Changes in cellular physiology and proteomic homeostasis accompanied the initiation and progression of colorectal cancer. Thus, ubiquitination represents a central regulatory mechanism in proteome dynamics. However, the complexity of the ubiquitinating network involved in carcinogenesis remains unclear. This study revealed the tumor-suppressive role of the ubiquitin ligase Cullin4A (CUL4A) in the intestine. We showed that simultaneous loss of CUL4A and hyperactivation of the Wnt pathway promotes tumor development in the distal colon. This tumor development is caused by an accumulation of the inactive SMAD3, a TGF-β pathway mediator. Depletion of CUL4A resulted in stabilization of HUWE1, which attenuated SMAD3 function. We showed a correlation between the intracellular localization of CUL4A and colorectal cancer progression, where nuclear CUL4A localization correlates with advanced colorectal cancer progression. In summary, we identified CUL4A as an important regulator of SMAD3 signal transduction competence in a HUWE1-dependent manner and demonstrated a critical role for the crosstalk between ubiquitination and the Wnt/TGF-β signaling pathways in gastrointestinal homeostasis.
- Klíčová slova
- CUL4A, Colorectal cancer, HUWE1, Ubiquitination,
- Publikační typ
- časopisecké články MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Fibrosis contributes to tissue repair, but excessive fibrosis disrupts organ function. Alagille syndrome (ALGS, caused by mutations in JAGGED1) results in liver disease and characteristic fibrosis. Here, we show that Jag1Ndr/Ndr mice, a model for ALGS, recapitulate ALGS-like fibrosis. Single-cell RNA-seq and multi-color flow cytometry of the liver revealed immature hepatocytes and paradoxically low intrahepatic T cell infiltration despite cholestasis in Jag1Ndr/Ndr mice. Thymic and splenic regulatory T cells (Tregs) were enriched and Jag1Ndr/Ndr lymphocyte immune and fibrotic capacity was tested with adoptive transfer into Rag1-/- mice, challenged with dextran sulfate sodium (DSS) or bile duct ligation (BDL). Transplanted Jag1Ndr/Ndr lymphocytes were less inflammatory with fewer activated T cells than Jag1+/+ lymphocytes in response to DSS. Cholestasis induced by BDL in Rag1-/- mice with Jag1Ndr/Ndr lymphocytes resulted in periportal Treg accumulation and three-fold less periportal fibrosis than in Rag1-/- mice with Jag1+/+ lymphocytes. Finally, the Jag1Ndr/Ndr hepatocyte expression profile and Treg overrepresentation were corroborated in patients' liver samples. Jag1-dependent hepatic and immune defects thus interact to determine the fibrotic process in ALGS.
- Klíčová slova
- Alagille syndrome, Fibrosis, Jagged1, Notch, Treg,
- MeSH
- Alagillův syndrom patologie genetika MeSH
- buněčná diferenciace * MeSH
- hepatocyty * metabolismus patologie MeSH
- jaterní cirhóza * patologie genetika MeSH
- lidé MeSH
- modely nemocí na zvířatech MeSH
- myši inbrední C57BL MeSH
- myši knockoutované MeSH
- myši MeSH
- protein jagged-1 * metabolismus genetika MeSH
- regulační T-lymfocyty imunologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- JAG1 protein, human MeSH Prohlížeč
- Jag1 protein, mouse MeSH Prohlížeč
- protein jagged-1 * MeSH
It is generally accepted that for safe use of neural interface electrodes, irreversible faradaic reactions should be avoided in favor of capacitive charge injection. However, in some cases, faradaic reactions can be desirable for controlling specific (electro)physiological outcomes or for biosensing purposes. This study aims to systematically map the basic faradaic reactions occurring at bioelectronic electrode interfaces. We analyze archetypical platinum-iridium (PtIr), the most commonly used electrode material in biomedical implants. By providing a detailed guide to these reactions and the factors that influence them, we offer a valuable resource for researchers seeking to suppress or exploit faradaic reactions in various electrode materials. We employed a combination of electrochemical techniques and direct quantification methods, including amperometric, potentiometric, and spectrophotometric assays, to measure O2, H2, pH, H2O2, Cl2/OCl-, and soluble platinum and iridium ions. We compared phosphate-buffered saline (PBS) with an unbuffered electrolyte and complex cell culture media containing proteins. Our results reveal that the "water window"─the potential range without significant water electrolysis─varies depending on the electrolyte used. In the culture medium that is rich with redox-active species, a window of potentials where no faradaic process occurs essentially does not exist. Under cathodic polarizations, significant pH increases (alkalization) were observed, while anodic water splitting competes with other processes in media, preventing prevalent acidification. We quantified the oxygen reduction reaction and accumulation of H2O2 as a byproduct. PtIr efficiently deoxygenates the electrolyte under low cathodic polarizations, generating local hypoxia. Under anodic polarizations, chloride oxidation competes with oxygen evolution, producing relatively high and cytotoxic concentrations of hypochlorite (OCl-) under certain conditions. These oxidative processes occur alongside PtIr dissolution through the formation of soluble salts. Our findings indicate that the conventional understanding of the water window is an oversimplification. Important faradaic reactions, such as oxygen reduction and chloride oxidation, occur within or near the edges of the water window. Furthermore, the definition of the water window significantly depends on the electrolyte composition, with PBS yielding different results compared with culture media.
