Medullary Epithelium Research Articles

Optimization of the Flavonoid Extraction Process from the Stem and Leaves of Epimedium Brevicornum and Its Effects on Cyclophosphamide-Induced Renal Injury.

Cyclophosphamide (CTX) is a broad-spectrum alkylated antitumor drug. It is clinically used in the treatment of a variety of cancers, and renal toxicity is one of the adverse reactions after long-term or repeated use, which not only limits the therapeutic effect of CTX, but also increases the probability of kidney lesions. The total flavonoids of Epimedium stem and leaf (EBF) and Icariin (ICA) are the main medicinal components of Epimedium, and ICA is one of the main active substances in EBF. Modern pharmacological studies have shown that EBF has a variety of biological activities such as improving osteoporosis, promoting cell proliferation, antioxidant and anti-inflammatory properties, etc. However, few studies have been conducted on the nephrotoxicity caused by optimized CTX extraction, and protein-ligand binding has not been involved. This research, through the response surface optimization extraction of EBF, obtained the best extraction conditions: ethanol concentration was 60%, solid-liquid ratio of 25:1, ultrasonic time was about 25 min. Combined with mass spectrometry (MS) analysis, EBF contained ICA, ichopidin A, ichopidin B, ichopidin C, and other components. In this study, we adopted a computational chemistry method called molecular docking, and the results show that Icariin was well bound to the antioxidant target proteins KEAP1 and NRF2, and the anti-inflammatory target proteins COX-2 and NF-κB, with free binding energies of -9.8 kcal/mol, -11.0 kcal/mol, -10.0 kcal/mol, and -8.1 kcal/mol, respectively. To study the protective effect of EBF on the nephrotoxicity of CTX, 40 male Kunming mice (weight 18 ± 22) were injected with CTX (80 mg/kg) for 7 days to establish the nephrotoxicity model and were treated with EBF (50 mg/kg, 100 mg/kg) for 8 days by gavage. After CTX administration, MDA, BUN, Cre, and IL-6 levels in serum increased, MDA increased in kidney, GPT/ALT and IL-6 increased in liver, and IL-6 increased in spleen and was significant ((p < 0.05 or (p < 0.01)). Histopathological observation showed that renal cortex glomerular atrophy necrosis, medullary inflammatory cell infiltration, and other lesions. After administration of EBF, CTX-induced increase in serum level of related indexes was reduced, and MDA in kidney, GPT/ALT and IL-6 in liver, and IL-6 in spleen were increased. At the same time, histopathological findings showed that the necrosis of medullary and corticorenal tubular epithelium was relieved at EBF (50 mg/kg) dose compared with the CTX group, and the glomerular tubular necrosis gradually became normal at EBF (100 mg/kg) dose. Western blot analysis of Keap1 and Nrf2 protein expression in kidney tissue showed that compared with model CTX group, the drug administration group could alleviate the high expression of Keap1 protein and low expression of Nrf2 protein in kidney tissue. Conclusion: After the optimal extraction of total flavonoids from the stems and leaves of Epimedium, the molecular docking technique combined with animal experiments suggested that the effective component of the total flavonoids of Epimedium might activate the Keap1-Nrf2 signaling pathway after treatment to reduce the inflammation and oxidative stress of kidney tissue, so as to reduce kidney damage and improve kidney function. Therefore, EBF may become a new natural protective agent for CTX chemotherapy in the future.

Incidental detection of teratoid benign medulloepithelioma of cilliary body of eye- A rare case report &amp; literature review

Intraocular medulloepithelioma of cilliary body is a nonhereditary neoplasm of childhood arising from primitive medullary epithelium characterized by cords of multi-layered neuroepithelial cells resembling medullary epithelium of the optic cup. It often present as loss of vision, painful eye &amp; leucocoria. Common signs include secondary glaucoma &amp; dislocated lens. About half of patients undergo surgery before discovery of this tumor. We report a case of cilliary body teratoid benign meduloepithelioma in a 4 year female child, presented as phthisical eye, detected incidentally &amp; relevant literature.

