Biology subjects

Franze, K.

Publications and source records attributed to Franze, K..

At least 19 recordsLinked to original sources

bioRxiv2025

Fibrin-containing Hydrogels Regulate Human Astrocyte State and Neuronal Reprogramming

Astrocytes are key components in reactive gliosis after brain injury, yet defined in vitro models dissecting the influence of extracellular matrix (ECM) components enriched after injury, such as fibrin, on human astrocyte behaviour and function are still missing. Here, we use fibrinogen-derived fibrin and fibrin-alginate-RGD (FAR) 3D hydrogel substrates to examine the influence on human iPSC-derived astrocyte behaviour and their direct conversion into neurons. Astrocytes develop complex morphologies in 3D-FAR hydrogels while are more proliferative and migratory in 3D-Fibrin. Interestingly, gene expression profile analysis revealed different reactive states of astrocytes in 3D-Fibrin and 3D-FAR, which persist over time. The highly inflammatory state in 3D-FAR is largely incompatible with direct neuronal reprogramming hampering the direct conversion even at early stages. Conversely, astrocytes in 3D-Fibrin hydrogels can readily convert into neurons, demonstrating a potent influence of how fibrin is presented on eliciting distinct astrocyte states with great relevance for fate conversion. Research highlightsO_LIFirst transcriptome of human astrocytes in 3D-Fibrin hydrogel and derivative C_LIO_LIFibrin-alginate-RGD (3D-FAR) hydrogel elicits high branching complexity along with exacerbated reactive signature in astrocytes C_LIO_LI3D-Fibrin hydrogels enable proliferation and migration of astrocytes C_LIO_LIDirect conversion of human iPSC-derived astrocytes into neurons in 3D-Fibrin hydrogel C_LI

neuroscience↗

bioRxiv2025

Actin conformation dynamics precede force generation in cytotoxic T lymphocytes

Cytotoxic T lymphocytes (CTLs) are cells of the adaptive immune system that are able to recognise and kill cancerous or virally infected target cells. The biochemical basis of CTL-mediated killing has been examined in great detail. Recent work has underscored the importance of physical forces in T cell function too, but how CTLs sense and exert force during migration and killing is not fully understood. Here, by expressing actin conformation probes based on the CH domain of utrophin, we directly visualize regions of altered F-actin conformation in primary CTLs during migration and killing. By combining these probes with traction force microscopy, we correlate external force with the internal cytoskeleton. We show that actin conformation is regulated upstream of force production, and that force exertion at the cytotoxic immune synapse temporally follows actin conformation dynamics. Our work offers novel insight into the relationship between cellular force production and F-actin conformation in important primary immune cells.

cell biology↗

bioRxiv2025

Glycan Atlassing: Nanoscale analysis of glycocalyx architecture enables functional tracing of cell state

The glycocalyx is a complex layer of glycosylated biomolecules surrounding all cells in the human body. It is involved in the regulation of critical cellular processes such as immune response modulation, cell adhesion, and host-pathogen interactions. Despite these insights, the functional relationship between glycocalyx architecture and cellular state has remained elusive so far, mainly attributable to the structural diversity of glycocalyx constituents and their nanoscale organization. Here, we show that DNA-tagged lectin labeling and metabolic oligosaccharide engineering enables multiplexed super-resolution microscopy of glycocalyx constituents, yielding an atlas of glycocalyx architecture with nanometer resolution. Quantitative analysis of the obtained nanoscale map of glycocalyx constituents facilitates the extraction of characteristic spatial relationships that accurately report on cellular state. We demonstrate the capacity of our approach, which we term Glycan Atlassing, across cell and tissue types, ranging from cultured cell lines to primary immune cells, neurons, and primary patient tissue. Glycan Atlassing establishes a powerful strategy for investigating glycocalyx remodeling in development and disease, potentially enabling the development of new glycocalyx-centered targets in diagnosis and therapy.

biophysics↗

bioRxiv2025

Measurement force, speed and post-mortem time affect the ratio of CNS grey to white matter elasticity

