Biology subjects

Franco, C.

Publications and source records attributed to Franco, C..

At least 19 recordsLinked to original sources

bioRxiv2026

Soft-Robotic Magnetic Microfluidic Catheter for Delivery of Aqueous-Based Dual-Component Embolic Formulations

Transcatheter embolization requires materials that can be steered through tortuous vessels, solidify rapidly in situ, remain clearly visible under fluoroscopy, and, ideally, carry therapeutic cargo without harming tissue. To meet these requirements, we present a fully water-based, two-component PEI-PEG hydrogel delivered through a soft-robotic, microfluidic catheter that keeps the precursors separate until they meet in a millimetre-scale mixing chamber at the tip. Fast amide cross-linking converts the liquid pair into a self-supporting gel within seconds, eliminating organic solvents and preventing catheter blockage. By adjusting precursor ratio and flow regime, the gel's stiffness and viscosity can be tuned over orders of magnitude, with the same chemistry allowing to occlude both high-flow arteries and fragile micro-vessels. The platform was validated in three escalating models. First, in ex-vivo perfused human placenta, the hydrogel filled targeted branches without reflux or fragmentation, demonstrating controlled delivery in clinically relevant vasculature. Next, in three porcine embolizations, splenic, hepatic and ascending pharyngeal arteries, the material achieved stable, selective occlusion with no migration, vasospasm or recanalization, showing seamless compatibility with standard interventional workflows. Finally, in rats bearing orthotopic liver tumours, drug-loaded hydrogel delivered through the hepatic artery concentrated doxorubicin inside tumours while sparing healthy tissue, confirming its potential for precision chemoembolization. These results position the PEI-PEG hydrogel and microfluidic catheter as a unified, image-guided platform that couples robust mechanical occlusion with site-specific drug delivery, offering a biocompatible alternative to current liquid embolics and expanding the therapeutic reach of minimally invasive embolization procedures.

bioengineering↗

bioRxiv2026

Post-transcriptional glucocorticoid receptor signalling synchronises circadian rhythms

Keeping cellular circadian clocks synchronised is critical for cellular and physiological health. Glucocorticoid (GC) hormones are the most potent systemic timing signal for cellular clocks, acting via the glucocorticoid receptor (GR), a transcription factor conventionally thought to synchronise cells by translocating into the nucleus and activating the transcription of clock genes. Our findings overturn this model: acute changes in GR translocation and nascent transcription are both dispensable for GC-resetting of the circadian clock. Instead, physiological GC pulses act post-transcriptionally to rapidly increase Period1 mRNA through enhanced RNA processing, not synthesis. This elevates PER1 protein production which, alone, is sufficient to reset the clock. Yet each pulse resets only a subset of cells, explaining why, in vivo, repeated daily hormonal cues are required for full re-entrainment after jet lag or shift work. We propose a new model for hormonal signalling to the circadian clock and identify RNA processing kinetics as a general regulatory lever for nuclear receptor signalling.

molecular biology↗

bioRxiv2026

Dynamic Nanoparticle Assembly-Based Biomedical Microrobots

Precise drug delivery within anatomically complex tissues demands systems capable of both active navigation and deep tissue access, properties that have remained difficult to reconcile in existing nanocarriers and microrobots. Here we introduce Dynabots, a dynamic microrobotic assembly constructed from multifunctional nanoparticles covalently linked by thermally cleavable molecular connectors. This nanoparticle-rich architecture enables the integration of magnetic, imaging, and therapeutic components while preserving a high content of functional material. Collective assembly imparts enhanced magnetic responsiveness and maneuverability, enabling controlled navigation through tortuous biological environments. Upon exposure to mild thermal stimuli, the assemblies undergo programmed disassembly, releasing individual nanoparticles that can diffuse through tissue for localized therapeutic action. We establish the programmable transitions, biocompatibility, and therapeutic efficacy of this process across in vitro and in vivo models, including real-time fluoroscopic guidance within anatomically realistic phantoms and live rodent and porcine systems. By integrating magnetic control, reconfigurable architecture, and stimulus-triggered disassembly, Dynabots unite navigational precision with tissue permeability, providing a versatile platform for adaptive and deep-tissue drug delivery.