Minimal Kidney Disease Phenotype in Shroom3 Heterozygous Null Mice.

Shroom family member 3 (SHROOM3) encodes an actin-associated protein that regulates epithelial morphology during development. Several genome-wide association studies (GWAS) have identified genetic variances primarily in the 5' region of SHROOM3, associated with chronic kidney disease (CKD) and poor transplant outcomes. These genetic variants are associated with alterations in Shroom3 expression. Characterize the phenotypic abnormalities associated with reduced Shroom3 expression in postnatal day 3-, 1-month and 3-month-old mice. The Shroom3 protein expression pattern was determined by immunofluorescence. We generated Shroom3 heterozygous null mice (Shroom3Gt/+) and performed comparative analyses with wild type littermates based on somatic and kidney growth, gross renal anatomy, renal histology, renal function at postnatal day 3, 1 month, and 3 months. The Shroom3 protein expression localized to the apical regions of medullary and cortical tubular epithelium in postnatal wild type kidneys. Co-immunofluorescence studies confirmed protein expression localized to the apical side of the tubular epithelium in proximal convoluted tubules, distal convoluted tubules, and collecting ducts. While Shroom3 heterozygous null mice exhibited reduced Shroom3 protein expression, no differences in somatic and kidney growth were observed when compared to wild type mice. Although, rare cases of unilateral hypoplasia of the right kidney were observed at postnatal 1 month in Shroom3 heterozygotes. Yet renal histological analysis did not reveal any overt abnormalities in overall kidney structure or in glomerular and tubular organization in Shroom3 heterozygous null mice when compared to wild type mice. Analysis of the apical-basolateral orientation of the tubule epithelium demonstrated alterations in the proximal convoluted tubules and modest disorganization in the distal convoluted tubules at 3 months in Shroom3 heterozygotes. Additionally, these modest abnormalities were not accompanied by tubular injury or physiological defects in renal and cardiovascular function. Taken together, our results describe a mild kidney disease phenotype in adult Shroom3 heterozygous null mice, suggesting that Shroom3 expression and function may be required for proper structure and maintenance of the various tubular epithelial parenchyma of the kidney.

Insulinoma-associated-1 (INSM1) expression in thymic squamous cell carcinoma.

Thymic squamous cell carcinoma (TSC) presents distinct immunohistochemical features with its expression of CD5 and CD117, both of which are rarely expressed in squamous cell carcinoma in other organs. We found insulinoma-associated-1 (INSM1) expression in some TSCs; thus, a series of thymic tumors were examined retrospectively. Using surgically resected thymic tumors (TSC, n = 35; thymic atypical carcinoid [TAC], n = 4; and thymoma, n = 112) and non-neoplastic thymic tissue (n = 26), we evaluated immunohistochemically the expressions of INSM1, ASCL1, SOX2, NE markers (synaptophysin, chromogranin A, and CD56), and conventional TSC markers (CD5 and CD117). INSM1 was expressed in 22 TSCs (63%), whereas the positive frequencies of synaptophysin, chromogranin A, and CD56 were limited to 13, 10, and 1 cases, respectively. The discordance was highly contrasted with concordantly positive TACs. INSM1 and NE makers were rarely expressed in thymomas. INSM1 expression in TSCs was also associated with CD5 expression, which was significantly less frequent in INSM1-negative TSCs. INSM1, ASCL1, and SOX2 expressions were correlated with one another, but none of the single transcription factors or their combinations is associated with NE expression. The non-neoplastic medullary thymic epithelium was dispersedly positive for INSM1, particularly around Hassall's corpuscles. Despite positive INSM1, a significant decrease in the frequency of NE maker expression may present as a diagnostic pitfall in TSCs. Furthermore, the discordance, which was inherent in the non-neoplastic thymic epithelium, might be a characteristic feature in TSCs.