For several decades, many attempts have been made to characterise the mechanical properties of grey and white matter, which constitute the two main compartments of the central nervous system (CNS), with various methods and contradictory results. In particular, the ratio of grey-to-white-matter elasticity is sometimes larger than 1 and sometimes smaller; the reason for this apparent discrepancy is currently unknown. Here, we exploited atomic force microscopy (AFM)-based indentation measurements to systematically investigate how the measurement force, measurement speed, post-mortem interval and temperature affect the measured elasticity of spinal cord tissue, and in particular the ratio of grey-to-white-matter elasticity (Kg/Kw). Within the explored parameter space, increasing measurement force and speed increased the measured elasticity of both grey and white matter. However, Kg/Kw declined from values as high as [~]5 at low forces and speeds to [~]1 for high forces and speeds. Kg/Kw also strongly depended on the anatomical plane in which the measurements were conducted and was considerably higher in transverse sections compared to longitudinal sections. Furthermore, the post-mortem interval impacted both the absolute measured tissue elasticity and Kg/Kw. Grey matter elasticity started decreasing [~]3 hours post-mortem until reaching a plateau after [~]6 hours. In contrast, white matter elasticity started declining from the beginning of the measurements until [~]6 hours post-mortem, when it also levelled off. As a result, Kg/Kw increased until [~]6 hours post-mortem before stabilising. Between 20{degrees}C and 38{degrees}C, both grey and white matter elasticity decreased at a similar rate, without affecting Kg/Kw. We have thus identified differences in the response of grey and white matter to varying strains and strain rates, and the post-mortem interval, and excluded temperature as a factor affecting Kg/Kw. These differential responses likely contribute to the contradictory results obtained with different methods working in different strain regimes. Statement of significanceWe here showed that the mechanical response of CNS grey and white matter to an applied force differentially depends on measurement parameters such as the speed and magnitude of the applied forces, the post-mortem interval, as well as the anatomical axis along which measurements are conducted. These results broaden our understanding of CNS mechanics and pave the way for better and more targeted experimental design of future experiments. Ultimately, they may help to reconcile seemingly contradictory results in the literature concerning the ratio of grey-to-white-matter elasticity.

biophysics↗

bioRxiv2025

Biphasic inflammation control by dedifferentiated fibroblasts enables axon regeneration after spinal cord injury in zebrafish

Fibrosis and persistent inflammation are interconnected processes that inhibit axon regeneration in the mammalian central nervous system (CNS). In zebrafish, by contrast, fibroblast-derived extracellular matrix deposition and inflammation facilitate regeneration. However, the regulatory cross-talk between fibroblasts and the innate immune system in the regenerating CNS is not understood. Here, we show that zebrafish fibroblasts possess a dual role in inducing and subsequently resolving inflammation, which are both essential for regeneration. We identify a transient, injury-specific cthrc1a+ fibroblast state with an inflammation-associated, less differentiated, and non-fibrotic profile. Induction of this fibroblast state precedes and contributes to the initiation of the inflammatory response. At the peak of neutrophil influx, cthrc1a+ fibroblasts coordinate the resolution of inflammation. Disruption of these inflammation dynamics inhibits axon regeneration and alters the mechano-structural properties of the lesion environment. This establishes the biphasic inflammation control by dedifferentiated fibroblasts as a pivotal mechanism for CNS regeneration. ONE SENTENCE SUMMARYDedifferentiated fibroblasts sequentially induce and resolve neutrophil-driven inflammation through cytokine release to facilitate axon regeneration after spinal cord injury in zebrafish. HIGHLIGHTSO_LITime-resolved single-cell transcriptomics of zebrafish spinal cord regeneration. C_LIO_LISpinal cord injury induces fibroblast dedifferentiation. C_LIO_LIDedifferentiated fibroblasts sequentially induce and resolve inflammation. C_LIO_LIDysregulation of inflammation dynamics alters mechano-structural tissue properties. C_LI

