Columbia Undergraduate Science Journal

Cardiac Regeneration: A Promising Future For Tissue Engineering and Cardiac Repair

Krishay Patel — 2025-07-17

Cardiovascular diseases are the leading cause of human death worldwide. These diseases have detrimental effects on the heart, damaging the tissue and disrupting healthy heart function. Cardiac functioning begins to dissipate as a result of cardiac cell death and subsequent damage to the structures of the heart. Cardiac regeneration is an evolving field in cardiac therapy that aims to rebuild damaged cardiac tissue that may have previously been beyond repair. Understanding how cardiac cells function within the heart is crucial in studying tissue engineering and cardiac regeneration. With the loss of cardiac cells following cardiovascular disease, the ability to extract healthy cardiac cells for tissue engineering becomes greatly limited. Thus, tissue cultures and cellular reprogramming become crucial methods for in vitro expansion of healthy cells. Understanding regeneration in the heart, cell sources necessary for cardiac regeneration, and the existing models that have been implemented for cardiac regeneration are crucial in advancing its study and improving methods to take cardiac regeneration to clinical trials. Imaging techniques to model patient-specific structures of the heart will ultimately help map damaged tissue, assisting with the entire regeneration process. Investigating the limitations of these techniques is equally important to improving cardiac regeneration, with the possibility to save countless lives.

Design of a Genetically Encoded Tool to Study the Function of Mitochondria–Lysosome Interactions

Yuliia Kohut — 2025-07-17

Membrane contact sites (MCS) are regions of close proximity between organelles that mediate crucial organelle functions. However, the list of effective biological tools to study MCS function still needs expansion. Mitochondria and lysosomes are organelles whose dysfunction is closely associated with Parkinson’s disease (PD) pathology, and some PD-associated genes has been shown to play a role in mitochondria-lysosome contact regulation. Our work presents a novel biosynthetic system for reversible induction of interactions between mitochondria and lysosomes, leveraging abscisic-acid (ABA)-mediated heterodimerization of ABI and PYL protein domains from Arabidopsis thaliana. We engineered combinations of genetically-encoded protein heterodimer constructs each containing the ABI or PYL domain, a fluorescent protein tag (EGFP, mCherry, iRFP, or BFP), and a transmembrane sequence targeting the lysosomal membrane or outer mitochondrial membrane. Using confocal microscopy to visualize organelle colocalization, we show efficient and reversible induction of mitochondria-lysosome contacts with our ABA-responsive system. Our findings indicate that mitochondrial constructs tagged with mCherry and iRFP effectively mediate ABA-induced mitochondria-lysosome colocalization when paired with lysosomal constructs tagged with EGFP/BFP or lacking a fluorescent tag. In live-cell imaging experiments, we show that mitochondria-lysosome contact durations are tunable with this system, increasing proportionally with ABA concentration used. Overall, our system of ABA-induced reversible organelle interactions is positioned as a powerful biological tool for studying organelle dynamics and MCS functions, with relevance to therapeutic strategies in neurodegenerative disorders and organelle dysfunction.

Unveiling Dark Matter in a Galaxy: A Case Study of NGC 1068

Seonyu Lee — 2025-07-17

The dark matter distribution in NGC 1068 is analyzed by determining its mass using dynamical mass from HI-based rotation curves and stellar mass from spectral energy distribution fitting of ugriz photometric data. High-precision photometry was achieved through Gaussian fitting, star masking, 3-sigma clipping, and error propagation, enabling robust flux measurements for spectral energy distribution analysis with CIGALE. Beyond 1.5 kpc, the dynamical mass begins to exceed the stellar mass. As the error bars do not overlap, the presence of dark matter is confirmed. The difference between the two masses is used to map the dark matter distribution from 1.5 kpc to 13 kpc. This study reproduces earlier findings using high-resolution data. Furthermore, the method for constraining dark matter distributions in individual galaxies and provides detailed spectral energy distribution results with uncertainties is refined.