Developmental dynamics of two bipotent thymic epithelial progenitor types

T cell development in the thymus is essential for cellular immunity and depends on the organotypic thymic epithelial microenvironment. In comparison with other organs, the size and cellular composition of the thymus are unusually dynamic, as exemplified by rapid growth and high T cell output during early stages of development, followed by a gradual loss of functional thymic epithelial cells and diminished naive T cell production with age1–10. Single-cell RNA sequencing (scRNA-seq) has uncovered an unexpected heterogeneity of cell types in the thymic epithelium of young and aged adult mice11–18; however, the identities and developmental dynamics of putative pre- and postnatal epithelial progenitors have remained unresolved1,12,16,17,19–27. Here we combine scRNA-seq and a new CRISPR–Cas9-based cellular barcoding system in mice to determine qualitative and quantitative changes in the thymic epithelium over time. This dual approach enabled us to identify two principal progenitor populations: an early bipotent progenitor type biased towards cortical epithelium and a postnatal bipotent progenitor population biased towards medullary epithelium. We further demonstrate that continuous autocrine provision of Fgf7 leads to sustained expansion of thymic microenvironments without exhausting the epithelial progenitor pools, suggesting a strategy to modulate the extent of thymopoietic activity.

Ectopic ocular tissue in testicular teratoma: A case report and review of the literature.

Introduction and importanceTeratoma is a common neoplasm in prepubertal and post-pubertal periods. It consists of various types of tissues arising from different germinal layers, endoderm, mesoderm, and ectoderm. Ectopic ocular tissue is a rare phenomenon, with only few reported cases in other locations.Case presentationThis is a 10-month-old boy who presented with a painless scrotal mass. Following orchidectomy, the excised mass confirmed the presence of uveal and retinal tissues originating in a benign testicular teratoma by histopathological examination.DiscussionChoroidal and retinal tissue are the most frequently encountered ectopic ocular tissue, while the least observed tissue is the lens. Most of the reported cases of ectopic ocular tissue present in ovarian teratomas. The only 2 previously reported cases of ocular-like tissue in testicular teratoma lack well-defined medullary epithelium, uveal, and retinal tissue as in our case.ConclusionTo our knowledge, developing ocular tissue in a testicular teratoma is extremely rare. Herein we report a unique case with mature defined ocular tissue within a testicular teratoma in an infant, which should not be overlooked.

Single-cell multiomics defines tolerogenic extrathymic Aire-expressing populations with unique homology to thymic epithelium.

The autoimmune regulator (Aire), a well-defined transcriptional regulator in the thymus, is also found in extrathymic Aire-expressing cells (eTACs) in the secondary lymphoid organs. eTACs are hematopoietic antigen-presenting cells and inducers of immune tolerance, but their precise identity has remained unclear. Here, we use single-cell multiomics, transgenic murine models, and functional approaches to define eTACs at the transcriptional, genomic, and proteomic level. We find that eTACs consist of two similar cell types: CCR7+ Aire-expressing migratory dendritic cells (AmDCs) and an Airehi population coexpressing Aire and retinoic acid receptor–related orphan receptor γt (RORγt) that we term Janus cells (JCs). Both JCs and AmDCs have the highest transcriptional and genomic homology to CCR7+ migratory dendritic cells. eTACs, particularly JCs, have highly accessible chromatin and broad gene expression, including a range of tissue-specific antigens, as well as remarkable homology to medullary thymic epithelium and RANK-dependent Aire expression. Transgenic self-antigen expression by eTACs is sufficient to induce negative selection and prevent autoimmune diabetes. This transcriptional, genomic, and functional symmetry between eTACs (both JCs and AmDCs) and medullary thymic epithelium—the other principal Aire-expressing population and a key regulator of central tolerance—identifies a core program that may influence self-representation and tolerance across the spectrum of immune development.

