Jagged1-Notch1 Signaling Pathway Induces M1 Microglia to Disrupt the Barrier Function of Retinal Microvascular Endothelial Cells

PURPOSE

Microglia-related inflammation is closely linked to the pathogenesis of retinal diseases. The primary objective of this research was to investigate the impact and mechanism of M1 phenotype microglia on the barrier function of retina microvascular endothelial cells.

METHODS

Quantitative polymerase chain reactions and western blot techniques were utilized to analysis the mRNA and protein expressions of M1 and M2 markers of human microglial clone 3 cell line (HMC3), as well as the levels of Notch ligands and receptors under the intervention of lipopolysaccharide (LPS) or interleukin (IL)-4. ELISA was utilized to detect the pro-inflammatory and anti-inflammatory cytokines from HMC3 cells. The cellular tight junction and apoptosis of human retinal microvascular endothelial cells (HRMECs) were assessed by western blot and fluorescein isothiocyanate-dextran permeability assay. The inhibitors of Notch1 and RNA interference (RNAi) targeting Jagged1 were used to assess their contribution to the barrier function of vascular endothelial cells.

RESULTS

Inducible nitric oxide synthase (iNOS) and IL-1β were considerably elevated in LPS-treated HMC3, while CD206 and Arg-1 markedly elevated under IL-4 stimulation. The conditioned medium derived from LPS-treated HMC3 cells promoted permeability, diminished the expression of zonula occludens-1 and Occludin, and elevated the expression of Cleaved caspase-3 in HRMECs. RNAi targeting Jagged1 or Notch1 inhibitor could block M1 HMC3 polarization and maintain barrier function of HRMECs.

CONCLUSION

Our findings suggest that Jagged1-Notch1 signaling pathway induces M1 microglial cells to disrupt the barrier function of HRMECs, which may lead to retinal diseases.

β-cell Jagged1 is sufficient but not necessary for islet Notch activity and insulin secretory defects in obese mice

OBJECTIVE

Notch signaling, re-activated in β cells from obese mice and causal to β cell dysfunction, is determined in part by transmembrane ligand availability in a neighboring cell. We hypothesized that β cell expression of Jagged1 determines the maladaptive Notch response and resultant insulin secretory defects in obese mice.

METHODS

We assessed expression of Notch pathway components in high-fat diet-fed (HFD) or leptin receptor-deficient (db/db) mice, and performed single-cell RNA sequencing (scRNA-Seq) in islets from patients with and without type 2 diabetes (T2D). We generated and performed glucose tolerance testing in inducible, β cell-specific Jagged1 gain-of- and loss-of-function mice. We also tested effects of monoclonal neutralizing antibodies to Jagged1 in glucose-stimulated insulin secretion (GSIS) assays in isolated islets.

RESULTS

Jag1 was the only Notch ligand that tracked with increased Notch activity in HFD-fed and db/db mice, as well as in metabolically-inflexible β cells enriched in patients with T2D. Neutralizing antibodies to block Jagged1 in islets isolated from HFD-fed and db/db mice potentiated GSIS ex vivo. To demonstrate if β cell Jagged1 is sufficient to cause glucose tolerance in vivo, we generated inducible β cell-specific Jag1 transgenic (β-Jag1TG) and loss-of-function (iβ-Jag1KO) mice. While forced Jagged1 impaired glucose intolerance due to reduced GSIS, loss of β cell Jagged1 did not protect against HFD-induced insulin secretory defects.

CONCLUSIONS

Jagged1 is increased in islets from obese mice and in patients with T2D, and neutralizing Jagged1 antibodies lead to improved GSIS, suggesting that inhibition of Jagged1-Notch signaling may have therapeutic benefit. However, genetic loss-of-function experiments suggest that β cells are not a likely source of the Jagged1 signal.

Cancer-associated fibroblasts-induced remodeling of tumor immune microenvironment via Jagged1 in glioma

Tumor immunosuppression are prominent characteristics of brain glioma. Current standard modality including surgical resection and chemoradiotherapy do not significantly improve clinical outcomes. Cancer-associated fibroblasts (CAFs) that regard as important stromal cells in tumor microenvironment have been confirmed to play crucial roles in tumor development. However, the effects of CAFs on tumor immunosuppression in glioma are not well expounded. In this study, we report that CAFs contributes to the formation of glioma immunosuppressive microenvironment. Specifically, we found that glioma-derived Jagged1 enhanced the proliferation and PD-L1 expression of CAFs in vitro. Importantly, we discovered that Notch1, c-Myc and PD-L1 expression were significantly increased in high Jagged1-expressing gliomas, moreover, we further confirmed that Notch1 and PD-L1 expression located on the CAFs in glioma tissues. We also found that glioma-derived Jagged1 promotes the increase of tumor-infiltrating macrophages, M2 macrophages and Foxp3 Treg cells, as well as no significance of M1 macrophages and CD8+ T cells, indicating potential immunosuppression. This study opens up novel therapeutic strategies reversing CAF immunosuppression for gliomas.

Sacubitril/valsartan inhibits the proliferation of vascular smooth muscle cells through notch signaling and ERK1/2 pathway

AIMS

To explore the role and mechanism of Notch signaling and ERK1/2 pathway in the inhibitory effect of sacubitril/valsartan on the proliferation of vascular smooth muscle cells (VSMCs).

MAIN METHODS

Human aortic vascular smooth muscle cells (HA-VSMCs) were cultured in vitro. The proliferating VSMCs were divided into three groups as control group, Ang II group and Ang II + sacubitril/valsartan group. Cell proliferation and migration were detected by CCK8 and scratch test respectively. The mRNA and protein expression of PCNA, MMP-9, Notch1 and Jagged-1 were detected by qRT-PCR and Western blot respectively. The p-ERK1/2 expression was detected by Western blot.

KEY FINDINGS

Compared with the control group, proliferation and migration of VSMCs and the expression of PCNA, MMP-9, Notch1, Jagged-1 and p-ERK1/2 was increased in Ang II group. Sacubitril/valsartan significantly reduced the proliferation and migration. Additionally, pretreatment with sacubitril/valsartan reduced the PCNA, MMP-9, Notch1, Jagged-1 and p-ERK1/2 expression.

Aberrant expression of PELI1 caused by Jagged1 accelerates the malignant phenotype of pancreatic cancer

Pancreatic cancer is one of the most aggressive cancers. PELI1 has been reported to promote cell survival and proliferation in multiple cancers. As of now, the role of PELI1 in pancreatic cancer is largely unknown. Here, we found that the PELI1 mRNA was higher expressed in pancreatic tumor tissues than in adjacent normal tissues, and the high PELI1 level in pancreatic cancer patients had a short survival time compared with the low level. Moreover, the results showed that PELI1 promoted cell proliferation, migration, and invasion, and inhibited apoptosis in vitro. Xenograft tumor experiments were used to determine the biological function of PELI1, and the results showed that PELI1 promoted tumor growth in vivo. Additionally, we found that Jagged1 activated PELI1 transcription in pancreatic cancer cells. To sum up, our results show that PELI1 affects the malignant phenotype of pancreatic cancer.

[High homocysteine level promotes autophagy and apoptosis of mouse hippocampal HT22 cells through the Notch1/Hes1 signaling pathway]

OBJECTIVE

To explore the mechanism of neuronal injury caused by hyperhomocysteinemia.

METHODS

Mouse hippocampal HT22 cells were treated with homocysteine (Hcy, 100 μmol/L), Hcy+folic acid+vitamin B12 (100+fv group) or folic acid+vitamin B12 (0+fv group), and the changes in cell autophagy and apoptosis were detected using transmission electron microscope (TEM) and flow cytometry. The expressions of Hes1, Hes5, Notch1, Jagged1, Bcl-2, Bax, P62 and LC3 in the treated cells were detected with Western blotting and real-time PCR.

RESULTS

Treatment with Hcy for 48 h significantly increased the number of dead cells in HT22 cell cultures. Flow cytometry showed that the percentage of apoptotic cells was significantly higher in cells treated with Hcy alone than in other treatment groups (P<0.05). TEM revealed obvious mitochondrial swelling and vacuolation and increased autophagy in Hcy-treated cells. Western blotting showed that the Bax/Bcl-2 ratio was significantly higher in Hcy-treated cells than in the blank control cells and cells in 100+fv group (P<0.05). The Hcy-treated cells showed a significantly lower relative expression of P62 than the blank control cells (P<0.05), a higher LC3II/LC3I ratio than the cells in the blank control and 100+fv groups (P<0.05), and lower expressions of HES1, HES5, Notch1 and Jagged1 proteins than the blank control cells (P<0.05). Interference with Hes1 siRNA significantly lowered the expression levels of Hes1 and Jagged1 without obviously affecting Notch1 expression in HT22 cells (P>0.05).

CONCLUSION

High Hcy levels promote autophagy and apoptosis and down-regulate Hes1 and Jagged1 expressions in HT22 cells.

MicroRNA miR-214-5p induces senescence of microvascular endothelial cells by targeting the JAG1/Notch signaling pathway

During cellular senescence, irreversible cell cycle arrest is accompanied by morphological and genetic alterations. MicroRNAs (miRNAs) play a critical role in regulating senescence by modulating the abundance of crucial senescence regulatory proteins. Therefore, to identify novel senescence-associated miRNAs, we analyzed differentially expressed miRNAs in microvascular endothelial cells (MVEC). Among the 80 differentially expressed miRNAs in replicative senescent MVECs, 16 miRNAs of unknown gene ontology were used in the senescence-associated β-galactosidase assay. Thus, we identified miR-214-5p as having high senescence-inducing activity, inhibiting the proliferation and angiogenesis activity of MVECs. To reveal the senescence-regulating mechanism of miR-214-5p, we searched for target genes through sequence- and literature-based analysis. Molecular manipulation of miR-214-5p demonstrated that miR-214-5p regulated the expression and function of Jagged 1 (JAG1) in senescent MVECs. Silencing JAG1 or downstream genes of JAG1-Notch signaling, accelerated the senescence of MVECs. Additionally, ectopic overexpression of JAG1 reversed the senescence-inducing activity of miR-214-5p. In conclusion, we identified miR-214-5p as a senescence-associated miRNA. Targeting miR-214-5p may be a potential strategy to delay vascular aging and overcome the detrimental effects of senescence and age-related diseases.