neuroscience↗

bioRxiv2024

Hyaluronic Acid and Emergent Tissue Mechanics Orchestrate Digit Tip Regeneration

Tissue regeneration is a dynamic process requiring coordinated cell fate decisions to restore structure and function. For instance, the tips of human and rodent digits fully regrow after amputation, although more proximal injuries fail to regenerate. While biochemical cues have been widely studied in wound healing, the role of the physical microenvironment remains less understood. Here, we discovered that tissue mechanics and extracellular matrix (ECM) composition differ markedly between non-regenerating and regenerating wounds. These differences are due to specific fibroblast sub-types which predominate in the non-regenerating wound and form fibrotic collagen networks. Conversely, bone-forming progenitors in regenerating digits synthesize abundant hyaluronic acid, which mediates collagen fibrillogenesis. By modeling the tissue mechanics of non-regenerative and regenerative wounds using hydrogels, we showed that substrate stiffness regulates the synthesis of fibrotic and regenerative ECM. We further revealed that mimicking the regenerative wound mechanics upregulated bone morphogenic protein signaling and osteogenic differentiation. We ultimately demonstrated that the link protein HAPLN1 promotes hyaluronic acid deposition in vivo, reduces scar formation, and induces bone repair after non-regenerative amputations. These findings emphasize the interplay among the ECM, tissue mechanics, and cell behavior in digit regeneration and point towards ECM modulation as a strategy to improve wound healing. HighlightsO_LINon-regenerating and regenerating digit tips diverge in their cellular and ECM composition C_LIO_LIRegeneration requires hyaluronic acid matrix, which mediates collagen assembly and tissue mechanics C_LIO_LISoft substrates enhance BMP signaling and propagate the synthesis of regenerative ECM C_LIO_LIHAPLN1 overexpression initiates rescue of non-regenerative digit tip amputations C_LI

developmental biology↗

bioRxiv2024

Substrate stiffness regulates neuronal maturation via Piezo1-mediated TTR activity

During brain development, neurons extend axons to connect to their target cells while initiating a maturation process during which neurons start expressing voltage-gated ion channels, form synapses, express synaptic transmitters and receptors, and start communicating via action potentials. Little is known about external factors regulating this process. Here, we identified environmental mechanics as an important regulator of neuronal maturation, and a molecular pathway linking tissue stiffness to this process. Using patch clamp electrophysiology, calcium imaging and immunofluorescence, we found that neurons cultured on stiffer substrates showed a delay in voltage-gated ion channel activity, spontaneous and evoked action potentials, and synapse formation. RNA sequencing and CRISPR/Cas9 knockdown revealed that the mechanosensitive ion channel Piezo1 supresses transthyretin (TTR) expression on stiffer substrates, slowing down synapse formation and consequently electrical maturation. In agreement, the stiffness of developing Xenopus laevis brain negatively correlated with local synapse densities, and stiffening of brain tissue resulted in a significant delay of synaptic activity in vivo. Our data indicate that environmental stiffness represents a fundamental regulator of neuronal maturation, which is important for the development of normal circuitry in the brain, and potentially for neurodevelopmental disorders. Furthermore, the mechanical regulation of TTR downstream of Piezo1 may be found in many other biological systems.

developmental biology↗

bioRxiv2024

Long-range chemical signalling in vivo is regulated by mechanical signals

Biological processes are regulated by chemical and mechanical signals, yet the interaction between these signalling modalities remains poorly understood. Using the developing Xenopus laevis brain as a model system, we identified a critical crosstalk between tissue stiffness and long-range chemical signalling in vivo. Targeted knockdown of the mechanosensitive ion channel Piezo1 in retinal ganglion cells (RGCs) led to pathfinding errors in vivo. However, pathfinding errors were also observed in RGCs expressing Piezo1, when Piezo1 was downregulated in the surrounding brain tissue. Depleting Piezo1 in the brain parenchyma led to a decrease in the expression of the long-range chemical guidance cues Semaphorin3A (Sema3A) and Slit1, which instruct turning responses in distant cells. Furthermore, Piezo1 knockdown markedly reduced tissue stiffness. This tissue softening was independent of Sema3A depletion, and was caused by a decrease in the cell-cell adhesion proteins NCAM1 and N-Cadherin. Downregulating NCAM1 and N-Cadherin was sufficient to reduce tissue stiffness and Sema3A expression. Conversely, increasing environmental stiffness ex vivo resulted in enhanced tissue-level force generation and an increase in Slit1 and Sema3A expression. Moreover, stiffening soft brain regions in vivo induced ectopic Sema3A production via a Piezo1-dependent mechanism. Hence, tissue mechanics can locally modulate the availability of diffusive, long-range chemical signals, thus influencing cell function at sites distant from the mechanical cue. Such indirect regulatory mechanisms of cell function through mechanical signals are likely widespread across biological systems.