141 Translation and growth pathways are directly influenced by autoimmune regulator (Aire) in skin keratinocytes

Autoimmune regulator, Aire, is commonly known to function as a transcriptional regulator in medullary thymic epithelia. However, we and others have identified Aire to express and function in non-thymic tissues, including the skin, where it greatly influences inflammation and tumorigenesis. We report here that, within skin keratinocytes, Aire participates in a variety of cellular processes outside of its classically defined role in the nucleus. We employed a proximity based biotinylation screen (BioID) to examine the localization of Aire and its binding partners within keratinocytes. Aire is observed by structured illumination microscopy to localize in distinct subcellular compartments within the nucleus, cytoplasm, and along cytoskeletal tracks. Disease causing and function blocking mutations in Aire substantially alter these distribution patterns in keratinocytes, suggesting a link between Aire subcellular compartmentalization and pathogenesis. Using an isobaric labeling method (iTRAQ) coupled to tandem mass spectrometry, we identified 295 common Aire binding partners (99.0% probability), most of them novel, and quantitatively assessed the impact of Aire mutations on binding partner associations. Specifically, Aire binding partners associated with protein translation and cell growth (e.g. multiple 40S and 60S ribosomal protein subunits, cell growth-regulating nucleolar protein, eukaryotic translation initiation factors 4 and 5, elongation factor 1 alpha 1) were significantly altered in cells expressing mutant Aire compared to wild-type Aire. Serum pulse assays confirm a positive correlation between loss of wild-type Aire expression in keratinocytes and increased translation associated signaling (P-AKTS473, P-S6KT389, P-S6S235/S236, P-4EBP1S65, P-eIF4BS422, and P-eEF2KS366). These newly identified partners for Aire expand our understanding of Aire function in the skin and may provide a basis for the pro-tumorigenic role for Aire in skin cancers.

Medullary stromal cells synergize their production and capture of CCL21 for T-cell emigration from neonatal mouse thymus.

The release of newly selected αβT cells from the thymus is key in establishing a functional adaptive immune system. Emigration of the first cohorts of αβT cells produced during the neonatal period is of particular importance, because it initiates formation of the peripheral αβT-cell pool and provides immune protection early in life. Despite this, the cellular and molecular mechanisms of thymus emigration are poorly understood. We examined the involvement of diverse stromal subsets and individual chemokine ligands in this process. First, we demonstrated functional dichotomy in the requirement for CCR7 ligands and identified CCL21, but not CCL19, as an important regulator of neonatal thymus emigration. To explain this ligand-specific requirement, we examined sites of CCL21 production and action and found Ccl21 gene expression and CCL21 protein distribution occurred within anatomically distinct thymic areas. Although Ccl21 transcription was limited to subsets of medullary epithelium, CCL21 protein was captured by mesenchymal stroma consisting of integrin α7+ pericytes and CD34+ adventitial cells at sites of thymic exit. This chemokine compartmentalization involved the heparan sulfate-dependent presentation of CCL21 via its C-terminal extension, explaining the absence of a requirement for CCL19, which lacks this domain and failed to be captured by thymic stroma. Collectively, we identified an important role for CCL21 in neonatal thymus emigration, revealing the importance of this chemokine in initial formation of the peripheral immune system. Moreover, we identified an intrathymic mechanism involving cell-specific production and presentation of CCL21, which demonstrated a functional synergy between thymic epithelial and mesenchymal cells for αβT-cell emigration.

Ageing compromises mouse thymus function and remodels epithelial cell differentiation.