YY1/miR-140-5p/Jagged1/Notch axis mediates cartilage progenitor/stem cells fate reprogramming in knee osteoarthritis

Osteoarthritis is a multifactorial disease characterized by cartilage degeneration, while cartilage progenitor/stem cells (CPCs) are responsible for endogenous cartilage repair. However, the relevant regulatory mechanisms of CPCs fate reprogramming in OA are rarely reported. Recently, we observed fate disorders in OA CPCs and found that microRNA-140-5p (miR-140-5p) protects CPCs from fate changes in OA. This study further mechanistically investigated the upstream regulator and downstream effectors of miR-140-5p in OA CPCs fate reprogramming. As a result, luciferase reporter assay and validation assays revealed that miR-140-5p targets Jagged1 and inhibits Notch signaling in human CPCs, and the loss-/gain-of-function experiments and rescue assays discovered that miR-140-5p improves OA CPCs fate, but this effect can be counteracted by Jagged1. Moreover, increased transcription factor Ying Yang 1 (YY1) was associated with OA progression, and YY1 could disturb CPCs fate via transcriptionally repressing miR-140-5p and enhancing the Jagged1/Notch signaling. Finally, the relevant changes and mechanisms of YY1, miR-140-5p, and Jagged1/Notch signaling in OA CPCs fate reprogramming were validated in rats. Conclusively, this study identified a novel YY1/miR-140-5p/Jagged1/Notch signaling axis that mediates OA CPCs fate reprogramming, wherein YY1 and Jagged1/Notch signaling exhibits an OA-stimulative role, and miR-140-5p plays an OA-protective effect, providing attractive targets for OA therapeutics.

APEX1 predicts poor prognosis of gallbladder cancer and affects biological properties of CD133+ GBC-SD cells via upregulating Jagged1

Although APEX1 is associated with the tumorigenesis and progression of some human cancer types, the function of APEX1 in gallbladder cancer (GBC) is unclear. In this study, we found that APEX1 expression is up-regulated in GBC tissues, and APEX1 positive expression is related to aggressive clinicopathological features and poor prognosis of GBC. APEX1 was an independent risk factor of GBC prognosis, and presented some pathological diagnostic significance in GBC. Furthermore, APEX1 was overexpressed in CD133⁺ GBC-SD cells in comparison with GBC-SD cells. APEX1 knockdown increased the sensitivity of CD133⁺ GBC-SD cells to 5-Fluorouracil via facilitating cell necrosis and apoptosis. APEX1 knockdown in CD133⁺ GBC-SD cells dramatically inhibited cell proliferation, migration, and invasion, and promoted cell apoptosis in vitro. APEX1 knockdown in CD133⁺ GBC-SD cells accelerated tumor growth in the xenograft models. Mechanistically, APEX1 affected these malignant properties via upregulating Jagged1 in CD133⁺ GBC-SD cells. Thus, APEX1 is a promising prognostic biomarker, and a potential therapeutic target for GBC.

Notch Signaling Pathway in Tooth Shape Variations throughout Evolution

Evolutionary changes in vertebrates are linked to genetic alterations that often affect tooth crown shape, which is a criterion of speciation events. The Notch pathway is highly conserved between species and controls morphogenetic processes in most developing organs, including teeth. Epithelial loss of the Notch-ligand Jagged1 in developing mouse molars affects the location, size and interconnections of their cusps that lead to minor tooth crown shape modifications convergent to those observed along Muridae evolution. RNA sequencing analysis revealed that these alterations are due to the modulation of more than 2000 genes and that Notch signaling is a hub for significant morphogenetic networks, such as Wnts and Fibroblast Growth Factors. The modeling of these tooth crown changes in mutant mice, via a three-dimensional metamorphosis approach, allowed prediction of how Jagged1-associated mutations in humans could affect the morphology of their teeth. These results shed new light on Notch/Jagged1-mediated signaling as one of the crucial components for dental variations in evolution.

miR-140-5p protects cartilage progenitor/stem cells from fate changes in knee osteoarthritis

Cartilage progenitor/stem cells (CPCs) are promising seed cells for cartilage regeneration, but their fate changes and regulatory mechanisms in osteoarthritis (OA) pathogenesis remain unclear. This study aimed to investigate the role and potential mechanism of the microRNA-140-5p (miR-140-5p), whose protective role in knee OA has been confirmed by our previous studies, in OA CPCs fate reprogramming. Firstly, the normal and OA CPCs were isolated, and the fate indicators, miR-140-5p, Jagged1, and Notch signals were detected and analyzed. Then, the effect of miR-140-5p and the Notch pathway on CPCs fate reprogramming and miR-140-5p on Jagged1/Notch signaling was investigated in IL-1β-induced chondrocytes in vitro. Finally, the effect of miR-140-5p on OA CPCs fate reprogramming and the potential mechanisms were validated in OA rats. As a result, CPCs percentage was increased in the mild OA cartilage-derived total chondrocytes while decreased in the advanced OA group. Significant fate changes (including reduced cell viability, migration, chondrogenesis, and increased apoptosis), increased Jagged1 and Notch signals, and reduced miR-140-5p were observed in OA CPCs and associated with OA progression. IL-1β induced OA-like changes in CPCs fate, which could be exacerbated by miR-140-5p inhibitor while alleviated by DAPT (a specific Notch inhibitor) and miR-140-5p mimic. Finally, the in vitro phenomenal and mechanistic findings were validated in OA rats. Overall, miR-140-5p protects CPCs from fate changes via inhibiting Jagged1/Notch signaling in knee OA, providing attractive targets for OA therapeutics.

Sex differences and risk factors for bleeding in Alagille syndrome

Spontaneous bleeds are a leading cause of death in the pediatric JAG1-related liver disease Alagille syndrome (ALGS). We asked whether there are sex differences in bleeding events in patients, whether Jag1^Ndr/Ndr mice display bleeds or vascular defects, and whether discovered vascular pathology can be confirmed in patients non-invasively. We performed a systematic review of patients with ALGS and vascular events following PRISMA guidelines, in the context of patient sex, and found significantly more girls than boys reported with spontaneous intracranial hemorrhage. We investigated vascular development, homeostasis, and bleeding in Jag1^Ndr/Ndr mice, using retina as a model. Jag1^Ndr/Ndr mice displayed sporadic brain bleeds, a thin skull, tortuous blood vessels, sparse arterial smooth muscle cell coverage in multiple organs, which could be aggravated by hypertension, and sex-specific venous defects. Importantly, we demonstrated that retinographs from patients display similar characteristics with significantly increased vascular tortuosity. In conclusion, there are clinically important sex differences in vascular disease in ALGS, and retinography allows non-invasive vascular analysis in patients. Finally, Jag1^Ndr/Ndr mice represent a new model for vascular compromise in ALGS.

Notch signaling activation contributes to paclitaxel-induced neuropathic pain via activation of A1 astrocytes

Paclitaxel-induced neuropathic pain (PINP) is a progressive and refractory side effect of chemotherapy with few effective treatments at present. It is well-established that astrocytes activation contributes to the development of PINP. Recent reports showed astrocytes can be divided into A1 and A2 phenotypes. However, whether the transformation of astrocytes participates in PINP and the underlying mechanisms remain unknown. As Notch signaling pathway have shown to be involved in neuropathic pain, we aimed to investigate the relationship between Notch signaling pathway and A1 astrocytes in PINP. Herein we found that both A1 astrocytes and Notch signaling were markedly activated in the spinal cord of PINP rats and the downstream molecules of Notch signaling were colocalized with A1 astrocytes. DAPT (an inhibitor of Notch signaling) not only suppressed the mechanical allodynia of PINP rats, but also inhibited the activation of Notch signaling pathway and A1 astrocytes. Furthermore, Jagged1 (a ligand of Notch1 receptors) dose-dependently induced mechanical hyperalgesia in naïve rats and simultaneously led to Notch signaling activation and A1 astrocytes transformation, all of which were inhibited by DAPT. Taken together, these results demonstrate Notch signaling activation contributes to PINP via A1 astrocytes activation, which provides a promising therapeutic target for PINP.

Notch1 activation of Jagged1 contributes to differentiation of mesenchymal stem cells into endothelial cells under cigarette smoke extract exposure

Background

Mesenchymal stem cells (MSCs) have shown therapeutic potential for engraftment to, differentiation into, endothelial cells (ECs). However, low-efficiency yields hinder their use as ECs for therapeutic vascularization.

Methods

The Notch1 signaling pathway is key to optimal pulmonary development. Recent evidence has shown that this pathway participated in angiogenesis. Herein, we found that in MSCs, Jagged1 was a target for Notch 1, resulting in a positive feedback loop that propagated a wave of ECs differentiation.

Results

In vitro, Jagged1 was found to be activated by Notch1 in MSCs, resulting in the RBP-Jκ-dependent expression of Jagged1 mRNA, a response that was blocked by Notch1 inhibition. Notch1 promoted the formation of cord-like structures on Matrigel. However, cigarette smoke extract inhibited this process, compared to that in control groups. Moreover, Notch1-overexpressing cells upregulated the expressing of HIF-1α gene. The HIF-1α was an angiogenic factor that clustered with Notch1, underscoring the critical role of Notch1 pathway in vessel assembly. Interestingly, this was abrogated by incubation with Notch1 shRNA.

