Dr. Merlin Nithya Gnanapragasam

The overarching goal of our laboratory is to delineate the processes that regulate tissue proliferation and differentiation, and how dysregulation of these pathways contributes to human diseases. Our studies utilize erythroid cells as a model system, and investigate transcriptional and posttranscriptional regulation of erythropoiesis and hemoglobin gene regulation.

Enucleated red blood cells constitute 80% of cells in the body. A precise balance between self-renewal divisions and terminal differentiation is essential for maintaining this enormous pool of cells. Terminal erythroid differentiation is particularly unique in that the differentiation program is coupled to 3-4 rapid terminal cell divisions with peculiarly short G1 phase and fast DNA replication compared to self-renewal divisions. We do not yet understand the processes that regulate the timing, integrity, and the numbers of these rapid terminal divisions. Dysregulation of these terminal divisions leads to impairment of terminal erythroid differentiation and diseases such as Congenital Dyserythropoietic Anemia (CDA), a severe anemia characterized by increased proportions of binucleated erythrocytes.

Terminal erythroid differentiation is accompanied by a robust synthesis of hemoglobin, the oxygen transport protein that constitutes 95% of the protein content in red blood cells. At birth, the hemoglobin composition switches from fetal to adult type globins, a process known as hemoglobin switching. In genetic disorders such as sickle cell anemia and beta thalassemia, the adult type beta globin is affected, and re-expressing the fetal type beta globin has been shown to ameliorate the disease. Therefore, understanding the processes that regulate hemoglobin switching can contribute towards developing cures for sickle cell anemia and beta thalassemia.

Our research goals are three-fold: 

1) Understand how the specialized transcriptional regulation in erythroid cells ensures that the cell cycle machinery is able to accommodate the rapid pace of the terminal cell divisions. Specifically, our lab will investigate how ubiquitous factors regulating DNA replication, centromere cohesion, and cytokinesis, cater to the specialized demands of the rapid erythroid cell divisions. 

2) Investigate the molecular pathogenesis of CDA IV, which is a severe anemia caused by a hypomorphic mutation in EKLF/KLF1 (a master regulator of erythropoiesis), that arises due to a failure in terminal cell divisions and result in binucleate erythroblasts and erythroblasts with DNA bridges. 

3) Study the transcriptional and post-transcriptional mechanisms of hemoglobin switching, to identify factors that induce fetal hemoglobin in adult erythroid cells, as this can ameliorate the symptoms in sickle cell anemia and beta thalassemia. 

Our external funding sources are NIDDK/NIH (R01, K01 awards) and Cooley's Anemia Foundation.

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Dr. Raja Sundari Sundaram PhD
Postdoctoral Fellow
r.sundaram@csuohio.edu

Anita Dhara
PhD Candiate; CMMS fellow
a.dhara@vikes.csuohio.edu

Rachael White
PhD Candiate; NHLBI CD-Cavs T32 trainee
r.a.white88@vikes.csuohio.edu

Sarah Adams
PhD Candidate; NIDDK U2C training fellow (https://case.edu/medicine/clecreatekuh/node/416)
s.adams33@vikes.csuohio.edu

Parina Patel 
PhD Student
p.n.patel86@vikes.csuohio.edu 

Sumayea Meem 
PhD Student 
s.mahmoodmeem@vikes.csuohio.edu

Complete List of Published Work in MyBibliography

Selected Publications:

Elagooz R, Dhara AR, Gott RM, Sarah AE, White RA, Ghosh AA, Ganguly S, Man Y, Owusu-Ansa A, Mian OY, Gurkan UA, Komar A, Ramamoorthy M, Gnanapragasam MN. PUM1 mediates the post-transcriptional regulation of human fetal hemoglobin. Blood Adv 2022 Dec 13;6(23):6016-6022. (Highlighted in Hematopoiesis News; Highlighted as a featured publication on NIDDK Sponsored Cooperative Centers of Excellence in Hematology website) Link

