Date of Completion

Spring 4-28-2021

Thesis Advisor(s)

Ernesto Canalis; Karen Menuz

Honors Major

Physiology and Neurobiology

Disciplines

Cells | Congenital, Hereditary, and Neonatal Diseases and Abnormalities | Medical Genetics | Musculoskeletal System | Nucleic Acids, Nucleotides, and Nucleosides | Tissues

Abstract

NOTCH2 is a transmembrane receptor that is part of the Notch receptor family, known for controlling cell differentiation and function. Notch receptors play a crucial role in skeletal development and bone homeostasis. Hajdu Cheney Syndrome (HCS) is a rare monogenic disorder affecting the skeleton caused by a gain-of-function mutation in NOTCH2. Antisense oligonucleotides (ASO) are sequence-specific single-stranded nucleic acids that bind to target mRNA and initiate mRNA degradation. While previous work has explored the role of Notch2 ASOs in osteoblasts and osteoclasts, this paper explores the role of Notch2 and Notch2 ASOs in cells of cartilage tissue. The effect of Notch2 ASOs on Notch2 were tested in chondrocytes of a murine model of HCS (Notch2tm1.1Ecan) in vitro and in vivo. Notch2 ASO downregulated Notch2 in chondrocytes of both Notch2wt/wt mice and Notch2tm1.1Ecan mice. Notch target genes Hes1, Hey1, Hey2, and HeyL were amplified in Notch2tm1.1Ecan mice, indicating the presence of the HCS gain-of-function Notch2 mutation. Notch2 ASOs significantly downregulated Notch2 and Notch target genes in chondrocytes from Notch2tm1.1Ecan mice. The mutant gene Notch26955C>T was only detected in Notch2tm1.1Ecan mice and was downregulated by a mutant specific Notch26955C>T ASO. In conclusion, Notch2 ASOs successfully downregulate Notch2, Notch26955C>T, and Notch target genes in mouse chondrocytes.

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