Disruption of the epidermal barrier contributes to skin disorders such as atopic dermatitis and psoriasis. The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, plays a key role in skin homeostasis and immune regulation. While traditionally associated with toxicity, AhR has emerged as a promising therapeutic target, particularly via tryptophan-derived indoles. To support AhR research in a dermatological context, we developed AhaRaCaT, a stable luciferase-based reporter cell line derived from human keratinocytes (HaCaT), enabling the assessment of AhR transcriptional activity in a skin-relevant model. We characterized the inducibility of AhaRaCaT in response to model AhR ligands (TCDD, BaP, FICZ) in dose- and time-dependent assays. Antagonist profiling with MNF, CH223191, GNF, carvone, and jasmone yielded IC50 values over 4- and 24-hour exposures. A panel of indoles previously studied in other models was evaluated for AhR activation, revealing a robust luciferase response at 4 h that declined at 24 h, consistent with trends observed in other cell types. Selected indoles also induced CYP1A1 mRNA expression and reversed cytokine-induced downregulation of filaggrin in HaCaT cells, highlighting their potential in mitigating inflammation-associated skin barrier defects. In summary, the AhaRaCaT cell line offers a sensitive and physiologically relevant tool for studying AhR signaling in skin, with broad applications in toxicology, dermatological research, and the development of AhR-targeted therapies for inflammatory skin diseases.

• Keywords
• Aryl hydrocarbon receptor, FLG, Filaggrin, HaCaT cell line, Indole derivatives, Reporter gene assay,
• MeSH
• HaCaT Cells MeSH
• Cell Line MeSH
• Cytochrome P-450 CYP1A1 genetics   metabolism   MeSH
• Filaggrin Proteins MeSH
• Indoles * pharmacology   toxicity   MeSH
• Keratinocytes * drug effects   metabolism   MeSH
• Skin * drug effects   metabolism   MeSH
• Humans MeSH
• Ligands MeSH
• Luciferases genetics   metabolism   MeSH
• Receptors, Aryl Hydrocarbon * metabolism   genetics   agonists   antagonists & inhibitors   MeSH
• Genes, Reporter MeSH
• Basic Helix-Loop-Helix Transcription Factors * metabolism   genetics   agonists   MeSH
• Dose-Response Relationship, Drug MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• AHR protein, human MeSH Browser
• CYP1A1 protein, human MeSH Browser
• Cytochrome P-450 CYP1A1 MeSH
• Filaggrin Proteins MeSH
• FLG protein, human MeSH Browser
• Indoles * MeSH
• Ligands MeSH
• Luciferases MeSH
• Receptors, Aryl Hydrocarbon * MeSH
• Basic Helix-Loop-Helix Transcription Factors * MeSH

In electroreceptive jawed fishes and amphibians, individual lateral line placodes form lines of neuromasts on the head containing mechanosensory hair cells, flanked by fields of ampullary organs containing electroreceptors-modified hair cells that respond to weak electric fields. Extensively shared gene expression between neuromasts and ampullary organs suggests that conserved molecular mechanisms are involved in their development, but a few transcription factor genes are restricted either to the developing electrosensory or mechanosensory lateral line. Here, we used CRISPR/Cas9-mediated mutagenesis in G0-injected sterlet embryos (Acipenser ruthenus, a sturgeon) to test the function of three such genes. We found that the 'hair cell' transcription factor gene Atoh1 is required for both hair cell and electroreceptor differentiation in sterlet, and for Pou4f3 and Gfi1 expression in both neuromasts and ampullary organs. These data support the conservation of developmental mechanisms between hair cells and electroreceptors. Targeting ampullary organ-restricted Neurod4 did not yield any phenotype, potentially owing to redundancy with other Neurod genes that we found to be expressed in sterlet ampullary organs. After targeting mechanosensory-restricted Foxg1, ampullary organs formed within neuromast lines, suggesting that FoxG1 normally represses their development, whether directly or indirectly. We speculate that electrosensory organs may be the 'default' developmental fate of lateral line primordia in electroreceptive vertebrates.

