Biology subjects

Benjamin, A. C.

Publications and source records attributed to Benjamin, A. C..

4 recordsLinked to original sources

bioRxiv2026

The extracellular matrix regulates tissue mechanics to enable cyclic lymph node remodelling and sustained immunity

Tissue shape and function are defined by the mechanical interactions of cellular and extracellular components. Lymph nodes cyclically remodel in response to immune challenges whilst preserving essential tissue architecture, comprised of a stromal fibroblastic reticular cell (FRC) network and extracellular matrix (ECM) it ensheaths. We experimentally quantified the contribution of ECM to the viscoelastic properties of the FRC network to parameterise an in silico model exploring factors affecting the FRC network's adaptation to lymph node expansion. The balance between tissue pressure, FRC contractility, and ECM stiffness permit robust tissue remodelling, while maintaining physiological geometries. Local perturbation of ECM stiffness or FRC contractility disrupts force distribution and impacts FRC proliferation and tissue expansion. Spatially dispersed perturbations exert higher impact on tissue remodelling than equivalent localised perturbations, with effects propagating across the network. The lymph node provides a system for studying the integration of cellular and extracellular mechanics during dramatic tissue remodelling.

biophysics↗

bioRxiv2021

Mechanical Forces during Lymph Node Expansion Govern Fibroblastic Reticular Network Remodeling

Emergent physical properties of tissues are not readily understood by reductionist studies of their constituent cells. Here, we show molecular signals controlling cellular physical properties, collectively determining tissue mechanics of lymph nodes, an immunologically-relevant, adult mammalian tissue. Lymph nodes paradoxically maintain robust tissue architecture in homeostasis yet are continually poised for extensive tissue expansion upon immune challenge. We find that following immune challenge, cytoskeletal mechanics of a cellular meshwork of fibroblasts determine tissue tension independently of extracellular matrix scaffolds. We determine that CLEC-2/podoplanin signalling regulates the cell surface mechanics of fibroblasts, permitting cell elongation and interdigitation through expedited access to plasma membrane reservoirs. Increased tissue tension through the stromal meshwork gates the initiation of fibroblast proliferation, restoring homeostatic cellular ratios and tissue structure through expansion.

biophysics↗

bioRxiv2020

Podoplanin drives dedifferentiation and amoeboid invasion of melanoma

Melanoma is an aggressive skin cancer developing from melanocytes, frequently resulting in metastatic disease. Melanoma cells utilise amoeboid migration as mode of local invasion. Amoeboid invasion is characterized by rounded cell morphology and high actomyosin contractility driven by the RhoA signalling pathway. Migrastatic drugs targeting actin polymerization and contractility to inhibit invasion and metastasis are therefore a promising treatment option. To predict amoeboid invasion and metastatic potential, there is a need for biomarkers functionally linked to contractility pathways. The glycoprotein podoplanin drives actomyosin contractility in lymphoid fibroblasts, and is overexpressed in several cancer types. Here, we show that podoplanin enhances amoeboid invasion in melanoma. Expression of podoplanin in murine melanoma models drives rounded cell morphology, increasing motility and invasion in vivo. Podoplanin expression is upregulated in a subset of dedifferentiated human melanoma, and in vitro is sufficient to suppress melanogenesis and upregulate melanoma-associated markers Mitf and Pou3f2. Together, our data indicates that podoplanin is both a potential biomarker for dedifferentiated invasive melanoma and a promising migrastatic therapeutic target.

cancer biology↗

bioRxiv2019

Podoplanin function is switched by partner proteins on fibroblastic reticular cells

Lymph node expansion is pivotal for adaptive immunity. CLEC-2+ migratory dendritic cells (DCs) interact with fibroblastic reticular cells (FRCs) to inhibit podoplanin-dependent actomyosin contractility, permitting FRC spreading and lymph node expansion. However, the molecular mechanisms controlling lymph node remodelling are not fully understood. We asked how podoplanin is regulated on FRCs in the early phase of lymph node expansion in vivo, and further, which other FRC markers are required for FRCs to respond to CLEC-2+ DCs. We find that expression of podoplanin and its partner proteins CD44 and CD9 in FRCs is coregulated by CLEC-2, and is differentially expressed by specific lymph node stromal populations in vivo. We find that beyond contractility, podoplanin is required for polarity and alignment of FRCs. Both CD44 and CD9 act to dampen podoplanin-dependent contractility, and colocalize with podoplanin in different areas of the cell membrane. Independently of podoplanin, CD44 and CD9 affect the degree of cell-cell contact and overlap between neighbouring FRCs. Further, we show that both CD44 and CD9 are required for FRCs to spread and form protrusions in response to DCs. Our data show that remodelling of the FRC cytoskeleton is a two-step process requiring podoplanin partner proteins CD44 and CD9. Firstly, CLEC-2/podoplanin-binding drives relaxation of actomyosin contractility, and secondly FRCs form protrusions and spread which requires both CD44 and CD9. Together, we show a multi-faceted response of FRCs to DCs, which requires CD44 and CD9 in addition to podoplanin.

cell biology↗