Tzung K. Hsiai

Cerebral venous sinus thrombosis (CVST) and carotid web (CW) are distinct cerebrovascular disorders where vascular geometry, disturbed hemodynamics, and endothelial activation interact to drive thrombosis. Both conditions disproportionately affect women, yet remain understudied because of the inability of traditional platforms to replicate complex three-dimensional lumen profiles. This perspective positions light-based lithography as a powerful biofabrication strategy for patient-specific modeling. Digital light processing and volumetric bioprinting render enclosed, perfusable hydrogel networks with high-fidelity surface topography. When integrated into dynamic vessel-on-chip perfusion loops guided by clinical imaging and computational fluid dynamics, these platforms simulate pathological flow stasis and recirculation zones, heterogeneous shear-stress gradients, and site-specific cellular aggregation. This biofabrication approach enables personalized disease modeling and translationally relevant risk assessment, providing a critical platform for advancing women’s cerebrovascular health.

BACKGROUND: MGP (matrix Gla protein) serves as an inhibitor of vascular calcification by limiting elastin degradation and regulating BMP (bone morphogenetic protein) activity. Mutation of the conserved proline residue 64 to glycine in MGP abolishes BMP binding in vitro. We hypothesized that selective loss of BMP binding would elucidate the contribution of BMP to cell differentiation in Mgp -deficient mice. METHODS: Computational analyses using AlphaFold3 and molecular dynamics simulations were performed to determine the structural effects of γ-carboxylation and the proline residue 64 to glycine mutation. The vascular phenotype of Mgp -knockin mice expressing the proline residue 64 to glycine mutation was compared with wild-type (WT) and global Mgp -knockout mice. Proximity ligation assay was performed to assess MGP-BMP4 in aortic cells. Single-cell RNA-sequencing was used to identify cellular alterations in the vascular media. RESULTS: Molecular dynamics simulation revealed 5 Ca ²⁺ ions coordinated by γ-carboxylated Glu residues in the MGP dimer. The proline residue 64 to glycine mutation did not disrupt Ca ²⁺ binding but likely suppressed conformational changes required for BMP4 binding. Unlike Mgp - KO mice, Mgp -knockin mice did not develop vascular calcification, elastic lamina proteolysis, and endothelial-mesenchymal transition, but exhibited vascular fibrosis. MGP-BMP4 interaction observed in WT aortic cells was barely detectable in Mgp -knockin aortic cells. Single-cell RNA-sequencing revealed increased fractions of smooth muscle cells and enhanced myofibroblast differentiation in the Mgp -knockin aortas compared with WT. In Mgp -knockin aortas, SMAD2 expression was significantly increased throughout the vessel wall compared with WT aortas. In contrast, SMAD1/5/9 activation in the Mgp -knockout aortas was more confined to the endothelium, whereas it localized to the media-adventitia transition in WT and Mgp -knockin aortas. Both Mgp -knockin and Mgp -knockout mice developed arteriovenous malformations in the lungs, kidneys, and brain. CONCLUSIONS: Our findings suggest that MGP plays a versatile role in preserving vascular integrity, in part serving as an important BMP-trap aimed at directing vascular cell differentiation.

Background: Differential growth between the left (LV) and right ventricles (RV) is a cornerstone of normal heart morphogenesis after birth, leading to the relatively larger and dominant LV over RV in the adult heart regarding size and function. Yet, little is known about the factors that regulate this chamber-specific growth. Methods: We used both loss-and gain-of-function mouse models, achieved through genetic or pharmacological manipulation of IRE1α or Xbp1 in cardiomyocytes. We also used primary cultured neonatal cardiomyocytes to explore the roles of IRE1α, spliced Xbp1 (sXbp1: activated form), and newly identified sXbp1 downstream targets. In addition, we generated heart-specific mosaic mutant mouse models using CRISPR/Cas9/AAV9-based somatic mutagenesis to elucidate the roles of sXbp1 downstream targets in cardiomyocytes. Results: Pharmacological inactivation of IRE1α and genetic depletion of Xbp1 resulted in a smaller LV size, due to decreased cardiomyocyte proliferation and hypertrophic growth, as well as increased cardiomyocyte death. These effects were not observed in the RV. Cardiomyocyte-specific induction of IRE1α or sXbp1 led to increased ventricular size in both ventricles, through enhanced cardiomyocyte proliferation and hypertrophic growth in both LV and RV, and reduced apoptosis in the RV. We identified two ER resident transmembrane proteins, Vimp and Rpn2, as direct binding partners of sXbp1 in targeted gene regulation at the chromatin level. CRISPR/Cas9/AAV9-based somatic mutagenesis mouse models for Vimp and Rpn2 revealed that both genes regulate cardiomyocyte proliferation, hypertrophic growth, and death. We also observed accumulated misfolded proteins in these two mutant hearts. Conclusions We demonstrate that the IRE1α-Xbp1-Vimp/Rpn2 axis regulates differential ventricular size between LV and RV during postnatal development by orchestrating cardiomyocyte proliferation, hypertrophic growth, and death through regulating protein homeostasis. Clinical Perspective: What Is New: IRE1α-Xbp1 axis is dominantly activated in the LV cardiomyocyte during the postnatal period in mouse heart. IRE1α-Xbp1 mediated ER stress signaling increases cardiomyocyte proliferation and hypertrophic growth and decreases apoptosis in the postnatal period. Activated Xbp1 directly regulates LV-specific cardiomyocyte protein homeostasis via interaction with ER membrane targeted Vimp and Rpn2. What Are the Clinical Implications?: Differential heart growth patterns between the LV and RV are critical for normal morphogenesis and function of each ventricle. Control of protein homeostasis by modulating ER stress signaling could be a potential therapeutic approach for single-chamber heart diseases.