Gnanapragasam MN, Planutis A, Glassberg JA, Bieker JJ. Identification of a genomic DNA sequence that quantitatively modulates KLF1 transcription factor expression in differentiating human hematopoietic cells. Sci Rep. 2023 May 10;13(1):7589. (Highlighted in Hematopoiesis News) Link

Mukherjee M, Xue L, Planutis A, Gnanapragasam MN, Chess A, Bieker JJ. EKLF/KLF1 expression defines a unique macrophage subset during mouse erythropoiesis. Elife. 2021 Feb 11;10:e61070. Link

Gnanapragasam MN, Crispino JD, Ali AM, Weinberg R, Hoffman R, Raza A, Bieker JJ. Survey and evaluation of mutations in the human KLF1 transcription unit. Sci Rep. 2018 Apr 26;8(1):6587. Link

Gnanapragasam MN, Bieker JJ. Orchestration of late events in erythropoiesis by KLF1/EKLF. Curr Opin Hematol. 2017 May;24(3):183-190. Link

Gnanapragasam MN, McGrath KE, Catherman S, Xue L, Palis J, Bieker JJ. EKLF/KLF1-regulated cell cycle exit is essential for erythroblast enucleation. Blood. 2016 Sep 22;128(12):1631-41. (Highlighted in Hematopoiesis News). Link

Liang R, Campreciós G, Kou Y, McGrath K, Nowak R, Catherman S, Bigarella CL, Rimmelé P, Zhang X, Gnanapragasam MN, Bieker JJ, Papatsenko D, Ma'ayan A, Bresnick E, Fowler V, Palis J, Ghaffari S. A Systems Approach Identifies Essential FOXO3 Functions at Key Steps of Terminal Erythropoiesis. PLoS Genet. 2015 Oct 9;11(10). Link

*Yien YY, *Gnanapragasam MN, Gupta R, Rivella S, Bieker JJ. Alternative splicing of EKLF/KLF1 in murine primary erythroid tissues. Exp Hematol. 2015 Jan;43(1):65-70. (*Authors contributed equally). Link

Xue L, Galdass M, Gnanapragasam MN, Manwani D, Bieker JJ. Extrinsic and intrinsic control by EKLF (KLF1) within a specialized erythroid niche. Development. 2014 Jun;141(11):2245-54. Link

Jaffray JA, Mitchell WB, Gnanapragasam MN, Seshan SV, Guo X, Westhoff CM, Bieker JJ, Manwani D. Erythroid transcription factor EKLF/KLF1 mutation causing congenital dyserythropoietic anemia type IV in a patient of Taiwanese origin: review of all reported cases and development of a clinical diagnostic paradigm. Blood Cells Mol Dis. 2013 Aug;51(2):71-5 Link

Amaya M, Desai M, Gnanapragasam MN, Wang SZ, Zu Zhu S, Williams DC Jr, Ginder GD. Mi2β-mediated silencing of the fetal γ-globin gene in adult erythroid cells. Blood. 2013 Apr 25;121(17):3493-501. Link

Mian OY, Wang SZ, Zhu SZ, Gnanapragasam MN, Graham LJ, Bear HD, Ginder GD. Methyl Binding Domain Protein 2 (MBD2) Dependent Proliferation and Survival of Breast Cancer Cells. Mol Cancer Res. 2011;9(8):1152-62. Link

Gnanapragasam MN, Scarsdale JN, Amaya ML, Webb HD, Desai MA, Walavalkar NM, Wang SZ, Zu Zhu S, Ginder GD, Williams DC Jr. p66Alpha-MBD2 coiled-coil interaction and recruitment of Mi-2 are critical for globin gene silencing by the MBD2-NuRD complex. Proc Natl Acad Sci U S A. 2011 May 3;108(18):7487-92. Link

Rupon JW, Wang SZ, Gnanapragasam M, Labropoulos S, Ginder GD. MBD2 contributes to developmental silencing of the human ε-globin gene. Blood Cells Mol Dis. 2011 Mar 15;46(3):212-9. Link

Ginder GD, Gnanapragasam MN, Mian OY. The role of the epigenetic signal, DNA methylation, in gene regulation during erythroid development. Curr Top Dev Biol. 2008;82:85-116. Link