bioengineering↗

bioRxiv2026

Dimerisation and twist reversal of the Lewy fold in α-synuclein mutants with Parkinson's disease and dementia

Dominantly inherited missense and gene dosage mutations in SNCA, the -synuclein gene, cause familial forms of Parkinsons disease and dementia. Here we report the structures of -synuclein filaments from the brains of such individuals. Pathogenic mutations A53T and G51D in SNCA give rise to singlets and doublets of the Lewy fold with a left-handed helical twist in the absence of a peptide-like density for island A. By contrast, filaments from the non-pathogenic variant H50Q consist of singlets of the right-handed Lewy fold with a density for island A, like filaments of wild-type -synuclein. The structures of filaments from homozygous mice transgenic for human mutant A53T -synuclein (line M83) are unlike those from human brains. They are more similar to the multiple system atrophy folds than to the Lewy fold of Parkinsons disease, Parkinsons disease dementia and dementia with Lewy bodies

biophysics↗

bioRxiv2026

YBX3 overexpression in mesothelioma drives aberrant cell proliferation

Malignant pleural mesothelioma (MpM) is a lethal tumour closely linked to asbestos exposure and is a cancer of unmet clinical need with no known oncogenic drivers. Recent advancements in technologies to identify RNA-binding proteins (RBPs) has uncovered an emerging role for RBP-RNA interactions in cancer progression and we therefore assessed changes in the RBPome of patient-derived MpM cell lines. We identify over 350 RBPs showing altered RNA binding, with functions consistent with key cancer hallmarks, and discovered YBX3 as a potential oncoprotein driving cell proliferation in MpM. Mechanistically we show the impact of YBX3 on cell growth is achieved through its control of the expression of the amino acid transporter SLC7A5/LAT1, with increased amino acid uptake increasing protein synthesis rates. Notably, we show the inhibition of cell growth by YBX3 deletion is recapitulated by the clinically-relevant SLC7A5/LAT1 inhibitor JPH203. Finally, we demonstrate that JPH203 sensitizes MpM cells to radiotherapy, which could provide a promising therapeutic strategy for MpM. TeaserHigher levels of YBX3 expression in mesothelioma increases cell proliferation and protein synthesis rates by upregulation of amino acid uptake.

molecular biology↗

bioRxiv2025

Sub-cellular chemical mapping in bacteria using correlated cryogenic electron and mass spectrometry imaging

Electron cryomicroscopy (cryo-EM) allows high-resolution spatial visualization of biological specimens, however, it is challenging to chemically identify densities observed in cryo-EM. To overcome this, we combined cryo-EM with chemical imaging using focused ion beam secondary ion mass spectrometry (FIB-SIMS) for integrated spatio-chemical analysis of untagged specimens. We show that our correlative workflow permits sub-cellular localisation of molecules inside bacterial cells and is compatible with cryogenic light microscopy and FIB-milled lamellae of multicellular specimens. To highlight biological insights enabled by the workflow, we studied the uptake of Bisphenol-AF, a widespread chemical pollutant, by environmental bacteria, revealing the storage of these chemicals within cytosolic phase-separated aggregates in pollutant-exposed cells, where they cannot be removed by the bacterial efflux machinery despite its robust upregulation. These mechanistic insights were directly facilitated by the versatile cryo-EM-FIB-SIMS technique, showing that it is an effective avenue to map elemental and molecular signatures in near-native biological samples, which can be extended in the future for multiple applications in cell biology and imaging.

molecular biology↗

bioRxiv2025

Structural basis of RECQL5-induced RNA polymerase II transcription braking and subsequent reactivation

