The Transcription Factor p63 Is a Direct Effector of IL-4- and IL-13-Mediated Repression of Keratinocyte Differentiation.

Atopic Dermatitis is an inflammatory skin disease associated with broad defects in skin barrier function caused by increased levels of type-2 cytokines (IL-4 and IL-13) that repress keratinocyte (KC) differentiation. Although crucial in mediating allergic disease, the mechanisms for gene repression induced by type-2 cytokines remain unclear. In this study, we determined that gene repression requires the master regulator of the epidermal differentiation program, p63. We found that type-2 cytokine-mediated inhibition of the expression of genes involved in early KC differentiation, including keratin 1, keratin 10, and DSC-1, is reversed by p63 blockade. Type-2 cytokines, through p63, also regulate additional genes involved in KC differentiation, including CHAC-1, STC2, and CALML5. The regulation of the expression of these genes is ablated by p63 small interfering RNA as well. In addition, we found that IL-4 and IL-13 and Staphylococcus aureus lipoteichoic acid work in combination through p63 to further suppress the early KC differentiation program. Finally, we found that IL-4 and IL-13 also inhibit the activity of Notch, a transcription factor required to induce early KC differentiation. In conclusion, type-2 cytokine-mediated gene repression and blockade of KC differentiation are multifactorial, involving pathways that converge on transcription factors critical for epidermal development, p63 and Notch.

Impact of lipopolysaccharide administration on luteinizing hormone/choriogonadotropin receptor (Lhcgr) expression in mouse ovaries.

Lipopolysaccharide (LPS) is isolated from the genital tract of animals suffering from uterine damage and ovarian dysfunction. This study provides direct molecular evidence about the mechanism through which endotoxins cause reproductive disorders. Granulosa cells and ovaries were collected from immature mice treated with eCG or with eCG and LPS injection intraperitoneally. Normal large antral follicles were observed in ovaries obtained from eCG and LPS coinjected mice, and the morphology of the ovaries was similar to that observed in the control group. These antral follicles were not deemed atretic because few TUNEL-positive cells were observed. However, the granulosa cells of large antral follicles did not acquire the ability to respond to hCG stimulation. The number of ovulated oocytes was significantly lower in LPS-injected mice after superovulation compared to mice that were not exposed to LPS. The low reactivity was caused by the limited expression of the Lhcgr gene, which encodes the LH receptor in granulosa cells as well as an LPS-induced increase in the level of Dnmt1 expression. The methylation rate of the Lhcgr promoter region was significantly higher in granulosa cells obtained from the LPS treatment group compared with the control group. Together, these findings demonstrated that the decrease in the expression of Lhcgr due to LPS was a result of the epigenetic regulatory action of LPS. Our studies suggest that ovarian follicular cysts that is characterized by bacterial infection in humans and animals, is closely connected to the level of methylation of the Lhcgr promoter region.

Exposing Hidden Targets: Combining epigenetic and immunotherapy to overcome cancer resistance.

Advances in immunotherapy, most notably antibodies targeting the inhibitory immune receptors cytotoxic T-lymphocyte associated protein 4 (CTLA-4/CD152), programmed death protein 1 (PD-1/CD279) and programmed death-ligand 1 (PD-L1/B7H1/CD274) have become effective standard therapies in advanced malignancies including melanoma,1-4 merkel cell carcinoma5, urological cancers6-8, non-small cell lung cancer9-11, mis-match repair (MMR) deficient tumors12, and Hodgkin lymphoma with response rates ranging from 25 to 60% in the first and second line settings13,14. FDA approval has also been given for treatment for hepatocellular carcinoma, gastric cancer, triple negative breast cancer, cervical and head and neck cancers with response rates closer to 15 %15. Additionally, some clinical efficacy has been observed in ovarian cancer, mesothelioma, prostate cancer, diffuse large B cell lymphoma, follicular lymphoma, and both cutaneous and peripheral T-cell lymphoma. However, despite these successes, most patients will initially fail to respond to treatment and almost half of initial responders will develop secondary resistance to immunotherapy and progress. Moreover, many prevalent solid organ tumors remain resistant to immunotherapy including colorectal, pancreatic and hepatobiliary cancers. Therefore, new therapies are needed to increase both initial and durable response rates and to develop new mechanistic insights into pathways of immune resistance so that immunotherapy may become more widely available as a therapeutic option in common malignancies.