Conclusions

Notch signaling pathway promotes differentiation of MSCs in to ECs. It also regulates angiogenesis and transcription of specific markers on ECs. These results provide a mechanism that regulates differentiation of MSCs into ECs phenotypes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01913-3.

Tumor-derived Jagged1 promotes cancer progression through immune evasion

Immune checkpoint inhibitor (ICI) therapy is generating remarkable responses in individuals with cancer, but only a small portion of individuals with breast cancer respond well. Here we report that tumor-derived Jagged1 is a key regulator of the tumor immune microenvironment. Jagged1 promotes tumorigenesis in multiple spontaneous mammary tumor models. Through Jagged1-induced Notch activation, tumor cells increase expression and secretion of multiple cytokines to help recruit macrophages into the tumor microenvironment. Educated macrophages crosstalk with tumor-infiltrating T cells to inhibit T cell proliferation and tumoricidal activity. In individuals with triple-negative breast cancer, a high expression level of Jagged1 correlates with increased macrophage infiltration and decreased T cell activity. Co-administration of an ICI PD-1 antibody with a Notch inhibitor significantly inhibits tumor growth in breast cancer models. Our findings establish a distinct signaling cascade by which Jagged1 promotes adaptive immune evasion of tumor cells and provide several possible therapeutic targets.

Transient activation of notch signaling enhances endogenous stromal cell expansion and subsequent bone defect repair

BACKGROUND

Following traumatic bone loss or removal of bone tumors, the failure of bone allograft transplantation for large bone defect repair remains a significant problem in orthopedics. Therefore, new strategies that can efficiently enhance allograft healing and long-term incorporation are critically needed.

METHOD

In this study, we first injected Notch-activating Jagged1 peptide to mice and then isolated bone marrow tissues and cells for proliferation and differentiation assays. Femur bone allograft surgery was also performed in Jagged1 pre-treated mice, and bone defect healing process were monitored by histology, Micro-CT and biomechanical testing.

RESULT

Our results showed that Jagged1 therapeutic injection is sufficient to maximally activate Notch and promote bone marrow stromal cell proliferation in vivo, while no effects on bone structure were observed. More importantly, Jagged1 pre-treatment significantly promoted bone callus formation and increased bone mechanical strength during allograft healing in a femur bone defect mouse model.

CONCLUSION

This study reveals that Notch in vivo activation can be induced by injection of Jagged1 peptide for expansion of local native stromal cells that will significantly enhance bone callus formation.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

The clinical uses of this therapeutic strategy would be immediately applicable for chronic long bone defect repair. More importantly, this devised strategy for expansion of endogenous BMSCs can also be applied to enhance other tissue and organ repair.

Alveolar progenitor differentiation and lactation depends on paracrine inhibition of notch via ROBO1/CTNNB1/JAG1

In the mammary gland, how alveolar progenitor cells are recruited to fuel tissue growth with each estrus cycle and pregnancy remains poorly understood. Here, we identify a regulatory pathway that controls alveolar progenitor differentiation and lactation by governing Notch activation in mouse. Loss of Robo1 in the mammary gland epithelium activates Notch signaling, which expands the alveolar progenitor cell population at the expense of alveolar differentiation, resulting in compromised lactation. ROBO1 is expressed in both luminal and basal cells, but loss of Robo1 in basal cells results in the luminal differentiation defect. In the basal compartment, ROBO1 inhibits the expression of Notch ligand Jag1 by regulating β-catenin (CTNNB1), which binds the Jag1 promoter. Together, our studies reveal how ROBO1/CTTNB1/JAG1 signaling in the basal compartment exerts paracrine control of Notch signaling in the luminal compartment to regulate alveolar differentiation during pregnancy.

Cooperation Between Cancer and Fibroblasts in Vascular Mimicry and N2-Type Neutrophil Recruitment via Notch2-Jagged1 Interaction in Lung Cancer

Background

Angiogenesis is required for tumor development and metastasis, which is a major part in a pro-tumor microenvironment. Vascular mimicry (VM) is a process in which cancer cells, rather than endothelia, create an alternative perfusion system to support the tumor progression.

Objectives

To validate the role of VM and to develop a strategy to inhibit angiogenesis in lung cancer.

Methods

In this study, we utilized lung cancer samples to verify the existence of VM and conducted several experimental methods to elucidate the molecular pathways.

Results

H1299 and CL1-0 lung cancer cells were unable to form capillary-like structures. VM formation was induced by cancer-associated fibroblast (CAFs) in both in vitro and in vivo experiments. Notch2–Jagged1 cell–cell contact between cancer cells and CAFs contributes to the formation of VM networks, supported by Notch intracellular domain (NICD) 2 nuclear translocation and N2ICD target gene upregulated in lung cancer cells mixed with CAFs. The polarization of tumor-promoting N2-type neutrophil was increased by VM networks consisting of CAF and cancer cells. The intravasation of cancer cells and N2-type neutrophils were increased because of the loose junctions of VM. Disruption of cancer cell–CAF connections by a γ‐secretase inhibitor enforced the anticancer effect of anti‐vascular endothelial growth factor antibodies in a mouse model.

Conclusion

This study provides the first evidence that CAFs induce lung cancer to create vascular-like networks. These findings suggest a therapeutic opportunity for improving antiangiogenesis therapy in lung cancer.

Dorsomorphin attenuates Jagged1-induced mineralization in human dental pulp cells

AIM

To investigate whether TGF-β/BMP signalling participates in Jagged1-induced osteogenic differentiation in human dental pulp cells (hDPs).

METHODOLOGY

Bioinformatic analysis of publicly available RNA sequencing data of Jagged1-treated hDPs was performed using NetworkAnalyst. The mRNA expression was validated using real-time polymerase chain reaction. hDPs were seeded on Jagged1 immobilized surfaces in the presence or absence of TGF-β or BMP inhibitor. Osteogenic differentiation was evaluated using alkaline phosphatase staining, osteogenic marker gene expression and mineralization assay. Statistical analyses were performed using a Kruskal-Wallis test, followed by a pairwise comparison for more than three group comparison. Mann-Whitney U-test was employed for two group comparison. The statistical significance was considered at p < .05.

RESULTS

Jagged1 treatment in growth medium significantly promoted TGFB1, TGFB2 and TGFB3 whilst significantly inhibited BMP2, BMP4 and BMP6 mRNA expression (p < .05). In osteogenic induction medium, Jagged1 significantly up-regulated TGFB1, TGFB2 and TGFB3 at days 1 and 3 (p < .05). Pre-treatment with TGF-β1, TGF-β2 or TGF-β3 prior to osteogenic induction resulted in the significant increase of osteogenic marker gene expression, collagen type 1 protein expression, alkaline phosphatase enzymatic activity and mineral deposition (p < .05). However, TGF-β signalling inhibition with SB431542 (4 μmol L^-1 ) or SB505124 (47 and 129 nmol L^-1 ) failed to attenuate the effect of Jagged1-induced osteogenic differentiation in hDPs. Dorsomorphin (4 and 8 μmol L^-1 ) treatment significantly abolished the effect of Jagged1 on mineralization by hDPs (p < .05).

CONCLUSION

Notch signalling activation by Jagged1 modulated TGF-β and BMP ligand expression. Dorsomorphin, but not TGF-β receptor inhibitor, attenuated Jagged1-induced osteogenic differentiation in hDPs.

Runx1/miR-26a/Jagged1 signaling axis controls osteoclastogenesis and alleviates orthodontically induced inflammatory root resorption

BACKGROUND

MicroRNAs (miRNAs) are involved in the regulation of osteoclast biology and several pathogenic progression. This study aimed to identify the role of miR-26a in osteoclastogenesis and orthodontically induced inflammatory root resorption(OIIRR).

METHODS

Rat orthodontic tooth movement (OTM) model was established by ligating a closed coil spring between maxillary first molar and incisor, and 50 g orthodontic force was applied to move upper first molar to middle for 7 days. Human periodontal ligament (hPDL) cells were isolated from periodontium of healthy donors, and then subjected to compression force (CF) for 24 h to mimic an in vitro OTM model. The levels of associated factors in vivo and in vitro were measured subsequently.

RESULT

The distance of tooth movement was increased and root resorption pits were occurred in rat OTM model. The expression of miR-26a was decreased in vivo and vitro experiments. CF treatment enhanced the secretion of inflammatory factors receptor activator of nuclear factor-kappa B ligand (RANKL) and IL-6, osteoclast marker levels, and the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts, while miR-26a overexpression reversed these results. Furthermore, miR-26a overexpression inhibited the osteoclastogenesis and rescued the root resorption in OTM rats through inhibition of Jagged1. Additionally, Runx1 could bind to miR-26a promoter and promote its expression, thereby suppressing the osteoclastogenesis.

CONCLUSION

We concluded that Runx1/miR-26a/Jagged1 signaling axis restrained osteoclastogenesis and alleviated OIIRR.