During productive transcription elongation, the speed of RNA polymerase II (Pol II) is highly dynamic within individual genes and varies between different genes1,2. Unregulated rapid transcription elongation can lead to detrimental consequences such as transcription-replication collisions, altered alternative splicing patterns, and genome instability1-7. Therefore, elongating Pol II requires mechanisms to slow its progression, yet the molecular basis of transcription braking remains unclear. RECQL5 is a DNA helicase that functions as a general elongation factor by slowing down Pol II8-11. Here we report cryo-electron microscopy (cryo-EM) structures of human RECQL5 bound to multiple transcription elongation complexes. Combined with biochemical analysis, we identify an -helix of RECQL5 responsible for Pol II binding and slowdown of transcription elongation. We further reveal that the transcription-coupled DNA repair (TCR) complex allows Pol II to overcome RECQL5-induced transcription braking through concerted actions of its translocase activity and competition with RECQL5 for engaging Pol II. Additionally, RECQL5 inhibits TCR-mediated Pol II ubiquitination to prevent activation of the DNA repair pathway. Our results suggest a model in which RECQL5 and the TCR complex coordinately regulate the transcription elongation rate to ensure transcription efficiency while maintaining genome stability. This work provides a framework for future studies on the regulatory role of elongation speed in gene expression.

molecular biology↗

bioRxiv2024

Design and Validation of a Wearable Imaging System for Automated Wound Monitoring in Porcine Model

Effective wound monitoring has the potential to guide treatment regiments and improve healing outcomes, yet current clinical assessment methods remain largely subjective and labor-intensive. To address this challenge, we present a high-resolution wearable imaging system designed for continuous wound monitoring. The system integrates a 64 MP camera with a plano-convex lens housed in an enclosure measuring 73 mm in diameter and 36.1 mm in height, and features a custom printed circuit board (PCB) for programmable LED illumination. The 3D-printed device enclosure is designed to accommodate a silicone bioelectronic device and can be securely attached using a commercially available ostomy skin barrier. In porcine model validation studies, the system successfully captured daily wound progression over periods up to 7 days. The captured images were wirelessly transmitted to a processing unit where DeepMapper, a machine learning algorithm, processed z-stacked images and performed multi-level feature extraction to predict wound healing stages and indicate potential complications such as infection. This imaging system enables automated analysis of wound progression and supports the development of smart wound care platforms for personalized treatment strategies. The integrated design approach demonstrates the feasibility of creating compact, high-resolution imaging systems suitable for clinical wound monitoring applications.

bioengineering↗

bioRxiv2024

Accelerating Wound Healing Through Deep Reinforcement Learning: A Data-Driven Approach to Optimal Treatment

Advancements in bioelectronic sensors and actuators have paved the way for real-time monitoring and control of wound healing progression. Real-time monitoring allows for precise adjustment in treatment strategies that align with an individuals unique biological response. However, due to the complexities of human-drug interactions and a lack of predictive models it is challenging to determine just how one should adjust drug dosage to achieve the desired biological response. This work proposes an adaptive closed-loop control framework that integrates deep learning, optimal control, and reinforcement learning to update treatment strategies in real-time with the goal of accelerating wound closure. The proposed approach eliminates the need for mathematical modeling of complex nonlinear wound healing dynamics. We demonstrate the convergence of the controller via an in silico experimental setup, where the proposed approach successfully accelerates the wound healing process by 17.71%. Finally, we share the experimental setup and results of an in vivo implementation to highlight the translational potential of our work. Our data-driven model estimates a 40% acceleration in wound closure.

systems biology↗

bioRxiv2024

Remote-Controlled Wireless Bioelectronics for Fluoxetine Therapy to Promote Wound Healing in a Porcine Model