• Keywords
• Acipenser ruthenus, Atoh1, Foxg1, ampullary organs, developmental biology, lateral line, neuromasts, sterlet sturgeon,
• MeSH
• Cell Differentiation MeSH
• Forkhead Transcription Factors * metabolism   genetics   MeSH
• Lateral Line System * embryology   metabolism   MeSH
• Fish Proteins * metabolism   genetics   MeSH
• Fishes * embryology   genetics   MeSH
• Basic Helix-Loop-Helix Transcription Factors * metabolism   genetics   MeSH
• Hair Cells, Auditory * physiology   MeSH
• Gene Expression Regulation, Developmental MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Forkhead Transcription Factors * MeSH
• Fish Proteins * MeSH
• Basic Helix-Loop-Helix Transcription Factors * MeSH

BACKGROUND: Profiling studies in small-cell lung cancer (SCLC) have mainly focused on primary tumors, omitting the potential molecular changes that might occur during lymphatic metastasis formation. Here, we assessed the molecular discordance between primary SCLCs and corresponding lymph node (LN) metastases in the light of subtype distribution and expression of clinically relevant proteins. METHODS: Comparative profiling of 32 surgically resected primary SCLCs and their LN metastases was achieved by RNA expression analysis and immunohistochemistry (IHC). In addition to subtype markers (ASCL1, NEUROD1, POU2F3, and YAP1), the expression of nine cancer-specific proteins was evaluated. RESULTS: The selected clinically relevant molecules showed no significant differences in their RNA expression profile when assessing the primary tumors and their corresponding LN metastases. Nevertheless, IHC analyses revealed significantly higher DLL3 expression in the primary tumors than in the LN metastases (P = 0.008). In contrast, NEUROD1 expression was significantly lower in the primary tumors (versus LN metastases, P < 0.001). No statistically significant difference was found by IHC analysis in the case of other clinically relevant proteins. Concerning SCLC molecular subtypes, a change in subtype distribution was detected in 21 cases. Phenotype switching from neuroendocrine (NE) subtypes toward non-NE lesions and from non-NE landscape toward NE subtypes were both detected. CONCLUSIONS: Although the molecular landscape of SCLC LN metastases largely resembles that of the tumor of origin, key differences exist in terms of DLL3 and NEUROD1 expression, and in subtype distribution. These diagnostic pitfalls should be considered when establishing the tumors' molecular profile for future clinical trials solely based on LN biopsies.

• Keywords
• intertumoral heterogeneity, metastasis, small-cell lung cancer, subtypes,
• MeSH
• Immunohistochemistry MeSH
• Middle Aged MeSH
• Humans MeSH
• Lymphatic Metastasis * pathology   MeSH
• Small Cell Lung Carcinoma * surgery   pathology   genetics   MeSH
• Biomarkers, Tumor genetics   MeSH
• Lung Neoplasms * pathology   surgery   genetics   MeSH
• Aged MeSH
• Basic Helix-Loop-Helix Transcription Factors genetics   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Comparative Study MeSH
• Names of Substances
• Biomarkers, Tumor MeSH
• Basic Helix-Loop-Helix Transcription Factors MeSH

Transcription factors of the bHLH-PAS family play vital roles in animal development, physiology, and disease. Two members of the family require binding of low-molecular weight ligands for their activity: the vertebrate aryl hydrocarbon receptor (AHR) and the insect juvenile hormone receptor (JHR). In the fly Drosophila melanogaster, the paralogous proteins GCE and MET constitute the ligand-binding component of JHR complexes. Whilst GCE/MET and AHR are phylogenetically heterologous, their mode of action is similar. JHR is targeted by several synthetic agonists that serve as insecticides disrupting the insect endocrine system. AHR is an important regulator of human endocrine homeostasis, and it responds to environmental pollutants and endocrine disruptors. Whether AHR signaling is affected by compounds that can activate JHR has not been reported. To address this question, we screened a chemical library of 50,000 compounds to identify 93 novel JHR agonists in a reporter system based on Drosophila cells. Of these compounds, 26% modulated AHR signaling in an analogous reporter assay in a human cell line, indicating a significant overlap in the agonist repertoires of the two receptors. To explore the structural features of agonist-dependent activation of JHR and AHR, we compared the ligand-binding cavities and their interactions with selective and common ligands of AHR and GCE. Molecular dynamics modeling revealed ligand-specific as well as conserved side chains within the respective cavities. Significance of predicted interactions was supported through site-directed mutagenesis. The results have indicated that synthetic insect juvenile hormone agonists might interfere with AHR signaling in human cells.

