Interleukin-13 maintains the stemness of conjunctival epithelial cell cultures prepared from human limbal explants

Paneth cells protect intestinal stem cell niche to alleviate deoxynivalenol-induced intestinal injury

Deoxynivalenol (DON) is a common toxin in grains and feeds, and DON exposure triggers severe small intestinal injury and inflammation, which harms the health of humans and livestock. DON treatment leads to a decrease in Paneth cells, whereas the role of Paneth cells in DON-induced intestinal injury is poorly understood. We utilized dithizone (40 mg/kg) to keep murine Paneth cell number at a low level. The results showed that dithizone-mediated long-term disruption of Paneth cells aggravated intestinal injury, intestinal stem cell (ISC) loss, and microbiota disorder in DON (2 mg/kg)-treated mice. Unexpectedly, the number of goblet cells and proliferative cells was boosted in mice treated with dithizone and DON. After dithizone and DON treatments, the Firmicutes/Bacteroidetes (F/B) ratio was reduced, and the increased abundance of Dubosiella and the decreased abundance of Lactobacillus were observed in mice. The functional recovery of Paneth cells by lysozyme (200 U/day) supplementation improved intestinal injury and ISC loss in mice after DON challenge. In addition, lysozyme also promoted the growth and ISC activity of intestinal organoids. Taken together, these results demonstrate the protective role of Paneth cells in DON-induced intestinal injury. Our study raises a novel target, Paneth cell, for the treatment of DON exposure.

Development of an oral mucosal irritation test using a three-dimensional human buccal oral mucosal model

The oral mucosa can become irritated by oral care products and lip cosmetics. Therefore, it is important to determine the irritation potential of their ingredients and products during safety evaluations. We developed a method for oral mucosal irritation test using EpiOral, which is a three-dimensional cultured model. Exposure of sodium lauryl sulphate (SLS) to EpiOral showed a dose-dependent decrease in cell viability. Under 120 min exposure conditions, SLS irritation was detected when 60% cell viability was set as a criterion. Evaluation of the irritancy of SLS and four other raw materials used in oral products at three laboratories under the above conditions confirmed good transferability of the test. Focused on the similarity of the oral and eye mucous, 32 chemicals categorised by the UN-GHS eye-irritation classification were evaluated to ensure the reliability of our criteria at these laboratories. The concordance rate between the UN-GHS classification and our test results was 100% for irritants and 60% for non-irritants. The good intra-laboratory reproducibility of our test was confirmed from the evaluation results of negative and positive controls, and the good inter-laboratory reproducibility was confirmed from the results of 32 chemicals. These findings showed that oral mucosal irritation can be evaluated using EpiOral.

Interleukin-13 increases the stemness of limbal epithelial stem cells cultures

This study aimed to determine the effect of interleukin-13 (IL13) on the stemness, differentiation, proliferation, clonogenicity, and morphology of cultured limbal epithelial cells (LECs). Human limbal explants were used to culture LECs up to the second passage (P0-P2) with or without IL13 (IL13+ and IL13-, respectively). Cells were analyzed by qPCR (for the expression of ΔNp63α, BMI-1, keratin (K) 3, K7, K12, K14, K17, mucin 4, and MKI67) and immunofluorescence staining for p63α. The clonogenic ability was determined by colony-forming assay (CFA), and their metabolic activity was measured by WST-1 assay. The results of the CFA showed a significantly increased clonogenic ability in P1 and P2 cultures when LECs were cultured with IL13. In addition, the expression of putative stem cell markers (ΔNp63α, K14, and K17) was significantly higher in all IL13+ cultures compared to IL13-. Similarly, immunofluorescence analysis showed a significantly higher percentage of p63α positive cells in P2 cultures with IL13 than without it. LECs cultures without IL13 lost their cuboidal morphology with a high nucleocytoplasmic ratio after P1. The use of IL13 also led to significantly higher proliferation in P2, which can be reflected by a higher ability to reach confluence in P2 cultures. On the other hand, IL13 had no effect on corneal epithelial cell differentiation (K3 and K12 expression), and the expression of the conjunctival marker K7 significantly increased in all IL13+ cultures compared to the respective cell culture without IL13. This study showed that IL13 enhanced the stemness of LECs by increasing the clonogenicity and the expression of putative stem cell markers of LECs while maintaining their stem cell morphology. We established IL13 as a culture supplement for LESCs, which increases their stemness potential in culture, even after the second passage, and may lead to the greater success of LESCs transplantation in patients with LSCD.