Wound healing presents a significant challenge in biomedical science, requiring precise therapeutic delivery and real-time monitoring. Bioelectronic systems offer a promising solution but remain largely unexplored for wound care, particularly in large animal models that reflect human healing dynamics. This study introduces a remote controlled wireless bioelectronic platform equipped with an iontophoretic pump to deliver fluoxetine, a selective serotonin reuptake inhibitor that promotes wound repair. In vitro and ex-vivo testing validated efficient on demand fluoxetine delivery. In vivo experiments in a porcine wound model demonstrated clear therapeutic efficacy over 3-day and 7-day periods. The system enhanced healing outcomes, increasing re-epithelialization by 37% (H&E staining), reducing the M1/M2 macrophage ratio by 33%, and stimulating neuronal growth at the wound site. This bioelectronic platform delivers fluoxetine in a controlled, remotely-controlled manner while allowing for wound direct wound imaging that can be used to monitor wound healing progress. Additionally, it allows precise dose and temporal delivery of treatment to enhance the outcome of future large animal wound healing studies.

bioengineering↗

bioRxiv2024

Wireless bioelectronic device for wound healing

Wireless bioelectronic actuators have been developed to deliver targeted treatments over multiple days while continuously monitoring delivery, thereby improving wound healing. Specifically, these devices can deliver charged biomolecules such as fluoxetine cations (Flx+) and electric field (EF) in freely moving pigs. Treatments can be controlled and monitored in real time via WiFi, with options for both user-specified delivery rates and durations, as well as automated closed-loop (CL) control. The devices are engineered to handle various failure scenarios that may arise in dynamic, real-world experiments--such as communication or power interruptions--ensuring that valuable experimental data is collected with minimal disruption. The ion pump features eight drug reservoirs and channels arranged around a 20 mm diameter-wound, with a central ground electrode (0 V). When voltages above 0 V are applied to the outer channels, currents flow from the reservoirs and channels into the wound, delivering Flx+ and/or EF depending on the reservoir solution. The device records applied voltages and currents locally to a microSD card at a high sampling rate, while simultaneously transmitting real-time measurements via a local WiFi network to a wound healing algorithm running on a nearby laptop. CL control of current/delivery rate is performed by an onboard microcontroller unit (MCU) and current-source microchips, based on instructions received from the wound healing algorithm. A graphical user interface (GUI) provides intuitive user control and real-time data visualization, with support for multiple devices. In vivo studies over seven days showed that Flx+-treated wounds had a 20% lower M1/M2 macrophage ratio and 41.67% greater re-epithelialization compared to controls (standard-of-care), demonstrating the actuators potential to enhance wound healing.

biochemistry↗

bioRxiv2024

Identification of Cellular Signatures Associated with Chinese Hamster Ovary (CHO) Cell Adaptation for Secretion of Antibodies

The secretory capacity of Chinese hamster ovary (CHO) cells remains a fundamental bottleneck in the manufacturing of protein-based therapeutics. Unconventional biological drugs with complex structures and processing requirements are particularly problematic. Although engineered vector DNA elements can achieve rapid and high-level therapeutic protein production, a high metabolic and protein folding burden is imposed on the host cell. Cellular adaptations to these conditions include differential gene expression profiles that can in turn influence the productivity and quality control of recombinant proteins. In this study, we used quantitative transcriptomics and proteomics analyses to investigate how biological pathways change with antibody titre. Gene and protein expression profiles of CHO pools and clones producing a panel of different monoclonal and bispecific antibodies were analysed during fed-batch production. Antibody-expressing CHO pools were heterogeneous, resulting in few discernible genetic signatures. Clonal lines derived from these pools, selected for high and low production, yielded a small number of differentially expressed proteins that correlated with productivity and were shared across biotherapeutics. However, the dominant feature associated with higher protein production was transgene copy number and resulting mRNA expression level. Moreover, variability between clones suggested that the process of cellular adaptation is variable with diverse cellular changes associated with individual adaptation events.

bioengineering↗

bioRxiv2024

Tau filaments with the Alzheimer fold in cases with MAPT mutations V337M and R406W