Immobilization of Jagged1 Enhances Vascular Smooth Muscle Cells Maturation by Activating the Notch Pathway

In Notch signaling, the Jagged1-Notch3 ligand-receptor pairing is implicated for regulating the phenotype maturity of vascular smooth muscle cells. However, less is known about the role of Jagged1 presentation strategy in this regulation. In this study, we used bead-immobilized Jagged1 to direct phenotype control of primary human coronary artery smooth muscle cells (HCASMC), and to differentiate embryonic multipotent mesenchymal progenitor (10T1/2) cell towards a vascular lineage. This Jagged1 presentation strategy was sufficient to activate the Notch transcription factor HES1 and induce early-stage contractile markers, including smooth muscle α-actin and calponin in HCASMCs. Bead-bound Jagged1 was unable to regulate the late-stage markers myosin heavy chain and smoothelin; however, serum starvation and TGFβ1 were used to achieve a fully contractile smooth muscle cell. When progenitor 10T1/2 cells were used for Notch3 signaling, pre-differentiation with TGFβ1 was required for a robust Jagged1 specific response, suggesting a SMC lineage commitment was necessary to direct SMC differentiation and maturity. The presence of a magnetic tension force to the ligand-receptor complex was evaluated for signaling efficacy. Magnetic pulling forces downregulated HES1 and smooth muscle α-actin in both HCASMCs and progenitor 10T1/2 cells. Taken together, this study demonstrated that (i) bead-bound Jagged1 was sufficient to activate Notch3 and promote SMC differentiation/maturation and (ii) magnetic pulling forces did not activate Notch3, suggesting the bead alone was able to provide necessary clustering or traction forces for Notch activation. Notch is highly context-dependent; therefore, these findings provide insights to improve biomaterial-driven Jagged1 control of SMC behavior.

Notch-Jagged signaling complex defined by an interaction mosaic

The Notch signaling system links cellular fate to that of its neighbors, driving proliferation, apoptosis, and cell differentiation in metazoans, whereas dysfunction leads to debilitating developmental disorders and cancers. Other than a five-by-five domain complex, it is unclear how the 40 extracellular domains of the Notch1 receptor collectively engage the 19 domains of its canonical ligand, Jagged1, to activate Notch1 signaling. Here, using cross-linking mass spectrometry (XL-MS), biophysical, and structural techniques on the full extracellular complex and targeted sites, we identify five distinct regions, two on Notch1 and three on Jagged1, that form an interaction network. The Notch1 membrane-proximal regulatory region individually binds to the established Notch1 epidermal growth factor (EGF) 8-EGF13 and Jagged1 C2-EGF3 activation sites as well as to two additional Jagged1 regions, EGF8-EGF11 and cysteine-rich domain. XL-MS and quantitative interaction experiments show that the three Notch1-binding sites on Jagged1 also engage intramolecularly. These interactions, together with Notch1 and Jagged1 ectodomain dimensions and flexibility, determined by small-angle X-ray scattering, support the formation of nonlinear architectures. Combined, the data suggest that critical Notch1 and Jagged1 regions are not distal but engage directly to control Notch1 signaling, thereby redefining the Notch1-Jagged1 activation mechanism and indicating routes for therapeutic applications.

Notch Signaling Ligand Jagged1 Enhances Macrophage-Mediated Response to Helicobacter pylori

Helicobacter pylori (H. pylori) is one of the gram-negative bacteria that mainly colonize the stomach mucosa and cause many gastrointestinal diseases, such as gastritis, peptic ulcer, and gastric cancer. Macrophages play a key role in eradicating H. pylori. Recent data have shown that Notch signaling could modulate the activation and bactericidal activities of macrophages. However, the role of Notch signaling in macrophages against H. pylori remains unclear. In the present study, in the co-culture model of macrophages with H. pylori, the inhibition of Notch signaling using γ-secretase decreased the expression of inducible nitric oxide synthase (iNOS) and its product, nitric oxide (NO), and downregulated the secretion of pro-inflammatory cytokine and attenuated phagocytosis and bactericidal activities of macrophages to H. pylori. Furthermore, we identified that Jagged1, one of Notch signaling ligands, was both upregulated in mRNA and protein level in activated macrophages induced by H. pylori. Clinical specimens showed that the number of Jagged1⁺ macrophages in the stomach mucosa from H. pylori-infected patients was significantly higher than that in healthy control. The overexpression of Jagged1 promoted bactericidal activities of macrophages against H. pylori and siRNA-Jagged1 presented the opposite effect. Besides, the addition of exogenous rJagged1 facilitated the pro-inflammatory mediators of macrophages against H. pylori, but the treatment of anti-Jagged1 neutralizing antibody attenuated it. Taken together, these results suggest that Jagged1 is a promoting molecule for macrophages against H. pylori, which will provide insight for exploring Jagged1 as a novel therapeutic target for the control of H. pylori infection.

Altered Jagged1-Notch1 Signaling in Enhanced Dysfunctional Neovascularization and Delayed Angiogenesis After Ischemic Stroke in HFD/STZ Induced Type 2 Diabetes Rats

Diabetes exacerbates brain damage in cerebral ischemic stroke. Our previous study has demonstrated that after cerebral ischemia, type 2 diabetes rats displayed worse neurological outcomes, larger cerebral infarction and severer blood-brain barrier disruption. However, our knowledge of the mechanisms of how diabetes impacts the cerebrovascular repair process is limited. This study was aimed to characterize structural alterations and potential mechanisms in brain microvessels before and after ischemic stroke in type 2 diabetic rats treated with high-fat diet and streptozotocin (HFD/STZ). Furtherly, we tested our hypothesis that dysregulated intercellular Jagged1-Notch1 signaling was involved in the dysfunctional cerebral neovascularization both before and after ischemic stroke in HFD/STZ rats. In our study, we found increased yet dysfunctional neovascularization with activated Jagged1-Notch1 signaling in the cerebrovasculature before cerebral ischemia in HFD/STZ rats compared with non-diabetic rats. Furthermore, we observed delayed angiogenesis as well as suppressed Jagged1-Notch1 signaling after ischemic stroke. Our results elucidate the potential mechanisms underlying diabetes-related cerebral microvasculature dysfunction after ischemic stroke.

Role of the Notch ligands Jagged1 and Delta4 in Th17/Treg immune imbalance in a mouse model of chronic asthma

PURPOSE

Asthma is associated with a T helper (Th)17/regulatory T (Treg) cells immune imbalance where the Notch signaling pathway contributes vitally. This study aimed to explore the role of Notch ligands Jagged1 and Delta4 in the Th17/Treg immune imbalance of chronic asthmatic mice.

METHODS

The experimental animals were randomly assigned to the Saline, ovalbumin (OVA), and OVA + γ-secretase inhibitor (GSI) groups. A mouse model of chronic asthma was induced by OVA sensitization and challenge. GSI was injected intraperitoneally before the OVA challenge in the OVA + GSI group. Lung function, lung histopathology and immunohistochemistry to assess airway inflammation, enzyme-linked immunosorbent assay to measure cytokines levels, flow cytometry to measure the proportions of Th17 (Th17%) and Treg% in CD4+T cells, quantitative real-time polymerase chain reaction and western blot to measure mRNA and protein levels of Jagged1 and Delta4 in lung tissue, and correlation analysis were performed.

RESULTS

Lung function and histopathology and IL-4, IL-13, and IFN-γ levels in the bronchoalveolar lavage fluid (BALF) of chronic asthmatic mice showed characteristic changes of asthma. The Th17%, Th17/Treg ratio, BALF and serum IL-17 levels, and IL-17/IL-10 ratio increased significantly in the OVA group, while the Treg% and IL-10 level significantly decreased. mRNA and protein expression levels of Jagged1 and Delta4 increased significantly. GSI could reduce the Th17%, Th17/Treg ratio, IL-17, IL-17/IL-10 ratio, and Jagged1 expression in chronic asthmatic mice. The mRNA and protein levels of Jagged1 and Delta4 were positively correlated with the Th17/Treg ratio in the OVA group, while only those of Jagged1 were positively correlated with the Th17/Treg ratio in the OVA + GSI group.

CONCLUSIONS

In chronic asthmatic mice, the Th17/Treg ratio increased, and the Notch ligands Jagged1 and Delta4 were overactive and positively regulated the Th17/Treg imbalance. GSI partially inhibited Jagged1 and relieved the Th17/Treg imbalance.

The role of Notch ligand Jagged1 in osteosarcoma proliferation, metastasis, and recurrence

BACKGROUND

Osteosarcoma is the most common primary bone cancer occurring in young adults and the 5-year survival rate of patients with metastatic osteosarcoma is less than 30% due to high metastatic recurrence and drug resistance. Notch is a highly conserved cell to cell signaling pathway in evolution, and Jagged1 is an important ligand of Notch. Although some studies have found that Notch receptors and ligands including Jagged1 were highly expressed in osteosarcoma tissues and osteosarcoma cells, the role of Jagged1 in osteosarcoma progression and metastasis are still not clear.

METHODS

Tumor tissues were collected from 68 patients and immunohistochemical staining was employed to group these patients by expression of Jagged1. Real-time quantitative PCR and Western blotting were used to detect the expression of Jagged1. We used siRNA to knockdown the expression of Jagged1 in F5M2 cells. Colony formation assay and MTT were employed to detect and analyze the proliferation of F5M2 cells with or without knockdown of Jagged1. Transwell assay were used to detect the migration and invasion of F5M2 cells.

RESULTS

In this study, we found that the high expression of Jagged1 is closely related to the metastasis and recurrence of osteosarcoma in 68 clinical specimens. The expression of Jagged1 in F5M2 cells with high metastasis was significantly higher than that in F4 cells with low metastasis. Knockdown of Jagged1 led to lower ability of proliferation, migration, and invasion in F5M2 cells.

