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Zhang Y, Li X, Ba Z, Lou J, Gaertner KE, Zhu T, Lin X, Ye AY, Alt FW, Hu H. Molecular basis for differential Igk versus Igh V(D)J joining mechanisms. Nature 2024; 630:189-197. [PMID: 38811728 PMCID: PMC11153149 DOI: 10.1038/s41586-024-07477-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 04/26/2024] [Indexed: 05/31/2024]
Abstract
In developing B cells, V(D)J recombination assembles exons encoding IgH and Igκ variable regions from hundreds of gene segments clustered across Igh and Igk loci. V, D and J gene segments are flanked by conserved recombination signal sequences (RSSs) that target RAG endonuclease1. RAG orchestrates Igh V(D)J recombination upon capturing a JH-RSS within the JH-RSS-based recombination centre1-3 (RC). JH-RSS orientation programmes RAG to scan upstream D- and VH-containing chromatin that is presented in a linear manner by cohesin-mediated loop extrusion4-7. During Igh scanning, RAG robustly utilizes only D-RSSs or VH-RSSs in convergent (deletional) orientation with JH-RSSs4-7. However, for Vκ-to-Jκ joining, RAG utilizes Vκ-RSSs from deletional- and inversional-oriented clusters8, inconsistent with linear scanning2. Here we characterize the Vκ-to-Jκ joining mechanism. Igk undergoes robust primary and secondary rearrangements9,10, which confounds scanning assays. We therefore engineered cells to undergo only primary Vκ-to-Jκ rearrangements and found that RAG scanning from the primary Jκ-RC terminates just 8 kb upstream within the CTCF-site-based Sis element11. Whereas Sis and the Jκ-RC barely interacted with the Vκ locus, the CTCF-site-based Cer element12 4 kb upstream of Sis interacted with various loop extrusion impediments across the locus. Similar to VH locus inversion7, DJH inversion abrogated VH-to-DJH joining; yet Vκ locus or Jκ inversion allowed robust Vκ-to-Jκ joining. Together, these experiments implicated loop extrusion in bringing Vκ segments near Cer for short-range diffusion-mediated capture by RC-based RAG. To identify key mechanistic elements for diffusional V(D)J recombination in Igk versus Igh, we assayed Vκ-to-JH and D-to-Jκ rearrangements in hybrid Igh-Igk loci generated by targeted chromosomal translocations, and pinpointed remarkably strong Vκ and Jκ RSSs. Indeed, RSS replacements in hybrid or normal Igk and Igh loci confirmed the ability of Igk-RSSs to promote robust diffusional joining compared with Igh-RSSs. We propose that Igk evolved strong RSSs to mediate diffusional Vκ-to-Jκ joining, whereas Igh evolved weaker RSSs requisite for modulating VH joining by RAG-scanning impediments.
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Affiliation(s)
- Yiwen Zhang
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Xiang Li
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Zhaoqing Ba
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- National Institute of Biological Sciences, Beijing, China
| | - Jiangman Lou
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Copenhagen University, Copenhagen, Denmark
| | - K Elyse Gaertner
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Georgetown University, Washington, DC, USA
| | - Tammie Zhu
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Xin Lin
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Adam Yongxin Ye
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Frederick W Alt
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
| | - Hongli Hu
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
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Var SR, Strell P, Johnson ST, Roman A, Vasilakos Z, Low WC. Transplanting Microglia for Treating CNS Injuries and Neurological Diseases and Disorders, and Prospects for Generating Exogenic Microglia. Cell Transplant 2023; 32:9636897231171001. [PMID: 37254858 PMCID: PMC10236244 DOI: 10.1177/09636897231171001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/18/2023] [Accepted: 04/05/2023] [Indexed: 06/01/2023] Open
Abstract
Microglia are associated with a wide range of both neuroprotective and neuroinflammatory functions in the central nervous system (CNS) during development and throughout lifespan. Chronically activated and dysfunctional microglia are found in many diseases and disorders, such as Alzheimer's disease, Parkinson's disease, and CNS-related injuries, and can accelerate or worsen the condition. Transplantation studies designed to replace and supplement dysfunctional microglia with healthy microglia offer a promising strategy for addressing microglia-mediated neuroinflammation and pathologies. This review will cover microglial involvement in neurological diseases and disorders and CNS-related injuries, current microglial transplantation strategies, and different approaches and considerations for generating exogenic microglia.