Frontotemporal dementia (FTD) and Alzheimers disease are the most common forms of early-onset dementia. Dominantly inherited mutations in MAPT, the microtubule-associated protein tau gene, cause FTD and parkinsonism linked to chromosome 17 (FTDP-17). Individuals with FTDP-17 develop abundant filamentous tau inclusions in brain cells. Here we used electron cryo-microscopy to determine the structures of tau filaments from the brains of individuals with MAPT mutations V337M and R406W. Both mutations gave rise to tau filaments with the Alzheimer fold, which consisted of paired helical filaments in all V337M and R406W cases and of straight filaments in two V337M cases. We also identified a new assembly of the Alzheimer fold into triple tau filaments in a V337M case. Filaments assembled from recombinant tau(297-391) with mutation V337M had the Alzheimer fold and showed an increased rate of assembly.

biophysics↗

bioRxiv2023

Nicotine in adolescence freezes dopamine circuits in an immature state

Nicotine use during adolescence is largely associated with negative long-term outcomes, including addiction to nicotine in adulthood. How nicotine acts on developing neurocircuitry in adolescence remains largely unknown, but may hold the key for informing more effective intervention efforts. We found transient nicotine exposure in early adolescence was sufficient for adult mice to show a marked vulnerability to nicotine. Brain-wide activity mapping showed that these mice had an enhanced response to an acute nicotine injection and widespread disruption of functional connectivity in comparison to controls, particularly within dopaminergic networks. Neurophysiological analysis further revealed that their ventral tegmental area (VTA) dopamine neurons show an immature basal plasticity signature and an adolescent-like imbalance in nicotine-induced activity between nucleus accumbens (NAc) and amygdala (AMG)-projecting pathways, known to respectively produce the reinforcing and anxiogenic effects of nicotine. The anxiogenic effect of nicotine is abolished in adult mice treated with nicotine in adolescence, strongly resembling the normal phenotype of young mice. Together these results suggest that nicotine exposure in adolescence somehow "froze" both their neural circuit and behavioral reaction to nicotine, carrying an adolescent-like vulnerability to the drug into adulthood. Finally, we are able to "thaw" the behavioral response to acute nicotine in adolescent-exposed mice by chemogenetically resetting the balance between the underlying NAc- and AMG-projecting dopamine circuits, restoring a mature anxiety-like response to acute nicotine. Together, our results highlight how diverse dopamine pathways can be impacted by experience in adolescence, and further suggest that the perseverance of a developmental imbalance between dopamine pathways may alter vulnerability profiles for later dopamine-dependent psychopathologies.

neuroscience↗

bioRxiv2023

Cryo-EM structures of Aβ40 filaments from the leptomeninges of individuals with Alzheimer's disease and cerebral amyloid angiopathy

We used electron cryo-microscopy (cryo-EM) to determine the structures of A{beta}40 filaments from the leptomeninges of individuals with Alzheimers disease and cerebral amyloid angiopathy. In agreement with previously reported structures, which were solved to a resolution of 4.4 [A], we found three types of filaments. However, our new structures, solved to a resolution of 2.4 [A] resolution, revealed differences in the sequence assignment that redefine the fold of A{beta}40 peptides and their interactions. Filaments are made of pairs of protofilaments, the ordered core of which comprises D1-G38. The different filament types comprise one, two or three protofilament pairs. In each pair, residues H14-G37 of both protofilaments adopt an extended conformation and pack against each other in an anti-parallel fashion, held together by hydrophobic interactions and hydrogen bonds between main chains and side chains. Residues D1-H13 fold back on the adjacent parts of their own chains through both polar and non-polar interactions. There are also several additional densities of unknown identity. Sarkosyl extraction and aqueous extraction gave the same structures. By cryo-EM, parenchymal deposits of A{beta}42 and blood vessel deposits of A{beta}40 have distinct structures, supporting the view that Alzheimers disease and cerebral amyloid angiopathy are different A{beta} proteinopathies.