- Klíčová slova
- bioelectronics, electrochemistry, neurostimulation, platinum electrodes, reactive chlorine species, reactive oxygen species, water window,
- Publikační typ
- časopisecké články MeSH
Intestinal epithelial cells have the capacity to upregulate MHCII molecules in response to certain epithelial-adhesive microbes, such as segmented filamentous bacteria (SFB). However, the mechanism regulating MHCII expression as well as the impact of epithelial MHCII-mediated antigen presentation on T cell responses targeting those microbes remains elusive. Here, we identify the cellular network that regulates MHCII expression on the intestinal epithelium in response to SFB. Since MHCII on the intestinal epithelium is dispensable for SFB-induced Th17 response, we explored other CD4+ T cell-based responses induced by SFB. We found that SFB drive the conversion of cognate CD4+ T cells to granzyme+ CD8α+ intraepithelial lymphocytes. These cells accumulate in small intestinal intraepithelial space in response to SFB. Yet, their accumulation is abrogated by the ablation of MHCII on the intestinal epithelium. Finally, we show that this mechanism is indispensable for the SFB-driven increase in the turnover of epithelial cells in the ileum. This study identifies a previously uncharacterized immune response to SFB, which is dependent on the epithelial MHCII function.
- MeSH
- Bacteria MeSH
- CD4-pozitivní T-lymfocyty * MeSH
- epitelové buňky MeSH
- granzymy MeSH
- prezentace antigenu * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- granzymy MeSH
Antigen-presenting cells (APCs) are master regulators of the immune response by directly interacting with T cells to orchestrate distinct functional outcomes. Several types of professional APC exist, including conventional dendritic cells, B cells and macrophages, and numerous other cell types have non-classical roles in antigen presentation, such as thymic epithelial cells, endothelial cells and granulocytes. Accumulating evidence indicates the presence of a new family of APCs marked by the lineage-specifying transcription factor retinoic acid receptor-related orphan receptor-γt (RORγt) and demonstrates that these APCs have key roles in shaping immunity, inflammation and tolerance, particularly in the context of host-microorganism interactions. These RORγt+ APCs include subsets of group 3 innate lymphoid cells, extrathymic autoimmune regulator-expressing cells and, potentially, other emerging populations. Here, we summarize the major findings that led to the discovery of these RORγt+ APCs and their associated functions. We discuss discordance in recent reports and identify gaps in our knowledge in this burgeoning field, which has tremendous potential to advance our understanding of fundamental immune concepts.
- MeSH
- antigen prezentující buňky metabolismus MeSH
- endoteliální buňky MeSH
- jaderné receptory - podrodina 1, skupina F, člen 3 * metabolismus MeSH
- lidé MeSH
- lymfocyty * MeSH
- přirozená imunita MeSH
- transportní proteiny metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- jaderné receptory - podrodina 1, skupina F, člen 3 * MeSH
- transportní proteiny MeSH
Ameloblasts are specialized epithelial cells in the jaw that have an indispensable role in tooth enamel formation-amelogenesis1. Amelogenesis depends on multiple ameloblast-derived proteins that function as a scaffold for hydroxyapatite crystals. The loss of function of ameloblast-derived proteins results in a group of rare congenital disorders called amelogenesis imperfecta2. Defects in enamel formation are also found in patients with autoimmune polyglandular syndrome type-1 (APS-1), caused by AIRE deficiency3,4, and in patients diagnosed with coeliac disease5-7. However, the underlying mechanisms remain unclear. Here we show that the vast majority of patients with APS-1 and coeliac disease develop autoantibodies (mostly of the IgA isotype) against ameloblast-specific proteins, the expression of which is induced by AIRE in the thymus. This in turn results in a breakdown of central tolerance, and subsequent generation of corresponding autoantibodies that interfere with enamel formation. However, in coeliac disease, the generation of such autoantibodies seems to be driven by a breakdown of peripheral tolerance to intestinal antigens that are also expressed in enamel tissue. Both conditions are examples of a previously unidentified type of IgA-dependent autoimmune disorder that we collectively name autoimmune amelogenesis imperfecta.