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Affiliation(s)
- Susanna R. Var
- Department of Neurosurgery, Medical
School, University of Minnesota, Minneapolis, MN, USA
- Stem Cell Institute, Medical School,
University of Minnesota, Minneapolis, MN, USA
| | - Phoebe Strell
- Stem Cell Institute, Medical School,
University of Minnesota, Minneapolis, MN, USA
- Department of Veterinary and Biomedical
Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Sether T. Johnson
- Department of Neurosurgery, Medical
School, University of Minnesota, Minneapolis, MN, USA
- Stem Cell Institute, Medical School,
University of Minnesota, Minneapolis, MN, USA
| | - Alex Roman
- Department of Neuroscience, University
of Minnesota, Minneapolis, MN, USA
| | - Zoey Vasilakos
- Stem Cell Institute, Medical School,
University of Minnesota, Minneapolis, MN, USA
- Department of Neuroscience, University
of Minnesota, Minneapolis, MN, USA
| | - Walter C. Low
- Department of Neurosurgery, Medical
School, University of Minnesota, Minneapolis, MN, USA
- Stem Cell Institute, Medical School,
University of Minnesota, Minneapolis, MN, USA
- Department of Veterinary and Biomedical
Sciences, University of Minnesota, Minneapolis, MN, USA
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Dai HQ, Hu H, Lou J, Ye AY, Ba Z, Zhang X, Zhang Y, Zhao L, Yoon HS, Chapdelaine-Williams AM, Kyritsis N, Chen H, Johnson K, Lin S, Conte A, Casellas R, Lee CS, Alt FW. Loop extrusion mediates physiological Igh locus contraction for RAG scanning. Nature 2021; 590:338-343. [PMID: 33442057 PMCID: PMC9037962 DOI: 10.1038/s41586-020-03121-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/25/2020] [Indexed: 01/29/2023]
Abstract
RAG endonuclease initiates Igh V(D)J recombination in progenitor B cells by binding a JH-recombination signal sequence (RSS) within a recombination centre (RC) and then linearly scanning upstream chromatin, presented by loop extrusion mediated by cohesin, for convergent D-RSSs1,2. The utilization of convergently oriented RSSs and cryptic RSSs is intrinsic to long-range RAG scanning3. Scanning of RAG from the DJH-RC-RSS to upstream convergent VH-RSSs is impeded by D-proximal CTCF-binding elements (CBEs)2-5. Primary progenitor B cells undergo a mechanistically undefined contraction of the VH locus that is proposed to provide distal VHs access to the DJH-RC6-9. Here we report that an inversion of the entire 2.4-Mb VH locus in mouse primary progenitor B cells abrogates rearrangement of both VH-RSSs and normally convergent cryptic RSSs, even though locus contraction still occurs. In addition, this inversion activated both the utilization of cryptic VH-RSSs that are normally in opposite orientation and RAG scanning beyond the VH locus through several convergent CBE domains to the telomere. Together, these findings imply that broad deregulation of CBE impediments in primary progenitor B cells promotes RAG scanning of the VH locus mediated by loop extrusion. We further found that the expression of wings apart-like protein homologue (WAPL)10, a cohesin-unloading factor, was low in primary progenitor B cells compared with v-Abl-transformed progenitor B cell lines that lacked contraction and RAG scanning of the VH locus. Correspondingly, depletion of WAPL in v-Abl-transformed lines activated both processes, further implicating loop extrusion in the locus contraction mechanism.
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Affiliation(s)
- Hai-Qiang Dai
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.,Correspondence: ; ; . Correspondence and requests for materials should be addressed to F.W.A
| | - Hongli Hu
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Jiangman Lou
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Adam Yongxin Ye
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Zhaoqing Ba
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Xuefei Zhang
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Yiwen Zhang
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Lijuan Zhao
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Hye Suk Yoon
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Aimee M. Chapdelaine-Williams
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Nia Kyritsis
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Huan Chen
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Kerstin Johnson
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Sherry Lin
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Andrea Conte
- Lymphocyte Nuclear Biology, NIAMS, NIH, and Center of Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
| | - Rafael Casellas
- Lymphocyte Nuclear Biology, NIAMS, NIH, and Center of Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
| | - Cheng-Sheng Lee
- Institute of Molecular and Cellular Biology, Department of Life Sciences, Hsinchu, Taiwan, 30013, R.O.C.,Correspondence: ; ; . Correspondence and requests for materials should be addressed to F.W.A
| | - Frederick W. Alt
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.,Correspondence: ; ; . Correspondence and requests for materials should be addressed to F.W.A
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Posabella A, Alber AB, Undeutsch HJ, Droeser RA, Hollenberg AN, Ikonomou L, Kotton DN. Derivation of Thyroid Follicular Cells From Pluripotent Stem Cells: Insights From Development and Implications for Regenerative Medicine. Front Endocrinol (Lausanne) 2021; 12:666565. [PMID: 33959101 PMCID: PMC8095374 DOI: 10.3389/fendo.2021.666565] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/29/2021] [Indexed: 11/13/2022] Open
Abstract
Stem cell-based therapies to reconstitute in vivo organ function hold great promise for future clinical applications to a variety of diseases. Hypothyroidism resulting from congenital lack of functional thyrocytes, surgical tissue removal, or gland ablation, represents a particularly attractive endocrine disease target that may be conceivably cured by transplantation of long-lived functional thyroid progenitors or mature follicular epithelial cells, provided a source of autologous cells can be generated and a variety of technical and biological challenges can be surmounted. Here we review the emerging literature indicating that thyroid follicular epithelial cells can now be engineered in vitro from the pluripotent stem cells (PSCs) of mice, normal humans, or patients with congenital hypothyroidism. We review the in vivo embryonic development of the thyroid gland and explain how emerging discoveries in developmental biology have been utilized as a roadmap for driving PSCs, which resemble cells of the early embryo, into mature functional thyroid follicles in vitro. Finally, we discuss the bioengineering, biological, and clinical hurdles that now need to be addressed if the goals of life-long cure of hypothyroidism through cell- and/or gene-based therapies are to be attained.
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Affiliation(s)
- Alberto Posabella
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, MA, United States
- University Center of Gastrointestinal and Liver Diseases—Clarunis, University of Basel, Basel, Switzerland
| | - Andrea B. Alber
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, MA, United States
| | - Hendrik J. Undeutsch
- Division of Endocrinology, Diabetes and Metabolism, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medicine, New York, NY, United States
| | - Raoul A. Droeser
- University Center of Gastrointestinal and Liver Diseases—Clarunis, University of Basel, Basel, Switzerland
| | - Anthony N. Hollenberg
- Division of Endocrinology, Diabetes and Metabolism, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medicine, New York, NY, United States
| | - Laertis Ikonomou
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, MA, United States
- The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA, United States
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, State University of New York, Buffalo, NY, United States
| | - Darrell N. Kotton
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, MA, United States
- The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA, United States
- *Correspondence: Darrell N. Kotton,
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