• Keywords
• aryl hydrocarbon receptor, endocrine disruptors, high-throughput screening, juvenile hormone receptor, ligand binding domain,
• MeSH
• Cell Line MeSH
• Drosophila melanogaster metabolism   MeSH
• Juvenile Hormones MeSH
• Small Molecule Libraries pharmacology   MeSH
• Humans MeSH
• Ligands MeSH
• Drosophila Proteins * agonists   metabolism   chemistry   genetics   MeSH
• Receptors, Aryl Hydrocarbon * agonists   metabolism   chemistry   genetics   MeSH
• Signal Transduction drug effects   MeSH
• Basic Helix-Loop-Helix Transcription Factors * agonists   metabolism   chemistry   genetics   MeSH
• Protein Binding MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• AHR protein, human MeSH Browser
• Juvenile Hormones MeSH
• Small Molecule Libraries MeSH
• Ligands MeSH
• Drosophila Proteins * MeSH
• Receptors, Aryl Hydrocarbon * MeSH
• Basic Helix-Loop-Helix Transcription Factors * MeSH

BACKGROUND: Head and neck paragangliomas (HNPGLs) are typically slow-growing, hormonally inactive tumors of parasympathetic paraganglia. Inactivation of prolyl-hydroxylase domain-containing 2 protein causing indirect gain-of-function of hypoxia-inducible factor-2α (HIF-2α), encoded by EPAS1, was recently shown to cause carotid body hyperplasia. We previously described a syndrome with multiple sympathetic paragangliomas caused by direct gain-of-function variants in EPAS1 (Pacak-Zhuang syndrome, PZS) and developed a corresponding mouse model. METHODS: We evaluated a cohort of patients with PZS (n = 9) for HNPGL by positron emission tomography, magnetic resonance imaging, and computed tomography and measured carotid body size compared to literature reference values. Resected tumors were evaluated by histologic sectioning and staining. We evaluated the corresponding mouse model at multiple developmental stages (P8 and adult) for lesions of the head and neck by high resolution ex vivo imaging and performed immunohistochemical staining on histologic sections of the identified lesions. RESULTS: hree patients had imaging consistent with HNPGL, one of which warranted resection and was confirmed on histology. Three additional patients had carotid body enlargement (Z-score > 2.0), and 3 had carotid artery malformations. We found that 9 of 10 adult variant mice had carotid body tumors and 6 of 8 had a paraganglioma on the cranio-caval vein, the murine homologue of the superior vena cava; these were also found in 4 of 5 variant mice at post-natal day 8. These tumors and the one resected from a patient were positive for tyrosine hydroxylase, synaptophysin, and chromogranin A. Brown fat in a resected patient tumor carried the EPAS1 pathogenic variant. CONCLUSIONS: These findings (1) suggest HNPGL as a feature of PZS and (2) show that these pathogenic variants are sufficient to cause the development of these tumors, which we believe represents a continuous spectrum of disease starting from hyperplasia.

