Identifications of three novel alleles of Serrate in Drosophila.

The Notch signaling pathway, an evolutionarily highly conserved pathway, participates in various essential physiological processes in organisms. Activation of Notch signaling in the canonical manner requires the combination of ligand and receptor. There are two ligands of Notch in Drosophila: Delta (Dl) and Serrate (Ser). A mutation mf157 is identified for causing nicks of fly wings in genetic analysis from a mutant library (unpublished) that was established previously. Immunofluorescent staining illustrates that mf157 represses the expression of Cut and Wingless (Wg), the targets of Notch signaling. MARCM cloning analysis reveals that mf157 functions at the same level or the upstream of ligands of Notch in signaling sending cells. Sequencing demonstrates that mf157 is a novel allele of the Ser gene. Subsequently, mf553 and mf167 are also identified as new alleles of Ser from our library. Furthermore, the complementary assays and the examination of transcripts confirm the sequencing results. Besides, the repressed phenotypes of Notch signaling were reverted by transposon excision experiments of mf157. In conclusion, we identify three fresh alleles of Ser. Our works supply additional genetic resources for further study of functions of Ser and Notch signaling regulation.

Xiaotansanjiefang inhibits the viability of colorectal cancer cells via Jagged 1/Notch 3/Snail signaling pathway.

The purpose of this study is to explore the anti-colorectal cancer of Xiaotansanjiefang, a famous traditional Chinese medicine, and its potential anti-cancer mechanism. In this study, the HCT116 cell spheres were prepared as in vitro study model. We found the Xiaotansanjiefang medication was able to inhibit the proliferation of HCT116 cell spheres in a dose-dependent manner, especially in 3 and 6 mg/ml Xiaotansanjiefang medication treated groups. We also found the high concentration of Xiaotansanjiefang medication could suppress the migration and promote the apoptosis of HCT116 cell spheres. Moreover, we found the expression of Jagged 1, Notch 3, Snail, and Hes 1 were decreased in HCT116 cell spheres treated with Xiaotansanjiefang medication. Furthermore, the proliferation and apoptosis behaviors of HCT116 cell spheres treated with Xiaotansanjiefang medication were reversed with the addition of Jagged 1 Fc chimera protein. The expression of Jagged 1, Notch 3, Snail, and Hes 1 were also increased again in HCT116 cells treated with Xiaotansanjiefang medication plus with Jagged 1 Fc chimera protein. The presented study may provide a promising strategy to treat and prevent colorectal cancer.

Notch receptors and ligands in inflammatory arthritis - a systematic review.

BACKGROUND: Notch pathway is highly conserved across species and is involved in the regulation of cell differentiation and activity both in embryonic development and adult life. Notch signaling has an important role in the development of hematopoietic stem cells and their differentiation to committed lineages, as well as in the regulation of several non-hematopoietic cell lines. OBJECTIVE: As Notch signaling has been implicated in various inflammatory and autoimmune diseases, it is of interest to elucidate what role do Notch receptors and ligands have in inflammatory arthritides. METHODS: We performed a search on the role of Notch receptors (1-4) and Notch ligands Delta-like (DLL) 1, 3, 4 and Jagged (Jag) 1 and 2 in animal models of inflammatory arthritis and most common types of human inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis or ankylosing spondylitis). The initial search identified 135 unique articles, of which 24 were ultimately deemed relevant and included in this systematic review. RESULTS: Overall, identified articles describe roles for Notch ligands and receptors in inflammatory arthritis, with Notch activation resulting in enhanced Th1/17 polarization, osteoclast differentiation, macrophage activation and fibroblast-like synoviocyte proliferation. However, the inhibitory role of Notch signaling, especially by Jag1 is also described. CONCLUSION: There is evidence that Notch pathway activation affects multiple cell lineages present within the arthritic environment, therefore potentially acting as one of the drivers of disease pathogenesis. Since cell lineage-selective transgenic mouse models and specific Notch receptor inhibitors are becoming increasingly available, it can be expected that future research will evaluate whether Notch signaling components initiate crucial pathogenic impulses and, therefore, present viable therapeutic targets in inflammatory arthritis.

[Effect of triptolide on expressions of Notch receptors and ligands in rats with adjuvant- induced arthritis and reduced pulmonary function].

