Biology subjects

Wiener, R. J.

Publications and source records attributed to Wiener, R. J..

3 recordsLinked to original sources

bioRxiv2024

Invasion of glioma cells through confined space requires membrane tension regulation and mechano-electrical coupling via Plexin-B2

Glioblastoma (GBM) is a malignant brain tumor with uncontrolled invasive growth. Here, we demonstrate how GBM cells usurp guidance receptor Plexin-B2 to gain biomechanical plasticity for polarized migration through confined space. Using live-cell imaging to track GBM cells negotiating microchannels, we reveal active endocytosis at cell front and filamentous actin assembly at rear to propel GBM cells through constrictions. These two processes are interconnected and governed by Plexin-B2 that orchestrates cortical actin and membrane tension, shown by biomechanical assays. Molecular dynamics simulations predict that balanced membrane and actin tension are required for optimal migratory velocity and consistency. Furthermore, Plexin-B2 mechanosensitive function requires a bendable extracellular ring structure and affects membrane internalization, permeability, phospholipid composition, as well as inner membrane surface charge. Together, our studies unveil a key element of membrane tension and mechanoelectrical coupling via Plexin-B2 that enables GBM cells to adapt to physical constraints and achieve polarized confined migration.

cancer biology↗

bioRxiv2023

Intrinsic Mechanics of Human Stem Cell Derived Aortic Smooth Muscle Cells Support a Developmental Basis for Aneurysm Localization in Marfan Syndrome

Marfan Syndrome (MFS), a connective tissue disorder caused by a mutation in the fibrillin-1 gene, occurs in approximately 1 in 5,000 people worldwide. As an important constituent of the extracellular matrix, mutated fibrillin-1 in Marfan Syndrome leads to aortic medial degeneration, aneurysm, and dissection. TGF{beta} in the matrix, which is controlled by fibrillin-1, is known to cause pathological effects in smooth muscle cells (SMCs) within the aortic wall during MFS. TGF{beta} as well as other cytokines have been shown to impact neural crest derived SMCs differently than mesodermal derived SMCs. Furthermore, outcomes of variable cytokine responsiveness of neural crest SMCs are compounded by genetically imposed changes to neural crest SMC integrin distributions in MFS. Thus, it has been hypothesized that neural crest derived SMCs, which give rise to ascending aortic SMCs, are intrinsically mechanically susceptible to aneurysm formation in MFS. This hypothesis has been linked to the clinical observation of aneurysm formation preferentially occurring in the ascending versus descending aorta in MFS. We aim to test the hypothesis that aortic smooth muscle cells (ASMCs) have intrinsic mechanobiological properties which cause cell weakening in Marfan Syndrome. Human induced pluripotent stem cells (hiPSC) from Marfan patients and healthy volunteers were differentiated into either ascending- or descending-ASMCs via their respective developmental lineages, and cultured to either an early (6 days) or late (30 days) stage of post-differentiation maturation. Mass spectrometry-based proteomics of early-stage iPSC-ASMCs revealed an array of depleted proteins unique to MFS ascending-SMCs that were associated with cell mechanics and aortic aneurysm. Targeted examination of the proteomics dataset revealed intracellular proteins (ACTA2, CNN1, TAGLN) were significantly depleted in MFS ascending-ASMCs. The intrinsic, matrix-independent, hiPSC-ASMC stiffness quantified by atomic force microscopy (AFM) revealed that MFS ascending-ASMCs, but not descending-ASMCs, were significantly less stiff than healthy, at the late cell-maturation stage (p<0.0005). Late-stage ascending- and descending-ASMCs also showed clear functional impairments via calcium flux in MFS. AFM revealed a similar mechanical phenotype in early-stage ASMCs, with MFS ascending-ASMCs, but not descending-ASMCs, being significantly less stiff than healthy (p<0.005). In summary, this study supports an emerging hypothesis of ontogenetic predisposition for aneurysm susceptibility in Marfan Syndrome based on locally altered mechanobiology of developmental origin-specific ASMC subtypes. This may lead to new cell-targeted approaches for treating aortic aneurysm in patients with MFS.

biophysics↗

bioRxiv2019

Plexin-B2 is a key regulator of cell mechanics during multicellular organization

During multicellular organization, individual cells need to constantly respond to environmental cues and adjust contractile and adhesive forces in order to maintain tissue integrity. The signaling pathways linking biochemical cues and tissue mechanics are unclear. Here, we show that Plexin-B2 regulates mechanochemical integration during multicellular organization. In human embryonic stem cells (hESCs), Plexin-B2 controls cell shape and tissue geometry in both 2D epithelial colony and 3D spheroid aggregates by regulating actomyosin contractility and junctional/cell-matrix adhesive properties. Atomic force microscopy (AFM) directly demonstrates that Plexin-B2 modulates cell stiffness in hESC colonies, which in turn impacts cell proliferation and cell fate specification through {beta}-catenin signaling and YAP mechanosensing. YAP also functions as a mechanoregulator downstream of Plexin-B2, thus forming a mechanochemical integrative loop. In human neuroprogenitor cells (hNPCs), Plexin-B2 similarly controls cell stiffness and tensile forces, as revealed by AFM and FRET tension sensor studies. Strikingly, Plexin-B2-deficient hNPCs display accelerated neuronal differentiation. From an organogenesis perspective, Plexin-B2 maintains cytoarchitectural integrity of neuroepithelium, as modeled in cerebral organoids. On a signaling level, Plexin-B2 engages extracellular as well as intracellular Ras-GAP and RBD domains for mechanoregulation through Rap and Rac GTPases. Our data unveil a fundamental function of Plexin-B2 for mechanochemical integration during multicellular organization, and shed light on the principle of force-mediated regulation of stem cell biology and tissue morphogenesis.

developmental biology↗