Biology subjects

Hintze, M.

Publications and source records attributed to Hintze, M..

10 recordsLinked to original sources

bioRxiv2026

PIEZO1 upregulation in spinal cord astrocytes during MOG 35-55 -induced EAE correlates with ECM remodeling

BackgroundExtracellular matrix (ECM) remodeling is increasingly recognized as an important component of neuroinflammatory pathology in multiple sclerosis (MS), yet the mechanisms by which CNS cells sense and respond to alterations in their mechanical environment and the spatial across which mechanical changes can influence cellular behavior remain poorly understood. Piezo1 is a mechanosensitive ion channel that regulates cellular responses to mechanical stimuli and has recently emerged as a potential modulator of neuroinflammation. MethodsExperimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 wildtype mice using myelin oligodendrocyte glycoprotein (MOG):35-55. Immunohistochemical analyses were performed in spinal cord gray matter (GM), normal-appearing white matter (NAWM), and white matter lesion (LES) regions to assess ECM remodeling, total Piezo1 expression, and astrocyte-specific Piezo1 expression during acute and chronic EAE stages. Correlations with clinical EAE severity were determined. In parallel, mixed primary murine glial cultures were exposed to substrates of different stiffness and analyzed by transcriptomic profiling to investigate mechanobiological responses in vitro. ResultsECM-associated proteins, including glial fibrillary acidic protein (GFAP), fibronectin-1 and matrix metalloproteinase-3 (MMP3), were regionally upregulated during EAE, indicating widespread tissue remodeling beyond focal inflammatory lesions. Total Piezo1 expression was increased within lesions and transiently elevated in GM, whereas astrocyte-specific Piezo1 remained persistently upregulated during both acute and chronic EAE. Astrocytic Piezo1 expression correlated closely with ECM remodeling and clinical EAE severity, particularly in GM and NAWM. Notably, both total and astrocyte-specific Piezo1 showed stronger associations with clinical disability than classical inflammatory markers. Transcriptomic analysis revealed pronounced stiffness-dependent responses in glial cells, including alterations in extracellular matrix organization, cytokine signaling, cell adhesion, and proliferative pathways. ConclusionsOur findings identify astrocytic Piezo1 as a prominent component of neuroinflammatory tissue remodeling during EAE. The close association of Piezo1 with ECM alterations, clinical disease severity, and stiffness-dependent glial responses supports a link between neuroinflammation and mechanosensory signaling. These results highlight mechanosensation as a potentially important contributor to CNS pathology and establish Piezo1 alteration as a candidate biomarker for neuroinflammatory disease.

Cell Biology↗

bioRxiv2026

Spatial scale of indentation explains shift in ratio between spinal cord gray and white matter stiffness

The structural integrity of spinal cord tissue and the transmission of mechanical stimuli across the different levels of tissue microarchitecture and varying spatial scales of mechanical loading challenge experimental and computational efforts to accurately model, simulate and interpret tissue mechanics, leading to conflicting findings in existing literature. Here, we demonstrate that the bead size used in spherical indentation tests significantly affects the stiffness ratio of spinal cord gray to white matter, a dependence which we only observe on the transverse plane and not the coronal plane of the tissue. Our study reveals a shift in stiffness ratio such that for smaller spherical indenters gray matter is stiffer than white matter, while for larger indenters, white matter is stiffer than gray matter. The mean relative change from the 100 {micro}m bead to the 500 {micro}m bead differed between anatomical planes, with transverse sections showing a decrease in gray matter (-13.3%) and an increase in white matter stiffness (+26.9%), accompanied by a reduction in the gray-to-white matter stiffness ratio from 1.07 to 0.76, whereas coronal sections exhibited increases in both gray (+21.0%) and white matter (+33.8%), along with a change in the ratio from 0.99 to 1.14. These findings contribute to explaining previously contradictory results in the literature and underscore the relevance of spatial scales in mechanical characterization studies.

biophysics↗

bioRxiv2026

HDAC1/2-mediated repression of Wnt receptor expression orients asymmetric division polarity in C. elegans.