OBJECTIVE: To investigate the effects of triptolide on Notch receptor and ligand expressions in rats with adjuvant-induced arthritis (AA). METHODS: Forty rats were randomly divided into normal control (NC) group, model (MC) group, methotrexate group and triptolide groups. Rat models of AA were established by an intradermal injection of 0.1 mL Freund's complete adjuvant into the right paw. Twelve days after the injection, the rats were treated with corresponding drugs for 30 days; the rats in NC group and MC group were given saline only. Paw edema volume (E), arthritis index (AI), pulmonary function, histomorphologies, and Notch receptor/ ligand expression in the lung tissue were analyzed after the treatments. RESULTS: Compared with the NC group, E, AI, Notch3, Notch4, and Delta1 expressions in the lung tissues significantly increased while pulmonary function and pulmonary expressions of Notch1, Jagged1, and Jagged2 significantly decreased the model rats (P<0.01). Compared with the MC group, triptolide-treated rats showed significantly improved pulmonary functions, increased expressions of Notch1, Jagged1, and Jagged2 and decreased expressions of Notch3, Notch4, and Delta1 in the lungs (P<0.05, P<0.01); the therapeutic effect of triptolide was better than that of methotrexate. CONCLUSION: Triptolide can reduce inflammatory reaction and immune complex deposition to improve joint and pulmonary symptoms in rats with AA possibly by up-regulating the expressions of Notch3, Notch4, and Delta1 and down-regulating the expressions of Jagged1, Jagged2, and Notch1.

JAGGED1 gene variations in Chinese twin sisters with Alagille syndrome.

Variations in the JAGGED1 gene have been found to cause Alagille syndrome. Nevertheless, no particular hotspots in the gene have been found; any part of the entire coding regions for JAGGED1 may be involved. Twin sisters with jaundice visited our hospital and were diagnosed with Alagille syndrome. The gene variations in their JAGGED1 coding sequences were evaluated by complementary DNA sequencing. The 12-month-old twin sisters have broad foreheads, deep-set eyes, pointed chins, and triangular faces with jaundice. Clinical testing showed the presence of posterior embryotoxon, butterfly vertebrae, and atrial septal defect. Biochemical indexes showed cholestasis and liver damage. Three conserved variations were identified within exons 22 (c.2612C>G), 24 (c.2957T>A), and 26 (c.3417T>C) in the JAGGED1 coding sequence. The predicted consequences for c.2612C>G, c.2957T>A, and c.3417T>C were p.Pro871Arg, p.Leu986*, and p.Tyr1139=, respectively. The T to A change in the JAGGED1 coding sequence at 2957 will generate a stop codon and might lead to deletion of amino acid 233 at the C terminal of the JAGGED1 protein. Our data suggest that gene variations of c.2612C>G, c.2957T>A, and c.3417T>C, especially c.2957T>A, might have contributed to the pathogenesis of Alagille syndrome in these Chinese twin sisters and provided new gene evidences for Alagille syndrome.

Biological therapy induces expression changes in Notch pathway in psoriasis.

Psoriasis is a chronic inflammatory skin disease, characterized by hyperproliferation of keratinocytes and by skin infiltration of activated T cells. To date, the pathophysiology of psoriasis has not yet been fully elucidated. The Notch pathway plays a determinant role in cell fate determination, proliferation, differentiation, immune cell development and function. Many biological agents, used in the treatment of psoriasis, include TFN-α inhibitors, such as etanercept, adalimumab, and anti IL-12/IL-23 p40 antibody, such as ustekinumab. This study aimed to determine mRNA expression levels by real-time RT-PCR, and protein expression levels, analysed by Western blot and immunohistochemistry, of some components of the Notch pathway, such as NOTCH1, NOTCH2, JAGGED1, and HES1 after biological treatments in psoriatic patients. mRNA and protein levels of NOTCH1, NOTCH2, JAGGED1 and HES1 were upregulated in skin samples from untreated psoriatic patients compared with normal controls. Biological therapy showed to downregulate differently the protein expression levels of the molecules under study. Our study suggests that Notch pathway components might be a potential therapeutic target against psoriasis.

DHA suppresses chronic apoptosis in the lung caused by perinatal inflammation.

