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  • Data for Impact of Acute Endurance Exercise on Alternative Splicing in Skeletal Muscle

    work
    Creator:
    Ludlow, Andrew and Ahn, Alexander
    Description:
    Publicly accessible short-read RNA sequencing (SRS) of clinical exercise studies were extracted from the Gene Expression Omnibus. Oxford Nanopore long-read RNA sequencing (LRS) was performed on mouse gastrocnemius before and following treadmill exercise. Differential gene expression (DGE), differential alternative splicing (DAS), and differential isoform expression (DIE) were analyzed. Gel-based/droplet digital RT-PCR and western blots were performed to validate expression changes of select genes. Both SRS and LRS illustrated significant DGE in skeletal muscle post-exercise, whereby 89 RBPs were significantly up-/down-regulated. rMATS analysis of SRS data revealed that exon-skipping and intron-retaining splicing events were the most common. Swan analysis of LRS data revealed 61 RBPs with significant isoform switching: one of these RBPs, mHnrnpa3, underwent a significant non-coding to protein-coding switch. HnRNP-A3 protein levels validated nearly two-fold increases at 1 hour and 24 hours post-exercise.
    Keyword:
    Alternative splicing and Exercise
    Citation to related publication:
    Impact of Acute Endurance Exercise on Alternative Splicing in Skeletal Muscle. Alexander Ahn, Jeongjin J. Kim, Aaron L. Slusher, Jeffrey Y. Ying, Eric Y. Zhang, Andrew T. Ludlow bioRxiv 2024.11.21.624690; doi:  https://doi.org/10.1101/2024.11.21.624690
    Discipline:
    Health Sciences

  • Data for Discovery and characterization of a novel telomerase alternative splicing isoform that protects lung cancer cells from chemotherapy induced cell death.

    work
    Creator:
    Ludlow, Andrew
    Description:
    Single molecule long read RNA/cDNA sequencing of TERT revealed 45 TERT mRNA variants including 13 known and 32 novel variants. Among the variants, TERT Delta 2-4, which lacks exons 2-4 but retains the original open reading frame, was selected for further study. Induced pluripotent stem cells and cancer cells express higher levels of TERT Delta 2-4 compared to primary human bronchial epithelial cells. Overexpression of TERT Delta 2-4 enhanced clonogenicity and resistance to cisplatin-induced apoptosis. Knockdown of endogenous TERT Delta 2-4 in Calu-6 cells reduced clonogenicity and resistance to cisplatin. Our results suggest that TERT Delta 2-4 enhances cancer cells’ resistance to intrinsic apoptosis. RNA sequencing following knockdown of Delta 2-4 TERT indicates that translation is downregulated and that mitochondrial related proteins are upregulated compared to controls.
    Keyword:
    TERT, Alternative splicing, Telomere, and Telomerase
    Citation to related publication:
    Kim, J.J., Ahn, A., Ying, J.Y. et al. Discovery and characterization of a novel telomerase alternative splicing isoform that protects lung cancer cells from chemotherapy induced cell death. Sci Rep 15, 6787 (2025).  https://doi.org/10.1038/s41598-025-90639-3
    Discipline:
    Science

  • Dynamics of TERT Regulation via Alternative Splicing in Stem Cells and Cancer Cells

    work
    Creator:
    Ludlow, Andrew and Kim, Jeongjin
    Description:
    Part of the regulation of telomerase activity includes the alternative splicing (AS) of the catalytic subunit telomerase reverse transcriptase (TERT). Although a therapeutic window for telomerase/TERT inhibition exists between cancer cells and somatic cells, stem cells express TERT and rely on telomerase activity for physiological replacement of cells. Therefore, identifying differences in TERT regulation between stem cells and cancer cells is essential for developing telomerase inhibition-based cancer therapies that reduce damage to stem cells. In this study, we measured TERT splice variant expression and telomerase activity in induced pluripotent stem cells (iPSCs), neural progenitor cells (NPCs), and non-small cell lung cancer cells (NSCLC, Calu-6 cells). We observed that a NOVA1-PTBP1-PTBP2 axis regulates TERT alternative splicing (AS) in iPSCs and their differentiation into NPCs. We also found that splice-switching of TERT, which regulates telomerase activity, is induced by different cell densities in stem cells but not cancer cells. Lastly, we identified cell type-specific splicing factors that regulate TERT AS. Overall, our findings represent an important step forward in understanding the regulation of TERT AS in stem cells and cancer cells. These data and subsequent studies may reveal a splicing factor(s) or their binding site(s) that could be targeted with small molecule drugs or antisense oligonucleotides, respectively, to reduce telomerase activity in cancer cells and promote durable cancer remissions.
    Keyword:
    Telomere, telomerase, TERT, alternative RNA splicing
    Citation to related publication:
    Kim JJ, Sayed ME, Ahn A, Slusher AL, Ying JY, et al. (2023) Dynamics of TERT regulation via alternative splicing in stem cells and cancer cells. PLOS ONE 18(8): e0289327.  https://doi.org/10.1371/journal.pone.0289327
    Discipline:
    Science