- MeSH
- ameloblasty metabolismus MeSH
- amelogenesis imperfecta * komplikace imunologie MeSH
- antigeny imunologie metabolismus MeSH
- autoimunitní polyglandulární syndromy * komplikace imunologie MeSH
- autoprotilátky * imunologie MeSH
- celiakie * komplikace imunologie MeSH
- imunoglobulin A imunologie MeSH
- lidé MeSH
- protein AIRE nedostatek MeSH
- proteiny imunologie metabolismus MeSH
- střeva imunologie metabolismus MeSH
- zubní sklovina imunologie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- AIRE protein, human MeSH Prohlížeč
- antigeny MeSH
- autoprotilátky * MeSH
- imunoglobulin A MeSH
- protein AIRE MeSH
- proteiny MeSH
Development of immunocompetent T cells in the thymus is required for effective defence against all types of pathogens, including viruses, bacteria and fungi. To this end, T cells undergo a very strict educational program in the thymus, during which both non-functional and self-reactive T cell clones are eliminated by means of positive and negative selection1.Thymic epithelial cells (TECs) have an indispensable role in these processes, and previous studies have shown the notable heterogeneity of these cells2-7. Here, using multiomic analysis, we provide further insights into the functional and developmental diversity of TECs in mice, and reveal a detailed atlas of the TEC compartment according to cell transcriptional states and chromatin landscapes. Our analysis highlights unconventional TEC subsets that are similar to functionally well-defined parenchymal populations, including endocrine cells, microfold cells and myocytes. By focusing on the endocrine and microfold TEC populations, we show that endocrine TECs require Insm1 for their development and are crucial to maintaining thymus cellularity in a ghrelin-dependent manner; by contrast, microfold TECs require Spib for their development and are essential for the generation of thymic IgA+ plasma cells. Collectively, our study reveals that medullary TECs have the potential to differentiate into various types of molecularly distinct and functionally defined cells, which not only contribute to the induction of central tolerance, but also regulate the homeostasis of other thymus-resident populations.
- MeSH
- autotolerance * imunologie fyziologie MeSH
- buněčná diferenciace MeSH
- chromatin MeSH
- DNA vazebné proteiny metabolismus MeSH
- endokrinní buňky MeSH
- epitelové buňky cytologie metabolismus MeSH
- genetická transkripce MeSH
- ghrelin MeSH
- myši MeSH
- parenchymatická tkáň MeSH
- svalové buňky MeSH
- T-lymfocyty * klasifikace cytologie imunologie MeSH
- thymus * cytologie imunologie MeSH
- transkripční faktory MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- chromatin MeSH
- DNA vazebné proteiny MeSH
- ghrelin MeSH
- Insm1 protein, mouse MeSH Prohlížeč
- Spib protein, mouse MeSH Prohlížeč
- transkripční faktory MeSH
Interleukin (IL)-17 protects epithelial barriers by inducing the secretion of antimicrobial peptides. However, the effect of IL-17 on Paneth cells (PCs), the major producers of antimicrobial peptides in the small intestine, is unclear. Here, we show that the targeted ablation of the IL-17 receptor (IL-17R) in PCs disrupts their antimicrobial functions and decreases the frequency of ileal PCs. These changes become more pronounced after colonization with IL-17 inducing segmented filamentous bacteria. Mice with PCs that lack IL-17R show an increased inflammatory transcriptional profile in the ileum along with the severity of experimentally induced ileitis. These changes are associated with a decrease in the diversity of gut microbiota that induces a severe ileum pathology upon transfer to genetically susceptible mice, which can be prevented by the systemic administration of IL-17a/f in microbiota recipients. In an exploratory analysis of a small cohort of pediatric patients with Crohn's disease, we have found that a portion of these patients exhibits a low number of lysozyme-expressing ileal PCs and a high ileitis severity score, resembling the phenotype of mice with IL-17R-deficient PCs. Our study identifies IL-17R-dependent signaling in PCs as an important mechanism that maintains ileal homeostasis through the prevention of dysbiosis.
- MeSH
- antimikrobiální peptidy MeSH
- dítě MeSH
- dysbióza mikrobiologie MeSH
- ileitida * mikrobiologie MeSH
- ileum mikrobiologie MeSH
- interleukin-17 MeSH
- lidé MeSH
- mikrobiota * MeSH
- myši MeSH
- Panethovy buňky patologie MeSH
- receptory interleukinu-17 * genetika MeSH
- zánět patologie MeSH
- zvířata MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Názvy látek
- antimikrobiální peptidy MeSH
- Il17ra protein, mouse MeSH Prohlížeč
- interleukin-17 MeSH
- receptory interleukinu-17 * MeSH
