Authors:

David An

Date Created:

Not specified

Course Title:

Professor:

Not specified

About Paper:

Atherosclerosis develops in regions of disturbed flow, such as bifurcations or curves, where endothelial cells (ECs) exhibit altered gene expression and cuboidal morphology. Suppression of kruppel-like factor 2 (KLF2), critical for EC physiology, is a hallmark of these areas. Endothelial cell size, influencing vessel diameter, perfusion, and vascular responses, is also affected by flow. Although KLF2's role in regulating EC size has been shown in zebrafish, its effects on human EC size, morphology, and downstream targets remain poorly understood. Human umbilical vein endothelial cells (HUVECs) were transduced with murine KLF2 (mKLF2) or GFP-only control vectors under static conditions. Epifluorescent imaging was used: Cellpose enabled segmentation and quantification of cell area, while PolarityJam analyzed morphological features including eccentricity, axis ratio, and orientation. NOS3 expression was quantified in four groups: Ad-GFP control, Ad-mKLF2, Ad- mKLF2 with L-NAME (an eNOS inhibitor), and Ad-GFP with L-NAME. Ad-mKLF2 cells showed a 22% increase in surface area (95% CI: 15%-26%) and adopted a more elongated morphology, a shape linked to improved alignment to shear stress and enhanced barrier function. While control cells proliferated by 29% over 48 hours (95% CI: 9%-48%), mKLF2 cells prioritized growth without division, with unchanged nuclear size ruling out senescence or DNA damage. A positive correlation between GFP intensity and cell area supports a direct role for KLF2 in modulating cell size and shape. No significant size difference between Ad-mKLF2 cells with or without L-NAME indicates eNOS is not a key determinant. We are now examining hundreds of downstream genes to further elucidate this regulatory network and identify additional pathways involved. These findings establish KLF2 as a key regulator of EC size and morphology, independent of eNOS, and lay the groundwork for future studies on additional KLF2-regulated pathways to restore vascular homeostasis and combat atherosclerosis. Exploring Textile Foldability For Origami-Inspired Structures Faith Atieno, Kausalya Mahadevan, Katia Bertoldi Harvard College | Eliot House | Mechanical Engineering | 2027 With the growing interest in soft robotics, textiles have emerged as promising materials due to their softness, breathability, flexibility, and lightweight nature, as well as their familiarity in daily life. In deployable structures, textiles can be embedded with actuators and programmed to deform into predetermined 3D shapes through specific stitch designs. This study focuses on textile foldability, defined as the ability of a fabric to transform from one shape to another under actuation, which draws inspiration from origami to convert flat sheets into 3D forms. We investigate foldability by sewing different stitch patterns onto a single fabric and observing how the material folds when actuated. The primary actuators used are heat-shrinking and water-soluble threads, which contract or dissolve under heat and water exposure to trigger folding. Once the folding behavior of a stitch pattern is established, we replicate it on various fabrics to examine how material properties affect foldability. To explore a broad range of textile behavior, we intentionally selected fabrics with distinct mechanical characteristics: chiffon, woven nylon, and quilting cotton. Our results show that both fabric type and stitch parameters significantly influence folding performance. For example, a consistent stitch pattern on woven nylon achieved a 70% folding success rate. In 7 cm-wide samples, panel gaps of 5-10 mm resulted in full folding with near-zero angles between panels, while smaller gaps (<5 mm) produced acute angles. The same stitch pattern produced noticeably different results across fabrics, demonstrating the importance of material selection. These findings offer valuable insight for the design of deployable textile structures, helping guide choices in fabric type and stitch configuration when manufacturing 2D textiles designed to fold into specific 3D shapes. Harvard Summer Undergraduate Research Village Program for Research in Science and Engineering

Source:

Harvard / Human Developmental and Regenerative Biology / 2027

Topics:

No topics listed

Co-authors:

David An