Page 25 - Hormel Institute Annual Report 2021-22

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genetics in the setting of malignancy, providing valuable insight into the evolution and reshuffling of centromeric sequences
in cancer development and progression. Currently, we are recreating these mutations occurring in cancer cells in chromo- somally normal human cells using CRISPR Cas9 to determine the effect of centromere instability on centromere assembly and function and chromosome segregation. These studies
will help us to understand the role of centromere deletion in genome instability and aneuploidy seen in cancer. In addition, we study the function of centromeric proteins in cancer.
Centromeres in Scleroderma
We are especially focused on the function of centromeres in Scleroderma. The contribution of centromere defects to Scleroderma remains unknown despite many of the
Recent Publications:
• Paul, S., Kaplan, M., Khanna, D., Saha, A. K., Tsou, P.
T., McCourt, P., Anand, M., Radecki, A., Mourad, M., Sawalha, A., Markovitz, D. M., & Contreras-Galindo, R. (2022) Centromere Defects, Chromosome Instability, and cGAS-STING Activation in Systemic Sclerosis. Nat. Commun. (In press)
• Peixoto, E., Khan, A., Lewis, Z. A., Contreras-Galindo, R., & Czaja, W. (2022). The Chromatin Remodeler HELLS: A New Regulator in DNA Repair, Genome Maintenance, and Cancer. Int J Mol Sci, 23(16), 9313.
• Paul, S., McCourt, P., Myle, L., Ryu, J., Czaja, W., Bode, A., Contreras-Galindo, R., et al. (2022). Fyn interrupts telomere maintenance in stem cells by phosphorylating menin at tyrosine 603. Research Square, (Preprint)
• Saha, A. K., Contreras-Galindo, R., Niknafs, Y. S., Iyer,
M., Qin, T., Padmanabhan, K., Siddiqui, J., Palande, M., Wang, C., Qian, B., Ward, E., Tang, T., Tomlins, S. A., Gitlin, S. D., Sartor, M. A., Omenn, G. S., Chinnaiyan, A. M., & Markovitz, D. M. (2020). The role of the histone H3 variant CENPA in prostate cancer. J Biol Chem, 295(25), 8537-8549.
centromere proteins that were discovered due to these patient-derived antibodies. Using novel genetic and cytogenetic analysis we find that affected fibroblasts from SSc patients show marked alterations in centromeric DNA regardless of receiving treatment. Strikingly, we observed “leaking” of centromere
proteins from the nucleus into the cytoplasm in all limit- ed cutaneous Scleroderma patients who have anti- centromere antibodies. Scleroderma fibroblasts showed abnormal chromosome segregation, with micronuclei that activate the cGAS-STIN pathway of autoimmunity. Surprisingly, several micronuclei no longer recruit the centromere identity protein CENPA, yet they still retain centromere sequences. Our studies reveal that centro- meric genomic instability and epigenetic defects may lead to the pathogenesis of Scleroderma. As both centromere genetics and epigenetics defects, together with an immune response to centromeres is seen
in Scleroderma patients, we are clarifying whether Scleroderma is a centromere disease with very promising findings. The projects are currently supported by the Scleroderma Foundation and the Rheumatology Research Foundation.
Colocalization of cGAS to micronuclei in SSc fibroblasts.
IF analysis of expression of cGAS (red) in SSc fibroblasts. Nuclei and micronuclei were stained in DAPI (blue). Micrographs showing cGAS expression and colocalization to micronuclei in an lcSSc patient.
Lab research activities:
https://www.hi.umn.edu/research/research-sec- tions/genome-instability-chromosome-biology/
ORCID iD: https://orcid.org/0000-0002-6284-3359