Asymmetric cell division generates distinct daughter cells essential for tissue development, yet the mechanisms orienting division polarity within tissues remain incompletely understood. Here, we uncover a role for chromatin-mediated transcriptional repression in controlling polarity orientation during asymmetric division of C. elegans epidermal stem cells, known as the seam cells. We show that tissue- specific loss of the class I histone deacetylase hda-1, homologous to mammalian HDAC1/2, causes reversals in division polarity and reduces molecular asymmetry between daughter cells. Using Targeted DamID to profile HDA-1 genomic occupancy, we identify the Wnt receptors lin-17/Frizzled and cam-1/Ror as key targets. Single- molecule FISH reveals that these receptors display striking expression gradients along the body axis, with cam-1 enriched anteriorly and lin-17 posteriorly. In hda-1 mutants, both receptors are upregulated so that differences between seam cells are flattened. Overexpression of either receptor alone is sufficient to reproduce the polarity reversals observed in hda-1 mutants, and their co-overexpression produces additive defects. The polarity phenotype is independent of the canonical NuRD and SIN3 complexes, suggesting that HDA-1 acts through an alternative mechanism to regulate Wnt receptor expression. Our findings establish a direct link between histone deacetylase activity and Wnt receptor expression and support a model in which graded expression of Wnt receptors provides positional cues that orient asymmetric division polarity in response to Wnt signals.

developmental biology↗

bioRxiv2024

Permissive and instructive Hox codes govern limb positioning

The positioning of limbs along the anterior-posterior axis varies widely across vertebrates. The mechanisms controlling this feature remain to be fully understood. For over 30 years, it has been speculated that Hox genes play a key role in this process but evidence supporting this hypothesis has been largely indirect. In this study, we employed loss- and gain-of-function Hox gene variants in chick embryos to address this issue. Using this approach, we found that Hox4/5 genes are necessary but insufficient for forelimb formation. Within the Hox4/5 expression domain, Hox6/7 genes are sufficient for reprogramming of neck lateral plate mesoderm to form an ectopic limb bud, thereby inducing forelimb formation anterior to the normal limb field. Our findings demonstrate that the forelimb program depends on the combinatorial actions of these Hox genes. We propose that during the evolutionary emergence of the neck, Hox4/5 provide permissive cues for forelimb formation throughout the neck region, while the final position of the forelimb is determined by the instructive cues of Hox6/7 in the lateral plate mesoderm. Impact statementElucidation of the Hox code defining forelimb positioning provides novel insights in lateral plate mesoderm patterning and the integration of vertebrate column structure and limb positioning.

developmental biology↗

bioRxiv2023

Inference of the core gene regulatory network underlying seam cell development in Caenorhabditis elegans

Gene regulatory networks are fundamental in cellular decision-making, yet even in well-studied systems, their topologies are often poorly characterised. The nematode Caenorhabditis elegans contains a population of stem-like cells, known as seam cells. While seam cells are essential to generate the majority of the animal epidermis as well as specific neurons, the architecture of the underlying gene network has not been elucidated. Here, we combine experiments, mathematical modelling and statistical inference to uncover the architecture of the seam cell gene network focusing on three core transcription factors (TFs), the GATA factors ELT-1, EGL-18 and the Engrailed homolog CEH-16. We use single-molecule FISH (smFISH) to quantify TF mRNA abundance in single seam cells in both wild type and mutant backgrounds. We then predict potential TF interactions and their quantitative strengths using a combination of Modular Response Analysis, ordinary differential equations and a Bayesian model discovery approach. Taken together, our findings suggest new relationships between core TFs in seam cells and highlight an approach that can be used to infer quantitative networks from smFISH data.

systems biology↗

bioRxiv2022

A receptor tyrosine kinase regulated by the transcription factor VAB-3/PAX6 pairs with a pseudokinase to trigger immune signalling upon oomycete recognition in C. elegans

Oomycetes were recently discovered as natural pathogens of Caenorhabditis elegans and pathogen recognition alone was shown to be sufficient to activate a protective transcriptional program in the host characterised by the expression of multiple chitinase-like (chil) genes. However, the molecular mechanisms underlying oomycete recognition in animals remain fully unknown. We performed here a forward genetic screen to uncover regulators of chil gene induction and found several independent loss-of-function alleles of old-1 and flor-1, which encode receptor tyrosine kinases belonging to the C. elegans-specific KIN-16 family. We present evidence that OLD-1 is an active kinase mounting the immune response, and FLOR-1 a pseudokinase that is also required for the response and regulates the distribution of OLD-1 at the epidermal membrane. Interestingly, the old-1 locus is adjacent to the chil genes in the nematode genome, thereby revealing a genetic cluster important for oomycete-resistance. Furthermore, we identify the VAB-3/PAX-6 transcription factor known for its role in visual system development to regulate old-1 expression, and consequently the spatial pattern of the response to oomycete recognition. Taken together, our study reveals both conserved and species-specific factors shaping the response to oomycete recognition.

