Nancy R Manley

University of Georgia | UGA · Department of Genetics

Thymic epithelial cells (TECs) are essential for T cell development in the thymus, yet the mechanisms governing their differentiation are not well understood. Lin28, known for its roles in embryonic development, stem cell pluripotency, and regulating cell proliferation and differentiation, is expressed in endodermal epithelial cells during embryoge...

The transcription factor FOXN1 is essential for fetal thymic epithelial cell (TEC) differentiation and proliferation. Postnatally, Foxn1 levels vary widely between TEC subsets, from low/undetectable in putative TEC progenitors to highest in differentiated TEC subsets. Correct Foxn1 expression is required to maintain the postnatal microenvironment;...

The generation of a functional, self-tolerant T cell receptor (TCR) repertoire depends on interactions between developing thymocytes and antigen-presenting thymic epithelial cells (TECs). Cortical TECs (cTECs) rely on unique antigen-processing machinery to generate self-peptides specialized for T cell positive selection. In our current study, we fo...

Background: Localized and total body irradiation are used to treat certain cancers and also used prior to the transplantation of stem cells or organs. However, the use of radiation also induces collateral damage to the cells of healthy tissue. Although the acute damage of radiation to oocytes is well known, the long-term effects induced by radiatio...

The cortical and medullary thymic epithelial cell (cTEC and mTEC) lineages are essential for inducing T cell lineage commitment, T cell positive selection and the establishment of self-tolerance, but the mechanisms controlling their fetal specification and differentiation are poorly understood. Here, we show that Notch signaling is required to spec...

Abstract Thymic epithelial cells (TEC) are essential for thymocyte differentiation and repertoire selection. Despite their indispensable role in generating functional T cells, the molecular mechanisms that orchestrate TEC development from endodermal progenitors in the third pharyngeal pouch (3rd PP) are not fully understood. We recently reported th...

The postnatal thymus is an efficient microenvironment for T cell specification and differentiation. B cells are also present in the thymus and have been recently shown to impact T cell selection, however, the mechanisms controlling B cell development in the thymus are largely unknown. In Foxn1lacZ mutant mice, down-regulation of Foxn1 expression in...

Background Hematopoietic stem cells (HSCs) derived from birth through adult possess differing differentiation potential for T or B cell fate in the thymus; neonatal bone marrow (BM) cells also have a higher potential for B cell production in BM compared to adult HSCs. We hypothesized that this hematopoietic-intrinsic B potential might also regulate...

Comparison of thymic B cells in Wt and +/Z mice. BL6 Wt mice were crossed with +/Z mice to generate Wt and +/Z mice. Total thymocytes were analyzed at age of 6–9 weeks. (A). Total thymocytes from Wt and +/Z mice were gated on DN cells (left panels), and then gated on the DN1 subset (middle panel), the thymic B cells profiles of CD19 and B220 were s...

NC3Rs ARRIVE guidelines checklist thyB2.pdf. (PDF)

Flow cytometry analysis of thymic B cells after BM cells transfer. (A-B). 3000 LSK cells sorted from day 14 BM of CD45.1 mice were retro-orbital transferred into the sub-irradiated 42-day Z/N mice (A), similarly, 3-month LSKs were transferred into 17-day Z/N mice (B) respectively. The profile of CD19 and CD24 staining were showed in donor and host....

The cell sorting of BM pre-B cells from BM and thymus. (A-B). The total BM cells (A) and total thymocytes (B) from CD45.1 were stained by B220, CD19, CD24, CD43 and IgM + Lin, and the progenitor B cells were sorted on B220+CD19+ CD24+CD43+/loIgM-Lin- subpopulation by MoFloTM cell sorter. (TIF)

NC3Rs ARRIVE guidelines checklist. (PDF)

The thymus is not only extremely sensitive to damage but also has a remarkable ability to repair itself. However, the mechanisms underlying this endogenous regeneration remain poorly understood, and this capacity diminishes considerably with age. We show that thymic endothelial cells (ECs) comprise a critical pathway of regeneration via their produ...

Total body irradiation (TBI) damages hematopoietic cells in the bone marrow and thymus; however, the long-term effects of irradiation with aging remain unclear. In this study, we found that the impact of radiation on thymopoiesis in mice varied by sex and dose but, overall, thymopoiesis remained suppressed for ≥12 mo after a single exposure. Male a...

The thymus and parathyroids develop from shared organ primordia derived from third pharyngeal pouch (3(rd) pp) endoderm. Our previous studies show that Sonic hedgehog (Shh) null mutants have smaller, aparathyroid primordia in which thymus fate specification extends into the pharynx. SHH signaling is active in both dorsal pouch endoderm and neighbor...