CONCLUSION

The high expression of Jagged1 is closely related to the metastasis and recurrence of osteosarcoma. Knockdown of Jagged1 significantly reduced the proliferation, migration, and invasion of osteosarcoma cells. Our results suggested that knockdown of Jagged1 may be a potentially effective treatment for metastatic osteosarcoma.

lncRNA transcription factor 7 is related to deteriorating clinical features and poor prognosis in multiple myeloma, and its knockdown suppresses disease progression by regulating the miR-203-mediated Jagged1-Notch1 signaling pathway

Multiple myeloma (MM) remains a challenge to treat, and its precise pathogenic mechanisms have not been fully clarified. The present study aimed to evaluate the relation between long non-coding RNA transcription factor 7 (lnc-TCF7) and clinical features, as well as the prognosis of patients with MM, and to determine the effects of lnc-TCF7-knockdown on the regulation (and regulatory mechanisms) of MM progression. lnc-TCF7 expression was detected in the bone marrow plasma cells of 86 patients with MM and 30 healthy controls. In patients with MM, the clinical data were collected, and event-free survival (EFS) and overall survival (OS) analyses were conducted. In vitro, lnc-TCF7 expression was detected in MM cell lines and normal bone marrow plasma cells. Using Roswell Park Memorial Institute 8226 cells, functional experiments were conducted following lnc-TCF7 short hairpin (sh)RNA transfection, and compensation experiments were performed after lnc-TCF7 shRNA transfection alone and in combination with a microRNA (miR)-203 inhibitor. lnc-TCF7 expression was increased in patients with MM compared with the healthy controls and was positively related to β-2-microglobulin expression and International Staging System stage, while negatively associated with complete response, EFS and OS. In vitro, lnc-TCF7 was upregulated in MM cells compared with normal bone marrow plasma cells, and its knockdown suppressed MM cell proliferation while promoting apoptosis. Compensation experiments showed that miR-203 inhibition promoted MM progression by regulating the Jagged1-Notch1 signaling pathway in lnc-TCF7-knockdown cells. In conclusion, increased lnc-TCF7 expression was related to deteriorating clinical features and prognosis, and lnc-TCF7-knockdown inhibited disease progression by regulating the miR-203-mediated Jagged1-Notch1 signaling pathway activation in MM.

[Mitomycin C Treatment of Stromal Layers Enhances the Support of In Vitro Hematopoiesis in Co-Culture Systems]

A study was made of the effect that mitomycin C (MitC) treatment of stromal layers of NIH 3T3 cells expressing Jagged1, a ligand of the Notch receptor, exerts on the growth of hematopoietic Lin(-) mouse bone marrow cells in a co-culture system. MitC treatment of stromal cells significantly increased the number of hematopoietic cells and the frequency of colony-forming cells in stromal co-cultures. Transcriptome analysis of control and MitC-treated stromal cell samples was performed by differential RNA sequencing, and genes downregulated by MitC treatment were predominantly associated with the control of cell proliferation, the cell cycle, chromosome segregation, and DNA metabolism. Induction of key hematopoietic cytokines by MitC was not detected by the transcriptome analysis and was therefore not a main factor in the activation of hematopoiesis on the treated stroma. At the same time, the set of the genes most strongly upregulated by MitC treatment is enriched in the genes for cytokines, growth factors, and cell surface proteins, which presumably contribute to enhanced hematopoiesis support on the MitC-treated stroma. Products of some of these genes have been implicated in expansion of hematopoietic stem/progenitor cells in vitro or in vivo.

Decreased Jagged1 expression in vascular smooth muscle cells delays endothelial regeneration in arteriovenous graft

AIMS

It is well-established that endothelial dysfunction promotes activation of vascular smooth muscle cell (VSMC). Whether decreased accumulation of VSMCs affects endothelial regeneration and functions in arteriovenous graft (AVG) remodelling has not been studied. We sought to identify mechanisms by which the Notch ligand, Jagged1, in VSMCs regulates endothelial cell (EC) functions in AVGs.

METHODS AND RESULTS

AVGs were created in transgenic mice bearing VSMC-specific knockout (KO) or overexpression of Jagged1. VSMC migration, EC regeneration, and its barrier functions as well as AVG remodelling were evaluated. Jagged1 expression was induced in VSMCs of neointima in the AVGs. Jagged1 KO in VSMCs inhibited the accumulation of extracellular matrix as well as VSMC migration. Fewer α-SMA-positive VSMCs were found in AVGs created in VSMC-specific Jagged1 KO mice (VSMCJagged1 KO mice) vs. in WT mice. Decreased VSMCs in AVGs were associated with deterioration of EC functions. In AVGs created in transgenic mice bearing Jagged1 KO in VSMCs exhibited delayed EC regeneration and impaired EC barrier function. Barrier dysfunction of ECs increased inflammatory cell infiltration and dysregulation of AVG remodelling and arterialization. The increased expression of IL-1β in macrophages was associated with expression of adhesion markers in ECs in AVGs created in VSMCJagged1 KO mice. In contrast, AVGs created in mice with overexpression of Jagged1 in VSMCs exhibited improved EC regeneration plus decreased macrophage infiltration. This led to AVG remodelling and arterialization. In co-cultures of ECs and VSMCs, Jagged1 deficiency in VSMCs suppressed N-cadherin and integrin β3 expression in ECs. Inhibition of integrin β3 activation delayed EC spreading and migration. Notably, Jagged1 overexpression in VSMCs or treatment with recombinant Jagged1 stimulated the expression of N-cadherin and integrin β3 in ECs. Jagged1-induced responses were blocked by inhibition of Notch signalling.

CONCLUSIONS

Jagged1 expression in VSMCs maintains EC barrier functions and blocks infiltration of macrophages. These responses promote remodelling and arterialization of AVGs.

The Notch Ligand Jagged1 Is Required for the Formation, Maintenance, and Survival of Hensen's Cells in the Mouse Cochlea

During cochlear development, the Notch ligand JAGGED 1 (JAG1) plays an important role in the specification of the prosensory region, which gives rise to sound-sensing hair cells and neighboring supporting cells (SCs). While JAG1's expression is maintained in SCs through adulthood, the function of JAG1 in SC development is unknown. Here, we demonstrate that JAG1 is essential for the formation and maintenance of Hensen's cells, a highly specialized SC subtype located at the edge of the auditory epithelium. Using Sox2 ^CreERT2/+::Jag1^loxP/loxP mice of both genders, we show that Jag1 deletion at the onset of differentiation, at embryonic day 14.5, disrupted Hensen's cell formation. Similar loss of Hensen's cells was observed when Jag1 was deleted after Hensen's cell formation at postnatal day (P) 0/P1 and fate-mapping analysis revealed that in the absence of Jag1, some Hensen's cells die, but others convert into neighboring Claudius cells. In support of a role for JAG1 in cell survival, genes involved in mitochondrial function and protein synthesis were downregulated in the sensory epithelium of P0 cochlea lacking Jag1 Finally, using Fgfr3-iCreER^T2 ::Jag1^loxP/loxP mice to delete Jag1 at P0, we observed a similar loss of Hensen's cells and found that adult Jag1 mutant mice have hearing deficits at the low-frequency range.SIGNIFICANCE STATEMENT Hensen's cells play an essential role in the development and homeostasis of the cochlea. Defects in the biophysical or functional properties of Hensen's cells have been linked to auditory dysfunction and hearing loss. Despite their importance, surprisingly little is known about the molecular mechanisms that guide their development. Morphologic and fate-mapping analyses in our study revealed that, in the absence of the Notch ligand JAGGED1, Hensen's cells died or converted into Claudius cells, which are specialized epithelium-like cells outside the sensory epithelium. Confirming a link between JAGGED1 and cell survival, transcriptional profiling showed that JAGGED1 maintains genes critical for mitochondrial function and tissue homeostasis. Finally, auditory phenotyping revealed that JAGGED1's function in supporting cells is necessary for low-frequency hearing.

Antisense Oligonucleotides Targeting Jagged 1 Reduce House Dust Mite-induced Goblet Cell Metaplasia in the Adult Murine Lung

Goblet cell metaplasia, excessive mucus production, and inadequate mucus clearance accompany and exacerbate multiple chronic respiratory disorders, such as asthma and chronic obstructive pulmonary disease. Notch signaling plays a central role in controlling the fate of multiple cell types in the lung, including goblet cells. In the present study, we explored the therapeutic potential of modulating the Notch pathway in the adult murine lung using chemically modified antisense oligonucleotides (ASOs). To this end, we designed and characterized ASOs targeting the Notch receptors Notch1, Notch2, and Notch3 and the Notch ligands Jag1 (Jagged 1) and Jag2 (Jagged 2). Pulmonary delivery of ASOs in healthy mice or mice exposed to house dust mite, a commonly used mouse model of asthma, resulted in a significant reduction of the respective mRNAs in the lung. Furthermore, ASO-mediated knockdown of Jag1 or Notch2 in the lungs of healthy adult mice led to the downregulation of the club cell marker Scgb1a1 and the concomitant upregulation of the ciliated cell marker FoxJ1 (forkhead box J1). Similarly, ASO-mediated knockdown of Jag1 or Notch2 in the house dust mite disease model led to reduced goblet cell metaplasia and decreased mucus production. Because goblet cell metaplasia and excessive mucus secretion are a common basis for many lung pathologies, we propose that ASO-mediated inhibition of JAG1 could provide a novel therapeutic path for the treatment of multiple chronic respiratory diseases.

Linc00514 promotes breast cancer metastasis and M2 polarization of tumor-associated macrophages via Jagged1-mediated notch signaling pathway

BACKGROUND

Tumor-associated macrophages (TAMs) and tumor cells are important components of the tumor microenvironment. M2 polarization of TAMs, which is a major actor in breast cancer malignancy and metastasis, can be induced by breast cancer cells. However, the potential mechanisms of the interaction between breast cancer cells and TAMs remain unclear.

METHODS

The candidate breast cancer-associated long non-coding RNAs (lncRNAs) were analyzed using the GEO database. Functional assays, including MTT assay, Transwell assay, and EdU labeling detection, were performed to investigate the oncogenic role of linc00514 in breast cancer progression. The co-culture and ELISA assays were used to assess the role of linc00514 in macrophage recruitment and M2 polarization. RNA immunoprecipitation, RNA pull-down, and luciferase reporter assays were applied to determine the mechanism of linc00514 in breast cancer metastasis. Mouse xenograft models, mouse pulmonary metastatic models, and mouse primary tumor models were used to assess the role of linc00514 in M2 macrophage polarization and breast cancer tumorigenicity.