Ageing is characterised by cellular senescence, leading to imbalanced tissue maintenance, cell death and compromised organ function. This is first observed in the thymus, the primary lymphoid organ that generates and selects T cells. However, the molecular and cellular mechanisms underpinning these ageing processes remain unclear. Here, we show that mouse ageing leads to less efficient T cell selection, decreased self-antigen representation and increased T cell receptor repertoire diversity. Using a combination of single-cell RNA-seq and lineage-tracing, we find that progenitor cells are the principal targets of ageing, whereas the function of individual mature thymic epithelial cells is compromised only modestly. Specifically, an early-life precursor cell population, retained in the mouse cortex postnatally, is virtually extinguished at puberty. Concomitantly, a medullary precursor cell quiesces, thereby impairing maintenance of the medullary epithelium. Thus, ageing disrupts thymic progenitor differentiation and impairs the core immunological functions of the thymus.

Semaphorin 3A Negatively Affects Proliferation of Mouse Thymus Epithelial Cells In Vitro.

We studied effects of semaphorin 3A, keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), and their combinations on the proliferative activity of cortical (cTEC1-2) and medullary (mTEC3-10) thymus epithelium cell lines. Semaphorin 3A inhibited the proliferative activity of epithelial cells, while HGF and KGF, in contrast, exerted a stimulating effect. The effect of KGF and semaphorin 3A on different cell lines depended on the expression of receptors for these two factors. When the combination of two factors was used, semaphorin 3A was able to neutralize the stimulating effect of HGF and KGF. It can be assumed that semaphorin 3A synthesized in the thymus stroma, can act as a functional antagonist of HGF and KGF and have an inhibitory effect when these drugs are administered into the body for the therapeutic purpose of restoring thymus functions.

Intraocular medulloepithelioma - A review of clinical features, DICER 1 mutation, and management.

Intraocular medulloepithelioma is a nonhereditary neoplasm of childhood arising from primitive medullary epithelium. It most often involves the ciliary body. Most patients present between 2 and 10 years of age with loss of vision, pain, leucocoria, or conjunctival congestion. The mass appears as a grey-white ciliary body lesion with intratumoral cysts. Presence of a neoplastic cyclitic membrane with extension to retrolental region is characteristic. Secondary manifestations like cataract and neovascular glaucoma may be present in up to 50% and 60% patients, respectively. These could be the first signs for which, unfortunately, about 50% patients undergo surgery before recognition of the hidden tumor. Systemic correlation with pleuropulmonary blastoma (DICER1 gene) has been documented in 5% cases. Histopathology shows primitive neuroepithelial cells arranged as cords closely resembling the primitive retina. Histopathologically, the tumor is classified as teratoid (containing heteroplastic elements) and nonteratoid (containing medullary epithelial elements), each of which are further subclassified as benign or malignant. Retinoblastoma-like and sarcoma-like areas may be seen within the tissue. The treatment modality depends on tumor size and extent of invasion. For small localized tumors (≤3-4 clock hours), conservative treatments with cryotherapy, plaque radiotherapy, or partial lamellar sclerouvectomy (PLSU) have been used. Plaque brachytherapy is generally preferred for best tumor control. Advanced and extensive tumors require enucleation. Rare use of intra-arterial and intravitreal chemotherapy has been employed. Systemic prognosis is favorable, but those with extraocular extension and orbital involvement show risk for local recurrence and metastatic disease, which can lead to death.

Memory B cells are poised for robust antigen presentation by HLA-DO

Abstract The B cell is a uniquely efficient APC due to expression of BCR for antigen uptake and delivery to MHCII-enriched compartments (MIIC), and key regulatory molecules, invariant chain (Ii), HLA-DM and HLA-DO. All professional APCs express Ii and DM, whereas expression of DO is limited to B cells, certain DCs and thymic medullary epithelia. DO levels change dramatically in B cells entering or exiting the germinal center (GC). To determine effects of DO on other components of the MHCII pathway, we delineated the intracellular distribution of DO, DM, MHCII, and class II-associated CLIP in T2 cells with or without DO or DM expression using structured illumination microscopy. The distribution at steady state shows a very restricted lysosomal destination (LAMP1+) for DO and DM, and dual destinations (surface and LAMP1+) for CLIP and MHCII. DO expression increased overall CLIP compared to DM+DO-cells, but almost doubled the percent of CLIP co-localized with LAMP1, establishing peptide exchange potential (PEP) within MIICs, but not any other compartments or the cell surface. PEP enhancement associated with DO expression is likely due to its regulation of DM activity, as neither the overall CLIP level nor the percent of DR in MIICs increased. We then evaluated the extent of PEP in distinct primary B cell populations isolated from human tonsils, including memory (CD38−/IgD−), naïve (CD38−/IgD+), and GC (CD38+/IgD−) B cells. The measurement shows PEPMemory (significantly) &amp;gt; PEPNaïve &amp;gt; PEPGC−, although the percent of CLIP among all class II peptides is naïve &amp;gt; memory &amp;gt;&amp;gt; GC. These results argue that DO expression in memory B cells equips them for more efficient APC function upon re-encounter with antigen.