Hoxa3null mice have severe defects in the development of pharyngeal organs including athymia, aparathyroidism, thyroid hypoplasia, and ultimobranchial body persistence, in addition to defects of the throat cartilages and cranial nerves. Some of the structures altered in the Hoxa3null mutant embryos are anterior to the described Hoxa3 gene expressio...

Endogenous thymic regeneration is a crucial function that allows for renewal of immune competence following immunodepletion caused by cytoreductive chemotherapy or radiation; however, the mechanisms governing this regeneration remain poorly understood. Moreover, despite this capacity, prolonged T cell deficiency is a major clinical hurdle in recipi...

The experimental manipulation of mid-gestation mouse embryos is an important tool for the study of developmental biology. However, such techniques can be challenging due to difficulties accessing the embryos in utero, and therefore the ability to maintain mid-gestation mouse embryos in vitro has proved invaluable. Described here is an example of a...

The thoracic thymus is the primary vertebrate organ for T-cell generation. Accessory cervical thymi have also been identified in humans and mice, and shown in mice to be independent functional organs that support T-cell development. However, their origin and functional significance remain unclear. Here we show that cervical thymi in mice have follo...

The thymus is composed of multiple stromal elements comprising specialized stromal microenvironments responsible for the development of self-tolerant and self-restricted T cells. Here, we investigated the ontogeny and maturation of the thymic vasculature. We show that endothelial cells initially enter the thymus at E13.5, with PDGFR-β(+) mesenchyma...

EpCAM and CD45 expression in depleted stroma from Foxn1Δ/Δ thymus. (A) EpCAM expression is normal in pooled E13.5 Foxn1Δ/Δ and control thymi before and after CD45+ cell depletion. (B) CD45 expression before and after CD45+ cell depletion in pooled E13.5 Foxn1Δ/Δ and control thymi. (TIF)

Initial thymic vascularization is similar in E13.5 Foxn1+/+ and Foxn1+/Δ mice. Immunofluorescence analysis of CD144 (VE-Cadherin) and Keratin 5 (K5) in the wild-type thymus from frozen sections of whole embryos (E12.5, E13.5) and dissected thymi (E15.5, E17.5). Timing of vascularization of overall vessel patterning is similar to that seen in Foxn1+...

Collagen IV is broadly expressed throughout NB Foxn1Δ/Δ thymus. Immunofluorescence analysis of embryonic (A–F) and newborn transverse sections (G–H) of thymus for CD31+ (blue) and Collagen IV (green). Collagen IV deposits adjacent to CD31+ cells in E12.5 (A) Foxn1+/Δ and (B) Foxn1Δ/Δ, E13.5 (C) Foxn1+/Δ and (D) Foxn1Δ/Δ, E15.5 (E) Foxn1+/Δ and (F)...

Thymic involution during aging is a major cause of decreased production of T cells and reduced immunity. Here we show that inactivation of Rb family genes in young mice prevents thymic involution and results in an enlarged thymus competent for increased production of naive T cells. This phenotype originates from the expansion of functional thymic e...

835 The establishment of the thymic microenvironment early in life is crucial for the production functional T cells. Conversely, thymic involution results in a decreased T cell output. Thymic involution has important health implications especially following bone marrow transplant. Our objective is to determine molecular and cellular mechanisms that...

The thymus and parathyroid glands are derived from the third pharyngeal pouch endoderm. The mechanisms that establish distinct molecular domains in the third pouch and control the subsequent separation of these organ primordia from the pharynx are poorly understood. Here, we report that mouse embryos that lack two FGF feedback antagonists, Spry1 an...

Aging is associated with decreased immune function that leads to increased morbidity and mortality in the elderly. Immune senescence is accompanied by age-related changes in two primary lymphoid organs, bone marrow and thymus, that result in decreased production and function of B and T lymphocytes. In bone marrow, hematopoietic stem cells exhibit r...

The establishment of a functional blood vessel network is an essential part of organogenesis, and is required for optimal organ function. For example, in the thymus proper vasculature formation and patterning is essential for thymocyte entry into the organ and mature T-cell exit to the periphery. The spatial arrangement of blood vessels in the thym...

Whole mount in situ hybridization is a very informative approach for defining gene expression patterns in embryos. The in situ hybridization procedures are lengthy and technically demanding with multiple important steps that collectively contribute to the quality of the final result. This protocol describes in detail several key quality control ste...