• MeSH
• Adult MeSH
• Carotid Body pathology   diagnostic imaging   MeSH
• Middle Aged MeSH
• Humans MeSH
• Magnetic Resonance Imaging MeSH
• Disease Models, Animal MeSH
• Mice MeSH
• Head and Neck Neoplasms * genetics   pathology   diagnostic imaging   MeSH
• Paraganglioma * genetics   pathology   diagnostic imaging   MeSH
• Tomography, X-Ray Computed MeSH
• Positron-Emission Tomography MeSH
• Syndrome MeSH
• Basic Helix-Loop-Helix Transcription Factors * genetics   MeSH
• Animals MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• endothelial PAS domain-containing protein 1 MeSH Browser
• Basic Helix-Loop-Helix Transcription Factors * MeSH

Formation of the apical hook in etiolated dicot seedlings results from differential growth in the hypocotyl apex and is tightly controlled by environmental cues and hormones, among which auxin and gibberellins (GAs) play an important role. Cell expansion is tightly regulated by the cell wall, but whether and how feedback from this structure contributes to hook development are still unclear. Here, we show that etiolated seedlings of the Arabidopsis (Arabidopsis thaliana) quasimodo2-1 (qua2) mutant, defective in pectin biosynthesis, display severe defects in apical hook formation and maintenance, accompanied by loss of asymmetric auxin maxima and differential cell expansion. Moreover, qua2 seedlings show reduced expression of HOOKLESS1 (HLS1) and PHYTOCHROME INTERACTING FACTOR4 (PIF4), which are positive regulators of hook formation. Treatment of wild-type seedlings with the cellulose inhibitor isoxaben (isx) also prevents hook development and represses HLS1 and PIF4 expression. Exogenous GAs, loss of DELLA proteins, or HLS1 overexpression partially restore hook development in qua2 and isx-treated seedlings. Interestingly, increased agar concentration in the medium restores, both in qua2 and isx-treated seedlings, hook formation, asymmetric auxin maxima, and PIF4 and HLS1 expression. Analyses of plants expressing a Förster resonance energy transfer-based GA sensor indicate that isx reduces accumulation of GAs in the apical hook region in a turgor-dependent manner. Lack of the cell wall integrity sensor THESEUS 1, which modulates turgor loss point, restores hook formation in qua2 and isx-treated seedlings. We propose that turgor-dependent signals link changes in cell wall integrity to the PIF4-HLS1 signaling module to control differential cell elongation during hook formation.

• MeSH
• Arabidopsis * genetics   growth & development   metabolism   MeSH
• Benzamides MeSH
• Cell Wall * metabolism   MeSH
• Gibberellins metabolism   MeSH
• Hypocotyl growth & development   genetics   metabolism   MeSH
• Indoleacetic Acids * metabolism   MeSH
• Mutation genetics   MeSH
• Pectins metabolism   MeSH
• Arabidopsis Proteins * metabolism   genetics   MeSH
• Gene Expression Regulation, Plant * MeSH
• Seedlings * genetics   growth & development   metabolism   MeSH
• Basic Helix-Loop-Helix Transcription Factors * metabolism   genetics   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Benzamides MeSH
• Gibberellins MeSH
• isoxaben MeSH Browser
• Indoleacetic Acids * MeSH
• Pectins MeSH
• PIF4 protein, Arabidopsis MeSH Browser
• Arabidopsis Proteins * MeSH
• Basic Helix-Loop-Helix Transcription Factors * MeSH

Juvenile hormone (JH) signaling is realized at the gene regulatory level by receptors of the bHLH-PAS transcription factor family. The sesquiterpenoid hormones and their synthetic mimics are agonist ligands of a unique JH receptor (JHR) protein, methoprene-tolerant (MET). Upon binding an agonist to its PAS-B cavity, MET dissociates from a cytoplasmic chaperone complex including HSP83 and concomitantly switches to a bHLH-PAS partner taiman, forming a nuclear, transcriptionally active JHR heterodimer. This course of events resembles the vertebrate aryl hydrocarbon receptor (AHR), activated by a plethora of endogenous and synthetic compounds. Like in AHR, the pliable PAS-B cavity of MET adjusts to diverse ligands and binds them through similar mechanisms. Despite recent progress, we only begin to discern agonist-induced conformational shifts within the PAS-B domain, with the ultimate goal of understanding how these localized changes stimulate the assembly of the active JHR complex and, thus, fully grasp the mechanism of JHR signaling.

