Kristen Kroll is an American developmental and stem cell biologist and Professor of Developmental Biology at Washington University School of Medicine. Her laboratory studies transcriptional and epigenetic regulation of brain development and its disruption to cause neurodevelopmental disorders.[2][3][4]
Early life and education
Kroll grew up in Wisconsin. She graduated from Wilmot High School in 1984 and received her Bachelor's Degree with the highest honors from Northwestern University in 1988.[5][6][7] She became interested in a career in developmental biology while doing undergraduate research in the laboratory of Robert Holmgren, where her project involved cloning the segment polarity gene Cubitus interruptus, a Drosophila homolog of the GLI transcription factors that mediate Hedgehog signaling.[5]
As a Damon Runyon-Walter Winchell Foundation Postdoctoral Fellow, Kroll pursued an interest in developmental biology during postdoctoral work in Marc Kirschner's lab at Harvard Medical School.[5][15] She used functional screening of cDNA libraries to define novel regulators of early embryonic development. These included Geminin (Gmnn), a novel nuclear protein that she identified based on its ability to expand the Xenopusneural plate at the expense of non-neural tissue.[5][16]
Kroll joined the Department of Developmental Biology (previously Dept. of Molecular Biology and Pharmacology) at Washington University School of Medicine in 2000. Her laboratory has focused on identifying how transcriptional and epigenetic regulation controls various aspects of neural development.[2][3]
Research areas
A major focus of work in the Kroll laboratory has been to identify mechanisms underlying transcriptional and epigenetic control of embryonic development.[17][18][19][20][21][22][23][24] They demonstrated that Gmnn plays an essential role in these processes, showing that Gmnn is required for neural fate acquisition of embryonic stem cells and promotes an accessible and hyperacetylated chromatin state that facilitates neural gene transcription[19] while also limiting non-neural fate acquisition (endoderm/mesoderm) through functional cooperativity with Polycomb complex (PcG)-mediated epigenetic repression.[18][20] They demonstrated that Gmnn associates with and promotes histone acetylation at regulatory elements of many neurodevelopmental genes and used these data to construct gene regulatory networks underlying neural fate acquisition.[5][17][19]
Beyond early cell fate acquisition, they also defined other aspects of development that require Gmnn, including regulating gene expression during neurogenesis, neuronal differentiation, and neural tube patterning and controlling Hox gene regulation to pattern the vertebrate limb, and they also demonstrated that Gmnn deficiency enhanced survival and response to therapy in mouse models of the pediatric brain tumor medulloblastoma.[25][26] This body of work established Gmnn as a key cell-intrinsic regulator of several aspects of embryogenesis through its interactions with the SWI/SNF and Polycomb chromatin-modifying complexes.[5][23][27][28][29][30]
Current work in the Kroll laboratory uses directed differentiation of human pluripotent stem cells to identify regulatory networks controlling the development of human neuronal cell types that are frequently disrupted in neurodevelopmental disorders. These include cortical interneurons (cINs), GABAergic inhibitory neurons that modulate excitatory neuronal activity in the cortex by providing local inhibition. The laboratory developed modified protocols for directed differentiation of human pluripotent stem cells (hPSCs) efficiently into cINs that provide an effective model for elucidating mechanisms of human cIN development. They have subsequently used this model to define regulatory networks that control human cIN development.[31][32][33]
As of 2021, Kroll leads efforts to characterize how pathogenic gene variants contribute to intellectual and developmental disabilities (IDDs) in hPSC-derived models at Washington University School of Medicine (WUSM). She leads the Cellular Models program for WUSM's Intellectual and Developmental Disabilities Research Center (IDDRC), coordinating with the IDDRC's Clinical-Translational Core to build patient-derived cellular models of IDDs.[citation needed] She coordinates human cell and organoid-based modeling under WUSM's Precision Medicine Integrated Experimental Resources (PreMIER) platform, WU's model organism screening platform for precision medicine. She also co-leads the NICHD-supported Cross-IDDRC Human Cellular Models Group, which engages the 14 IDDRCs in the United States in collaborative efforts to build and share human IDD cellular models, develop cross-IDDRC calibrated platforms for human cellular modeling, perform data meta-analyses, and develop IDD model bio- and data-repositories models as resources for the network.[34]