We have previously shown that an adverse perinatal environment significantly alters lung growth and development and results in persistently altered cardiopulmonary physiology in adulthood. Our model of maternal LPS treatment followed by 14 days of neonatal hyperoxia exposure causes severe pulmonary disease characterized by permanent decreases in alveolarization and diffuse interstitial fibrosis. The current investigations tested the hypothesis that dysregulation of Notch signaling pathways contributes to the permanently altered lung phenotype in our model and that the improvements we have observed previously with maternal docosahexaenoic acid (DHA) supplementation are mediated through normalization of Notch-related protein expression. Results indicated that inflammation (IL-6 levels) and oxidation (F2a-isoprostanes) persisted through 8 wk of life in mice exposed to LPS/O2 perinatally. These changes were attenuated by maternal DHA supplementation. Modest but inconsistent differences were observed in Notch-pathway proteins Jagged 1, DLL 1, PEN2, and presenilin-2. We detected substantial increases in markers of apoptosis including PARP-1, APAF-1, caspase-9, BCL2, and HMGB1, and these increases were attenuated in mice that were nursed by DHA-supplemented dams during the perinatal period. Although Notch signaling is not significantly altered at 8 wk of age in mice with perinatal exposure to LPS/O2, our findings indicate that persistent apoptosis continues to occur at 8 wk of age. We speculate that ongoing apoptosis may contribute to persistently altered lung development and may further enhance susceptibility to additional pulmonary disease. Finally, we found that maternal DHA supplementation prevented sustained inflammation, oxidation, and apoptosis in our model.

Anti-tumor effect of the extract from qingyihuaji formula on pancreatic cancer by down-regulating Notch-4 and Jagged-1.

OBJECTIVE: To investigate, in terms of Notch signaling pathway, the effect on pancreatic cancer of the extract of an anti-tumor prescription--Qingyi-huaji formula (QYHJ)--from Traditional Chinese Medicine (TCM). METHODS: Nude mice were implanted subcutaneously with human pancreatic cancer cell line SW1990 and then randomly divided into four groups: Control, QYHJ extract, Gemcitabine, and Combination of QYHJ extract and gemcitabine. Treatments were given for 21 days and tumor growth was evaluated simultaneously. Then, expression of Notch receptors (Notch-1, Notch-2, Notch-3, and Notch-4) and their Jagged ligands (Jagged-1 and Jagged-2) in dissected tumor tissue were detected by real-time quantitative reverse transcription-polymerase chain reaction and Western blot. Finally, immunohistochemistry was performed to detect CD133, a marker of pancreatic cancer stem cells (CSCs), to evaluate the impact of QYHJ extract on pancreatic CSCs. RESULTS: QYHJ extract treatment effectively inhibited the tumor growth in nude mice. The expression of both Notch-4 and Jagged-1 were decreased significantly in QYHJ treatment groups (P < 0.05), while gemcitabine alone had no significant effect in down-regulating Jagged-1 (P > 0.05). No significant difference was observed in the ex- pression of Notch-1, Notch-2, Notch-3, and Jagged-2 between three treatment groups and control group (P > 0.05). Moreover, immunohistochemical analysis showed that the number of CD133 positive cells was significantly reduced by QYHJ treatment (P < 0.05), and the combined treatment was more effective than gemcitabine alone (P < 0.05). CONCLUSION: The role of the extract in pancreatic cancer treatment was associated with down-regulation of Notch-4 and Jagged-1 in Notch signaling pathway. The extract could enhance the antitumor activity of gemcitabine and was more effective than gemcitabine in regulating Notch signaling pathway to some extent.