immunology↗

bioRxiv2021

Single-shot phase contrast microscopy using polarisation-resolved differential phase contrast

We present a robust, low-cost single-shot implementation of differential phase microscopy utilising a polarisation-sensitive camera to simultaneously acquire 4 images from which the phase gradients and quantitative phase image can be calculated. This polarisation-resolved differential phase contrast (pDPC) microscopy technique can be interleaved with single-shot imaging polarimetry.

biophysics↗

bioRxiv2020

Cryptic genetic variation in a heat shock protein shapes the expressivity of a mutation affecting stem cell behaviour in C. elegans.

A fundamental question in medical genetics is how the genetic background modifies the phenotypic outcome of key mutations. We address this question by focusing on the epidermal seam cells, which display stem cell properties in Caenorhabditis elegans. We demonstrate that a null mutation in the GATA transcription factor egl-18, which is involved in seam cell fate maintenance, is more tolerated and thus has lower expressivity in the divergent CB4856 isolate from Hawaii than the lab reference strain N2 from Bristol. We identify multiple quantitative trait loci (QTLs) underlying the difference in mutation expressivity between the two isolates. These QTLs reveal cryptic genetic variation, which acts to reinforce seam cell fate through potentiating Wnt signalling. Within one QTL region, a single amino acid deletion in the heat shock protein HSP-110 in CB4856 lowers egl-18 mutation expressivity. Our work underscores that natural variation in conserved heat shock proteins can shape mutation expressivity.

genetics↗

bioRxiv2019

A cell fate switch in the C. elegans seam cell lineage occurs through modulation of the Wnt asymmetry pathway in response to temperature increase

Populations often display consistent developmental phenotypes across individuals despite the inevitable biological stochasticity. Nevertheless, developmental robustness has limits and systems can fail upon change in the environment or the genetic background. We use here the seam cells, a population of epidermal stem cells in Caenorhabditis elegans, to study the influence of temperature change and genetic variation on cell fate. Seam cell development has mostly been studied so far in the lab reference strain (N2), grown at 20{degrees} temperature. We demonstrate that an increase in culture temperature to 25{degrees}, introduces variability in the wild-type seam cell lineage with a proportion of animals showing an increase in seam cell number. We map this increase to lineage-specific symmetrisation events of normally asymmetric cell divisions at the final larval stage, leading to the retention of seam cell fate in both daughter cells. Using genetics and single molecule imaging, we demonstrate that this symmetrisation occurs via changes in the Wnt asymmetry pathway, leading to aberrant Wnt target activation in anterior cell daughters. We find that intrinsic differences in the Wnt asymmetry pathway already exist between seam cells at 20{degrees} and this may sensitise cells towards a cell fate switch at increased temperature. Finally, we demonstrate that wild isolates of C. elegans display variation in seam cell sensitivity to increased culture temperature, although seam cell numbers are comparable when raised at 20{degrees}. Our results highlight how temperature can modulate cell fate decisions in an invertebrate model of stem cell patterning.

developmental biology↗

bioRxiv2019

PRDM1 controls the sequential activation of neural, neural crest and sensory progenitor determinants by regulating histone modification

During early embryogenesis, the ectoderm is rapidly subdivided into neural, neural crest and sensory progenitors. How the onset of lineage-specific determinants and the loss of pluripotency markers are temporally and spatially coordinated in vivo remains an open question. Here we identify a critical role for the transcription factor PRDM1 in the orderly transition from epiblast to defined neural lineages. Like pluripotency factors, PRDM1 is expressed in all epiblast cells prior to gastrulation, but lost as they begin to differentiate. We show that, unlike pluripotency factors, PRDM1 is initially required for the activation of neural, neural crest and sensory progenitor specifiers and for the downregulation of pluripotency-associated genes. In vivo chromatin immunoprecipitation reveals stage-specific binding of PRDM1 to regulatory regions of neural and sensory progenitor genes, PRDM1-dependent recruitment of the histone demethylase Kdm4a to these regions and associated removal of repressive histone marks. Once lineage determinants become expressed, they repress PRDM1, and our data suggest that PRDM1 downregulation is required for cells to maintain their identity. Thus, PRDM1 mediates chromatin modifications that directly control neural and sensory progenitor genes, and its activities switch from an activator at early stages to a repressor once neural fates have been established.

developmental biology↗