Awards
Kroll has received several awards for her work, including the March of DimesBasil O’Connor Award, the American Cancer Society Research Scholar grant, and American Cancer Society Hope Award.[35] Her other awards include:
National Institutes of Health Study Sections and Special Emphasis Panels: Permanent member Developmental Biology 2 (DEV2) NIH Study Section (2014-2020); Ad hoc Member: Molecular, Cellular, and Developmental Neuroscience (MDCN) study section, Neurogenetics and Genomics Special Emphasis and Challenge Grants Panels, Neurogenesis and Cell Fate (NCF) Study Sections, Genomic and Genetic Analysis in Xenopus Special Emphasis Panels[citation needed]
Co-chair, Cross-Intellectual, and Developmental Disabilities Research Center (IDDRC) Human Stem Cell Models Group (2018-present)[citation needed]
Co-Director, Instructor, or Lecturer, Cold Spring Harbor Laboratory Cell and Developmental Biology of Xenopus laevis Course (1996-1999, 2001, 2003, 2005, 2008-2010)[citation needed]
Personal life
Kroll is married to John D. Bradley, a scientist at Bayer.[37][38] Her sister, Jennifer Lee Kroll, died on May 9, 2020, at 52 years of age, due to metastatic breast cancer. She was writer who published more than 30 books.[39][40] Kroll is also the granddaughter of Josephine LeGrave Wautlet, author of several works, including a language course called Phonetic Walloon for Belgian Americans.[2][3] Her grandmother was also featured in an oral history on Belgian Americans and the Walloon language (University of Wisconsin, Green Bay).[41]
Selected publications
Kristen Kroll has more than 50 publications in the field of developmental biology including:
Kroll, K.L.; Amaya, E. (1996-10-01). "Transgenic Xenopus embryos from sperm nuclear transplantations reveal FGF signaling requirements during gastrulation". Development. 122 (10). The Company of Biologists: 3173–3183. doi:10.1242/dev.122.10.3173. ISSN1477-9129. PMID8898230. S2CID20349983.
Kroll, K.L.; Salic, A.N.; Evans, L.M.; Kirschner, M.W. (1998-08-15). "Geminin, a neuralizing molecule that demarcates the future neural plate at the onset of gastrulation". Development. 125 (16). The Company of Biologists: 3247–3258. doi:10.1242/dev.125.16.3247. ISSN1477-9129. PMID9671596.
Lustig, K.D.; Kroll, K.L.; Sun, E.E.; Kirschner, M.W. (1996-12-01). "Expression cloning of a Xenopus T-related gene (Xombi) involved in mesodermal patterning and blastopore lip formation". Development. 122 (12). The Company of Biologists: 4001–4012. doi:10.1242/dev.122.12.4001. ISSN1477-9129. PMID9012520.
Seo, Seongjin; Richardson, Genova A.; Kroll, Kristen L. (2005-01-01). "The SWI/SNF chromatin remodeling protein Brg1 is required for vertebrate neurogenesis and mediates transactivation of Ngn and NeuroD". Development. 132 (1). The Company of Biologists: 105–115. doi:10.1242/dev.01548. ISSN1477-9129. PMID15576411. S2CID6987785.
Salic, A.N.; Kroll, K.L.; Evans, L.M.; Kirschner, M.W. (1997-12-01). "Sizzled: a secreted Xwnt8 antagonist expressed in the ventral marginal zone of Xenopus embryos". Development. 124 (23). The Company of Biologists: 4739–4748. doi:10.1242/dev.124.23.4739. ISSN1477-9129. PMID9428410.
^Kroll KL, Salic AN, Evans LM, Kirschner MW (August 1998). "Geminin, a neuralizing molecule that demarcates the future neural plate at the onset of gastrulation". Development. 125 (16): 3247–58. doi:10.1242/dev.125.16.3247. PMID9671596.
^Seo S, Richardson GA, Kroll KL (January 2005). "The SWI/SNF chromatin remodeling protein Brg1 is required for vertebrate neurogenesis and mediates transactivation of Ngn and NeuroD". Development. 132 (1): 105–15. doi:10.1242/dev.01548. PMID15576411. S2CID6987785.
^Kaeser MD, Emerson BM (October 2006). "Remodeling plans for cellular specialization: unique styles for every room". Curr Opin Genet Dev. 16 (5): 508–12. doi:10.1016/j.gde.2006.08.001. PMID16905306.
^de la Serna IL, Ohkawa Y, Imbalzano AN (June 2006). "Chromatin remodelling in mammalian differentiation: lessons from ATP-dependent remodellers". Nat Rev Genet. 7 (6): 461–73. doi:10.1038/nrg1882. PMID16708073. S2CID24086145.