Effect of triptolide on expressions of Notch receptors and ligands in rats with adjuvant- induced arthritis and reduced pulmonary function / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of triptolide on Notch receptor and ligand expressions in rats with adjuvant-induced arthritis (AA).</p><p><b>METHODS</b>Forty rats were randomly divided into normal control (NC) group, model (MC) group, methotrexate group and triptolide groups. Rat models of AA were established by an intradermal injection of 0.1 mL Freund's complete adjuvant into the right paw. Twelve days after the injection, the rats were treated with corresponding drugs for 30 days; the rats in NC group and MC group were given saline only. Paw edema volume (E), arthritis index (AI), pulmonary function, histomorphologies, and Notch receptor/ ligand expression in the lung tissue were analyzed after the treatments.</p><p><b>RESULTS</b>Compared with the NC group, E, AI, Notch3, Notch4, and Delta1 expressions in the lung tissues significantly increased while pulmonary function and pulmonary expressions of Notch1, Jagged1, and Jagged2 significantly decreased the model rats (P<0.01). Compared with the MC group, triptolide-treated rats showed significantly improved pulmonary functions, increased expressions of Notch1, Jagged1, and Jagged2 and decreased expressions of Notch3, Notch4, and Delta1 in the lungs (P<0.05, P<0.01); the therapeutic effect of triptolide was better than that of methotrexate.</p><p><b>CONCLUSION</b>Triptolide can reduce inflammatory reaction and immune complex deposition to improve joint and pulmonary symptoms in rats with AA possibly by up-regulating the expressions of Notch3, Notch4, and Delta1 and down-regulating the expressions of Jagged1, Jagged2, and Notch1.</p>

[Role of Notch-Jagged/Delta signaling pathway in arthritis rats of reduced lung function induced by adjuvant].

OBJECTIVE: To observe the changes of pulmonary function and Notch signaling pathway of lung tissues in adjuvant-induced arthritis rats, and to investigate the mechanism of reduced lung function. METHODS: A total of 30 rats were randomly divided into a normal group and a model group. Rats in the model group were induced to establish the adjuvant arthritis AA model by intradermally injecting 0.1 mL Freund's complete adjuvant into the right paw. After 30 days, we observed the paw edema volume, arthritis index, pulmonary function, histomorphology, and Notch receptor/ligand of the lung tissue. RESULTS: Compared with the normal group, the paw edema volume, arthritis index, average expiratory flow within 0.3 s (FEV0.3/FVC), and the level of Notch3, Notch4 and Jagged2 of the lung tissue in the model group was significantly increased, while maximum expiratory flow at 50% of vital capacity (FEF50), maximum expiratory flow at 75% of vital capacity (FEF75), forced expiratory flow (PEF) and the expression of Notch1 of Jagged1 and Delta1 in the lung were significantly decreased (P<0.05, P<0.01). There were significant positive correlations between FEV0.3/FVC and Notch4. FEV0.3/FVC, FEF25, FEF50 and Notch3, Delta1 were negatively correlated, respectively (P<0.05, P<0.01). CONCLUSION: While arthritis occurs in AA rats, pulmonary function declines and significantly correlates with the expression of Notch receptor/ligand. The deposition of immune complex in the lung after the injection of CFA activates the Notch signaling pathway, and results in further decline of pulmonary function by signaling cascades.

Notch signaling regulates ovarian follicle formation and coordinates follicular growth.

Ovarian follicles form through a process in which somatic pregranulosa cells encapsulate individual germ cells from germ cell syncytia. Complementary expression of the Notch ligand, Jagged1, in germ cells and the Notch receptor, Notch2, in pregranulosa cells suggests a role for Notch signaling in mediating cellular interactions during follicle assembly. Using a Notch reporter mouse, we demonstrate that Notch signaling is active within somatic cells of the embryonic ovary, and these cells undergo dramatic reorganization during follicle histogenesis. This coincides with a significant increase in the expression of the ligands, Jagged1 and Jagged2; the receptor, Notch2; and the target genes, Hes1 and Hey2. Histological examination of ovaries from mice with conditional deletion of Jagged1 within germ cells (J1 knockout [J1KO]) or Notch2 within granulosa cells (N2 knockout [N2KO]) reveals changes in follicle dynamics, including perturbations in the primordial follicle pool and antral follicle development. J1KO and N2KO ovaries also contain multi-oocytic follicles, which represent a failure to resolve germ cell syncytia, and follicles with enlarged oocytes but lacking somatic cell growth, signifying a potential role of Notch signaling in follicle activation and the coordination of follicle development. We also observed decreased cell proliferation and increased apoptosis in the somatic cells of both conditional knockout lines. As a consequence of these defects, J1KO female mice are subfertile; however, N2KO female mice remain fertile. This study demonstrates important functions for Jagged1 and Notch2 in the resolution of germ cell syncytia and the coordination of somatic and germ cell growth within follicles of the mouse ovary.

