptive fields (STRFs) of each electrode and decoding models estimated the population-level song representation. Both methods confirmed a crucial role of the right superior temporal gyri (STG) in music perception. A component analysis on STRF coefficients highlighted overlapping neural populations tuned to specific musical elements (vocals, lead guitar, rhythm). An ablation analysis on decoding models revealed the presence of unique musical information concentrated in the right STG and more spatially distributed in the left hemisphere. Lastly, we provided the first song reconstruction decoded from human neural activity.

neuroscience↗

bioRxiv2020

ILC1-derived TGFβ1 drives intestinal remodelling

Organoids can shed light on the dynamic interplay between complex tissues and rare cell types within a controlled microenvironment. Here, we developed gut organoid co-cultures with type-1 innate lymphoid cells (ILC1) to dissect the impact of their accumulation in inflamed intestines. We demonstrate for the first time that murine and human ILC1 secrete TGF{beta}1, driving expansion of CD44v6+ epithelial crypts. ILC1 additionally express MMP9 and drive gene signatures indicative of extracellular matrix remodelling. We therefore encapsulated human epithelial-mesenchymal intestinal organoids in MMP-sensitive, synthetic hydrogels designed to form efficient networks at low polymer concentrations. Harnessing this defined system, we demonstrate that ILC1 drive matrix softening and stiffening, which we suggest occurs through balanced matrix degradation and deposition. Our platform enabled us to elucidate previously undescribed interactions between ILC1 and their microenvironment, which suggest that they may exacerbate fibrosis and tumour growth when enriched in inflamed patient tissues.

immunology↗

bioRxiv2019

Novel truncating mutations in CTNND1 cause a dominant craniofacial and cardiac syndrome

AbstractCTNND1 encodes the p120-catenin (p120) protein, which has a wide range of functions, including the maintenance of cell-cell junctions, regulation of the epithelial-mesenchymal transition and transcriptional signaling. Due to advances in next generation sequencing, CTNND1 has been implicated in human diseases including cleft palate and blepharocheilodontic syndrome (BCD) albeit only recently. In this study, we identify eight novel protein-truncating variants, six de novo, in thirteen participants presenting with craniofacial dysmorphisms including cleft palate and hypodontia, as well as congenital cardiac anomalies, limb dysmorphologies and neurodevelopmental disorders. Using conditional deletions in mice as well as CRISPR/Cas9 approaches to target CTNND1 in Xenopus, we identified a subset of phenotypes that can be linked to p120-catenin in epithelial integrity and turnover, and additional phenotypes that suggest mesenchymal roles of CTNND1. We propose that CTNND1 variants have a wider developmental role than previously described, and that variations in this gene underlie not only cleft palate and BCD but may be expanded to a broader velocardiofacial-like syndrome.

genetics↗

bioRxiv2019

Light-sheet microscopy with isotropic, sub-micron resolution and solvent-independent large-scale imaging

We present cleared tissue Axially Swept Light-Sheet Microscopy (ctASLM), which achieves sub-micron isotropic resolution, high optical sectioning capability, and large field of view imaging (870x870 m2) over a broad range of immersion media. ctASLM can image live, expanded, and both aqueous and organic chemically cleared tissue preparations and provides 2- to 5-fold better axial resolution than confocal or other reported cleared tissue light-sheet microscopes. We image millimeter-sized tissues with sub-micron 3D resolution, which enabled us to perform automated detection of cells and subcellular features such as dendritic spines.

bioengineering↗