• MeSH
• Juvenile Hormones * metabolism   MeSH
• Signal Transduction MeSH
• Basic Helix-Loop-Helix Transcription Factors metabolism   genetics   chemistry   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Juvenile Hormones * MeSH
• Basic Helix-Loop-Helix Transcription Factors MeSH

Hypoxia is relevant to several physiological and pathological processes and this also applies for the tooth. The adaptive response to lowering oxygen concentration is mediated by hypoxia-inducible factors (HIFs). Since HIFs were shown to participate in the promotion of angiogenesis, stem cell survival, odontoblast differentiation and dentin formation, they may play a beneficial role in the tooth reparative processes. Although some data were generated in vitro, little is known about the in vivo context of HIFs in tooth development. In order to contribute to this field, the mouse mandibular first molar was used as a model.The expression and in situ localisation of HIFs were examined at postnatal (P) days P0, P7, P14, using RT-PCR and immunostaining. The expression pattern of a broad spectrum of hypoxia-related genes was monitored by customised PCR Arrays. Metabolic aspects were evaluated by determination of the lactate level and mRNA expression of the mitochondrial marker Nd1.The results show constant high mRNA expression of Hif1a, increasing expression of Hif2a, and very low expression of Hif3a during early postnatal molar development. In the examined period the localisation of HIFs in the nuclei of odontoblasts and the subodontoblastic layer identified their presence during odontoblastic differentiation. Additionally, the lower lactate level and higher expression of mitochondrial Nd1 in advanced development points to decreasing glycolysis during differentiation. Postnatal nuclear localisation of HIFs indicates a hypoxic state in specific areas of dental pulp as oxygen demands depend on physiological events such as crown and root dentin mineralization.

• Keywords
• Dental pulp, Development, Hypoxia-inducible factors, In vivo,
• MeSH
• Hypoxia-Inducible Factor 1, alpha Subunit * metabolism   genetics   MeSH
• Metabolic Networks and Pathways MeSH
• Molar * metabolism   growth & development   MeSH
• Mice MeSH
• Odontoblasts metabolism   MeSH
• Apoptosis Regulatory Proteins MeSH
• Repressor Proteins MeSH
• Basic Helix-Loop-Helix Transcription Factors * metabolism   genetics   MeSH
• Gene Expression Regulation, Developmental MeSH
• Dental Pulp * metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• endothelial PAS domain-containing protein 1 MeSH Browser
• Hypoxia-Inducible Factor 1, alpha Subunit * MeSH
• Hif1a protein, mouse MeSH Browser
• Hif3a protein, mouse MeSH Browser
• Apoptosis Regulatory Proteins MeSH
• Repressor Proteins MeSH
• Basic Helix-Loop-Helix Transcription Factors * MeSH

BACKGROUND: The increasing ambient temperature significantly impacts plant growth, development, and reproduction. Uncovering the temperature-regulating mechanisms in plants is of high importance, for increasing our fundamental understanding of plant thermomorphogenesis, for its potential in applied science, and for aiding plant breeders in improving plant thermoresilience. Thermomorphogenesis, the developmental response to warm temperatures, has been primarily studied in seedlings and in the regulation of flowering time. PHYTOCHROME B and PHYTOCHROME-INTERACTING FACTORs (PIFs), particularly PIF4, are key components of this response. However, the thermoresponse of other adult vegetative tissues and reproductive structures has not been systematically evaluated, especially concerning the involvement of phyB and PIFs. RESULTS: We screened the temperature responses of the wild type and several phyB-PIF4 pathway Arabidopsis mutant lines in combined and integrative phenotyping platforms for root growth in soil, shoot, inflorescence, and seed. Our findings demonstrate that phyB-PIF4 is generally involved in the relay of temperature signals throughout plant development, including the reproductive stage. Furthermore, we identified correlative responses to high ambient temperature between shoot and root tissues. This integrative and automated phenotyping was complemented by monitoring the changes in transcript levels in reproductive organs. Transcriptomic profiling of the pistils from plants grown under high ambient temperature identified key elements that may provide insight into the molecular mechanisms behind temperature-induced reduced fertilization rate. These include a downregulation of auxin metabolism, upregulation of genes involved auxin signalling, miRNA156 and miRNA160 pathways, and pollen tube attractants. CONCLUSIONS: Our findings demonstrate that phyB-PIF4 involvement in the interpretation of temperature signals is pervasive throughout plant development, including processes directly linked to reproduction.