developmental biology↗

bioRxiv2024

Eph/ephrin signalling in the developing brain is regulated by tissue stiffness

Eph receptors and their membrane-bound ligands, ephrins, provide key signals in many biological processes, such as cell proliferation, cell motility and cell sorting at tissue boundaries. However, despite immense progress in our understanding of Eph/ephrin signalling, there are still discrepancies between in vitro and in vivo work, and the regulation of Eph/ephrin signalling remains incompletely understood. Since a major difference between in vivo and most in vitro experiments is the stiffness of the cellular environment, we here investigated the interplay between tissue mechanics and Eph/ephrin signalling using the Xenopus laevis optic pathway as a model system. Xenopus retinal neurons cultured on soft substrates mechanically resembling brain tissue showed the opposite response to ephrinB1 compared to those cultured on glass. In vivo atomic force microscopy (AFM)-based stiffness mapping revealed that the visual area of the Xenopus brain, the optic tectum, becomes mechanically heterogeneous during its innervation by axons of retinal neurons. The resulting stiffness gradient correlated with both a cell density gradient and expression patterns of EphB and ephrinB family members. Exposing ex vivo brains to stiffer matrices or locally stiffening the optic tectum in vivo led to an increase in EphB2 expression in the optic tectum, indicating that tissue mechanics is an important regulator of Eph/ephrin signalling. Similar mechanisms are likely to be involved in the development and diseases of many other organ systems.

developmental biology↗

bioRxiv2024

Differential tissue deformability underlies shape divergence of the embryonic brain and spinal cord under fluid pressure

An expanded brain enables the complex behaviours of vertebrates that promote their adaptation in diverse ecological niches1-3. Initial morphological differences between the brain and spinal cord emerge as the antero-posteriorly patterned neural plate folds to form the neural tube4-7 during embryonic development. Following neural tube closure, a dramatic expansion of the brain diverges its shape from the spinal cord8, setting their distinct morphologies for further development9,10. How the brain and the spinal cord expand differentially remains unclear. Here, using the chicken embryo as a model, we show that the hindbrain expands through dorsal tissue thinning under a positive hydrostatic pressure from the neural tube lumen11,12 while the dorsal spinal cord shape resists the same pressure. Using magnetic droplets and atomic force microscopy, we reveal that the dorsal tissue in the hindbrain is more fluid than in the spinal cord. The dorsal hindbrain harbours more migratory neural crest cells13 and exhibits reduced apical actin and a disorganised laminin matrix compared to the dorsal spinal cord. Blocking the activity of neural crest-associated matrix metalloproteinases inhibited dorsal tissue thinning, leading to abnormal brain morphology. Transplanting early dorsal hindbrain cells to the spinal cord was sufficient to create a region with expanded brain-like morphology including a thinned-out roof. Our findings open new questions in vertebrate head evolution and neural tube defects, and suggest a general role of mechanical pre-pattern in creating shape differences in epithelial tubes.

developmental biology↗

bioRxiv2022

Differential response of patient-derived primary glioblastoma cells to metabolic and adhesion inhibitors

PurposeThis study aims to investigate Glioblastoma (GBM) cellular response to adhesion and metabolic inhibitors in the context of cells migration and cell-matrix adhesion properties. GBM is the most common incurable brain tumour. Decades of work into GBM chemical and molecular classification have identified mechanisms of drug resistance. Inhibitors targeting cancer cell migration and proliferation rarely take into consideration the heterogeneous migration property amongst cells, which may impact patients response to treatment. MethodsTissue samples were obtained from spatially distinct locations with different 5-aminolevulinic acid (5-ALA) fluorescent intensities, strong strongly fluorescent tumour cores, a weak fluorescent tumour rim, and nonfluorescent tumour margins. Samples were previously shown to be associated with different motility and adhesion properties. We tested tumour cells response to adhesion and metabolic inhibitors using metabolic assays. Cell survival was also monitored using time-lapse microscopy, while cultured on low-modulus polydimethylsiloxane representative of the stiffness of brain tissue. ResultsMetabolic viability assays, MTT and Cell Titer, showed substantial heterogeneity in drug potency. Highly fluorescent tumour core cells were significantly more resistant to an F0F1 ATP synthase inhibitor (Gboxin), and a FAK inhibitor (GSK2256098), and cell proliferation ceased post-treatment in vitro. Cells derived from non-fluorescent tumour margins exhibited higher potency for the ATP synthase inhibitor (Gboxin). However, cell proliferation persisted post-treatment. ConclusionOur study suggests that the adhesive and migration properties of cells account for the sensitivity to therapeutics in different regions of the tumour in individual patients and between patients with GBM.