The thymus is the primary organ responsible for generating functional T cells in vertebrates. Although T cell differentiation within the thymus has been an area of intense investigation, the study of thymus organogenesis has made slower progress. The past decade, however, has seen a renewed interest in thymus organogenesis, with the aim of understa...

Organs are more than the sum of their component parts--functional competence requires that these parts not only be present in the appropriate proportions, but also be arranged and function together in specific ways. The thymus is an excellent example of the connection between cellular organization and organ function. Unlike more familiar organs, su...

Transcriptional regulatory networks are the central regulatory mechanisms that control organ identity, patterning, and differentiation. In the case of the thymus, several key transcription factors have been identified that are critical for various aspects of thymus organogenesis and thymic epithelial cell (TEC) differentiation. The thymus forms fro...

In mammals, parathyroid hormone (PTH) is a key regulator of extracellular calcium and inorganic phosphorus homeostasis. Although the parathyroid glands were thought to be the only source of PTH, extra-parathyroid PTH production in the thymus, which shares a common origin with parathyroids during organogenesis, has been proposed to provide an auxili...

Foxn1(Δ/Δ) mutant mice have a specific defect in thymic development, characterized by a block in TEC differentiation at an intermediate progenitor stage, and blocks in thymocyte development at both the DN1 and DP cell stages, resulting in the production of abnormally functioning T cells that develop from an atypical progenitor population. In the cu...

Thymus organogenesis requires coordinated interactions of multiple cell types, including neural crest (NC) cells, to orchestrate the formation, separation, and subsequent migration of the developing thymus from the third pharyngeal pouch to the thoracic cavity. The molecular mechanisms driving these processes are unclear; however, NC-derived mesenc...

Heterozygous mutations of GATA3, which encodes a dual zinc-finger transcription factor, cause hypoparathyroidism with sensorineural deafness and renal dysplasia. Here, we have investigated the role of GATA3 in parathyroid function by challenging Gata3+/- mice with a diet low in calcium and vitamin D so as to expose any defects in parathyroid functi...

Hox genes play evolutionarily conserved roles in specifying axial position during embryogenesis. A prevailing paradigm is that changes in Hox gene expression drive evolution of metazoan body plans. Conservation of Hox function across species, and among paralogous Hox genes within a species, supports a model of functional equivalence. In this report...

Vishwa Deep Dixit, Yun-Hee Youm, Hyunwon Yang, Christo Venkov, Nancy R Manley, Eric Nielson, Todd Leff, Bolormaa Vandanmagsar By 50 years of age most of human thymus is replaced with adipocytes of unknown provenance and uncertain function. We investigated the lineage and mechanism of thymic adipocyte formation during aging and asked whether manipul...

The thymus and parathyroids are pharyngeal endoderm-derived organs that develop from common organ primordia, which undergo a series of morphological events resulting in separate organs in distinct locations in the embryo. Previous gene expression and functional analyses have suggested a role for BMP4 signaling in early thymus organogenesis. We have...

Transformation of epithelial cells is associated with loss of cell polarity, which includes alterations in cell morphology as well as changes in the complement of plasma membrane proteins. Rab proteins regulate polarized trafficking to the cell membrane and therefore represent potential regulators of this neoplastic transition. Here we have demonst...

There is an accumulating body of evidence that a decline in immune function with age is common to most if not all vertebrates. For instance, age-associated thymic involution seems to occur in all species that possess a thymus, indicating that this process is evolutionary ancient and conserved. The precise mechanisms regulating immunosenescence rema...

Development of a functional thymic microenvironment depends on crosstalk between multiple cell types. Recent studies suggest that crosstalk between developing vasculature and thymic epithelial cells (TEC) actively contributes to the complex thymic architecture, but little is known about initial immigration of endothelial precursor cells (EPC) into...

With progressive aging, adipocytes are the major cell types that constitute the bulk of thymic microenvironment. Understanding the origin of thymic adipocytes and mechanisms responsible for age-related thymic adiposity is thus germane for the design of long lasting thymic rejuvenation strategies. We have recently identified that ghrelin, an orexige...

Embryos that are homozygous for Splotch, a null allele of Pax3, have a severe neural crest cell (NCC) deficiency that generates a complex phenotype including spina bifida, exencephaly and cardiac outflow tract abnormalities. Contrary to the widely held perception that thymus aplasia or hypoplasia is a characteristic feature of Pax3(Sp/Sp) embryos,...