RESULTS

Linc00514 was highly expressed in clinical breast cancer tissues and breast cancer cell lines. Overexpression of linc00514 promoted the proliferation and invasion of breast cancer cells and increased xenograft tumor volumes and pulmonary metastatic nodules. Overexpression of linc00514 also increased the percentage of macrophages expressing M2 markers CD206 and CD163. Mechanistically, linc00514 promoted Jagged1 expression in a transcriptional manner by increasing the phosphorylation of a transcription factor STAT3. Subsequently, Jagged1-mediated Notch signaling pathway promoted IL-4 and IL-6 secretions in breast cancer cells and ultimately inducing M2 polarization of macrophages.

CONCLUSION

Linc00514 plays an important role in regulating breast cancer tumorigenicity and M2 macrophage polarization via Jagged1-mediated Notch signaling pathway.

Effects of Notch signaling components from breast cancer cells treated in culture with resveratrol

Resveratrol (Res) has an anti-tumor effect. Notch signaling components from breast cancer cells treated in culture with Resveratrol was investigated. MDA-MB-231cells were divided into control group (Res-untreated) and Res-treated groups including six concentrations 0 μM, 10 μM, 20 μM, 40 μM, 80 μM and 160 μM. Cytotoxicity test were evaluated by CCK-8. The mRNA and Protein expression levels of Notch1, Jagged1, Dll4 and Hes-5 were detected by RT-PCR and Western blot. The mRNA expression of Notch1, Jagged1, Hes-5 and Dll4 in the Res administration group decreased significantly (0.01 < p < .05), and Hes-5 and Dll4 were extremely significant (p < .01). Compared with the blank control group, the protein expression of Notch1 and Dll4 decreased significantly in each concentration Res group, but the decrease of protein expression of Jagged1 and Hes-5 was not significant. In conclusion, Res regulates mRNA and protein expression of Notch1, Dll4 of MDA-MB-231 cells via Notch pathway.

Adipose mesenchymal stem cell transplantation alleviates spinal cord injury-induced neuroinflammation partly by suppressing the Jagged1/Notch pathway

BACKGROUND

The therapeutic effects of adipose-derived mesenchymal stem cell (ADSC) transplantation have been demonstrated in several models of central nervous system (CNS) injury and are thought to involve the modulation of the inflammatory response. However, the exact underlying molecular mechanism is poorly understood. Activation of the Jagged1/Notch signaling pathway is thought to involve inflammatory and gliotic events in the CNS. Here, we elucidated the effect of ADSC transplantation on the inflammatory reaction after spinal cord injury (SCI) and the potential mechanism mediated by Jagged1/Notch signaling pathway suppression.

METHODS

To evaluate the therapeutic effects of ADSC treatment and the potential inhibitory effects of ADSCs on Notch signaling, mice were subjected to contusion SCI, and GFP-labeled ADSCs were injected into the lesion site immediately after the injury. Locomotor function, spinal cord tissue morphology, and the levels of Notch-related proteins and proinflammatory transcripts were compared between groups. To validate the hypothesis that the therapeutic effects of ADSCs are partly due to Notch1 signaling inhibition, a Jagged1 small interfering RNA (siRNA) was injected into the spinal cord to knock down Jagged1/Notch signaling. Neuronal staining and analyses of microglia/macrophage activation and signaling pathways were performed.

RESULTS

We demonstrated that ADSCs survived in the injured spinal cord for at least 28 days without differentiating into glial or neuronal elements. ADSC treatment resulted in significant downregulation of proinflammatory mediator expression and reduced ionized calcium-binding adapter molecule 1 (IBA1) and ED-1 staining in the injured spinal cord, eventually improving functional recovery. The augmentation of the Jagged1/Notch signaling pathway after SCI was suppressed by ADSC transplantation. The inhibition of the Jagged1/Notch signaling pathway by Jagged1 siRNA resulted in decreases in SCI-induced proinflammatory cytokines and the activation of microglia and an increase in the survival of neurons. Furthermore, Jagged1 knockdown suppressed the phosphorylation of JAK/STAT3 in astrocytes following SCI.

CONCLUSION

The results of this study demonstrated that the therapeutic effects of ADSCs in SCI mice were partly due to Jagged1/Notch signaling pathway inhibition and a subsequent reduction in JAK/STAT3 phosphorylation in astrocytes.

MiR-153 reduces stem cell-like phenotype and tumor growth of lung adenocarcinoma by targeting Jagged1

Background

Cancer stem cells (CSCs) have been proposed to be responsible for tumor recurrence and chemo-resistance. Previous studies suggested that miR-153 played essential roles in lung cancer. However, the molecular mechanism of miR-153 in regulating the stemness of non-small cell lung cancer (NSCLC) remains poorly understood. In this study, we investigated the role of miR-153 in regulation of the stemness of NSCLC.

Methods

The stemness property of lung stem cancer cells was detected by sphere formation assay, immunofluorescence, and Western blot. Luciferase reporter assay was performed to investigate the direct binding of miR-153 to the 3′-UTR of JAG1 mRNA. Animal study was conducted to evaluate the effect of miR-153 on tumor growth in vivo. The clinical relevance of miR-153 in NSCLC was evaluated by Rt-PCR and Kaplan-Meier analysis.

Results

MiR-153 expression was decreased in lung cancer tissues. Reduced miR-153 expression was associated with lung metastasis and poor overall survival of lung cancer patients. Jagged1, one of the ligands of Notch1, is targeted by miR-153 and inversely correlates with miR-153 in human lung samples. More importantly, we found that miR-153 inhibited stem cell-like phenotype and tumor growth of lung adenocarcinoma through inactivating the Jagged1/Notch1 axis.

Conclusion

MiR-153 suppresses the stem cell-like phenotypes and tumor growth of lung adenocarcinoma by targeting Jagged1 and provides a potential therapeutic target in lung cancer therapy.

Activation of the Notch Signaling Pathway and Cellular Localization of Notch Signaling Molecules in the Spinal Cord of SOD1-G93A ALS Model Mice

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by motor neuron loss and gliosis in the spinal cord, brain stem and cortex. The Notch signaling pathway has been reported to be dysfunctional in neurodegenerative diseases, including ALS. However, the exact mechanism is still unclear. Here, we detected Notch signaling activation in proliferating glial cells, Notch inactivation in motor neurons in the spinal cord of the SOD1-G93A model, and dramatic changes of cellular relocalization of Notch pathway signaling molecules, including activated Notch intracellular domain (NICD), Notch ligands (Jagged1 and DLL4) and the target gene Hes1. We found that Notch activation was universal in proliferating astrocytes and that the Notch ligand Jagged1 was uniquely upregulated in proliferating microglia, while DLL4 expression was increased in both activated astrocytes and degenerating oligodendrocytes. Our results indicate that microglia may play an important role in the intercellular receptor-ligand interaction of the Notch signaling pathway and contribute to the pathogenesis of motor neuron loss in ALS mice. Further experiments are required to clarify the exact mechanism responsible for Notch dysfunction in ALS.

Jagged1 and Epidermal Growth Factor Promoted Androgen-Suppressed Mouse Hair Growth In Vitro and In Vivo

Recent studies have reported that T-reg cells are intimately linked with hair follicles in a stage-dependent manner and play an important role in hair follicle cycling and regeneration in murine skin. Further study revealed that T-reg cell's regulation of hair follicle growth is through its preferential expression of the Notch ligand Jagged-1 (Jag1), which facilitates hair follicle regeneration. However, the role of Jag1 in androgen-suppressed hair growth is yet to be investigated. In addition, although epidermal growth factor (EGF) is a mitogen for cells including skin cells, whether it works synergistically with Jag1 to enhance hair follicle development is unknown. The current study intended to investigate effects of topical application of Jag1 on androgen-suppressed hair growth, and to determine the potential synergistic effect of EGF and Jag1 in this process in vivo. Fifty mice were depilated at the dorsal back area to achieve synchronized anagen development, and randomly divided into five groups with the following topical treatments control for 14 days; testosterone to induce androgenetic alopecia; Jagged1 (testosterone + Jagged1); EGF (testosterone + EGF); and Jagged1 + EGF (testosterone + Jagged1 + EGF). It was found that EGF and Jag1 by itself respectively, did not promote androgen-suppressed hair growth significantly. This stimulating effect was enhanced in the presence of both EGF and Jagged1 (p < 0.05). The hair growth promoting effect was accompanied by better follicle growth, which is associated with increased cell proliferation in the hair follicle and altered the expression of genes that are important in hair follicular cell proliferation and differentiation. Our results provide insights into the therapeutic potential of these peptides for androgenetic alopecia.

Antitumor and anti-angiogenic effects of artemisinin on breast tumor xenografts in nude mice

Breast cancer is a high incidence disease in humans. Artemisinin is an important extract that is widely used as an antimalarial drug which also serve as effective treatments for cancer. 32 nude mice were injected with 0.2 ml of MDA-MB-231 cell suspension of 2 × 10⁷ cells/ml respectively. The nude mice models were randomly divided into four groups of 8 in each group. Each group was given daily gavage, high dose group: 200 mg/kg/0.1 ml, middle dose group 100 mg/kg/0.1 ml, low dose group 50 mg/kg/0.1 ml, control group: 0.1 ml vegetable oil was fed continuously for 21 days. ELISA was used to detect serum vascular endothelial growth the content of factor VEGF and hypoxia-inducible factor HIF-1α were detected. The expression of Notch pathway-related factors in tumor tissue was detected by fluorescence quantitative assay. ELISA results showed that the serum VEGF decreased significantly in the high dose group compared with the control group (p < .01), while the other dose groups did not have significant (p > .05). The serum HIF-1α in the high dose group compared with the control group, the decrease in HIF-1α was significant (p < .05), and the other groups were not significant (p > .05). The result of fluorescence quantitative section showed that artemisinin could down-regulate the expression of notch signaling related factors notch1, Dll4 and Jagged1, and 200 mg/kg dose group had the most significant effect. It may inhibit the development of tumors by reducing serum angiogenesis-related factors VEGF, HIF-1ɑ and inhibiting the activity of notch1 signaling pathway related factors.