Role of Notch-Jagged/Delta signaling pathway in arthritis rats of reduced lung function induced by adjuvant / 中南大学学报(医学版)

OBJECTIVE@#To observe the changes of pulmonary function and Notch signaling pathway of lung tissues in adjuvant-induced arthritis rats, and to investigate the mechanism of reduced lung function.@*METHODS@#A total of 30 rats were randomly divided into a normal group and a model group. Rats in the model group were induced to establish the adjuvant arthritis AA model by intradermally injecting 0.1 mL Freund's complete adjuvant into the right paw. After 30 days, we observed the paw edema volume, arthritis index, pulmonary function, histomorphology, and Notch receptor/ligand of the lung tissue.@*RESULTS@#Compared with the normal group, the paw edema volume, arthritis index, average expiratory flow within 0.3 s (FEV0.3/FVC), and the level of Notch3, Notch4 and Jagged2 of the lung tissue in the model group was significantly increased, while maximum expiratory flow at 50% of vital capacity (FEF50), maximum expiratory flow at 75% of vital capacity (FEF75), forced expiratory flow (PEF) and the expression of Notch1 of Jagged1 and Delta1 in the lung were significantly decreased (P<0.05, P<0.01). There were significant positive correlations between FEV0.3/FVC and Notch4. FEV0.3/FVC, FEF25, FEF50 and Notch3, Delta1 were negatively correlated, respectively (P<0.05, P<0.01).@*CONCLUSION@#While arthritis occurs in AA rats, pulmonary function declines and significantly correlates with the expression of Notch receptor/ligand. The deposition of immune complex in the lung after the injection of CFA activates the Notch signaling pathway, and results in further decline of pulmonary function by signaling cascades.

bFGF and JAGGED1 regulate alkaline phosphatase expression and mineralization in dental tissue-derived mesenchymal stem cells.

Basic fibroblast growth factor (bFGF) and Notch signaling play critical roles in various cell behaviors. Here, we investigated the influence of bFGF and Notch signaling in alkaline phosphatase (ALP) expression and mineralization process in human periodontal ligament-derived mesenchymal stem cells (PDLSCs) and stem cells isolated from human exfoliated deciduous teeth (SHEDs). PDLSCs and SHEDs were cultured in osteogenic medium supplemented with bFGF or on the immobilized Notch ligands, JAGGED1. The ALP mRNA and protein expression were measured by quantitative reverse transcriptase polymerase chain reaction and enzymatic activity assay, respectively. Mineral deposition was determined using alizarin red S staining. The results showed that the addition of bFGF resulted in the decrease of ALP mRNA expression and enzymatic activity. In addition, the attenuation of mineralization was noted. These phenomenons were blocked by the addition of a fibroblast growth factor receptor inhibitor (SU5402) or a MEK inhibitor (PD98059). Interestingly, bFGF supplementation also decreased the Notch signaling component mRNA levels. Thus, to evaluate effect of Notch signaling in mineralization process, PDLSCs and SHEDs were exposed to JAGGED1 modified surface. The ALP mRNA and protein expression were significantly upregulated and the mineral deposition was markedly increased. These results could be reversed by the addition of a γ-secretase inhibitor. In addition, bFGF could attenuate the Notch-signaling-induced mineralization in both PDLSCs and SHEDs. These results suggest that mineralization was enhanced by Notch signaling but attenuated by bFGF signaling. This knowledge can be further utilized to control PDLSCs and SHEDs mineralization for tissue regeneration purpose.

Endothelio-mesenchymal interaction controls runx1 expression and modulates the notch pathway to initiate aortic hematopoiesis.

Hematopoietic stem cells (HSCs) are produced by a small cohort of hemogenic endothelial cells (ECs) during development through the formation of intra-aortic hematopoietic cell (HC) clusters. The Runx1 transcription factor plays a key role in the EC-to-HC and -HSC transition. We show that Runx1 expression in hemogenic ECs and the subsequent initiation of HC formation are tightly controlled by the subaortic mesenchyme, although the mesenchyme is not a source of HCs. Runx1 and Notch signaling are involved in this process, with Notch signaling decreasing with time in HCs. Inhibiting Notch signaling readily increases HC production in mouse and chicken embryos. In the mouse, however, this increase is transient. Collectively, we show complementary roles of hemogenic ECs and mesenchymal compartments in triggering aortic hematopoiesis. The subaortic mesenchyme induces Runx1 expression in hemogenic-primed ECs and collaborates with Notch dynamics to control aortic hematopoiesis.

