Immunohistochemical Localization of Cytokeratins in the Junctional Region of Ectoderm and Endoderm

Although tridermic species have two junctional regions of ectoderm and endoderm between their epidermis and digestive tract, we actually know little about these particular boundaries. Cytokeratins are the major intermediate filaments of epithelial cells and show a high degree of tissue specificity. Therefore, to characterize the epithelial cells in the junctional region of ectoderm and endoderm, we immunohistochemically examined the localization of cytokeratins 5, 7/17, 14, 18, Sox17, and alpha-fetoprotein (AFP) in the oropharyngeal and anorectal regions during the mouse gastrulation process. At embryonic day (E) 9.5, cytokeratins 5, 7/17, 14, and 18 were detected in all epithelial cells of the oropharyngeal region. At E12.5, cytokeratin 5-positive cells were not observed in the middle area of the oral cavity; however, the immunoreactivity was strong in the anterior and posterior areas. The immunoreaction of cytokeratins 18 was seen only in the middle and posterior areas of the oral mucosa. Cytokeratins 7/17 and 14 were localized in all areas of the oropharyngeal region. Sox17 and AFP, which are endodermal markers, were detected in the middle and posterior areas of the oral mucosa, but not in the anterior area. Moreover, this same localization pattern of cytokeratins also existed in the anorectal region of the E12.5 embryo, suggesting that the localization of cytokeratins and endodermal markers might give an implication for the boundary between ectoderm and endoderm. These results also suggest that these cytokeratins are useful molecules for monitoring the epithelial cell differentiation in the junctional region of the germ layers. Anat Rec, 2010. © 2010 Wiley-Liss, Inc.link_to_subscribed_fulltex

Ruxolitinib Alleviates Inflammation and Fortifies Skin Barrier Function Through Dampening IL-13

\ua9 2025 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.Atopic dermatitis (AD) is a prevalent inflammatory skin disorder characterized by an impaired skin barrier, dysregulated immune system and pruritis. Emerging pharmaceutical therapies for AD include selective Janus kinase (JAK) inhibitors such as ruxolitinib, the first dual JAK1/JAK2 inhibitor approved by the US Food and Drug Administration. This study aimed to evaluate the effects of ruxolitinib on AD-related symptoms using mouse and human skin models. AD-related symptoms were assessed in MC903/ruxolitinib-treated mice, including ear swelling, histological analysis, pruritus, serum biomarker quantification and immune cell analysis. Additionally, immunohistochemistry and transcriptome analysis were conducted on AD-related cytokine-treated reconstructed human skin (RHS) and ruxolitinib-treated human skin explants with and without tape-stripping. Ruxolitinib-treated mice exhibited reduced inflammation, including decreased ear swelling and diminished pruritus. Furthermore, reductions in immune cell populations, including T cells and serum biomarker IL-13, were observed in ruxolitinib-treated mice. Transcriptome analysis revealed increased STAT3 expression and decreased skin barrier gene FLG in AD-related cytokine-treated RHS. Regardless of tape stripping, ruxolitinib-treated skin explants exhibited decreased IL13RA1 expression and increased expression of skin barrier genes FLG, FLG2 and LOR. Ruxolitinib treatment in mice resulted in decreased inflammation and pruritus, along with increased expression of skin barrier proteins through downregulation of IL-13. Consistently, ruxolitinib-treated human skin explants demonstrated enhanced expression of skin barrier proteins, while IL-13 treatment of RHS led to downregulation of these proteins. These findings support data from human clinical trials indicating reduced SCORAD, pruritus and inflammatory phenotypes in AD patients treated with ruxolitinib

Mutations in the gene encoding pejvakin, a newly identified protein of the afferent auditory pathway, cause DFNB59 auditory neuropathy

International audienceAuditory neuropathy is a particular type of hearing impairment in which neural transmission of the auditory signal is impaired, while cochlear outer hair cells remain functional. Here we report on DFNB59, a newly identified gene on chromosome 2q31.1–q31.3 mutated in four families segregating autosomal recessive auditory neuropathy. DFNB59 encodes pejvakin, a 352-residue protein. Pejvakin is a paralog of DFNA5, a protein of unknown function also involved in deafness. By immunohistofluorescence, pejvakin is detected in the cell bodies of neurons of the afferent auditory pathway. Furthermore, Dfnb59 knock-in mice, homozygous for the R183W variant identified in one DFNB59 family, show abnormal auditory brainstem responses indicative of neuronal dysfunction along the auditory pathway. Unlike previously described sensorineural deafness genes, all of which underlie cochlear cell pathologies, DFNB59 is the first human gene implicated in nonsyndromic deafness due to a neuronal defect

Epidermal cornification is preceded by the expression of a keratinocyte-specific set of pyroptosis-related genes

Abstract The homeostasis of the epidermis depends on keratinocyte differentiation and cornification, a mode of programmed cell death that does not elicit inflammation. Here, we report that cornification is associated with the expression of specific genes that control multiple steps of pyroptosis, another form of cell death that involves the processing and release of interleukin-1 family (IL1F) cytokines. Expression levels of pro-inflammatory IL1A and IL1B and of the pyroptotic pore-forming gasdermin (GSDM) D were downregulated during terminal differentiation of human keratinocytes in vitro. By contrast, negative regulators of IL-1 processing, including NLR family pyrin domain containing 10 (NLRP10) and pyrin domain-containing 1 (PYDC1), the anti-inflammatory IL1F members IL-37 (IL1F7) and IL-38 (IL1F10), and GSDMA, were strongly induced in differentiated keratinocytes. In human tissues, these keratinocyte differentiation-associated genes are expressed in the skin at higher levels than in any other organ, and mammalian species, that have lost the epidermal cornification program during evolution, i.e. whales and dolphins, lack homologs of these genes. Together, our results suggest that human epidermal cornification is accompanied by a tight control of pyroptosis and warrant further studies of potential defects in the balance between cornification and pyroptosis in skin pathologies