1. Functional characterization of long noncoding RNAs that regulate gene expression during development and in adulthood. As a postdoctoral fellow, I began investigating epigenetic mechanisms and modeling these mechanisms of gene expression using conditional knockout mouse models. I demonstrated that the Tsx gene does not encode for a protein but instead is transcribed as a long noncoding RNA, similar to other neighboring genes. I generated a conditional knockout mouse for Tsx and discovered that Tsx RNA has functions beyond the germline, affecting stem cell growth, expression of neighboring genes that regulate X-chromosome inactivation, and also behavior in a gender-specific fashion. This work provided a conceptual foundation for experimentally testing for coding potential of noncoding RNAs and for their functional characterization. As an associate professor, my lab continues to study epigenetic mechanisms of gene expression involving long noncoding RNAs from the X chromosome. We have also investigated sex-specific gene expression profiles during human placental development using in vitro pluripotent stem cell derived model systems. In addition, my lab continues to have a long-standing interest in functional characterization of novel X-linked long noncoding RNAs. We discovered LNCRHOXF1 which functions during early placental development.
- Anguera, M.C., Ma, W., Clift, D., Namekawa, S., Kelleher, R.J, and Lee, J.T. (2011). “Tsx produces a long noncoding RNA and has general functions in the germline, stem cells, and brain.” PLoS Genet. 7 (9):1-14. PMCID: PMC3164691
- Ian Penkala, Camille Syrett, Jianle Wang, and Montserrat C. Anguera. (2016). “LNCRHOXF1: a long noncoding RNA from the X-chromosome that suppresses viral response genes during development of the early human placenta”. Mol Cell Biol. Apr 11, 2016, PMID: 27066803
- Camille Syrett, Isabel Sierra, Corbett Berry, Daniel Beiting, and Montserrat C. Anguera. (2018) “Sex-specific gene expression during differentiation of human pluripotent stem cells to trophoblast progenitors”. Stem Cells Dev. July 11; PMID: 29993333
2. Defining abnormal X-Chromosome Inactivation maintenance in human pluripotent stem cells. During my postdoc, I also investigated human X-Chromosome Inactivation (XCI) in the pluripotent state to specifically determine whether reprogramming human female fibroblasts would reactive the inactive X chromosome. I discovered that the reprogramming process generated a heterogeneous mixture of X-Inactivation cells, distinguishable by their expression pattern for the long noncoding RNA XIST. I made the critical observation that loss of XIST RNA expression in human pluripotent stem cells results in the acquisition of cancer-like phenotypes. This work was the first to demonstrate that human female pluripotent stem cells are potentially dangerous in a clinical setting. These experiments are the basis for my current research program investigating how abnormal expression from the inactive X, resulting from aberrant XCI maintenance, is involved in female-biased autoimmunity, where X-silencing is compromised.
- Anguera, M.C., Sadreyev, R., Zhang, Z., Szanto, A., Sheridan, S., Haggerty, S., Jaenisch, R., Gimbelbrandt, A., Mitalipova, M., and Lee, J.T. (2012). “Molecular signatures and epigenetic stability of human induced pluripotent stem cells.” Cell Stem Cell 11(1):75-90. PMCID: PMC3587778
- Lessing, D., Anguera, M.C., and Lee, J.T. (2013). “X Chromosome Inactivation and Epigenetic Responses to Cellular Reprogramming.” Annu Rev Genomics Hum Genet. 14:85-110.
3. Mechanisms of X-Chromosome Inactivation in lymphocytes and other immune cells. As an associate professor at Penn, I have continued investigating the molecular mechanisms of X-Chromosome Inactivation, and how altered dosage of X-linked genes contributes to sex-biased disease. As auto-antigen driven activation of lymphocytes drives autoimmune disease we first investigated the epigenetic status of the inactive X in female lymphocytes from humans and mice, and made the remarkable discovery that these cells do not maintain X-Chromosome Inactivation in the same way as other female somatic cells. We were the first to discover that the inactive X has euchromatic features in female lymphocytes, which may underlie the female-bias in autoimmune disorders including lupus. Our research also demonstrated that T and B cells, upon antigen-mediated stimulation, exhibit relocalization of Xist RNA and heterochromatic marks to the inactive X chromosome, which we have termed ‘dynamic XCI maintenance’. My lab is investigating the molecular details of dynamic XCI maintenance in T and B cells, and has identified protein factors that are required for localization of epigenetic modifications to the inactive X.
- Wang, J., Syrett, C.M., Kramer, M. Basu, A., Atchison, M. & Anguera, M.C. (2016). “Unusual maintenance of X-chromosome Inactivation predisposes female lymphocytes for increased expression from the inactive X”. Proc Natl Acad Sci, Mar. 21, 2016. PMCID: PMC4833277
- Syrett, C.M., Sindhava, V., Hodawadekar, S., Myles, A., Liang, G., Zhang, Y., Nandi, S., Cancro, M., Atchison, M., & Anguera, M.C. (2017) “Loss of Xist RNA from the inactive X during B cell development is restored in a dynamic YY1-dependent two-step process in activated B cells”. Plos Genetics, Oct 9; 13 (10). PMCID: PMC5648283
- Camille Syrett, Vishal Sindhava, Isabel Sierra, Aimee Dubin, Michael Atchison, and Montserrat C. Anguera (2018). “Diversity of Epigenetic Features of the inactive X-chromosome in NK cells, dendritic cells, and macrophages”. Frontiers in Immunology. Dec 14. PMCID: PMC6331414.