Non-invasive monitoring of deep-tissue physiological processes from the body surface is technically challenging due to rapid signal attenuation and severe motion artefacts, primarily caused by high contact impedance and mechanical mismatch in conventional electrodes. Here we directly spray-coat a biocompatible two-dimensional nanosheet ink onto the human body, forming microscopically conformal van der Waals thin films that are intrinsically stretchable and mechanically adaptive to non-Euclidean, hairy and dynamically evolving body surfaces, thereby creating electrically functionalized body surfaces. Compared with commercial solutions, the resulting electrically functionalized body surface exhibits substantially lower contact impedance and markedly reduced extrinsic motion artefacts, enabling reliable bioelectrical signal acquisition from irregular body surfaces and robust monitoring of biopotential and bioimpedance modulations associated with deep-tissue physiological processes, including blood circulation, muscle movement and brain activity. This technology advances capability for continuous, non-invasive monitoring of deep-tissue activities during routine body movements.

How chamber-specific hemodynamic shear forces coordinate the spatial and temporal patterning of cardiac valves remains poorly understood. The zebrafish atrioventricular (AV) valve transitions from 2-cusp to 4-cusp at 14 days post-fertilization (dpf) through commissural remodeling, differential cell proliferation, and chondrogenic matrix secretion. Orthogonal valvular axes are present at 25 hpf (hours), preceding endocardial cushion formation. AV canal remodeling aligns the shear stress with leaflet formation at 48 hpf and 14 dpf. At 28 hpf, the ventricle develops functional syncytium, while the atrial peristalsis remains and is necessary for the Klf2a-Snai1b signaling in Notch-negative and ccm1 -positive endocardial cells. Without atrial contraction, the 2-to 4-cusp transition (86.7%) fails to occur. In the absence of ventricular contraction and relaxation, the formation of the first pair of leaflets (100%) does not initiate. As a corollary, we demonstrate that KLF4/SNAI1 expression at the commissure is conserved in the mammalian AV 2- to 4-cushion transition.

Plastic-derived micro- and nanoplastics are pervasive, but how environmentally aged particles affect vascular barriers is poorly understood. We hypothesized that photoaged plastics impair endothelial force-sensing, triggering gut-brain-heart barrier failure. Ultraviolet (UV) exposure converted pristine nanoplastics into oxidized, irregular photoaged microplastic aggregates (> 1.2 um). In human aortic endothelial cells, photoaged particles increased membrane stiffness and activated transcriptional programs linked to permeability, junction disruption, inflammation, and cytoskeletal remodeling. Mechanistically, photoaged particles selectively inhibited Piezo1-mediated Ca2+ signaling and downstream Notch activity without changing PIEZO1 expression, and endothelial CRISPR inhibition of PIEZO1 recapitulated these effects. In zebrafish, photoaged plastic exposure increased gut-vascular permeability and systemic spread with brain and heart accumulation, accompanied by reduced neurovascular and myocardial Ca2+ signals, depressed cardiac contractility, and abnormal locomotor behavior. Thus, photoaged plastics compromise vascular barriers through disrupted endothelial Piezo1-Notch mechanotransduction.

Invariant natural killer T (iNKT) cells are a unique subset of T lymphocytes with allogeneic potential and strong solid tumour-homing capacity, making them attractive for cancer immunotherapy. Unlike conventional T cells, iNKT cells recognize lipid antigens presented by the non-polymorphic CD1d molecule. Chimaeric antigen receptor (CAR)-redirected iNKT (CAR-iNKT) cells have shown promise; however, their clinical efficacy is limited by insufficient activation and poor long-term persistence within the tumour microenvironment. Here we describe the iNKT cell-targeted microparticle recruitment and activation system (iMRAS), a biomimetic platform engineered to locally recruit, activate and expand CAR-iNKT cells in vivo. Acting as an in vivo 'charging station', iMRAS provides chemotactic and activating cues that enhance CAR-iNKT cell functionality, improving persistence and tumour control in preclinical lymphoma and melanoma models. Through its biomimetic design and localized immunostimulatory effects, iMRAS helps overcome the limitations of current therapies for solid tumours, establishing a robust platform for advancing CAR-iNKT cell-based cancer immunotherapy.