Preparation and characterization of Jagged1-bound fibrinogen-based microspheres and their cytotoxicity against human dental pulp cells

Surface immobilization of Jagged1 promotes odonto/osteogenic differentiation in human dental pulp cells. On the contrary, soluble Jagged1 fails to activate target gene expression of Notch signaling which is important for differentiation of human dental pulp cells. Hence, Jagged1 delivery system is indeed required for transportation of immobilized Jagged1 to promote odontogenic differentiation of human dental pulp cells in vivo. The present study described the preparation and characterization of Jagged1-bound fibrinogen-based microspheres. Water-in-oil emulsion technique was employed to prepare fibrinogen microspheres and thrombin cross-linked fibrinogen microspheres. The average size of fibrinogen microspheres and thrombin cross-linked fibrinogen microspheres was 213.9 ± 35.9 and 199.9 ± 41.9 µm, respectively. These microspheres did not alter the human dental pulp cells’ cell viability. Human dental pulp cells were able to attach and spread on these microspheres. Jagged1 was conjugated on microspheres using 1-ethyl-3-(3-dimethylamino) propyl carbodiimide/N-hydroxysuccinimide. Binding capacity of Jagged1 on both fibrinogen microspheres and thrombin cross-linked fibrinogen microspheres ranged from 25.8 ± 6.0 to 35.6 ± 9.1%. There was no significant difference in the size of microspheres between before and after Jagged1 conjugation process. In conclusion, fibrinogen microspheres and thrombin cross-linked fibrinogen microspheres could be utilized as the alternative biomaterials for Jagged1 delivery for future biomedical application.

Effects of Different Ligands in the Notch Signaling Pathway on the Proliferation and Transdifferentiation of Primary Type II Alveolar Epithelial Cells

Background: Transdifferentiation of type II alveolar epithelial cells (AECII) into type I alveolar epithelial cells (AECI) is involved in neonatal respiratory distress syndrome (NRDS). Different ligands of the Notch pathway could have different effects on AECII transdifferentiation. Objective: To investigate the effects of Dlk1 and Jagged1 on the proliferation and transdifferentiation of AECII. Methods: Fetal AECIIs (19 days of gestation) were divided: control group, Dlk1 group, rhNF-κB group. Proliferation was tested using the MTT assay. Expression of surfactant protein C (SP-C) and aquaporin 5 (AQP5) was examined by immunofluorescence. mRNA and protein levels of SP-C, AQP5, Nortch1, Dlk1, Jagged1, and Hes1 were examined by RT-PCR and western blot. Results: In response to Dlk1, cell number and proliferation were increased (P < 0.05), and mRNA and protein levels of SP-C, Dlk1, Notch1, and Hes1 were up-regulated, while AQP and Jagged1 were decreased. In response to rhNF-κB, the cell number and proliferation were reduced, and mRNA and protein levels of Jagged1 and Notch1 were up-regulated, while Dlk1, and SP-C were downregulated. In the Dlk1 group, SP-C, and AQP5 expression patterns suggested that the cells were still transdifferentiating by 96 h, while in the rhNF-κB group, most cells had transdifferentiated by 72 h and were close to apoptosis by 96 h. Conclusion: These results suggest that Dlk1 promoted proliferation of AECIIs and inhibited cell transdifferentiation, while Jagged1 treatment inhibited proliferation of AECIIs and promoted transdifferentiation to AECIs. These results provide some clue for the eventual management of NDRS.

Effect of Jagged1 on the expression of genes in regulation of osteoblast differentiation and bone mineralization ontology in human dental pulp and periodontal ligament cells

Objective

To define the effect of Jagged1 on the gene expression in osteoblast differentiation, regulation of osteoblast differentiation and regulation of bone mineralization ontology.

Methods

Human dental pulp and periodontal ligament cells were isolated using explant method. Cells were seeded on Jagged1 immobilized surface. The mRNA expression was determined using real-time polymerase chain reaction. Mineral deposition was evaluated using alizarin red s staining. Publicly available database of gene expression profiles (GSE126249 and GSE94989) were downloaded and performed bioinformatic analysis to identify gene expression in osteoblast differentiation and regulation of osteoblast differentiation and mineralization ontology.

Results

Both human dental pulp cells and human periodontal ligament cells expressed higher Notch target gene (HES1 and HEY1) when cells were seeded on Jagged1 immobilization surface. Jagged1 significantly increased an in vitro mineral deposition in both cell types after maintaining in osteogenic induction medium for 14 days. Correspondingly, the significant increase of ALPL mRNA expression was observed, while there was no significant change in ANKH and ENPP1 mRNA expression in Jagged1 treated condition. From bioinformatic analysis of genes in osteoblast differentiation ontology, IARS, COL1A1, ALPL, COL6A1, CREB3L1, and SNAI2 mRNA levels were upregulated while GJA1 mRNA levels were decreased upon Jagged1 exposure. In the regulation of bone mineralization ontology, evidences supported that TFGB1 and TGFB3 were upregulated in Jagged1 treated condition.

Conclusion

Jagged1 promote the mRNA expression of several genes in osteoblast differentiation related gene ontology. This could be further employed to identify the mechanism by which Jagged1 promoted osteogenic differentiation in human dental pulp and periodontal ligament cells.

Jagged1-mediated myeloid Notch1 signaling activates HSF1/Snail and controls NLRP3 inflammasome activation in liver inflammatory injury

Notch signaling plays important roles in the regulation of immune cell functioning during the inflammatory response. Activation of the innate immune signaling receptor NLRP3 promotes inflammation in injured tissue. However, it remains unknown whether Jagged1 (JAG1)-mediated myeloid Notch1 signaling regulates NLRP3 function in acute liver injury. Here, we report that myeloid Notch1 signaling regulates the NLRP3-driven inflammatory response in ischemia/reperfusion (IR)-induced liver injury. In a mouse model of liver IR injury, Notch1-proficient (Notch1^FL/FL) mice receiving recombinant JAG1 showed a reduction in IR-induced liver injury and increased Notch intracellular domain (NICD) and heat shock transcription factor 1 (HSF1) expression, whereas myeloid-specific Notch1 knockout (Notch1^M-KO) aggravated hepatocellular damage even with concomitant JAG1 treatment. Compared to JAG1-treated Notch1^FL/FL controls, Notch1^M-KO mice showed diminished HSF1 and Snail activity but augmented NLRP3/caspase-1 activity in ischemic liver. The disruption of HSF1 reduced Snail activation and enhanced NLRP3 activation, while the adoptive transfer of HSF1-expressing macrophages to Notch1^M-KO mice augmented Snail activation and mitigated IR-triggered liver inflammation. Moreover, the knockdown of Snail in JAG1-treated Notch1^FL/FL livers worsened hepatocellular functioning, reduced TRX1 expression and increased TXNIP/NLRP3 expression. Ablation of myeloid Notch1 or Snail increased ASK1 activation and hepatocellular apoptosis, whereas the activation of Snail increased TRX1 expression and reduced TXNIP, NLRP3/caspase-1, and ROS production. Our findings demonstrated that JAG1-mediated myeloid Notch1 signaling promotes HSF1 and Snail activation, which in turn inhibits NLRP3 function and hepatocellular apoptosis leading to the alleviation of IR-induced liver injury. Hence, the Notch1/HSF1/Snail signaling axis represents a novel regulator of and a potential therapeutic target for liver inflammatory injury.

Pyrroloquinoline quinone delays inflammaging induced by TNF-α through the p16/p21 and Jagged1 signalling pathways

Previous studies on the longevity effect of pyrroloquinoline quinine (PQQ) on nematode worms have revealed that PQQ can enhance the antioxidant capacity of nematode worms, thus extending the lifespan of the worms. The induction and development of cellular senescence are closely connected with inflammatory reactions. The aim of this study was to determine the effect of PQQ and ageing factors on senescent cells. To this end, we cultivated human embryonic lung fibroblasts in nutrient solution with or without tumour necrosis factor-alpha (TNF-α) to establish an inflammaging model in vitro. The cells were preincubated with or without PQQ to determine if PQQ had any anti-inflammaging effect. More senescent cells were detected with the addition of TNF-α than without (P < .01). The ratio of senescent cells to non-senescent cells in the TNF-α group was greater than that in the control group (P < .01). When cells were preincubated with PQQ prior to TNF-α treatment, there were fewer senescent cells than those in the control group, which was not pretreated with PQQ (P < .05). The same tendency was noted with regard to p21, p16, and Jagged1. In summary, we used TNF-α, a well-known pro-inflammatory cytokine associated with inflammaging, to establish an in vitro inflammaging model and provided evidence that PQQ delays TNF-α -induced cellular senescence and has anti-inflammaging properties.

Blocking development of liver fibrosis augments hepatic progenitor cell-derived liver regeneration in a mouse chronic liver injury model

AIM

The roles of hepatic progenitor cells (HPCs) in regeneration of a diseased liver are unclear. Hepatic stellate cells (HSCs) contribute to liver fibrosis but are also a component of the HPC niche. Hepatic progenitor cells expand along with HSC activation and liver fibrosis. However, little is known about the interplay of liver fibrosis and HPC-mediated liver regeneration. This study aimed to investigate HSCs and HPCs in liver regeneration.

