The Notch1 intracellular domain orchestrates mechanotransduction of fluid shear stress

Life Science Alliance · 2026-01-24 · 1 citations

Hemodynamic shear stress regulates endothelial phenotype through activation of Notch1 signaling, yet the mechanistic basis for this activation is unclear. Here, we establish a fluid shear stress-dependent mechanism of Notch1 activation that is distinct from canonical ligand trans-endocytosis. Application of unidirectional laminar flow triggers the rapid spatial polarization of full-length Notch1 heterodimers into downstream membrane microdomains. Unlike canonical transactivation, Notch1 receptors are cis-endocytosed into the receptor-bearing cell within polarized microdomains. We discover that the Notch1 intracellular domain critically orchestrates receptor polarization and proteolytic cleavage in response to flow, but is dispensable for canonical ligand transactivation. Shear stress increases intracellular domain interaction with annexin A2 and caveolar proteins, which control Notch1 cis-endocytosis and proteolytic activation. These findings define a flow-specific Notch1 mechanotransduction mechanism linking receptor polarization and endocytosis with proteolytic activation and illuminate a new pathway by which mechanical forces integrate with Notch receptor activation.

The Notch1 intracellular domain orchestrates mechanotransduction of fluid shear stress

UNC Libraries · 2026-02-13

Fluid shear stress mechanotransduction by Notch1: flow stimulates Notch1 intracellular domain interactions to polarize receptors into microdomains, driving endocytosis and proteolytic activation.Hemodynamic shear stress regulates endothelial phenotype through activation of Notch1 signaling, yet the mechanistic basis for this activation is unclear. Here, we establish a fluid shear stress–dependent mechanism of Notch1 activation that is distinct from canonical ligand trans-endocytosis. Application of unidirectional laminar flow triggers the rapid spatial polarization of full-length Notch1 heterodimers into downstream membrane microdomains. Unlike canonical transactivation, Notch1 receptors are cis-endocytosed into the receptor-bearing cell within polarized microdomains. We discover that the Notch1 intracellular domain critically orchestrates receptor polarization and proteolytic cleavage in response to flow, but is dispensable for canonical ligand transactivation. Shear stress increases intracellular domain interaction with annexin A2 and caveolar proteins, which control Notch1 cis-endocytosis and proteolytic activation. These findings define a flow-specific Notch1 mechanotransduction mechanism linking receptor polarization and endocytosis with proteolytic activation and illuminate a new pathway by which mechanical forces integrate with Notch receptor activation.

Nuclear SUN2 coordinates endothelial cell-matrix interactions to regulate blood vessel homeostasis and barrier function

bioRxiv (Cold Spring Harbor Laboratory) · 2026-05-20

ABSTRACT Vascular endothelial cells respond to environmental forces to remodel vessels during development and to achieve homeostasis, and mis-regulated responses lead to vascular dysfunction and disease. The nucleus participates in force transduction to cell-matrix junctions via the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex that resides in the nuclear envelope, but how these forces are regulated and relayed is incompletely understood. We found that the LINC complex protein SUN2 is required for proper endothelial cell-matrix interactions that occur far from the nucleus and affect angiogenic expansion, vascular responses to flow, and barrier integrity. Endothelial cells lacking SUN2 had inappropriate flow responses and reduced expression of flow-mediated transcription factors in vitro and in vivo . Expression of several matrix and adhesion genes was reduced in SUN2-depleted cells, leading to defective extracellular matrix, dysmorphic focal adhesions resistant to dynamic turnover, and disturbed cell-matrix force distribution. Mechanistically, nuclear SUN2 affected dynamic regulation of the microtubule cytoskeleton that correlated with matrix metalloprotease-dependent barrier dysfunction. These findings indicate that nuclear SUN2 establishes and maintains blood vessel homeostasis by controlling microtubule-mediated effects on focal adhesion turnover and extracellular matrix properties, with implications for cardiovascular aging and diseases such as Marfan syndrome that affect vessel wall integrity.

Author response for "A Novel Manganese Glycerophosphate Vaccine Gel Elicits Broad and Durable Immunity Across an Aged and Pox Virus Model"

2026-03-22

A novel manganese glycerophosphate vaccine gel elicits broad and durable immunity across an aged and pox virus model

Nanoscale · 2026-01-01

T cells. Immunizing MnGp in 18-month-old mice elicited superior IgG and IgG1 antibody titers compared to Addavax, in addition to specific T cell responses in spleen and the draining lymph node. Finally, the co-immunization of MnGp and B5R (a vaccinia virus protein) induced higher B5R-specific antibody titers than Addavax and achieved full protection against the challenge with vaccinia virus. Overall, these findings corroborate the potential for MnGp gels as a novel vaccine platform.