neuroscience↗

bioRxiv2022

Regenerative capacity of neural tissue scales with changes in tissue mechanics post injury

Spinal cord injuries have devastating consequences for humans, as mammalian neurons of the central nervous system (CNS) cannot regenerate. In the peripheral nervous system (PNS), however, neurons may regenerate to restore lost function following injury. While mammalian CNS tissue softens after injury, how PNS tissue mechanics changes in response to mechanical trauma is currently poorly understood. Here we characterised mechanical rat nerve tissue properties before and after in vivo crush and transection injuries using atomic force microscopy-based indentation measurements. Unlike CNS tissue, PNS tissue significantly stiffened after both types of tissue damage, likely mainly due to an increase in collagen I levels. Schwann cells, which crucially support PNS regeneration, became more motile and proliferative on stiffer substrates in vitro, suggesting that changes in tissue stiffness may play a key role in facilitating or impeding nervous system regeneration.

neuroscience↗

bioRxiv2022

EV Fingerprinting: Resolving extracellular vesicle heterogeneity using multi-parametric flow cytometry

Mammalian cells release a heterogeneous array of extracellular vesicles (EVs) that impact human biology by contributing to intercellular communication. To resolve EV heterogeneity and define the EV populations associated with specific biological processes, we developed a method named "EV Fingerprinting" that discerns distinct vesicle populations using dimensional reduction of multi-parametric data collected by quantitative single-EV flow cytometry. After validating this method against synthetic standards, the EV Fingerprinting analysis of highly purified EVs enabled a much more granular resolution of biochemically distinct EV populations than previously established methods. The analysis of EVs produced after molecular perturbation of EV biogenesis through ablation of the GTPase Rab27a and overexpression of the tetraspanin CD63 revealed that EV Fingerprinting reflects the molecular state of a cell. Subsequent analysis of human plasma demonstrates the capacity of EV Fingerprinting to resolve EV populations in complex biological samples and detect tumor-cell derived EVs.

cell biology↗

bioRxiv2022

Brain tissue mechanics is governed by microscale relations of the tissue constituents

Local mechanical tissue properties are a critical regulator of cell function in the central nervous system (CNS) during development and disorder. However, we still dont fully understand how the mechanical properties of individual tissue constituents, such as cell nuclei or myelin, determine tissue mechanics. Here we developed a model predicting local tissue mechanics, which induces non-affine deformations of the tissue components. Using the mouse hippocampus and cerebellum as model systems, we show that considering individual tissue components alone, as identified by immunohistochemistry, is not sufficient to reproduce the local mechanical properties of CNS tissue. Our results suggest that brain tissue shows a universal response to applied forces that depends not only on the amount and stiffness of the individual tissue constituents but also on the way how they assemble. Our model may unify current incongruences between the mechanics of soft biological tissues and the underlying constituents and facilitate the design of better biomedical materials and engineered tissues. To this end, we provide a freely-available platform to predict local tissue elasticity upon providing immunohistochemistry images and stiffness values for the constituents of the tissue.

biophysics↗

bioRxiv2022

Mutation of the ALS/FTD-associated RNA-binding protein FUS alters axonal cytoskeletal organisation

Aberrant condensation and localisation of the RNA-binding protein fused in sarcoma (FUS) occur in variants of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). ALS is also associated with cytoskeletal defects, genetically and through observations of compromised axonal transport. Here, we asked whether compromised axonal cytoskeletal organisation is an early feature of FUS-associated ALS/FTD. We used an ALS-associated mutant FUS(P525L) and the FTD-mimic hypomethylated FUS, FUS(16R), to investigate the common and distinct cytoskeletal changes found in these two reported Xenopus models. Combining a novel atomic force microscopy (AFM)-based approach for in vitro cytoskeletal characterisation and in vivo axonal branching analysis, we found that mutant FUS reduced actin density in the dynamically remodelling growth cone, and reduced axonal branch complexity. We furthermore found evidence of an axon looping defect for FUS(P525L). Therefore, we show that compromised actin remodelling is potentially an important early event in FUS-associated pathogenesis. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/510780v2_ufig1.gif" ALT="Figure 1"> View larger version (56K): org.highwire.dtl.DTLVardef@1e9a92aorg.highwire.dtl.DTLVardef@161076eorg.highwire.dtl.DTLVardef@12edf0forg.highwire.dtl.DTLVardef@365785_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2022