High throughput kinase inhibitor screens reveal TRB3 and MAPK-ERK/TGFß pathways as fundamental Notch regulators in breast cancer.

Expression of the Notch ligand Jagged 1 (JAG1) and Notch activation promote poor-prognosis in breast cancer. We used high throughput screens to identify elements responsible for Notch activation in this context. Chemical kinase inhibitor and kinase-specific small interfering RNA libraries were screened in a breast cancer cell line engineered to report Notch. Pathway analyses revealed MAPK-ERK signaling to be the predominant JAG1/Notch regulator and this was supported by gene set enrichment analyses in 51 breast cancer cell lines. In accordance with the chemical screen, kinome small interfering RNA high throughput screens identified Tribbles homolog 3 (TRB3), a known regulator of MAPK-ERK, among the most significant hits. We demonstrate that TRB3 is a master regulator of Notch through the MAPK-ERK and TGFß pathways. Complementary in vitro and in vivo studies underscore the importance of TRB3 for tumor growth. These data demonstrate a dominant role for TRB3 and MAPK-ERK/TGFß pathways as Notch regulators in breast cancer, establishing TRB3 as a potential therapeutic target.

Fast-forward genetics identifies plant CPL phosphatases as regulators of miRNA processing factor HYL1.

MicroRNAs (miRNAs) are processed from primary transcripts that contain partially self-complementary foldbacks. As in animals, the core microprocessor in plants is a Dicer protein, DICER-LIKE1 (DCL1). Processing accuracy and strand selection is greatly enhanced through the RNA binding protein HYPONASTIC LEAVES 1 (HYL1) and the zinc finger protein SERRATE (SE). We have combined a luciferase-based genetic screen with whole-genome sequencing for rapid identification of new regulators of miRNA biogenesis and action. Among the first six mutants analyzed were three alleles of C-TERMINAL DOMAIN PHOSPHATASE-LIKE 1 (CPL1)/FIERY2 (FRY2). In the miRNA processing complex, SE functions as a scaffold to mediate CPL1 interaction with HYL1, which needs to be dephosphorylated for optimal activity. In the absence of CPL1, HYL1 dephosphorylation and hence accurate processing and strand selection from miRNA duplexes are compromised. Our findings thus define a new regulatory step in plant miRNA biogenesis.

Differential regulation of osteoclastogenesis by Notch2/Delta-like 1 and Notch1/Jagged1 axes.

INTRODUCTION: Osteoclastogenesis plays an important role in the bone erosion of rheumatoid arthritis (RA). Recently, Notch receptors have been implicated in the development of osteoclasts. However, the responsible Notch ligands have not been identified yet. This study was undertaken to determine the role of individual Notch receptors and ligands in osteoclastogenesis. METHODS: Mouse bone marrow-derived macrophages or human peripheral blood monocytes were used as osteoclast precursors and cultured with receptor activator of nuclear factor-kappaB ligand (RANKL) and macrophage-colony stimulating factor (M-CSF) to induce osteoclasts. Osteoclasts were detected by tartrate-resistant acid phosphatase (TRAP) staining. K/BxN serum-induced arthritic mice and ovariectomized mice were treated with anti-mouse Delta-like 1 (Dll1) blocking monoclonal antibody (mAb). RESULTS: Blockade of a Notch ligand Dll1 with mAb inhibited osteoclastogenesis and, conversely, immobilized Dll1-Fc fusion protein enhanced it in both mice and humans. In contrast, blockade of a Notch ligand Jagged1 enhanced osteoclastogenesis and immobilized Jagged1-Fc suppressed it. Enhancement of osteoclastogenesis by agonistic anti-Notch2 mAb suggested that Dll1 promoted osteoclastogenesis via Notch2, while suppression by agonistic anti-Notch1 mAb suggested that Jagged1 suppressed osteoclastogenesis via Notch1. Inhibition of Notch signaling by a gamma-secretase inhibitor suppressed osteoclastogenesis, implying that Notch2/Dll1-mediated enhancement was dominant. Actually, blockade of Dll1 ameliorated arthritis induced by K/BxN serum transfer, reduced the number of osteoclasts in the affected joints and suppressed ovariectomy-induced bone loss. CONCLUSIONS: The differential regulation of osteoclastogenesis by Notch2/Dll1 and Notch1/Jagged1 axes may be a novel target for amelioration of bone erosion in RA patients.