• Keywords
• Arabidopsis, Automatic phenotyping, PIF4, Pistils, Pollen tube guidance, Seeds, Thermomorphogenesis, phyB,
• MeSH
• Arabidopsis * genetics   metabolism   growth & development   physiology   MeSH
• Phenotype * MeSH
• Phytochrome B * metabolism   genetics   MeSH
• Plant Roots genetics   metabolism   growth & development   MeSH
• Flowers genetics   growth & development   MeSH
• Arabidopsis Proteins * genetics   metabolism   MeSH
• Gene Expression Regulation, Plant MeSH
• Signal Transduction MeSH
• Basic Helix-Loop-Helix Transcription Factors * genetics   metabolism   MeSH
• Hot Temperature MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Phytochrome B * MeSH
• PHYB protein, Arabidopsis MeSH Browser
• PIF4 protein, Arabidopsis MeSH Browser
• Arabidopsis Proteins * MeSH
• Basic Helix-Loop-Helix Transcription Factors * MeSH

The presence of key hypoxia regulators, namely, hypoxia-inducible factor (HIF)-1α or HIF-2α, in tumors is associated with poor patient prognosis. Hypoxia massively activates several genes, including the one encoding the BCRP transporter that proffers multidrug resistance to cancer cells through the xenobiotic efflux and is a determinant of the side population (SP) associated with cancer stem-like phenotypes. As natural medicine comes to the fore, it is instinctive to look for natural agents possessing powerful features against cancer resistance. Hypericin, a pleiotropic agent found in Hypericum plants, is a good example as it is a BCRP substrate and potential inhibitor, and an SP and HIF modulator. Here, we showed that hypericin efficiently accumulated in hypoxic cancer cells, degraded HIF-1/2α, and decreased BCRP efflux together with hypoxia, thus diminishing the SP population. On the contrary, this seemingly favorable result was accompanied by the stimulated migration of this minor population that preserved the SP phenotype. Because hypoxia unexpectedly decreased the BCRP level and SP fraction, we compared the SP and non-SP proteomes and their changes under hypoxia in the A549 cell line. We identified differences among protein groups connected to the epithelial-mesenchymal transition, although major changes were related to hypoxia, as the upregulation of many proteins, including serpin E1, PLOD2 and LOXL2, that ultimately contribute to the initiation of the metastatic cascade was detected. Altogether, this study helps in clarifying the innate and hypoxia-triggered resistance of cancer cells and highlights the ambivalent role of natural agents in the biology of these cells.

• Keywords
• Breast cancer resistance protein, ECM reorganization, Hypericin, Hypoxia, Proteomics, Side population,
• MeSH
• ATP Binding Cassette Transporter, Subfamily G, Member 2 genetics   metabolism   MeSH
• Hypoxia-Inducible Factor 1, alpha Subunit metabolism   MeSH
• Cell Hypoxia MeSH
• Hypoxia MeSH
• Humans MeSH
• Cell Line, Tumor MeSH
• Neoplasm Proteins genetics   metabolism   MeSH
• Neoplasms * metabolism   MeSH
• Gene Expression Regulation, Neoplastic MeSH
• Basic Helix-Loop-Helix Transcription Factors genetics   metabolism   MeSH
• Side-Population Cells * pathology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• ATP Binding Cassette Transporter, Subfamily G, Member 2 MeSH
• Hypoxia-Inducible Factor 1, alpha Subunit MeSH
• hypericin MeSH Browser
• Neoplasm Proteins MeSH
• Basic Helix-Loop-Helix Transcription Factors MeSH