- Sierra I, Anguera MC. (2019). “Enjoy the silence: X-chromosome inactivation diversity in somatic cells.” Curr Opin Genet Dev. 2019 Apr;55:26-31. Epub 2019 May 17. Review. PubMed PMID: 31108425; PubMed Central PMCID: PMC6759402.
4. Impact of autoimmune disease on X-Chromosome Inactivation mechanisms
We continue to investigate diseases exhibiting a female bias that also have abnormal increased expression of X-linked genes. My lab has focused on the autoimmune disorder systemic lupus erythematosus (SLE), which has a strong female-bias and exhibits aberrant over-expression of the X-linked genes CXCR3, CD40LG, TLR7, and FOXP3 in lymphocytes. We made the remarkable discovery that female SLE patients and mouse models with lupus-like disease have perturbations with markers of the inactive X, most notably XIST/Xist RNA localization and heterochromatic modifications H3K27me3 and H2AK119ubiquitin. Our work also found female-specific X-linked gene signatures of SLE patients. We are actively continuing this work in an effort to understand how transcription from the inactive X contributes to autoimmune disease susceptibility and disease severity, and also investigate mouse models of spontaneous lupus disease to examine how disease onset impacts XCI maintenance and X-linked gene expression.
- Syrett CM, Paneru B, Sandoval-Heglund D, Wang J, Banerjee S, Sindhava V, Behrens EM, Atchison M, & Anguera M.C. (2019) “Altered X-chromosome Inactivation in T cells may promote sex-biased autoimmune diseases”. JCI Insight, Apr 4;4(7). PMCID: PMC6483655.
- Syrett CM, Sierra I, Beethem ZT, Dubin AH, Anguera MC. “Loss of epigenetic modifications on the inactive X chromosome and sex-biased gene expression profiles in B cells from NZB/W F1 mice with lupus-like disease.” J Autoimmun. (2020) Feb;107:102357. Epub 2019 Nov 25. PubMed PMID: 31780316; PubMed Central PMCID: PMC7237307.
- Pyfrom S, Paneru B, Knoxx, J, Posso S, Buckner J, Cancro M, Anguera MC. “The dynamic epigenetic regulation of the inactive X chromosome in healthy human B cells is dysregulated in lupus patients”. Proc Natl Acad Sci. (2021) June;Vol.118.
- Jiwrajka N, Anguera MC. “The X in SeX-Biased Immunity and Autoimmune Rheumatic Disease.” J Exp Med. (2022). Review. doi 10.1084/jem.20211487.
Research Interest
My research program focuses on epigenetic gene regulation that underlies sex differences in development and disease. In particular, I am interested in understanding how gene expression from the X-chromosome is regulated to ensure dosage compensation between males and females, and how these mechanisms become altered in diseases exhibiting a sex-bias, such as autoimmunity. We investigate the female-specific epigenetic process of X-chromosome Inactivation (XCI). The X-chromosome contains genes necessary for cell proliferation, metabolism, cognition, reproduction, and has the highest density of immunity-related genes. Thus, gene expression from the X-chromosome is critical for cellular identity, and XCI ensures proper dosage of these genes in females. Abnormal expression of X-linked genes is a feature of many diseases exhibiting a sex-bias, including cancer, cardiovascular disease, and autoimmunity. I have a broad background in epigenetics, spanning the metabolism of one-carbon units that generate methyl groups that alter gene expression, to the epigenetic regulatory mechanisms involved in XCI. My independent research program at the University of Pennsylvania continues to investigate the epigenetic mechanisms that regulate X-linked gene expression, and how alterations result in female-biased disease. My laboratory has undertaken and completed studies establishing a new field of research, defining novel epigenetic pathways involving the X-chromosome that impact human development, immune responses during development, and lymphocyte function. We routinely use RNA and DNA fluorescence in situ hybridization, immunofluorescence experiment, and allele-specific RNA sequencing, which enables single-cell resolution of the epigenetic characteristics of the inactive X and transcriptional activity. Our long-term goal is to understand how dosage compensation of X-linked genes is maintained in lymphocytes, how perturbations with this silencing contribute to female-biased autoimmune disease, and how XCI maintenance mechanisms can be targeted to correct aberrant X-linked gene expression.
Ongoing Projects:
R01 AI134834
Anguera (PI)
6/01/2018-5/31/2023
Gene regulation from the inactive X in activated B cells
Lupus Mechanisms and Targets Award
Anguera (PI)
6/1/2020-5/30/2023
Targeting the inactive X for correcting dosage imbalances in lupus