Notch-ligand expression by NALT dendritic cells regulates mucosal Th1- and Th2-type responses.

Our previous studies showed that an adenovirus (Ad) serotype 5 vector expressing Flt3 ligand (Ad-FL) as nasal adjuvant activates CD11c(+) dendritic cells (DCs) for the enhancement of antigen (Ag)-specific IgA antibody (Ab) responses. In this study, we examined the molecular mechanism for activation of CD11c(+) DCs and their roles in induction of Ag-specific Th1- and Th2-cell responses. Ad-FL activated CD11c(+) DCs expressed increased levels of the Notch ligand (L)-expression and specific mRNA. When CD11c(+) DCs from various mucosal and systemic lymphoid tissues of mice given nasal OVA plus Ad-FL were cultured with CD4(+) T cells isolated from non-immunized OVA TCR-transgenic (OT II) mice, significantly increased levels of T cell proliferative responses were noted. Furthermore, Ad-FL activated DCs induced IFN-γ, IL-2 and IL-4 producing CD4(+) T cells. Of importance, these APC functions by Ad-FL activated DCs were down-regulated by blocking Notch-Notch-L pathway. These results show that Ad-FL induces CD11c(+) DCs to the express Notch-ligands and these activated DCs regulate the induction of Ag-specific Th1- and Th2-type cytokine responses.

Opposing interactions between homothorax and Lobe define the ventral eye margin of Drosophila eye.

Patterning in multi-cellular organisms involves progressive restriction of cell fates by generation of boundaries to divide an organ primordium into smaller fields. We have employed the Drosophila eye model to understand the genetic circuitry responsible for defining the boundary between the eye and the head cuticle on the ventral margin. The default state of the early eye is ventral and depends on the function of Lobe (L) and the Notch ligand Serrate (Ser). We identified homothorax (hth) as a strong enhancer of the L mutant phenotype of loss of ventral eye. Hth is a MEIS class gene with a highly conserved Meis-Hth (MH) domain and a homeodomain (HD). Hth is known to bind Extradenticle (Exd) via its MH domain for its nuclear translocation. Loss-of-function of hth, a negative regulator of eye, results in ectopic ventral eye enlargements. This phenotype is complementary to the L mutant phenotype of loss-of-ventral eye. However, if L and hth interact during ventral eye development remains unknown. Here we show that (i) L acts antagonistically to hth, (ii) Hth is upregulated in the L mutant background, and (iii) MH domain of Hth is required for its genetic interaction with L, while its homeodomain is not, (iv) in L mutant background ventral eye suppression function of Hth involves novel MH domain-dependent factor(s), and (v) nuclear localization of Exd is not sufficient to mediate the Hth function in the L mutant background. Further, Exd is not a critical rate-limiting factor for the Hth function. Thus, optimum levels of L and Hth are required to define the boundary between the developing eye and head cuticle on the ventral margin.

Epiplakin1 is expressed in the cholangiocyte lineage cells in normal liver and adult progenitor cells in injured liver.

We have previously identified Epiplakin1 (Eppk1) as a gene expressed in pancreatic progenitor cells. Here we studied the expression of Eppk1 in developing and regenerating livers in mice. Eppk1 is initially expressed in the early bipotential hepatoblasts and is later confined to the cholangiocytes. After birth, Eppk1 is expressed in the bile duct. In the livers of mice fed with a choline-deficient ethionine-supplemented (CDE) diet, Eppk1-positive cells dramatically increase in number. The Eppk1-positive cells express A6, thereby indicating that they are hepatic progenitor cells. Other cholangiocyte markers, such as Cytokeratins, E-cadherin, osteopontin and Sox9, are also co-expressed in the hepatic progenitor cells. Some of the Eppk1-positive cells express PCNA, a proliferation marker, thereby suggesting their identities as transient amplifying cells. In conclusion, we have shown that Eppk1 serves as a useful marker for detecting the hepatic progenitor population in the developing and adult liver. The use of Eppk1 as a marker will facilitate studies of mouse hepatic progenitor cells.