DNA breaks and chromatin structural changes enhance the transcription of autoimmune regulator target genes

The autoimmune regulator (AIRE) protein is the key factor in thymic negative selection of autoreactive T cells by promoting the ectopic expression of tissue-specific genes in the thymic medullary epithelium. Mutations in AIRE cause a monogenic autoimmune disease called autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. AIRE has been shown to promote DNA breaks via its interaction with topoisomerase 2 (TOP2). In this study, we investigated topoisomerase-induced DNA breaks and chromatin structural alterations in conjunction with AIRE-dependent gene expression. Using RNA sequencing, we found that inhibition of TOP2 religation activity by etoposide in AIRE-expressing cells had a synergistic effect on genes with low expression levels. AIRE-mediated transcription was not only enhanced by TOP2 inhibition but also by the TOP1 inhibitor camptothecin. The transcriptional activation was associated with structural rearrangements in chromatin, notably the accumulation of γH2AX and the exchange of histone H1 with HMGB1 at AIRE target gene promoters. In addition, we found the transcriptional up-regulation to co-occur with the chromatin structural changes within the genomic cluster of carcinoembryonic antigen-like cellular adhesion molecule genes. Overall, our results suggest that the presence of AIRE can trigger molecular events leading to an altered chromatin landscape and the enhanced transcription of low-expressed genes.

Immunolocalization of novel corticomedullary tubule injury markers in Cynomolgus monkeys treated with amphotericin B.

Amphotericin B (AmpB) nephrotoxicity was used to assess the utility of drug‑induced kidney injury (DIKI) biomarkers in an exploratory study in male cynomolgus monkeys. All animals had quantifiable levels of AmpB in plasma on days 1 and 4. There were no clinical signs of AmpB‑induced toxicity in this study. The gold standard method used to confirm AmpB‑induced DIKI was anatomic pathology which revealed microscopic lesions with varying grades of severity. Immunolocalization of alpha‑1 microglobulin (α‑1M), kidney injury molecule 1 (KIM‑1), osteopontin (OPN) and neutrophil gelatinase‑associated lipocalin (NGAL) proteins was evaluated in formalin‑fixed, paraffin‑embedded monkey kidney tissue sections. AmpB related immunoreactivities were identified in distinct nephron segments of treated monkeys including α‑1M in damaged proximal tubule epithelium, KIM‑1 in damaged medullary tubule epithelium, OPN mostly in the infiltrating cells of cortical tubule interstitium, and NGAL in the granular and cellular cast in dilatated cortical tubules. Variations in α‑1M, KIM‑1, OPN and NGAL immunolocalization appear as promising DIKI protein biomarkers when monitoring for AmpB‑induced corticomedullary tubule injury in male cynomolgus monkeys.

Chemosensory cholinergic signaling network in the thymic medullary epithelium

Objective: A subset of medullary epithelial cells in the thymus (mTECs) was previously shown to be cholinergic and express components of bitter taste cascade. In this study we set out to further characterize these cells and elucidate their function.

CCR7 Controls Thymus Recirculation, but Not Production and Emigration, of Foxp3(+) T Cells.