Anti-Ro/SSA and/or anti-La/SSB antibodies are associated with adverse IVF and pregnancy outcomes

Anti-Ro/SSA and/or anti-La/SSB antibodies (anti-SSA/SSB) were reported to increase the risk of recurrent pregnancy loss. However, the effects of anti-SSA/SSB antibodies on in-vitro fertilization (IVF) and pregnancy outcomes were still unclear. The purpose of the study was to determine whether anti-SSA/SSB antibodies were detrimental to IVF and pregnancy outcomes. This study included 55 anti-SSA/SSB antibodies-positive women and 61 anti-SSA/SSB antibodies-negative control women receiving gonadotropin-releasing hormone (GnRH) agonist long protocol (n = 30 and 39, respectively) or GnRH antagonist protocol (n = 25 and 22, respectively) for in-vitro fertilization and embryo transfer (IVF-ET). The impact of anti-SSA/SSB antibodies on immune-related indicators, fertilization, embryo development and pregnancy outcomes were analyzed. With either GnRH agonist or antagonist protocol, women with anti-SSA/SSB had higher levels of peripheral blood cytokines, including TNF-α and IL-17A, lower levels of peripheral blood Th and NK cells, and poor IVF outcomes, including lower number of retrieved oocytes and embryos, lower M II oocytes rate, blastocyst formation rate, and perfect and available embryo rates. Moreover, clinical pregnancy rate, implantation rate, take-home baby rate, and birth weight were significantly lower in the study group as compared with those of the control group. In conclusion, women with anti-SSA/SSB are associated with adverse IVF and pregnancy outcomes. Screening for these antibodies and proper counselling of couples undergoing IVF-ET should be considered. Underlying immunopathology associated with SSA/SSB antibodies and reproduction should be explored further.

Characterisation of Gel-Forming Mucins Produced In Vivo and In Ex Vivo Conjunctival Explant Cultures

One key element to the health of the ocular surface encompasses the presence of gel-forming mucins in the pre-ocular tear film. Conjunctival goblet cells are specialized epithelial cells that secrete mucins necessary for tear film stability and general homeostasis. Their dysfunction can be linked to a range of ocular surface inflammation disorders and chronic injuries. To obtain new perspectives and angles to tackle mucin deficiency, the need for an accurate evaluation of their presence and corresponding mucin secretion in ex vivo conjunctival cultures has become a requisite. In vitro, goblet cells show a significant decrease in the production and secretion of gel-forming mucins, accompanied by signs of dedifferentiation or transdifferentiation. Explant cultures on laminin-treated CLP-PEG hydrogels can, however, support the production of gel-forming mucins. Together, we challenge the current paradigm to evaluate the presence of cultured goblet cells solely based on their general mucin (MUC) content through imaging analyses, showing the need for additional techniques to assess the functionality of goblet cells. In addition, we broadened the gel-forming mucin profile of in vivo goblet cells with MUC5B and MUC6, while MUC2 and MUC6 is added to the profile of cultured goblet cells.

The foggy world(s) of p63 isoform regulation in normal cells and cancer

The p53 family member p63 exists as two major protein variants (TAp63 and ΔNp63) with distinct expression patterns and functional properties. Whilst downstream target genes of p63 have been studied intensively, how p63 variants are themselves controlled has been relatively neglected. Here, we review advances in understanding ΔNp63 and TAp63 regulation, highlighting their distinct pathways. TAp63 has roles in senescence and metabolism, and in germ cell genome maintenance, where it is activated post-transcriptionally by phosphorylation cascades after DNA damage. The function and regulation of TAp63 in mesenchymal and haematopoietic cells is less clear but may involve epigenetic control through DNA methylation. ΔNp63 functions to maintain stem/progenitor cells in various epithelia and is overexpressed in squamous and certain other cancers. ΔNp63 is transcriptionally regulated through multiple enhancers in concert with chromatin modifying proteins. Many signalling pathways including growth factors, morphogens, inflammation, and the extracellular matrix influence ΔNp63 levels, with inconsistent results reported. There is also evidence for reciprocal regulation, including ΔNp63 activating its own transcription. ΔNp63 is downregulated during cell differentiation through transcriptional regulation, while post-transcriptional events cause proteasomal degradation. Throughout the review, we identify knowledge gaps and highlight discordances, providing potential explanations including cell-context and cell-matrix interactions. Identifying individual p63 variants has roles in differential diagnosis and prognosis, and understanding their regulation suggests clinically approved agents for targeting p63 that may be useful combination therapies for selected cancer patients. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Discontinuous transcription of ribosomal DNA in human cells

Numerous studies show that various genes in all kinds of organisms are transcribed discontinuously, i.e. in short bursts or pulses with periods of inactivity between them. But it remains unclear whether ribosomal DNA (rDNA), represented by multiple copies in every cell, is also expressed in such manner. In this work, we synchronized the pol I activity in the populations of tumour derived as well as normal human cells by cold block and release. Our experiments with 5-fluorouridine (FU) and BrUTP confirmed that the nucleolar transcription can be efficiently and reversibly arrested at +4°C. Then using special software for analysis of the microscopic images, we measured the intensity of transcription signal (incorporated FU) in the nucleoli at different time points after the release. We found that the ribosomal genes in the human cells are transcribed discontinuously with periods ranging from 45 min to 75 min. Our data indicate that the dynamics of rDNA transcription follows the undulating pattern, in which the bursts are alternated by periods of rare transcription events.