Vertebrate dentitions originated in the posterior pharynx of jawless fishes more than half a billion years ago. As gnathostomes (jawed vertebrates) evolved, teeth developed on oral jaws and helped to establish the dominance of this lineage on land and in the sea. The advent of oral jaws was facilitated, in part, by absence of hox gene expression in...

Referenced Molecular Interactions during Tooth Development from the Interactions Schematized in Figure 7, Panel 4. (80 KB DOC)

Mean Oral and Pharyngeal Tooth Counts and Standard Length (SL) for One to Four Malawi Cichlid Adults from 37 Species D. compressiceps, M. zebra, and L. fuelleborni (asterisks) are indicated on Figure 2A–2K. (30 KB DOC)

The postnatal thymus is the primary source of T cells in vertebrates, and many if not all stages of thymocyte development require interactions with thymic epithelial cells (TECs). The Foxn1 gene is a key regulator of TEC differentiation, and is required for multiple aspects of fetal TEC differentiation. Foxn1 is also expressed in the postnatal thym...

Koch et al. 2008. J. Exp. Med. doi:10.1084/jem.20080829[OpenUrl][1][Abstract/FREE Full Text][2] [1]: {openurl}?query=rft.jtitle%253DJ.%2BExp.%2BMed.%26rft_id%253Dinfo%253Adoi%252F10.1084%252Fjem.20080829%26rft_id%253Dinfo%253Apmid%252F18824585%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi

Thymic T cell lineage commitment is dependent on Notch1 (N1) receptor-mediated signaling. Although the physiological ligands that interact with N1 expressed on thymic precursors are currently unknown, in vitro culture systems point to Delta-like 1 (DL1) and DL4 as prime candidates. Using DL1- and DL4-lacZ reporter knock-in mice and novel monoclonal...

Tracheal agenesis/atresia (TA) is a rare but fatal congenital disease in which the breathing tube fails to grow. The etiology of this serious condition remains largely unknown. We found that Bmp signaling is prominently present in the anterior foregut where the tracheal primordium originates and targeted ablation of Bmp4 (Bmp4(cko)) resulted in a l...

Foxn1Delta is a hypomorphic allele of the nude gene that causes arrested thymic epithelial cell differentiation and abnormal thymic architecture lacking cortical and medullary domains. T cells develop in the Foxn1Delta/Delta adult thymus to the double- and single-positive stages, but in the apparent absence of double-negative 3 (DN3) cells; however...

Foxn1Delta/Delta mutants have a block in thymic epithelial cell differentiation at an intermediate progenitor stage, resulting in reduced thymocyte cellularity and blocks at the double-negative and double-positive stages. Whereas naive single-positive thymocytes were reduced >500-fold in the adult Foxn1Delta/Delta thymus, peripheral T cell numbers...

The parathyroid glands develop with the thymus from bilateral common primordia that develop from the 3rd pharyngeal pouch endoderm in mouse embryos at about E11, each of which separates into one parathyroid gland and one thymus lobe by E13.5. Gcm2, a mouse ortholog of the Drosophila Glial Cells Missing gene, is expressed in the parathyroid-specific...

Foxp3 is essential for the commitment of differentiating thymocytes to the regulatory CD4(+) T (T reg) cell lineage. In humans and mice with a genetic Foxp3 deficiency, absence of this critical T reg cell population was suggested to be responsible for the severe autoimmune lesions. Recently, it has been proposed that in addition to T reg cells, Fox...

Thymic epithelial cells (TECs) promote thymocyte maturation and are required for the early stages of thymocyte development and for positive selection. However, investigation of the mechanisms by which TECs perform these functions has been inhibited by the lack of genetic tools. Since the Foxn1 gene is expressed in all presumptive TECs from the earl...

Thymus seeding by T-lymphoid progenitor cells is a prerequisite for T-cell development. However, molecules guiding thymus colonization and their roles before and after thymus vascularization are unclear. Here we show that mice doubly deficient for chemokine receptors CCR7 and CCR9 were defective specifically in fetal thymus colonization before, but...

The thymus and parathyroids originate from the third pharyngeal pouches, which form as endodermal outpocketings in the pharyngeal region beginning on embryonic day 9 (E9.0) of mouse development. Using organ-specific markers, we have previously shown that thymus and parathyroid-specific organ domains are established within the primordium prior to fo...

Previous studies have implicated Sonic hedgehog (Shh) as an important regulator of pharyngeal region development. Here we show that Shh is differentially expressed within the pharyngeal endoderm along the anterior-posterior axis. In Shh-/- mutants, the pharyngeal pouches and arches formed by E9.5 and marker expression showed that initial patterning...