Plakoglobin is a mechanoresponsive regulator of naïve pluripotency

Biomechanical cues are instrumental in guiding embryonic development and cell differentiation. Understanding how these physical stimuli translate into transcriptional programs could provide insight into mechanisms underlying mammalian pre-implantation development. Here, we explore this by exerting microenvironmental control over mouse embryonic stem cells (ESCs). Microfluidic encapsulation of ESCs in agarose microgels stabilized the naive pluripotency network and specifically induced expression of Plakoglobin (Jup), a vertebrate homologue of {beta}-catenin. Indeed, overexpression of Plakoglobin was sufficient to fully re-establish the naive pluripotency gene regulatory network under metastable pluripotency conditions, as confirmed by single-cell transcriptome profiling. Finally, we found that in the epiblast, Plakoglobin was exclusively expressed at the blastocyst stage in human and mouse embryos - further strengthening the link between Plakoglobin and naive pluripotency in vivo. Our work reveals Plakoglobin as a mechanosensitive regulator of naive pluripotency and provides a paradigm to interrogate the effects of volumetric confinement on cell-fate transitions. HighlightsO_LI3D agarose spheres stabilize the naive pluripotency network in mouse ESCs. C_LIO_LIVolumetric confinement induces expression of Plakoglobin, a vertebrate homologue of {beta}-catenin. C_LIO_LIPlakoglobin expression in the epiblast is specific to pre-implantation human and mouse embryos. C_LIO_LIPlakoglobin overexpression maintains naive pluripotency independently of {beta}-catenin. C_LI

developmental biology↗

bioRxiv2021

Effective Cell Membrane Tension is Independent of Substrate Stiffness

Most animal cells are surrounded by a cell membrane and an underlying actomyosin cortex. Both structures are linked, and they are under tension. In-plane membrane tension and cortical tension both influence many cellular processes, including cell migration, division, and endocytosis. However, while actomyosin tension is regulated by substrate stiffness, how membrane tension responds to mechanical substrate properties is currently poorly understood. Here, we probed the effective membrane tension of neurons and fibroblasts cultured on glass and polyacrylamide substrates of varying stiffness using optical tweezers. In contrast to actomyosin-based traction forces, both peak forces and steady state tether forces of cells cultured on hydrogels were independent of substrate stiffness and did not change after blocking myosin II activity using blebbistatin, indicating that tether and traction forces are not directly linked. Peak forces in fibroblasts on hydrogels were about twice as high as those in neurons, indicating stronger membrane-cortex adhesion in fibroblasts. Steady state tether forces were generally higher in cells cultured on hydrogels than on glass, which we explain by a mechanical model. Our results provide new insights into the complex regulation of effective membrane tension and pave the way for a deeper understanding of the biological processes it instructs.

biophysics↗

bioRxiv2021

Unrestrained growth of correctly oriented microtubules instructs axonal microtubule orientation

In many eukaryotic cells, directed molecular transport occurs along microtubules. Within neuronal axons, transport over vast distances particularly relies on uniformly oriented microtubules, whose +-ends point towards the distal axon tip (+end out). However, axonal microtubules initially have mixed orientations, and how they orient during development is not yet fully understood. Using live imaging of primary Drosophila melanogaster neurons and physical modelling, we found that +end out microtubules are less likely to undergo catastrophe near the advancing axon tip, leading to their persistent long-term growth. In contrast, oppositely oriented microtubules remain short. Using chemical and physical perturbations of microtubule growth and genetic perturbations of the anti -catastrophe factor p150, which was enriched in the distal axon tip, we confirmed that the enhanced growth of +end out microtubules is critical for achieving uniform microtubule orientation. Computer simulations of axon development mimicking the enhanced +end out microtubule growth identified here along with previously proposed mechanisms correctly predicted the long-term evolution of axonal microtubule orientation as found in our experiments, highlighting the importance of the reduced catastrophe rate of +end out microtubules near the advancing axon tip in establishing uniform microtubule polarity. Our study thus leads to a holistic explanation of how axonal microtubules orient uniformly, a prerequisite for efficient long-range transport essential for neuronal functioning.

cell biology↗