Development of a protein-based system for transient epigenetic repression of immune checkpoint molecule and enhancement of antitumour activity of natural killer cells.

BACKGROUND: Immune checkpoint blockade (ICB) therapy improved the prognosis of cancer patients, but general administration of ICBs occasionally induces side effects that include immune-related adverse events and tumour hyper-progression. Here, we established a protein-based system, by which endogenous expression of IC molecule in natural killer (NK) cells was transiently repressed on enhancement of their antitumour activity. METHODS: A protein-based genome modulator (GM) system is composed of a transcription activator-like effector (TALE), DNA methyltransferase and a newly identified potent cell-penetrating peptide with nuclear-trafficking property named NTP. TALE was designed to target the promoter region of the programmed cell death-1 (PD-1) gene. After culturing human NK cells in the presence of NTP-GM protein, we examined endogenous PD-1 expression and antitumour activity of the treated cells. RESULTS: NTP-GM protein efficiently downregulated PD-1 expression in NK cells with increased CpG DNA methylation in the promoter region. The antitumour activity of the treated NK cells was enhanced, and repeated intraperitoneal administrations of the treated NK cells attenuated tumour growth of programmed death-ligand 1-positive tumour cells in vivo. CONCLUSIONS: Because the incorporated NTP-GM protein was quickly degraded and negligible in the administered NK cells, the NTP-GM system could be an alternative option of an ICB without side effects.

An Evolutionarily Conserved Function of Polycomb Silences the MHC Class I Antigen Presentation Pathway and Enables Immune Evasion in Cancer.

Loss of MHC class I (MHC-I) antigen presentation in cancer cells can elicit immunotherapy resistance. A genome-wide CRISPR/Cas9 screen identified an evolutionarily conserved function of polycomb repressive complex 2 (PRC2) that mediates coordinated transcriptional silencing of the MHC-I antigen processing pathway (MHC-I APP), promoting evasion of T cell-mediated immunity. MHC-I APP gene promoters in MHC-I low cancers harbor bivalent activating H3K4me3 and repressive H3K27me3 histone modifications, silencing basal MHC-I expression and restricting cytokine-induced upregulation. Bivalent chromatin at MHC-I APP genes is a normal developmental process active in embryonic stem cells and maintained during neural progenitor differentiation. This physiological MHC-I silencing highlights a conserved mechanism by which cancers arising from these primitive tissues exploit PRC2 activity to enable immune evasion.

SATB1 Expression Governs Epigenetic Repression of PD-1 in Tumor-Reactive T Cells.

Despite the importance of programmed cell death-1 (PD-1) in inhibiting T cell effector activity, the mechanisms regulating its expression remain poorly defined. We found that the chromatin organizer special AT-rich sequence-binding protein-1 (Satb1) restrains PD-1 expression induced upon T cell activation by recruiting a nucleosome remodeling deacetylase (NuRD) complex to Pdcd1 regulatory regions. Satb1 deficienct T cells exhibited a 40-fold increase in PD-1 expression. Tumor-derived transforming growth factor ß (Tgf-ß) decreased Satb1 expression through binding of Smad proteins to the Satb1 promoter. Smad proteins also competed with the Satb1-NuRD complex for binding to Pdcd1 enhancers, releasing Pdcd1 expression from Satb1-mediated repression, Satb1-deficient tumor-reactive T cells lost effector activity more rapidly than wild-type lymphocytes at tumor beds expressing PD-1 ligand (CD274), and these differences were abrogated by sustained CD274 blockade. Our findings suggest that Satb1 functions to prevent premature T cell exhaustion by regulating Pdcd1 expression upon T cell activation. Dysregulation of this pathway in tumor-infiltrating T cells results in diminished anti-tumor immunity.

Luces y sombras de la inmunodeficiencia común variable / No disponible

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Epigenetic regulation analyses of FOXP3 in olive pollen allergy

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