METHODS

Liver injury in mice was induced with 3,5-diethoxycarbonyl-1,4-dihydrocollidine, and HPC expansion and fibrosis were assessed. An angiotensin II type 1 receptor blocker (ARB) was administered to assess its effect on fibrosis and regeneration.

RESULTS

Treatment with ARB attenuated fibrosis and expansion of α-smooth muscle actin-positive activated HSCs as indicated by increased liver weight and Ki-67-positive hepatocytes. Immunohistochemical staining suggested that HPC differentiation was shifted toward hepatocytes (HCs) when ARB treatment decreased HPC encapsulation by HSCs and extracellular matrix. Conditioned medium produced by culturing the human HSC LX-2 line strongly augmented differentiation to biliary epithelial cells (BECs) but inhibited that to HCs. Activated HSCs expressed Jagged1, a NOTCH ligand, which plays a central role in differentiation of HPCs toward BECs.

CONCLUSIONS

Hepatic stellate cells, the HPC niche cells, control differentiation of HPCs, directing them toward BECs rather than HCs in a diseased liver model. Antifibrosis treatment with an ARB preferentially redirects HPC differentiation toward HCs by blocking the NOTCH pathway in the HPC niche, resulting in more efficient HPC-mediated liver regeneration.

Mouse Models for Diseases in the Cholangiocyte Lineage

Cholangiopathies are an important group of liver diseases affecting the biliary system, and the purpose of this review is to describe how diseases in the biliary system can be studied in mouse models. A particular focus is placed on mouse models for Alagille syndrome, a cholangiopathy with a strong genetic link to dysfunctional Notch signaling. Recently, a number of different genetic mouse models based on various manipulations of the Notch signaling pathway have been generated to study Alagille syndrome, and we discuss the resulting phenotypes, and possible causes for the phenotypic heterogeneity among the various models. In the final section, we provide a more general discussion on how well mouse models can be expected to mimic human liver disease, as well as an outlook toward the need for new technologies that can help us to gain new insights from mouse models for liver disease.

Knockdown of DANCR reduces osteoclastogenesis and root resorption induced by compression force via Jagged1

LncRNA DANCR has been proven to be involved in osteoblast differentiation. This study aims to investigate the role of DANCR in osteoclast formation and root resorption in periodontal ligament (PDL) cells induced by compression force (CF). Rat orthodontic tooth movement (OTM) model was established. The molecules expressions in the areas of root resorption form OTM model were measured. The number of osteoclasts was measured using Tartrate-resistant acid phosphatase (TRAP) staining. The bone resorption was detected using pit formation assay. We showed that the expression of DANCR and Jagged1 protein was increased in rat OTM model and human periodontal ligament (hPDL) cells treated with CF, and CF increased the production of Jagged1, RANKL, and IL-6 from the hPDL cells. Moreover, DANCR could positively regulate Jagged1 protein expression. Knockdown of DANCR could change the promotion effect of CF on osteoclastogenesis and bone resorption in vitro and in vivo experiments, while overexpression of Jagged1 reversed si-DANCR effect. Taken together, knockdown of DANCR reduced osteoclast formation and root resorption induced by CF via Jagged1.

Demyelination-Remyelination in the Central Nervous System: Ligand-Dependent Participation of the Notch Signaling Pathway

Multiple sclerosis (MS) is an immune-mediated CNS disease mostly affecting young people. MS and other neurodegenerative and white matter disorders involve oligodendrocyte (OL) damage and demyelination. Therefore, elucidating the signaling pathways involved in the remyelination process through the maturation of OL progenitor cells (OPCs) may contribute to the development of new therapeutic approaches. In this context, this paper further characterizes toxic cuprizone (CPZ)-induced demyelination and spontaneous remyelination in rats and investigates the role of ligand-dependent Notch signaling activation along demyelination/remyelination both in vivo and in vitro. Toxic treatment generated an inflammatory response characterized by both microgliosis and astrogliosis. Interestingly, early demyelination revealed an increase in the proportion of Jagged1+/GFAP+ cells, which correlated with an increase in Jagged1 transcript and concomitant Jagged1-driven Notch signaling activation, particularly in NG2+ OPCs, in both the corpus callosum (CC) and subventricular zone (SVZ). The onset of remyelination then exhibited an increase in the proportion of F3/contactin+/NG2+ cells, which correlated with an increase in F3/contactin transcript during ongoing remyelination in the CC. Moreover, neurosphere cultures revealed that neural progenitor cells (NPCs) present in the brain SVZ of CPZ-treated rats recapitulate in vitro the mechanisms underlying the response to toxic injury observed in vivo, compensating for mature OL loss. Altogether, the present results offer strong evidence of cell-type and ligand-specific Notch signaling activation and its time- and area-dependent participation in toxic demyelination and spontaneous remyelination.

Role of Jagged1/STAT3 signalling in platinum-resistant ovarian cancer

Jagged1, the essential ligand of the Notch signalling pathway, is highly expressed in metastatic prostate cancer, and its high expression in breast cancer is linked to poor survival rates. However, the mechanism of Jagged1′s involvement in platinum‐resistant ovarian cancer has not been thoroughly elucidated to date. The purpose of the present study was to investigate the roles of Jagged1 in the platinum resistance of ovarian cancer and its possible mechanisms. Compared with a platinum responsive group of ovarian epithelial cell carcinomas, we found the positive staining intensity of Notch1, Notch2, Jagged1, STAT3 and Epithelial‐mesenchymal transition (EMT) proteins were lower in a platinum‐resistant group. The DDP‐resistant ovarian cancer cell line (C13K) had a higher IC50 of DDP than its parental cell line (OV2008) (P < 0.05) and acquired an EMT phenotype and invasive characteristics. Inhibiting or knockdown of Jagged1 expression could not only reduce its capacity of migration and invasion but also reverse EMT and down‐regulate the expression of serine 727‐phosphorylated STAT3 (pS727) at the protein level but not total STAT3 or tyrosine 705‐phosphorylated STAT3 (pY705) in C13K cells. Furthermore, it was found that crosstalk between the Jagged1/Notch and JAK/STAT3 signalling pathways were involved in Jagged1‐promoting EMT in C13K cells. Experiments in vivo showed a reduced micrometastatic tumour burden in the lung, liver and spleen of mice implanted with C13K cells with knocked‐down Jagged1 compared with mice implanted with control cells. All of these results demonstrate that Jagged1 can crosstalk with the JAK/STAT3 pathway, and they all cooperate to promote the aberrant occurrence of EMT, further reinforcing the abilities of invasion and migration of platinum‐resistant ovarian cancer in vivo and in vitro.

DLL4 and Jagged1 are angiogenic targets of orphan nuclear receptor TR3/Nur77

Pathological angiogenesis is a hallmark of many diseases. Previously, we reported that orphan nuclear receptor TR3/Nur77 was a critical mediator of angiogenesis to regulate tumor growth and skin wound healing via regulating the expression of the junctional proteins and integrins. However, the molecular mechanism, by which TR3/Nur77 regulates angiogenesis is not completely understood. Here, we were the first to find that TR3/Nur77, via its various amino acid fragments, regulated the expression of DLL4 and Jagged 1 in cultured endothelial cells. DLL4 and Jagged1 mediated TR3/Nur77-induced angiogenic responses and signaling molecules, but not the expression of integrins. Instead, integrins regulated the expressions of DLL4 and Jagged1 induced by TR3/Nur77. Further, DLL4, Jagged1 and integrins α1, α2, β3 and β5 were regulated by TR3/Nur77 in animal sepsis models of lipopolysaccharide (LPS)-induced endotoxemia, and cecal ligation and puncture (CLP), in which, TR3/Nur77 expression was significantly and tranciently increased. Mouse survival rates were greatly increased in Nur77 knockout mice bearing both CLP and LPS models. The results elucidated a novel axis of VEGF/histamine ➔ TR3/Nur77 ➔ integrins ➔ DLL4/Jagged1 in angiogenesis, and demonstrated that TR3/Nur77 was an excellent target for sepsis. These studies supported our previous findings that TR3/Nur77 was an excellent therapeutic target, and further our understanding of the molecular mechanism, by which TR3/Nur77 regulated angiogenesis.

Jagged1 protein processing in the developing mammalian lens

Notch signaling regulates a multitude of cellular processes. During ocular lens development this pathway is required for lens progenitor growth, differentiation and maintenance of the transition zone. After ligand-receptor binding, the receptor proteins are processed, first by ADAM proteases, then by γ-secretase cleavage. This results in the release of a Notch intracellular domain (N-ICD), which is recruited into a nuclear transcription factor complex that activates Notch target genes. Previous in vitro studies showed that the Delta-like and Jagged ligand proteins can also be cleaved by the γ-secretase complex, but it remains unknown whether such processing occurs during in vivo vertebrate development. Here we show that mouse and human lens progenitor cells endogenously express multiple Jagged1 protein isoforms, including a Jagged1 intracellular domain. We also found that pharmacologic blockage of γ-secretase activity in vitro resulted in an accumulation of Jagged1 polypeptide intermediates. Finally, overexpression of an epitope-tagged Jagged1 intracellular domain displayed nuclear localization and induced the upregulation of endogenous JAG1 mRNA expression. These findings support the idea that along with its classical role as a Notch pathway ligand, Jagged1 is regulated post-translationally, to produce multiple active protein isoforms.

Summary: The Notch pathway ligand protein Jagged1 undergoes multiple catalytic cleavages, regulated by Adam proteases and the gamma-secretase complex, during mammalian lens development, similar to Notch receptor proteins.