neuroscience↗

bioRxiv2023

Astrocyte aquaporin mediates a tonic water efflux maintaining brain homeostasis

Brain water homeostasis not only provides a physical protection, but also determines the diffusion of chemical molecules key for information processing and metabolic stability. As a major type of glia in brain parenchyma, astrocytes are the dominant cell type expressing aquaporin water channel. How astrocyte aquaporin contributes to brain water homeostasis in basal physiology remains to be understood. We report that astrocyte aquaporin 4 (AQP4) mediates a tonic water efflux in basal conditions. Acute inhibition of astrocyte AQP4 leads to intracellular water accumulation as optically resolved by fluorescence-translated imaging in acute brain slices, and in vivo by fiber photometry in mobile mice. We then show that aquaporin-mediated constant water efflux maintains astrocyte volume and osmotic equilibrium, astrocyte and neuron Ca2+ signaling, and extracellular space remodeling during optogenetically induced cortical spreading depression. Using diffusion-weighted magnetic resonance imaging (DW-MRI), we observed that in vivo inhibition of AQP4 water efflux heterogeneously disturbs brain water homeostasis in a region-dependent manner. Our data suggest that astrocyte aquaporin, though bidirectional in nature, mediates a tonic water outflow to sustain cellular and environmental equilibrium in brain parenchyma. Significance statementOur brain is immersed, thus protected, in a water environment. It ensures intra- and extracellular molecular diffusion, which is vital for brain function and health. Brain water homeostasis is maintained by dynamic water transport between different cell types. Astrocytes are a main type of glial cell widely distributed in brain parenchyma, expressing the bidirectional aquaporin water channel. Here we show that in basal conditions, aquaporin channel mediates a tonic water efflux from astrocytes. This mechanism maintains astrocyte volume stability, activity-gated brain parenchyma remodeling and brain water homeostasis. Our finding sheds light on how astrocytes regulate water states in the brain, and will help to understand brain allostasis in specific life contexts.

physiology↗

bioRxiv2023

A non-genetic model of vascular shunts informs on the cellular mechanisms of formation and resolution of arteriovenous malformations

Arteriovenous malformations (AVMs), a disorder characterized by direct shunts between arteries and veins, are associated with genetic mutations. However, the mechanisms leading to the transformation of a capillary into a shunt remain unclear and how shunts can be reverted into capillaries is poorly understood. Here, we report that oxygen-induced retinopathy (OIR) protocol leads to the consistent and stereotypical formation of AV shunts in non-genetically altered mice. OIR-induced AV shunts show all the canonical markers of AVMs. Genetic and pharmacological interventions demonstrated that changes in endothelial cell (EC) volume of venous origin (hypertrophic venous cells) are the initiating step promoting AV shunt formation, whilst EC proliferation or migration played minor roles. Inhibition of mTOR pathway prevents pathological increases in EC volume and significantly reduces the formation of AV shunts. Importantly, we demonstrate that ALK1 signaling cell-autonomously regulates EC volume, demonstrating that our discoveries link with hereditary hemorrhagic telangiectasia (HHT)-related AVMs. Finally, we demonstrate that a combination of EC volume control and EC migration is associated with the regression of AV shunts. We demonstrate that an increase in the EC volume is the key mechanism driving the initial stages of AV shunt formation, leading to asymmetric capillary diameters. Based on our results, we propose a coherent and unifying timeline leading to the fast conversion of a capillary vessel into an AV shunt. Our data advocates for further investigation into the mechanisms regulating EC volume in health and disease as a way to identify therapeutic approaches to prevent and revert AVMs.

cell biology↗

bioRxiv2023

Astrocytes control cocaine-induced synaptic plasticity and reward through the matricellular protein hevin

Drug addiction involves profound modifications of neuronal plasticity in the nucleus accumbens, which may engage various cell types. Here, we report prominent effects of cocaine on calcium signals in astrocytes characterized by in vivo fiber photometry. Astrocyte calcium signals in the nucleus accumbens are sufficient and necessary for the acquisition of cocaine seeking behavior. We identify the astrocyte-secreted matricellular protein hevin as an effector of the action of cocaine and calcium signals on reward and neuronal plasticity.

neuroscience↗