A Novel Manganese Glycerophosphate Vaccine Gel Elicits Broad and Durable Immunity Across an Aged and Pox Virus Model

UNC Libraries · 2026-04-30

Subunit vaccines, composed of a protein antigen and an adjuvant, offer a safer and more versatile strategy than traditional live-attenuated vaccines, but limitations of conventional adjuvants like alum require improved design and delivery. Manganese (Mn) has emerged as a novel adjuvant that stimulates the cGAS-STING pathway, showing profound pre-clinical efficacy in vaccines against infectious diseases and cancer, but its potential dose-limiting toxicities require innovative delivery strategies. Herein, we report the development of gel derived from the generally recognized as safe (GRAS) material manganese glycerophosphate (MnGp). The gel displayed tunable controlled antigen release based on MnGp concentration that activated dendritic cells (DCs) <em>in vitro</em>, eliciting substantial production of type I interferons and upregulation of costimulatory markers. A single immunization of mice with ovalbumin (OVA) and 250 mg mL^-1 MnGp gel generated the highest and most durable OVA-specific total IgG, IgG1, and IgG2c serum antibody titers. Subsequently, a prime-boost-boost immunization with 250 mg mL^-1 MnGp gel elicited a long-lasting OVA-specific IgG, IgG1, and IgG2c sera antibody response and it was superior to MF59-mimic AddaVax and STING agonists 2,3-cGAMP. Splenocytes from mice immunized with MnGp secreted high levels of Th1-associated cytokines upon antigen recall and illustrated generation of memory CD4⁺ and CD8⁺ T cells. Immunizing MnGp in 18-month-old mice elicited superior IgG and IgG1 antibody titers compared to Addavax, in addition to specific T cell responses in spleen and the draining lymph node. Finally, the co-immunization of MnGp and B5R (a vaccinia virus protein) induced higher B5R-specific antibody titers than Addavax and achieved full protection against the challenge with vaccinia virus. Overall, these findings corroborate the potential for MnGp gels as a novel vaccine platform.

Author response for "A Novel Manganese Glycerophosphate Vaccine Gel Elicits Broad and Durable Immunity Across an Aged and Pox Virus Model"

2026-02-17

The Notch1 intracellular domain orchestrates mechanotransduction of fluid shear stress

Open MIND · 2026-01-01

Fluid shear stress mechanotransduction by Notch1: flow stimulates Notch1 intracellular domain interactions to polarize receptors into microdomains, driving endocytosis and proteolytic activation.Hemodynamic shear stress regulates endothelial phenotype through activation of Notch1 signaling, yet the mechanistic basis for this activation is unclear. Here, we establish a fluid shear stress&ndash;dependent mechanism of Notch1 activation that is distinct from canonical ligand trans-endocytosis. Application of unidirectional laminar flow triggers the rapid spatial polarization of full-length Notch1 heterodimers into downstream membrane microdomains. Unlike canonical transactivation, Notch1 receptors are cis-endocytosed into the receptor-bearing cell within polarized microdomains. We discover that the Notch1 intracellular domain critically orchestrates receptor polarization and proteolytic cleavage in response to flow, but is dispensable for canonical ligand transactivation. Shear stress increases intracellular domain interaction with annexin A2 and caveolar proteins, which control Notch1 cis-endocytosis and proteolytic activation. These findings define a flow-specific Notch1 mechanotransduction mechanism linking receptor polarization and endocytosis with proteolytic activation and illuminate a new pathway by which mechanical forces integrate with Notch receptor activation.

Understanding the Lymphatic System: Tissue-on-Chip Modeling

Annual Review of Biomedical Engineering · 2025-01-22 · 4 citations

The lymphatic vasculature plays critical roles in maintaining fluid homeostasis, transporting lipid, and facilitating immune surveillance. A growing body of work has identified lymphatic dysfunction as contributing to the severity of myriad diseases and to systemic inflammation, as well as modulating drug responses. Here, we review efforts to reconstruct lymphatic vessels in vitro toward establishing humanized, functional models to advance understanding of lymphatic biology and pathophysiology. We first review lymphatic endothelial cell biology and the biophysical lymphatic microenvironment, with a focus on features that are unique to the lymphatics and that have been used as design parameters for lymphatic-on-chip devices. We then discuss the state of the art for recapitulating lymphatic function in vitro, and we acknowledge limitations and challenges to current approaches. Finally, we discuss opportunities and the need for further development of microphysiological lymphatic systems to bridge the gap in model systems between lymphatic cell culture and animal physiology.

Author response for "Endothelial-smooth muscle microgauges for modeling pulmonary arterial vasoregulation"

2025-08-09