SummaryCurrent models of Foxp3+ regulatory T cell (Treg) development involve CCR7-mediated migration of thymocytes into the thymus medulla to enable essential interactions with medullary epithelium. However, increased Foxp3+ thymic Treg numbers in Ccr7−/− mice challenge this view, and the role of CCR7 in Treg development, emigration, and/or recirculation is unknown. Here, we have examined CCR7 and Rag2pGFP levels during Treg development and generated Rag2pGFPCcr7−/− mice to study its impact on the intrathymic Treg pool. We reveal surprising developmental heterogeneity in thymocytes described as Treg precursors, showing that they contain recirculating CCR6+CCR7−Rag2pGFP− T cells. Although CCR7 defines bona fide Rag2GFP+ Treg precursors, it is not required for Treg production and emigration. Rather, we show that lack of CCR7 renders the thymus more receptive to Treg thymus homing. Our study reveals a role for CCR7 in limiting Treg recirculation back to the thymus and enables separation of the mechanisms controlling Treg production and thymic recirculation.

Adult Thymic Medullary Epithelium Is Maintained and Regenerated by Lineage-Restricted Cells Rather Than Bipotent Progenitors

Medullary thymic epithelial cells (mTECs) play an essential role in establishing self-tolerance in Tcells. mTECs originate from bipotent TEC progenitors that generate both mTECs and cortical TECs (cTECs), although mTEC-restricted progenitors also have been reported. Here, we report invivo fate-mapping analysis of cells that transcribe β5t, a cTEC trait expressed in bipotent progenitors, during a given period in mice. We show that, in adult mice, most mTECs arederived from progenitors that transcribe β5t during embryogenesis and the neonatal period up to 1week of age. The contribution of adult β5t(+) progenitors was minor even during injury-triggered regeneration. Our results further demonstrate that adult mTEC-restricted progenitors are derived from perinatal β5t(+) progenitors. These results indicate that the adult thymic medullary epithelium is maintained and regenerated by mTEC-lineage cells that pass beyond the bipotent stage during early ontogeny.

Chemosensory cholinergic signaling network in the thymic medullary epithelium

Chemosensory cholinergic signaling network in the thymic medullary epithelium

New Insights Into the Development of Infantile Intraocular Medulloepithelioma

To define the maturational sequence of 3 infantile intraocular medulloepitheliomas. Retrospective clinicohistopathologic and immunohistochemical study. Immunoreactivity of paraffin sections for CRX (cone-rod homebox transcription factor) and NeuN (biomarker for neuronal differentiation) were investigated together with other biomarkers, including S100, glial fibrillary acidic protein, epithelial membrane antigen, and various cytokeratins. Three infants (aged 1, 6, and 8 months) had iris neovascularization, 2 had anterior ciliary body tumors, and 1 a posterior tumor associated with a retinochoroidal coloboma. Each tumor displayed a premedullary monolayer of cuboidal epithelium that was S100(+), NeuN(-), and CRX(-) and that transitioned into a multilaminar medullary epithelium forming neurotubules with adluminal cells that were CRX(+). NeuN first appeared in ablumenal neurotubular cells in 1 tumor and was also discovered among neuroblast-appearing cells in another. The third tumor associated with a coloboma was CRX(-) and NeuN(-). A simple premedullary epithelial monolayer appears to be the fundamental source for the tumor and its multilaminar medullary epithelium. CRX(+) and NeuN(+) cells within the multilayered medullary layer approximate expression patterns similar to those found in retinal development and differentiation. Discovery of these biomarkers in the neoplastic ciliary epithelium in a small number of tumors indicates preliminarily that the most anterior layers of the optic cup have a retained retinal and neuroglial differentiation potentiality. The third case was CRX(-) and NeuN(-) and possibly arose from embryonic pigment epithelium at the edge of the retinochoroidal coloboma. These immunohistochemical findings offer histogenetic and potential diagnostic insights.